JP5846327B1 - Moving picture decoding apparatus, moving picture decoding method, moving picture decoding program, receiving apparatus, receiving method, and receiving program - Google Patents

Abstract

The prediction accuracy of a motion vector predictor is reduced, and the encoding efficiency is not improved. A combined motion information candidate list construction unit 162 generates a combined motion information candidate list, which is a list of combined motion information candidates, using a spatially combined motion information candidate and a temporally combined motion information candidate. The second combined motion information candidate supplementing unit 165 presets a reference index when the reference index indicates an available reference picture, and a predetermined reference index when the reference index does not indicate an available reference picture. A new combined motion information candidate including a motion vector having a size and direction is generated and added to the combined motion information candidate list. Based on the decoded specific index, the combined motion information selection unit 231 selects one combined motion information candidate from the combined motion information candidate list to which a new combined motion information candidate is added, and the motion of the prediction block to be decoded As information, one selected combined motion information candidate is derived. [Selection] Figure 13

Description

  The present invention relates to a moving image decoding technique using motion compensated prediction, and in particular, a moving image decoding device, a moving image decoding method, a moving image decoding program, a receiving device, and a receiving device that decode motion information used in motion compensated prediction. The present invention relates to a method and a receiving program.

  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 AVC), motion compensation prediction with high accuracy is 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 AVC, focusing on the continuity of motion in the time direction, encoding is performed by scaling the motion vector of the block of the reference image at the same position as the processing target block and using it as the motion vector of the processing target block. Temporal direct motion compensated prediction is used to realize motion compensated prediction without transmitting a vector.

  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

  However, in the method described in AVC and Patent Document 1, since only one prediction vector and one direct mode can be obtained, the prediction accuracy of a motion vector predictor is lowered depending on the image, and the encoding efficiency is not improved. There is also.

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

  The present invention has been made in view of such a situation, and an object of the present invention is to reduce the amount of coding of motion information by setting a plurality of motion information candidates when motion information is not transmitted, thereby improving coding efficiency. An object of the present invention is to provide an improved video decoding technique.

A moving picture decoding apparatus for deriving motion information including a reference index and a motion vector in units of prediction blocks, and specifying for identifying joint motion information candidates to be used for the prediction block to be decoded from a code string A decoding unit that decodes an index, a spatially combined motion information candidate derivation unit that derives spatially combined motion information candidates from motion information of a plurality of decoded prediction blocks that are in the vicinity of the prediction block to be decoded, and the decoding A temporally combined motion information candidate deriving unit for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the target predicted block; and the spatially combined motion information candidate; A combined motion that generates a combined motion information candidate list that is a list of combined motion information candidates using the temporally combined motion information candidates An information candidate list generation unit and a reference index when the reference index indicates an available reference picture, and a predetermined reference index when the reference index does not indicate an available reference picture, are set to a predetermined size. A combined motion information candidate supplementing unit that generates a new combined motion information candidate and includes it in the combined motion information candidate list, and includes the new vector based on the decoded specific index. One combined motion information candidate is selected from the combined motion information candidate list to which the combined motion information candidate is added, and the selected one combined motion information candidate is derived as the motion information of the prediction block to be decoded. A combination motion information selection unit, wherein the predetermined reference index is 0 and the preset motion index is set in advance. Motion vector having a magnitude and provides a video decoding apparatus which is a (0,0).
A moving picture decoding method for deriving motion information including a reference index and a motion vector in units of prediction blocks, and specifying for identifying joint motion information candidates to be used for the prediction block to be decoded from a code string A decoding step of decoding an index, a spatially combined motion information candidate derivation step of deriving a spatially combined motion information candidate from motion information of a plurality of decoded prediction blocks in the vicinity of the prediction block to be decoded, and the decoding A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the target prediction block; and the spatially combined motion information candidates; A combined motion information candidate list that is a list of combined motion information candidates using the temporally combined motion information candidates Generating a combined motion information candidate list, generating a reference index when the reference index indicates an available reference picture, and a predetermined reference index when the reference index does not indicate an available reference picture, Based on the decoded specific index, a combined motion information candidate supplement step of generating a new combined motion information candidate including a motion vector having a preset size and direction and adding the candidate to the combined motion information candidate list Then, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate is added, and the selected one combined motion is used as the motion information of the prediction block to be decoded. A combined motion information selection step for deriving information candidates, DEX is 0, the motion vector having a magnitude that the preset provides a moving picture decoding method which is a (0,0).
A moving picture decoding program for deriving motion information including a reference index and a motion vector in units of prediction blocks, and specifying for identifying joint motion information candidates to be used for the prediction block to be decoded from a code string A decoding step of decoding an index, a spatially combined motion information candidate derivation step of deriving a spatially combined motion information candidate from motion information of a plurality of decoded prediction blocks in the vicinity of the prediction block to be decoded, and the decoding A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the target prediction block; and the spatially combined motion information candidates; Combined motion information candidates that are lists of combined motion information candidates using the temporally combined motion information candidates A combined motion information candidate list generating step for generating a list, a reference index when the reference index indicates an available reference picture, and a predetermined reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplement step for generating a new combined motion information candidate including a motion vector having a preset size and direction and adding it to the combined motion information candidate list; and the decoded specific index Based on the combined motion information candidate list to which the new combined motion information candidate is added, and selects one combined motion information candidate as the motion information of the prediction block to be decoded. A combined motion information selection step for deriving motion information candidates is implemented on a computer. Is allowed, the predetermined the reference index 0, motion vector having a magnitude that the preset provides a moving picture decoding program, which is a (0,0).
A receiving apparatus for deriving motion information including a reference index and a motion vector from a coded sequence in units of prediction blocks, a receiving unit that receives coded data in which a moving image is coded, and the coded data A packet processing unit that performs packet processing to generate the encoded sequence, and a decoding unit that decodes a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code sequence, A spatially coupled motion information candidate derivation unit for deriving a spatially coupled motion information candidate from motion information of a plurality of decoded prediction blocks that are in the vicinity of the prediction block to be decoded; and a picture with the prediction block to be decoded A temporally combined motion information candidate derivation that derives temporally combined motion information candidates from the motion information of the prediction block in a decoded picture different from A combined motion information candidate list generation unit that generates a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidate and the temporally combined motion information candidate, and the reference index A new reference index including a reference index when indicating an available reference picture, and a predetermined reference index when the reference index does not indicate an available reference picture, together with a motion vector having a preset size and direction. A combined motion information candidate supplementing unit that generates a new combined motion information candidate and adds it to the combined motion information candidate list, and the combined motion in which the new combined motion information candidate is added based on the decoded specific index One combined motion information candidate is selected from the information candidate list, and the motion of the prediction block to be decoded is selected. The information includes a combined motion information selection unit for deriving the selected single combined motion information candidate, the predetermined reference index is 0, and the motion vector having the preset size is (0, 0 And a receiving apparatus characterized by the above.
A reception method for deriving motion information including a reference index and a motion vector in units of prediction blocks from an encoded sequence, a reception step of receiving encoded data in which a moving image is encoded, and the encoded data A packet processing step of performing packet processing to generate the encoded sequence; a decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code sequence; A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded; and a picture with the prediction block to be decoded A temporally combined motion information candidate is derived from the motion information of the prediction block in a decoded picture different from A temporally combined motion information candidate derivation step, and a combined motion information candidate list generation step of generating a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidate and the temporally combined motion information candidate. When the reference index indicates an available reference picture, the reference index is set. When the reference index does not indicate an available reference picture, a predetermined reference index has a predetermined size and direction. A combined motion information candidate supplementing step for generating a new combined motion information candidate including the motion vector and adding it to the combined motion information candidate list, and the new combined motion information candidate is based on the decoded specific index. Select one combined motion information candidate from the added combined motion information candidate list A combined motion information selection step for deriving the selected one combined motion information candidate as the motion information of the prediction block to be decoded, wherein the predetermined reference index is 0 and the preset A receiving method is provided in which a motion vector having a magnitude is (0, 0).
A receiving program for deriving motion information including a reference index and a motion vector for each prediction block from a coded sequence, a receiving step for receiving coded data in which a moving image is coded, and the coded data A packet processing step of performing packet processing to generate the encoded sequence; a decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code sequence; A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded; and a picture with the prediction block to be decoded A temporally combined motion information candidate is obtained from the motion information of the predicted block in a decoded picture. A combined motion information candidate list that generates a combined motion information candidate list that is a list of combined motion information candidates by using the temporally combined motion information candidate derivation step to be output, and the spatially combined motion information candidate and the temporally combined motion information candidate. A generation step and a reference index when the reference index indicates an available reference picture, a predetermined reference index when the reference index does not indicate an available reference picture, a preset size and direction, A combined motion information candidate supplement step for generating a new combined motion information candidate and adding it to the combined motion information candidate list, and the new combined motion information based on the decoded specific index One combined motion information candidate from the combined motion information candidate list to which the candidate is added Selecting, as the motion information of the prediction block to be decoded, causing the computer to execute a joint motion information selection step for deriving the selected joint motion information candidate, and the predetermined reference index is 0, A receiving program is provided in which the motion vector having a preset size is (0, 0).

  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, even when motion information is not transmitted, it is possible to reduce the amount of code of motion information by installing a plurality of motion information candidates.

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 flowchart explaining the operation | movement of the production | generation of the reference picture list L0. It is a flowchart explaining the production | generation operation | movement of the reference picture list L1. 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 flowchart explaining operation | movement of a merge mode determination part. It is a figure explaining the structure of the joint motion information candidate list production | generation part of FIG. 12 is a flowchart for explaining the operation of the combined motion information candidate list generation unit in FIG. 11. It is a figure explaining the space candidate block group of a prediction block. It is a flowchart explaining operation | movement of the space joint motion information candidate derivation | leading-out part of FIG. It is a flowchart explaining operation | movement of the time combination motion information candidate derivation | leading-out part of FIG. 14 is a flowchart illustrating an operation of a first combined motion information candidate supplementing unit in FIG. 13. 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. 14 is a flowchart illustrating an operation of a second combined motion information candidate supplementing unit in FIG. 13. It is a figure explaining the relationship between a process target picture and a reference picture. It is a figure explaining an example of a reference picture list. It is a figure explaining an example of the relationship between the reference index of the 2nd supplementary joint motion information candidate by Embodiment 1, and POC. It is a figure which shows the structure of a prediction vector mode determination part. It is a flowchart which shows operation | movement of a prediction vector mode determination part. 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. It is a flowchart explaining operation | movement of a spatial prediction vector candidate derivation | leading-out part. It is a flowchart explaining operation | movement of a spatial scaling prediction vector candidate derivation | leading-out part. It is a flowchart explaining operation | movement of a time prediction vector candidate derivation | leading-out part. 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 figure explaining operation | movement of a joint motion information reproduction part. It is a figure explaining the structure of a motion vector reproduction | regeneration part. It is a figure explaining operation | movement of a motion vector reproduction part. 10 is a flowchart illustrating an operation of a second combined motion information candidate supplementing unit according to the second embodiment. It is a figure explaining an example of the relationship between the reference index of the 2nd supplementary joint motion information candidate according to Embodiment 2 and POC. 22 is a flowchart for explaining the operation of the second combined motion information candidate supplementing unit of the third embodiment. FIG. 25 is a diagram for explaining an example of a relationship between a reference index of a second supplementary combined motion information candidate and a POC according to Embodiment 3.

  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.

  Called AVC in 2003 by the joint work of 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) An encoding system (standard number of 14495-10 for ISO / IEC and H.264 for ITU-T) has been established as an international standard. In 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 HEVC standardization, a plurality of adjacent blocks of a block to be processed and a block of another decoded image are used as candidate blocks, and one candidate block is selected from the candidate block group composed of these candidate block groups and selected. A merge mode in which the information on the candidate block is encoded and decoded, and the motion information on the selected candidate block is used as the motion information on the block to be processed has been studied.
In addition, a plurality of adjacent blocks of the block to be processed and a block of another image that has been decoded are selected as candidate blocks, and one candidate block is selected from the candidate block group configured by these candidate block groups, and the selected candidate is selected. A prediction vector mode in which block information is encoded and decoded and a motion vector of a selected candidate block is used as a prediction vector of a block to be processed has been studied.

[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 encoding block has a hierarchical structure, and can be made into a smaller encoding block by sequentially dividing into four in consideration of encoding efficiency and the like. 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. The 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). An encoded block is divided into one or more prediction blocks according to a prediction block size type (also referred to as a division type or a 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 times of coding block division 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, and the number of CU divisions is 3, and the prediction block size type is N × N. There are 13 predicted block sizes up to 4 pixels x 4 pixels. For example, the coding block 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.

(Picture and slice)
Since pictures and slices are general concepts used in AVC and the like, description thereof is omitted here. In addition, since I pictures, P pictures, B pictures, I slices, P slices, and B slices are also general concepts, description thereof is omitted here. Hereinafter, an image may be called a picture.

(Predictive coding mode)
In the present embodiment, the motion compensation prediction and the number of encoded vectors can be switched for each 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 by a predetermined rule.

(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. The reference index includes a reference index L0 (also referred to as a reference index for L0 prediction) and a reference index L1 (also referred to as a reference index for L1 prediction). If the motion compensated prediction is a uni-prediction, one of the reference index L0 and the reference index L1 is used, and if the motion compensated prediction is a bi-prediction, two reference indexes of the reference index L0 and the reference index L1 are used. Is used (FIG. 4). A Truncated Unary code string, which will be described later, is used as the code string of the reference index.

  In merge mode, the reference index is not encoded. This is because the merge mode reference index is derived from the reference index of the candidate block selected from the candidate block group as it is or according to a predetermined rule.

(Reference picture list)
In the present embodiment, one or more reference images that can be used in motion compensation prediction are registered in a reference picture list, and the reference image registered in the reference picture list is indicated by a reference index to determine the reference image. Used in motion compensated prediction. The reference picture list includes a reference picture list L0 (also referred to as a reference picture list for L0 prediction) and a reference picture list L1 (also referred to as a reference picture list for L1 prediction). When the motion compensation prediction is simple prediction, either L0 prediction using the reference image in the reference picture list L0 or L1 prediction using the reference image in the reference picture list L1 is used. In the case of bi-prediction, BI prediction using the reference picture list L0 and the reference picture list L1 is used.
Note that the reference index L0 indicates a reference image in the reference picture list L0, and the reference index L1 indicates a reference image in the reference picture list L1.

(Merge index)
In the present embodiment, in the merge mode, the same position in the same position prediction block that is at the same position as the plurality of adjacent blocks in the processing target image and the processing target prediction block in another encoded image A merge index for selecting a candidate block having an optimal predictive coding mode, motion vector, and reference index from the candidate block group using blocks around the prediction block as a candidate block group, and indicating the selected candidate block Is encoded and decoded. Only one merge index is used in the merge mode (FIG. 4).
Here, it is assumed that the maximum number of merge indexes (also called the maximum number of merge candidates) is specified by the slice header. The maximum number of merge candidates will be described later. When the maximum number of merge candidates is 5, the merge index is an integer from 0 to 4.

  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.

  Next, the relationship between the merge index and the code string will be described. FIG. 5 is a diagram for explaining the relationship between the merge index and the code string when the maximum number of merge candidates is five. A Truncated Unary code string is used as the code string of the merge index. 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 “1111”, and the code string is set to be shorter as the merge index is smaller. Therefore, it is possible to improve the encoding efficiency by assigning a small merge index to a candidate block with a high selection rate.

  When the maximum number of merge candidates is 4, the code string when the merge index is 0 is' 0 ', the code string when the merge index is 1 is' 10', and the code string when the merge index is 2 is' The code string when the merge index is 3 and 110 is “111”. When the maximum number of merge candidates is 3, the code string when the merge index is 0 is' 0 ', the code string when the merge index is 1 is' 10', and the code string when the merge index is 2 is' 11 '. When the maximum number of merge candidates is 2, the code string when the merge index is 0 is “0”, and the code string when the merge index is 1 is “1”. When the maximum number of merge candidates is 1, a merge index of 0 is not encoded in the encoded stream, and the merge index is implicitly processed as 0 at the time of decoding.

  Next, the relationship between the combined motion information candidate list and the merge index will be described. The merge index 0 indicates the first (0th) combined motion information candidate in the combined motion information candidate list. Hereinafter, the merge index m indicates the m-th combined motion information candidate in the combined motion information candidate list. Here, m is an integer from 0 to (maximum number of merge candidates−1).

(Predicted vector index)
In the present embodiment, in order to improve the accuracy of the prediction vector, the same position in the same position prediction block that is in the same position as the plurality of adjacent blocks in the processing target image and the processing target block of another encoded image A candidate block having an optimal motion vector as a prediction vector is selected from the candidate block group using blocks around the prediction block as a candidate block group, 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.
Next, the relationship between the prediction vector index and the code string will be described. A Truncated Unary code string is used as the code string of the prediction vector index.
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.

  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. The prediction vector index 0 indicates the first (0th) prediction vector candidate in the prediction vector candidate list. Hereinafter, the prediction vector index m indicates the mth prediction vector candidate in the prediction vector candidate list. Here, m is an integer from 0 to (maximum number of prediction vector candidates−1).

(POC)
In the embodiment of the present invention, POC (Picture Order Count) is used as time information (distance information) of an image. POC is a counter indicating the display order of images and is the same as that defined in AVC. Here, when the image display order is increased by 1, the POC is also increased by 1. Therefore, the time difference (distance) between images can be acquired from the POC difference between images.

(Syntax)
An example of the syntax of the prediction block according to the present embodiment will be described. FIG. 6 is a diagram for explaining the syntax according to the present embodiment. FIG. 6 shows an example of the syntax configuration of a PPS (Picture Parameter Set), a slice header (Slice Header), a coding tree (Coding Tree), a coding block (Coding Unit), and a prediction block (Prediction Unit).

  PPS is a parameter set that defines a group of parameters for determining picture characteristics. The PPS includes a predetermined maximum value (num_ref_idx_l0_default_active_minus1) of a reference index of L0 prediction that can be used in the picture, a predetermined maximum value of a reference index of L1 prediction (num_ref_idx_l1_default_active_minus1), and a time candidate use mp (full_g_ent_g_ent_g_ent_g_ent_g_ent_g_______)

  The time candidate use permission flag is a 1-bit code with a value of 0 or 1, and is a flag for restricting the use of a motion vector and a reference index on ColPic. If the time candidate use permission flag is 1, the motion vector and reference index on the ColPic can be used, and if the time candidate use permission flag is 0, the motion vector and the reference index on the ColPic cannot be used. In the present embodiment, the time candidate use permission flag is assumed to be 1.

  The slice header is a header that defines a group of parameters for determining the characteristics of the slice. In the slice header, when the POC and the slice are P slices or B slices, a flag (num_ref_idx_active_override_flag) for changing the maximum value of the reference index that can be used in the slice, the maximum value of the reference index of L0 prediction (num_ref_idx_l0_active_minus1), And the maximum value (num_ref_idx_l1_active_minus1) of the reference index of L1 prediction is set.

  If the flag for changing the maximum value of the reference index is 1, the maximum value (num_ref_idx_10_active_minus1) of the L0 prediction reference index that can be used in the slice is set in the slice header, and the slice is a B slice. The maximum value (num_ref_idx_l1_active_minus1) of the reference index of L1 prediction that can be used in the slice is further installed in the slice header and used.

  If the flag for changing the maximum value of the reference index is 0, the predetermined maximum value of the L0 prediction reference index installed in the PPS is used as the maximum value of the L0 prediction reference index that can be used in the slice, The predetermined maximum value of the L1 prediction reference index installed in the PPS is applied as the maximum value of the L1 prediction reference index that can be used in the slice.

When the slice is a P slice or a B slice, 5_minus_max_num_merge_cands, which is a parameter for determining the maximum number of merge candidates, is set. 5_minus_max_num_merge_cands is a parameter for determining the maximum number of merge candidates, and is an integer from 0 to 4. The maximum number of merge candidates (MaxNumMergeCand) is calculated by subtracting 5_minus_max_num_merge_cands from 5. It is assumed that a Trunked Unary code string is used as the code string of 5_minus_max_num_merge_cands. In this embodiment, 5_minus_max_num_merge_cands is 0 and the maximum number of merge candidates is 5.
In the coding tree, the division information of the coding block is managed. A split_coding_unit_flag is set in the coding tree. If split_coding_unit_flag is 1, the coding tree is divided into four coding trees. If split_coding_unit_flag is 0, the coding tree is a coding block.

  The coding block is provided with a skip mode flag (skip_flag), a prediction mode (pred_mode), and a prediction block size type (part_mode), and one, two, or four according to the skip mode flag and the prediction block size type. Divided into prediction blocks.

  The prediction mode indicates whether it is a coding block that performs intra prediction (intra-screen prediction) or an encoding block that performs inter prediction (motion compensation prediction). When the skip mode flag is 1, the skip mode is set, and the skip mode has one prediction block. The number of divisions of the coding block (coding tree) is also referred to as the depth of the coding block (coding tree).

  The prediction block 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_l0), an L0 prediction difference vector (mvd_l0 [0], mvd_l0 [1]), A prediction vector index for L0 prediction (mvp_idx_l0), a reference index for L1 prediction (ref_idx_l1), a difference vector for L1 prediction (mvd_l1 [0], mvd_l1 [1]), and a prediction vector index for L1 prediction (mvp_idx_l1) are installed. Yes. [0] of the difference vector indicates a horizontal component and [1] indicates a vertical component.

  Here, inter_pred_type indicates the 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. Since inter_pred_type is uniquely Pred_L0 in the P slice, inter_pred_type is omitted.

  In the skip mode, the prediction block is an encoding block that performs inter prediction, and the prediction encoding mode is the merge mode. Therefore, a merge index is set in the skip mode.

  Although the syntax according to the present embodiment is set as shown in FIG. 6, if the encoding block or the prediction block has a plurality of block sizes, the reference mode is used, and the merge mode and the prediction vector mode can be used. Well, 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. Slice type determination, maximum reference index that can be used in a slice, coding block division, skip mode determination, prediction block size type determination, prediction block size and position of prediction block in encoding block (prediction block Determination of whether the prediction encoding mode is intra or not is determined by the encoding control unit 112 outside the moving image encoding device 100 and supplied to the moving image encoding device 100. Is done. The reference picture list is generated by a reference picture list generation unit 113 outside the moving image encoding device 100 and supplied to the moving image encoding device 100. In the first embodiment, a case where the predictive coding mode is not intra will be described. In Embodiment 1, a B picture (B slice) corresponding to bi-prediction will be described unless otherwise specified, but L1 prediction may be omitted for a P picture (P slice) 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 slice type, the reference picture list, the maximum value of the reference index that can be used in the slice, the position information of the prediction block to be processed, the prediction block size, and the prediction direction of motion compensation prediction are shared in the moving picture coding apparatus 100. And 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 together with the POC of the 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. Here, the POC of the reference image is stored in the frame memory 110, but the reference image and the POC need only be uniquely recognized, and the present invention is not limited to this. The POC is not illustrated as being shared by the moving picture coding apparatus 100, the coding control unit 112, and the reference picture list generation unit 113.

  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 uses the motion information of the same position prediction block on the ColPic at the same position as the processing target prediction block 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 an image having a 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 may be the 0th reference image in the reference picture list of L0 prediction or L1 prediction, and 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”. That is.

(Operation of Reference Picture List Generation Unit 113)
Next, the operation of the reference picture list generation unit 113 will be described. The reference picture list generation unit 113 generates a reference picture list according to the slice type supplied from the encoding control unit 112. If the slice type is P slice or B slice, the reference picture list L0 is generated, and if the slice type is B slice, the reference picture list L1 is generated.

  FIG. 8 is a flowchart for explaining the operation of generating the reference picture list L0. The operation of generating the reference picture list L0 will be described with reference to FIG. First, reference pictures having a POC smaller than the POC of the processing target picture are arranged in descending POC order until the number of reference pictures available in the reference picture list L0 (RefPicListL0) is reached (S400). Next, reference pictures having a POC larger than the POC of the processing target picture are arranged in ascending POC order until the number of reference pictures available in the reference picture list L0 (RefPicListL0) is reached (S401). Here, the number of reference pictures that can be used in the reference picture list L0 (RefPicListL0) is a value obtained by adding 1 to the maximum value (num_ref_idx_10_active_minus1) of the reference index of L0 prediction.

  FIG. 9 is a flowchart for explaining the operation of generating the reference picture list L1. The operation of generating the reference picture list L1 will be described with reference to FIG. First, reference pictures having a POC larger than the POC of the processing target picture are arranged in ascending POC order until the number of reference pictures available in the reference picture list L1 (RefPicListL1) is reached (S410). Next, reference pictures having a POC smaller than the POC of the processing target picture are arranged in descending POC order until the number of reference pictures available in the reference picture list L1 (RefPicListL1) is reached (S411). Here, the number of usable reference pictures in the reference picture list L1 (RefPicListL1) is a value obtained by adding 1 to the maximum value (num_ref_idx_l1_active_minus1) of the reference index of L1 prediction.

  As described above, the reference picture list L0 is arranged from the reference pictures that are close to the processing target picture and have a display time before the processing target picture. In the reference picture list L1, reference pictures that are closer to the processing target picture after the display time than the processing target picture are arranged.

  When the number of reference pictures that can be used in the reference picture list L0 (RefPicListL0) is larger than the number of reference pictures whose display time is earlier than the processing target picture, the reference picture list L0 is the same as the reference picture list L1. When there is a reference picture and the number of available reference pictures in the reference picture list L1 (RefPicListL1) is larger than the number of reference pictures whose display time is later than the processing target picture, the reference picture list L1 is a reference picture. It has the same reference picture as list L0. Thereby, bi-prediction is possible from the same reference picture.

(Configuration of the motion information generation unit 109)
Next, a detailed configuration of the motion information generation unit 109 will be described. FIG. 10 shows the 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. Details of the prediction vector mode determination unit 120 will be described later.

  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. 11 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. FIG. 12 is a flowchart for explaining the operation of the merge mode determination unit 121. The combined motion information candidate list generation unit 140 generates a combined motion information candidate list that includes the maximum number of merge candidate motion candidates from the candidate block group supplied from the terminal 12 (S100), and generates the combined motion information candidate list. This is supplied to the combined motion information 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 an optimal combined motion information candidate from the combined motion information candidate list supplied from the combined motion information candidate list generation unit 140 (S101), and selects the selected combined motion information candidate. A merge index, which is information to be indicated, is determined (S102), 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.

(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. 13 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 generation unit 140 includes a spatially combined motion information candidate derivation unit 160, a temporally combined motion information candidate derivation unit 161, a combined motion information candidate list construction unit 162, a redundant combined motion information candidate deletion unit 163, and a first combined motion. An information candidate supplementing unit 164 and a second combined motion information candidate supplementing unit 165 are included.

(Function and operation of combined motion information candidate list generation unit 140)
Hereinafter, the function and operation of each unit will be described. FIG. 14 is a flowchart for explaining the operation of the combined motion information candidate list generation unit 140.

  First, the spatially coupled motion information candidate deriving unit 160 derives the maximum number of spatially coupled motion information candidates from 0 from the spatial candidate block group supplied from the terminal 12 (S110). The motion information candidates are supplied to the combined motion information candidate list construction unit 162. The detailed operation of the spatially coupled motion information candidate derivation unit 160 will be described later. The maximum number of spatially coupled motion information candidates will be described later.

  Next, the combined motion information candidate list generation unit 140 checks whether the time candidate use permission flag (enable_temporal_mvp_flag) is 1 (S111).

  If the time candidate use permission flag is 1 (Y of S111), the time combination motion information candidate derivation unit 161 starts from 0 from the time candidate block group supplied from the terminal 12 and combines the maximum number of time combination motion information candidates. A motion information candidate is derived (S112), and the temporal combined motion information candidate is supplied to the combined motion information candidate list construction unit 162. The detailed operation of the time combination motion information candidate derivation unit 161 will be described later.

  If the time candidate use permission flag is 0 (N in S111), step S112 is skipped.

  Next, the combined motion information candidate list construction unit 162 generates a combined motion information candidate from 0 to the maximum number of spatially combined motion information candidates and from 0 to the maximum number of temporally combined motion information candidates. A list is constructed (S113). Here, it is assumed that the spatially combined motion information candidate and the temporally combined motion information candidate are sequentially registered in the combined motion information candidate list in the derived order.

  Next, the redundant combined motion information candidate deletion unit 163 examines the combined motion information candidates registered in the combined motion information candidate list supplied from the combined motion information candidate list construction unit 162, and combines the same motion information. When there are a plurality of motion information candidates, one combined motion information candidate is left and other combined motion information candidates are deleted (S114), and the combined motion information candidate list is supplied to the first combined motion information candidate supplementing unit 164. To do. Here, the combined motion information candidates registered in the combined motion information candidate list are all different combined motion information candidates.

  Here, the redundant combined motion information candidate deletion unit 163 completely deletes the combined motion information candidate having the same motion information from the combined motion information candidate list, but the first supplemental combined motion information candidate and the second supplemental combined motion information The candidate is not limited to this as long as it is easy to add candidates.

  Next, the first combined motion information candidate supplementing unit 164 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 163. The motion information candidates are derived and added to the combined motion information candidate list so as not to exceed the maximum number of merge candidates (S115), and the combined motion information candidate list is supplied to the second combined motion information candidate supplementing unit 165. When the number of combined motion information candidates registered in the combined motion information candidate list supplied from the redundant combined motion information candidate deletion unit 163 is the maximum number of merge candidates, the redundant combined motion information candidate deletion unit 163 supplies The combined motion information candidate list is supplied to the second combined motion information candidate supplementing unit 165 as it is. The detailed operation of the first combined motion information candidate supplement unit 164 will be described later.

  Next, the second combined motion information candidate supplementing unit 165 has the number of combined motion information candidates registered in the combined motion information candidate list supplied from the first combined motion information candidate supplementing unit 164 not exceeding the maximum number of merge candidates. Thus, the second supplemental combined motion information candidate is derived and added to the combined motion information candidate list (S116), and the combined motion information candidate list is supplied to the terminal 19. If the number of combined motion information candidates registered in the combined motion information candidate list supplied from the first combined motion information candidate supplementing unit 164 is the maximum number of merge candidates, the first combined motion information candidate supplementing unit 164 The supplied combined motion information candidate list is supplied to the terminal 19. The detailed operation of the second combined motion information candidate supplement unit 165 will be described later.

  As described above, the combined motion information candidate list generation unit 140 generates a combined motion information candidate list.

(About blocks)
Hereinafter, candidate block groups of prediction blocks will be described. FIG. 15 is a diagram illustrating a spatial candidate block group of prediction blocks. FIG. 15A shows a space candidate block group having a predicted block size when the size of the encoded block is 16 pixels × 16 pixels and the predicted block size type is 2N × 2N.

  The spatial candidate block group includes a block A positioned to the left of the lower left pixel of the prediction block, a block B positioned above the upper right pixel of the prediction block, a block C positioned diagonally to the upper right of the upper right pixel of the prediction block, It is assumed that the block E is located at the lower left of the prediction block and the block D is located at the upper left of the prediction block.

  There are two time candidate block groups, block H and block I, which are representative blocks in a predetermined area of ColPic. If the position of the upper left pixel of the prediction block to be processed is (x, y) and the width and height of the prediction block to be processed are PUW and PUH, respectively ((((x + PUW) >> 4) << 4) , (((Y + PUH) >> 4) << 4)), a block on ColPic that includes the position of the pixel on the upper left of the block as a time candidate block H. Here, >> is a bit shift in the right direction, and << is a bit shift in the left direction.

  Similarly, a block on ColPic including the position of the pixel at (x + (PUW >> 1), y + (PUH >> 1)) as the position of the upper left pixel of the block is set as a time candidate block I.

  Note that the same positional relationship as that of a prediction block of a coding block having a prediction block size type of 2N × 2N is applied to a prediction block in a coding block whose prediction block size type is not 2N × 2N. FIG. 15B shows a spatial candidate block group when the size of the encoded block is 8 pixels × 8 pixels and the predicted block size type is 2N × N.

  Here, the block A is a block located to the left of the lower left pixel of the prediction block. However, the block A is not limited to this as long as it is in contact with the left side of the prediction block. Further, although the block B is a block located on the upper right pixel of the prediction block, it is sufficient if it is in contact with the upper side of the prediction block, and the present invention is not limited to this. Moreover, although the time candidate block group is two blocks, block H and block I, any block may be used as long as it is within the same position prediction block and around the same position prediction block, and is not limited to this.

(Detailed operation of spatially coupled motion information candidate derivation unit 160)
Next, a detailed operation of the spatially coupled motion information candidate derivation unit 160 will be described. FIG. 16 is a flowchart for explaining the operation of the spatially coupled motion information candidate derivation unit 160. The spatially coupled motion information candidate derivation 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 S120) S124).

  First, it is checked whether the candidate block is valid (S121). 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 S121), the motion information of the candidate block is derived as a spatially combined motion information candidate (S122). If the candidate block is not valid (N in S121), the next candidate block is inspected (S124), and if all candidate blocks have been inspected, the process ends. Following step S122, it is checked whether the derived number of spatially coupled motion information candidates is the maximum number of spatially coupled motion information candidates (S123). If the number of derived spatially coupled motion information candidates is not the maximum number of spatially coupled motion information candidates (N in S123), the next candidate block is examined (S124). If the derived number of spatially coupled motion information candidates is the maximum number of spatially coupled motion information candidates (Y in S123), the process ends. Here, the maximum number of spatially coupled motion information candidates is 4.

(Detailed operation of time combination motion information candidate derivation unit 161)
Next, a detailed operation of the time combination motion information candidate derivation unit 161 will be described. FIG. 17 is a flowchart for explaining the operation of the time combination motion information candidate derivation unit 161. The following processing is repeated for each prediction direction LX of L0 prediction and L1 prediction (S140 to S147). 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 (S141 to S146).

  The temporal combination motion information candidate derivation unit 161 checks whether the LN prediction of the candidate block is valid (S142). 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 of S142), the motion vector of the LN prediction of the candidate block is set as the reference motion vector of the LX prediction (S143). If the LN prediction of the candidate block is not valid (N of S142), the next candidate block is inspected by skipping steps S143 to S145 (S146), and when the inspection of all candidate blocks is completed, the next prediction direction Is processed (S147).

  Subsequent to step S143, a reference image for LX prediction of a temporally combined motion information candidate is determined (S144). Here, the LX prediction reference image of the temporally combined motion information candidate is a reference image with a reference index 0 of LX prediction. Next, the base motion vector is scaled to match the distance between the processing target image and the LX prediction reference image of the temporally combined motion information candidate to calculate an LX predictive motion vector of the temporally combined motion information candidate (S145). The prediction direction is processed (S147). A specific formula for calculating the motion vector of the LX prediction of the temporally combined motion information candidate will be described later.

  Following step S147 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 (S148). If at least one of the L0 prediction and the L1 prediction of the temporal combination motion information candidate is valid (Y in S148), the inter prediction type of the temporal combination motion information candidate is determined to derive the temporal combination motion information candidate (S149). ).

  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.

Next, a formula for calculating a motion vector for LX prediction of temporally combined motion information candidates will be described. The distance between images of ColPic having a temporal candidate block and ColRefLXPic which is a picture to which the temporal candidate block refers in motion compensated prediction of LX prediction is td, the reference image RefLXPic of the LX prediction of the temporal combined motion information candidate and the image of the processing target image CurPic When the inter-distance is tb and the reference motion vector for LX prediction is mvLX, the LX prediction motion vector mvLXCol of the temporally combined motion information candidate is calculated from Equation 1. It can be seen from Equation 1 that subtraction, division, and multiplication for calculating tb and td are required to calculate a motion vector for LX prediction of temporally combined motion information candidates.
mvLXCol = tb / td * mvLX; Equation 1

In order to simplify the floating point arithmetic, an integer arithmetic may be used, for example, by expanding as in Expression 2 to Expression 4. Abs (v) is a function that calculates the absolute value of the value v, Clip3 (uv, lv, v) is a function that limits the value v from the lower limit lv to the upper limit uv, and Sign (v) For example, the function returns 1 when the value v is smaller than 0. >> represents a bit shift in the right direction, and << represents a bit shift in the left direction.
tx = (16384 + Abs (td / 2)) / td; Equation 2
DistScaleFactor = Clip3 (-4096, 4095, (tb * tx + 32) >>6); Equation 3
mvLXCol = Sign (DistScaleFactor * mvLX) * ((Abs (DistScaleFactor * mvLX) + 127) >>8); Equation 4

  Here, the maximum number of temporally combined motion information candidates, which is the maximum number of temporally combined motion information candidates, is set to 1. For this reason, FIG. 17 omits the processing corresponding to step S123 shown in FIG. 17 which is a flowchart for explaining the operation of the spatially coupled motion information candidate deriving 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 S123 can be added after step S149.

  Here, the inter prediction type of temporally coupled motion information candidates is assumed to vary. For example, Pred_BI is always generated by eliminating the dependency relationship between X and N and checking each X in the order of 0 and 1. You may do it.

(Detailed operation of the first combined motion information candidate supplement unit 164)
Next, a detailed operation of the first combined motion information candidate supplement unit 164 will be described. FIG. 18 is a flowchart for explaining the operation of the first combined motion information candidate supplementing unit 164. First, MaxNumGenCand, which is the maximum number for deriving the first supplementary combined motion information candidates, is calculated from the number of combined motion information candidates (NumCandList) registered in the combined motion information candidate list and the maximum number of merge candidates (MaxNumMergeCand) from Equation 5. Calculate (S170).
MaxNumGenCand = MaxNumMergeCand-NumCandList; (NumCandList> 1)
MaxNumGenCand = 0; (NumCandList <= 1) Equation 5

  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. 19 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. 19, 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. A candidate for bi-coupled motion information whose inter prediction type is Pred_BI is derived by combining the motion vector of L1 prediction of candidate N and the reference image (S176). Here, as the first supplementary combined motion information candidate, bi-coupled motion information obtained by combining the motion information of the L1 prediction of a combined motion information candidate different from the L0 prediction of a certain combined motion information candidate is derived. 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, the bi-join motion information candidate is added to the joint motion information candidate list (S178). Subsequent to step S178, it is checked whether or not the number of derived double coupled motion information is MaxNumGenCand (S179). If the number of derived double coupled motion information is MaxNumGenCand (Y in S179), the process is terminated. If the derived number of double coupled motion information is not MaxNumGenCand (N in S179), the next combination is processed (S180). When all combinations have been processed, the process ends.

  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. Here, when NumCandList is 1 or less, the L0 prediction motion vector and reference image of another combined motion information candidate registered in the combined motion information candidate list are used as the L1 prediction motion vector and reference image of another combined motion information candidate. MaxNumGenCand was set to 0 because it cannot be combined with. 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. The candidate may be a combined motion information candidate that is bi-prediction obtained by adding an offset value such as +1 to a motion vector of L0 prediction or a motion vector of L1 prediction of a combined motion information candidate registered in the combined motion information candidate list.

  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. The direction of motion compensation prediction is bidirectional by combining the motion vector and reference image of the L0 prediction of another combined motion information candidate registered in the list with the motion vector and reference image of another combined motion information candidate. Deriving new combined motion information candidates can increase the encoding efficiency.

(Detailed operation of second combined motion information candidate supplementing unit 165)
Next, the detailed operation of the second combined motion information candidate supplement unit 165 will be described. FIG. 20 is a flowchart for explaining the operation of the second combined motion information candidate supplementing unit 165. Here, description will be made assuming that the number of reference pictures that can be used in the reference picture list L0 is equal to or greater than the number of reference pictures that can be used in the reference picture list L1.

First, 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 164, the maximum number of merge candidates (MaxNumMergeCand), and use of the reference picture list L0 From the number of possible reference pictures (num_ref_idx_l0_active_minus1 + 1), MaxNumGenCand, which is the maximum number for deriving the second supplemental combined motion information candidate, is calculated from Equation 6 (S180). Here, Min (x, y) is a function that returns the minimum value of x and y.
MaxNumGenCand = Min (MaxNumMergeCand-NumCandList, num_ref_idx_l0_active_minus1 + 1); Formula 6

Next, the following process is repeated MaxNumCand times for i (S181 to S186). Here, i is an integer from 0 to MaxNumGenCand-1. That is, when 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 164 is smaller than the maximum number of merge candidates (MaxNumMergeCand), at least one The second supplemental combined motion information candidate is derived and added to the combined motion information candidate list. On the other hand, if NumCandList is greater than or equal to MaxNumMergeCand, the second supplemental combined motion information candidate is not derived and is not added to the combined motion information candidate list. In this way, if NumCandList is equal to or greater than MaxNumMergeCand, the second supplemental combined motion information candidate is not added to the combined motion information candidate list, so that a combined motion information candidate list memory larger than MaxNumMergeCand becomes unnecessary.
A second supplementary combined motion information candidate is derived in which the L0 prediction motion vector (mvL0) is (0, 0), the L0 prediction reference index (ref_idx_10) is i, and the inter prediction type (predDir) is Pred_L0 (S182).

  Next, it is inspected whether the slice type is a B slice (S183). If the slice type is B slice (Y in S183), the second supplement that the motion vector (mvL1) of the L1 prediction is (0, 0), the reference index (ref_idx_l1) of the L1 prediction is 0, and the inter prediction type is Pred_BI. A combined motion information candidate is derived (S184), and the second supplemental combined motion information candidate is added to the combined motion information candidate list (S185).

  If the slice type is not B slice (N in S183), the second supplementary combined motion information candidate derived in S182 is added to the combined motion information candidate list (S185).

  Next, the next i is processed (S186). If the process is completed for all i, the process ends.

  Here, in the case of a P slice, the second supplemental combined motion information candidate is a combined motion information candidate having an L0 prediction motion vector of (0, 0), a reference index of i, and an inter prediction type of Pred_L0. In the case of the B slice, the second supplementary combined motion information candidate has an L0 prediction motion vector (0,0), a reference index i, an L1 prediction motion vector (0,0), and a reference index 0. The combined motion information candidate whose inter prediction type is Pred_BI is used.

  This is because the motion vector (0, 0) is effective in a moving image in which a part of a general image is stationary, and the moving image is continuous in the time direction. This is because the reference picture closer to the target image has higher correlation with the processing target image.

  Hereinafter, the second supplementary combined motion information candidate for the B slice will be described in detail.

  First, encoding that does not rearrange the input image order and the encoding order and encoding that rearranges the input image order and the encoding order will be described.

  FIG. 21 is a diagram for explaining the relationship between the processing target picture and the reference picture. FIG. 21A shows a case where the input image order and the encoding order are not rearranged, and FIG. 21B shows a case where the input image order and the encoding order are rearranged. In FIG. 21A, an image with a POC of n + 4 to n + 7 is a reference picture, and an image with a POC of n + 8 is a processing target picture CurPic. In FIG. 21B, images with POC of n + 2, n + 4, n + 6, and n + 8 are reference pictures, and images with POC of n + 5 are processing target pictures CurPic.

  Next, reference picture lists in encoding that does not rearrange the input image order and encoding order and encoding that rearranges the input image order and encoding order will be described. The reference picture list is generated by the reference picture list generation unit 113.

  FIG. 22 is a diagram for explaining an example of the reference picture list. FIG. 22 shows an example in which the number of usable reference pictures in the reference picture list L0 and the number of usable reference pictures in the reference picture list L1 are both four. FIG. 22A shows the state of the reference picture list when the input image order and the encoding order are not rearranged. Assume that the frame memory 110 stores at least a reference picture whose POC is n + 4, a reference picture whose POC is n + 5, a reference picture whose POC is n + 6, and a reference picture whose POC is n + 8. FIG. 22B shows the state of the reference picture list when the input image order and the encoding order are rearranged. Assume that the frame memory 110 stores at least a reference picture whose POC is n + 2, a reference picture whose POC is n + 4, a reference picture whose POC is n + 6, and a reference picture whose POC is n + 8. When the input image order and the encoding order are not rearranged, the reference picture list L0 and the reference picture list L1 are the same, but when the input image order and the encoding order are rearranged, the reference picture list L0 and the reference picture list L1 are It is not the same.

  Next, the second supplementary combined motion information candidate in encoding that does not rearrange the input image order and encoding order and encoding that rearranges the input image order and encoding order will be described.

  FIG. 23 is a diagram for explaining an example of the relationship between the reference index of the second supplementary combined motion information candidate and the POC according to the first embodiment. FIG. 23 shows an example of the second supplementary combined motion information candidate when the number of usable reference pictures in the reference picture list L0 and the number of usable reference pictures in the reference picture list L1 are both four. FIG. 23A shows the reference index of the second supplemental combined motion information candidate when the input image order and the encoding order are not rearranged, and FIG. 23B shows the reference index when the input image order and the encoding order are rearranged. 2 Indicates a reference index of supplementary combined motion information candidates.

  The case of FIG. 23A will be described. Since the reference index for L0 prediction of the 0th (i is 0) second supplementary joint motion information candidate is 0, the reference picture with POC of n + 7 is used for motion compensated prediction of L0 prediction, and the reference index of L1 prediction Since 0 is 0, a reference picture whose POC is n + 7 is used for motion compensated prediction of L1 prediction. Since the motion vectors of L0 prediction and L1 prediction are the same at (0, 0) and the reference pictures are also the same, the prediction signals of L0 prediction and L1 prediction are the same. Therefore, the 0th second supplemental combined motion information candidate has bi-prediction motion information, but has the same prediction signal as the single prediction in which the motion compensation prediction of the reference picture with POC of n + 7 is performed with the motion vector (0, 0). Become.

  For the first second supplemental combined motion information candidate, a reference picture with POC of n + 6 is used for motion compensated prediction for L0 prediction, and a reference picture with POC of n + 7 is used for motion compensated prediction for L1 prediction. This is bi-predictive motion compensated prediction using the latest (closest to the first) reference picture and the second closest reference picture.

  Similarly, the second second supplemental combined motion information candidate is a bi-predictive motion compensated prediction using the latest reference picture and the third closest reference picture, and the third second supplemental combined motion information candidate is the latest Bi-prediction motion compensated prediction using the reference picture and the fourth closest reference picture.

  The case of FIG. 23B will be described. Since the reference index for L0 prediction of the 0th (i = 0) second supplementary combined motion information candidate is 0, the reference picture with POC of n + 4 is used for motion compensated prediction of L0 prediction, and the reference index of L1 prediction Is 0, the reference picture whose POC is n + 6 is used for motion compensated prediction of L1 prediction. Since the reference picture whose POC is n + 4 and the reference picture whose POC is n + 6 are the reference pictures immediately before and immediately after in the display order of the processing target pictures, respectively, they are relatively selected among the second supplemental combined motion information candidates. It is a bi-predicted motion compensated prediction that is considered to have a high rate.

  For the first second supplementary combined motion information candidate, a reference picture with POC of n + 2 is used for motion compensated prediction of L0 prediction, and a reference picture with POC of n + 6 is used for motion compensated prediction of L1 prediction. This is a bi-prediction motion compensated prediction using the second previous reference picture in the display order of the processing target picture and the next reference picture in the display order.

  The second second supplemental combined motion information candidate has bi-prediction motion information, but has the same prediction signal as the single prediction in which the motion picture (0, 0) is used for motion compensation prediction of a reference picture whose POC is n + 6. .

  The third second supplemental joint motion information candidate uses a reference picture with POC of n + 8 for motion compensated prediction of L0 prediction, and uses a reference picture with POC of n + 6 for motion compensated prediction of L1 prediction. This is a bi-prediction motion compensated prediction using the second reference picture in the display order of the processing target picture and the reference picture immediately in the display order.

  As described above, the motion vector of the L0 prediction of the second supplementary joint motion information candidate of the B slice is (0, 0), the reference index of the L0 prediction is incremented by one, and the motion vector of the L1 prediction is (0, 0). ), By setting the reference index of L1 prediction to 0 in which the latest reference picture of the reference picture list of L1 prediction is registered, all the second supplementary combined motion information candidates are converted to bi-prediction using the latest reference picture. can do.

  In addition, when there is no reference picture for L1 prediction, the second supplementary combined motion information candidates are set to simple prediction from L0 prediction, so that the selection of second supplemental combined motion information candidates is increased and prediction of motion information prediction processing is performed. Efficiency can be improved.

  Also, since all the second supplementary combined motion information candidates are different prediction signals, the encoding efficiency can be improved by widening the range of options for the merge mode.

  Also, the same number of second supplemental combined motion information candidates as the number of usable reference pictures in the reference picture list L0 can be derived without depending on the number of usable reference pictures in the reference picture list L1.

  For example, in a moving image in which a part of the image is at least stationary and random noise is mixed, a bi-predictive prediction signal using the most recent reference picture and other reference pictures is used as the most recent reference picture. In some cases, it is possible to obtain a prediction signal with higher accuracy by the filtering effect and the sharpness of each reference picture due to the quantization width than the prediction signal of uni-prediction using only.

  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 deriving a new combined motion information candidate and expanding the range of options, Encoding efficiency can be improved.

  Also, by making all the second supplemental combined motion information candidates bi-predicted, it is possible to increase the probability of deriving the first supplemental combined motion information candidates in adjacent blocks and improve the encoding efficiency. Hereinafter, the effect will be described in detail.

  First, a problem when the second supplemental combined motion information candidate that is a single prediction of L0 prediction is added to the combined motion information candidate list will be described. When the second supplemental combined motion information candidate that is a single prediction of L0 prediction and the predetermined combined motion information candidate in the combined motion information candidate list are combined to derive the first supplemental combined motion information candidate, the predetermined combined motion When the information candidate is a single prediction of L0 prediction, a new second supplementary combined motion information candidate is not derived. In addition, even when the predetermined combined motion information candidate is bi-prediction, the L1 prediction motion vector and the reference image to be combined with the L0 prediction of the predetermined combined motion information candidate are not included in the second supplemental combined motion information candidate. The first supplemental combined motion information candidate using the L0 prediction of the predetermined combined motion information candidate is not derived.

  Here, all the second supplemental combined motion information candidates are set to bi-prediction, so that when combined with predetermined combined motion information candidates in the combined motion information candidate list, more first supplemental combined motion information candidates can be obtained. Derivation is possible, and encoding efficiency can be improved.

  Here, five spatial candidate block groups, two temporal candidate block groups, the upper limit of the maximum number of merge candidates is 5, the maximum number of spatial combination motion information candidates is 4, and the maximum number of temporal combination motion information candidates is 1. However, it is not limited to this.

  Here, the motion vector of the L0 prediction and the L1 prediction is (0, 0), but it does not depend on the motion information of the combined motion information candidates registered in the combined motion information candidate list, and is a statistically frequently used motion. If it is a vector, it will not be limited to this. For example, the motion vector of the second supplemental combined motion information candidate may be an encoded image or a motion vector with a high occurrence frequency of a part of the encoded image, encoded in an encoded stream, and transmitted and set. it can. Also, although the reference index for L1 prediction is set to 0, if the latest reference picture is other than 0, it may be fixed to a reference index other than 0.

  In general, the number of reference pictures that can be used in the reference picture list L0 is often greater than or equal to the number of reference pictures that can be used in the reference picture list L1. The number of reference pictures that can be used in the reference picture list L0 is used to calculate the maximum number to be derived, and the reference index for L1 prediction is fixed by changing the reference index for L0 prediction, but the reference picture list L1 can be used. When the number of reference pictures is larger than the number of reference pictures that can be used in the reference picture list L0, the number of reference pictures that can be used in the reference picture list L1 for calculating the maximum number for deriving the second supplemental joint motion information candidate The reference index for L0 prediction can be fixed by changing the reference index for L1 prediction.

(Configuration of Predictive Vector Mode Determination Unit 120)
Subsequently, a detailed configuration of the prediction vector mode determination unit 120 will be described. FIG. 24 is a diagram illustrating a 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 also installed in the motion vector reproduction unit 211 in the video decoding device 200 that decodes the code sequence generated by the video encoding device 100 according to Embodiment 1. Thus, the same prediction vector candidate list is generated by the moving image encoding device 100 and the moving image decoding device 200.

(Operation of prediction vector mode determination unit 120)
Hereinafter, the operation of the prediction vector mode determination unit 120 will be described. FIG. 25 is a flowchart showing the operation of the prediction vector mode determination unit 120.

  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 (S200). 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 from the prediction vector candidate list of LX prediction supplied from the prediction vector candidate list generation unit 130 as a prediction vector of LX prediction (S201), and the prediction vector of the LX prediction An index is determined (S202).

  The prediction vector determination unit 131 calculates an LX prediction difference vector by subtracting the LX prediction prediction vector from the LX prediction motion vector supplied from the terminal 13 (S203), and the LX prediction difference vector and the LX prediction The prediction vector index of is output.

  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 LX 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 L1 prediction motion vector is (0, 0), the L1 prediction reference index is “−1”, and if the predictive coding mode is Pred_L1, the motion of the L0 prediction is The vector is (0, 0), and the L0 prediction reference index 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. 26 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 derivation unit 150, a spatial scaling prediction vector candidate derivation unit 151, a temporal prediction vector candidate derivation unit 152, a prediction vector list construction unit 153, a redundant prediction vector candidate deletion unit 154, and A prediction vector candidate supplementing unit 155 is included.

(Operation of prediction vector candidate list generation unit 130)
Hereinafter, the function and operation of each unit will be described. FIG. 27 is a flowchart for explaining the operation of the prediction vector candidate list generation unit 130.

  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 (S210 to S212).

  Here, the candidate block group supplied from the terminal 12 is the same candidate block group as in the merge mode.

  The spatial prediction vector candidate derivation unit 150 obtains 0 or 1 spatial prediction vector candidates for LX prediction from the spatial candidate block group of the i-th group (i is 1 or 2) and the LX prediction reference index supplied from the terminal 13. Deriving (S211), the spatial prediction vector candidate of the LX prediction is supplied to the prediction vector list construction unit 153. The detailed operation of the spatial prediction vector candidate derivation unit 150 will be described later. The relationship between the spatial prediction vector candidate derivation unit 150 and the spatial scaling prediction vector candidate derivation unit 151 will also be described later.

  When the processing is completed for the first group and the second group, the prediction vector candidate list generation unit 130 checks whether the time candidate use permission flag (enable_temporal_mvp_flag) is 1 (S213).

  If the time candidate use permission flag is 1 (Y in S213), the temporal prediction vector candidate derivation unit 152 performs LX prediction from the temporal candidate block group supplied from the terminal 12 and the LX prediction reference index supplied from the terminal 13. 0 or 1 temporal prediction vector candidate is derived (S214), and the temporal prediction vector candidate of the LX prediction is supplied to the prediction vector list construction unit 153. Detailed operation of the temporal prediction vector candidate derivation unit 152 will be described later.

  If the time candidate use permission flag is 0 (N in S213), S214 is skipped.

  Next, the prediction vector list construction unit 153 constructs a prediction vector candidate list for LX prediction from 0 to 2 spatial prediction vector candidates for LX prediction and 0 to 1 temporal prediction vector candidates for LX prediction ( In step S215, the prediction vector candidate list of the LX prediction is supplied to the redundant prediction vector candidate deletion unit 154. Here, a maximum of three spatial vector predictor candidates and temporal predictor vector candidates are registered in the LX prediction vector candidate list in this order.

  Next, the redundant prediction vector candidate deletion unit 154 checks the prediction vector candidates registered in the prediction vector candidate list of the LX prediction, and when there are a plurality of prediction vector candidates having the same vector, one prediction vector Other prediction vector candidates are deleted while leaving candidates. Next, when the number of prediction vector candidates registered in the prediction vector candidate list for LX prediction exceeds the maximum number of prediction vector candidates, the number of prediction vector candidates registered in the prediction vector candidate list for LX prediction is The prediction vector candidates behind the prediction vector candidate list of the LX prediction are deleted so that the number of prediction vector candidates is equal to or less than the maximum number (S216), and the prediction vector candidate list of the LX prediction is supplied to the prediction vector candidate supplementing unit 155. Therefore, all the prediction vector candidates registered in the prediction vector candidate list of LX prediction output from the redundant prediction vector candidate deletion unit 154 are different prediction vector candidates. In addition, when two spatial prediction vector candidates for LX prediction remain, the temporal prediction vector candidates for LX prediction are inevitably not registered in the prediction vector candidate list.

  Next, the prediction vector candidate supplementing unit 155 generates a prediction vector supplementing candidate, and adds the prediction vector supplementing candidate so that the number of prediction vector candidates registered in the prediction vector candidate list for LX prediction becomes the maximum number of prediction vector candidates. It adds to the prediction vector candidate list | wrist of LX prediction (S217), and supplies it to the terminal 18.

  Here, the prediction vector supplement candidate is a motion vector (0, 0). Here, although the motion vector (0, 0) is used as the prediction vector supplement candidate, it may be a predetermined value such as (1, 1), may be transmitted in the encoded stream, or the horizontal component of the spatial prediction vector candidate or A motion vector in which the vertical component is +1 or -1 may be used.

(Detailed operation of spatial prediction vector candidate derivation unit 150)
Subsequently, a detailed operation of the spatial prediction vector candidate derivation unit 150 will be described. FIG. 28 is a flowchart for explaining the operation of the spatial prediction vector candidate derivation unit 150. Derivation of spatial prediction vector candidates for LX prediction will be described.

  The following process is repeated for the i-th group (i is 1 or 2) candidate block (S220 to S226). The first group is examined in the order of block E and block A, and the second group is examined in the order of block C, block B and block D.

For each candidate block, the following processing is repeated in the order of L0 prediction and L1 prediction (S221 to S225). Hereinafter, L0 prediction and L1 prediction here will be described as LN prediction.
It is checked whether the LN prediction of the candidate block is valid (S222). The LN prediction of the candidate block is effective when 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 S222), it is checked whether the reference image indicated by the reference index of the LN prediction of the candidate block is the same as the reference image indicated by the reference index of the LX prediction (S223).

  If the reference images are the same (Y in S223), the motion vector for LN prediction of the candidate block is set as a spatial prediction vector candidate for LX prediction (S224), and the process ends.

  If the LN prediction of the candidate block is not valid (N in S222) or the reference images are not identical (N in S223), if the LN prediction is the L0 prediction, the L1 prediction is checked, and if the LN prediction is the L1 prediction, The next candidate block is inspected (S225).

  If the inspection of all candidate blocks is completed (S226), it is checked whether the time candidate use permission flag (enable_temporal_mvp_flag) is 0 (227).

  If the temporal candidate use permission flag is 0 (Y in S227), the spatial scaling prediction vector candidate derivation unit 151 derives 0 or 1 spatial prediction vector candidates for LX prediction (S228), and ends the process. The detailed operation of the spatial scaling prediction vector candidate derivation unit 151 will be described later.

  If the time candidate use permission flag is 1 (N in S227), S228 is skipped and the process is terminated.

  As described above, 0 or 1 spatial prediction vector candidates are derived from each group, and 0 to 2 spatial prediction vector candidates are derived as LX prediction.

(Detailed Operation of Spatial Scaling Prediction Vector Candidate Deriving Unit 151)
Subsequently, a detailed operation of the spatial scaling prediction vector candidate derivation unit 151 will be described. FIG. 29 is a flowchart for explaining the operation of the spatial scaling prediction vector candidate derivation unit 151. Derivation of spatial prediction vector candidates for LX prediction will be described.

  The following processing is repeated for the i-th group (i is 1 or 2) candidate block (S230 to S236). The first group is examined in the order of block E and block A, and the second group is examined in the order of block C, block B and block D.

  For each candidate block, the following processing is repeated in the order of L0 prediction and L1 prediction (S231 to S235). Hereinafter, L0 prediction and L1 prediction here will be described as LN prediction.

  Next, it is checked whether the LN prediction of the candidate block is valid (S232). The LN prediction of the candidate block is effective when 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 S232), it is checked whether the reference image indicated by the reference index of the LN prediction of the candidate block is the same as the reference image indicated by the reference index of the LX prediction (S233).

  If the reference images are not identical (Y in S233), a spatial prediction vector candidate is derived using the LN prediction motion vector of the candidate block as a reference vector for LX prediction (S234), and the process ends. A detailed method for deriving the spatial prediction vector candidate by the spatial scaling prediction vector candidate deriving unit 151 will be described later.

  If the LN prediction of the candidate block is not valid (N in S232) or the reference images are the same (N in S233), if the LN prediction is the L0 prediction, the L1 prediction is checked, and if the LN prediction is the L1 prediction, The next candidate block is inspected (S235).

  If the inspection of all candidate blocks is completed (S236), the process is terminated.

  Next, a detailed method for deriving a spatial prediction vector candidate by the spatial scaling prediction vector candidate deriving unit 151 will be described. The distance between the images of the reference image NeiRefLXPic and the processing target image CurPic referred to by the LX prediction reference vector is td, the distance between the reference image RefLXPic and the processing target image CurPic indicated by the reference index of the LX prediction is tb, and the reference motion of the LX prediction Assuming that the vector is mvLX, the spatial prediction vector candidate mvScLX is calculated by the above-described Expression 1 or Expression 2 to Expression 4.

(Detailed operation of temporal prediction vector candidate derivation unit 152)
Subsequently, a detailed operation of the temporal prediction vector candidate derivation unit 152 will be described. FIG. 30 is a flowchart for explaining the operation of the temporal prediction vector candidate derivation unit 152. Derivation of temporal prediction vector candidates for LX prediction will be described.

  The following processing is repeated for the time candidate block (S240 to S243). Time candidate blocks are examined in the order of block H and block I.

  First, it is checked whether the LN prediction of the candidate block is valid (S241). Here, the LN prediction is the same as the LX prediction, but the LN prediction may not be the same as the LX prediction. The LN prediction of the candidate block is effective when 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 S241), a temporal prediction vector candidate is derived using the LN prediction motion vector of the candidate block as a reference vector for LX prediction (S242), and the process ends. A detailed method for deriving temporal prediction vector candidates will be described later.

  If the LN prediction of the candidate block is not valid (N in S241), the next candidate block is inspected (S243).

  If the inspection of all candidate blocks is completed (S243), the process is terminated.

  Next, a detailed method for deriving temporal prediction vector candidates will be described. The inter-image distance between ColPic having a temporal candidate block and ColRefLXPic, which is a picture that the temporal candidate block refers to in motion compensated prediction of LN prediction, is td, and the inter-image distance between the reference image RefLXPic and the processing target image CurPic indicated by the reference index of LX prediction Tb, and the reference motion vector for LX prediction is mvLX, and the temporal prediction vector candidate mvLXCol is calculated by Equation 1 or Equation 2 to Equation 4 described above.

(Configuration of moving picture decoding apparatus 200)
Next, the moving picture decoding apparatus according to the first embodiment will be described. FIG. 31 is a diagram showing 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. Slice type determination, maximum reference index that can be used in a slice, coding block division, skip mode determination, prediction block size type determination, prediction block size and position of prediction block in encoding block (prediction block Position information) and whether the predictive coding mode is intra are determined by the decoding control unit 208 outside the moving image decoding apparatus 200 and supplied to the moving image decoding apparatus 200. The reference picture list is generated by a reference picture list generation unit 209 outside the video decoding device 200 and supplied to the video decoding device 200. In the first embodiment, a case where the predictive coding mode is not intra will be described. In Embodiment 1, a B picture (B slice) corresponding to bi-prediction will be described unless otherwise specified, but L1 prediction may be omitted for a P picture (P slice) not corresponding to bi-prediction.

  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. Note that the slice type, the reference picture list, the maximum value of the reference index that can be used in the slice, the position information of the prediction block to be decoded, and the prediction block size are assumed to be shared in the moving picture decoding apparatus 200 and are not illustrated.

  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.
The reference picture list generation unit 209 generates a reference picture list according to the slice type supplied from the decoding control unit 208. If the slice type is P slice or B slice, the reference picture list L0 is generated, and if the slice type is B slice, the reference picture list L1 is generated. A specific method for generating the reference picture list L0 and the reference picture list L1 is the same as that of the reference picture list generation unit 113 of the moving picture coding apparatus 100.

(Detailed configuration of the motion information playback unit 204)
Next, a detailed configuration of the motion information reproducing unit 204 will be described. FIG. 32 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. Also in the skip mode, 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 generates a combined motion information candidate list from the candidate block group supplied from the terminal 33, and combines the index indicated by the merge index supplied from the encoding mode determination unit 210 from the combined motion information candidate list. The motion information candidate motion information is selected and supplied to the terminals 34 and 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. 33 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. FIG. 34 is a diagram for explaining the operation of the combined motion information reproducing unit 212. The combined motion information candidate list generation unit 230 generates a combined motion information candidate list from the candidate block group supplied from the terminal 33 (S310), and supplies the combined motion information candidate list to the combined motion information selection unit 231.

  The combined motion information selection unit 231 acquires the merge index supplied from the terminal 35 (S311), and the combined motion information candidate list supplied from the combined motion information candidate list generation unit 230 is combined by the merge index. The motion information candidate is selected to determine the combined motion information (S312), and the motion information of the combined motion information is supplied to the terminal 34 and the terminal 36.

(Detailed Configuration of Motion Vector Reproducing Unit 211)
Next, a detailed configuration of the motion vector reproduction unit 211 will be described. FIG. 35 is a diagram for explaining the configuration of the motion vector reproduction unit 211. The motion vector reproduction unit 211 includes a prediction vector candidate list generation unit 220, a prediction vector selection unit 221, and an addition unit 222. The terminal 35 is connected to the encoding mode determination unit 210.

(Detailed operation of the motion vector reproduction unit 211)
Hereinafter, the function and operation of each unit will be described. FIG. 36 is a diagram for explaining the operation of the motion vector reproduction unit 211. The motion vector reproduction unit 211 calculates a motion vector for L0 prediction if the inter prediction type supplied from the terminal 35 is L0 prediction, and calculates a motion vector for L1 prediction if the inter prediction type is L1 prediction. If the inter prediction type is BI prediction, motion vectors are calculated for L0 prediction and L1 prediction. The motion vector for each LX prediction is calculated as follows.

  The prediction vector candidate list generation unit 220 generates a prediction vector candidate list for LX prediction from the LX prediction reference index supplied from the terminal 35 and the candidate block group supplied from the terminal 33 (S320), and predicts the LX prediction. The vector list is supplied to the prediction vector selection unit 221.

  The prediction vector selection unit 221 acquires the prediction vector index of LX prediction supplied from the terminal 35 (S321), and uses the prediction vector list of LX prediction from the prediction vector list of LX prediction supplied from the prediction vector candidate list generation unit 220. Is selected as a prediction vector for LX prediction (S322), and the LX prediction motion vector is added to the LX prediction difference vector supplied from the terminal 35 by adding the LX prediction prediction vector. Calculate (S323).

  Motion information is generated by combining the motion vector of the LX prediction and the inter prediction type, and 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.

[Embodiment 2]
The second embodiment will be described below. The operation of the second combined motion information candidate supplementing unit 165 is different from that of the first embodiment. Hereinafter, differences from the first embodiment will be described. FIG. 37 is a flowchart for explaining the operation of the second combined motion information candidate supplementing unit 165 according to the second embodiment. The difference from the second combined motion information candidate supplementing unit 165 of the first embodiment is that steps S187 to S189 are added instead of step S184. Hereinafter, step S187 to step S189 will be described. Here, description will be made assuming that the number of reference pictures that can be used in the reference picture list L0 is equal to or greater than the number of reference pictures that can be used in the reference picture list L1.

  Whether i is equal to or smaller than the maximum value (num_ref_idx_l1_active_minus1) of the reference index of L1 prediction is checked (S187). If i is equal to or less than the maximum value (num_ref_idx_l1_active_minus1) of the reference index for L1 prediction (Y in S187), the L1 prediction motion vector (mvL1) is (0, 0), the L1 prediction reference index (ref_idx_l1) is i, inter A second supplementary combined motion information candidate whose prediction type is Pred_BI is derived (S188), and the second supplemental combined motion information candidate is added to the combined motion information candidate list (S185). If i is not less than or equal to the maximum value (num_ref_idx_l1_active_minus1) of the reference index for L1 prediction (N in S187), the L1 prediction motion vector (mvL1) is (0, 0), the L1 prediction reference index (ref_idx_l1) is 0, and inter A second supplemental combined motion information candidate whose prediction type is Pred_BI is derived (S189), and the second supplemental combined motion information candidate is added to the combined motion information candidate list (S185).

  FIG. 38 is a diagram for explaining an example of the relationship between the reference index of the second supplementary combined motion information candidate and the POC according to the second embodiment. FIG. 38 shows an example where the number of usable reference pictures in the reference picture list L0 is 4 and the number of usable reference pictures in the reference picture list L1 is 2. FIG. 38A shows the reference index of the second supplemental combined motion information candidate when the input image order and the encoding order are not rearranged, and FIG. 38B shows the second index when the input image order and the encoding order are rearranged. 2 Indicates a reference index of supplementary combined motion information candidates.

FIG. 38 (a) will be described.
The L0 prediction reference index and the L1 prediction reference index of the 0th second supplemental combined motion information candidate are both 0, and both the L0 prediction reference picture and the L1 prediction reference picture are reference pictures having a POC of n + 7. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 7.

  The reference index for L0 prediction and the reference index for L1 prediction of the first second supplemental joint motion information candidate for the first are both 1, and the reference picture for L0 prediction and the reference picture for L1 prediction are both reference pictures with a POC of n + 6. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having POC of n + 6 while having bi-prediction motion information.

  The second second supplemental joint motion information candidate is an L0 prediction reference index of 2 and an L1 prediction reference index of 0, and the L0 prediction reference picture is a reference picture with a POC of n + 5. The picture is a reference picture whose POC is n + 7.

  The third second supplemental combined motion information candidate is an L0 prediction reference index of 3 and an L1 prediction reference index of 0, and the L0 prediction reference picture is a reference picture with a POC of n + 4. The picture is a reference picture whose POC is n + 7.

  As described above, when there is a reference picture in the reference picture list L1, the i-th second supplemental combined motion information candidate is represented by the L0 prediction motion vector and the L1 prediction motion vector (0, 0), and the L0 prediction. When the reference index of L1 prediction and the reference index of L1 prediction are i, and the inter prediction type is Pred_BI, and there is no reference picture of the reference picture list L1, the i-th second supplementary combined motion information candidate is selected for L0 prediction. By using motion information with a motion vector of (0, 0), an L0 prediction reference index of i, an L1 prediction reference index of 0, and an inter prediction type of Pred_BI, the same number as the number of available reference pictures in the reference picture list L1 The second supplemental combined motion information candidates up to are derived as bi-prediction as motion information and as single prediction as a prediction signal. In general, the motion compensated prediction using only the reference picture close to the processing target picture having a high correlation with the processing target picture can be performed, and the usable reference of the reference picture list L1 can be used. When more second supplementary combined motion information candidates than the number of pictures are derived, bi-prediction using the latest reference picture can be used.

  In this case, for example, a reference picture with a POC of n + 7 in a part of a moving image has a shielding object and thus does not become the same image as the processing target picture. However, a reference picture with a POC of n + 6 does not have the shielding object. Therefore, when the target picture and the reference picture with POC of n + 6 are the same, it is possible to obtain a highly accurate prediction signal by using the first second supplementary combined motion information candidate. Become.

Subsequently, FIG. 38B will be described.
The reference index for L0 prediction and the reference index for L1 prediction of the 0th second supplemental combined motion information candidate are both 0, the reference picture for L0 prediction is a reference picture whose POC is n + 4, and the reference picture for L1 prediction is The reference picture has a POC of n + 6.

  The reference index for L0 prediction and the reference index for L1 prediction of the first second supplemental joint motion information candidate for the first are both 1, the reference picture for L0 prediction is a reference picture with POC of n + 2, and the reference picture for L1 prediction is The reference picture has a POC of n + 8.

  The reference index for L0 prediction of the second second supplemental combined motion information candidate is 2, the reference index for L1 prediction is 0, and both the reference picture for L0 prediction and the reference picture for L1 prediction have a POC of n + 6. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 6.

  The reference index for L0 prediction of the third second supplemental combined motion information candidate is 3, the reference index for L1 prediction is 0, the reference picture for L0 prediction is a reference picture with POC of n + 8, and the reference picture for L1 prediction Becomes a reference picture whose POC is n + 6.

  As described above, the i-th second supplementary combined motion information candidate is defined such that the motion vector for L0 prediction and the motion vector for L1 prediction are (0, 0), the reference index for L0 prediction and the reference index for L1 prediction are i, By using the motion information with the prediction type Pred_BI, the reference pictures of the L0 prediction and the L1 prediction can be assigned to the reference pictures of the second supplemental joint motion information candidates without leaving them. Here, when the first supplemental combined motion information candidate is derived by combining the second supplemental combined motion information candidate and the predetermined combined motion information candidate in the combined motion information candidate list, the predetermined combined motion information candidate is L0. In the case of prediction single prediction, a new second supplemental combined motion information candidate is not derived. In addition, even when the predetermined combined motion information candidate is bi-prediction, the L1 prediction motion vector and the reference image to be combined with the L0 prediction of the predetermined combined motion information candidate are not included in the second supplemental combined motion information candidate. The first supplemental combined motion information candidate using the L0 prediction of the predetermined combined motion information candidate is not derived.

  Here, all the second supplemental combined motion information candidates are set to bi-prediction, so that when combined with predetermined combined motion information candidates in the combined motion information candidate list, more first supplemental combined motion information candidates can be obtained. Derivation is possible, and encoding efficiency can be improved. Even when the second supplemental combined motion information candidates are combined, the derivation probability of the first supplemental combined motion information candidates can be improved.

[Embodiment 3]
Hereinafter, the third embodiment will be described. The operation of the second combined motion information candidate supplementing unit 165 is different from that of the first embodiment. Hereinafter, differences from the first embodiment will be described. FIG. 39 is a flowchart for explaining the operation of the second combined motion information candidate supplementing unit 165 according to the second embodiment. The difference from the second combined motion information candidate supplementing unit 165 of Embodiment 1 is that Steps S190 to S192 are added instead of Step S184. Also, the calculation formula of MaxNumGenCand, which is the maximum number for deriving the second supplemental combined motion information candidate, is different. Hereinafter, steps S190 to S192 will be described.

First, MaxNumGenCand, which is the maximum number for deriving the second supplemental combined motion information candidate, is calculated from Equation 7 (S180).
MaxNumGenCand = Min (MaxNumMergeCand-NumCandList, Min (num_ref_idx_l0_active_minus1 + 1, num_ref_idx_l1_active_minus1 + 1)); Equation 7

  It is checked whether the reference picture indicated by the reference index for L0 prediction exists in the reference picture list for L1 prediction (S190).

  If the reference picture indicated by the L0 prediction reference index exists in the L1 prediction reference picture list, the L1 prediction motion vector (mvL1) is indicated by (0, 0), and the L1 prediction reference index is indicated by the L0 prediction reference index. A second supplemental joint motion information candidate having a reference index of L1 prediction indicating the same reference picture as the reference picture and an inter prediction type of Pred_BI is derived (S191), and the second supplemental joint motion information candidate is derived as a joint motion information candidate It adds to the list (S185). Here, it is assumed that getRefIdxL1 (ref_idx_10) is a function for obtaining a reference index for L1 prediction indicating the same reference picture as the reference picture indicated by the reference index for L0 prediction.

  If the reference picture indicated by the L0 prediction reference index does not exist in the L1 prediction reference picture list, the L1 prediction motion vector (mvL1) is (0, 0), the L1 prediction reference index is i, and the inter prediction type is A second supplemental combined motion information candidate that is Pred_BI is derived (S192), and the second supplemental combined motion information candidate is added to the combined motion information candidate list (S185).

  When the input image order and the encoding order are not rearranged and it is known that the reference picture list for L0 prediction and the L1 prediction are the same, step S190 and step S191 may not be performed. it can.

  FIG. 40 is a diagram for explaining an example of the relationship between the reference index of the second supplementary combined motion information candidate and the POC according to the third embodiment. FIG. 40 shows an example in which the number of available reference pictures in the reference picture list L0 is 4 and the number of available reference pictures in the reference picture list L1 is 4. FIG. 40A shows the reference index of the second supplementary combined motion information candidate when the input image order and the encoding order are not rearranged, and FIG. 40B shows the second index when the input image order and the encoding order are rearranged. 2 Indicates a reference index of supplementary combined motion information candidates.

FIG. 40A will be described.
The L0 prediction reference index and the L1 prediction reference index of the 0th second supplemental combined motion information candidate are both 0, and both the L0 prediction reference picture and the L1 prediction reference picture are reference pictures having a POC of n + 7. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 7.

  The reference index for L0 prediction and the reference index for L1 prediction of the first second supplemental joint motion information candidate for the first are both 1, and the reference picture for L0 prediction and the reference picture for L1 prediction are both reference pictures with a POC of n + 6. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having POC of n + 6 while having bi-prediction motion information.

  The L0 prediction reference index and the L1 prediction reference index of the second second supplemental combined motion information candidate are both 2, and the L0 prediction reference picture and the L1 prediction reference picture are both reference pictures whose POC is n + 5. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 5.

  The L0 prediction reference index and the L1 prediction reference index of the third second supplemental combined motion information candidate are both 3, and the L0 prediction reference picture and the L1 prediction reference picture are both reference pictures with a POC of n + 4. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion-compensated for the reference picture having the bi-prediction motion information and the POC of n + 4.

Subsequently, FIG. 40B will be described.
The reference index for L0 prediction of the 0th second supplemental combined motion information candidate is 0, the reference index for L1 prediction is 2, and both the reference picture for L0 prediction and the reference picture for L1 prediction have a POC of n + 4. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 4.

  The L0 prediction reference index of the first second supplemental joint motion information candidate is 1, the L1 prediction reference index is 3, and both the L0 prediction reference picture and the L1 prediction reference picture have a POC of n + 2. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 2.

  The reference index for L0 prediction of the second second supplemental combined motion information candidate is 2, the reference index for L1 prediction is 0, and both the reference picture for L0 prediction and the reference picture for L1 prediction have a POC of n + 6. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 6.

  The reference index for L0 prediction of the third second supplemental combined motion information candidate is 3, the reference index for L1 prediction is 1, and both the reference picture for L0 prediction and the reference picture for L1 prediction have a POC of n + 8. Therefore, the prediction signal is the same as the single prediction in which the motion picture (0, 0) is motion compensated for the reference picture having the bi-prediction motion information and the POC of n + 8.

  As described above, when the reference picture indicated by the reference index for L0 prediction exists in the reference picture list for L1 prediction, the same reference picture as the reference picture indicated by the reference index for L0 prediction is used as the reference index for L1 prediction. By using the reference index of the L1 prediction shown, it is possible to derive a second supplemental combined motion information candidate that is bi-predicted while the motion information is the same as the single prediction as the prediction signal.

  In this case, for example, since there is a shielding object at the same position as the processing target block of the latest reference picture, the image at the same position as the processing target block of the latest reference picture is not the same as the image of the processing target block. In a reference picture that is separated by a certain amount of time, since the blockage disappears and the same image as the processing target block is obtained, second supplemental combined motion information that refers to the reference picture from which the blockage is lost By using the candidate, it is possible to obtain a highly accurate prediction signal. More specifically, in FIG. 40A, since there is an occlusion in the reference picture with POC n + 7, the image at the same position as the processing target block of the reference picture with POC n + 7 is the image of the processing target block. Are not the same image, but in the reference image with POC n + 6, since there is no occlusion, the image at the same position as the processing target block of the reference picture with POC n + 6 is the same as the image of the processing target block In such a case, it is possible to obtain a highly accurate prediction signal by selecting the first second supplementary combined motion information candidate.

  In addition, for example, in a moving image in which the processing target picture remains stationary and moves from the next picture, a highly accurate prediction signal is obtained by using a reference picture temporally preceding the processing target picture. It becomes possible. More specifically, in FIG. 40 (b), in the case of a moving image in which there is a motion from a reference picture whose POC is n + 6 even though the processing target picture is still, it is more temporally than the processing target picture. By using the 0th second supplementary combined motion information candidate that refers to the reference picture whose previous POC is n + 4, it is possible to obtain a highly accurate prediction signal.

  Also, the prediction signals of all the second supplemental joint motion information candidates can be made different while assigning the reference pictures of the L0 prediction and the L1 prediction to the reference pictures of the second supplemental joint motion information candidates without leaving them. .

  Furthermore, since step S175 is installed in the first combined motion information candidate supplementing unit 164, the first supplemental combined motion information candidate that is the same as the second supplemental combined motion information candidate in the first combined motion information candidate supplementing unit 164 is displayed. Encoding efficiency can be improved by increasing the probability that combined motion information candidates having different motion information exist in the combined motion information candidate list without being added.

  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, 112 encoding control unit, 113 reference picture list generation unit, 120 prediction vector mode determination unit, 121 merge mode determination unit, 122 prediction encoding mode determination unit , 130 prediction vector candidate list generation unit, 131 prediction vector determination unit, 140 combined motion information candidate list generation unit, 141 combined motion information selection unit, 150 spatial prediction vector candidate derivation unit, 151 spatial scaling prediction vector candidate derivation unit, 1 2 temporal prediction vector candidate derivation unit, 153 prediction vector list construction unit, 154 redundant prediction vector candidate deletion unit, 155 prediction vector candidate supplement unit, 160 spatial combination motion information candidate derivation unit, 161 temporal combination motion information candidate derivation unit, 162 combination Motion information candidate list construction unit, 163 redundant joint motion information candidate deletion unit, 164 first joint motion information candidate supplement unit, 165 second joint motion information candidate supplement unit, 200 video decoding device, 201 code string analysis unit, 202 prediction Error decoding unit, 203 addition unit, 204 motion information reproduction unit, 205 motion compensation unit, 206 frame memory, 207 motion information memory, 208 decoding control unit, 209 reference picture list generation unit, 210 encoding mode determination unit, 211 motion vector Playback unit, 212 combined A motion information reproduction unit; 220 a prediction vector candidate list generation unit; 221 a prediction vector selection unit; 222 an addition unit; 230 a combined motion information candidate list generation unit; and 231 a combined motion information selection unit.

Claims (6)

A video decoding device for deriving motion information including a reference index and a motion vector in units of prediction blocks,
A decoding unit that decodes a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from a code string;
A spatially coupled motion information candidate derivation unit that derives spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation unit for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating unit that generates a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing unit that generates a new combined motion information candidate and adds it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. A combined motion information selection unit for deriving one selected combined motion information candidate,
The predetermined reference index is 0;
The moving picture decoding apparatus, wherein the motion vector having a preset size is (0, 0). A moving picture decoding method for deriving motion information including a reference index and a motion vector in units of prediction blocks,
A decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from a code string;
A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating step for generating a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing step for generating a new combined motion information candidate and adding it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. A combined motion information selection step for deriving the selected one combined motion information candidate,
The predetermined reference index is 0;
A moving picture decoding method, wherein the motion vector having a preset size is (0, 0). A moving picture decoding program for deriving motion information including a reference index and a motion vector in units of prediction blocks,
A decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from a code string;
A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating step for generating a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing step for generating a new combined motion information candidate and adding it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. , Causing the computer to execute a combined motion information selection step for deriving the selected one combined motion information candidate,
The predetermined reference index is 0;
A moving picture decoding program characterized in that the motion vector having a preset size is (0, 0). A receiving device for deriving motion information including a reference index and a motion vector in units of prediction blocks from an encoded sequence,
A receiving unit that receives encoded data in which a moving image is encoded;
A packet processing unit that packet-processes the encoded data to generate the encoded sequence;
A decoding unit that decodes a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code string;
A spatially coupled motion information candidate derivation unit that derives spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation unit for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating unit that generates a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing unit that generates a new combined motion information candidate and adds it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. A combined motion information selection unit for deriving one selected combined motion information candidate,
The predetermined reference index is 0;
The receiving apparatus according to claim 1, wherein the motion vector having a preset size is (0, 0). A receiving method for deriving motion information including a reference index and a motion vector in units of prediction blocks from an encoded sequence,
A reception step of receiving encoded data in which a moving image is encoded;
A packet processing step of packet-processing the encoded data to generate the encoded sequence;
A decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code string;
A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating step for generating a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing step for generating a new combined motion information candidate and adding it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. A combined motion information selection step for deriving the selected one combined motion information candidate,
The predetermined reference index is 0;
The receiving method according to claim 1, wherein the motion vector having a preset size is (0, 0). A receiving program for deriving motion information including a reference index and a motion vector in units of prediction blocks from an encoded sequence,
A reception step of receiving encoded data in which a moving image is encoded;
A packet processing step of packet-processing the encoded data to generate the encoded sequence;
A decoding step of decoding a specific index for specifying a combined motion information candidate to be used for the prediction block to be decoded from the code string;
A spatially coupled motion information candidate derivation step for deriving spatially coupled motion information candidates from motion information of a plurality of the predicted blocks that have been decoded in the vicinity of the prediction block to be decoded;
A temporally combined motion information candidate derivation step for deriving temporally combined motion information candidates from motion information of the predicted block in a decoded picture different from a picture with the prediction block to be decoded;
A combined motion information candidate list generating step for generating a combined motion information candidate list that is a list of combined motion information candidates using the spatially combined motion information candidates and the temporally combined motion information candidates;
A motion vector having a preset size and direction when the reference index indicates an available reference picture, and a reference index when the reference index does not indicate an available reference picture. A combined motion information candidate supplementing step for generating a new combined motion information candidate and adding it to the combined motion information candidate list,
Based on the decoded specific index, one combined motion information candidate is selected from the combined motion information candidate list to which the new combined motion information candidate has been added, and is used as the motion information of the prediction block to be decoded. , Causing the computer to execute a combined motion information selection step for deriving the selected one combined motion information candidate,
The predetermined reference index is 0;
The receiving program according to claim 1, wherein the motion vector having a preset size is (0, 0).

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