JP2015228680A - Moving image decoder, moving image decoding method, moving image decoding program, receiver, reception method and reception program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that compression of encoding information and reduction of a whole code amount are required in a conventional image encoding system using motion compensation prediction.SOLUTION: A prediction motion vector candidate generation section 221 predicts prediction motion vector candidates from any motion vectors of decoded blocks adjacent to a decoding object block in the same picture as the decoding object block, generates the candidates of a plurality of prediction motion vectors and registers them in a prediction motion vector candidate list. A limiting section for the number of prediction motion vector candidates 224 limits the number of candidates of the prediction motion vectors, which are registered in the prediction motion vector candidate list, to the maximum number of candidates, which corresponds to a size of the prediction block. A prediction motion vector selecting section 225 selects the prediction motion vector from the prediction motion vector candidate list on the basis of information showing an index of the prediction motion vector to be selected in a decoded prediction motion vector candidate list.

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. A technique for predicting motion by this motion compensation is called inter 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. In the B picture, a maximum of two pictures can be selected from the encoded / decoded reference pictures and used for inter prediction. The predictions from these two reference pictures are distinguished as L0 prediction (list 0 prediction) mainly used as forward prediction and L1 prediction (list 1 prediction) mainly used as backward prediction.

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

In a moving picture coding system that performs motion compensation, a prediction process is performed on a motion vector in order to reduce the amount of code of the motion vector generated in each block. MPEG-4 AVC / H
. In H.264, using the fact that the motion vector to be encoded has a strong correlation with the motion vectors of neighboring neighboring blocks, a prediction motion vector is calculated by performing prediction from neighboring neighboring blocks, and the coding target motion vector is calculated. A difference motion vector that is a difference between the motion vector and the predicted motion vector is calculated, and the difference motion vector is encoded to reduce the amount of codes.

Specifically, as shown in FIG. 36 (a), a median value is calculated from the motion vectors of neighboring blocks A, B, and C in the vicinity to obtain a predicted motion vector, and the difference between the motion vector and the predicted motion vector By taking this, the amount of code of the motion vector is reduced. However, if the size and shape of the encoding target block and the adjacent block are different as shown in FIG. 36B, when there are a plurality of adjacent blocks on the left, When there is an adjacent block, the leftmost block is used as a prediction block, and prediction is performed from the determined motion vector of the prediction block.

JP 2011-147172 A

However, in the conventional method, since only one prediction vector is obtained, the prediction accuracy of the prediction motion vector may be lowered depending on the image, and the encoding efficiency may not be improved.

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

The present invention has been made in view of such a situation, and an object of the present invention is to provide a moving picture decoding technique for improving the coding efficiency by calculating the prediction motion vector candidates and thereby reducing the code amount of the difference motion vector. Is to provide. Another object is to provide a moving picture decoding technique that improves encoding efficiency by calculating encoding information candidates to reduce the amount of encoded information.

  A moving picture decoding apparatus that decodes a coded bit sequence in which a moving picture is coded using a motion vector in units of blocks obtained by dividing each picture, and indicates an index of a predicted motion vector to be selected in a predicted motion vector candidate list Deriving first and second predicted motion vector candidates from a decoding unit that decodes information, and a motion vector of a decoded block adjacent to the decoding target block in the same picture as the decoding target block, and decoding A motion vector predictor candidate generation unit that derives a third motion vector predictor candidate from a motion vector of a block in a decoded picture different from the target block, and the first, second, and second conditions that satisfy a predetermined condition A motion vector predictor candidate registration unit for registering 3 motion vector predictor candidates in a motion vector predictor candidate list; When the value of the first motion vector predictor candidate registered in the motion vector predictor candidate list by the motion vector predictor candidate registration unit is the same as the value of the second motion vector predictor candidate, the motion vector predictor candidate list When the number of motion vector predictor redundancy determination units that delete the second motion vector predictor candidate and the number of motion vector predictor candidates registered in the motion vector predictor candidate list is smaller than a predetermined number (a natural number of 2 or more), Repeat until the number of motion vector predictor candidates reaches a predetermined number, and register motion vector predictor candidates having a value of (0, 0) in the motion vector predictor candidate list at a position corresponding to the number of motion vector predictor candidates. Based on the information indicating the decoded prediction motion vector candidate restriction unit and the index of the decoded prediction motion vector to be selected. A prediction motion vector selection unit that selects a prediction motion vector of the decoding target block from the prediction motion vector candidate list, and the prediction motion vector candidate redundancy determination unit includes a value of a first prediction motion vector candidate and the prediction motion vector candidate There is provided a moving picture decoding apparatus characterized by not comparing a value of a second motion vector predictor candidate with a value of a third motion vector predictor candidate.

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

According to the present invention, a plurality of predicted motion vectors are calculated, an optimal predicted motion vector is selected from the plurality of predicted motion vectors, the generated code amount of the difference motion vector is reduced,
Encoding efficiency can be improved.

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 a prediction block group. It is a figure explaining a prediction block group. It is a figure explaining a prediction block group. It is a figure explaining a prediction block group. It is a figure explaining a prediction block group. It is a figure explaining the syntax of the bit stream in the slice level regarding the prediction method of a motion vector. It is a figure explaining the syntax of the bit stream in the prediction block level regarding the prediction method of a motion vector. It is a figure explaining an example of the entropy code of the syntax element of a prediction motion vector index. It is a block diagram which shows the detailed structure of the difference motion vector calculation part of FIG. FIG. 3 is a block diagram illustrating a detailed configuration of a motion vector calculation unit in FIG. 2. It is a flowchart which shows the difference motion vector calculation process procedure of the difference motion vector calculation part of FIG. It is a flowchart which shows the motion vector calculation process procedure of the motion vector calculation part of FIG. It is a flowchart which shows the final candidate number setting process sequence of a motion vector predictor. It is a flowchart which shows the process of derivation | leading-out of the motion vector predictor candidate, and a motion vector predictor list construction process. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the scaling calculation process procedure of a motion vector. It is a flowchart which shows the scaling calculation process procedure of the motion vector by integer calculation. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the derivation | leading-out process of the picture of a different time. It is a flowchart which shows the prediction block candidate derivation | leading-out process of the picture of a different time. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the candidate derivation | leading-out process procedure of a motion vector predictor. It is a flowchart which shows the scaling calculation process procedure of a motion vector. It is a flowchart which shows the scaling calculation process procedure of the motion vector by integer calculation. It is a flowchart which shows the registration process procedure of the candidate of a motion vector predictor to a motion vector predictor candidate list. It is a flowchart which shows the deletion process procedure of the redundant motion vector predictor candidate from a motion vector predictor candidate list. It is a flowchart which shows the restriction | limiting process procedure of the number of prediction motion vector candidates. It is a flowchart which shows the registration process procedure of the candidate of a motion vector predictor to a motion vector predictor candidate list. It is a flowchart which shows the registration process procedure of the candidate of a motion vector predictor to a motion vector predictor candidate list. It is a figure explaining the calculation method of the conventional prediction motion vector.

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. In addition, by calculating a plurality of predicted motion vectors from the motion vectors of the surrounding blocks that have been encoded, and calculating and encoding a difference vector between the motion vector of the block to be encoded and the selected predicted motion vector Reduce the amount of code. Or
By using the encoding information of the surrounding blocks that have already been encoded, the amount of code is reduced by estimating the encoding information of the block to be encoded. Also, in the case of decoding a moving image, a plurality of predicted motion vectors are calculated from the motion vectors of the peripheral blocks that have been decoded, and a decoding target is calculated from the difference vector decoded from the encoded stream and the selected predicted motion vector. The motion vector of the block is calculated and decoded. Alternatively, the encoding information of the decoding target block is estimated by using the encoding information of the peripheral blocks that have been decoded.

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

(About tree blocks and coding blocks)
In the embodiment, as shown in FIG. 3, the picture is equally divided into square units of any same size. This unit is defined as a tree block, and is a block to be encoded or decoded in a picture (a block to be encoded in the encoding process and a block to be decoded in the decoding process. Hereinafter, unless otherwise noted, 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 divided into 4 tree blocks.
It is an encoded block that is obtained by further dividing the block obtained by dividing into four hierarchically twice.
It is a coding block of the minimum size.

(About prediction mode)
Intra prediction (MODE) that performs prediction from surrounding image signals that have already been decoded in units of coding blocks
_INTRA) and inter prediction (MODE_INTER) that performs prediction from the image signal of a decoded picture
). 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)
Intra-prediction (MODE_INTRA) and inter-prediction (MODE)
When performing (_INTER), in order to reduce the unit for switching between the intra prediction method and the inter prediction method, prediction is performed by dividing the coded block as necessary. 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 luminance signal of the coding block is regarded as one prediction block without being divided (FIG. 4 (a))
The partition mode (PartMode) is divided into 2N × 2N partitions (PART_2Nx2N), the luminance signal of the coding block is horizontally divided into two prediction blocks (FIG. 4 (b)) (Panel mode (Pa)
rtMode) is divided into 2N × N (PART_2NxN), the luminance signal of the encoded block is divided in the vertical direction, and the encoded block is divided into two prediction blocks (FIG. 4C) (PartMo
de) is N × 2N division (PART_Nx2N), and the division mode (PartMode) of the luminance signal of the encoded block is made into four prediction blocks by horizontal and vertical equal division (FIG. 4D) is N × N.
Each is defined as a division (PART_NxN). 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. FIG.
In the 2N × N division (PART_2NxN) shown in FIG. 2, 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. N shown in FIG.
In the × 2N division (PART_Nx2N), 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. N × N division (P
ART_NxN) sets the partition index PartIdx of the upper left prediction block to 0, the partition index PartIdx of the upper right prediction block to 1, and the partition index Par of the lower left prediction block
tIdx is set to 2, and the division index PartIdx of the lower right prediction block is set to 3.

When the prediction mode (PredMode) is inter prediction (MODE_INTER), the partition mode (PartMode) is 2N × 2N partition (PART_2Nx2N) except for the coding block D which is the smallest coding block.
) 2N × N partition (PART_2NxN) and N × 2N partition (PART_Nx2N) are defined, and only the coding block D, which is the smallest coding block, has a partition mode (PartMode) of 2N × 2N partition (PA).
RT_2Nx2N), 2N x N split (PART_2NxN), and N x 2N split (PART_Nx2N) plus N x
N division (PART_NxN) is defined. In addition to the smallest encoded block, N × N division (PART_N
The reason for not defining xN) is that, except for the smallest encoded block, the encoded block can be divided into four to represent a small encoded 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 conversion block of the present embodiment is the origin (
0,0), and 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. 2:
Even in the case of 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.

(About prediction block groups)
A group composed of a plurality of prediction blocks is defined as a prediction block group. FIG.
6, 7 and 8 are diagrams for explaining a prediction block group adjacent to a prediction block to be encoded or decoded in the same picture as the prediction block to be encoded or decoded.
FIG. 9 shows a prediction block that has already been encoded or decoded and is present in a decoded picture that is temporally different from the prediction block to be encoded or decoded and is present at the same position as or near the prediction block to be encoded or decoded. It is a figure explaining a group. The prediction block group will be described with reference to FIGS. 5, 6, 7, 8, and 9.

As shown in FIG. 5, the prediction block A1 adjacent to the left side of the prediction block to be encoded or decoded in the same picture as the prediction block to be encoded or decoded, and the prediction block to be encoded or decoded A first prediction block group including a prediction block A0 adjacent to the lower left vertex is defined as a prediction block group adjacent to the left side.

In addition, as shown in FIG. 6, even when the size of the prediction block adjacent to the left side of the prediction block to be encoded or decoded is larger than the prediction block to be encoded or decoded, the prediction adjacent to the left side according to the above condition. If the block A is adjacent to the left side of the prediction block to be encoded or decoded, the prediction block A1 is set. If the block A is adjacent to the lower left vertex of the prediction block to be encoded or decoded, the prediction block A0 is set. . In the example of FIG. 6, the prediction block A0
And the prediction block A1 is the same prediction block.

In addition, as shown in FIG. 7, when the size of the prediction block adjacent to the left side of the prediction block to be encoded or decoded is smaller than the prediction block to be encoded or 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 A1 adjacent to the left side.

A prediction block B1 adjacent to the upper side of the prediction block to be encoded or decoded in the same picture as the prediction block to be encoded or decoded, and a prediction block adjacent to the upper right vertex of the prediction block to be encoded or decoded A second prediction block group including B0 and a prediction block B2 adjacent to the upper left vertex of the prediction block to be encoded or decoded is defined as a prediction block group adjacent to the upper side.

In addition, as shown in FIG. 8, even when the size of the prediction block adjacent to the upper side of the prediction block to be encoded or decoded is larger than the prediction block to be encoded or decoded, the prediction adjacent to the upper side is also performed according to the above condition. If the block B is adjacent to the upper side of the prediction block to be encoded or decoded, the prediction block B1; if the block B is adjacent to the upper right vertex of the prediction block to be encoded or decoded, the prediction block B0; If it is adjacent to the top left vertex of the prediction block to be encoded or decoded, the prediction block is B2. In the example of FIG. 8, the prediction block B0, the prediction block B1, and the prediction block B2 are the same prediction block.

As shown in FIG. 7, when the size of the prediction block adjacent to the upper side of the prediction block to be encoded or decoded is smaller than that of the prediction block to be encoded or decoded and there are a plurality of prediction blocks, the embodiment In FIG. 5, only the rightmost prediction block B10 among the prediction blocks adjacent on the upper side is set as the prediction block B1 adjacent on the upper side.

As shown in FIG. 9, in a picture that has been encoded or decoded that is temporally different from a prediction block to be encoded or decoded, an existing code that exists at the same position as or near the prediction block to be encoded or decoded A third prediction block group composed of the predicted or decoded prediction block groups T0 and T1 is defined as a prediction block group at different times.

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

(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 order. Depending on the value of POC, it can be determined whether they are the same picture,
It is possible to determine the front-to-back relationship between pictures in the output order and 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 a picture with a smaller POC value is a picture that is output earlier in time.
The difference in OC indicates the distance between pictures in the time axis direction.

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

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 stores the stored image signal of the picture to be encoded.
The data is supplied to the motion vector detection unit 102, the prediction method determination unit 106, and the residual signal generation unit 107 in predetermined pixel block units. 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 of 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 115 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 106.

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 114, and will be described later. The motion vector detection unit 102 selects an optimal motion vector predictor from a plurality of motion vector predictor candidates registered in the motion vector list and registered in the motion vector predictor list. And the calculated difference motion vector is supplied to the prediction method determination unit 106. 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 106. The detailed configuration and operation of the difference motion vector calculation unit 103 will be described later.

The inter prediction information estimation unit 104 estimates inter prediction information in merge mode. The merge mode refers to inter prediction information such as a prediction mode of the prediction block, a reference index (information for specifying a reference picture used for motion compensation prediction from a plurality of reference pictures registered in the reference list), a motion vector, and the like. Is a mode in which inter prediction information of an adjacent inter-predicted prediction block that has been encoded or an inter-predicted prediction block of a different picture is used. A plurality of merge candidates (inter prediction information candidates) are calculated using the encoded information of the already encoded prediction block stored in the encoded information storage memory 114, registered in the merge candidate list, and merged. An optimal merge candidate is selected from a plurality of merge candidates registered in the candidate list, and inter prediction information such as a prediction mode, a reference index, and a motion vector of the selected merge candidate is supplied to the motion compensation prediction unit 105. The merge index that identifies the selected merge candidate is supplied to the prediction method determination unit 106.

The motion compensation prediction unit 105 includes a motion vector detection unit 102 and an inter prediction information estimation unit 1.
A prediction image signal is generated by motion compensation prediction from the reference picture using the motion vector detected in 04, and the prediction image signal is supplied to the prediction method determination unit 106. 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 prediction method determination unit 106 evaluates the code amount of the difference motion vector, the distortion amount between the prediction image signal and the image signal, and the like, so that inter prediction (in an optimal coding block unit) is selected from a plurality of prediction methods. PredMo prediction mode that distinguishes between PRED_INTER) and intra prediction (PRED_INTRA)
de, the partition mode PartMode is determined, and in inter prediction (PRED_INTER), the prediction method such as whether or not the merge mode is determined in units of prediction blocks, merge index in merge mode,
When not in merge mode, the inter prediction flag, the motion vector predictor index, L0,
The reference index of L1, a difference motion vector, and the like are determined, and encoded information corresponding to the determination is supplied to the first encoded bit string generation unit 109.

Further, the prediction method determination unit 106 stores information indicating the determined prediction method and encoded information including a motion vector according to the determined prediction method in the encoded information storage memory 114. The encoded information stored here is a motion of the reference indexes refIdxL0, refIdxL1, L0, and L1 of the flags predFlagL0, predFlagL1, L0, and L1 indicating whether to use the prediction mode PredMode, the partition mode PartMode, the L0 prediction, and the L1 prediction. Vectors mvL0, mvL1, etc.
Here, when the prediction mode PredMode is intra prediction (PRED_INTRA), a flag predFlagL0 indicating whether to use L0 prediction or a flag predFlagL1 indicating whether to use L1 prediction
Are both 0. On the other hand, when the prediction mode PredMode is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), a flag pre indicating whether to use L0 prediction
dFlagL0 is 1, and flag predFlagL1 indicating whether to use L1 prediction is 0. When the inter prediction mode is L1 prediction (Pred_L1), a flag p indicating whether or not to use L0 prediction
RedFlagL0 is 0, and flag predFlagL1 indicating whether to use L1 prediction is 1. Flag p indicating whether to use L0 prediction when the inter prediction mode is bi-prediction (Pred_BI)
The flags predFlagL1 indicating whether to use redFlagL0 and L1 prediction are both 1. The prediction method determination unit 106 outputs a prediction image signal corresponding to the determined prediction mode to the residual signal generation unit 10.
7 and the decoded image signal superimposing unit 113.

The residual signal generation unit 107 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 108.

The orthogonal transform / quantization unit 108 performs orthogonal transform and quantization on the residual signal in accordance with the quantization parameter to generate an orthogonal transform / quantized residual signal, and a second encoded bit string generation unit 110 and the inverse quantization / inverse orthogonal transform unit 112. Further, the orthogonal transform / quantization unit 108
Stores the quantization parameter in the encoded information storage memory 114.

The first encoded bit string generation unit 109 adds information corresponding to the prediction method determined by the prediction method determination unit 106 for each encoding block and prediction block, in addition to the information in units of sequences, pictures, slices, and encoding blocks. Encoding information is encoded. Specifically, when the prediction mode PredMode for each coding block is inter prediction (PRED_INTER), a flag for determining whether or not the mode is a merge mode, a merge index when the mode is merge mode, an inter prediction mode when the mode is not merge mode, and a reference index In addition, encoding information such as information on a prediction motion vector index and a difference motion vector is encoded according to a prescribed syntax rule described later to generate a first encoded bit string, which is supplied to the multiplexing unit 111. If the number of motion vector predictor candidates registered in the motion vector predictor list is 1, the motion vector predictor index mvp_idx can be specified as 0, and is not encoded. In the present embodiment, the number of motion vector predictor candidates is set according to the size of the prediction block to be encoded, as will be described later. Therefore, the first encoded bit string generation unit 109 sets the number of motion vector predictor candidates according to the size of the prediction block to be encoded. When the set number of candidates is larger than 1, the motion vector predictor index Is encoded.

The second encoded bit sequence generation unit 110 generates a second encoded bit sequence by entropy encoding the residual signal that has been orthogonally transformed and quantized according to a prescribed syntax rule, and supplies the second encoded bit sequence to the multiplexing unit 111. The multiplexing unit 111 multiplexes the first encoded bit string and the second encoded bit string in accordance with a prescribed syntax rule, and outputs a bit stream.

The inverse quantization / inverse orthogonal transform unit 112 calculates a residual signal by performing inverse quantization and inverse orthogonal transform on the orthogonal transform / quantized residual signal supplied from the orthogonal transform / quantization unit 108 to perform decoding. This is supplied to the image signal superimposing unit 113. The decoded image signal superimposing unit 113 superimposes the predicted image signal according to the determination by the prediction method determining unit 106 and the residual signal that has been inverse quantized and inverse orthogonal transformed by the inverse quantization / inverse orthogonal transform unit 112 to decode the decoded image. Is generated and stored in the decoded image memory 115. In addition, a filtering process for reducing distortion such as block distortion due to encoding is performed on the decoded image,
It may be stored in the decoded image memory 115.

FIG. 2 is a block diagram showing the configuration of the moving picture decoding apparatus according to the embodiment of the present invention corresponding to the moving picture encoding apparatus of FIG. The moving picture decoding apparatus according to the embodiment includes a separation unit 201, a first encoded bit string decoding unit 202, a second encoded bit string decoding unit 203, a motion vector calculation unit 204,
Inter prediction information estimation unit 205, motion compensation prediction unit 206, inverse quantization / inverse orthogonal transform unit 207
, Decoded image signal superimposing unit 208, encoded information storage memory 209, and decoded image memory 21
0 is 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 configurations of the inverse orthogonal transform unit 207, the decoded image signal superimposing unit 208, the encoded information storage memory 209, and the decoded image memory 210 are the motion compensated prediction unit 105 of the moving image encoding device in FIG.
Each of the configurations of the inverse orthogonal transform unit 112, the decoded image signal superimposing unit 113, the encoded information storage memory 114, and the decoded image memory 115 has a corresponding function.

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

The first encoded bit string decoding unit 202 decodes the supplied encoded bit string to obtain sequence, picture, slice, encoded block unit information, and predicted block unit encoded information. Specifically, in the prediction mode PredMode for determining whether the prediction is inter prediction (PRED_INTER) or intra prediction (PRED_INTRA) for each coding block, split mode PartMode, and inter prediction (PRED_INTER), a flag for determining whether the mode is merge mode, When the merge mode is selected, the merge index is decoded. When the merge mode is not selected, the encoded information related to the inter prediction mode, the predicted motion vector index, the difference motion vector, and the like is decoded according to a predetermined syntax rule to be described later, and the encoded information is a motion vector calculation unit. 204 or the inter prediction information estimation unit 205. Note that, when the mode is not the merge mode, when there is one motion vector predictor candidate registered in the motion vector predictor list to be described later, the motion vector predictor index can be identified as 0, so the motion vector predictor index is not encoded. The predicted motion vector index is set to 0. In the present embodiment, the number of motion vector predictor candidates is set according to the size of the prediction block to be decoded, as will be described later. Therefore, the first encoded bit string decoding unit 202 sets the number of motion vector predictor candidates according to the size of the prediction block to be decoded, and decodes the motion vector predictor index when the set candidate number is greater than 1. To do.

The second encoded bit string decoding unit 203 decodes the supplied encoded bit string to perform orthogonal transform /
The quantized residual signal is calculated, and the orthogonal transform / quantized residual signal is supplied to the inverse quantization / inverse orthogonal transform unit 207.

When the prediction block to be decoded is not in the merge mode, the motion vector calculation unit 204 uses the encoded information of the already decoded image signal stored in the encoded information storage memory 209 to generate a plurality of prediction motion vector candidates. And the motion vector is registered in a motion vector predictor list, which will be described later, and a motion vector predictor that is decoded and supplied from the plurality of motion vector predictor candidates registered in the motion vector predictor list by the first encoded bit string decoding unit 202. A prediction motion vector corresponding to the index is selected, a motion vector is calculated from the difference vector decoded by the first encoded bit string decoding unit 202 and the selected prediction motion vector, and the motion compensated prediction unit 206 together with other encoded information. And is stored in the encoded information storage memory 209. The encoding information of the prediction block to be supplied / stored here includes the prediction mode PredMode and the division mode PartMode.
, L0 prediction, and flags predFlagL0, predFlagL1, L indicating whether to use L1 prediction
0, L1 reference indices refIdxL0, refIdxL1, L0, L1 motion vectors mvL0, mvL1
Etc. Here, when the prediction mode is intra prediction (PRED_INTRA), a flag predFlagL0 indicating whether to use the L0 prediction, a flag predFlag indicating whether to use the L1 prediction
Both L1 are 0. On the other hand, when the prediction mode PredMode is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), a flag p indicating whether or not to use L0 prediction
redFlagL0 is 1, and flag predFlagL1 indicating whether to use L1 prediction is 0. When the inter prediction mode is L1 prediction (Pred_L1), the flag predFlagL0 indicating whether to use L0 prediction is 0, and the flag predFlagL1 indicating whether to use L1 prediction is 1. When the inter prediction mode is bi-prediction (Pred_BI), a flag predFlagL0 indicating whether to use L0 prediction and a flag predFlagL1 indicating whether to use L1 prediction are both 1. The detailed configuration and operation of the motion vector calculation unit 204 will be described later.

The inter prediction information estimation unit 205 estimates the inter prediction information in the merge mode when the prediction block to be decoded is in the merge mode. Using the encoded information of the already decoded prediction block stored in the encoded information storage memory 114, a plurality of merge candidates are calculated and registered in the merge candidate list, and the plurality of merge candidates registered in the merge candidate list First among merge candidates
The merge candidate corresponding to the merge index decoded and supplied by the encoded bit string decoding unit 202 is selected, and the prediction mode PredMode, the division mode PartMode, and L0 of the selected merge candidate are selected.
PredFlagL0, predFlagL1, L0, L indicating whether to use prediction and L1 prediction
The inter prediction information such as the motion vectors mvL0 and mvL1 of the reference indices refIdxL0, refIdxL1, L0, and L1 of 1 is supplied to the motion compensation prediction unit 206 and the encoded information storage memory 20
9 is stored.

The motion compensation prediction unit 206 generates a prediction image signal by motion compensation prediction from the reference picture using the motion vector calculated by the motion vector calculation unit 204, and supplies the prediction image signal to the decoded image signal superimposition unit 208. 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 inverse quantization / inverse orthogonal transform unit 207 performs inverse orthogonal transform and inverse quantization on the orthogonal transform / quantized residual signal decoded by the first encoded bit string decoding unit 202, and performs inverse orthogonal transform / An inverse quantized residual signal is obtained.

The decoded image signal superimposing unit 208 superimposes the predicted image signal subjected to motion compensation prediction by the motion compensation prediction unit 206 and the residual signal subjected to inverse orthogonal transform / inverse quantization by the inverse quantization / inverse orthogonal transform unit 207. As a result, the decoded image signal is decoded and stored in the decoded image memory 210. When stored in the decoded image memory 210, the decoded image may be stored in the decoded image memory 210 after filtering processing for reducing block distortion or the like due to encoding is performed on the decoded image.

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

FIG. 10 shows a first syntax structure described in the slice header in units of slices of the bitstream generated according to the present embodiment. However, only syntax elements relevant to the present embodiment are shown. When the slice type is B, a picture colPic at a different time used when calculating a motion vector prediction candidate or merge candidate in the temporal direction is a reference list of L0 or a reference of L1 of a picture including a prediction block to be processed. Flag collocated_from_l0_f indicating which reference picture registered in the list is to be used
A lag is installed. Details of the flag collocated_from_l0_flag will be described later.

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

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

Next, when merge_flag [x0] [y0] is 1, it indicates merge mode, and the merge list index syntax element merge_idx [x0] [y0, which is a list of merge candidates to be referred to
] Is installed. 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.

On the other hand, when merge_flag [x0] [y0] is 0, it indicates that it is not the merge mode. When the slice type is B, the syntax element that identifies the inter prediction mode inter_pred_flag [x0] [y0
], And L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI) are identified by this syntax element. 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 the prediction block located at L0 and the differential motion vector, and ref_idx_l1
[x0] [y0] and mvd_l1 [x0] [y0] [j] are the L1 reference index and the differential motion vector of the prediction block located at (x0, y0) in the picture, respectively. Further, j represents a differential motion vector component, j represents 0 as an x component, and j represents 1 as a y component. Next, when the number of differential motion vector candidates set in accordance with the size of the prediction block to be encoded or decoded is larger than 1, the index of the prediction motion vector list that is a list of prediction motion vector candidates to be referred to Syntax elements mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] are installed. 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 It is the prediction motion vector index of L0 and L1 of the prediction block located. The function NumMVPCand (LX) represents a function for calculating the total number of prediction motion vector candidates of the prediction block in the prediction direction LX (X is 0 or 1), and depends on the size of the prediction block to be encoded or decoded, which will be described later. The same value as the defined final candidate number finalNumMVPCand is set. FIG. 12 shows a syntax element mvp_idx_l0 [x0] [y0] of a predicted motion vector index for each specified number of predicted motion vector candidates.
It is an example of an entropy code of mvp_idx_l1 [x0] [y0]. Predicted motion vector index mv
p_idx_lx [x0] [y0] is the number of motion vector predictor candidates according to the motion vector prediction method.
Encoded when (LX) is greater than one. This is because if the total number of motion vector predictor candidates is 1, one of the motion vector predictors is a motion vector predictor, so that the motion vector predictor candidate to be referred to is determined without transmitting mvp_idx_lx [x0] [y0]. Number of motion vector candidates NumMVPCand (LX)
Is 2, when the motion vector predictor index is 0, the syntax elements mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] of the motion vector predictor index are “0” and the motion vector predictor index is When 1, the predicted motion vector index syntax element mv
The codes of p_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] are “1”. Number of prediction motion vector candidates
When NumMVPCand (LX) is 3, when the motion vector predictor index is 0, the sign of the motion vector index syntax elements mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] is '0'
When the motion vector predictor index is 1, when the motion vector index syntax elements mvp_idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] are '10' and the motion vector predictor index is 2, , Predictive motion vector index syntax element mvp_
The codes of idx_l0 [x0] [y0] and mvp_idx_l1 [x0] [y0] are “11”. In the embodiment of the present invention, the number of motion vector predictor candidates is set according to the size of the prediction block to be encoded or decoded, and details will be described later.

The motion vector prediction method according to the embodiment is implemented in the difference motion vector calculation unit 103 of the video encoding device in FIG. 1 and the motion vector calculation unit 204 of the video decoding device in FIG.

A motion vector prediction method according to an embodiment will be described with reference to the drawings. The motion vector prediction method is performed in any of the encoding and decoding processes for each prediction block constituting the encoding block. When the prediction mode of the prediction block is inter prediction (MODE_INTER) and not the merge mode, in the case of encoding, the encoded motion vector used when calculating the differential motion vector to be encoded from the motion vector to be encoded is used. In the case of deriving the predicted motion vector, the decoding is performed when the predicted motion vector is derived using the decoded motion vector used when calculating the motion vector to be decoded.

(Prediction of motion vector in encoding)
The operation of the motion vector prediction method according to the embodiment in the video encoding device that encodes a video bitstream based on the above-described syntax will be described. The motion vector prediction method is a method in which motion compensated prediction is performed in units of slices, that is, when the slice type is a P slice (unidirectional prediction slice) or a B slice (bidirectional prediction slice). The prediction mode is an inter prediction (MODE_INTER) and is applied to a prediction block that encodes or decodes a differential motion vector that is not a merge mode.

FIG. 13 is a diagram showing a detailed configuration of the differential motion vector calculation unit 103 of the moving picture encoding device of FIG. A portion surrounded by a thick frame line in FIG. 13 indicates the differential motion vector calculation unit 103.

Further, the part surrounded by a thick dotted line inside thereof shows an operation unit of a motion vector prediction method described later, and is similarly installed in a video decoding device corresponding to the video encoding device of the embodiment, The same derivation result consistent with encoding and decoding is obtained. Hereinafter, a motion vector prediction method in encoding will be described with reference to FIG.

In the present embodiment, the final number of predicted motion vectors finalNumMVPCand is set according to the size of the prediction block to be encoded or decoded. Difference motion vector calculation unit 10
3 is the size sizePUNumMVPCa defined by the size of the prediction block of the luminance signal to be encoded.
If less than nd, set finalNumMVPCand to a number less than the latter, otherwise final
Set NumMVPCand to a number greater than the former. In this embodiment, the specified size
If sizePUNumMVPCand is set to 8x8 and the size of the prediction block of the luminance signal to be encoded or decoded is equal to or smaller than the specified sizePUNumMVPCand, finalNumMVPCand is set to 1; otherwise, finalNumMVPCand is set to 2.

When the size of the prediction block is small, the number of prediction blocks per unit area increases. Therefore, the number of processes for deleting the redundant motion vector predictor candidates described later and the process for encoding the motion vector predictor index described above are reduced. It will increase.

Therefore, in the present embodiment, when the prediction block to be encoded and decoded is equal to or smaller than the specified size, the final candidate number finalNumMVPCand is set to 1, and the process of deleting redundant prediction motion vector candidates and the prediction motion vector index are By skipping the encoding and decoding processes, the amount of processing is reduced. Further, when the final candidate number finalNumMVPCand is 1, it is not necessary to encode the motion vector predictor index, so that it is possible to reduce the amount of entropy encoding processing.

The difference motion vector calculation unit 103 includes a prediction motion vector candidate generation unit 121, a prediction motion vector candidate registration unit 122, a prediction motion vector redundant candidate deletion unit 123, a prediction motion vector candidate number limit unit 124, and a prediction motion vector candidate code amount calculation unit. 125, predicted motion vector selection unit 1
26, and a motion vector subtraction unit 127.

The difference motion vector calculation process in the difference motion vector calculation unit 103 is performed by using the difference motion vector of the motion vector used in the inter prediction method selected in the encoding target block as L0, L
Each one is calculated. Specifically, the prediction mode PredMode of the encoding target block is inter prediction (MODE_INTER), and the inter prediction mode of the encoding target block is L0 prediction (Pred_L
0), a predicted motion vector list mvpListL0 of L0 is calculated, and the predicted motion vector mvpL
0 is selected, and a differential motion vector mvdL0 of the motion vector of L0 is calculated. When the inter prediction mode (Pred_L1) of the encoding target block is L1 prediction, the motion vector list m of L1
vpListL1 is calculated, a predicted motion vector mvpL1 is selected, and a differential motion vector mvdL1 of the L1 motion vector is calculated. The inter prediction mode of the current block is bi-prediction (Pred_BI
), Both L0 prediction and L1 prediction are performed, and the L0 prediction motion vector list mvpListL0
, L0 predicted motion vector mvpL0 is selected, L0 motion vector mvL0 differential motion vector mvdL0 is calculated, L1 predicted motion vector list mvpListL1 is calculated, and L1 predicted motion vector mvpL1 is calculated Then, the differential motion vector mvdL1 of the L1 motion vector mvL1 is calculated.

Difference motion vector calculation processing is performed for each of L0 and L1, but both L0 and L1 are common processing. Therefore, in the following description, L0 and L1 are represented as a common LX. In the process of calculating the differential motion vector of L0, X is 0, and in the process of calculating the differential motion vector of L1, X is 1. In addition, during the process of calculating the LX differential motion vector,
When referring to the information of the other list instead of LX, the other list is represented as LY.

For each of L0 and L1, the motion vector predictor candidate generation unit 121 has a prediction block group adjacent to the upper side (a prediction block group adjacent to the left side of the prediction block in the same picture as the prediction block to be encoded: A0 in FIG. 5). , A1), prediction block group adjacent to the left side (prediction block group adjacent to the upper side of the prediction block in the same picture as the prediction block to be encoded: B0, B1, B2 in FIG. 5), prediction blocks at different times Group (predicted block group that has already been encoded and exists at the same position as or near the predicted block in a temporally different picture from the predicted block to be encoded: T0 and T in FIG.
One motion vector mvLXA, mvLXB, mvLXCol is derived for each prediction block group from the three prediction block groups of 1), and is supplied to the prediction motion vector candidate registration unit 122 as a prediction motion vector candidate. Hereinafter, mvLXA and mvLXB are spatially predicted motion vectors,
mvLXCol is called a temporal motion vector predictor. When calculating the prediction motion vector candidates, encoding information such as the prediction mode of the encoded prediction block stored in the encoding information storage memory 114, the reference index for each reference list, the POC of the reference picture, the motion vector, etc. Is used.

These predicted motion vector candidates mvLXA, mvLXB, and mvLXCol are pictures to be encoded or decoded (pictures to be encoded in the encoding process, pictures to be decoded in the decoding process. Hereinafter, unless otherwise noted, It may be derived by scaling according to the relationship between the POC of the reference picture and the POC of the reference picture.

The motion vector predictor candidate generation unit 121 is in a predetermined order for each prediction block group.
For each prediction block in each prediction block group, the condition determination described later is performed, and the motion vector of the prediction block that first matches the condition is selected, and the predicted motion vector candidate mvLX
A, mvLXB, mvLXCol.

When calculating a prediction motion vector from a prediction block group adjacent to the left side, predictions adjacent to the upper side in the order from the bottom to the top of the prediction block group adjacent to the left side (order of A0 to A0 and A1 in FIG. 5). When calculating a prediction motion vector from a block group, prediction is performed from prediction block groups at different times in the order from right to left of the prediction block group adjacent to the upper side (order B0 to B0, B1, and B2 in FIG. 5). When calculating the motion vector, condition determination to be described later is performed for each prediction block in the order of T0 to T0 and T1 in FIG. 9, and the motion vector of the prediction block that first matches the condition is selected. Predicted motion vector candidates are mvLXA, mvLXB, and mvLXCol, respectively.

That is, in the left adjacent prediction block group, the lowest prediction block has the highest priority, and the priority is given from the bottom to the top. In the upper adjacent prediction block group, the rightmost prediction block Blocks have the highest priority and are prioritized from right to left. In the prediction block group at different times, the prediction block of T0 has the highest priority, and the priority is given in the order of T0 and T1.

(Explanation of loop for condition judgment of spatial prediction block)
For each adjacent prediction block of the left adjacent prediction block group and the upper adjacent prediction block group, in the scanning methods 1, 2, 3, and 4 described later, the following condition determinations 1 and 2
Each condition determination is applied in the priority order of 3, 4 and 4. However, with the exception of only scan method 5 described later, the respective condition determinations are applied in the priority order of condition determinations 1, 3, 2, and 4.
Condition determination 1: LX of difference motion vector calculation target of prediction block to be encoded or decoded
Prediction using the same reference index, that is, the same reference picture in the same reference list LX as that of the motion vector is also performed in the adjacent prediction block.
Condition determination 2: LX as a difference motion vector calculation target of a prediction block to be encoded or decoded
Although the reference list LY is different from the motion vector of, prediction using the same reference picture is performed in the adjacent prediction block.
Condition determination 3: LX as a difference motion vector calculation target of a prediction block to be encoded or decoded
In the same reference list LX as the motion vector of, prediction using different reference pictures is performed in the adjacent prediction block.
Condition determination 4: LX as a difference motion vector calculation target of a prediction block to be encoded or decoded
In the reference list LY different from the motion vector of, prediction using different reference pictures is performed in the adjacent prediction block.

If any of these conditions is met, it is determined that there is a motion vector that matches the condition in the prediction block, and the subsequent condition determination is not performed. Note that when the condition of Condition Determination 1 or Condition Determination 2 is met, the motion vector of the corresponding adjacent prediction block corresponds to the same reference picture, so that it is directly used as a prediction motion vector candidate.
Alternatively, if the condition of condition determination 4 is met, the motion vector of the corresponding adjacent prediction block corresponds to a different reference picture, so that it is calculated by scaling based on the motion vector to be a candidate for the motion vector predictor.

The following five methods can be set as a method of loop scanning of the spatial prediction block, depending on the above-described four conditions. The appropriateness of the prediction vector and the maximum processing amount differ depending on each method, and these are selected and set in consideration of them. The scanning method 1 will be described later in detail with reference to the flowcharts of FIGS. 19 to 23, but for other scanning methods 2 to 5, a person skilled in the art will know the procedure for performing the scanning methods 2 to 5 by using the scanning method 1. Since this is an item that can be appropriately designed in accordance with the procedure for carrying out the above, detailed description is omitted. In addition, although the loop process of the scan of the spatial prediction block in a moving image encoder is demonstrated here, the same process is also possible in a moving image decoder.

Scanning method 1:
Priority is given to the determination of a prediction motion vector that does not require scaling operation using the same reference picture, and two condition determinations are performed for each prediction block among the four condition determinations. Move on. Condition determination 1 and condition determination 2 are performed in the first round, and condition determination 3 and condition determination 4 are performed in the next round of prediction blocks.

Specifically, the condition determination is performed in the following priority order. (However, N is A or B)
1. Condition determination 1 of the prediction block N0 (same reference list LX, same reference picture)
2. Prediction block N0 condition determination 2 (different reference list LY, same reference picture)
3. Condition determination 1 of the prediction block N1 (same reference list LX, same reference picture)
4). Condition determination 2 of the prediction block N1 (different reference list LY, same reference picture)
5. 5. Condition determination 1 of the prediction block N2 (the same reference list LX, the same reference picture), only the prediction block group adjacent on the upper side 6. Condition determination 2 of the prediction block N2 (different reference list LY, the same reference picture), only the prediction block group adjacent on the upper side Condition determination 3 of the prediction block N0 (same reference list LX, different reference pictures)
8). Prediction block N0 condition decision 4 (different reference list LY, different reference picture)
9. Condition determination 3 of the prediction block N1 (same reference list LX, different reference pictures)
10. Prediction block N1 condition determination 4 (different reference list LY, different reference picture)
11. Condition determination 3 of the prediction block N2 (same reference list LX, different reference pictures),
Only the prediction block group adjacent on the upper side 12. Prediction block N2 condition determination 4 (different reference list LY, different reference picture)
, Only the upper adjacent prediction block group

According to the scanning method 1, since a prediction motion vector that does not require a scaling operation using the same reference picture is easily selected, there is an effect that the possibility that the code amount of the difference motion vector is reduced is increased. In addition, since the number of rounds of condition determination is a maximum of 2, the number of memory accesses to the encoded information of the prediction block is less than that in the scanning method 2 described later when considering implementation in hardware, and complexity is increased. Is reduced.

Scanning method 2:
Of the four condition determinations, one condition determination is performed for each prediction block. If the condition is not satisfied, the process proceeds to the condition determination for the adjacent prediction block. If the condition determination is performed four times for each prediction block, the process is terminated.

Specifically, the condition determination is performed in the following priority order. (However, N is A or B)
1. Condition determination 1 of the prediction block N0 (same reference list LX, same reference picture)
2. Condition determination 1 of the prediction block N1 (same reference list LX, same reference picture)
3. 3. Condition determination 1 of the prediction block N2 (same reference list LX, same reference picture), only the prediction block group adjacent on the upper side Prediction block N0 condition determination 2 (different reference list LY, same reference picture)
5. Condition determination 2 of the prediction block N1 (different reference list LY, same reference picture)
6). 6. Condition determination 2 of the prediction block N2 (different reference list LY, the same reference picture), only the prediction block group adjacent on the upper side Condition determination 3 of the prediction block N0 (same reference list LX, different reference pictures)
8). Condition determination 3 of the prediction block N1 (same reference list LX, different reference pictures)
9. 9. Condition determination 3 of the prediction block N2 (same reference list LX, different reference pictures), only the prediction block group adjacent on the upper side Prediction block N0 condition decision 4 (different reference list LY, different reference picture)
11. Prediction block N1 condition determination 4 (different reference list LY, different reference picture)
12 Prediction block N2 condition determination 4 (different reference list LY, different reference picture)
, Only the upper adjacent prediction block group

According to the scan method 2, since a predicted motion vector that does not require a scaling operation using the same reference picture is easily selected, there is an effect of increasing the possibility that the code amount of the difference motion vector is reduced. In addition, the number of rounds for condition determination is four times, and the number of memory accesses to the encoded information of the prediction block is larger than that in the scanning method 1 when considering implementation in hardware, but the prediction of the same reference list is performed. A motion vector is easily selected.

Scan method 3:
In the first round, if the condition determination of condition determination 1 is performed for each prediction block and the condition is not satisfied,
It moves to the condition judgment of the adjacent prediction block. In the next lap, condition determination is performed in order of condition determination 2, condition determination 3 and condition determination 4 for each prediction block, and then the process proceeds to the next.

Specifically, the condition determination is performed in the following priority order. (However, N is A or B)
1. Condition determination 1 of the prediction block N0 (same reference list LX, same reference picture)
2. Condition determination 1 of the prediction block N1 (same reference list LX, same reference picture)
3. 3. Condition determination 1 of the prediction block N2 (same reference list LX, same reference picture), only the prediction block group adjacent on the upper side Prediction block N0 condition determination 2 (different reference list LY, same reference picture)
5. Condition determination 3 of the prediction block N0 (same reference list LX, different reference pictures)
6). Prediction block N0 condition decision 4 (different reference list LY, different reference picture)
7). Condition determination 2 of the prediction block N1 (different reference list LY, same reference picture)
8). Condition determination 3 of the prediction block N1 (same reference list LX, different reference pictures)
9. Prediction block N1 condition determination 4 (different reference list LY, different reference picture)
10. Condition determination 2 of the prediction block N2 (different reference list LY, the same reference picture),
10. Only the prediction block group adjacent on the upper side Condition determination 3 of the prediction block N2 (same reference list LX, different reference pictures),
Only the prediction block group adjacent on the upper side 12. Prediction block N2 condition determination 4 (different reference list LY, different reference picture)
, Only the upper adjacent prediction block group

According to the scan method 3, a prediction motion vector that does not require a scaling operation using the same reference picture in the same reference list is easily selected, so that there is an effect that the possibility that the code amount of the difference motion vector is reduced is increased. In addition, since the maximum number of rounds for condition determination is two, the number of memory accesses to the encoded information of the prediction block is smaller than that in the scanning method 2 when considering implementation in hardware, and complexity is reduced. Is done.

Scanning method 4:
Priority is given to condition determination of the same prediction block, and four condition determinations are performed within one prediction block. If all the conditions are not met, it is determined that there is no motion vector matching the condition in the prediction block. The condition of the next prediction block is determined.

Specifically, the condition determination is performed in the following priority order. (However, N is A or B)
1. Condition determination 1 of the prediction block N0 (same reference list LX, same reference picture)
2. Prediction block N0 condition determination 2 (different reference list LY, same reference picture)
3. Condition determination 3 of the prediction block N0 (same reference list LX, different reference pictures)
4). Prediction block N0 condition decision 4 (different reference list LY, different reference picture)
5. Condition determination 1 of the prediction block N1 (same reference list LX, same reference picture)
6). Condition determination 2 of the prediction block N1 (different reference list LY, same reference picture)
7). Condition determination 3 of the prediction block N1 (same reference list LX, different reference pictures)
8). Prediction block N1 condition determination 4 (different reference list LY, different reference picture)
9. 9. Condition determination 1 of the prediction block N2 (same reference list LX, same reference picture), only the prediction block group adjacent on the upper side Condition determination 2 of the prediction block N2 (different reference list LY, the same reference picture),
10. Only the prediction block group adjacent on the upper side Condition determination 3 of the prediction block N2 (same reference list LX, different reference pictures),
Only the prediction block group adjacent on the upper side 12. Prediction block N2 condition determination 4 (different reference list LY, different reference picture)
, Only the upper adjacent prediction block group

According to the scan method 4, since the number of rounds of condition determination is at most one, the number of memory accesses to the encoded information of the prediction block when the implementation in hardware is taken into consideration is the scan method 1 and the scan method 2. Compared with the scanning method 3, the complexity is reduced.

Scanning method 5:
Similar to the scanning method 4, priority is given to the condition determination of the same prediction block, and four condition determinations are performed within one prediction block. If all the conditions are not met, the motion vector matching the condition is not included in the prediction block. It is determined that it does not exist, and the condition of the next prediction block is determined. However, in the condition determination in the prediction block, the scan method 4 gives priority to the same reference picture, but the scan method 5 gives priority to the same reference list.

Specifically, the condition determination is performed in the following priority order. (However, N is A or B)
1. Condition determination 1 of the prediction block N0 (same reference list LX, same reference picture)
2. Condition determination 3 of the prediction block N0 (same reference list LX, different reference pictures)
3. Prediction block N0 condition determination 2 (different reference list LY, same reference picture)
4). Prediction block N0 condition decision 4 (different reference list LY, different reference picture)
5. Condition determination 1 of the prediction block N1 (same reference list LX, same reference picture)
6). Condition determination 3 of the prediction block N1 (same reference list LX, different reference pictures)
7). Condition determination 2 of the prediction block N1 (different reference list LY, same reference picture)
8). Prediction block N1 condition determination 4 (different reference list LY, different reference picture)
9. 9. Condition determination 1 of the prediction block N2 (same reference list LX, same reference picture), only the prediction block group adjacent on the upper side Condition determination 3 of the prediction block N2 (same reference list LX, different reference pictures),
10. Only the prediction block group adjacent on the upper side Condition determination 2 of the prediction block N2 (different reference list LY, the same reference picture),
Only the prediction block group adjacent on the upper side 12. Prediction block N2 condition determination 4 (different reference list LY, different reference picture)
, Only the upper adjacent prediction block group

According to the scan method 5, the number of times of reference block reference lists can be reduced compared to the scan method 4, and the complexity is reduced by reducing the number of times of access to the memory and the amount of processing such as condition determination. can do. Similarly to scan method 4, since the number of rounds for condition determination is at most one, the number of memory accesses to the encoded information of the prediction block is the scan method 1, scan when considering implementation in hardware. Compared with Method 2 and Scan Method 3, the complexity is reduced.

Next, the motion vector predictor candidate registration unit 122 calculates the predicted motion vector candidate mvLXA.
, MvLXB, mvLXCol are stored in the predicted motion vector list mvpListLX.

Next, the motion vector redundancy candidate deletion unit 123 performs the motion vector vector list mvpL of LX.
Compare the motion vector values of each motion vector predictor stored in istLX, determine the motion vector candidates that have the same motion vector value, and have the same motion vector value The prediction motion vector list mvpListLX is updated by leaving one of the determined prediction motion vector candidates and deleting the others from the prediction motion vector list mvpListLX so that the prediction motion vector candidates do not overlap. However, when the defined final candidate number finalNumMVPCand is 1, this redundancy determination process can be omitted.

In the motion vector predictor candidate limit unit 124, the motion vector vector list mvpListLX of LX
The number of motion vector predictor candidates registered in is counted, and the number of motion vector predictor candidates numMVPCandLX of LX is set to the value of the counted number of candidates.

Further, in the motion vector predictor candidate number limiting unit 124, a motion vector list mv of LX is predicted.
The number of predicted motion vector candidates numMVPCandLX of LX registered in pListLX is limited to the number of final candidates finalNumMVPCand defined according to the size of the prediction block.

In the present embodiment, the final candidate number finalNumMVPCand according to the size of the prediction block
Is stipulated. This is because if the number of motion vector predictor candidates registered in the motion vector predictor list fluctuates according to the state of construction of the motion vector predictor list, the motion vector list on the decoding side must be constructed before the motion vector predictor list is constructed. This is because entropy decoding cannot be performed. Furthermore, if entropy decoding depends on the construction state of the motion vector predictor list including the motion vector candidate mvLXCol derived from the prediction block of the picture at different time, when an error occurs when decoding the encoded bit string of another picture The encoded bit string of the current picture is also affected by the error, and there is a problem that entropy decoding cannot be continued normally. Final candidate number finalNum depending on the size of the prediction block
If MVPCand is defined as a fixed number, the motion vector index can be entropy-decoded independently of the construction of the motion vector list, and even if an error occurs when decoding the coded bit stream of another picture, The entropy decoding of the coded bit stream of the current picture can be continued without being affected.

In the motion vector predictor candidate limit unit 124, the number of motion vector motion vector candidates numMVPCand
If LX is less than the specified final candidate number finalNumMVPCand, the number of motion vector predictor candidates num
Until the MVPCandLX reaches the same value as the final candidate number finalNumMVPCand, add motion vectors with a value of (0, 0) (both horizontal and vertical components are 0) to the predicted motion vector list mvpListLX to obtain the number of motion vector candidates Is limited to the specified value. In this case, duplicate (0,0
) May be added, but on the decoding side, the predicted motion vector is determined no matter what the predicted motion vector index is in the range from 0 to (the number of specified candidates −1). can do. On the other hand, if the number of predicted motion vectors numMVPCandLX of LX is larger than the final number of final candidates finalNumMVPCand, the predicted motion vector list mvpListLX
To delete all elements registered at an index greater than finalNumMVPCand-1.
The number of predicted motion vector candidates numMVPCandLX is set to the same value as the final candidate number finalNumMVPCand to limit the number of motion vector predictor candidates to a specified value. The updated motion vector predictor list mvpListLX includes the motion vector predictor candidate code amount calculation unit 125 and the motion vector predictor selection unit 1.
26.

On the other hand, the motion vector detection unit 102 in FIG. 1 performs LX (X = 0 or 1) for each prediction block.
Motion vector mvLX is detected. These motion vectors mvLX are supplied to the prediction motion vector candidate code amount calculation unit 125 together with the prediction motion vector candidates of the updated prediction motion vector list mvpListLX.

The motion vector predictor candidate code amount calculation unit 125 predicts each motion vector predictor candidate mvpListLX [i] stored in the motion vector list mvpListLX of LX (X = 0 or 1).
For each, a difference motion vector with the motion vector mvLX is calculated, and the amount of code when the difference motion vector is encoded is calculated and supplied to the predicted motion vector selection unit 126.

The motion vector predictor selection unit 126 selects a motion vector candidate mvpListLX [i] that has the smallest code amount for each motion vector predictor candidate from among the elements registered in the motion vector list mvpListLX of LX. Select as the predicted motion vector mvpLX. In the case where there are a plurality of motion vector predictor candidates having the smallest generated code amount in the motion vector predictor list mvpListLX, the motion vector predictor candidates represented by the index i in the motion vector list mvpListLX with a small number mvpListLX [i] is selected as the LX optimum predicted motion vector mvpLX. The selected predicted motion vector mvpLX is supplied to the motion vector subtraction unit 127. Further, the index i in the predicted motion vector list corresponding to the selected predicted motion vector mvpLX is output as a predicted motion vector index mvpIdxLX of LX.

Finally, the motion vector subtraction unit 127 calculates the LX differential motion vector mvdLX by subtracting the selected LX predicted motion vector mvpLX from the LX motion vector mvLX, and outputs the differential motion vector mvdLX.
mvdLX = mvLX-mvpLX

Returning to FIG. 1, the motion compensation prediction unit 105 refers to the image signal of the decoded picture stored in the decoded image memory 115, and the motion vector of LX (X = 0 or 1) supplied from the motion vector detection unit 102. Motion compensation is performed according to mvLX to obtain a predicted image signal, which is supplied to the prediction method determination unit 106.

The prediction method determination unit 106 determines a prediction method. The code amount and the coding distortion are calculated for each prediction mode, and the prediction block size and the prediction mode for the smallest generated code amount and coding distortion are determined. The LX differential motion vector mvdLX supplied from the motion vector subtraction unit 127 of the differential motion vector calculation unit 103 and the LX prediction motion vector index mvpIdxLX representing the prediction motion vector supplied from the prediction motion vector selection unit 126 are encoded. I,
The code amount of motion information is calculated. Further, the code amount of the prediction residual signal obtained by encoding the prediction residual signal between the prediction image signal supplied from the motion compensation prediction unit 105 and the image signal to be encoded supplied from the image memory 101 is calculated. The total generated code amount obtained by adding the code amount of the motion information and the code amount of the prediction residual signal is calculated and used as the first 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 coding distortion for each motion compensation, the prediction block size and the prediction mode that generate the least generated code amount and the coding distortion are determined. The motion vector prediction method described above is performed on the motion vector mvLX corresponding to the prediction mode of the determined prediction block size, and the index mvpIdxLX representing the prediction motion vector is a second syntax pattern in units of prediction blocks. It is encoded as the represented syntax element mvp_idx_lX [i]. The generated code amount calculated here is preferably a simulation of the encoding process, but can be approximated or approximated easily.

(Prediction of motion vector in decoding)
The operation of the motion vector prediction method according to the present invention in the video decoding device that decodes the encoded video bitstream based on the above-described syntax will be described.

When the motion vector prediction method according to the embodiment is performed, processing is performed by the motion vector calculation unit 204 of the video decoding device in FIG. FIG. 14 is a diagram illustrating a detailed configuration of the motion vector calculation unit 204 of the video decoding device of FIG. 2 corresponding to the video encoding device of the embodiment. A portion surrounded by a thick frame line in FIG. 14 indicates the motion vector calculation unit 204. Furthermore,
The part surrounded by the thick dotted line in the figure shows the operation part of the motion vector prediction method to be described later, and is also installed in the corresponding video encoding device in the same way, and the same determination result that is consistent between encoding and decoding So that you can get Hereinafter, a motion vector prediction method in decoding will be described with reference to FIG.

In the present embodiment, for the reason described on the encoding side, the final number of motion vector predictors finalNum on the decoding side as well as the encoding side according to the size of the prediction block to be decoded.
Set MVPCand. The motion vector calculation unit 204 sets finalNumMVPCand to a number smaller than the latter if the size of the prediction block of the luminance signal to be decoded is equal to or smaller than the specified size sizePUNumMVPCand, and if not, sets finalNumMVPCand to a number larger than the former. To do. In the present embodiment, the specified size sizePUNumMVPCand is set to 8x8, and the size of the prediction block of the luminance signal to be decoded is equal to or smaller than the specified size sizePUNumMVPCand.
lNumMVPCand is set to 1; otherwise, finalNumMVPCand is set to 2.

The motion vector calculation unit 204 includes a predicted motion vector candidate generation unit 221, a predicted motion vector candidate registration unit 222, a predicted motion vector redundancy candidate deletion unit 223, a predicted motion vector candidate number limit unit 224, a predicted motion vector selection unit 225, and a motion vector. An adder 226 is included.

In the motion vector calculation process in the motion vector calculation unit 204, a motion vector used in inter prediction is calculated for each of L0 and L1. Specifically, when the prediction mode PredMode of the decoding target block is inter prediction (MODE_INTER) and the inter prediction mode of the decoding target block is L0 prediction (Pred_L0), the prediction motion vector list mvpListL0 of L0 is calculated, and the prediction motion vector mvpL0 is selected, and a motion vector mvL0 of L0 is calculated. When the inter prediction mode of the decoding target block is L1 prediction (Pred_L1), the prediction motion vector list mvpLi of L1
stL1 is calculated, a predicted motion vector mvpL1 is selected, and a motion vector mvL1 of L1 is calculated. When the inter prediction mode of the decoding target block is bi-prediction (Pred_BI), L0 prediction and L1
Prediction is performed, L0 predicted motion vector list mvpListL0 is calculated, L0 predicted motion vector mvpL0 is selected, L0 motion vector mvL0 is calculated, L1 predicted motion vector list mvpListL1 is calculated, A predicted motion vector mvpL1 for L1 is calculated, and a motion vector mvL1 for L1 is calculated.
Similar to the encoding side, the motion vector calculation processing is performed for each of L0 and L1 on the decoding side, but both L0 and L1 are common processing. Therefore, in the following description, L0,
L1 is represented as a common LX. In the process of calculating the motion vector of L0, X is 0 and L
In the process of calculating the motion vector of 1, X is 1. When the information of the other list is referred to instead of LX during the process of calculating the LX motion vector, the other list is represented as LY.

The motion vector calculation unit 204 includes a motion vector predictor candidate generation unit 221, a motion vector predictor candidate registration unit 222, a motion vector predictor redundant candidate deletion unit 223, and a motion vector predictor candidate number restriction unit 224, which are differential motion vectors on the encoding side. It is specified that the motion vector predictor candidate generating unit 121, the motion vector predictor candidate registering unit 122, the motion vector predictor redundant candidate deleting unit 123, and the motion vector predictor candidate number limiting unit 124 in the calculation unit 103 perform the same operation. As a result, the same motion vector predictor candidate that is consistent between encoding and decoding can be obtained on the encoding side and the decoding side.

The motion vector predictor candidate generation unit 221 performs the same processing as that of the motion vector predictor candidate generation unit 121 on the encoding side in FIG. Decoded and recorded in the encoded information storage memory 209,
Coding motion vectors such as a decoded prediction block adjacent to the decoding target block in the same picture as the decoding target block and a decoded prediction block existing at the same position as or near the decoding target block in a different picture Read from the information storage memory 209. Prediction motion vector candidates mvLXA, mvLXB, and mvLXCol are generated for each prediction block group from the motion vectors of other decoded blocks read from the encoded information storage memory 209 and supplied to the motion vector predictor candidate registration unit 222. .

These predicted motion vector candidates mvLXA, mvLXB, and mvLXCol may be calculated by scaling according to the reference index. Since the motion vector predictor candidate generation unit 221 performs the same processing as that of the motion vector predictor candidate generation unit 121 on the encoding side in FIG. 13, the motion vector predictor candidate generation unit 121 on the encoding side in FIG. The condition determination of the scan methods 1, 2, 3, 4, and 5 for calculating the motion vector predictor can also be applied to the motion vector predictor candidate generation unit 221 and detailed description thereof is omitted here.

Next, the motion vector predictor candidate registration unit 222 performs the same processing as that of the motion vector predictor candidate registration unit 122 on the encoding side in FIG. Computed motion vector candidates mvLXA, mvLXB, mv
LXCol is stored in the predicted motion vector list mvpListLX of LX.

Next, the motion vector redundancy candidate deletion unit 223 performs the same process as the motion vector redundancy candidate deletion unit 123 on the encoding side in FIG. LX predicted motion vector list mvpListLX
Of the motion vector predictor candidates that have the same motion vector value, and leave one of the motion vector predictor candidates determined to have the same motion vector value. The predicted motion vector list mvpListLX is deleted from the predicted motion vector list mvpListLX so that the predicted motion vector candidates do not overlap, and the predicted motion vector list mvpListLX is updated. However, when the defined final candidate number finalNumMVPCand is 1, this redundancy determination process can be omitted.

Next, the motion vector predictor candidate number limiting unit 224 performs the same processing as the motion vector predictor candidate number limiting unit 124 on the encoding side in FIG. In the motion vector predictor candidate number limiting unit 224, the number of elements registered in the motion vector predictor list mvpListLX is counted, and the motion vector candidate number numMVPCandLX of LX is set to the value of the counted candidate number.

Further, in the motion vector predictor candidate number limiting unit 224, the number of motion vector predictor candidates numMVPC registered in the motion vector predictor list mvpListLX for the reason described on the encoding side.
andLX is limited to the final candidate number finalNumMVPCand defined according to the size of the prediction block. Final number of predicted motion vector candidates numMVPCandLX for which LX is defined finalNumMVPCand
If it is smaller, a motion vector having a value of (0, 0) is predicted motion vector list mvpLis until the predicted motion vector candidate number numMVPCandLX becomes the same value as the final candidate number finalNumMVPCand.
By adding to tLX, the number of motion vector predictor candidates is limited to a specified value. In this case, a motion vector having a value of (0, 0) may be added in duplicate, but on the decoding side, any value within the range of the predicted motion vector index from 0 to the specified value −1 is taken. The predicted motion vector can be determined. On the other hand, if the number of predicted motion vectors numMVPCandLX of LX is larger than the final number of final candidates finalNumMVPCand, the predicted motion vector list mvpListLX
To delete all elements registered at an index greater than finalNumMVPCand-1.
The number of predicted motion vector candidates numMVPCandLX is set to the same value as the final candidate number finalNumMVPCand to limit the number of motion vector predictor candidates to a specified value. The updated motion vector predictor list mvpListLX is supplied to the motion vector predictor selection unit 225.

On the other hand, LX (X = 0) for each prediction block decoded by the first encoded bit string decoding unit 202.
Alternatively, the difference motion vector mvdLX of 1) is supplied to the motion vector addition unit 226. The predicted motion vector index mvpIdxLX of the LX predicted motion vector decoded by the first encoded bit string decoding unit 202 is supplied to the predicted motion vector selection unit 225. However, when the defined final candidate number finalNumMVPCand is 1, the predicted motion vector index mvpIdxLX of the LX predicted motion vector is not encoded and is not supplied to the predicted motion vector selection unit 225.

The motion vector predictor selection unit 225 receives the L decoded by the first encoded bit string decoding unit 202.
X predicted motion vector index mvpIdxLX is supplied and supplied index mvpIdx
Predictive motion vector candidates mvpListLX [mvpIdxLX] corresponding to LX are converted into LX predicted motion vectors mvp.
Extracted from the motion vector predictor list mvpListLX as LX. However, when the defined final candidate number finalNumMVPCand is 1, the only motion vector candidate mvpListLX [0] for which the index i of the motion vector predictor list mvpListLX is registered as 0 is extracted. The supplied motion vector predictor candidate is supplied to the motion vector adding unit 226 as a motion vector predictor mvpLX.

Finally, the motion vector addition unit 226 calculates the LX motion vector mv by adding the LX differential motion vector mvdLX and the LX prediction motion vector mvpLX that are supplied after being decoded by the first encoded bit string decoding unit 202. And outputs a motion vector mvLX.
mvLX = mvpLX + mvdLX

As described above, the LX motion vector mvLX is calculated for each prediction block. A predicted image signal is generated by motion compensation using this motion vector, and is added to the decoded prediction residual signal to generate a decoded image signal.

Processing procedures of the difference motion vector calculation unit 103 of the moving image encoding device and the motion vector calculation unit 204 of the moving image decoding device will be described with reference to flowcharts of FIGS. 15 and 16, respectively. FIG. 15 is a flowchart showing a difference motion vector calculation processing procedure by the moving image encoding device, and FIG. 16 is a flowchart showing a motion vector calculation processing procedure by the moving image decoding device.

The difference motion vector calculation processing procedure on the encoding side will be described with reference to FIG. On the encoding side, first, the differential motion vector calculation unit 103 performs the final candidate number finalN of predicted motion vector candidates.
umMVCand is set (S100). FIG. 17 shows the detailed processing procedure of step S100.
This will be described later with reference to the flowchart.

Subsequently, the differential motion vector calculation unit 103 calculates the differential motion vector of the motion vector used in the inter prediction selected in the encoding target block for each of L0 and L1 (S1).
01-S106). Specifically, when the prediction mode PredMode of the encoding target block is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0), a prediction motion vector list mvpListL0 of L0 is calculated and a prediction motion vector mvpL0 is selected. Then, the differential motion vector mvdL0 of the motion vector mvL0 of L0 is calculated. When the inter prediction mode of the encoding target block is L1 prediction (Pred_L1), the prediction motion vector list mvpListL1 of L1 is calculated,
The predicted motion vector mvpL1 is selected, and a differential motion vector mvdL1 of the L1 motion vector mvL1 is calculated. When the inter prediction mode of the encoding target block is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, and a prediction motion vector list mvpListL0 of L0 is calculated.
Motion vector mvpL0 of L1, motion vector mvdL0 of motion vector mvL0 of L0 is calculated, motion vector list mvpListL1 of motion vector L1 is computed, motion vector motion vector mvpL1 of motion L1 is computed, motion vector of motion L1 A difference motion vector mvdL1 of mvL1 is calculated.

Difference motion vector calculation processing is performed for each of L0 and L1, but both L0 and L1 are common processing. Therefore, in the following description, L0 and L1 are represented as a common LX. In the process of calculating the differential motion vector of L0, X is 0, and in the process of calculating the differential motion vector of L1, X is 1. In addition, during the process of calculating the LX differential motion vector,
When referring to the information of the other list instead of LX, the other list is represented as LY.

When the LX differential motion vector mvdLX is calculated (YES in S102), the LX predicted motion vector candidates are calculated to construct the LX predicted motion vector list mvpListLX (S10).
3). The motion vector predictor candidate generation unit 121 in the motion vector difference calculation unit 103 calculates a plurality of motion vector predictor candidates, and the motion vector predictor candidate registration unit 122 calculates the motion vector predictor candidates calculated in the motion vector predictor list mvpListLX. In addition, the motion vector redundancy candidate deletion unit 123 deletes unnecessary motion vector predictor candidates, and the motion vector predictor candidate number limiting unit 124 registers the number of motion vector motion vector candidates numMVPCandLX in the motion vector list mvpListLX. Is set and the predicted motion vector list mvpListLX is constructed by limiting the number of predicted motion vector candidates numMVPCandLX of LX registered in the predicted motion vector list mvpListLX to the final number of final candidates finalNumMVPCand. Step S103
The detailed processing procedure will be described later with reference to the flowchart of FIG.

Subsequently, the motion vector predictor candidate code amount calculation unit 125 and the motion vector predictor selection unit 12
6, the LX predicted motion vector mvpLX is selected from the LX predicted motion vector list mvpListLX (S104). First, the motion vector mvLX and the motion vector predictor candidate m stored in the motion vector predictor list mvpListLX are calculated by the motion vector predictor candidate code amount calculation unit 125.
Each difference motion vector, which is a difference from vpListLX [i], is calculated, a code amount when the difference motion vector is encoded is calculated for each element of the prediction motion vector list mvpListLX, and the prediction motion vector selection unit 126 Among the elements registered in the prediction motion vector list mvpListLX, the prediction motion vector candidate mv having the smallest code amount for each prediction motion vector candidate
pListLX [i] is selected as the predicted motion vector mvpLX. Predicted motion vector list mvpListLX
When there are a plurality of motion vector predictor candidates that have the smallest generated code amount, the motion vector candidate mvpListLX [i] represented by a smaller index i in the motion vector list mvpListLX Select as the optimal prediction motion vector mvpLX.

Subsequently, the motion vector subtraction unit 127 calculates an LX differential motion vector mvdLX by subtracting the LX predicted motion vector mvpLX selected from the LX motion vector mvLX (
S105).
mvdLX = mvLX-mvpLX

Next, the decoding-side motion vector calculation processing procedure will be described with reference to FIG. On the decryption side,
The motion vector calculation unit 204 calculates a motion vector used for inter prediction for each of L0 and L1 (S201 to S206). Specifically, the prediction mode PredMo of the decoding target block
When de is inter prediction (MODE_INTER) and the inter prediction mode of the decoding target block is L0 prediction (Pred_L0), a prediction motion vector list mvpListL0 of L0 is calculated, a prediction motion vector mvpL0 is selected, and a motion vector mvL0 of L0 is selected. Is calculated. When the inter prediction mode of the decoding target block is L1 prediction (Pred_L1), the L1 predicted motion vector list mvpListL1 is calculated, the predicted motion vector mvpL1 is selected, and the L1 motion vector mvL1 is calculated. When the inter prediction mode of the decoding target block is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, the L0 prediction motion vector list mvpListL0 is calculated, the L0 prediction motion vector mvpL0 is selected, and the L0 prediction motion vector list is selected. The motion vector mvL0 is calculated, the L1 predicted motion vector list mvpListL1 is calculated, the L1 predicted motion vector mvpL1 is calculated, and the L1 motion vector mvL1 is calculated.

Similar to the encoding side, the motion vector calculation processing is performed for each of L0 and L1 on the decoding side, but both L0 and L1 are common processing. Therefore, in the following description, L0,
L1 is represented as a common LX. In the process of calculating the motion vector of L0, X is 0 and L
In the process of calculating the motion vector of 1, X is 1. When the information of the other list is referred to instead of LX during the process of calculating the LX motion vector, the other list is represented as LY.

When calculating an LX motion vector mvLX (YES in S202), an LX predicted motion vector candidate is calculated to construct an LX predicted motion vector list mvpListLX (S203).
In the motion vector calculation unit 204, a motion vector predictor candidate generation unit 221 calculates a plurality of motion vector predictor candidates, and a motion vector predictor candidate registration unit 222 predicts a motion vector list mv.
Predicted motion vector candidates calculated in pListLX are added, unnecessary motion vector redundancy candidate deletion unit 223 deletes unnecessary prediction motion vector candidates, and motion vector predictor candidate number limiting unit 224
The number of predicted motion vector candidates for LX registered in the predicted motion vector list mvpListLX at num
The predicted motion vector list mvpListLX is constructed by limiting the number of predicted motion vector candidates numMVPCandLX of LX registered in the predicted motion vector list mvpListLX to the specified final candidate number finalNumMVPCand. The detailed processing procedure of step S203 will be described later with reference to the flowchart of FIG.

Subsequently, the motion vector predictor selection unit 225 selects the first motion vector from the motion vector list mvpListLX.
A motion vector predictor mvp from which a motion vector predictor candidate mvpListLX [mvpIdxLX] corresponding to the index mvpIdxLX of the motion vector predictor decoded by the encoded bit string decoding unit 202 is selected.
Take out as LX (S204). However, when the maximum number of candidates finalNumCandLX is 1, only one motion vector candidate mvpListLX [0 registered in the motion vector predictor list mvpListLX
] Is extracted as the selected predicted motion vector mvpLX.

Subsequently, the motion vector addition unit 226 calculates the LX motion vector mvLX by adding the LX differential motion vector mvdLX decoded and supplied by the first encoded bit string decoding unit 202 and the LX predicted motion vector mvpLX. (S205 in FIG. 16).
mvLX = mvpLX + mvdLX

Next, a procedure for setting the final number of motion vector predictor common in S100 of FIG. 15 and S200 of FIG. 16 will be described in detail.

The motion vector predictor candidate number limiting unit 124 and the motion vector predictor candidate number limiting unit 224 have a final motion vector predictor candidate fina according to the size of the prediction block to be encoded or decoded.
Set lNumMVPCand.

  FIG. 17 is a flowchart showing the final candidate number setting processing procedure of the motion vector predictor.

First, the size of a prediction block to be encoded or decoded is obtained (S401). When the size of the prediction block to be encoded or decoded is equal to or smaller than the specified size sizePUNumMVPCand (S4
02, YES), finalNumMVPCand is set to a number smaller than the latter (S403). Otherwise, finalNumMVPCand is set to a number greater than the former (S404). In this embodiment, the specified size sizePUNumMVPCand is 8x8, and the size of the prediction block of the luminance signal to be encoded or decoded is smaller than the specified size sizePUNumMVPCand, finalN
Set umMVPCand to 1, otherwise set finalNumMVPCand to 2. The prescribed size sizePUNumMVPCand may be a fixed value, or may be set by preparing a syntax element for each sequence, picture, or slice. Also 8x4 and 4x8 etc.
If the values obtained by multiplying the width and height are the same size, they are considered to be the same size. That is, the size to be specified
When sizePUNumMVPCand is set to 8x4, it is considered that 4x8 is also set. In step S402, the size sizePUNu defined by the size of the prediction block to be encoded or decoded is defined.
If less than mMVPCand, finalNumMVPCand may be set to a number smaller than the latter, otherwise finalNumMVPCand may be set to a number greater than the former.

Next, a procedure for derivation of a prediction motion vector candidate common to S103 in FIG. 15 and S203 in FIG. 16 and a prediction motion vector list construction process will be described in detail with reference to the flowchart in FIG.

(Motion vector prediction method)
FIG. 18 shows motion vector predictor candidate generating units 121 and 221 having a function common to the motion vector calculating unit 103 of the video encoding device and the motion vector calculating unit 204 of the video decoding device, and a motion vector predictor candidate registration unit 122. And 222, and the motion vector redundancy candidate deletion units 123 and 223 and the motion vector predictor candidate number limiting units 124 and 224 are flowcharts.

The motion vector predictor candidate generation units 121 and 221 derive motion vector predictor candidates from the prediction block adjacent on the left side, a flag availableFlagLXA indicating whether the motion vector candidate of the prediction block adjacent on the left side can be used, and motion A vector mvLXA, a reference index refIdxA, and a list ListA are derived (S301 in FIG. 18). Note that X is 0 when L0 and X is 1 when L1 (the same applies hereinafter). Subsequently, the motion vector predictor candidate generation unit 121
And 221 derive a prediction motion vector candidate from the prediction block adjacent on the upper side, and a flag avai indicating whether the prediction motion vector candidate of the prediction block adjacent on the upper side is available
A lableFlagLXB, a motion vector mvLXB, a reference index refIdxB, and a list ListB are derived (S302 in FIG. 18). The processes in steps S301 and S302 in FIG. 18 are common except that the positions and numbers of adjacent blocks to be referenced are different, and a flag availableFlagLXN indicating whether or not a motion vector candidate of a predicted block can be used, and a motion vector mvLXN, reference A common derivation processing procedure for deriving indexes refIdxN and ListN (N is A or B, the same applies hereinafter) will be described in detail later with reference to the flowcharts of FIGS.

Subsequently, the motion vector predictor candidate generation units 121 and 221 derive motion vector predictor candidates from the prediction blocks of the pictures at different times, and indicate whether the motion vector predictor candidates of the motion pictures at different times can be used. A flag availableFlagLXCol, a motion vector mvLXCol, a reference index refIdxCol, and a list ListCol are derived (S303 in FIG. 18). The derivation processing procedure of step S303 will be described in detail later with reference to the flowcharts of FIGS.

Subsequently, the motion vector predictor candidate registration units 122 and 222 perform the motion vector predictor list mvpL.
istLX is created, and prediction vector candidates mvLXA, mvLXB, and mvLXCol for each LX are added (S304 in FIG. 18). The registration processing procedure in step S304 will be described in detail later using the flowchart in FIG.

Subsequently, the motion vector redundancy candidate deletion units 123 and 223 perform the motion vector predictor list.
In mvpListLX, when multiple motion vector candidates have the same value or close values,
It is determined that the candidate is a redundant motion vector, and the redundant motion vector candidate is removed except for the motion vector candidate having the smallest order, that is, the smallest index i (S305 in FIG. 18).
. The deletion processing procedure in step S305 will be described in detail later using the flowchart of FIG.

Subsequently, the motion vector predictor candidate number limiting units 124 and 224 perform the motion vector predictor list mv.
The number of elements added in pListLX is counted, and the number of predicted motion vector candidates n is LX.
The number of predicted motion vector candidates numMVPCandLX of LX registered in the predicted motion vector list mvpListLX, which is set to umMVPCandLX, is limited to the specified final candidate number finalNumMVPCand.
(S306 in FIG. 18). The restriction process procedure of step S306 will be described in detail later with reference to the flowchart of FIG.

A procedure for deriving motion vector predictor candidates from prediction blocks adjacent to the left or upper side of S301 and S302 in FIG. 18 will be described in detail.

As shown in FIGS. 5, 6, 7, and 8, a prediction block (in FIG. 5, FIG. 6, FIG. 7, and FIG. 8) that is defined for motion compensation within a coding block in the same picture. A motion vector predictor candidate is derived from surrounding prediction blocks adjacent to the processing target prediction block.

A motion vector predictor candidate is a prediction block A adjacent to the left side of the prediction block to be processed.
k (k = 0, 1), that is, a prediction block group A composed of A0 and A1, and a prediction block Bk (k = 0, 1, 2) adjacent thereto, that is, a prediction composed of B0, B1, and B2. A candidate motion vector predictor is selected from each block group B.

Next, a method for deriving prediction motion vector candidates from the prediction block group N adjacent on the left and upper sides, which is the processing procedure of S301 and S302 in FIG. 18, will be described. FIG.
9 is a flowchart showing the predicted motion vector candidate derivation processing procedure of S301 and S302 of FIG. Subscript X contains 0 or 1 representing the reference list, and N represents A (left side) or B (upper side) representing the area of the adjacent prediction block group.

Deriving motion vector predictor candidates from the left prediction block (S301 in FIG. 18)
, A0, A adjacent to the left side of the prediction block to be encoded or decoded as N as A in FIG.
In order to derive a motion vector predictor candidate from one prediction block and a motion vector predictor candidate from the upper prediction block (S302 in FIG. 18), N is B in FIG. 19, and B0, B1, and B2 are adjacent to the upper side. Prediction motion vector candidates are calculated from the prediction block by the following procedure.

First, a prediction block adjacent to a prediction block to be encoded or decoded is specified, and each prediction block Nk (k = 0, 1, 2, where 2 is only the upper prediction block group)
Is available, the encoded information stored in the encoded information storage memory 114 or the encoded information storage memory 209 is acquired. The encoding information of the adjacent prediction block Nk acquired here is a flag predFlagLX [xNk] [y indicating whether to use the prediction modes PredMode and LX.
Nk], LX reference index refIdxLX [xNk] [yNk], LX motion vector mvLX [xNk] [yNk
]. In the case of a prediction block group (N = A) adjacent to the left side of the prediction block to be encoded or decoded (YES in S1101), the prediction block A0 adjacent to the lower left and the prediction block A1 adjacent to the left are specified and encoded. Information is acquired (S1102, S1103), and in the case of a prediction block group (N = B) adjacent to the upper side of the prediction block to be encoded or decoded (NO in S1101), adjacent to the prediction block B0 adjacent to the upper right Coding information is acquired by specifying the prediction block B1 to be predicted and the prediction block B2 adjacent to the upper left (S1104,
S1105, S1106). It can be used when the adjacent prediction block Nk is located inside the slice including the prediction block to be encoded or decoded, and cannot be used when located outside.

Next, a flag indicating whether or not a prediction motion vector is selected from the prediction block group N
The availableFlagLXN is 0, and the motion vector mvLXN representing the prediction block group N is (0,
0) (S1107).

Subsequently, a motion vector predictor candidate that matches Condition Determination 1 or Condition Determination 2 described above is derived (S1108). Prediction block N0 of prediction block group N (N is A or B)
, N1, N2 (N2 is only the upper adjacent prediction block group B), the reference list LX that is the same as the reference list LX that is the current target in the encoding or decoding target prediction block, or the encoding or decoding target prediction block Reference list LY opposite to the current target reference list LX (Y =! X: When the current target reference list is L0, the opposite reference list is L1, and when the current target reference list is L1, the opposite The reference list is searched for a prediction block having the same reference picture motion vector in L0), and the motion vector is set as a motion vector predictor candidate.

FIG. 20 is a flowchart showing the derivation process procedure of step S1108 of FIG. For the adjacent prediction block Nk (k = 0, 1, 2, where 2 is only the upper adjacent prediction block group), the following processing is performed in the order of k, 0, 1, and 2 (S1201 to S120).
1207). When N is A, the order is A0, A1 from bottom to top. When N is B, B is from right to left.
The following processing is performed in the order of 0, B1, and B2, respectively.

When the adjacent prediction block Nk can be used and the prediction mode PredMode of the prediction block Nk is not intra (MODE_INTRA) (YES in S1202), the condition determination of the above-described condition determination 1 is performed (S1203). Flag pr indicating whether or not to use LX of adjacent prediction block Nk
edFlagLX [xNk] [yNk] is 1, that is, the adjacent prediction block Nk is inter-predicted using the same LX motion vector as the calculation target, and the LX reference index refIdxLX [xNk] [yNk] of the adjacent prediction block Nk ] And the index refIdxLX of the prediction block to be processed are the same,
That is, when the adjacent prediction block Nk is inter-predicted using the same reference picture in LX prediction (YES in S1203), the process proceeds to step S1204, and otherwise (S1
203 NO), the condition determination of step S1205 is performed.

When step S1203 is YES, the flag availableFlagLXN is set to 1, the prediction motion vector mvLXN of the prediction block group N is set to the same value as the LX motion vector mvLX [xNk] [yNk] of the adjacent prediction block Nk, and prediction is performed. Reference index of block group N
refIdxN is set to the same value as the LX reference index refIdxLX [xNk] [yNk] of the adjacent prediction block Nk, and the reference list ListN of the prediction block group N is set to LX (S12
04) The prediction motion vector candidate calculation process is terminated.

On the other hand, if step S1203 is NO, the condition determination of condition determination 2 described above is performed (S12).
05). A flag predFlagLY indicating whether to use LY of the adjacent prediction block Nk is 1
That is, the adjacent prediction block Nk is inter-predicted using a motion vector of LY different from the calculation target, and the POC of the reference picture of the reference list LY opposite to the reference list LX that is the current target of the adjacent prediction block Nk If the POC of the LX reference picture of the prediction block to be processed is the same, that is, if adjacent prediction blocks Nk are inter-predicted using the same reference picture in LY prediction (YES in S1205), the process proceeds to step S1206,
The flag availableFlagLXN is set to 1 and the prediction motion vector mv of the prediction block group N
LXN is set to the same value as the LY motion vector mvLY [xNk] [yNk] of the adjacent prediction block Nk, and the reference index refIdxN of the prediction block group N is the LY reference index refIdxLY [xNk] [ yNk] is set to the same value, the reference list ListN of the prediction block group N is set to LY (S1206), and the motion vector predictor candidate calculation process ends.

If these conditions are not met, that is, if NO in S1203 or NO in S1205, k is incremented by 1, and the next adjacent prediction block processing (S1201 to S1207) is performed.
The process is repeated until ailableFlagLXN becomes 1 or the processing of the adjacent block A1 or B2 ends.

Subsequently, returning to the flowchart of FIG. 19, when availableFlagLXN is 0 (YES in S1109), that is, if a motion vector predictor candidate cannot be calculated in step S1108,
A motion vector predictor candidate that matches the condition determination 3 or the condition determination 4 is calculated (S11).
10). Predicted block group N (N is A or B) adjacent blocks N0, N1, N2 (
N2 is only the upper adjacent prediction block group B), and the reference list LX that is the same as the reference list LX that is the current target in the encoding or decoding target prediction block, or the reference that is the current target in the encoding or decoding target prediction block Reference list LY opposite to list LX (Y =
! X: When the current target reference list is L0, the opposite reference list is L1, and when the current target reference list is L1, the opposite reference list is L0). The motion vector is searched for as a predicted motion vector candidate.

FIG. 21 is a flowchart showing the derivation process procedure of step S1110 of FIG. For the adjacent prediction block Nk (k = 0, 1, 2, where 2 is only the upper adjacent prediction block group), the following processing is performed in the order of k being 0, 1, 2 (S1301 to S130).
1307). When N is A, the order is A0, A1 from bottom to top. When N is B, B is from right to left.
The following processing is performed in the order of 0, B1, and B2, respectively.

When the adjacent prediction block Nk can be used and the prediction mode PredMode of the prediction block Nk is not intra (MODE_INTRA) (YES in S1302), the condition determination of the above-described condition determination 3 is performed (S1303). Flag pr indicating whether or not to use LX of adjacent prediction block Nk
If edFlagLX [xNk] [yNk] is 1, that is, if an adjacent prediction block Nk is inter-predicted using the same LX motion vector as the calculation target, the process proceeds to step S1304; otherwise (NO in S1303), step The condition is determined in S1305.

When step S1303 is YES, the flag availableFlagLXN is set to 1, and the motion vector mvLX [xNk] [y of the LX of the prediction block Nk to which mvLXN of the prediction block group N is adjacent is set.
Nk], the reference index refIdxN of the prediction block group N is set to the same value as the LX reference index refIdxLX [xNk] [yNk] of the adjacent prediction block Nk, and the reference list ListN of the prediction block group N Is set to LX (S1304), step S
Proceed to 1308.

When step S1303 is NO, the condition determination of the above-described condition determination 4 is performed (S1305).
. When the flag predFlagLY indicating whether to use the LY of the adjacent prediction block Nk is 1, that is, when the adjacent prediction block Nk is inter-predicted using a motion vector of LY different from the calculation target (YES in S1305), the flag availableFlagLXN Is set to 1, the prediction motion vector mvLXN of the prediction block group N is set to the same value as the LY motion vector mvLY [xNk] [yNk] of the adjacent prediction block Nk, and the prediction motion vector mvLXN of the prediction block group N is Prediction block N which is set to the same value as the LY motion vector mvLY [xNk] [yNk] of the adjacent prediction block Nk and the reference index refIdxN of the prediction block group N is adjacent
The LY reference index refIdxLY [xNk] [yNk] of k is set to the same value, the reference list ListN of the prediction block group N is set to LY (S1306), and the process proceeds to step S1308.

On the other hand, if these conditions are not met (NO in S1303 or NO in S1305), k is incremented by 1, and the next adjacent prediction block is processed (S1301 to S1307), and availableFlagLXN becomes 1, The process is repeated until the processing of the adjacent block A1 or B2 is completed, and the process proceeds to step S1308.

Subsequently, when availableFlagLXN is 1 (YES in S1308), mvLXN is scaled (S1309). The scaling calculation processing procedure of the spatial prediction motion vector candidate in step S1309 will be described with reference to FIGS.

FIG. 22 is a flowchart showing the motion vector scaling calculation processing procedure in step S1309 in FIG.

List of adjacent prediction blocks ListN from the POC of the current encoding or decoding target picture
The inter-picture distance td is calculated by subtracting the POC of the reference picture referenced by (S1601).
). Note that the list of adjacent prediction blocks ListN rather than the current encoding or decoding target picture
If the reference picture referred to in FIG. 1 is earlier in the display order, the inter-picture distance td is a positive value, and the reference picture referenced in the reference list ListN of the adjacent prediction block is more current than the current encoding or decoding target picture. When the display order is later, the inter-picture distance td becomes a negative value.
td = POC of current encoding or decoding target picture—POC of reference picture referenced in reference list ListN of adjacent prediction block

The inter-picture distance tb is calculated by subtracting the POC of the reference picture referenced by the current encoding or decoding target picture list LX from the POC of the current encoding or decoding target picture (S1602). If the reference picture referenced in the list LX of the current encoding or decoding target picture is earlier than the current encoding or decoding target picture in the display order, the inter-picture distance tb is a positive value. When the reference picture referred to in the encoding or decoding target picture list LX is later in the display order, the inter-picture distance tb is a negative value.
tb = POC of the current encoding or decoding target picture-POC of the reference picture referenced in the reference list LX of the current encoding or decoding target picture

Subsequently, scaling operation processing is performed by multiplying mvLXN by the scaling coefficient tb / td according to the following equation (S1603) to obtain a scaled motion vector mvLXN.
mvLXN = tb / td * mvLXN

Further, an example in which the scaling operation in step S1603 is performed with integer precision arithmetic is shown in FIG.
3 shows. The processing of steps S1604 to S1606 in FIG. 23 is the same as step S16 in FIG.
This corresponds to the process No. 03.

First, as in the flowchart of FIG. 22, the inter-picture distance td and the inter-picture distance tb are calculated (S1601, S1602).

Subsequently, the variable tx is calculated by the following equation (S1604).
tx = (16384 + Abs (td / 2)) / td

Subsequently, the scaling coefficient DistScaleFactor is calculated by the following equation (S1605).
DistScaleFactor = (tb * tx + 32) >> 6

Subsequently, a scaled motion vector mvLXN is obtained by the following equation (S1606).
mvLXN = ClipMv (Sign (DistScaleFactor * mvLXN) * ((Abs (DistScaleFactor * mv
LXN) + 127) >> 8))

Next, a method of deriving motion vector predictor candidates from the prediction blocks of pictures at different times in S303 in FIG. 18 will be described in detail. FIG. 24 is a flowchart for explaining the prediction motion vector candidate derivation processing procedure in step S303 in FIG.

First, a picture colPic at a different time is calculated based on slice_type and collocated_from_l0_flag (S2101 in FIG. 24).

FIG. 25 is a flowchart for explaining the procedure for deriving the picture colPic at different times in step S2101 of FIG. slice_type is B and the above flag collocated_from_l0_f
When lag is 0 (YES in S2201 in FIG. 25, YES in S2202), RefPicList1 [0]
That is, a picture co at a time when a picture with a reference index 0 in the reference list L1 is different
lPic (S2203 in FIG. 25). Otherwise, ie the aforementioned flag collocated
When _from_l0_flag is 1 (NO in S2201 in FIG. 25, NO in S2202, S2204
NO), RefPicList0 [0], that is, the picture colPic at a different time is the picture with the reference index 0 in the reference list L0 (S2205 in FIG. 25).

Next, returning to the flowchart of FIG. 24, a prediction block colPU at a different time is calculated, and encoded information is acquired (S2102 of FIG. 24).

FIG. 26 shows a prediction block co of a picture colPic at different times in step S2102 of FIG.
It is a flowchart explaining the lPU derivation processing procedure.

First, a prediction block located at the lower right (outside) of the same position as the processing target prediction block in the picture colPic at different times is set as a prediction block colPU at different times (S in FIG. 26).
2301). This prediction block corresponds to the prediction block T0 in FIG.

Next, encoding information of the prediction block colPU at different times is acquired (S2302 in FIG. 26).
). If PredMode of the prediction block colPU at different time is MODE_INTRA or cannot be used (S2303 and S2304 in FIG. 26), the prediction block located at the upper left center of the same position as the processing target prediction block in the picture colPic at different time is different in time. The prediction block colPU is reset (S2305 in FIG. 26). This prediction block corresponds to the prediction block T1 in FIG.

Next, returning to the flowchart of FIG. 24, the LX prediction motion vector mvLXCol calculated from the prediction block of another picture at the same position as the prediction block to be encoded or decoded and the encoding information of the reference list LX of the prediction block group Col Flag availableF indicating whether or not is valid
lagLXCol is calculated (S2103 in FIG. 24).

FIG. 27 is a flowchart illustrating the inter prediction information derivation process in step S2103 of FIG.

When PredMode of prediction block colPU at different time is MODE_INTRA or not available (Fig. 2
7 S2401 NO, S2402 NO), availableFlagLXCol is 0, mvLXCol is (0
, 0) (S2403, S2404 in FIG. 27), the process is terminated.

When the prediction block colPU is available and PredMode is not MODE_INTRA (S240 in FIG. 27)
1 YES, S2402 YES), mvCol and refIdxCol are calculated in the following procedure.

Flag PredFlagL0 [xPCo indicating whether L0 prediction of prediction block colPU is used
When l] [yPCol] is 0 (YES in S2405 in FIG. 27), since the prediction mode of the prediction block colPU is Pred_L1, the motion vector mvCol is MvL1 [xPCol] [yPCol, which is the L1 motion vector of the prediction block colPU. ] Is set to the same value as in FIG. 27 (S2406 in FIG. 27) and the reference index
refIdxCol is set to the same value as the reference index RefIdxL1 [xPCol] [yPCol] of L1 (FIG. 2
7 (S2407), the list ListCol is set to L1 (S2408 in FIG. 27).

On the other hand, when the L0 prediction flag PredFlagL0 [xPCol] [yPCol] of the prediction block colPU is not 0 (NO in S2405 in FIG. 27), the L1 prediction flag PredFlagL1 [xPCol] of the prediction block colPU
Determine whether [yPCol] is 0. L1 prediction flag PredFlagL1 [xPCol of prediction block colPU
] [yPCol] is 0 (YES in S2409 in FIG. 27), the motion vector mvCol is set to the same value as MvL0 [xPCol] [yPCol], which is the L0 motion vector of the prediction block colPU (S2410 in FIG. 27). , Reference index RefIdxL0 [xPCol] [y with reference index refIdxCol being L0
PCol] is set to the same value (S2411 in FIG. 27), and the list ListCol is set to L0 (S2412 in FIG. 27).

When both 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 (N in S2405 in FIG. 27)
O, NO in S2409), the inter prediction mode of the prediction block colPU is bi-prediction (Pred_BI)
Therefore, one of the two motion vectors L0 and L1 is selected (S241 in FIG. 27).
3).

FIG. 28 is a flowchart illustrating a procedure for deriving inter prediction information of a prediction block when the inter prediction mode of the prediction block colPU is bi-prediction (Pred_BI).

First, it is determined whether the POC of all pictures registered in all reference lists is smaller than the POC of the current encoding or decoding target picture (S2501), and L0 and all reference lists of the prediction block colPU are determined. When the POC of all pictures registered in L1 is smaller than the POC of the current encoding or decoding target picture (S2501)
YES), when X is 0, that is, when a prediction vector candidate of the motion vector L0 of the prediction block to be encoded or decoded is calculated (YES in S2502), L of the prediction block colPU
When the inter prediction information of 0 is selected and X is 1, that is, when the prediction vector candidate of the motion vector of L1 of the prediction block to be encoded or decoded is calculated (NO in S2502), L1 of the prediction block colPU Select the inter prediction information. On the other hand, when at least one of the POCs of the pictures registered in all reference lists L0 and L1 of the prediction block colPU is larger than the POC of the current encoding or decoding target picture (NO in S2501),
When the flag collocated_from_l0_flag is 0 (YES in S2503), the inter prediction information on the L0 side of the prediction block colPU is selected, and when the flag collocated_from_l0_flag is 1 (S
NO of 2503), the inter prediction information of L1 of the prediction block colPU is selected.

When selecting inter prediction information for the L0 of the prediction block colPU (YE in S2502)
S, YES in S2503), the motion vector mvCol is set to the same value as MvL0 [xPCol] [yPCol] (S2504), the reference index refIdxCol is set to the same value as RefIdxL0 [xPCol] [yPCol] (S2505), list ListCol is set to L0 (S2506).

When selecting inter prediction information for the L1 of the prediction block colPU (NO in S2502)
, S2503 NO), the motion vector mvCol is set to the same value as MvL1 [xPCol] [yPCol] (
In step S2507, the reference index refIdxCol is set to the same value as RefIdxL1 [xPCol] [yPCol] (S2508), and the list ListCol is set to L1 (S2509).

Returning to FIG. 27, if inter prediction information can be acquired from the prediction block colPU, availableFlag
LXCol is set to 1 (S2414 in FIG. 27).

Next, returning to the flowchart in FIG. 24, when availableFlagLXCol is 1 (S2 in FIG. 24).
104 YES), mvLXCol is scaled as necessary (S2105 in FIG. 24).
A procedure for scaling operation of the motion vector mvLXCol will be described with reference to FIGS.

FIG. 29 is a flowchart showing the motion vector scaling calculation processing procedure in step S2105 of FIG.

The inter-picture distance td is calculated by subtracting the POC of the reference picture referenced in the list ListCol of the prediction block colPU from the POC of the picture colPic at a different time (S2601). Note that when the POC of the reference picture referenced in the list Col of the prediction block colPU is earlier in the display order than the picture colPic at a different time, the inter-picture distance td is a positive value, and the prediction is more accurate than the picture colPic at a different time. When the POC of the reference picture referenced in the list ListCol of the block colPU is later in the display order, the inter-picture distance td becomes a negative value.
td = POC of picture colPic at different time-POC of reference picture referenced by list ListCol of prediction block colPU

The inter-picture distance tb is calculated by subtracting the POC of the reference picture referenced by the current encoding or decoding target picture list LX from the POC of the current encoding or decoding target picture (S2602). If the reference picture referenced in the list LX of the current encoding or decoding target picture is earlier than the current encoding or decoding target picture in the display order, the inter-picture distance tb is a positive value. When the reference picture referred to in the encoding or decoding target picture list LX is later in the display order, the inter-picture distance tb is a negative value.
tb = POC of the current encoding or decoding target picture-POC of the reference picture referenced in the reference list LX of the current encoding or decoding target picture

Subsequently, the inter-picture distances td and tb are compared (S2603), and the inter-picture distances td and tb are compared.
If b is equal (YES in S2603), the scaling calculation process ends. When the inter-picture distances td and tb are not equal (NO in S2603), scaling operation processing is performed by multiplying mvLXCol by the scaling coefficient tb / td according to the following equation (S2604) to obtain a scaled motion vector mvLXCol.
mvLXCol = tb / td * mvLXCol

Further, an example in which the scaling operation in step S2604 is performed with integer precision operation is shown in FIG.
0. The processing of steps S2605 to S2607 in FIG. 30 is the same as step S26 in FIG.
This corresponds to the process 04.

First, as in the flowchart of FIG. 29, the inter-picture distance td and the inter-picture distance tb are calculated (S2601, S2602).

Subsequently, the inter-picture distances td and tb are compared (S2603), and the inter-picture distances td and tb are compared.
If b is equal (YES in S2603), the scaling calculation process ends. If the inter-picture distances td and tb are not equal (NO in S2603), a variable tx is calculated by the following equation (S2605).
tx = (16384 + Abs (td / 2)) / td

Subsequently, the scaling coefficient DistScaleFactor is calculated by the following equation (S2606).
DistScaleFactor = (tb * tx + 32) >> 6

Subsequently, a scaled motion vector mvLXN is obtained by the following equation (S2607).
mvLXN = ClipMv (Sign (DistScaleFactor * mvLXN) * ((Abs (DistScaleFactor * mv
LXN) + 127) >> 8))

The procedure for adding the predicted motion vector candidate in S304 of FIG. 18 to the predicted motion vector list will be described in detail.

The prediction motion vector candidates mvLXA, mvLXB, and mvLXCol of the LX calculated in S301, S302, and S303 of FIG. 18 are added to the LX prediction motion vector list mvpListLX (S304). In the embodiment of the present invention, priorities are assigned and prediction motion vector candidates mvLXA, mvLXB, mvL are assigned to the LX prediction motion vector list mvpListLX from the highest priority order.
By registering XCol, elements with higher priority are placed in front of the motion vector predictor list. When limiting the number of elements in the motion vector predictor list in S306 of FIG. 18, the elements arranged at the rear of the motion vector predictor list are removed from the motion vector predictor list to leave the elements with higher priority.

The motion vector predictor list mvpListLX has a list structure, is managed by an index i indicating the location inside the motion vector predictor list, and has a storage area for storing a motion vector predictor candidate corresponding to the index i as an element. The number of the index i starts from 0, and motion vector predictor candidates are stored in the storage area of the motion vector predictor list mvpListLX. In the subsequent processing, the index i registered in the predicted motion vector list mvpListLX
Candidate motion vector predictors that are elements of are represented by mvpListLX [i].

Next, the registration processing method of LX predicted motion vector candidates mvLXA, mvLXB, and mvLXCol to the LX predicted motion vector list mvpListLX in S304 of FIG. 18 will be described in detail. FIG.
1 is a flowchart showing the predicted motion vector candidate registration processing procedure in step S304 of FIG.

First, the index i of the motion vector predictor list mvpListLX is set to 0 (S3101).
). When availableFlagLXA is 1 (YES in S3102), the motion vector predictor list mvpL
The LX predicted motion vector candidate mvLXA is registered at the position corresponding to the index i of istLX (S
3103) and is updated by adding 1 to the index i (S3104).

Subsequently, when availableFlagLXB is 1 (YES in S3105), an LX predicted motion vector candidate mvL is located at the position corresponding to the index i of the predicted motion vector list mvpListLXmvpListLX.
XB is registered (S3106) and updated by adding 1 to index i (S3107).
.

Subsequently, when availableFlagLXCol is 1 (YES in S3108), the LX predicted motion vector candidate mvLXCol is registered at the position corresponding to the index i of the predicted motion vector list mvpListLX (S3109), and the registration process to the predicted motion vector list is performed. finish.

In the above processing, the respective motion vector candidates for LX are represented by mvLXA, mvLXB, mv
Added to the LX prediction motion vector list mvpListLX in the order of LXCol, but the prediction mode is less than the specified size and the number of candidates is 1, and the partition mode (PartMode) is 2N × N partition (PA
RT_2NxN), when the partition index PartIdx is 0, or when the partition mode (PartMode) is N × 2N partition (PART_Nx2N) and the partition index PartIdx is 1, mxLXB, mvLXA , mvLXCol in the order of motion vector list m
By adding to vpListLX, a predicted motion vector mvLXB that is likely to have a value close to the motion vector of the prediction block to be encoded or decoded is registered at the beginning of the motion vector list so that it can be easily selected. The code amount of the difference motion vector can be reduced. As described above, the motion vector predictor candidate number limiting unit 124 sets the priority order of motion vector predictor candidates remaining in the motion vector predictor candidate list in accordance with the division mode in which the block to be encoded or decoded is divided into prediction blocks. To do.

When the partition mode (PartMode) is 2N × N partition (PART_2NxN) shown in FIG.
Since the motion vector of the upper prediction block whose partition index PartIdx is 0 is likely to have a motion vector value close to the prediction motion vector from the upper prediction block group in contact with the long side, the upper prediction block group Candidate mvLXB is registered in front of the motion vector predictor list so that it can be selected with priority, and the partition index PartIdx is 1.
Since the motion vector of the lower prediction block is likely to have a different motion vector value from the upper prediction block, the motion vector candidates from the left prediction block group
In order to facilitate selection of mvLXA, it is registered in front of the motion vector predictor list.

As shown in FIG. 4C, when the partition mode (PartMode) is N × 2N partition (PART_Nx2N),
Since the motion vector of the left prediction block whose partition index PartIdx is 0 is likely to have a motion vector value close to the prediction motion vector from the left prediction block group in contact with the long side, the left prediction block group The candidate mvLXA is registered in front of the prediction motion vector list so that it can be preferentially selected, and the motion vector of the right prediction block whose partition index PartIdx is 1 has a different motion vector value from that of the left prediction block. Therefore, the motion vector candidate mvLXB from the upper prediction block group is registered in front of the motion vector predictor list so that it can be preferentially selected.

FIG. 34 shows the size of the prediction block, the partition mode (PartMode), and the partition index PartId.
Candidate motion vector predictors for LX to the motion vector list mvpListLX for LX according to x
It is a flowchart which shows the registration processing procedure which switches the order of mvLXA, mvLXB, mvLXCol adaptively.

First, when the predicted block is smaller than the specified size (YES in S3201), the partition mode (Part
Mode is 2N × N partition (PART_2NxN) and the partition index PartIdx is 0, or the partition mode (PartMode) is N × 2N partition (PART_Nx2N) and the partition index PartIdx is 1 (YES in S3202). The candidate motion vector mv of LX in 35 processing steps
Register in the predicted motion vector list mvpListLX of LX in the order of LXB, mvLXA, mvLXCol (S3
203). If the above conditions are not met (NO in S3201 and NO in S3202), the LX predicted motion vector candidates mvLXA, mvLXB, and mvLXCol are registered in the LX predicted motion vector list mvpListLX in the above-described processing procedure of FIG. (S3204).

FIG. 35 shows the size of the prediction block, the partition mode (PartMode), and the partition index PartId.
Candidate motion vector predictors for LX to the motion vector list mvpListLX for LX according to x
It is a flowchart which shows the registration processing procedure in order of mvLXB, mvLXA, and mvLXCol.

First, the index i of the motion vector predictor list mvpListLX is set to 0 (S3301).
). When availableFlagLXB is 1 (YES in S3302), the motion vector predictor list mvpL
mvLXB is registered at the position corresponding to index i of istLX (S3303), and index i is registered.
It is updated by adding 1 (S3304).

Subsequently, when availableFlagLXA is 1 (YES in S3305), mvLXA is registered at a position corresponding to the index i of the predicted motion vector list mvpListLXmvpListLX (S3306).
The index i is updated by adding 1 (S3307).

Subsequently, when availableFlagLXCol is 1 (YES in S3308), mvLXCol is registered at a position corresponding to the index i of the motion vector predictor list mvpListLX (S3309), and the registration process to the motion vector predictor list is terminated.

Next, a method for deleting redundant prediction motion vector candidates in the prediction motion vector list in S305 of FIG. 18 will be described in detail. FIG. 32 is a flowchart showing the predicted motion vector redundant candidate deletion processing procedure in S305 of FIG.

When the final candidate number finalNumMVPCand is larger than 1 (YES in S4101), the motion vector redundancy candidate deletion units 123 and 223 compare motion vector candidates registered in the motion vector predictor list mvpListLX (S4102), If the motion vector candidates have the same value or close values (YES in S4103), the motion vector candidates are determined to be redundant motion vector candidates, and are redundant except for the motion vector candidate with the smallest order, that is, the smallest index i. A candidate for a motion vector is removed (S4104). After the redundant motion vector candidates are removed, the predicted motion vector list mvpListLX has an empty storage area for the deleted predicted motion vector candidates. Are packed in the order of the predicted motion vector candidates with the smallest (S4105). For example, if the motion vector candidate mvListLX [0] with index i 0 is deleted and the motion vector candidates mvListLX [1] and mvListLX [2] with index i 1 and 2 remain, the index i is 1 The predicted motion vector candidate mvListLX [1] is newly changed to a predicted motion vector candidate mvListLX [0] having an index i of 0. Furthermore, a predicted motion vector candidate mv whose index i is 2
ListLX [2] is newly changed to a predicted motion vector candidate mvListLX [1] with index i = 1. Further, it is set that the motion vector candidate mvListLX [2] having the index i of 2 does not exist.

When the final candidate number finalNumMVPCand is 1 (NO in S4101), it is not necessary to perform the process of deleting redundant motion vector predictor candidates in S305, and thus the redundant candidate deletion process is terminated. This is because the number of candidates is limited to one in the process of limiting the number of elements in step S306.

When the size of the prediction block is small, the number of prediction blocks per unit area increases, so that the number of processes for deleting redundant prediction motion vector candidates also increases.

Therefore, in this embodiment, when the prediction block to be encoded or decoded is equal to or smaller than the specified size, the final candidate number finalNumMVPCand is set to 1 to skip the process of deleting redundant motion vector predictor candidates. , Reducing the amount of processing.

If the final candidate number finalNumMVPCand is 2, and all of the motion vector candidates mvpLXA, mvpLXB, and mvpLXCol are registered in the motion vector predictor list mvpListLX and the number of candidates is 3, the element of the motion vector predictor list mvpListLX with the motion vector predictor index 0 MvpListLX [0]
Becomes mvpLXA, and mvpListLX [1], whose element is the motion vector predictor index 1, is mvpLXB
Thus, mvpListLX [2], which is an element having a predicted motion vector index of 2, becomes mvpLXCol. In this case, to make a brute force comparison, in step S4102, the motion vector predictor list mvpL
mvpListLX [0], which is an element having a predicted motion vector index of istLX, is compared with mvpListLX [1], which is an element having a predicted motion vector index of 1, and an element having a predicted motion vector index of 0 of the predicted motion vector list mvpListLX. MvpListLX [0] and mvpListLX [2] whose predicted motion vector index is 2 need to be compared, and two comparison processes are required. However, to reduce the amount of processing, the final candidate number finalNumMVPCand is 2
In this case, in step S4102, mvpListLX [0] whose predicted motion vector index is 0 in the predicted motion vector list mvpListLX is compared only with mvpListLX [1] whose predicted motion vector index is 1, and a redundant motion vector is compared. MvpListLX [1], which is an element having a predicted motion vector index of 1 when it is determined to be a candidate, and when an element mvpListLX [2] having a predicted motion vector index of 2 exists, the predicted motion vector index is set to 1.
Can be set to element mvpListLX [1] with a predicted motion vector index of 1, and this process can be terminated. In this case, mv whose new motion vector predictor index is 0
If pListLX [0] is compared with the element mvpListLX [1] whose predicted motion vector index is 1, there is a possibility that it is redundant. However, if these two elements are compared and determined to be redundant, one is deleted. Even if the number of candidates is 1, a motion vector having a value of (0, 0) is registered as an element mvpListLX [1] with a predicted motion vector index of 1 in step S306 described later, and the number of candidates is 2.
It becomes. It is considered that the advantage of deleting one of them and registering a motion vector having a value of (0, 0) is small. Only the mvpListLX [1] element can be compared to reduce the processing amount. In addition, spatial prediction motion vector candidates mvpLXA and mvpLXB derive prediction motion vector candidates from prediction blocks of the same picture, so there is a high possibility that the motion information is the same, but temporal prediction motion vector candidates mvpLXCol are predictions of different pictures. Since the motion vector predictor candidate is derived from the block, there is a high possibility that the motion information is different from the spatial motion vector predictor candidates mvpLXA and mvpLXB. Therefore, even if the comparison of temporal prediction motion vector candidates mvpLXCol is omitted, it is considered that the influence is small. As described above, when the number of final candidates is 2, the predicted motion vector candidate with the predicted motion vector index of 0 is compared with the predicted motion vector candidate with the predicted motion vector index of 1, and the predicted motion vector index of 2 is predicted. By omitting the comparison with the vector candidate, it is possible to reduce the number of condition determination processes for deleting the redundant candidate.

Next, the method for limiting the number of motion vector candidates in the predicted motion vector list in S306 of FIG. 18 will be described in detail. FIG. 33 is a flowchart for explaining the predicted motion vector candidate number limit processing procedure in S306 of FIG.

The predicted motion vector candidate number limit unit 124 and the predicted motion vector candidate number limit unit 224
Number of motion vector motion vector candidates num registered in the motion vector motion vector list mvpListLX
Limit MVPCandLX to the specified final candidate number finalNumMVPCand.

First, the number of elements registered in the LX prediction motion vector list mvpListLX is counted and set to the number of LX prediction motion vector candidates numMVPCandLX (S5101).

Subsequently, when the number of predicted motion vectors numMVPCandLX of LX is smaller than the number of final candidates finalNumMVPCand (YES in S5103), the index i of the predicted motion vector list mvpListLX of LX has a value of (0, 0) at the position corresponding to numMVPCandLX. Register a motion vector with (
S5104), 1 is added to numMVPCandLX (S5105). numMVPCandLX and finalNumMVP
If Cand has the same value (YES in S5106), this restriction process is terminated, and numMVPCandLX and fina
If lNumMVPCand is not the same value (NO in S5106), step S
The processes of 5104 and S5105 are repeated. That is, the number of motion vector predictor candidates for LX numM
MVs having a value of (0, 0) are registered until VPCandLX reaches the final candidate number finalNumMVPCand.
In this way, by registering MVs having a value of (0, 0) overlappingly, the predicted motion vector is determined regardless of the value of the predicted motion vector index within the range of 0 or more and less than the final candidate number finalNumMVPCand. be able to.

On the other hand, when the number of predicted motion vectors numMVPCandLX for LX is larger than the number of final candidates finalNumMVPCand (NO in S5103, YES in S5107), all predicted motion vectors for which the index i of the predicted motion vector list mvpListLX for LX is greater than finalNumMVPCand-1 The candidate is deleted (S5108), and the same value as finalNumMVPCand is set in numMVPCandLX (S
5109), this restriction process is terminated.

When the number of predicted motion vectors numMVPCandLX of LX is equal to the number of final candidates finalNumMVPCand (NO in S5103, NO in S5107), the limiting process is terminated without performing the limiting process.

In the present embodiment, the final candidate number finalNumMVPCand according to the size of the prediction block
Is stipulated. This is because if the number of motion vector predictor candidates registered in the motion vector predictor list fluctuates according to the state of construction of the motion vector predictor list, the motion vector list on the decoding side must be constructed before the motion vector predictor list is constructed. This is because entropy decoding cannot be performed. Furthermore, if entropy decoding depends on the construction state of the motion vector predictor list including the motion vector candidate mvLXCol derived from the prediction block of the picture at different time, when an error occurs when decoding the encoded bit string of another picture The encoded bit string of the current picture is also affected by this, and there is a problem that entropy decoding cannot be continued normally. Final candidate number finalNumMVPCand depending on the size of the prediction block
If a fixed number is specified, the prediction motion vector index can be entropy-decoded independently of the construction of the prediction motion vector list, and even if an error occurs when decoding the encoded bit string of another picture, The entropy decoding of the coded bit string of the current picture can be continued without receiving the message.

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

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

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

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

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

DESCRIPTION OF SYMBOLS 101 Image memory, 102 Motion vector detection part, 103 Difference motion vector calculation part, 104 Inter prediction information estimation part, 105 Motion compensation prediction part, 106 Prediction method determination part, 107 Residual signal generation part, 108 Orthogonal transformation and quantization part 109 first encoded bit string generation unit, 110 second encoded bit string generation unit, 111 multiplexing unit, 112 inverse quantization / inverse orthogonal transform unit, 113 decoded image signal superimposing unit, 114 encoded information storage memory, 115 decoded image memory, 121 prediction motion vector candidate generation unit, 122 prediction motion vector candidate registration unit, 123 prediction motion vector redundant candidate deletion unit, 124 prediction motion vector candidate number limit unit, 125 prediction motion vector candidate code amount calculation unit, 126 Prediction motion vector selection unit, 127 Motion vector subtraction unit, 201
Separation unit, 202 first encoded bit sequence decoding unit, 203 second encoded bit sequence decoding unit, 204 motion vector calculation unit, 205 inter prediction information estimation unit, 206 motion compensation prediction unit, 207 inverse quantization / inverse orthogonal transform unit, 208 decoded image signal superimposing unit, 2
09 encoding information storage memory, 210 decoded image memory, 221 prediction motion vector candidate generation unit, 222 prediction motion vector candidate registration unit, 223 prediction motion vector redundant candidate deletion unit, 224 prediction motion vector candidate number limiting unit, 225 prediction motion vector A selection unit, 226 a motion vector addition unit.

Claims (1)

A moving picture decoding apparatus for decoding a coded bit string in which a moving picture is coded using a motion vector in units of blocks obtained by dividing each picture,
A decoding unit that decodes information indicating an index of a motion vector predictor to be selected in the motion vector predictor candidate list;
A first and second predicted motion vector candidate is derived from any motion vector of a decoded block adjacent to the decoding target block in the same picture as the decoding target block, and a decoded picture different from the decoding target block A motion vector predictor candidate generation unit for deriving a third motion vector predictor candidate from any one of the motion vectors in the block;
A predicted motion vector candidate registration unit that registers the first, second, and third predicted motion vector candidates satisfying a predetermined condition in a predicted motion vector candidate list;
When the value of the first motion vector predictor candidate registered in the motion vector predictor candidate list by the motion vector candidate registration unit is the same as the value of the second motion vector predictor candidate, the motion vector predictor candidate list A motion vector predictor redundancy determining unit that deletes the second motion vector predictor candidate from
When the number of motion vector predictor candidates registered in the motion vector predictor candidate list is smaller than a predetermined number (two or more natural numbers), the prediction motion vector candidates are repeated until the number of motion vector predictor candidates reaches a predetermined number. A motion vector predictor candidate restriction unit that registers motion vector predictor candidates having a list index value of (0, 0) at a position corresponding to the number of motion vector predictor candidates;
A prediction motion vector selection unit that selects a prediction motion vector of the decoding target block from the prediction motion vector candidate list based on the decoded information indicating the index of the prediction motion vector to be selected;
The moving image characterized in that the predicted motion vector candidate redundancy determining unit does not compare the value of the first predicted motion vector candidate and the value of the second predicted motion vector candidate with the value of the third predicted motion vector candidate. Image decoding device.

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