RU2836841C2 - Encoding and decoding method, encoder and decoder - Google Patents

Abstract

FIELD: video encoding means.

SUBSTANCE: identification information on the change in location of the last significant coefficient of the current slice and information on the coordinates of the last significant coefficient of the current block of the blocks in the current slice are determined. In response to identification information indicating that change of location by inverse of the last significant coefficient is applied to blocks of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to information on coordinates of the last significant coefficient. Coefficients of the current block are determined by decoding the coefficients located before the location of the last significant coefficient in a given scanning order. In response to the fact that the value of the first identification information on the change of location by the inverse of the last significant coefficient is the first value, determining that reversal of the last significant coefficient is applied to each of the luminance component, the first chrominance component and the second chrominance component of the current slice.

EFFECT: high efficiency of video encoding.

13 cl, 17 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] Embodiments of the present invention relate to the field of video encoding and decoding technologies and, in particular, to an encoding method, a decoding method, a bitstream, an encoder, a decoder and a computer storage medium.

PREREQUISITES FOR THE CREATION OF THE INVENTION

[0002] The field of computer vision has attracted increasing attention due to the increasing requirements for video display quality. Recently, image processing technology has been successfully applied in all walks of life. In video image encoding and decoding, on the encoder side, the image data to be encoded is subjected to compression encoding by an entropy encoding unit after being subjected to transformation and quantization processing, and the bit stream generated as a result of the entropy encoding is transmitted to the decoder; on the decoder side, the bit stream is analyzed, and then the originally input image data can be restored by performing inverse quantization and inverse transformation.

[0003] At present, encoding and decoding of high bit depth, high quality and high bit rate video (abbreviated as triple high definition video) generally requires more coefficients to be encoded and decoded, and the coefficients are also larger than encoding and decoding of low bit depth, low quality and low bit rate video (which may be called normal video). Accordingly, for triple high definition video, the existing corresponding solution may result in greater resource consumption in the bitstream, resulting in wasteful use.

ESSENCE OF THE INVENTION

[0004] Embodiments of the present invention provide an encoding method, a decoding method, a bitstream, an encoder, a decoder, and a computer storage medium that can be applied to a scenario of encoding and decoding video with high bit depth, high bit rate, high quality, or lossless compression, and can improve compression efficiency.

[0005] The technical solutions according to the embodiments of the present invention can be implemented as follows.

[0006] In a first aspect, embodiments of the present invention provide a decoding method performed by a decoder. The method includes the following operations.

[0007] Identification information about the component of the current slice and information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice are determined by analyzing the bitstream.

[0008] In response to identification information about a component indicating that a reversal of the location of the last significant coefficient is applied to a component of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to the coordinate information of the last significant coefficient.

[0009] The coefficients of the current block are determined by decoding all coefficients located above the location of the last significant coefficient, in a given scan order.

[0010] In a second aspect, embodiments of the present invention provide an encoding method performed by an encoder. The method includes the following operations.

[0011] Determine identification information about a component of the current slice and the location of the last significant coefficient of the current block corresponding to the component of the current slice.

[0012] Determine coordinate information of the last significant coefficient of the current block according to identification information of the component and the location of the last significant coefficient.

[0013] All coefficients located above the location of the last significant coefficient are encoded in a given scanning order, and bit information obtained through the encoding, identification information about the component, and information about the coordinates of the last significant coefficient are provided to the bit stream.

[0014] In a third aspect, embodiments of the present invention provide a bit stream. The bit stream is generated by performing bit encoding on information to be encoded. The information to be encoded comprises at least one of first identification information about a syntax element, second identification information about a syntax element, third identification information about a syntax element, identification information about a component, identification information about a resolved last coefficient, or identification information about a default encoded sub-block.

[0015] The first identification information about the syntax element indicates whether the reversal of the last significant coefficient is allowed for the current sequence. The second identification information about the syntax element indicates whether a version of the standard extension is applied to the current sequence. The third identification information about the syntax element indicates whether a range extension is applied to the current sequence. The identification information about the component indicates whether the reversal of the last significant coefficient is applied to the component of the current slice. The identification information about the allowed last coefficient indicates whether the location of the last coefficient is applied to the current block. The identification information about the default coded sub-block indicates whether the sub-block to be coded is coded by default in the current block. The current sequence contains the current slice. The current slice contains the current block.

[0016] In a fourth aspect, in embodiments of the present invention, an encoder is provided. The encoder comprises a first determining unit and an encoding unit.

[0017] The first determining unit is configured to determine identification information about a component of the current slice and to determine the location of the last significant coefficient of the current block corresponding to the component of the current slice.

[0018] The first determining unit is further configured to determine information about the coordinates of the last significant coefficient of the current block according to the identification information about the component and the location of the last significant coefficient.

[0019] The encoding unit is configured to encode all coefficients located above the location of the last significant coefficient in a given scanning order and to provide in the bit stream the bit information obtained by encoding, the identification information about the component and the information about the coordinates of the last significant coefficient.

[0020] In a fifth aspect, in embodiments of the present invention, an encoder is provided. The encoder comprises a first memory device and a first processor.

[0021] The first storage device is configured to store thereon a computer program executed by the first processor.

[0022] The first processor is configured to execute a computer program for performing the encoding method according to the second aspect.

[0023] In a sixth aspect, embodiments of the present invention provide a decoder. The decoder comprises an analysis unit and a second determination unit.

[0024] The analysis unit is configured to determine, by analyzing the bit stream, identification information about the component of the current slice and information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice.

[0025] The second determining unit is configured to obtain the location of the last significant coefficient of the current block by performing a calculation with respect to information about the coordinates of the last significant coefficient in response to identification information about the component indicating that a change in the location to the inverse of the last significant coefficient is applied to the component of the current slice.

[0026] The analysis unit is further configured to determine the coefficients of the current block by decoding all coefficients located above the location of the last significant coefficient, in a given scanning order.

[0027] In a seventh aspect, embodiments of the present invention provide a decoder. The decoder comprises a second memory device and a second processor.

[0028] The second storage device is configured to store thereon a computer program executed by the second processor.

[0029] The second processor is configured to execute a computer program for performing the decoding method according to the first aspect.

[0030] In an eighth aspect, in embodiments of the present invention, a computer storage medium is provided. The computer storage medium has a computer program stored thereon. When executed, the computer program implements the method according to the first aspect or the method according to the second aspect.

[0031] In embodiments of the present invention, an encoding method, a decoding method, a bit stream, an encoder, a decoder and a computer storage medium are provided. The encoder determines identification information about a component of a current slice and a location of the last significant coefficient of a current block corresponding to the component of the current slice; determines coordinate information of the last significant coefficient of the current block according to the identification information about the component and the location of the last significant coefficient; and codes all coefficients located above the location of the last significant coefficient in a given scanning order, and provides bit information obtained by encoding, the identification information about the component and the coordinate information of the last significant coefficient to a bit stream. The decoder determines, by analyzing the bit stream, the identification information about the component of the current slice and the coordinate information of the last significant coefficient of the current block corresponding to the component of the current slice; in response to the component identification information indicating that the reversal of the location of the last significant coefficient is applied to the component of the current slice, obtains the location of the last significant coefficient of the current block by performing a calculation with respect to the coordinate information of the last significant coefficient; and determines the coefficients of the current block by decoding all the coefficients located above the location of the last significant coefficient in a predetermined scanning order. In this way, in the scenario of encoding and decoding video with a high bit depth, high bit rate, high quality or lossless video, a reasonable acquisition mode of the last significant coefficient is set according to the distribution law of the significant coefficients, which can reduce the consumption of resources caused by encoding in a bitstream and thus improve the compression efficiency. In addition, since the corresponding color components may be different in the distribution of the significant coefficients, the corresponding component identification information can be used to control the corresponding acquisition mode of the last significant coefficient for each color component, i.e. separate control over whether to apply the last significant coefficient reversal technique to each color component, thereby further improving compression efficiency.

BRIEF DESCRIPTION OF GRAPHIC MATERIALS

[0032] Fig. 1 shows a diagram of the application of the coding system in the prior art.

[0033] Fig. 2 shows a diagram of the relationship between the location of the current coefficient and the location of the neighboring coefficient in the prior art.

[0034] Fig. 3 shows a block diagram of a process for arithmetic decoding of a binary number in the prior art.

[0035] Fig. 4 is a block diagram of a process for arithmetic decoding of a binary symbol in the prior art.

[0036] Fig. 5 shows a block diagram of the renormalization of the arithmetic decoding mechanism in the prior art.

[0037] Fig. 6 shows a flow chart of a bypass decoding process in the prior art.

[0038] Fig. 7 is a diagram showing the relationship between the location of the region containing the possible significant coefficient and the location of the zero output region in the prior art.

[0039] Fig. 8A is a diagram of the structure of an encoder system according to embodiments of the present invention.

[0040] Fig. 8B is a diagram of the structure of a decoder system according to embodiments of the present invention.

[0041] Fig. 9 is a flow chart of a decoding method according to embodiments of the present invention.

[0042] Fig. 10A is a diagram showing the location of the last significant coefficient in relation to the upper left corner of the current block according to embodiments of the present invention.

[0043] Fig. 10B is a diagram showing the location of the last significant coefficient in relation to the lower right corner of the current block according to embodiments of the present invention.

[0044] Fig. 11 is a flow chart of a coding method according to embodiments of the present invention.

[0045] Fig. 12 is a diagram of the structure of an encoder according to embodiments of the present invention.

[0046] Fig. 13 is a diagram of a hardware structure of an encoder according to embodiments of the present invention.

[0047] Fig. 14 is a diagram of the structure of a decoder according to embodiments of the present invention.

[0048] Fig. 15 is a diagram of a hardware structure of a decoder according to embodiments of the present invention.

DETAILED DESCRIPTION

[0049] Embodiments of the present invention are described hereinafter with reference to drawings in order to provide a deeper understanding of the features and technical content of each embodiment herein. The drawings provided herein are for reference and explanation only and are not intended to limit the embodiments of the present invention.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art of the present invention. The terms used in the technical description of the present invention are only intended to describe a particular embodiment and are not intended to limit the present invention.

[0051] In the following description, "some embodiment(s)" describes a subset of all possible embodiments. However, it is understood that "some embodiment(s)" may be the same subset of all possible embodiments or different subsets of all possible embodiments, and may be combined with each other if the combination does not result in a contradiction. It should also be noted that in the embodiments of the present invention, the terms "first/second/third" are used only to distinguish between similar objects and do not denote a specific order of objects. It is understood that, where permitted, "first/second/third" in a specific order is interchangeable to allow the embodiments of the present invention described herein to be implemented in an order different from that shown or described herein.

[0052] In a video image, a coding unit (CU) is usually designated by a first color component, a second color component, and a third color component. The three color components may be a luminance component, a blue chroma component, and a red chroma component, respectively. In particular, the luminance component is generally designated as Y. The blue chroma component may be generally designated as Cb or U. The red chroma component may be generally designated as Cr or V. Thus, a video image may be expressed in the YCbCr format or in the YUV format.

[0053] Before further describing the embodiments of the present invention, the names and terms used in the embodiments of the present invention are explained as follows:

[0054] Moving Picture Experts Group (MPEG),

[0055] Joint Video Engineering Team (JVET),

[0056] Alliance for Open Media (AOM),

[0057] H.266 next-generation video coding standard/Versatile Video Coding (VVC),

[0058] VVC reference software test platform (VVC test model, VTM),

[0059] Audio and Video Standard (AVS),

[0060] AVS High Performance Model (High Performance Model, HPM),

[0061] context-based adjustable binary arithmetic coding (CABAC),

[0062] Raw Byte Sequence Payload (RBSP),

[0063] regular residual coding (RRC) and

[0064] skip residual coding transform (TSRC).

[0065] It is understood that currently all universal video coding standards (e.g. VVC) use a hybrid block-based coding system. Each video image can be divided into largest coding units (LCU), which are squares of the same size, for example, 128×128, 64×64, etc. Each LCU can be further divided into coding units (CU), which are rectangles, according to a certain rule. In addition, the CU can be further divided into smaller prediction nodes (PU), transform nodes (TU), etc. In particular, as shown in FIG. 1, the hybrid coding system can include modules such as prediction, transform, quantization, entropy coding, loop filter, etc. The prediction module can include intra prediction and intermediate prediction. The intermediate prediction can include motion estimation (ME) and motion compensation (MC). Since adjacent pixels in a video image are highly correlated with each other, the spatial redundancy between adjacent pixels can be eliminated by intra prediction in video coding technology. However, since adjacent video images are very similar, the temporal redundancy between adjacent images can be eliminated by intermediate prediction in video coding technology, thereby improving the coding and decoding efficiency.

[0066] The basic operation scheme of the video codec is as follows. In the encoder, an image may be divided into blocks. A prediction block of the current block may be obtained by performing intra prediction or intermediate prediction on the current block. A residual block may be obtained by subtracting the prediction block from the raw block of the current block. A quantization coefficient matrix may be obtained by performing transform and quantization on the residual block. Entropy coding may be performed on the quantization coefficient matrix, and the result obtained as a result of the entropy coding may be provided to the bitstream. In the decoder, a prediction block of the current block may be obtained by performing intra prediction or intermediate prediction on the current block. On the other hand, the quantization coefficient matrix may be obtained by decoding the bitstream. The residual block may be obtained by performing inverse quantization and inverse transform on the quantization coefficient matrix. The reconstructed block may be obtained by adding the prediction block and the residual block. The reconstructed image may consist of the reconstructed blocks. The decoded image can be obtained by performing loop filtering on an image basis or on a block basis on the reconstructed image. The encoder also needs to obtain the decoded image by operations similar to the decoder. The decoded image can be taken as a reference image for intermediate prediction for a subsequent image. Information on block division, mode information or information on parameters of prediction, transformation, quantization, entropy coding, loop filter, etc., which are determined by the encoder, need to be provided in the bit stream, if necessary. Then, by analyzing the bit stream and analyzing the available information, the decoder can determine the information on block division as well as mode information or information on parameters of prediction, transformation, quantization, entropy coding, loop filter, etc., which are similar to those determined by the encoder, thereby ensuring that the decoded image obtained by the encoder is similar to the decoded image obtained by the decoder. The decoded image obtained by the encoder may also be generally referred to as a reconstructed image. In prediction, the current block may be divided into PU. In transformation, the current block may be divided into TU. The division of PU and the division of TU may be different. The above is the basic operation scheme of the video codec in the hybrid block-based coding system. With the development of technology, some modules or some stages of the system or flow may be optimized. Embodiments of the present invention are applicable to the basic operation scheme of the video codec in the hybrid block-based coding system, but are not limited thereto.

[0067] In embodiments of the present invention, the current block may be the current CU, the current PU, or the current transform unit (TU), etc. Block partition information, prediction, transform, and quantization mode and parameter information, and coefficients, etc. may be provided in a bitstream by entropy coding. Assume that the probabilities of different elements are different. A short codeword may be assigned to an element whose occurrence probability is higher. A long codeword may be assigned to an element whose occurrence probability is lower. This increases the coding efficiency compared to fixed-length coding. However, the compression space in entropy coding is limited if the probabilities of different elements are close or essentially the same. CABAC is a commonly used entropy coding. In each of high efficiency video coding (HEVC), VVC, etc., entropy coding is performed by CABAC. In CABAC, a context model may be used, which increases the compression efficiency. However, using and updating the context mode also complicates the operation. A bypass mode may be provided in CABAC. In the bypass mode, there is no need to use and update the context model, which provides higher throughput. In embodiments of the present invention, the mode in which the context model must be used and updated in CABAC may be called the context mode.

[0068] Typically, it is necessary to determine a context model first according to a certain method. The parameter of the context model may be taken as an input when calling a certain process of arithmetic decoding of a binary symbol. The selection of the context model may also depend on the neighboring coefficients. For example, Fig. 2 shows a diagram of the relationship between the location of the current coefficient and the location of the neighboring coefficient in the prior art. In Fig. 2, a block filled with black color denotes the current coefficient. A block filled with grid lines denotes the neighboring coefficient. As shown in Fig. 2, the context model selected for sig_coeff_flag of the current coefficient must be determined according to the information of 5 neighboring coefficients to the right of the current coefficient, below the current coefficient, and below the right of the current coefficient. In addition, it can be seen from Fig. 2 that the operation in the context mode is much more complicated than in the bypass mode and additionally depends on the neighboring coefficients.

[0069] To use the context mode, the CABAC arithmetic coding engine must call a certain process of arithmetic decoding of the binary symbol. The process may include a state transition process, i.e., updating the context model. During the arithmetic decoding process of the binary symbol, a renormalization process of the arithmetic decoding engine may be called. When using the bypass mode, it is necessary to call the bypass decoding process.

[0070] The application of CABAC in VVC is presented below as an example.

[0071] For the CABAC arithmetic coding engine, ctxTable, ctxIdx, bypassFlag, and the ivlCurrRange and ivlOffset state variables of the arithmetic decoding engine may be input into the arithmetic decoding process. The arithmetic decoding process may output the value of the binary number.

[0072] In this document, ctxTable may be a table used in selecting a context mode, and ctxIdx may be an index of a context model.

[0073] Fig. 3 is a flow chart of a process of arithmetic decoding of a binary number in the prior art. As shown in Fig. 3, in order to obtain a value of a binary number through decoding, a context index table ctxTable, a context model index ctxIdx, a bypass mode enabling flag bypassFlag can be transmitted and input into the arithmetic decoding process DecodeBin(ctxTable, ctxIdx, bypassFlag), specifically, as follows.

[0074] The DecodeBypass() bypass decoding process can be called if the bypassFlag value is 1.

[0075] Otherwise, if the bypassFlag value is 0, the ctxTable value is 0, and the ctxIdx value is 0, the DecodeTerminate() decoding termination process may be called.

[0076] Otherwise (if the bypassFlag value is 0 and the ctxTable value is not 0), a specific process, DecodeDecision(ctxTable, ctxIdx), of arithmetic decoding of the binary symbol may be called.

[0077] Additionally, the variables ctxTable, ctxIdx, ivlCurrRange, and ivlOffset may be input to the binary symbol arithmetic decoding process. The binary symbol arithmetic decoding process may output the binVal value obtained through decoding, as well as updated ivlCurrRange and ivlOffset variables.

[0078] Fig. 4 is a flow chart of a process of arithmetic decoding of a binary symbol in the prior art. As shown in Fig. 4, the context index table ctxTable and the context model index ctxIdx, as well as the state variables ivlCurrRange and ivlOffset of the arithmetic decoding engine can be input through DecodeDecision(ctxTable, ctxIdx). In this document, pStateIdx0 and pStateIdx1 may be two current states of the context model.

[0079] (1) The value of the ivlLpsRange variable can be obtained as follows.

[0080] The qRangeIdx variable can be obtained as follows, given the current value of ivlCurrRange.

[0081] qRangeIdx=ivlCurrRange >>5

[0082] valMps and ivlLpsRange can be obtained as follows, given qRangeIdx and pStateIdx0, as well as pStateIdx1, corresponding to ctxTable and ctxIdx.

[0083] pState=pStateIdx1+16×pStateIdx0;

[0084] valMps=pState >>14;

[0085] ivlLpsRange=(qRangeIdx×((valMps ? 32767-pState: pState) >>9) >>1) +4.

[0086] (2) The value of the ivlCurrRange variable can be set as ivlCurrRange-ivlLpsRange. The following operations can be performed.

[0087] If ivlOffset is greater than or equal to ivlCurrRange, the value of the binVal variable may be 1-valMps, and the ivlOffset and ivlCurrRange variables may be updated. In this case, the value of ivlOffset may be ivlOffset minus ivlCurrRange, and the value of ivlCurrRange may be ivlLpsRange.

[0088] Otherwise (if ivlOffset < ivlCurrRange), the value of the binVal variable may be valMps.

[0089] Given the value of binVal, a certain statetransition may be performed. A certain renormalization may be performed based on the current value of ivlCurrRange.

[0090] Additionally, the present pStateIdx0 and pStateIdx1, as well as the binVal obtained by decoding, may be input into the state transition process. The state transition process may output context variables pStateIdx0 and pStateIdx1 corresponding to the updated ctxTable and ctxIdx. In this document, the variables shift0 and shift1 may be obtained from shiftIdx. In this document, the correspondence between shiftIdx and ctxTable, as well as ctxIdx, may be defined as follows.

[0091] shift0=(shiftIdx >>2) +2;

[0092] shift1=(shiftIdx& 3) +3+shift0.

[0093] Based on the value of binVal obtained through decoding, two variables pStateIdx0 and pStateIdx1 corresponding to ctxTable and ctxIdx may be updated as follows.

[0094] pStateIdx0=pStateIdx0-(pStateIdx0 >>shift0) +(1023×binVal >>shift0);

[0095] pStateIdx1=pStateIdx1-*(pStateIdx1>>shift1) +(16383×binVal >>shift1).

[0096] Additionally, the ivlCurrRange and ivlOffset variables, as well as the bits in the slice data, may be input to the renormalization process of the arithmetic decoding engine. The renormalization process may output updated ivlCurrRange and ivlOffset variables.

[0097] Fig. 5 shows a block diagram of the renormalization of the arithmetic decoding mechanism in the prior art. As shown in Fig. 5, a thread may enter the ReNormD process. The current value of ivlCurrRange may be preferably compared with 256. The subsequent operations may be as follows.

[0098] If ivlCurrRange is greater than or equal to 256, renormalization is not needed and the RenormD process terminates.

[0099] Otherwise (if ivlCurrRange is less than 256), the flow may enter a renormalization loop. In the loop, the value of ivlCurrRange may be multiplied by 2, i.e. moved left by one bit. The value of IvlOffset may be multiplied by 2, i.e. moved left by one bit. One bit obtained with read_bits(1) may be moved into ivlOffset, specifically as follows.

[00100] ivlCurrRange=ivlCurrRange<<1;

[00101] ivlOffset =ivlOffset <<1;

[00102] ivlOffset =ivlOffset |read_bits(1).

[00103] During the entire process, the data in the bitstream must not cause ivlOffset to be greater than or equal to ivlCurrRange.

[00104] Additionally, the ivlCurrRange and ivlOffset variables, as well as the slice data bits, are input into the binary symbol bypass decoding process, and the binary symbol bypass decoding process may output an updated ivlOffset variable and a binVal value obtained through decoding.

[00105] If bypassFlag is equal to 1, the bypass decoding process may be called. Fig. 6 shows a flow chart of the bypass decoding process in the prior art. As shown in Fig. 6, the ivlOffset variable may first be updated. That is, the IvlOffset value may be multiplied by 2, i.e., moved to the left by one bit. One bit obtained using read_bits(1) may be moved to ivlOffset, in particular, as follows.

[00106] ivlOffset =ivlOffset <<1;

[00107] ivlOffset =ivlOffset |read_bits(1).

[00108] The ivlOffset value can then be compared with the ivlCurrRange value. The subsequent operations can be as follows.

[00109] If ivlOffset is greater than or equal to ivlCurrRange, binVal may be set to 1 and ivlOffset equals ivlOffset minus ivlCurrRange.

[00110] Otherwise (if ivlOffset is less than ivlCurrRange), binVal may be set to 0.

[00111] During the entire process, the data in the bitstream must not cause ivlOffset to be greater than or equal to ivlCurrRange.

[00112] It should be further noted that in existing video coding standards, one or more transforms and skip transforms are usually supported for residuals. The transforms may include a discrete cosine transform (DCT), etc. A residual block that has undergone a transform (and quantization) usually has certain characteristics. For example, after some transforms (and quantizations), most of the energy is concentrated in the low-frequency region, so that the coefficients in the region in the upper left corner may be large; while the coefficients in the region in the lower right corner may be small and may even contain many coefficients with a value of 0. As the name suggests, in skip transform, no transform is performed. The skip transform coefficients and the transformed coefficients may be different in distribution and, therefore, may be coded using different coefficient coding methods. For example, in VVC, RRC may be applied to the transformed coefficient, and TSRC may be applied to the skip transform coefficient.

[00113] In a block subjected to a general transform such as a DCT, the coefficients located in locations from left to right may represent increasing frequencies, and the coefficients located in locations from top to bottom may represent increasing frequencies. The coefficients located in the upper left corner represent low frequencies. The coefficients located in the lower right corner represent high frequencies. Human eyes are more sensitive to low frequency information and are not particularly sensitive to high frequency information. Using such characteristics, some high frequency information may be processed more carefully or may be removed with less impact on vision. In some technologies, such as zero output, some high frequency information may be forced to be 0. For example, in a 64x64 block, any coefficient with an abscissa greater than or equal to 32 or an ordinate greater than or equal to 32 may be forced to be 0. This is just a simple example. The zero output range can be obtained by more complex methods, which are not described here. As shown in Fig. 7, the part in the upper left corner (i.e., the region containing a possible significant coefficient) may contain a significant coefficient (or a non-zero coefficient), and all coefficients in the part in the lower right corner (i.e., the zero output region) may be set to zero. Accordingly, subsequent encoding of any coefficient in the zero output region is not required, since this coefficient is exactly equal to 0.

[00114] In addition, after performing the transform (and quantization) on the residuals of a normal video, it is typical that large coefficients are distributed in the upper left corner, and many 0 coefficients are distributed in the lower right corner. Thus, when encoding coefficients, some methods are usually used, so that coefficients in a certain range in the upper left corner need to be encoded, and coefficients in a certain range in the lower right corner do not need to be encoded, i.e., they can be taken as 0 by default. In one method, when encoding coefficients of a block, the location of the last significant coefficient of the block in the scan order can be determined first. After the location is determined, all coefficients located below the location of the last significant coefficient in the scan order can be taken as 0, i.e., there is no need to encode them. Only the last significant coefficient and the coefficients located above the location of the last significant coefficient are subject to encoding. For example, in VVC, the location (LastSignificantCoeffX, LastSignificantCoeffY) of the last significant coefficient is determined based on last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix, and last_sig_coeff_y_suffix.

[00115] (a) last_sig_coeff_x_prefix specifies the prefix of the horizontal coordinate (or column position) of the last significant coefficient in scan order in the current block. Values of last_sig_coeff_x_prefix must be in the range from 0 to (log2ZoTbWidth<<1)-1, inclusive.

[00116] When last_sig_coeff_x_prefix is not present, it is assumed to be 0.

[00117] (b) last_sig_coeff_y_prefix specifies the prefix of the vertical coordinate (or row position) of the last significant coefficient in scan order in the current block. Values of last_sig_coeff_y_prefix must be in the range from 0 to (log2ZoTbHeight<<1) -1, inclusive.

[00118] When last_sig_coeff_y_prefix is not present, it is assumed to be 0.

[00119] (c) last_sig_coeff_x_suffix specifies the suffix of the horizontal coordinate (or column position) of the last significant coefficient in scan order in the current block. last_sig_coeff_x_suffix values must be in the range 0 to (1<< ( ( last_sig_coeff_x_prefix>>1)-1))-1, inclusive.

[00120] The horizontal coordinate (or column position) LastSignificantCoeffX of the last significant coefficient in the scan order in the current transform block can be obtained as follows.

[00121] If last_sig_coeff_x_suffix is not present, the following applies:

[00122] LastSignificantCoeffX = last_sig_coeff_x_prefix;

[00123] Otherwise (last_sig_coeff_x_suffix is present) the following applies:

[00124] LastSignificantCoeffX=(1<< ((last_sig_coeff_x_prefix>>1)-1))*(2+(last_sig_coeff_x_prefix&1)) + last_sig_coeff_x_suffix.

[00125] (b) last_sig_coeff_y_suffix specifies the suffix of the vertical coordinate (or row position) of the last significant coefficient in scan order in the current transform block. The values of last_sig_coeff_y_suffix must be in the range 0 to (1<< ((last_sig_coeff_y_prefix>>1)-1))-1, inclusive.

[00126] The vertical coordinate (or row position) LastSignificantCoeffY of the last significant coefficient in the scan order in the current transform block can be obtained as follows.

[00127] If last_sig_coeff_y_suffix is not present, the following applies:

[00128] LastSignificantCoeffY = last_sig_coeff_y_prefix;

[00129] Otherwise (last_sig_coeff_y_suffix is present) the following applies:

[00130] LastSignificantCoeffY = (1<< ((last_sig_coeff_y_prefix>>1)-1))*(2+(last_sig_coeff_y_prefix&1)) + last_sig_coeff_y_suffix.

[00131] Additionally, all of the last significant coefficient and the coefficient(s) located above the location of the last significant coefficient are to be coded. However, in normal video, even among these coefficients, there is a certain proportion of coefficients that are 0. In VVC, the sb_coded_flag flag (indicating whether the current sub-block is coded) can be used to determine whether the coefficients in the current sub-block should be coded. All coefficients in the current sub-block are taken as 0 if there is no need to code the coefficients in the current sub-block. Here, a sub-block can typically be n×n, such as 4×4.

[00132] sb_coded_flag[xS][yS] specifies the following for the subblock at location (xS, yS) in the current transform block, where the subblock is an array of transform coefficient levels:

[00133] When sb_coded_flag[xS][yS] is 0, all transform coefficient levels of the sub-block at location (xS, yS) in the current transform block are considered to be 0.

[00134] When sb_coded_flag[xS][yS] is not present, it is assumed to be 1.

[00135] In addition, when encoding coefficients, the compression efficiency can be improved by using the characteristics of the coefficients. For example, for a normal video, a certain proportion of coefficients among the coefficients to be encoded is 0. Thus, a syntax element can be used to indicate whether the current coefficient is 0. The syntax element can typically be a binary symbol. If the current coefficient is 0, it means that the encoding of the current coefficient is complete. Otherwise, it is necessary to continue encoding the current coefficient. As another example, for a normal video, the absolute values of a certain proportion of coefficients among the significant coefficients (i.e., non-zero coefficients) can be 1. Thus, a syntax element can be used to indicate whether the absolute value of the current coefficient is greater than 1. The syntax element can typically be a binary symbol. If the absolute value of the current coefficient does not exceed 1, it means that the encoding of the current coefficient is complete. Otherwise, it is necessary to continue encoding the current coefficient. For example, the syntactic elements involved in VVC are as follows.

[00136] sig_coeff_flag[xC][yC] indicates for the transform coefficient location (xC, yC) in the current transform block whether the corresponding transform coefficient level at the location (xC, yC) is non-zero, as shown below.

[00137] If sig_coeff_flag[xC][yC] is 0, the transform coefficient level at location (xC, yC) is set to 0.

[00138] Otherwise (sig_coeff_flag[xC][yC] is 1), the transform coefficient level at location (xC, yC) has a non-zero value.

[00139] When sig_coeff_flag[xC][yC] is not present, it is calculated as follows.

[00140] If transform_skip_flag[x0][y0][cIdx] is 0 or sh_ts_residual_coding_disabled_flag is 1, the following applies:

If (xC, yC) is the last significant location (LastSignificantCoeffX, LastSignificantCoeffY) in scan order or all of the following conditions are true, sig_coeff_flag[xC][yC] is considered to be 1:

(xC&((1<<log2SbW)-1), yC& ((1<<log2SbH)-1)) is equal to (0, 0),

inferSbDcSigCoeffFlag is 1, and

sb_coded_flag[xS][yS] is 1;

Otherwise, sig_coeff_flag[xC][yC] is considered equal to 0;

[00141] Otherwise (transform_skip_flag[x0][y0][cIdx] is 1 and sh_ts_residual_coding_disabled_flag is 0), the following applies:

If all the following conditions are true, sig_coeff_flag[xC][yC] is considered to be equal to 1:

(xC&((1<<log2SbW)-1), yC&((1<<log2SbH)-1)) equals ((1<<log2SbW)-1, (1<<log2SbH)-1),

inferSbSigCoeffFlag is 1, and

sb_coded_flag[xS][yS] is 1;

Otherwise, sig_coeff_flag[xC][yC] is considered equal to 0.

[00142] abs_level_gtx_flag[n][j] indicates whether the absolute value of the conversion factor (at scan position n) is greater than (j<<1)+1. When abs_level_gtx_flag[n][j] is not present, it is considered to be 0.

[00143] Thus, if the encoding of the current coefficient has not yet been performed after processing the above flags (also called syntax elements), then the remaining value, such as abs_remainder in VVC, of the absolute value of the coefficient must be encoded.

[00144] abs_remainder[n] is the remaining absolute value of the transform coefficient level that is encoded by the Golomb-Rice code at scan position n. When abs_remainder[n] is not present, it is considered to be 0.

[00145] Additionally, in VVC, syntax elements such as sig_coeff_flag, abs_level_gtx_flag, etc. may be encoded in the context mode, and abs_remainder may be encoded in the bypass mode. As mentioned above, context-oriented coding is more complex than bypass coding, that is, intuitively speaking, it requires more processing time. Using too much context-oriented coding may affect the decoding speed if a large number of coefficients need to be encoded. Therefore, the number of syntax elements to be encoded in the context mode may be limited. For example, once the number of binary symbols to be encoded in the context mode exceeds a threshold, subsequent coefficients may be forced to be encoded in the bypass mode, such as dec_abs_level in VVC.

[00146] dec_abs_level[n] is an intermediate value that is encoded by the Golomb-Rice code at scan position n. ZeroPos[n] is obtained in the process of analyzing dec_abs_level[n]. The absolute value AbsLevel[xC][yC] of the transformation coefficient level at location (xC, yC) can be obtained as follows.

[00147] If dec_abs_level[n] is not present or is equal to ZeroPos[n], AbsLevel[xC][yC] is set to 0.

[00148] Otherwise, if dec_abs_level[n] is less than ZeroPos[n], AbsLevel[xC][yC] is set to dec_abs_level[n]+1.

[00149] Otherwise (dec_abs_level[n] is greater than ZeroPos[n]), AbsLevel[xC][yC] is set equal to dec_abs_level[n].

[00150] All of the above refers to the absolute value of the coefficient. The sign of the significant coefficient can be determined using the coefficient sign flag coeff_sign_flag or some cgjcj,j gjkextybz sign flag. coeff_sign_flag[n] specifies the sign of the transform coefficient level for scan position n as follows.

[00151] If coeff_sign_flag[n] is 0, then the corresponding conversion coefficient level has a positive value.

[00152] Otherwise (coeff_sign_flag[n] is 1), the corresponding conversion coefficient level has a negative value.

[00153] When coeff_sign_flag[n] is not present, it is assumed to be 0. In this case, the value of CoeffSignLevel[xC][yC] specifies the sign of the transform coefficient level at location (xC, yC) as follows.

[00154] If CoeffSignLevel[xC][yC] is 0, then the corresponding transformation coefficient level is zero.

[00155] Otherwise, if CoeffSignLevel[xC][yC] is 1, the corresponding transformation coefficient level has a positive value.

[00156] Otherwise (CoeffSignLevel[xC][yC] is -1), the corresponding transformation coefficient level has a negative value.

[00157] It should be further noted that CoeffSignLevel[xC][yC] can also be obtained in another way, which is not described here.

[00158] In addition, the par_level_flag of the coefficient level parity may be additionally used in VVC. According to the flag, the parity of the current coefficient level can be known, which can be used in determining the value of the current coefficient level and dependent quantization.

[00159] par_level_flag[n] specifies the parity of the transform gain level at scan position n. If par_level_flag[n] is not present, it is assumed to be 0.

[00160] In addition, to determine the parity of the level of the transform coefficient, par_level_flag may be further used to determine, together with abs_level_gtx_flag and abs_remainder etc., the magnitude of the coefficient.

[00161] Here, since a context mode must be selected, used, and updated in context-oriented encoding, and no context mode must be selected, used, and updated in bypass encoding, a common practice is to arrange the syntax elements to be encoded by context-oriented encoding together and arrange the syntax elements to be encoded by bypass encoding in a certain range. This is more convenient for the hardware design. For example, the syntax elements to be encoded by context-oriented encoding in one block are first processed, and then the syntax elements to be encoded by bypass encoding are processed. The syntax elements to be encoded by context-oriented encoding in the current block may be further divided into multiple groups. The syntax elements to be encoded by bypass mode in one block may be further divided into multiple groups.

[00162] In a specific example, the specific RRC syntax is as shown in Table 1.

Table 1

[00163] The AbsLevel[xC][yC] array denotes an array of absolute values of the transform coefficients of the current transform block. The AbsLevelPass1[xC][yC] array denotes an array of partially reconstructed absolute values of the transform coefficients of the current transform block. The array indices xC and yC denote the location of (xC, yC) in the current transform block.

[00164] Some block size information, such as the logarithms log2ZoTbWidth and log2ZoTbHeight of the zero-output block size, must be determined after the stream enters the residual_coding(x0, y0, log2TbWidth, log2TbHeight, cIdx) function. A coefficient with an abscissa in the range [0, (1<<log2ZoTbWidth) - 1] and an ordinate in the range [0, (1<<log2ZoTbHeight) - 1] can be a significant coefficient. Here, (1<<log2ZoTbWidth) can denote the width of the zero-output transform block, and (1<< log2ZoTbHeight) can denote the height of the zero-output transform block. Then, the location of the last significant coefficient may be determined according to last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix and last_sig_coeff_y_suffix, etc. The coefficient located above the last significant coefficient in the scan order may be the significant coefficient. Then, the value of remBinsPass1 may be determined using the formula remBinsPass1=((1<<(log2TbWidth+log2TbHeight)) ×7) >>2. remBinsPass1 may indicate the number of syntax elements to be encoded by context-aware encoding (i.e., the number of syntax elements encoded based on the context mode) in the current block. It is understood that, in embodiments of the present invention, remBinsPass1 may refer to the remaining binaries of inpass1, i.e., the number of remaining binaries in the first round. The coefficients located above the last significant coefficient in the scan order need to be coded. For the sub-blocks containing these coefficients, it can in turn be determined whether each sub-block needs to be coded as the current sub-block. If the current sub-block needs to be coded, in RRC, the syntax elements to be coded by context-aware coding in the sub-block may be placed in the first round, and the syntax elements to be coded by bypass coding (i.e., the syntax elements coded based on the bypass mode) may be placed after the first round. For each coefficient, up to 4 syntax elements to be coded by context-aware coding may need to be processed, i.e., 1 sig_coeff_flag, 2 abs_level_gtx_flags, and 1 par_level_flag. In the first round, 1 can be subtracted from remBinsPass1 every time one syntactic element to be encoded by context-aware encoding is processed. If the coefficient is large enough, the remaining value, i.e. abs_remainder, needs to be further processed after several syntactic elements to be encoded by context-aware encoding have been processed in the first round. Otherwise, if remBinsPass1 is small enough (not corresponding to remBinsPass1>=4), the first round can terminate. The remaining coefficients can be processed directly using the bypass mode, i.e. dec_abs_level.

[00165] In another specific example, the specific syntax of TSRC is shown in Table 2.

Table 2

[00166] Some information about the block size must be determined after the stream has entered the residual_ts_coding(x0, y0, log2TbWidth, log2TbHeight, cIdx) function. Then, the RemCcbs value can be determined using the formula RemCcbs=((1<<(log2TbWidth+log2TbHeight)) ×7) >>2. RemCcbs may indicate the number of syntax elements to be encoded by context-aware encoding in the current block. It is understood that in embodiments of the present invention, RemCcbs may refer to the remaining binaries with context-aware encoding, i.e., the number of remaining binary symbols to be encoded by context-aware encoding. For each sub-block, it may be determined whether the sub-block needs to be encoded as the current sub-block. If the current sub-block is to be coded, in TSRC (unlike RRC) the syntax elements to be coded by context-aware encoding in the sub-block may be placed in two rounds. For each coefficient, up to 4 syntax elements to be coded by context-aware encoding may need to be processed in each of the first round and the second round. The syntax elements to be coded by bypass encoding may be placed after two rounds. In the first round and in the second round, 1 may be subtracted from remBinsPass1 every time one syntax element to be coded by context-aware encoding is processed. If the coefficient is large enough, the remaining value, i.e., abs_remainder, needs to be further processed after several syntax elements to be coded by context-aware encoding have been processed in the first round and in the second round. Otherwise, if remBinsPass1 is small enough (not equal to remBinsPass1>=4), the first two rounds can terminate. The remaining odds can be processed directly using the bypass mode, where it is still abs_remainder.

[00167] In brief, in the related art, a conventional video at present, such as a consumer video, can be compressed with excellent compression efficiency using an existing coefficient coding method. Typically, a consumer video may require a bit depth of 8 bits or 10 bits per pixel. In general, the bit rate of a consumer video is not too high and is usually several megabytes per second (MB/s) or less. However, videos related to some applications require a higher bit depth per pixel, such as a bit depth of 12 bits, 14 bits, 16 bits or more per pixel. A higher bit depth can generally result in a larger coefficient and a larger number of significant coefficients, thereby providing a higher bit rate. Videos related to some applications require higher quality. Higher quality can generally also result in a larger coefficient and a larger number of significant coefficients, thereby providing a higher bit rate. A higher bit rate may place higher demands on computing power, such as bandwidth, of the decoder.

[00168] In general, compared with the case of a low bit depth, low quality, low bit rate video (normal video), a high bit depth, high quality, high bit rate video (triple high definition video) requires more coefficients to be encoded and decoded, and these coefficients are larger. For example, there are many more coefficients to be encoded and decoded in a block in a triple high definition video compared to the number of coefficients to be encoded and decoded in a block of the same size in a normal video. This is because many coefficients in a block of a normal video all become 0 after being subjected to prediction, transformation, and quantization, while many coefficients in a block of a triple high definition video may still be non-zero after being subjected to prediction, transformation, and quantization. A large proportion of coefficients to be coded among the coefficients predicted, transformed, and quantized in a block of a normal video may be 0. Therefore, it may be very efficient to determine whether a region of coefficients needs to be coded using the location (LastSignificantCoeffX, LastSignificantCoeffY) of the last significant coefficient. Even a large proportion of coefficients located above the location of the last significant coefficient may still be 0. Therefore, it may be very efficient to further determine whether the current sub-block needs to be coded using the flag sb_coded_flag indicating whether the sub-block needs to be coded. However, when there are many significant coefficients in the current block, or even most or all of the coefficients are significant (i.e., non-zero), using the location of the last significant coefficient and the flag indicating whether the sub-block needs to be coded will not exclude too many significant coefficients. Moreover, providing the location of a significant coefficient and the flag indicating whether the sub-block needs to be coded, etc. into a bit stream may require a certain amount of resource consumption, which leads to irrational use.

[00169] In another aspect, the location of the last significant coefficient and the flag indicating whether the sub-block should be encoded, etc., may all be encoded in a context-oriented mode. Context-oriented coding is more complex than bypass coding, and processing this information may further impact the throughput and speed of encoding and decoding of software and hardware.

[00170] In another aspect, at present, a method for encoding the location (LastSignificantCoeffX, LastSignificantCoeffY) of the last significant coefficient is to encode the coordinates of the location of the last significant coefficient. In a normal video, since most of the significant coefficients are concentrated in the upper left corner, and the coefficients in a large area in the lower right corner are 0, the values of LastSignificantCoeffX and LastSignificantCoeffY may generally be small. In a triple high definition video, many significant coefficients may also appear in the lower right corner, which generally results in large values of LastSignificantCoeffX and LastSignificantCoeffY, thereby resulting in greater resource consumption in the bitstream due to encoding large values in the bitstream. In addition, another possibility is to apply the method in the case of lossless compression. Since quantization is not allowed in lossless compression, there may generally be many coefficients, and the coefficients may have large values. In this case, using the existing solution may result in higher resource consumption, irrational use, and reduced compression efficiency.

[00171] In embodiments of the present invention, a decoding method is provided. Identification information about a component of a current slice and information about the coordinates of the last significant coefficient of a current block corresponding to the component of the current slice are determined by analyzing a bit stream. When the identification information about the component indicates that a reversal of the location of the last significant coefficient is applied to the component of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to the information about the coordinates of the last significant coefficient. The coefficients of the current block are determined by decoding all coefficients located above the location of the last significant coefficient in a given scanning order.

[00172] In embodiments of the present invention, an encoding method is further provided. Identification information about a component of a current slice and the location of the last significant coefficient of a current block corresponding to the component of the current slice are determined. Information about the coordinates of the last significant coefficient of the current block is determined according to the identification information about the component and the location of the last significant coefficient. All coefficients located above the location of the last significant coefficient are encoded in a given scanning order. The bit information obtained by encoding, the identification information about the component and the coordinate information of the last significant coefficient are provided in a bitstream.

[00173] Thus, in the scenario of encoding and decoding video with a high bit depth, high bit rate, high quality or lossless, a reasonable acquisition mode of the last significant coefficient is set according to the distribution law of the significant coefficients, thereby reducing the resource consumption caused by coding in the bit stream and improving the compression efficiency. In addition, since the significant coefficients of the corresponding color components may differ in the distribution law, it is possible to use the corresponding component identification information to control the corresponding acquisition mode of the last significant coefficient for each color component, that is, to separately control whether to apply the reversal technology of the last significant coefficient to each color component, thereby further improving the compression efficiency.

[00174] Embodiments of the present invention are described further herein with reference to the drawings.

[00175] Fig. 8A is an exemplary block diagram of the composition of an encoder system according to embodiments of the present invention. As shown in Fig. 8A, the encoder 100 may comprise a partitioning unit 101, a prediction unit 102, a first adder 107, a transform unit 108, a quantization unit 109, an inverse quantization unit 110, an inverse transform unit 111, a second adder 112, a filtering unit 113, a decoded picture buffer (DPB) unit 114, and an entropy encoding unit 115. Here, the input data of the encoder 100 may be a video consisting of a sequence of images or a static image. The output data of the encoder 100 may be a bitstream (also called a bitstream) representing a compressed version of the input video.

[00176] The partitioning node 101 may partition the input video image into one or more coding tree nodes (CTUs). The partitioning node 101 may partition the image into one or more image blocks (also called tiles) and may further partition the tile into one or more packets. Here, a tile or packet may contain one or more full and/or partial CTUs. In addition, the partitioning node 101 may form one or more slices. A slice may contain one or more tiles in an image arranged in raster order, or one or more tiles covering a rectangular region in an image. The partitioning node 101 may further form one or more image fragments. An image fragment may contain one or more slices, tiles or packets.

[00177] During the encoding process by the encoder 100, the partitioning unit 101 may transmit the CTU to the prediction unit 102. In general, the prediction unit 102 may consist of a block partitioning unit 103, a motion estimation (ME) unit 104, a motion compensation (MC) unit 105, and an intra prediction unit 106. In particular, the block partitioning unit 103 further partitions the input CTU into smaller coding units (CUs) by iteratively using a quaternary tree-based partition, a binary tree-based partition, and a ternary tree-based partition. The prediction unit 102 may obtain an intermediate prediction block of the CU using the ME unit 104 and the MC unit 105. The intra prediction unit 106 may obtain the intra prediction block of the CU using various intra prediction modes, including a matrix-weighted intra prediction (MIP) mode. In an example, the motion estimation mode based on the optimization of the distortion level (RDO) can be called by the ME node 104 and the MC node 105 to obtain an intermediate prediction block. The method of determining the mode based on the RDO can be called by the intra prediction node 106 to obtain an intra prediction block.

[00178] The prediction node 102 may output a prediction block of a CU. The first adder 107 may calculate the difference between the CU in the output of the partition node 101 and the prediction block of the CU, i.e., the residual CU. The transform node 108 may read the residual CU and perform one or more transforms on the residual CU to obtain coefficients. The quantization node 109 may quantize the coefficients and output quantization coefficients (i.e., levels). The inverse quantization node 110 may scale the quantization coefficients to output reconstructed coefficients. The inverse transform node 111 may perform one or more inverse transforms corresponding to the one or more transforms in the transform node 108 and output the reconstructed residual. The second adder 112 may calculate the reconstructed CU by adding the reconstructed residual and the prediction block of the CU from the prediction node 102. The second adder 112 may further send the output of the second adder to the prediction unit 102 as a reference for the intra prediction. After all the CUs in the image or the sub-image have been reconstructed, the filtering unit 113 may perform loop filtering with respect to the reconstructed image or the sub-image. In this case, the filtering unit 113 may comprise one or more filters, such as a deblocking filter, a discrete adaptive offset (SAO) filter, an adaptive loop filter (ALF), a luminance mapping filter with chroma scaling (LMCS), and a neural network-based filter, etc. Alternatively, when the filtering unit 113 determines that a CU should not be used as a reference for encoding another CU, the filtering unit 113 may perform loop filtering with respect to one or more target pixels in the CU.

[00179] The output of the filtering unit 113 may be a decoded image or a sub-image. The decoded image or sub-image may be cached in the DPB unit 114. The DPB unit 114 may output the decoded image or sub-image based on the synchronization and control information. In this case, the image stored in the DPB unit 114 may be further used as a reference for the intermediate prediction or intra prediction performed by the prediction unit 102. Finally, the entropy encoding unit 115 may convert the parameter (such as a control parameter, additional information, etc.) required for decoding the image from the encoder 100 into a binary form and provide the binary form in a bit stream according to the syntax structure of each data node. That is, the encoder 100 outputs the final bit stream.

[00180] Additionally, the encoder 100 may have a first processor and a first memory device that records a computer program. When the first processor reads and runs the computer program, the encoder 100 may read an input video and generate a bit stream corresponding to the input video. Additionally, the encoder 100 may further be a computing device that has one or more chips. The nodes implemented as integrated circuits on a chip may have connection and data exchange functions similar to the corresponding nodes in Fig. 8A.

[00181] Fig. 8B is an exemplary block diagram of the composition of a decoder system according to embodiments of the present invention. As shown in Fig. 8B, a decoder 200 may comprise an analysis unit 201, a prediction unit 202, an inverse quantization unit 205, an inverse transform unit 206, an adder 207, a filtering unit 208, and a DPB unit 209. The input of the decoder 200 may be a bitstream representing a compressed version of a video or a still image. The output of the decoder 200 may be decoded video consisting of a sequence of images or a decoded still image.

[00182] The input bit stream of the decoder 200 may be a bit stream generated by the encoder 100. The analysis unit 201 may analyze the input bit stream and obtain a value of at least one syntax element from the input bit stream. The analysis unit 201 may convert a binary representation of the syntax element into a numeric value and send the numeric value to a node in the decoder 200 to obtain one or more decoded images. The analysis unit 201 may further analyze the input bit stream to obtain one or more syntax elements for displaying the decoded image.

[00183] During the decoding process by the decoder 200, the analysis node 201 may send a value of at least one syntax element and one or more variables to a node in the decoder 200. The one or more variables may be set or determined according to the value of at least one syntax element and configured to obtain one or more decoded images.

[00184] The prediction unit 202 may determine a prediction block of the current coding block (e.g., CU). The prediction unit 202 may comprise an MC unit 203 and an intra prediction unit 204. In particular, when it is indicated that an intermediate prediction mode is used to decode the current coding block, the prediction unit 202 may transmit corresponding parameters sent by the analysis unit 201 to the MC unit 203 to obtain the intermediate prediction block. When it is indicated that an intra prediction mode (including the MIP mode indicated by the MIP mode index) is used to decode the current coding block, the prediction unit 202 may transmit corresponding parameters from the analysis unit 201 to the intra prediction unit 204 to obtain the intra prediction block.

[00185] The inverse quantization node 205 may have the same function as the inverse quantization node 110 in the encoder 100. The inverse quantization node 205 may scale the quantization coefficients (i.e., levels) from the analysis node 201 to obtain reconstructed coefficients.

[00189] The inverse transform node 206 may have the same function as the inverse transform node 111 in the encoder 100. The inverse transform node 206 may perform one or more transforms (i.e., the inverse operations of one or more transforms performed by the inverse transform node 111 in the encoder 100) to obtain a reconstructed residual.

[00187] The adder 207 may perform addition of its input data (i.e., the prediction block from the prediction node 202 and the reconstructed residual from the inverse transform node 206) to obtain a reconstructed block of the current coding block. The reconstructed block may be further sent to the prediction node 202 as a reference for another block to be coded in the intra prediction mode.

[00188] After all CUs in the image or sub-image have been reconstructed, the filtering unit 208 may perform loop filtering on the reconstructed image or sub-image. The filtering unit 208 may comprise one or more filters, such as a deblocking filter, an SAO filter, an ALF filter, an LMCS filter, and a neural network filter, etc. Alternatively, when the filtering unit 208 determines that the reconstructed block is not used as a reference for decoding another block, the filtering unit 208 may perform loop filtering on one or more target pixels in the reconstructed block. In this case, the output of the filtering unit 208 may be a decoded image or sub-image. The decoded image or sub-image may be cached in the DPB unit 209. The DPB unit 209 may output the decoded image or sub-image according to the timing and control information. The image stored in the DPB node 209 may be further used as a reference for intermediate prediction or intra prediction performed by the prediction node 202.

[00189] Additionally, the decoder 200 may have a second processor and a second memory device that records a computer program. When the third processor reads and runs the computer program, the decoder 200 may read the input bit stream and generate decoded video corresponding to the input bit stream. Additionally, the decoder 200 may further be a computing device that has one or more chips. A node implemented as integrated circuits on a chip may have connection and data exchange functions similar to the corresponding nodes in Fig. 8B.

[00190] It should be further noted that, when embodiments of the present invention are applied to the encoder 100, the current block specifically refers to the current block to be encoded in the video image (or, for short, the coding block). When embodiments of the present invention are applied to the decoder 200, the current block specifically refers to the current block to be decoded in the video image (or, for short, the coding block).

[00191] In an embodiment of the present invention, Fig. 9 is a flow chart of a decoding method according to embodiments of the present invention. As shown in Fig. 9, the method may include the following operations S901 to S903.

[00192] In operation S901, identification information about a component of the current slice and information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice are determined by analyzing the bit stream.

[00193] It should be noted that the decoding method according to the embodiments of the present invention may specifically relate to a method for decoding a coefficient(s), which can be performed by a decoder. Based on the structure of the decoder 200, as shown in Fig. 8B, the decoding method is mainly performed by an analysis unit 201 in the decoder 200. The analysis unit 201 can obtain the value(s) of the associated identification information (or syntax element(s)) by performing decoding using the adaptive binary arithmetic coding mode based on the context model or the bypass mode, thereby determining the coefficients of the current block.

[00194] It should be further noted that, in general, coding in a video standard may include coding and decoding. Therefore, video coding may include a coding method performed on the encoder side and a decoding method performed on the decoder side. In embodiments of the present invention, a decoding method performed on the decoder side is described.

[00195] In general, for example, for a normal video, a method for decoding a coefficient(s) of a normal video is the same as an existing method in the prior art. However, in some cases, such as a scenario of encoding and decoding a video with a high bit depth, high quality, high bit rate or lossless compression, the embodiments of the present invention provide a method capable of modifying the mode of obtaining the location of the last significant coefficient.

[00196] In embodiments of the present invention, the identification information about the component of the current slice is a slice level flag. The identification information about the component indicates whether the reversal of the last significant coefficient is applied to the component of the current slice. If the reversal of the last significant coefficient is applied to the component of the current slice, this means that the reversal of the last significant coefficient is applied to the current block corresponding to the component of the current slice. If the reversal of the last significant coefficient is not applied to the component of the current slice, this means that the reversal of the last significant coefficient is not applied to the current block corresponding to the component of the current slice.

[00197] It is understood that the current sequence may include the current slice, and the current slice may include the current block. In some embodiments, before determining the identification information about the component of the current slice by analyzing the bitstream, the method may further include the following operations.

[00198] First identification information about a syntax element is determined by analyzing a bitstream.

[00199] The operation in which identification information about a component of the current slice is determined by analyzing a bitstream is performed when the first identification information about the syntax element indicates that reversal of the last significant coefficient is permitted for the current sequence.

[00200] In embodiments of the present invention, the method may further include the following step. If the value of the first identification information about the syntax element is a first value, it is determined that the first identification information about the syntax element indicates that reversal of the last significant coefficient is permitted for the current sequence. Alternatively, if the value of the first identification information about the syntax element is a second value, it is determined that the first identification information about the syntax element indicates that reversal of the last significant coefficient is prohibited for the current sequence.

[00201] It should be noted that the first value is different from the second value. The first value and the second value may be parametric or may be numeric. In particular, the first identification information about the syntax element may be a parameter provided in the profile, or may be a flag value, which is in no way limited in the embodiments of the present invention.

[00202] For example, the first identification information about the syntax element is a flag. In this case, the first value may be set to 1, and the second value may be set to 0. Alternatively, the first value may be set to "true" and the second value may be set to "false". Alternatively, the first value may be set to 0 and the second value may be set to 1. Alternatively, the first value may be set to the value "false" and the second value may be set to the value "true". Illustratively, for a flag, as a rule, the first value may be the value 1, and the second value may be the value 0, which, however, is in no way limited.

[00203] It should be further noted that the first identification information about the syntax element may be a sequence level flag, denoted as sps_reverse_last_sig_coeff_flag, for indicating whether reversal of the last significant coefficient is allowed for the current sequence. Thus, when obtaining through decoding that reversal of the last significant coefficient is allowed for the current sequence, the identification information about the component at the slice level may be further decoded to determine whether reversal of the last significant coefficient is applied to the component of the current slice.

[00204] Additionally, before obtaining the first identification information about the syntax element by decoding, in a possible embodiment, the method may further include the following operations.

[00205] Determining second identification information about the syntax element by analyzing the bitstream.

[00206] The operation in which the first identification information about the syntax element is determined by analyzing the bit stream is performed when the second identification information about the syntax element indicates that the extension version of the standard is applied to the current sequence.

[00207] Before obtaining the first identification information about the syntax element by decoding, in another possible embodiment, the method may further include the following operations.

[00208] Third identification information about the syntax element is determined by analyzing the bitstream.

[00209] The operation in which the first identification information about the syntax element is determined by analyzing the bit stream is performed when the third identification information about the syntax element indicates that the range extension is applied to the current sequence.

[00210] Before obtaining the first identification information about the syntax element by decoding, in another possible embodiment, the method may further include the following operations.

[00211] Determining second identification information about the syntax element by analyzing the bitstream.

[00212] The third identification information about the syntax element is determined by analyzing the bitstream when the second identification information about the syntax element indicates that the version of the extension of the standard is applied to the current sequence.

[00213] The operation in which the first identification information about the syntax element is determined by analyzing the bit stream is performed when the third identification information about the syntax element indicates that the range extension is applied to the current sequence.

[00214] It should be noted that both the second syntax element identification information and the third syntax element identification information are sequence-level flags. The second syntax element identification information is designated as sps_extension_flag to indicate whether a version of the standard extension is applied to the current sequence. The third syntax element identification information is designated as sps_range_extension_flag to indicate whether a range extension is applied to the current sequence.

[00215] That is, before obtaining the first identification information about the syntax element (sps_reverse_last_sig_coeff_flag) through decoding, the following operations may be performed. sps_extension_flag is obtained by analyzing the bitstream; and sps_reverse_last_sig_coeff_flag is obtained by decoding if sps_extension_flag indicates that the extension version of the standard is applied to the current sequence. Alternatively, sps_range_extension_flag is obtained by analyzing the bitstream; and sps_reverse_last_sig_coeff_flag is obtained by decoding if sps_range_extension_flag indicates that the range extension is applied to the current sequence. Alternatively, sps_extension_flag is obtained by analyzing the bitstream; sps_range_extension_flag is obtained by analyzing the bitstream if sps_extension_flag indicates that the extension version of the standard is applied to the current sequence; and sps_reverse_last_sig_coeff_flag is obtained by decoding if sps_range_extension_flag indicates that the range extension is applied to the current sequence. However, they are not limited in any way in the embodiments of the present invention.

[00216] Additionally, in some embodiments, the method may further include the following operation. If the value of the second identification information about the syntax element is the first value, it is determined that the second identification information about the syntax element indicates that the version of the extension of the standard is applied to the current sequence. Alternatively, if the value of the second identification information about the syntax element is the second value, it is determined that the second identification information about the syntax element indicates that the version of the extension of the standard is not applied to the current sequence.

[00217] Additionally, in some embodiments, the method may further include the following operation. If the value of the third identification information about the syntax element is the first value, it is determined that the third identification information about the syntax element indicates that the range extension is applied to the current sequence. Alternatively, if the value of the third identification information about the syntax element is the second value, it is determined that the third identification information about the syntax element indicates that the range extension is not applied to the current sequence.

[00218] It should be noted that the first value is different from the second value. The first value and the second value may be in parametric form or may be in numerical form. In a specific example, the first value may be set to 1 and the second value may be set to 0, which, however, is in no way limited.

[00219] It should be further noted that the second identification information about the syntax element is designated as sps_extension_flag. The third identification information about the syntax element is designated as sps_range_extension_flag. Accordingly, at the sequence level, if sps_extension_flag has the value 1, i.e., the extension version of the standard is applied to the current sequence, then sps_range_extension_flag must be decoded. If sps_range_extension_flag has the value 1, i.e., the range extension is applied to the current sequence, then sps_reverse_last_sig_coeff_flag must be decoded. If sps_reverse_last_sig_coeff_flag has the value 1, i.e., if reversal of the last significant coefficient is allowed for the current sequence, the slice-level component identification information must be further decoded to determine whether reversal of the last significant coefficient is applied to a component of the current slice.

[00220] In some embodiments, range extension is applied to the current sequence, which may include the current sequence having at least one of the following: high bit depth, high quality, high bit rate, high frame rate, or lossless compression.

[00221] That is, compared with conventional video, video according to embodiments of the present invention has characteristics of high bit depth, high quality, high bit rate, high frame rate, lossless compression, and/or the like.

[00222] Additionally, the first identification information about the syntax element, the second identification information about the syntax element, the third identification information about the syntax element, etc. may be sequence-level flags or even higher-level flags such as video usability information (VUI), supplemental optimization information (SEI), etc.

[00223] In a specific example, for the current video sequence, it is determined whether an extension version of the standard is applied to the current sequence using the second identification information about the syntax element (sps_extension_flag). In other words, it is determined whether the current sequence can be opened in an extension version of the standard, such as an extension version in VVC formulated for coding with a high bit depth and a high bit rate, etc. When sps_extension_flag has a value of 1, it is necessary to decode the first identification information about the syntax element (sps_reverse_last_sig_coeff_flag). Otherwise, it is not necessary to decode the first identification information about the syntax element (sps_reverse_last_sig_coeff_flag).

[00224] In another specific example, for the current video sequence, when sps_extension_flag has a value of 1, it is necessary to further decode a third identification information about the syntax element (sps_range_extension_flag) to determine whether a range extension is applied to the current sequence, such as a flag(s) with a high bit depth, high bit rate, high frame rate, lossless compression, and/or the like. For example, four cases are described respectively below in this document.

[00225] In a possible implementation, when the third identification information about the syntax element is identification information with a high bit depth, the method may further include the following operation. If the identification information with a high bit depth indicates that the current sequence has a high bit depth, it is determined that range extension is applied to the current sequence.

[00226] In another possible implementation, when the third identification information about the syntax element is identification information with a high bit rate, the method may further include the following operation. If the identification information with a high bit rate indicates that the current sequence has a high bit rate, it is determined that range extension is applied to the current sequence.

[00227] In another possible implementation, when the third identification information about the syntax element is high-quality identification information, the method may further include the following operation. If the high-quality identification information indicates that the current sequence has high quality, it is determined that the range extension is applied to the current sequence.

[00228] In another possible implementation, when the third identification information about the syntax element is identification information with lossless compression, the method may further include the following operation. If the identification information with lossless compression indicates that the current sequence has lossless compression (i.e. is losslessly compressed), it is determined that range extension is applied to the current sequence.

[00229] Illustratively, taking the sequence level as an example, the third identification information about the syntax element may further be high bit depth identification information (denoted as sps_high_bit_depth_flag) for indicating whether the current sequence is a high bit depth sequence; or alternatively may be high bit rate identification information (denoted as sps_high_bit_rate_flag) for indicating whether the current sequence is a high bit rate sequence; or alternatively may be other identification information for indicating high bit depth, high bit rate, high quality, or lossless compression, which is in no way limited in the embodiments of the present invention.

[00230] Additionally, in some embodiments, in operation S901, the operation in which information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice is determined by analyzing the bitstream may include the following operations.

[00231] Information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient are obtained by analyzing a bitstream.

[00232] The horizontal coordinate of the last significant coefficient is determined according to the information about the prefix of the horizontal coordinate of the last significant coefficient and the information about the suffix of the horizontal coordinate of the last significant coefficient.

[00233] The vertical coordinate of the last significant coefficient is determined according to the information about the prefix of the vertical coordinate of the last significant coefficient and the information about the suffix of the vertical coordinate of the last significant coefficient.

[00234] The information about the coordinates of the last significant coefficient of the current block may be determined according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00235] It should be noted that the information about the prefix of the horizontal coordinate of the last significant coefficient may be designated as last_sig_coeff_x_prefix, i.e., indicating the prefix of the horizontal coordinate (or column position) of the last significant coefficient in the given scan order in the current block. The information about the prefix of the vertical coordinate of the last significant coefficient may be designated as last_sig_coeff_y_prefix, i.e., indicating the prefix of the vertical coordinate (or row position) of the last significant coefficient in the given scan order in the current block. The information about the suffix of the horizontal coordinate of the last significant coefficient may be designated as last_sig_coeff_x_suffix, i.e., indicating the suffix of the horizontal coordinate (or column position) of the last significant coefficient in the given scan order in the current block. The vertical coordinate suffix information of the last significant coefficient can be denoted as last_sig_coeff_y_suffix, i.e., indicating the vertical coordinate suffix (or row position) of the last significant coefficient in the given scan order in the current block. That is, the coordinate information of the last significant coefficient can be determined based on last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix, and last_sig_coeff_y_suffix.

[00236] It should be further understood that last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may determine the abscissa (i.e., horizontal coordinate) of the last significant coefficient. last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may determine the ordinate (i.e., vertical coordinate) of the last significant coefficient, thereby obtaining information about the coordinates of the last significant coefficient.

[00237] In embodiments of the present invention, the identification information of the reversal of the last significant coefficient may be designated as reverse_last_sig_coeff_flag. The identification information of the reversal of the last significant coefficient may be at least one of sequence-level identification information, image-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited herein.

[00238] That is, reverse_last_sig_coeff_flag may be a sequence level flag or a higher level flag, or may be an image level flag or a slice level flag, or a block level flag, or another level flag. In addition, the block level flag may include an LCU level flag or a CTU level flag, or a CU level flag, or another block level flag, which is in no way limited in the embodiments of the present invention.

[00239] In embodiments of the present invention, the identification information of the reversal of the last significant coefficient at the sequence level may be designated as sps_reverse_last_sig_coeff_flag. The identification information of the reversal of the last significant coefficient at the slice level may be designated as sh_reverse_last_sig_coeff_flag.

[00240] It should be further noted that the identification information about the change of the location to the inverse of the last significant coefficient of the slice level may be further referred to as the identification information about the component of the current slice. In some embodiments, the method may further include the following operation.

[00241] When the value of the component identification information is the first value, it is determined that the component identification information indicates that a reversal of the last significant coefficient is applied to the component of the current slice.

[00242] Alternatively, when the value of the component identification information is the second value, it is determined that the component identification information indicates that the reversal of the last significant coefficient is not applied to the component of the current slice.

[00243] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric or may be numeric. In a specific example, the first value may be set to 1 and the second value may be set to 0, which, however, is in no way limited.

[00244] As an example, a first value equal to 1 and a second value equal to 0 are taken. If it is obtained through decoding that the value of the component identification information is 1, it can be determined that the component identification information indicates that the reversal of the last significant coefficient is applied to the component of the current slice. If it is obtained through decoding that the value of the component identification information is 0, it can be determined that the component identification information indicates that the reversal of the last significant coefficient is not applied to the component of the current slice.

[00245] In operation S902, in response to the identification information about the component indicating that a reversal of the location of the last significant coefficient is applied to the component of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to the coordinate information of the last significant coefficient.

[00246] In operation S903, the coefficients of the current block are determined by decoding all coefficients located above the location of the last significant coefficient in a specified scan order.

[00247] It should be noted that in the embodiments of the present invention, when the identification information about the component indicates that the reversal of the location of the last significant coefficient is applied to the component of the current slice, this means that the reversal of the location of the last significant coefficient is also applied to the current block corresponding to the component of the current slice. In this case, the coordinate information of the last significant coefficient of the current block can be defined as the horizontal distance and the vertical distance between the location of the last significant coefficient and the lower right corner of the current block.

[00248] In some embodiments, the operation of obtaining the location of the last significant coefficient of the current block by performing a calculation with respect to coordinate information of the last significant coefficient may include the following operations.

[00249] Defines the width and height of the current block.

[00250] The horizontal coordinate of the last significant coefficient is obtained by subtracting the horizontal distance between the location of the last significant coefficient and the lower right corner of the current block from the width of the current block.

[00251] The vertical coordinate of the last significant coefficient is obtained by subtracting the vertical distance between the location of the last significant coefficient and the lower right corner of the current block from the height of the current block.

[00252] The location of the last significant coefficient of the current block is determined according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00253] It should be noted that the coordinate information of the last significant coefficient is usually the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block. For a normal video, most of the significant coefficients are concentrated in the upper left corner, and the coefficients in a large area in the lower right corner are 0. However, for coding and decoding high bit depth, high quality, high bit rate video, many significant coefficients may also appear in the lower right corner, so the coordinate information of the last significant coefficient is of great importance. In this case, in order to save resource consumption, coordinate transformation (in particular, coordinate reversal, where after coordinate reversal, the coordinate information of the last significant coefficient is the horizontal distance and the vertical distance between the location of the last significant coefficient and the lower right corner of the current block) must be performed during coefficient coding. Accordingly, coordinate reversal must also be performed when decoding a coefficient. After re-executing the coordinate change to the reverse, the information about the coordinates of the last significant coefficient can be restored as a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block, while determining the location of the last significant coefficient for encoding all coefficients located above the location of the last significant coefficient in the current block, in a given scanning order.

[00254] It should be further noted that the current block corresponding to the component of the current slice may be a block to which the zero output transformation has not been performed or a block to which the zero output transformation has been performed. Taking the block to which the zero output transformation has been performed as an example, in this case, the width of the current block may be 1 << log2ZoTbWidth, and the height of the current block may be 1 << log2ZoTbHeight. Then, in the case where the identification information about the component indicates that the reversal of the location of the last significant coefficient is applied to the component of the current slice,

[00255] LastSignificantCoeffX= (1<<log2ZoTbWidth)-1-LastSignificantCoeffX;

[0056] LastSignificantCoeffY= (1<<log2ZoTbHeight)-1-LastSignificantCoeffY.

[00257] In this document, (LastSignificantCoeffX, LastSignificantCoeffY) on the right side of the formula may denote the coordinate information of the last significant coefficient obtained by decoding. (LastSignificantCoeffX, LastSignificantCoeffY) on the left side of the formula may denote the location of the last significant coefficient (which may also be regarded as the target coordinate information of the last significant coefficient).

[00258] Additionally, in some embodiments, the method may further include the following steps.

[00259] When the identification information about a component indicates that the reversal of the location of the last significant coefficient is not applied to the component of the current slice, the coordinate information of the last significant coefficient of the current block is determined as the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block.

[00260] The location of the last significant coefficient of the current block is determined according to the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block.

[00261] It should be noted that if the identification information about the component indicates that the reversal of the last significant coefficient is not applied to the component of the current slice, this also means that the reversal of the last significant coefficient is not applied to the current block corresponding to the component of the current slice. In this case, the coordinate information of the last significant coefficient obtained by decoding can be regarded as the target coordinate information of the last significant coefficient. In the embodiments of the present invention, the target coordinate information of the last significant coefficient is a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block.

[00262] Additionally, in some embodiments, the method may further include the following steps.

[00263] When the identification information about the component indicates that the reversal of the location of the last significant coefficient is not applied to the component of the current slice, the location of the last significant coefficient of the current block is determined directly according to the coordinate information of the last significant coefficient.

[00264] The coefficients of the current block are determined by decoding all coefficients located above the location of the last significant coefficient, in a given scan order.

[00265] It should be noted that the specified scanning order may be a diagonal scanning order, a zigzag scanning order, a horizontal scanning order, a vertical scanning order, a 4×4 sub-block scanning order, etc., which is in no way limited in the embodiments of the present invention.

[00266] It should be further noted that, after obtaining the identification information of the component of the current slice, if the identification information of the component of the current slice has a value of 1, i.e., a reversal of the location of the last significant coefficient is applied to the component of the current slice, then for the current block corresponding to the component of the current slice, after obtaining the coordinate information of the last significant coefficient by decoding, the location of the last significant coefficient of the current block is determined by performing a calculation with respect to the coordinate information of the last significant coefficient. Then, the coefficients of the current block are obtained by decoding all the coefficients above the location of the last significant coefficient in a given scanning order. If the identification information of the component of the current slice has a value of 0, i.e., the reversal of the location of the last significant coefficient is not applied to the component of the current slice, then for the current block corresponding to the component of the current slice, after obtaining the coordinate information of the last significant coefficient through decoding, the location of the last significant coefficient of the current block can be determined directly according to the coordinate information of the last significant coefficient. Then, the coefficients of the current block are obtained by decoding all the coefficients above the location of the last significant coefficient in a given scan order.

[00267] Thus, in some cases, such as encoding and decoding video with a high bit depth, high quality, high bit rate or lossless compression, during encoding coefficients, in the embodiments of the present invention, a method for modifying a mode of obtaining a location of the last significant coefficient is provided. That is, usually, the method of encoding and decoding coefficients is still the same as the existing method in the prior art. Usually, last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may be configured to encode the abscissa of the location of the last significant coefficient, i.e., the horizontal distance relative to the upper left corner of the current block; and last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be configured to encode the ordinate of the location of the last significant coefficient, i.e., the vertical distance relative to the upper left corner of the current block, as shown in Fig. 10A. When encoding and decoding video with high bit depth, high quality, high bit rate or lossless compression, the location of the last significant coefficient is usually close to the lower right corner of the region that includes all possible non-zero coefficients in the current block. In this case, last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may be configured to encode the horizontal distance between the location of the last significant coefficient and the lower right corner of the region that includes all possible non-zero coefficients in the current block, and last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be configured to encode the vertical distance between the location of the last significant coefficient and the lower right corner of the region that includes all possible non-zero coefficients in the current block, as shown in Fig. 10B. For example, if the region including all possible non-zero coefficients in the current block is a rectangular region defined by (0, 0) and ((1<<log2ZoTbWidth)-1, (1<<log2ZoTbHeight)-1), last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may be configured to encode the horizontal distance between the location of the last significant coefficient and ((1<<log2ZoTbWidth)-1, (1<<log2ZoTbHeight)-1) of the current block, and last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be configured to encode the vertical distance between the location of the last significant coefficient and ((1<<log2ZoTbWidth)-1, (1<<log2ZoTbHeight)-1) of the current block.

[00268] The modification of semantics is as follows.

[00269] The horizontal coordinate (or column position) LastSignificantCoeffX of the last significant coefficient in a given scan order in the current block can be obtained as follows.

[00270] If last_sig_coeff_x_suffix is not present, the following applies:

[00271] LastSignificantCoeffX= last_sig_coeff_x_prefix.

[00272] Otherwise (last_sig_coeff_x_suffix is present) the following applies:

[00273] LastSignificantCoeffX= (1<<((last_sig_coeff_x_prefix>>1)-1)) * (2+(last_sig_coeff_x_prefix&1)) + last_sig_coeff_x_suffix.

[00274] If reverse_last_sig_coeff_flag is 1, the following applies:

[00275] LastSignificantCoeffX = (1<<log2ZoTbWidth)-1-LastSignificantCoeffX.

[00276] The vertical coordinate (or row position) LastSignificantCoeffY of the last significant coefficient in scan order in the current block can be obtained as follows.

[00277] If last_sig_coeff_y_suffix is not present, the following applies:

[00278] LastSignificantCoeffY= last_sig_coeff_y_prefix.

[00279] Otherwise (last_sig_coeff_y_suffix is present):

[00280] LastSignificantCoeffY= (1<<((last_sig_coeff_y_prefix>>1)-1)) * (2+(last_sig_coeff_y_prefix&1)) + last_sig_coeff_y_suffix.

[00281] If reverse_last_sig_coeff_flag is 1, the following applies:

[00282] LastSignificantCoeffY= (1<<log2ZoTbHeight)-1-LastSignificantCoeffY.

[00283] In this document, reverse_last_sig_coeff_flag is a flag for reversing the location of the last significant coefficient, indicating whether the location of the last significant coefficient should be reversed. If reverse_last_sig_coeff_flag is set to 1, it indicates that the location of the last significant coefficient should be reversed. Otherwise, the flag indicates that the location of the last significant coefficient should not be reversed.

[00284] It should be further noted that reverse_last_sig_coeff_flag may be a sequence-level flag or a higher-level flag, or may be a picture-level flag or a slice-level flag or a block-level flag or another level flag. The block-level flag may include an LCU-level flag or a CTU-level flag or a CU-level flag or another block-level flag. Illustratively, the sequence-level reverse_last_sig_coeff_flag may be denoted as sps_reverse_last_sig_coeff_flag, and the slice-level reverse_last_sig_coeff_flag may be denoted as sh_reverse_last_sig_coeff_flag.

[00285] In addition, reverse_last_sig_coeff_flag may depend on some other flags such as high bit depth identification information, high bit rate identification information, or second identification information about a syntax element (sequence parameter set, SPS, extension flag sps_extension_flag), or the like. The SPS extension flag may be opened in an extension version of the standard, such as an extension version in VVC, formulated for high bit depth coding and high bit rate coding. That is, reverse_last_sig_coeff_flag needs to be decoded when the high bit depth identification information or the high bit rate identification information has a value of 1. Otherwise, reverse_last_sig_coeff_flag does not need to be decoded.

[00286] In a specific example, sequence level identification information sps_extension_flag, sps_range_extension_flag, and sps_reverse_last_sig_coeff_flag are assumed to exist. At the sequence level, if sps_extension_flag has a value of 1, sps_range_extension_flag must be decoded. If sps_range_extension_flag has a value of 1, sps_reverse_last_sig_coeff_flag must be decoded. In this document, sps_reverse_last_sig_coeff_flag is a flag for reversing the location of the last significant coefficient for the current sequence. If sps_reverse_last_sig_coeff_flag has a value of 1, it is determined that reversing the location of the last significant coefficient has been applied to a block in the current sequence. Otherwise (i.e., if sps_reverse_last_sig_coeff_flag is 0), it is determined that the reversal of the last significant coefficient is not applied to the block in the current sequence. reverse_last_sig_coeff_flag in the existing syntax table is modified as sps_reverse_last_sig_coeff_flag.

[00287] It is understood that sps_extension_flag can indicate whether a version of a standard extension is applied to the current sequence. sps_range_extension_flag can indicate whether a range extension (such as high bit depth, high bit rate, etc.) is applied to the current sequence.

[00288] In the implementation, the syntax element table is modified as follows (raw byte sequence payload of the sequence parameter set, RBSP, syntax), as shown in Table 3.

Table 3

[00289] In another implementation, the syntax element table is modified as follows (sequence parameter set range extension syntax), as shown in Table 4.

Table 4

[00290] Based on the syntax elements in Table 3 and Table 4, when the value of sps_extension_flag is 1, it means that the syntax elements sps_range_extension_flag and sps_extension_7bits are present in the SPS RBSP syntax structure; and when the value of sps_extension_flag is 0, it means that these syntax elements are not present in the SPS RBSP syntax structure.

[00291] In this document, if the value of sps_range_extension_flag is 1, it means that the sps_range_extension() syntax structure is present in the SPS RBSP syntax structure. If sps_range_extension_flag is not present, the value of sps_range_extension_flag is determined to be 0.

[00292] If the value of sps_reverse_last_sig_coeff_flag is 1, it means that the reversal of the last significant coefficient has been applied to the block in the current sequence. Otherwise (i.e., if the value of sps_reverse_last_sig_coeff_flag is 0), it means that the reversal of the last significant coefficient has not been applied to the block in the current sequence.

[00293] In another specific example, sequence level identification information sps_extension_flag, sps_range_extension_flag, and sps_reverse_last_sig_coeff_enabled_flag are assumed to exist. At the sequence level, if sps_extension_flag has a value of 1, sps_range_extension_flag must be decoded. If sps_range_extension_flag has a value of 1, sps_reverse_last_sig_coeff_enabled_flag must be decoded. In this document, sps_reverse_last_sig_coeff_enabled_flag is the enabling flag (technology) for reversing the location of the last significant coefficient for the current sequence. If sps_reverse_last_sig_coeff_enabled_flag has a value of 1, this means that reversing the location of the last significant coefficient is enabled for a block in the current sequence. Otherwise (i.e., if sps_reverse_last_sig_coeff_enabled_flag is 0), it means that last significant coefficient reversal is disabled for the block in the current sequence. If sps_reverse_last_sig_coeff_enabled_flag is not present, sps_reverse_last_sig_coeff_enabled_flag is specified to be 0. At the slice level, if sps_reverse_last_sig_coeff_enabled_flag is 1, sh_reverse_last_sig_coeff_flag needs to be decoded. In this document, sh_reverse_last_sig_coeff_flag represents the last significant coefficient reversal flag for the current slice. If sh_reverse_last_sig_coeff_flag is 1, it means that last significant coefficient reversal is applied to the block in the current slice. Otherwise (i.e., if sh_reverse_last_sig_coeff_flag is 0), it means that reversal of the last significant coefficient location is not applied to the block in the current slice. If sh_reverse_last_sig_coeff_flag is not present, sh_reverse_last_sig_coeff_flag is defined to have the value 0. reverse_last_sig_coeff_flag in the existing syntax table is modified as sh_reverse_last_sig_coeff_flag.

[00294] It should be noted that at the sequence level, the last significant coefficient reversal flag may mean "whether use of (something) is permitted/enabled". At the slice level, the last significant coefficient reversal flag may mean "determining whether... is applied/used".

[00295] In another implementation, the syntax element table is modified as follows (slice header syntax), as shown in Table 5.

Table 5

[00269] Based on the syntax element in Table 5, if the value of sps_reverse_last_sig_coeff_enabled_flag is 1, it means that reversing the location of the last significant coefficient is allowed for the block in the current sequence. Otherwise (i.e., if the value of sps_reverse_last_sig_coeff_enabled_flag is 0), it means that reversing the location of the last significant coefficient is prohibited for the block in the current sequence.

[00297] If the value of sh_reverse_last_sig_coeff_flag is 1, it means that the reversal of the last significant coefficient has been applied to the block in the current slice. Otherwise (i.e., if the value of sh_reverse_last_sig_coeff_flag is 0), it means that the reversal of the last significant coefficient has not been applied to the block in the current slice. If sh_reverse_last_sig_coeff_flag is not present, the value of sh_reverse_last_sig_coeff_flag is determined to be 0.

[00298] It is understood that for each of the color components of the current slice, the component identification information (i.e. sh_reverse_last_sig_coeff_flag) of the current slice may provide the ability to separately control whether to apply the reversal of the last significant coefficient to the color component.

[00299] In embodiments of the present invention, the component may comprise a first color component, a second color component, and a third color component.

[00300] In a particular example, the first color component is a luminance component. The second color component is the first chroma component. The third color component is the second chroma component. The luminance component may be denoted as Y. The first chroma component may be denoted as U(Cb). The second chroma component may be denoted as V(Cr).

[00301] In another specific example, the first color component is a red component, the second color component is a green component, and the third color component is a blue component. The red component may be designated as R. The green component may be designated as G. The blue component may be designated as B.

[00302] Additionally, in some embodiments, when the component comprises a first color component, a second color component, and a third color component, the method may further include the following operations.

[00303] It is determined whether the first color component, the second color component, and the third color component of the current slice share identification information about the component based on the relationship between the properties of the first color component, the second color component, and the third color component.

[00304] The number of parts of the component identification information of the current slice is determined according to the determination result. In this document, the number of parts of the component identification information is 1, 2, or 3.

[00305] In particular, the operation of determining the number of parts of the identification information about the component may include the following operation.

[00306] The number of parts of the component identification information of the current slice is determined to be 1 if one part of the component identification information is shared by the first color component, the second color component, and the third color component of the current slice.

[00307] Alternatively, the number of pieces of identification information about a component of the current slice is determined to be 2 if one piece of identification information about a component is shared by two of the first color component, the second color component, and the third color component of the current slice.

[00308] Alternatively, the number of parts of the component identification information of the current slice is determined to be 3 if each of the first color component, the second color component, and the third color component of the current slice has a separate part of the component identification information.

[00309] In embodiments of the present invention, on the one hand, the properties of the corresponding color components may differ. For example, the color components are R, G, B of the RGB video format or Y, U, V (Y, Cb, Cr) of the YUV video format, or color components of the video of another possible format. The YUV format may be a format such as YUV444, YUV422, YUV420. The human eye is more sensitive to a change in brightness than to a change in chrominance. Therefore, sometimes downsampling may be performed with respect to chrominance using a format such as YUV422, YUV420 and/or the like, and in general, the quantization step for chrominance may be larger than for luminance, which reduces the bit rate.

[00310] On the other hand, with some inter-component coding methods, the coding efficiency is improved due to the correlation between the components. For example, with the inter-component linear model (CCLM), in inter-component prediction, the chrominance component is predicted using the reconstructed luminance component and a linear model. With the CCLM, the prediction accuracy of the chrominance component can be improved, thereby reducing the residual chrominance component. In addition, in some other methods, information regarding the luminance component and one chrominance component is additionally used to predict the other component, thereby further improving the compression efficiency. In the inter-component adaptive loop filter (CCALF), the chrominance component is supplemented with some detail of the luminance component to improve the compression efficiency. The detail of the chrominance component can be supplemented with the luminance component, which allows for greater distortion in the residual coding.

[00311] Accordingly, since the properties of the corresponding color components are different and some inter-component methods are used, the corresponding color components may not always be compatible in the residual distribution. For example, when encoding and decoding video with a very high bit rate and very high quality requirements, the significant coefficients of different components may be the same in the distribution, for example, they are all located close to the lower right corner of the region including possible significant coefficients (i.e., non-zero coefficients). However, in some cases of encoding and decoding video with a not particularly high bit rate and not particularly high quality requirements, the significant coefficients of different components may be different in the distribution. For example, all the significant coefficients of the Y component are close to the lower right corner of the region including possible significant coefficients, and the significant coefficients of the U/V component are distributed only in the upper left corner. Alternatively, the significant coefficients of the U component are also close to the lower right corner, and the significant coefficients of the V component are distributed only in the upper left corner.

[00312] Therefore, in embodiments of the present invention, one or more pieces of component identification information may be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification/flag may control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification/flag may control application to a luma component, and another component identification/flag may control application to two chroma components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. For example, the three color components are R, G, and B in RGB format, or Y, Cb, and Cr (or Y, U, and V) in YUV format.

[00313] In a possible implementation, when the number of parts of the component identification information is 1, the operation in which the component identification information of the current slice is determined by analyzing the bitstream may include determining a first component identification information of the current slice by analyzing the bitstream.

[00314] Accordingly, the method may further include the following operation. If the value of the first component identification information is a first value, it is determined that the reversal of the last significant coefficient is applied to each of the first color component, the second color component, and the third color component of the current slice. Alternatively, if the value of the first component identification information is a second value, it is determined that the reversal of the last significant coefficient is not applied to any of the first color component, the second color component, and the third color component of the current slice.

[00315] In another possible implementation, when the number of pieces of component identification information is 2, the operation of determining component identification information of the current slice by analyzing the bitstream may include determining a second component identification information and a third component identification information of the current slice by analyzing the bitstream.

[00316] Accordingly, the method may further include the following operation. If the value of the second component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to each of the two color components of the first color component, the second color component, and the third color component of the current slice. Alternatively, if the value of the second component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to any of the two color components of the first color component, the second color component, and the third color component of the current slice.

[00317] If the value of the third component identification information is the first value, it is determined that the reversal of the location of the last significant coefficient is applied to another color component (i.e., the remaining color component) of the first color component, the second color component, and the third color component of the current slice, other than the two color components. Alternatively, if the value of the third component identification information is the second value, it is determined that the reversal of the location of the last significant coefficient is not applied to another color component of the first color component, the second color component, and the third color component of the current slice, other than the two color components.

[00318] In another possible implementation, when the number of pieces of component identification information is 3, the operation of determining component identification information of the current slice by analyzing the bitstream may include determining a fourth component identification information, a fifth component identification information, and a sixth component identification information of the current slice by analyzing the bitstream.

[00319] Accordingly, the method may further include the following operation. If the value of the fourth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the first color component of the current slice. Alternatively, if the value of the fourth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the first color component of the current slice.

[00320] If the value of the fifth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the second color component of the current slice. Alternatively, if the value of the fifth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the second color component of the current slice.

[00321] If the value of the sixth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the third color component of the current slice. Alternatively, if the value of the sixth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the third color component of the current slice.

[00322] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric or may be numeric. In a specific example, the first value may be set to 1 and the second value may be set to 0, which, however, is in no way limited.

[00323] It should be further noted that the component identification information in this case may be a slice level flag and may be designated as sh_reverse_last_sig_coeff_flag[cIdx]. In this document, cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may include sh_reverse_last_sig_coeff_flag[0], sh_reverse_last_sig_coeff_flag[1], and sh_reverse_last_sig_coeff_flag[2]. The fourth component identification information may be designated as sh_reverse_last_sig_coeff_flag[0] to indicate whether the reversal of the last significant coefficient location is applied to the current block corresponding to the first color component of the current slice. The fifth component identification information may be denoted as sh_reverse_last_sig_coeff_flag[1] to indicate whether the reversal of the last significant coefficient is applied to the current block corresponding to the second color component of the current slice. The sixth component identification information may be denoted as sh_reverse_last_sig_coeff_flag[2] to indicate whether the reversal of the last significant coefficient is applied to the current block corresponding to the third color component of the current slice.

[00324] In a specific example, a separate piece of component identification information is set for each of the three Y, U, and V color components to control. Supposedly, there is sequence level identification information sps_extension_flag, sps_range_extension_flag, and sps_reverse_last_sig_coeff_enabled_flag. At the sequence level, sps_extension_flag can be obtained by decoding. sps_range_extension_flag must be obtained by decoding if sps_extension_flag has a value of 1. sps_reverse_last_sig_coeff_enabled_flag must be obtained by decoding if sps_range_extension_flag has a value of 1. In this document, sps_reverse_last_sig_coeff_enabled_flag is the enabling flag of the reversal technology of the last significant coefficient for the current sequence. If sps_reverse_last_sig_coeff_enabled_flag is 1, it means that reversing the last significant coefficient is allowed for a block in the current sequence. Otherwise (i.e., if sps_reverse_last_sig_coeff_enabled_flag is 0), it means that reversing the last significant coefficient is prohibited for a block in the current sequence. If sps_reverse_last_sig_coeff_enabled_flag is not present, sps_reverse_last_sig_coeff_enabled_flag has the value 0. At the slice level, the component identification information (sh_reverse_last_sig_coeff_flag[0], sh_reverse_last_sig_coeff_flag[1], and sh_reverse_last_sig_coeff_flag[2]) must additionally be obtained through decoding if sps_reverse_last_sig_coeff_enabled_flag has the value 1. In this document, sh_reverse_last_sig_coeff_flag[cIdx] (where cIdx can have the value 0, 1, or 2) represents the flag of reversing the location of the last significant coefficient for the cIdx-th component of the current slice. If sh_reverse_last_sig_coeff_flag[cIdx] is 1, it means that the reversal of the last significant coefficient is applied to the cIdx-th component block of the current slice. Otherwise (i.e., if sh_reverse_last_sig_coeff_flag[cIdx] is 0), it means that the reversal of the last significant coefficient is not applied to the cIdx-th component block of the current slice. If sh_reverse_last_sig_coeff_flag[cIdx] is not present, sh_reverse_last_sig_coeff_flag[cIdx] is 0.

[00325] In a possible implementation for the YUV format, the 0th component corresponds to the Y component, the 1st component corresponds to the U(Cb) component, and the 2nd component corresponds to the V(Cr) component.

[00326] In another possible implementation for the RGB format, the 0th component corresponds to the R component, the 1st component corresponds to the G component, and the 2nd component corresponds to the B component.

[00327] Illustratively, taking the YUV format as an example, if sh_reverse_last_sig_coeff_flag[0] has a value of 1, it may be determined that the reversal of the last significant coefficient is applied to the first color component of the current slice (such as the Y component). If sh_reverse_last_sig_coeff_flag[1] has a value of 1, it may be determined that the reversal of the last significant coefficient is applied to the second color component of the current slice (such as the U component). If sh_reverse_last_sig_coeff_flag[2] has a value of 1, it may be determined that the reversal of the last significant coefficient is applied to the third color component of the current slice (such as the V component).

[00328] In the implementation, the syntax element table is modified as follows (the RBSP syntax of the sequence parameter set), as shown in Table 6.

Table 6

[00329] In another implementation, the syntax element table is modified as follows (sequence parameter set range extension syntax), as shown in Table 7.

Table 7

[00330] In another implementation, the syntax element table is modified as follows (slice header syntax), as shown in Table 8.

Table 8

[00331] In yet another implementation, there may additionally be another form of modification to the slice header syntax. The syntax element table is modified as follows (slice header syntax), as shown in Table 9.

Table 9

[00332] In this case, it may be envisaged that startComp is equal to 0 and numComps is equal to 3.

[00333] The modification of semantics is as follows.

[00334] The horizontal coordinate (or column position) LastSignificantCoeffX of the last significant coefficient in a given scan order in the current block can be obtained as follows.

[00335] If last_sig_coeff_x_suffix is not present, the following applies:

[00336] LastSignificantCoeffX= last_sig_coeff_x_prefix.

[00337] Otherwise (last_sig_coeff_x_suffix is present) the following applies:

[00338] LastSignificantCoeffX= (1<<((last_sig_coeff_x_prefix>>1)-1)) * (2+(last_sig_coeff_x_prefix&1)) + last_sig_coeff_x_suffix.

[00339] If sh_reverse_last_sig_coeff_flag[cIdx] is 1, the following applies:

[00340] LastSignificantCoeffX = (1<<log2ZoTbWidth)-1-LastSignificantCoeffX.

[00341] The vertical coordinate (or row position) LastSignificantCoeffY of the last significant coefficient in scan order in the current block can be obtained as follows.

[00342] If last_sig_coeff_y_suffix is not present, the following applies:

[00343] LastSignificantCoeffY= last_sig_coeff_y_prefix.

[00344] Otherwise (last_sig_coeff_y_suffix is present) the following applies:

[00345] LastSignificantCoeffY= (1<<((last_sig_coeff_y_prefix>>1)-1)) * (2+(last_sig_coeff_y_prefix&1)) + last_sig_coeff_y_suffix.

[00346] If sh_reverse_last_sig_coeff_flag[cIdx] is 1, the following applies:

[00347] LastSignificantCoeffY= (1<<log2ZoTbHeight)-1-LastSignificantCoeffY.

[00348] In this case, sh_reverse_last_sig_coeff_flag[cIdx] represents the flag of reversing the location of the last significant coefficient for the cIdx-th component of the current slice. cIdx can have the value 0, 1, or 2.

[00349] It should be further noted that when the third identification information about the syntax element indicates that the range extension is applied to the current sequence, all possible coefficients to be coded must be coded by default. That is, the location of the last significant coefficient is no longer used. Instead, all possible non-zero coefficients in the current block are scanned in a given scanning order. Therefore, in embodiments of the present invention, identification information about the resolved last coefficient may also be entered to determine whether the location of the last coefficient is applied to the current block.

[00350] In some embodiments, when the third identification information about the syntax element indicates that a range extension is applied to the current sequence, the method may further include the following operations.

[00351] Identification information about the last resolved coefficient of the current block is determined by analyzing the bit stream.

[00352] When the identification information about the last coefficient to be resolved indicates that the location of the last coefficient is applied to the current block, the coefficients of the current block are determined by decoding all coefficients located above the location of the last coefficient in a given scan order.

[00353] It should be noted that the identification information about the last coefficient to be enabled may be designated as default_last_coeff_enabled_flag. In the embodiments of the present invention, the identification information about the last coefficient to be enabled may be at least one of sequence-level identification information, image-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited herein.

[00354] That is, default_last_coeff_enabled_flag may be a sequence level flag or a higher level flag, or may be an image level flag or a slice level flag, or a block level flag, or another level flag. In addition, the block level flag may include an LCU level flag or a CTU level flag, or a CU level flag, or another block level flag, which is in no way limited in the embodiments of the present invention.

[00355] In some embodiments, the method may further include the following step.

[00356] If the value of the identification information of the last coefficient to be resolved is the first value, it is determined that the identification information of the last coefficient to be resolved indicates that the location of the last coefficient is applied to the current block.

[00357] Alternatively, if the value of the identification information of the last coefficient to be resolved is the second value, it is determined that the identification information of the last coefficient to be resolved indicates that the location of the last coefficient is not applied to the current block.

[00358] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric. The first value and the second value may be numeric. In a specific example, the first value may be set to 1 and the second value may be set to 0, which, however, is not limited in any way.

[00359] Accordingly, the first value is 1 and the second value is 0 as an example. If default_last_coeff_enabled_flag has a value of 1, it can be determined that default_last_coeff_enabled_flag indicates that the location of the last coefficient is applied to the current block. Alternatively, if default_last_coeff_enabled_flag has a value of 0, it can be determined that default_last_coeff_enabled_flag indicates that the location of the last coefficient is not applied to the current block.

[00360] When the location of the last coefficient is applied to the current block, the coefficients of the current block may be determined by decoding all coefficients located above the location of the last coefficient in a given scan order.

[00361] Additionally, when the location of the last coefficient is not applied to the current block, i.e. the value of the identification information about the resolved last coefficient is 0, in some embodiments, the method may further include the following operations.

[00362] Information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient are obtained by analyzing a bitstream.

[00363] The location of the last significant coefficient is determined according to information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient.

[00364] The coefficients of the current block are determined by decoding all coefficients located above the location of the last significant coefficient, in a given scan order.

[00365] It should be noted that if the location of the last coefficient is not applied to the current block, the location of the last significant coefficient needs to be obtained by decoding. Specifically, last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix, and last_sig_coeff_y_suffix are obtained by analyzing the bitstream. Then, the location of the last significant coefficient can be determined according to last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix, and last_sig_coeff_y_suffix. Otherwise, if the location of the last coefficient is applied to the current block, there is no longer a need to determine the location of the last significant coefficient, in which case there is no longer a need to obtain last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix, and last_sig_coeff_y_suffix through decoding.

[00366] It should be further noted that if the location of the last coefficient is applied to the current block, all coefficients located above the location of the last coefficient can be decoded in a given scan order. If the location of the last coefficient is not applied to the current block, all coefficients located above the location of the last significant coefficient can be decoded in a given scan order. In this case, the given scan order may be a diagonal scan order, a zigzag scan order, a horizontal scan order, a vertical scan order, a 4×4 sub-block scan order, etc., which is in no way limited in the embodiments of the present invention.

[00367] Additionally, in some embodiments, the location of the last coefficient is the lower right corner of a matrix formed by all possible non-zero coefficients in the current block. Alternatively, the location of the last coefficient is the last location of all possible non-zero coefficients in a given scan order in the current block.

[00368] It should be noted that in embodiments of the present invention, the location of the last coefficient does not represent the location of the last significant coefficient. This is because the coefficient at the location of the last coefficient may be equal to 0, while the coefficient at the location of the last significant coefficient is certainly not equal to 0.

[00369] In a specific example, the method may further include the following operation. The location of the last significant coefficient is set as the location of the last coefficient.

[00370] That is, in embodiments of the present invention, the location of the last significant coefficient may still be used. In this case, the location of the last significant coefficient must be placed at the last location of all possible non-zero coefficients in a given scan order in the current block.

[00371] Additionally, the location of the last coefficient may be designated as (LastCoeffX, LastCoeffY), i.e., the last location of all possible non-zero coefficients in a given scan order in the current block. In some embodiments, the method may further include the following operations.

[00372] Determine the width and height of the transformation block obtained by performing a specified operation on the current block.

[00373] Calculates coordinate information of the lower right corner of the transformation block according to the width and height of the transformation block.

[00374] The location of the last coefficient is determined according to the coordinate information of the lower right corner of the transformation block.

[00375] In this case, the specified operation includes at least a zero output operation.

[00376] It should be noted that (LastCoeffX, LastCoeffY) may denote the coordinate information of the lower right corner of the transformation block obtained after the zero output. (LastCoeffX, LastCoeffY) can be obtained as follows.

[00377] LastCoeffX= (1<<log2ZoTbWidth)-1.

[00378] LastCoeffY= (1<<log2ZoTbHeight)-1.

[00379] Accordingly, the location of the last coefficient can be determined according to (LastCoeffX, LastCoeffY) if default_last_coeff_enabled_flag is set to 1.

[00380] In a specific example, the location of the last significant coefficient is still used. In this case, the location of the last significant coefficient may be placed at the last location of all possible non-zero coefficients in a given scan order in the current block. In some embodiments, the method may further include the following operation.

[00381] When the location of the last significant coefficient is set as the location of the last coefficient, the location of the last significant coefficient is determined according to coordinate information of the lower right corner of the transformation block.

[00382] That is, the location of the last significant coefficient can be denoted as (LastSignificantCoeffX, LastSignificantCoeffY). (LastSignificantCoeffX, LastSignificantCoeffY) can be obtained as follows.

[00383] LastSignificantCoeffX= (1 <<log2ZoTbWidth)-1.

[00384] LastSignificantCoeffY= (1 <<log2ZoTbHeight)-1.

[00385] In this document, (LastSignificantCoeffX, LastSignificantCoeffY) may denote the coordinate information of the lower right corner of the transform block obtained after zero output. The location of the last significant coefficient may be determined according to (LastSignificantCoeffX, LastSignificantCoeffY) if default_last_coeff_enabled_flag is set to 1.

[00386] Thus, in some cases, such as encoding and decoding video with high bit depth, high quality, high bit rate or lossless compression, all possible coefficients to be encoded must be encoded by default when encoding the coefficients. Usually, the method of encoding and decoding the coefficients is still the same as the existing method in the prior art. All possible coefficients to be encoded must be encoded by default, that is, the location of the last significant coefficient is no longer used, instead, all possible non-zero coefficients in the current block are scanned in a given scan order. In other words, the location of the last coefficient to be encoded is placed in the last location of all possible non-zero coefficients in a given scan order in the current block. This location usually refers to the lower right corner of the matrix formed by all possible non-zero coefficients in the current block. In this case, the location of the last coefficient to be encoded may be used instead of the location of the last significant coefficient. This is because the coefficient at the location of the last coefficient to be encoded may be 0, whereas the coefficient at the location of the last significant coefficient is certainly not 0.

[00387] In a specific example, the location of the last significant coefficient is still used. In this case, the location of the last significant coefficient may be placed at the last location of all possible non-zero coefficients in a given scan order in the current block.

[00388] Furthermore, the reason why we are talking about all possible non-zero coefficients in a given scan order in the current block is that some coefficients in a block may be taken as 0 by default using some methods (such as the zero output mentioned above in this document), except for the last significant coefficient.

[00389] The semantic modification is as follows in Table 10.

Table 10

[00390] In embodiments of the present invention, the condition may need to be met before decoding the information required for the last significant coefficient. That is, syntax elements such as last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_suffix, etc. are obtained by decoding if default_last_coeff_enabled_flag is not true (i.e., default_last_coeff_enabled_flag is 0). Syntax elements such as last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix and last_sig_coeff_y_suffix and similar syntax elements do not need to be obtained through decoding if default_last_coeff_enabled_flag is true (i.e. default_last_coeff_enabled_flag is 1).

[00391] In this case, default_last_coeff_enabled_flag may be a default last coefficient enable flag to indicate whether to use/apply the last coefficient by default. If default_last_coeff_enabled_flag has a value of 1, it means that the location of the default last coefficient is used/applied. That is, the location of the last coefficient to be coded is placed at the last location of all possible non-zero coefficients in the specified scan order in the current block. Otherwise, the flag indicates that the location of the default last coefficient is not used/applied.

[00392] The location of the default last coefficient (LastCoeffX, LastCoeffY) is the last location of all possible non-zero coefficients in the specified scan order in the current block if default_last_coeff_enabled_flag has a value of 1. All coefficients located above (LastCoeffX, LastCoeffY) must be scanned in the specified scan order. In embodiments of the present invention, (LastCoeffX, LastCoeffY) can be obtained as follows.

[00393] LastCoeffX= (1<<log2ZoTbWidth)-1.

[00394] LastCoeffY= (1<<log2ZoTbHeight)-1.

[00395] In this document, (LastCoeffX, LastCoeffY) represents the coordinate information of the lower right corner of the transformation block obtained after zero output.

[00396] In a specific example, the location of the last significant coefficient is still used. The location of the last significant coefficient is placed at the last location of all possible non-zero coefficients in a given scan order in the current block. In embodiments of the present invention, the location (LastSignificantCoeffX, LastSignificantCoeffY) of the last significant coefficient can be obtained as follows.

[00397] LastSignificantCoeffX= (1<<log2ZoTbWidth)-1.

[00398] LastSignificantCoeffY= (1<<log2ZoTbHeight)-1.

[00399] In this document, (LastSignificantCoeffX, LastSignificantCoeffY) represents the coordinate information of the lower right corner of the transformation block obtained after the zero output.

[00400] It should be further noted that default_last_coeff_enabled_flag may be a sequence-level flag or a higher-level flag, or may be a picture-level flag or a slice-level flag or a block-level flag or another level flag. The block-level flag may include an LCU-level flag or a CTU-level flag or a CU-level flag or another block-level flag.

[00401] In addition, default_last_coeff_enabled_flag may depend on some other flags, such as high bit depth identification information, high bit rate identification information, etc. That is, default_last_coeff_enabled_flag needs to be decoded when the high bit depth identification information or the high bit rate identification information has a value of 1. Otherwise, there is no need to decode default_last_coeff_enabled_flag.

[00402] In a specific example, taking the sequence level as an example, the sequence level flag sps_high_bit_depth_flag is supposed to indicate whether the current video sequence is a high bit depth sequence. If sps_high_bit_depth_flag is 1, it means that the current video sequence is a high bit depth sequence. Otherwise, the flag indicates that the current video sequence is not a high bit depth sequence. At the sequence level, sps_default_last_coeff_enabled_flag needs to be obtained through decoding if sps_high_bit_depth_flag is 1. In this case, sps_default_last_coeff_enabled_flag may be an enabling flag of the last default coefficient of the current sequence. If sps_default_last_coeff_enabled_flag is 1, it means that the last default coefficient is used in the block in the current sequence. Otherwise (i.e. if sps_default_last_coeff_enabled_flag is 0) it means that the default last coefficient is not used in the block in the current sequence. default_last_coeff_enabled_flag in the syntax table above can be modified as sps_default_last_coeff_enabled_flag.

[00403] In the implementation, the syntax element table is modified as follows (the RBSP syntax of the sequence parameter set), as shown in Table 11.

Table 11

[00404] In another specific example, taking the slice level as an example, the sequence level flag sps_high_bit_depth_flag is supposed to indicate whether the current video sequence is a high bit depth sequence. If sps_high_bit_depth_flag is 1, it means that the current video sequence is a high bit depth sequence. Otherwise, the flag indicates that the current video sequence is not a high bit depth sequence. At the slice level, sh_default_last_coeff_enabled_flag needs to be obtained through decoding if sps_high_bit_depth_flag is 1. In this case, sh_default_last_coeff_enabled_flag may be the enabling flag of the default last coefficient of the current slice. If sh_default_last_coeff_enabled_flag is 1, it means that the default last coefficient is used in the block in the current slice. Otherwise (i.e. if sh_default_last_coeff_enabled_flag is 0) it means that the default last coefficient is not used in the block in the current slice. default_last_coeff_enabled_flag in the syntax table above can be modified as sh_default_last_coeff_enabled_flag.

[00405] In the implementation, the syntax element table is modified as follows (slice header syntax), as shown in Table 12.

Table 12

[00406] In embodiments of the present invention, for each color component of the current slice, the identification information about the default enabled last coefficient (i.e., sh_default_last_coeff_enabled_flag) of the current slice may provide the ability to separately control whether to apply the default last coefficient to the color component.

[00407] In particular, the identification information about the default enabled last coefficient of the current slice may also be designated as sh_default_last_coeff_enabled_flag[cIdx]. In this document, cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may include sh_default_last_coeff_enabled_flag[0], sh_default_last_coeff_enabled_flag[1], and sh_default_last_coeff_enabled_flag[2]. sh_default_last_coeff_enabled_flag[0] may indicate whether the default last coefficient is applied to the current block corresponding to the first color component of the current slice. sh_default_last_coeff_enabled_flag[1] can specify whether the last default coefficient is applied to the current block corresponding to the second color component of the current slice. sh_default_last_coeff_enabled_flag[2] can specify whether the last default coefficient is applied to the current block corresponding to the third color component of the current slice.

[00408] In this case, in embodiments of the present invention, one or more pieces of component identification information may also be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control the application to the luminance component, and another component identification may control the application to two chroma components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. For example, the three color components are R, G, and B in RGB format, or Y, Cb, and Cr (or Y, U, and V) in YUV format.

[00409] Illustratively, taking the YUV format as an example, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. If sh_default_last_coeff_enabled_flag[0] has a value of 1, it may be determined that the last default coefficient is applied to the block corresponding to the first color component of the current slice (such as the Y component). If sh_default_last_coeff_enabled_flag[1] has a value of 1, it may be determined that the last default coefficient is applied to the block corresponding to the second color component of the current slice (such as the U component). If sh_default_last_coeff_enabled_flag[2] is set to 1, it can be specified that the default last coefficient is applied to the block corresponding to the third color component of the current slice (such as the V component).

[00410] It should be further noted that when the third identification information about the syntax element indicates that the range extension is applied to the current sequence, the scanned sub-blocks need to be coded by default. In this case, there is no need to provide sb_coded_flag in the bitstream, i.e., neither the encoder nor the decoder needs to process this flag, which thereby speeds up encoding and decoding. Therefore, embodiments of the present invention can further introduce identification information about the sub-block to be coded by default to determine whether the sub-block to be coded in the current block is decoded by default.

[00411] In some embodiments, when the third identification information about the syntax element indicates that a range extension is applied to the current sequence, the method may further include the following operations.

[00412] Identification information about the default coded sub-block of the current block is determined by analyzing the bitstream.

[00413] When the identification information about the default coded sub-block indicates that the sub-block to be decoded in the current block is coded by default, all coefficients in the sub-block to be decoded are decoded.

[00414] It should be noted that, if the identification information about the default coded sub-block indicates that the sub-block to be decoded in the current block is coded by default, it can be determined that the value of the identification information about the default coded sub-block is the first value, in which case all coefficients in the sub-block to be decoded need to be decoded.

[00415] It should be further noted that the identification information about the default coded sub-block may be designated as default_sb_coded_flag. In embodiments of the present invention, the identification information about the default coded sub-block is at least one of sequence-level identification information, picture-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited here.

[00416] That is, default_sb_coded_flag may be a sequence level flag or a higher level flag, or may be an image level flag or a slice level flag, or a block level flag, or another level flag. In addition, the block level flag may include an LCU level flag or a CTU level flag, or a CU level flag, or another block level flag, which is in no way limited in the embodiments of the present invention.

[00417] In some embodiments, the method may further include the following operation. If the value of the identification information about the default-coded sub-block is a first value, it is determined that the identification information about the default-coded sub-block indicates that the sub-block to be decoded in the current block is coded by default. Alternatively, if the value of the identification information about the default-coded sub-block is a second value, it is determined that the identification information about the default-coded sub-block indicates that the sub-block to be decoded in the current block is not coded by default.

[00418] It should be noted that the first value and the second value may be different. The first value and the second value may be parametric. The first value and the second value may be numeric. In particular, the first identification information about the syntax element may be a parameter provided in the profile, or may be a flag value, which is in no way limited in embodiments of the present invention.

[00419] For example, the first identification information about the syntax element is a flag. In this case, the first value may be set to 1, and the second value may be set to 0. Alternatively, the first value may be set to "true", and the second value may be set to "false". Alternatively, the first value may be set to 0, and the second value may be set to 1. Alternatively, the first value may be set to "false", and the second value may be set to "true", which is in no way limited here.

[00420] Thus, the first value equal to 1 and the second value equal to 0 are taken as an example. If default_sb_coded_flag has a value of 1, it may be determined that default_sb_coded_flag indicates that the sub-block to be decoded should be coded by default. Alternatively, if default_sb_coded_flag has a value of 0, it may be determined that default_sb_coded_flag indicates that the sub-block to be decoded should not be coded by default.

[00421] When the sub-block to be decoded is coded by default, default_sb_coded_flag has a value of 1, which means that sb_coded_flag has a value of 1, i.e. there is no need to decode sb_coded_flag, in this case, all coefficients in the sub-block to be decoded need to be decoded by default.

[00422] Additionally, when the sub-block to be decoded is not to be coded by default, i.e. default_sb_coded_flag has a value of 0, in some embodiments the method may further include the following operations.

[00423] Identification information about the coded sub-block for the sub-block to be decoded is determined by analyzing the bit stream.

[00424] All coefficients in a sub-block to be decoded are decoded when the value of the identification information about the sub-block to be coded is the first value.

[00425] It should be noted that, if a sub-block to be decoded is not to be coded by default, identification information about the sub-block to be coded needs to be obtained through decoding, and it is determined according to the identification information about the sub-block to be coded whether to decode all coefficients in the sub-block to be decoded.

[00426] The method may further include the following operation. It is determined that all coefficients in the sub-block to be decoded are decoded if the value of the identification information about the sub-block to be coded is the first value. Alternatively, it is determined that all coefficients in the sub-block to be decoded are equal to zero if the value of the identification information about the sub-block to be coded is the second value.

[00427] In embodiments of the present invention, the identification information about the sub-block to be coded may be designated as sb_coded_flag. As an example, a first value of 1 and a second value of 0 are taken. If sb_coded_flag has a value of 1, it may be determined that all coefficients in the sub-block to be decoded need to be decoded. Alternatively, if sb_coded_flag has a value of 0, it may be determined that no coefficient in the sub-block to be decoded needs to be decoded, in which case all coefficients in the sub-block to be decoded are zero.

[00428] Thus, in a certain situation, when encoding coefficients, the scanned sub-blocks must be encoded by default, or the scanned sub-blocks contain significant coefficients by default. Usually, the method of encoding and decoding the coefficients is still the same as the existing method in the prior art. A certain situation may be, for example, encoding and decoding video with a high bit depth, high quality, high bit rate or lossless compression. In this situation, there are many significant coefficients, and almost all of the scanned sub-blocks must be encoded, or almost all of the scanned sub-blocks contain significant coefficients. In this case, there is no need to provide sb_coded_flag in the bitstream. Thus, neither the encoder nor the decoder needs to process this flag, which thereby speeds up encoding and decoding. Removing the almost non-existent flag further improves the compression efficiency.

[00429] The semantic modification is as follows in Table 13.

Table 13

[00430] In this document, default_sb_coded_flag is a flag of the default coded sub-block. If default_sb_coded_flag has a value of 1, it may be determined that the value of sb_coded_flag[xS][yS] is 1, in which case there is no need to decode from the bitstream. Otherwise (if default_sb_coded_flag has a value of 0), sb_coded_flag[xS][yS] additionally needs to be decoded from the bitstream.

[00431] It should be further noted that default_sb_coded_flag may be a sequence level flag or a higher level flag, or may be a picture level flag or a slice level flag or a block level flag or another level flag. The block level flag may include an LCU level flag or a CTU level flag or a CU level flag or another block level flag.

[00432] In addition, default_sb_coded_flag may depend on some other flags, such as high bit depth identification information, high bit rate identification information, etc. That is, default_sb_coded_flag needs to be decoded when the high bit depth identification information or the high bit rate identification information has a value of 1. Otherwise, there is no need to decode default_sb_coded_flag.

[00433] In a specific example, taking the sequence level as an example, the sequence level flag sps_high_bit_depth_flag is supposed to indicate whether the current video sequence is a high bit depth sequence. If sps_high_bit_depth_flag is 1, it means that the current video sequence is a high bit depth sequence. Otherwise, the flag indicates that the current video sequence is not a high bit depth sequence. At the sequence level, sps_default_sb_coded_flag is to be obtained by decoding if sps_high_bit_depth_flag is 1. In this case, sps_default_sb_coded_flag is a flag of the default coded sub-block for the current sequence. If sps_default_sb_coded_flag is 1, it means that the sub-block of the block in the current sequence is coded by default. Otherwise (i.e., if sps_default_sb_coded_flag is 0), it means that the subblock of the block in the current sequence is not coded by default. default_sb_coded_flag in the syntax table above can be modified as sps_default_sb_coded_flag.

[00434] In the implementation, the syntax element table is modified as follows (the RBSP syntax of the sequence parameter set), as shown in Table 14.

Table 14

[00435] In another specific example, taking the slice level as an example, the sequence level flag sps_high_bit_depth_flag is supposed to indicate whether the current video sequence is a high bit depth sequence. If sps_high_bit_depth_flag has a value of 1, it means that the current video sequence is a high bit depth sequence. Otherwise, the flag indicates that the current video sequence is not a high bit depth sequence. At the slice level, sh_default_sb_coded_flag shall be obtained through decoding if sps_high_bit_depth_flag has a value of 1. In this case, sh_default_sb_coded_flag is a flag of the default coded sub-block for the current slice. If sh_default_sb_coded_flag has a value of 1, it means that the sub-block of the block in the current slice is coded by default. Otherwise (i.e., if sh_default_sb_coded_flag is 0), it means that the subblock of the block in the current slice is not encoded by default. default_sb_coded_flag in the syntax table above can be modified as sh_default_sb_coded_flag.

[00436] In the implementation, the syntax element table is modified as follows (slice header syntax), as shown in Table 15.

Table 15

[00437] It should be noted that the sequence level flag sps_high_bit_depth_flag may be a flag indicating whether the current sequence is a high bit depth sequence; or alternatively, may be replaced by sps_high_bit_rate_flag indicating whether the current sequence is a high bit rate sequence, or may even be replaced by another flag indicating high bit depth, high bit rate, high quality, or lossless encoding, etc., which is in no way limited here.

[00438] In embodiments of the present invention, for each color component of the current slice, the identification information about the default coded sub-block (i.e., sh_default_sb_coded_flag) of the current slice may provide the ability to separately control whether to apply the default coded sub-block to the color component.

[00439] In particular, the identification information about the default coded sub-block of the current slice may also be designated as sh_default_sb_coded_flag[cIdx]. cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may contain sh_default_sb_coded_flag[0], sh_default_sb_coded_flag[1], and sh_default_sb_coded_flag[2]. sh_default_sb_coded_flag[0] may indicate whether the sub-block of the current block corresponding to the first color component of the current slice is coded by default. sh_default_sb_coded_flag[1] may indicate whether the sub-block of the current block corresponding to the second color component of the current slice is coded by default. sh_default_sb_coded_flag[2] can specify whether the subblock of the current block corresponding to the third color component of the current slice is encoded by default.

[00440] In this case, in embodiments of the present invention, one or more pieces of component identification information may also be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control the application to the luminance component, and another component identification may control the application to two chroma components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. For example, the three color components are R, G, and B in RGB format, or Y, Cb, and Cr (or Y, U, and V) in YUV format.

[00441] Illustratively, taking the YUV format as an example, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. If sh_default_sb_coded_flag[0] has a value of 1, it may be determined that the sub-block of the block that corresponds to the first color component of the current slice (such as the Y component) is coded by default. If sh_default_sb_coded_flag[1] has a value of 1, it may be determined that the sub-block of the block that corresponds to the second color component of the current slice (such as the U component) is coded by default. If sh_default_sb_coded_flag[2] has a value of 1, it may be determined that the sub-block of the block that corresponds to the third color component of the current slice (such as the V component) is coded by default.

[00442] In short, for all color components in a video, one piece of identification information may be used to control all color components for using the method according to the embodiments of the present invention. Alternatively, different pieces of identification information may be used to separately control corresponding color components for using the method according to the embodiments of the present invention. Alternatively, two pieces of identification information may be used to control all color components for using the method according to the embodiments of the present invention. In other words, more than one piece of identification information may be used to control different color components for using the method according to the embodiments of the present invention. Herein, all color components may be R, G, and B of RGB video format, or Y, U, and V (Y, Cb, and Cr) of YUV video format, or the like.

[00443] In an embodiment, a decoding method performed by a decoder is provided. In the method, identification information about a component of a current slice and coordinate information of the last significant coefficient of a current block corresponding to the component of the current slice are determined by analyzing a bitstream. When the identification information about the component indicates that a reversal of the last significant coefficient is applied to the component of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to the coordinate information of the last significant coefficient. The coefficients of the current block are determined by decoding the coefficients located above the location of the last significant coefficient in a given scanning order. Thus, in a scenario of encoding and decoding video with a high bit depth, a high bit rate, high quality or lossless, a reasonable acquisition mode of the last significant coefficient is set according to a distribution law of significant coefficients, which thereby reduces resource consumption caused by encoding in a bitstream and improves compression efficiency. In addition, since the corresponding color components may be different in the distribution of significant coefficients, it is also possible to precisely control the corresponding mode of obtaining the last significant coefficient for each color component, i.e., separately controlling whether to apply the last significant coefficient reversal technology to each color component, thereby further improving the compression efficiency.

[00444] In another embodiment of the present invention, Fig. 11 is a flow chart of a coding method according to embodiments of the present invention. As shown in Fig. 11, the method includes the following steps S1101 to S1103.

[00445] In operation S1101, identification information about a component of the current slice and the location of the last significant coefficient of the current block corresponding to the component of the current slice are determined.

[00446] In operation S1102, information about the coordinates of the last significant coefficient of the current block is determined according to the identification information about the component and the location of the last significant coefficient.

[00447] In S1103, all coefficients located above the location of the last significant coefficient are encoded in a predetermined scanning order. Bit information obtained by encoding, identification information about a component, and information about the coordinates of the last significant coefficient are provided to a bit stream.

[0048] It should be noted that the encoding method according to the embodiments of the present invention may specifically relate to a method for encoding a coefficient(s), which may be performed by an encoder. Based on the structure of the encoder 100, as shown in Fig. 8A, the encoding method is mainly performed by an entropy encoding unit 115 of the encoder 100. The entropy encoding unit 115 may perform entropy encoding on the associated identification information (or syntax element(s)) using an adaptive binary arithmetic encoding mode based on a context model or a bypass mode, and may provide the entropy encoding result to a bitstream.

[00449] It should be further noted that, in general, coding in a video standard may include coding and decoding. Therefore, video coding may include a coding method performed on the encoder side and a decoding method performed on the decoder side. In embodiments of the present invention, a coding method performed on the encoder side is described.

[00450] In general, for example, for a normal video, a method for encoding a coefficient(s) of a normal video is the same as an existing method in the prior art. However, in some cases, such as encoding and decoding video with a high bit depth, high quality, high bit rate, or lossless compression, embodiments of the present invention provide a method capable of modifying a mode for obtaining the location of the last significant coefficient. In this case, embodiments of the present invention introduce identification information about a component for determining whether a change in the location of the last significant coefficient is applied to a component of the current slice.

[00451] In embodiments of the present invention, the component identification information may be a slice level flag. The component identification information may indicate whether the reversal of the last significant coefficient is applied to the component of the current slice. If the reversal of the last significant coefficient is applied to the component of the current slice, this means that the reversal of the last significant coefficient is applied to the current block corresponding to the component of the current slice. If the reversal of the last significant coefficient is not applied to the component of the current slice, this means that the reversal of the last significant coefficient is not applied to the current block corresponding to the component of the current slice.

[00452] It is understood that the current sequence may include the current slice, and the current slice may include the current block. In some embodiments, before determining the identification information about the component of the current slice, the method may further include the following operations.

[00453] Determine first identification information about a syntax element.

[00454] The operation of determining the identification of a component of the current slice is performed when the first identification information about the syntax element indicates that reversal of the location of the last significant coefficient is permitted for the current sequence.

[00455] In embodiments of the present invention, the operation of determining first identification information about a syntax element may include the following operation. If reversal of the last significant coefficient is permitted for the current sequence, the value of the first identification information about the syntax element is determined as a first value. Alternatively, if reversal of the last significant coefficient is prohibited for the current sequence, the value of the first identification information about the syntax element is determined as a second value.

[00456] The method may further include the following operation. The first identification information about the syntax element is provided in the bitstream.

[00457] It should be noted that the first value and the second value may be different. The first value and the second value may be parametric or may be numeric. In particular, the first identification information about the syntax element may be a parameter provided in the profile, or may be a flag value, which is in no way limited in embodiments of the present invention.

[00458] For example, the first identification information about the syntax element is a flag. In this case, the first value can be set to 1, and the second value can be set to 0. Alternatively, the first value can be set to "true" and the second value can be set to "false". Alternatively, the first value can be set to 0, and the second value can be set to 1. Alternatively, the first value can be set to the value "false" and the second value can be set to the value "true". Illustratively, for a flag, as a rule, the first value can be the value 1, and the second value can be the value 0, which, however, is in no way limited.

[00459] It should be further noted that the first identification information about the syntax element may be a sequence level flag, denoted as sps_reverse_last_sig_coeff_flag, for indicating whether reversal of the last significant coefficient is allowed for the current sequence. Accordingly, when it is determined that reversal of the last significant coefficient is allowed for the current sequence, identification information about the component at the slice level may be further determined to determine whether reversal of the last significant coefficient is applied to a component of the current slice.

[001] Additionally, prior to determining the first identification information about the syntax element, in a possible embodiment, the method may further include the following operations.

[002] Define second identification information about the syntax element.

[003] The first identification information about the syntax element is determined when the second identification information about the syntax element indicates that the extension version of the standard is applied to the current sequence.

[004] Before determining the first identification information about the syntax element, in another possible embodiment, the method may further include the following operations.

[005] Define third identification information about the syntax element.

[006] The first identification information about the syntax element is determined when the third identification information about the syntax element indicates that a range extension is applied to the current sequence.

[007] Before determining the first identification of the syntax element, in another possible embodiment, the method may further include the following operations.

[008] [00467] Specify second identification information about the syntax element.

[00468] A third identification information about a syntax element is determined when the second identification information about a syntax element indicates that a version of an extension of the standard is applied to the current sequence.

[00469] The first identification information about the syntax element is determined when the third identification information about the syntax element indicates that a range extension is applied to the current sequence.

[00470] It should be noted that both the second syntax element identification information and the third syntax element identification information are sequence-level flags. The second syntax element identification information may be designated as sps_extension_flag to indicate whether an extension version of the standard is applied to the current sequence. The third syntax element identification information may be designated as sps_range_extension_flag to indicate whether a range extension is applied to the current sequence.

[00471] That is, before determining the first syntax element identification information (sps_reverse_last_sig_coeff_flag), the following operations may be performed. Define sps_extension_flag; and define sps_reverse_last_sig_coeff_flag if sps_extension_flag indicates that the standard extension version is applied to the current sequence. Alternatively, define sps_range_extension_flag; and define sps_reverse_last_sig_coeff_flag if sps_range_extension_flag indicates that the range extension is applied to the current sequence. Alternatively, define sps_extension_flag; define sps_range_extension_flag if sps_extension_flag indicates that the standard extension version is applied to the current sequence; and sps_reverse_last_sig_coeff_flag is determined if sps_range_extension_flag indicates that range extension is applied to the current sequence, which, however, is in no way limited in the embodiments of the present invention.

[00472] In embodiments of the present invention, the operation of determining the second identification information about the syntax element may include the following operation. If the extension version of the standard is applied to the current sequence, the value of the second identification information about the syntax element is determined as the first value. Alternatively, if the extension version of the standard is not applied to the current sequence, the value of the second identification information about the syntax element may be determined as the second value.

[00473] The method may further include the following operation. The second identification information about the syntax element is provided in the bitstream.

[00474] In embodiments of the present invention, the operation of determining the third identification information about the syntax element may include the following operation. If the range extension is applied to the current sequence, the value of the third identification information about the syntax element is determined as a first value. Alternatively, if the range extension is not applied to the current sequence, the value of the third identification information about the syntax element is determined as a second value.

[00475] The method may further include the following operation. Third identification information about the syntax element is provided in the bitstream.

[00476] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric or may be numeric. In a specific example, the first value is set to 1 and the second value is set to 0, which, however, is not limited in any way.

[00477] It should be further noted that the second identification information about the syntax element may be designated as sps_extension_flag. The third identification information about the syntax element may be designated as sps_range_extension_flag. Accordingly, at the sequence level, if sps_extension_flag has a value of 1, i.e., the extension version of the standard is applied to the current sequence, then sps_range_extension_flag must be defined. If sps_range_extension_flag has a value of 1, i.e., the range extension is applied to the current sequence, then sps_reverse_last_sig_coeff_flag must be defined. If sps_reverse_last_sig_coeff_flag is set to 1, meaning that reversal of the last significant coefficient is allowed for the current sequence, it is necessary to additionally define the component identification information at the slice level to determine whether reversal of the last significant coefficient is applied to a component of the current slice.

[00478] In some embodiments, range extension is applied to the current sequence, which may include that the current sequence has at least one of the following: high bit depth, high quality, high bit rate, high frame rate, or lossless compression. For example, four cases are described below in this document, respectively.

[00479] In a possible implementation, when the third identification information about the syntax element is identification information with a high bit depth, the method may further include the following operation. If the identification information with a high bit depth indicates that the current sequence has a high bit depth, it is determined that range extension is applied to the current sequence.

[00480] In another possible implementation, when the third identification information about the syntax element is identification information with a high bit rate, the method may further include the following operation. If the identification information with a high bit rate indicates that the current sequence has a high bit rate, it is determined that range extension is applied to the current sequence.

[00481] In another possible implementation, when the third identification information about the syntax element is high-quality identification information, the method may further include the following operation. If the high-quality identification information indicates that the current sequence has high quality, it is determined that the range extension is applied to the current sequence.

[00482] In another possible implementation, when the third identification information about the syntax element is identification information with lossless compression, the method may further include the following operation. If the identification information with lossless compression indicates that the current sequence is losslessly compressed, it is determined that range extension is applied to the current sequence.

[00483] Illustratively, taking the sequence level as an example, the third identification information about the syntax element may further be high bit depth identification information (denoted as sps_high_bit_depth_flag) for indicating whether the current sequence is a high bit depth sequence; or alternatively may be high bit rate identification information (denoted as sps_high_bit_rate_flag) for indicating whether the current sequence is a high bit rate sequence; or alternatively may be other identification information for indicating high bit depth, high bit rate, high quality, or lossless compression, which is in no way limited in the embodiments of the present invention.

[00484] In embodiments of the present invention, the first identification information about the syntax element, the second identification information about the syntax element, the third identification information about the syntax element, and the like may be sequence-level flags or even higher-level flags such as video usability information (VUI), supplemental optimization information (SEI), and the like.

[00485] Additionally, the identification information about the reversal of the last significant coefficient may be designated as reverse_last_sig_coeff_flag. The identification information about the reversal of the last significant coefficient may be at least one of sequence-level identification information, image-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited here.

[00486] That is, reverse_last_sig_coeff_flag may be a sequence level flag or a higher level flag, or may be an image level flag or a slice level flag, or a block level flag, or another level flag. In addition, the block level flag may include an LCU level flag or a CTU level flag, or a CU level flag, or another block level flag, which is in no way limited in the embodiments of the present invention.

[00487] In embodiments of the present invention, the identification information of the reversal of the last significant coefficient at the sequence level may be denoted as sps_reverse_last_sig_coeff_flag, and the identification information of the reversal of the last significant coefficient at the slice level may be denoted as sh_reverse_last_sig_coeff_flag.

[00488] It should be further noted that the identification information about the change of the location to the inverse of the last significant coefficient of the slice level may be further referred to as the identification information about the component of the current slice. In some embodiments, the operation of determining the identification information about the component of the current slice may include the following operations.

[00489] If a reversal of the last significant coefficient is applied to a component of the current slice, the value of the identification information of the component is determined as the first value.

[00490] Alternatively, if the reversal of the last significant coefficient is not applied to the component of the current slice, the value of the identification information about the component is determined as the second value.

[00491] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric or may be numeric. In a specific example, the first value is set to 1 and the second value is set to 0, which, however, is in no way limited.

[00492] As an example, a first value of 1 and a second value of 0 are taken. If the reversal of the last significant coefficient is applied to a component of the current slice, i.e. the reversal of the last significant coefficient is applied to the current block corresponding to the component of the current slice, it may be determined that the value of the identification information about the component is 1. If the reversal of the last significant coefficient is not applied to a component of the current slice, i.e. the reversal of the last significant coefficient is not applied to the current block corresponding to the component of the current slice, it may also be determined that the value of the identification information about the component is 0.

[00493] Additionally, the location of the last significant coefficient of the current block corresponding to the component of the current slice includes a starting horizontal coordinate and a starting vertical coordinate of the last significant coefficient. When the starting horizontal coordinate and the starting vertical coordinate are a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block, respectively, the operation in which the coordinate information of the last significant coefficient of the current block is determined according to the identification information of the component and the location of the last significant coefficient may include the following operation.

[00494] If the component identification value is the first value, the coordinate information of the last significant coefficient is determined by performing a calculation with respect to the initial horizontal coordinate and the initial vertical coordinate of the last significant coefficient.

[00495] Alternatively, if the component identification value is the second value, the coordinate information of the last significant coefficient is determined directly according to the initial horizontal coordinate and the initial vertical coordinate of the last significant coefficient.

[00496] In other words, in some embodiments, the method may further include the following step.

[00497] If the component identification value is the first value, the coordinate information of the last significant coefficient is determined as the horizontal distance and the vertical distance between the location of the last significant coefficient and the lower right corner of the current block.

[00498] Alternatively, if the component identification value is the second value, the coordinate information of the last significant coefficient is determined as the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block.

[00499] That is, the coordinate information of the last significant coefficient is usually the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block. For a normal video, most of the significant coefficients are concentrated in the upper left corner, and the coefficients in a large area in the lower right corner are 0. However, for coding and decoding videos with a high bit depth, high quality, high bit rate, many significant coefficients may also appear in the lower right corner, so the coordinate information of the last significant coefficient is of great importance. In this case, in order to save resource consumption, coordinate transformation (in particular, coordinate reversal, where after coordinate reversal, the coordinate information of the last significant coefficient is the horizontal distance and the vertical distance between the location of the last significant coefficient and the lower right corner of the current block) must be performed during coefficient encoding. Accordingly, during subsequent decoding of the coefficients, coordinate reversal must also be performed in the decoder. After re-executing the coordinate reversal, the coordinate information of the last significant coefficient can be reconstructed as the horizontal distance and vertical distance between the location of the last significant coefficient and the upper-left corner of the current block, thereby determining the location of the last significant coefficient.

[00500] Additionally, in some embodiments, the operation of determining coordinate information of the last significant coefficient by performing a calculation with respect to an initial horizontal coordinate and an initial vertical coordinate of the last significant coefficient may include the following operations.

[00501] Defines the width and height of the current block.

[00502] The horizontal coordinate of the last significant coefficient is obtained by subtracting the initial horizontal coordinate of the last significant coefficient from the width of the current block;

[00503] The vertical coordinate of the last significant coefficient is obtained by subtracting the initial vertical coordinate of the last significant coefficient from the height of the current block.

[00504] Information about the coordinates of the last significant coefficient is determined according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00505] It should be noted that the current block corresponding to the component of the current slice may be a block on which the zero output transformation has not been performed or a block on which the zero output transformation has been performed. Taking the block on which the zero output transformation has been performed as an example, in this case, the width of the current block may be 1 << log2ZoTbWidth, and the height of the current block may be 1 << log2ZoTbHeight. Then, in the case where the identification information about the component indicates that the reversal of the last significant coefficient is applied,

[00506] LastSignificantCoeffX= (1<<log2ZoTbWidth)-1-LastSignificantCoeffX;

[00507] LastSignificantCoeffY= (1<<log2ZoTbHeight)-1-LastSignificantCoeffY.

[00508] In this document, (LastSignificantCoeffX, LastSignificantCoeffY) on the right side of the formula may denote information about the coordinates of the last significant coefficient determined directly (i.e., the starting horizontal coordinate and the starting vertical coordinate of the last significant coefficient). (LastSignificantCoeffX, LastSignificantCoeffY) on the left side of the formula may denote information about the coordinates of the last significant coefficient obtained by coordinate reversal (i.e., information about the coordinates of the last significant coefficient provided to the bitstream in the case of applying the reversal of the location of the last significant coefficient to the current block).

[00509] In some embodiments, the operation of providing information about the coordinates of the last significant coefficient to the bitstream may include the following operations.

[00510] Information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient are determined according to the information about the coordinate of the last significant coefficient.

[00511] Information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient are provided in a bitstream.

[00512] It should be noted that the information about the prefix of the horizontal coordinate of the last significant coefficient may be designated as last_sig_coeff_x_prefix. The information about the prefix of the vertical coordinate of the last significant coefficient may be designated as last_sig_coeff_y_prefix. The information about the suffix of the horizontal coordinate of the last significant coefficient may be designated as last_sig_coeff_x_suffix. The information about the suffix of the vertical coordinate of the last significant coefficient may be designated as last_sig_coeff_y_suffix. Then, last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be provided to the bitstream, so that the decoder determines the coordinate information of the last significant coefficient by analyzing the bitstream.

[00513] In embodiments of the present invention, the given scanning order may be a diagonal scanning order, a zigzag scanning order, a horizontal scanning order, a vertical scanning order, a 4×4 sub-block scanning order, etc., which is in no way limited herein.

[00514] Thus, in some cases such as encoding and decoding video with high bit depth, high quality, high bit rate or lossless compression, embodiments of the present invention provide a method for modifying a mode for obtaining the location of the last significant coefficient. That is, usually, the method for encoding and decoding coefficients is the same as the existing method in the prior art. Usually, last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may be configured to encode the abscissa of the location of the last significant coefficient, i.e., the horizontal distance relative to the upper left corner of the current block; and last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be configured to encode the ordinate of the location of the last significant coefficient, i.e., the vertical distance relative to the upper left corner of the current block, as shown in Fig. 10A. When encoding and decoding video with high bit depth, high quality, high bit rate or lossless compression, the location of the last significant coefficient is usually close to the lower right corner of the region that includes all possible non-zero coefficients in the current block. In this case, last_sig_coeff_x_prefix and last_sig_coeff_x_suffix may be configured to encode the horizontal distance between the location of the last significant coefficient and the lower right corner of the region that includes all possible non-zero coefficients in the current block, and last_sig_coeff_y_prefix and last_sig_coeff_y_suffix may be configured to encode the vertical distance between the location of the last significant coefficient and the lower right corner of the region that includes all possible non-zero coefficients in the current block, as shown in Fig. 10B. Therefore, in the embodiments of the present invention, reverse_last_sig_coeff_flag is introduced, thereby solving the problem of increased resource consumption caused by encoding large values in a bitstream.

[00515] Additionally, for each of the color components of the current slice, the slice-level reverse_last_sig_coeff_flag (i.e., the identification information about the sh_reverse_last_sig_coeff_flag component of the current slice) may provide the ability to separately control whether to apply the reversal of the last significant coefficient to the color component.

[00516] In embodiments of the present invention, the component may comprise a first color component, a second color component, and a third color component.

[00517] In a particular example, the first color component is a luminance component. The second color component is a first chroma component. The third color component is a second chroma component. The luminance component may be denoted as Y. The first chroma component may be denoted as U(Cb). The second chroma component may be denoted as V(Cr).

[00518] In another specific example, the first color component is a red component, the second color component is a green component, and the third color component is a blue component. The red component may be designated as R. The green component may be designated as G. The blue component may be designated as B.

[00519] Additionally, in some embodiments, when the component includes a first color component, a second color component, and a third color component, the method may further include the following operations.

[00520] It is determined whether the first color component, the second color component, and the third color component of the current slice share identification information about the component based on the relationship between the properties of the first color component, the second color component, and the third color component.

[00521] The number of parts of the component identification information of the current slice is determined according to the definition. The number of parts of the component identification information may be 1, 2, or 3.

[00522] In particular, the operation of determining the number of parts of the identification information about the component may include the following operation.

[00523] The number of parts of the component identification information of the current slice is determined to be 1 if one part of the component identification information is shared by the first color component, the second color component, and the third color component of the current slice.

[00524] Alternatively, the number of pieces of identification information about a component of the current slice is determined to be 2 if one piece of identification information about a component is shared by two of the first color component, the second color component, and the third color component of the current slice.

[00525] Alternatively, the number of parts of the component identification information of the current slice is determined to be 3 if each of the first color component, the second color component, and the third color component of the current slice has a separate part of the component identification information.

[00526] In embodiments of the present invention, since the properties of the corresponding color components may differ and some inter-component techniques are used, the corresponding color components may not always be compatible in the residual distribution. For example, when encoding and decoding video with a very high bit rate and very high quality requirements, the significant coefficients of different components may be the same in the distribution, for example, they are all located close to the lower right corner of the region including possible significant coefficients. However, in some cases of encoding and decoding video with a not particularly high bit rate and not particularly high quality requirements, the significant coefficients of different components may be different in the distribution. For example, all the significant coefficients of the Y component are close to the lower right corner of the region including possible significant coefficients, and the significant coefficients of the U/V component are distributed only in the upper left corner. Alternatively, the significant coefficients of the U component are also close to the lower right corner, and the significant coefficients of the V component are distributed only in the upper left corner.

[00527] Therefore, in embodiments of the present invention, one or more pieces of component identification information may be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. For example, one component identification may control the application to the luma component, and another component identification may control the application to two chroma components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. For example, the three color components are R, G, and B in RGB format, or Y, Cb, and Cr (or Y, U, and V) in YUV format.

[00528] In a possible implementation, when the number of pieces of identification information about a component is 1, the operation of determining identification information about a component of the current slice may include determining a first identification information about a component of the current slice.

[00529] Accordingly, the method may further include the following operation. If the value of the first component identification information is a first value, it is determined that the reversal of the last significant coefficient is applied to each of the first color component, the second color component, and the third color component of the current slice. Alternatively, if the value of the first component identification information is a second value, it is determined that the reversal of the last significant coefficient is not applied to any of the first color component, the second color component, and the third color component of the current slice.

[00530] In another possible implementation, when the number of pieces of component identification information is 2, the operation of determining component identification information of the current slice may include determining a second component identification information and a third component identification information of the current slice.

[00531] Accordingly, the method may further include the following operation. If the value of the second component identification information is the first value, it is determined that the reversal of the location of the last significant coefficient is applied to each of the two color components of the first color component, the second color component, and the third color component of the current slice. Alternatively, if the value of the second component identification information is the second value, it is determined that the reversal of the location of the last significant coefficient is not applied to any of the two color components of the first color component, the second color component, and the third color component of the current slice.

[00532] If the value of the third component identification information is the first value, it is determined that the reversal of the location of the last significant coefficient is applied to another color component of the first color component, the second color component, and the third color component of the current slice, other than the two color components. Alternatively, if the value of the third component identification information is the second value, it is determined that the reversal of the location of the last significant coefficient is not applied to another color component of the first color component, the second color component, and the third color component of the current slice, other than the two color components.

[00533] In another possible implementation, when the number of pieces of component identification information is 3, the operation of determining component identification information of the current slice may include determining a fourth component identification information, a fifth component identification information, and a sixth component identification information of the current slice.

[00534] Accordingly, the method may further include the following operation. If the value of the fourth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the first color component of the current slice. Alternatively, if the value of the fourth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the first color component of the current slice.

[00535] If the value of the fifth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the second color component of the current slice. Alternatively, if the value of the fifth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the second color component of the current slice.

[00536] If the value of the sixth component identification information is the first value, it is determined that the reversal of the last significant coefficient is applied to the third color component of the current slice. Alternatively, if the value of the sixth component identification information is the second value, it is determined that the reversal of the last significant coefficient is not applied to the third color component of the current slice.

[00537] It should be noted that the first value and the second value may differ. The first value and the second value may be parametric or may be numeric. In a specific example, the first value is set to 1 and the second value is set to 0, which, however, is not limited in any way.

[00538] It should be further noted that the component identification information in this case may be a slice level flag and may be designated as sh_reverse_last_sig_coeff_flag[cIdx]. cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may include sh_reverse_last_sig_coeff_flag[0], sh_reverse_last_sig_coeff_flag[1], and sh_reverse_last_sig_coeff_flag[2]. The fourth component identification information may be designated as sh_reverse_last_sig_coeff_flag[0] to indicate whether the reversal of the last significant coefficient location is applied to the current block corresponding to the first color component of the current slice. The fifth component identification information may be denoted as sh_reverse_last_sig_coeff_flag[1] to indicate whether the reversal of the last significant coefficient is applied to the current block corresponding to the second color component of the current slice. The sixth component identification information may be denoted as sh_reverse_last_sig_coeff_flag[2] to indicate whether the reversal of the last significant coefficient is applied to the current block corresponding to the third color component of the current slice.

[00539] Illustratively, taking the YUV format as an example, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. If sh_reverse_last_sig_coeff_flag[0] has a value of 1, it may be determined that the reversal of the last significant coefficient is applied to the block corresponding to the first color component of the current slice (such as the Y component). If sh_reverse_last_sig_coeff_flag[1] has a value of 1, it may be determined that the reversal of the last significant coefficient is applied to the block corresponding to the second color component of the current slice (such as the U component). If sh_reverse_last_sig_coeff_flag[2] is set to 1, it can be specified that the reversal of the last significant coefficient is applied to the block corresponding to the third color component of the current slice (such as the V component).

[00540] It should be further noted that when the third identification information about the syntax element indicates that the range extension is applied to the current sequence, all possible coefficients to be coded must be coded by default. That is, the location of the last significant coefficient is no longer used. Instead, all possible non-zero coefficients in the current block are scanned in a given scanning order. Therefore, in embodiments of the present invention, identification information about the resolved last coefficient may also be entered to determine whether the location of the last coefficient is applied to the current block.

[00541] In some embodiments, when the third identification information about the syntax element indicates that a range extension is applied to the current sequence, the method may further include the following operations.

[00542] Determine identification information about the last resolved coefficient of the current block.

[00543] When the identification information about the resolved last coefficient indicates that the location of the last coefficient is applied to the current block, all coefficients located above the location of the last coefficient are encoded in a specified scanning order. The identification information about the resolved last coefficient, the identification information about the video, and the bit information obtained by encoding are provided in the bitstream.

[00544] It should be noted that the identification information about the last coefficient to be enabled may be designated as default_last_coeff_enabled_flag. In the embodiments of the present invention, the identification information about the last coefficient to be enabled may be at least one of sequence-level identification information, image-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited herein.

[00545] It should further be noted that in some embodiments, the operation of determining identification information about the resolved last coefficient of the current block may include the following operation.

[00546] The value of the identification information about the last coefficient to be resolved is determined as the first value if the location of the last coefficient is applied to the current block.

[00547] Alternatively, the value of the identification information about the last coefficient to be resolved is determined as the second value if the location of the last coefficient is not applied to the current block.

[00548] That is, the first value is 1 and the second value is 0 as an example. If it is determined that the location of the last coefficient is applied to the current block, default_last_coeff_enabled_flag has a value of 1. Alternatively, if it is determined that the location of the last coefficient is not applied to the current block, default_last_coeff_enabled_flag has a value of 0.

[00549] Additionally, in some embodiments, the location of the last coefficient is the lower right corner of a matrix formed by all possible non-zero coefficients in the current block. Alternatively, the location of the last coefficient is the last location of all possible non-zero coefficients in a given scan order in the current block.

[00550] It should be noted that in embodiments of the present invention, the location of the last coefficient does not represent the location of the last significant coefficient. This is because the coefficient at the location of the last coefficient may be equal to 0, while the coefficient at the location of the last significant coefficient is certainly not equal to 0.

[00551] In a specific example, the method may further include the following operation. The location of the last significant coefficient is set as the location of the last coefficient.

[00552] That is, in embodiments of the present invention, the location of the last significant coefficient may still be used. In this case, the location of the last significant coefficient must be placed at the last location of all possible non-zero coefficients in a given scan order in the current block.

[00553] Additionally, the location of the last coefficient may be designated as (LastCoeffX, LastCoeffY), i.e., the last location of all possible non-zero coefficients in a given scan order in the current block. In some embodiments, the method may further include the following operations.

[00554] Determine the width and height of the transformation block obtained by performing a specified operation on the current block.

[00555] Calculates coordinate information of the lower right corner of the transformation block according to the width and height of the transformation block.

[00556] The location of the last coefficient is determined according to the coordinate information of the lower right corner of the transformation block.

[00557] In this case, the specified operation includes at least a zero output operation.

[00558] It should be noted that (LastCoeffX, LastCoeffY) may denote the coordinate information of the lower right corner of the transformation block obtained after the zero output. (LastCoeffX, LastCoeffY) can be obtained as follows.

[00559] LastCoeffX= (1<<log2ZoTbWidth)-1.

[00560] LastCoeffY= (1<<log2ZoTbHeight)-1.

[00561] Accordingly, the location of the last coefficient can be determined according to (LastCoeffX, LastCoeffY) if default_last_coeff_enabled_flag is set to 1.

[00562] In a specific example, the location of the last significant coefficient is still used. In this case, the location of the last significant coefficient may be placed at the last location of all possible non-zero coefficients in a given scan order in the current block. In some embodiments, the method may further include the following operation.

[00563] When the location of the last significant coefficient is set as the location of the last coefficient, the location of the last significant coefficient is determined according to coordinate information of the lower right corner of the transformation block.

[00564] That is, the location of the last significant coefficient can be denoted as (LastSignificantCoeffX, LastSignificantCoeffY). (LastSignificantCoeffX, LastSignificantCoeffY) can be obtained as follows.

[00565] LastSignificantCoeffX= (1 <<log2ZoTbWidth)-1.

[00566] LastSignificantCoeffY= (1 <<log2ZoTbHeight)-1.

[00567] In this document, (LastSignificantCoeffX, LastSignificantCoeffY) may denote the coordinate information of the lower right corner of the transform block obtained after zero output. The location of the last significant coefficient may be determined according to (LastSignificantCoeffX, LastSignificantCoeffY) if default_last_coeff_enabled_flag is set to 1.

[00568] Additionally, when the identification information about the last coefficient to be resolved indicates that the location of the last coefficient is not applied to the current block, i.e., the identification information about the last coefficient to be resolved has a value of 0, in some embodiments, the method may further include the following operations.

[00569] Information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient are determined.

[00570] The location of the last significant coefficient is determined according to information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient.

[00571] All coefficients located above the location of the last significant coefficient are coded in a given scanning order. Information about a prefix of the horizontal coordinate of the last significant coefficient, information about a prefix of the vertical coordinate of the last significant coefficient, information about a suffix of the horizontal coordinate of the last significant coefficient, and information about a suffix of the vertical coordinate of the last significant coefficient are provided in the bitstream.

[00572] It should be noted that if the location of the last coefficient is not applied to the current block, it is necessary to determine the location of the last significant coefficient. In particular, there is no need to determine and provide in the bitstream last_sig_coeff_x_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_prefix and last_sig_coeff_y_suffix.

[00573] Thus, in some cases, such as encoding and decoding video with high bit depth, high quality, high bit rate or lossless compression, all possible coefficients to be encoded must be encoded by default when encoding the coefficients. Usually, the method of encoding and decoding the coefficients is still the same as the existing method in the prior art. All possible coefficients to be encoded must be encoded by default, that is, the location of the last significant coefficient is no longer used, instead, all possible non-zero coefficients in the current block are scanned in a given scan order. In other words, the location of the last coefficient to be encoded is placed in the last location of all possible non-zero coefficients in a given scan order in the current block. This location can usually refer to the lower right corner of the matrix consisting of all possible non-zero coefficients in the current block. Therefore, in embodiments of the present invention, default_last_coeff_enabled_flag is introduced, which thereby reduces or even eliminates syntax elements associated with the location of the last significant coefficient, provides resource savings and prevents waste.

[00574] Additionally, for each color component of the current slice, the identification information about the default last coefficient enabled (i.e., sh_default_last_coeff_enabled_flag) of the current slice may provide the ability to separately control whether to apply the default last coefficient to the color component.

[00575] In particular, the identification information about the default enabled last coefficient of the current slice may also be designated as sh_default_last_coeff_enabled_flag[cIdx]. cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may include sh_default_last_coeff_enabled_flag[0], sh_default_last_coeff_enabled_flag[1], and sh_default_last_coeff_enabled_flag[2]. sh_default_last_coeff_enabled_flag[0] may indicate whether the default last coefficient is applied to the current block corresponding to the first color component of the current slice. sh_default_last_coeff_enabled_flag[1] can specify whether the last default coefficient is applied to the current block corresponding to the second color component of the current slice. sh_default_last_coeff_enabled_flag[2] can specify whether the last default coefficient is applied to the current block corresponding to the third color component of the current slice.

[00576] In this case, in embodiments of the present invention, one or more pieces of component identification information may also be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components.

[00577] Illustratively, taking the YUV format as an example, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. If sh_default_last_coeff_enabled_flag[0] has a value of 1, it may be determined that the last default coefficient is applied to the block corresponding to the first color component of the current slice (such as the Y component). If sh_default_last_coeff_enabled_flag[1] has a value of 1, it may be determined that the last default coefficient is applied to the block corresponding to the second color component of the current slice (such as the U component). If sh_default_last_coeff_enabled_flag[2] is set to 1, it can be specified that the default last coefficient is applied to the block corresponding to the third color component of the current slice (such as the V component).

[00578] It should be further noted that when the third identification information about the syntax element indicates that the range extension is applied to the current sequence, the scanned sub-blocks need to be coded by default. In this case, there is no need to provide sb_coded_flag in the bitstream. That is, neither the encoder nor the decoder needs to process this flag, which thereby speeds up encoding and decoding. Therefore, embodiments of the present invention can further introduce identification information about the sub-block to be coded by default to determine whether the sub-block to be coded in the current block is coded by default.

[00579] In some embodiments, when the third identification information about the syntax element indicates that a range extension is applied to the current sequence, the method may further include the following operations.

[00580] Determine identification information about a default coded sub-block for a sub-block to be coded in the current block.

[00581] When the identification information about the default coded sub-block indicates that the sub-block to be coded is coded by default, all coefficients in the sub-block to be coded are coded. The identification information about the default coded sub-block and the bit information obtained by encoding are provided in the bitstream.

[00582] It should be noted that the identification information about the default coded sub-block may be designated as default_sb_coded_flag. In the embodiments of the present invention, the identification information about the default coded sub-block is at least one of sequence-level identification information, picture-level identification information, slice-level identification information, or block-level identification information, or even higher-level identification information (e.g., VUI, SEI, etc.), which is in no way limited here.

[00583] It should be further noted that in some embodiments, the operation of determining identification information about a default coded sub-block for a sub-block to be coded may include the following operation. A value of the identification information about the default coded sub-block is determined as a first value if the sub-block to be coded is coded by default. Alternatively, a value of the identification information about the default coded sub-block is determined as a second value if the sub-block to be coded is not coded by default.

[00584] Accordingly, taking the first value equal to 1 and the second value equal to 0 as an example, default_sb_coded_flag has a value of 1 if it is determined that the sub-block to be coded should be coded by default. Alternatively, default_sb_coded_flag has a value of 0 if it is determined that the sub-block to be coded should not be coded by default.

[00585] When the sub-block to be coded is to be coded by default, default_sb_coded_flag has a value of 1, which means that sb_coded_flag has a value of 1, i.e., there is no need to code sb_coded_flag. However, when the sub-block to be coded is not to be coded by default, i.e., the identification information about the default coded sub-block indicates that the sub-block to be coded is not to be coded by default, in some embodiments, the method may further include the following operation. Identification information about the coded sub-block is determined for the sub-block to be coded, and the identification information about the coded sub-block is provided to the bitstream.

[00586] Additionally, in some embodiments, the operation of determining identification information about a coded sub-block for a sub-block to be coded may include the following operation. The value of the identification information about the coded sub-block is determined as a first value if encoding is required for the sub-block to be coded. Alternatively, the value of the identification information about the coded sub-block is determined as a second value if all coefficients in the sub-block to be coded are zero.

[00587] In embodiments of the present invention, the identification information about the sub-block to be coded may be designated as sb_coded_flag. A first value of 1 and a second value of 0 are taken as an example. If it is determined that the sub-block to be coded is to be coded, this means that the sub-block to be coded contains significant coefficients to be coded. In this case, sb_coded_flag has a value of 1. Alternatively, if it is determined that it is not necessary to code the sub-block to be coded, this means that all coefficients in the sub-block to be coded are zero. In this case, sb_coded_flag has a value of 0.

[00588] Thus, in a certain situation, when encoding coefficients, the scanned sub-blocks must be encoded by default, or the scanned sub-blocks contain significant coefficients by default. Usually, the method for encoding the coefficients is still the same as the existing method in the prior art. A certain situation may be, for example, encoding and decoding of video with a high bit depth, high quality, high bit rate, or lossless compression. In this situation, there are many significant coefficients, and almost all of the scanned sub-blocks must be encoded, or almost all of the scanned sub-blocks contain significant coefficients. In this case, there is no need to provide sb_coded_flag in the bitstream. Thus, there is no need for the encoder to process this flag, which thereby speeds up encoding and decoding. Removing the almost non-existent flag further improves the compression efficiency.

[00589] Additionally, for each color component of the current slice, the identification information about the default coded sub-block (i.e., sh_default_sb_coded_flag) of the current slice may provide the ability to separately control whether to apply the default coded sub-block to the color component.

[00590] In particular, the identification information about the default coded sub-block of the current slice may also be designated as sh_default_sb_coded_flag[cIdx]. cIdx may have a value of 0, 1, or 2. In particular, when the three pieces of component identification information are configured to control the three color components respectively, the three pieces of component identification information may include sh_default_sb_coded_flag[0], sh_default_sb_coded_flag[1], and sh_default_sb_coded_flag[2]. sh_default_sb_coded_flag[0] may indicate whether the sub-block of the current block that corresponds to the first color component of the current slice is coded by default. sh_default_sb_coded_flag[1] may indicate whether the sub-block of the current block that corresponds to the second color component of the current slice is coded by default. sh_default_sb_coded_flag[2] can specify whether the subblock of the current block that corresponds to the third color component of the current slice is encoded by default.

[00591] In this case, in embodiments of the present invention, one or more pieces of component identification information may also be configured to control the application of embodiments of the present invention to different color components. Illustratively, one piece of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, two pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to three color components. Alternatively, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components.

[00592] In a specific example, taking the YUV format as an example, three pieces of component identification information may be configured to control whether to apply the method according to embodiments of the present invention to each of the three color components. If sh_default_sb_coded_flag[0] has a value of 1, it may be determined that the sub-block of the block that corresponds to the first color component of the current slice (such as the Y component) is coded by default. If sh_default_sb_coded_flag[1] has a value of 1, it may be determined that the sub-block of the block that corresponds to the second color component of the current slice (such as the U component) is coded by default. If sh_default_sb_coded_flag[2] has a value of 1, it may be determined that the sub-block of the block that corresponds to the third color component of the current slice (such as the V component) is coded by default.

[00593] In short, for all color components in a video, one piece of identification information may be applied to all color components for using the method according to the embodiments of the present invention. Alternatively, different pieces of identification information may be applied to separately control the corresponding color components for using the method according to the embodiments of the present invention. Alternatively, two pieces of identification information may be applied to control all color components for using the method according to the embodiments of the present invention. In other words, more than one piece of identification information may be applied to control different color components for using the method according to the embodiments of the present invention. Herein, all color components may be R, G, and B of RGB video format, or Y, U, and V (Y, Cb, and Cr) of YUV video format, or the like.

[00594] The present invention further provides a coding method performed by an encoder. The method determines identification information about a component of a current slice and a location of the last significant coefficient of a current block corresponding to the component of the current slice. Information about the coordinates of the last significant coefficient of the current block is determined according to the identification information about the component and the location of the last significant coefficient. Coefficients located above the location of the last significant coefficient are encoded in a predetermined scanning order. Bit information obtained by encoding, identification information about the component and coordinate information of the last significant coefficient are provided in a bitstream. Thus, in a scenario of encoding and decoding video with a high bit depth, high bit rate, high quality or lossless, a reasonable mode of obtaining the last significant coefficient is set according to the distribution law of significant coefficients, which thereby reduces resource consumption caused by encoding in a bitstream and improves compression efficiency. In addition, since the corresponding color components may be different in the distribution of significant coefficients, it is also possible to precisely control the corresponding mode of obtaining the last significant coefficient for each color component, i.e., separately controlling whether to apply the last significant coefficient reversal technology to each color component, thereby further improving the compression efficiency.

[00595] In another embodiment of the present invention, embodiments of the present invention provide a bitstream. The bitstream may be generated by performing bit encoding on information to be encoded. The information to be encoded comprises at least one of first identification information about a syntax element, second identification information about a syntax element, third identification information about a syntax element, identification information about a component, identification information about a resolved last coefficient, or identification information about a default coded sub-block.

[00596] The first identification information about the syntax element indicates whether the reversal of the location of the last significant coefficient is allowed for the current sequence. The second identification information about the syntax element indicates whether the version of the standard extension is applied to the current sequence. The third identification information about the syntax element indicates whether the range extension is applied to the current sequence. The identification information about the component indicates whether the reversal of the location of the last significant coefficient is applied to the component of the current slice. The identification information about the allowed last coefficient indicates whether the location of the last coefficient is applied to the current block. The identification information about the default coded sub-block indicates whether the sub-block to be coded is coded by default in the current block. The current sequence contains the current slice. The current slice contains the current block.

[00597] In embodiments of the present invention, an encoding system is further provided. The encoding system may comprise an encoder and a decoder. The encoder generates a bit stream and transmits the bit stream to the decoder, so that the decoder analyzes the bit stream to obtain corresponding decoded information, such as first identification information about a syntax element, a second identification information about a syntax element, a third identification information about a syntax element, identification information about a component, identification information about a resolved last coefficient, identification information about a default coded sub-block, information about the coordinates of the last significant coefficient of the current block, and the like.

[00598] In another embodiment of the present invention, based on the same concepts of the present invention as in the previous embodiments, Fig. 12 shows a diagram of the structure of an encoder 120 according to embodiments of the present invention. As shown in Fig. 12, the encoder 120 includes a first determining unit 1201 and an encoding unit 1202.

[00599] The first determining unit 1201 is configured to determine identification information about a component of the current slice and a location of the last significant coefficient of the current block corresponding to the component of the current slice.

[00600] The first determining unit 1201 is further configured to determine information about the coordinates of the last significant coefficient of the current block according to the identification information about the component and the location of the last significant coefficient.

[00601] The encoding unit 1202 is configured to encode the coefficients located above the location of the last significant coefficient in a given scanning order and provide in a bitstream the bit information obtained by encoding, the identification information about the component and the information about the coordinates of the last significant coefficient.

[00602] In some embodiments, the first determining unit 1201 is further configured to determine first identification information about a syntax element and determine identification information about a component of a current slice in response to the first identification information about a syntax element indicating that reversal of the last significant coefficient is permitted for the current sequence. The current sequence comprises the current slice.

[00603] In some embodiments, the first determining unit 1201 is further configured to determine a second identification information about a syntax element, determine a third identification information about a syntax element in response to the second identification information about a syntax element indicating that a version of an extension of the standard is applied to the current sequence, and determine a first identification information about a syntax element in response to a third identification information about a syntax element indicating that a range extension is applied to the current sequence.

[00604] In some embodiments, the first determining unit 1201 is further configured to determine the value of the second identification information about the syntax element as a first value in response to applying the extension version of the standard to the current sequence; or to determine the value of the second identification information about the syntax element as a second value in response to not applying the extension version of the standard to the current sequence.

[00605] In some embodiments, encoding unit 1202 is further configured to provide second identification information about the syntax element in the bitstream.

[00606] In some embodiments, the first determining unit 1201 is further configured to determine the value of the third identification information about the syntax element as a first value in response to applying a range extension to the current sequence; or to determine the value of the third identification information about the syntax element as a second value in response to not applying a range extension to the current sequence.

[00607] In some embodiments, encoding unit 1202 is further configured to provide third identification information about the syntax element in the bitstream.

[00608] In some embodiments, applying range extension to a current sequence includes the following: the current sequence has at least one of the following: high bit depth, high quality, high bit rate, high frame rate, or lossless compression.

[00609] In some embodiments, the first determining unit 1201 is further configured to determine the value of the first identification information about the syntax element as a first value in response to allowing a reversal of the last significant coefficient for the current sequence; or to determine the value of the first identification information about the syntax element as a second value in response to prohibiting a reversal of the last significant coefficient for the current sequence.

[00610] In some embodiments, encoding unit 1202 is further configured to provide first identification information about the syntax element in the bitstream.

[00611] In some embodiments, the first determining unit 1201 is further configured to determine a value of the identification information about the component as a first value in response to applying a reversal of the last significant coefficient to the component of the current slice; or to determine a value of the identification information about the component as a second value in response to not applying a reversal of the last significant coefficient to the component of the current slice.

[00612] In some embodiments, the component comprises at least one of a first color component, a second color component, or a third color component.

[00613] The first color component is a luminance component, the second color component is a first chroma component, and the third color component is a second chroma component.

[00614] Alternatively, the first color component is a red component, the second color component is a green component, and the third color component is a blue component.

[00615] In some embodiments, the first determining unit 1201 is further configured to, when the component comprises a first color component, a second color component and a third color component, determine the number of parts of the identification information about the component of the current slice to be 1 in response to the fact that one part of the identification information about the component is shared by the first color component, the second color component and the third color component of the current slice; or determine the number of parts of the identification information about the component of the current slice to be 2 in response to the fact that one part of the identification information about the component is shared by two color components of the first color component, the second color component and the third color component of the current slice; or determine the number of parts of the identification information about the component of the current slice to be 3 in response to the fact that each of the first color component, the second color component and the third color component of the current slice has a separate part of the identification information about the component.

[00616] In some embodiments, the first determining node 1201 is further configured to determine first identification information about a component of the current slice.

[00617] Accordingly, the first determining unit 1201 is further configured to determine a value of the first identification information about the component as a first value in response to the fact that a reversal of the location of the last significant coefficient is applied to each of the first color component, the second color component and the third color component of the current slice.

[00618] In some embodiments, the first determining node 1201 is further configured to determine the second identification information about the component and the third identification information about the component of the current slice.

[00619] Accordingly, the first determining unit 1201 is further configured to determine a value of the second component identification information as a first value in response to the fact that a reversal of the last significant coefficient is applied to each of the two color components of the first color component, the second color component, and the third color component of the current slice; and to determine a value of the third component identification information as a first value in response to the fact that a reversal of the last significant coefficient is applied to another color component other than the two color components of the first color component, the second color component, and the third color component of the current slice.

[00620] In some embodiments, the first determining unit 1201 is further configured to determine a fourth component identification information, a fifth component identification information, and a sixth component identification information of the current slice.

[00621] Accordingly, the first determining unit 1201 is further configured to determine a value of the fourth component identification information as a first value in response to the fact that the reversal of the last significant coefficient is applied to the first color component of the current slice; determine a value of the fifth component identification information as a first value in response to the fact that the reversal of the last significant coefficient is applied to the second color component of the current slice; and determine a value of the sixth component identification information as a first value in response to the fact that the reversal of the last significant coefficient is applied to the third color component of the current slice.

[00622] In some embodiments, the location of the last significant coefficient includes a starting horizontal coordinate and a starting vertical coordinate of the last significant coefficient. The starting horizontal coordinate and the starting vertical coordinate are a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block, respectively.

[00623] Accordingly, the first determining unit 1201 is further configured to determine the coordinate information of the last significant coefficient by performing a calculation with respect to the initial horizontal coordinate and the initial vertical coordinate of the last significant coefficient in response to the fact that the value of the component identification information is a first value; or determine the coordinate information of the last significant coefficient directly according to the initial horizontal coordinate and the initial vertical coordinate of the last significant coefficient in response to the fact that the value of the component identification information is a second value.

[00624] In some embodiments, the first determining unit 1201 is further configured to determine the width and the height of the current block; obtain a horizontal coordinate of the last significant coefficient by subtracting an initial horizontal coordinate of the last significant coefficient from the width of the current block; obtain a vertical coordinate of the last significant coefficient by subtracting an initial vertical coordinate of the last significant coefficient from the height of the current block; and determine information about the coordinates of the last significant coefficient according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00625] In some embodiments, the first determining unit 1201 is further configured to determine the coordinate information of the last significant coefficient as a horizontal distance and a vertical distance between the location of the last significant coefficient and the lower right corner of the current block in response to the fact that the value of the component identification information is a first value; or determine the coordinate information of the last significant coefficient as a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block in response to the fact that the value of the component identification information is a second value.

[00626] In some embodiments, the first determining unit 1201 is further configured to determine information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient according to the coordinate information of the last significant coefficient.

[00627] The encoding unit 1202 is further configured to provide information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient to the bitstream.

[00628] In some embodiments, the first determining unit 1201 is further configured to determine identification information about a resolvable last coefficient of the current block in response to a third identification information about a syntax element indicating that range extension is applied to the current sequence.

[00629] The encoding unit 1202 is further configured to encode coefficients located above the location of the last coefficient in a given scanning order in response to identification information about the resolved last coefficient indicating that the location of the last coefficient is applied to the current block, and to provide bit information obtained by encoding and the identification information about the resolved last coefficient in a bitstream.

[00630] In some embodiments, the first determining unit 1201 is further configured to determine the value of the identification information about the resolved last coefficient as a first value in response to the fact that the location of the last coefficient is applied to the current block; or determine the value of the identification information about the resolved last coefficient as a second value in response to the fact that the location of the last coefficient is not applied to the current block.

[00631] In some embodiments, the location of the last coefficient is the lower right corner of a matrix consisting of all possible non-zero coefficients in the current block. Alternatively, the location of the last coefficient is the last location of all possible non-zero coefficients in a given scan order in the current block.

[00632] In some embodiments, the first determining unit 1201 is further configured to set the location of the last significant coefficient as the location of the last coefficient.

[00633] In some embodiments, the first determining unit 1201 is further configured to determine the width and the height of the transformation block obtained by performing a predetermined operation with respect to the current block; calculate information about the coordinates of the lower right corner of the transformation block according to the width and the height of the transformation block; and determine the location of the last coefficient according to the information about the coordinates of the lower right corner of the transformation block.

[00634] In some embodiments, the specified operation includes at least a zero output operation.

[00635] In some embodiments, the first determining unit 1201 is further configured to determine the location of the last significant coefficient according to the coordinate information of the lower right corner of the transform block in response to setting the location of the last significant coefficient as the location of the last coefficient.

[00636] In some embodiments, the first determining unit 1201 is further configured to determine information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient in response to the fact that the identification information about the resolved last coefficient indicates that the location of the last coefficient is not applied to the current block; and determine the location of the last significant coefficient according to the information about the prefix of a horizontal coordinate of the last significant coefficient, the prefix of a vertical coordinate of the last significant coefficient, the suffix of a horizontal coordinate of the last significant coefficient, and the suffix of a vertical coordinate of the last significant coefficient.

[00637] The encoding unit 1202 is further configured to encode the coefficients located above the location of the last significant coefficient in a given scanning order and provide information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient to the bitstream.

[00638] In some embodiments, the first determining unit 1201 is further configured to determine identification information about a default coded sub-block for a sub-block to be coded in the current block in response to a third identification information about a syntax element indicating that a range extension has been applied to the current sequence.

[00639] The encoding unit 1202 is further configured to encode coefficients in a sub-block to be encoded in response to identification information about a default-encoded sub-block indicating that the sub-block to be encoded is default-encoded, and to provide the identification information about the default-encoded sub-block and bit information obtained by encoding to a bitstream.

[00640] In some embodiments, the first determining unit 1201 is further configured to determine identification information about a coded sub-block for a sub-block to be coded in response to identification information about a default coded sub-block indicating that the sub-block to be coded is not coded by default.

[00641] The encoding unit 1202 is further configured to provide identification information about the sub-block being encoded into the bitstream.

[00642] In some embodiments, the first determining unit 1201 is further configured to determine a value of the identification information about the default-coded sub-block as a first value in response to the fact that the sub-block to be coded is coded by default, or to determine a value of the identification information about the default-coded sub-block as a second value in response to the fact that the sub-block to be coded is not coded by default.

[00643] In some embodiments, the first determining unit 1201 is further configured to determine the value of the identification information about the sub-block to be coded as a first value in response to the fact that the sub-block to be coded is to be coded, or to determine the value of the identification information about the sub-block to be coded as a second value in response to the fact that all coefficients in the sub-block to be coded are equal to zero.

[00644] In some embodiments, the first value is 1 and the second value is 0.

[00645] It is understood that in embodiments of the present invention, a "node" may be a part of a circuit, a part of a processor, a part of a program or software, and/or the like. Of course, a "node" may be a module or may be non-modular. Furthermore, components in embodiments may be integrated into a single processing part or exist as separate physical nodes, respectively. Alternatively, two or more nodes may be integrated into a single node. The integrated node may be implemented in the form of a hardware or software functional node(s).

[00646] When implemented in the form of a software functional module and sold or used as a stand-alone product, the integrated module in this case can also be stored on a machine-readable storage medium. Based on this understanding, an essential part or a part contributing to the prior art of the technical solution of the embodiment of the present invention, or the entire technical solution or a part thereof can be in the form of a software product, wherein this software product is stored on a storage medium and contains a number of instructions allowing a computer device (such as a personal computer, a server, a network device and/or the like) or a processor to execute the entire method or a part thereof in the embodiments of the present invention. Storage media include various media capable of storing program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, a CD and/or the like.

[00647] Accordingly, in embodiments of the present invention, a computer storage medium is provided, implemented in the encoder 120. The computer storage medium stores therein a computer program, which, when executed by the first processor, implements the method according to any of the above-described embodiments.

[00648] Based on the composition of the encoder 120 and the computer storage medium, Fig. 13 shows a diagram of the hardware structure of the encoder 120 according to embodiments of the present invention. As shown in Fig. 13, the encoder may include a first communication interface 1301, a first memory 1302 and a first processor 1303. Various components may be interconnected via a first equipment 1304 in the form of buses. It is understood that the first equipment 1304 in the form of buses is configured to implement a connection and communication between these components. In addition to the data bus, the first equipment 1304 in the form of buses may further include a power bus, a control bus and a status signal bus. However, for clarity of description, various buses are designated as the first equipment 1304 in the form of buses in Fig. 13.

[00649] The first communication interface 1301 may be configured to perform sending and receiving a signal when performing sending and receiving information using another external network element.

[00650] The first memory device 1302 is configured to store therein a computer program executed by the first processor 1303.

[00651] The first processor 1303 is configured to execute a computer program for performing the following operations.

[00652] Determine identification information about a component of the current slice and the location of the last significant coefficient of the current block corresponding to the component of the current slice.

[00653] Determine coordinate information of the last significant coefficient of the current block according to identification information of the component and the location of the last significant coefficient.

[00654] Coefficients located above the location of the last significant coefficient are encoded in a given scanning order; and bit information obtained by encoding, identification information about the component, and information about the coordinates of the last significant coefficient are provided to the bit stream.

[00655] It is understood that the first memory device 1302 according to embodiments of the present invention may be a volatile and/or non-volatile memory device. The non-volatile memory device may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory device may be a random access memory (RAM), which performs the function of an external cache. By way of illustration and not limitation, a variety of RAM forms may be available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous channel dynamic random access memory (synchronous channel DRAM, SLDRAM), direct resident random access memory (DRRAM), and the like. The first memory 1302 used in the systems and methods of the present invention is intended to include, but is not limited to, these and any other suitable types of memory.

[00656] The first processor 1303 may be an integrated circuit chip capable of processing a signal. In an implementation, the operations of an embodiment of the method herein may be performed by an integrated logic circuit of hardware in the first processor 1303 or instructions in the form of software. The first processor 1303 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete logic element, or a transistor logic device, a discrete hardware component, and the like. The first processor may implement or execute various methods, operations, and logical flow charts according to embodiments of the present invention. The general-purpose processor may be a microprocessor or any conventional processor. The operations of the method described in the embodiments of the present invention may be directly implemented as performed by a hardware encoding processor or a combination of hardware and software modules in a encoding processor. The software module may be located in a data carrier established in the prior art, such as a random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), electrically rewritable programmable memory, a register, etc. The data carrier may be located in the first memory 1302. The first processor 1303 may read information in the first memory 1302 and perform the method operation in this case by means of the processor hardware.

[00657] It is understood that embodiments according to the present invention can be implemented by means of hardware, software, firmware, middleware, microcode, or a combination of the listed elements. For a hardware implementation, the processing unit can be implemented in one or more application-specific integrated circuits (ASICs), DSPs, digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontroller units (MCUs), microprocessors, and other electronic units for implementing the function of the present invention, or combinations thereof. For a hardware implementation, the technology according to the present invention can be implemented by means of a module, such as a process, a function, etc., that implements the function of the present invention. The software code can be stored in a memory and executed by the processor. The memory can be implemented inside or outside the processor.

[00658] Alternatively, as another embodiment, the first processor 1303 may further be configured to execute the method according to the above-described embodiment when executing a computer program.

[00659] In an embodiment, an encoder is provided. The encoder may comprise a first determining unit and an encoding unit. Accordingly, in a scenario of encoding and decoding a video with a high bit depth, a high bit rate, a high quality, or a lossless video, a reasonable mode of acquiring the last significant coefficient is set according to a distribution law of the significant coefficients, thereby reducing the resource consumption caused by encoding in a bit stream and improving the compression efficiency. In addition, since the corresponding color components may be different in the distribution of the significant coefficients, it is possible to accurately control the corresponding mode of acquiring the last significant coefficient for each color component, i.e., by separately controlling whether to apply the reversal technology of the last significant coefficient to each color component, thereby further improving the compression efficiency.

[00660] In another embodiment of the present invention, based on the same concepts of the present invention as in the previous embodiments, Fig. 14 shows a diagram of the structure of a decoder 140 according to embodiments of the present invention. As shown in Fig. 14, the decoder 140 may include an analysis unit 1401 and a second determination unit 1402.

[00661] The analysis unit 1401 is configured to determine, by analyzing the bit stream, identification information about a component of the current slice and information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice.

[00662] The second determining unit 1402 is configured to obtain a location of the last significant coefficient of the current block by performing a calculation with respect to information about the coordinates of the last significant coefficient in response to identification information about the component indicating that a change in the location to the inverse of the last significant coefficient is applied to the component of the current slice.

[00663] The analysis unit 1401 is further configured to determine the coefficients of the current block by decoding the coefficients located above the location of the last significant coefficient, in a given scanning order.

[00664] In some embodiments, the analysis unit 1401 is further configured to determine the first identification information about the syntax element by analyzing the bitstream.

[00665] The second determining unit 1402 is further configured to determine identification information about a component of the current slice by analyzing a bitstream in response to the first identification information about a syntax element indicating that reversal of the last significant coefficient is permitted for the current sequence. The current sequence may include the current slice.

[00666] In some embodiments, the analysis unit 1401 is further configured to determine a second identification information about a syntax element by analyzing a bitstream; determine a third identification information about a syntax element by analyzing a bitstream in response to the second identification information about a syntax element indicating that a version of an extension of the standard is applied to the current sequence; and determine a first identification information about a syntax element by analyzing a bitstream in response to a third identification information about a syntax element indicating that a range extension is applied to the current sequence.

[00667] In some embodiments, the second determination unit 1402 is further configured to determine that the second identification information about the syntax element indicates that the version of the extension of the standard is applied to the current sequence, in response to the fact that the value of the second identification information about the syntax element is a first value; or determine that the second identification information about the syntax element indicates that the version of the extension of the standard is not applied to the current sequence, in response to the fact that the value of the second identification information about the syntax element is a second value.

[00668] In some embodiments, the second determining unit 1402 is further configured to determine that the third identification information about the syntax element indicates that the range extension is applied to the current sequence in response to the fact that the value of the third identification information about the syntax element is a first value; or determine that the third identification information about the syntax element indicates that the range extension is not applied to the current sequence in response to the fact that the value of the third identification information about the syntax element is a second value.

[00669] In some embodiments, applying range extension to a current sequence may include the following: the current sequence has at least one of the following: high bit depth, high quality, high bit rate, high frame rate, or lossless compression.

[00670] In some embodiments, the second determining unit 1402 is further configured to determine that the first identification information about the syntax element indicates that reversal of the last significant coefficient is permitted for the current sequence, in response to the fact that the value of the first identification information about the syntax element is a first value; or determine that the first identification information about the syntax element indicates that reversal of the last significant coefficient is prohibited for the current sequence, in response to the fact that the value of the first identification information about the syntax element is a second value.

[00671] In some embodiments, the second determining unit 1402 is further configured to determine that the identification information about the component indicates that a reversal of the last significant coefficient is applied to the component of the current slice, in response to the fact that the value of the identification information about the component is a first value; or determine that the identification information about the component indicates that a reversal of the last significant coefficient is not applied to the component of the current slice, in response to the fact that the value of the identification information about the component is a second value.

[00672] In some embodiments, the second determining unit 1402 is further configured to determine the location of the last significant coefficient of the current block directly according to the information about the coordinates of the last significant coefficient in response to the identification information about the component indicating that a change in the location to the inverse of the last significant coefficient is not applied to the component of the current slice.

[00673] The analysis unit 1401 is further configured to determine the coefficients of the current block by decoding the coefficients located above the location of the last significant coefficient, in a given scanning order.

[00674] In some embodiments, the component comprises at least one of a first color component, a second color component, or a third color component.

[00675] The first color component is a luminance component, the second color component is a first chroma component, and the third color component is a second chroma component.

[00676] Alternatively, the first color component is a red component, the second color component is a green component, and the third color component is a blue component.

[00677] In some embodiments, the second determining unit 1402 is further configured to, when the component comprises a first color component, a second color component and a third color component, determine the number of parts of the identification information about the component of the current slice to be 1 in response to the fact that one part of the identification information about the component is shared by the first color component, the second color component and the third color component of the current slice; or determine the number of parts of the identification information about the component of the current slice to be 2 in response to the fact that one part of the identification information about the component is shared by two color components of the first color component, the second color component and the third color component of the current slice; or determine the number of parts of the identification information about the component of the current slice to be 3 in response to the fact that each of the first color component, the second color component and the third color component of the current slice has a separate part of the identification information about the component.

[00678] In some embodiments, the analysis unit 1401 is further configured to determine first identification information about a component of the current slice by analyzing the bitstream.

[00679] Accordingly, the second determining unit 1402 is further configured to determine that the reversal of the location of the last significant coefficient is applied to each of the first color component, the second color component, and the third color component of the current slice, in response to the fact that the value of the first identification information about the component is the first value.

[00680] In some embodiments, the analysis unit 1401 is further configured to determine the second component identification information and the third component identification information of the current slice by analyzing the bitstream.

[00681] Accordingly, the second determining unit 1402 is further configured to determine that the reversal of the location of the last significant coefficient is applied to each of the two color components of the first color component, the second color component, and the third color component of the current slice, in response to the fact that the value of the second identification information about the component is the first value; and to determine that the reversal of the location of the last significant coefficient is applied to another color component, different from the two color components, of the first color component, the second color component, and the third color component of the current slice, in response to the fact that the value of the third identification information about the component is the first value.

[00682] In some embodiments, the analysis unit 1401 is further configured to determine a fourth component identification information, a fifth component identification information, and a sixth component identification information of the current slice by analyzing the bitstream.

[00686] Accordingly, the second determining unit 1402 is further configured to determine that the reversal of the last significant coefficient is applied to the first color component of the current slice, in response to the fact that the value of the fourth component identification information is the first value; determine that the reversal of the last significant coefficient is applied to the second color component of the current slice, in response to the fact that the value of the fifth component identification information is the first value; and determine that the reversal of the last significant coefficient is applied to the third color component of the current slice, in response to the fact that the value of the sixth component identification information is the first value.

[00684] In some embodiments, the analysis unit 1401 is further configured to obtain information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient by analyzing the bitstream.

[00685] The second determining unit 1402 is further configured to determine a horizontal coordinate of the last significant coefficient according to information about a prefix of the horizontal coordinate of the last significant coefficient and information about a suffix of the horizontal coordinate of the last significant coefficient; determine a vertical coordinate of the last significant coefficient according to information about a prefix of the vertical coordinate of the last significant coefficient and information about a suffix of the vertical coordinate of the last significant coefficient; and determine information about the coordinates of the last significant coefficient of the current block according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00686] In some embodiments, the second determining unit 1402 is further configured to determine information about the coordinates of the last significant coefficient of the current block as a horizontal distance and a vertical distance between the location of the last significant coefficient and the lower right corner of the current block in response to identification information about the component indicating that a reversal of the location of the last significant coefficient has been applied to the component of the current slice.

[00687] Accordingly, the second determining unit 1402 is further configured to determine the width and the height of the current block; obtain a horizontal coordinate of the last significant coefficient by subtracting a horizontal distance between the location of the last significant coefficient and the lower right corner of the current block from the width of the current block; obtain a vertical coordinate of the last significant coefficient by subtracting a vertical distance between the location of the last significant coefficient and the lower right corner of the current block from the height of the current block; and determine the location of the last significant coefficient of the current block according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient.

[00688] In some embodiments, the second determining unit 1402 is further configured to determine information about the coordinates of the last significant coefficient of the current block as a horizontal distance and a vertical distance between the location of the last significant coefficient and the upper left corner of the current block in response to identification information about the component indicating that a change in the location to the inverse of the last significant coefficient is not applied to the component of the current slice; and determine the location of the last significant coefficient of the current block according to the horizontal distance and the vertical distance between the location of the last significant coefficient and the upper left corner of the current block.

[00689] In some embodiments, the analysis unit 1401 is further configured to determine identification information about the resolved last coefficient of the current block by analyzing the bitstream in response to a third identification information about a syntax element indicating that range extension is applied to the current sequence; and to determine coefficients of the current block by decoding coefficients located above the location of the last coefficient, in a given scan order, in response to identification information about the resolved last coefficient indicating that the location of the last coefficient is applied to the current block.

[00690] In some embodiments, the second determining unit 1402 is further configured to determine that the identification information about the last coefficient to be resolved indicates that the location of the last coefficient is applied to the current block in response to the fact that the value of the identification information about the last coefficient to be resolved is a first value; or determine that the identification information about the last coefficient to be resolved indicates that the location of the last coefficient is not applied to the current block in response to the fact that the value of the identification information about the last coefficient to be resolved is a second value.

[00691] In some embodiments, the analysis unit 1401 is further configured to obtain information about a prefix of a horizontal coordinate of the last significant coefficient of the current block, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient by analyzing the bitstream in response to the fact that the value of the identification information about the resolved last coefficient is the second value.

[00692] The second determining unit 1402 is further configured to determine the location of the last significant coefficient according to information about a prefix of a horizontal coordinate of the last significant coefficient, information about a prefix of a vertical coordinate of the last significant coefficient, information about a suffix of a horizontal coordinate of the last significant coefficient, and information about a suffix of a vertical coordinate of the last significant coefficient.

[00693] The analysis unit 1401 is further configured to determine the coefficients of the current block by decoding the coefficients located above the location of the last significant coefficient, in a given scanning order.

[00694] In some embodiments, the location of the last coefficient is the lower right corner of a matrix consisting of all possible non-zero coefficients in the current block. Alternatively, the location of the last coefficient is the last location of all possible non-zero coefficients in a given scan order in the current block.

[00695] In some embodiments, the second determining unit 1402 is further configured to set the location of the last significant coefficient as the location of the last coefficient.

[00696] In some embodiments, the second determining unit 1402 is further configured to determine the width and the height of the transformation block obtained by performing a predetermined operation with respect to the current block; calculate information about the coordinates of the lower right corner of the transformation block according to the width and the height of the transformation block; and determine the location of the last coefficient according to the information about the coordinates of the lower right corner of the transformation block.

[00697] In some embodiments, the specified operation includes at least a zero output operation.

[00698] In some embodiments, the second determining unit 1402 is further configured to determine the location of the last significant coefficient according to the information about the coordinates of the lower right corner of the transform block in response to setting the location of the last significant coefficient as the location of the last coefficient.

[00699] In some embodiments, the analysis unit 1401 is further configured to determine identification information about a default-coded sub-block of the current block by analyzing a bitstream in response to a third identification information about a syntax element indicating that range extension is applied to the current sequence; and decoding coefficients in a sub-block to be decoded in response to the identification information about the default-coded sub-block indicating that the sub-block to be decoded in the current block is default-coded.

[00700] In some embodiments, the analysis unit 1401 is further configured to determine identification information about a coded sub-block for a sub-block to be decoded by analyzing a bitstream in response to identification information about a default coded sub-block indicating that the sub-block to be decoded in the current block is not coded by default; and decoding coefficients in the sub-block to be decoded in response to the fact that the value of the identification information about the coded sub-block is a first value.

[00701] In some embodiments, the second determining unit 1402 is further configured to determine that the identification information about the default-coded sub-block indicates that the sub-block to be decoded in the current block is coded by default, in response to the fact that the value of the identification information about the default-coded sub-block is a first value; or determine that the identification information about the default-coded sub-block indicates that the sub-block to be decoded in the current block is not coded by default, in response to the fact that the value of the identification information about the default-coded sub-block is a second value.

[00702] In some embodiments, the second determining unit 1402 is further configured to determine whether to decode coefficients in a sub-block to be decoded in response to the fact that the value of the identification information about the sub-block to be coded is a first value; or to determine the coefficients in the sub-block to be decoded as zero in response to the fact that the value of the identification information about the sub-block to be coded is a second value.

[00703] In some embodiments, the first value is 1 and the second value is 0.

[00704] It is understood that in an embodiment, a "node" may be a part of a circuit, a part of a processor, a part of a program or software, and/or the like. Of course, a "node" may be a module or may be non-modular. Furthermore, the components in the embodiments may be integrated into one processing part or exist as separate physical nodes, respectively. Alternatively, two or more nodes may be integrated into one node. The integrated node may be implemented in the form of a hardware or software functional node(s).

[00705] When implemented in the form of a software functional module and sold or used as a stand-alone product, the integrated module in this case can also be stored on a computer-readable storage medium. Based on this understanding, the embodiment provides a computer storage medium implemented in the decoder 140. The computer storage medium stores a computer program that, when executed by the second processor, implements the method according to any of the above-described embodiments.

[00706] Based on the composition of the decoder 140 and the computer storage medium, Fig. 15 shows a diagram of the hardware structure of the decoder 140 according to embodiments of the present invention. As shown in Fig. 15, the decoder may include a second communication interface 1501, a second memory 1502 and a second processor 1503. Various components may be interconnected via a second equipment 1504 in the form of buses. It is understood that the second equipment 1504 in the form of buses is configured to implement a connection and communication between these components. In addition to the data bus, the second equipment 1504 in the form of buses may further include a power bus, a control bus and a status signal bus. However, for clarity of description, various buses are designated as the second equipment 1504 in the form of buses in Fig. 15.

[00707] The second communication interface 1501 may be configured to perform sending and receiving a signal when performing sending and receiving information using another external network element.

[00708] The second memory device 1502 is configured to store therein a computer program executed by the second processor 1503.

[00709] The second processor 1503 is configured to execute a computer program for performing the following operations.

[00710] Identification information about a component of the current slice and information about the coordinates of the last significant coefficient of the current block corresponding to the component of the current slice are determined by analyzing the bitstream;

[00711] in response to identification information about a component indicating that a reversal of the location of the last significant coefficient is applied to a component of the current slice, the location of the last significant coefficient of the current block is obtained by performing a calculation with respect to the coordinate information of the last significant coefficient; and

[00712] the coefficients of the current block are determined by decoding the coefficients located above the location of the last significant coefficient, in a given scan order.

[00713] Alternatively, as another embodiment, the second processor 1503 may further be configured to execute a computer program for implementing the method according to any of the above-described embodiments.

[00714] It is understood that the second memory device 1502 is similar to the first memory device 1302 in terms of hardware function, and the second processor 1503 is similar to the first processor 1303 in terms of hardware function, which is not described in detail in this document.

[00715] In an embodiment, a decoder is provided. The decoder may comprise an analysis unit and a second determination unit. Thus, in a scenario of encoding and decoding a video with a high bit depth, a high bit rate, a high quality, or a lossless video, a reasonable mode of obtaining the last significant coefficient is set according to a distribution law of the significant coefficients, thereby reducing the resource consumption caused by encoding in a bit stream and improving the compression efficiency. In addition, since the corresponding color components may be different in the distribution of the significant coefficients, it is possible to accurately control the corresponding mode of obtaining the last significant coefficient for each color component, i.e., by separately controlling whether to apply the reversal technology of the last significant coefficient to each color component, thereby further improving the compression efficiency.

[00716] It should be noted that in the present invention, a term such as "include/comprise", "comprising" or any other variation of this term is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a number of elements not only comprises the elements, but also comprises other element(s) that are not explicitly stated or element(s) inherent in such process, method, article or device. Unless further limited, an element defined by the phrase "comprising..." does not exclude the existence of another identical element in a process, method, article or device that comprises the element.

[00717] The numbering of the embodiments of the present invention is merely for illustration and does not indicate the advantage of one embodiment over another.

[00718] The methods disclosed in the embodiments of the method according to the present invention may be combined with each other as necessary to obtain a new embodiment of the method, provided that the combination does not result in a contradiction.

[00719] The features disclosed in the embodiments of the product according to the present invention may be combined with each other as necessary to obtain a new embodiment of the product, provided that the combination does not result in a contradiction.

[00720] The features disclosed in the embodiments of the method or device according to the present invention may be combined with each other as necessary to obtain a new embodiment of the method or device, provided that the combination does not result in a contradiction.

[00721] The described are only embodiments of the present invention and are not intended to limit the scope of the present invention. Any modification, equivalent replacement and/or the like made within the technical scope of the present invention that may be obvious to a person skilled in the art should be included in the scope of the present invention. Therefore, the scope of the present invention should be determined by the claims.

INDUSTRIAL APPLICABILITY

[00722] In embodiments of the present invention, an encoder determines identification information about a component of a current slice and a location of the last significant coefficient of a current block corresponding to the component of the current slice. The encoder determines information about the coordinates of the last significant coefficient of the current block according to the identification information about the component and the location of the last significant coefficient. The encoder codes the coefficients located above the location of the last significant coefficient in a given scanning order. The encoder provides bit information obtained by encoding, the identification information about the component and the coordinate information of the last significant coefficient to a bitstream. The decoder determines the identification information about the component of the current slice and the coordinate information of the last significant coefficient of the current block corresponding to the component of the current slice by analyzing the bitstream. When the component identification information indicates that the reversal of the last significant coefficient is applied to the component of the current slice, the decoder obtains the location of the last significant coefficient of the current block by performing a calculation with respect to the coordinate information of the last significant coefficient. The decoder determines the coefficients of the current block by decoding the coefficients located above the location of the last significant coefficient in a specified scanning order. Accordingly, in the scenario of encoding and decoding video with a high bit depth, high bit rate, high quality or lossless, a reasonable mode of obtaining the last significant coefficient is set according to the distribution law of significant coefficients, thereby reducing the resource consumption caused by encoding in a bitstream and improving the compression efficiency. In addition, since the corresponding color components may be different in the distribution of significant coefficients, the component identification information can be used to separately control whether to apply the reversal of the last significant coefficient technology to each color component, thereby further improving the compression efficiency.

Claims (66)

1. A decoding method performed by a decoder, wherein the method comprises: determining, by analyzing the bit stream, identification information about the change in the location to the reverse of the last significant coefficient of the current slice and information about the coordinates of the last significant coefficient of the current block of blocks in the current slice; in response to identification information about the reversal of the last significant coefficient indicating that the reversal of the last significant coefficient is applied to the blocks of the current slice, obtaining the location of the last significant coefficient of the current block by performing a calculation with respect to the coordinate information of the last significant coefficient; and determining the coefficients of the current block by decoding the coefficients located before the location of the last significant coefficient, in a given scan order, where the current slice contains a luminance component, a first chroma component, and a second chroma component, wherein determining the identification information about the change in the location to the reverse of the last significant coefficient of the current slice by analyzing the bit stream includes: determining the first identification information about the change in the location to the reverse of the last significant coefficient of the current slice by analyzing the bit stream, wherein the method additionally includes: in response to the fact that the value of the first identification information about the reversal of the last significant coefficient is a first value, determining that the reversal of the last significant coefficient is applied to each of the luminance component, the first chroma component and the second chroma component of the current slice. 2. The method according to paragraph 1, characterized in that it additionally includes: determining first identification information about the syntactic element by analyzing the bit stream; and performing an operation of determining identification information about reversing the position of the last significant coefficient of the current slice by analyzing a bit stream in response to first identification information about a syntax element indicating that reversing the position of the last significant coefficient is permitted for the current sequence, wherein the current sequence contains the current slice. 3. The method according to paragraph 2, characterized in that it additionally includes: determining second identification information about the syntactic element by analyzing the bit stream; determining a third identification information about a syntax element by analyzing a bit stream in response to a second identification information about a syntax element indicating that the version of the extension of the standard is applied to the current sequence; and performing an operation of determining first identification information about a syntax element by analyzing a bit stream in response to third identification information about a syntax element indicating that a range extension has been applied to the current sequence. 4. The method according to paragraph 3, characterized in that it additionally includes: in response to the fact that the value of the third identification information about the syntax element is the first value, determining that the third identification information about the syntax element indicates that a range extension is applied to the current sequence; wherein the range extension is applied to the current sequence, which provides for the following: the current sequence has at least one of the following: high bit depth, high quality, high bit rate, high frame rate, or lossless compression. 5. The method according to paragraph 1, characterized in that it additionally includes: in response to the fact that the value of the identification information of the reversal of the last significant coefficient is a second value, determining that the identification information of the reversal of the last significant coefficient indicates that the reversal of the last significant coefficient is not applied to blocks in the current slice, in response to the last significant coefficient reversal location identification information indicating that the last significant coefficient reversal location is not applied to blocks in the current slice, determining the last significant coefficient location of the current block as equal to the last significant coefficient coordinate information; and determining the coefficients of the current block by decoding the coefficients located before the location of the last significant coefficient, in a given scan order. 6. The method according to paragraph 1, characterized in that it additionally includes: in response to identification information about a reversal of the location of the last significant coefficient indicating that a reversal of the location of the last significant coefficient has been applied to blocks in the current slice, determining information about the coordinates of the last significant coefficient of the current block as a horizontal distance and a vertical distance between the location of the last significant coefficient and the location of the lower right discrete value of the current block, wherein obtaining the location of the last significant coefficient of the current block by performing a calculation with respect to information about the coordinates of the last significant coefficient includes: defining the width and height of the current block; obtaining the horizontal coordinate of the last significant coefficient by subtracting the horizontal distance between the location of the last significant coefficient and the location of the lower right discrete value of the current block from the width of the current block; obtaining the vertical coordinate of the last significant coefficient by subtracting the vertical distance between the location of the last significant coefficient and the location of the lower right discrete value of the current block from the height of the current block; and determining the location of the last significant coefficient of the current block according to the horizontal coordinate of the last significant coefficient and the vertical coordinate of the last significant coefficient. 7. The method according to paragraph 1, characterized in that it additionally includes: in response to identification information about a reversal of the location of the last significant coefficient indicating that a reversal of the location of the last significant coefficient is not applied to blocks in the current slice, determining information about the coordinates of the last significant coefficient of the current block as a horizontal distance and a vertical distance between the location of the last significant coefficient and the location of the upper left discrete value of the current block; and determining the location of the last significant coefficient of the current block according to the horizontal distance and the vertical distance between the location of the last significant coefficient and the location of the upper left discrete value of the current block. 8. The method according to any one of paragraphs 3-4, characterized in that it further comprises: in response to the third identification information about the syntax element indicating that the range extension has been applied to the current sequence, determining identification information about the resolved last coefficient of the current block by analyzing the bit stream; and in response to identification information about the resolved last coefficient indicating that the location of the last coefficient is applied to the current block, determining the coefficients of the current block by decoding the coefficients located before the location of the last coefficient in a given scan order, wherein the method additionally includes: determining the width and height of a transformation block obtained by performing a specified operation on the current block, wherein the specified operation includes at least a zero output operation; calculating information about the coordinates of the lower right discrete value of the transformation block according to the width and height of the transformation block; and determining the location of the last coefficient according to the information about the coordinates of the lower right discrete value of the transformation block. 9. A method of encoding performed by an encoder, wherein the method comprises: determining identification information about the change in the location of the inverse of the last significant coefficient of the current slice and the location of the last significant coefficient of the current block of blocks in the current slice; determining information about the coordinates of the last significant coefficient of the current block according to the identification information about the change in the location to the inverse of the last significant coefficient and the location of the last significant coefficient; and encoding the coefficients located before the location of the last significant coefficient in a given scanning order and providing in a bit stream of bit information obtained by encoding, identification information about changing the location to the reverse of the last significant coefficient and information about the coordinates of the last significant coefficient, where the current slice contains a luminance component, a first chroma component, and a second chroma component, wherein determining the identification information about the change in the location to the reverse of the last significant coefficient of the current slice includes: determining the first identification information about the change in the location to the reverse of the last significant coefficient of the current slice, the method additionally includes: determining a value of the first identification information about the reversal of the last significant coefficient as a first value in response to the fact that the reversal of the last significant coefficient is applied to each of the first chroma component, the second chroma component, and the third chroma component of the current slice. 10. The method according to item 9, characterized in that it additionally includes: before determining the identification information about the change in the location to the reverse of the last significant coefficient of the current slice determining first identifying information about the syntactic element; and performing an operation of determining identification information about reversing the location of the last significant coefficient of the current slice in response to first identification information about a syntax element indicating that reversing the location of the last significant coefficient is permitted for the current sequence, wherein the current sequence contains the current slice. 11. The method according to claim 10, characterized in that it further comprises: before determining the first identification information about the syntactic element determining second identifying information about the syntactic element; determining a third syntactic element identification information in response to the second syntactic element identification information indicating that the extension version of the standard applies to the current sequence; and performing an operation of determining first identification information about a syntax element in response to third identification information about a syntax element indicating that a range extension has been applied to the current sequence. 12. An encoder comprising a first determination node and an encoding node, wherein the first determination node is configured to determine identification information about the change in the location to the reverse of the last significant coefficient of the current slice and the location of the last significant coefficient of the current block of blocks in the current slice, the first determining unit is further configured to determine information about the coordinates of the last significant coefficient of the current block according to the identification information about the change in the location to the reverse of the last significant coefficient and the location of the last significant coefficient; and the coding unit is configured to code the coefficients located before the location of the last significant coefficient in a given scanning order and provide in the bit stream the bit information obtained by coding, identification information about the change in the location to the reverse of the last significant coefficient and information about the coordinates of the last significant coefficient, where the current slice contains a luminance component, a first chroma component, and a second chroma component, the first determining unit is further configured to determine identification information about the reversal of the last significant coefficient of the current slice and to determine a value of the first identification information about the reversal of the last significant coefficient as a first value in response to the reversal of the last significant coefficient being applied to each of the first chroma component, the second chroma component and the third chroma component of the current slice. 13. A decoder comprising an analysis node and a second determination node, wherein the analysis unit is configured to determine, by analyzing the bit stream, identification information about the change in the location to the reverse of the last significant coefficient of the current slice and information about the coordinates of the last significant coefficient of the current block from the blocks in the current slice; the second determining unit is configured to obtain the location of the last significant coefficient of the current block by performing a calculation with respect to the coordinate information of the last significant coefficient in response to the identification information of the reversal of the location of the last significant coefficient indicating that the reversal of the location of the last significant coefficient is applied to the blocks in the current slice; and the analysis unit is additionally configured to determine the coefficients of the current block by decoding the coefficients located before the location of the last significant coefficient, in a given scanning order, where the current slice contains a luminance component, a first chroma component, and a second chroma component, the analysis node is additionally configured to determine identification information about the change in the location to the reverse of the last significant coefficient of the current slice by analyzing the bit stream, the second determining unit is further configured to determine, in response to the fact that the value of the first identification information about the reversal of the last significant coefficient is a first value, that the reversal of the last significant coefficient is applied to each of the luminance component, the first chroma component and the second chroma component of the current slice.