JP7407412B2 - Video encoding device, video encoding method, video encoding program, video decoding device, video decoding method, video decoding program, storage method, and transmission method - Google Patents

Description

The present invention relates to a video encoding device, a video encoding method, a video encoding program, a video decoding device, a video decoding method, a video decoding program, a storage method, and a transmission method .

In image encoding and decoding, an image to be processed is divided into blocks, each of which is a set of a predetermined number of pixels, and processing is performed on a block-by-block basis. Encoding efficiency is improved by dividing into appropriate blocks and appropriately setting intra-frame prediction (intra prediction) and inter-frame prediction (inter prediction).

In the encoding and decoding of moving images, the encoding efficiency is improved by inter prediction, which predicts from encoded and decoded pictures. Patent Document 1 describes a technique that applies affine transformation during inter prediction. In moving images, it is not uncommon for objects to undergo deformation such as enlargement, reduction, rotation, etc., and by applying the technique of Patent Document 1, efficient encoding becomes possible.

Japanese Patent Application Publication No. 9-172644

However, since the technique disclosed in Patent Document 1 involves image conversion, there is a problem that the processing load is large. In view of the above problems, the present invention provides a low-load and efficient encoding technique.

In order to solve the above problems, a video encoding device according to an aspect of the present invention includes a history prediction candidate list updating unit that adds motion information of an encoded block to the end of a history prediction motion vector candidate list; A spatial motion information candidate derivation unit that derives a spatial motion information candidate from the motion information of a block spatially close to the target block and adds it to a predicted motion vector candidate list; a temporal motion information candidate derivation unit that derives a temporal motion information candidate from the information and adds it to the predicted motion vector candidate list; and a temporal motion information candidate derivation unit that derives a historical motion information candidate from the historical predicted motion vector candidate list and adds it to the predicted motion vector candidate list. a historical motion information candidate deriving section for adding historical motion information candidates, the historical motion information candidate deriving section does not compare motion information with elements of the historical motion vector predictor candidate list, and adds historical motion information candidates from the beginning of the historical motion vector predictor candidate list. The historical motion information candidates are derived by sequential reference and added to the predicted motion vector candidate list.
Further, a video encoding method according to an aspect of the present invention includes a step of updating the history prediction candidate list of adding motion information of the encoded block to the end of the history prediction motion vector candidate list, and A spatial motion information candidate derivation step of deriving spatial motion information candidates from the motion information of adjacent blocks and adding them to a predicted motion vector candidate list; and a temporal motion information candidate deriving step from the motion information of blocks temporally adjacent to the block to be encoded. a step of deriving temporal motion information candidates and adding them to the predicted motion vector candidate list; and a step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list. deriving step, and in the historical motion information candidate deriving step, the motion information is not compared with the elements of the historical motion vector predictor candidate list, and the historical motion vector predictor candidate list is sequentially referred to from the top of the predicted motion vector candidate list. A historical motion information candidate is derived and added to the predicted motion vector candidate list.
Further, a video encoding program according to an aspect of the present invention includes a step of updating the history prediction candidate list of adding motion information of the encoded block to the end of the history prediction motion vector candidate list; A spatial motion information candidate derivation step that derives spatial motion information candidates from the motion information of blocks that are spatially close to each other and adds them to a predicted motion vector candidate list; a temporal motion information candidate deriving step of deriving a motion information candidate and adding it to the predicted motion vector candidate list; and a history motion information candidate deriving from the historical predicted motion vector candidate list and adding it to the predicted motion vector candidate list. a motion information candidate deriving step, wherein in the history motion information candidate deriving step, the motion information is not compared with the elements of the predicted motion vector candidate list; The historical motion information candidates are derived by sequentially referring to the motion vector predictor candidate list from the beginning, and added to the motion vector predictor candidate list.
Further, a video decoding device according to an aspect of the present invention includes a history prediction candidate list updating unit that adds motion information of a decoded block to the end of a history prediction motion vector candidate list, and a block spatially adjacent to the block to be decoded. a spatial motion information candidate derivation unit that derives a spatial motion information candidate from the motion information of the block and adds it to a predicted motion vector candidate list; a temporal motion information candidate deriving unit that adds to the predicted motion vector candidate list; a historical motion information candidate deriving unit that derives a historical motion information candidate from the historical predicted motion vector candidate list and adds it to the predicted motion vector candidate list; The historical motion information candidate deriving unit sequentially refers to the historical motion vector predictor candidate list from the beginning without comparing the motion information with the elements of the predicted motion vector candidate list to determine the historical motion information candidates. The motion vector predictor is derived and added to the predicted motion vector candidate list.
Further, a moving image decoding method according to an aspect of the present invention includes a step of updating a history prediction candidate list of adding motion information of a decoded block to the end of a history prediction motion vector candidate list; a spatial motion information candidate deriving step of deriving a spatial motion information candidate from the motion information of and adding it to a predicted motion vector candidate list; deriving a temporal motion information candidate from the motion information of a block temporally close to the decoding target block; a step of deriving temporal motion information candidates to be added to the predicted motion vector candidate list; a step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list; In the historical motion information candidate derivation step, the historical motion vector candidate list is sequentially referred to from the beginning of the historical motion vector predictor candidate list without comparing the motion information with the elements of the predicted motion vector candidate list. is derived and added to the motion vector predictor candidate list.
Further, a moving image decoding program according to an aspect of the present invention includes a step of updating the history prediction candidate list of adding motion information of the decoded block to the end of the history prediction motion vector candidate list, and a step of updating the history prediction candidate list to add motion information of the decoded block to the end of the history prediction motion vector candidate list; A spatial motion information candidate derivation step of deriving spatial motion information candidates from motion information of adjacent blocks and adding them to a predicted motion vector candidate list; and a temporal motion information candidate deriving step from motion information of blocks temporally adjacent to the block to be decoded. a temporal motion information candidate derivation step of deriving temporal motion information candidates and adding them to the predicted motion vector candidate list, and deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list. A moving image decoding program for executing the steps, wherein in the step of deriving historical motion information candidates, the motion information is not compared with elements of the predicted motion vector candidate list, and the motion information is not compared with the elements of the predicted motion vector candidate list. The historical motion information candidates are derived from the beginning of the motion vector predictor list and added to the motion vector predictor candidate list.
Further, a data structure according to an aspect of the present invention is that of encoded data used in a computer including a history prediction candidate list update unit, a spatial motion information candidate derivation unit, a temporal motion information candidate derivation unit, and a history motion information candidate derivation unit. The data structure is such that the computer adds the motion information of the encoded block to the end of the history prediction candidate list, and the spatial motion information candidate derivation unit adds the motion information of the encoded block to the end of the history prediction candidate list, and the spatial motion information candidate derivation unit A spatial motion information candidate is derived from the motion information of a block spatially adjacent to the target block, and added to a predicted motion vector candidate list, and the temporal motion information candidate derivation unit derives a spatial motion information candidate from the motion information of a block spatially adjacent to the target block. A temporal motion information candidate is derived from the motion information of and added to the predicted motion vector candidate list, and the historical motion information candidate derivation unit does not compare the motion information with the elements of the predicted motion vector candidate list, and adds the temporal motion information candidate to the predicted motion vector candidate list. The historical motion information candidates are derived from the historical predicted motion vector candidate list by sequentially referring to the historical predicted motion vector candidate list from the beginning.

According to the present invention, highly efficient image encoding/decoding processing can be realized with low load.

FIG. 1 is a block diagram of an image encoding device according to an embodiment of the present invention. FIG. 1 is a block diagram of an image decoding device according to an embodiment of the present invention. 12 is a flowchart for explaining the operation of dividing a tree block. FIG. 3 is a diagram showing how an input image is divided into tree blocks. FIG. 2 is a diagram illustrating z-scan. FIG. 3 is a diagram showing a divided shape of blocks. 3 is a flowchart for explaining the operation of dividing a block into four parts. 12 is a flowchart for explaining the operation of dividing a block into two or three. This is a syntax for expressing the shape of block division. FIG. 2 is a diagram for explaining intra prediction. FIG. 3 is a diagram for explaining a reference block for inter prediction. This is a syntax for expressing a coded block prediction mode. It is a figure which shows the correspondence of the syntax element and mode regarding inter prediction. FIG. 3 is a diagram for explaining affine transformation motion compensation for two control points. FIG. 3 is a diagram for explaining affine transformation motion compensation for three control points. 2 is a block diagram of a detailed configuration of an inter prediction unit 201 in FIG. 1. FIG. 17 is a block diagram of a detailed configuration of the normal predicted motion vector mode deriving unit 301 in FIG. 16. FIG. 17 is a block diagram of a detailed configuration of the normal merge mode deriving unit 302 in FIG. 16. FIG. 17 is a flowchart for explaining normal predicted motion vector mode derivation processing by the normal predicted motion vector mode derivation unit 301 of FIG. 16. FIG. 3 is a flowchart illustrating the processing procedure of normal predicted motion vector mode derivation processing. 3 is a flowchart illustrating the procedure of normal merge mode derivation processing. 3 is a block diagram of a detailed configuration of an inter prediction unit 203 in FIG. 2. FIG. 23 is a block diagram of a detailed configuration of a normal predicted motion vector mode deriving unit 301 in FIG. 22. FIG. 17 is a block diagram of a detailed configuration of the normal merge mode deriving unit 302 in FIG. 16. FIG. 23 is a flowchart for explaining normal predicted motion vector mode derivation processing by the normal predicted motion vector mode derivation unit 301 of FIG. 22. FIG. 17 is a block diagram of a detailed configuration of a sub-block predicted motion vector mode deriving unit 303 in FIG. 16. FIG. 23 is a block diagram of a detailed configuration of a sub-block predicted motion vector mode deriving unit 403 in FIG. 22. FIG. 17 is a block diagram of a detailed configuration of a sub-block merge mode deriving unit 304 in FIG. 16. FIG. 23 is a block diagram of a detailed configuration of a sub-block merge mode deriving unit 404 in FIG. 22. FIG. FIG. 3 is a diagram illustrating derivation of affine inheritance predicted motion vector candidates. FIG. 3 is a diagram illustrating derivation of affine construction predicted motion vector candidates. FIG. 2 is a diagram illustrating derivation of affine inheritance merge candidates. FIG. 3 is a diagram illustrating derivation of affine construction merge candidates. 12 is a flowchart for deriving affine inheritance predicted motion vector candidates. 12 is a flowchart of deriving affine construction predicted motion vector candidates. 3 is a flowchart of deriving affine inheritance merge candidates. It is a flowchart of affine construction merging candidate derivation. 12 is a flowchart illustrating a historical predicted motion vector candidate list initialization/update processing procedure. 12 is a flowchart of a same element confirmation process in a history predicted motion vector candidate derivation process. 12 is a flowchart of an element shift processing procedure in a history predicted motion vector candidate derivation processing procedure. 12 is a flowchart illustrating a historical predicted motion vector candidate derivation process procedure. 3 is a flowchart illustrating a history merging candidate derivation processing procedure. FIG. 3 is a diagram illustrating an example of a history predicted motion vector candidate list update process. 12 is a flowchart for explaining the operation of the sub-block time merging candidate deriving unit 381. 3 is a flowchart for explaining a process for deriving adjacent motion information of a block. 3 is a flowchart for explaining processing for deriving a temporal motion vector. It is a flow chart for explaining derivation of inter prediction information. 12 is a flowchart for explaining a process for deriving sub-block motion information. FIG. 3 is a diagram for explaining the temporal context of pictures. 12 is a flowchart for explaining a process of deriving a temporally predicted motion vector candidate in a normal predicted motion vector mode derivation unit 301. FIG. 12 is a flowchart for explaining ColPic derivation processing in the temporal prediction motion vector candidate derivation processing in the normal prediction motion vector mode derivation unit 301. 12 is a flowchart for explaining the process of deriving ColPic encoding information in the process of deriving a temporally predicted motion vector candidate in the normal predicted motion vector mode deriving unit 301. FIG. It is a flow chart for explaining derivation processing of inter prediction information. It is a flowchart which shows the derivation process of the inter prediction information of a coding block when the inter prediction mode of coding block colCb is bi-prediction (Pred_BI). 3 is a flowchart for explaining a motion vector scaling calculation process procedure. 12 is a flowchart for explaining a time merge candidate derivation process. FIG. 7 is a diagram for explaining motion compensated prediction in the case where the L0 reference picture (RefL0Pic) is at a time earlier than the processing target picture (CurPic) in L0 prediction. FIG. 7 is a diagram for explaining motion compensated prediction in a case where a reference picture for L0 prediction is at a later time than a processing target picture in L0 prediction. FIG. 7 is a diagram for explaining motion compensated prediction in the case where the reference picture for L0 prediction is at a time before the picture to be processed and the reference picture for L1 prediction is at a time after the picture to be processed in bi-prediction. . FIG. 7 is a diagram for explaining a prediction direction of motion compensation prediction when bi-prediction is performed and a reference picture for L0 prediction and a reference picture for L1 prediction are at a time earlier than a processing target picture. FIG. 7 is a diagram for explaining a prediction direction of motion compensation prediction when bi-prediction is used and a reference picture for L0 prediction and a reference picture for L1 prediction are located at a later time than the processing target picture. 3 is a flowchart illustrating an average merging candidate derivation processing procedure. 3 is a table showing information regarding merge difference motion vectors. FIG. 3 is a diagram illustrating derivation of a merge difference motion vector. The procedure for deriving historical predicted motion vector candidates is shown below when the historical predicted motion vector candidate list is used while sequentially referring to the newly added motion information from old motion information, and the same candidate deletion process is not performed. It is a flowchart explaining. 12 is a flowchart of an element shift/addition processing procedure for a historical predicted motion vector candidate list. We will explain the history merging candidate derivation processing procedure when the history predicted motion vector candidate list is used while sequentially referring to the newly added motion information from the old motion information, and the same candidate deletion processing is not performed. It is a flowchart. FIG. 3 is a diagram for explaining the structure of a historical predicted motion vector candidate list. FIG. 7 is a diagram for explaining how a leading element is deleted when adding to a history predicted motion vector candidate list. FIG. 6 is a diagram for explaining how each element is shifted within the list when added to the history predicted motion vector candidate list. FIG. 7 is a diagram for explaining how a new element is added when adding a new element to a history predicted motion vector candidate list. FIG. 3 is a diagram for explaining the reference order of a historical predicted motion vector candidate list. FIG. 3 is a diagram for explaining the reference order of a historical predicted motion vector candidate list. 12 is a flowchart illustrating a procedure for deriving historical predicted motion vector candidates in a case where the historical predicted motion vector candidate list is used while being referred to in an order opposite to the storage order, and the same candidate deletion process is not performed. 12 is a flowchart illustrating a historical predicted motion vector candidate derivation process in a case where the same candidate deletion process is performed by using the historical predicted motion vector candidate list while referring to the historical predicted motion vector candidate list in the reverse order to the storage order.

The technology and technical terms used in this embodiment will be defined.

<Tree block>
In the embodiment, an image to be encoded/decoded is equally divided into predetermined sizes. This unit is defined as a tree block. As shown in FIG. 4, in this embodiment, the size of the tree block is set to 128x128 pixels, but the size of the tree block is not limited to this, and may be set to any size. Tree blocks to be processed (corresponding to encoding targets in encoding processing and decoding targets in decoding processing) are switched in raster scan order, that is, from left to right and from top to bottom. The interior of each treeblock can be further recursively divided. A block to be encoded/decoded after tree block division is defined as an encoded block. Furthermore, tree blocks and encoded blocks are collectively defined as blocks. Efficient encoding becomes possible by performing appropriate block division. The size of the tree block may be a fixed value determined in advance by the encoding device and the decoding device, or a configuration may be adopted in which the size of the tree block determined by the encoding device is transmitted to the decoding device.

<Prediction mode>
Processed images of the target image are processed in units of encoded blocks (in the encoding process, signals that have been encoded are used as decoded images, image signals, tree blocks, blocks, encoded blocks, etc.; in the decoding process, Intra prediction (MODE_INTRA) that makes predictions from the surrounding image signals of decoded images, image signals, tree blocks, blocks, encoded blocks, etc.), and Inter prediction that makes predictions from the image signals of processed images. Switch (MODE_INTER). A mode for identifying this intra prediction (MODE_INTRA) and inter prediction (MODE_INTER) is defined as a prediction mode (PredMode). The prediction mode (PredMode) has intra prediction (MODE_INTRA) or inter prediction (MODE_INTER) as a value.

<Inter prediction>
In inter prediction in which prediction is performed from an image signal of a processed image, a plurality of processed images can be used as reference pictures. In order to manage a plurality of reference pictures, two types of reference lists, L0 (reference list 0) and L1 (reference list 1), are defined, and reference pictures are specified using each reference index. L0 prediction (Pred_L0) is available for P slices. In the B slice, L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI) can be used. L0 prediction (Pred_L0) is inter prediction that refers to a reference picture managed in L0, and L1 prediction (Pred_L1) is inter prediction that refers to a reference picture managed in L1. Bi-prediction (Pred_BI) is inter prediction in which both L0 prediction and L1 prediction are performed and refers to one reference picture managed in each of L0 and L1. Information specifying L0 prediction, L1 prediction, and bi-prediction is defined as inter prediction mode. In the subsequent processing, it is assumed that constants and variables whose outputs have the subscript LX are processed for each L0 and L1.

<Predicted motion vector mode>
The predicted motion vector mode is a mode in which an index for specifying a predicted motion vector, a differential motion vector, an inter prediction mode, and a reference index are transmitted, and inter prediction information of a block to be processed is determined. The predicted motion vector is a predicted motion vector candidate derived from a processed block adjacent to the target block, or a block belonging to the processed image that is located at the same position as the target block (nearby), and a predicted motion vector Derived from the index to identify the vector.

<Merge mode>
Merge mode is a processed block adjacent to the target block, or a block belonging to the processed image located at the same position as the target block or in the vicinity (nearby) of the target block, without transmitting the differential motion vector or reference index. This is a mode in which inter prediction information of the block to be processed is derived from inter prediction information of the block to be processed.

A processed block adjacent to the target block and inter prediction information of the processed block are defined as spatial merging candidates. A block belonging to the processed image that is located at the same position as the target block or in its vicinity (nearby), and inter prediction information derived from the inter prediction information of the block are defined as temporal merging candidates. Each merging candidate is registered in a merging candidate list, and a merging candidate to be used in prediction of a block to be processed is specified by a merging index.

<Adjacent block>
FIG. 11 is a diagram illustrating reference blocks that are referred to in order to derive inter prediction information in the motion vector predictor mode and the merge mode. A0, A1, A2, B0, B1, B2, and B3 are processed blocks adjacent to the target block. T0 is a block belonging to the processed image, and is a block located at or near the same position as the encoding block to be processed in the image to be processed.

A1 and A2 are blocks located on the left side of the encoding block to be processed and adjacent to the encoding block to be processed. B1 and B3 are blocks located above the encoding block to be processed and adjacent to the encoding block to be processed. A0, B0, and B2 are blocks located at the lower left, upper right, and upper left of the encoding block to be processed, respectively.

Details of how adjacent blocks are handled in the motion vector predictor mode and merge mode will be described later.

<Affine transformation motion compensation>
In affine transformation motion compensation, a coded block is divided into subblocks of a predetermined unit, and a motion vector is individually set for each subblock to perform motion compensation. The motion vector of each sub-block is derived from the inter prediction information of a processed block adjacent to the target block, or a block belonging to the processed image that is located at the same position as the target block or in the vicinity (nearby). Derived based on two or more control points. In this embodiment, the size of the sub-block is 4x4 pixels, but the size of the sub-block is not limited to this, and the motion vector may be derived on a pixel-by-pixel basis.

FIG. 14 shows an example of affine transformation motion compensation when there are two control points. In this case, since the two control points have two parameters, a horizontal component and a vertical component, the affine transformation when there are two control points is called a four-parameter affine transformation. CP1 and CP2 in FIG. 14 are control points. FIG. 15 shows an example of affine transformation motion compensation when there are three control points. In this case, since the three control points have two parameters, a horizontal component and a vertical component, the affine transformation when there are three control points is called a six-parameter affine transformation. CP1, CP2, and CP3 in FIG. 15 are control points.

Affine transform motion compensation can be used in both predicted motion vector mode and merge mode. A mode in which affine transform motion compensation is applied in predicted motion vector mode is defined as sub-block predicted motion vector mode, and a mode in which affine transform motion compensation is applied in merge mode is defined as sub-block merge mode.

<Syntax of inter prediction>
The syntax regarding inter prediction will be explained using FIGS. 12 and 13. merge_flag in FIG. 12 is a flag indicating whether the encoding block to be processed is set to merge mode or predicted motion vector mode. merge_affine_flag is a flag indicating whether or not sub-block merge mode is applied to the encoded block to be processed in merge mode. inter_affine_flag is a flag indicating whether or not to apply the sub-block motion vector predictor mode to the encoding block to be processed in the motion vector predictor mode. cu_affine_type_flag is a flag for determining the number of control points in sub-block predicted motion vector mode. FIG. 13 shows the values of each syntax element and the corresponding prediction method. merge_flag=1, merge_affine_flag=0 corresponds to normal merge mode, which is a merge mode that is not a subblock merge. merge_flag=1,merge_affine_flag=1 corresponds to subblock merge mode. merge_flag=0, inter_affine_flag=0 corresponds to the normal predicted motion vector mode, which is a predicted motion vector merge that is not a sub-block predicted motion vector mode. merge_flag=0, inter_affine_flag=1 corresponds to sub-block predicted motion vector mode. If merge_flag=0, inter_affine_flag=1, cu_affine_type_flag is further transmitted and the number of control points is determined.

<POC>
POC (Picture Order Count) is a variable associated with pictures to be encoded, and is set to a value that increases by 1 in the output order of pictures. Depending on the POC value, it is possible to determine whether the pictures are the same, to determine the context between the pictures in the output order, and to derive the distance between the pictures. For example, if two pictures have the same POC value, it can be determined that they are the same picture. When two pictures have different POC values, it can be determined that the picture with the smaller POC value is the one to be output first, and the difference in POC between the two pictures determines the distance between the pictures in the time axis direction. show.

(First embodiment)
An image encoding device 100 and an image decoding device 200 according to a first embodiment of the present invention will be described.

FIG. 1 is a block diagram of an image encoding device 100 according to the first embodiment. The video encoding device of the embodiment includes an image encoding device 100, a block division section 101, an inter prediction section 102, an intra prediction section 103, a decoded image memory 104, a prediction method determination section 105, a residual signal generation section 106, It includes an orthogonal transformation/quantization section 107, a bit string encoding section 108, an inverse quantization/inverse orthogonal transformation section 109, a decoded image signal superimposition section 110, and an encoded information storage memory 111.

The block dividing unit 101 recursively divides an input image to generate encoded blocks. The block division unit 101 includes a 4-division unit that divides the block to be divided into horizontal and vertical directions, and a 2-3 division unit to divide the block to be divided into either the horizontal direction or the vertical direction. . The generated image signal of the encoding block to be processed is supplied to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106. Further, information indicating the determined recursive partitioning structure is supplied to the bit string encoding unit 108. The detailed operation of block dividing section 101 will be described later.

The inter prediction unit 102 performs inter prediction of the encoding block to be processed. A plurality of inter prediction information candidates are derived from the inter prediction information stored in the encoded information storage memory and the decoded image signal stored in the decoded image memory 104, and a suitable inter prediction is performed from among the plurality of candidates. A mode is selected, and the selected inter prediction mode and a predicted image signal according to the selected inter prediction mode are supplied to the prediction method determining unit 105. The detailed configuration and operation of the inter prediction unit 102 will be described later.

The intra prediction unit 103 performs intra prediction of the processing target coded block. A predicted image signal is generated by intra prediction from the decoded image signal stored in the decoded image memory 104, a suitable intra prediction mode is selected from a plurality of intra prediction modes, and the selected intra prediction mode and A predicted image signal according to the selected intra prediction mode is supplied to the prediction method determining unit 105. FIG. 10 shows an example of intra prediction. FIG. 10A shows the correspondence between the prediction direction of intra prediction and the intra prediction mode number. For example, intra-prediction mode 50 generates an intra-predicted image by copying pixels in the vertical direction. Intra prediction mode 1 is a DC mode, and is a mode in which all pixel values of the processing target block are the average value of reference pixels. Intra prediction mode 0 is a Planar mode, which is a mode in which a two-dimensional intra prediction image is created from reference pixels in the vertical and horizontal directions. FIG. 10(b) is an example of generating an intra-predicted image in intra-prediction mode 40. The value of the reference pixel in the direction indicated by the intra prediction mode is copied to each pixel of the block to be processed. If the reference pixel in intra prediction mode is not at an integer position, the reference pixel value is determined by interpolation from reference pixel values at surrounding integer positions.

The decoded image memory 104 stores the decoded image generated by the decoded image signal superimposing section 110. The decoded image stored in the decoded image memory is supplied to the inter prediction unit 102 and the intra prediction unit 103.

The prediction method determining unit 105 evaluates each prediction using the encoding information, the amount of code of the residual signal, the amount of distortion between the predicted image signal and the image signal to be processed, etc., and determines the optimal prediction. Decide on the mode (inter prediction or intra prediction). In the case of the inter-prediction merge mode, the encoding information of the merge index and information indicating whether or not the sub-block merge mode is selected (sub-block merge flag) is supplied to the bit string encoding unit 108, and the encoding information of the merge index and the information indicating whether or not the sub-block merge mode is selected (sub-block merge flag) is supplied to the bit string encoding unit 108, and In this case, the bit string encoding unit 108 encodes encoding information such as inter prediction mode, predicted motion vector index, reference index of L0 and L1, differential motion vector, and information indicating whether or not it is subblock mode (subblock predicted motion vector flag). supply to. The determined encoded information is supplied to the encoded information storage memory 111.

The residual signal generation unit 106 generates a residual signal by subtracting the predicted image signal from the image signal to be processed, and supplies it to the orthogonal transformation/quantization unit 107 .

The orthogonal transformation/quantization unit 107 performs orthogonal transformation and quantization on the residual signal according to the quantization parameter, generates an orthogonal transformed/quantized residual signal, and performs orthogonal transformation and quantization on the residual signal, and performs orthogonal transformation and quantization on the residual signal. It is supplied to the conversion/inverse orthogonal transform section 109.

The bit string encoding unit 108 encodes encoding information according to the prediction method determined by the prediction method determination unit 105 for each encoding block, in addition to information in sequence, picture, slice, and encoding block units. Specifically, the prediction mode PredMode for each encoded block, the division mode PartMode, in the case of inter prediction (PRED_INTER), a flag to determine whether it is merge mode or not, the subblock merge flag, in the case of merge mode, the merge index, merge If not, encode the encoding information such as inter prediction mode, predicted motion vector index, differential motion vector information, sub-block predicted motion vector flag, etc. according to the specified syntax rules described later, and generate the first encoded bit string. do. Further, the bit string encoding unit 108 generates a second encoded bit string by entropy encoding the orthogonally transformed and quantized residual signal according to a prescribed syntax rule. The first encoded bit string and the second encoded bit string are multiplexed according to a prescribed syntax rule, and a bit stream is output.

The inverse quantization/inverse orthogonal transform unit 109 performs inverse quantization and inverse orthogonal transform on the orthogonally transformed/quantized residual signal supplied from the orthogonal transform/quantization unit 107 to calculate a residual signal, and decodes the residual signal. The image signal is supplied to the image signal superimposing section 110.

The decoded image signal superimposing unit 110 superimposes the predicted image signal determined by the prediction method determining unit 105 and the residual signal that has been inversely quantized and inversely orthogonally transformed in the inversely quantized and inversely orthogonally transformed unit 109 to generate a decoded image. is generated and stored in the decoded image memory 104. Note that the decoded image may be stored in the decoded image memory 104 after being subjected to filtering processing to reduce distortion such as block distortion caused by encoding.

The encoding information storage memory 111 stores encoding information such as a prediction mode (inter prediction or intra prediction) determined by the prediction method determining unit 105. In the case of inter prediction, the coding information stored in the coding information storage memory 111 includes the determined motion vector, reference list, and reference index, and in the case of inter prediction merging mode, the merging index, subblock merging mode, etc. Encoding information of information indicating whether or not to merge (sub-block merge flag), in the case of inter-prediction predicted motion vector mode, inter-prediction mode, predicted motion vector index, L0, L1 reference index, differential motion vector, sub-block mode? In the case of intra prediction, information indicating whether or not the prediction is made (sub-block predicted motion vector flag), the determined intra prediction mode, etc. Construction of the history candidate list managed by the encoded information storage memory 111 will be described later.

FIG. 2 is a block diagram showing the configuration of a video decoding device according to an embodiment of the present invention, which corresponds to the video encoding device of FIG. The video decoding device of the embodiment includes a bit string decoding unit 201, a block dividing unit 202, an inter prediction unit 203, an intra prediction unit 204, an encoded information storage memory 205, an inverse quantization/inverse orthogonal transform unit 206, and a decoded image signal. It includes a superimposing section 207 and a decoded image memory 208.

The decoding process of the video decoding device in FIG. 2 corresponds to the decoding process provided inside the video encoding device in FIG. - Each configuration of the inverse orthogonal transform unit 206, decoded image signal superimposition unit 207, and decoded image memory 208 is the inverse quantization/inverse orthogonal transform unit 109, decoded image signal superimposition unit 110, It has functions corresponding to the configurations of encoded information storage memory 111 and decoded image memory 104, respectively.

The bitstream supplied to the bitstream decoding unit 201 is separated according to prescribed syntax rules. The separated first encoded bit string is decoded to obtain information in sequence, picture, slice, encoded block units, and encoding information in encoded block units. Specifically, the prediction mode PredMode determines whether it is inter prediction (PRED_INTER) or intra prediction (PRED_INTRA) for each encoded block, the division mode PartMode, and the flag that determines whether it is merge mode in the case of inter prediction (PRED_INTER). , in the case of merge mode, coding information regarding the merge index, sub-block merge flag, and in the case of predicted motion vector mode, inter prediction mode, predicted motion vector index, differential motion vector, sub-block predicted motion vector flag, etc., as described below. The coded information is decoded according to the syntax rules of , and the coded information is supplied to the inter prediction unit 203 or the intra prediction unit 204 and the coded information storage memory 205. The separated second encoded bit string is decoded to calculate an orthogonally transformed and quantized residual signal, and the orthogonally transformed and quantized residual signal is supplied to the inverse quantization and inverse orthogonal transform section 206 .

When the prediction mode PredMode of the encoding block to be processed is inter prediction (PRED_INTER) and the predicted motion vector mode, the inter prediction unit 203 calculates the code of the already decoded image signal stored in the encoding information storage memory 205. Using this information, multiple motion vector predictor candidates are derived and registered in a motion vector predictor candidate list (described later), and bit string decoding is performed from among the multiple motion vector predictor candidates registered in the motion vector predictor candidate list. The bit string decoding section 201 selects a predicted motion vector according to the decoded and supplied predicted motion vector index, calculates a motion vector from the decoded difference vector and the selected motion vector predictor, and performs other encoding. It is stored in the encoded information storage memory 205 together with the information. The encoding information of the encoded block supplied and stored here includes flags predFlagL0[xP][yP] and predFlagL1[xP] indicating whether to use prediction mode PredMode, division mode PartMode, L0 prediction, and L1 prediction. [yP], reference index of L0, L1 refIdxL0[xP][yP], refIdxL1[xP][yP], motion vector of L0, L1 mvL0[xP][yP], mvL1[xP][yP], etc. . Here, xP and yP are indices indicating the position of the upper left pixel of the encoded block within the picture. If the prediction mode PredMode is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), the flag predFlagL0 indicating whether to use L0 prediction is 1, and the flag predFlagL1 indicating whether to use L1 prediction is 0. When the inter prediction mode is L1 prediction (Pred_L1), the flag predFlagL0 indicating whether to use L0 prediction is 0, and the flag predFlagL1 indicating whether to use L1 prediction is 1. When the inter prediction mode is bi-prediction (Pred_BI), the flag predFlagL0 indicating whether to use L0 prediction and the flag predFlagL1 indicating whether to use L1 prediction are both 1. Furthermore, when the prediction mode PredMode of the encoded block to be processed is inter prediction (PRED_INTER) and is in the merge mode, merge candidates are derived. Using the encoding information of the already decoded encoded blocks stored in the encoding information storage memory 205, a plurality of merging candidates are derived and registered in a merging candidate list to be described later. A flag indicating whether or not to select a merging candidate corresponding to a merging index decoded and supplied by the bit string decoding unit 201 from among a plurality of merging candidates, and to use L0 prediction and L1 prediction of the selected merging candidate. predFlagL0[xP][yP], predFlagL1[xP][yP], reference index of L0, L1 refIdxL0[xP][yP], refIdxL1[xP][yP], motion vector of L0, L1 mvL0[xP][yP ], mvL1[xP][yP] and the like are stored in the encoded information storage memory 205. Here, xP and yP are indices indicating the position of the upper left pixel of the encoded block within the picture. The detailed configuration and operation of the inter prediction unit will be described later.

The intra prediction unit 204 performs intra prediction when the prediction mode PredMode of the encoding block to be processed is intra prediction (PRED_INTRA). The encoded information decoded by the bit string decoding unit 201 includes an intra prediction mode, and according to the intra prediction mode, a predicted image signal is generated by intra prediction from the decoded image signal stored in the decoded image memory 208. is generated, and the predicted image signal is supplied to the decoded image signal superimposition unit 207. Since the intra prediction unit 204 corresponds to the intra prediction unit 103 of the image encoding device 100, it performs the same processing as the intra prediction unit 103.

The inverse quantization/inverse orthogonal transform unit 206 performs inverse orthogonal transform and inverse quantization on the orthogonally transformed/quantized residual signal decoded by the bit string decoding unit 201, and Obtain the residual signal.

The decoded image signal superimposition unit 207 performs inverse orthogonal transformation and inverse quantization and inverse orthogonal transformation on the predicted image signal that has been inter-predicted by the inter-prediction unit 203 or the predicted image signal that has been intra-predicted in the intra-prediction unit 204 . By superimposing the dequantized residual signal, the decoded image signal is decoded and stored in the decoded image memory 208. When storing the image in the decoded image memory 208, the decoded image may be stored in the decoded image memory 208 after being subjected to filtering processing to reduce block distortion caused by encoding.

Next, the operation of block dividing section 101 in image encoding device 100 will be explained. FIG. 3 is a flowchart showing operations for dividing an image into tree blocks and further dividing each tree block. First, an input image is divided into tree blocks of a predetermined size (step S1001). Each tree block is scanned in a predetermined order, that is, in raster scan order (step S1002), and the inside of the tree block to be processed is divided (step S1003).

FIG. 7 is a flowchart showing detailed operations of the division process in step S1003. First, it is determined whether or not the block to be processed is divided into four (step S1101).

If it is determined that the block to be processed is to be divided into four, the block to be processed is divided into four (step S1102). Each block obtained by dividing the block to be processed is scanned in the Z-scan order, that is, in the order of upper left, upper right, lower left, and lower right (step S1103). FIG. 5 is an example of the Z scan order, and 601 in FIG. 6 is an example in which the block to be processed is divided into four. Numbers 0 to 3 in 601 in FIG. 6 indicate the order of processing. The flowchart of FIG. 7 is then recursively called for each block divided in step S1101.

If it is determined that the block to be processed is not to be divided into four, it is divided into 2-3 (step S1105).

FIG. 8 is a flowchart showing the detailed operation of the 2-3 division process in step S1105. First, it is determined whether the block to be processed is to be divided into 2-3 parts, that is, whether to divide it into 2 or 3 (step S1201).

If it is not determined that the block to be processed is to be divided into 2-3, that is, if it is determined not to be divided, the division is ended (step S1211) and the process returns to the upper layer block.

If it is determined that the block to be processed is to be divided into 2-3, it is further determined whether or not to divide the block to be processed into 2 (step S1202).

If it is determined that the block to be processed is to be divided into two, it is determined whether or not to divide the block to be processed in the vertical direction (step S1203), and based on the result, the block to be processed is divided in the vertical direction (step S1204). Alternatively, the block to be processed is divided horizontally (step S1205). As a result of step S1204, the block to be processed is divided into two parts in the vertical direction, as shown in FIG. 602, and as a result of step S1205, the block to be processed is divided into two parts in the horizontal direction, as shown in FIG. 604.

In step S1202, if it is not determined that the block to be processed is to be divided into two, that is, if it is determined to be divided into three, it is determined whether or not to divide the block to be processed in the vertical direction (step S1206). Based on this, the block to be processed is divided vertically (step S1207) or the block to be processed is divided horizontally (step S1208). As a result of step S1207, the block to be processed is divided into three parts in the vertical direction, as shown in FIG. 603, and as a result of step S1208, the block to be processed is divided into three parts in the horizontal direction, as shown in FIG. 605.

After executing any of steps S1204 to S1205, each block obtained by dividing the block to be processed is scanned from left to right and from top to bottom (step S1209). Numbers 0 to 3 from 602 to 605 in FIG. 6 indicate the order of processing. The flowchart of FIG. 8 is called recursively for each divided block.

In the recursive block division described here, the necessity of division may be limited by the number of times of division, the size of the block to be processed, or the like. The information that limits the necessity of division may be realized in a configuration in which no information is transmitted by making a prior agreement between the encoding device and the decoding device, or the encoding device can limit the necessity of division. It may also be realized by a configuration in which the information to be processed is determined and recorded in the encoded bit string to be transmitted to the decoding device.

Here, when a certain block is divided, the block before division is called a parent block, and each block after division is called a child block.

Next, the operation of block dividing section 202 in image decoding device 200 will be explained. The block dividing unit 202 divides a tree block using the same processing procedure as the block dividing unit 101 of the image encoding device 100. However, while the block division unit 101 of the image encoding device 100 determines the optimal block division shape by applying optimization methods such as estimation of the optimal shape through image recognition and distortion rate optimization, the image decoding device The block division unit 202 in 200 is different in that the block division shape is determined by decoding the block division information recorded in the encoded bit string.

FIG. 9 shows the syntax (syntax rules for coded bit strings) regarding block division in the first embodiment. coding_quadtree() represents the syntax for dividing a block into four, and multi_type_tree() represents the syntax for dividing the block into two or three. qt_split is a flag indicating whether or not to divide the block into four. If the block is to be divided into four, qt_split=1, and if not, qt_split=0. When dividing into four (qt_split=1), each block divided into four is recursively processed into four (coding_quadtree(0), coding_quadtree(1), coding_quadtree(2), coding_quadtree(3)). When not dividing into four (qt_split=0), the subsequent division is determined according to multi_type_tree(). mtt_split is a flag indicating whether to further divide. When further dividing (mtt_split=1), refer to mtt_split_vertical, which is a flag indicating whether to divide vertically or horizontally, and mtt_split_binary, which is a flag determining whether to divide into two or three. mtt_split_vertical=1 indicates splitting in the vertical direction, and mtt_split_vertical=0 indicates splitting in the horizontal direction. mtt_split_binary=1 indicates dividing into two, and mtt_split_binary=0 indicates dividing into three. Perform hierarchical block splitting by calling multi_type_tree recursively until mtt_split=0.

<Inter prediction>
The inter prediction method according to the embodiment is implemented in the inter prediction unit 102 of the video encoding device of FIG. 1 and the inter prediction unit 203 of the video decoding device of FIG. 2.

An inter prediction method according to an embodiment will be explained using the drawings. In the inter prediction method, both encoding and decoding processes are performed in units of encoded blocks.

<Description of the inter prediction unit 102 on the encoding side>
FIG. 16 is a diagram showing a detailed configuration of the inter prediction unit 102 of the video encoding device of FIG. 1. The normal predicted motion vector mode derivation unit 301 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, and calculates a difference vector from the detected motion vector. The detected inter prediction mode, reference index, motion vector, and calculated difference vector become inter prediction information of the normal predicted motion vector mode. This inter prediction information is supplied to inter prediction mode determination section 305. The detailed configuration and processing of the normal predicted motion vector mode derivation unit 301 will be described later.

The normal merging mode deriving unit 302 derives a plurality of normal merging candidates, selects the normal merging candidate, and obtains inter prediction information of the normal merging mode. This inter prediction information is supplied to inter prediction mode determination section 305. The detailed configuration and processing of the normal merge mode deriving unit 302 will be described later.

The sub-block predicted motion vector mode derivation unit 303 derives a plurality of sub-block predicted motion vector candidates, selects a sub-block predicted motion vector, and calculates a difference vector from the detected motion vector. The detected inter prediction mode, reference index, motion vector, and calculated difference vector become inter prediction information of the normal predicted motion vector mode. This inter prediction information is supplied to inter prediction mode determination section 305. The detailed configuration and processing of the sub-block predicted motion vector mode deriving unit 303 will be described later.

The subblock merging mode deriving unit 304 derives a plurality of subblock merging candidates, selects a subblock merging candidate, and obtains inter prediction information of the subblock merging mode. This inter prediction information is supplied to inter prediction mode determination section 305. The detailed configuration and processing of the sub-block merge mode deriving unit 304 will be described later.

The inter prediction mode determining unit 305 uses the inter prediction information supplied from the normal predicted motion vector mode deriving unit 301, the normal merge mode deriving unit 302, the sub-block predicted motion vector mode deriving unit 303, and the sub-block merging mode deriving unit 304. , determine the inter prediction mode. Inter prediction information according to the determination result is supplied from the inter prediction mode determination unit 305 to the motion compensation prediction unit 306 .

The motion compensation prediction unit 306 performs inter prediction on the reference image signal stored in the decoded image memory 104 based on the determined inter prediction information. The detailed configuration and processing will be described later.

<Description of the inter prediction unit 203 on the decoding side>
FIG. 22 is a diagram showing a detailed configuration of the inter prediction unit 203 of the video decoding device shown in FIG. 2.

The normal predicted motion vector mode derivation unit 401 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, and calculates a difference vector from the detected motion vector. The detected inter prediction mode, reference index, motion vector, and difference vector become inter prediction information of the normal predicted motion vector mode. This inter prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal predicted motion vector mode deriving unit 401 will be described later.

The normal merging mode deriving unit 402 derives a plurality of normal merging candidates, selects the normal merging candidate, and obtains inter prediction information of the normal merging mode. This inter prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal merge mode deriving unit 402 will be described later.

The sub-block predicted motion vector mode derivation unit 403 derives a plurality of sub-block predicted motion vector candidates, selects a sub-block predicted motion vector, and calculates a difference vector from the detected motion vector. The detected inter prediction mode, reference index, motion vector, and calculated difference vector become inter prediction information of the normal predicted motion vector mode. This inter prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the sub-block predicted motion vector mode deriving unit 403 will be described later.

The subblock merging mode deriving unit 404 derives a plurality of subblock merging candidates, selects a subblock merging candidate, and obtains inter prediction information of the subblock merging mode. This inter prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the sub-block merge mode deriving unit 404 will be described later.

The motion compensation prediction unit 406 performs inter prediction on the reference image signal stored in the decoded image memory 208 based on the determined inter prediction information. The detailed configuration and processing are the same as those on the encoding side.

<Normal predicted motion vector mode derivation unit (normal AMVP)>
The normal predicted motion vector mode derivation unit 301 in FIG. It includes a vector detection section 326, a predicted motion vector candidate selection section 327, and a motion vector subtraction section 328.

The normal predicted motion vector mode deriving unit 401 in FIG. 23 includes a spatial predicted motion vector candidate deriving unit 421, a temporal predicted motion vector candidate deriving unit 422, a historical predicted motion vector candidate deriving unit 423, a predicted motion vector candidate supplementing unit 425, and a predicted motion vector candidate deriving unit 422. It includes a vector candidate selection section 426 and a motion vector addition section 427.

The processing procedures of the normal predicted motion vector mode deriving unit 301 on the encoding side and the normal predicted motion vector mode deriving unit 401 on the decoding side will be explained using the flowcharts of FIGS. 19 and 25, respectively. FIG. 19 is a flowchart showing the normal predicted motion vector mode derivation processing procedure by the normal motion vector mode derivation unit 301 on the encoding side, and FIG. 25 is the normal predicted motion vector mode derivation process by the normal motion vector mode derivation unit 401 on the decoding side. It is a flowchart showing a procedure.

<Normal predicted motion vector mode derivation unit (normal AMVP): Description of encoding side>
The normal predicted motion vector mode derivation processing procedure on the encoding side will be described with reference to FIG. In the description of the processing procedure in FIG. 19, the term "motion vector" in the specification and the term "normal motion vector" in FIG. 19 are assumed to correspond.
First, the normal motion vector detection unit 326 detects a normal motion vector for each inter prediction mode and reference index (step S100 in FIG. 19).

Subsequently, a spatial predicted motion vector candidate derivation unit 321, a temporal predicted motion vector candidate derivation unit 322, a historical predicted motion vector candidate derivation unit 323, a predicted motion vector candidate supplementation unit 325, a predicted motion vector candidate selection unit 327, and a motion vector subtraction unit At 328, a differential motion vector of the motion vectors used in inter prediction in the normal predicted motion vector mode is calculated for each of L0 and L1 (steps S101 to S106 in FIG. 19). Specifically, if the prediction mode PredMode of the block to be processed is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), calculate the L0 predicted motion vector candidate list mvpListL0 and select the predicted motion vector mvpL0. Then, a differential motion vector mvdL0 of the motion vector mvL0 of L0 is calculated. If the inter prediction mode of the block to be processed is L1 prediction (Pred_L1), calculate the L1 motion vector predictor candidate list mvpListL1, select the motion vector predictor mvpL1, and calculate the differential motion vector mvdL1 of the L1 motion vector mvL1. . When the inter prediction mode of the block to be processed is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, L0 predicted motion vector candidate list mvpListL0 is calculated, L0 predicted motion vector mvpL0 is selected, and L0 prediction is performed. Calculate the differential motion vector mvdL0 of the motion vector mvL0 of L1, calculate the predicted motion vector candidate list mvpListL1 of L1, calculate the predicted motion vector mvpL1 of L1, and calculate the differential motion vector mvdL1 of the motion vector mvL1 of L1, respectively. do.

Although differential motion vector calculation processing is performed for each of L0 and L1, the processing is common to both L0 and L1. Therefore, in the following description, L0 and L1 will be expressed as a common LX. In the process of calculating the differential motion vector of L0, X is 0, and in the process of calculating the differential motion vector of L1, X is 1. Furthermore, when referring to information in another list instead of LX during the process of calculating the differential motion vector of LX, the other list is expressed as LY.

When using the LX motion vector mvLX (step S102 in FIG. 19: YES), candidates for the LX motion vector predictor are calculated and an LX motion vector predictor candidate list mvpListLX is constructed (step S103 in FIG. 19). The spatial predicted motion vector candidate derivation unit 321, the temporal predicted motion vector candidate derivation unit 322, the historical predicted motion vector candidate derivation unit 323, and the predicted motion vector candidate supplementation unit 325 in the normal predicted motion vector mode derivation unit 301 generate a plurality of predicted motions. Derive vector candidates and construct a predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S103 in FIG. 19 will be described later using the flowchart in FIG. 20.

Subsequently, the motion vector predictor candidate selection unit 327 selects the motion vector predictor mvpLX of LX from the motion vector predictor candidate list mvpListLX of LX (step S104 in FIG. 19). Each differential motion vector is calculated as the difference between the motion vector mvLX and each motion vector predictor candidate mvpListLX[i] stored in the motion vector predictor candidate list mvpListLX[i]. The amount of code when these differential motion vectors are encoded is calculated for each element of the motion vector predictor candidate list mvpListLX. Then, among the elements registered in the motion vector predictor candidate list mvpListLX, the motion vector predictor candidate mvpListLX[i] with the minimum code amount for each motion vector predictor candidate is selected as the motion vector predictor mvpLX, and Get index i. If there are multiple motion vector predictor candidates with the smallest generated code amount in the motion vector predictor candidate list mvpListLX, the motion vector predictor whose index i in the motion vector predictor candidate list mvpListLX is represented by a smaller number is used. Select candidate mvpListLX[i] as the optimal predicted motion vector mvpLX, and obtain its index i.

Next, the motion vector subtraction unit 328 subtracts the selected LX predicted motion vector mvpLX from the LX motion vector mvLX,
mvdLX = mvLX - mvpLX
Then, a differential motion vector mvdLX of LX is calculated (step S105 in FIG. 19).

<Normal predicted motion vector mode derivation unit (normal AMVP): Description of decoding side>
Next, the normal predicted motion vector mode processing procedure on the decoding side will be described with reference to FIG. On the decoding side, a spatial predicted motion vector candidate derivation unit 421, a temporal predicted motion vector candidate derivation unit 422, a historical predicted motion vector candidate derivation unit 423, and a predicted motion vector candidate supplementation unit 425 use the predicted motion vector candidate for inter prediction in the normal predicted motion vector mode. Motion vectors are calculated for each of L0 and L1 (steps S201 to S206 in FIG. 25). Specifically, when the prediction mode PredMode of the target block is inter prediction (MODE_INTER) and the inter prediction mode of the target block is L0 prediction (Pred_L0), the predicted motion vector candidate list mvpListL0 of L0 is calculated and the predicted motion Select vector mvpL0 and calculate motion vector mvL0 of L0. When the inter prediction mode of the block to be processed is L1 prediction (Pred_L1), an L1 motion vector predictor candidate list mvpListL1 is calculated, the predicted motion vector mvpL1 is selected, and the L1 motion vector mvL1 is calculated. When the inter prediction mode of the block to be processed is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, L0 predicted motion vector candidate list mvpListL0 is calculated, L0 predicted motion vector mvpL0 is selected, and L0 prediction is performed. The motion vector mvL0 of L1 is calculated, the predicted motion vector candidate list mvpListL1 of L1 is calculated, the predicted motion vector mvpL1 of L1 is calculated, and the motion vector mvL1 of L1 is calculated, respectively.

Similar to the encoding side, motion vector calculation processing is performed for each of L0 and L1 on the decoding side, but the processing is common for both L0 and L1. Therefore, in the following description, L0 and L1 will be expressed as a common LX. LX represents an inter prediction mode used for inter prediction of the encoded block to be processed. In the process of calculating the motion vector of L0, X is 0, and in the process of calculating the motion vector of L1, X is 1. Further, during the process of calculating the motion vector of LX, when referring to information in another reference list instead of the same reference list as the LX to be calculated, the other reference list is expressed as LY.

When using the LX motion vector mvLX (step S202 in FIG. 25: YES), candidates for the LX motion vector predictor are calculated and an LX motion vector predictor candidate list mvpListLX is constructed (step S203 in FIG. 25). A spatial predicted motion vector candidate derivation unit 421, a temporal predicted motion vector candidate derivation unit 422, a historical predicted motion vector candidate derivation unit 423, and a predicted motion vector candidate supplementation unit 425 in the normal predicted motion vector mode derivation unit 401 generate a plurality of predicted motions. Calculate vector candidates and construct a predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S203 in FIG. 25 will be described later using the flowchart in FIG.

Next, the motion vector predictor candidate selection unit 426 selects the motion vector predictor candidate mvpListLX[mvpIdxLX] corresponding to the motion vector predictor index mvpIdxLX decoded and supplied by the bit string decoding unit 201 from the motion vector predictor candidate list mvpListLX. The predicted motion vector mvpLX is extracted (step S204 in FIG. 25).

Next, the motion vector addition unit 427 adds the LX differential motion vector mvdLX decoded and supplied by the bit string decoding unit 201 and the LX predicted motion vector mvpLX,
mvLX = mvpLX + mvdLX
The motion vector mvLX of LX is calculated as (step S205 in FIG. 25).

<Normal predicted motion vector mode derivation unit (normal AMVP): Motion vector prediction method>
FIG. 20 shows a normal predicted motion vector having a function common to the normal predicted motion vector mode derivation unit 301 of the video encoding device and the normal predicted motion vector mode derivation unit 401 of the video decoding device according to the embodiment of the present invention. 3 is a flowchart illustrating the processing procedure of mode derivation processing.

The normal predicted motion vector mode deriving unit 301 and the normal predicted motion vector mode deriving unit 401 are provided with a predicted motion vector candidate list mvpListLX. The motion vector predictor candidate list mvpListLX has a list structure, and is provided with a motion vector predictor index indicating the location within the motion vector predictor candidate list and a storage area for storing the motion vector predictor candidate corresponding to the index as an element. The motion vector predictor index number starts from 0, and the motion vector predictor candidates are stored in the storage area of the motion vector predictor candidate list mvpListLX. In this embodiment, it is assumed that the motion vector predictor candidate list mvpListLX can register at least two motion vector predictor candidates (inter prediction information). Further, a variable numCurrMvpCand indicating the number of motion vector predictor candidates registered in the motion vector predictor candidate list mvpListLX is set to 0.

The spatial predictive motion vector candidate deriving units 321 and 421 derive predictive motion vector candidates from blocks adjacent to the left. In this process, a flag availableFlagLXA indicating whether a motion vector predictor candidate for the block adjacent to the left (A0 or A1) is available, a motion vector mvLXA, and a reference index refIdxA are derived, and mvLXA is a motion vector predictor candidate list mvpListLX (Step S301 in FIG. 20). Note that when L0, X is 0, and when L1, X is 1 (the same applies hereinafter). Subsequently, the spatial predicted motion vector candidate deriving units 321 and 421 derive a predicted motion vector candidate from the upper adjacent block (B0, B1, or B2). In this process, a flag availableFlagLXB indicating whether the motion vector predictor candidate of the upper adjacent block is available, a motion vector mvLXB, and a reference index refIdxB are derived, and if mvLXA and mvLXB are not equal, mvLXB is used as the motion vector predictor It is added to the candidate list mvpListLX (step S302 in FIG. 20). The processes in steps S301 and S302 in FIG. 20 are common except that the positions and numbers of adjacent blocks to be referenced are different, and include a flag availableFlagLXN indicating whether a motion vector predictor candidate for the encoded block is available, and a motion vector mvLXN. , a reference index refIdxN (N is A or B, hereinafter the same) is derived.

Subsequently, the temporal motion vector predictor candidate deriving units 322 and 422 derive motion vector predictor candidates from encoded blocks in a picture whose time is different from the current picture to be processed. In this process, a flag availableFlagLXCol indicating whether a motion vector predictor candidate for a coded block in a picture at a different time is available, a motion vector mvLXCol, a reference index refIdxCol, and a reference list listCol are derived, and mvLXCol is used as a motion vector predictor candidate. It is added to the list mvpListLX (step S303 in FIG. 20). The derivation processing procedure in step S303 will be explained in detail later.

Note that the processing of the temporal motion vector predictor candidate derivation units 322 and 422 can be omitted in sequence (SPS), picture (PPS), or slice units.

Subsequently, the historical predicted motion vector candidate derivation units 323 and 423 add the historical predicted motion vector candidates registered in the historical predicted motion vector candidate list HmvpCandList to the predicted motion vector candidate list mvpListLX. (Step S304 in FIG. 20). The registration processing procedure of step S304 will be explained in detail later using the flowchart of FIG.

Subsequently, the motion vector predictor candidate replenishment units 325 and 425 add motion vectors of predetermined values, such as (0, 0), until the motion vector predictor candidate list mvpListLX is filled (S305 in FIG. 20).

<Normal merge mode derivation part (normal merge)>
The normal merge mode deriving unit 302 in FIG. 18 includes a spatial merge candidate deriving unit 341, a temporal merge candidate deriving unit 342, an average merge candidate deriving unit 344, a history merge candidate deriving unit 345, a merge candidate supplementing unit 346, and a merge candidate selecting unit 347. including.

The normal merge mode deriving unit 402 in FIG. 24 includes a spatial merge candidate deriving unit 441, a temporal merge candidate deriving unit 442, an average merge candidate deriving unit 444, a history merge candidate deriving unit 445, a merge candidate supplementing unit 446, and a merge candidate selecting unit 447. including.

FIG. 21 shows the procedure of a normal merge mode deriving process that has a common function in the normal merge mode deriving unit 302 of the video encoding device and the normal merge mode deriving unit 402 of the video decoding device according to the embodiment of the present invention. It is a flowchart explaining.

The various processes will be explained step by step below. Note that in the following description, unless otherwise specified, the case where the slice type slice_type is a B slice will be described, but it can also be applied to a case where the slice type is a P slice. However, if the slice type slice_type is P slice, there is only L0 prediction (Pred_L0) as an inter prediction mode, and there is no L1 prediction (Pred_L1) or bi-prediction (Pred_BI), so the processing related to L1 can be omitted.

The normal merge mode deriving unit 302 and the normal merge mode deriving unit 402 are provided with a merge candidate list mergeCandList. The merge candidate list mergeCandList has a list structure, and is provided with a merge index indicating the location within the merge candidate list and a storage area for storing the merge candidate corresponding to the index as an element. The merge index number starts from 0, and the merge candidates are stored in the storage area of the merge candidate list mergeCandList. In the subsequent processing, the merge candidate with merge index i registered in the merge candidate list mergeCandList will be represented by mergeCandList[i]. In this embodiment, it is assumed that the merge candidate list mergeCandList can register at least six merge candidates (inter prediction information). Further, a variable numCurrMergeCand indicating the number of merge candidates registered in the merge candidate list mergeCandList is set to 0.

The spatial merging candidate deriving unit 341 and the spatial merging candidate deriving unit 441 perform processing from the encoded information stored in the encoded information storage memory 111 of the video encoding device or the encoded information storage memory 205 of the video decoder. Spatial merging candidates A and B are derived from blocks adjacent to the left side and above the target block, and the derived spatial merging candidates are registered in the merging candidate list mergeCandList (step S401 in FIG. 21). Here, N indicating either the spatial merging candidates A, B or the temporal merging candidate Col is defined. A flag availableFlagN that indicates whether the inter prediction information of block N can be used as spatial merging candidate N, L0 reference index refIdxL0N and L1 reference index refIdxL1N of spatial merging candidate N, L0 that indicates whether L0 prediction is performed or not. A prediction flag predFlagL0N, an L1 prediction flag predFlagL1N indicating whether or not L1 prediction is performed, an L0 motion vector mvL0N, and an L1 motion vector mvL1N are derived. However, in this embodiment, merging candidates are derived without referring to other coded blocks included in the block including the coded block to be processed. It does not derive spatial merge candidates.

Next, the temporal merging candidate deriving unit 342 and the temporal merging candidate deriving unit 442 derive temporal merging candidates from pictures at different times, and register the derived temporal merging candidates in the merge candidate list mergeCandList (see FIG. 21). Step S402). A flag availableFlagCol indicating whether a temporal merging candidate is available, an L0 prediction flag predFlagL0Col indicating whether L0 prediction of the temporal merging candidate will be performed, an L1 prediction flag predFlagL1Col indicating whether L1 prediction will be performed, and L0 The motion vector mvL0Col of L1 and the motion vector mvL1Col of L1 are derived. The detailed processing procedure of step S402 will be explained in detail later with reference to FIG. 56.

Note that the processing of the temporal merging candidate deriving section 342 and the temporal merging candidate deriving section 442 can be omitted in units of sequence (SPS), picture (PPS), or slice.

Subsequently, the history merge candidate deriving unit 345 and the history merge candidate deriving unit 445 add the history predicted motion vector candidates registered in the history predicted motion vector candidate list HmvpCandList to the merge candidate list mergeCandList (step S403 in FIG. 21). . The detailed processing procedure of step S403 will be explained in detail later using the flowchart of FIG. 62.

Subsequently, the average merge candidate deriving unit 344 and the average merge candidate deriving unit 444 derive average merge candidates from the merge candidate list mergeCandList, and register the derived average merge candidates in the merge candidate list mergeCandList (steps in FIG. 21). S404). The detailed processing procedure of step S404 will be explained in detail later using the flowchart of FIG.

Next, in the merge candidate replenishment unit 346 and the merge candidate replenishment unit 446, if the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, the merge candidate replenishment unit 346 and the merge candidate replenishment unit 446 The number of merge candidates numCurrMergeCand is set to the maximum number of merge candidates MaxNumMergeCand as an upper limit, and additional merge candidates are derived and registered in the merge candidate list mergeCandList (step S405 in FIG. 21). With the maximum number of merging candidates MaxNumMergeCand as an upper limit, in P slices, merging candidates whose prediction mode is L0 prediction (Pred_L0) and whose motion vector has a value of (0,0) with different reference indexes are added. In the B slice, a merging candidate whose prediction mode is bi-prediction (Pred_BI) and whose motion vector has a value of (0, 0) with a different reference index is added.

Subsequently, the merge candidate selection unit 347 and the merge candidate selection unit 447 select a merge candidate from the merge candidates registered in the merge candidate list mergeCandList. The merging candidate selection unit 347 on the encoding side selects a merging candidate by calculating the code amount and distortion amount, and sends the merging index indicating the selected merging candidate and the inter prediction information of the merging candidate to the motion compensation prediction unit 306. supply On the other hand, the merging candidate selection unit 447 on the decoding side selects a merging candidate based on the decoded merging index, and supplies the selected merging candidate to the motion compensation prediction unit 406.

When the size (product of width and height) of a certain encoding block is less than 32, the normal merging mode deriving unit 302 and the normal merging mode deriving unit 402 derive merging candidates in the parent block of the encoding block. Then, all child blocks use the merging candidates derived in the parent block. However, this is limited to cases where the size of the parent block is 32 or more and fits within the screen.

<Derivation of sub-block predicted motion vector mode>
Derivation of sub-block predicted motion vector mode will be explained.

FIG. 26 is a block diagram of the sub-block predicted motion vector mode deriving unit 303 in the encoding device of this embodiment.

First, the affine inheritance predicted motion vector candidate derivation unit 361 derives affine inheritance predicted motion vector candidates. Details of deriving affine inheritance predicted motion vector candidates will be described later.

Subsequently, the affine constructed predicted motion vector candidate derivation unit 362 derives affine constructed predicted motion vector candidates. The details of deriving affine construction predicted motion vector candidates will be described later.

Subsequently, the affine identically predicted motion vector candidate deriving unit 363 derives affine identically predicted motion vector candidates. Details of deriving affine identically predicted motion vector candidates will be described later.

The sub-block motion vector detection unit 366 detects a sub-block motion vector suitable for the sub-block predicted motion vector mode, and supplies the detected vector to the sub-block predicted motion vector candidate selection unit 367 and the difference calculation unit 368.

The sub-block predicted motion vector candidate selection unit 367 selects the sub-block predicted motion vector candidates derived by the affine inheritance predicted motion vector candidate derivation unit 361, the affine construction predicted motion vector candidate derivation unit 362, and the affine identical predicted motion vector candidate derivation unit 363. From among them, a sub-block predicted motion vector candidate is selected based on the motion vector supplied from the sub-block motion vector detection unit 366, and information regarding the selected sub-block predicted motion vector candidate is transmitted to the inter prediction mode determination unit 305, It is supplied to the difference calculation section 368.

The difference calculation unit 368 subtracts the sub-block predicted motion vector selected by the sub-block predicted motion vector candidate selection unit 367 from the motion vector supplied from the sub-block motion vector detection unit 366, and calculates the differential predicted motion vector using an interface. It is supplied to the prediction mode determination unit 305.

FIG. 27 is a block diagram of sub-block predicted motion vector mode deriving section 403 in the decoding device of this embodiment.

First, the affine inheritance predicted motion vector candidate derivation unit 461 derives an affine inheritance predicted motion vector candidate. The processing of the affine inheritance predicted motion vector candidate derivation unit 461 is the same as the processing of the affine inheritance predicted motion vector candidate derivation unit 361 in the encoding device of this embodiment.

Subsequently, the affine constructed predicted motion vector candidate derivation unit 462 derives affine constructed predicted motion vector candidates. The processing of the affine construction predicted motion vector candidate derivation unit 462 is the same as the processing of the affine construction prediction motion vector candidate derivation unit 362 in the encoding device of this embodiment.

Subsequently, the affine identically predicted motion vector candidate deriving unit 463 derives affine identically predicted motion vector candidates. The processing of the affine identically predicted motion vector candidate deriving unit 463 is the same as the processing of the affine identically predicted motion vector candidate deriving unit 363 in the encoding device of this embodiment.

The sub-block predicted motion vector candidate selection unit 466 selects the sub-block predicted motion vector candidates derived by the affine inheritance predicted motion vector candidate derivation unit 461, the affine construction predicted motion vector candidate derivation unit 462, and the affine identical predicted motion vector candidate derivation unit 463. A sub-block predicted motion vector candidate is selected from among them based on the predicted motion vector index transmitted from the encoding device and decoded, and the motion compensation prediction unit 406 adds information regarding the selected sub-block predicted motion vector candidate. The signal is supplied to the calculation unit 467.

The addition calculation unit 467 performs motion compensation prediction on the motion vector generated by adding the differential motion vector transmitted from the encoding device and decoded to the sub-block predicted motion vector selected by the sub-block predicted motion vector candidate selection unit 466. 406.

<Derivation of affine inheritance predicted motion vector candidates>
The affine inheritance predicted motion vector candidate deriving unit 361 will be explained. The affine inheritance predicted motion vector candidate derivation unit 461 is also similar to the affine inheritance predicted motion vector candidate derivation unit 361.

The affine inheritance predicted motion vector candidate inherits the motion vector information of the control point.

FIG. 30 is a diagram illustrating derivation of affine inheritance predicted motion vector candidates.

Affine inheritance predicted motion vector candidates are obtained by searching motion vectors of control points of spatially adjacent encoded and decoded blocks.

Specifically, a maximum of one affine mode is searched for each of the blocks (A0, A1) adjacent to the left side of the block to be processed and the blocks (B0, B1, B2) adjacent to the upper side of the block to be processed. , is an affine inheritance predicted motion vector.

FIG. 34 is a flowchart of deriving affine inheritance predicted motion vector candidates.

First, blocks (A0, A1) adjacent to the left side of the block to be processed are set as a left group (step S3101), and it is determined whether the block including A0 is a block using affine transformation motion compensation (affine mode). (Step S3102). If A0 is in the affine mode (step S3102: YES), the affine mode used by A0 is acquired (step S3103), and the process moves to the upper adjacent block. If A0 is not in affine mode (step S3102: NO), the target for deriving affine inheritance predicted motion vector candidates is set to A0->A1, and an attempt is made to obtain affine mode from the block including A1.

Next, blocks (B0, B1, B2) adjacent to the upper side of the block to be processed are set as an upper group (step S3104), and it is determined whether the block including B0 is in affine mode (step S3105). If B0 is in the affine mode (step S3105: YES), the affine mode used by B0 is acquired (step S3106), and the process ends. If B0 is not in affine mode (step S3105: NO), the target for deriving affine inheritance predicted motion vector candidates is set to B0->B1, and an attempt is made to obtain affine mode from the block including B1. Furthermore, if B1 is not in affine mode (step S3105: NO), the target for deriving affine inheritance predicted motion vector candidates is set as B1->B2, and an attempt is made to obtain affine mode from the block including B2.

In this way, the groups are divided into the left block and the upper block, and for the left block, the affine mode is searched in order from the lower left block to the upper left block, and for the left block, the affine mode is searched in order from the upper right block to the upper left block. By doing so, it is possible to obtain two affine modes that are as different as possible, and it is possible to derive an affine predicted motion vector candidate in which one of the affine predicted motion vectors has a smaller differential motion vector.

<Derivation of affine construction predicted motion vector candidates>
The affine construction predicted motion vector candidate deriving unit 362 will be explained. The affine constructed predicted motion vector candidate deriving unit 462 is also similar to the affine constructed predicted motion vector candidate deriving unit 362.

The affine constructed predicted motion vector candidate constructs motion vector information of a control point from motion information of spatially adjacent blocks.

FIG. 31 is a diagram illustrating derivation of affine construction predicted motion vector candidates.

An affine construction predicted motion vector candidate is obtained by combining motion vectors of spatially adjacent encoded and decoded blocks to construct a new affine mode.

Specifically, the motion vector of the upper left control point CP0 is derived from the blocks (B2, B3, A2) adjacent to the upper left side of the block to be processed, and the motion vector of the upper left control point CP0 is derived from the blocks (B1, B0) adjacent to the upper right side of the block to be processed. ), the motion vector of the upper right control point CP1 is derived, and the motion vector of the lower left control point CP2 is derived from the block (A1, A0) adjacent to the lower left side of the block to be processed.

FIG. 35 is a flowchart of deriving affine construction predicted motion vector candidates.

First, the upper left control point CP0, the upper right control point CP1, and the lower left control point CP2 are derived (step S3201). The upper left control point CP0 is calculated by searching for a reference block having the same reference image as the block to be processed in the priority order of B2, B3, and A2 reference blocks. The upper right control point CP1 is calculated by searching for a reference block having the same reference image as the block to be processed in priority order of B1 and B0 reference blocks. The lower left control point CP2 is calculated by searching for a reference block having the same reference image as the block to be processed in priority order of A1 and A0 reference blocks.

When selecting the three control point mode as the affine construction predicted motion vector (step S3202: YES), it is determined whether all three control points (CP0, CP1, CP2) have been derived (step S3203). If all three control points (CP0, CP1, CP2) have been derived (step S3203: YES), an affine model using the three control points (CP0, CP1, CP2) is set as an affine constructed predicted motion vector (step S3204). If the three control point mode is not selected but the two control point mode is selected (step S3202: NO), it is determined whether all two control points (CP0, CP1) have been derived (step S3205). If all the two control points (CP0, CP1) have been derived (step S3205: YES), the affine model using the two control points (CP0, CP1) is set as the affine constructed predicted motion vector (step S3206).

<Derivation of affine identical predicted motion vector candidates>
The affine identically predicted motion vector candidate deriving unit 363 will be explained. The affine identically predicted motion vector candidate deriving unit 463 is also similar to the affine identically predicted motion vector candidate deriving unit 363 .

Affine identical predicted motion vector candidates are obtained by deriving the same motion vector at each control point.

Specifically, similar to the affine construction predicted motion vector candidate deriving units 362 and 462, this is obtained by deriving each control point information and setting all control points to be the same at any one of CP0 to CP2. It can also be obtained by setting temporal motion vectors derived in the same way as in the normal predicted motion vector mode to all control points.

<Sub-block merge mode derivation>
Derivation of sub-block merge mode will be explained.

FIG. 28 is a block diagram of subblock merge mode deriving section 304 in the encoding device of this embodiment. The subblock merging mode deriving unit 304 includes a subblock merging candidate list subblockMergeCandList. This has a list structure similar to the merge candidate list mergeCandList in the normal merge mode derivation unit 302, and stores the merge index indicating the location inside the sub-block merge candidate list and the sub-block merge candidate corresponding to the index as elements. A storage area is provided. In this embodiment, it is assumed that the subblock merging candidate list subblockMergeCandList can register at least five merging candidates (inter prediction information). However, each merging candidate further has motion vector information for each subblock or motion vector information for a control point.

First, the sub-block time merging candidate deriving unit 381 derives sub-block time merging candidates. Details of sub-block time merging candidate derivation will be described later.

Subsequently, the affine inheritance merge candidate deriving unit 382 derives affine inheritance merge candidates. Details of deriving affine inheritance merge candidates will be described later.

Subsequently, the affine construction merge candidate derivation unit 383 derives affine construction merge candidates. Details of deriving affine construction merge candidates will be described later.

Subsequently, the affine fixed merge candidate deriving unit 385 derives affine fixed merge candidates. Details of deriving affine fixed merge candidates will be described later.

The sub-block merging candidate selection unit 386 selects the sub-block merging candidates derived by the sub-block temporal merging candidate deriving unit 381, the affine inheritance merging candidate deriving unit 382, the affine construction merging candidate deriving unit 383, and the affine fixed merging candidate deriving unit 385. A sub-block merging candidate is selected from among them, and information regarding the selected sub-block merging candidate is supplied to the inter prediction mode determining unit 305.

FIG. 29 is a block diagram of sub-block merge mode deriving section 404 in the decoding device of this embodiment. The subblock merging mode deriving unit 404 includes a subblock merging candidate list subblockMergeCandList. This is the same as the subblock merge mode deriving unit 304.

First, the sub-block time merging candidate deriving unit 481 derives sub-block time merging candidates. The processing of the sub-block time merging candidate deriving unit 481 is the same as the processing of the sub-block time merging candidate deriving unit 381.

Subsequently, the affine inheritance merge candidate deriving unit 482 derives affine inheritance merge candidates. The processing of the affine inheritance merge candidate deriving unit 482 is the same as the processing of the affine inheritance merge candidate deriving unit 382.

Subsequently, the affine construction merge candidate deriving unit 483 derives affine construction merge candidates. The processing of the affine construction merge candidate derivation unit 483 is the same as the processing of the affine construction merge candidate derivation unit 383.

Subsequently, the affine fixed merge candidate deriving unit 485 derives affine fixed merge candidates. The processing of the affine fixed merge candidate deriving unit 485 is the same as the processing of the affine fixed merge candidate deriving unit 485.

The sub-block merging candidate selection unit 486 selects the sub-block merging candidates derived by the sub-block temporal merging candidate deriving unit 481, the affine inheritance merging candidate deriving unit 482, the affine construction merging candidate deriving unit 483, and the affine fixed merging candidate deriving unit 485. From among them, a sub-block merging candidate is selected based on the index transmitted from the encoding device and decoded, and information regarding the selected sub-block merging candidate is supplied to the motion compensation prediction unit 406.

Sub-block merging mode deriving unit 304 and sub-block merging mode deriving unit 404 determine that when the size (product of width and height) of a certain coding block is less than 32, sub-block merging candidates are detected in the parent block of the coding block. derived. Then, all child blocks use the subblock merging candidates derived in the parent block. However, this is limited to cases where the size of the parent block is 32 or more and fits within the screen.

<Derivation of sub-block time merging candidates>
The operation of the sub-block time merging candidate deriving unit 381 will be described later.

<Affine inheritance merge candidate derivation>
The affine inheritance merge candidate deriving unit 382 will be explained. The affine inheritance merge candidate deriving unit 482 is also similar to the affine inheritance merge candidate deriving unit 382.

An affine inheritance merge candidate inherits an affine model of a control point from an affine model of a spatially adjacent block.

FIG. 32 is a diagram illustrating derivation of affine inheritance merge candidates. Similar to the derivation of affine inheritance predicted motion vectors, affine merging inheritance merge mode candidates can be derived by searching for motion vectors of control points of spatially adjacent encoded and decoded blocks.

Specifically, a maximum of one affine mode is searched for each of the blocks (A0, A1) adjacent to the left side of the block to be processed and the blocks (B0, B1, B2) adjacent to the upper side of the block to be processed. , used for affine merge mode.

FIG. 36 is a flowchart of deriving affine inheritance merge candidates.

First, blocks (A0, A1) adjacent to the left side of the block to be processed are set as a left group (step S3301), and it is determined whether the block including A0 is in affine mode (step S3302). If A0 is in affine mode (step S3102: YES), the affine model used by A0 is acquired (step S3303), and the process moves to the upper adjacent block. If A0 is not in affine mode (step S3302: NO), the target for deriving affine inheritance merge candidates is set to A0->A1, and an attempt is made to obtain affine mode from the block containing A1.

Next, blocks (B0, B1, B2) adjacent to the upper side of the block to be processed are set as an upper group (step S3304), and it is determined whether the block including B0 is in affine mode (step S3305). If B0 is in affine mode (step S3305: YES), the affine model used by B0 is acquired (step S3306), and the process ends. If B0 is not in affine mode (step S3305: NO), the target for deriving affine inheritance merge candidates is set to B0->B1, and an attempt is made to obtain affine mode from the block including B1. Further, if B1 is not in affine mode (step S3305: NO), the target for deriving affine inheritance merge candidates is set as B1->B2, and an attempt is made to obtain affine mode from the block including B2.

<Derivation of affine construction merge candidates>
The affine construction merge candidate deriving unit 383 will be explained. The affine construction merge candidate derivation unit 483 is also similar to the affine construction merge candidate derivation unit 383.

FIG. 33 is a diagram illustrating derivation of affine construction merge candidates. The affine construction merge candidate constructs an affine model of a control point from motion information of spatially adjacent blocks and temporally encoded blocks.

Specifically, the motion vector of the upper left control point CP0 is derived from the blocks (B2, B3, A2) adjacent to the upper left side of the block to be processed, and the motion vector of the upper left control point CP0 is derived from the blocks (B1, B0) adjacent to the upper right side of the block to be processed. ), derive the motion vector of the upper right control point CP1 from the block (A1, A0) adjacent to the lower left side of the block to be processed, and derive the motion vector of the lower left control point CP2 from the block (A1, A0) adjacent to the lower left side of the block to be processed. The motion vector of the lower right control point CP3 is derived from the encoded block (T0) adjacent to .

FIG. 37 is a flowchart of deriving affine construction merge candidates.

First, the upper left control point CP0, the upper right control point CP1, the lower left control point CP2, and the lower right control point CP3 are derived (step S3401). The upper left control point CP0 is calculated by searching for blocks having motion information in the priority order of B2, B3, and A2 blocks. The upper right control point CP1 is calculated by searching for blocks having motion information in the priority order of B1 and B0 blocks. The lower left control point CP2 is calculated by searching for blocks having motion information in priority order of A1 and A0 blocks. The lower right control point CP3 is calculated by searching the motion information of the time block.

Next, it is determined whether an affine model with three control points can be constructed using the derived CP0, CP1, and CP2 (step S3402), and if it is possible to construct an affine model with three control points (step S3402: YES), CP0, CP1 , CP2 is set as an affine merge candidate (step S3403).

Next, it is determined whether an affine model with three control points can be constructed using the derived CP0, CP1, and CP3 (step S3404), and if it is possible to construct an affine model (step S3404: YES), CP0, CP1 , CP3 is set as an affine merge candidate (step S3405).

Next, it is determined whether an affine model with three control points can be constructed using the derived CP0, CP2, and CP3 (step S3406), and if it is possible to construct an affine model with three control points (step S3406: YES), CP0, CP2 , CP3 is set as an affine merge candidate (step S3407).

Next, it is determined whether an affine model with three control points can be constructed using the derived CP1, CP2, and CP3 (step S3408), and if it is possible to construct an affine model with three control points (step S3408: YES), CP1, CP2 , CP3 is set as an affine merge candidate (step S3409).

Next, it is determined whether or not it is possible to construct an affine model with two control points using the derived CP0 and CP1 (step S3410), and if it is possible to construct an affine model with two control points (step S3410: YES), the two control points are This control point affine model is set as an affine merge candidate (step S3411).

Next, it is determined whether it is possible to construct an affine model with two control points using the derived CP0 and CP2 (step S3412), and if it is possible to construct an affine model with two control points (step S3412: YES), the two control points are This control point affine model is set as an affine merge candidate (step S3413).

Here, whether or not it is possible to construct an affine model is determined at least on the condition that the reference images of all control points are the same (affine transformation is possible). In addition, affine models other than the 3-control point affine model with CP0, CP1, and CP2 and the 2-control point affine model with CP0, CP1 are the 3-control point affine model with CP0, CP1, and CP2. A two-control affine model is converted into a two-control point affine model using CP0 and CP1.

<Derivation of affine fixed merge candidates>
The affine fixed merge candidate deriving unit 385 will be explained. The affine fixed merge candidate deriving unit 485 is also similar to the affine fixed merge candidate deriving unit 385.

An affine fixed merge candidate fixes the motion information of a control point using fixed motion information.

Specifically, the motion vector of each control point is fixed to (0, 0).

<Derivation of temporally predicted motion vector>
Prior to explaining the temporally predicted motion vector, the temporal context of pictures will be explained with reference to FIG. 49. FIG. 49A shows the relationship between a coded block to be processed and a coded picture that is temporally different from the picture to be processed. A specific encoded picture referred to in encoding the processing target picture is defined as ColPic. ColPic is specified by syntax.

Moreover, FIG. 49(b) shows coded blocks existing at the same position as the processing target coded block and in the vicinity thereof in ColPic. However, the encoded blocks T0 and T1 shown in FIG. 49(b) are schematic, and the actual positions and sizes are not limited to these. Now, let us say that the position of the encoded block to be processed is (xCb, yCb), the width is cbWidth, and the height is cbHeight. and,
xColBr = xCb + cbWidth
yColBr = yCb + cbHeight
Calculate. The coded block on ColPic that includes the position ((xColBr >> 3) << 3, (yColBr >> 3) << 3) is T0. Also,
xColCtr = xCb + (cbWidth >> 1)
yColCtr = yCb + (cbHeight >> 1)
Calculate. The coded block on ColPic that includes the position ((xColCtr >> 3) << 3, (yColCtr >> 3) << 3) is T1.

The above description of the temporal context of pictures is for encoding, but the same applies for decoding. In other words, decoding will be explained in the same manner by replacing encoding in the above description with decoding.

The operation of the temporally predicted motion vector candidate deriving unit 322 in the normal predicted motion vector mode deriving unit 301 in FIG. 17 will be described with reference to FIG. 50.

First, ColPic is derived (step S4201). The derivation of ColPic will be explained with reference to FIG. 51.

If the slice type slice_type is B slice and the flag collocated_from_l0_flag is 0 (step S4211: YES, step S4212: YES), the picture ColPic at a different time becomes the picture RefPicList1[0] with the reference index of 0 in the reference list L1 ( Step S4213). Otherwise, if the slice type slice_type is a B slice and the aforementioned flag collocated_from_l0_flag is 1 (step S4211: YES, step S4212: NO), or if the slice type slice_type is a P slice (step S4211: NO, step S4214: YES), the picture ColPic at a different time becomes the picture RefPicList0[0] whose reference index in the reference list L0 is 0 (step S4215). If slice_type is not a P slice (step S4214: NO), the process ends.

Refer to FIG. 50 again. After deriving ColPic, a coded block colCb is derived and coded information is obtained (step S4202). This process will be explained with reference to FIG. 52.

First, in the picture ColPic of a different time, a coded block containing the same lower right position as the coded block to be coded is set as a coded block colCb of a different time (step S4221). An example of this encoded block is shown as encoded block T0 in FIG. 49.

Next, the encoding information of the encoded block colCb at a different time is acquired (step S4222). If the PredMode of the coded block colCb at a different time is not available or the prediction mode PredMode of the coded block colCb at a different time is intra prediction (MODE_INTRA) (step S4223: NO, step S4224: YES), the picture at a different time is The coded block containing the center lower right position at the same position as the coded block to be processed in ColPic is set as the coded block colCb at a different time (step S4225). An example of this encoded block is shown in encoded block T1 in FIG. 49.

Refer to FIG. 50 again. Next, inter prediction information is derived for each reference list (steps S4203 and S4204). Here, for the coded block colCb, a motion vector mvLXCol for each reference list and a flag availableFlagLXCol indicating whether or not the coding information is valid are derived. LX indicates a reference list; in the derivation of reference list 0, LX becomes L0, and in the derivation of reference list 1, LX becomes L1. Derivation of inter prediction information will be explained with reference to FIG. 53.

If the coded block colCb at a different time is not available (step S4231: NO), or if the prediction mode PredMode is intra prediction (MODE_INTRA) (step S4232: NO), both the flag availableFlagLXCol and the flag predFlagLXCol are set to 0 (step S4233). , the motion vector mvLXCol is set to (0, 0) (step S4234), and the process ends.

If the encoded block colCb is available (step S4231: YES) and the prediction mode PredMode is not intra prediction (MODE_INTRA) (step S4232: YES), mvCol, refIdxCol, and availableFlagCol are calculated by the following procedure.

If the flag PredFlagL0[xPCol][yPCol] indicating whether L0 prediction is used for coding block colCb is 0 (step S4235: YES), the prediction mode of coding block colCb is Pred_L1, so the motion vector mvCol is set to the same value as MvL1[xPCol][yPCol], which is the L1 motion vector of coded block colCb (step S4236), and reference index refIdxCol is set to the same value as L1 reference index RefIdxL1[xPCol][yPCol]. is set (step S4237), and the reference list listCol is set to L1 (step S4238). Here, xPCol and yPCol are indices indicating the position of the upper left pixel of the coded block colCb in the picture ColPic at different times.

On the other hand, if the L0 prediction flag PredFlagL0[xPCol][yPCol] of the coding block colCb is not 0 (step S4235: NO), it is determined whether the L1 prediction flag PredFlagL1[xPCol][yPCol] of the coding block colCb is 0. do. If the L1 prediction flag PredFlagL1[xPCol][yPCol] of the coding block colCb is 0 (step S4239: YES), the motion vector mvCol is the same as the L0 motion vector MvL0[xPCol][yPCol] of the coding block colCb. The reference index refIdxCol is set to the same value as the reference index RefIdxL0[xPCol][yPCol] of L0 (step S4241), and the reference list listCol is set to L0 (step S4242).

If both the L0 prediction flag PredFlagL0[xPCol][yPCol] of the encoding block colCb and the L1 prediction flag PredFlagL1[xPCol][yPCol] of the encoding block colCb are not 0 (step S4235: NO and S4239: NO), encoding Since the inter prediction mode of block colCb is bi-prediction (Pred_BI), one of the two motion vectors L0 and L1 is selected (step S4243).

FIG. 54 is a flowchart showing a procedure for deriving inter prediction information of a coding block when the inter prediction mode of the coding block colCb is bi-prediction (Pred_BI).

First, it is determined whether the POC of all pictures registered in all reference lists is smaller than the POC of the current picture to be processed (step S4251), and all reference lists L0 and When the POC of all pictures registered in L1 is smaller than the POC of the current picture to be processed (step S4251: YES), LX is L0, that is, a predicted vector candidate for the motion vector of L0 of the coded block to be processed. (Step S4252: YES), selects the inter prediction information of L0 of the coding block colCb, and selects LX as L1, that is, the predictive vector candidate of the motion vector of L1 of the coding block to be processed. If it has been derived (step S4252: NO), the L1 inter prediction information of the coded block colCb is selected. On the other hand, if at least one of the POCs of pictures registered in all reference lists L0 and L1 of coding block colCb is larger than the POC of the current picture to be processed (step S4251: NO), and the flag collocated_from_l0_flag is 0 ( If the flag collocated_from_l0_flag is 1 (step S4253: YES), select the L0 inter prediction information of the coded block colCb, and select the L1 inter prediction information of the coded block colCb. .

When selecting inter prediction information for L0 of coding block colCb (step S4252: YES or step S4253: YES), motion vector mvCol is set to the same value as MvL0[xPCol][yPCol] (step S4254). , the reference index refIdxCol is set to the same value as RefIdxL0[xPCol][yPCol] (step S4255), and the list listCol is set to L0 (step S4256).

When selecting L1 inter prediction information of coding block colCb (step S4252: NO or step S4253: NO), motion vector mvCol is set to the same value as MvL1[xPCol][yPCol] (step S4257). , the reference index refIdxCol is set to the same value as RefIdxL1[xPCol][yPCol] (step S4258), and the list listCol is set to L1 (step S4259).

Returning to FIG. 53, once the inter prediction information is obtained from the encoded block colCb, both the flag availableFlagLXCol and the flag predFlagLXCol are set to 1 (step S4244).

Subsequently, the motion vector mvCol is scaled to become a motion vector mvLXCol (step S4245). The scaling calculation processing procedure for this motion vector mvLXCol will be explained using FIG. 55.

The inter-picture distance td is obtained by subtracting the POC of the reference picture corresponding to the reference index refIdxCol referenced in the list listCol of the coded block colCb from the POC of the picture ColPic at a different time.
td = [POC of picture ColPic at different time] - [POC of reference picture referenced in list Col of coded block colCb]
is calculated (step S4261). Note that if the POC of the reference picture referred to in the list listCol of coded block colCb is earlier than the picture ColPic of a different time in the display order, the inter-picture distance td will be a positive value, and If the POC of the reference picture referred to in the list listCol of the coded block colCb is later in the display order, the inter-picture distance td will be a negative value.

Next, the POC of the reference picture referred to by the list LX of the current picture to be processed is subtracted from the POC of the current picture to be processed to obtain the inter-picture distance tb.
tb = [POC of current picture to be processed] - [POC of reference picture corresponding to reference index of LX of temporal merging candidate]
is calculated (step S4262). Note that if the reference picture referred to in the list LX of current pictures to be processed is earlier than the current picture to be processed in the display order, the inter-picture distance tb will be a positive value, and the current picture in the list LX of pictures to be processed will be a positive value. If the reference picture referred to in is later in the display order, the inter-picture distance tb will be a negative value.

Next, the inter-picture distances td and tb are compared (step S4263), and if the inter-picture distances td and tb are equal (step S4263: YES), the motion vector mvLXCol is
mvLXCol = mvCol
is calculated (step S4264), and the present scaling calculation process ends.

On the other hand, if the inter-picture distances td and tb are not equal (step S4263: NO), the variable tx is
tx = ( 16384 + Abs( td ) >> 1 ) / td
(Step S4265). Next, set the scaling factor distScaleFactor to
distScaleFactor = Clip3( -4096, 4095, ( tb * tx + 32 ) >> 6 )
(Step S4266). Here, Clip3(x,y,z) is a function that limits the minimum value to x and the maximum value to y for the value z. Next, the motion vector mvLXCol is
mvLXCol = Clip3( -32768, 32767, Sign( distScaleFactor * mvLXCol )
* ((Abs( distScaleFactor * mvLXCol ) + 127 ) >> 8 ) )
is calculated (step S4267), and the present scaling calculation process is ended. Here, Sign(x) is a function that returns the sign of value x, and Abs(x) is a function that returns the absolute value of value x.

Refer to FIG. 50 again. Then, the motion vector mvL0Col of L0 is added as a candidate to the predicted motion vector candidate list mvpListLX in the normal predicted motion vector mode derivation unit 301 (step S4205). However, this addition is only possible when the flag availableFlagL0Col=1 indicates whether the coded block colCb of reference list 0 is valid. Furthermore, the motion vector mvL1Col of L1 is added as a candidate to the predicted motion vector candidate list mvpListLX in the normal predicted motion vector mode derivation unit 301 (step S4205). However, this addition is only possible when the flag availableFlagL1Col=1 indicates whether the coded block colCb of reference list 1 is valid. With the above steps, the processing of the temporal motion vector predictor candidate derivation unit 322 is completed.

The above description of the normal predicted motion vector mode deriving unit 301 is for encoding, but the same applies for decoding. That is, the operation of the temporally predicted motion vector candidate deriving unit 422 in the normal predicted motion vector mode deriving unit 401 in FIG. 23 will be similarly explained by replacing encoding with decoding in the above description.

<Derivation of time merge candidates>
The operation of the temporal merging candidate deriving section 342 in the normal merging mode deriving section 302 in FIG. 18 will be described with reference to FIG. 56.

First, ColPic is derived (step S4301). Next, a coded block colCb is derived and coded information is obtained (step S4302). Furthermore, inter prediction information is derived for each reference list (steps S4303 and S4304). The above processing is the same as S4201 to S4204 in the temporal motion vector predictor candidate derivation unit 322, so the explanation will be omitted.

Next, a flag availableFlagCol indicating whether the encoded block colCb is valid is calculated (step S4305). If the flag availableFlagL0Col or the flag availableFlagL1Col is 1, availableFlagCol is 1. Otherwise, availableFlagCol is 0.

Then, the motion vector mvL0Col of L0 and the motion vector mvL1Col of L1 are added as candidates to the merge candidate list mergeCandList in the normal merge mode deriving unit 302 described above (step S4306). However, this addition is only possible when the flag availableFlagCol=1 indicates whether or not the coded block colCb is valid. With the above, the processing of the temporal merging candidate deriving unit 342 is completed.

The above description of the temporal merging candidate deriving unit 342 is for encoding, but the same applies for decoding. That is, the operation of the temporal merging candidate deriving section 442 in the normal merging mode deriving section 402 in FIG. 24 will be similarly explained by replacing encoding with decoding in the above description.

<Update of historical predicted motion vector candidate list>
Next, a method for initializing and updating the history predicted motion vector candidate list HmvpCandList provided in the encoding information storage memory 111 on the encoding side and the encoding information storage memory 205 on the decoding side will be described in detail. FIG. 38 is a flowchart illustrating the history predicted motion vector candidate list initialization/update processing procedure.

In this embodiment, it is assumed that the historical predicted motion vector candidate list HmvpCandList is updated in the encoded information storage memory 111 and the encoded information storage memory 205. A history candidate list update unit may be installed in the inter prediction unit 102 and the inter prediction unit 203 to update the history predicted motion vector candidate list HmvpCandList.

The history predicted motion vector candidate list HmvpCandList is initialized at the beginning of the slice, and on the encoding side, the history predicted motion vector candidate list HmvpCandList is updated when the prediction method determining unit 105 selects the normal prediction vector mode or the normal merge mode. However, on the decoding side, when the inter prediction mode decoded by the bit string decoding unit 201 is the normal prediction vector mode or the normal merge mode, the history prediction motion vector candidate list HmvpCandList is updated.

Inter prediction information used when performing inter prediction in normal prediction vector mode or normal merge mode is registered as inter prediction information candidate hMvpCand in history prediction motion vector candidate list HmvpCandList. The inter prediction information candidate hMvpCand includes an L0 reference index refIdxL0, an L1 reference index refIdxL1, an L0 prediction flag predFlagL0 indicating whether L0 prediction is performed, and an L1 prediction flag predFlagL1 indicating whether L1 prediction is performed. A motion vector mvL0 of L0 and a motion vector mvL1 of L1 are included. Among the elements (i.e., inter prediction information) registered in the historical predicted motion vector candidate list HmvpCandList provided in the encoded information storage memory 111 on the encoding side and the encoded information storage memory 205 on the decoding side, there are inter prediction information candidates. If inter prediction information with the same value as hMvpCand exists, that element is deleted from the history predicted motion vector candidate list HmvpCandList. On the other hand, if there is no inter prediction information with the same value as the inter prediction information candidate hMvpCand, the first element of the historical predicted motion vector candidate list HmvpCandList is deleted, and the inter prediction information candidate is added to the end of the historical predicted motion vector candidate list HmvpCandList. Add hMvpCand.

The number of elements of the historical predicted motion vector candidate list HmvpCandList provided in the encoded information storage memory 111 on the encoding side and the encoded information storage memory 205 on the decoder side of the present invention is assumed to be six.

First, a history predicted motion vector candidate list HmvpCandList is initialized in units of slices (step S2101 in FIG. 38). At the beginning of the slice, all elements of the historical predicted motion vector candidate list HmvpCandList are emptied, and the value of NumHmvpCand, the number of historical predicted motion vector candidates registered in the historical predicted motion vector candidate list HmvpCandList, is set to 0.

Note that although we assumed that the history predicted motion vector candidate list HmvpCandList was initialized in units of slices (the first encoded block of a slice), it could also be initialized in units of pictures, tiles, tile groups, bricks, or tree block rows. It's okay.

Subsequently, the following process of updating the history predicted motion vector candidate list HmvpCandList is repeatedly performed for each encoded block within the slice (steps S2102 to S2107 in FIG. 38).

First, initial settings are performed for each encoded block. A value of FALSE is set for a flag specificCandExist indicating whether or not the same candidate exists, and a value of 0 is set for the deletion target index removeIdx (step S2103 in FIG. 38).

It is determined whether the inter prediction information candidate hMvpCand to be registered exists in the historical predicted motion vector candidate list HmvpCandList (step S2104 in FIG. 38). When the prediction method determining unit 105 on the encoding side determines that the mode is normal predicted motion vector mode or normal merge mode, or when the bit string decoding unit 201 on the decoding side decodes as the normal predicted motion vector mode or normal merge mode, Set the inter prediction mode to hMvpCand. If the prediction method determination unit 105 on the encoding side determines to be intra prediction mode, sub-block predicted motion vector mode, or sub-block merge mode, or the bit string decoding unit 201 on the decoding side determines intra prediction mode, sub-block predicted motion vector mode. Alternatively, when decoding is performed in sub-block merge mode, the history predicted motion vector candidate list HmvpCandList is not updated, and there is no inter prediction information candidate hMvpCand to be registered. If there is no inter prediction information candidate hMvpCand to be registered, steps S2105 to S2106 are skipped (step S2104 in FIG. 38: NO). If there is an inter prediction information candidate hMvpCand to be registered, the processes from step S2105 onwards are performed (step S2104 in FIG. 38: YES).

Next, it is determined whether the same element as the inter prediction information candidate hMvpCand to be registered exists in each element of the history predicted motion vector candidate list HmvpCandList (step S2105 in FIG. 38). FIG. 39 is a flowchart of this same element confirmation processing procedure. If the value of the number of history predicted motion vector candidates NumHmvpCand is 0 (step S2121 in FIG. 39: NO), the history prediction motion vector candidate list HmvpCandList is empty and there is no identical candidate, so steps S2122 to S2125 in FIG. 39 are skipped. , this identical element confirmation processing procedure ends. If the value of the number of historical predicted motion vector candidates NumHmvpCand is greater than 0 (step S2121 in FIG. 39: YES), the process in step S2123 is repeated until the historical predicted motion vector index hMvpIdx is from 0 to NumHmvpCand-1 (step S2121 in FIG. 39). S2122 to S2125). First, it is compared whether the hMvpIdx-th element HmvpCandList[hMvpIdx] counting from 0 in the history predicted motion vector candidate list is the same as the inter prediction information candidate hMvpCand (step S2123 in FIG. 39). If they are the same (step S2123 in FIG. 39: YES), set the flag identificationCandExist indicating whether the same candidate exists to a TRUE value, set the deletion target index removeIdx to the value of hMVpIndex, and delete the same candidate. End element confirmation processing. If they are not the same (step S2123 in FIG. 39: NO), hMvpIdx is incremented by 1, and if the historical predicted motion vector index hMvpIdx is less than or equal to NumHmvpCand-1, the processes from step S2123 onward are performed (steps S2122 to S2125 in FIG. 39). .

Returning to the flowchart in FIG. 38 again, the elements of the historical predicted motion vector candidate list HmvpCandList are shifted and added (step S2106 in FIG. 38). FIG. 40 is a flowchart of the element shift/addition processing procedure for the history predicted motion vector candidate list HmvpCandList in step S2106 in FIG. First, it is determined whether to add a new element after removing the elements stored in the history predicted motion vector candidate list HmvpCandList, or to add a new element without removing the elements. Specifically, it is compared whether the flag identificationCandExist indicating whether the same candidate exists is TRUE or NumHmvpCand is 6 (step S2141 in FIG. 40). If the flag identificationCandExist indicating whether the same candidate exists or not satisfies either the condition of TRUE or NumHmvpCand of 6 (step S2141 in FIG. 40: YES), the flag is stored in the history predicted motion vector candidate list HmvpCandList. Remove existing elements and add new elements. Set the initial value of index i to the value removeIdx + 1. The element shift process of step S2143 is repeated from this initial value to NumHmvpCand. (Steps S2142 to S2144 in FIG. 40). The elements of HmvpCandList[i] are copied to HmvpCandList[i - 1] to shift the elements forward (step S2143 in FIG. 40), and i is incremented by 1 (steps S2142 to S2144 in FIG. 40). When the index i becomes NumHmvpCand+1 and the element shift process in step S2143 is completed, the inter prediction information candidate hMvpCand is added to the end of the history predicted motion vector candidate list (step S2145 in FIG. 40). Here, the last of the history predicted motion vector candidate list is the (NumHmvpCand-1)th HmvpCandList[NumHmvpCand-1] counting from 0. This completes the element shift/addition process for the history predicted motion vector candidate list HmvpCandList. On the other hand, if the flag identificationCandExist indicating whether or not the same candidate exists does not satisfy either of the conditions of TRUE and NumHmvpCand of 6 (step S2141 in FIG. 40: NO), the flag is stored in the history predicted motion vector candidate list HmvpCandList. The inter prediction information candidate hMvpCand is added to the end of the history predicted motion vector candidate list without removing the elements that are currently displayed (step S2146 in FIG. 40). Here, the last of the history predicted motion vector candidate list is the NumHmvpCand-th HmvpCandList[NumHmvpCand] counting from 0. Further, NumHmvpCand is incremented by 1, and the element shift/addition process of the history predicted motion vector candidate list HmvpCandList is completed.

FIG. 43 is a diagram illustrating an example of the process of updating the historical predicted motion vector list. When adding new inter prediction information when six elements (inter prediction information) are registered in the history prediction motion vector candidate list HmvpCandList, each element of the history prediction motion vector candidate list HmvpCandList and the new inter prediction information from the front are registered. Comparing the prediction information (FIG. 43(a)), if the new inter prediction information has the same value as the third element HMVP2 from the beginning of the history prediction motion vector candidate list HmvpCandList, the new inter prediction information is selected from the history prediction motion vector candidate list HmvpCandList. Delete element HMVP2, shift (copy) backward elements HMVP3 to HMVP5 forward one by one, and add new inter prediction information to the end of the history predicted motion vector candidate list HmvpCandList (Figure 43(b)) , the update of the historical predicted motion vector candidate list HmvpCandList is completed (FIG. 43(c)).

<History predicted motion vector candidate derivation process>
Next, the history predicted motion vector candidate derivation unit 323 of the normal predicted motion vector mode derivation unit 301 on the encoding side and the history predicted motion vector candidate derivation unit 423 of the normal predicted motion vector mode derivation unit 401 on the decoding side perform a common process. A method for deriving historical predicted motion vector candidates from the historical predicted motion vector candidate list HmvpCandList, which is the processing procedure of step S304 in FIG. 20, will be described in detail. FIG. 41 is a flowchart illustrating the procedure for deriving historical predicted motion vector candidates.

If the current number of motion vector predictor candidates numCurrMvpCand is greater than or equal to the maximum number of elements (here, 2) of the motion vector predictor candidate list mvpListLX or the value of the number of historical motion vector predictor candidates NumHmvpCand is 0 (step S2201 in FIG. 41: NO), the processes from steps S2202 to S2209 in FIG. 41 are omitted, and the history predicted motion vector candidate derivation process procedure is ended. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX, and if the value of the number of historical motion vector predictor candidates NumHmvpCand is greater than 0 (step S2201 in FIG. 41: YES), steps S2202 to S2209 in FIG. 41 are performed.

Subsequently, the processes of steps S2203 to S2208 in FIG. 41 are repeated until the index i is from 1 to the smaller value of 4 or the number of history predicted motion vector candidates NumHmvpCand (steps S2202 to S2209 in FIG. 41).
If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the motion vector predictor candidate list mvpListLX (step S2203 in FIG. 41: NO), the processes from steps S2204 to S2209 in FIG. The history predicted motion vector candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX (step S2203 in FIG. 41: YES), the processes from step S2204 in FIG. 41 are performed.

Subsequently, the processes from steps S2205 to S2207 are performed for indexes Y of 0 and 1 (L0 and L1), respectively (steps S2204 to S2208 in FIG. 41). If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX (step S2205 in FIG. 41: NO), the processes from steps S2206 to S2209 in FIG. The history predicted motion vector candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX (step S2205 in FIG. 41: YES), the processes from step S2206 in FIG. 41 are performed.

Next, there is an element in which the reference index of LY in the historical motion vector predictor candidate list HmvpCandList[i] is the same as the reference index refIdxLX of the motion vector to be encoded/decoded, and is different from any element in the motion vector predictor list mvpListLX. (Step S2206 in FIG. 41: YES), as the last element of the motion vector predictor candidate list, the historical motion vector predictor candidate HmvpCandList[NumHmvpCand - i] is added to LY (step S2207 in FIG. 41), and the current number of motion vector predictor candidates numCurrMvpCand is incremented by one. Unless the reference index of LY in the historical motion vector predictor candidate list HmvpCandList[i] is the same as the reference index refIdxLX of the motion vector to be encoded/decoded, and there is an element that is different from any element in the motion vector predictor list mvpListLX. (Step S2206 in FIG. 41: NO), the additional processing in step S2207 is skipped.

The above processing from steps S2205 to S2207 in FIG. 41 is performed in both L0 and L1 (steps S2204 to S2208 in FIG. 41).

The index i is incremented by 1, and if the index i is less than the smaller value of 4 or the number of history predicted motion vector candidates NumHmvpCand, the process from step S2203 onward is performed again (steps S2202 to S2209 in FIG. 41).

<History merge candidate derivation process>
Next, the process of step S404 in FIG. 21 is a process common to the history merge candidate deriving unit 345 of the normal merge mode deriving unit 302 on the encoding side and the history merge candidate deriving unit 445 of the normal merge mode deriving unit 402 on the decoding side. The procedure for deriving history merge candidates from the history merge candidate list HmvpCandList will be described in detail. FIG. 42 is a flowchart illustrating the history merging candidate derivation processing procedure.

First, initialization processing is performed (step S2301 in FIG. 42). Set a value of FALSE to each element from 0 to (numCurrMergeCand -1) in isPruned[i], and set numCurrMergeCand, the number of elements registered in the current merge candidate list, to the variable numOrigMergeCand.

Next, the initial value of the index hMvpIdx is set to 1, and the additional processing from step S2303 to step S2310 in FIG. 42 is repeated from this initial value to NumHmvpCand (steps S2302 to S2311 in FIG. 42). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, and this history merge candidate is derived. The process ends (step S2303 in FIG. 42: NO). If the number numCurrMergeCand of elements registered in the current merge candidate list is less than or equal to (maximum number of merge candidates MaxNumMergeCand-1) (step S2303 in FIG. 42: YES), the processes from step S2304 onward are performed.

First, a value of FALSE is set for sameMotion (step S2304 in FIG. 42). Subsequently, the initial value of index i is set to 0, and steps S2306 and S2307 in FIG. 42 are performed from this initial value to 1 (S2305 to S2308 in FIG. 42).

Next, check whether the (NumHmvpCand-hMvpIdx)th element HmvpCandList[NumHmvpCand-hMvpIdx] counting from 0 in the history motion vector prediction candidate list and mergeCandList[i] the i-th element counting from 0 in the merging candidate list have the same value. A comparison is made to see if it is true or not (step S2306 in FIG. 42). Here, the merging candidates having the same value means that the values of all components (inter prediction mode, reference index, motion vector) of the merging candidates are the same. However, the process of step S2306 is limited to the case where hMvpIdx is larger than NumHmvpCand-2, mergeCandList[i] is a spatial merging candidate, and isPruned[i] is FALSE. If the values are the same (step S2306 in FIG. 39: YES), both sameMotion and isPruned[i] are set to TRUE (step S2307 in FIG. 42). If the values are not the same (step S2306 in FIG. 39: NO), the process in step S2307 is skipped. When the iterative processing from step S2305 to step S2308 in FIG. 42 is completed, it is compared whether or not sameMotion is FALSE (step S2309 in FIG. 42), and if sameMotion is FALSE (step S2309 in FIG. 42: YES), add the (NumHmvpCand - hMvpIdx)th element HmvpCandList[NumHmvpCand - hMvpIdx] of the history predicted motion vector candidate list to the numCurrMergeCand-th mergeCandList[numCurrMergeCand] of the merge candidate list, and increment numCurrMergeCand by 1 ( Step S2310 in FIG. 42). The index hMvpIdx is incremented by 1 (step S2302 in FIG. 42), and steps S2302 to S2311 in FIG. 42 are repeated.

When confirmation of all the elements in the history predicted motion vector candidate list is completed, or when merging candidates are added to all the elements in the merging candidate list, this history merging candidate derivation process is completed.

<Average merge candidate derivation process>
Next, the process of step S403 in FIG. 21 is a process common to the average merge candidate deriving unit 344 of the normal merge mode deriving unit 302 on the encoding side and the average merge candidate deriving unit 444 of the normal merge mode deriving unit 402 on the decoding side. The method of deriving the average merging candidates, which is a procedure, will be described in detail. FIG. 62 is a flowchart illustrating the average merging candidate derivation processing procedure.

First, initialization processing is performed (step S1301 in FIG. 62). Set the number of elements registered in the current merge candidate list numCurrMergeCand to the variable numOrigMergeCand.

Next, the merging candidate list is sequentially scanned from the beginning to determine two pieces of motion information. Let index i=0 indicating the first motion information, and index j=1 indicating the second motion information. (Steps S1302 to S1303 in FIG. 62). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, and this history merge candidate is derived. The process ends (step S1304 in FIG. 62). If the number numCurrMergeCand of elements registered in the current merge candidate list is less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), processing from step S1305 onwards is performed.

It is determined whether the i-th motion information mergeCandList[i] of the merge candidate list and the j-th motion information mergeCandList[j] of the merge candidate list are both invalid (step S1305 in FIG. 62), and both are invalid. In this case, the average merge candidates for mergeCandList[i] and mergeCandList[j] are not derived and the process moves to the next element. If both mergeCandList[i] and mergeCandList[j] are not invalid, the following process is repeated with X set to 0 and 1 (steps S1306 to S1314 in FIG. 62).

It is determined whether the LX prediction of mergeCandList[i] is valid (step S1307 in FIG. 62). If the LX prediction of mergeCandList[i] is valid, it is determined whether the LX prediction of mergeCandList[j] is valid (step S1308 in FIG. 62). If the LX prediction of mergeCandList[j] is valid, that is, if the LX prediction of mergeCandList[i] and the LX prediction of mergeCandList[j] are both valid, then the motion vector of the LX prediction of mergeCandList[i] and the mergeCandList Derive the average merging candidate of LX prediction that has the motion vector of LX prediction that is the average of the motion vector of LX prediction of [j] and the reference index of LX prediction of mergeCandList[i], set it to the LX prediction of averageCand, and set it to the LX prediction of averageCand. LX prediction is enabled (step S1309 in FIG. 62). In step S1308 of FIG. 62, if the LX prediction of mergeCandList[j] is not valid, that is, if the LX prediction of mergeCandList[i] is valid and the LX prediction of mergeCandList[j] is invalid, mergeCandList[i] An average merging candidate for LX prediction having a motion vector for LX prediction and a reference index is derived and set as the LX prediction for averageCand, and the LX prediction for averageCand is made valid (step S1310 in FIG. 62). If the LX prediction of mergeCandList[i] is not valid in step S1307 of FIG. 62, it is determined whether the LX prediction of mergeCandList[j] is valid (step S1311 of FIG. 62). If the LX prediction of mergeCandList[j] is valid, that is, if the LX prediction of mergeCandList[i] is invalid and the LX prediction of mergeCandList[j] is valid, then the motion vector of the LX prediction of mergeCandList[j] An average merging candidate for LX prediction having a reference index is derived and set as the averageCand LX prediction, and the averageCand LX prediction is made valid (step S1312 in FIG. 62). In step S1311 of FIG. 62, if the LX prediction of mergeCandList[j] is not valid, that is, if the LX prediction of mergeCandList[i] and the LX prediction of mergeCandList[j] are both invalid, the LX prediction of averageCand is invalidated. (Step S1312 in FIG. 62).

The average merge candidate averageCand of the L0 prediction, L1 prediction, or BI prediction generated as described above is added to the numCurrMergeCand-th mergeCandList[numCurrMergeCand] of the merge candidate list, and numCurrMergeCand is incremented by 1 (step S1315 in FIG. 62). This completes the process of deriving average merging candidates.

Note that the average merging candidate is averaged for each of the horizontal component of the motion vector and the vertical component of the motion vector.

<Derivation of sub-block time merging candidates>
The operation of sub-block time merge candidate deriving section 381 in sub-block merging mode deriving section 304 of FIG. 16 will be described with reference to FIG. 44.

First, it is determined whether the encoded block has less than 8x8 pixels (step S4002).

If the encoded block is less than 8x8 pixels (step S4002: YES), a flag indicating the existence of a sub-block time merging candidate is set to availableFlagSbCol=0 (step S4003), and the processing of the sub-block time merging candidate deriving unit is ended. . Here, if temporal motion vector prediction is prohibited by the syntax or subblock temporal merging is prohibited, the same processing as in the case where the encoded block is less than 8x8 pixels (step S4002: YES) is performed. do.

On the other hand, if the encoded block is 8x8 pixels or more (step S4002: NO), adjacent motion information of the encoded block in the encoded picture is derived (step S4004).

The process of deriving adjacent motion information of a coded block will be described with reference to FIG. 45. The process of deriving adjacent motion information is similar to the process of the spatially predicted motion vector candidate deriving unit 321 described above. However, the order in which adjacent blocks are searched is A0, B0, B1, A1, and B2 is not searched. First, encoding information is acquired as adjacent block n=A0 (step S4052). The encoding information indicates a flag availableFlagN indicating whether or not adjacent blocks can be used, a reference index refIdxLXN for each reference list, and a motion vector mvLXN.

Next, it is determined whether adjacent block n is valid or invalid (step S4054). If the flag indicating whether the adjacent block is available or not is availableFlagN=1, it is valid, and otherwise it is invalid.

If the adjacent block n is valid (step S4054: YES), the reference index refIdxLXN is set as the reference index refIdxLXn of the adjacent block n (step S4056). Further, the motion vector mvLXN is set as the motion vector mvLXn of the adjacent block n (step S4056), and the process of deriving the adjacent motion information of the block is ended.

On the other hand, if the adjacent block n is invalid (step S4054: NO), the adjacent block n=B0, the encoding information is acquired (step S4052), and it is determined whether the adjacent block n is valid or invalid (step S4054). . Hereafter, the same process is performed and the loop is performed in the order of B1 and A1. The process of deriving the adjacent motion information loops until the adjacent block becomes valid, and if all the adjacent blocks A0, B0, B1, A1 are invalid, the process of deriving the adjacent motion information of the block ends.

Refer to FIG. 44 again. After deriving the adjacent motion information (step S4004), a temporal motion vector is derived (step S4006).

The process of deriving a temporal motion vector will be described with reference to FIG. 46. First, the temporal motion vector tempMv=(0,0) is initialized (step S4062).

Next, it is determined whether the adjacent motion information is valid or invalid (step S4064). If the flag indicating whether the adjacent block is available or not is availableFlagN=1, it is valid, and otherwise it is invalid. If the adjacent motion information is invalid (step S4064: NO), the process of deriving the temporal motion vector ends.

On the other hand, if the adjacent motion information is valid (step S4064: YES), it is determined whether a flag predFlagL1N indicating whether L1 prediction is used in the adjacent block N is 1 (step S4066). If predFlagL1N=0 (step S4066: NO), proceed to the next process (step S4078). If predFlagL1N=1 (step S4066: YES), it is determined whether the POC of all pictures registered in all reference lists is less than or equal to the POC of the current picture to be processed (step S4068). If this determination is true (step S4068: YES), the process advances to the next process (step S4070).

If the slice type slice_type is B slice and the flag collocated_from_l0_flag is 0 (step S4070: YES, step and S4072: YES), determine whether ColPic and reference picture RefPicList1[refIdxL1N] (picture with reference index refIdxL1N of reference list L1) are the same. (Step S4074). If this determination is true (step S4074: YES), the temporal motion vector tempMv=mvL1N is set (step S4076). If this determination is false (step S4074: NO), the process advances to the next process (step S4078). If the slice type slice_type is not a B slice and the flag collocated_from_l0_flag is not 0 (step S4070: NO or step S4072: NO), the process advances to the next process (step S4078).

Then, it is determined whether a flag predFlagL0N indicating whether L0 prediction is used in the adjacent block N is 1 (step S4078). If predFlagL0N=1 (step S4078: YES), it is determined whether ColPic and the reference picture RefPicList0[refIdxL0N] (the picture with the reference index refIdxL0N of the reference list L0) are the same (step S4080). If this determination is true (step S4080: YES), the temporal motion vector tempMv=mvL0N is set (step S4082). If this determination is false (step S4080: NO), the process of deriving the temporal motion vector ends.

Refer to FIG. 44 again. Next, ColPic is derived (step S4016). This process is the same as S4201 in the temporal motion vector predictor candidate derivation unit 322, so the explanation will be omitted.

Then, coded blocks colCb at different times are set (step S4017). This is to set the coded block located at the lower right of the center at the same position as the coded block to be processed in the picture ColPic at a different time as colCb. This encoded block corresponds to encoded block T1 in FIG. 49.

Next, the position where the temporal motion vector tempMv is added to the encoded block colCb is set as a new colCb (step S4018). Now, assume that the upper left position of encoded block colCb is (xColCb, yColCb), and the temporal motion vector tempMv is (tempMv[0], tempMv[1]) with 1/16 pixel precision. and,
xColCb = Clip3( xCtb, xCtb + CtbSizeY + 3, xColCb + ( tempMv[0] >> 4 ) )
yColCb = Clip3( yCtb, yCtb + CtbSizeY - 1, yColCb + ( tempMv[1] >> 4 ) )
Calculate. Here, the upper left position of the tree block is (xCtb, yCtb), and the size of the tree block is CtbSizeY. The coded block on ColPic that includes the position ((xColCb >> 3) << 3, (yColCb >> 3) << 3) becomes a new colCb. As shown in the above equation, the position after adding tempMv is corrected to a range approximately equal to the size of the tree block so that it does not deviate much compared to before adding tempMv. If this position is outside the screen, it will be corrected to within the screen.

Then, it is determined whether the prediction mode PredMode of this coded block colCb is inter prediction (MODE_INTER) (step S4020). If the prediction mode of colCb is not inter prediction (step S4020: NO), a flag indicating the existence of a sub-block time merging candidate is set to availableFlagSbCol=0 (step S4003), and the processing of the sub-block time merging candidate deriving unit is ended. .

On the other hand, if the prediction mode of colCb is inter prediction (step S4020: YES), inter prediction information is derived for each reference list (steps S4022, S4023). Here, for colCb, a central motion vector ctrMvLX for each reference list and a flag ctrPredFlagLX indicating whether LX prediction is used are derived. LX indicates a reference list; in the derivation of reference list 0, LX becomes L0, and in the derivation of reference list 1, LX becomes L1. Derivation of inter prediction information will be described with reference to FIG. 47.

If the coded block colCb at a different time is not available (step S4112: NO) or if the prediction mode PredMode is intra prediction (MODE_INTRA) (step S4114: NO), both the flag availableFlagLXCol and the flag predFlagLXCol are set to 0 (step S4116). , the motion vector mvCol is set to (0, 0) (step S4118), and the inter prediction information derivation process ends.

If the encoded block colCb is available (step S4112: YES) and the prediction mode PredMode is not intra prediction (MODE_INTRA) (step S4114: YES), mvCol, refIdxCol, and availableFlagCol are calculated by the following procedure.

If the flag PredFlagLX[xPCol][yPCol] indicating whether LX prediction of coding block colCb is used is 1 (step S4120: YES), the motion vector mvCol is the LX motion vector of coding block colCb. MvLX[xPCol][yPCol] is set to the same value (step S4122), the reference index refIdxCol is set to the same value as the reference index RefIdxLX[xPCol][yPCol] of LX (step S4124), and the list listCol is set to LX. (Step S4126). Here, xPCol and yPCol are indices indicating the position of the upper left pixel of the coded block colCb in the picture ColPic at different times.

On the other hand, if the flag PredFlagLX[xPCol][yPCol] indicating whether LX prediction of the coded block colCb is used is 0 (step S4120: NO), the following processing is performed. First, it is determined whether the POC of all pictures registered in all reference lists is less than or equal to the POC of the current picture to be processed (step S4128). Then, it is determined whether a flag PredFlagLY[xPCol][yPCol] indicating whether LY prediction of colCb is used is 1 (step S4128). Here, LY prediction is defined as a reference list different from LX prediction. In other words, when LX=L0, LY=L1, and when LX=L1, LY=L0.

If this determination is true (step S4128: YES), the motion vector mvCol is set to the same value as MvLY[xPCol][yPCol], which is the motion vector of LY of the coding block colCb (step S4130), and the reference index refIdxCol is The reference index RefIdxLY[xPCol][yPCol] of LY is set to the same value (step S4132), and the list listCol is set to LX (step S4134).

On the other hand, if this determination is false (step S4128: NO), the flag availableFlagLXCol and the flag predFlagLXCol are both set to 0 (step S4116), the motion vector mvCol is set to (0,0) (step S4118), and inter prediction information derivation processing is performed. end.

When inter prediction information is obtained from the encoded block colCb, both the flag availableFlagLXCol and the flag predFlagLXCol are set to 1 (step S4136).

Subsequently, the motion vector mvCol is scaled to become a motion vector mvLXCol (step S4138). This process is the same as S4245 in the temporal motion vector predictor candidate derivation unit 322, so the explanation will be omitted.

Refer to FIG. 44 again. After deriving the inter prediction information for each reference list, the calculated motion vector mvLXCol is set as the center motion vector ctrMvLX, and the calculated flag predFlagLXCol is set as the flag ctrPredFlagLX (steps S4022 and S4023).

Then, it is determined whether the central motion vector is valid or invalid (step S4024). It is judged as invalid if ctrPredFlagL0=0 and ctrPredFlagL1=0, otherwise it is judged as invalid. If the central motion vector is invalid (step S4024: NO), a flag indicating the existence of a sub-block temporal merging candidate is set to availableFlagSbCol=0 (step S4003), and the processing of the sub-block temporal merging candidate deriving unit is ended.

On the other hand, if the central motion vector is valid (step S4024: YES), a flag indicating the existence of a sub-block time merging candidate is set to availableFlagSbCol=1 (step S4025), and sub-block motion information is derived (step S4026). This process will be explained with reference to FIG. 48.

First, the number of subblocks numSbX in the width direction and the number numSbY of subblocks in the height direction are calculated from the width cbWidth and height cBheight of the encoded block colCb (step S4152). Further, refIdxLXSbCol=0 is set (step S4152). After this process, the process is repeated in units of prediction subblock colSb. This process is repeated while changing the index ySbIdx in the height direction from 0 to numSbY and the index xSbIdx in the width direction from 0 to numSbX.

If the upper left position of encoded block colCb is (xCb, yCb), then the upper left position (xSb, ySb) of prediction subblock colSb is
xSb = xCb + xSbIdx * sbWidth
ySb = yCb + ySbIdx * sbHeight
It is calculated as follows. Next, the position where the temporal motion vector tempMv is added to the prediction sub-block colSb is set as a new colSb (step S4154). If the upper left position of the prediction subblock colSb is (xColSb, yColSb) and the temporal motion vector tempMv is (tempMv[0], tempMv[1]) with 1/16 pixel precision, the new upper left position of colSb is
xColSb = Clip3( xCtb, xCtb + CtbSizeY + 3, xSb + ( tempMv[0] >> 4 ) )
yColSb = Clip3( yCtb, yCtb + CtbSizeY - 1, ySb + ( tempMv[1] >> 4 ) )
becomes. Here, the upper left position of the tree block is (xCtb, yCtb), and the size of the tree block is CtbSizeY. As shown in the above equation, the position after adding tempMv is corrected to a range approximately equal to the size of the tree block so that it does not deviate much compared to before adding tempMv. If this position is outside the screen, it will be corrected to within the screen.

Then, inter prediction information is derived for each reference list (steps S4156, S4158). Here, for the prediction subblock colSb, a motion vector mvLXSbCol for each reference list and a flag availableFlagLXSbCol indicating whether or not the prediction subblock is valid are derived for each subblock. LX indicates a reference list; in the derivation of reference list 0, LX becomes L0, and in the derivation of reference list 1, LX becomes L1. The derivation of inter prediction information is the same as S4022 and S4023 in FIG. 47, so the explanation will be omitted.

After deriving the inter prediction information (steps S4156, S4158), it is determined whether the prediction subblock colSb is valid (step S4160). If availableFlagL0SbCol=0 and availableFlagL1SbCol=0, colSb is invalid, otherwise it is determined to be valid. If colSb is invalid (step S4160: NO), the motion vector mvLXSbCol is set as the center motion vector ctrMvLX (step S4162). Furthermore, the flag predFlagLXSbCol indicating whether or not LX prediction is used is set to the flag ctrPredFlagLX in the central motion vector (step S4162). This completes the derivation of sub-block motion information.

Refer to FIG. 44 again. Then, the motion vector mvL0SbCol of L0 and the motion vector mvL1SbCol of L1 are added as candidates to the subblock merging candidate list subblockMergeCandList in the subblock merging mode deriving unit 304 (step S4028). However, this addition is only possible when the flag availableSbCol=1 indicates the existence of a subblock time merging candidate. With the above, the processing of the temporal merging candidate deriving unit 342 ends.

The above description of the sub-block time merging candidate deriving unit 381 is for encoding, but the same applies for decoding. That is, the operation of the sub-block time merging candidate deriving section 481 in the sub-block merging mode deriving section 404 in FIG. 22 will be explained in the same manner by replacing encoding with decoding in the above description.

<Motion compensation prediction processing>
The motion compensation prediction unit 306 acquires the position and size of the block currently being subjected to prediction processing during encoding. Further, the motion compensation prediction unit 306 acquires inter prediction information from the inter prediction mode determination unit 305. A reference index and a motion vector are derived from the obtained inter prediction information, and the reference picture specified by the reference index in the decoded image memory is moved from the same position as the image signal of the prediction block by the amount of the motion vector. Generate a predicted signal after acquiring the signal.

When the inter prediction mode in inter prediction is prediction from a single reference picture, such as L0 prediction or L1 prediction, the prediction signal obtained from one reference picture is used as the motion compensated prediction signal, and the inter prediction mode is BI. When the prediction mode is prediction from two reference pictures, such as prediction, the weighted average of the prediction signals obtained from the two reference pictures is used as the motion compensation prediction signal, and the motion compensation prediction signal is used to determine the prediction method. supply to the department. Although the weighted average ratio of bi-prediction is set to 1:1 here, the weighted average may be performed using other ratios. For example, the closer the picture interval between the picture to be predicted and the reference picture, the greater the weighting ratio. Further, the weighting ratio may be calculated using a correspondence table between combinations of picture intervals and weighting ratios.

The motion compensation prediction unit 406 has the same function as the motion compensation prediction unit 306 on the encoding side. The motion compensation prediction unit 406 receives the inter prediction information from the normal predicted motion vector mode deriving unit 401 , the normal merge mode deriving unit 402 , the sub-block predicted motion vector mode deriving unit 403 , and the sub-block merge mode deriving unit 404 through the switch 408 . Get it through.

The motion compensation prediction unit 406 supplies the obtained motion compensation prediction signal to the decoded image signal superimposition unit 207.

<About inter prediction mode>
The process of making predictions from a single reference picture is defined as uni-prediction, and in the case of uni-prediction, one of the two reference pictures registered in reference lists L0 and L1, called L0 prediction or L1 prediction, is used. Make predictions. The L0 prediction and the L1 prediction may be forward prediction (prediction that refers to a forward reference image) or backward prediction (prediction that refers to a backward reference image). 57 to 58 are diagrams for explaining motion compensated prediction in L0 prediction (uniprediction).

FIG. 57 shows a case where the inter prediction mode is L0 prediction and the L0 reference picture (RefL0Pic) is at a time earlier than the processing target picture (CurPic). FIG. 58 shows L0 prediction where the L0 reference picture is at a later time than the processing target picture. Similarly, uni-prediction can be performed by replacing the reference picture for L0 prediction in FIGS. 57 and 58 with the reference picture for L1 prediction (RefL1Pic).

A process of making predictions from two reference pictures is defined as bi-prediction, and in the case of bi-prediction, it is expressed as bi-prediction using both L0 prediction and L1 prediction. 59 to 61 are diagrams for explaining motion compensated prediction in bi-prediction. FIG. 59 shows a case of bi-prediction in which the reference picture for L0 prediction is at a time before the picture to be processed, and the reference picture for L1 prediction is at a time after the picture to be processed. FIG. 60 shows a case where bi-prediction is used, and the reference picture for L0 prediction and the reference picture for L1 prediction are at a time earlier than the processing target picture. FIG. 61 shows a case in which the reference picture for L0 prediction and the reference picture for L1 prediction are located at a later time than the processing target picture in bi-prediction.

In this way, the relationship between L0/L1 prediction types and time is limited to that L0 is forward prediction (prediction that refers to the forward reference image) and L1 is backward prediction (prediction that refers to the backward reference image). It can be used without being Furthermore, in the case of bi-prediction, the same reference picture may be used for each of L0 prediction and L1 prediction. Note that the determination of whether to perform motion compensation prediction using uni-prediction or bi-prediction is made based on information (for example, a flag) indicating whether to use L0 prediction and whether to use L1 prediction, for example. Ru.

<About reference index>
In an embodiment of the present invention, in order to improve the accuracy of motion compensated prediction, it is possible to select an optimal reference picture from among a plurality of reference pictures in motion compensated prediction. Therefore, the reference picture used in motion compensation prediction is used as a reference index, and the reference index is encoded in the encoded stream together with the encoded vector.

<Motion compensation processing based on normal predicted motion vector mode>
As shown in the inter prediction unit 102 on the encoding side in FIG. acquires this inter prediction information from the inter prediction mode determination unit 305, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensated prediction signal. The generated motion compensated prediction signal is supplied to the prediction method determining section 105.

Similarly, as shown in the inter prediction unit 203 on the decoding side in FIG. 22, the motion compensation prediction unit 406 normally The predicted motion vector mode derivation unit 401 obtains inter prediction information, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensated prediction signal. The generated motion compensated prediction signal is supplied to the decoded image signal superimposing section 207.

<Motion compensation processing based on normal merge mode>
As shown in the inter prediction unit 102 on the encoding side in FIG. 16, the motion compensation prediction unit 306, when the inter prediction information by the normal merge mode derivation unit 302 is selected in the inter prediction mode determination unit 305, This inter prediction information is acquired from the inter prediction mode determination unit 305, and the inter prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensated prediction signal is generated. The generated motion compensated prediction signal is supplied to the prediction method determining section 105.

Similarly, as shown in the inter prediction unit 203 on the decoding side in FIG. The derivation unit 402 acquires inter prediction information, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensated prediction signal. The generated motion compensated prediction signal is supplied to the decoded image signal superimposing section 207.

<Motion compensation processing based on sub-block predicted motion vector mode>
As shown in the inter prediction unit 102 on the encoding side in FIG. 16, the motion compensation prediction unit 306 detects when the inter prediction information by the sub-block prediction motion vector mode derivation unit 303 is selected in the inter prediction mode determination unit 305. In this step, this inter prediction information is acquired from the inter prediction mode determination unit 305, and the inter prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensated prediction signal is generated. The generated motion compensated prediction signal is supplied to the prediction method determining section 105.

Similarly, as shown in the inter prediction unit 203 on the decoding side in FIG. 22, the motion compensation prediction unit 406 performs The sub-block predicted motion vector mode derivation unit 403 acquires inter prediction information, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensated prediction signal. The generated motion compensated prediction signal is supplied to the decoded image signal superimposing section 207.

<Motion compensation processing based on sub-block merge mode>
As shown in the inter prediction unit 102 on the encoding side in FIG. , this inter prediction information is acquired from the inter prediction mode determining unit 305, and the inter prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensated prediction signal is generated. The generated motion compensated prediction signal is supplied to the prediction method determining section 105.

Similarly, as shown in the inter prediction unit 203 on the decoding side in FIG. The merge mode deriving unit 404 acquires inter prediction information, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensated prediction signal. The generated motion compensated prediction signal is supplied to the decoded image signal superimposing section 207.

<Motion compensation processing based on affine mode>
In this embodiment, motion compensation using an affine model can be used. Motion compensation using an affine model uses two to four corners of a coded block as control points, derives the motion vector of a subblock from the motion vector of the control point, and performs motion compensation on a subblock basis.

The following flags are reflected in the following flags based on the inter prediction conditions determined by the inter prediction mode determination unit 305 in the encoding process, and are encoded into the encoded stream. In the decoding process, it is determined whether motion compensation using an affine model is to be performed based on the following flags in the encoded stream.

sps_affine_enabled_flag indicates whether motion compensation using an affine model can be used in inter prediction. If sps_affine_enabled_flag is 0, motion compensation using an affine model is suppressed on a sequence-by-sequence basis. Also, inter_affine_flag and cu_affine_type_flag are not transmitted in the CU (coding unit) syntax of the encoded video sequence. If sps_affine_enabled_flag is 1, affine model motion compensation can be used in the encoded video sequence.

sps_affine_type_flag indicates whether motion compensation using 6-parameter affine mode can be used in inter prediction. The 6-parameter affine model is a mode in which a motion vector of a sub-block is derived from six parameters of horizontal and vertical components of the motion vector of three control points, and motion compensation is performed in units of sub-blocks. Motion vectors are derived for each subblock, but a common reference index is derived for each encoded block.

If sps_affine_type_flag is 0, motion compensation is suppressed so that it is not a 6-parameter affine model. Also, cu_affine_type_flag is not transmitted in the CU syntax of the encoded video sequence. If sps_affine_type_flag is 1, motion compensation using a 6-parameter affine model can be used in the encoded video sequence.

If sps_affine_type_flag does not exist, it is assumed to be 0.

When decoding a P or B slice, if inter_affine_flag is 1 in the CU currently being processed, an affine model is used to generate a motion compensated prediction signal for the CU currently being processed. Motion compensation is used.

If inter_affine_flag is 0, no affine model will be used for the CU currently being processed.

If inter_affine_flag does not exist, it is assumed to be 0.

When decoding a P or B slice, if cu_affine_type_flag is 1 in the CU currently being processed, the 6-parameter affine Model-based motion compensation is used.

If cu_affine_type_flag is 0, motion compensation using a four-parameter affine model is used to generate a motion compensated prediction signal for the CU currently being processed. The 4-parameter affine model is a mode in which a sub-block motion vector is derived from four parameters, ie, a horizontal component and a vertical component, of the motion vector of two control points, and motion compensation is performed in sub-block units.

<Merge difference motion vector (MMVD)>
The differential motion vector can be added to the motion vectors of the top two merging candidates (merging candidates with merging indexes of 0 and 1 in the merging candidate list). This differential motion vector is called a merged differential motion vector.

When the merge candidate selection unit 347 on the encoding side adds the merge difference motion vector, the motion vector to which the merge difference motion vector has been added is supplied to the motion compensation prediction unit 306 via the inter prediction mode determination unit 305. Further, the bit string encoding unit 108 encodes information regarding the merged difference motion vector. The information regarding the merge difference motion vector is an index mmvd_distance_idx indicating the distance to be added to the motion vector, and an index mmvd_direction_idx indicating the direction to add the motion vector. These indexes are defined as shown in the tables shown in FIGS. 63(a) and 63(b). Then, if the x and y components of the merged difference motion vector offset MmvdOffset are expressed as MmvdOffset[0] and MmvdOffset[1], respectively,
MmvdOffset[0] = ( MmvdDistance << 2 ) * MmvdSign[0]
MmvdOffset[1] = ( MmvdDistance << 2 ) * MmvdSign[1]
becomes. The merge difference motion vector is derived from the merge difference motion vector offset MmvdOffset in the above equation. Details of deriving the merged difference motion vector will be explained in the case of the decoding side below.

On the decoding side, if a merged differential motion vector exists, information regarding the merged differential motion vector is separated from the bitstream supplied to the bit string decoding unit 201, and a merged differential motion vector offset MmvdOffset is derived. Furthermore, the merge candidate selection unit 447 derives a merge difference motion vector from the decoded merge difference motion vector offset. This merge difference motion vector is added to the motion vector, and then the motion vector is supplied to the motion compensation prediction unit 406.

The derivation of the merge difference motion vector mMvdLX in the merge candidate selection unit 447 will be described with reference to the flowchart in FIG. 64(a). First, it is determined whether the inter prediction mode of the encoded block is bi-prediction (PRED_BI) (S4402). If it is not bi-prediction (S4402: No), it is determined whether it is L0 prediction (PRED_L0) (S4404). In the case of L0 prediction (S4404: Yes),
mmvdL0 = MmvdOffset
mmvdL1 = 0
(S4406), and the process of deriving the merged difference motion vector ends. In the case of L1 prediction (S4404: No),
mmvdL0 = 0
mmvdL1 = MmvdOffset
(S4408), and the process of deriving the merged difference motion vector ends.

On the other hand, in the case of bi-prediction (S4402: Yes), the difference between the POC of the processing target picture currPic and the reference picture is calculated for each reference list and set as currPocDiffL0 and currPocDiffL1, respectively (S4410). Here, the difference in POC between picA and picB, DiffPicOrderCnt(picA, picB), is
DiffPicOrderCnt( picA, picB ) = [POC of picA] - [POC of picB]
shows. Further, the reference picture RefPicList0[refIdxL0] is a picture indicated by the reference index refIdxL0 of the reference list L0. Similarly, reference picture RefPicList1[refIdxL1] is a picture indicated by reference index refIdxL1 of reference list L1.

Next, it is determined whether -currPocDiffL0 * currPocDiffL1 >= 0 (step S4412). If this determination is true (step S4412: Yes),
mmvdL0 = MmvdOffset
mmvdL1 = -MmvdOffset
(step S4414), and the process of deriving the merged difference motion vector ends. On the other hand, if this determination is false (step S4412: No),
mmvdL0 = MmvdOffset
mmvdL1 = MmvdOffset
(Step S4416). Next, it is determined whether the absolute value of the difference in POC with reference list L0 is greater than or equal to the absolute value of the difference in POC with reference list L1 (step S4418). If this determination is true (step S4418: Yes), set X=0, Y=1 (step S4420), and scale the merged difference motion vector mmvdL1 of L1 (step S4424). Here, mMvdLY indicates that when Y=0, it is mMvdL0, and when Y=1, it is mMvdL1. On the other hand, if this determination is false (step S4418: No), set X=1, Y=0 (step S4422), and scale the merged difference motion vector mmvdL0 of L0 (step S4424). The scaling of the merged difference motion vector mmvdLY is as shown in Figure 64(b).
td = Clip3( -128, 127, currPocDiffLX )
tb = Clip3( -128, 127, currPocDiffLY )
tx = ( 16384 + Abs( td ) >> 1 ) / td
distScaleFactor = Clip3( -4096, 4095, ( tb * tx + 32 ) >> 6 )
mMvdLY = Clip3( -32768, 32767, Sign( distScaleFactor * mMvdLY )
* ((Abs( distScaleFactor * mMvdLY ) + 127 ) >> 8 ) )
Derive it as Here, currPocDiffLX indicates currPocDiffL0 when X=0, and currPocDiffL1 when X=1. Similarly, currPocDiffLY indicates currPocDiffL0 when Y=0 and currPocDiffL1 when Y=1. Further, Clip3(x,y,z) is a function that limits the minimum value to x and the maximum value to y for the value z. Sign(x) is a function that returns the sign of value x, and Abs(x) is a function that returns the absolute value of value x. With the above steps, the process of deriving the merged difference motion vector is completed.

The merge difference motion vector may be added to the top two motion vectors of the sub-block merging candidates. In this case, the index mmvd_distance_idx indicating the distance to be added to the motion vector is defined as in the table shown in FIG. 63(c). The operation of the sub-block merging candidate selection unit 386 is the same as that of the merging candidate selection unit 347, so the explanation will be omitted. Furthermore, since the operation of the sub-block merging candidate selection unit 486 is the same as that of the merging candidate selection unit 447, a description thereof will be omitted.

As described above, MmvdDistance is defined as shown in the tables shown in FIGS. 63(a) and 63(c). Since these tables are defined with quarter pixel precision, the merged difference motion vectors that are generated may include fractional pixel precision. However, by encoding/decoding the flag indicating that the pixel precision in these tables is 1 in slice units, it is possible to change the generated merged difference motion vector so that it does not include fractional pixel precision. .

<Adaptive motion vector resolution (AMVR)>
The resolution of the differential motion vector can be adaptively changed in units of encoded blocks. This resolution is called adaptive motion vector resolution.

A case where adaptive motion vector resolution is used for the normal predicted motion vector mode will be described. In this case, the derived candidate motion vectors are calculated in the spatial predicted motion vector candidate deriving units 321 and 421, the temporal predicted motion vector candidate deriving units 322 and 422, and the historical predicted motion vector candidate deriving units 323 and 423. It is rounded. The resolution can be selected from 1/4, 1, and 4 pixel precision, and if you do not change the resolution, it will be 1/4 pixel precision. The rounding process is performed in accordance with the resolution of the motion vector in the encoded block to be processed. In other words, the derived candidate motion vector mvX is
rightShift = leftShift = MvShift + 2
offset = 1 << ( rightShift - 1 )
mvX = ( mvX >= 0 ? ( mvX + offset ) >> rightShift :
- ( (- mvX + offset ) >> rightShift ) ) << leftShift
is rounded off. Here, if the resolution of the motion vector in the encoded block to be processed is 1/4 pixel precision, MvShift=0. Similarly, when the motion vector resolution is 1 pixel precision, MvShift=2, and when the motion vector resolution is 4 pixel precision, MvShift=4. According to the above formula, each of the x and y components of mvX is processed.

Adaptive motion vector resolution can also be used for sub-block predicted motion vector modes. In this case, only the resolution differs from the normal predicted motion vector mode described above. That is, in the affine inheritance predicted motion vector candidate deriving units 361 and 461, the affine construction predicted motion vector candidate deriving units 362 and 462, and the affine identical predicted motion vector candidate deriving units 363 and 463, the derived candidate motion vectors are calculated based on the resolution. rounded accordingly. The resolution can be selected from 1/16, 1/4, and 1 pixel precision, and if you do not change the resolution, it will be 1/16 pixel precision. The rounding process is performed in accordance with the resolution of the motion vector in the encoded block to be processed. That is, the derived candidate motion vector mvX is rounded according to the above formula. Here, if the resolution of the motion vector in the encoded block to be processed is 1/4 pixel precision, MvShift=0. Similarly, if the motion vector resolution is 1 pixel precision, MvShift=2. Each of the x and y components of mvX is processed by the above formula.

The present embodiment may also be configured such that the order of reference when using the historical predicted motion vector candidate list is reverse to the order of storage. Here, if the history predicted motion vector candidate list is stored from the tail end, and the motion information on the head side of the history prediction motion vector candidate list is stored in the order that it is older than the motion information on the tail side, then The storage state is the same as in this embodiment. Furthermore, if the history predicted motion vector candidate list is stored in such a way that the head side is newer motion information than the tail side, the storage state will be opposite to that shown in this embodiment. Even in the case of such a reverse storage state, by performing the reference order in the reverse order of the storage order, the reference contents as shown in this embodiment, that is, the history predicted motion vector candidate list When referring to the motion information, it is possible to refer to the newly added motion information in order from the oldest motion information to the newly added motion information. Furthermore, when using the history predicted motion vector candidate list, the reference order is configured to be used either in the same direction as the storage order or in the reverse order from the storage order. It's okay. In other words, there is a case where the motion information stored in the history predicted motion vector candidate list can be referred to in order from the oldest motion information to newly added motion information, and a case where the motion information stored in the history prediction motion vector candidate list is When using the history predicted motion vector candidate list, the configuration may be configured such that the historical predicted motion vector candidate list is used in two cases: 1) to be able to sequentially refer to the oldest motion information from the newly added motion information;

Further, when adding a new element to the historical predicted motion vector candidate list, the configuration may be such that the process of searching and deleting elements having the same information from the historical predicted motion vector candidate list is not performed.

Furthermore, in normal motion vector predictor mode, when deriving normal motion vector predictor candidates using the historical motion vector predictor candidate list HmvpCandList, elements with the same information are searched from the historical motion vector predictor candidate list, and It may also be configured such that a process that does not normally use an element with information as a predicted motion vector candidate is not performed.

<Historical predicted motion vector candidate list>
Here, the structure and operation of the history predicted motion vector candidate list will be explained.

As shown in FIG. 68, the inter prediction information used by inter prediction in the current block to be encoded is set as the inter prediction information candidate hMvpCand to be registered, and the historical predicted motion vector candidate list HmvpCandList is used as the history that has been used in the past. Register. In FIG. 68, the history predicted motion vector candidate list has a list structure that can store six elements, and is a FIFO (First-In, First Out) method in which the elements stored first are retrieved in order. is the basic storage operation.

Here, as an example, the maximum number of elements that can be stored in HmvpCandList will be explained as six, as agreed upon between the encoding side and the decoding side, but this is not particularly limited and the maximum number of elements that can be stored in HmvpCandList may be six or more. Further, the maximum number of elements that can be stored in HmvpCandList may be five, or a smaller number of elements may be configured. For example, HmvpCandList may be configured to have a maximum number of elements equivalent to the maximum number of elements of inter prediction information candidates, such as the maximum number of elements, the maximum number of merging candidates, and the maximum number of subblock merging candidates of the motion vector predictor list mvpListLX. Furthermore, HmvpCandList may be configured to be linked to the maximum number of elements of inter prediction information candidates for each mode.

By including the maximum number of elements of this HmvpCandList in the syntax element of the encoded bitstream, it may be configured to be transmitted from the encoding side to the decoding side.

As shown in FIG. 68, HmvpCandList can store six elements from position 0 at the beginning of the list to position 5 at the end of the list, and can fill elements from position 0 to position 5. This position 0 to position 5 is managed as a historical predicted motion vector index hMvpIdx. For example, position 0 can be expressed as hMVpIdx[0], and position 5 can be expressed as hMVpIdx[5]. The number of stored elements of HmvpCandList is managed by NumHmvpCand, and the increase or decrease of the stored elements is managed in the range from 0 to 6, which is the maximum number of elements.

The case where a new element is added from the end with the maximum number of elements stored in HmvpCandList will be explained. As shown in FIG. 69, when attempting to newly register inter prediction information candidate hMvpCand as a history, the element at position 0, which is the head, is deleted, and the position of each element is shifted one by one toward the head. As a result of the shift, the number of stored elements decreases by one as shown in FIG. 70, so that a new element can be stored at position 5 at the end. Therefore, by storing the inter prediction information candidate hMvpCand in position 5 at the end, a new element is added to HmvpCandList as shown in FIG. 71.

(Modification example 1)
As a modification of the first embodiment, the following processing is performed on the history predicted motion vector candidate list.
<Searching for identical candidates in the history predicted motion vector candidate list>
When using the history predicted motion vector candidate list HmvpCandList in the reference order as shown in FIG. 72, the inter prediction information candidate hMvpCand to be registered is If inter prediction with the same value exists, that element (inter prediction information) is deleted from the historical predicted motion vector candidate list HmvpCandList. Hereinafter, such same candidate deletion processing will be referred to as same candidate deletion processing.
When adding an element to the history predicted motion vector candidate list HmvpCandList, the same candidate deletion process is not performed. Furthermore, when using the historical predicted motion vector candidate list HmvpCandList while referring to it in the reverse order of the storage order in which new elements are added to the end of the historical predicted motion vector candidate list as shown in FIG. Configure so that the same candidate deletion process is not performed.
In FIG. 65, the motion information that is the historical predicted motion vector candidate stored in the historical predicted motion vector candidate list HmvpCandList is referenced in the reverse order of the storage order starting from the end, starting from the oldest motion information. , is a flowchart illustrating a procedure for deriving historical predicted motion vector candidates in a case where newly added motion information is referred to and used in order and the same candidate deletion process is not performed.
The inter prediction information used when performing inter prediction in the normal prediction vector mode or the normal merge mode is set as the inter prediction information candidate hMvpCand to be registered, and the coding information storage memory 111 on the coding side and the coding information storage memory on the decoding side Regardless of whether there is an inter prediction with the same value as the inter prediction information candidate hMvpCand to be registered among the inter prediction information registered in the history predicted motion vector candidate list HmvpCandList prepared for 205, the most Inter prediction information candidates hMvpCand to be registered are added in order from the closest vacant position. If HmvpCandList is filled to the maximum number of elements, the first element (inter prediction information) of the history predicted motion vector candidate list HmvpCandList is deleted, and the inter prediction information to be registered is added to the end of the history prediction motion vector candidate list HmvpCandList. Add candidate hMvpCand.
In this embodiment, the number of elements of the historical predicted motion vector candidate list HmvpCandList provided in the encoded information storage memory 111 on the encoder side and the encoded information storage memory 205 on the decoder side is assumed to be six. First, perform initial settings for each slice. The history predicted motion vector candidate list HmvpCandList is initialized at the beginning of the slice, and the value of the number of history predicted motion vector candidates NumHmvpCand registered in the history prediction motion vector candidate list HmvpCandList is set to 0 (step S2401 in FIG. 65). .
Subsequently, the following process of updating the history predicted motion vector candidate list HmvpCandList is repeatedly performed for each encoded block within the slice (steps S2402 to S2407 in FIG. 65).
It is determined whether the inter prediction information candidate hMvpCand to be registered exists in the historical predicted motion vector candidate list HmvpCandList (step S2404 in FIG. 65). If the prediction method determining unit 105 on the encoding side determines that the mode is the normal predicted motion vector mode or the normal merge mode, or if the bit string decoding unit on the decoding side decodes as the normal predicted motion vector mode or the normal merge mode, the inter Set the prediction mode to hMvpCand. If the prediction method determination unit 105 on the encoding side determines to be intra prediction mode, sub-block predicted motion vector mode, or sub-block merge mode, or the bit string decoding unit on the decoding side determines intra prediction mode, sub-block predicted motion vector mode, or When decoding is performed in sub-block merge mode, the history predicted motion vector candidate list HmvpCandList is not updated, and there is no inter prediction information candidate hMvpCand to be registered. If the inter prediction information candidate hMvpCand to be registered does not exist, step S2406 is skipped (step S2404 in FIG. 65: NO). If there is an inter prediction information candidate hMvpCand to be registered, the processes from step S2406 onwards are performed (step S2404 in FIG. 65: YES).
Next, the elements of the history predicted motion vector candidate list HmvpCandList are shifted and added (step S2406 in FIG. 65).
By performing the processing shown in FIG. 65, it is possible to omit the same candidate checking and deletion processing, the setting of variables for executing the processing, and the comparison processing, and it is possible to reduce the amount of processing.
In addition, when adding elements to the historical predicted motion vector candidate list HmvpCandList, even if the same candidate deletion process is not performed on the historical predicted motion vector candidate list, the newly added motion information will be changed from the old motion information. By being able to refer to the motion vector predictors in order, it is possible to reduce the possibility that the same candidate will be added to the motion vector predictor candidate list.

(Modification example 2)
As a modification of the first embodiment, the element shift/addition processing procedure of the history predicted motion vector candidate list HmvpCandList in step S2406 in FIG. 65 is configured as follows.
FIG. 66 is a flowchart of the element shift/addition processing procedure for the history predicted motion vector candidate list HmvpCandList in step S2406 of FIG. 65.
First, it is determined whether to add a new element after removing the first element stored in the history predicted motion vector candidate list HmvpCandList, or to add a new element without removing the element. Specifically, it is compared whether NumHmvpCand is 6 (step S2541 in FIG. 66). If NumHmvpCand is 6 (step S2541 in FIG. 66: YES), a new element is added after removing the first element stored in the history predicted motion vector candidate list HmvpCandList. Set the initial value of index i to the value 1. The element shift process of step S2543 is repeated from this initial value to NumHmvpCand. (Steps S2542 to S2544 in FIG. 66). The elements of HmvpCandList [i] are copied to HmvpCandList [i - 1] to shift the elements forward (step S2543 in FIG. 66), and i is incremented by 1 (steps S2542 and S2544 in FIG. 66). Next, the inter prediction information candidate hMvpCand is added to the (NumHmvpCand-1)th HmvpCandList [NumHmvpCand-1] counting from 0, which corresponds to the end of the history prediction motion vector candidate list (step S2545 in FIG. 66), and the actual history prediction is performed. The element shift/addition process for the motion vector candidate list HmvpCandList ends. On the other hand, if NumHmvpCand is not 6 (step S2541 in FIG. 66: NO), a new element is added without removing the elements stored in the history predicted motion vector candidate list HmvpCandList. The inter prediction information candidate hMvpCand is added to the (NumHmvpCand-1)th HmvpCandList [NumHmvpCand], counting from 0 corresponding to the end of the history predicted motion vector candidate list, NumHmvpCand is incremented by 1 (step S2546 in FIG. 66), and the main The element shift/addition process for the history predicted motion vector candidate list HmvpCandList is completed.
By performing the processing shown in FIG. 66, it is possible to omit the same candidate checking and deletion processing, the setting of variables for executing the processing, and the comparison processing, and it is possible to reduce the amount of processing.

(Modification example 3)
In this embodiment, the history predicted motion vector candidate list HmvpCandList is used while referring to the storage order in which new motion information is added from the tail side, and the motion that is the history predicted motion vector candidate stored in HmvpCandList is A case is described in which the information is sequentially referenced and used from the oldest motion information to the newly added motion information, but the same candidate deletion process is not performed.
In a modification of the first embodiment, there is a forward order mode in which older motion information is referenced from newly added motion information in the same direction as the storage order in which the reference order is added from the end; A reverse order mode is provided in which newly added motion information is referenced from old motion information in the opposite direction to the storage order in which new motion information is added from the side, and the reference order of the historical predicted motion vector candidate list HmvpCandList is switched. The configuration is configured so that the forward order mode and the reverse order mode can be switched by using the history reference flag information. This history reference flag is included in the syntax element of the encoded bitstream and transmitted to the decoding side, and the decoding side acquires the encoded bitstream having this history reference flag in the syntax element so that it can be decoded.

(Second embodiment)
As a second embodiment, when deriving the motion vector predictor candidate list mvpListLX, the configuration is as follows. In particular, when deriving the motion vector predictor candidate list mvpListLX, the historical motion vector predictor candidate list HmvpCandList is used while referring from the beginning in the reverse order of the storage order newly added from the end. In the process of adding a motion vector predictor candidate to the motion vector predictor candidate list, the configuration is such that the process of determining whether the same motion vector predictor is included in the motion vector predictor candidate list is not performed.

The history predicted motion vector candidate derivation process of this embodiment will be described below.

<Historic predicted motion vector candidate derivation process without identical candidate deletion process>
Here, a history predicted motion vector candidate derivation process that does not involve the same candidate deletion process will be described.

FIG. 74 shows a case in which when deriving the motion vector predictor candidate list mvpListLX, the historical motion vector predictor candidate list HmvpCandList is referenced in the reverse order of the storage order, and the same candidate deletion process is not performed. 12 is a flowchart illustrating a procedure for deriving historical predicted motion vector candidates.

If the current number of motion vector predictor candidates numCurrMvpCand is greater than or equal to the maximum number of elements (here, 2) of the motion vector predictor list mvpListLX, or if the number of historical motion vector predictor candidates is 0 (step S2601 in FIG. 74): NO), the processes from steps S2602 to S2609 in FIG. 41 are omitted, and the history predicted motion vector candidate derivation process procedure is ended. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2601 in FIG. 74: YES), steps S2602 to S2609 in FIG. 74 are performed.

Subsequently, the processes of steps S2603 to S2608 in FIG. 74 are repeated until the index i is from 0 to 4 or the number of historical predicted motion vector candidates, NumHmvpCand, whichever is smaller - 1 (steps S2602 to S2609 in FIG. 74). If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2603 in FIG. 74: NO), the processes from steps S2604 to S2609 in FIG. 74 are omitted, and this history The motion vector predictor candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor list mvpListLX (step S2603 in FIG. 74: YES), the process from step S2604 in FIG. 74 is performed.

Subsequently, the processes from steps S2605 to S2607 are performed for indexes Y of 0 and 1 (L0 and L1), respectively (steps S2604 to S2608 in FIG. 74). If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2605 in FIG. 74: NO), the processes from steps S2606 to S2609 in FIG. 74 are omitted, and this history The motion vector predictor candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor list mvpListLX (step S2605 in FIG. 74: YES), the processes from step S2606 in FIG. 74 are performed.

Next, if the reference index of LY in the historical predicted motion vector candidate list HmvpCandList[i] is an element of the same reference index as the reference index refIdxLX of the motion vector to be encoded/decoded (step S2606 in FIG. 74: YES), The motion vector of LY of the historical motion vector predictor candidate HmvpCandList[i] is added to the numCurrMvpCand-th element mvpListLX[numCurrMvpCand] counting from 0 in the motion vector predictor candidate list (step S2607 in FIG. 74), and the current motion vector predictor candidate is added. Increment the number numCurrMvpCand by 1. If the reference index of LY in the historical predicted motion vector candidate list HmvpCandList[i] is not an element with the same reference index as the reference index refIdxLX of the motion vector to be encoded/decoded (step S2606 in FIG. 74: NO), add step S2607. Skip processing.

The above processing from steps S2605 to S2607 in FIG. 74 is performed on both L0 and L1 (steps S2604 to S2608 in FIG. 74).

The index i is incremented by 1 (steps S2602 and S2609 in FIG. 74), and if the index i is less than or equal to the smaller value of 4 or the number of history predicted motion vector candidates NumHmvpCand, the process from step S2603 onwards is performed again (see FIG. 74 steps S2602 to S2609).
By performing the historical motion vector predictor candidate derivation process as described above, the same candidate deletion process is not involved in the process of adding from the historical motion vector predictor candidate list to the motion vector predictor candidate list. Checking and deleting processing, variable setting and comparison processing for executing the processing can be omitted, and the amount of processing can be reduced.
In addition, by making it possible to refer to the motion information that is a historical predicted motion vector candidate stored in HmvpCandList in order from the oldest motion information to the newly added motion information, various motion information can be added to the predicted motion vector candidate list. It becomes possible to add to.
Furthermore, in the process of adding motion vector predictor candidates from the historical motion vector predictor candidate list to the motion vector predictor candidate list, even if the same candidate deletion process is not performed on the historical motion vector predictor candidate list, the newly added motion vectors will be added from the oldest motion vector candidate list. By making it possible to refer to the motion information in order, it is possible to reduce the possibility that the same candidate will be added to the motion vector predictor candidate list.

(Modification example 1)
In the second embodiment, when deriving the motion vector predictor candidate list mvpListLX, the historical motion vector predictor candidate list HmvpCandList is used while being referenced from the beginning in the reverse order of the storage order that is newly added from the end, A case is described in which the same candidate deletion process is not performed.
In the modified example of the second embodiment, as shown below, only the reference order of the history predicted motion vector candidate list HmvpCandList is referenced from the beginning in the reverse order of the storage order in which newly added from the end, The configuration is such that the newly added motion information is referred to from the old motion information, and the identical candidate deletion process is performed as is.

FIG. 75 explains the procedure for deriving historical predicted motion vector candidates when the historical predicted motion vector candidate list HmvpCandList is used while being referenced in the reverse order of the storage order, and the same candidate deletion process is not performed. This is a flowchart.

If the current number of motion vector predictor candidates, numCurrMvpCand, is greater than or equal to the maximum number of elements (here, 2) of the motion vector predictor list mvpListLX, or if the number of historical motion vector predictor candidates is 0, the value of NumHmvpCand is 0 (step S2801 in FIG. 75: NO), steps S2802 to S2809 in FIG. 41 are omitted, and the history predicted motion vector candidate derivation processing procedure is ended. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor list mvpListLX (step S2801 in FIG. 75: YES), steps S2802 to S2809 in FIG. 75 are performed.

Subsequently, the processes of steps S2803 to S2808 in FIG. 75 are repeated until the index i is from 0 to 4 or the number of historical predicted motion vector candidates, NumHmvpCand, whichever is smaller - 1 (steps S2802 to S2809 in FIG. 75). If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2803 in FIG. 75: NO), the processes from steps S2804 to S2809 in FIG. 75 are omitted, and this history The motion vector predictor candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2803 in FIG. 75: YES), the processes from step S2804 in FIG. 75 are performed.

Subsequently, the processes from steps S2805 to S2807 are performed for indexes Y of 0 and 1 (L0 and L1), respectively (steps S2804 to S2808 in FIG. 75). If the current number of motion vector predictor candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the motion vector predictor list mvpListLX (step S2805 in FIG. 75: NO), the processes from steps S2806 to S2809 in FIG. 75 are omitted, and this history The motion vector predictor candidate derivation processing procedure ends. If the current number of motion vector predictor candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements in the motion vector predictor list mvpListLX (step S2805 in FIG. 75: YES), the processes from step S2806 in FIG. 75 are performed.

Next, the reference index of LY in the historical motion vector predictor candidate list HmvpCandList[i] is an element with the same reference index as the reference index refIdxLX of the motion vector to be encoded/decoded, and is different from any element in the motion vector predictor list mvpListLX. If there is an element (step S2806 in FIG. 75: YES), add the LY motion vector of the historical motion vector predictor candidate HmvpCandList[i] to the numCurrMvpCand-th element mvpListLX[numCurrMvpCand] counting from 0 in the motion vector predictor candidate list. (Step S2807 in FIG. 75), the current number of motion vector predictor candidates numCurrMvpCand is incremented by one. The reference index of LY in the historical motion vector predictor candidate list HmvpCandList[i] is an element with the same reference index as the reference index refIdxLX of the motion vector to be encoded/decoded, and there is no element that is different from any element in the motion vector predictor list mvpListLX. (Step S2806 in FIG. 75: NO), the additional processing in Step S2807 is skipped.

The above processing from steps S2805 to S2807 in FIG. 75 is performed in both L0 and L1 (steps S2804 to S2808 in FIG. 75).

The index i is incremented by 1, and if the index i is less than the smaller value of 4 or the number of history predicted motion vector candidates NumHmvpCand - 1, the process from step S2803 onwards is performed again (steps S2802 to S2809 in FIG. 75).
By performing the history predicted motion vector candidate derivation process as described above, the same candidate deletion process is performed as is, and the motion information that is the history predicted motion vector candidate stored in HmvpCandList is changed from the old motion information to the new one. By making it possible to refer to the added motion information in order, it becomes possible to add more diverse motion information to the predicted motion vector candidate list.

(Modification example 2)
As a modification of the second embodiment, when deriving the motion vector predictor candidate list mvpListLX, the element shift/addition processing procedure of the historical motion vector predictor candidate list HmvpCandList in step S2406 of FIG. 65 is changed as shown in FIG. Configure. Description of FIG. 66 is omitted because it is the same as described above.
By performing the processing shown in FIG. 66, it is possible to omit the same candidate checking and deletion processing, the setting of variables for executing the processing, and the comparison processing, and it is possible to reduce the amount of processing.

(Modification example 3)
In the second embodiment, when deriving the motion vector predictor candidate list mvpListLX, the historical motion vector predictor candidate list HmvpCandList is used while referring to it in the reverse order of the storage order in which new motion information is added from the tail side. , when the motion information that is the historical predicted motion vector candidate stored in HmvpCandList is used while referring to the newly added motion information in order from the oldest motion information, and the same candidate deletion process is not performed. is explained.
In a modification of the second embodiment, there is a forward order mode in which older motion information is referenced from newly added motion information in the same direction as the storage order in which the reference order is added from the end; A reverse order mode is provided in which newly added motion information is referenced from old motion information in the opposite direction to the storage order in which new motion information is added from the side, and the reference order of the historical predicted motion vector candidate list HmvpCandList is switched. The configuration is configured so that the forward order mode and the reverse order mode can be switched by using the history reference flag information. This history reference flag is included in the syntax element of the encoded bitstream and transmitted to the decoding side, and the decoding side acquires the encoded bitstream having this history reference flag in the syntax element so that it can be decoded.

(Third embodiment)
As a third embodiment, when deriving a merging candidate list, the configuration is as follows. In particular, the reference order when using the historical predicted motion vector candidate list is changed so that the oldest motion information is referred to and the newly added motion information is sequentially used. Furthermore, when adding a new element to the merge candidate list, the process of searching for and deleting an element with the same information from the history predicted motion vector candidate list is changed so that it is not performed. Furthermore, in the normal merge mode, when deriving normal merging candidates using the historical predicted motion vector candidate list HmvpCandList, elements with the same information are searched from the historical predicted motion vector candidate list, and elements with the same information are searched for from the historical predicted motion vector candidate list. Change it so that it does not perform the processing that normally does not make it a merge candidate.
<History merging candidate derivation process without identical candidate deletion process>
Here, history merging candidate derivation processing that does not involve identical candidate deletion processing will be described.
FIG. 67 shows history merging candidate derivation in a case where the history predicted motion vector candidate list HmvpCandList is used while sequentially referring from old motion information to newly added motion information, and the same candidate deletion process is not performed. It is a flowchart explaining a processing procedure.
First, initialization processing is performed (step S2701 in FIG. 67). Set the number of elements registered in the current merge candidate list numCurrMergeCand to the variable numOrigMergeCand.
The initial value of the index hMvpIdx is set to 0, and the additional processing from step S2703 to step S2710 in FIG. 67 is repeated from this initial value to NumHmvpCand-1 (steps S2702 to S2711 in FIG. 67). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, and this history merge candidate is derived. The process ends (step S2703 in FIG. 67: NO). If the number numCurrMergeCand of elements registered in the current merge candidate list is less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), processing from step S2710 onwards is performed. (Step S2703 in FIG. 67: YES). The hMvpIdx-th element HmvpCandList[hMvpIdx] of the history predicted motion vector candidate list is added to the numCurrMergeCand-th mergeCandList[numCurrMergeCand] of the merge candidate list, and numCurrMergeCand is incremented by 1 (step S2710 in FIG. 67). The index hMvpIdx is incremented by 1 (step S2702 in FIG. 67), and steps S2702 to S2711 in FIG. 67 are repeated.
When confirmation of all the elements in the history predicted motion vector candidate list is completed, or when merging candidates are added to all the elements in the merging candidate list, this history merging candidate derivation process is completed.
By performing the history merging candidate derivation process as described above, the same candidate deletion process is not involved in the process of adding from the history predicted motion vector candidate list to the merging candidate list, and the same candidate checking and deletion process is performed. It is possible to omit setting of variables and comparison processing for executing the processing, and it becomes possible to reduce the amount of processing.
In addition, by making it possible to refer to the motion information that is a historical predicted motion vector candidate stored in HmvpCandList in order from the oldest motion information to the newly added motion information, a variety of motion information can be added to the merge candidate list. It becomes possible to do so.
Furthermore, in the process of adding from the historical predicted motion vector candidate list to the merge candidate list, even if the same candidate deletion process is not performed on the historical predicted motion vector candidate list, newly added motion information is By allowing information to be referred to in order, it is possible to reduce the possibility that the same candidate will be added to the merging candidate list.

(Modification example 1)
As a modification of the third embodiment, when deriving a merge candidate list, when adding an element to the history predicted motion vector candidate list HmvpCandList as shown in FIG. Configure. The explanation of FIG. 65 is omitted because it is the same as above.
By performing the processing shown in FIG. 65, it is possible to omit the same candidate checking and deletion processing, the setting of variables for executing the processing, and the comparison processing, and it is possible to reduce the amount of processing.
In addition, when adding elements to the historical predicted motion vector candidate list HmvpCandList, even if the same candidate deletion process is not performed on the historical predicted motion vector candidate list, the newly added motion information will be changed from the old motion information. By making it possible to refer to the items in order, it is possible to reduce the possibility that the same candidate will be added to the merging candidate list.

(Modification example 2)
As a modification of the third embodiment, when deriving a merge candidate list, the element shift/addition processing procedure of the history predicted motion vector candidate list HmvpCandList in step S2406 of FIG. 65 is configured as shown in FIG. 66. . The explanation of FIG. 66 is omitted because it is the same as above.
By performing the processing shown in FIG. 66, it is possible to omit the same candidate checking and deletion processing, the setting of variables for executing the processing, and the comparison processing, and it is possible to reduce the amount of processing.

(Modification example 3)
In the third embodiment, when deriving a merge candidate list, the motion information that is the history predicted motion vector candidate stored in HmvpCandList is sequentially referred to from the oldest motion information to the newly added motion information. This section describes a case where the configuration is configured so that the same candidate deletion process is not performed.
In a modification of the third embodiment, a normal mode in which the reference order refers to the older motion information from the newly added motion information, and a forward order mode in which the older motion information is referenced in the reference order to the newly added motion information. A reverse order mode is prepared, and the configuration is configured such that the forward order mode and the reverse order mode can be switched using history reference flag information for switching the reference order of the history predicted motion vector candidate list HmvpCandList. This history reference flag is included in the syntax element of the encoded bitstream and transmitted to the decoding side, and the decoding side acquires the encoded bitstream having this history reference flag in the syntax element so that it can be decoded.

All of the embodiments described above may be combined.

In all the embodiments described above, the encoded bitstream output by the image encoding device has a specific data format so that it can be decoded according to the encoding method used in the embodiment. are doing. The encoded bitstream may be provided by being recorded on a computer-readable recording medium such as an HDD, SSD, flash memory, or optical disk, or may be provided from a server through a wired or wireless network. Therefore, an image decoding device corresponding to this image encoding device can decode the encoded bitstream of this specific data format, regardless of the providing means.

When a wired or wireless network is used to exchange encoded bitstreams between an image encoding device and an image decoding device, the encoded bitstreams are converted into a data format suitable for the transmission form of the communication channel. May be transmitted. In that case, there is a transmitting device that converts the encoded bitstream output by the image encoding device into encoded data in a data format suitable for the transmission form of the communication channel and sends it to the network, and a transmitter that receives the encoded data from the network. A receiving device is provided that restores the encoded bitstream and supplies the encoded bitstream to an image decoding device. The transmitting device includes a memory that buffers the encoded bitstream output by the image encoding device, a packet processing unit that packetizes the encoded bitstream, and a transmitting unit that transmits the packetized encoded data via a network. including. The receiving device includes a receiving unit that receives packetized encoded data via a network, a memory that buffers the received encoded data, and performs packet processing on the encoded data to generate an encoded bitstream. and a packet processing unit provided to the image decoding device.

When a wired or wireless network is used to exchange encoded bitstreams between an image encoding device and an image decoding device, in addition to the transmitting device and the receiving device, the encoded data transmitted by the transmitting device is A relay device may be provided for receiving and supplying the signal to the receiving device. The relay device includes a receiving unit that receives the packetized encoded data transmitted by the transmitting device, a memory that buffers the received encoded data, and a transmitting unit that transmits the packetized encoded data to the network. include. Furthermore, the relay device includes a reception packet processing unit that performs packet processing on the packetized encoded data to generate an encoded bitstream, a recording medium that stores the encoded bitstream, and a recording medium that packetizes the encoded bitstream. It may also include a transmission packet processing section.

Further, by adding a display section that displays images decoded by an image decoding device to the configuration, it may be used as a display device. In that case, the display section reads out the decoded image signal generated by the decoded image signal superimposing section 207 and stored in the decoded image memory 208 and displays it on the screen.

Alternatively, an imaging device may be used by adding an imaging section to the configuration and inputting the captured image to an image encoding device. In that case, the imaging unit inputs the captured image signal to the block dividing unit 101.

Of course, the above encoding and decoding processes can be realized as a transmission, storage, and reception device using hardware, or can be stored in a ROM (read-only memory), flash memory, etc. It may be realized by firmware or software of a computer or the like. The firmware program and software program may be provided by being recorded on a computer-readable recording medium, or may be provided from a server through a wired or wireless network, or may be provided through data broadcasting of terrestrial or satellite digital broadcasting. It may be provided as

The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that the embodiments are merely illustrative, and that various modifications can be made to the combinations of the constituent elements and processing processes, and that such modifications are also within the scope of the present invention. .

100 image encoding device, 101 block division unit, 102 inter prediction unit, 103 intra prediction unit, 104 decoded image memory, 105 prediction method determination unit, 106 residual signal generation unit, 107 orthogonal transformation/quantization unit, 108 bit string code 109 inverse quantization/inverse orthogonal transform unit, 110 decoded image signal superimposition unit, 111 encoded information storage memory, 200 image decoding device, 201 bit string decoding unit, 202 block division unit, 203 inter prediction unit 204 intra prediction unit , 205 encoded information storage memory, 206 inverse quantization/inverse orthogonal transform unit, 207 decoded image signal superimposition unit, 208 decoded image memory.

Claims (8)

a bit string encoding unit that encodes encoding information indicating whether the block to be encoded is encoded in the normal merge mode or in the sub-block merge mode;
a subblock merge mode deriving unit that encodes the encoding target block in the subblock merge mode when the encoding information indicates a subblock merge mode;
a normal merge mode deriving unit that encodes the encoding target block in the normal merge mode when the encoding information indicates the normal merge mode;
Further, the normal merge mode deriving unit
a history prediction candidate list update unit that adds motion information of the encoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving unit that derives a spatial motion information candidate from motion information of a block spatially adjacent to the encoding target block, and adds the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving unit that derives a temporal motion information candidate from motion information of a block temporally close to the encoding target block, and adds the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate derivation unit that derives historical motion information candidates from the historical predicted motion vector candidate list and adds them to the predicted motion vector candidate list;
Equipped with
The historical motion information candidate derivation unit derives the historical motion information candidates by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A moving image encoding device characterized by: a bit string encoding step of encoding encoding information indicating whether the block to be encoded is encoded in normal merge mode or subblock merge mode;
When the encoding information indicates a subblock merging mode, a subblock merging mode deriving step of encoding the encoding target block in the subblock merging mode;
If the encoding information indicates a normal merge mode, a normal merge mode deriving step of encoding the encoding target block in a normal merge mode;
has
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the encoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from motion information of a block spatially adjacent to the encoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the encoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate deriving step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list;
has
In the step of deriving historical motion information candidates, the historical motion information candidates are derived by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A video encoding method characterized by: to the computer,
a bit string encoding step of encoding encoding information indicating whether the block to be encoded is encoded in normal merge mode or subblock merge mode;
When the encoding information indicates a subblock merging mode, a subblock merging mode deriving step of encoding the encoding target block in the subblock merging mode;
If the encoding information indicates a normal merge mode, a normal merge mode deriving step of encoding the encoding target block in a normal merge mode;
A video encoding program for executing
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the encoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from motion information of a block spatially adjacent to the encoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the encoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate deriving step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list;
has
In the step of deriving historical motion information candidates, the historical motion information candidates are derived by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A video encoding program characterized by: a bit string decoding unit that decodes decoding information indicating whether the block to be decoded is decoded in normal merge mode or subblock merge mode;
When the decoding information indicates a sub-block merging mode, a sub-block merging mode deriving unit that decodes the block to be decoded in the sub-block merging mode;
a normal merge mode deriving unit that decodes the block to be decoded in the normal merge mode when the decoding information indicates the normal merge mode;
Further, the normal merge mode deriving unit
a history prediction candidate list update unit that adds motion information of the decoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving unit that derives a spatial motion information candidate from motion information of a block spatially adjacent to the decoding target block, and adds the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving unit that derives a temporal motion information candidate from motion information of a block temporally close to the decoding target block, and adds the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate derivation unit that derives historical motion information candidates from the historical predicted motion vector candidate list and adds them to the predicted motion vector candidate list;
Equipped with
The historical motion information candidate derivation unit derives the historical motion information candidates by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A moving image decoding device characterized by: a bit string decoding step of decoding decoding information indicating whether the block to be decoded is to be decoded in normal merge mode or sub-block merge mode;
When the decoding information indicates a sub-block merging mode, a sub-block merging mode deriving step of decoding the decoding target block in the sub-block merging mode;
If the decoding information indicates a normal merge mode, a normal merge mode deriving step of decoding the block to be decoded in a normal merge mode,
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the decoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from the motion information of a block spatially adjacent to the decoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the decoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate deriving step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list;
has
In the step of deriving historical motion information candidates, the historical motion information candidates are derived by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A moving image decoding method characterized by: to the computer,
a bit string decoding step of decoding decoding information indicating whether the block to be decoded is to be decoded in normal merge mode or sub-block merge mode;
When the decoding information indicates a sub-block merging mode, a sub-block merging mode deriving step of decoding the decoding target block in the sub-block merging mode;
When the decoding information indicates a normal merge mode, a normal merge mode deriving step of decoding the block to be decoded in the normal merge mode;
A video decoding program for executing
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the decoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from the motion information of a block spatially adjacent to the decoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the decoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
a historical motion information candidate deriving step of deriving historical motion information candidates from the historical predicted motion vector candidate list and adding them to the predicted motion vector candidate list;
has
In the step of deriving historical motion information candidates, the historical motion information candidates are derived by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing motion information with elements of the predicted motion vector candidate list, adding to the motion vector predictor candidate list;
A moving image decoding program characterized by the following. A storage method for storing a bitstream encoded using historical motion information candidates, the method comprising:
a bit string encoding step of encoding encoding information indicating whether the block to be encoded is encoded in normal merge mode or subblock merge mode;
When the encoding information indicates a subblock merging mode, a subblock merging mode deriving step of encoding the encoding target block in the subblock merging mode;
If the encoding information indicates a normal merge mode, a normal merge mode deriving step of encoding the encoding target block in the normal merge mode,
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the encoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from motion information of a block spatially adjacent to the encoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the encoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
Deriving the historical motion information candidates from the historical predicted motion vector candidate list by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing the motion information with elements of the historical predicted motion vector candidate list. historical motion information candidate derivation step;
A bitstream storage method comprising: A transmission method for transmitting a bitstream encoded using historical motion information candidates, the method comprising:
a bit string encoding step of encoding encoding information indicating whether the block to be encoded is encoded in normal merge mode or subblock merge mode;
When the encoding information indicates a subblock merging mode, a subblock merging mode deriving step of encoding the encoding target block in the subblock merging mode;
If the encoding information indicates a normal merge mode, a normal merge mode deriving step of encoding the encoding target block in the normal merge mode,
Further, the normal merge mode deriving step includes:
a history prediction candidate list update step of adding motion information of the encoded block to the end of the history prediction motion vector candidate list;
a spatial motion information candidate deriving step of deriving a spatial motion information candidate from motion information of a block spatially adjacent to the encoding target block, and adding the spatial motion information candidate to a predicted motion vector candidate list;
a temporal motion information candidate deriving step of deriving a temporal motion information candidate from motion information of a block temporally close to the encoding target block, and adding the temporal motion information candidate to the predicted motion vector candidate list;
Deriving the historical motion information candidates from the historical predicted motion vector candidate list by sequentially referring to the historical predicted motion vector candidate list from the beginning without comparing the motion information with elements of the historical predicted motion vector candidate list. historical motion information candidate derivation step;
A bitstream transmission method characterized by comprising:.

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