JP2013102260A - Moving image decoder, moving image decoding method and moving image decoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that there is a case in which the number of candidates of motion information referred to for each block in motion compensation is fixed in a conventional case.SOLUTION: An inter-prediction information derivation section 205 derives a candidate of inter-prediction information including information on a motion vector and information on a reference picture from a prediction block adjacent to a prediction block of a decoding object or a prediction block present in the same position as the prediction block of the decoding object in a decoded picture, which temporally differs from the prediction block of the decoding object, or in the vicinity of the block. A merged candidate supplementing section 236 makes the motion vector of the candidate of the inter-prediction information in which a picture distance between a picture including the prediction block of the decoding object and the reference picture is one into integral multiple, generates a new candidate of the inter-prediction information and supplements it as the candidate of the inter-prediction information. A motion compensation prediction section 206 inter-predicts the prediction block of the decoding object by the candidate of the inter-prediction information, which is selected from the candidates of the inter-prediction information after supplementation.

Description

  The present invention relates to a moving picture decoding technique, and more particularly to a moving picture decoding 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 both inter predictions of L0 prediction and L1 prediction is also defined. In the case of bi-prediction, each inter-predicted signal of L0 prediction and L1 prediction is multiplied by a weighting coefficient, an offset value is added and superimposed, and a final inter-predicted image signal is generated. 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

  In the conventional method, since the number of motion information candidates to be referenced for each block in motion compensation is fixed, the encoding efficiency may not increase.

  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 scheme 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 obtain a moving picture decoding technique that improves encoding efficiency by reducing the amount of encoded information by calculating encoding information candidates. Is to provide.

  In order to solve the above problem, a moving picture decoding apparatus according to an aspect of the present invention decodes a coded bit string obtained by coding the moving picture using motion compensation prediction in units of blocks obtained by dividing each picture of the moving picture. A decoding block that is adjacent to the prediction block to be decoded or is present at the same position as or near the prediction block to be decoded in a decoded picture that is temporally different from the prediction block to be decoded A prediction information deriving unit (230, 231 and 232) for deriving a candidate of inter prediction information including motion vector information and reference picture information from the prediction block to be decoded, and the picture including the prediction block to be decoded and the reference Scale by multiplying motion vectors of inter prediction information candidates whose inter-picture distance is 1 by an integer. A candidate interpolating unit (236) for generating a new candidate for inter prediction information by calculation and supplementing it as a candidate for inter prediction information, and one inter prediction from the inter prediction information candidates after supplementing by the candidate supplementing unit A motion compensation prediction unit (206) that selects information candidates and performs inter prediction of the prediction block to be decoded based on the selected inter prediction information candidates.

  Another aspect of the present invention is also a video decoding device. This apparatus is a moving picture decoding apparatus that decodes a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture, and predicting a decoding target in a B slice From the prediction block adjacent to the block or the prediction block existing in the same position as or near the prediction block in the decoded picture temporally different from the prediction block to be decoded, the motion vector information and the reference picture A prediction information deriving unit (230, 231 and 232) for deriving bi-prediction inter prediction information candidates including information, and a picture-to-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction 1 for bi-prediction inter prediction information candidates, the motion vector of the first prediction is scaled to an integer multiple. A new bi-prediction inter prediction information candidate is generated by using the second prediction motion vector as the second prediction vector or the picture including the prediction block to be decoded and the second prediction In the bi-prediction inter prediction information candidate in which the inter-picture distance of the reference picture is 1, a value obtained by scaling the motion vector of the second prediction to an integral multiple is used as the motion vector of the first prediction, so that Candidate bi-prediction inter prediction information candidates are generated and supplemented as bi-prediction inter prediction information candidates, and the bi-prediction inter-prediction information candidates supplemented by the candidate replenishment unit One bi-prediction inter prediction information candidate is selected, and the decoding target prediction block is selected according to the selected bi-prediction inter prediction information candidate. Tsu comprising motion compensation prediction unit that performs inter prediction of bi-prediction of click and (206).

  Yet another embodiment of the present invention is also a moving picture decoding apparatus. This apparatus is a moving picture decoding apparatus that decodes a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture, and predicting a decoding target in a B slice From the prediction block adjacent to the block or the prediction block existing in the same position as or near the prediction block in the decoded picture temporally different from the prediction block to be decoded, the motion vector information and the reference picture A prediction information deriving unit (230, 231 and 232) for deriving bi-prediction inter prediction information candidates including information, and the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is 1 In the inter prediction information candidates other than bi-prediction, the motion vector of the first prediction is scaled by −1. A new bi-prediction inter prediction information candidate is generated by using the calculated motion vector for the other second prediction, or the picture including the prediction block to be decoded and the second prediction reference In a bi-prediction inter prediction information candidate having a picture inter-picture distance other than 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction by -1 times is used as a new prediction motion vector. A candidate supplementing unit (236) that generates prediction inter prediction information candidates and supplements them as bi-prediction inter prediction information candidates, and one candidate from the bi-prediction inter prediction information candidates after supplementation by the candidate supplementing unit. A candidate for inter prediction information for bi-prediction is selected, and the bi-prediction of the prediction block to be decoded is selected based on the selected candidate for inter-prediction information for bi-prediction. And a motion compensation prediction unit (206) for performing inter prediction.

  Yet another aspect of the present invention is a video decoding method. This method is a moving picture decoding method for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture, and is adjacent to the prediction block to be decoded. Motion vector information and reference picture information from a prediction block existing at or near the same position as the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded or the prediction block to be decoded A prediction information deriving step for deriving a candidate for inter prediction information, and by multiplying a motion vector of a candidate for inter prediction information whose inter-picture distance between the picture including the prediction block to be decoded and the reference picture is 1 by an integer Scaling operation is performed to generate new inter prediction information candidates. Candidate interpolating step to be supplemented as one inter prediction information candidate selected from the inter prediction information candidates after supplementing in the candidate supplementing step, and the decoding target prediction block based on the selected inter prediction information candidate A motion compensation prediction step for performing inter prediction.

  Yet another embodiment of the present invention is also a moving image decoding method. This method is a moving picture decoding method for decoding a coded bit sequence in which the moving picture is coded using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture, and predicting a decoding target in a B slice From the prediction block adjacent to the block or the prediction block existing in the same position as or near the prediction block in the decoded picture temporally different from the prediction block to be decoded, the motion vector information and the reference picture A prediction information deriving step for deriving bi-prediction inter prediction information candidates including information, and a bi-prediction inter-picture distance between a picture including the prediction block to be decoded and the reference picture of the first prediction is 1. In the prediction information candidate, the motion vector of the first prediction is scaled to an integral multiple. By generating a motion vector for the other second prediction, a new candidate for inter prediction information for bi-prediction is generated, or a picture including a prediction block to be decoded and a reference picture for the second prediction In a bi-prediction inter prediction information candidate having an inter-picture distance of 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction to an integer multiple is used as a first prediction motion vector, whereby a new bi-prediction inter prediction information is obtained. A candidate replenishment step for generating a prediction information candidate and replenishing it as a candidate for bi-prediction inter prediction information, and one inter-prediction information for bi-prediction from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate replenishment step And the bi-prediction event of the prediction block to be decoded is selected according to the selected bi-prediction inter prediction information candidate. And a motion compensated prediction step of performing ter prediction.

  Yet another embodiment of the present invention is also a moving image decoding method. This method is a moving picture decoding method for decoding a coded bit sequence in which the moving picture is coded using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture, and predicting a decoding target in a B slice From the prediction block adjacent to the block or the prediction block existing in the same position as or near the prediction block in the decoded picture temporally different from the prediction block to be decoded, the motion vector information and the reference picture A prediction information deriving step for deriving bi-prediction inter prediction information candidates including information, and a bi-prediction inter prediction in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is other than 1. An information candidate obtained by scaling the motion vector of the first prediction by -1 times By generating a motion vector for the second prediction of the other one, a new candidate for inter prediction information for bi-prediction is generated, or the inter-picture distance between the picture including the prediction block to be decoded and the reference picture for the second prediction In the bi-prediction inter prediction information candidates other than 1, the bi-prediction inter-prediction information obtained by scaling the second prediction motion vector to -1 is used as the first prediction motion vector. A candidate replenishment step for generating a candidate for inter prediction information for bi-prediction, and a candidate for inter-prediction information for bi-prediction from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate supplement step And the bi-prediction inter prediction of the prediction block to be decoded is performed according to the selected bi-prediction inter prediction information candidate. Cormorants and a motion compensated prediction step.

  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 prediction block unit 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 the merge candidate derivation | leading-out process of merge mode, and the construction process procedure of a merge candidate list | wrist. It is a flowchart explaining the space merge candidate derivation | leading-out process of merge mode. It is a flowchart explaining the derivation | leading-out process procedure of the reference index of the time merge candidate 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 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. It is a flowchart explaining a merge candidate replenishment (derivation / registration) processing procedure to a merge candidate list in a merge mode. FIG. 26 is a flowchart for describing a supplement processing procedure for scaling single prediction merge candidates whose slice type slice_type in FIG. 25 is an integer multiple of P slices. FIG. 27 is a flowchart for explaining a replenishment processing procedure for a scaling single prediction merge candidate in which a scaling operation process is performed by deriving a scale factor ScaleFactor that is an integer multiple of FIG. 26. FIG. 26 is a flowchart for describing a supplementary processing procedure for scaling bi-predictive merge candidates whose slice type slice_type in FIG. 25 is an integral multiple of B slices. FIG. 29 is a flowchart for describing a first scaling bi-predictive merge candidate replenishment processing procedure for deriving an integer multiple scale factor ScaleFactor of FIG. 28 and performing scaling calculation processing. FIG. 29 is a flowchart for explaining a second scaling bi-predictive merge candidate replenishment processing procedure for performing a scaling operation process as a scale factor ScaleFactor that is −1 times that of FIG. 28. 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, a slice obtained by dividing a picture into one or more is a basic unit of encoding, and a slice type, which is information indicating a slice type, is set for each slice. As shown in FIG. 3, the slice is equally divided into square units of any same size. This unit is defined as a tree block, and is a block to be encoded / decoded in a slice (a block to be encoded in the encoding process and a block to be decoded 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 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. Any two reference pictures can be selected for each prediction block and inter prediction can be performed, and there are L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI) as inter prediction modes. 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 for inter prediction with a slice type 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 for inter prediction with a slice type 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.

  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 header information setting unit 117, a motion vector detection unit 102, a differential motion vector calculation unit 103, an inter prediction information derivation unit 104, a motion compensation prediction unit 105, and an intra prediction unit. 106, prediction method determination unit 107, residual signal generation unit 108, orthogonal transform / quantization unit 109, first encoded bit sequence generation unit 118, second encoded bit sequence generation unit 110, third encoded bit sequence generation unit 111, A multiplexing unit 112, an inverse quantization / inverse orthogonal transform unit 113, a decoded image signal superimposing unit 114, an encoded information storage memory 115, and a decoded image memory 116 are provided.

  The header information setting unit 117 sets information in units of sequences, pictures, and slices. The set sequence, picture, and slice unit information is supplied to the inter prediction information deriving unit 104 and the first encoded bit string generating unit 118, and is also supplied to all blocks (not shown).

  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 and registered in a merge candidate list, which will be described later, using the encoding information of an already encoded prediction block stored in the encoding information storage memory 115, 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 116, 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 split mode PartMode are determined. In inter prediction (PRED_INTER), it is determined whether or not it is merge mode for each prediction block. Determines the merge index, and when not in the merge mode, the inter prediction mode, the prediction motion vector index, the reference index of L0 and L1, the difference motion vector, etc. are determined, and the encoded information corresponding to the determination is determined as the second encoded bit string generation unit 110. To supply.

  Further, 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 according to the quantization parameter to generate an orthogonal transform / quantized residual signal, and a third encoded bit string generation unit 111 And supplied to 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 118 encodes the sequence, picture, and slice unit information set by the header information setting unit 117. A first encoded bit string is generated and supplied to the multiplexing unit 112.

  The 2nd coding bit stream production | generation part 110 encodes the encoding information according to the prediction method determined by the prediction method determination part 107 for every encoding block and prediction block. 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 described later to generate a second encoded bit string, which is supplied to the multiplexing unit 112.

  The third encoded bit string generation unit 111 generates a third encoded bit string by entropy-encoding the orthogonally transformed and quantized residual signal according to a prescribed syntax rule, and supplies the third encoded bit string to the multiplexing unit 112. The multiplexing unit 112 multiplexes the first encoded bit string, the second encoded bit string, and the third encoded bit string in accordance with a specified 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 212, a second encoded bit string decoding unit 202, a third encoded bit string decoding unit 203, a motion vector calculation unit 204, and inter prediction information. A derivation unit 205, 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 are provided.

  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 a first encoded bit string decoding unit 212, a second encoded bit string decoding unit 202, and a third encoded bit string. The data is supplied to the decoding unit 203.

  The first encoded bit string decoding unit 212 decodes the supplied encoded bit string to obtain information in units of sequences, pictures, and slices. The information of the obtained sequence, picture, and slice unit is supplied to all blocks although not shown.

  The second encoded bit string decoding unit 202 decodes the supplied encoded bit string to obtain 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 third 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 derived and registered in a motion vector predictor list, which will be described later, and a second encoded bit string decoding unit out of the motion vector predictor candidates registered in the motion vector predictor list 202, a prediction motion vector corresponding to the prediction motion vector index decoded and supplied is selected, a motion vector is calculated from the difference vector decoded by the second 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. Using the encoded information of the already decoded prediction block stored in the encoded information storage memory 210, a plurality of merge candidates are derived and registered in a merge candidate list described later, and registered in the merge candidate list Whether a merge candidate corresponding to a merge index decoded and supplied by the second 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 second 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.

  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 syntax rules 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. When entropy encoding / decoding of a merge index is performed, the smaller the number of merge candidates is, the more encoding / decoding can be performed with a small code amount, and the encoding / decoding can be performed with a small amount of processing. FIG. 11 shows an example of the entropy code (code) of the merge index syntax element merge_idx [x0] [y0]. When the number of merge candidates is 3, when the merge index is 0, 1, 2, the codes of the merge index syntax elements merge_idx [x0] [y0] are “0”, “10”, and “11”, respectively. When the number of merge candidates is 4, when the merge index is 0, 1, 2, 3, the signs of the merge index syntax elements merge_idx [x0] [y0] are '0', '10', '110', It becomes '111'. When the number of merge candidates is 5, 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”, and “110”, respectively. ',' 1110 ', and' 1111 '. That is, when the number of merge candidates is different, the merge index can be expressed with a smaller code amount when the number of merge candidates is smaller. In this embodiment, as shown in FIG. 11, the code amount is reduced by switching the code indicating each value of the merge index based on the number of merge candidates set in slice units.

  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.

  The inter prediction information derivation method according to the embodiment is performed in any of 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, the prediction block Col (any one of T0 and T1) existing at or near the same position at different times described with reference to FIG. 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 second encoded bit string generation unit 110, and performs inter prediction information of the video decoding device. The derivation unit 205 is supplied with the merge index decoded by the second 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.

  Set the final number of merge candidates finalNumMergeCand registered in the merge candidate list mergeCandList in slice units. In the present embodiment, finalNumMVPCand is set to 5.

  An inter prediction information derivation method according to an embodiment will be described with reference to the drawings. FIG. 12 is a diagram illustrating a detailed configuration of the inter prediction information deriving unit 104 of the video encoding device in FIG. FIG. 13 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. 12 and 13 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 number limiting unit. 135, a merge candidate supplementing unit 136, and an encoding information selecting unit 137.

  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 number limiting unit. 235, a merge candidate supplementing unit 236, and an encoded information selecting unit 237.

FIG. 14 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 slice type slice_type is P slice and inter prediction is performed using inter prediction information of temporal merge candidates, in order to perform L0 prediction (Pred_L0), only the L0 reference index is derived, and the slice type slice_type is 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 number limiting unit 135 of the inter prediction information deriving unit 104 of the video encoding device and the merge candidate number limiting unit 235 of the inter prediction information deriving unit 205 of the video decoding device are registered in the merge candidate list mergeCandList. If the number of merge candidates registered in the merge candidate list mergeCandList is greater than the final merge candidate number finalNumMergeCand (YES in step S106), the index i in the merge candidate list mergeCandList is counted. The merge candidates are limited to the final merge candidate number finalNumMergeCand by deleting all merge candidates that are greater than (finalNumMergeCand-1), and the value of the merge candidate number numMergeCand registered in the merge candidate list mergeCandList is set as the final merge candidate The number is updated to finalNumMergeCand (step S107).

  Subsequently, the merge candidate supplementing unit 136 of the inter prediction information deriving unit 104 of the video encoding device and the merge candidate supplementing unit 236 of the inter prediction information deriving unit 205 of the video decoding device are registered in the merge candidate list mergeCandList. If the number of merge candidates numMergeCand is smaller than the final merge candidate number finalNumMergeCand (YES in step S108), the merge candidate number numMergeCand registered in the merge candidate list mergeCandList is replenished with merge candidates up to the final merge candidate number finalNumMergeCand ( (Derivation / registration) (step S109). With the final merge candidate number finalNumMergeCand as the upper limit, in the P slice, the inter prediction mode derived by scaling the motion vector by an integer multiple based on the merge candidates already registered in the merge candidate list mergeCandList is single prediction. A merge candidate for L0 prediction (Pred_L0) is added. In B slice, inter prediction mode derived by scaling one motion vector by integer multiple based on merge candidates already registered in merge candidate list mergeCandList added bi-prediction (Pred_BI) merge candidates To do. The detailed processing procedure of step S109 will be described later in detail using the flowchart of FIG.

  In the present embodiment, the final candidate number finalNumMVPCand is set to a fixed number for each slice. The reason for fixing the final candidate number finalNumMVPCand is that if the final candidate number finalNumMVPCand fluctuates according to the construction state of the merge candidate list, a dependency relationship occurs between the entropy decoding and the merge candidate list construction, and the decoding candidate merge candidate list for each prediction block This is because the merge index cannot be entropy decoded unless the final candidate number finalNumMVPCand is derived and the merge index is delayed and the entropy decoding becomes complicated. Furthermore, if entropy decoding depends on the construction state of the merge candidate list including the merge candidate Col derived from the prediction block of the picture at different times, the current picture when an error occurs when decoding the encoded bit string of another picture The encoded bit string of the above is also affected by the error, so that the normal final candidate number finalNumMVPCand cannot be derived and the entropy decoding cannot be continued normally. When the final candidate number finalNumMVPCand is set to a fixed number in slice units as in this embodiment, derivation of the final candidate number finalNumMVPCand in prediction block units becomes unnecessary, and the merge index is set independently of the merge candidate list construction. Entropy decoding can be performed, and entropy decoding of the encoded bit string of the current picture can be continued without being affected by an error even when an encoded bit string of another picture is decoded.

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. 14, will be described in detail. FIG. 15 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, the upper limit value maxNumSpatialMergeCand of the number of spatial merge candidates is set to 4, and 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 total number of spatial merge candidates that can be derived so far (availableFlag is 1) is the upper limit value maxNumSpatialMergeCand of the number of spatial merge candidates (YES in step S1102), that is, when four spatial merge candidates are derived 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 flag predFlagL0N of the merge candidate N is set. Both values of predFlagL1N are set to 0 (step S1107), and this 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, when the sum of spatial merge candidates that can be derived so far (availableFlag is 1) is not the upper limit value maxNumSpatialMergeCand of the number of spatial merge candidates (NO in step S1102), it is adjacent to the prediction block to be encoded / decoded. The prediction block N is specified, and when each prediction block N can be used, 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. 14 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.

  In the present embodiment, both the prediction block A and the prediction block B are LX predictions (L0 or L1, the list from which reference indexes of temporal merge candidates are derived is LX, and prediction using LX is LX prediction. In this case, the smaller LX reference index value of the prediction block A and the prediction block B is adopted as the LX reference index value of the temporal merge candidate. 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 in sequence units, picture units, or slice units. The syntax element shown may be installed and transmitted so that it can be selected on the encoding side.

FIG. 16 is a flow chart for explaining the procedure for deriving the reference index of the time merge candidate in step S102 of FIG. 14 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, the method for deriving merge candidates at different times in S103 of FIG. 14 will be described in detail. FIG. 17 is a flowchart illustrating the time merge candidate derivation processing procedure in step S103 of FIG.

  First, as shown in an example of a syntax rule that is a common rule for encoding and decoding a bitstream in FIG. 26, a slice type slice_type described in a slice header in units of slices and a candidate for a predicted motion vector in the time direction, or Flag collocated_from_l0_flag indicating whether a picture colPic at a different time used when deriving merge candidates uses a reference picture registered in the L0 reference list or the L1 reference list of the picture including the prediction block to be processed Thus, pictures colPic at different times are derived (step S3101).

  FIG. 18 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 flag collocated_from_l0_flag is 0 (YES in step S3201 and YES in step S3202), RefPicList1 [0], that is, the picture colPic of the reference list L1 with a reference index of 0 is a different time. (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. 17, a prediction block colPU at a different time is derived, and encoded information is acquired (step S3102).

  FIG. 19 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 in 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. 17, 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. 20 is a flowchart for explaining the process of deriving inter prediction information of the temporal merge candidate in step S3103 and step 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. 20), 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. 21 is a flowchart showing 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). 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. 20, 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). The motion vector scaling calculation processing procedure will be described with reference to FIGS.

  FIG. 22 is a flowchart showing the motion vector scaling calculation processing procedure in step S3415 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 is 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 reference index of the temporal merge candidate LX derived in step S102 of FIG. 14 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 scale factor tb / td according to the following equation (step S3605), and the scaled temporal merge candidate Obtain the motion vector mvLXCol of LX.
mvLXCol = tb / td * mvCol

  FIG. 23 shows an example of the case where the scaling operation in step S3605 is performed with integer precision arithmetic. The processing from step S3606 to step S3608 in FIG. 23 corresponds to the processing in step S3605 in FIG.

  First, as in the flowchart of FIG. 22, 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), the LX motion vector mvLXCol as a temporal merge candidate is obtained, 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 scale coefficient DistScaleFactor is derived from the following equation (step S3607).
DistScaleFactor = (tb * tx + 32) >> 6

Subsequently, the LX motion vector mvLXCol of the scaled temporal merge candidate 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. 14 in the merge candidate list will be described in detail. FIG. 24 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. 12, the encoding information selection unit 137 of the inter prediction information deriving unit 104 of the moving image encoding apparatus selects merge candidates from the merge candidates registered in the merge candidate list, and merge indexes and merge indexes. 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. 13, the encoding information selection unit 237 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.

  Next, a method for supplementing (derivation / registration) of merge candidates in step S109 in FIG. 14 will be described in detail. FIG. 25 is a flowchart showing a merge candidate supplement processing procedure. A new merge candidate is generated based on the merge candidates already registered in the merge candidate list mergeCandList up to the set final merge candidate number finalNumMergeCand and added to the merge candidate list to replenish the merge candidate number. The code amount is reduced by widening the selection range of merge candidates.

  When the slice type slice_type is a P slice (YES in step S5101), an integer multiple scale factor is derived, and an inter prediction mode is supplemented (derived / registered) with a scaling single prediction merge candidate having an integer multiple of L0 prediction (Pred_L0). (Step S5103). When the slice type slice_type is a B slice (NO in step S5101, YES in step S5102), an integer multiple scale factor is derived, and inter-prediction modes are supplemented with scaling bi-prediction merge candidates with an integer multiple of bi-prediction (Pred_BI) ( (Derivation / registration) (step S5104).

  Next, a method for supplementing (derivation / registration) of scaling single prediction merge candidates in which the slice type slice_type of S5103 in FIG. 25 is an integer multiple of P slices will be described in detail. FIG. 26 is a flowchart for explaining a supplement processing procedure for scaling single prediction merge candidates in which the slice type slice_type in step S5103 in FIG.

  First, it is determined whether or not the number of reference pictures of the reference picture RefPicListL0 of L0 is larger than 1. If the number of reference pictures is 1 or less (NO in step S5201), the scaling single prediction merge candidate supplement processing procedure of FIG. finish. On the other hand, if the number of reference pictures is greater than 1 (YES in step S5201), the merge index i of the merge candidate list and the variable numScaledCand indicating the number of scaled merge candidates are initialized to 0 and registered in the merge candidate list so far The first merge candidate number numFirstMergeCand, which is a variable indicating the number of merge candidates, is set to the value of the current merge candidate number numMergeCand (step S5202). Subsequently, the iterative process after step S5203 is performed. If the current merge candidate number numMergeCand is smaller than the final merge candidate number finalNumMergeCand (YES in step S5204), the processing from step S5205 is performed, and if the current merge candidate number numMergeCand is greater than or equal to the final merge candidate number finalNumMergeCand (step S5204). NO), the scaling single prediction merge candidate supplement processing procedure of FIG. 26 is terminated. Next, when the scaled merge candidate number numScaledCand is smaller than the specified maximum scaling merge candidate derivation processing number maxNumScaledCand (YES in S5205), the processing after step S5206 is performed, and the scaled merge candidate number numScaledCand is defined. When the maximum scaling merge candidate derivation processing count maxNumScaledCand is greater than or equal to (NO in S5205), the scaling single prediction merge candidate supplement processing procedure in FIG. Increasing the maximum scaling merge candidate derivation processing number maxNumScaledCand increases the number of arithmetic processings, but increases the selection range of merge candidates and improves the coding efficiency. For example, when the value of the final merge candidate number finalNumMergeCand is 5, the value of the merge candidate derivation processing number maxNumScaledCand may be defined to be about 1 to 3.

  Next, the inter-picture derived by subtracting the POC of the reference picture of the L0 prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. If the distance value is 1 (YES in step S5206), the scaling single prediction merge candidate supplement process of FIG. 27 is performed (step S5207). If the inter-picture distance value is not 1 (NO in step S5206), FIG. The process after step S5208 is performed without performing the scaling single prediction merge candidate supplement process. In the present embodiment, when the slice type slice_type is P slice, the L0 prediction of the L0 prediction referred to by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. Only when the inter-picture distance value derived by subtracting the POC of the reference picture is 1, a supplementary process of scaling single prediction merge candidates for deriving an integer multiple scale factor ScaleFactor is performed. In this way, the picture derived by subtracting the POC of the L0 prediction reference picture referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. By supplementing scaling single prediction merge candidates only when the value of the inter-distance is 1, simplification of the derivation process of the scale factor ScaleFactor, excluding the scaling calculation process including division with a large amount of calculation, The scaling calculation process is performed only by multiplication with a smaller calculation amount.

  FIG. 27 is a flowchart for explaining a scaling single prediction merge candidate replenishment processing procedure for deriving an integer multiple scale factor ScaleFactor in step S5207 in FIG. 26 and performing scaling calculation processing. The L0 motion vector is derived from the L0 motion vectors of the merge candidates already registered in the merge candidate list by a scaling operation process by integer multiples, and set as a single prediction merge candidate.

  First, the L0 reference index refIdxL0Scaled of the scaling single prediction merge candidate is changed to an index value with a high occurrence probability different from the L0 reference index refIdxL0 of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list. Setting is performed (steps S5301 to S5303). When the L0 reference index refIdxL0 of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list is the first default value 0 (YES in step S5301), the scaling single prediction merge candidate L0 The reference index refIdxL0Scaled is set to the second default value 1 (step S5302), and the reference index refIdxL0 of L0 of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list is the first default value. If it is not 0 (NO in step S5301), the reference index refIdxL0Scaled of L0 of the scaling single prediction merge candidate is set to the first default value 0 (step S5303). The first default value is defined as the value of the reference index having the highest probability of occurrence, and the second default value is defined as the value of the reference index having the second highest probability of occurrence. In the present embodiment, the first default value is defined as 0 on the assumption that the reference index with the highest occurrence probability is 0, and the second default is assumed on the assumption that the reference index with the second highest occurrence probability is 1. The value is defined as 1. However, the present invention is not limited to this, and the first and second default values of the reference index may be different values, and the first and second reference indices may be included in the encoded stream at the sequence level, the picture level, or the slice level. A syntax element indicating a default value of 2 may be installed and transmitted so that it can be selected on the encoding side.

Subsequently, according to the following equation, the scale coefficient ScaleFactor is set to the value of the inter-picture distance derived by subtracting the POC of the reference picture corresponding to the reference index refIdxL0Scaled of L0 from the POC of the current picture (step S5304). ).
ScaleFactor = POC of the reference picture corresponding to the POC-L0 reference index refIdxL0Scaled of the current picture

  Note that the inter-picture distance and the scale factor ScaleFactor are not limited to positive values but may be negative values.

  In the present embodiment, in step S5206 of FIG. 26, the reference picture of the L0 prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. Only when the inter-picture distance value derived by subtracting the POC is 1, the scaling uni-predictive merge candidate is replenished. Therefore, the scale factor ScaleFactor is calculated from the POC of the current picture as L0. Can be set to the value of the inter-picture distance derived by subtracting the POC of the reference picture corresponding to the reference index refIdxL0Scaled, and the scale factor ScaleFactor derivation process can be simplified. Furthermore, the scale factor ScaleFactor is an integer, and an integer multiple scaling operation process can be performed without a large division.

Subsequently, scaling operation processing is performed by multiplying the L0 motion vector mvL0 of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list by the following equation by the scale factor ScaleFactor, and the scaled single prediction The L0 motion vector mvL0Scaled of the merge candidate is derived (step S5305).
mvL0Scaled = ScaleFactor * mergeCandList [i] L0 motion vector mvL0

  Subsequently, the flag predFlagL0Scaled is set to 1 and the flag predFlagL1Scaled is set to 0 (step S5306).

  Subsequently, the scaled number of single prediction merge candidates numScaledCand adds 1 to maxNumScaledCand (step S5307).

  Subsequently, all merge candidates registered in the merge candidate list mergeCandList are compared with the derived scaling single prediction merge candidates (step S5308). If the same merge candidate as the scaling single prediction merge candidate derived in the merge candidate list does not exist (YES in step S5309), the scaling single prediction merge candidate derived at the end of the merge candidate list mergeCandList is registered (step S5310). Then, 1 is added to the current number of merge candidates numMergeCand (step S5311), and the scaling single prediction merge candidate supplement process of FIG. 27 is terminated. When the same merge candidate as the scaling single prediction merge candidate derived in the merge candidate list exists (NO in step S5309), the scaling single prediction merge candidate derived in FIG. 27 is not registered in the merge candidate list. The single prediction merge candidate supplement process is terminated.

  Returning again to FIG. 26, 1 is added to the index i (step S5208).

  When the index i is smaller than the first merge candidate number numFirstMergeCand, the processing from step S5204 to step S5208 is repeated (steps S5203 to S5209), and when the condition is not satisfied, the scaling single prediction merge candidate supplement processing in FIG. To do.

  Next, a method for supplementing (derivation / registration) of scaling bi-predictive merge candidates with the slice type slice_type of B slice in S5104 in FIG. 25 will be described in detail. FIG. 28 is a flowchart for explaining the replenishment processing procedure for scaling bi-predictive merge candidates in which the slice type slice_type in step S5104 in FIG.

  First, the index i of the merge candidate list and the variable numScaledCand indicating the number of scaled merge candidates are initialized to 0, and the first merge candidate number numFirstMergeCand, which is a variable indicating the number of merge candidates registered in the merge candidate list so far, is set. The current number of merge candidates is set to the value of numMergeCand (step S5401). Subsequently, iterative processing after step S5402 is performed. Variable j is initialized to 0 (step S5403). Subsequently, iterative processing from step S5404 is performed. When the current merge candidate number numMergeCand is smaller than the final merge candidate number finalNumMergeCand (YES in step S5405), the processing from step S5406 is performed, and when the current merge candidate number numMergeCand is greater than or equal to the final merge candidate number finalNumMergeCand (step S5405). NO), the scaling bi-predictive merge candidate supplement processing procedure in FIG. 28 ends. Next, when the number of scaled merge candidates numScaledCand is smaller than the specified maximum scaling merge candidate derivation processing count maxNumScaledCand (YES in S5406), the processing after step S5407 is performed to define the scaled merge candidate number numScaledCand. If the maximum scaling merge candidate derivation processing count maxNumScaledCand is greater than or equal to (NO in S5406), the scaling bi-predictive merge candidate supplement processing procedure in FIG. 28 ends. Next, when the variable j is 0 (YES in step S5407), LX is L0 and LY is L1 (step S5408), and when the variable j is 1 (NO in step S5407), LX is L1 and LY is L0 is set (step S5409). Subsequently, when the LX prediction is performed with the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list (YES in step S5410), the scaling bi-predictive merge candidate supplement process after step S5411 is performed. When LX prediction is not performed on the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list (NO in step S5410), the scaling bi-predictive merge candidate supplement process from step S5411 to step S5413 is not performed. Then, the processing after step S5414 is performed.

  Next, an inter-picture derived by subtracting the POC of the reference picture of the LX prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture When the distance value is 1 (YES in step S5411), the first scaling bi-predictive merge candidate supplement process of FIG. 29 is performed (step S5412), and the merge candidate indicated by the index i registered in the merge candidate list is performed. When the inter-picture distance value derived by subtracting the POC of the reference picture of the LX prediction referenced by mergeCandList [i] is not 1 (NO in step S5411), the second scaling bi-predictive merge candidate in FIG. The replenishment process is performed (step S5413). In the present embodiment, when the slice type slice_type is B slice, the L0 prediction of the L0 prediction referred to by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. When the inter-picture distance value derived by subtracting the POC of the reference picture is 1, a scale factor ScaleFactor that is an integer multiple is derived, and a scaling operation process is performed. The first scaling bi-predictive merge candidate supplement process is performed. . Further, the inter-picture distance derived by subtracting the POC of the reference picture of the L0 prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. When the value of is not 1, the reference picture of the inter-frame distance corresponding to −1 is selected as the scale factor ScaleFactor of −1, and the supplement processing of the second scaling bi-predictive merge candidate for performing the scaling operation processing is performed. . In this way, the picture derived by subtracting the POC of the L0 prediction reference picture referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. The scale factor ScaleFactor is calculated only when the inter-distance value is 1, and when the derived inter-picture distance value is not 1, the scale factor ScaleFactor is set to -1, and the inter-frame distance corresponding to -1 is referred. By selecting a picture, the derivation process of the scale coefficient ScaleFactor is simplified, and the scaling calculation process including the division with a large calculation amount is excluded, and the scaling calculation process by only the multiplication with the small calculation amount compared with the division is performed.

  FIG. 29 is a flowchart for explaining the first scaling bi-predictive merge candidate supplement processing procedure for deriving an integer multiple scale factor ScaleFactor in step S5412 of FIG. 28 and performing scaling calculation processing. A bi-predictive merge candidate that uses these two motion vectors by deriving the other motion vector from one of the motion vectors L0 or L1 of the merge candidates already registered in the merge candidate list by a scaling operation by integer multiples; To do.

  First, the reference index k of LY is initialized to 0 (step S5501). Subsequently, the iterative process after step S5502 is performed. When the POC of the reference picture for LX prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list is different from the POC of the reference picture RefPicListLY [k] corresponding to the LY reference index k (YES in step S5503-1), scaling calculation processing by integer multiples after step S5504-1 is performed, and the LX prediction referred to by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list When the POC of the reference picture RefPicListLY [k] corresponding to the reference picture POC and the LY reference index k is the same (NO in step S5503-1), the process after step S5504-1 is not performed, and the reference index k is set to 1. Are added (S5513). If the reference index k is smaller than the LY reference index number numRefIdxLY (steps S5502 to S5514), the condition determination in step S5503-1 is performed again (step S5503-1), and the reference index k reaches the LY reference index number numRefIdxLY. In such a case, the first scaling bi-predictive merge candidate supplement process in FIG. 29 ends. However, in the first scaling bi-predictive merge candidate replenishment processing procedure of FIG. 29, the same reference picture is not registered in the LY reference list RefPicListLY, so the condition of step S5503-1 is two or more times. There is no NO, and the repeating process from step S5502 to S5514 is not repeated three times or more.

If YES in step S5503-1, the picture derived by subtracting the POC of the reference picture RefPicListLY [k] corresponding to the reference index k of LY from the POC of the current picture from the POC of the current picture according to the following equation: The distance value is set (step S5504-1).
ScalingFactor = POC of the reference picture RefPicListLY [k] corresponding to the POC-LY reference index k of the current picture

  Note that the inter-picture distance and the scale factor ScaleFactor are not limited to positive values but may be negative values.

  In the present embodiment, in step S5411 of FIG. 28, the reference picture of the LX prediction referenced by the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. Since the supplementary processing of the first scaling bi-predictive merge candidate is performed only when the inter-picture distance value derived by subtracting the POC is 1, the scale coefficient ScaleFactor is set to the POC of the current picture. Can be set to the value of the inter-picture distance derived by subtracting the POC of the reference picture RefPicListLY [k] corresponding to the reference index k of LY, and the scale factor ScaleFactor derivation process can be simplified. . Furthermore, the scale factor ScaleFactor is an integer, and an integer multiple scaling operation process can be performed without a large division.

Subsequently, the scaled bi-predictive merge candidate LX motion vector mvLXScaled is set to the value of the LX motion vector mvLX of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list. The scaling operation processing is performed by multiplying the LX motion vector mvLX of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list by the scale factor ScaleFactor, and the scaled bi-predictive merge candidate LY A motion vector mvLYScaled is derived (step S5505).
mvLXScaled = LX motion vector mvLX of mergeCandList [i]
mvLYScaled = ScaleFactor * LX motion vector mvLX of mergeCandList [i]

  Subsequently, the scaled bi-predictive merge candidate LX reference index refIdxLXScaled is set to the value of the LX reference index refIdxLX of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list. The bi-predictive merge candidate LY reference index refIdxLYScaled is set to the value of the reference index k (step S5506).

  Subsequently, both the flag predFlagL0Scaled and the flag predFlagL1Scaled are set to 1 (step S5507).

  Subsequently, the scaled merge candidate number numScaledCand adds 1 to maxNumScaledCand (step S5508).

  Subsequently, all merge candidates registered in the merge candidate list mergeCandList are compared with the derived scaled bi-predictive merge candidates (step S5509). If the same merge candidate as the scaling bi-predictive merge candidate derived in the merge candidate list does not exist (YES in step S5510), the derived scaling bi-predictive merge candidate is registered in the merge candidate list (step S5511). 1 is added to the number of merge candidates numMergeCand (step S5512), and the scaling bi-predictive merge candidate supplement process in FIG. 29 is terminated. When the same merge candidate as the scaling bi-predictive merge candidate derived in the merge candidate list exists (NO in step S5510), the derived scaling bi-predictive merge candidate is not registered in the merge candidate list, and the scaling of FIG. The bi-predictive merge candidate supplement process is terminated.

  Next, the replenishment processing procedure for the second scaling bi-predictive merge candidate in step S5413 in FIG. 28 will be described. FIG. 30 is a flowchart for explaining a second scaling bi-predictive merge candidate replenishment processing procedure in which the scaling calculation processing is performed as the scale factor ScaleFactor of −1 times of step S5413 in FIG. A bi-predictive merge candidate that uses the two motion vectors by deriving the other motion vector from a motion vector of one of the merge candidates L0 or L1 already registered in the merge candidate list by a scaling operation by −1 And The second scaling bi-predictive merge candidate supplement processing procedure of FIG. 30 is different from the first scaling bi-predictive merge candidate supplement processing procedure of FIG. 29 in that step 5503-1 and step 5504-1 are step S550-2 and step S5502, respectively. Step 5504-2 is different, and the processing of the other steps is the same. Therefore, only step S5502-2 and step 5504-2, which are different from the first scaling bi-predictive merge candidate supplement processing procedure of FIG. 29, will be described.

  The inter-picture distance obtained by subtracting the POC of the reference picture of the LX prediction of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture, and the reference of LY from the POC of the current picture When the magnitude (absolute value) of the inter-picture distance obtained by subtracting the POC of the reference picture RefPicListLY [k] corresponding to the index k is the same and the sign of the sign is different (YES in step S5502-2), step S5504-2 Subsequent scaling calculation processing by −1 is performed, and otherwise (NO in step S5503-2), processing in step S5513 and subsequent steps is performed.

  If YES in step S5503-2, the scale coefficient ScaleFactor is set to −1 (step S5504-2).

  In this embodiment, in step S5502-2 of FIG. 30, the POC of the reference picture for LX prediction of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list from the POC of the current picture. The subtracted inter-picture distance and the inter-picture distance obtained by subtracting the POC of the reference picture RefPicListLY [k] corresponding to the reference index k of LY from the POC of the current picture have the same sign. Are determined, the LY reference index k satisfying the condition is determined, and the scale factor ScaleFactor derivation process is simplified by setting the scale factor ScaleFactor to -1. Furthermore, since the scale factor ScaleFactor is −1, it is possible to perform scaling calculation processing that does not involve division with a large calculation amount.

  The subsequent processing from step S5505 is the same as in FIG. However, since the scale factor ScaleFactor is −1 in step S5505, the scale factor ScaleFactor −1 is added to the LX motion vector mvLX of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list. By multiplying, instead of deriving the LY motion vector mvLYScaled of the scaled bi-predictive merge candidate, the LX motion vector mvLX of the merge candidate mergeCandList [i] indicated by the index i registered in the merge candidate list The LY motion vector mvLYScaled of the bi-predictive merge candidate scaled to a value obtained by inverting the positive / negative sign may be set.

Returning again to FIG. 28, 1 is added to the variable j (step S5414).
When the variable j is smaller than 2, the processing from step S5405 to step S5414 is repeated (steps S5404 to S5415).

  After the repetition processing of steps S5404 to S5415 is completed, 1 is added to the index i (step S5416).

  When the index i is smaller than the first merge candidate number numFirstMergeCand, the processing from step S5403 to step S5416 is repeated (steps S5402 to S5417), and when the condition is not satisfied, the scaling bi-predictive merge candidate supplement processing procedure of FIG. finish.

  In the present embodiment, the scaling bi-predictive merge candidate supplement process in FIG. 28 uses both the first scaling bi-predictive merge candidate supplement process in step S5412 and the second scaling bi-predictive merge candidate supplement process in S5413. However, it may be configured to use only one of them.

  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, 117 Header information setting part, 102 Motion vector detection part, 103 Differential 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 unit, 109 orthogonal transform / quantization unit, 118 first encoded bit string generation unit, 110 second encoded bit string generation unit, 111 third encoded bit string generation unit, 112 multiplexing unit, 113 inverse quantization / inverse Orthogonal transform unit, 114 decoded image signal superimposing unit, 115 encoded information storage memory, 116 decoded image memory, 130 spatial merge candidate generating unit, 131 time merge candidate reference index deriving unit, 132 time merge candidate generating unit, 133 merge candidate Registration part, 134 merge candidate same size Fixed unit, 135 merge candidate number limiting unit, 136 merge candidate supplementing unit, 137 encoded information selecting unit, 201 separating unit, 212 first encoded bit sequence decoding unit, 202 second encoded bit sequence decoding unit, 203 third encoding Bit sequence decoding unit, 204 motion vector calculation unit, 205 inter prediction information deriving unit, 206 motion compensation prediction unit, 207 intra prediction unit, 208 inverse quantization / inverse orthogonal transform unit, 209 decoded image signal superimposing unit, 210 encoding information storage Memory, 211 decoded image memory, 230 spatial merge candidate generating unit, 231 time merge candidate reference index deriving unit, 232 time merge candidate generating unit, 233 merge candidate registering unit, 234 merge candidate identical determining unit, 235 merge candidate number limiting unit 236 Merge candidate supplement section 237 Encoding information selection unit.

Claims (12)

A moving picture decoding apparatus for decoding a coded bit string obtained by coding the moving picture using motion compensation prediction in units of blocks obtained by dividing each picture of the moving picture,
Motion vector information from a prediction block adjacent to a decoding target prediction block, or a prediction block existing in the same position as or near the decoding target prediction block in a decoded picture temporally different from the prediction target decoding block And a prediction information deriving unit for deriving a candidate of inter prediction information including information on the reference picture,
A new inter prediction information candidate is generated by performing a scaling operation by multiplying a motion vector of an inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture is 1, by integer multiplication A candidate supplementing unit that supplements the candidate as inter prediction information candidates;
Motion compensated prediction in which one inter prediction information candidate is selected from the inter prediction information candidates after being supplemented by the candidate supplementing unit, and inter prediction of the prediction block to be decoded is performed based on the selected inter prediction information candidate A moving picture decoding apparatus. The candidate supplement part is
When the reference index of the reference picture in the inter prediction information candidate whose inter-picture distance is 1 is the first specified value, the reference index of the reference picture in the new inter prediction information candidate is set to the second specified value. Set,
When the reference index of the reference picture in the inter prediction information candidate whose inter-picture distance is 1 is not the first specified value, the reference index of the reference picture in the new inter prediction information candidate is set to the first specified value The moving picture decoding apparatus according to claim 1, wherein: A moving picture decoding apparatus for decoding a coded bit string obtained by coding the moving picture using motion compensation prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving unit for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is 1, and the motion vector of the first prediction is scaled to an integral multiple Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or the picture including the prediction block to be decoded and the reference picture of the second prediction In a candidate for bi-prediction inter prediction information having a inter-picture distance of 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction to an integral multiple is used as the first prediction motion vector, thereby generating a new bi-prediction motion vector. A candidate supplementing unit that generates inter prediction information candidates and supplements them as bi-prediction inter prediction information candidates;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after being supplemented by the candidate supplement unit, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. A motion decoding apparatus comprising: a motion compensation prediction unit that performs inter prediction of block bi-prediction. The candidate supplement part is
A bi-prediction inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is 1, and the motion vector of the first prediction is scaled to an integral multiple Is used as the motion vector of the second prediction, the reference index of the reference picture of the second prediction is checked in order from 0 and set to a reference index that matches the motion vector of the second prediction that has been scaled to an integral multiple. ,
The motion vector of the second prediction is scaled to an integer multiple in a bi-prediction inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the second prediction is 1. When the motion vector of the first prediction is used, the reference index of the reference picture of the first prediction is checked in order from 0 and set to the reference index that matches the motion vector of the first prediction scaled to an integer multiple. The moving picture decoding apparatus according to claim 3, wherein: A moving picture decoding apparatus for decoding a coded bit string obtained by coding the moving picture using motion compensation prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving unit for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate having an inter-picture distance between the picture including the prediction block to be decoded and the first prediction reference picture other than 1, and the motion vector of the first prediction is scaled by −1 Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or a picture including a prediction block to be decoded and a picture of a second prediction reference picture In a candidate for bi-prediction inter prediction information having an inter-distance other than 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction by −1 times is used as a first prediction motion vector, whereby a new bi-prediction inter prediction information is obtained. A candidate supplementing unit that generates prediction information candidates and supplements them as candidates for bi-prediction inter prediction information;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after being supplemented by the candidate supplement unit, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. A motion decoding apparatus comprising: a motion compensation prediction unit that performs inter prediction of block bi-prediction. The candidate supplement part is
A bi-prediction inter prediction information candidate having an inter-picture distance between the picture including the prediction block to be decoded and the first prediction reference picture other than 1, and the motion vector of the first prediction is scaled by −1 Is used as the motion vector of the second prediction, the reference index of the reference picture of the second prediction is checked in order from 0 and set to a reference index that matches the motion vector of the second prediction that has been scaled by −1. And
A candidate for bi-prediction inter prediction information in which the inter-picture distance between the picture including the prediction block to be decoded and the second prediction reference picture is other than 1, and the motion vector of the second prediction is scaled by −1 Is used as the motion vector of the first prediction, the reference index of the reference picture of the first prediction is examined in order from 0 and set to the reference index that matches the motion vector of the first prediction that has been scaled by −1. The moving picture decoding apparatus according to claim 5, wherein: A moving picture decoding method for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
Motion vector information from a prediction block adjacent to a decoding target prediction block, or a prediction block existing in the same position as or near the decoding target prediction block in a decoded picture temporally different from the prediction target decoding block And a prediction information deriving step for deriving a candidate of inter prediction information including the information of the reference picture,
A new inter prediction information candidate is generated by performing a scaling operation by multiplying a motion vector of an inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture is 1, by integer multiplication A candidate replenishment step for replenishing as candidates for inter prediction information;
Motion compensated prediction in which one inter prediction information candidate is selected from the inter prediction information candidates after supplementation in the candidate supplementation step, and the prediction block to be decoded is inter-predicted by the selected inter prediction information candidate A moving picture decoding method comprising the steps of: A moving picture decoding method for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving step for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is 1, and the motion vector of the first prediction is scaled to an integral multiple Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or the picture including the prediction block to be decoded and the reference picture of the second prediction In a candidate for bi-prediction inter prediction information having a inter-picture distance of 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction to an integral multiple is used as the first prediction motion vector, thereby generating a new bi-prediction motion vector. A candidate replenishment step of generating candidates for inter prediction information and replenishing them as candidates for bi prediction inter prediction information;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate supplementation step, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. And a motion compensation prediction step for performing inter prediction of bi-prediction of blocks. A moving picture decoding method for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving step for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate having an inter-picture distance between the picture including the prediction block to be decoded and the first prediction reference picture other than 1, and the motion vector of the first prediction is scaled by −1 Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or a picture including a prediction block to be decoded and a picture of a second prediction reference picture In a candidate for bi-prediction inter prediction information having an inter-distance other than 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction by −1 times is used as a first prediction motion vector, whereby a new bi-prediction inter prediction information is obtained. A candidate replenishment step of generating prediction information candidates and replenishing them as bi-prediction inter prediction information candidates;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate supplementation step, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. And a motion compensation prediction step for performing inter prediction of bi-prediction of blocks. A moving picture decoding program for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
Motion vector information from a prediction block adjacent to a decoding target prediction block, or a prediction block existing in the same position as or near the decoding target prediction block in a decoded picture temporally different from the prediction target decoding block And a prediction information deriving step for deriving a candidate of inter prediction information including the information of the reference picture,
A new inter prediction information candidate is generated by performing a scaling operation by multiplying a motion vector of an inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture is 1, by integer multiplication A candidate replenishment step for replenishing as candidates for inter prediction information;
Motion compensated prediction in which one inter prediction information candidate is selected from the inter prediction information candidates after supplementation in the candidate supplementation step, and the prediction block to be decoded is inter-predicted by the selected inter prediction information candidate And a step of causing a computer to execute the steps. A moving picture decoding program for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving step for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate in which the inter-picture distance between the picture including the prediction block to be decoded and the reference picture of the first prediction is 1, and the motion vector of the first prediction is scaled to an integral multiple Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or the picture including the prediction block to be decoded and the reference picture of the second prediction In a candidate for bi-prediction inter prediction information having a inter-picture distance of 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction to an integral multiple is used as the first prediction motion vector, thereby generating a new bi-prediction motion vector. A candidate replenishment step of generating candidates for inter prediction information and replenishing them as candidates for bi prediction inter prediction information;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate supplementation step, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. A moving picture decoding program which causes a computer to execute a motion compensation prediction step for performing inter prediction of bi-prediction of a block. A moving picture decoding program for decoding a coded bit string obtained by coding the moving picture using motion compensated prediction in units of blocks obtained by dividing each picture of the moving picture,
From a prediction block adjacent to a prediction block to be decoded in a B slice, or a prediction block existing at the same position or in the vicinity of the prediction block to be decoded in a decoded picture temporally different from the prediction block to be decoded. A prediction information deriving step for deriving candidates for bi-prediction inter prediction information including vector information and reference picture information;
A bi-prediction inter prediction information candidate having an inter-picture distance between the picture including the prediction block to be decoded and the first prediction reference picture other than 1, and the motion vector of the first prediction is scaled by −1 Is used as another second prediction motion vector to generate a new bi-prediction inter prediction information candidate, or a picture including a prediction block to be decoded and a picture of a second prediction reference picture In a candidate for bi-prediction inter prediction information having an inter-distance other than 1, a motion vector of the second prediction obtained by scaling the motion vector of the second prediction by −1 times is used as a first prediction motion vector, whereby a new bi-prediction inter prediction information is obtained. A candidate replenishment step of generating prediction information candidates and replenishing them as bi-prediction inter prediction information candidates;
One candidate of inter prediction information for bi-prediction is selected from the candidates for inter-prediction information for bi-prediction after supplementation in the candidate supplementation step, and prediction of the decoding target is performed based on the candidate for inter-prediction information for bi-prediction selected. A moving picture decoding program which causes a computer to execute a motion compensation prediction step for performing inter prediction of bi-prediction of a block.

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