JP2013090032A - Video image coding device, video image coding method, and video image coding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an optimal reference picture is not necessarily used in a time direct mode.SOLUTION: A reference index deriving part 131 of a time merge candidate derives reference index information which identifies a reference picture used in a prediction block to be coded as reference index information of the time merge candidate. A time merge candidate generating part 132 derives inter-prediction information of the time merge candidate on the basis of the derived reference index information. The reference index deriving part 131 sets a smaller value out of the reference index information in the prediction block which adjoins the left side of the prediction block to be coded and the reference index information in the prediction block which adjoins the upper side of the prediction block to be coded, to the reference index of the time merge candidate.

Description

  The present invention relates to a moving picture coding technique, and more particularly to a moving picture coding technique using motion compensated prediction.

  As a typical moving image compression encoding method, MPEG-4 AVC / H. There are H.264 standards. MPEG-4 AVC / H. In H.264, motion compensation is used in which a picture is divided into a plurality of rectangular blocks, a picture that has already been encoded / decoded is used as a reference picture, and motion from the reference picture is predicted. This method of predicting motion by motion compensation is called inter prediction or motion compensated prediction. MPEG-4 AVC / H. In the inter prediction in H.264, a plurality of pictures can be used as reference pictures, and the most suitable reference picture is selected for each block from the plurality of reference pictures to perform motion compensation. Therefore, a reference index is assigned to each reference picture, and the reference picture is specified by this reference index. Note that, for B pictures, a maximum of two reference pictures that have been encoded and decoded can be selected and used for inter prediction. The predictions from these two reference pictures are distinguished as L0 prediction (list 0 prediction) mainly used as forward prediction and L1 prediction (list 1 prediction) mainly used as backward prediction.

  Furthermore, bi-prediction using two inter predictions of L0 prediction and L1 prediction at the same time is also defined. In the case of bi-prediction, bi-directional prediction is performed, the inter-predicted signals of L0 prediction and L1 prediction are multiplied by a weighting coefficient, an offset value is added and superimposed, and a final inter-predicted image signal is obtained. Generate. As weighting coefficients and offset values used for weighted prediction, representative values are set for each reference picture in each list and encoded. The encoding information related to inter prediction includes, for each block, a prediction mode for distinguishing between L0 prediction and L1 prediction and bi-prediction, a reference index for specifying a reference picture for each reference list for each block, and a moving direction and a moving amount of the block. There is a motion vector that expresses and encodes and decodes the encoded information.

  Furthermore, MPEG-4 AVC / H. H.264 defines a direct mode for generating inter prediction information of a block to be encoded / decoded from inter prediction information of an encoded / decoded block. In the direct mode, encoding of inter prediction information is not necessary, so that encoding efficiency is improved.

  A temporal direct mode using the correlation of inter prediction information in the time direction will be described with reference to FIG. A picture in which the reference index of L1 is registered as 0 is defined as a reference picture colPic. A block in the same position as the encoding / decoding target block in the reference picture colPic is set as a reference block.

  If the reference block is encoded using the L0 prediction, the L0 motion vector of the reference block is set as the reference motion vector mvCol, and the reference block is not encoded using the L0 prediction and is encoded using the L1 prediction. If this is the case, the L1 motion vector of the reference block is set as the reference motion vector mvCol. The picture referred to by the reference motion vector mvCol is the L0 reference picture in the temporal direct mode, and the reference picture colPic is the L1 reference picture in the temporal direct mode.

  From the reference motion vector mvCol, the L0 motion vector mvL0 and the L1 motion vector mvL1 in the temporal direct mode are derived by scaling calculation processing.

The inter-picture distance td is derived by subtracting the POC of the L0 reference picture in the temporal direct mode from the POC of the base picture colPic. Note that POC is a variable associated with a picture to be encoded, and is set to a value that increases by 1 in the picture output / display order. The difference in POC between two pictures indicates the inter-picture distance in the time axis direction.
td = POC of base picture colPic-POC of L0 reference picture in temporal direct mode

The inter-picture distance tb is derived by subtracting the POC of the L0 reference picture in the temporal direct mode from the POC of the picture to be encoded / decoded.
tb = POC of picture to be encoded / decoded-POC of L0 reference picture in temporal direct mode

The motion vector mvL0 of L0 in the temporal direct mode is derived from the reference motion vector mvCol by scaling calculation processing.
mvL0 = tb / td * mvCol

The motion vector mvL1 of L1 is derived by subtracting the reference motion vector mvCol from the motion vector mvL0 of L0 in the temporal direct mode.
mvL1 = mvL0-mvCol

JP 2004-129191 A

  However, in the conventional method, it is difficult to say that a temporally direct reference picture can be used for an encoding / decoding target block, and encoding efficiency may not be improved. More specifically, in the above-described temporal direct mode, the reference picture of L0 in the temporal direct mode becomes the reference picture of L0 of the base block of the base picture different from the picture to be encoded / decoded. Since the reference picture is a picture fixedly registered with the reference index of L1 being 0, an optimal reference picture is not always obtained.

  Under such circumstances, the present inventors have come to recognize the necessity of further compressing the encoded information and reducing the overall code amount in the moving image encoding method using motion compensation prediction.

  The present invention has been made in view of such a situation, and an object of the present invention is to calculate a moving picture coding that reduces coding amount of coding information and improves coding efficiency by calculating coding information candidates. To provide technology.

  In order to solve the above-described problem, a moving image encoding device according to an aspect of the present invention is a moving image encoding device that encodes the moving image using motion compensation in units of blocks obtained by dividing each picture of the moving image. Thus, a temporal merge candidate is obtained from inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded. In the merge mode in which inter prediction information is derived and inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is Reference index deriving unit (131) for deriving as reference index information of temporal merge candidates, and deriving Time merging candidate generator for deriving the inter prediction information of the time merge candidates based on the reference index information and a (132). The reference index deriving unit (131) includes reference index information of a prediction block adjacent to the left side of the prediction block to be encoded and a value of reference index information of a prediction block adjacent to the upper side of the prediction block to be encoded Is set as the reference index information of the time merge candidate.

  Another aspect of the present invention is also a moving image encoding apparatus. This apparatus is a moving picture encoding apparatus that encodes the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be encoded In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving unit (131) for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed And a time merge indication based on the derived reference index information Time merging candidate generator for deriving the inter prediction information and a (132). The reference index deriving unit (131) is (i) when a prediction block adjacent to either the left side or the upper side of the prediction block to be encoded is inter-predicted using a reference list to be derived The reference index information value of the prediction block adjacent to one of the sides is set as the reference index information of the reference list to be derived as a temporal merge candidate, and (ii) the prediction adjacent to the one side The block is not inter-predicted using the derivation reference list, and a prediction block adjacent to the other side of the one side is inter-predicted using the derivation reference list. When predicted, the value of the reference index information of the prediction block adjacent to the other side is set as the derivation target of the temporal merge candidate. To set the reference index information of the irradiation list.

  Yet another embodiment of the present invention is also a moving image encoding apparatus. This apparatus is a moving picture encoding apparatus that encodes the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be encoded In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving unit (131) for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed And a time merge indication based on the derived reference index information Time merging candidate generator for deriving the inter prediction information and a (132). The reference index deriving unit (131) is configured to: (i) when a prediction block adjacent to either the left side or the upper side of the prediction block to be encoded is inter predicted, When the prediction block adjacent to the prediction block is inter-predicted using the reference list to be derived, the value of the reference index information of the reference list to be derived of the prediction block adjacent to any one of the sides is set as the temporal merge candidate. If the prediction block adjacent to one of the sides is inter-predicted without using the derivation reference list, the derivation target of the temporal merge candidate is set in the reference index information of the derivation reference list The reference index information of the reference list is set to a default value, and (ii) a schedule adjacent to one of the sides is set. When a block is not inter-predicted and a prediction block adjacent to the other side of any one of the sides is inter-predicted, a prediction block adjacent to the other side is the derivation target When inter prediction is performed using a reference list, the value of the reference index information of the prediction block adjacent to the other side is set as the reference index information of the reference list to be derived as a temporal merge candidate, and the other side When the prediction block adjacent to is inter-predicted without using the derivation target reference list, the reference index information of the derivation target reference list of temporal merge candidates is set to a default value.

  Yet another embodiment of the present invention is also a moving image encoding apparatus. This apparatus is a moving picture encoding apparatus that encodes the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be encoded In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving unit (131) for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed And a time merge indication based on the derived reference index information Time merging candidate generator for deriving the inter prediction information and a (132). The reference index deriving unit (131) has a priority order to prioritize either the prediction block adjacent to the left side of the prediction block to be encoded or the prediction block adjacent to the upper side of the prediction block to be encoded, The value of the reference index information of any of the adjacent prediction blocks is set as the reference index information of the temporal merge candidate.

  Yet another aspect of the present invention is a video encoding method. This method is a moving picture coding method for coding the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be coded. In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving step for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed; Of time merge candidates based on the reference index information And a time merge candidate generating step of deriving the centers prediction information. In the reference index derivation step, the smaller of the reference index information of the prediction block adjacent to the left side of the encoding target prediction block and the reference index information of the prediction block adjacent to the upper side of the encoding prediction block Is set as the reference index information of the time merge candidate.

  Yet another embodiment of the present invention is also a moving image encoding method. This method is a moving picture coding method for coding the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be coded. In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving step for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed; Of time merge candidates based on the reference index information And a time merge candidate generating step of deriving the centers prediction information. In the reference index deriving step, (i) when a prediction block adjacent to either the left side or the upper side of the prediction block to be encoded is inter-predicted using the reference list to be derived, A value of reference index information of a prediction block adjacent to one of the sides is set as reference index information of the reference list to be derived as a temporal merge candidate, and (ii) a prediction block adjacent to one of the sides is Inter prediction is not performed using the derivation target reference list, and a prediction block adjacent to the other side of the one side is inter predicted using the derivation reference list The reference index information value of the prediction block adjacent to the other side is the reference of the derivation target of the temporal merge candidate Set to strike the reference index information.

  Yet another embodiment of the present invention is also a moving image encoding method. This method is a moving picture coding method for coding the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be coded. In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving step for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed; Of time merge candidates based on the reference index information And a time merge candidate generating step of deriving the centers prediction information. In the reference index derivation step, (i) when a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted, the reference index is derived. When the prediction block is inter-predicted using the derivation target reference list, the value of the reference index information of the derivation reference list of the prediction block adjacent to one of the sides is set as the temporal merge candidate derivation target When the prediction index set in the reference index information of the reference list and the prediction block adjacent to any one of the sides is inter-predicted without using the derivation reference list, the derivation reference list of temporal merge candidates (Ii) prediction block adjacent to one of the sides is set to a default value. When the prediction block adjacent to the other side of the one side is inter predicted, the prediction block adjacent to the other side is the derivation target. When the inter prediction is performed using the reference list, the value of the reference index information of the prediction block adjacent to the other side is set to the reference index information of the reference list to be derived as a temporal merge candidate, and the other When a prediction block adjacent to an edge is inter-predicted without using the derivation target reference list, reference index information of the derivation target reference list of temporal merge candidates is set to a default value.

  Yet another embodiment of the present invention is also a moving image encoding method. This method is a moving picture coding method for coding the moving picture using motion compensation in units of blocks obtained by dividing each picture of the moving picture, and is encoded differently in time from the prediction block to be coded. In this picture, inter prediction information that is a temporal merge candidate is derived from inter prediction information of a prediction block that exists at or near the same position as the prediction block to be encoded, and the encoding is performed based on the derived inter prediction information. A reference index deriving step for deriving reference index information for identifying a reference picture used in the prediction block to be encoded as reference index information of a temporal merge candidate in a merge mode in which inter prediction of the target prediction block is performed; Of time merge candidates based on the reference index information And a time merge candidate generating step of deriving the centers prediction information. The reference index derivation step is a priority order that gives priority to either the prediction block adjacent to the left side of the prediction block to be encoded or the prediction block adjacent to the upper side of the prediction block to be encoded. The value of the reference index information of the adjacent prediction block is set as the reference index information of the temporal merge candidate.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to reduce the amount of generated code of encoded information to be transmitted and improve the encoding efficiency.

It is a block diagram which shows the structure of the moving image encoder which performs the motion vector prediction method which concerns on embodiment. It is a block diagram which shows the structure of the moving image decoding apparatus which performs the motion vector prediction method which concerns on embodiment. It is a figure explaining a tree block and an encoding block. It is a figure explaining the division mode of a prediction block. It is a figure explaining the prediction block of the spatial merge candidate in merge mode. It is a figure explaining the prediction block of the spatial merge candidate in merge mode. It is a figure explaining the prediction block of the spatial merge candidate in merge mode. It is a figure explaining the prediction block of the spatial merge candidate in merge mode. It is a figure explaining the prediction block of the time merge candidate in merge mode. It is a figure explaining the syntax of the bit stream in the slice level regarding merge mode. It is a figure explaining the syntax of the bit stream in the prediction block level regarding merge mode. It is a figure explaining an example of the entropy code | symbol of the syntax element of a merge index. It is a block diagram which shows the detailed structure of the inter prediction information derivation | leading-out part of the moving image encoder of FIG. It is a block diagram which shows the detailed structure of the inter prediction information derivation | leading-out part of the moving image decoding apparatus of FIG. It is a flowchart explaining a merge candidate derivation process in merge mode and a merge candidate list construction process. It is a flowchart explaining the space merge candidate derivation | leading-out process of merge mode. 10 is a flowchart for explaining a reference index derivation processing procedure for temporal merge candidates in the merge mode according to the method of the first embodiment. 12 is a flowchart for explaining a reference index derivation processing procedure of a temporal merge candidate in a merge mode according to the method of the second embodiment. 10 is a flowchart for explaining a reference index derivation processing procedure for temporal merge candidates in a merge mode according to the method of the third embodiment. 15 is a flowchart for describing a reference index derivation processing procedure for temporal merge candidates in the merge mode according to the method of the fourth embodiment. FIG. 10 is a flowchart for describing a reference index derivation processing procedure for a merged time temporal merge candidate according to the method of the fifth embodiment. It is a flowchart explaining the time merge candidate derivation | leading-out process procedure of merge mode. It is a flowchart explaining the derivation | leading-out process procedure of the picture of the time from which merge mode differs. It is a flowchart explaining the derivation | leading-out process procedure of the prediction block of the picture of the time from which merge mode differs. It is a flowchart explaining the time merge candidate derivation | leading-out process procedure of merge mode. It is a flowchart explaining the time merge candidate derivation | leading-out process procedure of merge mode. It is a flowchart explaining the scaling calculation processing procedure of a motion vector. It is a flowchart explaining the scaling calculation processing procedure of a motion vector. It is a flowchart explaining the registration processing procedure of the merge candidate to the merge candidate list | wrist of merge mode. Conventional MPEG-4 AVC / H. It is a figure explaining the H.264 time direct mode.

  In the present embodiment, with regard to moving picture coding, in particular, to improve coding efficiency in moving picture coding in which a picture is divided into rectangular blocks of an arbitrary size and shape and motion compensation is performed in units of blocks between pictures. Next, a plurality of predicted motion vectors are derived from the motion vectors of the block adjacent to the encoding target block or the block of the encoded picture, and the difference vector between the motion vector of the encoding target block and the selected prediction motion vector The amount of code is reduced by calculating and encoding. Alternatively, the coding amount is reduced by deriving the coding information of the coding target block by using the coding information of the block adjacent to the coding target block or the block of the coded picture. Also, in the case of decoding a moving image, a plurality of predicted motion vectors are calculated from the motion vectors of a block adjacent to the decoding target block or a decoded picture block, and selected from the difference vector decoded from the encoded stream The motion vector of the decoding target block is calculated from the predicted motion vector and decoded. Alternatively, the encoding information of the decoding target block is derived by using the encoding information of the block adjacent to the decoding target block or the block of the decoded picture.

  First, techniques used in the present embodiment and technical terms are defined.

(About tree blocks and coding blocks)
In the embodiment, as shown in FIG. 3, the picture is equally divided into square units of any same size. This unit is defined as a tree block, and is an encoding / decoding target block in a picture (an encoding target block in the encoding process and a decoding target block in the decoding process. Hereinafter, unless otherwise specified, It is used as a basic unit of address management for specifying. Except for monochrome, the tree block is composed of one luminance signal and two color difference signals. The size of the tree block can be freely set to a power of 2 depending on the picture size and the texture in the picture. In order to optimize the encoding process according to the texture in the picture, the tree block divides the luminance signal and chrominance signal in the tree block hierarchically into four parts (two parts vertically and horizontally) as necessary, The block can be made smaller in block size. Each block is defined as a coding block, and is a basic unit of processing when performing coding and decoding. Except for monochrome, the coding block is also composed of one luminance signal and two color difference signals. The maximum size of the coding block is the same as the size of the tree block. An encoded block having the minimum size of the encoded block is called a minimum encoded block, and can be freely set to a power of 2.

  In FIG. 3, the encoding block A is a single encoding block without dividing the tree block. The encoding block B is an encoding block formed by dividing a tree block into four. The coding block C is a coding block obtained by further dividing the block obtained by dividing the tree block into four. The coding block D is a coding block obtained by further dividing the block obtained by dividing the tree block into four parts and further dividing the block into four twice hierarchically, and is a coding block of the minimum size.

(About prediction mode)
Encoded / decoded in units of coding blocks (used in encoded processing for encoded picture, predicted block, image signal, etc., and used in decoded processing for decoded picture, predicted block, image signal, etc.) (Used in this sense unless otherwise noted.) Intra prediction (MODE_INTRA) in which prediction is performed from surrounding image signals, and inter prediction (MODE_INTER) in which prediction is performed from encoded / decoded picture image signals Switch. A mode for identifying the intra prediction (MODE_INTRA) and the 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, and can be selected and encoded.

(About split mode, prediction block, prediction unit)
When performing intra prediction (MODE_INTRA) and inter prediction (MODE_INTER) by dividing the picture into blocks, the coded block is divided as necessary to reduce the unit for switching the intra prediction and inter prediction methods. Make predictions. A mode for identifying the division method of the luminance signal and the color difference signal of the coding block is defined as a division mode (PartMode). Furthermore, this divided block is defined as a prediction block. As shown in FIG. 4, four types of partition modes (PartMode) are defined according to the method of dividing the luminance signal of the coding block. The division mode (PartMode) of what is regarded as one prediction block without dividing the luminance signal of the coding block (FIG. 4A) is 2N × 2N division (PART_2Nx2N), and the luminance signal of the coding block is horizontally The division mode (PartMode) of the two prediction blocks (FIG. 4B) is divided into 2N × N divisions (PART_2NxN), the luminance signal of the encoded block is divided in the vertical direction, and the encoded block is The division mode (PartMode) of the two prediction blocks (FIG. 4 (c)) is N × 2N division (PART_Nx2N), and the luminance signal of the encoded block is divided into four prediction blocks by horizontal and vertical equal divisions. The division mode (PartMode) of (FIG. 4D) is defined as N × N division (PART_NxN), respectively. Except for N × N division (PART_NxN) of intra prediction (MODE_INTRA), the color difference signal is also divided for each division mode (PartMode) in the same manner as the vertical / horizontal division ratio of the luminance signal.

  In order to specify each prediction block within the coding block, a number starting from 0 is assigned to the prediction block existing inside the coding block in the coding order. This number is defined as a split index PartIdx. A number described in each prediction block of the encoded block in FIG. 4 represents a partition index PartIdx of the prediction block. In the 2N × N division (PART_2NxN) shown in FIG. 4B, the division index PartIdx of the upper prediction block is set to 0, and the division index PartIdx of the lower prediction block is set to 1. In the N × 2N division (PART_Nx2N) shown in FIG. 4C, the division index PartIdx of the left prediction block is set to 0, and the division index PartIdx of the right prediction block is set to 1. In the N × N partition (PART_NxN) shown in FIG. 4D, the partition index PartIdx of the upper left prediction block is 0, the partition index PartIdx of the upper right prediction block is 1, and the partition index PartIdx of the lower left prediction block is 2. And the division index PartIdx of the prediction block at the lower right is set to 3.

  When the prediction mode (PredMode) is inter prediction (MODE_INTER), except for the coding block D which is the smallest coding block, the partition mode (PartMode) is 2N × 2N partition (PART_2Nx2N), 2N × N partition (PART_2NxN), and N × 2N partition (PART_Nx2N) is defined, and only the coding block D which is the smallest coding block, the partition mode (PartMode) is 2N × 2N partition (PART_2Nx2N), 2N × N partition (PART_2NxN), and N × 2N In addition to the division (PART_Nx2N), N × N division (PART_NxN) is defined. The reason why N × N division (PART_NxN) is not defined other than the smallest coding block is that, except for the smallest coding block, the coding block can be divided into four to represent a small coding block.

(Position of tree block, coding block, prediction block, transform block)
The position of each block including the tree block, the encoding block, the prediction block, and the transform block according to the present embodiment has the position of the pixel of the luminance signal at the upper left of the luminance signal screen as the origin (0, 0). The pixel position of the upper left luminance signal included in each block area is represented by two-dimensional coordinates (x, y). The direction of the coordinate axis is a right direction in the horizontal direction and a downward direction in the vertical direction, respectively, and the unit is one pixel unit of the luminance signal. Of course, the luminance signal and the color difference signal have the same image size (number of pixels) and the color difference format is 4: 4: 4. Of course, the luminance signal and the color difference signal have a different color size format of 4: 4. Even in the case of 2: 0, 4: 2: 2, the position of each block of the color difference signal is represented by the coordinates of the pixel of the luminance signal included in the block area, and the unit is one pixel of the luminance signal. In this way, not only can the position of each block of the color difference signal be specified, but also the relationship between the positions of the luminance signal block and the color difference signal block can be clarified only by comparing the coordinate values.

(Inter prediction mode, reference list)
In the embodiment of the present invention, in inter prediction in which prediction is performed from an image signal of a coded / decoded picture, a plurality of decoded pictures can be used as reference pictures. In order to identify a reference picture selected from a plurality of reference pictures, a reference index is attached to each prediction block. In the B slice, any two reference pictures can be selected for each prediction block and inter prediction can be performed. As inter prediction modes, there are L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI). The reference picture is managed by L0 (reference list 0) and L1 (reference list 1) of the list structure, and the reference picture can be specified by specifying the reference index of L0 or L1. L0 prediction (Pred_L0) is inter prediction that refers to a reference picture managed in L0, L1 prediction (Pred_L1) is inter prediction that refers to a reference picture managed in L1, and bi-prediction (Pred_BI) is This is inter prediction in which both L0 prediction and L1 prediction are performed and one reference picture managed by each of L0 and L1 is referred to. Only L0 prediction can be used in inter prediction of P slice, and L0 prediction, L1 prediction, and bi-prediction (Pred_BI) that averages or weights and adds L0 prediction and L1 prediction can be used in inter prediction of B slice. In the subsequent processing, it is assumed that the constants and variables with the subscript LX in the output are processed for each of L0 and L1.

(Merge mode, merge candidate)
The merge mode does not encode / decode inter prediction information such as a prediction mode, a reference index, and a motion vector of a prediction block to be encoded / decoded, but within the same picture as a prediction block to be encoded / decoded. The prediction block adjacent to the prediction block to be encoded / decoded, or the same position as the prediction block to be encoded / decoded of a coded / decoded picture that is temporally different from the prediction block to be encoded / decoded or its position In this mode, inter prediction is performed by deriving inter prediction information of a prediction block to be encoded / decoded from inter prediction information of a prediction block existing in the vicinity (neighboring position). The prediction block adjacent to the prediction block to be encoded / decoded in the same picture as the prediction block to be encoded / decoded and inter prediction information of the prediction block are spatial merge candidates, the prediction block to be encoded / decoded, and the time. Prediction information derived from a prediction block existing at the same position as or near (previously near) a prediction block to be encoded / decoded of a differently encoded / decoded picture and inter prediction information of the prediction block Are time merge candidates. Each merge candidate is registered in the merge candidate list, and the merge candidate used in the inter prediction is specified by the merge index.

(About adjacent prediction blocks)
5, 6, 7 and 8 are diagrams for explaining a prediction block adjacent to a prediction block to be encoded / decoded within the same picture as the prediction block to be encoded / decoded. FIG. 9 shows an already encoded / decoded prediction in an encoded / decoded picture that is temporally different from the prediction block to be encoded / decoded and exists at or near the same position as the prediction block to be encoded / decoded. It is a figure explaining a block. A prediction block adjacent in the spatial direction of a prediction block to be encoded / decoded and a prediction block at the same position at different times will be described with reference to FIGS. 5, 6, 7, 8, and 9. FIG.

  As shown in FIG. 5, a prediction block A adjacent to the left side of the prediction block to be encoded / decoded in the same picture as the prediction block to be encoded / decoded, a prediction block B adjacent to the upper side, A prediction block C adjacent to the upper right vertex, a prediction block D adjacent to the lower left vertex, and a prediction block E adjacent to the upper left vertex are defined as prediction blocks adjacent in the spatial direction.

  As shown in FIG. 6, when the size of the prediction block adjacent to the left side of the prediction block to be encoded / decoded is smaller than the prediction block to be encoded / decoded, and there are a plurality of prediction blocks, this embodiment In the embodiment, only the lowest prediction block A10 among the prediction blocks adjacent to the left side is set as the prediction block A adjacent to the left side.

  Similarly, when the size of the prediction block adjacent to the upper side of the prediction block to be encoded / decoded is smaller than the prediction block to be encoded / decoded, and there are a plurality of prediction blocks, the left side in the present embodiment Only the rightmost prediction block B10 among the prediction blocks adjacent to is assumed as the prediction block B1 adjacent to the upper side.

  In addition, as shown in FIG. 7, even when the size of the prediction block F adjacent to the left side of the prediction block to be encoded / decoded is larger than the prediction block to be encoded / decoded, it is adjacent to the left side according to the above condition. If the prediction block F is adjacent to the left side of the prediction block to be encoded / decoded, the prediction block A is determined. If the prediction block F is adjacent to the lower left vertex of the prediction block to be encoded / decoded, the prediction block D is determined. If it is adjacent to the top left vertex of the prediction block to be encoded / decoded, the prediction block E is determined. In the example of FIG. 6, the prediction block A, the prediction block E, and the prediction block E are the same prediction block.

  As shown in FIG. 8, even when the size of the prediction block G adjacent to the upper side of the prediction block to be encoded / decoded is larger than the prediction block to be encoded / decoded, it is adjacent to the upper side according to the above condition. If the prediction block G is adjacent to the upper side of the prediction block to be encoded / decoded, the prediction block B is determined. If the prediction block G is adjacent to the upper right vertex of the prediction block to be encoded / decoded, the prediction block C is determined. If it is adjacent to the top left vertex of the prediction block to be encoded / decoded, the prediction block E is determined. In the example of FIG. 8, the prediction block B, the prediction block C, and the prediction block E are the same prediction block.

  As shown in FIG. 9, in an already encoded / decoded picture that is temporally different from the prediction block to be encoded / decoded, an already encoded / decoded picture that exists at or near the same position as the prediction block to be encoded / decoded. The decoded prediction blocks T0 and T1 are defined as prediction blocks at the same position at different times.

(About POC)
POC is a variable associated with the picture to be encoded, and is set to a value that increases by 1 in the picture output / display order. Based on the POC value, it is possible to determine whether they are the same picture, to determine the front-to-back relationship between pictures in the output / display order, or to derive the distance between pictures. For example, if the POCs of two pictures have the same value, it can be determined that they are the same picture. When the POCs of two pictures have different values, it can be determined that the picture with the smaller POC value is the picture to be output / displayed first, and the difference between the POCs of the two pictures is the time axis direction difference between the pictures. Indicates distance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a moving picture coding apparatus according to an embodiment of the present invention. The moving image encoding apparatus according to the embodiment includes an image memory 101, a motion vector detection unit 102, a difference motion vector calculation unit 103, an inter prediction information derivation unit 104, a motion compensation prediction unit 105, an intra prediction unit 106, and a prediction method determination unit. 107, residual signal generation section 108, orthogonal transform / quantization section 109, first encoded bit string generation section 110, second encoded bit string generation section 111, multiplexing section 112, inverse quantization / inverse orthogonal transform section 113, a decoded image signal superimposing unit 114, an encoded information storage memory 115, and a decoded image memory 116.

  The image memory 101 temporarily stores the image signal of the encoding target picture supplied in the order of shooting / display time. The image memory 101 supplies the stored image signal of the picture to be encoded to the motion vector detection unit 102, the prediction method determination unit 107, and the residual signal generation unit 108 in units of predetermined pixel blocks. At this time, the image signals of the pictures stored in the order of shooting / display time are rearranged in the encoding order and output from the image memory 101 in units of pixel blocks.

  The motion vector detection unit 102 uses the motion vector for each prediction block size and each prediction mode by block matching between the image signal supplied from the image memory 101 and the reference picture supplied from the decoded image memory 116 for each prediction block. Detection is performed in units, and the detected motion vector is supplied to the motion compensation prediction unit 105, the difference motion vector calculation unit 103, and the prediction method determination unit 107.

  The difference motion vector calculation unit 103 calculates a plurality of motion vector predictor candidates by using the encoded information of the already encoded image signal stored in the encoded information storage memory 115, and generates a prediction motion vector list. The optimum motion vector predictor is selected from a plurality of motion vector predictor candidates registered and registered in the motion vector predictor list, and a motion vector difference is calculated from the motion vector detected by the motion vector detector 102 and the motion vector predictor. Then, the calculated difference motion vector is supplied to the prediction method determination unit 107. Furthermore, a prediction motion vector index that identifies a prediction motion vector selected from prediction motion vector candidates registered in the prediction motion vector list is supplied to the prediction method determination unit 107.

  The inter prediction information deriving unit 104 derives merge candidates in the merge mode. A plurality of merge candidates are derived using the encoding information of the already encoded prediction block stored in the encoding information storage memory 115 and registered in a merge candidate list described later, and registered in the merge candidate list Flags predFlagL0 [xP] [yP], predFlagL1 [xP indicating whether or not to use the L0 prediction and L1 prediction of each prediction block of the selected merge candidate from among a plurality of merge candidates ] [yP], reference index refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], motion vector mvL0 [xP] [yP], mvL1 [xP] [yP] etc. And a merge index for specifying the selected merge candidate is supplied to the prediction method determination unit 107. Here, xP and yP are indexes indicating the position of the upper left pixel of the prediction block in the picture. The detailed configuration and operation of the inter prediction information deriving unit 104 will be described later.

  The motion compensated prediction unit 105 generates a predicted image signal by inter prediction (motion compensated prediction) from the reference picture using the motion vectors detected by the motion vector detection unit 102 and the inter prediction information deriving unit 104, and generates the predicted image signal. This is supplied to the prediction method determination unit 107. In L0 prediction and L1 prediction, one-way prediction is performed. In the case of bi-prediction (Pred_BI), bi-directional prediction is performed, the inter-predicted signals of L0 prediction and L1 prediction are adaptively multiplied by weighting factors, offset values are added and superimposed, and finally A predicted image signal is generated.

  The intra prediction unit 106 performs intra prediction for each intra prediction mode. A prediction image signal is generated by intra prediction from the decoded image signal stored in the decoded image memory 211, a suitable intra prediction mode is selected from a plurality of intra prediction modes, the selected intra prediction mode, and A prediction image signal corresponding to the selected intra prediction mode is supplied to the prediction method determination unit 107.

  The prediction method determination unit 107 evaluates the encoding information and the code amount of the residual signal, the distortion amount between the prediction image signal and the image signal, and the like, so that the optimum coding block unit can be selected from a plurality of prediction methods. In prediction mode PredMode to determine whether it is inter prediction (PRED_INTER) or intra prediction (PRED_INTRA), and partition mode PartMode are determined. Determines the merge index, and if not in the merge mode, the inter prediction mode, the prediction motion vector index, the L0 and L1 reference indexes, the difference motion vector, etc. are determined, and the encoded information corresponding to the determination is determined as the first encoded bit string generator. 110.

  Furthermore, the prediction method determination unit 107 stores information indicating the determined prediction method and encoded information including a motion vector corresponding to the determined prediction method in the encoded information storage memory 115. The encoded information stored here is a flag predFlagL0 [xP] [yP], predFlagL1 [indicating whether to use the prediction mode PredMode, the partition mode PartMode, the L0 prediction of each prediction block, and the L1 prediction of each prediction block. xP] [yP], L0, L1 reference indices refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], L0, L1 motion vectors mvL0 [xP] [yP], mvL1 [xP] [yP], etc. It is. Here, xP and yP are indexes indicating the position of the upper left pixel of the prediction block in the picture. When the prediction mode PredMode is inter prediction (MODE_INTER), a flag predFlagL0 [xP] [yP] indicating whether to use L0 prediction and a flag predFlagL1 [xP] [yP] indicating whether to use L1 prediction are Both are zero. On the other hand, when the prediction mode PredMode is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), the flag predFlagL0 [xP] [yP] indicating whether to use L0 prediction is 1, L1 prediction is used. The flag predFlagL1 [xP] [yP] indicating whether or not is zero. When the inter prediction mode is L1 prediction (Pred_L1), the flag predFlagL0 [xP] [yP] indicating whether to use L0 prediction is 0, and the flag predFlagL1 [xP] [yP] indicating whether to use L1 prediction is 1. When the inter prediction mode is bi-prediction (Pred_BI), a flag predFlagL0 [xP] [yP] indicating whether to use L0 prediction and a flag predFlagL1 [xP] [yP] indicating whether to use L1 prediction are both 1. It is. The prediction method determination unit 107 supplies a prediction image signal corresponding to the determined prediction mode to the residual signal generation unit 108 and the decoded image signal superimposition unit 114.

The residual signal generation unit 108 generates a residual signal by performing subtraction between the image signal to be encoded and the predicted image signal, and supplies the residual signal to the orthogonal transform / quantization unit 109.
The orthogonal transform / quantization unit 109 performs orthogonal transform and quantization on the residual signal in accordance with the quantization parameter to generate an orthogonal transform / quantized residual signal, and a second encoded bit string generation unit 111 and the inverse quantization / inverse orthogonal transform unit 113. Further, the orthogonal transform / quantization unit 109 stores the quantization parameter in the encoded information storage memory 115.

  The first encoded bit string generation unit 110, in addition to information in units of sequences, pictures, slices, and encoded blocks, codes corresponding to the prediction method determined by the prediction method determination unit 107 for each encoded block and predicted block Encoding information is encoded. Specifically, in the prediction mode PredMode, partition mode PartMode, and inter prediction (PRED_INTER) for each coding block, a flag that determines whether or not the mode is merge mode, merge index in the case of merge mode, and inter prediction in the case of not in merge mode Encoding information such as information on the mode, the predicted motion vector index, and the difference motion vector is encoded according to a prescribed syntax rule to be described later to generate a first encoded bit string, which is supplied to the multiplexing unit 112.

  The second encoded bit string generation unit 111 generates a second encoded bit string by entropy-encoding the orthogonally transformed and quantized residual signal according to a specified syntax rule, and supplies the second encoded bit string to the multiplexing unit 112. The multiplexing unit 112 multiplexes the first encoded bit string and the second encoded bit string in accordance with a prescribed syntax rule, and outputs a bit stream.

  The inverse quantization / inverse orthogonal transform unit 113 performs inverse quantization and inverse orthogonal transform on the orthogonal transform / quantized residual signal supplied from the orthogonal transform / quantization unit 109 to calculate a residual signal, and performs decoding. This is supplied to the image signal superimposing unit 114. The decoded image signal superimposing unit 114 superimposes the predicted image signal according to the determination by the prediction method determining unit 107 and the residual signal subjected to inverse quantization and inverse orthogonal transform by the inverse quantization / inverse orthogonal transform unit 113 to decode the decoded image. Is generated and stored in the decoded image memory 116. Note that the decoded image may be stored in the decoded image memory 116 after filtering processing for reducing distortion such as block distortion due to encoding.

    FIG. 2 is a block diagram showing the configuration of the moving picture decoding apparatus according to the embodiment of the present invention corresponding to the moving picture encoding apparatus of FIG. The moving picture decoding apparatus according to the embodiment includes a separation unit 201, a first encoded bit string decoding unit 202, a second encoded bit string decoding unit 203, a motion vector calculation unit 204, an inter prediction information derivation unit 205, and a motion compensation prediction unit 206. , An intra prediction unit 207, an inverse quantization / inverse orthogonal transform unit 208, a decoded image signal superimposing unit 209, an encoded information storage memory 210, and a decoded image memory 211.

  The decoding process of the moving picture decoding apparatus in FIG. 2 corresponds to the decoding process provided in the moving picture encoding apparatus in FIG. 1, so the motion compensation prediction unit 206 in FIG. The configuration of the inverse orthogonal transform unit 208, the decoded image signal superimposing unit 209, the encoded information storage memory 210, and the decoded image memory 211 is the same as that of the motion compensation prediction unit 105, the inverse quantization / inverse of the moving image encoding device in FIG. The orthogonal transform unit 113, the decoded image signal superimposing unit 114, the encoded information storage memory 115, and the decoded image memory 116 have functions corresponding to the respective configurations.

  The bit stream supplied to the separation unit 201 is separated according to a rule of a prescribed syntax, and the separated encoded bit string is supplied to the first encoded bit string decoding unit 202 and the second encoded bit string decoding unit 203.

  The first encoded bit string decoding unit 202 decodes the supplied encoded bit string to obtain sequence, picture, slice, encoded block unit information, and predicted block unit encoded information. Specifically, in the prediction mode PredMode for determining whether the prediction is inter prediction (PRED_INTER) or intra prediction (PRED_INTRA) for each coding block, split mode PartMode, and inter prediction (PRED_INTER), a flag for determining whether the mode is merge mode, When the merge mode is selected, the merge index is decoded. When the merge mode is not selected, the encoded information related to the inter prediction mode, the predicted motion vector index, the difference motion vector, and the like is decoded according to a predetermined syntax rule to be described later, and the encoded information is a motion vector calculation unit. 204, supplied to the inter prediction information deriving unit 205 or the intra prediction unit 207.

  The second encoded bit string decoding unit 203 calculates a residual signal that has been orthogonally transformed / quantized by decoding the supplied encoded bit string, and dequantized / inverted the residual signal that has been orthogonally transformed / quantized. This is supplied to the orthogonal transform unit 208.

  When the prediction mode PredMode of the prediction block to be decoded is inter prediction (PRED_INTER) and not the merge mode, the motion vector calculation unit 204 stores the encoded information of the already decoded image signal stored in the encoded information storage memory 210. A plurality of motion vector predictor candidates that are derived and registered in a motion vector predictor list to be described later, and a first encoded bit string decoding unit is selected from the motion vector predictor candidates registered in the motion vector predictor list A prediction motion vector corresponding to the prediction motion vector index decoded and supplied in 202 is selected, a motion vector is calculated from the difference vector decoded in the first encoded bit string decoding unit 202 and the selected prediction motion vector, The encoded information is supplied to the motion compensation prediction unit 206 and stored in the encoded information storage memory 210. To. The encoding information of the prediction block supplied / stored here is a flag predFlagL0 [xP] [yP], predFlagL1 [xP] [yP indicating whether to use the prediction mode PredMode, the partition mode PartMode, the L0 prediction, and the L1 prediction. ], L0, L1 reference indices refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], L0, L1 motion vectors mvL0 [xP] [yP], mvL1 [xP] [yP], and the like. Here, xP and yP are indexes indicating the position of the upper left pixel of the prediction block in the picture. When 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 the L0 prediction is 1, and the flag predFlagL1 indicating whether to use the L1 prediction is 0. It is. 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), a flag predFlagL0 indicating whether to use L0 prediction and a flag predFlagL1 indicating whether to use L1 prediction are both 1.

  The inter prediction information deriving unit 205 derives merge candidates when the prediction mode PredMode of the prediction block to be decoded is inter prediction (PRED_INTER) and in the merge mode. A plurality of merge candidates are derived and registered in a merge candidate list, which will be described later, using the encoded information of already decoded prediction blocks stored in the encoded information storage memory 115, and registered in the merge candidate list Whether a merge candidate corresponding to the merge index decoded and supplied by the first encoded bit string decoding unit 202 is selected from among a plurality of merge candidates, and whether to use the L0 prediction and the L1 prediction of the selected merge candidate PredFlagL0 [xP] [yP], predFlagL1 [xP] [yP], L0, L1 reference indices refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], L0, L1 motion vectors mvL0 [xP] Inter prediction information such as [yP] and mvL1 [xP] [yP] is supplied to the motion compensation prediction unit 206 and stored in the encoded information storage memory 210. Here, xP and yP are indexes indicating the position of the upper left pixel of the prediction block in the picture. The detailed configuration and operation of the inter prediction information deriving unit 205 will be described later.

  The motion compensation prediction unit 206 performs prediction by inter prediction (motion compensation prediction) from the reference picture stored in the decoded image memory 211 using the inter prediction information calculated by the motion vector calculation unit 204 or the inter prediction information deriving unit 205. An image signal is generated, and the predicted image signal is supplied to the decoded image signal superimposing unit 209. In the case of bi-prediction (Pred_BI), a weighted coefficient is adaptively multiplied and superimposed on the two motion-compensated predicted image signals of L0 prediction and L1 prediction to generate a final predicted image signal.

  The intra prediction unit 207 performs intra prediction when the prediction mode PredMode of the prediction block to be decoded is intra prediction (PRED_INTRA). The encoded information decoded by the first encoded bit string decoding unit includes an intra prediction mode, and by intra prediction from a decoded image signal stored in the decoded image memory 211 according to the intra prediction mode. A predicted image signal is generated, and the predicted image signal is supplied to the decoded image signal superimposing unit 209. Flags predFlagL0 [xP] [yP] and predFlagL1 [xP] [yP] indicating whether to use L0 prediction and L1 prediction are both set to 0 and stored in the encoded information storage memory 210. Here, xP and yP are indexes indicating the position of the upper left pixel of the prediction block in the picture.

  The inverse quantization / inverse orthogonal transform unit 208 performs inverse orthogonal transform and inverse quantization on the orthogonal transform / quantized residual signal decoded by the first encoded bit string decoding unit 202, and performs inverse orthogonal transform / An inverse quantized residual signal is obtained.

  The decoded image signal superimposing unit 209 performs the prediction image signal inter-predicted by the motion compensation prediction unit 206 or the prediction image signal intra-predicted by the intra prediction unit 207 and the inverse orthogonal transform by the inverse quantization / inverse orthogonal transform unit 208. The decoded image signal is decoded by superimposing the dequantized residual signal, and stored in the decoded image memory 211. When stored in the decoded image memory 211, the decoded image may be stored in the decoded image memory 211 after filtering processing that reduces block distortion or the like due to encoding is performed on the decoded image.

(About syntax)
Next, a syntax that is a common rule for encoding and decoding a bit stream of a moving image that is encoded by a moving image encoding device including the motion vector prediction method according to the present embodiment and decoded by the decoding device explain.

  FIG. 10 shows a first syntax structure described in the slice header in units of slices of the bitstream generated according to the present embodiment. However, only syntax elements relevant to the present embodiment are shown. When the slice type is a B slice, a picture colPic at a different time used in deriving a temporal motion vector predictor candidate or merge candidate is a L0 reference list of pictures including a prediction block to be processed or an L1 reference picture A flag collocated_from_l0_flag indicating which reference picture registered in the reference list is used is set. Details of the flag collocated_from_l0_flag will be described later.

  Note that the above syntax elements may be placed in a picture parameter set describing syntax elements set in units of pictures.

  FIG. 11 shows a syntax pattern described in units of prediction blocks. When the value of the prediction mode PredMode of the prediction block is inter prediction (MODE_INTER), merge_flag [x0] [y0] indicating whether the mode is the merge mode is set. Here, x0 and y0 are indices indicating the position of the upper left pixel of the prediction block in the picture of the luminance signal, and merge_flag [x0] [y0] is the prediction block located at (x0, y0) in the picture It is a flag indicating whether or not merge mode.

  Next, when merge_flag [x0] [y0] is 1, it indicates merge mode, and a merge list index syntax element merge_idx [x0] [y0] is set, which is a list of merge candidates to be referred to. . Here, x0 and y0 are indices indicating the position of the upper left pixel of the prediction block in the picture, and merge_idx [x0] [y0] is the merge index of the prediction block located at (x0, y0) in the picture. is there. FIG. 12 shows an example of the entropy code of the merge index syntax element merge_idx [x0] [y0]. In the present embodiment of the present invention, the number of merge candidates is set to five. When the merge index is 0, 1, 2, 3, 4, the signs of the merge index syntax elements merge_idx [x0] [y0] are “0”, “10”, “110”, “1110”, and “1111”, respectively. 'Become.

  On the other hand, when merge_flag [x0] [y0] is 0, it indicates that the mode is not merge mode. When the slice type is B slice, a syntax element inter_pred_flag [x0] [y0] for identifying the inter prediction mode is installed. The syntax element identifies L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI). For each of L0 and L1, syntax elements ref_idx_l0 [x0] [y0] and ref_idx_l1 [x0] [y0] of the reference index for specifying the reference picture, the motion vector and prediction of the prediction block obtained by motion vector detection The differential motion vector syntax elements mvd_l0 [x0] [y0] [j] and mvd_l1 [x0] [y0] [j], which are the differences from the motion vector, are provided. Here, x0 and y0 are indexes indicating the position of the upper left pixel of the prediction block in the picture, and ref_idx_l0 [x0] [y0] and mvd_l0 [x0] [y0] [j] are respectively (x0 , y0) is the reference index of L0 of the prediction block and the differential motion vector, and ref_idx_l1 [x0] [y0] and mvd_l1 [x0] [y0] [j] are respectively (x0, y0) in the picture It is the reference index of L1 of the prediction block located, and a difference motion vector. Further, j represents a differential motion vector component, j represents 0 as an x component, and j represents 1 as a y component. Next, syntax elements mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] of an index of a predicted motion vector list that is a list of predicted motion vector candidates to be referred to are set. Here, x0 and y0 are indices indicating the position of the upper left pixel of the prediction block in the picture, and mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] are in (x0, y0) in the picture It is the prediction motion vector index of L0 and L1 of the prediction block located. In the present embodiment of the present invention, the value of the number of candidates is set to 2.

  The inter prediction information deriving method according to the embodiment is implemented in the inter prediction information deriving unit 104 of the video encoding device in FIG. 1 and the inter prediction information deriving unit 205 of the video decoding device in FIG.

  An inter prediction information derivation method according to an embodiment will be described with reference to the drawings. The motion vector prediction method is performed in any of the encoding and decoding processes for each prediction block constituting the encoding block. When the prediction mode PredMode of the prediction block is inter prediction (MODE_INTER) and in the merge mode, in the case of encoding, the prediction block to be encoded using the prediction mode, reference index, and motion vector of the encoded prediction block When the prediction mode, the reference index, and the motion vector are derived, in the case of decoding, the prediction mode, the reference index, and the motion vector of the prediction block to be decoded using the prediction mode, the reference index, and the motion vector of the decoded prediction block It is carried out when deriving.

  The merge mode includes the prediction block A adjacent to the left, the prediction block B adjacent to the upper side, the prediction block C adjacent to the upper right, and the prediction block D adjacent to the lower left described with reference to FIGS. 5, 6, 7, and 8. In addition to the prediction block E adjacent to the upper left, five prediction blocks of the prediction block Col (either T0 or T1) existing at or near the same position at different times described with reference to FIG. 9 are candidates. . The inter prediction information deriving unit 104 of the moving image encoding device and the inter prediction information deriving unit 205 of the moving image decoding device register these candidates in the merge candidate list in a common order on the encoding side and the decoding side, The inter prediction information deriving unit 104 of the video encoding device determines a merge index for specifying an element of the merge candidate list, encodes it via the first encoded bit string generation unit, and performs inter prediction information of the video decoding device. The derivation unit 205 is supplied with the merge index decoded by the first encoded bit string decoding unit 202, selects a prediction block corresponding to the merge index from the merge candidate list, and refers to the prediction mode and reference of the selected merge candidate Motion compensation prediction is performed using inter prediction information such as an index and a motion vector.

  FIG. 13 is a diagram illustrating a detailed configuration of the inter prediction information deriving unit 104 of the video encoding device in FIG. FIG. 14 is a diagram illustrating a detailed configuration of the inter prediction information deriving unit 205 of the video decoding device in FIG.

  The portions surrounded by the thick frame lines in FIGS. 13 and 14 indicate the inter prediction information deriving unit 104 and the inter prediction information deriving unit 205, respectively.

  Furthermore, the part enclosed by the thick dotted line inside shows the operation | movement part of the inter prediction information derivation method mentioned later, and is similarly installed in the moving image decoding apparatus corresponding to the moving image encoding apparatus of embodiment. Thus, the same determination result consistent with encoding and decoding can be obtained.

  The inter prediction information deriving unit 104 includes a spatial merge candidate generating unit 130, a temporal merge candidate reference index deriving unit 131, a temporal merge candidate generating unit 132, a merge candidate registering unit 133, a merge candidate identical determining unit 134, and a merge candidate supplementing unit 135. , And an encoded information selection unit 136.

  The inter prediction information deriving unit 205 includes a spatial merge candidate generating unit 230, a temporal merge candidate reference index deriving unit 231, a temporal merge candidate generating unit 232, a merge candidate registering unit 233, a merge candidate identical determining unit 234, and a merge candidate supplementing unit 235. , And an encoding information selection unit 236.

  FIG. 15 is a merge candidate derivation process and a merge candidate list having functions common to the inter prediction information deriving unit 104 of the video encoding device and the inter prediction information deriving unit 205 of the video decoding device according to the embodiment of the present invention. It is a flowchart explaining the procedure of this construction process. Hereinafter, the processes will be described in order. In the following description, a case where the slice type slice_type is a B slice will be described unless otherwise specified, but the present invention can also be applied to a P slice. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  In the spatial merge candidate generating unit 130 of the inter prediction information deriving unit 104 of the moving image encoding device and the spatial merge candidate generating unit 230 of the inter prediction information deriving unit 205 of the moving image decoding device, each adjacent to the encoding / decoding target block. Spatial merge candidates A, B, C, D, and E are derived from the prediction blocks A, B, C, D, and E. Here, N indicating any of A, B, C, D, E, or Col is defined. A flag availableFlagN indicating whether the inter prediction information of the prediction block N can be used as the merge candidate N, a reference index refIdxL0N of L0 and a reference index refIdxL1N of L1, and an L0 prediction flag predFlagL0N and L1 prediction indicating whether L0 prediction is performed. The L1 prediction flag predFlagL1N indicating whether or not to be performed, the L0 motion vector mvL0N, and the L1 motion vector mvL1N are output (step S101). The detailed processing procedure of step S101 will be described later in detail using the flowchart of FIG.

  Subsequently, the temporal merge candidate reference index deriving unit 131 of the inter prediction information deriving unit 104 of the video encoding device and the temporal merge candidate reference index deriving unit 231 of the inter prediction information deriving unit 205 of the video decoding device A reference index of temporal merge candidates is derived from the prediction block adjacent to the quantization / decoding target block (step S102). When the inter prediction is performed using the inter prediction information of the temporal merge candidate when the slice type slice_type is P slice, only the L0 reference index is derived in order to perform the L0 prediction (Pred_L0), and the slice type slice_type is the B slice. When performing inter prediction using inter prediction information of temporal merge candidates, in order to perform bi-prediction (Pred_BI), respective reference indexes of L0 and L1 are derived. The detailed processing procedure of step S102 will be described later in detail using the flowchart of FIG.

  Subsequently, in the temporal merge candidate generating unit 132 of the inter prediction information deriving unit 104 of the video encoding device and the temporal merge candidate generating unit 232 of the inter prediction information deriving unit 205 of the video decoding device, time from pictures at different times A flag availableFlagCol indicating whether merge candidates can be derived and used, an L0 prediction flag predFlagL0Col indicating whether L0 prediction is performed, an L1 prediction flag predFlagL1Col indicating whether L1 prediction is performed, and a motion vector mvL0N of L0 The motion vector mvL1N of L1 is output (step S103). The detailed processing procedure of step S103 will be described later in detail using the flowchart of FIG.

  Subsequently, the merge candidate registration unit 133 of the inter prediction information deriving unit 104 of the video encoding device and the merge candidate registration unit 233 of the inter prediction information deriving unit 205 of the video decoding device create a merge candidate list mergeCandList and perform prediction. Vector candidates A, B, C, D, E, and Col are added (step S104). The detailed processing procedure of step S104 will be described later in detail using the flowchart of FIG.

  Subsequently, in the merge candidate identity determination unit 134 of the inter prediction information deriving unit 104 of the video encoding device and the merge candidate identity determination unit 234 of the inter prediction information deriving unit 205 of the video decoding device, in the merge candidate list mergeCandList, When the motion vectors of the same reference index have the same value, the merge candidate is removed except for the merge candidate in the smallest order (step S105).

  Subsequently, the merge candidate supplementing unit 135 of the inter prediction information deriving unit 104 of the video encoding device and the merge candidate supplementing unit 235 of the inter prediction information deriving unit 205 of the video decoding device are registered in the merge candidate list mergeCandList. The merge candidates are supplemented so that the number of merge candidates that are present becomes the specified number (step S106). In the present embodiment, the number of merge candidates is defined as five. The merge candidate list mergeCandList has a maximum number of merge candidates up to five, and the prediction mode in which the combination of L0 prediction and L1 prediction between already registered merge candidates is changed is a bi-prediction (Pred_BI) merge candidate or A merge candidate having a prediction mode having a value of (0, 0) at a different reference index and biprediction (Pred_BI) is added.

  Next, a method for deriving the merge candidate N from the prediction block N adjacent to the encoding / decoding target block, which is the processing procedure of step S101 in FIG. 15, will be described in detail. FIG. 16 is a flowchart for explaining the spatial merge candidate derivation processing procedure in step S101 of FIG. In N, A (left side), B (upper side), C (upper right), D (lower left), or E (upper left) representing an area of an adjacent prediction block is entered. In the present embodiment, a maximum of four spatial merge candidates are derived from five adjacent prediction blocks.

  In FIG. 15, the encoding information of the prediction block A adjacent to the left side of the prediction block to be encoded / decoded is checked with the variable N as A, the merge candidate A is derived, and the prediction block adjacent to the upper side with the variable N as B The encoding information of B is examined to derive a merge candidate B, the variable N is set as C, the encoding information of the prediction block C adjacent on the upper right side is checked, the merge candidate C is derived, and the variable N is set as D to the lower left side. The encoding information of the adjacent prediction block D is checked to derive the merge candidate D, and the variable N is set as E to check the encoding information of the prediction block E adjacent to the upper left to derive the merge candidate E (step S1101 to step S1101). S1112).

  First, when the variable N is E and the values of the flags availableFlagA, availableFlagB, availableFlagC, and availableFlagD are added and the total is 4 (YES in step S1102), that is, when four spatial merge candidates are derived, the merge candidate E The flag availableFlagE is set to 0 (step S1105), the motion vectors mvL0E and mvL1E of the merge candidate E are both set to (0, 0) (step S1106), and the values of the flags predFlagL0E and predFlagL1E of the merge candidate E are both set. It is set to 0 (step S1107), and the space merge candidate derivation process is terminated. In the present embodiment, four merge candidates are derived from adjacent prediction blocks. Therefore, when four spatial merge candidates are already derived, it is not necessary to perform further spatial merge candidate derivation processing.

  On the other hand, if the variable N is not E, or the values of the flags availableFlagA, availableFlagB, availableFlagC, and availableFlagD are added and the total is not 4 (NO in step S1102), the prediction block N adjacent to the prediction block to be encoded / decoded is If each prediction block N is specified, the encoding information of the prediction block N is acquired from the encoding information storage memory 115 or 210 (step S1103).

  When the adjacent prediction block N cannot be used or the prediction mode PredMode of the prediction block N is intra prediction (MODE_INTRA) (NO in step S1104), the value of the flag availableFlagN of the merge candidate N is set to 0 (step S1105). The values of the motion vectors mvL0N and mvL1N of the merge candidate N are both set to (0, 0) (step S1106), and the values of the flags predFlagL0N and predFlagL1N of the merge candidate N are both set to 0 (step S1107).

  On the other hand, when the adjacent prediction block N can be used and the prediction mode PredMode of the prediction block N is not intra prediction (MODE_INTRA) (YES in step S1104), the inter prediction information of the prediction block N is used as the inter prediction information of the merge candidate N. . The value of the flag availableFlagN of the merge candidate N is set to 1 (step S1108), and the motion vectors mvL0N and mvL1N of the merge candidate N are respectively used as the motion vectors mvL0N [xN] [yN] and mvL1N [xN] [yN] of the prediction block N. (Step S1109), the reference indexes refIdxL0N and refIdxL1N of the merge candidate N are set to the same values as the reference indexes refIdxL0 [xN] [yN] and refIdxL1 [xN] [yN] of the prediction block N, respectively ( In step S1110), the flags predFlagL0N and predFlagL1N of the merge candidate N are set to the flags predFlagL0 [xN] [yN] and predFlagL1 [xN] [yN] of the prediction block N, respectively (step S1111). Here, xN and yN are indexes indicating the position of the upper left pixel of the prediction block N in the picture.

  The processes in steps S1102 to S1111 are repeated for N = A, B, C, D, and E (steps S1101 to S1112).

  Next, a method for deriving the reference index of the time merge candidate in S102 of FIG. 15 will be described in detail. The reference indices of L0 and L1 as temporal merge candidates are derived.

  In the present embodiment, the reference index of the temporal merge candidate is derived using the reference index of the spatial merge candidate, that is, the reference index used in the prediction block adjacent to the encoding / decoding target block. This is because when the temporal merge candidate is selected, the reference index of the prediction block to be encoded / decoded has a high correlation with the reference index of the prediction block adjacent to the encoding / decoding target block to be the spatial merge candidate. It is. In particular, in the present embodiment, only the reference indexes of the prediction block A adjacent to the left side of the prediction block to be encoded / decoded and the prediction block B adjacent to the upper side are used. This is because prediction blocks A and B that are in contact with a side of a prediction block to be encoded / decoded among adjacent prediction blocks A, B, C, D, and E that are also spatial merge candidates are predicted to be encoded / decoded. This is because the correlation is higher than prediction blocks C, D, and E that are in contact with only the vertices of the block. By limiting the prediction blocks to be used to the prediction blocks A and B without using the prediction blocks C, D, and E having relatively low correlation, the effect of improving the coding efficiency by deriving the reference index of the temporal merge candidate In addition, the amount of computation and the amount of memory access related to the reference index derivation process of the temporal merge candidate are reduced.

  Hereinafter, this embodiment will be described by dividing it into several examples. First, Example 1 of the present embodiment will be described. In Example 1 of this embodiment, both the prediction block A and the prediction block B are LX predictions (L0 or L1, the list from which the reference index of the temporal merge candidate is derived is LX, and prediction using the LX is LX prediction. In the following description, unless otherwise noted, this is used in this sense.) The smaller LX reference index value of the prediction block A and prediction block B is used as the LX reference index value of the temporal merge candidate. To do. However, when only one of the prediction block A and the prediction block B is subjected to LX prediction, the LX reference index value of the prediction block on which LX prediction is performed is adopted as the LX reference index value of the temporal merge candidate. When both the prediction block A and the prediction block B do not perform LX prediction, the value of the reference index of the LX that is a temporal merge candidate is set to 0 as the default value.

  When both the prediction block A and the prediction block B do not perform LX prediction, the default value of the reference index of the LX that is a temporal merge candidate is set to 0 because the reference picture corresponding to the reference index value of 0 is the most in inter prediction. This is because the probability of being selected is high. However, the present invention is not limited to this, and the default value of the reference index may be a value other than 0 (1, 2, etc.), and the default value of the reference index may be set in the encoded stream at the sequence level, picture level, or slice level. The syntax element shown may be installed and transmitted so that it can be selected on the encoding side.

  FIG. 17 is a flowchart for describing the reference index derivation processing procedure of the time merge candidate in step S102 of FIG. 15 according to the method of Example 1 of the present embodiment. First, the encoding information of the prediction block A adjacent to the left and the encoding information of the prediction block B are acquired from the encoding information storage memory 115 or 210 (steps S2101 and S2102). The subsequent processing from step S2104 to step S2110 is performed in each of L0 and L1 (steps S2103 to S2111). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  When both the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B are not 0 (in step S2104) YES), the LX reference index refIdxLXCol of the temporal merge candidate is the smaller of the LX reference index refIdxLX [xA] [yA] of the prediction block A and the LX reference index refIdxLX [xB] [yB] of the prediction block B The same value is set (step S2105). Here, xA and yA are indexes indicating the position of the upper left pixel of the prediction block A in the picture. Here, xB and yB are indexes indicating the position of the upper left pixel of the prediction block B in the picture.

  In the present embodiment, in the prediction block N (N = A, B), when the prediction block N cannot be used outside the slice to be encoded / decoded or the prediction block N is encoded in the encoding / decoding order. / A flag indicating whether or not to use L0 prediction when it is not encoded / decoded after the prediction block to be decoded and cannot be used, or when the prediction mode PredMode of the prediction block N is inter prediction (MODE_INTER) Both predFlagL0 [xN] [yN] and the flag predFlagL1 [xN] [yN] indicating whether to use the L1 prediction of the prediction block N are 0. Here, xN and yN are indexes indicating the position of the upper left pixel of the prediction block N in the picture. When the prediction mode PredMode of the prediction block N is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), the flag predFlagL0 [xN] [yN] indicating whether to use the L0 prediction of the prediction block N is 1 , Flag predFlagL1 [xN] [yN] indicating whether to use L1 prediction is zero. When the inter prediction mode of the prediction block N is L1 prediction (Pred_L1), a flag predFlagL0 [xN] [yN] indicating whether or not to use the L0 prediction of the prediction block N is 0 and a flag indicating whether or not to use the L1 prediction predFlagL1 [xN] [yN] is 1. When the inter prediction mode of the prediction block N is bi-prediction (Pred_BI), a flag predFlagL0 [xN] [yN] indicating whether to use the L0 prediction of the prediction block N, and a flag predFlagL1 [indicating whether to use the L1 prediction xN] [yN] are both 1.

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is not 0 and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B is 0 (NO in step S2104, YES in step S2106), the LX reference index refIdxLXCol of the temporal merge candidate is set to the same value as the LX reference index refIdxLX [xA] [yA] of the prediction block A (step S2107). Here, xA and yA are indexes indicating the position of the upper left pixel of the prediction block A in the picture, and xB and yB are indexes indicating the position of the upper left pixel of the prediction block B in the picture.

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is 0 and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B is not 0 ( In step S2104 NO, step S2106 NO, step S2108 YES), the LX reference index refIdxLXCol of the temporal merge candidate is set to the same value as the LX reference index predFlagLX [xB] [yB] of the prediction block B ( Step S2109).

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B are both 0 (step S2104) NO in step S2106 and NO in step S2108), the reference index refIdxLXCol of the LX that is a candidate for time merge is set to a default value of 0 (step S2110).

  The processing from step S2104 to step S2110 performed in each of L0 and L1 is performed (steps S2103 to S2111), and this reference index derivation processing is terminated.

  Next, Example 2 which is a modification of Example 1 of the present embodiment will be described. Example 2 of the present embodiment differs from Example 1 in the processing procedure, but the same result is obtained. Also in the second embodiment, as in the first embodiment, the reference indexes of the prediction block A adjacent to the left side and the prediction block B adjacent to the upper side are used to refer to the LX of the prediction block A and the prediction block B. The smaller index value is adopted as the LX reference index value of the temporal merge candidate. However, when the prediction block A and the prediction block B do not perform LX prediction, the difference is that the LX reference index value of the prediction block is set to a large value. Accordingly, it is possible to perform the condition determination without distinguishing between the case where LX prediction is performed and the case where LX prediction is not performed. If a smaller reference index value is acquired, a reference index value which performs LX prediction is acquired. Therefore, processing can be simplified.

  FIG. 18 is a flow chart for explaining the procedure for deriving the reference index of the time merge candidate in step S102 of FIG. 15 by the method of Example 2 of the present embodiment. First, the encoding information of the prediction block A adjacent to the left and the encoding information of the prediction block B are acquired from the encoding information storage memory 115 or 210 (steps S2201 and S2202). The subsequent processing from step S2204 to step S2210 is performed in each of L0 and L1 (steps S2203 to S2211). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is not 0 (YES in step S2204), the process proceeds to step S2206, and when the flag predFlagLX [xA] [yA] is 0 ( In step S2204, the LX reference index refIdxLX [xA] [yA] of the prediction block A is set to the specified value MAX_REF_IDX (step S2205).

  Subsequently, when the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B is not 0 (YES in step S2206), the process proceeds to step S2208, and the flag predFlagLX [xB] [yB] is 0. If there is (NO in step S2206), the LX reference index refIdxLX [xB] [yB] of the prediction block B is set to the specified value MAX_REF_IDX (step S2207).

  Subsequently, the LX reference index refIdxLXCol of the temporal merge candidate is set to the smaller of the LX reference index refIdxLX [xA] [yA] of the prediction block A and the LX reference index refIdxLX [xB] [yB] of the prediction block B. The same value is set (step S2208).

  Subsequently, if the LX reference index refIdxLXCol of the time merge candidate is the specified value MAX_REF_IDX (YES in step S2209), the LX reference index refIdxLXCol of the time merge candidate is set to a default value 0 (step S2210). However, the default value of the reference index may be a value other than 0 (1, 2, etc.) as in the first embodiment, and the default value of the reference index may be set in the encoded stream at the sequence level, the picture level, or the slice level. The syntax element shown may be installed and transmitted so that it can be selected on the encoding side.

  The processing from step S2204 to step S2210 performed in each of L0 and L1 is performed (steps S2203 to S2211), and this reference index derivation processing is terminated.

  Next, Example 3 of the present embodiment will be described. Also in Example 3 of the present embodiment, temporal merging is performed using the reference indexes of the prediction block A adjacent to the left side and the prediction block B adjacent to the upper side as in Example 1 and Example 2. A candidate reference index is derived. Compared to the first embodiment, the processing of step S2104 and step S2105 in FIG. 17 is omitted, it is determined whether or not LX prediction is performed in the order of the prediction block A and the prediction block B, and the LX prediction found first is determined. The difference is that the processing amount is further reduced by adopting the reference index of the prediction block to be performed. When the prediction block A performs LX prediction, the LX reference index of the prediction block A is adopted as the value of the LX reference index of the temporal merge candidate, the prediction block A does not perform LX prediction, and the prediction block B performs LX prediction. When performing, the LX reference index of the prediction block B is adopted as the value of the LX reference index of the temporal merge candidate. When both the prediction block A and the prediction block B do not perform LX prediction, the value of the reference index of the LX that is a temporal merge candidate is set to 0 as a default value. However, as in the first and second embodiments, in the third embodiment, the default value of the reference index may be set to a value other than 0 (1, 2, etc.), and encoding is performed at the sequence level, picture level, or slice level. A syntax element indicating the default value of the reference index may be installed in the stream so that it can be transmitted and can be selected on the encoding side.

  FIG. 19 is a flow chart for explaining the procedure for deriving the reference index of the time merge candidate in step S102 of FIG. 15 according to the method of Example 3 of the present embodiment. First, the encoding information of the prediction block A adjacent to the left and the encoding information of the prediction block B are acquired from the encoding information storage memory 115 or 210 (steps S2301 and S2302). The subsequent processing from step S2304 to step S2308 is performed in each of L0 and L1 (steps S2303 to S2309). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  If the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is not 0 (YES in step S2304), the LX reference index refIdxLXCol of the temporal merge candidate is used as the LX reference index refIdxLX of the prediction block A. The same value as [xA] [yA] is set (step S2305).

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is 0 and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B is not 0 ( In step S2304 (NO in step S2306, YES), the LX reference index refIdxLXCol of the temporal merge candidate is set to the same value as the LX reference index predFlagLX [xB] [yB] of the prediction block B (step S2307).

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction for the prediction block A and the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction for the prediction block B are both 0 (step S2304). In step S2306, the reference index refIdxLXCol of the LX that is a candidate for time merge is set to a default value of 0 (step S2308).

  The processing from step S2304 to step S2308 performed in each of L0 and L1 is performed (steps S2303 to S2309), and this reference index derivation processing is terminated.

  In Example 3 of the present embodiment, since the reference index of the prediction block that performs LX prediction that is found first is adopted as the reference index of the temporal merge candidate, a plurality of prediction blocks are used as in Example 1 and Example 2. It is not necessary to compare the size of the reference indexes, and the amount of calculation can be reduced.

  In Example 3 of the present embodiment, whether or not LX prediction is performed in the order of the prediction block A adjacent to the left side and the prediction block B adjacent to the upper side is first determined. Although it has been described that the reference index of the prediction block that performs LX prediction is adopted as the reference index of the temporal merge candidate, whether or not LX prediction is performed in the order of the prediction block B and the prediction block A is determined and found first A predictive index can also be employed.

  Next, Example 4 of the present embodiment will be described. Also in Example 4 of the present embodiment, the reference indexes of the prediction block A adjacent to the left side and the prediction block B adjacent to the upper side are used as in Example 1, Example 2, and Example 3. Then, the reference index of the temporal merge candidate is derived. Compared to the third embodiment, it is determined whether or not to perform inter prediction in the order of the prediction block A and the prediction block B, and the processing amount is further increased by adopting the prediction index of the prediction block that performs the inter prediction first found. The difference is that it reduces. When the prediction mode (PredMode) of the prediction block A is inter prediction (MODE_INTER), the LX reference index of the prediction block A is adopted as the value of the LX reference index of the temporal merge candidate. At this time, when the prediction block A does not perform LX prediction, the reference index of the LX that is a temporal merge candidate is set to 0 as a default value. When the prediction mode (PredMode) of the prediction block A is not inter prediction (MODE_INTER) and the prediction mode (PredMode) of the prediction block B is inter prediction (MODE_INTER), the LX reference index of the prediction block B is used as the time merge candidate LX. It is adopted as the value of the reference index. At this time, if the prediction block B does not perform LX prediction, the reference index of the LX as a temporal merge candidate is set to 0 as a default value. When both the prediction modes (PredMode) of the prediction block A and the prediction block B are not inter prediction (MODE_INTER), the value of the reference index of the LX as a temporal merge candidate is set to 0 as a default value. However, as in the first, second, and third embodiments, the default value of the reference index may be a value other than 0 (1, 2, etc.) in the fourth embodiment, and the sequence level, picture level, or slice A syntax element indicating the default value of the reference index may be installed and transmitted in the encoded stream at the level, and may be selected on the encoding side.

  FIG. 20 is a flow chart for explaining the procedure for deriving the reference index of the time merge candidate in step S102 of FIG. 15 according to the method of Example 4 of the present embodiment. First, the encoding information of the prediction block A adjacent to the left and the encoding information of the prediction block B are acquired from the encoding information storage memory 115 or 210 (steps S2401 and S2402).

  Subsequently, when the prediction block A can be used and the prediction mode (PredMode) of the prediction block A is intra prediction (MODE_INTRA) (YES in step S2403), that is, the prediction mode (PredMode) of the prediction block A is inter prediction (MODE_INTER). ), The process proceeds to step S2404. If the prediction mode (PredMode) of the prediction block A is not inter prediction (MODE_INTER), the process proceeds to step S2409.

  The subsequent processing from step S2405 to step S2407 is performed in each of L0 and L1 (steps S2404 to S2408). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is not 0 (YES in step S2405), the LX reference index refIdxLXCol of the temporal merge candidate is used as the LX reference index refIdxLX of the prediction block A. [xA] [yA] is set to the same value (step S2406), and if the flag predFlagLX [xA] [yA] is 0 (NO in step S2405), the reference index refIdxLXCol of the LX as a time merge candidate is set to 0 (Step S2407).

  The processing from step S2405 to step S2407 performed in each of L0 and L1 is performed (steps S2404 to S2408), and this reference index derivation processing is terminated.

  On the other hand, in step S2409, when the prediction block B can be used and the prediction mode (PredMode) of the prediction block B is intra prediction (MODE_INTRA) (YES in step S2409), that is, the prediction mode (PredMode) of the prediction block B is inter. In the case of prediction (MODE_INTER), the process proceeds to step S2410, and when the prediction mode (PredMode) of the prediction block A is not inter prediction (MODE_INTER), the process proceeds to step S2415.

  The subsequent processing from step S2411 to step S2413 is performed in each of L0 and L1 (steps S2410 to S2414). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  When the flag predFlagLX [xB] [yB] indicating whether to perform LX prediction of the prediction block B is not 0 (YES in step S2411), the LX reference index refIdxLXCol of the temporal merge candidate is used as the LX reference index refIdxLX of the prediction block B. Set to the same value as [xB] [yB] (step S2412), and if the flag predFlagLX [xB] [yB] is 0 (NO in step S2411), set the reference index refIdxLXCol of the LX as a time merge candidate to 0 (Step S2413).

  The processing from step S2410 to step S2413 performed in each of L0 and L1 is performed (steps S2409 to S2414), and this reference index derivation processing is terminated.

  On the other hand, in steps S2415 to S2417, both the reference index refIdxL0Col for L0 and the reference index refIdxL1Col for L1 are set to 0 (step S2416), and this reference index derivation process is terminated.

  In Example 4 of the present embodiment, the L0 and L1 reference indexes of the temporal merge candidate can be derived from one prediction block, so that the reference index of the temporal merge candidate can be easily managed, and encoding / decoding of the temporal merge candidate is performed. Processing can be simplified.

  In Example 4 of the present embodiment, whether or not to perform inter prediction in the order of the prediction block A adjacent to the left side and the prediction block B adjacent to the upper side was first found. Although it demonstrated as employ | adopting the reference index of the prediction block which performs inter prediction, it is determined whether inter prediction is performed in the order of the prediction block B and the prediction block A, and the prediction block which performs the inter prediction first discovered is determined. A predictive index can also be employed.

  Next, Example 5 of the present embodiment will be described. In Example 5 of the present embodiment, the reference index of the temporal merge candidate is derived using the reference index of the prediction block A adjacent to the left side. The third embodiment is different from the third embodiment in that the processing amount is further reduced by omitting the processes of steps S2302, S2306, and S2307 of FIG. When the prediction block A performs LX prediction (LX is a list from which a reference index is derived), the LX reference index of the prediction block A is adopted as the LX reference index value of the temporal merge candidate, and the prediction block A performs LX prediction. If not performed, the reference index value of the LX as a time merge candidate is set to 0 as the default value. However, as in the first, second, third, and fourth embodiments, in the fifth embodiment, when the prediction block A does not perform LX prediction, the default value of the reference index is set to a value other than 0 (1, 2). Or a syntax element indicating the default value of the reference index in the encoded stream at the sequence level, picture level, or slice level so that it can be transmitted and selected on the encoding side. Also good.

  FIG. 21 is a flow chart for explaining the procedure for deriving the reference index of the time merge candidate in step S102 of FIG. 15 by the method of Example 5 of the present embodiment. First, the encoding information of the prediction block A adjacent to the left is acquired from the encoding information storage memory 115 or 210 (step S2501). The subsequent processing from step S2503 to step S2505 is performed in each of L0 and L1 (steps S2502 to S2506). Note that LX is set to L0 when deriving the L0 reference index of the temporal merge candidate, and LX is set to L1 when deriving the L1 reference index. However, when the slice type slice_type is a P slice, only the L0 prediction (Pred_L0) is provided as the inter prediction mode, and there is no L1 prediction (Pred_L1) and bi-prediction (Pred_BI). Therefore, the processing related to L1 can be omitted.

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is not 0 (YES in step S2503), the LX reference index refIdxLXCol of the temporal merge candidate is used as the LX reference index refIdxLX of the prediction block A. The same value as [xA] [yA] is set (step S2504).

  When the flag predFlagLX [xA] [yA] indicating whether to perform LX prediction of the prediction block A is 0 (NO in step S2503), the reference index refIdxLXCol of the LX that is a temporal merge candidate is set to 0 (step S2505). .

  The processing from step S2503 to step S2505 performed in each of L0 and L1 is performed (steps S2502 to S2506), and this reference index derivation processing is terminated.

  In Example 5 of the present embodiment, it has been described that the reference index of the temporal merge candidate is derived using the reference index of the prediction block A adjacent to the left side, but it is adjacent to the left side. Instead of the prediction block A, the reference index of the temporal merge candidate can be derived using the prediction block B adjacent to the upper side.

  Next, the method for deriving merge candidates at different times in S103 of FIG. 15 will be described in detail. FIG. 22 is a flowchart illustrating the time merge candidate derivation processing procedure in step S103 of FIG.

  First, a picture colPic at a different time is derived from the slice type slice_type and the above-described flag collocated_from_l0_flag (step S3101).

  FIG. 23 is a flowchart for explaining the procedure for deriving the picture colPic at different times in step S3101 of FIG. When the slice type slice_type is a B slice and the above-described flag collocated_from_l0_flag is 0 (YES in step S3201 and YES in step S3202), RefPicList1 [0], that is, a picture colPic at a time when the pictures with the reference index 0 in the reference list L1 are different (Step S3203). Otherwise, that is, when the slice type slice_type is B slice and the aforementioned flag collocated_from_l0_flag is 1 (YES in step S3201, NO in step S3202), or when the slice type slice_type is P slice (NO in step S3201 and YES in S3204) ), RefPicList0 [0], that is, the picture colPic of the reference list L0 with the reference index 0 is a different time (step S3205).

  Next, returning to the flowchart of FIG. 22, a prediction block colPU at a different time is derived, and encoded information is acquired (step S3102).

  FIG. 24 is a flowchart for explaining the procedure for deriving the prediction block colPU of the picture colPic at different times in step S3102 of FIG.

  First, a prediction block located at the lower right (outside) of the same position as a processing target prediction block in a picture colPic at a different time is set as a prediction block colPU at a different time (step S3301). This prediction block corresponds to the prediction block T0 in FIG.

  Next, encoding information of the prediction block colPU at different times is acquired (step S3302). When PredMode of a prediction block colPU at a different time cannot be used, or when the prediction mode PredMode of a prediction block colPU at a different time is intra prediction (MODE_INTRA) (YES in step S3303, YES in step S3304), the picture colPic in a different time The prediction block located in the upper left center of the same position as the processing target prediction block is set as a prediction block colPU at a different time (step S3305). This prediction block corresponds to the prediction block T1 in FIG.

  Next, returning to the flowchart of FIG. 22, a flag indicating whether or not the L0 predicted motion vector mvL0Col and the temporal merge candidate Col derived from the prediction block of another picture at the same position as the prediction block to be encoded / decoded are valid. In addition to deriving availableFlagL0Col (step S3103), a flag availableFlagL1Col indicating whether the prediction motion vector mvL1Col of L1 and the temporal merge candidate Col are valid is derived. Further, when the flag availableFlagL0Col or the flag availableFlagL1Col is 1, a flag availableFlagCol indicating whether the time merge candidate Col is valid is set to 1.

  FIG. 25 is a flowchart for explaining the procedure for deriving the inter prediction information of the temporal merge candidate in steps S3103 and S3104 in FIG. In L0 or L1, the list of time merge candidate derivation targets is LX, and the prediction using LX is LX prediction. Hereinafter, unless otherwise noted, this meaning is used. LX becomes L0 when called as step S3103, which is a time merge candidate L0 derivation process, and LX becomes L1, when called as step S3104, which is a time merge candidate L1 derivation process.

  When the prediction mode PredMode of the prediction block colPU at different time is intra prediction (MODE_INTRA) or cannot be used (NO in step S3401 and NO in step S3402), both the flag availableFlagLXCol and the flag predFlagLXCol are set to 0 (step S3403), and the motion vector mvLXCol Is set to (0, 0) (step S3404), and the process of deriving inter prediction information of the current time merge candidate ends.

  When the prediction block colPU is available and the prediction mode PredMode is not intra prediction (MODE_INTRA) (YES in step S3401 and YES in step S3402), mvCol, refIdxCol, and availableFlagCol are derived by the following procedure.

  When the flag PredFlagL0 [xPCol] [yPCol] indicating whether or not the L0 prediction of the prediction block colPU is used (YES in step S3405), the prediction mode of the prediction block colPU is Pred_L1, and therefore the motion vector mvCol is predicted. The same value as MvL1 [xPCol] [yPCol] that is the L1 motion vector of the block colPU is set (step S3406), and the reference index refIdxCol is set to the same value as the reference index RefIdxL1 [xPCol] [yPCol] of L1 (step S3406). In step S3407, the list ListCol is set to L1 (step S3408). Here, xPCol and yPCol are indexes indicating the position of the upper left pixel of the prediction block colPU in the picture colPic at different times.

  On the other hand, when the L0 prediction flag PredFlagL0 [xPCol] [yPCol] of the prediction block colPU is not 0 (NO in step S3405 in FIG. 25), it is determined whether the L1 prediction flag PredFlagL1 [xPCol] [yPCol] of the prediction block colPU is 0. To do. When the L1 prediction flag PredFlagL1 [xPCol] [yPCol] of the prediction block colPU is 0 (YES in step S3409), the motion vector mvCol becomes the same value as MvL0 [xPCol] [yPCol], which is the L0 motion vector of the prediction block colPU. It is set (step S3410), the reference index refIdxCol is set to the same value as the reference index RefIdxL0 [xPCol] [yPCol] of L0 (step S3411), and the list ListCol is set to L0 (step S3412).

  When the L0 prediction flag PredFlagL0 [xPCol] [yPCol] of the prediction block colPU and the L1 prediction flag PredFlagL1 [xPCol] [yPCol] of the prediction block colPU are not 0 (NO in step S3405, NO in step S3409), the prediction block colPU Since the inter prediction mode is bi-prediction (Pred_BI), one of the two motion vectors L0 and L1 is selected (step S3413).

  FIG. 26 is a flowchart illustrating a procedure for deriving inter prediction information of temporal merge candidates when the inter prediction mode of the prediction block colPU is bi-prediction (Pred_BI).

  First, it is determined whether or not the POC of all the pictures registered in all the reference lists is smaller than the POC of the current encoding / decoding target picture (step S3501), and L0 which is all the reference lists of the prediction block colPU. When the POC of all the pictures registered in L1 is smaller than the POC of the current encoding / decoding target picture (YES in step S3501), LX is L0, that is, the motion vector of L0 of the encoding / decoding target picture If the prediction vector candidate is derived (YES in step S3502), the inter prediction information of L0 of the prediction block colPU is selected, and LX is L1, that is, the prediction of the motion vector of L1 of the encoding / decoding target picture. When the vector candidate is derived (NO in step S3502), the prediction block colPU L1 To select the inter prediction information. On the other hand, when at least one of the POCs of pictures registered in all the reference lists L0 and L1 of the prediction block colPU is larger than the POC of the current encoding / decoding target picture (NO in step S3501), the flag collocated_from_l0_flag is 0. (YES in step S3503), the L0 inter prediction information of the prediction block colPU is selected. If the flag collocated_from_l0_flag is 1 (NO in step S3503), the L1 inter prediction information of the prediction block colPU is selected. To do.

  When the inter prediction information of L0 of the prediction block colPU is selected (YES in step, YES in step S3503), the motion vector mvCol is set to the same value as MvL0 [xPCol] [yPCol] (step S3504), and the reference index refIdxCol is set to the same value as RefIdxL0 [xPCol] [yPCol] (step S3505), and the list ListCol is set to L0 (step S3506).

  When the inter prediction information of L1 of the prediction block colPU is selected (NO in step S2502 and NO in step S3503), the motion vector mvCol is set to the same value as MvL1 [xPCol] [yPCol] (step S3507), see The index refIdxCol is set to the same value as RefIdxL1 [xPCol] [yPCol] (step S3508), and the list ListCol is set to L1 (step S3509).

  Returning to FIG. 25, if inter prediction information can be acquired from the prediction block colPU, both the flag availableFlagLXCol and the flag predFlagLXCol are set to 1 (step S3414).

  Subsequently, the motion vector mvCol is scaled to obtain an LX motion vector mvLXCol as a temporal merge candidate (step S3415). This motion vector scaling calculation processing procedure will be described with reference to FIGS. 27 and 28. FIG.

  FIG. 27 is a flowchart showing the motion vector scaling calculation processing procedure in step S3105 of FIG.

The inter-picture distance td is derived by subtracting the POC of the reference picture corresponding to the reference index refIdxCol referenced in the list ListCol of the prediction block colPU from the POC of the picture colPic at different times (step S3601). Note that when the POC of the reference picture referenced in the list Col of the prediction block colPU is earlier in the display order than the picture colPic at a different time, the inter-picture distance td is a positive value, and the prediction is more accurate than the picture colPic at a different time. When the POC of the reference picture referenced in the list ListCol of the block colPU is later in the display order, the inter-picture distance td becomes a negative value.
td = POC of picture colPic at different time-POC of reference picture referenced by list ListCol of prediction block colPU

The inter-picture distance tb is derived by subtracting the POC of the reference picture corresponding to the LX reference index of the temporal merge candidate derived in step S102 of FIG. 15 from the POC of the current encoding / decoding target picture (step S3602). . When the reference picture referred to in the current encoding / decoding target picture list LX is earlier in the display order than the current encoding / decoding target picture, the inter-picture distance tb becomes a positive value, When the reference picture referred to in the encoding / decoding target picture list LX is later in the display order, the inter-picture distance tb is a negative value.
tb = POC of current encoding / decoding target picture—POC of reference picture corresponding to LX reference index of temporal merge candidate

Subsequently, the inter-picture distances td and tb are compared (step S3603). If the inter-picture distances td and tb are equal (YES in step S3603), the LX motion vector mvLXCol as a temporal merge candidate is set to the same value as the motion vector mvCol. After setting (step S3604), the scaling calculation process is terminated.
mvLXCol = mvCol

On the other hand, when the inter-picture distances td and tb are not equal (NO in step S3603), scaling calculation processing is performed by multiplying mvCol by the scaling coefficient tb / td according to the following equation (step S3605), and the scaled time merge candidate Obtain the motion vector mvLXCol of LX.
mvLXCol = tb / td * mvCol

  FIG. 28 shows an example of the case where the scaling operation in step S3605 is performed with integer precision arithmetic. The processing in steps S3606 to S3608 in FIG. 28 corresponds to the processing in step S3605 in FIG.

  First, as in the flowchart of FIG. 27, the inter-picture distance td and the inter-picture distance tb are derived (steps S3601 and S3602).

Subsequently, the inter-picture distances td and tb are compared (step S3603). If the inter-picture distances td and tb are equal (YES in step S3603), as in the flowchart of FIG. Is set to the same value as the motion vector mvCol (step S3604), and this scaling calculation process is terminated.
mvLXCol = mvCol

On the other hand, if the inter-picture distances td and tb are not equal (NO in step S3603), a variable tx is derived from the following equation (step S3606).
tx = (16384 + Abs (td / 2)) / td

Subsequently, the scaling coefficient DistScaleFactor is derived by the following equation (step S3607).
DistScaleFactor = (tb * tx + 32) >> 6

Subsequently, a scaled temporal merge candidate LX motion vector mvLXCol is obtained by the following equation (step S3608).
mvLXCol = ClipMv (Sign (DistScaleFactor * mvCol) * ((Abs (DistScaleFactor * mvCol) + 127) >> 8))

  Next, a method for registering the merge candidate in step S104 of FIG. 15 in the merge candidate list will be described in detail. FIG. 29 is a flowchart showing the procedure for registering merge candidates in the merge candidate list. In this method, priorities are assigned and the motion vector candidates are registered in the merge candidate list mergeCandList in descending order of priority, thereby reducing the code amount of the merge index merge_idx [x0] [y0]. The amount of codes is reduced by placing elements with higher priorities in front of the merge candidate list. For example, when there are five elements in the merge candidate list mergeCandList, the index 0 of the merge candidate list is “0”, the index 1 is “10”, the index 2 is “110”, the index 3 is “1110”, and the index 4 is “ By setting “11110”, the code amount representing the index 0 becomes 1 bit, and the code amount is reduced by registering an element considered to have a high occurrence frequency in the index 0.

  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 merge candidates corresponding to the index as elements. The number of the merge index starts from 0, and merge candidates are stored in the storage area of the merge candidate list mergeCandList. In the subsequent processing, a prediction block that is a merge candidate of the merge index i registered in the merge candidate list mergeCandList is represented by mergeCandList [i], and is distinguished from the merge candidate list mergeCandList by array notation. To do.

First, when availableFlagA is 1 (YES in step S4101), merge candidate A is registered at the head of the merge candidate list mergeCandList (step S4102).
Subsequently, when availableFlagB is 1 (YES in step S4103), merge candidate B is registered at the end of the merge candidate list mergeCandList (step S4104).
Subsequently, when availableFlagC is 1 (YES in step S4105), the merge candidate C is registered at the end of the merge candidate list mergeCandList (step S4106).
Subsequently, when availableFlagD is 1 (YES in step S4107), the merge candidate D is registered at the end of the merge candidate list mergeCandList (step S4108).
Subsequently, when availableFlagE is 1 (YES in step S4109), the merge candidate E is registered at the end of the merge candidate list mergeCandList (step S4110).
Subsequently, when availableFlagCol is 1 (YES in step S4109), the merge candidate Col is registered at the end of the merge candidate list mergeCandList (step S4110).

  In the merge mode, the prediction block A adjacent to the left and the prediction block B adjacent to the top often move together with the prediction block to be encoded / decoded. When the information can be acquired, the merge candidates A and B are registered ahead of the merge candidate list in preference to the other merge candidates C, D, E, and Col.

  In FIG. 13, the encoding information selection unit 136 of the inter prediction information deriving unit 104 of the video encoding device selects a merge candidate from the merge candidates registered in the merge candidate list, and merge index and merge index are selected. The inter prediction information of the merge candidate corresponding to is supplied to the motion compensation prediction unit 105.

  In selecting a merge candidate, the same method as the prediction method determination unit 107 can be used. For each merge candidate, the coding information and the coding amount of the residual signal and the coding distortion between the predicted image signal and the image signal are derived, and the merge candidate that produces the least generated code amount and coding distortion is determined. The For each merge candidate, entropy coding is performed on the merge index syntax element merge_idx, which is coding information in the merge mode, and the code amount of the coding information is calculated. Further, for each merge candidate, a predicted image signal motion-compensated according to the inter prediction information of each merge candidate by the same method as the motion compensation prediction unit 105, and an encoding target image signal supplied from the image memory 101, The amount of code of the prediction residual signal obtained by encoding the prediction residual signal is calculated. Coding information, that is, the total generated code amount obtained by adding the code amount of the merge index and the code amount of the prediction residual signal is calculated as an evaluation value.

  Further, after encoding such a prediction residual signal, it is decoded for distortion amount evaluation, and the encoding distortion is calculated as a ratio representing an error from the original image signal caused by the encoding. By comparing the total generated code amount and the encoding distortion for each merge candidate, encoding information with a small generated code amount and encoding distortion is determined. A merge index corresponding to the determined encoding information is encoded as a flag merge_idx represented by a second syntax pattern in units of prediction blocks. The generated code amount calculated here is preferably a simulation of the encoding process, but can be approximated or approximated easily.

  On the other hand, in FIG. 14, the encoding information selection unit 236 of the inter prediction information deriving unit 205 of the moving image encoding device performs a merge corresponding to the supplied merge index from among the merge candidates registered in the merge candidate list. A candidate is selected, and the inter prediction information of the merge candidate is supplied to the motion compensation prediction unit 206 and stored in the encoded information storage memory 210.

  The moving image encoded stream output from the moving image encoding apparatus of the embodiment described above has a specific data format so that it can be decoded according to the encoding method used in the embodiment. Therefore, the moving picture decoding apparatus corresponding to the moving picture encoding apparatus can decode the encoded stream of this specific data format.

  When a wired or wireless network is used to exchange an encoded stream between a moving image encoding device and a moving image decoding device, the encoded stream is converted into a data format suitable for the transmission form of the communication path. It may be transmitted. In that case, a video transmission apparatus that converts the encoded stream output from the video encoding apparatus into encoded data in a data format suitable for the transmission form of the communication channel and transmits the encoded data to the network, and receives the encoded data from the network Then, a moving image receiving apparatus that restores the encoded stream and supplies the encoded stream to the moving image decoding apparatus is provided.

  The moving image transmitting apparatus is a memory that buffers the encoded stream output from the moving image encoding apparatus, a packet processing unit that packetizes the encoded stream, and transmission that transmits the packetized encoded data via the network. Part. The moving image receiving apparatus generates a coded stream by packetizing the received data, a receiving unit that receives the packetized coded data via a network, a memory that buffers the received coded data, and packet processing. And a packet processing unit provided to the video decoding device.

  The above processing relating to encoding and decoding can be realized as a transmission, storage, and reception device using hardware, and is stored in a ROM (Read Only Memory), a flash memory, or the like. It can also be realized by firmware or software such as a computer. The firmware program and software program can be recorded on a computer-readable recording medium, provided from a server through a wired or wireless network, or provided as a data broadcast of terrestrial or satellite digital broadcasting Is also possible.

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

  DESCRIPTION OF SYMBOLS 101 Image memory, 102 Motion vector detection part, 103 Difference motion vector calculation part, 104 Inter prediction information derivation part, 105 Motion compensation prediction part, 106 Intra prediction part, 107 Prediction method determination part, 108 Residual signal generation part, 109 Orthogonal Transform / quantization unit, 110 first encoded bit string generation unit, 111 second encoded bit string generation unit, 112 multiplexing unit, 130 spatial merge candidate generation unit, 131 time merge candidate reference index deriving unit, 132 time Merge candidate generation unit, 133 Merge candidate registration unit, 134 Merge candidate identity determination unit, 135 Merge candidate supplementation unit, 136 Encoding information selection unit, 201 Separation unit, 202 First encoded bit sequence decoding unit, 203 Second encoded bit sequence Decoding unit, 204 motion vector calculation unit 205 Inter prediction information derivation unit, 206 Motion compensation prediction unit, 207 Intra prediction unit, 208 Inverse quantization / inverse orthogonal transform unit, 209 Decoded image signal superimposing unit, 210 Encoded information storage memory, 211 Decoded image memory, 230 Spatial merge A candidate generation unit, a 231 time merge candidate reference index derivation unit, a 232 time merge candidate generation unit, a 233 merge candidate registration unit, a 234 merge candidate identity determination unit, a 235 merge candidate supplement unit, and a 236 encoding information selection unit.

Claims (12)

A moving image encoding device that encodes the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving unit derived as reference index information of
A temporal merge candidate generator for deriving inter prediction information of temporal merge candidates based on the derived reference index information,
The reference index derivation unit has a smaller value of reference index information of a prediction block adjacent to the left side of the prediction block to be encoded and reference index information of a prediction block adjacent to an upper side of the prediction block to be encoded Is set in the reference index information of the temporal merge candidate. A moving image encoding device that encodes the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving unit derived as reference index information of
A temporal merge candidate generator for deriving inter prediction information of temporal merge candidates based on the derived reference index information,
The reference index derivation unit includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted using a reference list to be derived, the prediction block is adjacent to the one side Set the value of the reference index information of the prediction block to the reference index information of the reference list of the derivation target of the temporal merge candidate,
(Ii) When a prediction block adjacent to one of the sides is not inter-predicted using the reference list to be derived, and adjacent to the other side with respect to the one of the sides When the prediction block is inter-predicted using the derivation reference list, the value of the reference index information of the prediction block adjacent to the other side is used as the reference index information of the derivation reference list of temporal merge candidates. A moving image encoding device, characterized by: setting. A moving image encoding device that encodes the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving unit derived as reference index information of
A temporal merge candidate generator for deriving inter prediction information of temporal merge candidates based on the derived reference index information,
The reference index derivation unit includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted,
When the prediction block adjacent to one of the sides is inter-predicted using the reference list to be derived, the value of the reference index information of the reference list to be derived of the prediction block adjacent to the one of the sides Is set in the reference index information of the derivation-target reference list of temporal merge candidates, and the prediction block adjacent to one of the sides is inter-predicted without using the derivation-target reference list, the time Set reference index information of the derivation reference list of merge candidates to a default value,
(Ii) When the prediction block adjacent to the one side is not inter-predicted, and the prediction block adjacent to the other side for the one side is inter-predicted,
When the prediction block adjacent to the other side is inter-predicted using the reference list for the derivation target, the value of the reference index information of the prediction block adjacent to the other side is set as the derivation target of the temporal merge candidate. When the prediction block adjacent to the other side is set to the reference index information of the reference list and is inter-predicted without using the derivation reference list, reference to the derivation target reference list of temporal merge candidates A moving picture coding apparatus, wherein index information is set to a default value. A moving image encoding device that encodes the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving unit derived as reference index information of
A temporal merge candidate generator for deriving inter prediction information of temporal merge candidates based on the derived reference index information,
The reference index deriving unit has a priority order that gives priority to either the prediction block adjacent to the left side of the prediction block to be encoded or the prediction block adjacent to the upper side of the prediction block to be encoded, The moving picture coding apparatus, wherein the reference index information value of the adjacent prediction block is set in the reference index information of the temporal merge candidate. A moving image encoding method for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
A temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information,
In the reference index derivation step, the smaller of the reference index information of the prediction block adjacent to the left side of the encoding target prediction block and the reference index information of the prediction block adjacent to the upper side of the encoding prediction block Is set as reference index information of temporal merge candidates. A moving image encoding method for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
A temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information,
The reference index derivation step includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted using a reference list to be derived, the prediction block is adjacent to the one side Set the value of the reference index information of the prediction block to the reference index information of the reference list of the derivation target of the temporal merge candidate,
(Ii) When a prediction block adjacent to one of the sides is not inter-predicted using the reference list to be derived, and adjacent to the other side with respect to the one of the sides When the prediction block is inter-predicted using the derivation reference list, the value of the reference index information of the prediction block adjacent to the other side is used as the reference index information of the derivation reference list of temporal merge candidates. A moving picture encoding method, comprising: setting. A moving image encoding method for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
A temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information,
The reference index derivation step includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted,
When the prediction block adjacent to one of the sides is inter-predicted using the reference list to be derived, the value of the reference index information of the reference list to be derived of the prediction block adjacent to the one of the sides Is set in the reference index information of the derivation-target reference list of temporal merge candidates, and the prediction block adjacent to one of the sides is inter-predicted without using the derivation-target reference list, the time Set reference index information of the derivation reference list of merge candidates to a default value,
(Ii) When the prediction block adjacent to the one side is not inter-predicted, and the prediction block adjacent to the other side for the one side is inter-predicted,
When the prediction block adjacent to the other side is inter-predicted using the reference list for the derivation target, the value of the reference index information of the prediction block adjacent to the other side is set as the derivation target of the temporal merge candidate. When the prediction block adjacent to the other side is set to the reference index information of the reference list and is inter-predicted without using the derivation reference list, reference to the derivation target reference list of temporal merge candidates A moving picture coding method, wherein index information is set to a default value. A moving image encoding method for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
A temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information,
The reference index derivation step is a priority order that gives priority to either the prediction block adjacent to the left side of the prediction block to be encoded or the prediction block adjacent to the upper side of the prediction block to be encoded. A moving picture coding method, wherein a value of reference index information of the adjacent prediction block is set as reference index information of a temporal merge candidate. A moving image encoding program for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
Causing the computer to perform a temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information;
In the reference index derivation step, the smaller of the reference index information of the prediction block adjacent to the left side of the encoding target prediction block and the reference index information of the prediction block adjacent to the upper side of the encoding prediction block Is set as the reference index information of the temporal merge candidate. A moving image encoding program for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
Causing the computer to perform a temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information;
The reference index derivation step includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted using a reference list to be derived, the prediction block is adjacent to the one side Set the value of the reference index information of the prediction block to the reference index information of the reference list of the derivation target of the temporal merge candidate,
(Ii) When a prediction block adjacent to one of the sides is not inter-predicted using the reference list to be derived, and adjacent to the other side with respect to the one of the sides When the prediction block is inter-predicted using the derivation reference list, the value of the reference index information of the prediction block adjacent to the other side is used as the reference index information of the derivation reference list of temporal merge candidates. A moving picture encoding program characterized by being set. A moving image encoding program for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
Causing the computer to perform a temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information;
The reference index derivation step includes:
(I) When a prediction block adjacent to one of the left side and the upper side of the prediction block to be encoded is inter-predicted,
When the prediction block adjacent to one of the sides is inter-predicted using the reference list to be derived, the value of the reference index information of the reference list to be derived of the prediction block adjacent to the one of the sides Is set in the reference index information of the derivation-target reference list of temporal merge candidates, and the prediction block adjacent to one of the sides is inter-predicted without using the derivation-target reference list, the time Set reference index information of the derivation reference list of merge candidates to a default value,
(Ii) When the prediction block adjacent to the one side is not inter-predicted, and the prediction block adjacent to the other side for the one side is inter-predicted,
When the prediction block adjacent to the other side is inter-predicted using the reference list for the derivation target, the value of the reference index information of the prediction block adjacent to the other side is set as the derivation target of the temporal merge candidate. When the prediction block adjacent to the other side is set to the reference index information of the reference list and is inter-predicted without using the derivation reference list, reference to the derivation target reference list of temporal merge candidates A moving picture coding program characterized by setting index information to a default value. A moving image encoding program for encoding the moving image using motion compensation in blocks obtained by dividing each picture of the moving image,
Inter prediction information that is a temporal merge candidate based on inter prediction information of a prediction block existing at the same position or in the vicinity of the prediction block to be encoded in a coded picture that is temporally different from the prediction block to be encoded In the merge mode in which inter prediction of the prediction block to be encoded is performed based on the derived inter prediction information, reference index information for specifying a reference picture used in the prediction block to be encoded is temporal merge candidate A reference index deriving step derived as reference index information of
Causing the computer to perform a temporal merge candidate generation step of deriving inter prediction information of the temporal merge candidate based on the derived reference index information;
The reference index derivation step is a priority order that gives priority to either the prediction block adjacent to the left side of the prediction block to be encoded or the prediction block adjacent to the upper side of the prediction block to be encoded. A moving picture coding program characterized in that a value of reference index information of the adjacent prediction block is set as reference index information of a temporal merge candidate.

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