Image encoding device, image encoding method, image encoding program, image decoding device, image decoding method, and image decoding program

Abstract

To provide a technology for improving encoding efficiency by performing block division suitable for encoding and decoding an image.SOLUTION: There is provided a technology for improving encoding efficiency by performing block division suitable for encoding and decoding an image. Included are an encoded information storage unit that adds inter-prediction information used for inter-prediction to a history predictive motion vector candidate list; a history predictive motion vector candidate derivation unit that derives history predictive motion vector candidates from the history predictive motion vector candidate list; and a history merge candidate derivation unit that derives history merge candidates from the history predictive motion vector candidate list. The history predictive motion vector candidate derivation unit and the history merge candidate derivation unit refer to the candidates included in the history predictive motion vector candidate list in orders different from each other, and designate each of the candidates as a history predictive motion vector candidate or a history merge candidate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image encoding and decoding technique that divides an image into blocks and performs prediction. [Background technology]

[0002] In image encoding and decoding, the image to be processed is divided into blocks, which are groups of a predetermined number of pixels. Divide into appropriate blocks and process in blocks. Encoding efficiency is improved by appropriately setting inter-frame prediction and frame prediction. do.

[0003] In video coding and decoding, inter-prediction is used, which predicts from pictures that have already been coded or decoded. In Patent Document 1, affine transformation is used in inter-prediction. The technology to be applied is described. In moving images, objects undergo transformations such as enlargement, reduction, and rotation. It is not uncommon for this to happen, and by applying the technology of Patent Document 1, efficient coding This becomes possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-172644 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 involves image conversion, which places a heavy processing load on the system. In view of the above-mentioned problems, the present invention provides a low-load, efficient encoding technique. . [Means for solving the problem]

[0006] In order to solve the above problems, an image coding apparatus according to a first aspect of the present invention includes: a coding information storage unit that adds inter prediction information used in inter prediction to a list of motion vector history candidates; a spatial motion vector history candidate derivation unit that derives spatial motion vector history candidates from blocks adjacent to a current block to be processed and adds the spatial motion vector history candidates to the motion vector history candidate list; a temporal motion vector history candidate derivation unit that derives temporal motion vector history candidates from blocks located at the same position as the current block to be processed or nearby and adds the temporal motion vector history candidates to the motion vector history candidate list; a motion vector history candidate derivation unit that derives spatial merge candidates from blocks adjacent to the current block to be processed and adds the spatial merge candidates to a merge candidate list; a history merge candidate derivation unit that derives a history merge candidate from the history predicted motion vector candidate list and adds the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation unit that derives an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adds the average merge candidate to the merge candidate list; a predictor motion vector candidate selection unit that selects a predictor motion vector to be used for inter prediction from the predictor motion vector candidate list and determines a predictor motion vector index indicating the predictor motion vector; a merge candidate selection unit that selects a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determines a merge index indicating the merge candidate; and an encoding unit that encodes the predictor motion vector index or the merge index, wherein the history predicted motion vector candidate derivation unit refers to candidates included in the history predicted motion vector candidate list in order from oldest to newest, and the history merge candidate derivation unitThe candidates included in the history motion vector predictor candidate list are referenced in order from newest to oldest.

[0007] An image coding method of a second aspect of the present invention includes a coding information storing step of adding inter prediction information used in inter prediction to a motion vector history candidate list; a spatial motion vector candidate derivation step of deriving a spatial motion vector candidate from a block adjacent to a current block to be processed and adding the spatial motion vector candidate to the motion vector candidate list; a temporal motion vector candidate derivation step of deriving a temporal motion vector candidate from a block located at the same position as the current block to be processed or nearby and adding the temporal motion vector candidate to the motion vector candidate list; a motion vector candidate history derivation step of deriving a spatial merge candidate from the block adjacent to the current block to be processed and adding the spatial merge candidate to a merge candidate list; and a spatial merge candidate derivation step of deriving a temporal merge candidate from a block located at the same position as the current block to be processed or nearby and adding the temporal merge candidate to the merge candidate list. a history merge candidate derivation step of deriving a history merge candidate from the history motion vector candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a predictor motion vector candidate selection step of selecting a predictor motion vector to be used for inter prediction from the predictor motion vector candidate list and determining a predictor motion vector index indicating the predictor motion vector; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determining a merge index indicating the merge candidate; and an encoding step of encoding the predictor motion vector index or the merge index, wherein the history predictor motion vector candidate derivation step refers to candidates included in the history predictor motion vector candidate list in order from the oldest to the newest candidates, and the history merge candidate derivation stepThe candidates included in the history motion vector predictor candidate list are referenced in order from newest to oldest.

[0008] An image coding program according to a third aspect of the present invention includes a coding information storing step of adding inter prediction information used in inter prediction to a motion vector history candidate list; a spatial motion vector candidate derivation step of deriving a spatial motion vector candidate from a block adjacent to a current block to be processed and adding the spatial motion vector candidate to the motion vector candidate predictor list; a temporal motion vector candidate derivation step of deriving a temporal motion vector candidate from a block located at the same position as the current block to be processed or nearby and adding the temporal motion vector candidate to the motion vector candidate predictor list; a motion vector candidate history derivation step of deriving a spatial merge candidate from the block adjacent to the current block to be processed and adding the spatial merge candidate to a merge candidate list; and a spatial merge candidate derivation step of deriving a temporal merge candidate from a block located at the same position as the current block to be processed or nearby and adding the temporal merge candidate to the merge candidate list. a history merge candidate derivation step of deriving a history merge candidate from the history predicted motion vector candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a predictor motion vector candidate selection step of selecting a predictor motion vector to be used for inter prediction from the predictor motion vector candidate list and determining a predictor motion vector index indicating the predictor motion vector; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determining a merge index indicating the merge candidate; and an encoding step of encoding the predictor motion vector index or the merge index, wherein the history predicted motion vector candidate derivation step refers to candidates included in the history predicted motion vector candidate list in order from the oldest to the newest candidates, and the history merge candidate derivation stepThe candidates included in the history motion vector predictor candidate list are referenced in order from newest to oldest.

[0009] an image decoding device according to a fourth aspect of the present invention, comprising: an encoding information storage unit that adds inter prediction information used in inter prediction to a history motion vector candidate list; a decoding unit that decodes a predicted motion vector index or a merge index; a spatial predicted motion vector candidate derivation unit that derives a spatial predicted motion vector candidate from a block adjacent to a current block and adds the spatial predicted motion vector candidate to the history motion vector candidate list; a temporal predicted motion vector candidate derivation unit that derives a temporal predicted motion vector candidate from a block located at the same position as the current block or in a vicinity thereof and adds the temporal predicted motion vector candidate to the history motion vector candidate list; a history predicted motion vector candidate derivation unit that derives a history predicted motion vector candidate from the history motion vector candidate list and adds the history predicted motion vector candidate to the history motion vector candidate list; a spatial merge candidate derivation unit that derives a spatial merge candidate from a block adjacent to the current block and adds the spatial merge candidate to the merge candidate list; a temporal merge candidate derivation unit that derives a temporal merge candidate from a block located at the same position as or near a block, and adds the temporal merge candidate to the merge candidate list; a history merge candidate derivation unit that derives a history merge candidate from the history predicted motion vector candidate list, and adds the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation unit that derives an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list, and adds the average merge candidate to the merge candidate list; a predicted motion vector candidate selection unit that selects a predicted motion vector to be used for inter prediction from the predicted motion vector candidate list based on the predicted motion vector index; and a merge candidate selection unit that selects a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index, wherein the history predicted motion vector candidate derivation unit refers to the candidates included in the history predicted motion vector candidate list in order from the oldest to the newest, The history merge candidate derivation unit refers to the history motion vector predictor candidate list in order from newest to oldest candidates.

[0010] An image decoding method according to a fifth aspect of the present invention is an image decoding method for decoding a bit string obtained by encoding a video using inter prediction based on inter prediction information in units of blocks obtained by dividing each picture of the video, the image decoding method including: a coding information storing step of adding inter prediction information used in the inter prediction to a history prediction motion vector candidate list; a decoding step of decoding a predicted motion vector index or a merge index; a spatial prediction motion vector candidate derivation step of deriving a spatial prediction motion vector candidate from a block adjacent to a current block to be processed and adding the spatial prediction motion vector candidate to the prediction motion vector candidate list; a temporal prediction motion vector candidate derivation step of deriving a temporal prediction motion vector candidate from a block located at the same position as the current block to be processed or in its vicinity and adding the temporal prediction motion vector candidate to the prediction motion vector candidate list; a history prediction motion vector candidate derivation step of deriving a history prediction motion vector candidate from the history prediction motion vector candidate list and adding the history prediction motion vector candidate to the prediction motion vector candidate list; a spatial merge candidate derivation step of deriving a spatial merge candidate and adding the spatial merge candidate to a merge candidate list; a temporal merge candidate derivation step of deriving a temporal merge candidate from a block located at the same position as the current block or in a vicinity thereof and adding the temporal merge candidate to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history predicted motion vector candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a predictor motion vector candidate selection step of selecting a predictor motion vector to be used for inter prediction from the predictor motion vector candidate list based on the predictor motion vector index; and a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index, wherein the history predicted motion vector candidate derivation stepThe motion vector predictor candidate list is referenced in order from the oldest candidate to the newest candidate, and the history merge candidate derivation step references the motion vector predictor candidate list in order from the newest candidate to the oldest candidate.

[0011] An image decoding program according to a sixth aspect of the present invention includes a coding information storing step of adding inter prediction information used in inter prediction to a history prediction motion vector candidate list; a decoding step of decoding a prediction motion vector index or a merge index; a spatial prediction motion vector candidate derivation step of deriving a spatial prediction motion vector candidate from a block adjacent to a current block to be processed and adding the spatial prediction motion vector candidate to the prediction motion vector candidate list; a temporal prediction motion vector candidate derivation step of deriving a temporal prediction motion vector candidate from a block located at the same position as the current block to be processed or in its vicinity and adding the temporal prediction motion vector candidate to the prediction motion vector candidate list; a history prediction motion vector candidate derivation step of deriving a history prediction motion vector candidate from the history prediction motion vector candidate list and adding the history prediction motion vector candidate to the prediction motion vector candidate list; a spatial merge candidate derivation step of deriving a spatial merge candidate from a block adjacent to the current block to be processed and adding the spatial merge candidate to the merge candidate list; a temporal merge candidate derivation step of deriving a temporal merge candidate from a block located at or near the position of a given block and adding the temporal merge candidate to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history predicted motion vector candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a predictor motion vector candidate selection step of selecting a predictor motion vector to be used for inter prediction from the predictor motion vector candidate list based on the predictor motion vector index; and a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index, wherein the history predicted motion vector candidate derivation step refers to candidates included in the history predicted motion vector candidate list in order from oldest to newest, and the history merge candidate derivation stepThe candidates included in the history motion vector predictor candidate list are referenced in order from newest to oldest. [Effects of the Invention]

[0012] According to the present invention, highly efficient image encoding and decoding processing can be realized with a low load. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram of an image encoding device according to an embodiment of the present invention; [Figure 2] 1 is a block diagram of an image decoding device according to an embodiment of the present invention. [Figure 3] 10 is a flowchart illustrating an operation of dividing a tree block. [Figure 4] FIG. 10 is a diagram illustrating how an input image is divided into tree blocks. [Figure 5] FIG. 1 is a diagram illustrating a z-scan. [Figure 6A] FIG. 10 is a diagram showing the divided shapes of blocks. [Figure 6B] FIG. 10 is a diagram showing the divided shapes of blocks. [Figure 6C] FIG. 10 is a diagram showing the divided shapes of blocks. [Figure 6D] FIG. 10 is a diagram showing the divided shapes of blocks. [Figure 6E] FIG. 10 is a diagram showing the divided shapes of blocks. [Figure 7] 10 is a flowchart illustrating an operation of dividing a block into four parts. [Figure 8] 10 is a flowchart illustrating an operation of dividing a block into two or three parts. [Figure 9] This is a syntax for expressing the shape of block division. [Figure 10A] FIG. 10 is a diagram illustrating intra prediction. [Figure 10B] FIG. 10 is a diagram illustrating intra prediction. [Figure 11]FIG. 10 is a diagram illustrating a reference block for inter prediction. [Figure 12] This is a syntax for expressing a coding block prediction mode. [Figure 13] FIG. 10 is a diagram showing correspondence between syntax elements and modes related to inter prediction. [Figure 14] FIG. 10 is a diagram for explaining affine transformation motion compensation of two control points. [Figure 15] FIG. 10 is a diagram for explaining affine transformation motion compensation of three control points. [Figure 16] FIG. 2 is a block diagram showing a detailed configuration of the inter prediction unit 102 in FIG. [Figure 17] FIG. 17 is a block diagram showing a detailed configuration of a normal predicted motion vector mode derivation unit 301 in FIG. [Figure 18] FIG. 17 is a block diagram showing a detailed configuration of a normal merge mode derivation unit 302 in FIG. 16. [Figure 19] 17 is a flowchart for explaining a normal predicted motion vector mode derivation process of the normal predicted motion vector mode derivation unit 301 of FIG. 16. [Figure 20] 10 is a flowchart showing a processing procedure of a normal predicted motion vector mode derivation process. [Figure 21] 10 is a flowchart illustrating a processing procedure for normal merge mode derivation processing. [Figure 22] FIG. 3 is a block diagram showing a detailed configuration of an inter prediction unit 203 in FIG. 2. [Figure 23] FIG. 23 is a block diagram showing a detailed configuration of a normal predicted motion vector mode derivation unit 401 in FIG. 22. [Figure 24] FIG. 23 is a block diagram showing a detailed configuration of a normal merge mode derivation unit 402 in FIG. 22. [Figure 25] 23 is a flowchart for explaining a normal predicted motion vector mode derivation process of the normal predicted motion vector mode derivation unit 401 of FIG. 22. [Figure 26] FIG. 10 is a diagram illustrating a procedure for initializing and updating a history motion vector predictor candidate list. [Figure 27]10 is a flowchart of a procedure for checking identical elements in the procedure for initializing and updating a history motion vector predictor candidate list. [Figure 28] 10 is a flowchart of an element shifting process procedure in the history motion vector predictor candidate list initialization / update process procedure. [Figure 29] 10 is a flowchart illustrating a procedure for deriving a historical motion vector predictor candidate. [Figure 30] 10 is a flowchart illustrating a history merge candidate derivation process procedure. [Figure 31A] FIG. 10 is a diagram illustrating an example of a history motion vector predictor candidate list update process. [Figure 31B] FIG. 10 is a diagram illustrating an example of a history motion vector predictor candidate list update process. [Figure 31C] FIG. 10 is a diagram illustrating an example of a history motion vector predictor candidate list update process. [Figure 32] FIG. 10 is a diagram illustrating motion compensation prediction in the case of L0 prediction in which the L0 reference picture (RefL0Pic) is located at a time earlier than the current picture (CurPic). [Figure 33] FIG. 10 is a diagram illustrating motion compensation prediction in the case where L0 prediction is performed and the reference picture for L0 prediction is located at a later time than the current picture. [Figure 34] FIG. 10 is a diagram illustrating the prediction direction of motion compensation prediction in bi-prediction, where the reference picture for L0 prediction is located at a time earlier than the current picture to be processed, and the reference picture for L1 prediction is located at a time later than the current picture to be processed. [Figure 35] FIG. 10 is a diagram illustrating the prediction direction of motion compensation prediction in bi-prediction when the reference picture for L0 prediction and the reference picture for L1 prediction are located at a time earlier than the current picture. [Figure 36] FIG. 10 is a diagram illustrating the prediction direction of motion compensation prediction in bi-prediction when the reference picture for L0 prediction and the reference picture for L1 prediction are located at a time later than the current picture. [Figure 37]1 is a diagram illustrating an example of a hardware configuration of a coding / decoding device according to an embodiment of the present invention; [Figure 38] 10 is a table showing another example of historical motion vector predictor candidates added by initializing the historical motion vector predictor candidate list. [Figure 39] 10 is a table showing another example of historical motion vector predictor candidates added by initializing the historical motion vector predictor candidate list. [Figure 40] 10 is a table showing another example of historical motion vector predictor candidates added by initializing the historical motion vector predictor candidate list. [Figure 41] FIG. 10 is a diagram illustrating the configuration of a history motion vector predictor candidate list. [Figure 42] FIG. 10 is a diagram for explaining how the top element is deleted when adding to a history motion vector predictor candidate list. [Figure 43] FIG. 10 is a diagram for explaining how elements are shifted within a list when adding to a history motion vector predictor candidate list. [Figure 44] FIG. 10 is a diagram for explaining how a new element is added to a historical motion vector predictor candidate list. [Figure 45] FIG. 11 is a diagram illustrating the order in which a historical motion vector predictor candidate list is referred to in the normal merge mode according to the second embodiment. [Figure 46] FIG. 11 is a diagram illustrating the order in which a historical motion vector predictor candidate list is referred to in a normal motion vector predictor mode according to the second embodiment. [Figure 47] 10 is a flowchart illustrating a procedure for deriving a historical motion vector predictor candidate according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] The technologies and technical terms used in this embodiment will be defined below.

[0015] <Tree Block> In this embodiment, the image to be encoded / decoded is divided equally into a predetermined size. In Figure 4, the size of the treeblock is 128x128 pixels. However, the size of the tree block is not limited to this and can be any size. The processing target (the encoding target in the encoding process, the decoding target in the decoding process) may be set. The tree blocks of the tree are arranged in raster scan order, i.e., from left to right and from top to bottom. The order is as follows: Inside each tree block, further recursive division is possible. After recursively dividing the tree block, the block to be coded and decoded is called the coding block. In addition, tree blocks and coding blocks are collectively defined as blocks. By dividing the blocks appropriately, efficient coding becomes possible. The size of the code can be a fixed value previously agreed upon between the coding device and the decoding device, or The size of the treeblock determined by the encoding device may be transmitted to the decoding device. Here, the maximum size of the treeblock is set to 128x128 pixels, and the treeblock size is set to The minimum size of the coding block is 16x16 pixels. The maximum size of the coding block is 64x64. The minimum size of a pixel,coding block is set to 4x4 pixels.

[0016] <Prediction mode> In the coding block unit, prediction is performed from the processed image signal of the image to be processed. Intra prediction (MODE_INTRA), and inter prediction (MO) that predicts from the image signal of the processed image. DE_INTER).

[0017] In the encoding process, a processed image is an image obtained by decoded a signal that has been encoded. It is used for codes, tree blocks, blocks, coding blocks, etc., and in the decoding process, is used for completed images, image signals, tree blocks, blocks, coding blocks, etc. .

[0018] This mode distinguishes between intra prediction (MODE_INTRA) and inter prediction (MODE_INTER). The prediction mode (PredMode) is defined as intra prediction (MODE_INTRA ), or inter prediction (MODE_INTER) as a value.

[0019] <Inter prediction> Inter-prediction, which predicts from the image signal of a processed image, refers to multiple processed images. It can be used as a picture. To manage multiple reference pictures, L0 (reference link) Two types of reference lists are defined: L1 (reference list 1) and L2 (reference list 2), and each has a reference index. P slices can use L0 prediction (Pred_L0) For B slices, L0 prediction (Pred_L0), L1 prediction (Pred_L1), and bi-prediction (Pred_BI) are available. ) is available. L0 prediction (Pred_L0) refers to the reference picture managed by L0. Inter prediction is performed using the reference picture managed by L1, and L1 prediction (Pred_L1) is performed using the reference picture managed by L1. Bi-prediction (Pred_BI) is inter-prediction where both L0 and L1 predictions are performed. Inter prediction refers to one reference picture managed in L0 and one in L1. Information specifying L0 prediction, L1 prediction, or bi-prediction is defined as an inter prediction mode. In the following processing, the constants and variables with the subscript LX in the output are L0, L1 It is assumed that processing is performed for each

[0020] <Predictive motion vector mode> The predicted motion vector mode is an index for specifying the predicted motion vector, a differential motion vector, and a The inter prediction vector, inter prediction mode, and reference index are transmitted, and the index of the block to be processed is This is a mode for determining the motion vector prediction information of the target block. A processed block or a block in the processed image that is at the same position as the target block A motion vector predictor candidate derived from a block located at or near (neighboring) the predicted motion vector candidate is used. The measured motion vector is derived from an index for identifying the measured motion vector.

[0021] <Merge mode> In merge mode, the target block is processed without transmitting differential motion vectors and reference indices. The processed blocks adjacent to the block to be processed or the blocks belonging to the processed image The inter prediction information of the block located at the same position as the block or in the vicinity (neighborhood) is used for processing. This is a mode for deriving inter prediction information for the current block.

[0022] The processed blocks adjacent to the target block and the inter-processing blocks The spatial merge candidate is defined as a block belonging to the processed image. Blocks located in the same location as the block or in its vicinity (neighborhood), and the index of that block Inter-prediction information derived from super-prediction information is defined as a temporal merge candidate. The complement is registered in the merge candidate list, and the prediction of the target block is determined by the merge index. Identify merge candidates to use in

[0023] <Adjacent Block> FIG. 11 shows the procedure for deriving inter prediction information in the predicted motion vector mode and merge mode. A0, A1, A2, B0, B1, B2, B3 is a processed block adjacent to the target block. T0 is a processed image. The block belongs to the same position as the processing target block in the processing target image or its vicinity ( It is a block located in the vicinity.

[0024] A1 and A2 are located on the left side of the coding block to be processed and are adjacent to the coding block to be processed. B1 and B3 are adjacent blocks located above the coding block to be processed. A0, B0, and B2 are the blocks adjacent to the target coding block. These are the blocks located at the bottom left, top right, and top left of the encryption block.

[0025] Details of how adjacent blocks are handled in predicted motion vector mode and merge mode The details will be described later.

[0026] <Affine transformation motion compensation> Affine transformation motion compensation divides a coding block into sub-blocks of a predetermined unit, and A motion vector is determined for each sub-block individually and motion compensation is performed. The motion vector of each sub-block is determined by the motion vector of the processed block adjacent to the current block, or is a block belonging to the processed image, which is at the same position as the target block or in its vicinity (neighborhood) based on one or more control points derived from inter prediction information of the block located at In this embodiment, the size of the sub-block is set to 4x4 pixels. The size is not limited to this, and the motion vector may be derived in units of pixels.

[0027] FIG. 14 shows an example of affine transformation motion compensation when there are two control points. A control point has two parameters, a horizontal component and a vertical component. The affine transformation in these two cases is called a four-parameter affine transformation. CP2 is the control point.

[0028] FIG. 15 shows an example of affine transformation motion compensation when there are three control points. A control point has two parameters, a horizontal component and a vertical component. The affine transformation in the three cases is called a six-parameter affine transformation. CP2 and CP3 are control points.

[0029] Affine transformation motion compensation is available in both the predicted motion vector mode and the merge mode. It is also available in the prediction motion vector mode. The mode in which the affine transformation is performed is defined as the sub-block predicted motion vector mode, and the merge mode is defined as the affine transformation mode. A mode in which motion compensation is applied is defined as a sub-block merge mode.

[0030] <Inter prediction syntax> The syntax related to inter prediction will be described with reference to FIGS.

[0031] The merge_flag in FIG. 12 indicates whether the current coding block is in merge mode or whether the predicted motion vector is merge_affine_flag is a flag that indicates whether to use the merge mode. This is a flag indicating whether or not to apply the sub-block merging mode to the current coding block. inter_affine_flag is the sub-block of the coding block to be processed in the predicted motion vector mode. cu_affine_type_flag A flag indicating whether to apply the affine motion vector prediction mode. is a flag for determining the number of control points in the sub-block predicted motion vector mode. is.

[0032] Figure 13 shows the values ​​of each syntax element and the corresponding prediction method. ag=1,merge_affine_flag=0 corresponds to the normal merge mode. merge_flag=1,merge_affine_flag=1 is a merge mode that is not a subblock merge. merge_flag=0,inter_affine_flag=0 corresponds to the normal prediction mode. Normal predicted motion vector mode corresponds to the sub-block predicted motion vector mode. merge_flag=0,inter_affine_flag=1 corresponds to the sub-block predicted motion vector mode. merge_flag=0,inter_affine_flag If cu_affine_type_flag is set to 1, the number of control points is determined.

[0033] <poc> POC (Picture Order Count) is a variable associated with the picture being coded. The value increases by one depending on the picture output order. It can determine whether a picture is the same as another picture, determine the order of pictures in the output order, and For example, if two pictures have the same POC, we can calculate the distance between them. If two pictures have different POC values, they are considered to be the same picture. If it does, the picture with the smaller POC value is determined to be the picture to be output first. The difference between the POCs of two pictures indicates the distance between the pictures along the time axis. (First embodiment) Regarding the image encoding device 100 and the image decoding device 200 according to the first embodiment of the present invention, I will explain.

[0034] FIG. 1 is a block diagram of an image coding device 100 according to a first embodiment. The image encoding device 100 includes a block division unit 101, an inter prediction unit 102, an intra prediction unit 103, and a A prediction unit 103, a decoded image memory 104, a prediction method determination unit 105, a residual generation unit 106, and an orthogonal A transform / quantization unit 107, a bit string encoding unit 108, an inverse quantization / inverse orthogonal transformation unit 109, and a decoding unit The image signal superimposing unit 110 and the coded information storage memory 111 are provided.

[0035] The block division unit 101 recursively divides the input image to generate coding blocks. The block division unit 101 divides the blocks to be divided into horizontal and vertical blocks. The four quadrants and the blocks to be divided can be arranged either horizontally or vertically. The block division unit 101 processes the generated coded blocks. The image signal of the processing target coding block is input to the inter prediction unit. 102, the intra prediction unit 103, and the residual generation unit 106. The unit 101 supplies information indicating the determined recursive division structure to the bit string encoding unit 108. The detailed operation of the lock dividing unit 101 will be described later.

[0036] The inter prediction unit 102 performs inter prediction on the coding block to be processed. The measurement unit 102 receives the inter-prediction information stored in the coded information storage memory 111 and the decoding information. A plurality of inter prediction information is calculated from the decoded image signal stored in the image memory 104. and deriving candidates for the inter prediction mode, selecting a suitable inter prediction mode from the derived candidates. and a predicted image signal according to the selected inter prediction mode. The inter prediction unit 102 supplies the data to the prediction method determination unit 105. The detailed configuration and operation of the inter prediction unit 102 will be described later. .

[0037] The intra prediction unit 103 performs intra prediction on the coding block to be processed. The measurement unit 103 measures the decoded image signal stored in the decoded image memory 104 as a reference pixel. and refers to the coding information stored in the coding information storage memory 111. A predicted image signal is generated by intra prediction based on the encoding information. The intra prediction unit 103 selects an appropriate intra prediction mode from among a plurality of intra prediction modes. Then, the selected intra prediction mode and a predicted image according to the selected intra prediction mode are generated. The image signal is supplied to a prediction method determination unit 105 .

[0038] 10A and 10B show examples of intra prediction. For example, the intra prediction mode 5 0 generates an intra-predicted image by copying reference pixels vertically. Prediction mode 1 is a DC mode in which all pixel values ​​of the block to be processed are converted to the reference pixel values. Intra prediction mode 0 is a planar mode, and vertical This mode creates a two-dimensional intra-prediction image from reference pixels in the vertical and horizontal directions. FIG. 10B shows an example of generating an intra-prediction image in the case of intra-prediction mode 40. The intra prediction unit 103 performs intra prediction on each pixel of the block to be processed in a manner indicated by the intra prediction mode. The intra prediction unit 103 copies the values ​​of the reference pixels in the intra prediction mode. If the pixel is not an integer position, the reference pixel value is interpolated from the reference pixel values ​​of the surrounding integer positions. Make a decision.

[0039] The decoded image memory 104 stores the decoded image generated by the decoded image signal superimposing unit 110 . The decoded image memory 104 transfers the stored decoded images to the inter prediction unit 102 and the intra prediction unit 103. The measurement unit 103 supplies the data.

[0040] The prediction method determination unit 105 determines the coding information for each of intra prediction and inter prediction. The evaluation is based on the amount of coding of the information and residual, the amount of distortion between the predicted image signal and the image signal to be processed, etc. In the case of intra prediction, the prediction method determination unit 10 5 is a bitstream encoding unit 1 which encodes intra prediction information such as an intra prediction mode as encoding information. In the case of the merge mode of inter prediction, the prediction method determination unit 105 supplies the merged sub-block merge mode (sub-block merge flag) The inter prediction information such as the inter frame coding information is supplied to the bitstream coding unit 108 as coding information. In the case of the predicted motion vector mode of the inter prediction, the prediction method determination unit 105 code, predicted motion vector index, L0, L1 reference index, differential motion vector information indicating whether it is a sub-block predicted motion vector mode (sub-block predicted motion vector) Inter prediction information such as a bit flag is supplied to the bitstream encoding unit 108 as encoding information. Furthermore, the prediction method determination unit 105 stores the determined coding information in the coding information storage memory 11. The prediction method determination unit 105 outputs the residual signal to the residual generation unit 106 and the prediction image signal to the decoded image 1. The signal is supplied to the signal superimposing unit 110.

[0041] The residual generation unit 106 generates a residual by subtracting a predicted image signal from an image signal to be processed. The generated signal is supplied to the orthogonal transform and quantization unit 107 .

[0042] The orthogonal transform and quantization unit 107 performs orthogonal transform and quantization on the residual in accordance with the quantization parameter. The generated residual is then input to a bitstream coding unit 10. 8 and the inverse quantization and inverse orthogonal transformation unit 109.

[0043] The bitstream coding unit 108 encodes the bitstream in units of sequences, pictures, slices, and coding blocks. In addition to the information, the prediction method determined by the prediction method determination unit 105 for each coding block is Specifically, the bit string coding unit 108 encodes the coding information according to the coding block. If the prediction mode is inter prediction (MODE_INTER), In this case, the bitstream encoding unit 108 sets a flag for determining whether or not the merge mode is selected, a sub-block merge merge flag, merge index if in merge mode, index if not in merge mode Sub-prediction mode, predicted motion vector index, information about differential motion vector, Encoding information (inter prediction information) such as block prediction motion vector flags is stored in the specified syntax. The first bitstream is generated by encoding it according to the bitstream syntax rules. If MODE_INTRA is intra prediction, coding information such as intra prediction mode (intra prediction The first bit is encoded according to a specified syntax (syntax rules for bit strings). The bit string coding unit 108 also generates a bit string by defining the orthogonally transformed and quantized residuals. The second bit string is generated by entropy encoding the bit string according to the syntax The encoding unit 108 multiplexes the first bit string and the second bit string according to a specified syntax. and outputs the bitstream.

[0044] The inverse quantization and inverse orthogonal transformation unit 109 performs the orthogonal transformation supplied from the orthogonal transformation and quantization unit 107. The quantized residual is inversely quantized and inversely orthogonally transformed to calculate the residual, and the calculated residual is used as the decoded image. The signal is supplied to the image signal superimposing unit 110 .

[0045] The decoded image signal superimposing unit 110 outputs a predicted image signal according to the determination by the prediction method determining unit 105. The residuals that have been inversely quantized and inversely orthogonally transformed by the inverse quantization and inverse orthogonal transformation unit 109 are superimposed to form a decoded image. The decoded image signal superimposing unit 110 generates a decoded image and stores it in the decoded image memory 104. The coded image is filtered to reduce block distortion and other distortions caused by coding. The decoded image may then be stored in the decoded image memory 104.

[0046] The encoding information storage memory 111 stores the prediction mode (integer) determined by the prediction method determination unit 105. In the case of inter prediction, the code The coding information stored in the coding information storage memory 111 includes the determined motion vectors, the reference list, Inter prediction information such as L0 and L1 reference indexes, historical predicted motion vector candidate list, etc. In the case of the merge mode of the inter prediction, the coding information storage memory 111 includes The encoded information to be stored includes the merge index, sub-block merge index, and the above information. Inter prediction information (sub-block merge flag) indicating whether the sub-block is in the multi-mode or not is included. In the case of the inter-prediction predicted motion vector mode, the coding information storage memory 111 The encoded information to be stored includes the above information as well as the inter prediction mode, predicted motion vector, etc. An index, a differential motion vector, and information indicating whether it is a sub-block predicted motion vector mode. It includes inter prediction information such as sub-block prediction motion vector flags. In the case of prediction, the coding information stored in the coding information storage memory 111 includes the determined input. It includes intra prediction information such as intra prediction mode.

[0047] FIG. 2 shows the configuration of an image decoding apparatus according to an embodiment of the present invention, which corresponds to the image encoding apparatus of FIG. The image decoding device according to the embodiment includes a bitstream decoding unit 201, a block block division unit 202, inter prediction unit 203, intra prediction unit 204, coding information storage memory 205, an inverse quantization and inverse orthogonal transformation unit 206, a decoded image signal superimposition unit 207, and a decoded image memory Equipped with 208 harpoons.

[0048] The decoding process of the image decoding device of FIG. 2 is performed by the decoding device provided inside the image coding device of FIG. Since it corresponds to the processing, the coding information storage memory 205 in FIG. The configurations of the conversion unit 206, the decoded image signal superimposing unit 207, and the decoded image memory 208 are shown in FIG. The image encoding device includes an encoding information storage memory 111, an inverse quantization and inverse orthogonal transformation unit 109, a decoder, and a The decoded image signal superimposing unit 110 and the decoded image memory 104 and their corresponding functions It has.

[0049] The bitstream supplied to the bitstream decoder 201 conforms to the rules of the specified syntax. The bit string decoding unit 201 decodes the separated first bit string and Sequence, picture, slice, coding block unit information and coding block unit Specifically, the bitstream decoding unit 201 obtains the coded information by inter-coding block units. Prediction mode PredMode determines whether the prediction is intra prediction (MODE_INTER) or intra prediction (MODE_INTRA). When the prediction mode is inter prediction (MODE_INTER), the bitstream decoding unit 201 Flag to determine whether it is in merge mode, merge index if in merge mode, sub Block merge flag, inter prediction mode if predicted motion vector mode, prediction Motion vector index, differential motion vector, sub-block predicted motion vector flag, etc. The coding information (inter prediction information) is decoded according to a specified syntax and coded. information (inter prediction information) via the inter prediction unit 203 and the block division unit 202 The prediction mode is intra prediction (MODE_INTRA). In this case, coding information (intra prediction information) such as intra prediction mode is specified in the specified syntax. Therefore, the encoded information (intra prediction information) is decoded and transmitted to the inter prediction unit 203 or the intra prediction unit 204. The data is supplied to the coding information storage memory 205 via the prediction unit 204 and the block division unit 202. The bit stream decoding unit 201 decodes the separated second bit stream and performs orthogonal transform and quantization. The orthogonally transformed and quantized residual is supplied to the inverse quantization and inverse orthogonal transformation unit 206. do.

[0050] The inter prediction unit 203 performs the inter prediction when the prediction mode PredMode of the coding block to be processed is set to inter prediction. When the prediction (MODE_INTER) is in the predicted motion vector mode, the coding information storage memory 205 A plurality of predicted motion vectors are generated using the coding information of the already decoded image signal stored in the The motion vector predictor candidates are derived, and the derived motion vector predictor candidates are used as the motion vector predictor candidates described later. The inter prediction unit 203 registers the motion vector predicted candidate in the motion vector predicted candidate list. From among the plurality of motion vector predictor candidates recorded, a bitstream decoder 201 decodes and supplies a motion vector predictor corresponding to the motion vector predictor index, and decoding the bitstream; The motion vector is calculated from the differential motion vector decoded by the unit 201 and the selected predicted motion vector. The calculated motion vector is stored in the coded information storage memory 205 together with other coded information. The coding information of the coding block to be supplied and stored here is the prediction mode PredMode , flags predFlagL0[xP][yP], predFlag indicating whether to use L0 prediction and L1 prediction L1[xP][yP], L0, 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 the The Prediction Mode PredMo is an index indicating the position of the top left pixel of the coding block in the Prediction Mode PredMo. When de is inter prediction (MODE_INTER) and the inter prediction mode is L0 prediction (Pred_L0) , the flag predFlagL0 indicating whether to use L0 prediction is 1, and the flag predFlagL0 indicating whether to use L1 prediction is 2. The flag predFlagL1 indicating this is 0. When the inter prediction mode is L1 prediction (Pred_L1), The flag predFlagL0 indicating whether to use L0 prediction is 0, and the flag predFlagL1 indicating whether to use L1 prediction is 1. The flag predFlagL1 is set to 1. When the inter prediction mode is bi-prediction (Pred_BI), Flag indicating whether prediction is used or not predFlagL0, Flag indicating whether L1 prediction is used or not predFlagL1 and predFlagL2 are both set to 1. Furthermore, the prediction mode PredMode of the coding block to be processed is When merging in inter prediction (MODE_INTER) mode, merging candidates are derived. Using the coding information of the already decoded coding block stored in the storage memory 205 , multiple merge candidates are derived and registered in a merge candidate list described later. The merge candidates are decoded by the bitstream decoder 201 and supplied from among the multiple merge candidates registered in the Select a merge candidate corresponding to the bin index, and perform L0 prediction of the selected merge candidate. Flags predFlagL0[xP][yP], predFlagL1[xP][yP], and L0 , the reference index of L1 refIdxL0[xP][yP], refIdxL1[xP][yP], the motion vector of L0, L1 Inter prediction information such as mvL0[xP][yP] and mvL1[xP][yP] is stored in the encoding information storage memory 205. Here, xP and yP are the indexes that indicate the position of the top left pixel of the coding block in the picture. The detailed configuration and operation of the inter prediction unit 203 will be described later.

[0051] The intra prediction unit 204 determines whether the prediction mode PredMode of the coding block to be processed is intra. In the case of prediction (MODE_INTRA), intra prediction is performed. The encoding information includes an intra-prediction mode. The decoding unit 201 decodes the image data according to the intra prediction mode included in the coded information. A predicted image signal is generated by intra-prediction from the decoded image signal stored in the memory 208. The generated predicted image signal is supplied to the decoded image signal superimposing unit 207. 204 corresponds to the intra prediction unit 103 of the image encoding device 100. The same processing as that of the intra prediction unit 103 is performed.

[0052] The inverse quantization and inverse orthogonal transformation unit 206 performs orthogonal transformation and quantization on the decoded bit stream by the bit stream decoding unit 201. The inverse orthogonal transform and inverse quantization are performed on the residual, and the inverse orthogonal transformed and inverse quantized residual is get.

[0053] The decoded image signal superimposing unit 207 superimposes the predicted image signal obtained by the inter prediction unit 203. or a predicted image signal obtained by intra-prediction in the intra prediction unit 204, and The decoded image is obtained by superimposing the residuals that have been inverse orthogonally transformed and inversely quantized by the orthogonal transform unit 206. The decoded image signal is stored in the decoded image memory 208. When storing the decoded image in the memory 208, the decoded image signal superimposing unit 207 performs coding on the decoded image. After filtering to reduce block distortion etc., the decoded image is stored in the decoded image memory 208. It may be stored.

[0054] Next, the operation of the block division unit 101 in the image coding device 100 will be described. Figure 3 shows the division of an image into treeblocks and the further division of each treeblock. First, the input image is divided into tree blocks of a predetermined size. Each tree block is sorted in a predetermined order, i.e., a raster order (step S1001). The tree block is scanned in scan order (step S1002) and the inside of the tree block to be processed is divided. (Step S1003).

[0055] FIG. 7 is a flowchart showing the detailed operation of the division process in step S1003. It is determined whether or not the block to be processed is to be divided into four (step S1101).

[0056] If it is determined that the processing block should be divided into four, the processing block is divided into four (step Step S1102). For each block into which the processing target block is divided, That is, the scanning is performed in the order of upper left, upper right, lower left, and lower right (step S1103). 6A is an example of a scan order, and 601 in FIG. 6A is an example in which the block to be processed is divided into four. The numbers 0 to 3 in 601 of A indicate the order of processing. For each divided block, the division process of FIG. 7 is recursively executed (step S1104 ).

[0057] If it is determined that the block to be processed is not to be divided into four, it is divided into two or three (step S1 105).

[0058] FIG. 8 is a flowchart showing the detailed operation of the 2-3 division process in step S1105. First, we decide whether to divide the block to be processed into 2 or 3 parts. It is determined whether or not to perform either of these (step S1201).

[0059] If it is not determined that the processing block should be divided into 2-3 blocks, i.e., if it is determined that no division should be made, In other words, the division is completed by the recursive division process (step S1211). No further recursive division processing is performed on the blocks that have been divided.

[0060] If it is determined that the processing block should be divided into 2-3 blocks, the processing block is further divided into 2 blocks. It is determined whether or not to divide (step S1202).

[0061] If it is determined that the processing block is to be divided into two, the processing block is divided into upper and lower (vertical ) (step S1203), and based on the result, the block to be processed is The block is divided into two parts vertically (step S1204), or the block to be processed is divided into two parts vertically (step S1205). Divide the image into two on the right (horizontal direction) (step S1205). The target block is divided into two parts, top and bottom (vertical direction), as shown in 602 of FIG. 6B, and the steps are As a result of the step S1205, the block to be processed is divided into left and right (horizontal) blocks as shown in 604 of FIG. 6D. (Directional) It is divided into two parts.

[0062] In step S1202, if it is not determined that the block to be processed is to be divided into two In other words, if it is determined that the block should be divided into three, the block to be processed is divided into top, middle and bottom (vertical direction). Based on the result of the determination, the block to be processed is moved up or down (step S1206). Divide the target block into three parts (vertically) (step S1207), or divide the target block into three parts (left, middle, right, and As a result of step S1207, the processing object is divided into three parts (horizontal direction) (step S1208). The block is divided into three parts (vertical direction) - top, middle and bottom, as shown in 603 of FIG. 6C. As a result of step S1208, the block to be processed is divided into left, center, and right (horizontal) blocks as shown in 605 of FIG. 6E. (Directional) It is divided into three parts.

[0063] Step S1204, Step S1205, Step S1207, Step S1208 After performing either of the above, for each block into which the processing target block is divided, The numbers 0 to 605 in FIGS. 2 shows the order of processing. For each divided block, 2-3 division processing in Fig. 8 is performed. The process is recursively executed (step S1210).

[0064] The recursive block division explained here is performed by dividing the number of blocks into multiple blocks. The necessity of division may be restricted depending on the size of the image. By making a prearrangement between the decoder and the decoder, it is possible to realize a configuration that does not transmit information. Alternatively, the encoding device may determine information that limits the necessity of division and record it in the bit string. , may be realized by transmitting the information to the decoding device.

[0065] When a block is divided, the block before the division is called the parent block, and each block after the division is called the parent block. The blocks are called child blocks.

[0066] Next, the operation of the block division unit 202 in the image decoding device 200 will be described. The block division unit 202 performs the same processing procedure as the block division unit 101 of the image encoding device 100. However, the block division of the image coding device 100 is The unit 101 applies optimization techniques such as optimal shape estimation by image recognition and strain rate optimization, The optimal block division shape is determined, whereas the block division in the image decoding device 200 is determined. The dividing unit 202 divides the blocks by decoding the block division information recorded in the bit string. The difference is that the division shape is determined.

[0067] The syntax (syntax rules for bit strings) related to block division in the first embodiment is shown in FIG. coding_quadtree() represents the syntax for dividing a block into four parts. _type_tree() represents the syntax for splitting a block into two or three parts. it is a flag that indicates whether to divide the block into four parts. If you want to divide the block into four parts, use qt If you do not want to split into four, set qt_split=0. If you want to split into four (qt_split=1), For each block divided into four, recursively divide it into four (coding_quadtree(0), codin g_quadtree(1), coding_quadtree(2), coding_quadtree(3), arguments 0 to 3 correspond to the 6 in Figure 6A. (This corresponds to the number 01.) If you do not split into four (qt_split=0), follow the multi_type_tree() , determines the subsequent split. mtt_split is a flag indicating whether to split further. If further splitting is required (mtt_split=1), indicate whether to split vertically or horizontally. The flag mtt_split_vertical determines whether to split the image into two or three parts. mtt_split_vertical=1 indicates splitting in the vertical direction. mtt_split_vertical=0 indicates splitting horizontally, and mtt_split_binary=1 indicates splitting horizontally. mtt_split_binary=0 indicates that it will be split into two, and mtt_split_binary=0 indicates that it will be split into three. tt_split_binary=1), and recursively split each block into two (multi_t type_tree(0), multi_type_tree(1), arguments 0 to 1 correspond to 602 or 604 in Figure 6B to D. (These numbers correspond to the numbers.) When splitting into three (mtt_split_binary=0), the following is true for each of the three split blocks: and recursively splits the tree (multi_type_tree(0), multi_type_tree(1), multi_type_ tree(2), 0 to 2 correspond to the numbers 603 in Figure 6B or 605 in Figure 6E.) mtt_spli Hierarchical block division by recursively calling multi_type_tree until t=0. Do the following.

[0068] <Inter prediction> The inter prediction method according to the embodiment is performed by the inter prediction unit 102 of the image encoding device shown in FIG. This is performed in the inter prediction unit 203 of the image decoding device in FIG.

[0069] The inter prediction method according to the embodiment will be described with reference to the drawings. The method is performed in both the encoding and decoding processes on a coding block basis.

[0070] <Explanation 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 image encoding device of FIG. The normal motion vector predictor mode derivation unit 301 derives a plurality of normal motion vector predictor candidates. A predicted motion vector is selected by the motion vector prediction function, and the selected predicted motion vector is compared with the detected motion vector. The differential motion vector is calculated based on the detected inter prediction mode, reference index, and motion vector. The calculated differential motion vector is the inter prediction in 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 predictive motion vector mode derivation unit 301 will be described later.

[0071] The normal merge mode derivation unit 302 derives multiple normal merge candidates and This inter prediction information is used for the normal merge mode. The result is supplied to the prediction mode determination unit 305. The reasoning behind this will be explained later.

[0072] The sub-block prediction motion vector mode derivation unit 303 calculates a plurality of sub-block prediction motion vectors. A motion vector candidate is derived to select a sub-block predictor motion vector, and the selected sub-block predictor motion vector is A differential motion vector is calculated between the estimated motion vector and the detected motion vector. Inter prediction mode, reference index, motion vector, calculated differential motion vector This becomes inter prediction information for the sub-block prediction motion vector mode. is supplied to the inter prediction mode determination unit 305.

[0073] The sub-block merge mode derivation unit 304 derives multiple sub-block merge candidates. Select sub-block merging candidates and obtain inter-prediction information for sub-block merging modes This inter prediction information is supplied to the inter prediction mode determination unit 305.

[0074] The inter prediction mode determination unit 305 determines whether the normal prediction motion vector mode is derived from the normal prediction motion vector mode derivation unit 301 or the normal prediction motion vector mode derivation unit 302. A merge mode derivation unit 302, a sub-block predicted motion vector mode derivation unit 303, a sub-block Based on the inter prediction information supplied from the block merge mode derivation unit 304, The inter prediction mode determination unit 305 determines the prediction information. The measurement information is supplied to the motion compensation prediction unit 306 .

[0075] The motion compensation prediction unit 306 stores the decoded image in the decoded image memory 1 based on the determined inter prediction information. The motion compensation prediction unit 306 performs inter prediction on the reference image signal stored in the motion compensation prediction unit 306. The detailed configuration and processing will be described later.

[0076] <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 image decoding device of FIG.

[0077] The normal motion vector predictor mode derivation unit 401 derives a plurality of normal motion vector predictor candidates. a predicted motion vector is selected, and the selected predicted motion vector and the decoded differential motion vector are The sum of the decoded inter prediction mode and reference index is calculated and used as the motion vector. In this case, the motion vector is the inter prediction information in the normal prediction motion vector mode. The center prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the motion vector measurement mode derivation unit 401 will be described later.

[0078] The normal merge mode derivation unit 402 derives multiple normal merge candidates and selects the normal merge candidates. Select this to get the inter prediction information for normal merge mode. The merge mode derivation unit 402 normally supplies the merge mode to the motion compensation prediction unit 406 via 408. The detailed configuration and processing will be described later.

[0079] The sub-block prediction motion vector mode derivation unit 403 calculates a plurality of sub-block prediction motion vectors. A motion vector candidate is derived to select a sub-block predictor motion vector, and the selected sub-block predictor motion vector is The sum of the estimated motion vector and the decoded differential motion vector is calculated and used as the motion vector. The decoded inter prediction mode, reference index, and motion vector are used for sub-block prediction. This inter prediction information is used as the inter prediction information for the motion vector mode. is supplied to the motion compensation prediction unit 406 via

[0080] The sub-block merge mode derivation unit 404 derives multiple sub-block merge candidates. Select sub-block merging candidates and obtain inter-prediction information for sub-block merging modes This inter prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. .

[0081] The motion compensation prediction unit 406 stores the decoded image data in the decoded image memory 2 based on the determined inter-prediction information. 08. The motion compensation prediction unit 406 performs inter-prediction on the reference image signal stored in the motion compensation prediction unit 406. The detailed configuration and processing of the motion compensation prediction unit 306 on the encoding side are the same as those of the motion compensation prediction unit 306 on the encoding side.

[0082] <Normal predicted motion vector mode derivation part (normal AMVP)> The normal predicted motion vector mode derivation unit 301 in FIG. 17 derives spatial predicted motion vector candidates. 321, a temporal motion vector predictor candidate derivation unit 322, and a historical motion vector predictor candidate derivation unit 3 23, a predicted motion vector candidate supplementation unit 325, a normal motion vector detection unit 326, a predicted motion vector The motion vector selection unit 327 includes a motion vector candidate selection unit 328 .

[0083] The normal predicted motion vector mode derivation unit 401 in FIG. 23 derives spatial predicted motion vector candidates. unit 421, a temporal motion vector predictor candidate derivation unit 422, and a historical motion vector predictor candidate derivation unit 4 23, a motion vector predictor candidate supplementation unit 425, a motion vector predictor candidate selection unit 426, a motion vector The vector adder 427 is included.

[0084] The normal predicted motion vector mode derivation unit 301 on the encoding side and the normal predicted motion vector mode derivation unit 302 on the decoding side The processing procedure of the torque mode derivation unit 401 is shown in the flowcharts of FIGS. 19 and 25. 19 is a diagram showing the normal motion vector mode derivation unit 301 on the encoding side. 25 is a flowchart showing a procedure for deriving a predicted motion vector mode. 1 shows a procedure for deriving a normal predicted motion vector mode by the normal motion vector mode derivation unit 401. This is a flowchart.

[0085] <Normal prediction motion vector mode derivation part (normal AMVP): explanation on the encoding side> The normal predicted motion vector mode derivation process on the encoding side will be described with reference to FIG. In the explanation of the processing procedure of FIG. 19, the word "normal" shown in FIG. 19 may be omitted.

[0086] First, the normal motion vector detection unit 326 detects the inter prediction mode and the reference index. Then, a normal motion vector is detected (step S100 in FIG. 19).

[0087] Next, the spatial prediction motion vector candidate derivation unit 321 and the temporal prediction motion vector candidate derivation unit 3 22, a history predicted motion vector candidate derivation unit 323, a predicted motion vector candidate supplement unit 325, a predicted motion vector candidate A predicted motion vector candidate selection unit 327 and a motion vector subtraction unit 328 select a normal predicted motion vector The differential motion vectors of the motion vectors used in inter prediction of the mode are set for L0 and L1 respectively. Specifically, the predicted value of the block to be processed is calculated (steps S101 to S106 in FIG. 19). Prediction mode PredMode is inter prediction (MODE_INTER), and inter prediction mode is L0 prediction (Pr ed_L0), calculate the motion vector predictor candidate list mvpListL0 of L0, and The motion vector mvpL0 of L0 is selected, and the differential motion vector mvdL0 of the motion vector mvL0 of L0 is calculated. If the inter prediction mode of the target block is L1 prediction (Pred_L1), the predicted motion vector of L1 is A motion vector candidate list mvpListL1 is calculated, a motion vector predictor mvpL1 is selected, and the motion vector of L1 is Calculate the differential motion vector mvdL1 of the current block mvL1. When bi-prediction (Pred_BI) is used, both L0 prediction and L1 prediction are performed, and the predicted motion vector of L0 is A motion vector candidate list mvpListL0 is calculated, a motion vector predictor mvpL0 for L0 is selected, and the motion vector of L0 is A differential motion vector mvdL0 of the vector mvL0 is calculated, and a predicted motion vector candidate of L1 is calculated. A complementary list mvpListL1 is calculated, and a predicted motion vector mvpL1 of L1 is calculated. Then, the differential motion vector mvdL1 of the corresponding vector mvL1 is calculated.

[0088] The differential motion vector calculation process is performed for each of L0 and L1. Therefore, in the following explanation, L0 and L1 are represented as a common LX. In the process of calculating the differential motion vector of L0, X of LX is 0, and In the process of calculating the motion vector of LX, X of LX is 1. If you refer to the information in the other list instead of the LX during the process of adding the other list, is expressed as LY.

[0089] When the motion vector mvLX of LX is used (step S102 in FIG. 19: YES), Calculate the candidate predicted motion vectors of LX and construct a candidate predicted motion vector list mvpListLX of LX. (Step S103 in FIG. 19). A spatial motion vector predictor candidate derivation unit 321, a temporal motion vector predictor candidate derivation unit 322, a history A motion vector predictor candidate deriving unit 323 and a motion vector predictor candidate supplementing unit 325 generate a plurality of motion vector predictors. The motion vector predictor candidate list mvpListLX is constructed by deriving motion vector candidates. The detailed processing procedure of step S103 will be described later with reference to the flowchart of FIG. do.

[0090] Next, the motion vector predictor candidate selection unit 327 selects a motion vector predictor candidate list for LX. Select a predicted motion vector mvpLX for LX from the mvpListLX (step S104 in FIG. 19). Here, in the motion vector predictor candidate list mvpListLX, a certain element (counting from 0) The motion vector mvLX and the motion vector predictor candidate are expressed as mvpListLX[i]. The difference between each candidate motion vector predictor mvpListLX[i] stored in the list mvpListLX is The differential motion vectors are calculated for each of the coded frames. The coding amount is calculated for each element (predictor motion vector candidate) of the predictor motion vector candidate list mvpListLX. Then, among the elements registered in the motion vector predictor candidate list mvpListLX, The candidate motion vector predictor mvpListLX[i] that minimizes the amount of coding for each candidate motion vector predictor is The motion vector predictor mvpLX is selected as the motion vector predictor mvpLX, and its index i is obtained. There are multiple candidates for the predicted motion vector with the minimum amount of generated code in the candidate list mvpListLX. In this case, the index i in the motion vector predictor candidate list mvpListLX is a small number. The candidate motion vector predictor mvpListLX[i] represented by the following is used as the optimal motion vector predictor mvpLX. Select it and get its index i.

[0091] Next, the motion vector subtraction unit 328 subtracts the motion vector mvLX of LX selected from the motion vector mvLX of LX. Subtract the predicted motion vector mvpLX, mvdLX = mvLX - mvpLX The differential motion vector mvdLX of LX is calculated as follows (step S105 in FIG. 19).

[0092] <Normal predicted motion vector mode derivation unit (normal AMVP): Decoding side explanation> Next, the normal predicted motion vector mode processing procedure on the decoding side will be described with reference to FIG. On the other hand, a spatial prediction motion vector candidate derivation unit 421 and a temporal prediction motion vector candidate derivation unit 422 are provided. 22, the history predicted motion vector candidate derivation unit 423, the predicted motion vector candidate supplementation unit 425, The motion vectors used in inter prediction in normal prediction motion vector mode are set for each of L0 and L1. Specifically, the process of the block to be processed is performed as follows (steps S201 to S206 in FIG. 25). Prediction mode PredMode is inter prediction (MODE_INTER) and the target block is inter prediction When the mode is L0 prediction (Pred_L0), the predicted motion vector candidate list mvpListL0 of L0 is calculated. Then, the predicted motion vector mvpL0 is selected, and the motion vector mvL0 of L0 is calculated. If the inter prediction mode of the target block is L1 prediction (Pred_L1), the predicted motion vector of L1 is used. A motion vector candidate list mvpListL1 is calculated, a motion vector predictor mvpL1 is selected, and the motion vector of L1 is If the inter prediction mode of the block to be processed is bi-predictive (Pred_BI), Both L0 prediction and L1 prediction are performed, and the L0 predicted motion vector candidate list mvpListL0 is calculated. Then, the predicted motion vector mvpL0 of L0 is selected, and the motion vector mvL0 of L0 is calculated. In both cases, a motion vector predictor candidate list mvpListL1 of L1 is calculated, and the motion vector predictor of L1 is Then, the motion vector mvpL1 for L1 is calculated, and the motion vector mvL1 for L2 is calculated.

[0093] As with the encoding side, the decoding side also performs motion vector calculation processing for each of L0 and L1. However, the process is common to both L0 and L1. L1 is represented as a common LX. LX is used for inter prediction of the coding block being processed. This represents the inter prediction mode. In the process of calculating the L0 motion vector, X is 0, and in the L1 In the process of calculating the motion vector of L, X is 1. During processing, the LX being calculated is not based on the same reference list, but on information from another reference list. When referencing one reference list, the other reference list is represented as LY.

[0094] When the motion vector mvLX of LX is used (step S202 in FIG. 25: YES), LX Calculate the candidate predicted motion vectors of LX and construct a candidate predicted motion vector list mvpListLX of LX. (Step S203 in FIG. 25). A spatial motion vector predictor candidate derivation unit 421, a temporal motion vector predictor candidate derivation unit 422, a history A motion vector predictor candidate deriving unit 423 and a motion vector predictor candidate supplementing unit 425 generate a plurality of motion vector predictors. Then, motion vector predictor candidates are calculated and a motion vector predictor candidate list mvpListLX is constructed. The detailed processing procedure of step S203 will be described later with reference to the flowchart of FIG. do.

[0095] 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 predicted motion vector mvpListLX[mvpIdxLX] corresponding to pIdxLX is used as the selected predicted motion vector. The vector mvpLX is extracted (step S204 in FIG. 25).

[0096] Then, the motion vector adder 427 decodes the bit stream and supplies it to the bit stream decoder 201. Add the differential motion vector mvdLX of LX and the predicted motion vector mvpLX of LX, mvLX = mvpLX + mvdLX The motion vector mvLX of LX is calculated as follows (step S205 in FIG. 25).

[0097] <Normal predicted motion vector mode derivation part (normal AMVP): Motion vector prediction method> FIG. 20 shows a normal prediction motion vector mode derivation process of the image coding apparatus according to the embodiment of the present invention. Functions common to the motion vector mode derivation unit 301 and the normal predicted motion vector mode derivation unit 401 of the image decoding device 10 is a flowchart showing the processing procedure of a normal predicted motion vector mode derivation process having the following formula.

[0098] The normal predicted motion vector mode derivation unit 301 and the normal predicted motion vector mode derivation unit 40 1 includes a motion vector predictor candidate list mvpListLX. The mvpListLX has a list structure and is a prediction vector that indicates the location within the motion vector prediction candidate list. The motion vector index and the motion vector predictor candidate corresponding to the index are used as elements. The predicted motion vector index number starts from 0. The motion vector predictor candidate list mvpListLX is started and stored in the storage area of ​​the motion vector predictor candidate list mvpListLX. In this embodiment, the motion vector predictor candidate list mvpListLX contains at least At least two candidate motion vector predictors (inter prediction information) can be registered. Furthermore, the motion vector predictor registered in the motion vector predictor candidate list mvpListLX is The variable numCurrMvpCand, which indicates the number of rule candidates, is set to 0.

[0099] The spatial motion vector predictor candidate derivation units 321 and 421 derive the spatial motion vector predictor candidate from the adjacent block on the left side. In this process, candidates for predicted motion vectors are derived from the adjacent block on the left ( A0 or A1) inter prediction information, i.e., whether or not a motion vector predictor candidate is available. A flag indicating whether the motion vector is a predicted motion vector mv LXA is derived, and the derived mvLXA is added to the motion vector predictor candidate list mvpListLX (FIG. 20 In the case of L0 prediction, X is set to 0, and in the case of L1 prediction, X is set to 1 (hereinafter, Next, the spatial prediction motion vector candidate derivation units 321 and 421 select the adjacent spatial prediction motion vector candidate on the upper side. In this process, the candidate predicted motion vectors are derived from the adjacent block on the upper side. Inter prediction information of the block (B0, B1, or B2 in FIG. 11), i.e., predicted motion vector A flag indicating whether a motion candidate is available or not, and a reference to the motion vector, reference index, etc. The predicted motion vector mvLXA and mvLXB are derived based on the calculated motion vector mvLXA and mvLXB. If so, mvLXB is added to the motion vector predictor candidate list mvpListLX (step S3 in FIG. 20). 02). The processing in steps S301 and S302 in FIG. 20 is performed by determining the position and number of adjacent blocks to be referenced. The difference is whether the candidate predicted motion vector for the coding block can be used. The flag availableFlagLXN indicates whether the motion vector is available or not, and the motion vector mvLXN and the reference index refIdxN( N indicates A or B, and so on.

[0100] Next, the temporal motion vector predictor candidate derivation units 322 and 422 calculate the temporal motion vector predictor candidate for the current processing target picture. A candidate motion vector predictor is derived from a block in a picture that is different in time from the image. In this process, motion vector predictor candidates of coding blocks of pictures at different times are used. The flag availableFlagLXCol indicates whether the motion vector mvLXCol and the reference index are available. The reference list refIdxCol and the reference list listCol are derived, and mvLXCol is used to create the predicted motion vector candidate list m Add it to vpListLX (step S303 in FIG. 20).

[0101] Note that temporal prediction is performed in units of sequences (SPS), pictures (PPS), or slices. It is assumed that the processing of the motion vector candidate derivation units 322 and 422 can be omitted.

[0102] Next, the history prediction motion vector candidate derivation units 323 and 423 derive the history prediction motion vector candidate. The historical predicted motion vector candidates registered in the supplementary list HmvpCandList are used as predicted motion vector candidates. The mvpListLX is added to the auxiliary list mvpListLX (step S304 in FIG. 20). The registration process will be described in detail later with reference to the flowchart of FIG.

[0103] Next, the motion vector predictor candidate supplementation units 325 and 425 generate the motion vector predictor candidate list mv Add motion vector predictor candidates with a predetermined value, such as (0,0), until pListLX is satisfied ( S305 in Figure 20).

[0104] <Normal merge mode derivation part (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, and a Candidate derivation unit 342, average merge candidate derivation unit 344, history merge candidate derivation unit 345, merge It includes a candidate supplementation unit 346 and a merge candidate selection unit 347 .

[0105] 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, and a Candidate derivation unit 442, average merge candidate derivation unit 444, history merge candidate derivation unit 445, merge It includes a candidate supplementation unit 446 and a merge candidate selection unit 447 .

[0106] FIG. 21 shows the normal merge mode derivation unit 302 and A normal merge mode having a function common to the normal merge mode derivation unit 402 of the image decoding device and the normal merge mode derivation unit 402 of the image decoding device. 10 is a flowchart illustrating the procedure of a code derivation process.

[0107] The following describes the various steps in order. The slice type slice_type is explained as a B slice, but the case of a P slice is explained as follows. However, if the slice type slice_type is P slice, the inter prediction model There is only L0 prediction (Pred_L0) as a code, and L1 prediction (Pred_L1) and bi-prediction (Pred_BI) are also supported. Since there is no L1, processing related to L1 can be omitted.

[0108] The normal merge mode derivation unit 302 and the normal merge mode derivation unit 402 determine the merge candidate list. The merge candidate list mergeCandList has a list structure, A merge index that indicates the location within the merge candidate list and the merge candidate corresponding to the index. There is a memory area for storing merge candidates as elements. The merge index number is 0. The merge candidates are stored in the merge candidate list (mergeCandList) starting from In the following process, the merge index i registered in the merge candidate list mergeCandList is used. The merge candidates are represented by mergeCandList[i]. The candidate list mergeCandList must contain at least six merge candidates (inter-prediction information). Furthermore, the merge candidates registered in the mergeCandList The variable numCurrMergeCand, which indicates the number of merge candidates, is set to 0.

[0109] The spatial merge candidate derivation unit 341 and the spatial merge candidate derivation unit 441 are The encoded information stored in the encoded information storage memory 111 or the encoded information storage memory 205 of the image decoding device From the coded information stored in the block, the spatial information from the blocks adjacent to the left and above the block to be processed is Derive merge candidates A and B, and create a merge candidate list mergeCandL. ist (step S401 in FIG. 21). Define N to indicate one of the temporal merge candidates Col. The inter prediction information of block N is Flag availableFlagN indicating whether it can be used as a spatial merge candidate, spatial merge candidate N The L0 reference index refIdxL0N and the L1 reference index refIdxL1N are The L0 prediction flag predFlagL0N indicates whether L1 prediction is performed or not, and the L1 prediction flag predFlagL0N indicates whether L1 prediction is performed or not. The L1 prediction flag predFlagL1N, the L0 motion vector mvL0N, and the L1 motion vector mvL1N are used. However, in this embodiment, the blocks included in the coding block to be processed are derived. Since merge candidates are derived without referring to the inter prediction information of the block, Spatial merge candidates that use inter prediction information of blocks included in the block are not derived.

[0110] Next, the temporal merge candidate derivation unit 342 and the temporal merge candidate derivation unit 442 determine different time derive temporal merge candidates from the pictures between, and the derived temporal merge candidates are called merge candidates The time merge candidate is registered in the list mergeCandList (step S402 in FIG. 21). flag availableFlagCol indicating whether L0 prediction of temporal merge candidates is performed or not. L0 prediction flag predFlagL0Col indicating whether L1 prediction is performed and L1 prediction flag predFlagL0Col indicating whether L1 prediction is performed. The flag predFlagL1Col, the motion vector mvL0Col of L0, and the motion vector mvL1Col of L1 are Derive.

[0111] Note that time markers can be set in units of sequences (SPS), pictures (PPS), or slices. The processing of the merge candidate derivation unit 342 and the temporal merge candidate derivation unit 442 can be omitted. Let's say.

[0112] Next, the history merge candidate derivation unit 345 and the history merge candidate derivation unit 445 perform history prediction. Mark the historical predicted motion vector candidates registered in the motion vector candidate list HmvpCandList. The candidate is registered in the mergeCandList (step S403 in FIG. 21).

[0113] The number of merge candidates registered in the merge candidate list mergeCandList is numCurrMergeC If and is smaller than the maximum number of merge candidates MaxNumMergeCand, the merge candidate list mergeCandL The number of merge candidates registered in ist is numCurrMergeCand, and the maximum number of merge candidates is MaxNumMergeCand. The history merge candidates are derived with nd as the upper limit and registered in the merge candidate list mergeCandList. can be.

[0114] Next, the average merge candidate derivation unit 344 and the average merge candidate derivation unit 444 calculate the merge candidates. The average merge candidate is derived from the complement list mergeCandList, and the derived average merge candidate is merged. The merge candidate list mergeCandList is then added to the mergeCandList (step S404 in FIG. 21).

[0115] The number of merge candidates registered in the merge candidate list mergeCandList is numCurrMergeC If and is smaller than the maximum number of merge candidates MaxNumMergeCand, the merge candidate list mergeCandL The number of merge candidates registered in ist is numCurrMergeCand, and the maximum number of merge candidates is MaxNumMergeCand. The average merge candidate is calculated with nd as the upper limit and registered in the merge candidate list mergeCandList. can be.

[0116] Here, the average merge candidate is the first merge candidate registered in the merge candidate list mergeCandList. The motion vectors of the merge candidate and the second merge candidate are averaged for each of the L0 prediction and the L1 prediction. The resulting motion vector is a new merge candidate.

[0117] Next, the merge candidate supplementation unit 346 and the merge candidate supplementation unit 446 generate a merge candidate list. The number of merge candidates registered in mergeCandList, numCurrMergeCand, is less than the maximum number of merge candidates, M If it is smaller than axNumMergeCand, the merge candidate list mergeCandList contains The number of merge candidates numCurrMergeCand is the maximum number of merge candidates MaxNumMergeCand. The merge candidates are derived and registered in the merge candidate list mergeCandList (step S4 in FIG. 21). 05). In P slices, the maximum number of merge candidates is MaxNumMergeCand. A merge candidate having a prediction mode of L0 prediction (Pred_L0) with a value of (0,0) is added. In B slices, the prediction mode with a motion vector of (0,0) is bi-predictive (Pred_BI). The reference index when adding a merge candidate is the same as the index of the merge candidate already added. This is different from the reference index used.

[0118] Next, the merge candidate selection unit 347 and the merge candidate selection unit 447 select a merge candidate list Select a merge candidate from the merge candidates registered in mergeCandList. The merge candidate selection unit 347 selects merge candidates by calculating the code amount and distortion amount. , a merge index indicating the selected merge candidate, inter prediction information of the merge candidate, The inter-prediction mode determination unit 305 supplies the inter-prediction mode data to the motion compensation prediction unit 306. The merge candidate selection unit 447 on the side selects merge candidates based on the decoded merge index. The motion compensation prediction unit 406 selects a merge candidate and supplies the selected merge candidate to the motion compensation prediction unit 406 .

[0119] In the normal merge mode derivation unit 302 and the normal merge mode derivation unit 402, a certain coding block If the block size (product of width and height) is less than 32, the parent block of that encoding block Then, in all child blocks, merge candidates are derived from the parent block. The merge candidate is used, provided that the parent block size is 32 or more and the block is within the screen. Only if it fits.

[0120] <Update of historical motion vector predictor candidate list> Next, the encoding information storage memory 111 on the encoding side and the encoding information storage memory 20 on the decoding side are Methods for initializing and updating the historical motion vector predictor candidate list HmvpCandList in preparation for 5 FIG. 26 shows the procedure for initializing and updating the history motion vector predictor candidate list. 1 is a flowchart illustrating the above.

[0121] In this embodiment, the historical motion vector predictor candidate list HmvpCandList is updated based on the coding information. This is implemented in the information storage memory 111 and the coded information storage memory 205. The prediction unit 102 and the inter-prediction unit 203 include a history prediction motion vector candidate list update unit. It may be set to update the historical motion vector predictor candidate list HmvpCandList.

[0122] At the beginning of the slice, the historical motion vector prediction candidate list HmvpCandList is initialized. On the encoding side, the prediction method decision unit 105 decides whether to use the normal predicted motion vector mode or the normal merge mode. When the selected motion vector prediction candidate list HmvpCandList is updated, The prediction information decoded by the bitstream decoding unit 201 is in the normal predicted motion vector mode or the normal In the merge mode, the historical motion vector predictor candidate list HmvpCandList is updated.

[0123] Used when performing inter prediction in normal predicted motion vector mode or normal merge mode. The inter prediction information is used as the inter prediction information candidate hMvpCand in the history prediction motion vector candidate list. The inter prediction information candidate hMvpCand is registered in the HmvpCandList. The reference index for L0 and L1, refIdxL1, indicates whether L0 prediction is performed. an L0 prediction flag predFlagL0 and an L1 prediction flag predFl indicating whether or not L1 prediction is performed; It includes agL1, a motion vector mvL0 for L0, and a motion vector mvL1 for L1.

[0124] The encoding information storage memory 111 on the encoding side and the encoding information storage memory 205 on the decoding side are provided. The elements (i.e., the image) registered in the history motion vector predictor candidate list HmvpCandList are Among the inter prediction information candidates, there is inter prediction information with the same value as the inter prediction information candidate hMvpCand. If it exists, remove the element 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, , delete the first element of the history predicted motion vector candidate list HmvpCandList, and The inter-prediction information candidate hMvpCand is added to the end of the vector candidate list HmvpCandList.

[0125] 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 for 05 is six.

[0126] First, the historical motion vector predictor candidate list HmvpCandList is initialized for each slice. (Step S2101 in FIG. 26) At the beginning of the slice, the historical predicted motion vector candidate list Hm Add the historical predicted motion vector candidates to all elements of vpCandList, and The number of historical motion vector predictor candidates NumHmvpCand registered in the candidate list HmvpCandList Set the value to 6. Or, at the beginning of the slice, add the history motion vector predictor candidate list HmvpCandL All elements of ist are emptied, and the motion vector prediction candidate list HmvpCandList is registered. The number of historical motion vector predictor candidates (current number of candidates) NumHmvpCand can be set to 0. good.

[0127] Note that the initialization of the historical motion vector predictor candidate list HmvpCandList is performed on a slice-by-slice basis ( However, it is possible to perform this on a picture-by-picture, tile-by-tile or tree block basis. It may be performed on a row-by-row basis.

[0128] Figure 38 shows the history of motion vector prediction candidates added by initializing the list HmvpCandList. 10 is a table showing an example of candidate historical motion vectors. An example is shown in which the number of images is 4. The number of motion vector predictor candidates varies from NumHmvpCand-1 to 0 depending on the slice type. The inter prediction information with the value (0, 0) of the vector mvLXHmvp (X is 0 or 1) is converted into the historical prediction motion vector The motion vector candidate is added to the history prediction motion vector candidate list HmvpCandList as a history prediction vector candidate. Fill the motion vector candidate list with historical candidates. At this time, the historical predicted motion vector index is used. Start from the reference index hMvpIdx (the number of historical motion vector predictor candidates NumHmvpCand-1). The index refIdxLX (X is 0 or 1) contains a value ranging from 0 to (the number of reference pictures, numRefIdx-1) in increments of 1. After that, the overlap between the history motion vector predictor candidates is eliminated. It is allowed and the reference index refIdxLX is set to 0. All values ​​are set in NumHmvpCand, the number of historical motion vector predictor candidates, and the value of NumHmvpCand By setting a fixed value, invalid historical motion vector predictor candidates are eliminated. The historical predicted motion vectors that are likely to be added to the candidate vector list or merge candidate list. From the candidates with large values ​​of index hMvpIdx, the reference index ref, which generally has a high selection rate, is selected. By assigning a small value to IdxLX, the coding efficiency can be improved.

[0129] In addition, the list of motion vector prediction candidates is updated in units of slices. By filling the number of historical motion vector predictor candidates, the number of historical motion vector predictor candidates can be treated as a fixed value. Therefore, for example, the process of deriving a history predicted motion vector candidate and the process of deriving a history merge candidate can be simplified. This can be done.

[0130] Here, the value of the motion vector is set to (0, 0), which generally has a high selection probability. For example, values ​​such as (4,4), (0,32), and (-128,0) can be used to calculate the differential motion vector. Alternatively, multiple predetermined values ​​may be set to improve the coding efficiency of the differential motion vector. The rate may be improved.

[0131] Also, the history predicted motion vector index hMvpIdx is set to (the number of history predicted motion vector candidates N umHmvpCand-1), and the reference index refIdxLX (X is 0 or 1) starts from 0 (reference It is supposed to set a value incremented by 1 up to the number of reference pictures (numRefIdx-1), but The historical predicted motion vector index hMvpIdx may start from zero.

[0132] Figure 39 shows the history of motion vector prediction candidates added by initializing the list HmvpCandList. 10 is a table showing another example of candidate historical motion vector predictors. In this example, the number of reference pictures is two. The reference index is set so that there is no overlap between the historical motion vector predictor candidates in each element of pCandList. Either the value of the variable refIdxLX (X is 0 or 1) or the value of the motion vector mvLXHmvp (X is 0 or 1) The inter-prediction information, which differs in type, is added as a historical predicted motion vector candidate. The vector candidate list is filled. At this time, the historical predicted motion vector index hMvpIdx Starting from (the number of history motion vector predictor candidates NumHmvpCand-1), the reference index refId xLX (X is 0 or 1) is incremented by 1 from 0 to (number of reference pictures numRefIdx-1). After that, the reference index refIdxLX is set to 0, and a different value of the movement vector is set to Add the vector mvLXHmvp as a historical motion vector predictor candidate. All values ​​are set in NumHmvpCand, the number of historical motion vector predictor candidates, and the value of NumHmvpCand By setting ∑ k = ...

[0133] In this way, the list of candidate predicted motion vectors is created for each slice, and the candidate predicted motion vectors are stored in the list of candidate predicted motion vectors without overlapping. By filling the vector candidates, the coding block can be further coded as described below. The merge candidate derivation unit 345 in the regular merge mode derivation unit 302 determines the merge candidate after the history merge candidate derivation unit 345. The processing of the filling section 346 can be omitted, and the amount of processing can be reduced.

[0134] Here, the absolute value of each component of the motion vector mvLXHmvp is set to 0 or 1. If there is no overlap between vector candidates, the absolute value of each component of the motion vector mvLXHmvp is set to 1 or greater. It may be larger.

[0135] Also, the history predicted motion vector index hmvpIdx is calculated by (the number of history predicted motion vector candidates N umHmvpCand-1), and the reference index refIdxLX (X is 0 or 1) starts from 0 (reference It is supposed to set a value incremented by 1 up to the number of reference pictures (numRefIdx-1), but The historical predicted motion vector index hMvpIdx may start from zero.

[0136] Figure 40 shows the history of motion vector prediction candidates added by initializing the list HmvpCandList. 10 is a table showing another example of historical motion vector predictor candidates.

[0137] Here is an example where the slice type is B slice and the number of reference pictures is 1. The historical predicted motion vector candidate is assigned to each element of the historical predicted motion vector candidate list HmvpCandList. To avoid duplication, the reference index refIdxLX is set to 0 and the value of the motion vector mvLXHmvp is set to Different inter-prediction information is added as a historical predicted motion vector candidate, and the historical predicted motion vector is At this time, the historical predicted motion vector index hMvpIdx is used as ( Starting from the number of historical motion vector predictor candidates NumHmvpCand-1), the reference index refIdxLX (X is 0 or 1) is 0 and the value of the motion vector mvLXHmvp is different. Set all values ​​to the number of historical motion vector predictor candidates NumHmvpCand and By setting the value of NumHmvpCand, the number of motion vector candidates, to a fixed value, invalid historical motion vector predictor candidates can be Eliminate.

[0138] In this way, by setting the reference index refIdxLX to 0, the number of reference pictures Since initialization can be performed without taking into consideration the above, processing can be simplified.

[0139] Here, the absolute value of each component of the motion vector mvLXHmvp is set to a power of 0, 1, or 2. If the reference index is 0 and there is no overlap between the historical motion vector predictor candidates, the motion vector is The absolute value of each component of the torque mvLXHmvp may be a power of 3, 4, or any other value. It can also be set to

[0140] Also, the history predicted motion vector index hMvpIdx is set to (the number of history predicted motion vector candidates N umHmvpCand-1), and the reference index refIdxLX (X is 0 or 1) is 0. Although the values ​​of mvLXHmvp are different from each other, the historical prediction motion vector The index hMvpIdx may start from 0.

[0141] Next, for each coding block in the slice, the following historical motion vector predictor candidate list Hmvp The CandList update process is repeated (steps S2102 to S2111 in FIG. 26).

[0142] First, the initial setting is performed for each coding block. Set the value of the parameter "identicalCandExist" to FALSE (false) and delete the target index that indicates the candidate for deletion. The index removeIdx is set to 0 (step S2103 in FIG. 26).

[0143] It is determined whether or not there is an inter-prediction information candidate hMvpCand to be registered (steps in FIG. 26 ). The prediction method determination unit 105 on the encoding side determines whether the normal prediction motion vector mode or When the normal merge mode is determined, or when the bitstream decoding unit 201 on the decoding side performs normal prediction, When decoded as a motion vector mode or normal merge mode, the inter prediction information The information is set as the inter prediction information candidate hMvpCand to be registered. Intra prediction mode, sub-block prediction motion vector mode or sub-block merge mode, or when the bitstream decoding unit 201 on the decoding side determines that the bitstream is an intra-prediction mode, Decoded as sub-block predicted motion vector mode or sub-block merge mode In this case, the historical motion vector predictor candidate list HmvpCandList is not updated, and the registered image is There is no inter prediction information candidate hMvpCand. If it does not exist, steps S2105 to S2106 are skipped (step S in FIG. 26). 2104: NO). If there is an inter-prediction information candidate hMvpCand to be registered, The processing from S2105 onwards is carried out (step S2104 in FIG. 26: YES).

[0144] Next, the input to be registered is added to each element of the history motion vector predictor candidate list HmvpCandList. The elements (inter prediction information) with the same value as the inter prediction information candidate hMvpCand, i.e., the same elements It is determined whether or not it exists (step S2105 in FIG. 26). 10 is a flowchart of a processing procedure. (Step S2121 in FIG. 27: NO), the historical motion vector predictor candidate list HmvpCa Since the ndList is empty and there are no identical candidates, steps S2122 to S2125 in FIG. 27 are executed. The number of historical motion vector predictor candidates NumHmvpC is If the value of and is greater than 0 (YES in step S2121 of FIG. 27), the history predicted motion vector The process of step S2123 is repeated for the data index hMvpIdx from 0 to NumHmvpCand-1. First, the history of the motion vector predictor candidate list is returned (steps S2122 to S2125 in FIG. 27). The hMvpIdx-th element HmvpCandList[hMvpIdx] counting from 0 in the list is the inter prediction information candidate hM It is compared with vpCand to see if it is the same (step S2123 in FIG. 27). Step S2123: YES), a flag "identicalCandE" indicating whether an identical candidate exists or not, Set the value of xist to TRUE and the deletion target index remo to indicate the position of the element to be deleted. Set the current value of the history predicted motion vector index hMvpIdx to veIdx and check the same element. If they are not the same (step S2123 in FIG. 27: NO), increase hMvpIdx by 1. If the history predicted motion vector index hMvpIdx is less than or equal to NumHmvpCand-1, If so, the process from step S2123 onwards is carried out.

[0145] Returning to the flowchart of FIG. 26 again, the historical predicted motion vector candidate list HmvpCandList The element shift and addition process is performed (step S2106 in FIG. 26). Element shift / addition processing of the history predicted motion vector candidate list HmvpCandList in step S2106 First, the historical motion vector predictor candidate list HmvpCandList is Either remove the stored elements and then add the new elements, or add the new elements without removing any elements. Specifically, the flag "identicalCandE" indicates whether or not an identical candidate exists. xist is compared to determine whether it is TRUE or NumHmvpCand is 6 (step S2141 in FIG. 28). ) The flag identicalCandExist indicates whether an identical candidate exists or not. If the number of candidates NumHmvpCand is 6, any of the conditions is satisfied (step S2141 in FIG. 28: YES), excluding the elements stored in the historical motion vector predictor candidate list HmvpCandList Add a new element from the index i. Set the initial value of the index i to the value of removeIdx + 1. The element shift process in step S2143 is repeated from the initial value of NumHmvpCand to NumHmvpCand. Steps S2142 to S2144 of 28. HmvpCandList[i - 1] is set to HmvpCandList[i] Shift the elements forward by copying the elements of i (step S2143 in FIG. 28), and Increment by 1 (steps S2142 to S2144 in FIG. 28). The (NumHmvpCand-1)th HmvpCandList, counting from 0, corresponds to the end of the motion vector candidate list. The inter prediction information candidate hMvpCand is added to t[NumHmvpCand-1] (step S214 in FIG. 28). 5) Finish the element shift and addition process of this history predicted motion vector candidate list HmvpCandList. On the other hand, the flag identicalCandExist, which indicates whether an identical candidate exists, is set to TRUE. If neither of the conditions of NumHmvpCand is 6 is satisfied (step S2141 in FIG. 28: NO), ), without excluding the elements stored in the history motion vector predictor candidate list HmvpCandList, The inter prediction information candidate hMvpCand is added to the end of the historical prediction motion vector candidate list (see Figure 2). 8, step S2146). Here, the end of the history motion vector predictor candidate list is from 0 to It is the NumHmvpCand-th HmvpCandList[NumHmvpCand] counting from the beginning. Increment the element shift and The addition process is then completed.

[0146] FIG. 31 is a diagram illustrating an example of a process for updating the history motion vector predictor candidate list. The elements (inter prediction information) are registered in the historical predicted motion vector candidate list HmvpCandList When adding a new element to the list, the previous element of the history motion vector predictor candidate list HmvpCandList is added. The new inter-prediction information is compared with the previous inter-prediction information (Fig. 31A). If the value is the same as the third element HMVP2 from the beginning of the vector candidate list HmvpCandList, The element HMVP2 is deleted from the motion vector predictor candidate list HmvpCandList, and the following elements HMVP3 to HM VP5 is shifted forward one by one and stored in the history prediction motion vector candidate list HmvpCandLis A new element is added to the end of t (FIG. 31B), and the history motion vector predictor candidate list HmvpCan The update of the dList is completed (Figure 31C).

[0147] <Historical motion vector predictor candidate derivation process> Next, the history of predicted motion vector candidates in the normal predicted motion vector mode derivation unit 301 on the encoding side is The prediction motion vector mode derivation unit 323 and the normal prediction motion vector mode derivation unit 401 on the decoding side The processing procedure of step S304 in FIG. 20, which is common processing in the driver candidate derivation unit 423, is Method for deriving historical motion vector predictor candidates from historical motion vector predictor candidate list HmvpCandList FIG. 29 is a flowchart illustrating the procedure for deriving a historical motion vector predictor candidate. This is a flow chart.

[0148] The number of current motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpLis The maximum number of elements in tLX (here, 2) or more, or the number of history motion vector predictor candidates is NumHm If the value of vpCand is 0 (NO in step S2201 in FIG. 29), step S22 in FIG. The process from S2202 to S2209 is omitted, and the procedure for deriving the historical motion vector predictor candidate is completed. The current number of motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpLis If the number of elements of tLX is smaller than 2, and the number of history motion vector predictor candidates NumHmvpCa If the value of nd is greater than 0 (YES in step S2201 in FIG. 29), Process steps S2202 to S2209.

[0149] Next, the index i is 1 to 4 and the number of historical motion vector predictor candidates is numCheckedHMVP The process of steps S2203 to S2208 in FIG. 29 is repeated until the smaller value of Cand is reached. The current number of motion vector predictor candidates, nu, is returned (steps S2202 to S2209 in FIG. 29). When mCurrMvpCand is equal to or greater than 2, which is the maximum number of elements in the motion vector predictor candidate list mvpListLX. (Step S2203 in FIG. 29: NO), Steps S2204 to S2209 in FIG. 29 The process for deriving the historical motion vector predictor candidate is omitted, and the procedure for deriving the current motion vector predictor candidate is terminated. The number of motion vector candidates, numCurrMvpCand, is the maximum number of elements in the motion vector predictor candidate list, mvpListLX. If it is smaller than 2 (step S2203 in FIG. 29: YES), step S2 in FIG. Processes 204 and beyond.

[0150] Next, the process from step S2205 to S2207 is performed when Y is 0 and 1 (L0 and L1). This is performed for each of the current predicted motion vectors (steps S2204 to S2208 in FIG. 29). The number of motion vector predictor candidates, numCurrMvpCand, is the maximum number of elements in the motion vector predictor candidate list, mvpListLX. If the number is 2 or more (step S2205 in FIG. 29: NO), go to step S2206 in FIG. The process of steps S2201 to S2209 is omitted, and the procedure for deriving historical motion vector predictor candidates is terminated. The current number of motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpListL If the number of elements in X is smaller than 2 (step S2205 in FIG. 29: YES), 9, the processing from step S2206 onwards is carried out.

[0151] Next, the motion vector to be coded / decoded is included in the history predicted motion vector candidate list HmvpCandList. The element of the reference index is the same as the reference index refIdxLX of the vector, and the predicted motion vector If the element is different from any element in the vector list mvpListLX (step S2206 in FIG. 29), :YES), the numCurrMvpCand-th element mvpL counting from 0 in the motion vector predictor candidate list istLX[numCurrMvpCand] is the LY of the history predicted motion vector candidate HmvpCandList[NumHmvpCand - i] (Step S2207 in FIG. 29), and the current motion vector predictor candidate Increment the number of historical motion vector predictor candidates, numCurrMvpCand, by 1. In the list, there is a reference index that is the same as the reference index refIdxLX of the motion vector to be coded / decoded. element of the motion vector predictor list mvpListLX, and an element different from any element of the motion vector predictor list mvpListLX is If not (step S2206 in FIG. 29: NO), the additional processing of step S2207 is skipped. Upload.

[0152] The above processing from step S2205 to S2207 in Figure 29 is performed on both L0 and L1. (Steps S2204 to S2208 in FIG. 29). Increment the index i by 1. , the index i is the smaller value of 4 or the number of historical motion vector predictor candidates NumHmvpCand. In the following cases, the process from step S2203 onward is performed again (steps S2202 to S2203 in FIG. 29). S2209).

[0153] <History merge candidate derivation process> Next, the history merge candidate derivation unit 345 of the normal merge mode derivation unit 302 on the encoding side, This is a common process between the normal merge mode derivation unit 402 and the history merge candidate derivation unit 445. 21, which is the processing procedure of step S404, The method for deriving merge candidates will now be described in detail. Figure 30 shows the history merge candidate derivation process. 10 is a flowchart for explaining the process.

[0154] First, initialization is performed (step S2301 in FIG. 30). Set the value of FALSE for each (rrMergeCand -1)th element and set the variable numOrigMergeCand to the current Set numCurrMergeCand to the number of elements currently in the merge candidate list.

[0155] Next, set the initial value of the index hMvpIdx to 1, and then calculate from this initial value to NumHmvpCand. 30. Then, the additional processing from step S2303 to step S2310 in FIG. 30 is repeated (FIG. 3 Steps S2302 to S2311 of step 0. Elements registered in the current merge candidate list If the number of merge candidates is not less than (MaxNumMergeCand-1), the merge Since merge candidates have been added to all elements in the candidate list, the merge candidate derivation process is The process ends (NO in step S2303 in FIG. 30). If the number of elements in the merge candidate list, numCurrMergeCand, is less than or equal to (MaxNumMergeCand-1), Execute the process from step S2304 onwards. Set the value of sameMotion to FALSE (see Figure 30). (Step S2304) Next, the initial value of index i is set to 0, and The processing of steps S2306 and S2307 in FIG. 30 is repeated up to numOrigMergeCand-1 (FIG. 30 (S2305 to S2308). Counting from 0 in the history motion vector prediction candidate list (NumHmvp Cand - hMvpIdx)-th element HmvpCandList[NumHmvpCand- hMvpIdx] is the merge candidate list Counting from 0, compare whether the value is the same as the i-th element mergeCandList[i] (step in Figure 30). P2306).

[0156] The same value of a merge candidate means that all components (inter prediction mode, reference If the values ​​of the merge candidates (reference index, motion vector) are the same, the merge candidates are considered to have the same value. If the complements are the same and isPruned[i] is FALSE (YES in step S2306 of FIG. 30), Set both sameMotion and isPruned[i] to TRUE (step S2307 in FIG. 30). If the values ​​are not the same (NO in step S2306 in FIG. 30), the process in step S2307 is performed. The process from step S2305 to step S2308 in FIG. 30 is repeated. When the process is completed, compare whether sameMotion is FALSE (step S230 in FIG. 30). 9), if sameMotion is FALSE (YES in step S2309 of FIG. 30), that is, That is, the (NumHmvpCand - hMvpIdx)th element counting from 0 in the history motion vector candidate list. Since the element HmvpCandList[NumHmvpCand - hMvpIdx] does not exist in mergeCandList, it is not a merge candidate. The numCurrMergeCand-th mergeCand in the list is mergeCandList[numCurrMergeCand], which stores the history predicted movement vector. The (NumHmvpCand - hMvpIdx)th element of the candidate list, counting from 0, is HmvpCandList[NumHmv pCand - hMvpIdx] and increment numCurrMergeCand by 1 (step 30 in Figure 30). The index hMvpIdx is incremented by 1 (step S23 in FIG. 30). 02), steps S2302 to S2311 in FIG. 30 are repeated.

[0157] When all elements in the history motion vector prediction candidate list have been checked, or the merge candidate list Once merge candidates have been added to all elements of the record, the process of deriving merge candidates for this history is complete. .

[0158] <Motion compensation prediction processing> The motion compensation prediction unit 306 predicts the current block being predicted during encoding. The motion compensation prediction unit 306 also obtains the inter prediction information. The inter prediction information is acquired from the inter prediction mode determination unit 305. The image data and motion vectors are derived and stored in the decoded image memory 104 as specified by the reference index. The reference picture to be used is moved from the same position as the image signal of the prediction block by the amount of the motion vector. After acquiring the image signal at the position where the image signal is input, a predicted signal is generated.

[0159] In inter prediction, the inter prediction mode is a single reference picture, such as L0 prediction or L1 prediction. In the case of prediction from a reference picture, the prediction signal obtained from one reference picture is used as the motion compensated prediction signal. The inter prediction mode is BI prediction, and the prediction mode is from two reference pictures. In the case of prediction, the weighted average of the predicted signals obtained from two reference pictures is used as the motion vector. The motion compensation prediction signal is supplied to the prediction method determination unit 105. The ratio of the weighted average of the predictions is 1:1, but weighted averages can also be performed using other ratios. For example, if the picture interval between the picture to be predicted and the reference picture is close, The weighting ratio may be increased as the value of the pixel increases. This may be done using a correspondence table of combinations of channel intervals and weighting ratios.

[0160] The motion compensation prediction unit 406 has the same function as the motion compensation prediction unit 306 on the encoding side. The compensation prediction unit 406 outputs the inter prediction information to the normal prediction motion vector mode derivation unit 401, A normal merge mode derivation unit 402, a sub-block predicted motion vector mode derivation unit 403, a sub-block predicted motion vector mode derivation unit 404, a sub-block predicted motion vector mode derivation unit 405, a sub-block predicted motion vector mode derivation unit 406, a sub-block predicted motion vector mode derivation unit 407, a sub-block predicted motion vector mode derivation unit 408, a sub-block predicted motion vector mode derivation unit The block merge mode is obtained from the block merge mode derivation unit 404 via the switch 408. The prediction unit 406 supplies the obtained motion compensation prediction signal to the decoded image signal superimposing unit 207 .

[0161] <About inter prediction mode> The process of making predictions from a single reference picture is defined as uni-prediction, and in the case of uni-prediction, it is called L0 prediction. Or L1 prediction, which is a prediction using one of the two reference pictures registered in the reference lists L0 and L1. Predictions are made using either one of them.

[0162] FIG. 32 shows a uni-predictive picture in which the L0 reference picture (RefL0Pic) is the picture to be processed. 33 shows the case where the time is before CurPic. 1. Similarly, the case where the reference picture to be processed is later than the current picture is shown in FIG. 32 and 33, the reference picture for L0 prediction is changed to the reference picture for L1 prediction (RefL1Pi It is also possible to replace it with c) and perform uni-prediction.

[0163] The process of making predictions from two reference pictures is defined as bi-prediction, and in the case of bi-prediction, L0 prediction is used. The bi-prediction is expressed as BI prediction using both L0 and L1 prediction. The reference picture for L1 prediction is located before the current picture, and the reference picture for L1 prediction is located before the current picture. Figure 35 shows a case where the picture is bi-predictive and has a reference to L0 prediction. This indicates that the reference picture and the reference picture for L1 prediction are located at a time earlier than the picture being processed. FIG. 36 shows a bi-predictive coding example in which a reference picture for L0 prediction and a reference picture for L1 prediction are processed. This shows the case where the picture is located after the picture to be processed.

[0164] In this way, the relationship between the L0 / L1 prediction type and time is that L0 is the past direction and L1 is the future direction. In the case of bi-prediction, the same reference picture can be used. It is also possible to perform L0 prediction and L1 prediction using the same. The decision as to whether to use L0 prediction or bi-prediction is made based on, for example, whether to use L1 prediction or not. The determination is made based on information (for example, a flag) indicating whether or not the message is being sent.

[0165] <About reference indexes> In the embodiment of the present invention, in order to improve the accuracy of the motion compensation prediction, multiple This allows the optimum reference picture to be selected from a number of reference pictures. The reference picture used in the motion compensation prediction is used as a reference index, and The index is coded into the bitstream along with the differential motion vector.

[0166] <Motion compensation processing based on normal predicted motion vector mode> The motion compensation prediction unit 306 is also shown as the inter prediction unit 102 on the encoding side in FIG. In this way, the inter prediction mode determination unit 305 performs normal prediction motion vector mode derivation. When the inter prediction information by the unit 301 is selected, the inter prediction information is - The inter prediction mode of the block currently being processed is acquired from the prediction mode determination unit 305. The estimation mode, reference index, and motion vector are derived to generate a motion compensated prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.

[0167] Similarly, the motion compensation prediction unit 406 also performs the same function as the inter prediction unit 203 on the decoding side in FIG. As shown, during the decoding process, the switch 408 is turned on to the normal predicted motion vector mode derivation unit 40 When connected to 1, inter prediction by the normal prediction motion vector mode derivation unit 401 The information is acquired and the inter prediction mode and reference index of the currently processed block are The generated motion compensation prediction signal is then used to derive a motion vector. The signal is supplied to a decoded image signal superimposing unit 207.

[0168] <Motion compensation processing based on normal merge mode> The motion compensation prediction unit 306 is also shown as the inter prediction unit 102 on the encoding side in FIG. In this way, the inter prediction mode determination unit 305 determines whether the normal merge mode is When inter prediction information by the inter prediction mode is selected, this inter prediction information is used as the inter prediction mode. the inter prediction mode of the block currently being processed, obtained from the prediction mode determination unit 305; A reference index and a motion vector are derived, and a motion compensation prediction signal is generated. The compensated prediction signal is supplied to the prediction method determination unit 105 .

[0169] Similarly, the motion compensation prediction unit 406 also performs the same function as the inter prediction unit 203 on the decoding side in FIG. As shown, during the decoding process, switch 408 is normally connected to merge mode derivation unit 402. If so, the inter prediction information is obtained from the normal merge mode derivation unit 402, and the current processing The inter prediction mode, reference index, and motion vector of the block being processed are The generated motion compensation prediction signal is used as a decoded image signal. The paper is supplied to the folding section 207.

[0170] <Motion compensation processing based on sub-block predicted motion vector mode> The motion compensation prediction unit 306 is also shown as the inter prediction unit 102 on the encoding side in FIG. In this way, the inter prediction mode determination unit 305 determines the sub-block predicted motion vector model. When the inter prediction information is selected by the code derivation unit 303, this inter prediction information The inter prediction mode determination unit 305 obtains the inter prediction mode of the block currently being processed. Derives the center prediction mode, reference index, and motion vector, and generates a motion compensated prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.

[0171] Similarly, the motion compensation prediction unit 406 also performs the same function as the inter prediction unit 203 on the decoding side in FIG. As shown, during the decoding process, a switch 408 controls the sub-block predicted motion vector mode. When the sub-block prediction motion vector mode derivation unit 403 is connected to the sub-block prediction motion vector mode derivation unit 403, Inter prediction information is obtained by the current block being processed. The generated code, reference index, and motion vector are derived to generate a motion compensated prediction signal. The resulting motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207 .

[0172] <Motion compensation processing based on sub-block merge mode> The motion compensation prediction unit 306 is also shown as the inter prediction unit 102 on the encoding side in FIG. In this way, the inter prediction mode determination unit 305 includes a sub-block merge mode derivation unit When the inter prediction information by 304 is selected, this inter prediction information is Inter prediction of the block currently being processed, obtained from the prediction mode determination unit 305 The mode, reference index, and motion vector are derived, and a motion compensation prediction signal is generated. The resulting motion compensation prediction signal is supplied to the prediction method determination unit 105.

[0173] Similarly, the motion compensation prediction unit 406 also performs the same function as the inter prediction unit 203 on the decoding side in FIG. As shown, during the decoding process, a switch 408 controls the sub-block merge mode derivation unit 404. , the inter prediction information by the sub-block merge mode derivation unit 404 is and obtains the inter prediction mode and reference index of the currently processed block. , a motion vector is derived, and a motion compensation prediction signal is generated. The generated motion compensation prediction signal is , and is supplied to the decoded image signal superimposing unit 207.

[0174] <Motion compensation processing based on affine transformation prediction> In normal motion vector prediction mode and normal merge mode, the following flags are used: The following flags are used to indicate whether motion compensation is performed in the encoding process. The following flags are used based on the inter-prediction conditions determined by the inter-prediction mode determination unit 305: The bitstream is then coded into the bitstream. Determine whether to perform motion compensation using an affine model based on the following flags in the program: .

[0175] sps_affine_enabled_flag is the flag for motion compensation using the affine model in inter prediction. If sps_affine_enabled_flag is 0, it indicates whether or not affine is available. The motion compensation is suppressed so that it is not based on the affine model. cu_affine_type_flag specifies the CU (Coded Block) syntax of the coded video sequence. If sps_affine_enabled_flag is 1, the encoded video sequence is not transmitted. In this case, affine model motion compensation can be used.

[0176] sps_affine_type_flag is the 6-parameter affine model for inter prediction. Indicates whether motion compensation is available. If sps_affine_type_flag is 0, 6 parameters are used. It is suppressed so that it is not motion compensation by the affine model. Also, cu_affine_type_flag is not conveyed in the CU syntax of a coded video sequence. If e_flag is 1, the coded video sequence is generated using a 6-parameter affine model. If sps_affine_type_flag is not present, it is assumed to be 0. do.

[0177] When decoding a P or B slice, the current CU If r_affine_flag is 1, generate a motion compensation prediction signal for the CU currently being processed. To do this, affine motion compensation is used. If inter_affine_flag is 0, If this is set, no affine model is used for the current CU. If lag is not present, it is assumed to be 0.

[0178] When decoding a P or B slice, in the currently processed CU, If ffine_type_flag is 1, the motion compensation prediction signal for the CU currently being processed is generated. To achieve this, a six-parameter affine model of motion compensation is used. If e_flag is 0, the motion compensation prediction signal for the CU currently being processed is generated. In this paper, motion compensation using a four-parameter affine model is used.

[0179] In motion compensation using the affine model, reference indices and motion vectors are calculated for each subblock. Since the torque is derived, the reference index that is processed in sub-block units is and motion vectors to generate a motion compensated prediction signal.

[0180] The four-parameter affine model is defined as the horizontal and vertical components of the motion vectors of the two control points. The motion vector of a sub-block is derived from the four vertical component parameters. This is a mode in which motion compensation is performed at the pixel position. (Second embodiment) In the first embodiment, the history prediction motion vector is used in the normal prediction motion vector mode and the normal merge mode. The order of referencing the elements (candidates) of the vector candidate list was the same. In this embodiment, the following additions and modifications are made to the first embodiment: History prediction The reference order when using the motion vector candidate list is the same as that of the normal predicted motion vector in the second embodiment. In the torque mode, the steps are performed in the reverse order to those in the first embodiment, as shown in FIG. In the normal merge mode of this embodiment, as shown in FIG. 45, the process is performed in the same order as in the first embodiment. That is, the history prediction is performed in the normal predicted motion vector mode and the normal merge mode. The order in which the candidates included in the motion vector candidate list are referenced is reversed. In normal motion vector prediction mode, elements in the history motion vector prediction candidate list are In normal merge mode, the elements are added to the candidate motion vector predictor list in order of their historical predictions. The elements in the predicted motion vector candidate list are sorted into the predicted motion vector candidate list in order from the newest element. will be added to.

[0181] <History predicted motion vector candidate list> Here, the history predicted motion vector candidate list As shown in FIG. 41, in the block to be coded, The inter prediction information used in the inter prediction is registered as an inter prediction information candidate hM vpCand, and the history of past use is the history predicted motion vector candidate list Hm In Figure 41, the history motion vector predictor candidate list stores six elements. It is a list structure that can store elements, and elements stored first are retrieved in order, first in, first out. The basic storage operation is the FIFO (First-In, First-Out) method.

[0182] Here, as an example, the maximum number of elements that can be stored in HmvpCandList is set to 1 on the encoding side and 1 on the decoding side. Although the arrangement will be explained as six, it is not particularly limited and may be six or more. Also, the maximum number of elements that can be stored in HmvpCandList is 5 or less. For example, the maximum number of elements in the motion vector predictor candidate list mvpListLX may be Inter prediction information candidates, such as prime number, maximum number of merging candidates, and maximum number of sub-block merging candidates The maximum number of elements in HmvpCandList may be the same as the maximum number of elements in each mode. The HmvpCandList may be configured to be linked to the maximum number of elements of the center prediction information candidates.

[0183] The maximum number of elements in this HmvpCandList is included in the syntax element of the bitstream. In this way, the signal may be transmitted from the encoding side to the decoding side.

[0184] As shown in Figure 41, HmvpCandList is a list of Six elements can be stored in the tail, position 5, and elements are filled in order from position 0 to position 5. The positions 0 to 5 can be used as the historical predicted motion vector index hMvpId For example, position 0 can be expressed as hMVpIdx[0], and position 5 can be expressed as hMVpIdx[5]. The number of elements stored in pCandList is managed by NumHmvpCand, and is stored in the range from 0 to the maximum number of elements, 6. Manage the increase and decrease of elements.

[0185] When adding a new element when the maximum number of elements is stored in HmvpCandList, As shown in FIG. 42, the inter prediction information candidate hMvpCand is newly recorded. When registering as a history, delete the first element at position 0 and move each element position by one. As a result of the shift, the number of stored elements decreases by one as shown in Figure 43. This allows a new element to be stored at position 5 at the end. By storing the candidate hMvpCand in position 5 at the end, a new hMvpCand is added to the HmvpCandList as shown in Figure 44. The element is added.

[0186] <Derivation of historical motion vector predictor candidates in normal motion vector predictor mode in the second embodiment> Processing> Here, the historical predicted motion vector in the normal predicted motion vector mode of the second embodiment is The vector candidate derivation process will be described.

[0187] FIG. 47 shows the normal merge mode in the normal predicted motion vector mode of the second embodiment. The historical motion vector predictor candidate list HmvpCandList is referenced in the reverse order of the reference order of the previous motion vectors. A flowchart for explaining the procedure for deriving a history predicted motion vector candidate when configured to use the -Chart.

[0188] The number of current motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpLis The maximum number of elements in tLX (here, 2) or more, or the number of historical motion vector predictor candidates NumHmvp If the value of Cand is 0 (NO in step S2601 in FIG. 47), The processes from S2602 to S2609 are omitted, and the procedure for deriving a historical motion vector predictor candidate is terminated. The current number of motion vector predictor candidates numCurrMvpCand is the motion vector predictor candidate list mvpListL The value of NumHmvpCand, which is smaller than the maximum number of elements of X (2) and the number of historical motion vector predictor candidates. If is greater than 0 (YES in step S2601 in FIG. 47), step S26 in FIG. Process steps 02 to S2609.

[0189] Next, the index i is set from 0 to 4, and the number of history motion vector predictor candidates NumHmvpCand is set. Steps S2603 to S2608 in FIG. 47 are performed to determine the value obtained by subtracting 1 from the smaller value. The process is repeated (steps S2602 to S2609 in FIG. 47). Current predicted motion vector The number of candidates, numCurrMvpCand, is the maximum number of elements in the motion vector predictor candidate list, mvpListLX, 2 In the above cases (NO in step S2603 in FIG. 47), steps S2604 to S2605 in FIG. The process of 2609 is omitted, and the procedure for deriving the historical motion vector predictor candidate is completed. The number of motion vector predictor candidates numCurrMvpCand is the maximum of the motion vector predictor candidate list mvpListLX. If the number of elements is smaller than 2 (YES in step S2603 in FIG. 47), The processing from step S2604 onwards is carried out.

[0190] Next, the processing from step S2605 to S2607 is performed when the index Y is 0 and 1 (L This is performed for each of the current The number of motion vector predictor candidates numCurrMvpCand is the maximum of the motion vector predictor candidate list mvpListLX. If the number of major elements is 2 or more (NO in step S2605 in FIG. 47), The process from S2606 to S2609 is omitted, and the process for deriving the historical motion vector predictor candidate is The current number of motion vector predictor candidates, numCurrMvpCand, is added to the motion vector predictor candidate list. If the number of elements in the mvpListLX is less than 2, which is the maximum number of elements in the mvpListLX (YES in step S2605 of FIG. 47), S), the process from step S2606 onwards in FIG. 47 is carried out.

[0191] Next, the motion vector to be coded / decoded is included in the history predicted motion vector candidate list HmvpCandList. The element of the reference index is the same as the reference index refIdxLX of the vector, and the predicted motion vector If the element is different from any element in the vector candidate list mvpListLX (step S26 in FIG. 47), 06 YES), the numCurrMvpCand element in the motion vector predictor candidate list, counting from 0 mvpListLX[numCurrMvpCand ] is the LY motion vector of the history predicted motion vector candidate HmvpCandList[i]. A vector is added (step S2607 in FIG. 47), and the current number of motion vector predictor candidates is nu mCurrMvpCand is incremented by 1. The reference index refIdxLX of the motion vector to be coded / decoded is the same as the reference index refIdxLX. The elements of the motion vector predictor candidate list mvpListLX are not different from any elements of the motion vector predictor candidate list mvpListLX. If not (NO in step S2607 in FIG. 47), the additional processing in step S2607 is skipped. Click.

[0192] The above processing from step S2605 to S2607 in Figure 47 is performed on both L0 and L1. (Steps S2604 to S2608 in FIG. 47).

[0193] The index i is incremented by 1 (steps S2602 and S2609 in FIG. 47). The index i is either 4 or the number of historical motion vector predictor candidates NumHmvpCand, whichever is smaller. If the value is equal to or less than the value obtained by subtracting 1 from the value, the process from step S2603 onward is carried out again (step S2604 in FIG. 47). (P2602~S2609).

[0194] As described above, in the normal motion vector prediction mode, the The elements added first (oldest elements) are referenced and added to the motion vector predictor candidate list. will be added.

[0195] <Variation 1> In order to indicate that the historical predicted motion vector candidate list is referenced as in this embodiment, A new history reference flag is introduced to switch between the reference order of the first embodiment and the reference order of this embodiment. This history reference flag may be configured to be replaceable in the syntax of the bitstream. The history reference flag is included in the syntax element and transmitted to the decoding side, and the decoding side then sets this history reference flag in the syntax element It is also possible to obtain the bitstream stored in the <Variation 2> In this embodiment, in the normal predicted motion vector mode, historical prediction is performed as shown in FIG. The motion vector candidate list is referenced one by one from element 0 to element 5 in normal merge mode. As shown in FIG. 45, the motion vector prediction candidate list is sorted in order from element 5 to element 0. The normal predicted motion vector mode and the normal merge mode were used to compare the history predicted motion vectors. This is not limited to this, as long as the order of referencing the vector candidate list is different. For example, In the measured motion vector mode, elements 0 to 2 are referenced, and in the normal merge mode, elements 5 to 2 are referenced. As shown in element 1, the normal predicted motion vector mode and the normal merge mode have history prediction. The number of references to the motion vector candidate list may vary. It is preferable to have a large number of references in the normal merge mode. Now we can change the starting point to refer to elements 4 through 0.

[0196] By configuring the second embodiment as described above, the historical predicted motion vector candidate list can be By using a reference order different from that of the normal motion vector prediction mode, In particular, it is possible to select candidates suitable for each mode. When the normal predicted motion vector mode is selected, the surroundings of the block to be coded are Therefore, the motion vector prediction candidate is often different from the previous situation. Search the complementary list and find elements that are different from the most recent ones and are considered to have relatively low correlation, i.e., By using the oldest elements stored in the The coding efficiency can be improved by selecting suitable candidates for each code.

[0197] In addition, in the normal merge mode, the higher the correlation of the blocks around the target block, the higher the coding efficiency. To improve the accuracy, the list of historical motion vector candidates is searched and the most recent ones are selected. The elements that are considered to be the most suitable, that is, the newest elements stored later, are used as candidates in order. This contributes to improving coding efficiency by providing candidates suitable for the normal merge mode.

[0198] All of the above-described embodiments may be combined in multiple ways.

[0199] In all the embodiments described above, the bitstream output by the image coding device is a specific data so that it can be decoded according to the encoding method used in the embodiment. The image decoding device corresponding to this image coding device has the following data format. It is possible to decode bitstreams of a particular data format.

[0200] To exchange bitstreams between the image coding device and the image decoding device, a wired or When a wireless network is used, the data is bit-coded into a data format suitable for the transmission mode of the communication channel. In this case, the bitstream output by the image coding device may be converted and transmitted. The stream is converted into coded data in a format suitable for the transmission mode of the communication channel and transmitted over the network. a transmitting device that receives coded data from a network and decodes it into a bit stream; The image encoding device includes a receiving device that transmits the image data to the image decoding device. Memory to buffer the output bitstream and packetize the bitstream a packet processing unit and a transmitter for transmitting packetized encoded data over a network; The receiving device receives packetized encoded data via a network. a receiving unit for receiving the encoded data, a memory for buffering the received encoded data, and a packet and a packet processing unit that processes the data to generate a bitstream and provides the bitstream to the image decoding device.

[0201] In addition, by adding a display unit for displaying the image decoded by the image decoding device to the configuration, In this case, the display unit may be a device that displays the decoded image signal generated by the decoded image signal superimposing unit 207. The decoded image signal stored in the decoded image memory 208 is read out and displayed on the screen.

[0202] In addition, by adding an imaging unit to the configuration and inputting the captured image to the image encoding device, In this case, the imaging unit inputs the captured image signal to the block division unit 101. To exert effort.

[0203] FIG. 37 shows an example of the hardware configuration of the encoding / decoding device according to this embodiment. The image encoding device includes the configuration of an image encoding device and an image decoding device according to an embodiment of the present invention. The encoding / decoding device 9000 includes a CPU 9001, a codec IC 9002, an I / O O interface 9003, memory 9004, optical disk drive 9005, network It has a network interface 9006 and a video interface 9009, and each part is connected via a bus. Connected by 9010.

[0204] The image encoding unit 9007 and the image decoding unit 9008 are typically implemented by a codec IC 9002 and The image encoding process of the image encoding device according to the embodiment of the present invention is implemented as an image encoding The image decoding process is executed by the decoding unit 9007 in the image decoding device according to the embodiment of the present invention. The decoding process is performed by the image decoding unit 9008. The I / O interface 9003 For example, a USB interface is used to connect an external keyboard 9104 and mouse 91 The CPU 9001 receives input via the I / O interface 9003. The encoding / decoding device 90 executes the operation desired by the user based on the user's operation. 00. User operations using the keyboard 9104, mouse 9105, etc. , select whether to perform encoding or decoding functions, set the encoding quality, and There are input / output destinations for programs, input / output destinations for images, etc.

[0205] When the user desires to play back images recorded on the disk recording medium 9100 The optical disc drive 9005 reads the bitstream from the inserted disc recording medium 9100. The read bitstream is then sent to the codec I via bus 9010. The image decoder 9008 of the C9002 receives the input bitstream. The image decoding process is performed on the image data in the image decoding device according to the embodiment of the present invention. The image is sent to an external monitor 9103 via a video interface 9009. The encoding / decoding device 9000 has a network interface 9006. It is possible to connect to an external distribution server 9106 and a mobile terminal 9107 via the network 9101. The user converts the image recorded on the disk recording medium 9100 to the image data recorded on the distribution server 9106. If you want to play back images recorded on the mobile terminal 9107, The interface 9006 receives a bitstream from the input disc recording medium 9100. Instead of reading out the bit stream, the bit stream is acquired from the network 9101. When the user desires to play back an image recorded in memory 9004, 004, an image decoding apparatus according to an embodiment of the present invention The image decoding process is performed in the above.

[0206] The user captures an image using an external camera 9102 and encodes it into memory 9004. When an operation is desired, the video interface 9009 receives an image from the camera 9102. The image data is input and sent to the image encoding unit 9007 of the codec IC 9002 via the bus 9010. The image encoding unit 9007 encodes the image input via the video interface 9009. An image encoding process is performed in the image encoding device according to the embodiment of the present invention, and a bitstream is The bitstream is then sent to memory 9004 via bus 9010. The user changes the memory 9004 and sends the bit stream to the disk recording medium 9100. If you wish to record a program, the optical disc drive 9005 will The bitstream is written to the disc recording medium 9100.

[0207] A hardware configuration that has an image encoding device but does not have an image decoding device, or a hardware configuration that has an image decoding device However, it is also possible to realize a hardware configuration that does not include an image coding device. The hardware configuration is, for example, a codec IC 9002, an image encoding unit 9007, or This is realized by replacing the image decoding unit 9008 with the image decoding unit 9009.

[0208] The above encoding and decoding processes are carried out by hardware-based transmission, storage, and reception devices. It can be realized by using ROM (read only memory) or flash memory. Firmware stored in memory, etc., and software executed by a computer, etc. The firmware program and software program may be executed on a computer. The information may be provided by recording it on a recording medium that can be read by a computer or by wired or wireless network. It can be provided from a server via the network, or it can be data from terrestrial or satellite digital broadcasting. It may also be provided as a broadcast.

[0209] The present invention has been described above based on the embodiments. The embodiments are merely examples, and the respective structures thereof are not intended to be limiting. The fact that various variations are possible in the combination of components and treatment processes, and that such variations It will be understood by those skilled in the art that the embodiments are within the scope of the present invention. [Explanation of symbols]

[0210] 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 generation unit, 107 orthogonal transformation and quantization unit, 108 bit string encoding unit, 10 9 inverse quantization and inverse orthogonal transformation unit, 110 decoded image signal superposition unit, 111 coding information storage unit 200 image decoding device; 201 bit string decoding unit; 202 block Division unit, 203 inter prediction unit, 204 intra prediction unit, 205 coding information storage Memory 206 inverse quantization and inverse orthogonal transformation unit, 207 decoded image signal superposition unit, 208 Decoded image memory.< / poc>

Claims

1. 1. An image encoding device that encodes a moving image by dividing each picture of the moving image into blocks using inter prediction based on inter prediction information to form a bitstream, an encoding information storage unit that adds inter prediction information used in inter prediction to a history predicted motion vector candidate list; a spatial motion vector predictor candidate derivation unit that derives spatial motion vector predictor candidates from blocks adjacent to a current block and adds the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation unit that derives a temporal motion vector predictor candidate from a block that is located at the same position as the current block or in a vicinity thereof, and adds the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation unit that derives a history motion vector predictor candidate from the history motion vector predictor candidate list and adds the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation unit that derives spatial merge candidates from blocks adjacent to the target block and adds the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation unit that derives temporal merge candidates from blocks that are located at the same position as the target block or in the vicinity thereof, and adds the temporal merge candidates to the merge candidate list; a history merge candidate derivation unit that derives history merge candidates from the history motion vector predictor candidate list and adds the history merge candidates to the merge candidate list as merge candidates; an average merge candidate derivation unit that derives an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adds the average merge candidate to the merge candidate list; a motion vector predictor candidate selection unit that selects a motion vector predictor used for inter prediction from the motion vector predictor candidate list and determines a motion vector predictor index indicating the motion vector predictor; a merge candidate selection unit that selects a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determines a merge index indicating the merge candidate; an encoding unit that encodes the predicted motion vector index or the merge index; Equipped with the history motion vector predictor candidate derivation unit refers to the history motion vector predictor candidate list in order from the oldest candidate to the newest candidate; The image encoding device, wherein the history merge candidate derivation unit refers to the history merge candidate list in order from newest to oldest.

2. 1. An image coding method for forming a bitstream by coding a moving image using inter prediction based on inter prediction information in units of blocks obtained by dividing each picture of the moving image, the method comprising: an encoding information storing step of adding inter prediction information used in the inter prediction to a history predicted motion vector candidate list; a spatial motion vector predictor candidate derivation step of deriving a spatial motion vector predictor candidate from a block adjacent to the current block and adding the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation step of deriving a temporal motion vector predictor candidate from a block located at the same position as the current block or a block located in the vicinity thereof, and adding the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation step of deriving a history motion vector predictor candidate from the history motion vector predictor candidate list and adding the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation step of deriving spatial merge candidates from blocks adjacent to the target block and adding the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation step of deriving temporal merge candidates from blocks located at the same position as the target block or in the vicinity thereof and adding the temporal merge candidates to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history motion vector predictor candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging the motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a motion vector predictor candidate selection step of selecting a motion vector predictor used for inter prediction from the motion vector predictor candidate list and determining a motion vector predictor index indicating the motion vector predictor; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determining a merge index indicating the merge candidate; an encoding step of encoding the predicted motion vector index or the merge index; Equipped with the derivation of the motion vector predictor candidate history includes referring to the motion vector predictor candidate history list in order from the oldest candidate to the newest candidate; The image coding method, wherein the history merge candidate derivation step refers to candidates included in the history motion vector predictor candidate list in order from newest to oldest.

3. An image encoding program for encoding a moving image using inter prediction based on inter prediction information in units of blocks obtained by dividing each picture of the moving image, the program comprising: an encoding information storing step of adding inter prediction information used in the inter prediction to a history predicted motion vector candidate list; a spatial motion vector predictor candidate derivation step of deriving a spatial motion vector predictor candidate from a block adjacent to the current block and adding the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation step of deriving a temporal motion vector predictor candidate from a block located at the same position as the current block or a block located in the vicinity thereof, and adding the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation step of deriving a history motion vector predictor candidate from the history motion vector predictor candidate list and adding the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation step of deriving spatial merge candidates from blocks adjacent to the target block and adding the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation step of deriving temporal merge candidates from blocks located at the same position as the target block or in the vicinity thereof and adding the temporal merge candidates to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history motion vector predictor candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging the motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a motion vector predictor candidate selection step of selecting a motion vector predictor used for inter prediction from the motion vector predictor candidate list and determining a motion vector predictor index indicating the motion vector predictor; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list and determining a merge index indicating the merge candidate; an encoding step of encoding the predicted motion vector index or the merge index; Equipped with the derivation of the motion vector predictor candidate history includes referring to the motion vector predictor candidate history list in order from the oldest candidate to the newest candidate; The image encoding program is characterized in that the history merge candidate derivation step refers to candidates included in the history motion vector predictor candidate list in order from newest to oldest.

4. 1. An image decoding device that decodes a bitstream obtained by encoding a moving image using inter prediction based on inter prediction information in units of blocks obtained by dividing each picture of the moving image, the image decoding device comprising: an encoding information storage unit that adds inter prediction information used in inter prediction to a history predicted motion vector candidate list; a decoding unit that decodes a motion vector predictor index or a merge index; a spatial motion vector predictor candidate derivation unit that derives spatial motion vector predictor candidates from blocks adjacent to a current block and adds the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation unit that derives a temporal motion vector predictor candidate from a block that is located at the same position as the current block or in a vicinity thereof, and adds the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation unit that derives a history motion vector predictor candidate from the history motion vector predictor candidate list and adds the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation unit that derives spatial merge candidates from blocks adjacent to the target block and adds the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation unit that derives temporal merge candidates from blocks that are located at the same position as the target block or in the vicinity thereof, and adds the temporal merge candidates to the merge candidate list; a history merge candidate derivation unit that derives history merge candidates from the history motion vector predictor candidate list and adds the history merge candidates to the merge candidate list as merge candidates; an average merge candidate derivation unit that derives an average merge candidate having a motion vector obtained by averaging motion vectors of two merge candidates in the merge candidate list and adds the average merge candidate to the merge candidate list; a motion vector predictor candidate selection unit that selects a motion vector predictor to be used for inter prediction from the motion vector predictor candidate list based on the motion vector predictor index; a merge candidate selection unit that selects a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index; Equipped with the history motion vector predictor candidate derivation unit refers to the history motion vector predictor candidate list in order from the oldest candidate to the newest candidate; The image decoding device, wherein the history merge candidate derivation unit refers to candidates included in the history motion vector predictor candidate list in order from newest to oldest.

5. 1. An image decoding method for decoding a bitstream obtained by encoding a moving image using inter prediction based on inter prediction information, for each block obtained by dividing each picture of the moving image, the method comprising: an encoding information storing step of adding inter prediction information used in the inter prediction to a history predicted motion vector candidate list; a decoding step of decoding a motion vector predictor index or a merge index; a spatial motion vector predictor candidate derivation step of deriving a spatial motion vector predictor candidate from a block adjacent to the current block and adding the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation step of deriving a temporal motion vector predictor candidate from a block located at the same position as the current block or a block located in the vicinity thereof, and adding the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation step of deriving a history motion vector predictor candidate from the history motion vector predictor candidate list and adding the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation step of deriving spatial merge candidates from blocks adjacent to the target block and adding the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation step of deriving temporal merge candidates from blocks located at the same position as the target block or in the vicinity thereof and adding the temporal merge candidates to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history motion vector predictor candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging the motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a motion vector predictor candidate selection step of selecting a motion vector predictor to be used for inter prediction from the motion vector predictor candidate list based on the motion vector predictor index; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index; Equipped with the derivation of the motion vector predictor candidate history includes referring to the motion vector predictor candidate history list in order from the oldest candidate to the newest candidate; The image decoding method, wherein the history merge candidate derivation step refers to candidates included in the history motion vector predictor candidate list in order from newest to oldest.

6. An image decoding program for decoding a bitstream obtained by encoding a moving image using inter prediction based on inter prediction information in units of blocks obtained by dividing each picture of the moving image, the image decoding program comprising: an encoding information storing step of adding inter prediction information used in the inter prediction to a history predicted motion vector candidate list; a decoding step of decoding a motion vector predictor index or a merge index; a spatial motion vector predictor candidate derivation step of deriving a spatial motion vector predictor candidate from a block adjacent to the current block and adding the spatial motion vector predictor candidate to a motion vector predictor candidate list; a temporal motion vector predictor candidate derivation step of deriving a temporal motion vector predictor candidate from a block located at the same position as the current block or a block located in the vicinity thereof, and adding the temporal motion vector predictor candidate to the motion vector predictor candidate list; a history motion vector predictor candidate derivation step of deriving a history motion vector predictor candidate from the history motion vector predictor candidate list and adding the history motion vector predictor candidate to the history motion vector predictor candidate list; a spatial merge candidate derivation step of deriving spatial merge candidates from blocks adjacent to the target block and adding the spatial merge candidates to a merge candidate list; a temporal merge candidate derivation step of deriving temporal merge candidates from blocks located at the same position as the target block or in the vicinity thereof and adding the temporal merge candidates to the merge candidate list; a history merge candidate derivation step of deriving a history merge candidate from the history motion vector predictor candidate list and adding the history merge candidate to the merge candidate list as a merge candidate; an average merge candidate derivation step of deriving an average merge candidate having a motion vector obtained by averaging the motion vectors of two merge candidates in the merge candidate list and adding the average merge candidate to the merge candidate list; a motion vector predictor candidate selection step of selecting a motion vector predictor to be used for inter prediction from the motion vector predictor candidate list based on the motion vector predictor index; a merge candidate selection step of selecting a merge candidate having inter prediction information to be used for inter prediction from the merge candidate list based on the merge index; Equipped with the derivation of the motion vector predictor candidate history includes referring to the motion vector predictor candidate history list in order from the oldest candidate to the newest candidate; The image decoding program is characterized in that the history merge candidate derivation step refers to candidates included in the history motion vector predictor candidate list in order from newest to oldest.

7. A method for storing a bit stream generated according to the image coding method of claim 2 on a recording medium.

8. A transmission method for transmitting a bitstream generated according to the image coding method of claim 2.

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