JP2013121166A - Image decoding device, image decoding method, and image decoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which parallel motion compensation prediction processing cannot be performed in performing motion compensation prediction on a plurality of adjacent prediction blocks collectively.SOLUTION: A merge motion information candidate list generation unit 230 generates a merge motion information candidate list from motion information of a plurality of decoded adjacent blocks adjacent to a prediction block to be decoded, except for a recessive merge motion information candidate, as merge motion information candidates to be used for the prediction block to be decoded. A substitute merge motion information candidate replenishment unit 166, when the recessive merge motion information candidate is detected, adds, to the merge motion information candidate list, motion information of a decoded predetermined adjacent block adjacent to a prediction block different from the prediction block to be decoded in a decoding block as a substitute merge motion information candidate substituting for the recessive merge motion information candidate.

Description

  The present invention relates to a moving picture decoding technique using motion compensated prediction, and more particularly to an image decoding apparatus, an image decoding method, and an image decoding program for decoding motion information used in motion compensated prediction.

  In general video compression coding, motion compensation prediction is used. The motion compensated prediction is performed by dividing the target image into fine blocks, using the decoded image as a reference image, and moving from the processing target block of the target image to the reference block of the reference image based on the amount of motion indicated by the motion vector. This is a technique for generating a signal as a prediction signal. There are two types of motion compensated prediction, one for single prediction using one motion vector and the other for bi-prediction using two motion vectors.

  For a motion vector, a motion vector of an encoded block adjacent to the processing target block is set as a prediction motion vector (also simply referred to as “prediction vector”), and a difference between the motion vector of the processing target block and the prediction vector is obtained. The compression efficiency is improved by transmitting the vector as an encoded vector.

  MPEG-4 AVC / H. In moving picture compression coding such as H.264 (hereinafter referred to as MPEG-4 AVC), motion compensation prediction with high accuracy is made possible by making the block size for motion compensation prediction fine and diverse. On the other hand, there is a problem that the code amount of the encoded vector is increased by reducing the block size.

  Therefore, in MPEG-4 AVC, paying attention to the continuity of motion in the time direction, using the motion vector of the block of the reference image at the same position as the processing target block as the motion vector of the processing target block, Temporal direct motion compensated prediction is used to achieve motion compensated prediction without transmission.

  Also, in Patent Document 1, paying attention to the continuity of motion in the spatial direction, the encoded vector is transmitted using the motion vector of the processed block adjacent to the processing target block as the motion vector of the processing target block. A method for realizing motion compensated prediction without the need is disclosed.

JP-A-10-276439

  In the method described in Patent Document 1, a motion vector included in a processed block adjacent to a processing target prediction block is used as a motion vector of the processing target prediction block, and a plurality of adjacent prediction blocks are moved together. When compensation prediction is performed, parallel motion compensation prediction processing may not be performed.

  The present invention has been made in view of such a situation, and an object of the present invention is to use a plurality of adjacent motion vectors while generating a motion vector of a processed block adjacent to a processing target prediction block for generating a motion vector of the processing target prediction block. It is an object of the present invention to provide a moving picture coding and decoding technique that can realize a parallel processing of motion compensated prediction for performing motion compensated prediction for a plurality of prediction blocks collectively.

  In order to solve the above-described problem, an image decoding device according to an aspect of the present invention is an image decoding device that performs motion compensation prediction by dividing a decoded block into a plurality of prediction blocks based on a division type. A decoding unit (201) that decodes the candidate specific index from a code string in which an index for specifying a candidate in the combined motion information candidate list is encoded as the candidate specific index, a division type of the prediction block to be decoded, and the Based on the position of the prediction block to be decoded in the decoding block, the motion information of a plurality of adjacent blocks that are adjacent to the prediction block to be decoded and decoded in decoding order before the prediction block to be decoded This is the same when motion compensation prediction is performed using a prediction block having a size larger than the size of the prediction block to be decoded. A recessive combined motion information candidate determination unit (165) for detecting a recessive combined motion information candidate having motion information, and a combination motion information candidate for use in the prediction block to be decoded, excluding the recessive combined motion information candidate When a combined motion information candidate list generation unit (230) that generates a combined motion information candidate list from motion information of a plurality of decoded adjacent blocks adjacent to a prediction block to be decoded, and the recessive combined motion information candidate are detected The motion information of a predetermined decoded adjacent block adjacent to a prediction block different from the decoding target prediction block in the decoding block is used as an alternative combined motion information candidate that replaces the recessive combined motion information candidate. An alternative combined motion information candidate supplementing unit (166) to be added to the combined motion information candidate list, and the candidate specifying index Based selects one coupling motion information candidate from the combined motion information candidate list, comprising the coupling motion information selector and (231) to motion information of the prediction block of the decoding target.

  Another aspect of the present invention is an image decoding method. This method is an image decoding method for performing motion compensation prediction by dividing a decoded block into a plurality of prediction blocks based on a division type, and an index for specifying a combined motion information candidate in a combined motion information candidate list is a candidate. Based on the decoding step of decoding the candidate specific index from the code string encoded as the specific index, the division type of the prediction block to be decoded and the position in the decoding block of the prediction block to be decoded, Prediction having a size larger than the size of the prediction block to be decoded among motion information of a plurality of adjacent blocks which are adjacent to the prediction block to be decoded and decoded in decoding order before the prediction block to be decoded Inferiority to detect inferior joint motion information candidates with the same motion information when motion compensation prediction is performed in blocks As a combined motion information candidate for use in the joint motion information candidate determination step and the prediction block to be decoded, a plurality of decoded adjacent blocks adjacent to the prediction block to be decoded excluding the recessive joint motion information candidate are used. A combined motion information candidate list generating step for generating a combined motion information candidate list from motion information, and a prediction block different from the prediction block to be decoded in the decoded block when the recessive combined motion information candidate is detected An alternative combined motion information candidate replenishment step of adding motion information of a predetermined adjacent block that has been decoded adjacent to to the combined motion information candidate list as an alternative combined motion information candidate that replaces the recessive combined motion information candidate; and One combined motion information candidate from the combined motion information candidate list based on the candidate identification index Selected, and a binding motion information selection step of the motion information of the prediction block of the decoding target.

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

  According to the present invention, motion compensation for performing motion compensation prediction on a plurality of adjacent prediction blocks collectively while using a motion vector of a processed block adjacent to the processing target prediction block for generating a motion vector of the processing target prediction block. Predictive parallel processing can be realized with high efficiency.

FIGS. 1A and 1B are diagrams for explaining an encoded block. FIGS. 2A to 2D are diagrams for explaining the prediction block size type. It is a figure explaining a prediction block size type. It is a figure explaining prediction coding mode. It is a figure explaining the relationship between a merge index and a code sequence. It is a figure explaining an example of the syntax of a prediction block. 1 is a diagram illustrating a configuration of a moving image encoding device according to Embodiment 1. FIG. It is a figure which shows the structure of the motion information generation part of FIG. It is a figure explaining the structure of the merge mode determination part of FIG. It is a figure which shows the adjacent block of the prediction block of a process target in case the prediction block size of a process target is 16 pixels x 16 pixels. It is a figure which shows the block in the prediction block on ColPic in the same position as the prediction block of a process target in case the prediction block size of a process target is 16 pixels x 16 pixels, and its peripheral block. It is a figure explaining the structure of the joint motion information candidate list production | generation part of FIG. 10 is a flowchart illustrating an operation of a combined motion information candidate list generation unit in FIG. 9. FIGS. 14A to 14D are diagrams for explaining recessive combined motion information candidates. It is a flowchart explaining the determination process of a recessive joint motion information candidate. It is a flowchart explaining operation | movement of the space joint motion information candidate production | generation part of FIG. It is a flowchart explaining the operation | movement of the alternative joint motion information candidate supplement part of FIG. FIGS. 18A to 18E are diagrams for explaining alternative combined motion information candidates. It is a flowchart explaining operation | movement of the time combination motion information candidate production | generation part of FIG. It is a flowchart explaining the operation | movement of the 1st joint motion information candidate supplement part of FIG. It is a figure explaining the relationship between the frequency | count of combination inspection, combined motion information candidate M, and combined motion information candidate N. It is a flowchart explaining the operation | movement of the 2nd joint motion information candidate supplement part of FIG. 1 is a diagram illustrating a configuration of a video decoding device according to Embodiment 1. FIG. It is a figure which shows the structure of the motion information reproduction | regeneration part of FIG. It is a figure which shows the structure of the joint motion information reproduction | regeneration part of FIG. It is a flowchart explaining operation | movement of an alternative joint motion information candidate supplement part. FIG. 10 is a diagram illustrating a configuration of a combined motion information candidate list generation unit according to Modification 1 of Embodiment 1. The structure of a prediction vector mode determination part is shown. It is a figure explaining the structure of a prediction vector candidate list production | generation part. It is a flowchart explaining operation | movement of a prediction vector candidate list production | generation part. FIGS. 31A to 31E are diagrams for explaining the same CU candidate. It is a flowchart explaining operation | movement of a spatial prediction vector candidate production | generation part. It is a flowchart explaining operation | movement of a spatial scaling prediction vector candidate production | generation part. FIGS. 34A and 34B are diagrams for explaining the same CU candidate as the recessive combined motion information candidate when the prediction block size type is N × N. It is a figure explaining operation | movement of the recessive combined motion information candidate determination part of the modification 2 of Embodiment 2. FIG. FIGS. 36A to 36D are diagrams illustrating alternative combined motion information candidates or alternative prediction vector candidates.

  First, a technique that is a premise of the embodiment of the present invention will be described.

  Currently, apparatuses and systems that comply with an encoding method such as MPEG (Moving Picture Experts Group) are widely used. In such an encoding method, a plurality of images that are continuous on the time axis are handled as digital signal information. At that time, for the purpose of broadcasting, transmitting or storing information with high efficiency, motion compensated prediction using the temporal redundancy by dividing the image into a plurality of blocks and the discrete cosine using the redundancy in the spatial direction Compression encoding is performed using orthogonal transformation such as transformation.

  In 2003, a joint effort between the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) Joint Technical Committee (ISO / IEC) and the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) AVC / H. An encoding method called H.264 (the ISO / IEC has a standard number of 14496-10 and ITU-T has an H.264 standard number, hereinafter referred to as MPEG-4AVC) has been established as an international standard. In MPEG-4 AVC, basically, a median value of motion vectors of a plurality of adjacent blocks of a processing target block is used as a prediction vector. When the prediction block size is not square and the reference index of a specific adjacent block of the processing target block matches the reference index of the processing target block, the motion vector of the specific adjacent block is set as a prediction vector.

  Coding currently called HEVC by the joint work of the International Technical Organization (ISO) and the International Electrotechnical Commission (IEC) Joint Technical Committee (ISO / IEC) and the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Standardization of the method is being studied.

  In the standardization of HEVC, a plurality of adjacent blocks and another decoded image block are used as a candidate block group, and one candidate block is selected from these candidate block groups, and information on the selected candidate block is encoded and decoded. A merge mode is being considered.

[Embodiment 1]
(Encoding block)
In the present embodiment, the input image signal is divided into units of maximum encoding blocks, and the divided maximum encoding blocks are processed in a raster scan order. The encoded block has a hierarchical structure, and can be made smaller encoded blocks by sequentially equally dividing into 4 in consideration of the encoding efficiency. Note that the encoded blocks divided into four are encoded in the zigzag scan order. An encoded block that cannot be further reduced is called a minimum encoded block. An encoded block is a unit of encoding, and the maximum encoded block is also an encoded block when the number of divisions is zero. In this embodiment, the maximum coding block is 64 pixels × 64 pixels, and the minimum coding block is 8 pixels × 8 pixels.

  FIGS. 1A and 1B are diagrams for explaining an encoded block. In the example of FIG. 1A, the encoded block is divided into ten. CU0, CU1 and CU9 are 32 × 32 pixel coding blocks, CU2, CU3 and CU8 are 16 × 16 pixel coding blocks, and CU4, CU5, CU6 and CU7 are 8 × 8 pixel coding blocks. It has become. In the example of FIG. 1B, the encoded block is divided into one.

(Prediction block)
In the present embodiment, the encoded block is further divided into prediction blocks (also referred to as partitions). The encoded block is divided into one or more prediction blocks according to a prediction block size type (also referred to as “partition type” or partition type). FIGS. 2A to 2D are diagrams for explaining the prediction block size type. 2 (a) is 2N × 2N that does not divide the encoded block, FIG. 2 (b) is 2N × N that is horizontally divided, FIG. 2 (c) is N × 2N that is vertically divided, and FIG. d) shows N × N which is divided into 4 parts horizontally and vertically. 2N × 2N is one prediction block 0, 2N × N and N × 2N are two prediction blocks 0 and 1, and N × N is four prediction blocks 0, prediction block 1, prediction block 2, and prediction It consists of block 3. The prediction block 0, the prediction block 1, the prediction block 2, and the prediction block 3 are encoded in this order.

  FIG. 3 is a diagram for explaining the prediction block size according to the number of divisions of the encoded block and the prediction block size type. The prediction block size in the present embodiment is from 64 pixels × 64 pixels in which the number of CU divisions is 0 and the prediction block size type is 2N × 2N to 3 in the number of CU divisions, and the prediction block size type is N × N. There are 13 predicted block sizes up to 4 pixels x 4 pixels. For example, it can be asymmetrically divided into two horizontally and vertically.

  In the present embodiment, the maximum encoding block is 64 pixels × 64 pixels and the minimum encoding block is 8 pixels × 8 pixels, but the present invention is not limited to this combination. In addition, although the prediction block division pattern is shown in FIGS. 2A to 2D, the combination is not limited to this as long as the combination is divided into one or more.

(Predictive coding mode)
In the present embodiment, the motion compensation prediction and the number of encoded vectors can be switched for each block of the prediction block. Here, an example of a predictive coding mode in which motion compensation prediction is associated with the number of coding vectors will be briefly described with reference to FIG. FIG. 4 is a diagram for explaining the predictive coding mode.

  In the predictive coding mode shown in FIG. 4, the prediction direction of motion compensation prediction is single prediction (L0 prediction) and the number of coding vectors is PredL0, and the prediction direction of motion compensation prediction is single prediction (L1 prediction). PredL1 in which the number of encoding vectors is 1, PredBI in which the prediction direction of motion compensation prediction is bi-prediction (BI prediction) and the number of encoding vectors is 2, and the prediction direction in motion compensation prediction is single prediction ( There is a merge mode (MERGE) which is L0 prediction / L1 prediction) or bi-prediction (BI prediction) and the number of encoding vectors is zero. There is also an intra mode (Intra) which is a predictive coding mode in which motion compensation prediction is not performed. Here, PredL0, PredL1, and PredBI are prediction vector modes.

  In the merge mode, the prediction direction is any of L0 prediction / L1 prediction / BI prediction. This is because the prediction direction of the merge mode takes over the prediction direction of the candidate block selected from the candidate block group as it is, or is decoded information. This is because it is derived from In the merge mode, the encoded vector is not encoded. This is because the merge mode encoding vector inherits the motion vector of the candidate block selected from the candidate block group as it is or is derived from the decoded information.

(Reference index)
In this embodiment, in order to improve the accuracy of motion compensation prediction, it is possible to select an optimal reference image from a plurality of reference images in motion compensation prediction. For this reason, the reference image used in the motion compensation prediction is encoded as a reference image index together with the encoded vector. The reference image index used in motion compensation prediction is a numerical value of 0 or more. If the motion compensation prediction is uni-prediction, one reference index is used, and if the motion compensation prediction is bi-prediction, two reference indexes are used (FIG. 4).

  In merge mode, the reference index is not encoded. This is because the reference index of the merge mode inherits the reference index of the candidate block selected from the candidate block group as it is or is derived from the decoded information.

(Reference index list)
In the present embodiment, a plurality of reference images that can be used in motion compensation prediction are registered in the reference index list, and the reference image is confirmed by indicating the reference image registered in the reference index list by the reference index. Used in motion compensated prediction. The reference index list includes a reference index list L0 and a reference index list L1. When the motion compensation prediction is simple prediction, either L0 prediction using a reference image in the reference index list L0 or L1 prediction using a reference image in the reference index list L1 is used. In the case of bi-prediction, BI prediction using the reference index list L0 and the reference index list L1 is used. The maximum number of reference images that can be registered in each reference index list is 16.

(Merge index)
In the present embodiment, in the merge mode, a plurality of adjacent blocks in the processing target image and blocks around the same position as the processing target block in another encoded image are used as candidate block groups. A candidate block having the optimal predictive coding mode, motion vector, and reference index is selected from the block group, and a merge index for indicating the selected candidate block is encoded and decoded. Only one merge index is used in the merge mode (FIG. 4). The maximum number of merge indexes (also referred to as the maximum number of merge candidates) is 5, and the merge index is an integer from 0 to 4. Here, the maximum number of merge indexes is set to 5, but it may be 2 or more, and is not limited to this.

  Hereinafter, the motion information of the candidate block that is the target of the merge index is referred to as a combined motion information candidate, and the aggregate of combined motion information candidates is referred to as a combined motion information candidate list. Hereinafter, the motion information includes a prediction direction, a motion vector, and a reference index.

  The relationship between the merge index and the code string will be described with reference to the drawings. FIG. 5 is a diagram for explaining the relationship between the merge index and the code string. The code string when the merge index is 0 is '0', the code string when the merge index is 1 is '10', the code string when the merge index is 2 is '110', and the code string when the merge index is 3 The code string when the column is “1110” and the merge index is 4 is “11110”, and the code string is set longer as the merge index becomes larger. Therefore, it is possible to improve the encoding efficiency by assigning a small merge index to a candidate block with a high selection rate.

(Predicted vector index)
In the present embodiment, in order to improve the accuracy of the prediction vector, a plurality of adjacent blocks and blocks around the same position as the processing target block of another encoded image are used as candidate block groups, and the candidate block group is used. A candidate block having an optimal motion vector is selected as a prediction vector, and a prediction vector index for indicating the selected candidate block is encoded and decoded. If the motion compensation prediction is uni-prediction, one prediction vector index is used, and if the motion compensation prediction is bi-prediction, two prediction vector indexes are used (FIG. 4). The maximum number of prediction vector indexes (also referred to as the maximum number of prediction vector candidates) is 2, and the prediction vector index is an integer of 0 or 1. Although the maximum number of prediction vector candidates is 2 here, it may be 2 or more, and is not limited to this. Note that the code string of the prediction vector index is “0” when the prediction vector index is 0, and is “1” when the prediction vector index is 1. When the maximum number of prediction vector candidates is 3 or more, a code string is assigned according to the same rule as the merge index.

  Hereinafter, a motion vector of a candidate block that is a target of a prediction vector index is referred to as a prediction vector candidate, and a set of prediction vector candidates is referred to as a prediction vector candidate list.

(Syntax)
An example of the syntax of the prediction block according to the present embodiment will be described with reference to FIG. Whether the prediction block is intra or inter is specified by a higher-order encoding block, and FIG. 6 shows only the syntax of the prediction block when the prediction block is inter. In addition, it is assumed that the prediction block size type is also specified in the encoded block.

  The prediction block (PU of FIG. 6) includes a merge flag (merge_flag), a merge index (merge_idx), an inter prediction type (inter_pred_type), an L0 prediction reference index (ref_idx_10), an L0 prediction difference vector (mvd_10 [0]), mvd_l0 [1]), prediction vector index for L0 prediction (mvp_idx_l0), reference index for L1 prediction (ref_idx_l1), difference vector for L1 prediction (mvd_l1 [0], mvd_l1 [1]), and prediction vector index for L1 prediction ( mvp_idx_l1) is installed. [0] of the difference vector indicates a horizontal component and [1] indicates a vertical component.

  Here, inter_pred_type indicates a prediction direction (also referred to as inter prediction type) of motion compensation prediction, and three types of Pred_L0 (uni prediction of L0 prediction), Pred_L1 (uni prediction of L1 prediction) and Pred_BI (bi prediction of BI prediction). There is. When inter_pred_type is Pred_L0 or Pred_BI, information about L0 prediction is installed, and when inter_pred_type is Pred_L1 or Pred_BI, information about L1 prediction is installed.

  In addition, although the syntax of the prediction block by this Embodiment was set like FIG. 6, it is not limited to this.

  Hereinafter, with reference to the drawings, details of a moving image encoding apparatus, a moving image encoding method, a moving image encoding program, a moving image decoding apparatus, a moving image decoding method, and a moving image decoding program according to a preferred embodiment of the present invention will be described. explain. In the description of the drawings, the same elements are denoted by the same reference numerals and redundant description is omitted.

(Configuration of moving picture coding apparatus 100)
FIG. 7 shows the configuration of moving picture coding apparatus 100 according to the first embodiment. The moving image encoding apparatus 100 is an apparatus that encodes a moving image signal in units of prediction blocks for performing motion compensated prediction. Encoding block division, prediction block size type determination, prediction block size and prediction block position (also referred to as prediction block position information or prediction block number), prediction encoding mode is intra Is determined by a higher-level encoding control unit (not shown), and the first embodiment will explain a case where the predictive encoding mode is not intra. In the first embodiment, a B picture corresponding to bi-prediction will be described, but L1 prediction may be omitted for a P picture not corresponding to bi-prediction.

  The moving image encoding apparatus 100 is realized by hardware such as an information processing apparatus including a CPU (Central Processing Unit), a frame memory, and a hard disk. The moving image encoding apparatus 100 realizes functional components described below by operating the above components. Note that the position information of the prediction block to be processed, the prediction block size, and the prediction direction of motion compensated prediction are assumed to be shared in the video encoding device 100 and are not shown.

  The moving image encoding apparatus 100 according to Embodiment 1 includes a prediction block image acquisition unit 101, a subtraction unit 102, a prediction error encoding unit 103, a code string generation unit 104, a prediction error decoding unit 105, a motion compensation unit 106, and an addition unit. 107, a motion vector detection unit 108, a motion information generation unit 109, a frame memory 110, and a motion information memory 111.

(Function and operation of moving picture coding apparatus 100)
Hereinafter, the function and operation of each unit will be described. The prediction block image acquisition unit 101 acquires the image signal of the prediction block to be processed from the image signal supplied from the terminal 10 based on the position information and the prediction block size of the prediction block, and subtracts the image signal of the prediction block 102, and supplied to the motion vector detection unit 108 and the motion information generation unit 109.

  The motion vector detection unit 108 obtains motion vectors and reference images of the L0 prediction and the L1 prediction from the image signal supplied from the prediction block image acquisition unit 101 and image signals corresponding to a plurality of reference images stored therein. Detect the reference index indicated. The motion vector of the L0 prediction and the L1 prediction and the reference index of the L0 prediction and the L1 prediction are supplied to the motion information generation unit 109. Here, the motion vector detection unit 108 uses image signals corresponding to a plurality of reference images stored therein as reference images, but a reference image stored in the frame memory 110 can also be used.

  A general motion vector detection method calculates an error evaluation value for an image signal of a target image and a prediction signal of a reference image moved by a predetermined movement amount from the same position, and a movement amount that minimizes the error evaluation value. Is a motion vector. When there are a plurality of reference images, a motion vector is detected for each reference image, and a reference image having a minimum error evaluation value is selected. As the error evaluation value, SAD (Sum of Absolute Difference) indicating the sum of absolute differences, MSE (Mean Square Error) indicating the mean square error, or the like can be used. It is also possible to evaluate by adding the motion vector code amount to the error evaluation value.

  The motion information generation unit 109 indicates L0 prediction and L1 prediction motion vectors supplied from the motion vector detection unit 108, reference indexes for L0 prediction and L1 prediction, candidate block groups supplied from the motion information memory 111, and reference indexes. The prediction encoding mode is determined from the reference image in the frame memory 110 and the image signal supplied from the prediction block image acquisition unit 101.

  Based on the determined predictive coding mode, the merge flag, the merge index, the prediction direction of motion compensation prediction, the reference index of L0 prediction and L1 prediction, the difference vector of L0 prediction and L1 prediction, and the prediction vector of L0 prediction and L1 prediction The index is supplied to the code string generation unit 104 as necessary. The motion compensation prediction direction, the reference index of L0 prediction and L1 prediction, and the motion vector of L0 prediction and L1 prediction are supplied to the motion compensation unit 106 and the motion information memory 111. Details of the motion information generation unit 109 will be described later.

  If the prediction direction of the motion compensation prediction supplied from the motion information generation unit 109 is LN prediction, the motion compensation unit 106 stores the frame compensation information in the frame memory 110 indicated by the LN prediction reference index supplied from the motion information generation unit 109. The reference image is motion-compensated based on the LN prediction motion vector supplied from the motion information generation unit 109 to generate a prediction signal for LN prediction. N is 0 or 1. Here, if the prediction direction of motion compensation prediction is bi-prediction, the average value of the prediction signals of L0 prediction and L1 prediction is the prediction signal. Note that the prediction signals of the L0 prediction and the L1 prediction may be weighted. The motion compensation unit 106 supplies the prediction signal to the subtraction unit 102.

  The subtraction unit 102 subtracts the image signal supplied from the prediction block image acquisition unit 101 and the prediction signal supplied from the motion compensation unit 106 to calculate a prediction error signal, and calculates the prediction error signal to the prediction error encoding unit 103. To supply.

  The prediction error encoding unit 103 performs processing such as orthogonal transformation and quantization on the prediction error signal supplied from the subtraction unit 102 to generate prediction error encoded data, and encodes the prediction error encoded data. The data is supplied to the column generation unit 104 and the prediction error decoding unit 105.

  The code string generation unit 104 includes prediction error encoded data supplied from the prediction error encoding unit 103, a merge flag, a merge index, and a motion compensation prediction prediction direction (inter prediction type) supplied from the motion information generation unit 109. , The reference index of L0 prediction and L1 prediction, the difference vector of L0 prediction and L1 prediction, and the prediction vector index of L0 prediction and L1 prediction are entropy-coded according to the syntax sequence shown in FIG. The sequence is supplied to the terminal 11 as an encoded stream. Entropy coding is performed by a method including variable length coding such as arithmetic coding or Huffman coding.

  Also, the code string generation unit 104 encodes the coding block division information, the prediction block size type, the position of the prediction block in the coding block, and the prediction coding mode used in the video coding apparatus 100. SPS (Sequence Parameter Set) that defines parameter groups for determining stream characteristics, PPS (Picture Parameter Set) that defines parameter groups for determining picture characteristics, and parameters for determining slice characteristics Multiplexed in the encoded stream together with slice headers defining groups.

  The prediction error decoding unit 105 performs a process such as inverse quantization or inverse orthogonal transform on the prediction error encoded data supplied from the prediction error encoding unit 103 to generate a prediction error signal, and the prediction error signal Is supplied to the adder 107. The addition unit 107 adds the prediction error signal supplied from the prediction error decoding unit 105 and the prediction signal supplied from the motion compensation unit 106 to generate a decoded image signal, and supplies the decoded image signal to the frame memory 110. To do.

  The frame memory 110 stores the decoded image signal supplied from the adding unit 107. In addition, for a decoded image in which decoding of the entire image is completed, a predetermined number of images of 1 or more is stored as a reference image. The frame memory 110 supplies the stored reference image signal to the motion compensation unit 106 and the motion information generation unit 109. A storage area for storing the reference image is controlled by a FIFO (First In First Out) method.

  The motion information memory 111 stores the motion information supplied from the motion information generation unit 109 for a predetermined number of images in units of the minimum predicted block size. The motion information of the adjacent block of the prediction block to be processed is set as a space candidate block group.

  In addition, the motion information memory 111 sets the motion information of the block on the ColPic located in the same position as the prediction block to be processed and its neighboring blocks as a time candidate block group. The motion information memory 111 supplies the spatial candidate block group and the temporal candidate block group to the motion information generation unit 109 as candidate block groups. The motion information memory 111 is synchronized with the frame memory 110 and is controlled by a FIFO (First In First Out) method.

  Here, ColPic is a decoded image different from the prediction block to be processed, and is stored in the frame memory 110 as a reference image. In Embodiment 1, ColPic is a reference image decoded immediately before the processing target image. In Embodiment 1, ColPic is a reference image decoded immediately before the processing target image. However, it may be a decoded image, for example, the reference image immediately before in the display order or the reference image immediately after in the display order. Alternatively, it can be specified in the encoded stream.

  Here, a method for managing motion information in the motion information memory 111 will be described. The motion information is stored in each memory area in units of the smallest prediction block. Each memory area stores at least a prediction direction, a motion vector for L0 prediction, a reference index for L0 prediction, a motion vector for L1 prediction, and a reference index for L1 prediction.

  When the predictive coding mode is the intra mode, (0, 0) is stored as a motion vector for L0 prediction and L1 prediction, and “−1” is stored as a reference index for L0 prediction and L prediction. Hereinafter, in the motion vector (H, V), H represents a horizontal component and V represents a vertical component. The reference index “−1” may be any value as long as it can be determined that the mode in which motion compensation prediction is not performed. From this point onward, unless expressed otherwise, the term “block” refers to the smallest predicted block unit when expressed simply as a block. Also, in the case of a block outside the area, (0, 0) is stored as a motion vector for L0 prediction and L1 prediction, and “−1” is stored as a reference index for L0 prediction and L1 prediction, as in the intra mode. The When the LX direction (X is 0 or 1) is valid, the reference index in the LX direction is 0 or more, and when the LX direction is invalid (not valid), the reference index in the LX direction is “−1”. It is to be.

(Configuration of the motion information generation unit 109)
Next, a detailed configuration of the motion information generation unit 109 will be described. FIG. 8 shows a configuration of the motion information generation unit 109. The motion information generation unit 109 includes a prediction vector mode determination unit 120, a merge mode determination unit 121, and a prediction encoding mode determination unit 122. The terminal 12 is in the motion information memory 111, the terminal 13 is in the motion vector detection unit 108, the terminal 14 is in the frame memory 110, the terminal 15 is in the prediction block image acquisition unit 101, the terminal 16 is in the code string generation unit 104, and the terminal 50 Are connected to the motion compensation unit 106, and the terminal 51 is connected to the motion information memory 111, respectively.

(Function and operation of motion information generation unit 109)
Hereinafter, the function and operation of each unit will be described. The prediction vector mode determination unit 120 includes a candidate block group supplied from the terminal 12, a motion vector for L0 prediction and L1 prediction supplied from the terminal 13, a reference index for L0 prediction and L1 prediction, and a reference index supplied from the terminal 14. The inter-prediction type is determined from the reference image shown in FIG. 5 and the image signal supplied from the terminal 15, and the prediction vector index of the L0 prediction and the L1 prediction is selected according to the inter prediction type, and the difference vector between the L0 prediction and the L1 prediction is selected. , A prediction error is calculated, and a rate distortion evaluation value is calculated. Then, motion information, a difference vector, a prediction vector index, and a rate distortion evaluation value based on the inter prediction type are supplied to the prediction coding mode determination unit 122.

  The merge mode determination unit 121 generates a combined motion information candidate list from the candidate block group supplied from the terminal 12, the reference image supplied from the terminal 14, and the image signal supplied from the terminal 15, and the combined motion information One merged motion information candidate is selected from the candidate list, a merge index is determined, and a rate distortion evaluation value is calculated. Then, the motion information of the combined motion information candidate, the merge index, and the rate distortion evaluation value are supplied to the predictive coding mode determination unit 122. Details of the merge mode determination unit 121 will be described later.

  The prediction coding mode determination unit 122 compares the rate distortion evaluation value supplied from the prediction vector mode determination unit 120 and the rate distortion evaluation value supplied from the merge mode determination unit 121 to determine a merge flag.

  If the predicted vector mode rate distortion evaluation value is less than the merge mode rate distortion evaluation value, the merge flag is set to “0”. The prediction encoding mode determination unit 122 supplies the merge flag, the inter prediction type, the reference index, the difference vector, and the prediction vector index supplied from the prediction vector mode determination unit 120 to the terminal 16, and the prediction vector mode determination unit 120 The supplied motion information is supplied to the terminal 50 and the terminal 51.

  If the merge mode rate distortion evaluation value is less than or equal to the predicted vector mode rate distortion evaluation value, the merge flag is set to “1”. The predictive coding mode determination unit 122 supplies the merge flag and the merge index supplied from the merge mode determination unit 121 to the terminal 16, and supplies the motion information supplied from the merge mode determination unit 121 to the terminal 50 and the terminal 51. To do. Although a specific calculation method of the rate distortion evaluation value is not the main point of the present invention, detailed description is omitted, but the prediction error amount per code amount is calculated from the prediction error and the code amount, and the rate distortion evaluation value is calculated. The evaluation value has a characteristic that the encoding efficiency increases as the value decreases. Therefore, encoding efficiency can be improved by selecting a predictive encoding mode with a small rate distortion evaluation value.

(Configuration of merge mode determination unit 121)
Next, a detailed configuration of the merge mode determination unit 121 will be described. FIG. 9 is a diagram for explaining the configuration of the merge mode determination unit 121. The merge mode determination unit 121 includes a combined motion information candidate list generation unit 140 and a combined motion information selection unit 141. The combined motion information candidate list generation unit 140 is also installed in the video decoding device 200 that decodes the code sequence generated by the video encoding device 100 according to Embodiment 1 in the same manner. The moving image decoding apparatus 200 generates the same combined motion information list.

(Function and operation of merge mode determination unit 121)
Hereinafter, the function and operation of each unit will be described. The combined motion information candidate list generation unit 140 generates a combined motion information candidate list including the maximum number of merge candidate motion candidates from the candidate block group supplied from the terminal 12, and uses the combined motion information candidate list as the combined motion information. This is supplied to the selection unit 141. A detailed configuration of the combined motion information candidate list generation unit 140 will be described later.

  The combined motion information selection unit 141 selects the optimum combined motion information candidate from the combined motion information candidate list supplied from the combined motion information candidate list generation unit 140, and is information indicating the selected combined motion information candidate. A certain merge index is determined and the merge index is supplied to the terminal 17.

  Here, a method for selecting an optimal combined motion information candidate will be described. A prediction error amount is calculated from the reference image supplied from the terminal 14 obtained by motion compensation prediction based on the prediction direction, motion vector, and reference index of the combined motion information candidate, and the image signal supplied from the terminal 15. . A rate distortion evaluation value is calculated from the code amount of the merge index and the prediction error amount, and a combined motion information candidate that minimizes the rate distortion evaluation value is selected as an optimal combined motion information candidate.

(Candidate block group supplied to combined motion information candidate list generation unit 140)
Next, candidate block groups supplied to the combined motion information candidate list generation unit 140 will be described with reference to FIGS. 10 and 11. The candidate block group includes a spatial candidate block group and a temporal candidate block group.

  FIG. 10 shows adjacent blocks of a prediction block to be processed when the prediction block size to be processed is 16 pixels × 16 pixels. In the first embodiment, the space candidate block group is assumed to be five blocks of block A1, block C, block D, block B1, and block E shown in FIG. Here, the spatial candidate block group is five blocks of block A1, block C, block D, block B1, and block E, but the spatial candidate block group is at least one or more processed adjacent to the prediction block to be processed. Any block may be used, and the present invention is not limited to these. For example, all of block A1, block A2, block A3, block A4, block B1, block B2, block B3, block B4, block C, block D, and block E may be spatial candidate blocks.

  Next, the time candidate block group will be described with reference to FIG. FIG. 11 shows a block in a prediction block on ColPic and its peripheral blocks at the same position as the prediction block to be processed when the prediction block size to be processed is 16 pixels × 16 pixels. In the first embodiment, the time candidate block group includes two blocks, block H and block I6 shown in FIG. Here, the time candidate block group is two blocks of block H and block I6 on ColPic, but the time candidate block group is at least one block on a decoded image different from the prediction block to be processed. There is no limitation to these. For example, only the block H may be used. Hereinafter, the block A4 is expressed as a block A, the block B4 is expressed as a block B, the block I6 is expressed as a block I, and the blocks H and I6 are expressed as a time block.

(Configuration of combined motion information candidate list generation unit 140)
Next, a detailed configuration of the combined motion information candidate list generation unit 140 will be described. FIG. 12 is a diagram for explaining the configuration of the combined motion information candidate list generation unit 140. The terminal 19 is connected to the combined motion information selection unit 141. The combined motion information candidate list generating unit 140 includes a spatially combined motion information candidate generating unit 160, a temporally combined motion information candidate generating unit 161, a redundant combined motion information candidate deleting unit 162, a first combined motion information candidate supplementing unit 163, and a second A combined motion information candidate supplementing unit 164 is included. Here, the spatially combined motion information candidate generating unit 160 includes a recessive combined motion information candidate determining unit 165 and an alternative combined motion information candidate supplementing unit 166. Hereinafter, it is described that a combined motion information candidate is generated, but it may be paraphrased to be derived.

(Function and operation of combined motion information candidate list generation unit 140)
Hereinafter, the function and operation of each unit will be described. FIG. 13 is a flowchart for explaining the operation of the combined motion information candidate list generation unit 140. First, the combined motion information candidate list generation unit 140 initializes a combined motion information candidate list (S100). There are no combined motion information candidates in the initialized combined motion information candidate list.

  Next, the spatially coupled motion information candidate generation unit 160 generates the maximum number of spatially coupled motion information candidates from 0 candidate block groups supplied from the terminal 12 and adds them to the combined motion information candidate list. (S101). Next, the alternative combined motion information candidate supplementing unit 166 installed in the spatial combined motion information candidate generation unit 160 adds an alternative combined motion information candidate to replace the recessive combined motion information candidate to the combined motion information candidate list ( In step S <b> 102, the combined motion information candidate list and the candidate block group are supplied to the time combined motion information candidate generation unit 161. The detailed operation of the spatially coupled motion information candidate generation unit 160 will be described later. Further, the recessive combined motion information candidate determination unit 165, the alternative combined motion information candidate supplement unit 166, and the maximum number of spatially combined motion information candidates will be described later.

  Next, the time combination motion information candidate generation unit 161 generates zero or time combination motion information candidate maximum number of time combination motion information candidates from the candidate block group supplied from the space combination motion information candidate generation unit 160 to generate a space. This is added to the combined motion information candidate list supplied from the combined motion information candidate generation unit 160 (S103), and the combined motion information candidate list is supplied to the redundant combined motion information candidate deletion unit 162. The detailed operation of the time combination motion information candidate generation unit 161 will be described later. Further, the maximum number of temporally combined motion information candidates will be described later.

  Next, the redundant combined motion information candidate deletion unit 162 examines the combined motion information candidates registered in the combined motion information candidate list supplied from the temporal combined motion information candidate generation unit 161, and combines the same motion information. If there are a plurality of motion information candidates, one combined motion information candidate is left and other combined motion information candidates are deleted (S104), and the combined motion information candidate list is supplied to the first combined motion information candidate supplementing unit 163. To do. Accordingly, all of the combined motion information candidates registered in the combined motion information candidate list become different combined motion information candidates.

  Next, the first combined motion information candidate supplementing unit 163 includes 0 to 2 first supplemental combining from the combined motion information candidates registered in the combined motion information candidate list supplied from the redundant combined motion information candidate deleting unit 162. A motion information candidate is generated and added to the combined motion information candidate list (S105), and the combined motion information candidate list is supplied to the second combined motion information candidate supplement unit 164. The detailed operation of the first combined motion information candidate supplement unit 163 will be described later.

  Next, the second combined motion information candidate supplementing unit 164 registers, in the combined motion information candidate list, the second supplemental combined motion information candidate that does not depend on the combined motion information candidate list supplied from the first combined motion information candidate supplementing unit 163. The combined motion information candidates are generated until the maximum number of merge candidates is reached and added to the combined motion information candidate list supplied from the first combined motion information candidate supplementing unit 163 (S106). 19 is supplied. The detailed operation of the second combined motion information candidate supplement unit 164 will be described later.

(Candidate for recessive joint motion information)
Hereinafter, the recessive combined motion information candidates will be described. FIGS. 14A to 14D are diagrams for explaining a recessive combined motion information candidate. It has been mentioned above that an encoded block can be divided into 1 or 2 or 4 prediction blocks. FIG. 14 shows an example in which the encoded block is 16 × 16. By dividing the coding block into a number of prediction blocks, the prediction error related to the coding block can be minimized, while the syntax overhead related to the prediction block shown in FIG. 6 increases by the number of prediction blocks. Therefore, a plurality of prediction blocks having the same motion information and the same prediction error can be combined into one prediction block, and the coding efficiency can be improved by suppressing the number of divisions of the prediction block.

  FIG. 14A is a diagram for explaining an example 1 in which the candidate block A is a recessive combined motion information candidate. The encoded block is the merge mode, and the position of the spatially coupled motion information candidate of the prediction block 1 when the prediction block size type is encoded as N × 2N is shown. Here, if the motion information of the prediction block 0 and the motion information of the prediction block 1 are the same, the prediction block 0 and the prediction block 1 are collectively encoded as 2N × 2N, thereby generating syntax overhead related to the prediction block. And the coding efficiency can be improved. That is, when the prediction block size type is N × 2N and the processing target block is the prediction block 1, the candidate block A corresponding to the candidate block when encoded as 2N × 2N is selected as a combined motion information candidate. Unlikely. Therefore, when the prediction block size type is N × 2N and the processing target block is the prediction block 1, the candidate block A is set as a recessive combined motion information candidate.

  FIG. 14B is a diagram for explaining an example 2 in which the candidate block A is a recessive combined motion information candidate. The encoded block is the merge mode, and the position of the spatially coupled motion information candidate of the prediction block 3 when the prediction block size type is encoded as N × N is shown. If the motion information of the prediction block 0 and the motion information of the prediction block 1 are the same, and the motion information of the prediction block 2 and the motion information of the prediction block 3 are the same, the prediction block 0 and the prediction block 1 are combined. By encoding the prediction block 2 and the prediction block 3 together as 2N × N, it is possible to reduce the syntax overhead related to the prediction block and improve the encoding efficiency. Therefore, when the prediction block size type is N × N and the motion information of the prediction block 0 and the motion information of the prediction block 1 are the same and the prediction block 3, the candidate block A is set as a recessive combined motion information candidate.

  FIG. 14C is a diagram for explaining an example 1 in which the candidate block B is a recessive combined motion information candidate. The coding block is in the merge mode, and the prediction block size type is 2N × N. Here, if the motion information of the prediction block 0 and the motion information of the prediction block 1 are the same, the prediction block 0 and the prediction block 1 are collectively encoded as 2N × 2N, thereby generating syntax overhead related to the prediction block. And the coding efficiency can be improved. Therefore, when the prediction block size type is 2N × N and the processing target block is the prediction block 1, the candidate block B is set as a recessive combined motion information candidate.

  FIG. 14D is a diagram for explaining an example 2 in which the candidate block B is a recessive combined motion information candidate. The encoded block is the merge mode, and the position of the spatially coupled motion information candidate of the prediction block 3 when the prediction block size type is encoded as N × N is shown. Here, if the motion information of the prediction block 0 and the motion information of the prediction block 2 are the same, and the motion information of the prediction block 1 and the motion information of the prediction block 3 are the same, the prediction block 0 and the prediction block 2 are combined. By encoding the prediction block 1 and the prediction block 3 together as N × 2N, it is possible to reduce the syntax overhead related to the prediction block and improve the encoding efficiency. Therefore, when the prediction block size type is N × N and the motion information of the prediction block 0 and the motion information of the prediction block 2 are the same and the prediction block 3, the candidate block B is set as a recessive combined motion information candidate.

  In this way, motion compensation is performed on a prediction block having a size larger than the size of the prediction block to be encoded, based on the division type of the prediction block to be encoded and the position of the prediction block to be encoded in the encoding block. A combined motion information candidate that is more appropriate to be predicted in terms of coding efficiency is selected as a recessive combined motion information candidate. As described above, the recessive combined motion information candidate is a combined motion information candidate that is improved in coding efficiency by being combined with a larger predicted block size. The recessive combined motion information is motion information of a recessive combined motion information candidate.

(Operation of recessive combined motion information candidate determination unit 165)
FIG. 15 is a flowchart for explaining an example of the determination process of the recessive combined motion information candidate determination unit 165.

  First, it is checked whether the prediction block size type is 2N × 2N (S150). If the predicted block size type is 2N × 2N (Y in S150), the process ends. If the predicted block size type is not 2N × 2N (N in S150), the predicted block size type is checked (S151). If the prediction block size type is N × 2N (N × 2N in S151), it is checked whether the prediction block to be processed is the prediction block 1 (S152). If the prediction block size type is 2N × N (2N × N in S151), it is checked whether the prediction block to be processed is the prediction block 1 (S154). If the predicted block size type is N × N (N × N in S151), the process ends. If the prediction block size type is N × 2N and the prediction block to be processed is the prediction block 1 (Y in S152), block A is set as a recessive combined motion information candidate (S153). If the predicted block size type is N × 2N and the predicted block to be processed is not the predicted block 1 (N in S152), the process is terminated. If the prediction block size type is 2N × N and the prediction block to be processed is prediction block 1 (Y in S154), block B is set as a recessive combined motion information candidate (S155). If the predicted block size type is 2N × N and the predicted block to be processed is not the predicted block 1 (N in S154), the process ends.

  FIG. 15 is an example of the determination process of the recessive combined motion information candidate determination unit 165, which is inferior using at least the number of divisions of the encoded block into the prediction block and / or the position of the prediction block in the encoded block. It is only necessary to be able to determine the combined motion information candidate, and the present invention is not limited to this. For example, even when the prediction block type is N × N, if the number of divisions is 4 and the prediction block 3 using the number of divisions of the encoded block into the prediction blocks and the position of the prediction block in the encoded block, And adding a determination process such that both candidate block A and candidate block B are determined as recessive combined motion information candidates, or only one of candidate block A or candidate block B is determined as a recessive combined motion information candidate. You can also.

(Detailed operation of spatially coupled motion information candidate generation unit 160)
Next, a detailed operation of the spatially coupled motion information candidate generation unit 160 will be described. FIG. 16 is a flowchart for explaining the operation of the spatially coupled motion information candidate generation unit 160. First, the replacement flag of each candidate block is initialized to OFF. The spatially coupled motion information candidate generating unit 160 repeatedly performs the following processing in the order of block A, block B, block C, block E, and block D, which are candidate blocks included in the spatial candidate block group of the candidate block group (from S110) S115).

  First, it is checked whether the candidate block is valid (S111). That the candidate block is valid means that at least one of the reference indexes of the L0 prediction and the L1 prediction of the candidate block is 0 or more. If the candidate block is valid (Y in S111), it is checked whether the candidate block is a recessive combined motion information candidate (S112). Here, the recessive combined motion information candidate determination unit 165 operates. If the candidate block is not valid (N in S111), step S112 to step S115 are skipped and the next candidate block is inspected (S116). If the candidate block is a recessive combined motion information candidate (Y in S112), the candidate block replacement flag is turned ON (S113). If the candidate block is not a recessive combined motion information candidate (N in S112), the motion information of the candidate block is added to the combined motion information candidate list as a spatial combined motion information candidate (S114). Following step S114, it is checked whether the number of spatially combined motion information candidates added to the combined motion information candidate list is the maximum number of spatially combined motion information candidates (S115). Here, the maximum number of spatially coupled motion information candidates is 4. If the number of spatially combined motion information candidates added to the combined motion information candidate list is not the maximum number of spatially combined motion information candidates (N in S115), the next candidate block is examined (S115). If the number of spatially combined motion information candidates added to the combined motion information candidate list is the maximum number of spatially combined motion information candidates (Y in S115), the process ends.

  For example, when all of block A, block B, block C, block E, and block D are valid by not registering the recessive combined motion information candidate in the combined motion information candidate list in the spatially combined motion information candidate generation unit 160. , It is possible to register the motion information of block D having a higher selection probability than the recessive combined motion information candidate in the combined motion information candidate list instead of the recessive combined motion information candidate, thereby improving the encoding efficiency. be able to.

  Here, the processing information is processed so that the motion information of block A and block B, which are generally considered to have a long tangent to the processing target block and generally have a high correlation with the processing target block, can be preferentially registered in the combined motion information candidate list. Although the order is block A, block B, block C, block E, and block D, the combined motion information candidates may be registered in the combined motion information candidate list in a highly correlated order, and the present invention is not limited to this. Although the maximum number of spatially coupled motion information candidates is four, the maximum number of spatially coupled motion information candidates may be 1 or more and less than the maximum number of merge candidates, and is not limited thereto.

(Detailed Operation of Alternative Combined Motion Information Candidate Supplementing Unit 166)
Next, a detailed operation of the alternative combined motion information candidate supplement unit 166 will be described. FIG. 17 is a flowchart for explaining the operation of the alternative combined motion information candidate supplementing unit 166. Here, the alternative combined motion information candidate supplementing unit 166 performs the following processing when the number of spatially combined motion information candidates registered in the combined motion information candidate list is not the maximum number of spatially combined motion information candidates. The alternative combined motion information candidate supplementing unit 166 checks whether the replacement flag of the candidate block A is ON (S140). If the replacement flag of candidate block A is ON (Y in S140), the motion information of candidate block X, which is an alternative combined motion information candidate, is added to the end of the combined motion information candidate list (S141), and the process is terminated. . If the replacement flag of candidate block A is not ON (N in S140), it is checked whether the replacement flag of candidate block B is ON (S142). If the replacement flag of candidate block B is ON (Y in S142), the motion information of candidate block Y, which is an alternative combined motion information candidate, is added to the tail of the combined motion information candidate list (S143), and the process ends. . If the replacement flag of the candidate block B is not ON (N in S142), the process is terminated.

  Subsequently, the candidate block X and the candidate block Y will be described. FIGS. 18A to 18E are diagrams for explaining alternative combined motion information candidates. FIG. 18A shows the position of the spatially combined motion information candidate when the prediction block size type is N × 2N and the prediction block is 0. FIG. 18B shows the position of the spatially combined motion information candidate when the prediction block size type is N × 2N, the prediction block 1, and the candidate block A is a recessive combined motion information candidate. Candidate block X is selected from the spatially coupled motion information candidates of prediction block 0. Here, the candidate block A of the prediction block 0 that is in the relationship of the shortest distance that is most likely to be closest to the candidate block A of the prediction block 1 among the candidate blocks of the prediction block 0 is set as the candidate block X. The candidate block A of the prediction block 0 is also the first candidate block that does not overlap with the candidate block of the prediction block 1 in the order of registration in the combined motion information candidate list among the candidate blocks of the prediction block 0. Is a candidate block with a high selection probability.

  FIG. 18C shows the position of the spatially combined motion information candidate when the prediction block size type is 2N × N and the prediction block is 0. FIG. 18D shows the position of the spatially combined motion information candidate when the prediction block size type is 2N × N, the prediction block 1, and the candidate block B is a recessive combined motion information candidate. Candidate block Y is selected from the spatially coupled motion information candidates of prediction block 0. Here, the candidate block B of the prediction block 0 having the shortest distance that is most likely to be closest to the candidate block B of the prediction block 1 among the candidate blocks of the prediction block 0 is set as the candidate block Y. The candidate block B of the prediction block 0 is also the first candidate block that does not overlap with the candidate block of the prediction block 1 in the order of registration in the combined motion information candidate list among the candidate blocks of the prediction block 0. Is a candidate block with a high selection probability. FIG. 18E shows the position of the spatially coupled motion information candidate when the prediction block size type is 2N × 2N.

  Here, the candidate block X is the candidate block A of the prediction block 0. However, the candidate block X and the candidate block Y may be any one of the spatially coupled motion information candidates of the prediction block 0, and are not limited thereto. For example, the candidate block C may be the candidate block C of the prediction block having the highest correlation with the prediction block to be encoded and the prediction block 0 having the shortest distance. Similarly, the candidate block E of the prediction block 0 can be set as the candidate block Y. Note that when the prediction block size is N × 2N, the candidate block A of the prediction block 0 has a relationship that does not overlap with the candidate block of the prediction block size of 2N × 2N, and when the prediction block size is 2N × N, Since candidate block E of block 0 has a relationship that does not overlap with a candidate block having a prediction block size of 2N × 2N, depending on the encoding algorithm, it may be a candidate block that is more effective than other candidate blocks of prediction block 0.

  In addition, in order to reduce the possibility of being deleted by the redundant combined motion information candidate deletion unit 162, the candidate block D and the candidate block E of the prediction block 0 which are candidate blocks far from the encoding target prediction block are selected as candidate blocks. X can also be used. Similarly, candidate block C and candidate block D of prediction block 0 can be set as candidate block Y.

  Here, the alternative combined motion information candidate is added to the end of the combined motion information candidate list, but may be added to another position. For example, an alternative combined motion information candidate can be added at a position where a recessive combined motion information candidate would have been added. If the predicted block size type is N × 2N, the alternative combined motion information candidate is supplemented to the head of the combined motion information candidate list, and if the predicted block size type is 2N × N, the alternative combined motion information candidate is This can be realized by supplementing the head or second of the combined motion information candidate list.

  As described above, by using the spatially combined motion information candidate of the prediction block 0 as the alternative combined motion information candidate of the prediction block 1, the prediction can be performed without increasing the position of the spatially combined motion information candidate in the coding block unit. The encoding efficiency of block 1 can be improved. In addition, since the prediction block 1 does not refer to the prediction block 0, when the coding block is divided into two, the prediction block 0 and the prediction block 1 can be processed in parallel when the coding block is divided into two.

  When the prediction block size is N × N, the prediction block to be encoded is the prediction block 3, the motion information of the prediction block 0 and the motion information of the prediction block 1 are the same, and the motion information and prediction of the prediction block 2 are the same. If the motion information of the block 3 is the same, any of the spatially combined motion information candidates of the prediction block 2 can be used as an alternative combined motion information candidate instead of the candidate block A, and the prediction block to be encoded is the prediction block 3, if the motion information of the prediction block 0 and the motion information of the prediction block 2 are the same, and the motion information of the prediction block 1 and the motion information of the prediction block 3 are the same, the spatial combination of the prediction block 1 instead of the candidate block B Any of the motion information candidates can be used as an alternative combined motion information candidate.

(Detailed operation of time combination motion information candidate generation unit 161)
Subsequently, a detailed operation of the time combination motion information candidate generation unit 161 will be described. FIG. 19 is a flowchart for explaining the operation of the time combination motion information candidate generation unit 161. The following processing is repeated for each prediction direction LX of L0 prediction and L1 prediction (S120 to S127). Here, X is 0 or 1. Further, the following processing is repeated in the order of block H and block I, which are candidate blocks included in the time candidate block group of the candidate block group (S121 to S126).

  The temporal combination motion information candidate generation unit 161 checks whether the LN prediction of the candidate block is valid (S122). Here, N is 0 or 1. Here, N is the same as X. That the LN prediction of the candidate block is valid means that the reference index of the LN prediction of the candidate block is 0 or more. If the LN prediction of the candidate block is valid (Y in S122), the LN prediction motion vector of the candidate block is set as the reference motion vector (S123). If the LN prediction of the candidate block is not valid (N in S122), step 123 to step 126 are skipped and the next candidate block is examined (S126).

  Subsequent to step S123, a reference image for LX prediction of a temporally combined motion information candidate is determined (S124). Here, the reference image of the LX prediction of the temporal combination motion information candidate is a reference image with a reference index of 0. Next, a scaling vector is calculated by scaling the reference motion vector to match the distance between the processing target image and the LX prediction reference image of the temporally combined motion information candidate, and the scaling vector is used for the temporally combined motion information candidate LX prediction. A motion vector is used (S125), and the next prediction direction is processed (S127). Here, the scaling vector calculation formula is the same as the scaling vector calculation formula for temporal direct motion compensated prediction in MPEG-4 AVC. Subsequent to step S127 in which the processing for the L0 prediction and the L1 prediction is completed, it is checked whether at least one of the L0 prediction and the L1 prediction of the temporally coupled motion information candidate is valid (S128). The fact that the LN prediction of the temporally combined motion information candidate is effective means that the reference image for the LN prediction of the temporally combined motion information candidate is determined. If at least one of the L0 prediction and the L1 prediction of the temporally combined motion information candidate is valid (Y in S128), the inter prediction type of the temporally combined motion information candidate is determined, and the temporally combined motion information candidate is combined with the motion. The information is added to the information candidate list (S129). Here, in the determination of the inter prediction type, if only the L0 prediction is valid, the inter prediction type of the temporally combined motion information candidate is Pred_L0, and if only the L1 prediction is valid, the inter prediction type of the temporally combined motion information candidate is Is Pred_L1, and if both the L0 prediction and the L1 prediction are valid, the inter prediction type of the temporally combined motion information candidate is Pred_BI.

  Here, the maximum number of temporally combined motion information candidates that is the maximum number of temporally combined motion information candidates that can be registered in the combined motion information candidate list is 1. Therefore, FIG. 19 omits the processing corresponding to step S115 shown in FIG. 16 which is a flowchart for explaining the operation of the spatially coupled motion information candidate generation unit 160, but the maximum number of temporally coupled motion information candidate candidates is 2 or more. In this case, a process corresponding to step S115 can be added after step S129.

  Here, N is the same as X, but N may be different from X and is not limited to this. In addition, the reference image for the LX prediction of the temporal combination motion information candidate is the reference image of the reference index 0, but is not limited thereto, and is used as a reference image for LX prediction of the candidate blocks included in the spatial candidate block group. The reference image may be determined. Further, although the inter prediction type is any one of Pred_L0, Pred_L1, and Pred_BI, it may be only Pred_BI and is not limited to this.

(Detailed operation of first combined motion information candidate supplementing unit 163)
Next, the detailed operation of the first combined motion information candidate supplement unit 163 will be described. FIG. 20 is a flowchart for explaining the operation of the first combined motion information candidate supplementing unit 163. First, MaxNumGenCand, which is the maximum number for generating the first supplemental combined motion information candidates, from the number of combined motion information candidates (NumCandList) and the maximum number of merge candidates (MaxNumMergeCand) registered in the supplied combined motion information candidate list. Is calculated from Equation 1 (S170).
MaxNumGenCand = MaxNumMergeCand-NumCandList; (NumCandList> 0)
MaxNumGenCand = 0; (NumCandList == 0) Equation 1

  Next, it is checked whether MaxNumGenCand is greater than 0 (S171). If MaxNumGenCand is not greater than 0 (N in S171), the process ends. If MaxNumGenCand is greater than 0 (Y in S171), the following processing is performed. First, loopTimes that is the number of combination inspections is determined. loopTimes is set to NumCandList × NumCandList. However, if loopTimes exceeds 8, loopTimes is limited to 8 (S172). Here, loopTimes is an integer from 0 to 7. The following processing is repeated for loopTimes (S172 to S180). A combination of the combined motion information candidate M and the combined motion information candidate N is determined (S173). Here, the relationship between the number of combination inspections, the combined motion information candidate M, and the combined motion information candidate N will be described. FIG. 21 is a diagram for explaining the relationship between the number of combination inspections, the combined motion information candidate M, and the combined motion information candidate N. As shown in FIG. 21, M and N are different values, and are set in order of decreasing total value of M and N. It is checked whether the L0 prediction of the combined motion information candidate M is valid and the L1 prediction of the combined motion information candidate N is valid (S174). If the L0 prediction of the combined motion information candidate M is valid and the L1 prediction of the combined motion information candidate N is valid (Y in S174), the L0 prediction reference image of the combined motion information candidate M and the motion vector are combined motion information candidates. It is checked whether or not the reference image of the N L1 prediction is different from the motion vector (S175). If the L0 prediction of the combined motion information candidate M is not valid and the L1 prediction of the combined motion information candidate N is not valid (N in S174), the next combination is processed. If the reference image for L0 prediction of the combined motion information candidate M and the reference image for L1 prediction of the combined motion information candidate N are different (Y in S175), the motion vector of the combined motion information candidate M and the reference image for the L0 prediction are combined motion information. By combining the motion vector of L1 prediction of candidate N and the reference image, a bi-join motion information candidate having an inter prediction type of Pred_BI is generated (S176). Here, as the first supplemental combined motion information candidate, bi-coupled motion information is generated by combining the L0 prediction of a certain combined motion information candidate and the L1 prediction motion information of a different combined motion information candidate. If the reference image for L0 prediction of the combined motion information candidate M and the reference image for L1 prediction of the combined motion information candidate N are the same (N in S175), the next combination is processed. Subsequent to step S176, it is checked whether or not there is a combined motion information candidate in the combined motion information candidate list (S177). If the combined motion information candidate does not exist in the combined motion information candidate list (Y of S177), the combined motion information candidate is added to the combined motion information candidate list (S178). If the double coupled motion information candidate exists in the combined motion information candidate list (N in S177), step S178 is skipped. Subsequent to step S177 or step S178, it is checked whether or not the number of generated double coupled motion information is MaxNumGenCand (S179). If the number of generated double coupled motion information is MaxNumGenCand (Y in S179), the process ends. If the number of generated double coupled motion information is not MaxNumGenCand (N in S179), the next combination is processed.

  Here, the first supplemental combined motion information candidate is set as an L0 prediction motion vector of a certain combined motion information candidate registered in the combined motion information candidate list and the reference image, and the L1 prediction motion vector of another combined motion information candidate. In combination with the reference image, a bi-coupled motion information candidate in which the direction of motion compensation prediction is bidirectional is used, but the present invention is not limited to this. For example, combined motion information in which the direction of motion compensated prediction in which an offset value such as +1 is added to the motion vector of L0 prediction and the motion vector of L1 prediction of a certain combined motion information candidate registered in the combined motion information candidate list is bidirectional. Combined motion information in which the direction of motion compensated prediction obtained by adding an offset value such as +1 to the motion vector of L0 prediction or the motion vector of L1 prediction of a certain combined motion information candidate registered in the candidate, combined motion information candidate list is unidirectional Can also be a candidate. As another example of the first supplemental combined motion information candidate, a motion vector of L1 prediction is obtained by scaling based on a motion vector of L0 prediction of a combined motion information candidate registered in the combined motion information candidate list, and these are combined. A new combined motion information candidate in which the direction of motion compensation prediction is bidirectional may be generated. Moreover, you may combine them arbitrarily.

  Here, the first supplemental combined motion information candidate is a combined motion information candidate when there is a slight difference between the motion information of the combined motion information candidate registered in the combined motion information candidate list and the motion information candidate to be processed. By correcting the motion information of the combined motion information candidate registered in the list and generating a new effective combined motion information candidate, the encoding efficiency can be improved.

  As described above, by adding the motion information of alternative combined motion information candidates to the combined motion information candidate list, the motion information of alternative combined motion information candidates can be combined with the motion information of other combined motion information candidates, or Coding efficiency is improved by correcting the motion information of the combined motion information candidate and adding the first supplemental combined motion information candidate having a higher selection rate than the second supplemental combined motion information candidate to the combined motion information candidate list. Can be increased. In particular, in the case of using a bi-join motion information candidate, at least two joint motion information candidates are required. Therefore, when joint motion information candidates other than alternative joint motion information candidates are not registered in the joint motion information candidate list. By adding the motion information of the alternative combined motion information candidate to the combined motion information candidate list, the motion information of the alternative combined motion information candidate is combined with the motion information of other combined motion information candidates, thereby improving the coding efficiency. Can be increased.

(Detailed operation of second combined motion information candidate supplementing unit 164)
Next, the detailed operation of the second combined motion information candidate supplement unit 164 will be described. FIG. 22 is a flowchart for explaining the operation of the second combined motion information candidate supplementing unit 164. First, from the number of combined motion information candidates (NumCandList) registered in the combined motion information candidate list supplied from the first combined motion information candidate supplementing unit 163 and the maximum number of merge candidates (MaxNumMergeCand), the first supplemental combined motion information is obtained. MaxNumGenCand, which is the maximum number of candidates to be generated, is calculated from Equation 2 (S190).
MaxNumGenCand = MaxNumMergeCand-NumCandList; Formula 2

  Next, the following process is repeated MaxNumCand times for i (S191 to S195). Here, i is an integer from 0 to MaxNumGenCand-1. The second supplemental combined motion in which the motion vector for L0 prediction is (0,0), the reference index is i, the motion vector for L1 prediction is (0,0), and the inter prediction type for which the reference index is i is Pred_BI. Information candidates are generated (S192). It is checked whether the second supplementary combined motion information candidate exists in the combined motion information candidate list (S193). If the second supplementary combined motion information candidate does not exist in the combined motion information candidate list (Y in S193), the second supplemental combined motion information candidate is added to the combined motion information candidate list (S194). If the second supplementary combined motion information candidate exists in the combined motion information candidate list (N in S193), the next i is processed (S195).

  Here, the second supplementary combined motion information candidate has a motion vector for L0 prediction of (0, 0), a reference index of i, a motion vector of L1 prediction of (0, 0), and a reference index of i. The combined motion information candidate whose inter prediction type is Pred_BI is used. This is because, in a general moving image, the frequency of occurrence of combined motion information candidates in which the motion vector for L0 prediction and the motion vector for L1 prediction are (0, 0) is statistically high. The present invention is not limited to this as long as it is a combined motion information candidate that is statistically frequently used without depending on the motion information of the combined motion information candidate registered in the combined motion information candidate list. For example, the motion vectors of L0 prediction and L1 prediction may be vector values other than (0, 0), respectively, and may be set so that the reference indexes of L0 prediction and L1 prediction are different. Alternatively, the second supplementary combined motion information candidate can be set as an encoded image or motion information with a high occurrence frequency of a part of the encoded image, encoded in an encoded stream, and transmitted.

  Here, by setting a combined motion information candidate that does not depend on the combined motion information candidate registered in the combined motion information candidate list as the second supplemental combined motion information candidate, the combined motion information candidate registered in the combined motion information candidate list When the number is zero, it is possible to use the merge mode and improve the encoding efficiency. In addition, when the motion information of the combined motion information candidate registered in the combined motion information candidate list and the motion information candidate motion to be processed are different, by generating a new combined motion information candidate and expanding the range of options, Encoding efficiency can be improved.

(Configuration of moving picture decoding apparatus 200)
Next, the moving picture decoding apparatus according to the first embodiment will be described. FIG. 23 is a diagram illustrating a configuration of the video decoding device 200 according to Embodiment 1. The video decoding device 200 is a device that generates a playback image by decoding the code string encoded by the video encoding device 100.

  The moving picture decoding apparatus 200 is realized by hardware such as an information processing apparatus including a CPU (Central Processing Unit), a frame memory, and a hard disk. The moving picture decoding apparatus 200 realizes functional components described below by operating the above components. The coding block division, the prediction block size type determination, the prediction block size and the position of the prediction block in the coding block (position information of the prediction block), and the determination whether the prediction coding mode is intra are not shown. It is assumed that it is determined by the upper control unit, and here, a case where the predictive coding mode is not intra will be described. Note that the position information and the prediction block size of the prediction block to be decoded are shared in the video decoding device 200 and are not shown.

  The moving picture decoding apparatus 200 according to Embodiment 1 includes a code string analysis unit 201, a prediction error decoding unit 202, an addition unit 203, a motion information reproduction unit 204, a motion compensation unit 205, a frame memory 206, and a motion information memory 207.

(Operation of the video decoding device 200)
Hereinafter, the function and operation of each unit will be described. The code string analysis unit 201 analyzes the code string supplied from the terminal 30 to generate prediction error encoded data, a merge flag, a merge index, a motion compensation prediction direction (inter prediction type), a reference index, a difference vector, and Entropy decodes the prediction vector index according to the syntax. Entropy decoding is performed by a method including variable length coding such as arithmetic coding or Huffman coding. Then, the prediction error encoded data is supplied to the prediction error decoding unit 202, and the merge flag, the merge index, the inter prediction type, the reference index, the difference vector, and the prediction vector index are supplied to the motion information reproduction unit 204. To do.

  In addition, the code string analysis unit 201 displays the encoding block division information, the prediction block size type, the position of the prediction block in the encoded block, and the prediction encoding mode used in the video decoding device 200 as an encoded stream. An SPS (Sequence Parameter Set) that defines a parameter group for determining the characteristics of the image, a PPS (Picture Parameter Set) that defines a parameter group for determining the characteristics of the picture, and a parameter group for determining the characteristics of the slice Are decoded from the encoded stream together with the slice header defined in FIG.

  The motion information reproduction unit 204 includes a merge flag, a merge index, an inter prediction type, a reference index, a difference vector, and a prediction vector index supplied from the code string analysis unit 201 and a candidate block group supplied from the motion information memory 207. The motion information is reproduced, and the motion information is supplied to the motion compensation unit 205 and the motion information memory 207. A detailed configuration of the motion information reproducing unit 204 will be described later.

  Based on the motion information supplied from the motion information reproducing unit 204, the motion compensation unit 205 performs motion compensation on the reference image indicated by the reference index in the frame memory 206 based on the motion vector to generate a prediction signal. If the prediction direction is bi-prediction, an average of the prediction signals of the L0 prediction and the L1 prediction is generated as a prediction signal, and the prediction signal is supplied to the adding unit 203.

  The prediction error decoding unit 202 performs a process such as inverse quantization or inverse orthogonal transform on the prediction error encoded data supplied from the code string analysis unit 201 to generate a prediction error signal, and the prediction error signal is It supplies to the addition part 203.

  The adding unit 203 adds the prediction error signal supplied from the prediction error decoding unit 202 and the prediction signal supplied from the motion compensation unit 205 to generate a decoded image signal, and the decoded image signal is stored in the frame memory 206 and Supply to terminal 31.

  The frame memory 206 and the motion information memory 207 have the same functions as the frame memory 110 and the motion information memory 111 of the video encoding device 100. The frame memory 206 stores the decoded image signal supplied from the adding unit 203. The motion information memory 207 stores the motion information supplied from the motion information reproducing unit 204 in units of the minimum predicted block size.

(Detailed configuration of the motion information playback unit 204)
Next, a detailed configuration of the motion information reproducing unit 204 will be described. FIG. 24 shows the configuration of the motion information playback unit 204. The motion information playback unit 204 includes an encoding mode determination unit 210, a motion vector playback unit 211, and a combined motion information playback unit 212. The terminal 32 is connected to the code string analysis unit 201, the terminal 33 is connected to the motion information memory 207, the terminal 34 is connected to the motion compensation unit 205, and the terminal 36 is connected to the motion information memory 207.

(Detailed operation of the motion information playback unit 204)
Hereinafter, the function and operation of each unit will be described. The encoding mode determination unit 210 determines whether the merge flag supplied from the code string analysis unit 201 is “0” or “1”. If the merge flag is “0”, the inter prediction type, reference index, difference vector, and prediction vector index supplied from the code string analysis unit 201 are supplied to the motion vector reproduction unit 211. If the merge flag is “1”, the merge index supplied from the code string analysis unit 201 is supplied to the combined motion information reproduction unit 212.

  The motion vector reproduction unit 211 reproduces a motion vector from the inter prediction type, the reference index, the difference vector, and the prediction vector index supplied from the encoding mode determination unit 210 and the candidate block group supplied from the terminal 33. Motion information is generated and supplied to the terminals 34 and 36.

  The combined motion information reproduction unit 212 reproduces motion information from the merge index supplied from the encoding mode determination unit 210 and the candidate block group supplied from the terminal 33 and supplies the motion information to the terminal 34 and the terminal 36.

(Detailed Configuration of Combined Motion Information Reproducing Unit 212)
Next, a detailed configuration of the combined motion information reproduction unit 212 will be described. FIG. 25 shows the configuration of the combined motion information playback unit 212. The combined motion information reproduction unit 212 includes a combined motion information candidate list generation unit 230 and a combined motion information selection unit 231. The terminal 35 is connected to the encoding mode determination unit 210.

(Detailed operation of the combined motion information reproduction unit 212)
Hereinafter, the function and operation of each unit will be described. The combined motion information candidate list generation unit 230 has the same function as the combined motion information candidate list generation unit 140 of the video encoding device 100, and is the same as the combined motion information candidate list generation unit 140 of the video encoding device 100. The combined motion information candidate list is generated by the operation, and the combined motion information candidate list is supplied to the combined motion information selection unit 231.

  The combined motion information selection unit 231 selects a combined motion information candidate indicated by the merge index supplied from the terminal 35 from the combined motion information candidate list supplied from the combined motion information candidate list generation unit 230 and combines motion The information is determined, and the motion information of the combined motion information is supplied to the terminal 34 and the terminal 36.

  As described above, the moving picture decoding apparatus 200 can generate a reproduction image by decoding the code string encoded by the moving picture encoding apparatus 100.

(Modification 1 of Embodiment 1)
Although the configuration of the combined motion information candidate list generation unit 140 of Embodiment 1 is shown in FIG. 12, the alternative combined motion information candidate supplementing unit 166 may be installed outside the spatial combined motion information candidate generation unit 160. The position of the alternative combined motion information candidate supplementing unit 166 may be as follows. FIG. 27 is a diagram for explaining a configuration of the combined motion information candidate list generation unit 140 according to the first modification of the first embodiment. It differs from the combined motion information candidate list generation unit 140 of Embodiment 1 in that the position of the alternative combined motion information candidate supplementing unit 166 is behind the time combined motion information candidate generation unit 161.

  The operation of the combined motion information candidate list generation unit 140 according to the first modification of the first embodiment replaces step S103 and step S104 in FIG. 13 for explaining the operation of the combined motion information candidate list generation unit 140 according to the first embodiment. Become a thing.

  The alternative combined motion information candidate supplementing unit 166 performs the process in FIG. 17 when the number of spatially combined motion information candidates registered in the combined motion information candidate list is not the maximum number of spatially combined motion information candidates. Same as 1.

  As described above, the position of the alternative combined motion information candidate supplementing unit 166 is placed after the temporal combined motion information candidate generating unit 161, so that the prediction combined block size type is 2N × 2N and the temporal combined motion information candidate generating unit 161 is reached. Can be made the same, the software and hardware can be easily designed, and the circuit scale can be reduced. Also, if the temporally combined motion information has a relatively higher selection rate than the alternative combined motion information candidate, the encoding efficiency can be improved.

  In addition, the recessive combined motion information candidate determination unit 165 may be installed outside the spatial combined motion information candidate generation unit 160. For example, the recessive combined motion information candidate determination unit 165 may be installed at a timing at which the predicted block size type and the position of the predicted block are determined.

  Further, whether or not the recessive combined motion information supplementing unit 166 operates may be transmitted by SPS, PPS, slice header or the like in the encoded stream, and the recessive combined motion information supplementing unit 166 operates only for the B picture. In this way, it is possible to switch and control by picture type.

[Embodiment 2]
The second embodiment will be described below. The configuration and operation of the prediction vector mode determination unit 120 are different from those of the first embodiment. Hereinafter, a detailed configuration of the prediction vector mode determination unit 120 will be described.

(Configuration of Predictive Vector Mode Determination Unit 120)
Subsequently, a detailed configuration of the prediction vector mode determination unit 120 will be described. FIG. 28 shows the configuration of the prediction vector mode determination unit 120. The prediction vector mode determination unit 120 includes a prediction vector candidate list generation unit 130 and a prediction vector determination unit 131. The terminal 17 is connected to the predictive coding mode determination unit 122.

  The prediction vector candidate list generation unit 130 is similarly installed in the motion vector reproduction unit 211 in the video decoding device 200 that decodes the code string generated by the video encoding device 100 according to Embodiment 2. Thus, the motion vector encoding apparatus 100 and the motion picture decoding apparatus 200 generate a prediction vector candidate list having no contradiction.

(Operation of prediction vector mode determination unit 120)
Hereinafter, the operation of the prediction vector mode determination unit 120 will be described.

  First, the following processing is performed for L0 prediction. Hereinafter, X is assumed to be 0. The prediction vector candidate list generation unit 130 acquires a reference index for LX prediction supplied from the terminal 13. A prediction vector candidate list for LX prediction including the maximum number of prediction vector candidates is generated from the candidate block group supplied from the terminal 12 and the reference index for LX prediction. The prediction vector candidate list generation unit 130 supplies the prediction vector candidate list of the LX prediction to the prediction vector determination unit 131.

  The prediction vector determination unit 131 selects one prediction vector candidate as a prediction vector for LX prediction from the prediction vector candidate list for LX prediction supplied from the prediction vector candidate list generation unit 130, and sets a prediction vector index for the LX prediction. decide.

  The prediction vector determination unit 131 subtracts the LX prediction prediction vector from the L0 prediction motion vector supplied from the terminal 13 to calculate an LX prediction difference vector, and the LX prediction difference vector and the LX prediction prediction vector. Output the index.

  The prediction vector determination unit 131 motion-predicted the image signal supplied from the terminal 15 and the reference image supplied from the terminal 14 based on the LX prediction motion vector and the LX prediction reference index supplied from the terminal 13. Pred_LX rate distortion evaluation value is calculated from the prediction error amount from the LX prediction prediction signal, and from the prediction error amount, the L0 prediction difference vector, the LX prediction reference index, and the LX prediction vector index code amount. Is calculated.

  Next, X is set to 1 and the same processing as L0 prediction is performed for L1 prediction.

  Subsequently, the prediction vector determination unit 131 calculates a prediction error amount from the image signal supplied from the terminal 15 and the prediction signal of BI prediction obtained by averaging the prediction signal of L0 prediction and the prediction signal of L1 prediction, and the prediction The rate distortion evaluation value of Pred_BI is calculated from the error amount, the difference vector between the L0 prediction and the L1 prediction, the reference index of the L0 prediction and the L1 prediction, and the code amount of the prediction vector index of the L0 prediction and the L1 prediction.

  The prediction vector determination unit 131 compares the rate distortion evaluation value of Pred_L0, the rate distortion evaluation value of Pred_L1, and the rate distortion evaluation value of Pred_BI, and selects one prediction coding mode that is the minimum rate distortion evaluation value. . Then, motion information, a difference vector, a prediction vector index, and a rate distortion evaluation value based on the prediction coding mode are supplied to the prediction coding mode determination unit 122. If the predictive coding mode is Pred_L0, the motion vector for L1 prediction is (0, 0), the reference index for L1 prediction is “−1”, and if the predictive coding mode is Pred_L1, the motion for L0 prediction. The vector is (0,0), and the reference index for L0 prediction is “−1”.

(Configuration of Predictive Vector Candidate List Generation Unit 130)
Next, a detailed configuration of the prediction vector candidate list generation unit 130 will be described. FIG. 29 is a diagram for explaining the configuration of the prediction vector candidate list generation unit 130. The terminal 18 is connected to the prediction vector determination unit 131. The prediction vector candidate list generation unit 130 includes a spatial prediction vector candidate generation unit 150, a spatial scaling prediction vector candidate generation unit 151, a temporal prediction vector candidate generation unit 152, and a prediction vector candidate supplement unit 153. Here, the spatial prediction vector candidate generation unit 150 and the spatial scaling prediction vector candidate generation unit 151 include an identical CU candidate determination unit 154 and an alternative prediction vector candidate supplement unit 155. Hereinafter, it will be described that a prediction vector candidate is generated, but it may be paraphrased to be derived.

(Operation of prediction vector candidate list generation unit 130)
Hereinafter, the function and operation of each unit will be described. FIG. 30 is a flowchart for explaining the operation of the prediction vector candidate list generation unit 130. First, the prediction vector candidate list generation unit 130 initializes a prediction vector report candidate list (S200). There are no prediction vector candidates in the initialized prediction vector candidate list. The prediction vector candidate list generation unit 130 selects candidate blocks included in the spatial candidate block group supplied from the terminal 12 as a block E and a block A that are the first group, a block C, a block B, and a block D that are the second group. The following processing is repeated in the order of the first group and the second group (S201 to S206).

  The spatial prediction vector candidate generation unit 150 generates zero or one spatial prediction vector candidate for each prediction direction from the candidate block group supplied from the terminal 12, and adds the spatial prediction vector candidate to the prediction vector candidate list ( S202). Next, the alternative prediction vector candidate supplementing unit 155 installed in the spatial prediction vector candidate generation unit 150 generates zero or one alternative prediction vector candidate, and the number of prediction vector candidates registered in the prediction vector candidate list is the same. The alternative prediction vector candidates are added to the prediction vector candidate list so as not to exceed the maximum number of prediction vector candidates (S203), and the prediction vector candidate list and the candidate block group are supplied to the spatial scaling prediction vector candidate generation unit 151. The detailed operation of the spatial prediction vector candidate generation unit 150 will be described later.

  The spatial scaling prediction vector candidate generation unit 151 generates zero or one spatial scaling prediction vector candidate for each prediction direction from the candidate block group supplied from the spatial prediction vector candidate generation unit 150, and is registered in the prediction vector candidate list. The spatial scaling prediction vector candidate is added to the prediction vector candidate list so that the number of prediction vector candidates does not exceed the maximum number of prediction vector candidates (S204). Next, the alternative prediction vector candidate supplementation unit 155 installed in the spatial scaling prediction vector candidate generation unit 151 generates zero or one alternative prediction vector candidate, and the number of prediction vector candidates registered in the prediction vector candidate list. The alternative prediction vector candidate is added to the prediction vector candidate list so that the maximum number of prediction vector candidates does not exceed (S205), and the prediction vector candidate list and the candidate block group are supplied to the temporal prediction vector candidate generation unit 152. Details of the spatial scaling prediction vector candidate generation unit 151 will be described later.

  Next, the temporal prediction vector candidate generation unit 152 generates zero or one temporal prediction vector candidate for each prediction direction from the candidate block group supplied from the spatial scaling prediction vector candidate generation unit 151, and adds it to the prediction vector candidate list. The temporal prediction vector candidate is added to the prediction vector candidate list so that the registered number of prediction vector candidates does not exceed the maximum number of prediction vector candidates (S205), and the prediction vector candidate list and candidate block group are added to the prediction vector candidate supplement unit. 153.

  The prediction vector candidate supplement unit 153 generates a prediction vector supplement candidate, and adds the prediction vector supplement candidate to the prediction vector candidate list so that the number of prediction vector candidates registered in the prediction vector candidate list does not exceed the maximum number of prediction vector candidates. It is added (S206) and supplied to the terminal 18. The prediction vector supplement candidate is a motion vector (0, 0). Here, the motion vector (0, 0) is used as the prediction vector supplement candidate, but a predetermined value such as (1, 1) may be used, and a motion vector in which the horizontal component and the vertical component of the spatial prediction vector candidate are +1 or −1. But you can.

  Here, the candidate blocks included in the spatial candidate block group supplied from the terminal 12 are divided into two groups so that one spatial prediction motion vector candidate can be selected from each group. The spatial prediction motion vector candidates may be selected.

(Same CU candidate)
Hereinafter, the same CU candidate will be described. FIGS. 31A to 31E are diagrams for explaining the same CU candidate. FIG. 31 shows an example in which the encoded block is 16 × 16. FIG. 31A shows an example in which the block A is the same CU candidate when the prediction block size type is N × 2N and the prediction block 1. FIG. 31B shows an example in which the block B is the same CU candidate when the prediction block size type is 2N × N and the prediction block 1. FIG. 31C shows an example in which the block A and the block E are the same CU candidate when the prediction block size type is N × N and the prediction block 1. FIG. 31D shows an example in which the block C and the block D are the same CU candidate when the prediction block size type is N × N and the prediction block 2. FIG. 31E shows an example in which block A, block B, and block C are the same CU candidate when the prediction block size type is N × N and the prediction block 3.

  The same CU candidate when the prediction block size type is N × 2N and the prediction block 1 and when the prediction block size type is 2N × N and the prediction block 1 is the same as the recessive combined motion information candidate of FIG.

(Operation of the same CU candidate determination unit 154)
The operation of the same CU candidate determination unit 154 will be described with reference to FIG. 15 illustrating the operation of the recessive combined motion information candidate determination unit 165. The operation of the recessive combined motion information candidate determination unit 165 is different only in steps S153 and S155. Hereinafter, step S153 and step S155 in the operation of the same CU candidate determination unit 154 will be described. Block A is set as the same CU candidate (S153). Block B is set as the same CU candidate (S155).

  Here, in order to share the determination process, the operation of the same CU candidate determination unit 154 is the same determination process as the operation of the recessive combined motion information candidate determination unit 165, but is not limited thereto. For example, the same determination process as the operation of the recessive combined motion information candidate determination unit 165 may be added when the prediction block type is N × N.

(Detailed operation of spatial prediction vector candidate generation unit 150)
Subsequently, a detailed operation of the spatial prediction vector candidate generation unit 150 will be described. FIG. 32 is a flowchart for explaining the operation of the spatial prediction vector candidate generation unit 150. Hereinafter, the prediction direction of motion compensated prediction of a target for generating a spatial prediction vector candidate will be described as LX (X is 0 or 1). The spatial prediction vector candidate generation unit 150 repeatedly performs the following processing on the first group or the second group of candidate blocks included in the spatial candidate block group supplied from the terminal 12 (S210 to S217).

  It is checked whether the candidate block is in the same encoding block as the processing target block (S211). Here, the same CU candidate determination unit 154 in the spatial prediction vector candidate generation unit 150 operates. If the candidate block is in the same encoded block as the processing target block (Y in S211), the candidate block replacement flag is set to ON (S212), and the next candidate block is inspected (S217). If the candidate block is not in the same encoding block as the processing target block (N in S211), it is checked whether the candidate block is valid (S213). The candidate block is valid when the reference index of the LX prediction of the candidate block is not -1.

  If the candidate block is valid (Y in S213), it is checked whether the reference image indicated by the LX prediction reference index of the candidate block is the same as the reference image indicated by the LX prediction reference index supplied from the terminal 13 (S214). ). If the candidate block is not valid (N in S213), the next candidate block is inspected (S217). If the reference image indicated by the LX prediction reference index of the candidate block and the reference image indicated by the LX prediction reference index supplied from the terminal 13 are the same (Y in S214), the LX prediction motion vector of the candidate block is spatially predicted. A vector candidate is set (S215). If the reference image indicated by the reference index of the LX prediction of the candidate block and the reference image indicated by the reference index of the LX prediction supplied from the terminal 13 are not the same (N in S214), the next candidate block is examined (S217). Following step S215, it is checked whether the number of spatial prediction vector candidates is a predetermined number (S216). Here, the predetermined number is 1. If the number of spatial prediction vector candidates is not a predetermined number (N in S216), the next candidate block is inspected (S217). If the number of spatial prediction vector candidates is a predetermined number (Y in S216), the process ends.

  Here, the target of the spatial prediction vector candidate for LX prediction is the LX prediction motion vector of the candidate block in the same prediction direction, but the reference image indicated by the reference index of the LX prediction of the candidate block and the LX supplied from the terminal 13 It is sufficient that the reference images indicated by the prediction reference indexes are the same. For example, a motion vector in the prediction direction opposite to the candidate block can be used. Here, if the candidate block is in the same encoding block as the processing target block, the replacement flag of the candidate block is set to ON. However, the candidate block is in the same encoding block as the processing target block, and the candidate block If is valid, the replacement flag of the candidate block may be turned ON.

(Detailed Operation of Alternative Prediction Vector Candidate Supplementing Unit 155)
The operation of the alternative prediction vector candidate supplementing unit 155 will be described with reference to FIG. 17 for explaining the operation of the alternative combined motion information candidate supplementing unit 166. The operation of the alternative combined motion information candidate supplementing unit 166 is different only in step S141 and step S143. Hereinafter, step S141 and step S143 in the alternative prediction vector candidate supplement unit 155 will be described. The motion vector of candidate block X, which is an alternative prediction vector candidate, is added to the end of the prediction vector candidate list (S141). The motion vector of candidate block Y, which is an alternative prediction vector candidate, is added to the end of the prediction vector candidate list (S143). The candidate block X and the candidate block Y are assumed to be the same as those described with reference to FIG.

  Here, the alternative prediction vector candidate is added to the tail of the prediction vector candidate list, but may be added to another position. For example, an alternative prediction vector candidate can be added at a position where the same CU candidate would have been added. If the predicted block size type is N × 2N, the alternative combined motion information candidate is supplemented to the head of the combined motion information candidate list, and if the predicted block size type is 2N × N, the alternative combined motion information candidate is This can be realized by supplementing the head or second of the combined motion information candidate list. Further, it is possible not to supplement the prediction vector candidate list with the alternative prediction vector candidates.

  As described above, by using the spatial prediction vector candidate of the prediction block 0 as the alternative prediction vector candidate of the prediction block 1, the position of the spatial prediction vector candidate in the encoded block unit is not increased. Encoding efficiency can be improved. In addition, since the prediction block 1 does not refer to the prediction block 0, the prediction block 0 and the prediction block 1 can be processed in parallel when the encoded block is divided into two.

(Detailed Operation of Spatial Scaling Prediction Vector Candidate Generation Unit 151)
Subsequently, a detailed operation of the spatial scaling prediction vector candidate generation unit 151 will be described. FIG. 33 is a flowchart for explaining the operation of the spatial scaling prediction vector candidate generation unit 151. Hereinafter, the prediction direction of motion compensated prediction for generating a spatial scaling prediction vector candidate will be described as LX (X is 0 or 1). The spatial scaling prediction vector candidate generation unit 151 repeatedly performs the following processing on the first group or the second group of candidate blocks included in the spatial candidate block group supplied from the terminal 12 (S220 to S227).

  It is checked whether the candidate block is in the same encoding block as the processing target block (S221). Here, the same CU candidate determination unit 154 in the spatial scaling prediction vector candidate generation unit 151 operates. If the candidate block is in the same encoding block as the processing target block (Y in S221), the replacement flag of the candidate block is turned ON (S222), and the next candidate block is inspected (S227). If the candidate block is not in the same encoded block as the processing target block (N in S221), it is checked whether the candidate block is valid (S223). The candidate block is valid when the reference index of the LX prediction of the candidate block is not -1.

  If the candidate block is valid (Y in S223), it is checked whether the reference image indicated by the reference index of the LX prediction of the candidate block and the reference image indicated by the reference index of the LX prediction supplied from the terminal 13 are the same (S224). . If the candidate block is not valid (N in S223), the next candidate block is inspected (S227). If the reference image indicated by the reference index of the LX prediction of the candidate block and the reference image indicated by the reference index of the LX prediction supplied from the terminal 13 are not the same (Y in S224), the motion vector of the LX prediction of the candidate block is scaled The scaling vector is set as a spatial scaling prediction vector candidate (S225). The scaling vector is obtained by multiplying the motion vector of the LX prediction of the candidate block by the distance between the processing target image and the reference image indicated by the reference index of the LX prediction supplied from the terminal 13, and the reference index of LX prediction of the processing target image and the candidate block. Is calculated by dividing the distance of the reference image indicated by. If the reference image indicated by the LX prediction reference index of the candidate block is the same as the reference image indicated by the LX prediction reference index supplied from the terminal 13 (N in S224), the next candidate block is examined (S227). Subsequent to step S225, it is checked whether the number of spatial scaling prediction vector candidates is a predetermined number (S226). Here, the predetermined number is 1. If the number of spatial scaling prediction vector candidates is not a predetermined number (N in S226), the next candidate block is examined (S227). If the number of spatial scaling prediction vector candidates is a predetermined number (Y in S226), the process ends.

  Here, although the target of the spatial scaling prediction vector candidate of LX prediction is the LX prediction motion vector of the candidate block in the same prediction direction, the reference image indicated by the LX prediction reference index of the candidate block and the terminal 13 are supplied. The reference images indicated by the reference indexes for LX prediction need not be the same, and for example, a motion vector in the prediction direction opposite to the candidate block can be used. Here, if the candidate block is in the same encoding block as the processing target block, the replacement flag of the candidate block is set to ON. However, the candidate block is in the same encoding block as the processing target block, and the candidate block If is valid, the replacement flag of the candidate block may be turned ON. As described above, in the merge mode, the spatially combined motion information candidate of the prediction block 0 is used as the alternative combined motion information candidate of the prediction block 1, and in the prediction vector mode, the spatial prediction of the prediction block 0 as the alternative prediction vector candidate of the prediction block 1 By using the vector candidates, it is possible to improve the coding efficiency of the prediction block 1 without increasing the position of the spatial prediction vector candidate in the coding block unit. In addition, since the prediction block 1 does not refer to the prediction block 0 in both the merge mode and the prediction vector mode, the encoding block is a case where the encoding block is divided into two and the merge mode and the prediction vector mode are mixed. The prediction block 0 and the prediction block 1 can be processed in parallel.

(Modification 1 of Embodiment 2)
Although the configuration of the prediction vector candidate list generation unit 130 of Embodiment 2 is shown in FIG. 29, the alternative prediction vector candidate supplementation unit 155 is installed outside the spatial prediction vector candidate generation unit 150 and the spatial scaling prediction vector candidate generation unit 151. For example, a single alternative prediction vector candidate supplementing unit 155 may be installed after the spatial scaling prediction vector candidate generation unit 151, or after the temporal prediction vector candidate generation unit 152.

  As described above, by setting the position of the alternative prediction vector candidate supplementing unit 155 outside the spatial scaling prediction vector candidate generating unit 151, the operation is common to the case where the prediction block size type is 2N × 2N. Software and hardware design can be facilitated. Also, if the alternative prediction vector candidate has a relatively low selection rate than other prediction vector candidates, the encoding efficiency can be improved by giving priority to the other prediction vector candidates.

(Modification 2 of Embodiment 2)
In Embodiment 2, the operation of the recessive combined motion information candidate determination unit 165 is shown in FIG. 15, but the recessive combined motion information candidate determination is performed for the case where the prediction block size type in which the number of divided blocks is 4 is N × N. The operation of the unit 165 and the same CU candidate determination unit 154 may be made common, for example, as follows.

(Definition of the same CU candidate as the recessive combined motion information candidate in the case of N × N)
First, the recessive combined motion information candidate and the same CU candidate when the prediction block size type is N × N will be described. Here, the recessive combined motion information candidate and the same CU candidate are defined for the prediction block 1 and the prediction block 3. FIGS. 34A and 34B are diagrams for explaining the recessive combined motion information candidate and the same CU candidate when the prediction block size type is N × N. FIG. 34A shows that the same CU candidate as the recessive combined motion information candidate of the prediction block 1 becomes the prediction block A in the previous prediction block in the coding order. FIG. 34B shows that the same CU candidate as the recessive combined motion information candidate of the prediction block 3 is set as the candidate block A in the prediction block one before in the coding order.

(Operation of recessive combined motion information candidate determination unit 165)
FIG. 35 is a diagram for explaining the operation of the recessive combined motion information candidate determination unit 165 according to the second modification of the second embodiment. The second embodiment is different from the operation of the recessive combined motion information candidate determination unit 165 in that steps S156 and S157 are added. Hereinafter, step S156 and step S157 of the recessive combined motion information candidate determination unit 165 according to the second modification of the second embodiment will be described. It is checked whether the prediction block to be processed is the prediction block 1 or the prediction block 3 (S156). If the prediction block to be processed is the prediction block 1 or the prediction block 3 (Y in S156), the block A is set as a recessive combined motion information candidate (S157). If the prediction block to be processed is not the prediction block 1 or the prediction block 3 (N in S156), the process ends.

(Operation of the same CU candidate determination unit 154)
The operation of the same CU candidate determination unit 154 according to the second modification of the second embodiment will be described with reference to FIG. 35 illustrating the operation of the recessive combined motion information candidate determination unit 165. Step S153, step S155, and step S157 differ from the operation of the recessive combined motion information candidate determination unit 165. Hereinafter, step S153, step S155, and step S157 in the operation of the same CU candidate determination unit 154 according to the second modification of the second embodiment will be described. Block A is set as the same CU candidate (S153). Block B is set as the same CU candidate (S155). Block A is set as the same CU candidate (S157).

(Block X)
Subsequently, the candidate block X used by the alternative combined motion information candidate supplementing unit 166 and the alternative prediction vector candidate supplementing unit 155 will be described. FIGS. 36A to 36D are diagrams for explaining alternative combined motion information candidates or alternative prediction vector candidates.

  FIG. 36A shows the positions of candidate blocks when the prediction block size type is N × N and the prediction block to be processed is the prediction block 0. FIG. 36B shows the positions of candidate blocks when the prediction block size type is N × N and the prediction block to be processed is the prediction block 1. At this time, the candidate block A becomes a recessive combined motion information candidate or the same CU candidate. Candidate block X is selected from candidate blocks of prediction block 0. Here, among the candidate blocks of the prediction block 0, the candidate block A of the prediction block 0 that has the shortest distance from the candidate block A of the prediction block 1 is defined as a block X.

  FIG. 36C shows the positions of candidate blocks when the prediction block size type is N × N and the prediction block to be processed is the prediction block 2. FIG. 36D shows the positions of candidate blocks when the prediction block size type is N × N and the prediction block to be processed is the prediction block 3. At this time, the candidate block A becomes a recessive combined motion information candidate or the same CU candidate. Candidate block X is selected from candidate blocks of prediction block 2. Here, the candidate block A of the prediction block 2 that has the shortest distance from the candidate block A of the prediction block 3 among the candidate blocks of the prediction block 2 is defined as a block X.

  Here, the candidate block X is the prediction block 0 or the prediction block A of the prediction block 2, but the encoding target prediction block having the highest correlation with the encoding target prediction block and the prediction block 0 or the prediction with the shortest distance are used. Candidate block C of block 2 can also be set as candidate block X. Further, in order to reduce the possibility of being deleted by the redundant joint motion information candidate deletion unit 162, the candidate block D or the candidate block of the prediction block 0 or the prediction block 2 which is a candidate block far from the encoding target prediction block E can also be a candidate block X.

  As described above, when the prediction block size type is N × N, in the merge mode, the prediction block 0 and the block that are the previous prediction blocks, respectively, as alternative combined motion information candidates of the prediction block 1 and the prediction block 3 respectively. In the prediction vector mode, candidate blocks in prediction block 0 and prediction block 2 are used as alternative prediction vector candidates for prediction block 1 and prediction block 3, respectively. The coding efficiency of the prediction block 1 and the prediction block 3 can be improved without increasing the block position. Further, in any of the merge mode and the prediction vector mode, the prediction block 1 does not refer to the prediction block 0 and the prediction block 3 does not refer to the prediction block 2, so that the encoded block is divided into four, and the merge mode Even in a coding block in which prediction vector modes coexist, it is possible to process the prediction block 0 and the prediction block 1, and the prediction block 2 and the prediction block 3, respectively, in parallel.

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

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

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

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

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

  DESCRIPTION OF SYMBOLS 100 moving image encoder, 101 prediction block image acquisition part, 102 subtraction part, 103 prediction error encoding part, 104 code stream production | generation part, 105 prediction error decoding part, 106 motion compensation part, 107 addition part, 108 motion vector detection , 109 motion information generation unit, 110 frame memory, 111 motion information memory, 120 prediction vector mode determination unit, 121 merge mode determination unit, 122 prediction coding mode determination unit, 130 prediction vector candidate list generation unit, 131 prediction vector determination 140 combined motion information candidate list generation unit, 141 combined motion information selection unit, 150 spatial prediction vector candidate generation unit, 151 spatial scaling prediction vector candidate generation unit, 152 temporal prediction vector candidate generation unit, 153 prediction vector candidate Mitsuru, 154 Same CU candidate determination unit, 155 Alternative prediction vector candidate supplement unit, 160 Spatial combined motion information candidate generation unit, 161 Temporal combined motion information candidate generation unit, 162 Redundant combined motion information candidate deletion unit, 163 First combined motion Information candidate supplementing unit, 164 second combined motion information candidate supplementing unit, 165 recessive combined motion information candidate determining unit, 166 alternative combined motion information candidate supplementing unit, 200 moving image decoding apparatus, 201 code string analyzing unit, 202 prediction error decoding unit , 203 adder, 204 motion information playback unit, 205 motion compensation unit, 206 frame memory, 207 motion information memory, 210 encoding mode determination unit, 211 motion vector playback unit, 212 joint motion information playback unit, 230 joint motion information candidate A list generation unit, 231 a combined motion information selection unit.

Claims (8)

An image decoding apparatus that performs motion compensation prediction by dividing a decoded block into a plurality of prediction blocks based on a division type,
A decoding unit that decodes the candidate specific index from a code string in which an index for specifying a combined motion information candidate in the combined motion information candidate list is encoded as a candidate specific index;
Based on the division type of the prediction block to be decoded and the position of the prediction block to be decoded in the decoding block, the prediction block adjacent to the prediction block to be decoded is preceded by the prediction block to be decoded in decoding order. Inferiority of detecting a recessive joint motion information candidate having the same motion information when motion compensation prediction is performed with a prediction block having a size larger than the size of the prediction block to be decoded, from among motion information of a plurality of adjacent blocks to be decoded A combined motion information candidate determination unit;
As a combined motion information candidate for use in the prediction block to be decoded, a combined motion information candidate list from motion information of a plurality of decoded adjacent blocks adjacent to the prediction block to be decoded excluding the recessive combined motion information candidate A combined motion information candidate list generation unit for generating
When the recessive combined motion information candidate is detected, motion information of a predetermined decoded adjacent block adjacent to a prediction block different from the prediction block to be decoded in the decoded block is represented by the recessive combined motion information. An alternative combined motion information candidate supplementing unit to add to the combined motion information candidate list as an alternative combined motion information candidate to replace the candidate;
An image decoding comprising: a combined motion information selection unit that selects one combined motion information candidate from the combined motion information candidate list based on the candidate identification index and uses the combined motion information candidate as motion information of the prediction block to be decoded. apparatus.   The alternative combined motion information candidate supplementing unit is the shortest distance from a block having the recessive combined motion information candidate among decoded adjacent blocks adjacent to a prediction block different from the prediction block to be decoded in the decoded block. 2. The image decoding apparatus according to claim 1, wherein a certain block is set as the predetermined adjacent block.   The alternative combined motion information candidate supplementation unit is a decoded adjacent block adjacent to a prediction block different from the decoding target prediction block in the decoding block, and has a shortest distance from the decoding target prediction block. The image decoding device according to claim 1, wherein the predetermined adjacent block is used.   The alternative combined motion information candidate supplementing unit is configured to make the code length longer than the candidate specific index of the combined motion information candidate that is not the alternative combined motion information candidate. 4. The image decoding apparatus according to claim 1, wherein a combined motion information candidate is added to the combined motion information candidate list. 5.   The alternative combined motion information candidate supplementing unit adds the alternative combined motion information candidate to the first or second of the combined motion information candidate list according to the division type of the prediction block to be decoded. The image decoding device according to any one of claims 1 to 3.   Using the combined motion information candidate included in the combined motion information candidate list, a new combined motion information candidate is generated and added to the combined motion information candidate list. The image decoding apparatus according to claim 1, further comprising a subsequent stage. An image decoding method for performing motion compensation prediction by dividing a decoded block into a plurality of prediction blocks based on a division type,
A decoding step of decoding the candidate specific index from a code string in which an index for specifying a combined motion information candidate in the combined motion information candidate list is encoded as a candidate specific index;
Based on the division type of the prediction block to be decoded and the position of the prediction block to be decoded in the decoding block, the prediction block adjacent to the prediction block to be decoded is preceded by the prediction block to be decoded in decoding order. Inferiority of detecting a recessive joint motion information candidate having the same motion information when motion compensation prediction is performed with a prediction block having a size larger than the size of the prediction block to be decoded, from among motion information of a plurality of adjacent blocks to be decoded A combined motion information candidate determination step;
As a combined motion information candidate for use in the prediction block to be decoded, a combined motion information candidate list from motion information of a plurality of decoded adjacent blocks adjacent to the prediction block to be decoded excluding the recessive combined motion information candidate A combined motion information candidate list generation step for generating
When the recessive combined motion information candidate is detected, motion information of a predetermined decoded adjacent block adjacent to a prediction block different from the prediction block to be decoded in the decoded block is represented by the recessive combined motion information. An alternative combined motion information candidate replenishment step of adding to the combined motion information candidate list as an alternative combined motion information candidate instead of a candidate;
And a combined motion information selection step of selecting one combined motion information candidate from the combined motion information candidate list based on the candidate identification index and using it as motion information of the prediction block to be decoded. Method. An image decoding program for performing motion compensation prediction by dividing a decoded block into a plurality of prediction blocks based on a division type,
A decoding step of decoding the candidate specific index from a code string in which an index for specifying a combined motion information candidate in the combined motion information candidate list is encoded as a candidate specific index;
Based on the division type of the prediction block to be decoded and the position of the prediction block to be decoded in the decoding block, the prediction block adjacent to the prediction block to be decoded is preceded by the prediction block to be decoded in decoding order. Inferiority of detecting a recessive joint motion information candidate having the same motion information when motion compensation prediction is performed with a prediction block having a size larger than the size of the prediction block to be decoded, from among motion information of a plurality of adjacent blocks to be decoded A combined motion information candidate determination step;
As a combined motion information candidate for use in the prediction block to be decoded, a combined motion information candidate list from motion information of a plurality of decoded adjacent blocks adjacent to the prediction block to be decoded excluding the recessive combined motion information candidate A combined motion information candidate list generation step for generating
When the recessive combined motion information candidate is detected, motion information of a predetermined decoded adjacent block adjacent to a prediction block different from the prediction block to be decoded in the decoded block is represented by the recessive combined motion information. An alternative combined motion information candidate replenishment step of adding to the combined motion information candidate list as an alternative combined motion information candidate instead of a candidate;
Selecting a combined motion information candidate from the combined motion information candidate list based on the candidate identification index, and causing the computer to execute a combined motion information selection step as motion information of the prediction block to be decoded. Image decoding program.

Images