WO2013001803A1

WO2013001803A1 - Image encoding device, image encoding method, image encoding program, image decoding device, image decoding method, and image decoding program

Info

Publication number: WO2013001803A1
Application number: PCT/JP2012/004148
Authority: WO
Inventors: 英樹竹原; 博哉中村; 福島　茂
Original assignee: 株式会社Ｊｖｃケンウッド
Priority date: 2011-06-30
Filing date: 2012-06-27
Publication date: 2013-01-03
Also published as: KR102365353B1; KR20220025216A; KR20210091356A; KR102464103B1

Abstract

A candidate list generator selects, from a plurality of encoded blocks adjacent to a block to be encoded, a plurality of blocks individually having one or two items of motion information that include at least motion vector information and reference image information, and generates, from the motion information in the selected blocks, a candidate list including candidates of motion information used for motion-compensated prediction. A first motion information acquisition unit acquires motion information of a first prediction list from a first candidate included in the candidates. A second motion information acquisition unit acquires motion information of a second prediction list from a second candidate included in the candidates. A selected candidate generator combines the motion information of the first prediction list acquired from the first motion information acquisition unit and the motion information of the second prediction list acquired from the second motion information acquisition unit, and generates new candidates of motion information.

Description

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

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

In general video compression coding, motion compensation prediction is used. Motion compensation prediction divides the target image into fine blocks, uses the decoded image as a reference image, and based on the amount of motion indicated by the motion vector, the position of the position moved from the target block of the target image to the reference block of the reference image This is a technique for generating a signal as a prediction signal. Some motion compensation predictions are performed unidirectionally using one motion vector, and others are performed bidirectionally using two motion vectors.

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

MPEG-4AVC improves the efficiency of motion compensation prediction by making the block size of motion compensation prediction finer and more diverse than MPEG-2. On the other hand, since the number of motion vectors increases by making the block size finer, the code amount of the encoded vector becomes a problem.

Therefore, in MPEG-2, the motion vector of the block adjacent to the left of the block to be processed is simply used as the prediction vector. In MPEG-4 AVC, the prediction vector is obtained by using the median of the motion vectors of a plurality of adjacent blocks as the prediction vector. And the increase in the code amount of the encoded vector is suppressed. Further, direct motion compensation prediction is known in MPEG-4 AVC. Direct motion compensated prediction generates a new motion vector by scaling the motion vector of a block at the same position as the processing target block of another encoded image by the distance between the target image and two reference images. The motion compensation prediction is realized without transmitting the quantization vector.

Also, motion compensation prediction that realizes motion compensation prediction without transmitting an encoded vector using motion information of a block adjacent to a processing target block is known (see, for example, Patent Document 1).

JP-A-10-276439

As described above, direct motion compensated prediction that does not transmit an encoded vector focuses on the continuity of motion of a block that is in the same position as a processing target block and a processing target block of another image that has been encoded. Further, Patent Document 1 focuses on the continuity of movement of a processing target block and a block adjacent to the processing target block. As a result, by using the motion information of other blocks, the encoding efficiency is improved without encoding the motion information including the difference vector as the encoded vector.

However, in the conventional motion compensated prediction, the motion of the processing target block is shifted to the motion of the processing target block and the adjacent block, or the motion of a block around the same position as the processing target block of another encoded image. In such a case, the motion information including the difference vector must be encoded, and there is a difficult aspect that the improvement of the encoding efficiency is not sufficiently exhibited.

The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for further improving the coding efficiency of motion information including a motion vector.

In order to solve the above-described problem, an image encoding device according to an aspect of the present invention is an image encoding device that performs motion compensation prediction, and includes a plurality of encoded blocks adjacent to an encoding target block, A plurality of blocks each having one or two pieces of motion information including at least vector information and reference image information are selected, and motion information candidates used for motion compensation prediction are included from the motion information of the selected blocks A candidate list generation unit (140) for generating a candidate list, a first motion information acquisition unit (161) for acquiring motion information of the first prediction list from the first candidate included in the candidates, and the candidates A second motion information acquisition unit (162) that acquires motion information of the second prediction list from the second candidate included, and the first motion information acquired by the first motion information acquisition unit (161). A selection candidate generation unit (163) that generates a new candidate for motion information by combining the motion information of the prediction list and the motion information of the second prediction list acquired by the second motion information acquisition unit (162). And).

The candidate list generation unit (140) generates a candidate list including new candidates generated by the selection candidate generation unit (163) when the number of candidates is less than the set maximum number. Also good.

The candidate list generation unit (140) generates a candidate list including one or more new candidates generated by the selection candidate generation unit (163) so that the number of candidates does not exceed the maximum number. It may be generated.

A code string generation unit (104) for encoding candidate specifying information for specifying a candidate for motion information used for motion compensation prediction in the candidate list may be further included.

The candidate list generation unit (140) may assign candidate specifying information larger than the candidate to the new candidate generated by the selection candidate generation unit (163).

The first prediction list and the second prediction list may be different prediction lists.

The candidate list generation unit (140) may include motion information derived from motion information of a block of an image temporally different from the image including the encoding target block in the candidate list.

The first motion information acquisition unit (161) may search for the candidates according to a first priority order, and may select a valid candidate as the first candidate. The second motion information acquisition unit (162) may search for the candidates according to a second priority order and set a valid candidate as the second candidate.

The first motion information acquisition unit (161) may use a predetermined candidate among the candidates as the first candidate. The second motion information acquisition unit (162) may use another predetermined candidate among the candidates as the second candidate.

The selection candidate generation unit (163) includes the first prediction list motion information and the first prediction list motion information acquired by the first motion information acquisition unit (161) and the second motion information acquisition unit (162). If both pieces of motion information in the second prediction list are valid, the new candidate may be generated.

The new candidate may have two pieces of motion information. The new candidate may have one piece of motion information.

Another aspect of the present invention is an image encoding method. This method is an image encoding method for performing motion compensation prediction, and each of motion information including at least motion vector information and reference image information from a plurality of encoded blocks adjacent to an encoding target block. Selecting a plurality of blocks having one or two and generating a candidate list including motion information candidates used for motion compensation prediction from the motion information of the selected blocks; and a first included in the candidate list Obtaining the motion information of the first prediction list from the candidates, obtaining the motion information of the second prediction list from the second candidates included in the candidate list, and the motion of the first prediction list Combining the information and the motion information of the second prediction list to generate a new candidate for motion information.

An image decoding device according to an aspect of the present invention is an image decoding device that performs motion compensation prediction, and includes at least motion vector information and reference image information from a plurality of decoded blocks adjacent to a decoding target block. A candidate list generation unit (230) that selects a plurality of blocks each having one or two pieces of motion information and generates a candidate list including motion information candidates used for motion compensation prediction from the motion information of the selected blocks. A first motion information acquisition unit (161) that acquires motion information of the first prediction list from the first candidate included in the candidate, and a second prediction list from the second candidate included in the candidate A second motion information acquisition unit (162) that acquires the motion information of the first prediction list acquired by the first motion information acquisition unit (161), and the second Comprising a combination of motion information of the second prediction lists acquired by the motion information obtaining section (162), selecting a candidate generation unit for generating a new candidate motion information (163), the.

The candidate list generation unit (230) generates a candidate list including new candidates generated by the selection candidate generation unit (163) when the number of candidates is less than the set maximum number. Also good.

The candidate list generation unit (230) generates a candidate list including one or more new candidates generated by the selection candidate generation unit (163) so that the number of candidates does not exceed the maximum number. It may be generated.

A code string analyzing unit (201) for decoding candidate specifying information for specifying a candidate for motion information used for motion compensated prediction in the candidate list, and using the decoded candidate specifying information, the candidate list generating unit A selection unit (231) that selects one candidate from the selection candidates included in the candidate list generated in (230) may be further provided.

The candidate list generation unit (230) may assign candidate specifying information larger than the candidate to the new candidate generated by the selection candidate generation unit (163).

The candidate list generation unit (230) may include motion information derived from motion information of a block of an image temporally different from the image including the decoding target block in the candidate list.

Another aspect of the present invention is an image decoding method. This method selects and selects a plurality of blocks each having one or two pieces of motion information including at least motion vector information and reference image information from a plurality of decoded blocks adjacent to the decoding target block. Generating a candidate list including motion information candidates used for motion compensated prediction from the motion information of the obtained block, and acquiring motion information of the first prediction list from the first candidate included in the candidate list And generating a new candidate for motion information by combining the motion information of the first prediction list and the motion information of the second prediction list.

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, the encoding efficiency of motion information including motion vectors can be further improved.

It is a figure for demonstrating the example which divides | segments an image into the largest encoding block. 2A and 2B are diagrams for explaining an encoded block. FIGS. 3A to 3D are diagrams for explaining a prediction block. It is a figure for demonstrating a prediction block size. It is a figure for demonstrating prediction encoding mode. FIGS. 6A to 6D are diagrams for explaining the prediction direction of motion compensation prediction. It is a figure for demonstrating an example of the syntax of a prediction block. FIGS. 8A to 8C are views for explaining a truncated unary code string of a merge index. It is a figure for demonstrating the structure of the moving image encoder which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the management method of the motion information in the motion information memory of FIG. It is a figure for demonstrating the structure of the motion information generation part of FIG. It is a figure for demonstrating the structure of the difference vector calculation part of FIG. It is a figure for demonstrating a space candidate block group. It is a figure for demonstrating a time candidate block group. It is a figure for demonstrating the structure of the joint motion information determination part of FIG. It is a figure for demonstrating the structure of the joint motion information candidate production | generation part of FIG. It is a figure for demonstrating the structure of the bidirectional | two-way joint motion information candidate list production | generation part of FIG. It is a figure for demonstrating a candidate number management table. FIGS. 19A and 19B are diagrams for explaining conversion from a merge candidate number to a merge index. It is a flowchart for demonstrating the operation | movement of the encoding of the moving image encoder which concerns on Embodiment 1 of this invention. 10 is a flowchart for explaining an operation of a motion information generation unit in FIG. 9. 12 is a flowchart for explaining an operation of a difference vector calculation unit in FIG. 11. It is a flowchart for demonstrating operation | movement of the joint motion information determination part of FIG. 18 is a flowchart for explaining the operation of the bidirectional combined motion information candidate list generation unit in FIG. 16. It is a flowchart for demonstrating operation | movement of the production | generation of a space joint motion information candidate list. It is a flowchart for demonstrating the operation | movement of the production | generation of a time combination motion information candidate list. It is a flowchart for demonstrating operation | movement of the production | generation of a bidirectional | two-way joint motion information candidate list. It is a flowchart for demonstrating operation | movement of the reference direction movement information determination part of FIG. It is a flowchart for demonstrating operation | movement of the reverse direction motion information determination part of FIG. It is a figure for demonstrating determination of the prediction direction of a bidirectional | two-way joint motion information candidate. FIGS. 31A to 31C are diagrams for explaining an extended example of determining the prediction direction of the bidirectional combined motion information candidate. It is a figure for demonstrating the structure of the moving image decoding apparatus which concerns on Embodiment 1 of this invention. FIG. 33 is a diagram for describing a configuration of a motion information reproducing unit in FIG. 32. It is a figure for demonstrating the structure of the motion vector reproduction | regeneration part of FIG. It is a figure for demonstrating the structure of the joint motion information reproduction | regeneration part of FIG. It is a flowchart for demonstrating the decoding operation | movement of the moving image decoding apparatus which concerns on Embodiment 1 of this invention. 33 is a flowchart for explaining an operation of a motion information reproducing unit in FIG. 32. It is a flowchart for demonstrating operation | movement of the motion vector reproduction | regeneration part of FIG. It is a flowchart for demonstrating operation | movement of the joint motion information reproduction | regeneration part of FIG. 40A and 40B are diagrams for explaining a candidate number management table according to the first modification. FIG. 10 is a diagram for explaining another candidate number management table according to the first modification of the first embodiment. It is a flowchart for derivation | leading-out of a bidirectional | two-way joint motion information candidate (BD2). It is a flowchart for demonstrating derivation | leading-out of a bidirectional | two-way joint motion information candidate (BD3). 10 is a flowchart for explaining an operation of a backward motion information determination unit according to the second modification of the first embodiment. 10 is a flowchart for explaining an operation of a backward motion information determination unit according to Modification 3 of Embodiment 1. FIG. 10 is a diagram for describing a configuration of a combined motion information candidate generation unit according to Modification 4 of Embodiment 1. It is a figure for demonstrating operation | movement of the reference direction motion information determination part which concerns on the modification 4 of Embodiment 1, and operation | movement of a reverse direction motion information determination part. It is a figure for demonstrating the combination of the motion information with which the two prediction directions which concern on the modification 5 of Embodiment 1 are the same. 49 (a) and 49 (b) are diagrams for explaining a predetermined combination of BD0 and BD1 according to the sixth modification of the first embodiment. FIG. 6 is a diagram (part 1) for explaining the effect of the first embodiment; FIG. 8 is a diagram (part 2) for explaining the effect of the first embodiment; FIG. 6 is a diagram (No. 3) for explaining the effect of the first embodiment; FIGS. 53A and 53B are diagrams for explaining the syntax for encoding the candidate number management table of the second embodiment in the encoded stream. FIG. 10 is a diagram for explaining a candidate number management table according to the third embodiment. FIG. 10 is a diagram for illustrating a configuration of a combined motion information candidate generation unit according to the third embodiment. 10 is a flowchart for explaining an operation of a combined motion information candidate generation unit according to the third embodiment. 10 is a flowchart for explaining an operation of a candidate number management table changing unit according to the third embodiment. 58 (a) to 58 (c) are diagrams for explaining examples of changing the candidate number management table of the candidate number management table changing unit according to the third embodiment. 15 is a flowchart for explaining an operation of a candidate number management table changing unit according to the first modification of the third embodiment. FIGS. 60A and 60B are diagrams for explaining the candidate number management table of the candidate number management table changing unit according to the first modification of the third embodiment. 15 is a flowchart for explaining an operation of a candidate number management table changing unit according to the second modification of the third embodiment. 22 is a flowchart for explaining an operation of a candidate number management table changing unit according to the third modification of the third embodiment. 10 is a flowchart for explaining an operation of a reference direction motion information determination unit according to the fourth embodiment. FIG. 25 is a diagram for illustrating a configuration of a combined motion information candidate generation unit according to the fifth embodiment. FIG. 20 is a diagram for explaining a candidate number management table according to the sixth embodiment. 18 is a flowchart for explaining an operation of a reference direction determination unit according to the sixth embodiment. It is a figure for demonstrating the calculation method of the motion vector mvL0t of a time coupling | bonding motion information candidate, and mvL1t.

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

Currently, devices 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 highly efficient information, compression using motion compensation prediction using temporal redundancy and orthogonal transform such as discrete cosine transform using spatial redundancy Encode.

In 1995, the MPEG-2 video (ISO / IEC １８ 13818-2) encoding system was established as a general-purpose video compression encoding system, and used for DVD and D-VHS (registered trademark) standard digital VTR magnetic tapes, etc. It is widely used as an application for storage media and digital broadcasting.

Furthermore, in 2003, a joint effort between the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) Joint Technical Committee (ISO / IEC) and the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) -4 AVC / H. An encoding system called H.264 (144 / 96-10 in ISO / IEC and H.264 in ITU-T, hereinafter referred to as MPEG-4AVC) has been established as an international standard.

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

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

FIGS. 2A and 2B show an example of division of the maximum coding block. In the example of FIG. 2A, 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.

(Prediction block)
In the embodiment of the present invention, the encoded block is further divided into prediction blocks. The prediction block division patterns are shown in FIGS. 3A is 2N × 2N that does not divide the encoded block, FIG. 3B is 2N × N that is horizontally divided, FIG. 3C is N × 2N that is vertically divided, and FIG. 3D. Indicates N × N divided horizontally and vertically. In other words, as shown in FIG. 4, the prediction block size includes a CU division number of 0 and a maximum prediction block size of 64 pixels × 64 pixels to a CU division number of 3 and a minimum prediction block size. There are 13 predicted block sizes up to 4 pixels x 4 pixels.

In the embodiment of the present invention, 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. Further, although the prediction block division patterns are shown in FIGS. 3A to 3D, the division is not limited to this as long as it is divided into one or more.

(Predictive coding mode)
In the embodiment of the present invention, the prediction direction of motion compensation prediction and the number of encoded vectors can be switched by the block size of the prediction block. Here, an example of a predictive coding mode in which the prediction direction of motion compensation prediction and the number of coding vectors are associated will be briefly described with reference to FIG.

The prediction coding mode shown in FIG. 5 includes a unidirectional mode (UniPred) in which the prediction direction of motion compensation prediction is unidirectional and the number of coding vectors is 1, and the prediction direction of motion compensation prediction is bidirectional. There is a bidirectional mode (BiPred) in which the number of encoded vectors is 2, and a merge mode (MERGE) in which the prediction direction of motion compensation prediction is unidirectional or bidirectional and the number of encoded vectors is 0. There is also an intra mode (Intra) which is a predictive coding mode in which motion compensation prediction is not performed.

(Reference image index)
In the embodiment of the present invention, it is possible to select an optimal reference image from a plurality of reference images in motion compensation prediction in order to improve the accuracy of motion compensation prediction. Therefore, the reference image used in the motion compensation prediction is encoded in the encoded stream together with the encoded vector as a reference image index. The reference image index used in motion compensation prediction is a numerical value of 0 or more. A plurality of reference images that can be selected by the reference image index are managed in a reference index list. If the prediction direction of motion compensation prediction is unidirectional, one reference image index is encoded. If the prediction direction of motion compensation prediction is bidirectional, a reference image index indicating a reference image in each prediction direction is encoded. (See FIG. 5).

(Predicted vector index)
In HEVC, in order to improve the accuracy of a prediction vector, it is considered to select an optimal prediction vector from among a plurality of prediction vector candidates and to encode a prediction vector index for indicating the selected prediction vector. Yes. In the embodiment of the present invention, the prediction vector index is introduced. If the prediction direction of motion compensation prediction is unidirectional, one prediction vector index is encoded. If the prediction direction of motion compensation prediction is bidirectional, a prediction vector index indicating a prediction vector in each prediction direction is encoded. (See FIG. 5).

(Merge index)
In HEVC, in order to further improve the coding efficiency, an optimum block is selected from among a plurality of adjacent block candidates and a block located at the same position as a processing target block of another coded image, and the selected block is selected. Encoding and decoding a merge index indicating This is a motion compensation prediction technique (merge technique) in which motion information including a prediction direction, motion vector information, and reference image information of a motion compensation prediction of a block indicated by a selected merge index is used in a processing target block. In the embodiment of the present invention, the above-described merge index (merge technique) is introduced. As shown in FIG. 5, one merge index is encoded when the prediction encoding mode is the merge mode. If the motion information is bidirectional, the motion information includes motion vector information and reference image information in each prediction direction.

Hereinafter, motion information possessed by a block that may be indicated by the merge index is referred to as a combined motion information candidate, and an aggregate of combined motion information candidates is referred to as a combined motion information candidate list.

(Forecast direction)
In the embodiment of the present invention, two directions of the L0 direction and the L1 direction are set as the prediction directions of the motion compensation prediction. Here, the prediction direction of motion compensation prediction will be briefly described with reference to FIGS. When the prediction direction of motion compensation prediction is unidirectional, either the L0 direction or the L1 direction is used. FIG. 6A shows a case where the reference image (RefL0Pic) in the unidirectional direction and the L0 direction is at a time before the encoding target image (CurPic). FIG. 6B shows a case where the reference image in the unidirectional direction and the L0 direction is at a time after the encoding target image. The reference image in the L0 direction in FIGS. 6A and 6B may be replaced with a reference image in the L1 direction (RefL1Pic).

In the case of bidirectional, it is expressed as BI direction using two of L0 direction and L1 direction. FIG. 6C shows a case where the reference image in the L0 direction is at a time before the encoding target image and the reference image in the L1 direction is at a time after the encoding target image. . FIG. 6D shows a case in which the reference image in the L0 direction and the reference image in the L1 direction are at a time before the encoding target image. The reference image in the L0 direction in FIGS. 6C and 6D may be replaced with the reference image in the L1 direction (RefL1Pic), and the reference image in the L1 direction may be replaced with the reference image in the L0 direction. As described above, the L0 direction and the L1 direction, which are prediction directions of motion compensation prediction, can be indicated in either the forward direction or the backward direction in terms of time. In addition, a plurality of reference images can exist in each of the L0 direction and the L1 direction, the reference image in the L0 direction is registered in the reference image list L0, and the reference image in the L1 direction is registered in the reference image list L1, The position of the reference image in the reference image list is designated by the reference image index in each prediction direction, and the reference image is determined. Hereinafter, the prediction direction is the L0 direction is a prediction direction that uses motion information associated with the reference image registered in the reference image list L0, and the prediction direction is the L1 direction is registered in the reference image list L1. The prediction direction uses motion information associated with the reference image.

(Syntax)
An example of the syntax of the prediction block according to the embodiment of the present invention will be described with reference to FIG. Whether the prediction block is intra or inter is specified by the higher-order encoding block, and FIG. 7 shows the syntax when the prediction block is inter. The prediction block includes a merge flag (merge_flag), a merge index (merge_idx), a direction of motion compensation prediction (inter_pred_type), a reference index (ref_idx_l0 and ref_idx_l1), and a difference vector (mvd_l0 [0], mvd_l0 [1], mvd_l [1], mvd ], Mvd_l1 [1]) and prediction vector indexes (mvp_idx_l0 and mvp_idx_l1). [0] of the difference vector indicates a horizontal component and [1] indicates a vertical component.

Here, ref_idx_l0 and mvd_l0 [0], mvd_l0 [1], and mvp_idx_l0 are information regarding the L0 direction, and ref_idx_l1 and mvd_l1 [0], mvd_l1 [1], and mvp_idx_l1 are information regarding the L1 direction. There are three types of inter_pred_type: Pred_L0 (unidirectional in the L0 direction), Pred_L1 (unidirectional in the L1 direction), and Pred_BI (bidirectional in the BI).

(Code amount of motion information)
As can be seen from the syntax of FIG. 7, the merge mode can transmit motion information with one merge index. Therefore, if the prediction errors in the merge mode (merge flag is 1) and non-merge mode (merge flag is 0) are about the same, the merge mode can more efficiently encode motion information. In other words, the efficiency of motion information encoding can be improved by increasing the selection rate of the merge mode.

The syntax of the prediction block according to the embodiment of the present invention is set as shown in FIG. 7, but according to the embodiment of the present invention, the motion information is encoded with less information in the merge mode than in the non-merge mode. What is necessary is not limited to this. For example, the motion information may be only a difference vector.

(Characteristics of merge index)
In FIG. 7, NumMergeCands (), which is a function for calculating the number of merge candidates before the merge index decoding (encoding), calculates the number of prediction vector candidates before the prediction vector index decoding (encoding). NumMvpCands () is installed. These are functions necessary for obtaining the number of candidates because the number of merge candidates and the number of prediction vector candidates change for each prediction block depending on the validity of motion information of adjacent blocks. Note that the motion information of an adjacent block is valid means that the adjacent block is not a block outside the area or the intra mode, and the motion information of the adjacent block is invalid means that the adjacent block is out of the area. It is a block or intra mode.

Note that when the number of merge candidates is 1, the merge index is not decoded (encoded). This is because when the number of merge candidates is 1, it can be uniquely determined without specifying. The same applies to the prediction vector index.

Further, the merge index code string will be described with reference to FIGS. In the embodiment of the present invention, a Trunked Unary code string is used as the code string of the merge index. FIG. 8A shows a merge index code string using a truncated unary code string when the number of merge candidates is two, and FIG. 8B shows a merge using a truncated unary code string when the number of merge candidates is three. FIG. 8C shows a code sequence of the index, and FIG. 8C shows a code sequence of the merge index by the Truncated Unary code sequence when the number of merge candidates is four.

8A to 8C that even when the same merge index value is encoded, the smaller the number of merge candidates, the smaller the number of code bits assigned to the merge index. For example, when the merge index is 1, if the number of merge candidates is two, it is 1 bit of “1”, but if the number of merge candidates is 3, it is 2 bits of “10”.

As described above, the encoding efficiency of the merge index improves as the number of merge candidates decreases. That is, the coding efficiency of the merge index can be improved by leaving candidates with high selectivity and reducing candidates with low selectivity. In addition, when the number of candidates is the same, the code amount of the smaller merge index is smaller, so that the encoding efficiency can be improved by assigning a small merge index to a candidate with a high selection rate.

(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 defined by MPEG-4 AVC. 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.

(Characteristics of motion information of adjacent blocks)
In general, the degree of correlation between the motion information of the processing target block and the motion information of the block adjacent to the processing target block (hereinafter referred to as an adjacent block) is high when the processing target block and the adjacent block have the same motion. For example, this is a case where the region including the processing target block and the adjacent block is translated. In general, the degree of correlation between the motion information of the processing target block and the motion information of the adjacent block also depends on the length of contact between the processing target block and the adjacent block.

(Characteristics of motion information of another image)
On the other hand, a block in the same position as the processing target block (hereinafter referred to as the same position block) on another decoded image generally used in the temporal direct mode or the spatial direct mode, and the processing target block The degree of correlation is high when the block at the same position and the block to be processed are in a stationary state.

Hereinafter, preferred embodiments of a moving picture coding apparatus, a moving picture coding method, and a moving picture coding program according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

[Embodiment 1]
(Configuration of moving picture coding apparatus 100)
FIG. 9 shows a configuration of moving picture coding apparatus 100 according to Embodiment 1 of the present invention. The moving image encoding apparatus 100 is an apparatus that encodes a moving image signal in units of prediction blocks for performing motion compensation prediction. It is assumed that the coding block division, the prediction block size determination, and the prediction encoding mode determination are determined by the higher-order encoding control unit.

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

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

(Function of moving picture coding apparatus 100)
Hereinafter, functions 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 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 quantization and orthogonal transformation 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 the prediction error encoded data supplied from the prediction error encoding unit 103, the merge flag supplied from the motion information generation unit 109, the merge candidate number, the prediction direction of motion compensation prediction, and the reference image index. The difference vector and the prediction vector index are entropy-encoded according to the syntax together with the prediction direction of motion compensation prediction to generate a code string, and the code string is supplied to the terminal 11.

Here, the merge candidate number is converted into a merge index to generate a code string. Here, the merge candidate number is a number indicating the selected combined motion information candidate. The conversion from the merge candidate number to the merge index will be described later. In the first embodiment, a truncated unary code string is used for encoding a merge index and a prediction vector index as described above. However, the code string can be encoded with a smaller number of bits as the number of candidates is smaller. .

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 motion compensation unit 106 performs motion compensation on the reference image in the frame memory 110 indicated by the reference image index supplied from the motion information generation unit 109 based on the motion vector supplied from the motion information generation unit 109, and generates a prediction signal. Generate. If the prediction direction is bidirectional, the prediction signal is obtained by averaging the prediction signals in the L0 direction and the L1 direction.

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 motion vector detection unit 108 detects a motion vector and a reference image index indicating the reference image from the image signal supplied from the prediction block image acquisition unit 101 and an image signal corresponding to a plurality of reference images, and the motion vector and the motion vector The reference image index is supplied to the motion information generation unit 109. If the prediction direction is bidirectional, motion vectors and reference image indexes in the L0 direction and the L1 direction are detected.

A general motion vector detection method calculates an error evaluation value for an image signal corresponding to a reference image moved by a predetermined movement amount from the same position as the image signal of the target image, and moves to minimize the error evaluation value. Let the amount be a motion vector. 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.

The motion information generation unit 109 uses the motion vector and reference image index supplied from the motion vector detection unit 108, the candidate block group supplied from the motion information memory 111, and the reference image indicated by the reference image index in the frame memory 110. , A merge candidate number, or a difference vector and a prediction vector index, and a code flag generation unit 104, a motion compensation unit 106, and a merge flag, a merge candidate number, a reference image index, a difference vector, and a prediction vector index The motion information memory 111 is supplied. A detailed configuration of the motion information generation unit 109 will be described later.

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

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

Also, the motion information memory 111 uses the motion information of the block on the ColPic and the surrounding blocks at the same position as the prediction block to be processed 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 refers to a decoded image different from the prediction block to be processed and stored in the frame memory 110 as a reference image. In Embodiment 1, ColPic is a reference image decoded immediately before. In Embodiment 1, ColPic is a reference image decoded immediately before. However, it may be an encoded image, for example, a reference image immediately before in display order or a reference image immediately after in display order may be used. It can also be specified in the encoded stream.

Here, a method for managing motion information in the motion information memory 111 will be described with reference to FIG. The motion information is stored in each memory area in units of the smallest prediction block. FIG. 10 shows a state where the predicted block size to be processed is 16 pixels × 16 pixels. In this case, the motion information of the prediction block is stored in 16 memory areas indicated by hatching in FIG.

When the predictive coding mode is the intra mode, (0, 0) is stored as the motion vector in the L0 direction and the L1 direction, and “−1” is stored as the reference image index in the L0 direction and the L1 direction. The reference image index “−1” may be any value as long as it can be determined that the mode does not perform motion compensation prediction. From this point onward, unless expressed otherwise, the term “block” refers to the smallest predicted block unit when expressed simply as a block. Further, in the case of a block outside the area, as in the intra mode, (0, 0) is stored as the motion vector in the L0 direction and the L1 direction, and “−1” is stored as the reference image index in the L0 direction and the L1 direction. . When the LX direction (X is 0 or 1) is valid, the reference image index in the LX direction is 0 or more, and when the LX direction is invalid (not valid), the reference image index in the LX direction is “− 1 ”.

Subsequently, a detailed configuration of the motion information generation unit 109 will be described with reference to FIG. FIG. 11 shows the configuration of the motion information generation unit 109. The motion information generation unit 109 includes a difference vector calculation unit 120, a combined motion information determination unit 121, and a predictive coding 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.

The functions of each part are described below. The difference vector calculation unit 120 predicts from the candidate block group supplied from the terminal 12, the motion vector and reference image index supplied from the terminal 13, the reference image supplied from the terminal 14, and the image signal supplied from the terminal 15. A vector index is determined, and a difference vector and a rate distortion evaluation value are calculated. Then, the reference image index, the motion vector, the difference vector, the prediction vector index, and the rate distortion evaluation value are supplied to the prediction encoding mode determination unit 122. The detailed configuration of the difference vector calculation unit 120 will be described later.

The combined motion information 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. Then, the combined motion information determination unit 121 selects a combined motion information candidate from the generated combined motion information candidate list, determines a merge candidate number, calculates a rate distortion evaluation value, and combines the combined motion information candidate. Motion information, the merge candidate number, and the rate distortion evaluation value are supplied to the predictive coding mode determination unit 122. A detailed configuration of the combined motion information determination unit 121 will be described later.

The predictive coding mode determination unit 122 compares the rate distortion evaluation value supplied from the difference vector calculation unit 120 with the rate distortion evaluation value supplied from the combined motion information determination unit 121. If the former is less than the latter, the merge flag is set to “0”. The predictive coding mode determination unit 122 supplies the merge flag, the reference image index, the difference vector, and the prediction vector index supplied from the difference vector calculation unit 120 to the terminal 16, and the motion vector supplied from the difference vector calculation unit 120. The reference image index is supplied to the terminal 50 and the terminal 51.

If the former is greater than or equal to the latter, set the merge flag to 1. The predictive coding mode determination unit 122 supplies the merge flag and the merge candidate number supplied from the combined motion information determination unit 121 to the terminal 16, and the motion vector of the motion information supplied from the combined motion information determination unit 121 and the reference image The index is supplied to the terminal 50 and the terminal 51. Although a specific calculation method of the rate distortion evaluation value is not the main point of the present invention, the details thereof will be omitted. However, the evaluation value has a characteristic that the encoding efficiency increases as the rate distortion evaluation value decreases.

Subsequently, a detailed configuration of the difference vector calculation unit 120 will be described with reference to FIG. FIG. 12 shows the configuration of the difference vector calculation unit 120. The difference vector calculation unit 120 includes a prediction vector candidate list generation unit 130, a prediction vector determination unit 131, and a subtraction unit 132. 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 moving image decoding apparatus 200 that decodes the code sequence generated by the moving image encoding apparatus 100 according to the first embodiment. The image decoding apparatus 200 generates a prediction vector candidate list having no contradiction.

The function of each part will be described below. The prediction vector candidate list generation unit 130 deletes candidate blocks outside the region and candidate blocks in the intra mode from the candidate block group supplied from the terminal 12. Further, when there are a plurality of candidate blocks having overlapping motion vectors, one candidate block is left and deleted. The prediction vector candidate list generation unit 130 generates a prediction vector candidate list from these candidate blocks after deletion, and supplies the prediction vector candidate list to the prediction vector determination unit 131. It is assumed that the predicted vector candidate list generated in this way includes one or more predicted vector candidates that do not overlap. For example, when there is no candidate block having a motion vector, the vector (0, 0) is added to the prediction vector candidate list. If the prediction direction is bidirectional, a prediction vector candidate list is generated and supplied for the L0 direction and the L1 direction.

The prediction vector determination unit 131 selects an optimal prediction vector for the motion vector supplied from the terminal 13 from the prediction vector candidate list supplied from the prediction vector candidate list generation unit 130. The prediction vector determination unit 131 supplies the selected prediction vector to the subtraction unit 132, and supplies a reference vector index and a prediction vector index that is information indicating the selected prediction vector to the terminal 17. If the prediction direction is bidirectional, an optimal prediction vector is selected and supplied for the L0 direction and the L1 direction.

Here, the prediction error amount is calculated from the reference image supplied from the terminal 14 and the image signal supplied from the terminal 15 based on the motion vector of the prediction vector candidate as the optimal prediction vector. Then, a rate distortion evaluation value is calculated from the code amount of the reference image index, the difference vector, and the prediction vector index, and the above-described prediction error amount, and a prediction vector candidate that minimizes the rate distortion evaluation value is selected.

The subtraction unit 132 calculates a difference vector by subtracting the prediction vector supplied from the prediction vector determination unit 131 from the motion vector supplied from the terminal 13, and supplies the difference vector to the terminal 17. If the prediction direction is bidirectional, a difference vector is calculated and supplied for the L0 direction and the L1 direction.

(Candidate block group supplied to prediction vector candidate list generation unit 130)
Here, the candidate block group supplied to the prediction vector candidate list production | generation part 130 is demonstrated using FIG. 13 and FIG. The candidate block group includes a spatial candidate block group and a temporal candidate block group.

FIG. 13 shows adjacent blocks of the prediction block to be processed when the prediction block size to be processed is 16 pixels × 16 pixels. In the first embodiment, the space candidate block group is assumed to be five blocks of block A1, block C, block D, block B1, and block E shown in FIG. Here, the spatial candidate block group is five blocks of block A1, block C, block D, block B1, and block E, but the spatial candidate block group is at least one or more processed adjacent to the prediction block to be processed. Any block may be used, and the present invention is not limited to these. For example, all of block A1, block A2, block A3, block A4, block B1, block B2, block B3, block B4, block C, block D, and block E may be spatial candidate blocks.

Next, the time candidate block group will be described with reference to FIG. FIG. 14 shows a block in a prediction block on ColPic and its peripheral blocks at the same position as the prediction block to be processed when the prediction block size to be processed is 16 pixels × 16 pixels. In the first embodiment, the time candidate block group includes two blocks, block H and block I6 shown in FIG.

Here, the time candidate block group is two blocks of block H and block I6 on ColPic, but the time candidate block group is at least one block on a decoded image different from the prediction block to be processed. There is no limitation to these. For example, all of block I1 to block I16, block A1 to block A4, block B1 to block B4, block C, block D, block E, block F1 to block F4, block G1 to block G4 and block H on ColPic It may be a candidate block. Hereinafter, unless otherwise specified, block A4 is referred to as block A, and block B4 is referred to as block B. Hereinafter, unless otherwise specified, blocks H and I6 are referred to as time blocks.

(Configuration of the combined motion information determination unit 121)
Next, a detailed configuration of the combined motion information determination unit 121 will be described with reference to FIG. FIG. 15 shows the configuration of the combined motion information determination unit 121. The combined motion information determination unit 121 includes a combined motion information candidate generation unit 140 and a combined motion information selection unit 141. The combined motion information candidate generation unit 140 is also installed in the moving image decoding apparatus 200 that decodes the code sequence generated by the moving image encoding apparatus 100 according to Embodiment 1, and is combined with the moving image encoding apparatus 100 and the moving image. The image decoding apparatus 200 generates the same combined motion information list without any contradiction.

The functions of each part are described below. The combined motion information candidate generation unit 140 generates a combined motion information candidate list from the candidate block group supplied from the terminal 12, and supplies the combined motion information candidate list to the combined motion information selection unit 141. A detailed configuration of the combined motion information candidate generation unit 140 will be described later.

The combined motion information selection unit 141 is information that selects an optimal combined motion information candidate from the combined motion information candidate list supplied from the combined motion information candidate generation unit 140 and indicates the selected combined motion information candidate. The merge candidate number is supplied to the terminal 17.

Here, from the prediction image of the combined motion information candidate, the motion vector, and the reference image supplied from the terminal 14 obtained based on the reference image index and the image signal supplied from the terminal 15 as the optimal combined motion information candidate. A prediction error amount is calculated. A rate distortion evaluation value is calculated from the code amount of the merge candidate number and the prediction error amount, and a combined motion information candidate that minimizes the rate distortion evaluation value is selected.

(Candidate block group supplied to the combined motion information candidate generation unit 140)
Here, the candidate block group supplied to the combined motion information candidate generation unit 140 will be described with reference to FIGS. 13 and 14. The candidate block group includes a spatial candidate block group and a temporal candidate block group. In the first embodiment, the space candidate block group is assumed to be four blocks of block A4, block B4, block C, and block E shown in FIG. Here, the spatial candidate block group is four blocks of block A4, block B4, block C, and block E, but the spatial candidate block group may be at least one or more processed blocks adjacent to the prediction block to be processed. What is necessary is not limited to these.

Next, the time candidate block group will be described with reference to FIG. In the first embodiment, the time candidate block group includes two blocks, block H and block I6 shown in FIG. Here, the time candidate block group is the same as the time candidate block group supplied to the prediction vector candidate list generation unit 130, but the time candidate block group is on a decoded image different from the prediction block to be processed. The block is not limited to these as long as it is at least 0 or more blocks.

(Configuration of combined motion information candidate generation unit 140)
Next, a detailed configuration of the combined motion information candidate generation unit 140 that characterizes the first embodiment will be described with reference to FIG. FIG. 16 shows a configuration of the combined motion information candidate generation unit 140. The terminal 18 is connected to the combined motion information selection unit 141. The combined motion information candidate generation unit 140 includes a unidirectional combined motion information candidate list generation unit 150, a first combined motion information candidate list reduction unit 151, a bidirectional combined motion information candidate list generation unit 152, and a second combined motion information candidate list reduction. Part 153.

The functions of each part are described below. The unidirectional combined motion information candidate list generation unit 150 generates a first combined motion information candidate list from the candidate block group supplied from the terminal 12, and reduces the first combined motion information candidate list to the first combined motion information candidate list. To the unit 151.

The first combined motion information candidate list reduction unit 151 includes a plurality of combined motion information candidates having motion information overlapping from the first combined motion information candidate list supplied from the unidirectional combined motion information candidate list generation unit 150. In this case, the second combined motion information candidate list is generated by deleting one of the combined motion information candidates, and the second combined motion information candidate list is supplied to the bidirectional combined motion information candidate list generating unit 152.

The bidirectional combined motion information candidate list generating unit 152 generates a bidirectional combined motion information candidate list from the second combined motion information candidate list supplied from the first combined motion information candidate list reducing unit 151, and the bidirectional combined motion information candidate list is generated. The information candidate list is combined with the second combined motion information candidate list described above to generate a third combined motion information candidate list, and the third combined motion information candidate list is supplied to the second combined motion information candidate list reduction unit 153. . A detailed configuration of the bidirectional combined motion information candidate list generation unit 152 will be described later.

In Embodiment 1, the bidirectional combined motion information candidate list generation unit 152 generates a bidirectional combined motion information candidate (BD0) whose reference direction is L0 and a bidirectional combined motion information candidate (BD1) whose reference direction is L1. Shall. Therefore, there is a possibility that BD0 and BD1 are included in the above-described bidirectional combined motion information candidate list.

The second combined motion information candidate list reduction unit 153 includes a plurality of combined motion information candidates that have overlapping motion information from the third combined motion information candidate list supplied from the bidirectional combined motion information candidate list generation unit 152. In this case, the combined motion information candidate list is generated by deleting one combined motion information candidate, and the combined motion information candidate list is supplied to the terminal 18.

Here, the unidirectional combined motion information candidate is a motion information candidate of a candidate block used in a so-called merge technique, and is motion information obtained from one candidate block. On the other hand, the bidirectional combined motion information is a technique that is a feature of the first embodiment, and is motion information obtained by using two pieces of motion information from two candidate blocks. In this embodiment, one L0 direction and one L1 direction are used as two pieces of motion information.

(Bidirectional combined motion information candidate list generation unit 152)
Next, a detailed configuration of the bidirectional combined motion information candidate list generation unit 152 will be described with reference to FIG. FIG. 17 shows a configuration of the bidirectional combined motion information candidate list generation unit 152. The terminal 19 is connected to the first combined motion information candidate list reduction unit 151, and the terminal 20 is connected to the second combined motion information candidate list reduction unit 153. The bidirectional combined motion information candidate list generation unit 152 includes a reference direction determination unit 160, a reference direction motion information determination unit 161, a reverse direction motion information determination unit 162, and a bidirectional motion information determination unit 163.

The functions of each part are described below. The reference direction determination unit 160 determines the reference direction of the bidirectional combined motion information candidate from the second combined motion information candidate list, and determines the reference direction and the second combined motion information candidate list supplied from the terminal 19 as the reference direction motion information. The data is sent to the determination unit 161. The reference direction for the bidirectional combined motion information candidate (BD0) with the reference direction L0 is the L0 direction, and the reference direction for the bidirectional combined motion information candidate (BD1) with the reference direction L1 is the L1 direction.

The reference direction motion information determination unit 161 determines the reference direction motion vector and the reference image index of the bidirectional combined motion information candidate from the reference direction and the second combined motion information candidate list supplied from the reference direction determination unit 160, The reference direction, the motion vector in the reference direction, the reference image index, and the second combined motion information candidate list are sent to the backward direction motion information determination unit 162.

The backward direction motion information determination unit 162 determines the bidirectional combined motion information candidate from the reference direction, the reference direction motion vector and the reference image index, and the second combined motion information candidate list supplied from the reference direction motion information determination unit 161. A backward motion vector and a reference image index are determined. The backward motion information determination unit 162 sends the motion vector in the reference direction and the reference image index, the backward motion vector and the reference image index, and the second combined motion information candidate list to the bidirectional motion information determination unit 163. In the first embodiment, if the reference direction is the L0 direction, the reverse direction is the L1 direction, and if the reference direction is the L1 direction, the reverse direction is the L0 direction.

The bidirectional motion information determination unit 163 determines a bidirectional combined motion information candidate from the reference direction motion vector and the reference image index supplied from the backward direction motion information determination unit 162, and the backward direction motion vector and the reference image index. . In addition, the bidirectional motion information determination unit 163 generates a third combined motion information candidate list from the second combined motion information candidate list, and sends the third combined motion information candidate list to the terminal 20.

(Candidate number management table)
Here, a candidate number management table indicating the relationship between merge candidate numbers and combined motion information candidates used in Embodiment 1 will be described with reference to FIG. Merge candidate numbers 0 to 6 are combined motion information candidates (A) of block A, combined motion information candidates (B) of block B, and combined motion information candidates (COL) of time blocks included in the combined motion information candidate list, respectively. , Combined motion information candidate (C) of block C, combined motion information candidate (E) of block E, bidirectional combined motion information candidate (BD0) with reference direction L0, and bidirectional combined motion information candidate with reference direction L1 (BD1) is shown. The maximum number of combined motion information candidates included in the combined motion information candidate list is 7 (the maximum value of the merge index is 6). As described above, the merge candidate number of the bidirectional combined motion information candidate (BD0) having the reference direction L0 and the bidirectional combined motion information candidate (BD1) having the reference direction L1 is the merge candidate of the unidirectional combined motion information candidate. Assigned to be larger than the number. Although the candidate number management table used in Embodiment 1 is shown in FIG. 18, it is only necessary that a smaller merge candidate number is assigned to a combined motion information candidate with a higher selection rate.

Here, the maximum number of combined motion information candidates included in the candidate number management table and the combined motion information candidate list is assumed to be shared in the moving picture coding apparatus 100, and is not illustrated. Hereinafter, conversion from the merge candidate number to the merge index will be described with reference to FIGS.

FIG. 19A shows a combined motion information candidate for block A, a combined motion information candidate for block B, a combined motion information candidate for time block, a combined motion information candidate for block C, a combined motion information candidate for block E, and a reference direction. When the bidirectional combined motion information candidate of L0 and the bidirectional combined motion information candidate of the reference direction L1 are all valid, it indicates that the merge candidate number becomes the merge index as it is.

FIG. 19B shows a case in which merge indexes are assigned in ascending order of merge candidate numbers after filling invalid merge candidate numbers when the combined motion information candidates include invalid blocks. As shown in FIG. 19B, when the combined motion information candidate of the block B with the merge candidate number 1 and the block E with the merge candidate number 4 is invalid, the merge index 0 is set to the merge candidate number 0 and the merge index 1 is converted to merge candidate number 2, merge index 2 is converted to merge candidate number 3, merge index 3 is converted to merge candidate number 5, and merge index 4 is converted to merge candidate number 6. As described above, here, the merge index of the bidirectional combined motion information candidate (BD0) having the reference direction L0 and the bidirectional combined motion information candidate (BD1) having the reference direction L1 is greater than the merge index of the unidirectional combined motion information candidate. Is also assigned to be larger.

In the moving picture decoding apparatus 200 that decodes the code sequence generated by the moving picture encoding apparatus 100 according to the first embodiment, the reverse conversion from the merge index to the merge candidate number is performed, and the moving picture encoding apparatus 100 And the moving picture decoding apparatus 200 generates the same candidate number management table with no contradiction.

(Operation of moving picture coding apparatus 100)
Next, an encoding operation in the moving image encoding apparatus 100 according to Embodiment 1 will be described with reference to the flowchart of FIG. 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 of the prediction block and the prediction block size (S100).

The motion vector detection unit 108 detects a reference image index indicating a motion vector and a reference image from the image signal supplied from the predicted block image acquisition unit 101 and image signals corresponding to a plurality of reference images (S101).

The motion information generation unit 109 generates a merge candidate number or a difference vector and a prediction vector index from the motion vector and reference image index supplied from the motion vector detection unit 108 and the candidate block group supplied from the motion information memory 111. (S102).

The motion compensation unit 106 performs motion compensation on the reference image indicated by the reference image index in the frame memory 110 based on the motion vector supplied from the motion vector detection unit 108 to generate a prediction signal. If the prediction direction is bidirectional, an average of the prediction signals in the L0 direction and the L1 direction is generated as a prediction signal (S103).

The subtraction unit 102 calculates a difference between 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 (S104). The prediction error encoding unit 103 performs processing such as quantization and orthogonal transformation on the prediction error signal supplied from the subtraction unit 102 to generate prediction error encoded data (S105).

The code string generation unit 104 includes the prediction error encoded data supplied from the prediction error encoding unit 103, and the merge flag, merge candidate number, reference image index, difference vector, and prediction vector index supplied from the motion information generation unit 109. Is entropy-coded according to the syntax along with the prediction direction to generate a code string (S106).

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 (S107). The frame memory 110 stores the decoded image signal supplied from the adding unit 107 (S108). The motion information memory 111 stores one image of the motion vector supplied from the motion vector detection unit 108 in units of the minimum predicted block size (S109).

Subsequently, the operation of the motion information generation unit 109 will be described using the flowchart of FIG. The difference vector calculation unit 120 includes a candidate block group supplied from the terminal 12, a motion vector and reference image index supplied from the terminal 13, a reference image supplied from the terminal 14, and an image signal supplied from the terminal 15. A prediction vector index is determined, and a difference vector and a rate distortion evaluation value are calculated (S110).

The combined motion information determination unit 121 determines the merge candidate number 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 to obtain the rate distortion evaluation value. Calculate (S111).

The predictive coding mode determination unit 122 compares the rate distortion evaluation value supplied from the difference vector calculation unit 120 with the rate distortion evaluation value supplied from the combined motion information determination unit 121, and merges if the former is smaller than the latter The flag is set to “0”, otherwise, the merge flag is set to “1” (S112).

Next, the operation of the difference vector calculation unit 120 will be described using the flowchart of FIG. The prediction vector candidate list generation unit 130 excludes candidate blocks that are out of the region, candidate blocks that are in the intra mode, and candidate blocks that have overlapping motion vectors from the candidate block group supplied from the terminal 12. A prediction vector candidate list is generated. If the prediction direction is bidirectional, a prediction vector candidate list is generated for the L0 direction and the L1 direction (S120).

The prediction vector determination unit 131 selects an optimal prediction vector for the motion vector supplied from the terminal 13 from the prediction vector candidate list supplied from the prediction vector candidate list generation unit 130. If the prediction direction is bidirectional, an optimal prediction vector is selected for the L0 direction and the L1 direction (S121). The subtraction unit 132 subtracts the prediction vector supplied from the prediction vector determination unit 131 from the motion vector supplied from the terminal 13 to calculate a difference vector. If the prediction direction is bidirectional, a difference vector is calculated for the L0 direction and the L1 direction (S122).

(Operation of the combined motion information determination unit 121)
Subsequently, the operation of the combined motion information determination unit 121 will be described in detail using the flowchart of FIG. The combined motion information candidate generation unit 140 generates a combined motion information candidate list from the candidate block group supplied from the terminal 12 (S130). The combined motion information selection unit 141 selects from the combined motion information candidate list supplied from the combined motion information candidate generation unit 140, the motion vector and reference image index supplied from the terminal 13, and the combined motion information optimal for the prediction direction. Is determined (S131).

(Operation of combined motion information candidate generation unit 140)
Subsequently, the operation of the combined motion information candidate generation unit 140 will be described in detail using the flowchart of FIG. The unidirectional combined motion information candidate list generation unit 150 generates a spatial combined motion information candidate list from candidate blocks obtained by excluding candidate blocks outside the region and candidate blocks in the intra mode from the spatial candidate block group supplied from the terminal 12. (S140). Detailed operations for generating the spatially coupled motion information candidate list will be described later.

The unidirectional combined motion information candidate list generation unit 150 generates a time combined motion information candidate list from candidate blocks obtained by excluding candidate blocks outside the region and candidate blocks in the intra mode from the time candidate block group supplied from the terminal 12. Generate (S141). The detailed operation of generating the time combination motion information candidate list will be described later.

The unidirectional combined motion information candidate list generation unit 150 combines the spatial combined motion information candidate list and the temporal combined motion information candidate list in the order of merge candidate numbers to generate a first combined motion information candidate list (S142).

The first combined motion information candidate list reduction unit 151 includes a plurality of combined motion information candidates having motion information overlapping from the first combined motion information candidate list supplied from the unidirectional combined motion information candidate list generation unit 150. In this case, the second combined motion information candidate list is generated by deleting one combined motion information candidate (S143).

The bidirectional combined motion information candidate list generating unit 152 generates a bidirectional combined motion information candidate list from the second combined motion information candidate list supplied from the first combined motion information candidate list reducing unit 151 (S144). The detailed operation of generating the bidirectional combined motion information candidate list will be described later.

The bidirectional combined motion information candidate list generation unit 152 combines the second combined motion information candidate list and the bidirectional combined motion information candidate list in the order of merge candidate numbers to generate a third combined motion information candidate list (S145). ).

The second combined motion information candidate list reduction unit 153 includes a plurality of combined motion information candidates that have overlapping motion information from the third combined motion information candidate list supplied from the bidirectional combined motion information candidate list generation unit 152. In this case, a combined motion information candidate list is generated by deleting one combined motion information candidate (S146).

Subsequently, the detailed operation of generating the spatially coupled motion information candidate list will be described using the flowchart of FIG. In Embodiment 1, it is assumed that the spatial combination motion information candidate list includes motion information of four or less candidate blocks.

The following processing is repeated for block A, block B, block C and block E, which are the four candidate blocks included in the space candidate block group (S150 to S153). The validity of the candidate block is checked (S151). A candidate block is valid when the candidate block is not out of the region and is not in intra mode. If the candidate block is valid (YES in S151), the motion information of the candidate block is added to the spatially combined motion information candidate list (S152). If the candidate block is not valid (NO in S151), step S152 is skipped.

In the first embodiment, the spatial combination motion information candidate list includes motion information of four or less candidate blocks. However, the number of spatial combination motion information candidate lists may vary depending on the effectiveness of the candidate block. It is not limited.

Subsequently, the detailed operation of generating the time combination motion information candidate list will be described using the flowchart of FIG. In Embodiment 1, it is assumed that the temporal combination motion information candidate list includes motion information of one or less candidate blocks.

The following processing is repeated for time blocks that are two candidate blocks included in the time candidate block group (S160 to S166). The validity of the candidate block is checked (S161). A candidate block is valid when the candidate block is not out of the region and is not in intra mode. If the candidate block is valid (YES in S161), a time combination motion information candidate is generated, the time combination motion information candidate is added to the list (step S162 to step S165), and the process ends. . If the candidate block is not valid (NO in S161), the next candidate block is inspected (S166).

If the candidate block is valid, the prediction direction of the temporally combined motion information candidate is determined (S162). In the first embodiment, the prediction direction of the combined motion information candidate is bidirectional. Next, the reference images in the L0 direction and the L1 direction of the time combination motion information candidate are determined (S163). In the first embodiment, the reference image in the L0 direction is the reference image that is the closest to the processing target image among the reference images in the L0 direction, and the reference image in the L1 direction is the processing target image among the reference images in the L1 direction. The reference image is the closest distance. Here, the reference image in the L0 direction is the reference image that is the closest to the processing target image among the reference images in the L0 direction, and the reference image in the L1 direction is the closest to the processing target image among the reference images in the L1 direction. Although the reference image is at a distance, it is only necessary to determine the reference image in the L0 direction and the reference image in the L1 direction, and the present invention is not limited to this. For example, the reference images in the L0 direction and the L1 direction may be encoded in the encoded stream, the reference image indexes in the L0 direction and the L1 direction may be set to 0, and the L0 used by the adjacent block of the processing target block. Of the reference image in the direction and the reference image in the L1 direction, the most frequently used reference image may be used as a reference image for reference in each of the L0 direction and the L1 direction.

Next, the motion vector of the time combination motion information candidate is calculated (S164). In this embodiment, the temporally combined motion information candidate calculates bidirectional motion information based on the reference image ColRefPic and the motion vector mvCol, which are effective prediction directions in the motion information of the candidate block. When the prediction direction of the candidate block is the unidirectional direction of the L0 direction or the L1 direction, it is selected based on the reference image and the motion vector in the prediction direction. When the prediction direction of the candidate block is bidirectional, the selection is made based on either the reference image in the L0 direction or the L1 direction and the motion vector. For example, a reference image and a motion vector that are present in the same time direction as ColPic are selected as a reference, and a candidate block is selected based on a reference image that is closer to the distance between ColPic and a reference image in the L0 direction or L1 direction of the candidate block. For example, the block may be selected based on the direction in which the motion vector in the L0 direction or the L1 direction intersects the processing target image. When a reference image and a motion vector as a reference for generating bidirectional motion information are selected, a motion vector of a temporally combined motion information candidate is calculated.

Here, the time combination motion information candidates are generated as described above, but it is only necessary to be able to determine bidirectional motion information using motion information of another encoded image, and the present invention is not limited to this. For example, a motion vector scaled according to the distance between the reference image in each direction and the processing target image as in direct motion compensation may be used as a bidirectional motion vector. If the candidate block is invalid (NO in S163), the next candidate block is inspected (S165).

Here, it is assumed that the time combination motion information candidate list includes motion information of one or less candidate blocks. However, the number of time combination motion information candidate lists may be changed depending on the effectiveness of the candidate block, and is not limited thereto. Similarly, the prediction direction, reference image, and motion vector determination method are not limited to these.

(Generation of bidirectional combined motion information candidate list)
Subsequently, the detailed operation of generating the bidirectional combined motion information candidate list will be described with reference to the flowchart of FIG. Assume that the bidirectional combined motion information candidate list is empty. The reference direction determination unit 160 determines the reference direction of the bidirectional combined motion information candidate from the second combined motion information candidate list (S170). The reference direction for the bidirectional combined motion information candidate (BD0) with the reference direction L0 is the L0 direction, and the reference direction for the bidirectional combined motion information candidate (BD1) with the reference direction L1 is the L1 direction.

The reference direction motion information determination unit 161 determines the reference direction motion vector and the reference image index of the bidirectional combined motion information candidate from the reference direction and the second combined motion information candidate list supplied from the reference direction determination unit 160 ( S171). The detailed operation of the reference direction motion information determination unit 161 will be described later.

The backward direction motion information determination unit 162 reverses the bidirectional combined motion information candidate from the reference direction, the reference direction motion vector, the reference image index, and the second combined motion information candidate list supplied from the reference direction motion information determination unit 161. A direction motion vector and a reference image index are determined (S172). The detailed operation of the backward motion information determination unit 162 will be described later.

The bidirectional motion information determination unit 163 generates bidirectional combined motion information from the reference direction, the reference direction motion vector and the reference image index, and the reverse direction motion vector and the reference image index supplied from the backward direction motion information determination unit 162. A candidate prediction direction is determined (S173). The detailed operation of determining the prediction direction of the bidirectional combined motion information candidate will be described later.

The bidirectional motion information determination unit 163 checks the validity of the prediction direction of the bidirectional combined motion information candidate (S174). If the prediction direction of the bidirectional combined motion information candidate is valid (YES in S174), the bidirectional motion information determination unit 163 adds the bidirectional combined motion information candidate to the bidirectional combined motion information candidate list (S175). If the prediction direction of the bidirectional combined motion information candidate is invalid (NO in S174), step S175 is skipped.

Subsequently, the detailed operation of the reference direction motion information determination unit 161 will be described using the flowchart of FIG. Assume that the LX direction (X is 0 or 1) is selected as the reference direction of the bidirectional combined motion information candidate. The validity of the reference direction LX is set to “0” (S190). The number of combined motion information candidates (NCands) included in the second combined motion information candidate list is repeated, and the following processing is repeated (S191 to S194). The validity of the combined motion information candidate in the LX direction is checked (S192). If the LX direction of the combined motion information candidate is valid (YES in S192), the validity of the reference direction LX is set to “1”, and the motion vector and reference index in the reference direction are set to the LX direction of the combined motion information candidate. The process ends with the motion vector and the reference index (S193). If the LX direction of the combined motion information candidate is invalid (NO in S192), the next candidate is examined (S194).

Here, it is assumed that only the number of combined motion information candidates (NCands) included in the second combined motion information candidate list is inspected, but it is sufficient that the motion information in the reference direction of the bidirectional combined motion information candidates can be determined, and the present invention is not limited to this. For example, when bi-directional combined motion information candidates are generated only from combined motion information candidates with a high selection rate, the number of inspections is fixed to a predetermined number such as 2 or 3, and the amount of processing is reduced and redundant bi-directional coupling is performed. It is also possible to reduce the amount of merge index codes by reducing the possibility of generating motion information candidates.

Subsequently, the detailed operation of the backward motion information determination unit 162 will be described using the flowchart of FIG. The reverse direction of the reference direction is set as the reverse direction of the bidirectional combined motion information candidate. It is assumed that the LY direction (Y is 0 or 1) is selected as the reverse direction. The validity of LY in the reverse direction is set to “0” (S200). The number of combined motion information candidates included in the second combined motion information candidate list (NCands) and the following processing are repeated (S201 to S205).

It is checked that it is not a combined motion information candidate selected in the reference direction (S202). If it is not the combined motion information candidate selected in the reference direction (YES in S202), the validity of the combined motion information candidate in the LY direction is checked (S203). If the LY direction of the combined motion information candidate is valid (YES in S203), the validity of the reverse LY is set to “1”, and the reverse motion vector and reference index are set to the LY direction of the combined motion information candidate. The process ends with the motion vector and the reference index (S204). If it is a combined motion information candidate selected in the reference direction (NO in S202), or if the LY direction of the combined motion information candidate is invalid (NO in S203), the next candidate is examined (S205).

Here, it is assumed that only the number of combined motion information candidates (NCands) included in the second combined motion information candidate list is inspected, but it is only necessary to be able to determine motion information in the reverse direction of the bidirectional combined motion information candidates, and the present invention is not limited to this. For example, when bi-directional combined motion information candidates are generated only from combined motion information candidates with a high selection rate, the number of inspections is fixed to a predetermined number such as 2 or 3, and the amount of processing is reduced and redundant bi-directional coupling is performed. It is also possible to reduce the amount of merge index codes by reducing the possibility of generating motion information candidates. In addition, by setting the block to start the inspection as the combined motion information candidate next to the combined motion information candidate selected in the reference direction, the possibility that BD0 and BD1 are the same can be eliminated, and step S202 can be reduced. .

Subsequently, the detailed operation of determining the prediction direction of the bidirectional combined motion information candidate will be described using the table of FIG. If both the LX direction and the LY direction are valid, the prediction direction is a bi-directional BI. If only the LX direction is valid, the prediction direction is a unidirectional LX direction. If only the LY direction is valid, the prediction direction is a single direction. The prediction direction becomes invalid if both the LX direction and the LY direction are invalid. That is, when both the LX direction and the LY direction are valid, a combined motion information candidate having motion information in the LX direction and a combined motion information candidate having motion information in the LX direction having motion information in the LY direction A new bidirectional combined motion information candidate is generated by combining with another combined motion information candidate. In addition, when only the LX direction is valid, if the prediction direction of the combined motion information candidate having the effective LX prediction is bi-prediction, the prediction direction of the combined motion information candidate is converted to single prediction. Become. Similarly, when only the LY direction is valid, if the prediction direction of the combined motion information candidate having the effective LY prediction is bi-prediction, the prediction direction of the combined motion information candidate is converted to single prediction. become.

Here, the determination of the prediction direction of the bidirectional combined motion information candidate is shown in FIG. 30, but it is only necessary to be able to determine the prediction direction, and the present invention is not limited to this. FIGS. 31 (a) to 31 (c) show an extended example of determining the prediction direction of the bidirectional combined motion information candidate. For example, if at least one of the LX direction and the LY direction is invalid as shown in FIG. 31A, the prediction direction is invalidated, or the prediction direction is forced as shown in FIGS. 31B and 31C. Alternatively, it may be bidirectional.

Generally, when the accuracy of motion vectors is relatively high, the prediction efficiency of bidirectional prediction is higher than that of unidirectional prediction. Therefore, in FIG. 31A, when both the LX direction and the LY direction are not valid, the prediction direction of the bidirectional combined motion information candidates is invalidated, and the number of combined motion information candidates is reduced to reduce the code amount of the merge index. Can be reduced. Here, for example, when there is a bidirectional prediction candidate among the unidirectional combined motion information candidates, the adaptive processing may be performed so as to invalidate the prediction direction of the bidirectional combined motion information candidate.

Further, in FIG. 31B, the motion vector in the invalid prediction direction is (0, 0) and the reference index is “0”. In this way, the bidirectional combined motion information candidate can be forced to be bidirectional using the reference image of the shortest distance as a prediction signal. This is because the reference index “0” is generally the reference image closest to the processing target image, and the reliability of the prediction signal with the shortest distance is the highest.

(Configuration of moving picture decoding apparatus 200)
Next, the moving picture decoding apparatus according to the first embodiment will be described. FIG. 32 shows a moving picture decoding apparatus 200 according to the first embodiment. The video decoding device 200 is a device that generates a playback image by decoding the code string encoded by the video encoding device 100.

The video decoding device 200 is realized by hardware such as an information processing device 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 position information and the prediction block size of the prediction block to be decoded are shared in the video decoding device 200 and are not shown. Further, the maximum number of combined motion information candidates included in the candidate number management table and the combined motion information candidate list is assumed to be shared in the moving image decoding apparatus 200 and is 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.

(Function of moving picture decoding apparatus 200)
Hereinafter, functions of each unit will be described. The code string analysis unit 201 decodes the code string supplied from the terminal 30 to predict prediction error encoded data, merge flag, merge candidate number, prediction direction of motion compensation prediction, reference image index, difference vector, and prediction vector index. Is decoded according to the syntax. Then, the prediction error coding data is transferred to the prediction error decoding unit 202, the merge flag, the merge candidate number, the prediction direction of the motion compensation prediction, the reference image index, the difference vector, and the prediction vector index as motion information. This is supplied to the playback unit 204. The merge candidate number is obtained by conversion from the merge index.

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

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

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 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 that characterizes the first embodiment will be described with reference to FIG. FIG. 33 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, and the terminal 34 is connected to the motion compensation unit 205.

The functions of each part are described below. If the merge flag supplied from the code stream analysis unit 201 is “0”, the coding mode determination unit 210 determines the prediction direction, reference image index, difference vector, motion compensation prediction supplied from the code stream analysis unit 201, The prediction vector index is supplied to the motion vector reproduction unit 211. If the merge flag is “1”, the merge candidate number supplied from the code string analysis unit 201 is supplied to the combined motion information reproduction unit 212.

The motion vector reproduction unit 211 receives motion information from the prediction direction of motion compensation prediction supplied from the encoding mode determination unit 210, the reference image index, the difference vector, and the prediction vector index, and the candidate block group supplied from the terminal 33. Is supplied to the terminal 34. A detailed configuration of the motion vector reproducing unit 211 will be described later.

The combined motion information reproduction unit 212 reproduces the motion information from the merge candidate number supplied from the encoding mode determination unit 210 and the candidate block group supplied from the terminal 33 and supplies the motion information to the terminal 34. A detailed configuration of the combined motion information reproducing unit 212 will be described later.

Subsequently, a detailed configuration of the motion vector reproducing unit 211 will be described with reference to FIG. FIG. 34 shows the configuration of the motion vector reproducing unit 211. The motion vector reproduction unit 211 includes a prediction vector candidate list generation unit 220, a prediction vector determination unit 221, and an addition unit 222. The terminal 35 is connected to the encoding mode determination unit 210.

The functions of each part are described below. The prediction vector candidate list generation unit 220 has the same function as the prediction vector candidate list generation unit 130 of the video encoding device 100. The prediction vector determination unit 221 determines a prediction vector from the prediction vector candidate list supplied from the prediction vector candidate list generation unit 220 and the prediction vector index supplied from the terminal 35, and supplies the prediction vector to the addition unit 222.

The addition unit 222 adds the difference vector supplied from the terminal 35 and the prediction vector supplied from the prediction vector determination unit 221 to calculate a motion vector, and supplies the motion vector to the terminal 34.

Subsequently, a detailed configuration of the combined motion information reproducing unit 212 will be described with reference to FIG. FIG. 35 shows the configuration of the combined motion information playback unit 212. The combined motion information reproduction unit 212 includes a combined motion information candidate generation unit 230 and a combined motion information selection unit 231.

The function of each part will be described below. The combined motion information candidate generation unit 230 has the same function as the combined motion information candidate generation unit 140 shown in FIG. Based on the combined motion information candidate list supplied from the combined motion information candidate generation unit 230 and the merge candidate number supplied from the terminal 35, the combined motion information selection unit 231 selects motion information from the combined motion information candidate list. The motion information is selected and supplied to the terminal 34.

(Operation of the video decoding device 200)
Subsequently, the decoding operation in the moving picture decoding apparatus 200 according to Embodiment 1 will be described with reference to the flowchart of FIG. The code string analysis unit 201 decodes the code string supplied from the terminal 30 to predict prediction error encoded data, merge flag, merge candidate number, prediction direction of motion compensation prediction, reference image index, difference vector, and prediction vector index. Is decoded according to the syntax (S210).

The motion information reproduction unit 204 is supplied from the motion information memory 207 and the merge flag, merge candidate number, motion compensation prediction direction, reference image index, difference vector, and prediction vector index supplied from the code string analysis unit 201. Motion information is reproduced from the candidate block group (S211).

The motion compensation unit 205 performs motion compensation on the reference image indicated by the reference image index in the frame memory 206 based on the motion information supplied from the motion information reproduction unit 204, and generates a prediction signal. If the prediction direction is bidirectional, an average of the prediction signals in the L0 direction and the L1 direction is generated as a prediction signal (S212).

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 (S213). 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 (S214).

The frame memory 206 stores the decoded image signal supplied from the adding unit 203 (S215). The motion information memory 207 stores the motion vector supplied from the motion information reproducing unit 204 for one image in the minimum predicted block size unit (S216).

Subsequently, the operation of the motion information reproducing unit 204 will be described using the flowchart of FIG. The encoding mode determination unit 210 determines whether the merge flag supplied from the code string analysis unit 201 is “0” or “1” (S220). If the merge flag is “1” (1 in S220), the combined motion information reproduction unit 212 calculates the motion from the merge candidate number supplied from the encoding mode determination unit 210 and the candidate block group supplied from the terminal 33. Information is reproduced (S221).

If the merge flag is “0” (0 in S220), the motion vector reproduction unit 211 supplies the motion compensation prediction prediction direction, reference image index, difference vector, and prediction vector supplied from the coding mode determination unit 210. Motion information is reproduced from the index and the candidate block group supplied from the terminal 33 (S222).

Subsequently, the operation of the motion vector reproducing unit 211 will be described using the flowchart of FIG. The prediction vector candidate list generation unit 220 generates a prediction vector candidate list by the same operation as the prediction vector candidate list generation unit 130 of the video encoding device 100 (S300).

The prediction vector determination unit 221 selects a prediction vector candidate indicated by the prediction vector index supplied from the terminal 35 from the prediction vector candidate list supplied from the prediction vector candidate list generation unit 220, and determines a prediction vector. (S301). The adder 222 adds the difference vector supplied from the terminal 35 and the prediction vector supplied from the prediction vector determination unit 221 to calculate a motion vector (S302).

Subsequently, the operation of the combined motion information reproduction unit 212 will be described using the flowchart of FIG. The combined motion information candidate generation unit 230 generates a combined motion information candidate list by the same operation as the combined motion information candidate generation unit 140 of the video encoding device 100 (S310). The combined motion information selection unit 231 selects a combined motion information candidate indicated by the merge candidate number supplied from the terminal 35 from the combined motion information candidate list supplied from the combined motion information candidate generation unit 230, and combines them. The motion information is determined (S311).

(Modification of Embodiment 1)
The first embodiment can be modified as follows.

(Variation 1: Merge candidate number order)

In Embodiment 1 described above, FIG. 18 is given as an example of the candidate number management table. However, the maximum number of combined motion information candidates may be 1 or more, and a merge candidate number with a smaller combined motion information candidate with a higher selection rate. Is not limited to that shown in FIG. The maximum number of combined motion information candidates included in the combined motion information candidate list is 7 (the maximum value of the merge index is 6), but it may be 2 or more. For example, when the selection rate of bidirectional combined motion information candidates is higher than the selection rate of combined motion information candidates of block C and block E, it may be as shown in FIGS. 40 (a) and 40 (b). .

Also, as shown in FIG. 41, the number of bidirectional combined motion information candidates can be increased. Each bidirectional combined motion information candidate (BD0 to BD3) will be described. The bidirectional combined motion information candidate (BD0) and the bidirectional combined motion information candidate (BD1) are assumed to be the same as those in the first embodiment. The bidirectional combined motion information candidate (BD2) and the bidirectional combined motion information candidate (BD3) include a reference direction motion vector and a reference index of the reference direction bidirectional combined motion information candidate, and a reverse bidirectional combined motion information candidate. The method of determining the motion vector and reference index in the base direction is different between the bidirectional combined motion information candidate (BD0) and the bidirectional combined motion information candidate (BD1).

FIG. 42 is a flowchart for explaining the derivation of the bidirectional combined motion information candidate (BD2). FIG. 42 is obtained by replacing step S193 in the flowchart of FIG. 28 from step S195 to step S197. Hereinafter, step S195 to step S197 will be described. It is checked whether the effectiveness of LX is “1” (S195). If the validity of LX is not “1” (NO in S195), the validity of LX is set to “1” (S196), and the next candidate is examined (S194). If the validity of LX is “1” (YES in S195), the motion vector and reference index in the base direction are set as the motion vector and reference index in the LX direction of the combined motion information candidate (S197), and the process ends.

FIG. 43 is a flowchart for explaining the derivation of the bidirectional combined motion information candidate (BD3). FIG. 43 is obtained by replacing step S204 in the flowchart of FIG. 29 from step S206 to step S208. Hereinafter, step S206 to step S208 will be described. Whether the validity of LY is “1” is checked (S206). If the validity of LY is not “1” (NO in S206), the validity of LY is set to “1” (S207), and the next candidate is examined (S205). If the validity of LY is “1” (YES in S206), the motion vector and reference index in the base direction are set as the motion vector and reference index in the LY direction of the combined motion information candidate (S208), and the process is terminated.

That is, the bidirectional combined motion information candidate (BD2) is first effective when it is not the same candidate as the reference direction in the reverse direction, and the motion vector and reference index in the reference direction of the combined motion information candidate that is second effective in the reference direction. The combined motion information candidate is a bidirectional combined motion information candidate using a motion vector in the reverse direction of the combined motion information candidate and a reference index.

In addition, the bidirectional combined motion information candidate (BD3) is the second effective that is not the same candidate as the reference direction in the reverse direction and the motion vector and reference index in the reference direction of the combined motion information candidate that is first effective in the reference direction. The combined motion information candidate is a bidirectional combined motion information candidate that combines a motion vector in the reverse direction of the combined motion information candidate and a reference index.

As described above, the number of combinations of bidirectional combined motion information candidates can be increased, the selection rate of combined motion information candidates can be increased, and the encoding efficiency of motion information can be improved.

(Modification 2: Same determination of bidirectional combined motion information candidates)
In Embodiment 1 described above, FIG. 29 is given as an example of the operation of the backward direction motion information determination unit 162, but it is only necessary to generate bidirectional combined motion information candidates, and the present invention is not limited to this. For example, step S240 may be added as shown in FIG. 44 in order to increase the effectiveness of the bidirectional combined motion information candidate, that is, to prevent the second combined motion information candidate list reduction unit 153 from deleting it.

The combined motion information candidate having the same motion information as the bidirectional combined motion information candidate using the motion vector and reference index in the reference direction and the backward motion vector and reference index of the combined motion information candidate to be inspected is the second It is inspected that it is not in the combined motion information candidate list (S240). When the same combined motion information candidate does not exist (YES in S240), step S205 is performed. When the same combined motion information candidate exists (NO in S240), the next candidate is examined (S206). In this case, the second combined motion information candidate list reduction unit 153 in FIG. 16 and step S146 in FIG. 24 can be omitted.

Accordingly, the second combined motion information candidate list reduction unit 153 does not reduce the bidirectional combined motion information candidates, and the selection rate of the combined motion information candidates can be increased and the motion information encoding efficiency can be improved. .

(Variation 3: Same determination with reference direction of bidirectional combined motion information candidate)
In Embodiment 1 described above, FIG. 29 is given as an example of the operation of the backward direction motion information determination unit 162, but step S250 may be added as shown in FIG.

It is checked that the backward motion vector and reference index of the combined motion information candidate selected in the reference direction are not the same as the backward motion vector and reference index of the combined motion information candidate to be inspected (S250). If they are not identical (YES in S250), step S205 is performed. If they are the same (NO in S250), the next candidate is inspected (S206).

As a result, the bidirectional combined motion information candidate is not the same as the combined motion information candidate selected in the reference direction, and the effectiveness of the bidirectional combined motion information candidate is increased and the combined motion information candidate selection rate is increased. Thus, the encoding efficiency of motion information can be improved.

(Modification 4: Unification of deletion process)
In Embodiment 1 described above, FIG. 16 is given as an example of the configuration of the combined motion information candidate generation unit 140. However, as a simpler configuration, the first combined motion information candidate list reduction unit 151 is configured as illustrated in FIG. Alternatively, only the second combined motion information candidate list reduction unit 153 can be combined with the deletion unit.

However, since a redundant combined motion information candidate is supplied to the bidirectional combined motion information candidate list generation unit 152 as a problem in this case, if the first two unidirectional combined motion information candidates are the same, the reference The bidirectional combined motion information candidate (BD0) whose direction is L0 and the bidirectional combined motion information candidate (BD1) whose reference direction is L1 are the same motion information. Therefore, as shown in FIG. 47 (b), the probability of generating the same bidirectional combined motion information candidate by changing the inspection order of FIG. 28 and FIG. 29 depending on whether the reference direction is L0 or L1. Can be reduced.

(Modification 5: Use in the same direction)
In Embodiment 1 described above, regarding the reverse direction of the reverse direction motion information determination unit 162, if the reference direction is the L0 direction, the reverse direction is the L1 direction, and if the reference direction is the L1 direction, the reverse direction is the L0 direction. An example was given. In this regard, if the reference direction is the L0 direction, the reverse direction may be the L0 direction, and if the reference direction is the L1 direction, the reverse direction may be the L1 direction. As shown in FIG. 48, when only the motion information in the same prediction direction exists in the combined motion information candidates included in the second combined motion information candidate list, the generation probability of the bidirectional combined motion information candidate is increased. The efficiency of encoding motion information can be improved by increasing the selection rate of information candidates.

(Modification 6: predetermined combination)
In the first embodiment described above, bidirectional combined motion information candidates are generated by searching for combined motion information candidate blocks that are valid in the direction opposite to the reference direction and using the motion information in the direction opposite to the reference direction. . By searching in the direction opposite to the reference direction, the effectiveness of the bidirectional combined motion information candidate can be improved, but the processing amount increases.

Therefore, as shown in FIGS. 49 (a) and 49 (b), the bidirectional combined motion information candidates are defined as combinations of predetermined combined motion information candidate blocks with higher reliability, thereby omitting the search process. It is possible to improve the coding efficiency by improving the selection rate of the directional coupled motion information candidates.

In FIG. 49A, the bidirectional combined motion information candidate (BD0) having the reference direction L0 indicates the motion information in the L0 direction of the candidate block A with the highest reliability and the L1 direction of the candidate block B with the second highest reliability. Combining the motion information, the bi-directional combined motion information candidate (BD1) whose reference direction is L1 is the motion information in the L1 direction of the most reliable candidate block A and the L0 direction of the second most reliable candidate block B in the L0 direction. This is an example in which motion information is combined and the prediction direction is defined as bidirectional prediction.

In FIG. 49B, the bidirectional combined motion information candidate (BD0) whose reference direction is L0 is the motion information in the L0 direction of the candidate block A having the highest reliability, and the bidirectional combined motion information candidate (BD1) whose reference direction is L1. ) As the motion information in the L1 direction of the candidate block A with the highest reliability, and the prediction direction is defined as unidirectional prediction. Note that other combinations are possible as long as the combinations of candidate blocks have higher reliability.

(Modification 7: BD0, BD1 adaptation)
In Embodiment 1 described above, a small merge candidate number is assigned to the bidirectional combined motion information candidate (BD0) whose reference direction is L0. However, the present invention is not limited to this. For example, by assigning a small merge candidate number preferentially to a bidirectional combined motion information candidate whose prediction direction is bidirectional, a small merge candidate number is assigned to a bidirectional combined motion information candidate for bidirectional prediction with high prediction efficiency. The encoding efficiency can also be improved. Further, when both BD0 and BD1 are bidirectional prediction, a smaller merge candidate number can be preferentially assigned to a bidirectional combined motion information candidate whose motion information in the reference direction is unidirectional. This is because the reliability of motion information is generally high when unidirectional prediction is selected even though bidirectional prediction has higher prediction efficiency than unidirectional prediction.

(Effect of Embodiment 1)
(Example of the effect of bidirectional joint motion information in bidirectional prediction)
The effect by Embodiment 1 is demonstrated using FIG. Hereinafter, the motion vector in the L0 direction of the block N is mvL0N, the motion vector in the L1 direction is mvL1N, the reference image index in the L0 direction is refIdxL0N, the reference image index in the L1 direction is refIdxL1N, the difference vector in the L0 direction is dmvL0N, and in the L1 direction The difference vector is represented as dmvL1N, the difference between the reference image indexes in the L0 direction is represented as drefIdxL0N, and the reference image index in the L1 direction is represented as drefIdxL1N.

The motion information with the smallest prediction error for the processing target block (Z) is that the prediction direction is bidirectional (BI), mvL0Z = (2,8), mvL1Z = (4,2), refIdxL0Z = 0, refIdxL1N = 0 Suppose that

Suppose that the unidirectional combined motion information candidates are A, B, COL, C, and E in FIG. Among these unidirectional combined motion information candidates, there is no motion information identical to the motion information that minimizes the prediction error for the processing target block (Z). Therefore, a unidirectional combined motion information candidate having a minimum rate distortion evaluation value is selected from these unidirectional combined motion information candidates. Then, the candidate rate distortion evaluation value and the rate distortion evaluation value calculated by the difference vector calculation unit 120 are compared, and the merge mode is used as the encoding mode only when the former is smaller than the latter. Become.

When the merge mode is selected as the encoding mode, it is because the balance between the encoding efficiency of motion information and the prediction error is optimal, and the prediction error is not optimal. On the other hand, when the non-merge mode is selected as the encoding mode, the encoding efficiency of motion information is not optimal.

Here, the bidirectional combined motion information candidates generated by the first embodiment are BD0 and BD1 in FIG. The bidirectional combined motion information candidate (BD0) whose reference direction is L0 is a bidirectional combined motion information candidate including the motion information of the block A in the L0 direction and the motion information of the block B in the L1 direction. The bidirectional combined motion information candidate (BD1) having the reference direction L1 is a bidirectional combined motion information candidate including the motion information of the block A in the L1 direction and the motion information of the block B in the L0 direction. At this time, it can be seen that the bidirectional combined motion information candidate (BD0) whose reference direction is L0 has the same motion information as the motion information that minimizes the prediction error for the processing target block (Z). That is, by selecting the bidirectional combined motion information candidate (BD0) whose reference direction is L0, it is possible to minimize the prediction error and optimize the encoding efficiency of the motion information.

(Effects of bidirectional combined motion information for unidirectional prediction)
Moreover, the effect of the unidirectional prediction by Embodiment 1 is demonstrated using FIG. It is assumed that the motion information that minimizes the prediction error for the processing target block (Z) is unidirectional (UNI), mvL0Z = (0,8), and refIdxL0Z = 2.

Suppose B, C, and COL of unidirectional combined motion information candidates are invalid (x), and valid unidirectional combined motion information candidates A and E have motion information as shown in FIG. Also in this case, there is no motion information in the unidirectional combined motion information candidates that minimizes the prediction error for the processing target block (Z).

Also here, the bidirectional combined motion information candidates generated by the first embodiment are BD0 and BD1 in FIG. The bidirectional combined motion information candidate (BD0) whose reference direction is L0 is a bidirectional combined motion information candidate whose prediction direction consisting of motion information of the block A in the L0 direction is unidirectional. The bidirectional combined motion information candidate (BD1) whose reference direction is L1 is a bidirectional combined motion information candidate including the motion information of the block E in the L0 direction and the motion information of the block A in the L1 direction. It can be seen that the bidirectional combined motion information candidate (BD0) whose reference direction is L0 has the same motion information as the motion information that minimizes the prediction error for the processing target block (Z). That is, by selecting the bidirectional combined motion information candidate (BD0) whose reference direction is L0, it is possible to minimize the prediction error and optimize the encoding efficiency of the motion information.

(Effect of bidirectional joint motion information by combination of unidirectional prediction)
Further, the effect of the combination of motion information in which the prediction direction is unidirectional according to Embodiment 1 will be described with reference to FIG. The motion information with the smallest prediction error for the processing target block (Z) is that the prediction direction is unidirectional (BI), mvL0Z = (2, 2), refIdxL0Z = 0, mvL1Z = (− 2, 2), refIdxL1Z = Assume that it is zero.

Suppose that unidirectional combined motion information candidates A, COL, and C are invalid (x), and valid unidirectional combined motion information candidates B and E have motion information as shown in FIG. Also in this case, there is no motion information in the unidirectional combined motion information candidate that minimizes the prediction error for the processing target block (Z).

Also here, the bidirectional combined motion information candidates generated by the first embodiment are BD0 and BD1 in FIG. The bidirectional combined motion information candidate (BD0) whose reference direction is L0 is a bidirectional combined motion information candidate including the motion information of the block B in the L0 direction and the motion information of the block E in the L1 direction, and BD1 is not generated. It can be seen that the bidirectional combined motion information candidate (BD0) having the reference direction L0 has the same motion information as the motion information that minimizes the prediction error for the processing target block (Z). That is, by selecting the bidirectional combined motion information candidate (BD0) whose reference direction is L0, it is possible to minimize the prediction error and optimize the encoding efficiency of the motion information.

(Bidirectional motion information candidate)
As described above, by generating the bidirectional combined motion information candidate using the motion information in the L0 direction and the L1 direction of the unidirectional combined motion information candidate, the motion of the processing target block is encoded with another image. Even if there is a deviation from the motion of the block located at the same position or the adjacent block of the processing target block, the motion information can be encoded using only the index without encoding. Therefore, it is possible to realize a moving image encoding device and a moving image decoding device that can optimize encoding efficiency and prediction efficiency.

(Candidate motion information in one direction)
Also, when generating new unidirectional combined motion information candidates using the unidirectional combined motion information candidate L0 direction and L1 direction motion information, the unidirectional combined motion information candidate L0 direction and L1 direction are also generated. The same effect as the case where the bidirectional combined motion information candidate is generated using the motion information is obtained.

(Bidirectional motion information by using the same direction)
Also, in the case of generating a bidirectional combined motion information candidate using motion information in the same prediction direction of the unidirectional combined motion information candidate, the motion information in the L0 direction and the L1 direction of the unidirectional combined motion information candidate is used. As a result, the same effect is produced as in the case of generating bidirectional combined motion information candidates.

(Simplified video decoding process)
As described above, by generating the bidirectional combined motion information candidate using the motion information in each direction of the unidirectional combined motion information candidate, the motion of the block to be processed is the same position in another encoded image. Even when there is a deviation from the motion of the block or the adjacent block of the processing target block, decoding of the prediction direction, the reference index and the difference vector, addition processing of the prediction vector and the difference vector, etc. are not required, Can be reduced.

(Deletion process)
As described above, by installing the first combined motion information candidate list reduction unit 151, the bidirectional combined motion information candidate list generation unit 152 has the bidirectional combined motion information candidate (BD 0) whose reference direction is L 0 and the reference It can be avoided that the bidirectional combined motion information candidate (BD1) having the direction L1 has the same motion information, and the effectiveness of the bidirectional combined motion information candidate can be increased to improve the encoding efficiency.

(Merge candidate number assignment in order of selectivity)
As described above, by assigning a smaller merge candidate number to a combined motion information candidate with a higher selection rate, the selection rate of more reliable motion information in each direction is increased, and highly accurate motion information is used in each direction. Highly accurate bi-directional joint motion information candidates can be generated. In addition, the search process can be simplified, and a reduction in encoding efficiency can be suppressed even if the number of search processes is limited.

(Memory lead time)
As described above, the combined motion information candidates are generated without increasing the number of unidirectional combined motion information candidates by generating the bidirectional combined motion information candidates using the motion information in each direction of the unidirectional combined motion information candidates. The number of can be increased. Therefore, in the moving picture encoding apparatus and moving picture decoding apparatus using a general LSI in which the memory read time is increased by increasing the number of unidirectional combined motion information candidates, the number of unidirectional combined motion information candidates is increased. The increase in memory read time due to can be suppressed.

(Adaptive switching)
As described above, by assigning a small merge candidate number to a bidirectional combined motion information candidate whose prediction direction is bidirectional, a bidirectional combined motion information candidate having a high prediction efficiency and a bidirectional prediction direction can be obtained. By increasing the selection rate and preferentially assigning a small merge candidate number to a bidirectional combined motion information candidate whose motion information in the reference direction is unidirectional, a bidirectional combined motion information candidate using highly reliable motion information It is possible to improve the coding efficiency by increasing the selectivity.

[Embodiment 2]
(Syntax)
The configuration of the moving image encoding apparatus according to the second embodiment is the same as that of the moving image encoding apparatus 100 according to the first embodiment except for the higher-order function of the moving image encoding apparatus and the function of the code string generation unit 104. is there. Hereinafter, differences between the higher-order function of the moving picture coding apparatus and the function of the code string generation unit 104 in the second embodiment from those in the first embodiment will be described.

The higher-order function of the moving picture encoding apparatus according to the second embodiment has a function of changing the candidate number management table for each encoded stream unit or for each slice that is a part of the encoded stream. The code string generation unit 104 encodes the candidate number management table into an encoded stream as shown in FIGS. 53 (a) and 53 (b) and transmits the encoded stream. 53 (a) and 53 (b), the syntax of encoding the candidate number management table with SPS (Sequence Parameter Set) for control in units of encoded streams and Slice_header for control in units of slices. An example is shown.

"modified_merge_index_flag" specifies whether to change the standard relationship between the merge candidate number and the combined motion information candidate, specifies the number to be redefined with "max_no_of_merge_index_minus1", and enters the combined motion information candidate list with "merge_mode [i]" Specifies the order of candidate blocks included. In addition, “bd_merge_base_direction” that is information for designating the reference direction of the bidirectional combined motion information candidate can be set.

For example, if the standard relationship between the merge candidate number and the combined motion information candidate is FIG. 18 and the candidate number management table to be redefined is FIG. 40A, “modified_merge_index_flag” is set to “1”, “ “max_no_of_merge_index_minus1” is set to “6”, and “merge_mode [i]” is set to “0”, “1”, “2”, “5”, “6”, “3”, and “4”, respectively.

53 (a) and 53 (b) are examples of syntax, and merge candidate numbers to be assigned to bidirectional combined motion information candidates can be specified in the encoded stream, and the reference direction of bidirectional combined motion information candidates can be determined. However, the present invention is not limited to this.

The configuration of the moving picture decoding apparatus according to the second embodiment is the same as that of the moving picture decoding apparatus 200 according to the first embodiment except for the function of the code string analysis unit 201. Hereinafter, the difference of the function of the code string analysis unit 201 of the video decoding device in the second embodiment from the first embodiment will be described. The code string analysis unit 201 decodes the candidate number management table according to the syntaxes of FIGS. 53 (a) and 53 (b).

(Effect of Embodiment 2)
The optimal relationship between the merge candidate number and the combined motion information candidate is shared by the video encoding device and the video decoding device according to Embodiment 2 in units of streams or slices, so that motion characteristics in units of streams or slices are obtained. In such a case, the coding efficiency of the merge index can be improved.

[Embodiment 3]
(Replacement of combined motion information candidates)
The configuration of the moving picture coding apparatus according to the third embodiment is the same as that of the moving picture coding apparatus 100 according to the first embodiment except for the function of the combined motion information candidate generation unit 140. First, the candidate number management table in Embodiment 3 is shown in FIG. 54, and the maximum number of combined motion information candidates included in the combined motion information candidate list is 5. The difference is that the maximum number of combined motion information candidates included in the combined motion information candidate list is 5, and no merge candidate number is assigned to the bidirectional combined motion information candidate. Hereinafter, the difference between the combined motion information candidate generation unit 140 in Embodiment 3 and Embodiment 1 will be described with reference to FIG.

55 is a configuration in which a candidate number management table changing unit 154 is added to the combined motion information candidate generating unit 140 in FIG. Hereinafter, the function of the candidate number management table changing unit 154 will be described. The candidate number management table changing unit 154 calculates the effective number of bidirectional combined motion information candidates from the second combined motion information candidate list supplied from the first combined motion information candidate list reducing unit 151. If the effective number of bidirectional combined motion information candidates is 1 or more, the candidate number management table is changed, and the second combined motion information candidate list is supplied to the bidirectional combined motion information candidate list generation unit 152. If the effective number of bidirectional combined motion information candidates is 0, the second combined motion information candidate list is supplied to the terminal 18 as a combined motion information candidate list.

Subsequently, the operation of the combined motion information candidate generation unit 140 according to the third embodiment will be described with reference to FIG. 56 and the difference from the first embodiment. The flowchart of FIG. 56 has the following two steps added to the flowchart of FIG. The candidate number management table changing unit 154 changes the candidate number management table (S260). It is checked whether the candidate number management table has been changed (S261). If the candidate number management table is changed (YES in S261), step S144 is performed. If the candidate number management table has not been changed (NO in S261), step S144 is skipped.

Hereinafter, the operation of the candidate number management table changing unit 154 will be described with reference to FIG. First, the candidate number management table changing unit 154 counts the number of invalid combined motion information candidates not included in the second combined motion information candidate list, and calculates the invalid number of combined motion information candidates (S270). In Embodiment 3, the invalid number of combined motion information candidates is calculated as the number of invalid combined motion information candidates not included in the second combined motion information candidate list. However, the number of invalid combined motion information candidates is What is necessary is just to be able to calculate, and it is not limited to this. For example, the number of valid combined motion information candidates included in the second combined motion information candidate list is subtracted from 5 which is the sum of 4 which is the maximum number of spatially combined motion information candidates and 1 which is the maximum number of temporally combined motion information candidates. Thus, the number of invalid combined motion information candidates may be obtained. In addition, when the combined motion information having a high selection rate is invalid, it is considered that the selection rate of the bidirectional combined motion information candidate also decreases. Therefore, the number of invalid combined motion information candidates having a merge candidate number of 2 or more is set. You may count.

The candidate number management table changing unit 154 checks whether the invalid number of combined motion information candidates is 1 or more (S271). If the invalid number of combined motion information candidates is 1 or more (YES in S271), the subsequent processing is performed to change the candidate number management table. If the invalid number of combined motion information candidates is 0 (NO in S271), the process ends.

The candidate number management table changing unit 154 counts the number of effective bidirectional combined motion information candidates and calculates the effective number of bidirectional combined motion information candidates (S272). That is, if both BD0 and BD1 are valid, the effective number of bidirectional combined motion information candidates is 2, and if either BD0 or BD1 is valid, the effective number of bidirectional combined motion information candidates is 1, and BD0 And BD1 are both invalid, the effective number of bidirectional combined motion information candidates is zero.

The candidate number management table changing unit 154 sets the smaller one of the invalid number of combined motion information candidates and the effective number of bidirectional combined motion information candidates as the additional number of bidirectional combined motion information candidates (S273). The candidate number management table changing unit 154 assigns invalid merge candidate numbers to the bidirectional combined motion information candidates for the added number of bidirectional combined motion information candidates (S274).

Hereinafter, an example of changing the candidate number management table of the candidate number management table changing unit 154 will be described with reference to FIGS. 58 (a) to 58 (c). FIG. 58A shows an example in which the invalid number of combined motion information candidates is 1 and the effective number of bidirectional combined motion information candidates is 1 or more. BD0 is assigned to the first invalid merge candidate number 1. If BD1 is valid, BD1 may be assigned. FIG. 58B shows an example in which the invalid number of combined motion information candidates is 2 and the effective number of bidirectional combined motion information candidates is 2. BD0 is assigned to the first invalid merge candidate number 2, and BD1 is assigned to the second invalid merge candidate number 4. FIG. 58C shows an example in which the invalid number of combined motion information candidates is 2 and the effective number of bidirectional combined motion information candidates is 1 (BD1 is valid). First, BD1 is assigned to invalid merge candidate number 2.

The configuration of the moving picture decoding apparatus according to the third embodiment is the same as that of the moving picture decoding apparatus 200 according to the first embodiment except for the function of the combined motion information candidate generation unit 140. The combined motion information candidate generation unit 140 of the video decoding device of the third embodiment is the same as the combined motion information candidate generation unit 140 of the video encoding device of the third embodiment.

(Modification of Embodiment 3)
The third embodiment can be modified as follows.

(Modification 1: Unidirectional combined motion information candidate priority)
In the above-described third embodiment, FIG. 57 is given as an example of the operation of the candidate number management table changing unit 154. However, a merge candidate number smaller in the combined motion information candidate having a higher selection rate is assigned to the changed candidate number management table. However, the present invention is not limited to this.

For example, when the reliability of an existing unidirectional combined motion information candidate is sufficiently high, the following step S275 may be added to the operation of the candidate number management table changing unit 154 as shown in FIG. The flowchart of FIG. 59 is obtained by adding step S275 to the flowchart of FIG. The candidate number management table changing unit 154 packs the merge candidate numbers of invalid combined motion information candidates (S274).

Hereinafter, an example of changing the candidate number management table of the candidate number management table changing unit 154 will be described with reference to FIGS. 60 (a) and 60 (b). FIG. 60A shows an example in which the invalid number of combined motion information candidates is 1 and the effective number of bidirectional combined motion information candidates is 1 or more. After the invalid merge candidate number (merge candidate number 1) is filled, BD0 is first assigned to the invalid merge candidate number 4. If BD1 is valid, BD1 may be assigned. FIG. 60B shows an example in which the invalid number of combined motion information candidates is 2 and the effective number of bidirectional combined motion information candidates is 2. After the invalid merge candidate number (merge candidate number 2) is filled, BD0 is assigned to the first invalid merge candidate number 3, and BD1 is assigned to the second invalid merge candidate number 4. Thus, a merge candidate number larger than that of the unidirectional combined motion information candidate is assigned to the bidirectional combined motion information candidate.

(Modification 2: Depends on a predetermined block)
The operation of the candidate number management table changing unit 154 can be further modified. First, in this modification, it is assumed that a predetermined bidirectional combined motion information candidate is associated with a predetermined block, BD0 is associated with block C, and BD1 is associated with block D. Hereinafter, another modification of the operation of the candidate number management table changing unit 154 will be described with reference to FIG. The following process is repeated for the number of associated blocks (S280 to S284). Whether the i-th predetermined block is invalid is checked (S281). If the i-th predetermined block is invalid (YES in S281), the subsequent processing is performed to change the candidate number management table. If the i-th predetermined block is not invalid (NO in S281), the next predetermined block is inspected.

In Modification 2, it is assumed that there are two predetermined combined motion information candidates, that is, block C with merge candidate number 3 and block E with merge candidate number 4. Therefore, the candidate number management table changing unit 154 assigns the bidirectional combined motion information candidate (BD0) to the first predetermined invalid merge candidate number, and the candidate number management table changing unit 154 sets the second predetermined invalid invalid candidate number. A bidirectional combined motion information candidate (BD1) is assigned to the merge candidate number (S282).

As described above, the bidirectional combined motion information candidate list generation unit 152 according to the modified example 2 is valid when the predetermined combined motion information candidate is invalid. Here, the predetermined combined motion information candidates are the block C and the block E, but when the combined motion information candidate having a higher merge candidate number and the low selection rate is invalid, the bidirectional combined motion information candidate is generated. However, the present invention is not limited to this.

(Variation 3: Replacement of combined motion information candidates for unidirectional prediction)
The operation of the candidate number management table changing unit 154 can be further modified. Hereinafter, a modified example of the operation of the candidate number management table changing unit 154 will be described with reference to FIG. If the invalid number of combined motion information candidates is 0 (NO in S271), the candidate number management table changing unit 154 indicates that the prediction direction included in the second combined motion information candidate list is unidirectional (L0 direction or L1 direction). The number of combined motion information candidates is counted, and the number of unidirectional predictions is calculated (S290). It is investigated whether the number of unidirectional predictions is 1 or more (S291). If the effective number of bidirectional combined motion information candidates is 1 or more (YES in S291), the subsequent processing is performed to change the candidate number management table. If the unidirectional prediction number is 0 (NO in S291), the process is terminated. The candidate number management table changing unit 154 counts the number of bidirectional combined motion information candidates whose prediction direction is bidirectional, and calculates the effective number of bidirectional combined motion information candidates (S292). The candidate number management table changing unit 154 assigns merge candidate numbers of combined motion information candidates whose prediction direction is unidirectional to the number of bidirectional combined motion information candidates corresponding to the additional number of bidirectional combined motion information candidates (S294).

As a specific example, if the prediction direction of the bidirectional combined motion information candidate (BD0) is bidirectional, the candidate number management table changing unit 154 determines the merge candidate number whose final prediction direction is unidirectional as the bidirectional combined motion. Assigned to information candidate (BD0). In addition, if the direction of motion compensation prediction of the bidirectional combined motion information candidate (BD1) is bidirectional, the candidate number management table changing unit 154 determines a merge candidate number in which the second prediction direction from the last is unidirectional, Assigned to bidirectional combined motion information candidate (BD1). In the third modification of the third embodiment, the calculation of the number of unidirectional predictions is the number of combined motion information candidates whose prediction direction is included in the second combined motion information candidate list. However, the present invention is not limited to this. For example, since the combined motion information with a high selection rate is considered to have high reliability even if the prediction direction is unidirectional, the number of combined motion information candidates in which the prediction direction with a merge candidate number of 3 or more is unidirectional is counted. May be. If the number of invalid combined motion information candidates is 0, the number of combined motion information candidates whose prediction direction is unidirectional is counted. However, the total number of combined motion information candidate invalid numbers and the number of unidirectional predictions is The upper limit is not limited to this as long as a merge candidate number can be assigned to a bidirectional combined motion information candidate.

As described above, the bidirectional combined motion information candidate list generation unit 152 according to Modification 3 replaces the combined motion information candidate whose prediction direction is unidirectional with the bidirectional combined motion information candidate whose prediction direction is bidirectional.

(Effect of Embodiment 3)
As described above, by using an invalid merge index as a merge candidate number of a bidirectional combined motion information candidate, an increase in the code amount of the merge index due to an increase in the merge candidate number is suppressed, and a combined motion information candidate is selected. The rate can be increased and the coding efficiency can be improved.

As described above, when the reliability of the motion information in the time direction and the spatial direction is high, the merge is performed so that the merge candidate number of the bidirectional combined motion information candidate is larger than the merge candidate number of the unidirectional combined motion information candidate. By using the candidate number, the encoding efficiency of the merge index can be improved.

As described above, by associating the combined motion information candidate having a large merge candidate number with the bidirectional combined motion information candidate, the combined motion information candidate of the block with high reliability and high selection rate remains, and the selection rate is low. It is possible to adaptively switch between the combined motion information candidate of the block and the bidirectional combined motion information candidate. Therefore, an increase in the code amount of the merge index due to an increase in merge candidate numbers can be suppressed, and the selection rate of the combined motion information candidates can be increased to improve the encoding efficiency.

As described above, the combined motion information candidate whose prediction direction is unidirectional is replaced with the bidirectional combined motion information candidate whose prediction direction is bidirectional, and the bidirectional prediction motion information whose prediction direction is bidirectional is high. By increasing the number of candidates, it is possible to increase the selection rate of combined motion information candidates and improve the coding efficiency.

[Embodiment 4]
(Priority is given to motion information for unidirectional prediction)
The configuration of the moving picture encoding apparatus according to the fourth embodiment is the same as that of the moving picture encoding apparatus 100 according to the first embodiment except for the function of the reference direction motion information determination unit 161. Hereinafter, the difference between the reference direction motion information determination unit 161 in the fourth embodiment and the first embodiment will be described. The operation of the reference direction motion information determination unit 161 according to Embodiment 4 will be described with reference to FIG.

63 is obtained by adding steps S320 to S323 to the flowchart of FIG. 28, and is characterized by step S321. First, the validity of the reference direction LX is set to “0” (S190). The number of combined motion information candidates (NCands) included in the second combined motion information candidate list is repeated, and the following processing is repeated (S320 to S323). Whether the combined motion information candidate is valid in the LX direction and unidirectional prediction is checked (S321). If the LX direction of the combined motion information candidate is valid and unidirectional prediction (YES in S321), the validity of the reference direction LX is set to “1”, and the motion vector and reference index in the reference direction are set. The processing ends with the motion vector in the LX direction of the combined motion information candidate and the reference index (S322). If the LX direction of the combined motion information candidate is valid and is not unidirectional prediction (NO in S321), the next candidate is examined (S323).

When the LX direction of the combined motion information candidate is valid and there is no motion information candidate for unidirectional prediction, the number of combined motion information candidates (NCands) included in the second combined motion information candidate list is repeated. (S191 to S194). The validity of the combined motion information candidate in the LX direction is checked (S192). If the LX direction of the combined motion information candidate is valid (YES in S192), the validity of the reference direction LX is set to “1”, and the motion vector and reference index in the reference direction are set to the LX direction of the combined motion information candidate. The process ends with the motion vector and the reference index (S193). If the LX direction of the combined motion information candidate is invalid (NO in S192), the next candidate is examined (S194). As described above, the reference direction motion information determination unit 161 according to the fourth embodiment differs from the first embodiment in that priority is given to motion information that is unidirectional in determining the reference direction motion information.

The configuration of the moving picture decoding apparatus according to the fourth embodiment is the same as that of the moving picture decoding apparatus 200 according to the first embodiment except for the function of the reference direction motion information determination unit 161. The combined motion information candidate generation unit 140 of the video decoding device in the fourth embodiment is the same as the combined motion information candidate generation unit 140 of the video encoding device in the fourth embodiment.

(Modification of Embodiment 4)
The fourth embodiment can be modified as follows.

(Modification 1: Unidirectional)
In the above-described fourth embodiment, FIG. 63 is given as an example of the operation of the reference direction motion information determination unit 161. However, motion information that is unidirectional may be given priority in determining motion information, and is not limited thereto. For example, step S191 to step S194 in FIG. 63 may be deleted, and the motion information in the reference direction may be limited to motion information in a single direction.

(Variation 2: unidirectional priority in the reverse direction)
In the above-described fourth embodiment, FIG. 63 is given as an example of the operation of the reference direction motion information determination unit 161. However, motion information that is unidirectional may be given priority in determining motion information, and is not limited thereto. For example, also in the reverse direction motion information determination by the reverse direction motion information determination unit 162, priority may be given to motion information that is unidirectional, similar to the reference direction motion information determination unit 161 of the fourth embodiment. Further, in the determination of the backward direction motion information by the backward direction motion information determination unit 162, the selection is limited to the motion information that is unidirectional similarly to the reference direction motion information determination unit 161 of the first modification of the fourth embodiment. May be.

(Effect of Embodiment 4)
In the fourth embodiment, priority is given to motion information that is unidirectional in the determination of motion information in the reference direction, so that highly reliable motion information can be used as motion information in the reference direction. Encoding efficiency can be improved by increasing the selection rate of candidates.

[Embodiment 5]
(Each direction deletion process)
The configuration of the moving picture encoding apparatus of the fifth embodiment is the same as that of the moving picture encoding apparatus 100 of the first embodiment except for the function of the combined motion information candidate generation unit 140. Hereinafter, the difference between the combined motion information candidate generation unit 140 in Embodiment 5 and Embodiment 1 will be described.

Differences from the first embodiment will be described with reference to FIG. 64 regarding the configuration of the combined motion information candidate generation unit 140 according to the fifth embodiment. In FIG. 64, an L0 direction motion information candidate list generation unit 155 and an L1 direction motion information candidate list generation unit 156 are installed instead of the first combined motion information candidate list reduction unit 151 of FIG.

The function of the combined motion information candidate generation unit 140 according to Embodiment 5 will be described. The L0 direction motion information candidate list generation unit 155, for motion information candidates included in the first combined motion information candidate list, when there are a plurality of combined motion information candidates having motion information with overlapping motion information in the L0 direction. Deletes one combined motion information candidate, generates an L0 direction motion information candidate list, and supplies the L0 direction motion information candidate list to the bidirectional combined motion information candidate list generation unit 152.

The L1 direction motion information candidate list generation unit 156, for motion information candidates included in the first combined motion information candidate list, when there are a plurality of combined motion information candidates having motion information with overlapping motion information in the L1 direction. Deletes one combined motion information candidate, generates an L1 direction motion information candidate list, and supplies the L1 direction motion information candidate list to the bidirectional combined motion information candidate list generation unit 152.

The bidirectional combined motion information candidate list generation unit 152 includes the L0 direction motion information candidate list supplied from the L0 direction motion information candidate list generation unit 155 and the L1 direction motion information supplied from the L1 direction motion information candidate list generation unit 156. A bidirectional combined motion information candidate list is generated from the candidate list.

The configuration of the moving picture decoding apparatus according to the fifth embodiment is the same as that of the moving picture decoding apparatus 200 according to the first embodiment except for the function of the combined motion information candidate generation unit 140. The combined motion information candidate generation unit 140 of the video decoding device in the fifth embodiment is the same as the combined motion information candidate generation unit 140 of the video encoding device in the fifth embodiment.

(Effect of Embodiment 5)
In the fifth embodiment, by reducing the redundancy of motion information in the L0 direction and the L1 direction, the generation of the same bidirectional combined motion information is suppressed, and the effectiveness of the bidirectional combined motion information candidates is increased. Efficiency can be improved.

[Embodiment 6]
(Selective use of bidirectional combined motion information candidates)
The configuration of the moving picture coding apparatus according to the sixth embodiment is the same as that of the moving picture coding apparatus 100 according to the first embodiment except for the function of the reference direction determination unit 160. First, the candidate number management table in the sixth embodiment is shown in FIG. 65, and the maximum number of combined motion information candidates included in the combined motion information candidate list is 6. The difference is that the maximum number of combined motion information candidates included in the combined motion information candidate list is 6, and that only one merge candidate number is assigned to the bidirectional combined motion information candidate. Hereinafter, the difference between the reference direction determination unit 160 in the sixth embodiment and the first embodiment will be described. The operation of the reference direction determination unit 160 according to the sixth embodiment will be described with reference to FIG.

The reference direction determination unit 160 repeats the following processing (S300 to S305) for the number of combined motion information candidates (NCands) included in the second combined motion information candidate list. The validity of the combined motion information candidate in the L0 direction is checked (S301). If the L0 direction of the combined motion information candidate is valid (YES in S301), the reference direction is set to L0 and the process ends (S302). If the L0 direction of the combined motion information candidate is invalid (NO in S301), the validity of the combined motion information candidate in the L1 direction is checked (S303). If the L1 direction of the combined motion information candidate is valid (YES in S303), the reference direction is set to L1 and the process ends (S304). If the L1 direction of the combined motion information candidate is invalid (NO in S303), the next candidate is examined (S305). If the reference direction cannot be set, no bidirectional combined motion information candidate is generated (S306).

The configuration of the moving picture decoding apparatus according to the sixth embodiment is the same as that of the moving picture decoding apparatus 200 according to the first embodiment except for the function of the reference direction determination unit 160. The reference direction determination unit 160 of the moving picture decoding apparatus according to the sixth embodiment is the same as the reference direction determination unit 160 of the moving picture encoding apparatus according to the sixth embodiment.

(Effect of Embodiment 6)
In the sixth embodiment, only one bidirectional combined motion information candidate is determined by determining whether the reference direction is the L0 direction or the L1 direction based on the prediction direction of the combined motion information candidate included in the combined motion information candidate list. When it is effective, it is possible to increase the effectiveness of the bidirectional combined motion information candidate and increase the selectivity of the bidirectional combined motion information candidate to improve the encoding efficiency.

The moving image encoded stream output from the moving image encoding apparatus according to the first to sixth embodiments described above is specified so that it can be decoded according to the encoding method used in the first to sixth embodiments. Data format. A moving picture decoding apparatus corresponding to the moving picture encoding apparatus can decode an encoded stream of this specific data format.

More specifically, a merge index indicating a bidirectional combined motion information candidate and a candidate number management table are encoded in the encoded stream. Also, only the merge index indicating the bidirectional combined motion information candidate is encoded in the encoded stream, and the candidate number management table is shared by the video encoding device and the video decoding device, so that the candidate number management table is included in the encoded stream. It does not have to be encoded.

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 encoding and decoding processes can be realized as a transmission, storage, and reception device using hardware, as well as firmware stored in ROM (Read Only Memory), flash memory, and the like. It can also be realized by software such as a computer. The firmware program and software program can be recorded and provided 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. .

In the first embodiment described above, the operation of generating the time combination motion information candidate list has been described using the flowchart of FIG. In the flowchart, there is a process of calculating a motion vector of a temporally coupled motion information candidate (S164). The temporally combined motion information candidate calculates bidirectional motion information based on the reference image ColRefPic and the motion vector mvCol, which are effective prediction directions in the motion information of the candidate block. When the prediction direction of the candidate block is the unidirectional direction of the L0 direction or the L1 direction, it is selected based on the reference image and the motion vector in the prediction direction. When the prediction direction of the candidate block is bidirectional, the selection is made based on either the reference image in the L0 direction or the L1 direction and the motion vector. When a reference image and a motion vector as a reference for generating bidirectional motion information are selected, a motion vector of a temporally combined motion information candidate is calculated.

Here, a method for calculating the motion vectors mvL0t and mvL1t of the temporally combined motion information candidates from the motion vector ColMv and the reference image ColRefPic used as the basis for bidirectional motion information generation will be described with reference to FIG.

The distance between the images of ColPic and ColRefPic is ColDist, the distance between the reference images ColL0Pic in the L0 direction of the temporally coupled motion information candidate and the image to be processed CurPic is CurL0Dist, and the reference image ColL1Pic in the L1 direction of the temporally coupled motion information candidate is the target of processing. Assuming that the distance between images of the image CurPic is CurL1Dist, a motion vector of the following equation 1 obtained by scaling ColMv with a distance ratio of ColDist, CurL0Dist, and CurL1Dist is set as a motion vector of a temporally combined motion information candidate. The inter-image distance is calculated using POC and has a positive / negative sign.
mvL0t = mvCol × CurrL0Dist / ColDist
mvL1t = mvCol × CurrL1Dist / ColDist (Formula 1)
Note that ColPic, ColRefPic, ColL0Pic, and ColL1Pic in FIG. 67 are examples, and other relationships may be used.

DESCRIPTION OF SYMBOLS 100 moving image encoder, 101 prediction block image acquisition part, 102 subtraction part, 103 prediction error encoding part, 104 code sequence generation part, 105 prediction error decoding part, 106 motion compensation part, 107 addition part, 108 motion vector detection Unit, 109 motion information generation unit, 110 frame memory, 111 motion information memory, 120 difference vector calculation unit, 121 combined motion information determination unit, 122 prediction coding mode determination unit, 130 prediction vector candidate list generation unit, 131 prediction vector determination , 132 subtraction unit, 140 combined motion information candidate generation unit, 141 combined motion information selection unit, 150 unidirectional motion information candidate list generation unit, 151 first combined motion information candidate list reduction unit, 152 bidirectional combined motion information Complementary list generation unit, 153, second combined motion information candidate list reduction unit, 154, candidate number management table change unit, 155, L0 direction motion information candidate list generation unit, 156, L1 direction motion information candidate list generation unit, 160, reference direction determination unit, 161 Reference direction motion information determination unit, 162 Reverse direction motion information determination unit, 163 Bidirectional motion information determination unit, 200 Video decoding device, 201 Code sequence analysis unit, 202 Prediction error decoding unit, 203 Addition unit, 204 Motion information reproduction , 205 motion compensation unit, 206 frame memory, 207 motion information memory, 210 encoding mode determination unit, 211 motion vector playback unit, 212 combined motion information playback unit, 220 prediction vector candidate list generation unit, 221 prediction vector determination unit, 222 adding unit 230 coupled motion information candidate generating unit, 231 coupled motion information selector.

The present invention can be used for a moving picture encoding and decoding technique using motion compensated prediction.

Claims

An image encoding device that performs motion compensation prediction,
A plurality of blocks that have one or two pieces of motion information each including at least motion vector information and reference image information are selected from a plurality of already-encoded blocks adjacent to the encoding target block. A candidate list generating unit that generates a candidate list including motion information candidates used for motion compensation prediction from the motion information of the block;
A first motion information acquisition unit that acquires motion information of a first prediction list from a first candidate included in the candidates;
A second motion information acquisition unit that acquires motion information of a second prediction list from a second candidate included in the candidates;
Combining the motion information of the first prediction list acquired by the first motion information acquisition unit with the motion information of the second prediction list acquired by the second motion information acquisition unit, motion information A selection candidate generator for generating new candidates of
An image encoding device comprising:
The candidate list generation unit generates a candidate list including a new candidate generated by the selection candidate generation unit when the number of candidates is less than a set maximum number.
The image coding apparatus according to claim 1.
The candidate list generation unit generates a candidate list including one or more new candidates generated by the selection candidate generation unit so that the number of candidates does not exceed the maximum number;
The image coding apparatus according to claim 2, wherein:
A code string generation unit that encodes candidate specifying information for specifying motion information candidates used for motion compensation prediction in the candidate list;
The image encoding apparatus according to claim 1, further comprising:
The candidate list generation unit allocates candidate identification information larger than the candidate to a new candidate generated by the selection candidate generation unit,
The image coding apparatus according to claim 4, wherein:
The first prediction list and the second prediction list are different prediction lists;
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
The candidate list generation unit includes motion information derived from motion information of a block of an image temporally different from an image including the encoding target block in the candidate list.
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
The first motion information acquisition unit searches for the candidates according to a first priority order, and sets a valid candidate as the first candidate.
The second motion information acquisition unit searches the candidates according to a second priority order, and sets a valid candidate as the second candidate.
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
The first motion information acquisition unit sets a predetermined candidate among the candidates as the first candidate,
The second motion information acquisition unit sets another predetermined candidate among the candidates as the second candidate.
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
The selection candidate generation unit includes both the motion information of the first prediction list and the motion information of the second prediction list acquired by the first motion information acquisition unit and the second motion information acquisition unit. If is valid, the new candidate is generated.
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
11. The image encoding device according to claim 1, wherein the new candidate has two pieces of motion information.
The new candidate has one piece of motion information,
The image encoding device according to claim 1, wherein the image encoding device is an image encoding device.
An image encoding method for performing motion compensation prediction,
A plurality of blocks that have one or two pieces of motion information each including at least motion vector information and reference image information are selected from a plurality of already-encoded blocks adjacent to the encoding target block. Generating a candidate list including motion information candidates used for motion compensation prediction from the motion information of the block;
Obtaining motion information of a first prediction list from a first candidate included in the candidate list;
Obtaining motion information of a second prediction list from a second candidate included in the candidate list;
Combining the motion information of the first prediction list and the motion information of the second prediction list to generate a new candidate for motion information;
An image encoding method comprising:
An image encoding program for performing motion compensation prediction,
A plurality of blocks that have one or two pieces of motion information each including at least motion vector information and reference image information are selected from a plurality of already-encoded blocks adjacent to the encoding target block. A process for generating a candidate list including motion information candidates used for motion compensation prediction from the motion information of the block;
A process of acquiring motion information of the first prediction list from the first candidate included in the candidate list;
A process of obtaining motion information of a second prediction list from a second candidate included in the candidate list;
A process of generating new candidates for motion information by combining the motion information of the first prediction list and the motion information of the second prediction list;
An image encoding program that causes a computer to execute the above.
An image decoding apparatus that performs motion compensation prediction,
From a plurality of decoded blocks adjacent to the decoding target block, a plurality of blocks each having one or two pieces of motion information including at least motion vector information and reference image information are selected, and the selected block A candidate list generating unit that generates a candidate list including motion information candidates used for motion compensation prediction from the motion information;
A first motion information acquisition unit that acquires motion information of a first prediction list from a first candidate included in the candidates;
A second motion information acquisition unit that acquires motion information of a second prediction list from a second candidate included in the candidates;
Combining the motion information of the first prediction list acquired by the first motion information acquisition unit with the motion information of the second prediction list acquired by the second motion information acquisition unit, motion information A selection candidate generator for generating new candidates of
An image decoding apparatus comprising:
The candidate list generation unit generates a candidate list including a new candidate generated by the selection candidate generation unit when the number of candidates is less than a set maximum number.
The image decoding apparatus according to claim 15.
The candidate list generation unit generates a candidate list including one or more new candidates generated by the selection candidate generation unit so that the number of candidates does not exceed the maximum number;
The image decoding apparatus according to claim 16.
A code string analyzer that decodes candidate specifying information for specifying motion information candidates used for motion compensation prediction in the candidate list;
A selection unit that selects one candidate from candidates included in the candidate list using the decoded candidate identification information;
The image decoding apparatus according to claim 15, further comprising:
The candidate list generation unit allocates candidate identification information larger than the candidate to a new candidate generated by the selection candidate generation unit,
The image decoding device according to claim 18.
The first prediction list and the second prediction list are different prediction lists;
The image decoding device according to claim 15, wherein the image decoding device is an image decoding device.
The candidate list generation unit includes motion information derived from motion information of a block of an image temporally different from an image including the decoding target block in the candidate list;
The image decoding device according to any one of claims 15 to 20, wherein
The first motion information acquisition unit searches for the candidates according to a first priority order, and sets a valid candidate as the first candidate.
The second motion information acquisition unit searches the candidates according to a second priority order, and sets a valid candidate as the second candidate.
The image decoding device according to any one of claims 15 to 21, wherein
The first motion information acquisition unit sets a predetermined candidate among the candidates as the first candidate,
The second motion information acquisition unit sets another predetermined candidate among the candidates as the second candidate.
The image decoding device according to any one of claims 15 to 21, wherein
The selection candidate generation unit includes both the motion information of the first prediction list and the motion information of the second prediction list acquired by the first motion information acquisition unit and the second motion information acquisition unit. If is valid, the new candidate is generated.
The image decoding device according to any one of claims 15 to 23, wherein:
The image decoding device according to any one of claims 15 to 24, wherein the new candidate has two pieces of motion information.
The new candidate has one piece of motion information,
The image decoding device according to any one of claims 15 to 23, wherein:
An image decoding method for performing motion compensation prediction,
From a plurality of decoded blocks adjacent to the decoding target block, a plurality of blocks each having one or two pieces of motion information including at least motion vector information and reference image information are selected, and the selected block Generating a candidate list including motion information candidates used for motion compensation prediction from the motion information;
Obtaining motion information of a first prediction list from a first candidate included in the candidates;
Obtaining motion information of a second prediction list from a second candidate included in the candidates;
Combining the motion information of the first prediction list and the motion information of the second prediction list to generate a new candidate for motion information;
An image decoding method comprising:
An image decoding program for performing motion compensation prediction,
From a plurality of decoded blocks adjacent to the decoding target block, a plurality of blocks each having one or two pieces of motion information including at least motion vector information and reference image information are selected, and the selected block A process of generating a candidate list including motion information candidates used for motion compensation prediction from motion information;
Processing for obtaining motion information of the first prediction list from the first candidate included in the candidates;
A process of acquiring motion information of the second prediction list from a second candidate included in the candidates;
A process of generating new candidates for motion information by combining the motion information of the first prediction list and the motion information of the second prediction list;
An image decoding program that causes a computer to execute the above.