JP7679899B2 - Video encoding device, video encoding method, and video encoding program - Google Patents

Description

The present invention relates to image encoding and decoding technology that divides an image into blocks and performs prediction.

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

In the coding and decoding of moving images, coding efficiency is improved by inter-prediction, which predicts from pictures that have already been coded and decoded. Patent Document 1 describes a technique for applying affine transformation during inter-prediction. In moving images, it is not uncommon for objects to undergo transformations such as enlargement, reduction, and rotation, and by applying the technique of Patent Document 1, efficient coding becomes possible.

Japanese Patent Application Publication No. 9-172644

However, the technique of Patent Document 1 involves image conversion, and therefore has a problem of a large processing load. In view of the above problem, the present invention provides an efficient encoding technique with a low load.

In one aspect of the present invention that solves the above problem, the present invention includes a merge candidate list construction unit that constructs a merge candidate list including spatial merge candidates, a normal merge candidate selection unit that selects a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list, and a triangular merge candidate selection unit that selects a first triangular merge candidate that is uni-predictive and a second triangular merge candidate that is uni-predictive from the merge candidate list, and the triangular merge mode selection unit sets the priority of motion information to the same for the first triangular merge candidate and the second triangular merge candidate.

The present invention makes it possible to achieve highly efficient image encoding and decoding processing with low load.

1 is a block diagram of an image encoding device according to an embodiment of the present invention. 1 is a block diagram of an image decoding device according to an embodiment of the present invention. 13 is a flowchart for explaining an operation of dividing a tree block. FIG. 13 is a diagram showing how an input image is divided into tree blocks. FIG. 1 is a diagram illustrating z-scanning. FIG. 13 is a diagram showing the divided shapes of blocks. 13 is a flowchart for explaining an operation of dividing a block into four. 11 is a flowchart for explaining an operation of dividing a block into two or three. This is a syntax for expressing the shape of block division. FIG. 1 is a diagram illustrating intra prediction. FIG. 13 is a diagram for explaining reference blocks for inter prediction. This is a syntax for expressing a coding block prediction mode. FIG. 11 is a diagram showing the correspondence between syntax elements and modes relating to inter prediction. FIG. 13 is a diagram for explaining affine transformation motion compensation of two control points. FIG. 13 is a diagram for explaining affine transformation motion compensation of three control points. 2 is a block diagram showing a detailed configuration of the inter prediction unit 102 in FIG. 1. 17 is a block diagram showing a detailed configuration of a normal predicted motion vector mode derivation unit 301 in FIG. 16. 17 is a block diagram showing a detailed configuration of a normal merge mode derivation unit 302 in FIG. 16. 17 is a flowchart for explaining a normal prediction motion vector mode derivation process of the normal prediction motion vector mode derivation unit 301 of FIG. 16 . 13 is a flowchart showing a processing procedure of a normal predicted motion vector mode derivation process. 13 is a flowchart illustrating a procedure for a normal merge mode derivation process. 3 is a block diagram showing a detailed configuration of an inter prediction unit 203 in FIG. 2. 23 is a block diagram showing a detailed configuration of a normal predicted motion vector mode derivation unit 401 in FIG. 22. 23 is a block diagram showing a detailed configuration of a normal merge mode derivation unit 402 in FIG. 22. 23 is a flowchart for explaining a normal prediction motion vector mode derivation process of the normal prediction motion vector mode derivation unit 401 of FIG. 22. 17 is a block diagram showing a detailed configuration of a sub-block predicted motion vector mode derivation unit 303 in FIG. 16. 23 is a block diagram showing a detailed configuration of a sub-block predicted motion vector mode derivation unit 403 in FIG. 22. 17 is a block diagram showing a detailed configuration of a sub-block merge mode derivation unit 304 in FIG. 16. 23 is a block diagram showing a detailed configuration of a sub-block merge mode derivation unit 404 in FIG. 22. FIG. 13 is a diagram for explaining derivation of affine inheritance predicted motion vector candidates. FIG. 13 is a diagram for explaining derivation of affine construction predicted motion vector candidates. FIG. 13 is a diagram for explaining affine inheritance merge candidate derivation. FIG. 13 is a diagram illustrating affine construction merge candidate derivation. 13 is a flowchart of deriving an affine inheritance predicted motion vector candidate. 13 is a flowchart of deriving an affine constructed predicted motion vector candidate. 13 is a flowchart of affine inheritance merge candidate derivation. 13 is a flowchart of affine construct merge candidate derivation. 13 is a flowchart illustrating a procedure of a history motion vector predictor candidate list initialization/update process. 13 is a flowchart of a procedure of a same element confirmation process in the procedure of a process of deriving a history predicted motion vector candidate. 13 is a flowchart of an element shifting process procedure in the history motion vector predictor candidate derivation process procedure. 13 is a flowchart illustrating a procedure of a process of deriving a history predicted motion vector candidate. 13 is a flowchart illustrating a history merging candidate derivation process procedure. 11 is a diagram illustrating an example of a history motion vector predictor candidate list update process. FIG. 13 is a flowchart for explaining an operation of a sub-block temporal merging candidate derivation unit 381. 13 is a flowchart illustrating a process of deriving adjacent motion information of a block. 13 is a flowchart illustrating a process of deriving a temporal motion vector. 13 is a flowchart illustrating derivation of inter prediction information. 13 is a flowchart illustrating a process of deriving sub-block motion information. FIG. 2 is a diagram for explaining the temporal relationship between pictures. 13 is a flowchart for explaining a process of deriving a temporal motion vector predictor candidate in a normal motion vector predictor mode derivation unit 301. 13 is a flowchart for explaining the derivation process of ColPic in the derivation process of a temporal motion vector predictor candidate in the normal motion vector predictor mode derivation unit 301. 13 is a flowchart for explaining a process of deriving coding information of ColPic in a process of derivation of a temporal motion vector predictor candidate in the normal motion vector predictor mode derivation unit 301. 13 is a flowchart illustrating a process of deriving inter prediction information. 13 is a flowchart showing the procedure of a process for deriving inter prediction information of a coding block when the inter prediction mode of the coding block colCb is bi-prediction (Pred_BI). 13 is a flowchart illustrating a procedure of a motion vector scaling calculation process. 13 is a flowchart illustrating a process of deriving a temporal merge candidate. FIG. 13 is a diagram for explaining motion compensation prediction in the case of L0 prediction in which the L0 reference picture (RefL0Pic) is at a time earlier than the current picture (CurPic) to be processed. FIG. 13 is a diagram for explaining motion compensation prediction in the case where L0 prediction is performed and a reference picture for L0 prediction is located at a later time than the current picture to be processed. FIG. 13 is a diagram for explaining motion compensation prediction in a bi-predictive case where a reference picture for L0 prediction is at a time earlier than a current picture to be processed and a reference picture for L1 prediction is at a time later than a current picture to be processed. FIG. 13 is a diagram for explaining the prediction direction of motion compensation prediction in bi-prediction where the reference picture for L0 prediction and the reference picture for L1 prediction are located at a time earlier than the current picture. FIG. 13 is a diagram for explaining the prediction direction of motion compensation prediction in bi-prediction where the reference picture for L0 prediction and the reference picture for L1 prediction are at a time later than the current picture. 13 is a flowchart illustrating an average merging candidate derivation process; 11 is a table showing information regarding merge motion vector difference. FIG. 13 is a diagram illustrating the derivation of a merge differential motion vector. FIG. 13 is a diagram illustrating a prediction of a triangle merge mode. 13 is a flowchart illustrating derivation of triangle merge candidates. 13 is a flowchart illustrating derivation of uni-prediction motion information for merged triangular partitions. FIG. 1 is a diagram illustrating a merging triangular index and a merging triangular partition.

Definitions of the technologies and technical terms used in this embodiment.

<Tree Block>
In this embodiment, an image to be encoded/decoded is divided equally into a predetermined size. This unit is defined as a tree block. As shown in FIG. 4, in this embodiment, the size of the tree block is set to 128x128 pixels, but the size of the tree block is not limited to this and may be set to any size. The tree block to be processed (corresponding to the encoding target in the encoding process and the decoding target in the decoding process) is arranged in a raster scan order,
That is, the order is from left to right and from top to bottom. The inside of each tree block can be further divided recursively. The block to be encoded and decoded after tree block division is defined as an encoding block. Furthermore, tree blocks and encoding blocks are collectively defined as blocks. Efficient encoding is possible by performing appropriate block division. The size of the tree block can be a fixed value previously agreed upon between the encoding device and the decoding device, or it can be configured so that the size of the tree block determined by the encoding device is transmitted to the decoding device.

<Prediction mode>
Intra prediction (MO) is a method for predicting the surrounding image signals of the processed image (in the encoding process, the signal for which encoding has been completed is used for the decoded image, image signal, tree block, block, coding block, etc., and in the decoding process, the signal for which decoding has been completed is used for the image, image signal, tree block, block, coding block, etc.) for each coding block to be processed.
The prediction mode (PredMode) is defined as a mode for distinguishing between intra prediction (MODE_INTRA) and inter prediction (MODE_INTER).
It has the values MODE_INTRA, or inter prediction (MODE_INTER).

<Inter prediction>
In inter prediction, which performs prediction from the image signal of a processed image, multiple processed images can be used as reference pictures. To manage multiple reference pictures, two types of reference lists, L0 (reference list 0) and L1 (reference list 1), are defined, and reference pictures are identified using reference indices for each. L0 prediction (Pred_L0) is available for P slices. L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI) are available for B slices.
) is available. L0 prediction (Pred_L0) is inter-prediction that refers to a reference picture managed by L0, and L1 prediction (Pred_L1) is inter-prediction that refers to a reference picture managed by L1. Bi-prediction (Pred_BI) is where both L0 prediction and L1 prediction are performed,
This is inter-prediction that refers to one reference picture managed in each of L0 and L1. Information that specifies L0 prediction, L1 prediction, or bi-prediction is defined as an inter-prediction mode. In the following processing, constants and variables with the subscript LX in the output are L0, L1
It is assumed that processing is performed for each

<Predictive motion vector mode>
The predicted motion vector mode is a mode in which an index for identifying a predicted motion vector, a differential motion vector, an inter prediction mode, and a reference index are transmitted to determine inter prediction information for a block to be processed. The predicted motion vector is derived from a predicted motion vector candidate derived from a processed block adjacent to the block to be processed, or a block belonging to a processed image that is located at the same position as the block to be processed or in the vicinity (neighborhood), and an index for identifying the predicted motion vector.

<Merge mode>
The merge mode is a mode in which inter-prediction information for the block to be processed is derived from inter-prediction information for a processed block adjacent to the block to be processed, or a block belonging to a processed image that is located at the same position as the block to be processed or in its vicinity (vicinity), without transmitting a differential motion vector or a reference index.

The spatial merge candidates are defined as processed blocks adjacent to the current block and the inter prediction information of the processed blocks. The temporal merge candidates are defined as blocks belonging to the processed image that are located at the same position as the current block or in the vicinity of the current block and the inter prediction information derived from the inter prediction information of the processed blocks. Each merge candidate is registered in a merge candidate list, and a merge index identifies the merge candidate to be used in predicting the current block.

<Adjacent blocks>
FIG. 11 is a diagram illustrating reference blocks to be referenced for deriving inter prediction information in the predicted motion vector mode and the merge mode.
B3 is a processed block adjacent to the current block T0 is a block belonging to the processed image, which is located at the same position as the current coding block of the current image or in the vicinity thereof.

A1 and A2 are blocks located to the left of the coding block to be processed and adjacent to the coding block to be processed. B1 and B3 are blocks located above the coding block to be processed and adjacent to the coding block to be processed. A0, B0, and B2 are blocks located at the bottom left, top right, and top left, respectively, of the coding block to be processed.

How adjacent blocks are handled in the predicted motion vector mode and merge mode will be described in detail later.

<Affine transformation motion compensation>
Affine transformation motion compensation is a method of dividing an encoding block into subblocks of a predetermined unit, and setting a motion vector for each subblock individually to perform motion compensation. The motion vector of each subblock is derived based on one or more control points derived from inter prediction information of a processed block adjacent to the processing target block, or a block belonging to a processed image that is located at the same position as the processing target block or in the vicinity (neighborhood). In this embodiment, the size of the subblock is 4x4 pixels, but the size of the subblock is not limited to this, and the motion vector may be derived in units of pixels.

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

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

<Syntax of coding block>
The syntax for expressing the prediction mode of a coding block will be described with reference to Fig. 12(a), Fig. 12(b), and Fig. 13. In Fig. 12(a), pred_mode_flag is a flag indicating whether or not the prediction mode is inter prediction. If pred_mode_flag is 0, the prediction mode is inter prediction, and if pred_mode_flag is 1, the prediction mode is inter prediction.
If de_flag is 1, it is intra prediction. In the case of intra prediction, the intra prediction information i
In the case of inter prediction, the flag inter_pred_mode is sent, and in the case of inter prediction, the flag merge_flag is sent. The flag merge_flag indicates whether to use the merge mode or the predicted motion vector mode. In the case of the predicted motion vector mode (merge_flag=0), the flag inter_affine_flag is sent, indicating whether to apply the sub-block predicted motion vector mode. In the case of applying the sub-block predicted motion vector mode (inter_affine_flag=1), the flag cu_affine_type_flag is sent.
g is a flag for determining the number of control points in the sub-block predicted motion vector mode.

On the other hand, in the case of the merge mode (merge_flag=1), the merge_subblock_flag in FIG. 12B is sent. The merge_subblock_flag is a flag indicating whether or not the subblock merge mode is applied. In the case of the subblock merge mode (merge_subblock_flag=1), the merge index merge_subblock_idx is sent. On the other hand, in the case of the non-subblock merge mode (merge_
subblock_flag=0), flag merge_triangle_fl indicating whether to apply triangle merge mode
ag. If triangle merge mode is applied (merge_triangle_flag=1), the block split direction merge_triangle_split_dir and merge triangle indexes merge_triangle_idx0, merge_triangle_idx1 are sent for each of the two partitions. On the other hand, if triangle merge mode is not applied (merge_triangle_flag=0), merge indexes merge_idx
Send.

FIG. 13 shows the values of each syntax element and the corresponding prediction modes.
flag=0, inter_affine_flag=0 corresponds to a normal predicted motion vector mode (Inter Pred Mode). merge_flag=0, inter_affine_flag=1 corresponds to a sub-block predicted motion vector mode (
Inter Affine Mode). merge_flag=1,merge_subblock_flag=0,merge_trianlge
_flag=0 corresponds to the normal merge mode. merge_flag=1,merge_subblock
_flag=0,merge_trianlge_flag=1 corresponds to the triangle merge mode. merge_flag=1,merge_subblock_flag=1 corresponds to the subblock merge mode.
Supports the following modes:

<POC>
POC (Picture Order Count) is a variable associated with the picture to be coded,
A value is set that increases by one in the output order of a picture. The POC value can be used to determine whether the pictures are the same, to determine the order of pictures in the output order, and to derive the distance between pictures. For example, if two pictures have the same POC value, they can be determined to be the same picture. If two pictures have different POC values, the picture with the smaller POC value can be determined to be the picture that will be output first, and so on.
The difference in POC between two pictures indicates the distance between the pictures in the time axis direction.

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

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

The block division unit 101 recursively divides an input image to generate coding blocks. The block division unit 101 includes a 4-division unit that divides the block to be divided in the horizontal and vertical directions, respectively, and a 2-3 division unit that divides the block to be divided in either the horizontal or vertical direction. The block division unit 101 supplies the generated image signal of the coding block to be processed to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106. The block division unit 101 also supplies information indicating the determined recursive division structure to the bit string coding unit 108.
The detailed operation of 1 will be described later.

The inter prediction unit 102 performs inter prediction of the coding block to be processed. A plurality of candidates for inter prediction information are derived from the inter prediction information stored in the coding information storage memory and the decoded image signal stored in the decoded image memory 104, an appropriate inter prediction mode is selected from the plurality of candidates, and the selected inter prediction mode and a predicted image signal corresponding to the selected inter prediction mode are supplied to the prediction method determination unit 105. The detailed configuration and operation of the inter prediction unit 102 will be described later.

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

The decoded image memory 104 stores the decoded image generated by the decoded image signal superimposing unit 110 .
The decoded image stored in the decoded image memory is predicted by the inter prediction unit 102 and the intra prediction unit 103.
Supply to 03.

The prediction method determination unit 105 determines an optimal prediction mode (inter prediction or intra prediction) for each prediction by evaluating the coding information and the code amount of the residual signal, the amount of distortion between the predicted image signal and the image signal to be processed, etc. In the case of the inter prediction merge mode, the prediction method determination unit 105 supplies the bit string coding unit 108 with coding information of the merge index and information indicating whether or not it is a sub-block merge mode (sub-block merge flag), and in the case of the inter prediction predicted motion vector mode, the bit string coding unit 108 supplies the inter prediction mode, predicted motion vector index, L0, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16, L17, L18, L21, L22, L23, L24, L25, L26, L27, L28, L39, L40, L41, L42, L43, L44, L45, L46, L47, L48, L59, L69, L69, L70, L81, L19, L122, L142, L150, L161, L172, L183, L194, L195, L196, L197, L198, L210, L222, L230, L241, L251, L252, L263, L274, L285, L296, L397, L398, L41, L42, L43, L44, L45, L46, L47, L48, L59, L69, L171, L195, L296, L297, L298, L399, L40, L41, L42, L43, L
The coding unit 105 supplies coding information such as a reference index of 1, a differential motion vector, and information indicating whether or not the mode is a sub-block mode (sub-block predicted motion vector flag) to the bit string coding unit 108. The determined coding information is supplied to the coding information storage memory 111.

The residual signal generating unit 106 generates a residual signal by subtracting the predicted image signal from the image signal to be processed, and supplies the residual signal to the orthogonal transform and quantization unit 107 .

The orthogonal transform and quantization unit 107 performs orthogonal transform and quantization on the residual signal in accordance with the quantization parameter to generate an orthogonally transformed and quantized residual signal, and supplies it to the bit string coding unit 108 and the inverse quantization and inverse orthogonal transform unit 109 .

The bitstream coding unit 108 codes coding information according to the prediction method determined by the prediction method determination unit 105 for each coding block, in addition to information on a sequence, picture, slice, and coding block basis.
In the case of the division mode PartMode and inter prediction (PRED_INTER), the coding information such as a flag for determining whether or not the mode is a merge mode, a sub-block merge flag, a merge index in the case of the merge mode, an inter prediction mode in the case of the merge mode not being in the merge mode, a predicted motion vector index, information on the difference motion vector, and a sub-block predicted motion vector flag is coded according to a prescribed syntax rule described later to generate a first coded bit string. In addition, the bit string coding unit 108 entropy codes the orthogonally transformed and quantized residual signal according to a prescribed syntax rule to generate a second coded bit string. The first coded bit string and the second coded bit string are multiplexed according to a prescribed syntax rule to output a bit stream.

The inverse quantization and inverse orthogonal transform unit 109 inverse quantizes and inverse orthogonally transforms the orthogonally transformed and quantized residual signal supplied from the orthogonal transform and quantization unit 107 to calculate a residual signal, and supplies it to a decoded image signal superimposition unit 110.

The decoded image signal superimposition unit 110 superimposes the predicted image signal according to the determination by the prediction method determination unit 105 and the residual signal that has been inversely quantized and inversely orthogonally transformed by the inverse quantization and inverse orthogonal transformation unit 109 to generate a decoded image, and stores the decoded image in the decoded image memory 104. Note that the decoded image is subjected to a filtering process to reduce distortion such as block distortion caused by coding, and then stored in the decoded image memory 104.
may be stored in

The coding information storage memory 111 stores coding information such as the prediction mode (inter prediction or intra prediction) determined by the prediction method determination unit 105.
The coding information stored in the 3D prediction block includes a determined motion vector, a reference list, and
In addition to the reference index, in case of inter prediction merge mode, the merge index,
Encoding information of information indicating whether or not it is a sub-block merge mode (sub-block merge flag), in the case of a predicted motion vector mode of inter prediction, inter prediction mode, predicted motion vector index, L0, L1 reference index, differential motion vector, information indicating whether or not it is a sub-block mode (sub-block predicted motion vector flag), in the case of intra prediction,
The determined intra prediction mode, etc. The construction of the history candidate list managed by the coding information storage memory 111 will be described later.

Fig. 2 is a block diagram showing the configuration of a video decoding device according to an embodiment of the present invention, which corresponds to the video encoding device of Fig. 1. The video decoding device according to the embodiment includes a bit stream decoding unit 201, a block dividing unit 202, an inter prediction unit 203, an intra prediction unit 204, an encoded information storage memory 205, an inverse quantization and inverse orthogonal transform unit 206, a decoded image signal superimposition unit 207, and a decoded image memory 208.

2 corresponds to the decoding process provided inside the video encoding device of FIG. 1. Therefore, the configurations of the encoding information storage memory 205, the inverse quantization and inverse orthogonal transform unit 206, the decoded image signal superimposition unit 207, and the decoded image memory 208 in FIG. 2 are the same as those of the inverse quantization and inverse orthogonal transform unit 109, the decoded image signal superimposition unit 110, and the like in the video encoding device of FIG.
, the encoded information storage memory 111, and the decoded image memory 104, respectively.

The bit stream supplied to the bit stream decoding unit 201 is separated according to a prescribed syntax rule. The separated first coded bit stream is decoded to obtain information in units of sequences, pictures, slices, and coding blocks, and coding information in units of coding blocks. Specifically, inter prediction (PRED_INTER) or intra prediction (PRED_INTRA) is performed in units of coding blocks.
Prediction mode PredMode, partition mode PartMode, inter prediction (PRED_INTER)
In the case of the second bit stream, the coding information relating to a flag for determining whether or not the mode is a merge mode, a merge index in the case of the merge mode, a sub-block merge flag, and in the case of the predicted motion vector mode, an inter prediction mode, a predicted motion vector index, a differential motion vector, a sub-block predicted motion vector flag, and the like is decoded according to a prescribed syntax rule described later, and the coding information is supplied to the inter prediction unit 203 or the intra prediction unit 204, and the coding information storage memory 205. The separated second coded bit string is decoded to calculate an orthogonally transformed and quantized residual signal, and the orthogonally transformed and quantized residual signal is supplied to the inverse quantization and inverse orthogonal transform unit 206.

When the prediction mode PredMode of the coding block to be processed is the inter prediction (PRED_INTER) and the predicted motion vector mode, the inter prediction unit 203 stores the coding information in the coding information storage memory 205.
derives a plurality of candidate predictive motion vectors using the coding information of the already decoded image signal stored in the bit stream decoding unit 201, and registers the candidates in a candidate predictive motion vector list, which will be described later; and selects a predictive motion vector corresponding to the predictive motion vector index decoded and supplied by the bit stream decoding unit 201 from the plurality of candidate predictive motion vectors registered in the candidate predictive motion vector list;
A motion vector is calculated from the difference vector decoded by the bitstream decoding unit 201 and the selected predicted motion vector, and is stored in the coded information storage memory 205 together with other coded information. The coded information of the coded block supplied and stored here includes a prediction mode PredMode, a division mode Pa
rtMode, flags indicating whether to use L0 prediction and L1 prediction predFlagL0[xP][yP], pr
edFlagL1[xP][yP], L0 and L1 reference indices refIdxL0[xP][yP], refIdxL1[xP][yP]
, L0, L1 motion vectors mvL0[xP][yP], mvL1[xP][yP], etc., where xP and yP are indices indicating the position of the top left pixel of the coding block in the picture.
PredMode is inter prediction (MODE_INTER), and inter prediction mode is L0 prediction (Pred_L0)
In this case, the flag predFlagL0 indicating whether or not L0 prediction is used is 1, and the flag predFlagL1 indicating whether or not L1 prediction is used is 0. In the case where the inter prediction mode is L1 prediction (Pred_L1), the flag predFlagL0 indicating whether or not L0 prediction is used is 0, and the flag predFlagL1 indicating whether or not L1 prediction is used is 1. In the case where the inter prediction mode is bi-predictive (Pred_BI), both the flag predFlagL0 indicating whether or not L0 prediction is used and the flag predFlagL1 indicating whether or not L1 prediction is used are 1. Furthermore, when the prediction mode Pred of the coding block to be processed is
When the mode is inter prediction (PRED_INTER) and the merge mode is selected, a merge candidate is derived. A plurality of merge candidates are derived using the coding information of the already decoded coding block stored in the coding information storage memory 205, and are registered in a merge candidate list described later. A merge candidate corresponding to the merge index decoded and supplied by the bitstream decoding unit 201 is selected from the plurality of merge candidates registered in the merge candidate list, and flags predFlagL0[xP][yP] and predFlagL1[xP][yP] indicating whether or not to use the L0 prediction and L1 prediction of the selected merge candidate are used.
, L0 and L1 reference indexes refIdxL0[xP][yP], refIdxL1[xP][yP], L0 and L1 motion vectors mvL0[xP][yP], mvL1[xP][yP] are stored in the coding information storage memory 2.
05. Here, xP and yP are indexes indicating the position of the upper left pixel of the coding block in the picture. The detailed configuration and operation of the inter prediction unit will be described later.

The intra prediction unit 204 performs intra prediction when the prediction mode PredMode of the coding block to be processed is intra prediction (PRED_INTRA). The coding information decoded by the bitstream decoding unit 201 includes an intra prediction mode, and generates a predicted image signal by intra prediction from a decoded image signal stored in a decoded image memory 208 according to the intra prediction mode, and supplies the predicted image signal to a decoded image signal superimposition unit 207.
The intra prediction unit 4 corresponds to the intra prediction unit 103 of the image encoding device 100 and performs the same processing as the intra prediction unit 103.

The inverse quantization and inverse orthogonal transformation unit 206 performs inverse orthogonal transformation and inverse quantization on the orthogonally transformed and quantized residual signal decoded by the bit string decoding unit 201, thereby obtaining an inverse orthogonally transformed and inverse quantized residual signal.

The decoded image signal superimposition unit 207 superimposes the predicted image signal inter-predicted by the inter prediction unit 203 or the predicted image signal intra-predicted by the intra prediction unit 204 with a residual signal inversely orthogonally transformed and inversely quantized by the inverse quantization and inverse orthogonal transformation unit 206, thereby decoding the decoded image signal and storing it in the decoded image memory 208. When storing in the decoded image memory 208, the decoded image may be subjected to a filtering process for reducing block distortion and the like caused by encoding before being stored in the decoded image memory 208.

Next, the operation of the block division unit 101 in the image coding device 100 will be described.
3 is a flowchart showing an operation of dividing an image into tree blocks and further dividing each tree block. First, an input image is divided into tree blocks of a predetermined size (step S1001). Each tree block is scanned in a predetermined order, i.e., raster scan order (step S1002), and the inside of the tree block to be processed is divided (step S1003).

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

If it is determined that the processing block is to be divided into four, the processing block is divided into four (step S1102).
That is, scanning is performed in the order of upper left, upper right, lower left, and lower right (step S1103). Fig. 5 shows an example of the Z scan order, and 601 in Fig. 6 shows an example in which the processing target block is divided into four. Numbers 0 to 3 in 601 in Fig. 6 indicate the processing order. Then, for each block divided in step S1101, the flowchart in Fig. 7 is recursively called.

If it is determined that the processing target block is not to be divided into four, it is divided into two and three (step S1
105).

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

If it is not determined that the block to be processed should be divided into 2-3 parts, that is, if it is determined that no division should be made, the division is terminated (step S1211) and the process returns to the block in the upper hierarchy.

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

If it is determined that the processing target block is to be divided into two, it is determined whether or not to divide the processing target block vertically (step S1203), and based on the result of the determination, the processing target block is divided vertically (step S1204) or divided horizontally (step S1205).
Step S1205). As a result of step S1204, the processing target block is divided into two vertically as shown in FIG. 602. As a result of step S1205, the processing target block is divided into two vertically as shown in FIG.
As shown in FIG. 604, it is divided into two parts horizontally.

In step S1202, if it is not determined that the block to be processed is to be divided into two, that is, if it is determined that the block to be processed is to be divided into three, it is determined whether or not to divide the block to be processed vertically (step S1206), and based on the result, the block to be processed is divided vertically (step S1207) or the block to be processed is divided horizontally (step S1209).
1208). As a result of step S1207, the processing target block is divided vertically into three parts as shown in FIG. 603, and as a result of step S1208, the processing target block is divided horizontally into three parts as shown in FIG.

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

The recursive block division described here may limit the necessity of division depending on the number of divisions, the size of the block to be processed, etc. The information limiting the necessity of division may be realized in a configuration in which no information is transmitted by a prearrangement between the encoding device and the decoding device, or may be realized in a configuration in which the encoding device determines information limiting the necessity of division and transmits it to the decoding device by recording it in the encoded bit string.

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

Next, the operation of the block division unit 202 in the image decoding device 200 will be described. The block division unit 202 divides tree blocks in the same processing procedure as the block division unit 101 in the image encoding device 100. However, the block division unit 101 in the image encoding device 100 applies optimization techniques such as optimal shape estimation by image recognition and distortion rate optimization,
The difference is that, whereas the block dividing section 202 in the image decoding device 200 determines the block division shape by decoding block division information recorded in the encoded bit string.

Syntax for Block Division in the First Embodiment (Syntax Rules for Encoded Bit Strings)
The above is shown in Figure 9. coding_quadtree() represents the syntax for dividing a block into four parts, and multi_type_tree() represents the syntax for dividing a block into two or three parts. qt_split is a flag that indicates whether or not to divide a block into four parts. If the block is to be divided into four parts, qt_split=1 is used. If the block is not to be divided into four parts, qt_split=0 is used. If the block is to be divided into four parts (qt_split=
1) For each block, recursively divide it into four (coding_quadtree(0), c
coding_quadtree(1), coding_quadtree(2), coding_quadtree(3)).
mtt_split is a flag that indicates whether to split further. If further splitting is to be performed (mtt_split=1), the flag mtt_split_vertical, which indicates whether to split vertically or horizontally, and the flag mtt_split_binary, which determines whether to split into two or three, are referenced. mtt_split_vertical
al=1 indicates splitting vertically, mtt_split_vertical=0 indicates splitting horizontally, mtt_split_binary=1 indicates splitting into two, mtt_split_binary=0 indicates splitting into three. Hierarchical block splitting is performed by recursively calling multi_type_tree until mtt_split=0 is reached.

<Inter prediction>
The inter prediction method according to the embodiment is implemented by the inter prediction unit 10 of the video encoding device shown in FIG.
2 and is implemented in the inter prediction unit 203 of the video decoding device of FIG.

An inter prediction method according to an embodiment will be described with reference to the drawings. The inter prediction method is performed in both encoding and decoding processes on a coding block basis.

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

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

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

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

The inter prediction mode determination unit 305 determines the inter prediction mode based on the inter prediction information supplied from the normal prediction motion vector mode derivation unit 301, the normal merge mode derivation unit 302, the sub-block prediction motion vector mode derivation unit 303, and the sub-block merge mode derivation unit 304. The inter prediction mode determination unit 305 supplies inter prediction information according to the determination result to a motion compensation prediction unit 306.

The motion compensation prediction unit 306 stores the decoded image in the decoded image memory 1 based on the determined inter prediction information.
Inter prediction is performed on the reference image signal stored in 04. The detailed configuration and processing will be described later.

<Description of the Inter Prediction Unit 203 on the Decoding Side>
FIG. 22 is a diagram showing a detailed configuration of the inter prediction unit 203 of the video decoding device of FIG.

The normal prediction motion vector mode derivation unit 401 derives a plurality of normal prediction motion vector candidates, selects a prediction motion vector, and calculates a difference vector from the detected motion vector. The detected inter prediction mode, reference index, motion vector, and difference vector become inter prediction information of the normal prediction motion vector mode. This inter prediction information is output from the switch 408.
The normal prediction motion vector mode derivation unit 40
The detailed configuration and processing of No. 1 will be described later.

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

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

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

The motion compensation prediction unit 406 stores the decoded image in the decoded image memory 2 based on the determined inter prediction information.
08. The detailed configuration and processing are the same as those on the encoding side.

<Normal predicted motion vector mode derivation part (normal AMVP)>
The normal prediction motion vector mode derivation unit 301 in FIG. 17 includes a spatial prediction motion vector candidate derivation unit 321, a temporal prediction motion vector candidate derivation unit 322, and a history prediction motion vector candidate derivation unit 330.
23 , a motion vector predictor candidate supplementation unit 325 , a normal motion vector detection unit 326 , a motion vector predictor candidate selection unit 327 , and a motion vector subtraction unit 328 .

The normal predicted motion vector mode derivation unit 401 in FIG. 23 includes a spatial predicted motion vector candidate derivation unit 421, a temporal predicted motion vector candidate derivation unit 422, and a history predicted motion vector candidate derivation unit 4
23, a motion vector predictor candidate supplementation unit 425, a motion vector predictor candidate selection unit 426, and a motion vector addition unit 427.

The processing procedures of the normal prediction motion vector mode derivation unit 301 on the encoding side and the normal prediction motion vector mode derivation unit 401 on the decoding side will be described with reference to the flowcharts of Fig. 19 and Fig. 25. Fig. 19 is a flowchart showing the normal prediction motion vector mode derivation processing procedure by the normal motion vector mode derivation unit 301 on the encoding side, and Fig. 25 is a flowchart showing the normal prediction motion vector mode derivation processing procedure by the normal motion vector mode derivation unit 401 on the decoding side.

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

Next, the spatial prediction motion vector candidate derivation unit 321 and the temporal prediction motion vector candidate derivation unit 3
22, the history predicted motion vector candidate derivation unit 323, the predicted motion vector candidate supplement unit 325, the predicted motion vector candidate selection unit 327, and the motion vector subtraction unit 328 calculate the difference motion vector of the motion vector used in the inter prediction of the normal predicted motion vector mode for each of L0 and L1 (steps S101 to S106 in FIG. 19).
In the case where the inter prediction mode of the processing target block is L1 prediction (Pred_L0), a predicted motion vector candidate list mvpListL0 of L0 is calculated, a predicted motion vector mvpL0 is selected, and a differential motion vector mvdL0 of the motion vector mvL0 of L0 is calculated. In the case where the inter prediction mode of the processing target block is L1 prediction (Pred_L1), a predicted motion vector candidate list mvpListL1 of L1 is calculated, a predicted motion vector mvpL1 is selected, and a differential motion vector mvdL1 of the motion vector mvL1 of L1 is calculated. When the inter prediction mode of the block to be processed is bi-predictive (Pred_BI), both L0 prediction and L1 prediction are performed, an L0 predicted motion vector candidate list mvpListL0 is calculated, a L0 predicted motion vector mvpL0 is selected, a differential motion vector mvdL0 of the L0 motion vector mvL0 is calculated, and an L1 predicted motion vector candidate list mvpListL1 is calculated, a L1 predicted motion vector mvpL1 is calculated, and a differential motion vector mvdL1 of the L1 motion vector mvL1 is calculated.

Although the differential motion vector calculation process is performed for each of L0 and L1, the process is common to both L0 and L1. 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 differential motion vector of LX,
When referring to information in the other list rather than LX, the other list is represented as LY.

When the motion vector mvLX of LX is used (step S102 in FIG. 19: YES),
A candidate predictor motion vector for LX is calculated to construct a predictor motion vector candidate list mvpListLX for LX (step S103 in FIG. 19). A spatial predictor motion vector candidate derivation unit 321, a temporal predictor motion vector candidate derivation unit 322, a history predictor motion vector candidate derivation unit 323, and a predictor motion vector candidate supplementation unit 325 in the normal predictor motion vector mode derivation unit 301 derive multiple predictor motion vector candidates to construct the predictor motion vector candidate list mvpListLX.
The detailed process of step S103 will be described later with reference to the flowchart of FIG.

Next, the motion vector predictor candidate selection unit 327 selects a motion vector predictor mvpLX of LX from the motion vector predictor candidate list mvpListLX of LX (step S104 in FIG. 19).
A differential motion vector is calculated, which is the difference between the motion vector mvLX and each motion vector predictor candidate mvpListLX[i] stored in the motion vector predictor candidate list mvpListLX.
The amount of code required to encode these differential motion vectors is estimated by the motion vector candidate list mvpLis
Then, among the elements registered in the motion vector predictor candidate list mvpListLX, the motion vector predictor candidate with the smallest code amount for each motion vector predictor candidate is calculated.
Select mvpListLX[i] as the motion vector predictor mvpLX and obtain its index i. If there are multiple motion vector predictor candidates with the smallest amount of generated code in the motion vector predictor candidate list mvpListLX, select the motion vector predictor candidate mvpListLX[i] represented by the smallest index i in the motion vector predictor candidate list mvpListLX as the optimal motion vector predictor mvpLX and obtain its index i.

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

<Normal predicted motion vector mode derivation unit (normal AMVP): Decoding side explanation>
Next, a normal predicted motion vector mode process procedure on the decoding side will be described with reference to FIG. 25. On the decoding side, a spatial predicted motion vector candidate derivation unit 421 and a temporal predicted motion vector candidate derivation unit 4
22, a history prediction motion vector candidate derivation unit 423 and a prediction motion vector candidate supplementation unit 425,
A motion vector used in inter prediction of normal prediction motion vector mode is calculated for each of L0 and L1 (steps S201 to S206 in FIG. 25). Specifically, when the prediction mode PredMode of the processing target block is inter prediction (MODE_INTER) and the inter prediction mode of the processing target block is L0 prediction (Pred_L0), the predicted motion vector candidate list mvpListL0 of L0 is calculated, the predicted motion vector mvpL0 is selected, and the motion vector mvL0 of L0 is calculated. When the inter prediction mode of the processing target block is L1 prediction (Pred_L1), the predicted motion vector candidate list mvpListL1 of L1 is calculated, the predicted motion vector mvpL1 is selected, and the motion vector mvL1 of L1 is calculated. When the inter prediction mode of the block to be processed is bi-predictive (Pred_BI), both L0 prediction and L1 prediction are performed, the predicted motion vector candidate list mvpListL0 for L0 is calculated, the predicted motion vector mvpL0 for L0 is selected, and the motion vector mvL0 for L0 is calculated, while the predicted motion vector candidate list mvpListL1 for L1 is calculated, the predicted motion vector mvpL1 for L1 is calculated, and the motion vector mvL1 for L1 is calculated.

As in the coding side, the decoding side also performs motion vector calculation processing for each of L0 and L1, but the processing is common to both L0 and L1.
L1 is represented as a common LX. LX represents an inter prediction mode used for inter prediction of the coding block to be processed. In the process of calculating the motion vector of L0, X is 0, and L1
In the process of calculating the motion vector of LX, X is 1. Furthermore, when, during the process of calculating the motion vector of LX, information in another reference list is referenced instead of the same reference list as the target LX, the other reference list is represented as LY.

When the motion vector mvLX of LX is used (step S202 in FIG. 25: YES),
A candidate predictor motion vector for LX is calculated, and a predictor motion vector candidate list mvpListLX for LX is constructed (step S203 in FIG. 25). A spatial predictor motion vector candidate derivation unit 421, a temporal predictor motion vector candidate derivation unit 422, a history predictor motion vector candidate derivation unit 423, and a predictor motion vector candidate supplementation unit 425 in the normal predictor motion vector mode derivation unit 401 calculate multiple predictor motion vector candidates, and construct the predictor motion vector candidate list mvpListLX.
The detailed process of step S203 will be described later with reference to the flowchart of FIG.

Next, the motion vector predictor candidate selection unit 426 selects the motion vector predictor candidate list mvpListLX
The bitstream decoder 201 decodes and supplies the predicted motion vector index mv
The candidate motion vector predictor mvpListLX[mvpIdxLX] corresponding to pIdxLX is extracted as the selected motion vector predictor mvpLX (step S204 in FIG. 25).

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

<Normal predicted motion vector mode derivation unit (normal AMVP): Motion vector prediction method>
Figure 20 is a flowchart showing the processing steps of a normal prediction motion vector mode derivation process having functions common to the normal prediction motion vector mode derivation unit 301 of the video encoding device and the normal prediction motion vector mode derivation unit 401 of the video decoding device according to an embodiment of the present invention.

Normal prediction motion vector mode derivation unit 301 and normal prediction motion vector mode derivation unit 40
In the embodiment, the motion vector predictor candidate list mvpListLX is provided. The motion vector predictor candidate list mvpListLX has a list structure, and is provided with a storage area for storing a motion vector predictor index indicating a location in the motion vector predictor candidate list and a motion vector predictor candidate corresponding to the index as an element. The number of the motion vector predictor index starts from 0, and the motion vector predictor candidate is stored in the storage area of the motion vector predictor candidate list mvpListLX. In this embodiment, the motion vector predictor candidate list mvpListLX is assumed to be capable of registering at least two motion vector predictor candidates (inter prediction information). Furthermore, 0 is set to a variable numCurrMvpCand indicating the number of motion vector predictor candidates registered in the motion vector predictor candidate list mvpListLX.

The spatial motion vector predictor candidate derivation units 321 and 421 derive a candidate motion vector predictor from the adjacent block on the left side. In this process, a flag availableFlagLXA indicating whether or not the motion vector predictor candidate of the adjacent block on the left side (A0 or A1) is available, a motion vector mvLXA, and a reference index refIdxA are derived, and mvLXA is added to the motion vector predictor candidate list mvpListLX (step S301 in FIG. 20). Note that when L0, X is 0.
, L1, X is set to 1 (similarly below). Next, the spatial prediction motion vector candidate derivation unit 32
Steps S301 and S302 of FIG. 20 derive a candidate motion vector predictor from the adjacent block above (B0, B1, or B2). In this process, a flag availableFlagLXB indicating whether or not the candidate motion vector predictor from the adjacent block above is available, a motion vector mvLXB, and a reference index refIdxB are derived, and if mvLXA and mvLXB are not equal, mvLXB is added to the motion vector predictor candidate list mvpListLX (step S302 of FIG. 20).
The processes in S1 and S302 are common except for the positions and the number of neighboring blocks to be referenced.
, and a motion vector mvLXN and a reference index refIdxN (N is A or B, and so on below).

Next, the temporal motion vector predictor candidate derivation units 322 and 422 derive motion vector predictor candidates from coding blocks in pictures that are different in time from the current processing target picture. In this process, a flag availableFlagLXCol indicating whether or not a motion vector predictor candidate of a coding block in a picture that is different in time is available, and a motion vector mvLXCol
, the reference index refIdxCol and the reference list listCol are derived, and mvLXCol is added to the motion vector predictor candidate list mvpListLX (step S303 in FIG. 20).
The derivation process of 3 will be explained in detail later.

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

Next, the history motion vector predictor candidate derivation units 323 and 423 add the history motion vector predictor candidates registered in the history motion vector predictor candidate list HmvpCandList to the history motion vector predictor candidate list mvpListLX (step S304 in FIG. 20).
The registration process will be described in detail later with reference to the flow chart of FIG.

Next, the motion vector predictor candidate supplementation units 325 and 425 generate the motion vector predictor candidate list mv
Add a motion vector of a predetermined value, such as (0, 0), until pListLX is satisfied (S3 in FIG. 20).
05).

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

The normal merge mode derivation unit 402 in FIG. 24 includes a spatial merge candidate derivation unit 441 , a temporal merge candidate derivation unit 442 , an average merge candidate derivation unit 444 , a history merge candidate derivation unit 445 , a merge candidate supplementation unit 446 , and a merge candidate selection unit 447 .

FIG. 21 shows the normal merge mode derivation unit 302 of the video encoding device according to the embodiment of the present invention.
13 is a flowchart illustrating the procedure of a normal merge mode derivation process having a function common to the normal merge mode derivation unit 402 of the video decoding device and the normal merge mode derivation unit 402 of the video decoding device.

The steps are described below in order. In the following description, unless otherwise specified, the slice type slice_type is a B slice, but the description can also be applied to the case of a P slice. However, when the slice type slice_type is a P slice, only L0 prediction (Pred_L0) is available as an inter prediction mode, and L1 prediction (Pred_L1), bi-prediction (Pred_BI) are also available.
Since there is no L1, the processing related to L1 can be omitted.

The normal merge mode derivation unit 302 and the normal merge mode derivation unit 402 each include a merge candidate list mergeCandList. The merge candidate list mergeCandList has a list structure,
A merge index indicating the location in the merge candidate list and a storage area for storing the merge candidates corresponding to the index as elements are provided. The merge index number is 0.
The process starts from the merge candidate list mergeCandList, and the merge candidates are stored in the storage area of the merge candidate list mergeCandList. In the subsequent process, the merge index i
The merge candidates are represented by mergeCandList[i]. In this embodiment, the merge candidate list mergeCandList is capable of registering at least six merge candidates (inter prediction information). Furthermore, a variable numCurrMergeCand indicating the number of merge candidates registered in the merge candidate list mergeCandList is set to 0.

The spatial merge candidate derivation unit 341 and the spatial merge candidate derivation unit 441 derive spatial merge candidates A and B from the blocks adjacent to the left and above the processing target block from the coding information stored in the coding information storage memory 111 of the video coding device or the coding information storage memory 205 of the video decoding device, and create a merge candidate list mergeC of the derived spatial merge candidates.
andList (step S401 in FIG. 21). Here, N is defined to indicate either spatial merge candidates A, B or temporal merge candidate Col. The availableFlagN flag indicates whether inter prediction information of block N is available as spatial merge candidate N, the L0 reference index refIdxL0N and L1 reference index refIdxL1N of spatial merge candidate N, the L0 prediction flag predFlagL0N indicating whether L0 prediction is performed and the L1 prediction flag predFlagL1N indicating whether L1 prediction is performed, the motion vector mvL0N of L0, the motion vector mvL1 of L1, and the motion vector mvL2 of L2 are registered in the availableFlagN flag.
However, in this embodiment, since merging candidates are derived without referring to other coding blocks included in the block including the coding block to be processed, spatial merging candidates included in the block including the coding block to be processed are not derived.

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

It is assumed that the processing of the temporal merge candidate derivation unit 342 and the temporal merge candidate derivation unit 442 can be omitted in units of sequences (SPS), pictures (PPS), or slices.

Next, the history merge candidate derivation unit 345 and the history merge candidate derivation unit 445 add the history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList to the merge candidate list mergeCandList (step S403 in FIG. 21).
The detailed process of step 3 will be described later with reference to the flowchart of FIG.

Next, the average merge candidate derivation unit 344 and the average merge candidate derivation unit 444 derive average merge candidates from the merge candidate list mergeCandList, and register the derived average merge candidates in the merge candidate list mergeCandList (step S404 in FIG. 21).
The detailed process of step 04 will be described later with reference to the flow chart of FIG.

Next, the merge candidate supplementation unit 346 and the merge candidate supplementation unit 446 create a merge candidate list
The number of merge candidates registered in mergeCandList, numCurrMergeCand, is less than the maximum number of merge candidates, M
If the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than axNumMergeCand, an additional merge candidate is derived with the maximum number of merge candidates MaxNumMergeCand as an upper limit, and is registered in the merge candidate list mergeCandList (step S4 in FIG. 21).
05). With the maximum number of merge candidates (MaxNumMergeCand) as the upper limit, in the P slice, the prediction mode with a motion vector of (0, 0) with a different reference index is L0 prediction (Pred_L0).
In B slices, the motion vectors are added at different reference indices.
0,0) is added as a merge candidate whose prediction mode is bi-predictive (Pred_BI).

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

When the size (product of width and height) of a coding block is less than 32, the normal merge mode derivation unit 302 and the normal merge mode derivation unit 402 derive a merge candidate in a parent block of the coding block. Then, for all child blocks, the merge candidate derived in the parent block is used, but only when the size of the parent block is 32 or more and fits within the screen.

<Sub-block predictive motion vector mode derivation>
Sub-block predicted motion vector mode derivation will now be described.

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

First, an affine inheritance predicted motion vector candidate is derived in the affine inheritance predicted motion vector candidate derivation unit 361. The derivation of the affine inheritance predicted motion vector candidate will be described later in detail.

Next, an affine construction predicted motion vector candidate derivation unit 362 derives an affine construction predicted motion vector candidate. The derivation of an affine construction predicted motion vector candidate will be described later in detail.

Next, an affine-common predictor motion vector candidate derivation unit 363 derives an affine-common predictor motion vector candidate. The derivation of an affine-common predictor motion vector candidate will be described later in detail.

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

The sub-block predictor motion vector candidate selection unit 367 selects a sub-block predictor motion vector candidate from among the sub-block predictor motion vector candidates derived in the affine inheritance predictor motion vector candidate derivation unit 361, the affine construction predictor motion vector candidate derivation unit 362, and the affine identical predictor motion vector candidate derivation unit 363, based on the motion vector supplied from the sub-block motion vector detection unit 366.
The motion vector predictor unit 304 selects a sub-block motion vector predictor candidate, and supplies information about the selected sub-block motion vector predictor candidate to the inter prediction mode determination unit 305 and the difference calculation unit 368 .

The difference calculation unit 368 supplies the difference prediction motion vector obtained by subtracting the sub-block prediction motion vector selected by the sub-block prediction motion vector candidate selection unit 367 from the motion vector supplied from the sub-block motion vector detection unit 366 to the inter prediction mode determination unit 305.

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

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

Next, an affine construction predicted motion vector candidate derivation unit 462 derives an affine construction predicted motion vector candidate. The process of the affine construction predicted motion vector candidate derivation unit 462 is the same as the process of the affine construction predicted motion vector candidate derivation unit 362 in the encoding device of this embodiment.

Next, an affine-coincident predictor motion vector candidate is derived in the affine-coincident predictor motion vector candidate derivation unit 463. The process of the affine-coincident predictor motion vector candidate derivation unit 463 is the same as the process of the affine-coincident predictor motion vector candidate derivation unit 363 in the encoding device of this embodiment.

The sub-block predictive motion vector candidate selection unit 466 selects a sub-block predictive motion vector candidate from among the sub-block predictive motion vector candidates derived in the affine inheritance predictive motion vector candidate derivation unit 461, the affine construction predictive motion vector candidate derivation unit 462, and the affine identical predictive motion vector candidate derivation unit 463 based on the predictive motion vector index transmitted from the encoding device and decoded, and supplies information regarding the selected sub-block predictive motion vector candidate to the motion compensation prediction unit 406 and the addition calculation unit 467.

The addition calculation unit 467 adds the differential motion vector transmitted from the encoding device and decoded to the sub-block predictive motion vector selected by the sub-block predictive motion vector candidate selection unit 466, and supplies the generated motion vector to the motion compensation prediction unit 406.

<Derivation of Affine Inheritance Predicted Motion Vector Candidates>
The affine inheritance predicted motion vector candidate derivation unit 361 will be described. The affine inheritance predicted motion vector candidate derivation unit 461 is also the same as the affine inheritance predicted motion vector candidate derivation unit 361.
Same as 1.

Affine inheritance predicted motion vector candidates inherit the motion vector information of the control points.

Figure 30 is a diagram explaining the derivation of affine inheritance predicted motion vector candidates.

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

Specifically, a maximum of one affine mode is searched for from each of the blocks (A0, A1) adjacent to the left side of the block being processed and the blocks (B0, B1, B2) adjacent to the top side of the block being processed, and these are used as the affine inheritance predicted motion vector.

Figure 34 is a flowchart for deriving affine inheritance predicted motion vector candidates.

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

Next, the blocks (B0, B1, B2) adjacent to the upper side of the block to be processed are set as an upper group (step S3104), and it is determined whether the block including B0 is in the affine mode (step S3105).
If B0 is not in the affine mode (step S3105: NO), the affine mode used by B0 is obtained (step S3106), and the process ends. If B0 is not in the affine mode (step S3105: NO), the affine inheritance predicted motion vector candidate derivation target is set to B0->B1, and an attempt is made to obtain the affine mode from the block including B1. Furthermore, if B1 is not in the affine mode (step S310
5: NO), the target of deriving an affine inheritance predicted motion vector candidate is set to B1->B2, and an attempt is made to obtain an affine mode from a block including B2.

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

<Derivation of affine constructed predicted motion vector candidates>
The affine construction predicted motion vector candidate derivation unit 362 will be described. The affine construction predicted motion vector candidate derivation unit 462 will be described.
Same as 2.

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

Figure 31 is a diagram explaining the derivation of affine construction predicted motion vector candidates.

Affine constructed predicted motion vector candidates are obtained by constructing a new affine mode by combining motion vectors of spatially adjacent encoded and decoded blocks.

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

Figure 35 is a flowchart for deriving affine construction predicted motion vector candidates.

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

When selecting the three control points mode as the affine construction predicted motion vector (step S
If all three control points (CP0, CP1, CP2) have been derived (step S3203: YES), it is determined whether or not all three control points (CP0, CP1, CP2) have been derived (step S3203: YES).
P2) is used as the affine constructed predicted motion vector (step S32
04). If the three control points mode is not selected but the two control points mode is selected (step S3
If the result of step S3202 is NO, it is determined whether or not the two control points (CP0, CP1) have all been derived (step S3205). If the result of step S3205 is YES, an affine model using the two control points (CP0, CP1) is set as an affine constructed predicted motion vector (step S3206).

<Derivation of Affine Same Predictor Motion Vector Candidates>
The affine identical predictor motion vector candidate derivation unit 363 will be described. The affine identical predictor motion vector candidate derivation unit 463 is also the same as the affine identical predictor motion vector candidate derivation unit 363.
Same as 3.

The affine identical predictor motion vector candidates are obtained by deriving the same motion vector at each control point.

Specifically, similarly to the affine construction predicted motion vector candidate derivation units 362 and 462, each control point information is derived and all control points are set to the same one of CP0 to CP2, thereby obtaining the predicted motion vector. Also, similarly to the normal predicted motion vector mode, the predicted motion vector can be obtained by setting the derived temporal motion vector to all control points.

<Sub-block merge mode derivation>
Sub-block merge mode derivation will now be described.

FIG. 28 shows the sub-block merge mode derivation unit 304 in the encoding device of this embodiment.
The subblock merge mode derivation unit 304 includes a subblock merge candidate list subblockMergeCandList.
The subblock merge candidate list subblockMergeCandList has a list structure similar to that of the merge candidate list mergeCandList in , and is provided with a merge index indicating a location within the subblock merge candidate list, and a storage area for storing subblock merge candidates corresponding to the index as elements. In this embodiment, the subblock merge candidate list subblockMergeCandList is capable of registering at least five merge candidates (inter prediction information). However, each merge candidate is
Further, it has motion vector information for each subblock, or motion vector information for control points.

First, sub-block temporal merging candidates are derived in the sub-block temporal merging candidate derivation unit 381. The derivation of sub-block temporal merging candidates will be described later in detail.

Next, affine inheritance merge candidate derivation unit 382 derives affine inheritance merge candidates. The derivation of affine inheritance merge candidates will be described later in detail.

Next, affine construct merge candidates are derived in the affine construct merge candidate derivation unit 383. The derivation of affine construct merge candidates will be described later in detail.

Next, affine-fixed merging candidates are derived in the affine-fixed merging candidate derivation unit 385. The derivation of affine-fixed merging candidates will be described later in detail.

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

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

First, sub-block temporal merging candidates are derived in the sub-block temporal merging candidate derivation unit 481. The process of the sub-block temporal merging candidate derivation unit 481 is the same as the process of the sub-block temporal merging candidate derivation unit 381.

Next, the affine inheritance merge candidate derivation unit 482 derives affine inheritance merge candidates. The process of the affine inheritance merge candidate derivation unit 482 is the same as that of the affine inheritance merge candidate derivation unit 3.
This is the same as the process in 82.

Next, the affine construct merge candidate derivation unit 483 derives affine construct merge candidates. The process of the affine construct merge candidate derivation unit 483 is the same as that of the affine construct merge candidate derivation unit 3.
This is the same as the process in 83.

Next, the affine-fixed merge candidate derivation unit 485 derives affine-fixed merge candidates. The process of the affine-fixed merge candidate derivation unit 485 is the same as that of the affine-fixed merge candidate derivation unit 485.
This is the same as the process in 85.

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

When the size (product of width and height) of a coding block is less than 32, the sub-block merging mode derivation unit 304 and the sub-block merging mode derivation unit 404 derive sub-block merging candidates in the parent block of the coding block. Then, for all child blocks, the sub-block merging candidates derived in the parent block are used, however, only when the size of the parent block is 32 or more and fits within the screen.

<Sub-block Temporal Merging Candidate Derivation>
The operation of the sub-block temporal merging candidate derivation unit 381 will be described later.

<Affine inheritance merge candidate derivation>
The following describes the affine inheritance merge candidate derivation unit 382. The affine inheritance merge candidate derivation unit 482 is similar to the affine inheritance merge candidate derivation unit 382.

An affine inheritance merge candidate inherits the affine model of the control points from the affine models of spatially adjacent blocks.

32 is a diagram for explaining derivation of an affine inheritance merge candidate. The derivation of an affine inheritance merge mode candidate is obtained by searching for motion vectors of control points of spatially adjacent encoded and decoded blocks, similar to the derivation of an affine inheritance prediction motion vector.

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

Figure 36 is a flowchart for deriving affine inheritance merge candidates.

First, the block (A0, A1) adjacent to the left side of the block to be processed is set as a left group (step S3301), and it is determined whether the block including A0 is in the affine mode (step S3302). If A0 is in the affine mode (step S3102: YES),
If A0 is not in affine mode (step S3302: NO), the affine model used by A0 is obtained (step S3303), and the process proceeds to the adjacent block on the upper side.
The target of affine inheritance merge candidate derivation is A0->A1, and an attempt is made to obtain an affine mode from a block including A1.

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

<Affine Construction Merge Candidate Derivation>
The affine construct merge candidate derivation unit 383 will now be described. The affine construct merge candidate derivation unit 483 is similar to the affine construct merge candidate derivation unit 383.

33 is a diagram for explaining derivation of affine construct merge candidates. The affine construct merge candidates construct an affine model of control points from motion information of spatially adjacent blocks and a temporal coding block.

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

Figure 37 is a flowchart for deriving affine construction merge candidates.

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

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

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

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

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

Next, it is determined whether or not an affine model can be constructed using two control points based on the derived CP0 and CP1 (step S3410). If it is possible to construct an affine model (step S341
0: YES), the two-control-point affine model of CP0 and CP1 is set as an affine merge candidate (step S3411).

Next, it is determined whether or not an affine model can be constructed using the derived CP0 and CP2 by two control points (step S3412). If it can be constructed (step S341
2: YES), the two-control-point affine model of CP0 and CP2 is set as an affine merge candidate (step S3413).

Here, whether or not an affine model can be constructed is determined on the condition that at least the reference images of all control points are the same (affine transformation is possible).
Affine models other than the three-control-point affine model using CP2 and the two-control-point affine model using CP0 and CP1 are the three-control-point affine models.
For the three-control-point affine model by 2,
Convert to a two-control-point affine model using P1.

<Affine fixed merge candidate derivation>
The affine-anchored merging candidate derivation unit 385 will now be described. The affine-anchored merging candidate derivation unit 485 is similar to the affine-anchored merging candidate derivation unit 385.

Affine fixed merge candidates fix the motion information of the control points with the fixed motion information.

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

<Temporal prediction motion vector derivation>
Prior to the description of the temporal predicted motion vector, the temporal relationship of pictures will be described with reference to FIG.
49A shows the relationship between a current coding block and a coded picture that is temporally different from the current picture. A specific coded picture that is referred to in coding the current picture is defined as ColPic. ColPic is specified by syntax.

Also, Fig. 49(b) shows coded blocks in ColPic that are at the same position as the coding block to be processed and in the vicinity of the coding blocks. However, the coding blocks T0 and T1 shown in Fig. 49(b) are schematic, and the actual positions and sizes are not limited to these. Now, for the coding block to be processed, the position is (xCb, yCb) and the width is cbWidt.
Let h be the height and cbHeight be the height. And
xColBr = xCb + cbWidth
yColBr = yCb + cbHeight
The coding block on ColPic that includes the position ((xColBr >> 3) << 3, (yColBr >> 3) << 3) is T0.
xColCtr = xCb + (cbWidth >> 1)
yColCtr = yCb + (cbHeight >> 1)
The coding block on ColPic that includes the position ((xColCtr >> 3) << 3, (yColCtr >> 3) << 3) is set to T1.

The above description of the temporal relationship between pictures is for the encoding process, but the same applies to the decoding process. In other words, the above description of the decoding process can be applied in the same manner, with the encoding process replaced by the decoding process.

The operation of the temporal motion vector predictor candidate derivation unit 322 in the normal motion vector predictor mode derivation unit 301 in FIG. 17 will be described with reference to FIG.

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

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

Referring again to Fig. 50, after ColPic is derived, the coding block colCb is derived and coding information is obtained (step S4202). This process will be described with reference to Fig. 52.

First, in a picture ColPic of a different time, a coding block including the same lower right position as the coding block to be coded is set as a coding block colCb of a different time (step S
4221). An example of this coding block is shown in coding block T0 in FIG.

Next, the coding information of the coding block colCb at a different time is obtained (step S422
2) If the PredMode of the coding block colCb of the different time is unavailable or the prediction mode PredMode of the coding block colCb of the different time is intra prediction (MODE_INTRA) (step S4223: NO, step S4224: YES),
A coding block including the same central lower right position as the coding block to be processed within the image is set as a coding block colCb of a different time (step S4225). An example of this coding block is shown as a coding block T1 in FIG.

Referring again to FIG. 50, next, inter prediction information is derived for each reference list (steps S4203 and S4204). Here, for the coding block colCb, a motion vector mvLXCol for each reference list and a flag availableFlagLXCol indicating whether coding information is available or not are
LX indicates a reference list, and LX becomes L0 in the derivation of reference list 0, and LX becomes L1 in the derivation of reference list 1. The derivation of inter prediction information will be described with reference to FIG.

When the coding block colCb of a different time cannot be used (step S4231: NO)
or when the prediction mode PredMode is intra prediction (MODE_INTRA) (step S4232
: NO), and set both the flag availableFlagLXCol and the flag predFlagLXCol to 0 (step S
The motion vector mvLXCol is set to (0,0) (step S4234), and the process ends.

If the coding block colCb is available (step S4231: YES), and the prediction mode PredMod
If e is not intra prediction (MODE_INTRA) (Step S4232: YES), mvCol, refIdxCol, and availableFlagCol are calculated in the following procedure.

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

On the other hand, if the L0 prediction flag PredFlagL0[xPCol][yPCol] of the coding block colCb is not 0 (step S4235: NO), the L1 prediction flag PredFlagL1[xP
Col][yPCol] is checked to see if it is 0.
If the value of [xPCol][yPCol] is 0 (step S4239: YES), the motion vector mvCol is set to the same value as the L0 motion vector MvL0[xPCol][yPCol] of the coding block colCb (step S4240), and the reference index refIdxCol is set to the L0 reference index RefIdxL0[xP
Col][yPCol] (step S4241), and the reference list listCol is set to L0 (step S4242).

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

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

First, it is determined whether the POCs of all pictures registered in all reference lists are smaller than the POC of the current picture to be processed (step S4251).
P of all pictures registered in L0 and L1, which are all reference lists of colCb
If the OC is smaller than the POC of the current picture to be processed (step S4251: YES),
), if LX is L0, i.e., if a predicted vector candidate for the motion vector of L0 of the coding block to be processed is derived (step S4252: YES), the inter prediction information of the L0 side of the coding block colCb is selected, and if LX is L1, i.e., if a predicted vector candidate for the motion vector of L1 of the coding block to be processed is derived (step S4252: NO), the inter prediction information of the L1 side of the coding block colCb is selected.
If at least one of the POCs of the pictures registered in all reference lists L0 and L1 is larger than the POC of the current picture to be processed (step S4251: NO), and if the flag collocated_from_l0_flag is 0 (step S4253: YES), the inter-prediction information of L0 of the coding block colCb is selected, and if the flag collocated_from_l0_flag is 1 (step S4253: NO), the inter-prediction information of L1 of the coding block colCb is selected.

When selecting inter prediction information for L0 of coding block colCb (step S42
52: YES, or step S4253: YES), the motion vector mvCol is MvL0[xPCol]
[yPCol] is set to the same value as RefIdxCol (step S4254), and the reference index refIdxCol is
The list listCol is set to the same value as L0[xPCol][yPCol] (step S4255).
(step S4256).

When selecting inter prediction information for L1 of the coding block colCb (step S42
52: NO, or step S4253: NO), the motion vector mvCol is MvL1[xPCol][yPC
ol] (step S4257), and the reference index refIdxCol is set to the same value as RefIdxL1
The value is set to the same as [xPCol][yPCol] (step S4258), and the list listCol is set to L1 (step S4259).

Returning to FIG. 53, when inter prediction information is obtained from the coding block colCb, the flag ava
Both ilableFlagLXCol and flag predFlagLXCol are set to 1 (step S4244).

Next, the motion vector mvCol is scaled to obtain a motion vector mvLXCol (step S4245). The procedure for the scaling calculation process of the motion vector mvLXCol will be described with reference to FIG.

The inter-picture distance td is calculated by subtracting the POC of the reference picture corresponding to the reference index refIdxCol referred to in the list listCol of the coding block colCb from the POC of the picture ColPic at a different time.
td = [POC of ColPic at different times] - [List of coding blocks colCb
POC of reference picture referenced in listCol]
(Step S4261). Note that, when the POC of the reference picture referred to in the list listCol of the coding block colCb is earlier in the display order than the picture ColPic at a different time, the inter-picture distance td has a positive value, and when the POC of the reference picture referred to in the list listCol of the coding block colCb is later in the display order than the picture ColPic at a different time, the inter-picture distance td has a negative value.

Next, the POC of the reference picture referred to by the list LX of the current picture to be processed is subtracted from the POC of the current picture to be processed to obtain an inter-picture distance tb.
tb = [POC of the current picture to be processed] - [POC of the reference picture corresponding to the reference index of the LX of the temporal merge candidate]
Note that, when the reference picture referred to in the list LX of the current picture to be processed is earlier in the display order than the current picture to be processed, the inter-picture distance tb has a positive value, and when the reference picture referred to in the list LX of the current picture to be processed is later in the display order, the inter-picture distance tb has a negative value.

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

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

Referring again to FIG. 50, the motion vector mvL0Col of L0 is added as a candidate to the motion vector predictor candidate list mvpListLX in the normal motion vector predictor mode derivation unit 301 (step S4205). However, this addition is only made when the flag availableFlagL0Col=1, which indicates whether the coding block colCb of the reference list 0 is valid or not.
The motion vector mvL1Col is added as a candidate to the motion vector predictor candidate list mvpListLX in the normal motion vector predictor mode derivation unit 301 (step S4205). Note that this addition is performed in accordance with the flag available indicating whether the coding block colCb in the reference list 1 is valid or not.
This is only the case when eFlagL1Col = 1. With the above, the process of the temporal motion vector predictor candidate derivation unit 322 ends.

The above description of the normal prediction motion vector mode derivation unit 301 is for encoding, but the same applies to decoding. That is, the operation of the temporal prediction motion vector candidate derivation unit 422 in the normal prediction motion vector mode derivation unit 401 in Fig. 23 can be similarly described by replacing encoding in the above description with decoding.

<Deriving Temporal Merge Candidates>
The operation of the temporal merge candidate derivation unit 342 in the normal merge mode derivation unit 302 in FIG. 18 will be described with reference to FIG.

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

Next, a flag, availableFlagCol, indicating whether the coding block colCb is available or not is calculated (
Step S4305. If the flag availableFlagL0Col or the flag availableFlagL1Col is
If it is 1, availableFlagCol will be 1. Otherwise, availableFlagCol will be 0.

Then, the motion vector mvL0Col of L0 and the motion vector mvL1Col of L1 are added as candidates to the merge candidate list mergeCandList in the normal merge mode derivation unit 302 described above (step S4306). However, this addition is only made when the flag indicating whether the coding block colCb is available or not is availableFlagCol=1.
Processing of 2 is terminated.

The above description of the temporal merge candidate derivation unit 342 is for encoding, but the same is true for decoding. That is, the operation of the temporal merge candidate derivation unit 442 in the normal merge mode derivation unit 402 in Fig. 24 can be similarly described by replacing encoding in the above description with decoding.

<Updating the Historical Motion Vector Predictor Candidate List>
Next, the coding information storage memory 111 on the coding side and the coding information storage memory 20 on the decoding side
A method for initializing and updating the historical motion vector predictor candidate list HmvpCandList in preparation for V.5 will be described in detail below. Fig. 38 is a flowchart illustrating the procedure of the historical motion vector predictor candidate list initialization/update process.

In this embodiment, the history prediction motion vector candidate list HmvpCandList is updated in the coding information storage memory 111 and the coding information storage memory 205. A history candidate list update unit may be provided in the inter prediction unit 102 and the inter prediction unit 203 to update the history prediction motion vector candidate list HmvpCandList.

The historical prediction motion vector candidate list HmvpCandList is initially set at the beginning of a slice, and on the encoding side, the historical prediction motion vector candidate list HmvpCandList is updated when the prediction method determination unit 105 selects the normal prediction vector mode or the normal merge mode, and on the decoding side, the historical prediction motion vector candidate list HmvpCandList is updated when the inter prediction mode decoded by the bit string decoding unit 201 is the normal prediction vector mode or the normal merge mode.

When performing inter prediction in the normal prediction vector mode or the normal merge mode, the inter prediction information used is stored as an inter prediction information candidate hMvpCand in the history prediction motion vector candidate list.
The inter-prediction information candidate hMvpCand is registered in the HmvpCandList.
refIdxL0 and an L1 reference index refIdxL1, an L0 prediction flag predFlagL0 indicating whether or not L0 prediction is performed, and an L1 prediction flag predFlagL1 indicating whether or not L1 prediction is performed;
The motion vector mvL0 of L0 and the motion vector mvL1 of L1 are included. The elements (i.e., inter prediction information) registered in the historical predicted motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side include
If there is inter prediction information with the same value as the inter prediction information candidate hMvpCand, the element is deleted from the historical motion vector predictor candidate list HmvpCandList. On the other hand, if there is no inter prediction information with the same value as the inter prediction information candidate hMvpCand, the first element of the historical motion vector predictor candidate list HmvpCandList is deleted, and the historical motion vector predictor candidate list HmvpCand
The inter-prediction information candidate hMvpCand is added to the end of List.

The encoding information storage memory 111 on the encoding side and the encoding information storage memory 2 on the decoding side according to the present invention
The number of elements in the historical motion vector predictor candidate list HmvpCandList provided for 05 is six.

First, a historical motion vector predictor candidate list HmvpCandList is initialized in units of slices (step S2101 in FIG. 38).
All elements of vpCandList are emptied, and the value of the number NumHmvpCand of historical motion vector predictor candidates registered in the historical motion vector predictor candidate list HmvpCandList is set to 0.

Note that, although the initialization of the historical motion vector predictor candidate list HmvpCandList is performed on a slice-by-slice basis (the first coding block of a slice), it may be performed on a picture-by-picture basis, a tile-by-tile basis, or a tree block row-by-tree block basis.

Next, for each coding block in the slice, the following historical motion vector predictor candidate list Hmvp
The process of updating the CandList is repeated (steps S2102 to S2107 in FIG. 38).

First, the initial setting is performed for each coding block. The flag "identicalCandExist" indicating whether an identical candidate exists or not is set to FALSE, and the deletion target index "removeIdx" is set to 0.
(step S2103 in FIG. 38).

Inter prediction information candidate hMvp to be registered in the history prediction motion vector candidate list HmvpCandList
It is determined whether Cand exists (step S2104 in FIG. 38). When the prediction method determination unit 105 on the encoding side determines that the normal prediction motion vector mode or the normal merge mode is selected,
Or, if the bitstream decoding unit 201 on the decoding side decodes as normal prediction motion vector mode or normal merge mode, the inter prediction mode is set to hMvpCand. If the prediction method determination unit 105 on the encoding side determines as intra prediction mode, sub-block prediction motion vector mode, or sub-block merge mode, or if the bitstream decoding unit 201 on the decoding side decodes as intra prediction mode, sub-block prediction motion vector mode, or sub-block merge mode, the update process of the history prediction motion vector candidate list HmvpCandList is not performed, and the inter prediction information candidate hMvpCand to be registered does not exist. If the inter prediction information candidate hMvpCand to be registered does not exist, steps S2105 to S2106 are skipped (step S2104 in FIG. 38: NO). If the inter prediction information candidate hMvpCand to be registered exists, the process from step S2105 onwards is performed (step S2104 in FIG. 38: YES).
.

Next, it is determined whether or not an element identical to the inter-prediction information candidate hMvpCand to be registered exists among the elements of the history motion vector predictor candidate list HmvpCandList (step S2105 in FIG. 38). FIG. 39 is a flowchart of the procedure of the identical element confirmation process. When the value of the number of history motion vector predictor candidates NumHmvpCand is 0 (step S2121 in FIG. 39: NO),
The historical predicted motion vector candidate list HmvpCandList is empty and there is no identical candidate.
If the value of the number of historical motion vector predictor candidates NumHmvpCand is greater than 0 (step S2
121: YES), and repeat the process of step S2123 for the history predicted motion vector index hMvpIdx from 0 to NumHmvpCand-1 (steps S2122 to S2125 in FIG. 39).
First, the hMvpIdx-th element HmvpCandList, counting from 0 in the history motion vector predictor candidate list,
t[hMvpIdx] is compared with the inter-prediction information candidate hMvpCand to see if it is the same (step S2123 in FIG. 39). If they are the same (step S2123 in FIG. 39: YES), a flag identicalCandExist indicating whether an identical candidate exists is set to TRUE, the deletion target index removeIdx is set to the value of hMVpIndex, and this identical element confirmation process is terminated. If they are not the same (step S2123 in FIG. 39: NO), hMvpIdx is incremented by 1, and if the historical predicted motion vector index hMvpIdx is equal to or less than NumHmvpCand-1, the processes from step S2123 onward are performed (steps S2122 to S2125 in FIG. 39).

Returning to the flowchart of Fig. 38 again, a process of shifting and adding elements of the historical motion vector predictor candidate list HmvpCandList is performed (step S2106 of Fig. 38). Fig. 40 is a flowchart of the process procedure of shifting/adding elements of the historical motion vector predictor candidate list HmvpCandList in step S2106 of Fig. 38. First, it is determined whether to remove elements stored in the historical motion vector predictor candidate list HmvpCandList and then add new elements, or to add new elements without removing elements. Specifically, a flag identicalC indicating whether an identical candidate exists is set to 0.
A comparison is made to see whether andExist is TRUE or NumHmvpCand is 6 (step S21 in FIG. 40).
41) The flag identicalCandExist, which indicates whether an identical candidate exists, is TRUE or
If NumHmvpCand satisfies any one of the six conditions (step S2141 in FIG. 40: YES)
, elements stored in the historical motion vector predictor candidate list HmvpCandList are removed, and then a new element is added. The initial value of index i is set to the value of removeIdx + 1. The element shifting process of step S2143 is repeated from this initial value to NumHmvpCand (steps S2142 to S2144 in FIG. 40). The elements of HMVPCandList[i] are shifted forward by copying them to HMVPCandList[i - 1] (step S2143 in FIG. 40), and i is incremented by 1 (steps S2142 to S2144 in FIG. 40). When index i is equal to NumHmvp
When the element shift process in step S2143 is completed, the inter prediction information candidate hMvpCand is added to the end of the history predicted motion vector candidate list (step S2 in FIG. 40).
145). Here, the end of the history motion vector predictor candidate list is the end of the history motion vector predictor candidate list (NumHmvp
Cand-1)-th HMVPCandList[NumHmvpCand-1]. This completes the element shift and addition process for the historical motion vector predictor candidate list HMVPCandList. On the other hand, if neither of the conditions that the flag identicalCandExist indicating whether or not an identical candidate exists is TRUE (true) and NumHmvpCand is 6 is satisfied (step S2141 in FIG. 40: NO), the inter prediction information candidate hMvpCand is added to the end of the historical motion vector predictor candidate list without removing the elements stored in the historical motion vector predictor candidate list HmvpCandList (step S2146 in FIG. 40). Here, the end of the historical motion vector predictor candidate list refers to the NumHmvpCand-th HMVPCandList counting from 0.
andList[NumHmvpCand]. Furthermore, NumHmvpCand is incremented by 1, and the element shift/addition process of the historical motion vector predictor candidate list HMVPCandList ends.

43 is a diagram for explaining an example of a process of updating a history prediction motion vector list. When six elements (inter prediction information) are registered in the history prediction motion vector candidate list HMVPCandList, in order to add new inter prediction information, the history prediction motion vector candidate list HMVP
Each element of CandList is compared with new inter prediction information from the front ( FIG. 43( a )). If the new inter prediction information has the same value as the third element HMVP2 from the top of the historical motion vector predictor candidate list HMVPCandList, the element HMV
P2 is deleted, and the elements HMVP3 to HMVP5 are shifted (copied) one by one forward. New inter prediction information is added to the end of the historical predicted motion vector candidate list HMVPCandList (see FIG. 43).
(b)), and then updating of the historical motion vector predictor candidate list HMVPCandList is completed (FIG. 43(c)
)).

<Historical Prediction Motion Vector Candidate Deriving Process>
Next, a detailed description will be given of a method for deriving a historical prediction motion vector candidate from the historical prediction motion vector candidate list HMVPCandList, which is a processing procedure of step S304 in Fig. 20 and is common to the historical prediction motion vector candidate derivation unit 323 of the normal prediction motion vector mode derivation unit 301 on the encoding side and the historical prediction motion vector candidate derivation unit 423 of the normal prediction motion vector mode derivation unit 401 on the decoding side. Fig. 41 is a flowchart illustrating the historical prediction motion vector candidate derivation processing procedure.

The number of current motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpList
t The maximum number of elements in LX (here, 2) or more, or the number of historical motion vector predictor candidates NumHmvp
If the value of Cand is 0 (step S2201 in FIG. 41: NO),
The processes from S2202 to S2209 are omitted, and the procedure for deriving a historical motion vector predictor candidate is terminated.
The number of current motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpListL
If the number of elements in X is smaller than 2, and the number of historical motion vector predictor candidates NumHmvpCand
If the value is greater than 0 (step S2201 in FIG. 41: YES),
The process goes from S2202 to S2209.

Next, the processes of steps S2203 to S2208 in FIG. 41 are repeated from the index i of 0 to the smaller value of either 3 or the number NumHmvpCand of historical motion vector predictor candidates (
Steps S2202 to S2209 in FIG. 41). The number of current motion vector predictor candidates, numCurrM
When vpCand is equal to or greater than 2, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX (see FIG. 4 ),
41 ), the processes of steps S2204 to S2209 in FIG. 41 are omitted, and the history motion vector predictor candidate derivation process procedure is terminated.
If it is smaller (step S2203 in FIG. 41: YES), step S2204 in FIG.
The following process is carried out.

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

Next, if the reference index of LY in the historical motion vector predictor candidate list HmvpCandList[i] is the same as the reference index refIdxLX of the motion vector to be encoded/decoded (step S2206 in FIG. 41: YES), the numCurrMvpCand-th element mvpListLX[numCurrMvpCand
The LY motion vector of the history motion vector predictor candidate HmvpCandList[i] is added to the history motion vector predictor candidate list HmvpCandList[i] (step S2207 in FIG. 41 ), and the number of current motion vector predictor candidates numCurrMvpCand is incremented by 1.
If it is not the same as the reference index refIdxLX of the motion vector to be coded/decoded (step S2206: NO in FIG. 41), the additional process of step S2207 is skipped.

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

The index i is incremented by 1, and if the index i is equal to or less than the smaller value of 3 or the number NumHmvpCand of historical motion vector predictor candidates, the processes from step S2203 onwards are performed again (steps S2202 to S2209 in FIG. 41).

<History Merge Candidate Deriving Process>
Next, a detailed description will be given of a method for deriving history merge candidates from the history merge candidate list HmvpCandList, which is a processing procedure of step S404 in Fig. 21 and is common to the history merge candidate derivation unit 345 of the normal merge mode derivation unit 302 on the encoding side and the history merge candidate derivation unit 445 of the normal merge mode derivation unit 402 on the decoding side. Fig. 42 is a flowchart illustrating the history merge candidate derivation processing procedure.

First, an initialization process is performed (step S2301 in FIG. 42).
The value of FALSE is set for each (rrMergeCand -1)th element, and the variable numOrigMergeCand is set to the number of elements currently registered in the merge candidate list, numCurrMergeCand.

Next, the initial value of the index hMvpIdx is set to 1, and the addition process from step S2303 to step S2310 in FIG. 42 is repeated from this initial value to NumHmvpCand (FIG. 4
42 , steps S2302 to S2311). If the number of elements registered in the current merge candidate list, numCurrMergeCand, is not equal to or less than the maximum number of merge candidates, MaxNumMergeCand-1, merge candidates have been added to all elements in the merge candidate list, so this history merge candidate derivation process is terminated (step S2303 in FIG. 42 : NO). If the number of elements registered in the current merge candidate list, numCurrMergeCand, is equal to or less than the maximum number of merge candidates, MaxNumMergeCand-1 (step S2303 in FIG. 42 : YES), the process proceeds to step S2304 and thereafter.

First, the value FALSE is set to sameMotion (step S2304 in FIG. 42). Next, the initial value of index i is set to 0, and the index i is incremented from this initial value to 1 in step S2304 in FIG. 42.
The process goes to S2306 and S2307 (S2305 to S2308 in FIG. 42).

Next, a comparison is made as to whether the (NumHmvpCand-hMvpIdx)th element HmvpCandList[NumHmvpCand-hMvpIdx], counting from 0, of the history motion vector prediction candidate list is the same as the i-th element mergeCandList[i], counting from 0, of the merge candidate list (step S2306 in FIG. 42).
It indicates that the values of hMvpIdx (reference index, motion vector) are the same. However, the process of step S2306 is performed only when hMvpIdx is greater than NumHmvpCand-2, mergeCandList[i] is a spatial merge candidate, and isPruned[i] is FALSE. If the values are the same (step S2306 in FIG. 39: YES), sameMotion and isPruned[i] are both set to TRUE (step S2307 in FIG. 42). If the values are not the same (step S2306 in FIG. 39: NO),
When the repeated processes from step S2305 to step S2308 in FIG. 42 are completed, a comparison is made to see if sameMotion is FALSE (step S2309 in FIG. 42). If sameMotion is FALSE (step S2309 in FIG. 42: YES), the numCurrMergeCand-th mergeCandList[nu
mCurrMergeCand], counting from 0 in the history prediction motion vector candidate list (NumHmvpCand - hMvp
The CPU 11 adds the (NumHmvpCand - hMvpIdx)-th element HmvpCandList[NumHmvpCand - hMvpIdx] and increments numCurrMergeCand by 1 (step S2310 in FIG. 42). The index hMvpIdx is incremented by 1 (step S2302 in FIG. 42), and steps S2302 to S2311 in FIG. 42 are repeated.

When all elements in the history motion vector predictor candidate list have been checked, or when merge candidates have been added to all elements in the merge candidate list, this history merge candidate derivation process is completed.

<Average Merge Candidate Derivation Process>
Next, a detailed description will be given of a method for deriving an average merge candidate, which is a processing procedure of step S403 in Fig. 21 and is common to the average merge candidate derivation unit 344 of the normal merge mode derivation unit 302 on the encoding side and the average merge candidate derivation unit 444 of the normal merge mode derivation unit 402 on the decoding side. Fig. 62 is a flowchart illustrating the processing procedure for deriving an average merge candidate.

First, an initialization process is performed (step S1301 in FIG. 62). The number of elements currently registered in the merge candidate list, numCurrMergeCand, is set in the variable numOrigMergeCand.

Next, the merge candidate list is scanned from the top to determine two pieces of motion information. The first piece of motion information is designated as index i=0, and the second piece of motion information is designated as index j=1. (
Steps S1302 to S1303 in FIG. 62. If the number of elements registered in the current merge candidate list, numCurrMergeCand, is not equal to or less than the maximum number of merge candidates, MaxNumMergeCand-1, then merge candidates have been added to all elements in the merge candidate list, and this history merge candidate derivation process is terminated (Step S1304 in FIG. 62). If the number of elements registered in the current merge candidate list, numCurrMergeCand, is equal to or less than the maximum number of merge candidates, MaxNumMergeCand-1, then the process from step S1305 onwards is carried out.

It is determined whether or not the i-th motion information mergeCandList[i] of the merge candidate list and the j-th motion information mergeCandList[j] of the merge candidate list are both invalid (step S130 in FIG. 62).
5), if both are invalid, the average merge candidate of mergeCandList[i] and mergeCandList[j] is not derived, and the process moves to the next element. If both mergeCandList[i] and mergeCandList[j] are not invalid, the following process is repeated with X set to 0 and 1 (steps S1306 to S1309 in FIG. 62).
1314).

Determine whether the LX prediction of mergeCandList[i] is valid (step S1307 in FIG. 62).
If the LX prediction of mergeCandList[i] is valid, it is determined whether the LX prediction of mergeCandList[j] is valid (step S1308 in FIG. 62). If the LX prediction of mergeCandList[j] is valid, that is, if both the LX predictions of mergeCandList[i] and mergeCandList[j] are valid, the motion vector of the LX prediction obtained by averaging the motion vector of the LX prediction of mergeCandList[i] and the motion vector of the LX prediction of mergeCandList[j] and the average merge candidate of the LX prediction having the reference index of the LX prediction of mergeCandList[i] are derived and set as the LX prediction of averageCand, and the average merge candidate of the LX prediction having the reference index of the LX prediction of mergeCandList[i] is set as the LX prediction of averageCand.
The LX prediction of geCand is enabled (step S1309 in FIG. 62).
In step 08, if the LX prediction of mergeCandList[j] is not valid, i.e., the LX prediction of mergeCandList[i] is not valid.
If the prediction is valid and the LX prediction of mergeCandList[j] is invalid,
Derive the average merge candidate of the LX prediction with the motion vector and reference index of the prediction, and
The LX prediction of ageCand is set to the LX prediction of averageCand, and the LX prediction of averageCand is enabled (step S13 in FIG. 62).
10) In step S1307 of FIG. 62, if the LX prediction of mergeCandList[i] is not valid,
Determine whether the LX prediction of mergeCandList[j] is valid (step S1311 in FIG. 62).
If the LX prediction of mergeCandList[j] is valid, that is, if the LX prediction of mergeCandList[i] is invalid and the LX prediction of mergeCandList[j] is valid, the average merge candidate of the LX prediction having the motion vector and reference index of the LX prediction of mergeCandList[j] is derived and averageC
and sets the LX prediction of averageCand to valid (step S1312 in FIG. 62).
In step S1311 of FIG. 62, if the LX prediction of mergeCandList[j] is not valid, that is, if both the LX prediction of mergeCandList[i] and the LX prediction of mergeCandList[j] are invalid,
LX prediction of averageCand is disabled (step S1312 in FIG. 62).

Here, LX prediction is valid when the reference index refIdxLX is equal to or greater than 0. When LX prediction is invalid, that is, does not exist, the reference index refIdxLX is set to -1.

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

Note that the average merge candidate is averaged over the horizontal component of the motion vector and the vertical component of the motion vector.

<Sub-block Temporal Merging Candidate Derivation>
The operation of the sub-block temporal merging candidate derivation unit 381 in the sub-block merging mode derivation unit 304 in FIG. 16 will be described with reference to FIG.

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

If the coding block is smaller than 8x8 pixels (step S4002: YES), the flag indicating the presence of sub-block temporal merging candidates is set to availableFlagSbCol=0 (step S400
3), the process of the sub-block temporal merge candidate derivation unit is terminated. Here, if temporal motion vector prediction is prohibited by the syntax, or if sub-block temporal merge is prohibited, if the coding block is less than 8x8 pixels (step S4002:
YES) is processed in the same manner.

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

The process of deriving adjacent motion information of a coding block will be described with reference to FIG.
The process of deriving adjacent motion information is similar to the process of the spatial prediction motion vector candidate derivation unit 321. However, the order of searching for adjacent blocks is A0, B0, B1, A1, and B2 is not searched. First, the coding information is obtained for adjacent block n=A0 (step S4052).
The coding information indicates a flag availableFlagN indicating whether or not a neighboring block is available, a reference index refIdxLXN for each reference list, and a motion vector mvLXN.

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

If the adjacent block n is valid (step S4054: YES), the reference index ref
IdxLXN is set as the reference index refIdxLXn of the adjacent block n (step S4056).
Also, the motion vector mvLXN is set as the motion vector mvLXn of the adjacent block n (step S4
056), the process of deriving adjacent motion information for blocks is completed.

On the other hand, if the adjacent block n is invalid (step S4054: NO), the adjacent block n=B
0, obtain coding information (step S4052), and determine whether adjacent block n is valid or invalid (step S4054). Thereafter, similar processing is performed to loop in the order of B1, A1. The process of deriving adjacent motion information loops until the adjacent blocks are valid, and if all adjacent blocks A0, B0, B1, and A1 are invalid, the process of deriving adjacent motion information of blocks ends.

Again, refer to Figure 44. Once the adjacent motion information has been derived (step S4004), a temporal motion vector is derived (step S4006).

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

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

On the other hand, if the adjacent motion information is valid (step S4064: YES), it is determined whether or not a flag predFlagL1N indicating whether or not L1 prediction is used in the adjacent block N is 1 (step S4066). If predFlagL1N=0 (step S4066: NO), the next process (
If predFlagL1N=1 (step S4066: YES),
It is determined whether the POCs of all pictures registered in all reference lists are equal to or less than the POC of the current picture to be processed (step S4068). If the determination is true (step S4068: YES), the process proceeds to the next step (step S4070).

If the slice type slice_type is a B slice and the flag collocated_from_l0_flag is 0 (step S4070: YES, step S4072: YES), it is determined whether ColPic is the same as the reference picture RefPicList1[refIdxL1N] (the picture with the reference index refIdxL1N in the reference list L1) (step S4074).
4074: YES), and the temporal motion vector tempMv is set to mvL1N (step S4076
If this determination is false (step S4074: NO), the next process (step S4078
) The slice type slice_type is not a B slice, and the flag collocated_from_l0_f
If lag is not 0 (step S4070: NO or step S4072: NO),
Proceed to the next process (step S4078).

A flag predFlagL0N indicating whether L0 prediction is used in the adjacent block N
It is determined whether predFlagL0N=1 (step S4078).
78: YES), and it is determined whether ColPic is the same as the reference picture RefPicList0[refIdxL0N] (the picture with the reference index refIdxL0N in the reference list L0) (step S4080).
If this determination is true (step S4080: YES), the temporal motion vector tempMv=m
vL0N (step S4082). If this determination is false (step S4080: NO),
Then, the process of deriving the temporal motion vector is completed.

44 will be referred to again. Next, ColPic is derived (step S4016). This process is the same as S4201 in the temporal motion vector predictor candidate derivation unit 322, and therefore a description thereof will be omitted.

Then, a coding block colCb of a different time is set (step S4017). In this step, a coding block located at the same position as the coding block to be processed in the picture ColPic of the different time is set as colCb. This coding block corresponds to coding block T1 in FIG.

Next, the position obtained by adding the temporal motion vector tempMv to the coding block colCb is set as a new colCb (step S4018).
lCb, yColCb), and the temporal motion vector tempMv with 1/16 pixel accuracy (tempMv[0], tempMv[1])
And,
xColCb = Clip3( xCtb, xCtb + CtbSizeY + 3, xColCb + ( tempMv[0] >> 4 ) )
yColCb = Clip3( yCtb, yCtb + CtbSizeY - 1, yColCb + ( tempMv[1] >> 4 ) )
Here, the position of the top left corner of the tree block is (xCtb, yCtb), and the size of the tree block is CtbSizeY. The coding block on ColPic that includes the position ((xColCb >> 3) << 3, (yColCb >> 3) << 3) becomes the new colCb. As shown in the above formula, the position after adding tempMv is t
The position is corrected to within a range of about the size of the tree block so that it does not deviate significantly from the position before empMv is added. If this position is outside the screen, it is corrected to within the screen.

The prediction mode PredMode of this coding block colCb is inter prediction (MODE_INTER
If the prediction mode of colCb is not inter prediction (step S4020: NO), a flag av
The ailableFlagSbCol is set to 0 (step S4003), and the process of the sub-block temporal merging candidate derivation unit is terminated.

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

When the coding block colCb of a different time cannot be used (step S4112: NO)
or when the prediction mode PredMode is intra prediction (MODE_INTRA) (step S4114
: NO), and set both the flag availableFlagLXCol and the flag predFlagLXCol to 0 (step S
The process then proceeds to step S4116, and the motion vector mvCol is set to (0, 0) (step S4118), and the process of deriving the inter prediction information is terminated.

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

A flag PredFlagLX[xPCo
If mvLX[xPCol][yPCol] is 1 (step S4120: YES), the motion vector mvCol is set to the same value as MvLX[xPCol][yPCol], which is the motion vector of LX of the coding block colCb (step S4122), and the reference index refIdxCol is set to the reference index RefIdxLX[xPCol] of LX.
[yPCol] (step S4124), and the list listCol is set to LX (step S4126), where xPCol and yPCol are indexes indicating the position of the top left pixel of the coding block colCb in a picture ColPic at a different time.

On the other hand, a flag PredFlagL indicating whether LX prediction of the coding block colCb is used
If X[xPCol][yPCol] is 0 (step S4120: NO), the following process is performed. First, it is determined whether the POCs of all pictures registered in all reference lists are equal to or lower than the POC of the picture currently being processed (step S4128). It is also determined whether the flag PredFlagLY[xPCol][yPCol] indicating whether LY prediction of colCb is used is 1 (step S4128). Here, LY prediction is defined as a reference list different from LX prediction. That is, when LX=L0, LY=L1, and when LX=L1, LY=L0.

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

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

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

Next, the motion vector mvCol is scaled to obtain a motion vector mvLXCol (step S4138). This process is performed in step S424 in the temporal motion vector predictor candidate derivation unit 322.
5, so the explanation will be omitted.

Again, refer to Fig. 44. Once inter prediction information is derived for each reference list, the calculated motion vector mvLXCol is set as a central motion vector ctrMvLX, and the calculated flag predFlagLXCol is set as a flag ctrPredFlagLX (steps S4022 and S4023).

Then, it is determined whether the central motion vector is valid or invalid (step S4024).
If dFlagL0=0 and ctrPredFlagL1=0, it is determined to be invalid, otherwise it is determined to be invalid. If the central motion vector is invalid (step S4024: NO), a flag indicating the presence of a sub-block temporal merging candidate is set to availableFlagSbCol=0 (step S4003), and the process of the sub-block temporal merging candidate derivation unit is terminated.

On the other hand, if the central motion vector is valid (step S4024: YES), the flag indicating the presence of a sub-block temporal merge candidate is set to availableFlagSbCol=1 (step S402
5) Derive sub-block motion information (step S4026). This process will be described with reference to FIG.

First, the number of sub-blocks in the width direction is calculated from the width cbWidth and height cBheight of the coding block colCb.
Calculate numSbX and the number of sub-blocks in the height direction numSbY (step S4152). Also, set refIdxLXSbCol=0 (step S4152). After this process, the prediction sub-block c
Repeat the process in units of olSb. This repetition starts with the height index ySbIdx set to 0
The processing is performed while changing the width direction index xSbIdx from 0 to numSbX, and the width direction index xSbIdx from 0 to numSbY.

If the top left position of the coding block colCb is (xCb, yCb), the top left position of the prediction sub-block colSb is (xSb, ySb).
xSb = xCb + xSbIdx * sbWidth
ySb = yCb + ySbIdx * sbHeight
Next, the position obtained by adding the temporal motion vector tempMv to the prediction sub-block colSb is set as a new colSb (step S4154). The upper left position of the prediction sub-block colSb is (xColSb, yColSb), and the temporal motion vector tempMv is calculated with 1/16 pixel accuracy as (tempMv[0],
tempMv[1]), the top left position of the new colSb is
xColSb = Clip3( xCtb, xCtb + CtbSizeY + 3, xSb + ( tempMv[0] >> 4 ) )
yColSb = Clip3( yCtb, yCtb + CtbSizeY - 1, ySb + ( tempMv[1] >> 4 ) )
Here, the position of the top left corner of the tree block is (xCtb, yCtb), and the size of the tree block is CtbSizeY. As shown in the above formula, the position after adding tempMv is corrected to within the range of about the size of the tree block so that it does not deviate significantly from the position before adding tempMv. If this position is outside the screen, it is corrected to within the screen.

Then, inter prediction information is derived for each reference list (steps S4156 and S41
58). Here, for the prediction sub-block colSb, a motion vector mvLXSbCol for each reference list in sub-block units and a flag availableFl indicating whether the prediction sub-block is available or not are
Derive agLXSbCol. LX indicates the reference list. In the derivation of reference list 0, LX becomes L0.
In the derivation of the reference list 1, LX is L1. The derivation of the inter prediction information is performed in S4022 of FIG.
Since this is the same as S4023, the explanation will be omitted.

After deriving the inter prediction information (steps S4156 and S4158), the prediction sub-block col
It is determined whether Sb is valid (step S4160).
If bleFlagL1SbCol=0, colSb is invalid, otherwise it is determined that it is valid. If colSb is invalid (step S4160: NO), the motion vector mvLXSbCol is set as the central motion vector ctrMvLX (step S4162). Furthermore, a flag predFl indicating whether or not LX prediction is used is set.
agLXSbCol is set as the flag ctrPredFlagLX for the central motion vector (step S416
2) This completes the derivation of sub-block motion information.

Referring again to Figure 44, the L0 motion vector mvL0SbCol and the L1 motion vector mvL1SbCol are added as candidates to the subblock merge candidate list subblockMergeCandList in the subblock merge mode derivation unit 304 (step S4028).
However, this addition does not include the flag availableSbCol which indicates the presence of sub-block time merge candidates.
= 1. With the above, the process of the temporal merge candidate derivation unit 342 ends.

The above description of the sub-block temporal merging candidate derivation unit 381 is for encoding, but the same applies to decoding. That is, the operation of the sub-block temporal merging candidate derivation unit 481 in the sub-block merging mode derivation unit 404 in Fig. 22 can be similarly described by replacing encoding in the above description with decoding.

<Motion Compensation Prediction Processing>
The motion compensation prediction unit 306 acquires the position and size of a block currently being subjected to prediction processing in encoding. The motion compensation prediction unit 306 also acquires inter prediction information from the inter prediction mode determination unit 305. A reference index and a motion vector are derived from the acquired inter prediction information, and a reference picture specified by the reference index in the decoded image memory is acquired at a position where the reference picture is moved by the amount of the motion vector from the same position as the image signal of the prediction block, and then a prediction signal is generated.

In the case where the inter prediction mode in the inter prediction is prediction from a single reference picture such as L0 prediction or L1 prediction, the prediction signal obtained from one reference picture is used as a motion compensation prediction signal, and in the case where the inter prediction mode is prediction from two reference pictures such as BI prediction, the weighted average of the prediction signals obtained from the two reference pictures is used as a motion compensation prediction signal, and the motion compensation prediction signal is supplied to the prediction method determination unit. Here, the ratio of the weighted average of bi-prediction is set to 1:1, but the weighted average may be performed using another ratio.
For example, the weighting ratio may be increased as the picture interval between the picture to be predicted and the reference picture becomes closer. Also, the weighting ratio may be calculated using a correspondence table of combinations of picture intervals and weighting ratios.

The motion compensation prediction unit 406 has the same function as the motion compensation prediction unit 306 on the encoding side. The motion compensation prediction unit 406 outputs inter prediction information to the normal prediction motion vector mode derivation unit 401,
The mode is obtained from the normal merge mode derivation unit 402 , the sub-block predicted motion vector mode derivation unit 403 , and the sub-block merge mode derivation unit 404 via the switch 408 .

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

<Inter prediction mode>
A process of making a prediction from a single reference picture is defined as uni-prediction, and in the case of uni-prediction, prediction is made using either one of two reference pictures registered in the reference lists L0 and L1, called L0 prediction or L1 prediction. L0 prediction and L1 prediction may be forward prediction (prediction referring to a forward reference image) or backward prediction (prediction referring to a backward reference image). Figures 57 and 58 are diagrams for explaining motion compensation prediction in L0 prediction (uni-prediction).

FIG. 57 shows the inter prediction mode L0 prediction and the reference picture of L0 (RefL0Pi
c) is located before the picture to be processed (CurPic).
indicates a case where L0 prediction is performed and the L0 reference picture is at a later time than the current picture to be processed. Similarly, uni-prediction can be performed by replacing the reference picture for L0 prediction in Figures 57 and 58 with the reference picture for L1 prediction (RefL1Pic).

A process of making a prediction from two reference pictures is defined as bi-prediction, and in the case of bi-prediction, both L0 prediction and L1 prediction are used to express bi-prediction. Figures 59 to 61 are diagrams for explaining motion compensation prediction in bi-prediction. Figure 59 shows a case in which the reference picture of L0 prediction is at a time before the processing target picture and the reference picture of L1 prediction is at a time after the processing target picture in bi-prediction. Figure 60 shows a case in which the reference picture of L0 prediction and the reference picture of L1 prediction are at a time before the processing target picture in bi-prediction. Figure 61 shows a case in which the reference picture of L0 prediction and the reference picture of L1 prediction are at a time after the processing target picture in bi-prediction.

In this way, the relationship between the prediction type and time of L0/L1 can be used without being limited to L0 being forward prediction (prediction that refers to a forward reference image) and L1 being backward prediction (prediction that refers to a backward reference image). In the case of bi-prediction, the same reference picture may be used to perform both L0 prediction and L1 prediction. Note that the decision as to whether to perform motion compensation prediction in uni-prediction or bi-prediction is made based on information (e.g., a flag) indicating whether to use L0 prediction and whether to use L1 prediction.

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

<Motion compensation process based on normal predicted motion vector mode>
16 , when the inter prediction information by the normal prediction motion vector mode derivation unit 301 is selected in the inter prediction mode determination unit 305, the motion compensation prediction unit 306 acquires this inter prediction information from the inter prediction mode determination unit 305, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.

Similarly, the motion compensation prediction unit 406, as shown in the inter prediction unit 203 on the decoding side in FIG. 22, switches the normal prediction motion vector mode derivation unit 40
When the signal processing unit 205 is connected to the normal prediction motion vector mode derivation unit 401, the signal processing unit 205 obtains inter prediction information from the normal prediction motion vector mode derivation unit 401, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the decoded image signal superimposition unit 207.

<Motion compensation process based on normal merge mode>
As also shown in the inter prediction unit 102 on the encoding side in FIG. 16 , when the inter prediction mode determination unit 305 selects inter prediction information by the normal merge mode derivation unit 302, the motion compensation prediction unit 306 obtains this inter prediction information from the inter prediction mode determination unit 305 and determines the inter prediction mode of the block currently being processed,
The prediction method determination unit 105 derives a reference index and a motion vector to generate a motion compensation prediction signal.

22 , when a switch 408 is connected to the normal merge mode derivation unit 402 during the decoding process, the motion compensation prediction unit 406 obtains inter prediction information from the normal merge mode derivation unit 402, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the decoded image signal superimposition unit 207.

<Motion compensation process based on sub-block predicted motion vector mode>
16 , when inter prediction information is selected by the sub-block prediction motion vector mode derivation unit 303 in the inter prediction mode determination unit 305, the motion compensation prediction unit 306 acquires this inter prediction information from the inter prediction mode determination unit 305, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.

22, when a switch 408 is connected to the sub-block prediction motion vector mode derivation unit 403 during the decoding process, the motion compensation prediction unit 406 obtains inter prediction information from the sub-block prediction motion vector mode derivation unit 403, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the decoded image signal superimposition unit 207.

<Motion compensation process based on sub-block merge mode>
16 , when inter prediction information by the sub-block merge mode derivation unit 304 is selected in the inter prediction mode determination unit 305, the motion compensation prediction unit 306 acquires this inter prediction information from the inter prediction mode determination unit 305, derives the inter prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.

Similarly, the motion compensation prediction unit 406, as shown in the inter prediction unit 203 on the decoding side in FIG. 22, receives the sub-block merge mode derivation unit 404 when the switch 408 is turned on during the decoding process.
, the inter prediction information is obtained from the subblock merge mode derivation unit 404, the inter prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the decoded image signal superimposition unit 207.

<Affine Mode-Based Motion Compensation Processing>
In this embodiment, motion compensation based on an affine model can be used. In motion compensation based on an affine model, two to four corners of an encoding block are set as control points, motion vectors of sub-blocks are derived from motion vectors of the control points, and motion compensation is performed on a sub-block basis.

In the encoding process, the following flags are reflected based on the inter prediction conditions determined by the inter prediction mode determination unit 305, and are encoded in the encoded stream. In the decoding process, whether or not to perform motion compensation using an affine model is specified based on the following flags in the encoded stream.

sps_affine_enabled_flag indicates whether or not motion compensation based on an affine model can be used in inter prediction. If sps_affine_enabled_flag is 0, motion compensation based on an affine model is suppressed on a sequence-by-sequence basis.
The cu_affine_type_flag is not signaled in the CU (coding unit) syntax of the coded video sequence. If sps_affine_enabled_flag is 1, then affine model motion compensation is available in the coded video sequence.

sps_affine_type_flag indicates whether or not motion compensation using the six-parameter affine mode can be used in inter prediction. The six-parameter affine model is a mode in which a motion vector for a subblock is derived from six parameters of the horizontal and vertical components of each motion vector of three control points, and motion compensation is performed on a subblock basis. A motion vector is derived on a subblock basis, but a common reference index is derived on a coding block basis.

If sps_affine_type_flag is 0, motion compensation is suppressed from being based on a 6-parameter affine model.
Not conveyed in the syntax. If sps_affine_type_flag is set to 1, then motion compensation based on the six-parameter affine model is available for the coded video sequence.

If sps_affine_type_flag is not present, it is assumed to be 0.

When decoding a P or B slice, in the currently processed CU,
If r_affine_flag is 1, then affine model motion compensation is used to generate a motion compensated prediction signal for the currently targeted CU.

If inter_affine_flag is 0, no affine model is used for the currently targeted CU.

If inter_affine_flag is not present, it is assumed to be 0.

When decoding a P or B slice, in the currently processed CU,
If affine_type_flag is 1, motion compensation based on a six-parameter affine model is used to generate a motion compensated prediction signal for the currently targeted CU.

If cu_affine_type_flag is 0, motion compensation using a four-parameter affine model is used to generate a motion compensation prediction signal for the CU currently being processed. The four-parameter affine model is a mode in which a motion vector for a subblock is derived from four parameters, the horizontal and vertical components of each motion vector of two control points, and motion compensation is performed on a subblock-by-subblock basis.

<Merge Motion Vector Difference (MMVD)>
A differential motion vector can be added to the motion vectors of the top two merge candidates (merge candidates with merge indexes 0 and 1 in the merge candidate list), and this differential motion vector is called the merge differential motion vector.

When the merging motion vector difference is added in the merging candidate selection unit 347 on the encoding side,
The motion vector to which the merge differential motion vector is added is determined by the inter prediction mode determination unit 305.
to the motion compensation prediction unit 306 via the bitstream encoding unit 108. The bitstream encoding unit 108 also encodes information related to the merge differential motion vector. The information related to the merge differential motion vector is an index mmvd_distance_idx indicating the distance to be added to the motion vector, and an index mmvd_direction_idx indicating the direction in which the motion vector is added. These indexes are defined as shown in the tables in Figures 63(a) and 63(b). If the x and y components of the merge differential motion vector offset MmvdOffset are represented as MmvdOffset[0] and MmvdOffset[1], respectively, then
MmvdOffset[0] = ( MmvdDistance << 2 ) * MmvdSign[0]
MmvdOffset[1] = ( MmvdDistance << 2 ) * MmvdSign[1]
The merged motion vector difference is the merged motion vector offset MmvdOffs
The details of deriving the merged differential motion vector will be explained in the case of the decoding side below.

On the decoding side, when a merge differential motion vector exists, information on the merge differential motion vector is separated from the bit stream supplied to the bit string decoding unit 201, and a merge differential motion vector offset MmvdOffset is derived. In addition, the merge candidate selection unit 447 derives a merge differential motion vector from the decoded merge differential motion vector offset.
This merged motion vector difference is added to the motion vector, which is then provided to the motion compensation prediction unit 406 .

The derivation of the merge differential motion vector mMvdLX in the merge candidate selection unit 447 is shown in FIG.
First, it is determined whether the inter prediction mode of the coding block is bi-predictive (PRED_BI) (S4402).
If the prediction is L0 prediction (S4404: Yes), the process determines whether the prediction is L0 prediction (PRED_L0) (S4404: No).
mMvdL0 = MmvdOffset
mMvdL1 = 0
In the case of L1 prediction (S4404: No),
mMvdL0 = 0
mMvdL1 = MmvdOffset
This completes the process of deriving a merge differential motion vector (S4408).

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

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

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

As described above, MmvdDistance is defined as shown in the tables in Figures 63(a) and 63(c). Since these tables are defined with 1/4 pixel precision, the generated merge motion vector difference may include fractional pixel precision. However, by encoding/decoding a flag indicating that the pixel precision of these tables is 1 on a slice-by-slice basis, the generated merge motion vector difference can be changed so that it does not include fractional pixel precision.

Adaptive Motion Vector Resolution (AMVR)
The resolution of the differential motion vector can be adaptively changed for each coding block.
This resolution is called the adaptive motion vector resolution.

A case where adaptive motion vector resolution is used for normal prediction motion vector mode will be described. In this case, the motion vector of the derived candidate is rounded according to the resolution in the spatial prediction motion vector candidate derivation units 321 and 421, the temporal prediction motion vector candidate derivation units 322 and 422, and the history prediction motion vector candidate derivation units 323 and 423. The resolution can be selected from 1/4, 1, and 4 pixel accuracy, and when the resolution is not changed, the resolution is 1/4 pixel accuracy. The rounding process is performed according to the resolution of the motion vector in the coding block to be processed.
That is, the derived candidate motion vector mvX is
rightShift = leftShift = MvShift + 2
offset = 1 << ( rightShift - 1 )
mvX = ( mvX >= 0 ? ( mvX + offset ) >> rightShift :
- ( ( - mvX + offset ) >> rightShift ) ) << leftShift
Here, the resolution of the motion vector in the coding block to be processed is
In the case of 1/4 pixel accuracy, MvShift = 0. Similarly, when the resolution of the motion vector is 1 pixel accuracy, MvShift = 2, and when the resolution of the motion vector is 4 pixel accuracy, MvShift = 4. Each of the x and y components of mvX is processed by the above formula.

The adaptive motion vector resolution can also be used for the sub-block predicted motion vector mode. In this case, only the resolution is different from the above-mentioned normal predicted motion vector mode. That is, in the affine inherited predicted motion vector candidate derivation units 361 and 461, the affine constructed predicted motion vector candidate derivation units 362 and 462, and the affine identical predicted motion vector candidate derivation units 363 and 463, the derived candidate motion vectors are rounded according to the resolution. The resolution can be selected from 1/16, 1/4, or 1 pixel accuracy, and 1/4 is used when the resolution is not changed.
The accuracy is 16 pixels. The rounding process is performed according to the resolution of the motion vector in the coding block to be processed. In other words, the derived candidate motion vector mvX is rounded according to the above formula. Here, when the resolution of the motion vector in the coding block to be processed is 1/
In the case of four-pixel accuracy, MvShift = 0. Similarly, in the case of one-pixel accuracy, MvShift = 2. Each of the x and y components of mvX is processed by the above formula.

<Triangle merge mode>
The triangular merge mode is a type of merge mode, in which an encoding/decoding block is divided into diagonal partitions and motion compensation prediction is performed.

The triangular merge mode will be described with reference to Fig. 65. Fig. 65 shows the prediction of an encoding/decoding block in a 16x16 triangular merge mode. An encoding/decoding block in the triangular merge mode is divided into 4x4 subblocks, and each subblock is divided into a uni-predictive partition 0 (UNI0), a uni-predictive partition 1 (UNI1), a bi-predictive partition 2 (UNI2), and a bi-predictive partition 3 (UNI3).
In this example, the subblocks above the diagonal are assigned to partition 0, the subblocks below the diagonal are assigned to partition 1, and the subblocks on the diagonal are assigned to partition 2.
If plit_dir is 0, partitions are allocated as shown in FIG.
If iangle_split_dir is 1, partitions are allocated as shown in FIG.

For the motion compensation prediction of partition 0, uni-predictive motion information specified by merging triangle index 0 is used. For the motion compensation prediction of partition 1, uni-predictive motion information specified by merging triangle index 1 is used. For the motion compensation prediction of partition 2, uni-predictive motion information specified by merging triangle index 0 and merging triangle index 1 are used.
The bi-predictive motion information is used by combining the uni-predictive motion information specified by

Here, the uni-predictive motion information is a set of a motion vector and a reference index, and the bi-predictive motion information is composed of two sets of a motion vector and a reference index. Furthermore, the motion information refers to the uni-predictive motion information or the bi-predictive motion information.

The merge candidate selection units 347 and 447 select the derived merge candidate list, mergeCandList
is used as the triangle merge candidate list triangleMergeCandList.

The flowchart in Figure 66 for deriving triangle merge candidates is explained.

First, we create a triangle merge candidate list called mergeCandList.
The number of candidates in the triangle merge candidate list, numTriangleMerge, is used (step S3501).
Cand is set to the same value as the number of merge candidates, numCurrMergeCand.

Next, derive uni-prediction motion information for the merged triangular partition (step S3502).
.

FIG. 67 is a flowchart illustrating derivation of uni-prediction motion information of merged triangular partitions in this embodiment.

In this embodiment, uni-predictive motion information is derived in the same priority order for merging triangular partition 0 and merging triangular partition 1, thereby reducing the processing load.

First, for the Mth candidate in the derived merge candidate list, mergeCandList,
has motion information in the motion information list L0 (step S3601). If candidate M has motion information in the motion information list L0, the motion information in the motion information list L0 of candidate M is set as a triangle merge candidate (step S3602).

Next, for the Mth candidate in the derived merge candidate list mergeCandList, it is determined whether the candidate M has motion information in the motion information list L1 (step S3603). If the candidate M has motion information in the motion information list L1, the motion information in the motion information list L1 of the candidate M is set as a triangle merge candidate (step S3604).
, 1, 0), in descending order, step S3601, step S3602, step S36
03. Step S3604 is performed to additionally derive triangle merging candidates.

Figure 68 is a diagram illustrating an example of motion information for triangle merging candidates in this embodiment.

FIG. 68A shows an example of a merge candidate list. The merge candidate with merge index 0 has an inter prediction mode of bi-prediction (Pred-BI) and motion information of motion information list L0 is MV0
_L0, and the motion information of the motion information list L1 is MV0_L1. The merge candidate of merge index 1 has an inter prediction mode of uni-prediction (Pred-L0), the motion information of the motion information list L0 is MV1_L0, and the motion information of the motion information list L1 is not included. The merge candidate of merge index 2 has an inter prediction mode of uni-prediction (Pred-L1), has no motion information of the motion information list L0, and the motion information of the motion information list L1 is MV2_L1. The merge candidate of merge index 3 has an inter prediction mode of bi-prediction (Pred-BI), the motion information of the motion information list L0 is MV3_L0, and the motion information of the motion information list L1 is MV3_L1. The merge candidate of merge index 4 has an inter prediction mode of uni-prediction (Pred-L0), the motion information of the motion information list L0 is MV4_L0, and the motion information of the motion information list L1 is not included.

FIG. 68B is a diagram illustrating the relationship between the merging triangular index and the merging triangular partition for the example of the merging candidate list in FIG. 68A.

The uni-prediction motion information candidates for merge triangle partition 0 are MV0_L0, MV0_L1, MV1_L0, and MV2_
The motion information is composed in the order of L1, MV3_L0.

Similarly, the uni-prediction motion information candidates for merge triangle partition 1 are MV0_L0, MV0_L1, and MV1_L0.
The motion information is composed in the order of MV_L, MV2_L1, MV3_L0, (MV3_L1), but to ensure that the motion information of merge triangle partition 0 and the motion information of merge triangle partition 1 are not identical, the uni-predictive motion information selected by merge triangle index 0 (merge_triangle_idx0) is excluded to derive merge triangle index 1 (merge_triangle_idx1).

In this way, by setting the priorities of the uni-prediction motion information candidates for merging triangle partition 0 and merging triangle partition 1 to be the same as those in the merge list candidate list, an efficient triangle merge mode can be transmitted with a small amount of code. Also, by transmitting merging triangle index 0 and merging triangle index 1 so that the motion information of merging triangle partition 0 and the motion information of merging triangle partition 1 are not identical, redundancy in which the motion information of merging triangle partition 0, which does not need to be in triangle merge mode, is identical to the motion information of merging triangle partition 1 is eliminated, and the triangle merge mode can be transmitted with a small amount of code.

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

In order to exchange encoded bitstreams between an image encoding device and an image decoding device,
When a wired or wireless network is used, the coded bit stream may be converted into a data format suitable for the transmission mode of the communication channel before being transmitted. In this case, a transmitting device is provided that converts the coded bit stream output by the image coding device into coded data in a data format suitable for the transmission mode of the communication channel and transmits the coded data to the network, and a receiving device is provided that receives the coded data from the network, restores it to a coded bit stream, and supplies it to the image decoding device. The transmitting device includes a memory that buffers the coded bit stream output by the image coding device, and
The image decoding device includes a packet processing unit that packetizes the encoded bit stream and a transmitting unit that transmits the packetized encoded data via a network. The receiving device includes a receiving unit that receives the packetized encoded data via the network, a memory that buffers the received encoded data, and a packet processing unit that packetizes the encoded data to generate an encoded bit stream and provides the encoded bit stream to an image decoding device.

In order to exchange encoded bitstreams between an image encoding device and an image decoding device,
When a wired or wireless network is used, in addition to a transmitting device and a receiving device,
A relay device may be provided that receives the encoded data transmitted by the transmitting device and supplies it to the receiving device. The relay device includes a receiving unit that receives packetized encoded data transmitted by the transmitting device, a memory that buffers the received encoded data, and a transmitting unit that transmits the packetized encoded data to a network. The relay device may further include a receiving packet processing unit that processes the packetized encoded data to generate an encoded bit stream, a recording medium that accumulates the encoded bit stream, and a transmitting packet processing unit that packetizes the encoded bit stream.

Moreover, a display unit for displaying an image decoded by the image decoding device may be added to the configuration to form a display device. In this case, the display unit reads out the decoded image signal generated by the decoded image signal superimposition unit 207 and stored in the decoded image memory 208, and displays it on a screen.

Moreover, an imaging unit may be added to the configuration and the captured image may be input to the image coding device to form an imaging device. In this case, the imaging unit inputs a captured image signal to the block division unit 101.

The above-mentioned encoding and decoding processes may be realized not only as a transmission, storage, and receiving device using hardware, but also as firmware stored in a ROM (read-only memory) or flash memory, or as software for a computer, etc. The firmware program or software program may be provided by recording it on a recording medium readable by a computer, etc., or may be provided from a server via a wired or wireless network, or may be provided as a data broadcast of a terrestrial or satellite digital broadcast.

The present invention has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention.

100 Image encoding device, 101 Block division unit, 102 Inter prediction unit,
103 Intra prediction unit, 104 Decoded image memory, 105 Prediction method determination unit, 10
6 Residual signal generating unit, 107 Orthogonal transform and quantization unit, 108 Bit string encoding unit,
109 Inverse quantization and inverse orthogonal transformation unit, 110 Decoded image signal superimposition unit, 111 Encoded information storage memory, 200 Image decoding device, 201 Bit string decoding unit, 202 Block division unit, 203 Inter prediction unit, 204 Intra prediction unit, 205 Encoded information storage memory, 206 Inverse quantization and inverse orthogonal transformation unit, 207 Decoded image signal superimposition unit, 2
08 Decoded Image Memory.

Claims (8)

A video encoding device using a merge mode, comprising:
a merge candidate list builder for building a merge candidate list including spatial merge candidates;
A normal merge candidate selection unit that selects a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection unit that selects a first triangle merge candidate that is uni-predictive and a second triangle merge candidate that is uni-predictive from the merge candidate list;
an encoding unit that encodes a first index that identifies the first triangle merge candidate and a second index that identifies the second triangle merge candidate;
Equipped with
the triangle merge candidate selection unit derives the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index, and derives the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
the triangle merge candidate selection unit uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the candidates include L0 motion information, sets the L0 motion information as a triangle merge candidate, and then determines whether the candidates in the merge candidate list include L1 motion information, and if the candidates include L1 motion information, sets the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video encoding device comprising: 1. A video encoding method using a merge mode, comprising:
a merge candidate list construction step of constructing a merge candidate list including spatial merge candidates;
A normal merge candidate selection step of selecting a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection step of selecting a first triangle merge candidate that is uni-predictive and a second triangle merge candidate that is uni-predictive from the merge candidate list;
encoding a first index identifying the first triangle merge candidate and a second index identifying the second triangle merge candidate;
Equipped with
The triangle merge candidate selection step includes deriving the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index , and deriving the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
The triangle merge candidate selection step uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the L0 motion information is included, select the L0 motion information as a triangle merge candidate, and then determine whether the candidates in the merge candidate list include L1 motion information, and if the L1 motion information is included, select the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video encoding method comprising: A video encoding program using a merge mode, comprising:
a merge candidate list construction step of constructing a merge candidate list including spatial merge candidates;
A normal merge candidate selection step of selecting a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection step of selecting a first triangle merge candidate that is uni-predictive and a second triangle merge candidate that is uni-predictive from the merge candidate list;
an encoding step of encoding a first index identifying the first triangle merge candidate and a second index identifying the second triangle merge candidate;
Equipped with
The triangle merge candidate selection step includes deriving the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index , and deriving the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
The triangle merge candidate selection step uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the L0 motion information is included, select the L0 motion information as a triangle merge candidate, and then determine whether the candidates in the merge candidate list include L1 motion information, and if the L1 motion information is included, select the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video encoding program comprising: A video decoding device using a merge mode, comprising:
a decoder for decoding a first index identifying a first triangle merging candidate and a second index identifying a second triangle merging candidate;
a merge candidate list builder for building a merge candidate list including spatial merge candidates;
A normal merge candidate selection unit that selects a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection unit that selects the first triangle merge candidate that is uni -predictive and the second triangle merge candidate that is uni-predictive from the merge candidate list;
Equipped with
the triangle merge candidate selection unit derives the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index, and derives the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
the triangle merge candidate selection unit uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the candidates include L0 motion information, sets the L0 motion information as a triangle merge candidate, and then determines whether the candidates in the merge candidate list include L1 motion information, and if the candidates include L1 motion information, sets the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video decoding device comprising: A video decoding method using a merge mode, comprising the steps of:
a decoding step of decoding a first index identifying a first triangle merge candidate and a second index identifying a second triangle merge candidate;
a merge candidate list construction step of constructing a merge candidate list including spatial merge candidates;
A normal merge candidate selection step of selecting a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection step of selecting a first triangle merge candidate that is uni-predictive and a second triangle merge candidate that is uni-predictive from the merge candidate list;
Equipped with
The triangle merge candidate selection step includes deriving the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index , and deriving the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
The triangle merge candidate selection step uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the L0 motion information is included, select the L0 motion information as a triangle merge candidate, and then determine whether the candidates in the merge candidate list include L1 motion information, and if the L1 motion information is included, select the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video decoding method comprising: A video decoding program using a merge mode, comprising:
a decoding step of decoding a first index identifying a first triangle merge candidate and a second index identifying a second triangle merge candidate;
a merge candidate list construction step of constructing a merge candidate list including spatial merge candidates;
A normal merge candidate selection step of selecting a normal merge candidate that is uni-predictive or bi-predictive from the merge candidate list;
a triangle merge candidate selection step of selecting a first triangle merge candidate that is uni-predictive and a second triangle merge candidate that is uni-predictive from the merge candidate list;
Equipped with
The triangle merge candidate selection step includes deriving the first triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the first index , and deriving the second triangle merge candidate from the merge candidate list including bi-predictive merge candidates using the second index ;
The triangle merge candidate selection step uses the first index and the second index to first determine whether the candidates in the merge candidate list include L0 motion information, and if the L0 motion information is included, select the L0 motion information as a triangle merge candidate, and then determine whether the candidates in the merge candidate list include L1 motion information, and if the L1 motion information is included, select the L1 motion information as a triangle merge candidate, thereby selecting the first triangle merge candidate and the second triangle merge candidate.
A video decoding program comprising: A method for storing a bitstream generated by the video encoding method according to claim 2 on a recording medium. A transmission method for transmitting a bitstream generated by the video encoding method according to claim 2.

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