WO2018193967A1

WO2018193967A1 - Encoding device, decoding device, encoding method and decoding method

Info

Publication number: WO2018193967A1
Application number: PCT/JP2018/015411
Authority: WO
Inventors: 安倍　清史; 西　孝啓; 遠間　正真; 龍一加納; 橋本　隆
Original assignee: パナソニックインテレクチュアルプロパティコーポレーションオブアメリカ
Priority date: 2017-04-19
Filing date: 2018-04-12
Publication date: 2018-10-25

Abstract

This encoding device (100) is provided with memory (162) and a circuit (160) which can access the memory (162). The circuit (160) derives a motion vector of a block of an image in a video, performs motion compensation by block unit or by sub-block unit, wherein sub-blocks configure a block. In the case of deriving a motion vector of a block with a template Frame Rate Up-Conversion (FRUC) method and performing motion compensation by sub-block unit, the motion vectors of the sub-blocks are derived with a bilateral FRUC method, and motion compensation is performed by sub-block unit using motion vectors of the sub-blocks.

Description

Encoding device, decoding device, encoding method, and decoding method

The present disclosure relates to an encoding device that encodes a moving image by performing motion compensation.

Conventionally, as a standard for encoding moving images, H.264 265 exists. H. H.265 is also called HEVC (High Efficiency Video Coding).

However, when motion compensation is performed inefficiently in encoding and decoding of moving images, there is a possibility that the amount of code, image quality, processing speed, etc. will be adversely affected.

Therefore, the present disclosure provides an encoding device and the like that can efficiently perform motion compensation.

An encoding apparatus according to an aspect of the present disclosure is an encoding apparatus that encodes a moving image by performing motion compensation, and includes a memory and a circuit that can access the memory, and the memory is accessible The circuit derives a motion vector of an image block in the moving image, performs the motion compensation in a unit of the block or a unit of a sub-block constituting the block, and a template FRUC (Frame Rate Up-Conversion). ) Method to derive the motion vector of the block and perform the motion compensation in the unit of the sub-block, the motion vector of the sub-block is derived by the bilateral FRUC method, and the motion vector of the sub-block is used. The motion compensation is performed in units of the sub-block, and the template FRUC The equation is a method of deriving the motion vector of the processing target area that is the block or the sub-block according to the matching degree between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture. In addition, the bilateral FRUC method is a method of deriving the motion vector of the processing target region according to the matching degree of two reconstructed images of two regions in two different reference pictures.

Note that these comprehensive or specific aspects may be realized by a system, apparatus, method, integrated circuit, computer program, or non-transitory recording medium such as a computer-readable CD-ROM. The present invention may be realized by any combination of an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

The encoding apparatus and the like according to one aspect of the present disclosure can efficiently perform motion compensation.

FIG. 1 is a block diagram showing a functional configuration of the encoding apparatus according to Embodiment 1. FIG. 2 is a diagram illustrating an example of block division in the first embodiment. FIG. 3 is a table showing conversion basis functions corresponding to each conversion type. FIG. 4A is a diagram illustrating an example of the shape of a filter used in ALF. FIG. 4B is a diagram illustrating another example of the shape of a filter used in ALF. FIG. 4C is a diagram illustrating another example of the shape of a filter used in ALF. FIG. 5A is a diagram illustrating 67 intra prediction modes in intra prediction. FIG. 5B is a flowchart for explaining the outline of the predicted image correction process by the OBMC process. FIG. 5C is a conceptual diagram for explaining the outline of the predicted image correction process by the OBMC process. FIG. 5D is a diagram illustrating an example of FRUC. FIG. 6 is a diagram for explaining pattern matching (bilateral matching) between two blocks along the motion trajectory. FIG. 7 is a diagram for explaining pattern matching (template matching) between a template in the current picture and a block in the reference picture. FIG. 8 is a diagram for explaining a model assuming constant velocity linear motion. FIG. 9A is a diagram for explaining derivation of a motion vector in units of sub-blocks based on motion vectors of a plurality of adjacent blocks. FIG. 9B is a diagram for explaining the outline of the motion vector deriving process in the merge mode. FIG. 9C is a conceptual diagram for explaining an outline of DMVR processing. FIG. 9D is a diagram for describing an overview of a predicted image generation method using luminance correction processing by LIC processing. FIG. 10 is a block diagram showing a functional configuration of the decoding apparatus according to the first embodiment. FIG. 11 is a block diagram for explaining processing related to inter-screen prediction performed by the encoding apparatus according to Embodiment 1. FIG. 12 is a block diagram for explaining processing related to inter-screen prediction performed by the decoding apparatus according to Embodiment 1. FIG. 13 is a flowchart showing a first specific example of inter-screen prediction according to the first embodiment. FIG. 14 is a flowchart showing a second specific example of inter-screen prediction according to the first embodiment. FIG. 15 is a flowchart showing a third specific example of inter-screen prediction according to the first embodiment. FIG. 16 is a flowchart illustrating a fourth specific example of inter-screen prediction according to the first embodiment. FIG. 17 is a flowchart showing a fifth specific example of inter-screen prediction according to the first embodiment. FIG. 18 is a flowchart illustrating a sixth specific example of inter-screen prediction according to the first embodiment. FIG. 19 is a conceptual diagram showing the template FRUC method according to the first embodiment. FIG. 20 is a conceptual diagram showing the bilateral FRUC method according to the first embodiment. FIG. 21 is a flowchart showing an operation of deriving a motion vector by the FRUC method according to the first embodiment. FIG. 22 is a block diagram illustrating an implementation example of the coding apparatus according to Embodiment 1. FIG. 23 is a flowchart showing a first operation example of the coding apparatus according to Embodiment 1. FIG. 24 is a flowchart showing a second operation example of the coding apparatus according to Embodiment 1. FIG. 25 is a block diagram illustrating an implementation example of the decoding apparatus according to the first embodiment. FIG. 26 is a flowchart showing a first operation example of the decoding apparatus according to the first embodiment. FIG. 27 is a flowchart showing a second operation example of the decoding apparatus according to the first embodiment. FIG. 28 is an overall configuration diagram of a content supply system that implements a content distribution service. FIG. 29 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 30 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 31 is a diagram illustrating an example of a web page display screen. FIG. 32 shows an example of a web page display screen. FIG. 33 is a diagram illustrating an example of a smartphone. FIG. 34 is a block diagram illustrating a configuration example of a smartphone.

(Knowledge that became the basis of this disclosure)
Motion compensation may be performed in encoding and decoding of moving images. Motion compensation is also called inter-screen prediction or inter prediction. A motion vector is used for motion compensation. As a method for deriving this motion vector, for example, there are a normal inter-screen prediction method, a FRUC (Frame Rate Up-Conversion) method, and the like.

In the normal inter-screen prediction method, the encoding device derives a motion vector using the image of the processing target area in the processing target picture. The encoding device encodes motion vector information. The decoding device derives a motion vector by decoding the information on the motion vector. Accordingly, the encoding device and the decoding device can perform motion compensation using the same motion vector.

In the FRUC method, the encoding device derives a motion vector using a reconstructed image of a region different from the processing target region without using the processing target region image in the processing target picture. The decoding apparatus also derives a motion vector using a reconstructed image of a region different from the processing target region without using the processing target region image in the processing target picture.

Specifically, there are a template FRUC method and a bilateral FRUC method as FRUC methods. In the template FRUC method, a motion vector is derived using a reconstructed image of a region adjacent to a processing target region and a reconstructed image of a reference region in a reference picture. In the bilateral FRUC method, motion vectors are derived using two reconstructed images of two reference regions in two reference pictures.

Thereby, the encoding device and the decoding device can derive the same motion vector by a common method without encoding and decoding the motion vector, and perform motion compensation using the same motion vector. Can do. Therefore, the code amount is reduced.

Also, in the FRUC method, motion compensation is performed in units smaller than the encoding unit. Specifically, in the normal inter-frame prediction method, motion compensation is performed in units of blocks called encoding units or prediction units. In the FRUC method, motion compensation is performed in units of sub-blocks that are finer than this block unit. Done. In the FRUC method, since the motion vector is not encoded and decoded, the motion compensation is performed in a fine unit, so that the prediction accuracy can be improved without increasing the code amount.

However, motion compensation may not be performed efficiently, which may adversely affect the code amount, image quality, processing speed, or the like.

For example, in the template FRUC method, a reconstructed image of a region adjacent to the processing target region is used to derive a motion vector. Therefore, when the reconstructed image of the area adjacent to the sub-block is not generated, the motion vector of the sub-block is not appropriately derived by the template FRUC method, and the motion compensation is not efficiently performed.

Also, when motion compensation is performed in units of sub-blocks, the amount of processing increases and processing delay may increase. In addition, in motion compensation performed in units of sub-blocks, depending on the content of an image, prediction accuracy may not be improved as compared with motion compensation performed in units of blocks.

Thus, for example, an encoding device according to an aspect of the present disclosure is an encoding device that encodes a moving image by performing motion compensation, and includes a memory and a circuit that can access the memory, and the memory The circuit that can access the image derives the motion vector of the block of the image in the moving image, performs the motion compensation in the unit of the block or the unit of the sub-block constituting the block, and generates a template FRUC (Frame When the motion vector of the block is derived by the rate up-conversion method and the motion compensation is performed in units of the sub-block, the motion vector of the sub-block is derived by the bilateral FRUC method and the motion of the sub-block is derived. Performing the motion compensation in units of the sub-block using a vector, In the rate FRUC method, the motion vector of the processing target area that is the block or the sub-block is derived according to the degree of matching between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture. The bilateral FRUC method is a method for deriving the motion vector of the processing target region according to the degree of matching between two reconstructed images of two regions in two different reference pictures.

Accordingly, the encoding apparatus can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, the encoding apparatus can appropriately derive the motion vector of the sub block even when the reconstructed image of the region adjacent to the sub block is not generated. Then, the encoding apparatus can efficiently perform motion compensation by using the appropriately derived motion vector.

For example, when the circuit derives a motion vector of the block by the template FRUC method and performs the motion compensation in the unit of the block or the unit of the sub-block, the motion vector of the block is unidirectionally predicted. If the motion vector of the block is a motion vector for bi-prediction, the motion compensation of the block is performed using the motion vector. Then, the motion compensation is performed in units of the sub-blocks.

Accordingly, the encoding apparatus can derive the sub-block motion vector by the bilateral FRUC method when the motion vector derived as the block motion vector by the template FRUC method is suitable for the bilateral FRUC method. . Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector derived as the motion vector of the block in the template FRUC method is not suitable for the bilateral FRUC method, the encoding device efficiently performs motion compensation in units of blocks using the block motion vector as it is. It can be carried out.

For example, when the circuit derives the motion vector of the block by the bilateral FRUC method and performs the motion compensation in units of the subblock, the circuit calculates the motion vector of the subblock by the bilateral FRUC method. And the motion compensation is performed in units of the sub-block using the motion vector of the sub-block.

As a result, the encoding apparatus obtains the sub-block motion vector by the bilateral FRUC method regardless of whether the block motion vector is derived by the template FRUC method or the block motion vector by the bilateral FRUC method. Can be derived. Therefore, the encoding apparatus can derive the motion vector of the sub-block in the same way in these two cases.

For example, when the circuit derives the motion vector of the sub-block, the circuit derives a candidate for the motion vector of the sub-block using the motion vector of the block, and uses the derived candidate for the sub-block. The motion vector of is derived.

Thereby, the encoding apparatus can derive the motion vector of the sub-block using the motion vector of the block. Therefore, the encoding device can improve prediction accuracy.

Further, for example, a decoding device according to an aspect of the present disclosure is a decoding device that performs motion compensation and decodes a moving image, and includes a memory and a circuit that can access the memory, and can access the memory The circuit derives a motion vector of an image block in the moving image, performs the motion compensation in the unit of the block or a unit of a sub-block constituting the block, and generates a template FRUC (Frame Rate Up- When the motion vector of the block is derived by the conversion method and the motion compensation is performed in units of the sub block, the motion vector of the sub block is derived by the bilateral FRUC method, and the motion vector of the sub block is used. And performing the motion compensation in units of the sub-block, In the RUC method, a motion vector of a processing target area that is the block or the sub-block is derived according to a matching degree between a reconstructed image of a region adjacent to the processing target region and a reconstructed image of a region in a reference picture. The bilateral FRUC method is a method of deriving the motion vector of the processing target region according to the matching degree of two reconstructed images of two regions in two different reference pictures.

Thus, the decoding apparatus can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, the decoding apparatus can appropriately derive the motion vector of the sub block even when the reconstructed image of the region adjacent to the sub block is not generated. Then, the decoding apparatus can efficiently perform motion compensation using the appropriately derived motion vector.

For example, when the circuit derives a motion vector of the block by the template FRUC method and performs the motion compensation in the unit of the block or the unit of the sub-block, the motion vector of the block is unidirectionally predicted. If the motion vector of the block is a bi-predicted motion vector, the motion compensation of the block is performed using the motion vector of the block. Then, the motion compensation is performed in units of the sub-blocks.

Thereby, the decoding device can derive the sub-block motion vector by the bilateral FRUC method when the motion vector derived as the block motion vector by the template FRUC method is suitable for the bilateral FRUC method. Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when a motion vector derived as a block motion vector in the template FRUC method is not suitable for the bilateral FRUC method, the decoding apparatus efficiently performs motion compensation in units of blocks using the block motion vector as it is. be able to.

As a result, the decoding apparatus derives the sub-block motion vector by the bilateral FRUC method regardless of whether the block motion vector is derived by the template FRUC method or the block motion vector by the bilateral FRUC method. can do. Therefore, the decoding apparatus can derive the motion vector of the sub-block in the same way in these two cases.

Thereby, the decoding apparatus can derive the motion vector of the sub-block using the motion vector of the block. Therefore, the decoding apparatus can improve prediction accuracy.

Further, for example, an encoding method according to an aspect of the present disclosure is an encoding method for encoding a moving image by performing motion compensation, in which a motion vector of an image block in the moving image is derived, and the block Or the sub-block unit constituting the block, the motion compensation is performed, and the motion vector of the block is derived by a template FRUC (Frame Rate Up-Conversion) method, and the motion is performed in the sub-block unit. When performing compensation, a motion vector of the sub-block is derived by a bilateral FRUC method, the motion compensation is performed in units of the sub-block using the motion vector of the sub-block, and the template FRUC method Alternatively, the motion vector of the processing target area that is the sub-block is The bilateral FRUC method is a method of deriving according to the degree of matching between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture. This is a method of deriving according to the degree of matching between two reconstructed images of two regions in two different reference pictures.

Thus, an apparatus using this encoding method can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, a device or the like using this encoding method can appropriately derive a motion vector of a sub block even when a reconstructed image of an area adjacent to the sub block is not generated. An apparatus using this encoding method can efficiently perform motion compensation using an appropriately derived motion vector.

Further, for example, a decoding method according to an aspect of the present disclosure is a decoding method that performs motion compensation and decodes a moving image, and derives a motion vector of an image block in the moving image, the unit of the block, Alternatively, the motion compensation is performed in units of subblocks constituting the block, and the motion vector of the block is derived by a template FRUC (Frame Rate Up-Conversion) method, and the motion compensation is performed in units of the subblocks. In this case, a motion vector of the sub-block is derived by a bilateral FRUC scheme, the motion compensation is performed in units of the sub-block using the motion vector of the sub-block, and the template FRUC scheme is configured to use the block or the sub-block. The motion vector of the processing target area which is a block is This is a method of deriving according to the degree of matching between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture, and the bilateral FRUC method uses different motion vectors for the processing target region. This is a method of deriving according to the degree of matching between two reconstructed images of two regions in two reference pictures.

Thus, an apparatus or the like using this decoding method can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, a device or the like using this decoding method can appropriately derive a motion vector of a sub block even when a reconstructed image of an area adjacent to the sub block is not generated. An apparatus using this decoding method can efficiently perform motion compensation using an appropriately derived motion vector.

Further, for example, an encoding device according to an aspect of the present disclosure is an encoding device that performs motion compensation and encodes a moving image, and includes a memory and a circuit that can access the memory, and the memory The circuit accessible to encodes first control information indicating one method for deriving a motion vector of an image block in the moving image, and performs the motion compensation in units of sub-blocks constituting the block Is it effective to encode the second control information indicating whether is effective or invalid, derive the motion vector of the block by the one method, and perform the motion compensation in units of the sub-blocks? It is determined whether the motion compensation is performed in units of the sub-blocks or the motion compensation is performed in units of the blocks according to whether it is invalid. When it is determined that compensation is to be performed, a motion vector of the sub-block is derived, the motion compensation is performed in units of the sub-block using the motion vector of the sub-block, and the motion compensation is performed in units of the block If it is determined, the motion compensation is performed in units of the block using the motion vector of the block.

Accordingly, the encoding apparatus can enable or disable the motion compensation in units of sub-blocks separately from the method of deriving the block motion vector. Therefore, the encoding apparatus can appropriately suppress that the motion compensation is performed inefficiently. That is, the encoding device can efficiently perform motion compensation.

For example, the circuit selects the one method from a plurality of methods including a normal inter-screen prediction method, a template FRUC (Frame Rate Up-Conversion) method, and a bilateral FRUC method, and the normal inter-screen prediction method. Is a method of deriving a motion vector of the processing target region that is the block or the sub-block, and encoding information on the motion vector of the processing target region, and the template FRUC method is a motion vector of the processing target region. Is derived in accordance with the degree of matching between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture, and the bilateral FRUC method calculates the motion vector of the processing target region. , Two of the two regions in two different reference pictures It is a method to derive in accordance goodness of the reconstructed image.

Thereby, the encoding apparatus can adaptively select one method for deriving the motion vector of the block from a plurality of methods.

Further, for example, in the case where the one method is a template FRUC method or a bilateral FRUC method, (i) when it is determined that the motion compensation is performed in units of the subblock, The motion compensation is performed in units, and (ii) the motion compensation is performed in units of blocks when it is determined that the motion compensation is performed in units of blocks, and the template FRUC scheme is the block or subblock Is a method for deriving a motion vector of a processing target region according to the degree of matching between a reconstructed image of a region adjacent to the processing target region and a reconstructed image of a region in a reference picture, and the bilateral FRUC method is The motion vector of the processing target region is set to two regions in two different reference pictures. It is a method to derive in accordance with goodness of two reconstructed images.

Accordingly, the encoding device can perform motion compensation in an appropriate unit according to a determination result of whether or not to perform motion compensation in units of sub-blocks when a block motion vector is derived by the FRUC method. . The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks. Therefore, the encoding apparatus can perform motion compensation in an appropriate unit according to whether or not it is effective to perform motion compensation in units of sub-blocks when a motion vector of a block is derived by the FRUC method. it can.

In addition, for example, in the case where the one method is a normal inter-screen prediction method, the circuit (i) when the motion compensation is determined to be performed in units of the subblocks, the unit in the units of the subblocks. (Ii) When it is determined that the motion compensation is performed in units of the block, the motion compensation is performed in units of the block, and the normal inter-screen prediction method is performed in the block or the sub-block. In this method, a motion vector of a certain processing target area is derived and information on the motion vector of the processing target area is encoded.

As a result, when the motion vector of a block is derived by a normal inter-frame prediction method different from the FRUC method, the encoding device can select an appropriate unit according to a determination result on whether to perform motion compensation in units of subblocks. Motion compensation can be performed. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks.

Therefore, when the motion vector of a block is derived by the normal inter-frame prediction method, the encoding device performs motion compensation in an appropriate unit according to whether it is effective to perform motion compensation in a sub-block unit. It can be carried out.

Also, for example, when the circuit derives the motion vector of the sub-block, the circuit derives the motion vector of the sub-block by the bilateral FRUC method, and the bilateral FRUC method is a process that is the block or the sub-block. In this method, the motion vector of the target region is derived according to the degree of matching between two reconstructed images in two regions in two different reference pictures.

Thereby, the encoding apparatus can appropriately derive the motion vector of the sub-block even when the reconstructed image of the region adjacent to the sub-block is not generated. Therefore, the encoding apparatus can efficiently perform motion compensation by using the appropriately derived motion vector.

In addition, for example, when the motion vector of the block is a motion vector of bidirectional prediction and it is effective to perform the motion compensation in the unit of the sub-block, the circuit compensates for the motion compensation in the unit of the sub-block. If the motion vector of the block is a bi-directional motion vector and it is invalid to perform the motion compensation in units of the sub-blocks, the motion compensation is performed in units of the block. If the motion vector of the block is a unidirectional motion vector, it is determined that the motion compensation is performed in units of the block.

As a result, the encoding apparatus converts the sub-block motion vector to the bilateral FRUC when the motion vector of the block is suitable for the bilateral FRUC scheme and it is effective to perform motion compensation in units of sub-blocks. Can be derived in a manner. Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector of a block is not suitable for the bilateral FRUC method or when it is invalid to perform motion compensation in units of sub-blocks, the encoding device efficiently uses the motion vector of the block as it is. Motion compensation can be performed in units of blocks.

Further, for example, when it is effective to perform the motion compensation in units of the sub-blocks, the circuit determines that the motion compensation is performed in units of the sub-blocks, and the motion compensation is performed in units of the sub-blocks. If it is invalid to perform the motion compensation, it is determined that the motion compensation is performed in units of the block.

Thereby, the encoding apparatus can perform motion compensation in units of sub-blocks when it is effective to perform motion compensation in units of sub-blocks. Then, when it is invalid to perform motion compensation in units of sub-blocks, the encoding device can perform motion compensation in units of blocks. Therefore, the encoding apparatus can simply control the unit in which motion compensation is performed.

For example, the circuit encodes the first control information to a header layer of the block, a header layer of a slice including the block, a header layer of a picture including the block, or a header layer of a stream including the block. The second control information is encoded into the header layer of the block, the header layer of the slice, the header layer of the picture, or the header layer of the stream.

Thereby, the encoding apparatus can designate a scheme for deriving a motion vector of a block and whether or not it is effective to perform motion compensation in units of sub-blocks within an appropriate range.

Further, for example, a decoding device according to an aspect of the present disclosure is a decoding device that performs motion compensation and decodes a moving image, and includes a memory and a circuit that can access the memory, and can access the memory It is effective that the circuit decodes first control information indicating one method for deriving a motion vector of an image block in the moving image, and performs the motion compensation in units of sub-blocks constituting the block. It is effective or ineffective to decode the second control information indicating whether it is present or invalid, derive the motion vector of the block by the one method, and perform the motion compensation in units of the sub-blocks Accordingly, it is determined whether the motion compensation is performed in units of the sub-blocks or the motion compensation is performed in units of the blocks, and the motion compensation is performed in units of the sub-blocks. Is determined, the motion vector of the sub-block is derived, the motion compensation of the sub-block is performed using the motion vector of the sub-block, and the motion compensation is determined to be performed in the unit of the block. In this case, the motion compensation is performed in units of the block using the motion vector of the block.

Thereby, the decoding apparatus can enable or disable the motion compensation in units of sub-blocks separately from the method of deriving the motion vector of the block. Therefore, the decoding apparatus can appropriately suppress inefficient motion compensation. That is, the decoding device can efficiently perform motion compensation.

For example, the circuit selects the one method from a plurality of methods including a normal inter-screen prediction method, a template FRUC (Frame Rate Up-Conversion) method, and a bilateral FRUC method, and the normal inter-screen prediction method. Is a method of decoding motion vector information of the processing target region that is the block or the sub-block and deriving a motion vector of the processing target region, and the template FRUC method uses the motion vector of the processing target region. , A method of deriving according to the degree of matching between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture, and the bilateral FRUC method is a motion vector of the processing target region, Two of the two regions in two different reference pictures It is a method to derive in accordance with goodness of constituent images.

Thereby, the decoding apparatus can adaptively select one method for deriving the motion vector of the block from a plurality of methods.

Thereby, when the motion vector of the block is derived by the FRUC method, the decoding apparatus can perform motion compensation in an appropriate unit according to the determination result of whether or not motion compensation is performed in units of sub-blocks. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks. Therefore, the decoding device can perform motion compensation in an appropriate unit according to whether or not it is effective to perform motion compensation in units of sub-blocks when a motion vector of a block is derived by the FRUC method. .

In addition, for example, in the case where the one method is a normal inter-screen prediction method, the circuit (i) when the motion compensation is determined to be performed in units of the subblocks, the unit in the units of the subblocks. (Ii) When it is determined that the motion compensation is performed in units of the block, the motion compensation is performed in units of the block, and the normal inter-screen prediction method is performed in the block or the sub-block. This is a method of decoding motion vector information of a certain processing target region and deriving the motion vector of the processing target region.

As a result, when the motion vector of the block is derived by the normal inter-frame prediction scheme different from the FRUC scheme, the decoding apparatus performs the appropriate unit according to the determination result of whether or not to perform the motion compensation in the sub-block unit. Motion compensation can be performed. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks.

Therefore, when a motion vector of a block is derived by the normal inter-frame prediction method, the decoding apparatus performs motion compensation in an appropriate unit according to whether it is effective to perform motion compensation in a sub-block unit. be able to.

Thereby, the decoding apparatus can appropriately derive the motion vector of the sub-block even when the reconstructed image of the area adjacent to the sub-block is not generated. Therefore, the decoding apparatus can efficiently perform motion compensation using the appropriately derived motion vector.

As a result, the decoding apparatus converts the sub-block motion vector into the bilateral FRUC scheme when the motion vector of the block is suitable for the bilateral FRUC scheme and it is effective to perform motion compensation in units of sub-blocks. Can be derived. Therefore, for example, when a motion vector of a sub-block is derived using a motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector of the block is not suitable for the bilateral FRUC method, or when it is invalid to perform motion compensation in units of sub-blocks, the decoding apparatus efficiently uses the block motion vector as it is. Motion compensation can be performed in units of.

Thereby, the decoding apparatus can perform motion compensation in units of sub-blocks when it is effective to perform motion compensation in units of sub-blocks. The decoding apparatus can perform motion compensation in units of blocks when it is invalid to perform motion compensation in units of sub-blocks. Therefore, the decoding apparatus can simply control the unit in which motion compensation is performed.

Also, for example, the circuit decodes the first control information from a header layer of the block, a header layer of a slice including the block, a header layer of a picture including the block, or a header layer of a stream including the block. Then, the second control information is decoded from the header layer of the block, the header layer of the slice, the header layer of the picture, or the header layer of the stream.

Thereby, the decoding apparatus can specify a method for deriving a motion vector of a block and whether or not it is effective to perform motion compensation in units of sub-blocks within an appropriate range.

In addition, for example, an encoding method according to an aspect of the present disclosure is an encoding method for encoding a moving image by performing motion compensation, and one method for deriving a motion vector of an image block in the moving image The second control information indicating whether it is effective or invalid to perform the motion compensation in units of sub-blocks constituting the block is encoded, and the one method is used. Deriving a motion vector of the block and performing the motion compensation in units of the sub-blocks according to whether the motion compensation is valid or invalid in units of the sub-blocks or in units of the blocks It is determined whether to perform motion compensation, and when it is determined to perform the motion compensation in units of the sub-block, a motion vector of the sub-block is derived, If it is determined that the motion compensation is performed in units of the sub-block using a vector and the motion compensation is performed in units of the block, the motion compensation is performed in units of the block using the motion vector of the block. Do.

Thus, an apparatus or the like using this encoding method can validate or invalidate motion compensation in units of sub-blocks separately from a method for deriving a block motion vector. Therefore, an apparatus using this encoding method can appropriately suppress inefficient motion compensation. That is, a device using this encoding method can efficiently perform motion compensation.

In addition, for example, a decoding method according to an aspect of the present disclosure is a decoding method that decodes a moving image by performing motion compensation, and is a first method that derives a motion vector of an image block in the moving image. 1 control information is decoded, second control information indicating whether it is effective or ineffective to perform the motion compensation in units of sub-blocks constituting the block is decoded, and the block Deriving a motion vector and performing the motion compensation in units of the sub-blocks according to whether it is valid or invalid to perform the motion compensation in units of the sub-blocks or performing the motion compensation in units of the blocks If it is determined that the motion compensation is performed in units of the sub-block, a motion vector of the sub-block is derived and a motion vector of the sub-block is derived. Performs the motion compensation in units of the sub-block using, if it is determined to perform the motion compensation in units of the blocks, it carries out the motion compensation in units of the block using the motion vector of the block.

Accordingly, an apparatus using this decoding method can validate or invalidate motion compensation in units of sub-blocks separately from a method for deriving a block motion vector. Therefore, an apparatus using this decoding method can appropriately suppress inefficient motion compensation. That is, an apparatus using this decoding method can efficiently perform motion compensation.

Furthermore, these comprehensive or specific aspects may be realized by a system, an apparatus, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM. The present invention may be realized by any combination of an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

Hereinafter, embodiments will be specifically described with reference to the drawings.

It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the scope of the claims. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

(Embodiment 1)
First, an outline of the first embodiment will be described as an example of an encoding device and a decoding device to which the processing and / or configuration described in each aspect of the present disclosure to be described later can be applied. However, the first embodiment is merely an example of an encoding device and a decoding device to which the processing and / or configuration described in each aspect of the present disclosure can be applied, and the processing and / or processing described in each aspect of the present disclosure. The configuration can also be implemented in an encoding device and a decoding device different from those in the first embodiment.

When applying the processing and / or configuration described in each aspect of the present disclosure to Embodiment 1, for example, one of the following may be performed.

(1) The encoding apparatus or decoding apparatus according to the first embodiment corresponds to the constituent elements described in each aspect of the present disclosure among a plurality of constituent elements constituting the encoding apparatus or decoding apparatus. Replacing components with components described in each aspect of the disclosure

(2) Addition of a function or processing to be performed on some of the constituent elements of the encoding apparatus or decoding apparatus to the encoding apparatus or decoding apparatus of the first embodiment, After making any changes such as replacement and deletion, the components corresponding to the components described in each aspect of the present disclosure are replaced with the components described in each aspect of the present disclosure.

(3) Addition of processes to the method performed by the encoding apparatus or decoding apparatus of the first embodiment and / or replacement or deletion of some processes among a plurality of processes included in the method With any change in the above, the processing corresponding to the processing described in each aspect of the present disclosure is replaced with the processing described in each aspect of the present disclosure.

(4) A part of the components constituting the encoding device or the decoding device according to the first embodiment is described in each aspect of the present disclosure, and in each aspect of the present disclosure. To be implemented in combination with a component that includes a part of the function provided by the component to be performed, or a component that performs a part of processing performed by the component described in each aspect of the present disclosure

(5) A component provided with a part of the functions of some of the components constituting the encoding device or the decoding device of the first embodiment, or the encoding device of the first embodiment Alternatively, the constituent elements that perform part of the processing performed by some constituent elements of the plurality of constituent elements constituting the decoding device are the constituent elements described in each aspect of the present disclosure, and the respective aspects of the present disclosure. To be implemented in combination with a component that includes a part of the function of the component to be described, or a component that performs a part of processing performed by the component described in each aspect of the present disclosure

(6) For the method performed by the encoding device or the decoding device according to Embodiment 1, processing corresponding to the processing described in each aspect of the present disclosure among the plurality of processing included in the method is Replace with the process described in each aspect of the disclosure

(7) A part of the plurality of processes included in the method performed by the encoding apparatus or the decoding apparatus according to the first embodiment is combined with the processes described in each aspect of the present disclosure.

Note that the processes and / or configurations described in each aspect of the present disclosure are not limited to the above examples. For example, the present invention may be implemented in an apparatus used for a different purpose from the moving picture / picture encoding apparatus or moving picture / picture decoding apparatus disclosed in the first embodiment, and the processing and / or described in each aspect. The configuration may be implemented alone. Moreover, you may implement combining the process and / or structure which were demonstrated in the different aspect.

[Outline of encoding device]
First, the outline | summary of the encoding apparatus which concerns on Embodiment 1 is demonstrated. FIG. 1 is a block diagram showing a functional configuration of encoding apparatus 100 according to Embodiment 1. The encoding device 100 is a moving image / image encoding device that encodes moving images / images in units of blocks.

As shown in FIG. 1, an encoding apparatus 100 is an apparatus that encodes an image in units of blocks, and includes a dividing unit 102, a subtracting unit 104, a transforming unit 106, a quantizing unit 108, and entropy encoding. Unit 110, inverse quantization unit 112, inverse transform unit 114, addition unit 116, block memory 118, loop filter unit 120, frame memory 122, intra prediction unit 124, inter prediction unit 126, A prediction control unit 128.

The encoding device 100 is realized by, for example, a general-purpose processor and a memory. In this case, when the software program stored in the memory is executed by the processor, the processor performs the division unit 102, the subtraction unit 104, the conversion unit 106, the quantization unit 108, the entropy encoding unit 110, and the inverse quantization unit 112. , An inverse transform unit 114, an addition unit 116, a loop filter unit 120, an intra prediction unit 124, an inter prediction unit 126, and a prediction control unit 128. The encoding apparatus 100 includes a dividing unit 102, a subtracting unit 104, a transforming unit 106, a quantizing unit 108, an entropy coding unit 110, an inverse quantizing unit 112, an inverse transforming unit 114, an adding unit 116, and a loop filter unit 120. The intra prediction unit 124, the inter prediction unit 126, and the prediction control unit 128 may be implemented as one or more dedicated electronic circuits.

Hereinafter, each component included in the encoding device 100 will be described.

[Division part]
The dividing unit 102 divides each picture included in the input moving image into a plurality of blocks, and outputs each block to the subtracting unit 104. For example, the dividing unit 102 first divides a picture into blocks of a fixed size (for example, 128 × 128). This fixed size block may be referred to as a coding tree unit (CTU). Then, the dividing unit 102 divides each of the fixed size blocks into blocks of a variable size (for example, 64 × 64 or less) based on recursive quadtree and / or binary tree block division. . This variable size block may be referred to as a coding unit (CU), a prediction unit (PU) or a transform unit (TU). In the present embodiment, CU, PU, and TU do not need to be distinguished, and some or all blocks in a picture may be processing units of CU, PU, and TU.

FIG. 2 is a diagram showing an example of block division in the first embodiment. In FIG. 2, a solid line represents a block boundary by quadtree block division, and a broken line represents a block boundary by binary tree block division.

Here, the block 10 is a 128 × 128 pixel square block (128 × 128 block). The 128 × 128 block 10 is first divided into four square 64 × 64 blocks (quadtree block division).

The upper left 64 × 64 block is further divided vertically into two rectangular 32 × 64 blocks, and the left 32 × 64 block is further divided vertically into two rectangular 16 × 64 blocks (binary tree block division). As a result, the upper left 64 × 64 block is divided into two 16 × 64 blocks 11 and 12 and a 32 × 64 block 13.

The upper right 64 × 64 block is horizontally divided into two rectangular 64 × 32 blocks 14 and 15 (binary tree block division).

The lower left 64x64 block is divided into four square 32x32 blocks (quadrant block division). Of the four 32 × 32 blocks, the upper left block and the lower right block are further divided. The upper left 32 × 32 block is vertically divided into two rectangular 16 × 32 blocks, and the right 16 × 32 block is further divided horizontally into two 16 × 16 blocks (binary tree block division). The lower right 32 × 32 block is horizontally divided into two 32 × 16 blocks (binary tree block division). As a result, the lower left 64 × 64 block is divided into a 16 × 32 block 16, two 16 × 16

blocks

17 and 18, two 32 × 32

blocks

19 and 20, and two 32 × 16

blocks

21 and 22.

The lower right 64x64 block 23 is not divided.

As described above, in FIG. 2, the block 10 is divided into 13 variable-size blocks 11 to 23 based on the recursive quadtree and binary tree block division. Such division may be called QTBT (quad-tree plus binary tree) division.

In FIG. 2, one block is divided into four or two blocks (quadrature tree or binary tree block division), but the division is not limited to this. For example, one block may be divided into three blocks (triple tree block division). Such a division including a tri-tree block division may be called an MBT (multi type tree) division.

[Subtraction section]
The subtraction unit 104 subtracts the prediction signal (prediction sample) from the original signal (original sample) in units of blocks divided by the division unit 102. That is, the subtraction unit 104 calculates a prediction error (also referred to as a residual) of a coding target block (hereinafter referred to as a current block). Then, the subtraction unit 104 outputs the calculated prediction error to the conversion unit 106.

The original signal is an input signal of the encoding device 100, and is a signal (for example, a luminance (luma) signal and two color difference (chroma) signals) representing an image of each picture constituting the moving image. Hereinafter, a signal representing an image may be referred to as a sample.

[Conversion section]
The transform unit 106 transforms the prediction error in the spatial domain into a transform factor in the frequency domain, and outputs the transform coefficient to the quantization unit 108. Specifically, the transform unit 106 performs, for example, a predetermined discrete cosine transform (DCT) or discrete sine transform (DST) on a prediction error in the spatial domain.

Note that the conversion unit 106 adaptively selects a conversion type from a plurality of conversion types, and converts a prediction error into a conversion coefficient using a conversion basis function corresponding to the selected conversion type. May be. Such a conversion may be referred to as EMT (explicit multiple core transform) or AMT (adaptive multiple transform).

The plurality of conversion types include, for example, DCT-II, DCT-V, DCT-VIII, DST-I and DST-VII. FIG. 3 is a table showing conversion basis functions corresponding to each conversion type. In FIG. 3, N indicates the number of input pixels. Selection of a conversion type from among these multiple conversion types may depend on, for example, the type of prediction (intra prediction and inter prediction), or may depend on an intra prediction mode.

Information indicating whether or not to apply such EMT or AMT (for example, called an AMT flag) and information indicating the selected conversion type are signaled at the CU level. Note that the signalization of these pieces of information need not be limited to the CU level, but may be other levels (for example, a sequence level, a picture level, a slice level, a tile level, or a CTU level).

Further, the conversion unit 106 may reconvert the conversion coefficient (conversion result). Such reconversion is sometimes referred to as AST (adaptive secondary transform) or NSST (non-separable secondary transform). For example, the conversion unit 106 performs re-conversion for each sub-block (for example, 4 × 4 sub-block) included in the block of the conversion coefficient corresponding to the intra prediction error. Information indicating whether or not NSST is applied and information related to the transformation matrix used for NSST are signaled at the CU level. Note that the signalization of these pieces of information need not be limited to the CU level, but may be other levels (for example, a sequence level, a picture level, a slice level, a tile level, or a CTU level).

Here, the separable conversion is a method of performing the conversion a plurality of times by separating the number of dimensions of the input for each direction, and the non-separable conversion is two or more when the input is multidimensional. In this method, the dimensions are collectively regarded as one dimension, and conversion is performed collectively.

For example, as an example of non-separable conversion, if an input is a 4 × 4 block, it is regarded as one array having 16 elements, and 16 × 16 conversion is performed on the array. The thing which performs the conversion process with a matrix is mentioned.

Similarly, a 4 × 4 input block is regarded as a single array having 16 elements, and then the Givens rotation is performed multiple times on the array (Hypercube Givens Transform) is also a non-separable. It is an example of conversion.

[Quantization unit]
The quantization unit 108 quantizes the transform coefficient output from the transform unit 106. Specifically, the quantization unit 108 scans the transform coefficients of the current block in a predetermined scanning order, and quantizes the transform coefficients based on the quantization parameter (QP) corresponding to the scanned transform coefficients. Then, the quantization unit 108 outputs the quantized transform coefficient (hereinafter referred to as a quantization coefficient) of the current block to the entropy encoding unit 110 and the inverse quantization unit 112.

The predetermined order is an order for quantization / inverse quantization of transform coefficients. For example, the predetermined scanning order is defined in ascending order of frequency (order from low frequency to high frequency) or descending order (order from high frequency to low frequency).

The quantization parameter is a parameter that defines a quantization step (quantization width). For example, if the value of the quantization parameter increases, the quantization step also increases. That is, if the value of the quantization parameter increases, the quantization error increases.

[Entropy encoding unit]
The entropy encoding unit 110 generates an encoded signal (encoded bit stream) by performing variable length encoding on the quantization coefficient that is input from the quantization unit 108. Specifically, the entropy encoding unit 110 binarizes the quantization coefficient, for example, and arithmetically encodes the binary signal.

[Inverse quantization unit]
The inverse quantization unit 112 inversely quantizes the quantization coefficient that is an input from the quantization unit 108. Specifically, the inverse quantization unit 112 inversely quantizes the quantization coefficient of the current block in a predetermined scanning order. Then, the inverse quantization unit 112 outputs the inverse-quantized transform coefficient of the current block to the inverse transform unit 114.

[Inverse conversion part]
The inverse transform unit 114 restores the prediction error by inverse transforming the transform coefficient that is an input from the inverse quantization unit 112. Specifically, the inverse transform unit 114 restores the prediction error of the current block by performing an inverse transform corresponding to the transform by the transform unit 106 on the transform coefficient. Then, the inverse transformation unit 114 outputs the restored prediction error to the addition unit 116.

Note that the restored prediction error does not match the prediction error calculated by the subtraction unit 104 because information is lost due to quantization. That is, the restored prediction error includes a quantization error.

[Addition part]
The adder 116 reconstructs the current block by adding the prediction error input from the inverse transform unit 114 and the prediction sample input from the prediction control unit 128. Then, the adding unit 116 outputs the reconfigured block to the block memory 118 and the loop filter unit 120. The reconstructed block is sometimes referred to as a local decoding block.

[Block memory]
The block memory 118 is a storage unit for storing blocks in an encoding target picture (hereinafter referred to as current picture) that are referred to in intra prediction. Specifically, the block memory 118 stores the reconstructed block output from the adding unit 116.

[Loop filter section]
The loop filter unit 120 applies a loop filter to the block reconstructed by the adding unit 116 and outputs the filtered reconstructed block to the frame memory 122. The loop filter is a filter (in-loop filter) used in the encoding loop, and includes, for example, a deblocking filter (DF), a sample adaptive offset (SAO), an adaptive loop filter (ALF), and the like.

In ALF, a least square error filter is applied to remove coding distortion. For example, for each 2 × 2 sub-block in the current block, a plurality of multiples based on the direction of the local gradient and the activity are provided. One filter selected from the filters is applied.

Specifically, first, sub-blocks (for example, 2 × 2 sub-blocks) are classified into a plurality of classes (for example, 15 or 25 classes). Sub-block classification is performed based on gradient direction and activity. For example, the classification value C (for example, C = 5D + A) is calculated using the gradient direction value D (for example, 0 to 2 or 0 to 4) and the gradient activity value A (for example, 0 to 4). Then, based on the classification value C, the sub-blocks are classified into a plurality of classes (for example, 15 or 25 classes).

The direction value D of the gradient is derived, for example, by comparing gradients in a plurality of directions (for example, horizontal, vertical, and two diagonal directions). The gradient activation value A is derived, for example, by adding gradients in a plurality of directions and quantizing the addition result.

-Based on the result of such classification, a filter for a sub-block is determined from among a plurality of filters.

As the shape of the filter used in ALF, for example, a circularly symmetric shape is used. 4A to 4C are diagrams showing a plurality of examples of filter shapes used in ALF. 4A shows a 5 × 5 diamond shape filter, FIG. 4B shows a 7 × 7 diamond shape filter, and FIG. 4C shows a 9 × 9 diamond shape filter. Information indicating the shape of the filter is signalized at the picture level. It should be noted that the signalization of the information indicating the filter shape need not be limited to the picture level, but may be another level (for example, a sequence level, a slice level, a tile level, a CTU level, or a CU level).

ON / OFF of ALF is determined at the picture level or the CU level, for example. For example, for luminance, it is determined whether to apply ALF at the CU level, and for color difference, it is determined whether to apply ALF at the picture level. Information indicating ALF on / off is signaled at the picture level or the CU level. Signaling of information indicating ALF on / off need not be limited to the picture level or the CU level, and may be performed at other levels (for example, a sequence level, a slice level, a tile level, or a CTU level). Good.

A coefficient set of a plurality of selectable filters (for example, up to 15 or 25 filters) is signalized at the picture level. The signalization of the coefficient set need not be limited to the picture level, but may be another level (for example, sequence level, slice level, tile level, CTU level, CU level, or sub-block level).

[Frame memory]
The frame memory 122 is a storage unit for storing a reference picture used for inter prediction, and is sometimes called a frame buffer. Specifically, the frame memory 122 stores the reconstructed block filtered by the loop filter unit 120.

[Intra prediction section]
The intra prediction unit 124 generates a prediction signal (intra prediction signal) by referring to the block in the current picture stored in the block memory 118 and performing intra prediction (also referred to as intra-screen prediction) of the current block. Specifically, the intra prediction unit 124 generates an intra prediction signal by performing intra prediction with reference to a sample (for example, luminance value and color difference value) of a block adjacent to the current block, and performs prediction control on the intra prediction signal. To the unit 128.

For example, the intra prediction unit 124 performs intra prediction using one of a plurality of predefined intra prediction modes. The plurality of intra prediction modes include one or more non-directional prediction modes and a plurality of directional prediction modes.

One or more non-directional prediction modes are for example H.264. It includes Planar prediction mode and DC prediction mode defined by H.265 / HEVC (High-Efficiency Video Coding) standard (Non-patent Document 1).

The multiple directionality prediction modes are for example H.264. It includes 33-direction prediction modes defined in the H.265 / HEVC standard. In addition to the 33 directions, the plurality of directionality prediction modes may further include 32 direction prediction modes (a total of 65 directionality prediction modes). FIG. 5A is a diagram illustrating 67 intra prediction modes (two non-directional prediction modes and 65 directional prediction modes) in intra prediction. The solid line arrows The 33 directions defined in the H.265 / HEVC standard are represented, and the dashed arrow represents the added 32 directions.

Note that the luminance block may be referred to in the intra prediction of the color difference block. That is, the color difference component of the current block may be predicted based on the luminance component of the current block. Such intra prediction is sometimes called CCLM (cross-component linear model) prediction. The intra prediction mode (for example, called CCLM mode) of the color difference block which refers to such a luminance block may be added as one of the intra prediction modes of the color difference block.

The intra prediction unit 124 may correct the pixel value after intra prediction based on the gradient of the reference pixel in the horizontal / vertical direction. Intra prediction with such correction may be called PDPC (position dependent intra prediction combination). Information indicating whether or not PDPC is applied (for example, referred to as a PDPC flag) is signaled, for example, at the CU level. The signalization of this information need not be limited to the CU level, but may be another level (for example, a sequence level, a picture level, a slice level, a tile level, or a CTU level).

[Inter prediction section]
The inter prediction unit 126 refers to a reference picture stored in the frame memory 122 and is different from the current picture, and performs inter prediction (also referred to as inter-screen prediction) of the current block, thereby generating a prediction signal (inter prediction signal). Prediction signal). Inter prediction is performed in units of a current block or a sub-block (for example, 4 × 4 block) in the current block. For example, the inter prediction unit 126 performs motion estimation in the reference picture for the current block or sub-block. Then, the inter prediction unit 126 generates an inter prediction signal of the current block or sub-block by performing motion compensation using motion information (for example, a motion vector) obtained by motion search. Then, the inter prediction unit 126 outputs the generated inter prediction signal to the prediction control unit 128.

The motion information used for motion compensation is signaled. A motion vector predictor may be used for signalizing the motion vector. That is, the difference between the motion vector and the predicted motion vector may be signaled.

Note that an inter prediction signal may be generated using not only the motion information of the current block obtained by motion search but also the motion information of adjacent blocks. Specifically, the inter prediction signal is generated in units of sub-blocks in the current block by weighted addition of the prediction signal based on the motion information obtained by motion search and the prediction signal based on the motion information of adjacent blocks. May be. Such inter prediction (motion compensation) is sometimes called OBMC (overlapped block motion compensation).

In such an OBMC mode, information indicating the size of a sub-block for OBMC (for example, called OBMC block size) is signaled at the sequence level. Also, information indicating whether or not to apply the OBMC mode (for example, referred to as an OBMC flag) is signaled at the CU level. Note that the level of signalization of these information does not need to be limited to the sequence level and the CU level, and may be other levels (for example, a picture level, a slice level, a tile level, a CTU level, or a sub-block level). Good.

The OBMC mode will be described more specifically. FIG. 5B and FIG. 5C are a flowchart and a conceptual diagram for explaining the outline of the predicted image correction process by the OBMC process.

First, a prediction image (Pred) by normal motion compensation is acquired using a motion vector (MV) assigned to an encoding target block.

Next, a prediction image (Pred_L) is obtained by applying the motion vector (MV_L) of the encoded left adjacent block to the encoding target block, and prediction is performed by superimposing the prediction image and Pred_L with weights. Perform the first correction of the image.

Similarly, the motion vector (MV_U) of the encoded upper adjacent block is applied to the block to be encoded to obtain a prediction image (Pred_U), and the prediction image and Pred_U that have been subjected to the first correction are weighted. Then, the second correction of the predicted image is performed by superimposing and making it the final predicted image.

Although the two-step correction method using the left adjacent block and the upper adjacent block has been described here, the correction may be performed more times than the two steps using the right adjacent block and the lower adjacent block. Is possible.

Note that the area to be overlapped may not be the pixel area of the entire block, but only a part of the area near the block boundary.

Note that here, the predicted image correction processing from one reference picture has been described, but the same applies to the case where a predicted image is corrected from a plurality of reference pictures, and after obtaining a corrected predicted image from each reference picture. Then, the obtained predicted image is further superimposed to obtain a final predicted image.

The processing target block may be a prediction block unit or a sub-block unit obtained by further dividing the prediction block.

As a method for determining whether or not to apply the OBMC process, for example, there is a method of using obmc_flag which is a signal indicating whether or not to apply the OBMC process. As a specific example, in the encoding apparatus, it is determined whether or not the encoding target block belongs to a complex motion region, and if it belongs to a complex motion region, a value 1 is set as obmc_flag. Encoding is performed by applying the OBMC process, and if it does not belong to a complex region of motion, the value 0 is set as obmc_flag and the encoding is performed without applying the OBMC process. On the other hand, in the decoding apparatus, by decoding the obmc_flag described in the stream, decoding is performed by switching whether to apply the OBMC process according to the value.

Note that the motion information may be derived on the decoding device side without being converted into a signal. For example, H.M. A merge mode defined in the H.265 / HEVC standard may be used. Further, for example, the motion information may be derived by performing motion search on the decoding device side. In this case, motion search is performed without using the pixel value of the current block.

Here, a mode in which motion search is performed on the decoding device side will be described. The mode in which motion search is performed on the decoding device side is sometimes called a PMMVD (patterned motion vector derivation) mode or an FRUC (frame rate up-conversion) mode.

An example of FRUC processing is shown in FIG. 5D. First, by referring to the motion vector of an encoded block spatially or temporally adjacent to the current block, a list of a plurality of candidates each having a predicted motion vector (may be common with the merge list) is generated Is done. Next, the best candidate MV is selected from a plurality of candidate MVs registered in the candidate list. For example, the evaluation value of each candidate included in the candidate list is calculated, and one candidate is selected based on the evaluation value.

Then, a motion vector for the current block is derived based on the selected candidate motion vector. Specifically, for example, the selected candidate motion vector (best candidate MV) is directly derived as a motion vector for the current block. Further, for example, the motion vector for the current block may be derived by performing pattern matching in the peripheral region at the position in the reference picture corresponding to the selected candidate motion vector. That is, the same method is used to search the area around the best candidate MV, and if there is an MV with a good evaluation value, the best candidate MV is updated to the MV, and the current block is updated. The final MV may be used. It is also possible to adopt a configuration in which the processing is not performed.

The same processing may be performed when processing is performed in units of sub-blocks.

Note that the evaluation value is calculated by obtaining a difference value of the reconstructed image by pattern matching between a region in the reference picture corresponding to the motion vector and a predetermined region. Note that the evaluation value may be calculated using information other than the difference value.

As the pattern matching, the first pattern matching or the second pattern matching is used. The first pattern matching and the second pattern matching may be referred to as bilateral matching and template matching, respectively.

In the first pattern matching, pattern matching is performed between two blocks in two different reference pictures that follow the motion trajectory of the current block. Therefore, in the first pattern matching, a region in another reference picture along the motion trajectory of the current block is used as the predetermined region for calculating the candidate evaluation value described above.

FIG. 6 is a diagram for explaining an example of pattern matching (bilateral matching) between two blocks along a motion trajectory. As shown in FIG. 6, in the first pattern matching, two blocks along the motion trajectory of the current block (Cur block) and two blocks in two different reference pictures (Ref0, Ref1) are used. By searching for the best matching pair, two motion vectors (MV0, MV1) are derived. Specifically, for the current block, a reconstructed image at a designated position in the first encoded reference picture (Ref0) designated by the candidate MV, and a symmetric MV obtained by scaling the candidate MV at a display time interval. The difference from the reconstructed image at the designated position in the second encoded reference picture (Ref1) designated in (2) is derived, and the evaluation value is calculated using the obtained difference value. The candidate MV having the best evaluation value among the plurality of candidate MVs may be selected as the final MV.

Under the assumption of continuous motion trajectory, the motion vectors (MV0, MV1) pointing to the two reference blocks are temporal distances between the current picture (Cur Pic) and the two reference pictures (Ref0, Ref1). It is proportional to (TD0, TD1). For example, when the current picture is temporally located between two reference pictures and the temporal distances from the current picture to the two reference pictures are equal, the first pattern matching uses a mirror-symmetric bi-directional motion vector Is derived.

In the second pattern matching, pattern matching is performed between a template in the current picture (a block adjacent to the current block in the current picture (for example, an upper and / or left adjacent block)) and a block in the reference picture. Therefore, in the second pattern matching, a block adjacent to the current block in the current picture is used as the predetermined region for calculating the candidate evaluation value described above.

FIG. 7 is a diagram for explaining an example of pattern matching (template matching) between a template in the current picture and a block in the reference picture. As shown in FIG. 7, in the second pattern matching, the current block is searched by searching the reference picture (Ref0) for the block that most closely matches the block adjacent to the current block (Cur block) in the current picture (Cur Pic). Of motion vectors are derived. Specifically, with respect to the current block, the reconstructed image of the encoded region of the left adjacent area and / or the upper adjacent area, and the equivalent in the encoded reference picture (Ref0) designated by the candidate MV When a difference from the reconstructed image at the position is derived, an evaluation value is calculated using the obtained difference value, and a candidate MV having the best evaluation value among a plurality of candidate MVs is selected as the best candidate MV. Good.

Information indicating whether or not to apply such FRUC mode (for example, called FRUC flag) is signaled at the CU level. In addition, when the FRUC mode is applied (for example, when the FRUC flag is true), information indicating the pattern matching method (first pattern matching or second pattern matching) (for example, called the FRUC mode flag) is signaled at the CU level. It becomes. Note that the signalization of these pieces of information need not be limited to the CU level, but may be other levels (for example, sequence level, picture level, slice level, tile level, CTU level, or sub-block level). .

Here, a mode for deriving a motion vector based on a model assuming constant velocity linear motion will be described. This mode may be referred to as a BIO (bi-directional optical flow) mode.

FIG. 8 is a diagram for explaining a model assuming constant velocity linear motion. In FIG. 8, (v _x , v _y ) indicates a velocity vector, and τ ₀ and τ ₁ are the time between the current picture (Cur Pic) and two reference pictures (Ref ₀ , Ref ₁ ), respectively. The distance. (MVx ₀ , MVy ₀ ) indicates a motion vector corresponding to the reference picture Ref ₀ , and (MVx ₁ , MVy ₁ ) indicates a motion vector corresponding to the reference picture Ref ₁ .

At this time, under the assumption of constant velocity linear motion of the velocity vector (v _x , v _y ), (MVx ₀ , MVy ₀ ) and (MVx ₁ , MVy ₁ ) are (v _x τ ₀ , v _y τ), respectively. ₀ ) and (−v _x τ ₁ , −v _y τ ₁ ), and the following optical flow equation (1) holds.

Here, I ^(k) represents the luminance value of the reference image k (k = 0, 1) after motion compensation. This optical flow equation consists of (i) the product of the time derivative of the luminance value, (ii) the horizontal component of the horizontal velocity and the spatial gradient of the reference image, and (iii) the vertical velocity and the spatial gradient of the reference image. Indicates that the sum of the products of the vertical components of is equal to zero. Based on a combination of this optical flow equation and Hermite interpolation, a block-based motion vector obtained from a merge list or the like is corrected in pixel units.

Note that the motion vector may be derived on the decoding device side by a method different from the derivation of the motion vector based on the model assuming constant velocity linear motion. For example, a motion vector may be derived for each subblock based on the motion vectors of a plurality of adjacent blocks.

Here, a mode for deriving a motion vector for each sub-block based on the motion vectors of a plurality of adjacent blocks will be described. This mode may be referred to as an affine motion compensation prediction mode.

FIG. 9A is a diagram for explaining derivation of a motion vector in units of sub-blocks based on motion vectors of a plurality of adjacent blocks. In FIG. 9A, the current block includes 16 4 × 4 sub-blocks. Here, the motion vector v ₀ of the upper left corner control point of the current block is derived based on the motion vector of the adjacent block, and the motion vector v ₁ of the upper right corner control point of the current block is derived based on the motion vector of the adjacent sub block. Is done. Then, using the two motion vectors v ₀ and v ₁ , the motion vector (v _x , v _y ) of each sub-block in the current block is derived by the following equation (2).

Here, x and y indicate the horizontal position and vertical position of the sub-block, respectively, and w indicates a predetermined weight coefficient.

Such an affine motion compensation prediction mode may include several modes in which the motion vector derivation methods of the upper left and upper right corner control points are different. Information indicating such an affine motion compensation prediction mode (for example, called an affine flag) is signaled at the CU level. Note that the information indicating the affine motion compensation prediction mode need not be limited to the CU level, but other levels (for example, sequence level, picture level, slice level, tile level, CTU level, or sub-block level). ).

[Prediction control unit]
The prediction control unit 128 selects either the intra prediction signal or the inter prediction signal, and outputs the selected signal to the subtraction unit 104 and the addition unit 116 as a prediction signal.

Here, an example of deriving the motion vector of the encoding target picture by the merge mode will be described. FIG. 9B is a diagram for explaining the outline of the motion vector deriving process in the merge mode.

First, a prediction MV list in which prediction MV candidates are registered is generated. As prediction MV candidates, spatial adjacent prediction MVs that are MVs of a plurality of encoded blocks located spatially around the encoding target block, and the position of the encoding target block in the encoded reference picture are projected. Temporal adjacent prediction MV that is MV of neighboring blocks, combined prediction MV that is MV generated by combining MV values of spatial adjacent prediction MV and temporal adjacent prediction MV, zero prediction MV that is MV having a value of zero, and the like There is.

Next, by selecting one prediction MV from a plurality of prediction MVs registered in the prediction MV list, it is determined as the MV of the block to be encoded.

Further, the variable length encoding unit describes and encodes merge_idx which is a signal indicating which prediction MV is selected in the stream.

Note that the prediction MV registered in the prediction MV list described with reference to FIG. 9B is an example, and the number of prediction MVs may be different from the number in the figure, or may not include some types of prediction MVs in the figure. It may be the composition which added prediction MV other than the kind of prediction MV in a figure.

It should be noted that the final MV may be determined by performing DMVR processing, which will be described later, using the MV of the encoding target block derived by the merge mode.

Here, an example in which MV is determined using DMVR processing will be described.

FIG. 9C is a conceptual diagram for explaining an outline of DMVR processing.

First, the optimal MVP set in the processing target block is set as a candidate MV, and reference pixels from a first reference picture that is a processed picture in the L0 direction and a second reference picture that is a processed picture in the L1 direction are set according to the candidate MV. Are obtained, and a template is generated by taking the average of each reference pixel.

Next, using the template, the peripheral areas of the candidate MVs of the first reference picture and the second reference picture are searched, respectively, and the MV with the lowest cost is determined as the final MV. The cost value is calculated using a difference value between each pixel value of the template and each pixel value of the search area, an MV value, and the like.

Note that the outline of the processing described here is basically the same in the encoding device and the decoding device.

Note that other processes may be used as long as they are processes that can search the vicinity of the candidate MV and derive the final MV, instead of the process described here.

Here, a mode for generating a predicted image using LIC processing will be described.

FIG. 9D is a diagram for explaining an outline of a predicted image generation method using luminance correction processing by LIC processing.

First, an MV for obtaining a reference image corresponding to a block to be encoded is derived from a reference picture that is an encoded picture.

Next, for the encoding target block, reference is made using the luminance pixel values of the left and upper adjacent encoded peripheral reference regions and the luminance pixel value at the equivalent position in the reference picture specified by MV. Information indicating how the luminance value has changed between the picture and the picture to be encoded is extracted to calculate a luminance correction parameter.

The predicted image for the encoding target block is generated by performing the brightness correction process using the brightness correction parameter for the reference image in the reference picture specified by MV.

Note that the shape of the peripheral reference region in FIG. 9D is an example, and other shapes may be used.

Further, here, the process of generating a predicted image from one reference picture has been described, but the same applies to the case of generating a predicted image from a plurality of reference pictures, and the same applies to reference images acquired from each reference picture. The predicted image is generated after performing the luminance correction processing by the method.

As a method for determining whether to apply LIC processing, for example, there is a method of using lic_flag, which is a signal indicating whether to apply LIC processing. As a specific example, in the encoding device, it is determined whether or not the encoding target block belongs to an area where the luminance change occurs, and if it belongs to the area where the luminance change occurs, lic_flag is set. Encode by applying LIC processing with a value of 1 set, and if not belonging to an area where a luminance change has occurred, set 0 as lic_flag and perform encoding without applying the LIC processing . On the other hand, in the decoding device, by decoding lic_flag described in the stream, decoding is performed by switching whether to apply the LIC processing according to the value.

As another method for determining whether or not to apply LIC processing, for example, there is a method for determining whether or not LIC processing has been applied to peripheral blocks. As a specific example, when the encoding target block is in the merge mode, whether or not the surrounding encoded blocks selected in the derivation of the MV in the merge mode processing are encoded by applying the LIC processing. Judgment is performed, and encoding is performed by switching whether to apply the LIC processing according to the result. In this example, the decoding process is exactly the same.

[Outline of Decoding Device]
Next, an outline of a decoding apparatus capable of decoding the encoded signal (encoded bit stream) output from the encoding apparatus 100 will be described. FIG. 10 is a block diagram showing a functional configuration of decoding apparatus 200 according to Embodiment 1. The decoding device 200 is a moving image / image decoding device that decodes moving images / images in units of blocks.

As illustrated in FIG. 10, the decoding device 200 includes an entropy decoding unit 202, an inverse quantization unit 204, an inverse transformation unit 206, an addition unit 208, a block memory 210, a loop filter unit 212, and a frame memory 214. And an intra prediction unit 216, an inter prediction unit 218, and a prediction control unit 220.

The decoding device 200 is realized by, for example, a general-purpose processor and a memory. In this case, when the software program stored in the memory is executed by the processor, the processor executes the entropy decoding unit 202, the inverse quantization unit 204, the inverse transformation unit 206, the addition unit 208, the loop filter unit 212, and the intra prediction unit. 216, the inter prediction unit 218, and the prediction control unit 220. Also, the decoding apparatus 200 is dedicated to the entropy decoding unit 202, the inverse quantization unit 204, the inverse transformation unit 206, the addition unit 208, the loop filter unit 212, the intra prediction unit 216, the inter prediction unit 218, and the prediction control unit 220. It may be realized as one or more electronic circuits.

Hereinafter, each component included in the decoding device 200 will be described.

[Entropy decoding unit]
The entropy decoding unit 202 performs entropy decoding on the encoded bit stream. Specifically, the entropy decoding unit 202 performs arithmetic decoding from a coded bitstream to a binary signal, for example. Then, the entropy decoding unit 202 debinarizes the binary signal. As a result, the entropy decoding unit 202 outputs the quantized coefficient to the inverse quantization unit 204 in units of blocks.

[Inverse quantization unit]
The inverse quantization unit 204 inversely quantizes the quantization coefficient of a decoding target block (hereinafter referred to as a current block) that is an input from the entropy decoding unit 202. Specifically, the inverse quantization unit 204 inversely quantizes each quantization coefficient of the current block based on the quantization parameter corresponding to the quantization coefficient. Then, the inverse quantization unit 204 outputs the quantization coefficient (that is, the transform coefficient) obtained by inverse quantization of the current block to the inverse transform unit 206.

[Inverse conversion part]
The inverse transform unit 206 restores the prediction error by inverse transforming the transform coefficient that is an input from the inverse quantization unit 204.

For example, when the information read from the encoded bit stream indicates that EMT or AMT is applied (for example, the AMT flag is true), the inverse conversion unit 206 determines the current block based on the information indicating the read conversion type. Inversely transform the conversion coefficient of.

Also, for example, when the information read from the encoded bitstream indicates that NSST is applied, the inverse transform unit 206 applies inverse retransformation to the transform coefficient.

[Addition part]
The adder 208 reconstructs the current block by adding the prediction error input from the inverse converter 206 and the prediction sample input from the prediction controller 220. Then, the adding unit 208 outputs the reconfigured block to the block memory 210 and the loop filter unit 212.

[Block memory]
The block memory 210 is a storage unit for storing a block that is referred to in intra prediction and that is within a decoding target picture (hereinafter referred to as a current picture). Specifically, the block memory 210 stores the reconstructed block output from the adding unit 208.

[Loop filter section]
The loop filter unit 212 applies a loop filter to the block reconstructed by the adding unit 208, and outputs the filtered reconstructed block to the frame memory 214, the display device, and the like.

If the ALF on / off information read from the encoded bitstream indicates ALF on, one filter is selected from the plurality of filters based on the local gradient direction and activity, The selected filter is applied to the reconstruction block.

[Frame memory]
The frame memory 214 is a storage unit for storing a reference picture used for inter prediction, and is sometimes called a frame buffer. Specifically, the frame memory 214 stores the reconstructed block filtered by the loop filter unit 212.

[Intra prediction section]
The intra prediction unit 216 performs intra prediction with reference to the block in the current picture stored in the block memory 210 based on the intra prediction mode read from the encoded bitstream, so that a prediction signal (intra prediction Signal). Specifically, the intra prediction unit 216 generates an intra prediction signal by performing intra prediction with reference to a sample (for example, luminance value and color difference value) of a block adjacent to the current block, and performs prediction control on the intra prediction signal. Output to the unit 220.

In addition, when the intra prediction mode that refers to the luminance block is selected in the intra prediction of the color difference block, the intra prediction unit 216 may predict the color difference component of the current block based on the luminance component of the current block. .

In addition, when the information read from the encoded bitstream indicates application of PDPC, the intra prediction unit 216 corrects the pixel value after intra prediction based on the gradient of the reference pixel in the horizontal / vertical direction.

[Inter prediction section]
The inter prediction unit 218 refers to the reference picture stored in the frame memory 214 and predicts the current block. Prediction is performed in units of a current block or a sub-block (for example, 4 × 4 block) in the current block. For example, the inter prediction unit 218 generates an inter prediction signal of the current block or sub-block by performing motion compensation using motion information (for example, a motion vector) read from the encoded bitstream, and generates the inter prediction signal. The result is output to the prediction control unit 220.

When the information read from the encoded bitstream indicates that the OBMC mode is to be applied, the inter prediction unit 218 includes not only the motion information of the current block obtained by motion search but also the motion information of adjacent blocks. To generate an inter prediction signal.

Also, when the information read from the encoded bitstream indicates that the FRUC mode is applied, the inter prediction unit 218 follows the pattern matching method (bilateral matching or template matching) read from the encoded stream. Motion information is derived by performing motion search. Then, the inter prediction unit 218 performs motion compensation using the derived motion information.

In addition, when the BIO mode is applied, the inter prediction unit 218 derives a motion vector based on a model assuming constant velocity linear motion. Also, when the information read from the encoded bitstream indicates that the affine motion compensated prediction mode is applied, the inter prediction unit 218 determines the motion vector in units of subblocks based on the motion vectors of a plurality of adjacent blocks. Is derived.

[Prediction control unit]
The prediction control unit 220 selects either the intra prediction signal or the inter prediction signal, and outputs the selected signal to the adding unit 208 as a prediction signal.

[Inter-screen prediction performed by encoding device and decoding device]
FIG. 11 is a block diagram for explaining processing related to inter-screen prediction performed by the encoding device 100 shown in FIG. For example, the input image is divided into blocks by the dividing unit 102 shown in FIG. Then, processing is performed for each block.

The subtraction unit 104 generates a difference image by acquiring a difference between the input image in block units and a prediction image generated by intra prediction or inter prediction. Then, the conversion unit 106 and the quantization unit 108 generate a coefficient signal by performing conversion and quantization on the difference image. The entropy encoding unit 110 generates an encoded stream (encoded bit stream) by performing entropy encoding on the generated coefficient signal and other encoded signals.

Meanwhile, the inverse quantization unit 112 and the inverse transform unit 114 restore the difference image by performing inverse quantization and inverse transform on the generated coefficient signal. The intra prediction unit (intra prediction unit) 124 generates a prediction image by intra prediction, and the inter prediction unit (inter prediction unit) 126 generates a prediction image by inter prediction. The adding unit 116 generates a reconstructed image by adding one of the predicted image generated by the intra-screen prediction and the predicted image generated by the inter-screen prediction and the restored difference image.

Also, the intra prediction unit 124 uses the reconstructed image of the processed block for intra prediction of another block to be processed later. In addition, the loop filter unit 120 applies a loop filter to the reconstructed image of the processed block, and stores the reconstructed image to which the loop filter is applied in the frame memory 122. The inter-screen prediction unit 126 uses the reconstructed image stored in the frame memory 122 for inter-screen prediction of another block in another picture to be processed later.

Also, the inter-screen prediction unit 126 performs inter-screen prediction according to the inter-screen prediction control signal set from the outside. Here, FRUC control information, sub-block processing control information, and the like are used as the inter-screen prediction control signal. Then, the entropy encoding unit 110 encodes FRUC control information, sub-block processing control information, and the like into a stream as an inter-screen prediction control signal.

The above FRUC control information is information indicating a method for deriving a motion vector. For example, FRUC control information indicates one of a plurality of methods for deriving a motion vector. The FRUC control information corresponds to information indicating whether or not to apply the FRUC mode and information indicating a pattern matching method as described above. The sub-block processing control information is information indicating whether it is effective or ineffective to perform motion compensation in units of sub-blocks constituting the block.

For example, the FRUC control information may be encoded into the header layer of the processing target block, may be encoded into the header layer of the processing target slice, or may be encoded into the header layer of the processing target picture. However, it may be encoded into the header layer of the processing target stream. Similarly, the sub-block processing control information may be encoded into the header layer of the processing target block, may be encoded into the header layer of the processing target slice, or encoded into the header layer of the processing target picture. Alternatively, it may be encoded into the header layer of the processing target stream.

Further, the inter-screen prediction control signal may be set from the outside of the encoding device 100. For example, the inter-screen prediction control signal may be determined according to processing performance. Moreover, when FRUC control information, sub-block processing control information, and the like are determined in advance, the inter-screen prediction control signal may not be used. In this case, the inter-screen prediction control signal may not be encoded.

In addition, the inter-screen prediction control signal is not limited to being set from the outside of the encoding apparatus 100, and may be set inside the encoding apparatus 100. For example, the inter-screen prediction unit 126 may set an inter-screen prediction control signal. Specifically, the inter-screen prediction unit 126 may evaluate the inter-screen prediction control signal setting candidates according to the degree of matching between the predicted image generated according to the inter-screen prediction control signal setting candidates and the input image. Then, the inter-screen prediction unit 126 may set an inter-screen prediction control signal according to the evaluation result.

Note that the degree of matching between the predicted image and the input image can be evaluated by the difference between the predicted image and the input image. The degree of matching between other images described in this embodiment and the like can be similarly evaluated based on the difference between images.

FIG. 12 is a block diagram for explaining processing related to inter-screen prediction performed by the decoding device 200 shown in FIG. The entropy decoding unit 202 performs entropy decoding on the input stream that is the encoded stream, thereby acquiring information in units of blocks. Then, processing is performed for each block.

The inverse quantization unit 204 and the inverse transform unit 206 restore the difference image by performing inverse quantization and inverse transform on the coefficient signal decoded for each block.

The intra prediction unit (intra prediction unit) 216 generates a prediction image by intra prediction, and the inter prediction unit (inter prediction unit) 218 generates a prediction image by inter prediction. The adding unit 208 generates a reconstructed image by adding one of the predicted image generated by the intra-screen prediction and the predicted image generated by the inter-screen prediction and the restored difference image.

Also, the intra-screen prediction unit 216 uses the reconstructed image of the processed block for intra-screen prediction of another block to be processed later. Further, the loop filter unit 212 applies a loop filter to the reconstructed image of the processed block, and stores the reconstructed image to which the loop filter is applied in the frame memory 214. The inter-screen prediction unit 218 uses the reconstructed image stored in the frame memory 214 for inter-screen prediction of another block in another picture to be processed later.

Also, the inter-screen prediction unit 218 performs inter-screen prediction according to the inter-screen prediction control signal acquired from the input stream by entropy decoding. Here, FRUC control information, sub-block processing control information, and the like are used as the inter-screen prediction control signal. That is, the entropy decoding unit 202 decodes FRUC control information, sub-block processing control information, and the like from the stream as inter-screen prediction control signals.

The FRUC control information may be decoded from the header layer of the processing target block, may be decoded from the header layer of the processing target slice, may be decoded from the header layer of the processing target picture, It may be decoded from the header layer of the target stream. Similarly, the sub-block processing control information may be decoded from the header layer of the processing target block, may be decoded from the header layer of the processing target slice, or may be decoded from the header layer of the processing target picture. However, it may be decoded from the header layer of the processing target stream.

Also, the inter-screen prediction control signal set in the encoding device 100 may be set from the outside of the decoding device 200. Further, when the FRUC control information, the sub-block processing control information, and the like are determined in advance in the same way in the encoding device 100 and the decoding device 200, the inter-screen prediction control signal may not be used. In this case, the inter-screen prediction control signal may not be decoded.

[Specific example of inter-screen prediction]
Hereinafter, a plurality of specific examples of inter-screen prediction will be shown. For example, one of a plurality of specific examples is applied. In the following, the operation of the encoding device 100 is mainly shown, but the operation of the decoding device 200 is basically the same. In particular, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100.

However, the encoding apparatus 100 encodes FRUC control information, sub-block processing control information, and the like used for inter-screen prediction into a stream. FRUC control information, sub-block processing control information, and the like may be set in advance from the outside, or may be set in advance by the encoding apparatus 100 itself. On the other hand, the decoding device 200 decodes FRUC control information and sub-block processing control information used for inter-screen prediction from the stream.

Also, in the normal inter-screen prediction method, the encoding apparatus 100 derives a motion vector according to the degree of matching between the image of the processing target region and the reconstructed image of the region in the reference picture, and encodes motion vector information. . On the other hand, the decoding apparatus 200 decodes motion vector information and derives a motion vector.

The above motion vector information is information related to the motion vector and directly or indirectly indicates the motion vector. For example, the motion vector information may indicate the motion vector itself, or may indicate a differential motion vector that is a difference between the motion vector and the predicted motion vector, and an identifier of the predicted motion vector. Further, the normal inter-screen prediction method may be expressed as a basic inter-screen prediction method.

In the template FRUC method and the bilateral FRUC method, the encoding device 100 and the decoding device 200 derive a motion vector without encoding and decoding motion vector information.

Specifically, in the template FRUC method, the encoding device 100 and the decoding device 200 calculate the motion vector according to the matching degree between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture. To derive. In the bilateral FRUC method, the encoding device 100 and the decoding device 200 derive a motion vector according to the degree of matching between two reconstructed images in two regions in two reference pictures.

Also, the FRUC control information in the following description indicates the normal inter-screen prediction method as 0, the template FRUC method as 1, and the bilateral FRUC method as 2. However, these numbers and classifications are examples, and numbers and classifications different from these numbers and classifications may be used.

Further, the sub-block processing control information in the following description indicates that it is effective to perform motion compensation in units of sub-blocks, and indicates that it is invalid to perform motion compensation in units of sub-blocks. As shown. However, these numbers are examples, and numbers different from these numbers may be used.

In the following, processing performed for each block is shown. This block is also referred to as a prediction block. The block may be an image data unit to be encoded and decoded, or may be an image data unit to be reconstructed. And the subblock which comprises a block may be defined by predetermined size. The sub-block may be composed of 16 pixels of 4 × 4, for example. Then, one or more sub-blocks constituting the block may be determined by dividing the block by a predetermined size.

FIG. 13 is a flowchart illustrating a first specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100.

As shown in FIG. 13, the inter-screen prediction unit 126 performs processing for each block. For example, when the FRUC control information indicates 0 (0 in S101), the inter-screen prediction unit 126 derives a block-based motion vector (MV) according to the normal inter-screen prediction method (S111). Then, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of blocks using the motion vectors in units of blocks as they are (S117).

If the FRUC control information indicates 1 (1 in S101), the inter-screen prediction unit 126 derives a motion vector in block units according to the template FRUC method (S121). When the FRUC control information indicates 2 (2 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the bilateral FRUC method (S131).

The inter-screen prediction unit 126 derives a motion vector in units of blocks according to the template FRUC method or the bilateral method, and then derives a motion vector in units of sub-blocks according to the bilateral method (S136). At this time, for example, the inter-screen prediction unit 126 derives a motion vector in units of sub-blocks using the motion vector in units of blocks. More specifically, the inter-screen prediction unit 126 uses a motion vector in units of blocks as a candidate motion vector for a motion vector in units of sub-blocks.

In the derivation of the motion vector in units of sub-blocks, the bilateral FRUC method is applied regardless of whether the method for deriving the motion vector in block units is the template FRUC method or the bilateral FRUC method. That is, even if the template FRUC method is applied to the derivation of the motion vector for each block, the bilateral FRUC method is applied to the derivation of the motion vector for each sub-block.

Then, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of sub-blocks using the motion vector in units of sub-blocks (S137). The inter-screen prediction unit 126 then repeats derivation of motion vectors (S136) and motion compensation (S137) for each sub-block in the block.

In the template FRUC method, a reconstructed image of an area adjacent to the processing target area is used to derive a motion vector of the processing target area. On the other hand, when processing is performed in units of sub-blocks, there is a possibility that a reconstructed image of an area adjacent to the processing target sub-block has not yet been generated. Therefore, a reconstructed image for deriving a motion vector according to the template FRUC method is not generated, and there is a possibility that a sub-block unit motion vector is not properly derived according to the template FRUC method.

Therefore, in this specific example, the bilateral FRUC method is applied instead of the template FRUC method for deriving motion vectors in units of sub-blocks. Thereby, the motion vector of a subblock unit can be derived | led-out appropriately according to the bilateral FRUC system.

In this specific example, when a block-based motion vector is derived according to the template FRUC method or the bilateral FRUC method, a sub-block-based motion vector is derived according to the bilateral FRUC method. However, the present invention is not limited to this, and when a motion vector in units of blocks is derived according to the normal inter-screen prediction method, a motion vector in units of sub-blocks may be derived according to the bilateral FRUC method.

FIG. 14 is a flowchart illustrating a second specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100. In this specific example, when the FRUC control information indicates 0 or 2 (0 or 2 in S101), the inter-screen prediction unit 126 operates in the same manner as in the first specific example.

When the FRUC control information indicates 1 (1 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the template FRUC method (S121).

Then, the inter-screen prediction unit 126 determines whether or not the motion vector derived as the block-based motion vector according to the template FRUC method is a motion vector for bidirectional prediction (S122). In other words, the inter-screen prediction unit 126 determines whether the motion vector for each block is a bidirectional motion vector or a unidirectional motion vector.

When it is determined that the motion vector in block units is a unidirectional motion vector (No in S122), the inter-screen prediction unit 126 performs motion compensation in block units using the block motion vectors as they are. Perform (S117). Thereby, the inter-screen prediction unit 126 generates an inter-screen prediction image.

On the other hand, when it is determined that the motion vector in units of blocks is a motion vector for bidirectional prediction (Yes in S122), the inter-screen prediction unit 126, in the same way as in the first specific example, performs sub-block units in accordance with the bilateral method. The motion vector is derived (S136). Then, similarly to the first specific example, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of sub-blocks using motion vectors in units of sub-blocks (S137).

In the bilateral FRUC method, bi-predictive motion vectors are derived using bi-predictive motion vector candidates. Therefore, when a motion vector derived as a block-based motion vector according to the template FRUC method is a unidirectional prediction motion vector, it is not used as a candidate as it is.

Therefore, in this specific example, when a motion vector derived as a block-unit motion vector according to the template FRUC method is a unidirectional motion vector, a sub-block unit motion vector is not derived according to the bilateral FRUC method. Then, motion compensation is performed in units of blocks using the motion vectors in units of blocks.

On the other hand, when a motion vector derived as a block-unit motion vector according to the template FRUC method is a bidirectional prediction motion vector, a sub-block unit motion vector is derived according to the bilateral FRUC method. Then, motion compensation is performed in units of subblocks using motion vectors in units of subblocks.

Thereby, when the motion vector in units of blocks is suitable for a candidate for deriving the motion vector in units of sub-blocks according to the bilateral FRUC method, the motion vectors in units of sub-blocks can be derived according to the bilateral FRUC method. Therefore, a sub-block unit motion vector can be appropriately derived according to the bilateral FRUC method.

In this specific example, when a motion vector in block units is derived according to the template FRUC method, whether or not processing is performed in subblock units is controlled according to bi-directional prediction or uni-directional prediction. The present invention is not limited to this, and even when a motion vector in block units is derived according to the normal inter-screen prediction method, whether or not to perform processing in sub-block units may be controlled according to bidirectional prediction or unidirectional prediction. .

FIG. 15 is a flowchart illustrating a third specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100. In this specific example, when the FRUC control information is 0 (0 in S101), the inter-screen prediction unit 126 operates in the same manner as in the first specific example.

Similarly to the first specific example, when the FRUC control information indicates 1 (1 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the template FRUC method (S121). When the FRUC control information indicates 2 (2 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the bilateral FRUC method (S131).

Furthermore, in this example, the inter-screen prediction unit 126 determines whether the sub-block processing control information indicates 0 or 1 after deriving a motion vector for each block according to the template FRUC method or the bilateral method (S133). ). As described above, here, the sub-block processing control information indicates that it is effective to perform motion compensation in units of sub-blocks, and that it is invalid to perform motion compensation in units of sub-blocks. Shown as 0.

When the sub-block processing control information indicates 0 (0 in S133), the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of blocks using the motion vector in units of blocks as it is. (S117).

On the other hand, when the sub-block processing control information indicates 1 (1 in S133), the inter-screen prediction unit 126 derives a motion vector in units of sub-blocks according to the bilateral method as in the first specific example (S136). Then, similarly to the first specific example, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of sub-blocks using motion vectors in units of sub-blocks (S137).

In this specific example, the encoding apparatus 100 can flexibly switch between performing motion compensation in units of sub-blocks and performing motion compensation in units of blocks. Then, the encoding apparatus 100 and the decoding apparatus 200 perform motion compensation in units of subblocks in the same way between the encoding apparatus 100 and the decoding apparatus 200 by encoding and decoding the subblock processing control information, or in units of blocks. To switch between motion compensation.

FIG. 16 is a flowchart illustrating a fourth specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100. In this specific example, when the FRUC control information is 0 or 2 (0 or 2 in S101), the inter-screen prediction unit 126 operates in the same manner as in the third specific example.

Also, as in the second specific example, when the FRUC control information indicates 1 (1 in S101), the inter-screen prediction unit 126 derives a motion vector in block units according to the template FRUC method (S121). Then, the inter-screen prediction unit 126 determines whether or not the motion vector derived as a block-based motion vector according to the template FRUC method is a motion vector for bidirectional prediction (S122).

If it is determined that the motion vector in units of blocks is a unidirectional motion vector (No in S122), the inter-screen prediction unit 126 operates in the same manner as in the second specific example. On the other hand, when it is determined that the motion vector in units of blocks is a motion vector for bidirectional prediction (Yes in S122), the inter-screen prediction unit 126 operates in the same manner as in the third specific example.

In this specific example, the second specific example and the third specific example are combined. As a result, when the block-based motion vector is suitable for a candidate for deriving the sub-block unit motion vector according to the bilateral FRUC method, the sub-block unit motion vector can be derived according to the bilateral FRUC method. Also, it is possible to flexibly switch between performing motion compensation in units of sub-blocks and performing motion compensation in units of blocks.

In this specific example, when a block-based motion vector is derived according to the template FRUC method, whether to perform processing in subblock units according to bi-directional prediction or unidirectional prediction and sub-block processing control information. Is controlled. Not only this, but also when motion vectors in block units are derived according to the normal inter-screen prediction method, whether to perform processing in sub-block units according to bi-directional prediction or uni-directional prediction and sub-block processing control information Whether or not may be controlled.

FIG. 17 is a flowchart illustrating a fifth specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100. In this specific example, when the FRUC control information is 1 or 2 (1 or 2 in S101), the inter-screen prediction unit 126 operates in the same manner as in the third specific example.

Further, when the FRUC control information indicates 0 (0 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the normal inter-screen prediction method (S111). Then, the inter-screen prediction unit 126 determines whether the sub-block processing control information indicates 0 or 1 after deriving a motion vector for each block according to the normal inter-screen prediction method (S133).

On the other hand, when the sub-block processing control information indicates 1 (1 in S133), the inter-screen prediction unit 126 derives a motion vector for each sub-block according to the bilateral method (S136). At that time, in the first specific example, the inter-screen prediction unit 126 derives a motion vector for each sub-block according to the bilateral method, similarly to the process for deriving the motion vector for each sub-block according to the bilateral method.

Then, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of sub-blocks using the motion vector in units of sub-blocks (S137).

In this specific example, not only the template FRUC method and the bilateral FRUC method but also the normal inter-screen prediction method can be flexibly switched between performing motion compensation in sub-block units or performing motion compensation in block units.

FIG. 18 is a flowchart illustrating a sixth specific example of inter-screen prediction performed by the inter-screen prediction unit 126 of the encoding device 100. As described above, the inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100. In this specific example, when the FRUC control information is 0 or 2 (0 or 2 in S101), the inter-screen prediction unit 126 operates in the same manner as in the third specific example.

Also, as in the third specific example, when the FRUC control information indicates 1 (1 in S101), the inter-screen prediction unit 126 derives a block-based motion vector according to the template FRUC method (S121).

Then, the inter-screen prediction unit 126 determines whether the sub-block processing control information indicates 0 or 1 after deriving the motion vector for each block according to the template FRUC method (S123). As described above, here, the sub-block processing control information indicates that it is effective to perform motion compensation in units of sub-blocks, and that it is invalid to perform motion compensation in units of sub-blocks. Shown as 0.

When the sub-block processing control information indicates 0 (0 in S123), the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of blocks using the motion vector in units of blocks as it is. (S117).

On the other hand, when the sub-block processing control information indicates 1 (1 in S123), the inter-screen prediction unit 126 derives a motion vector for each sub-block according to the template method (S126). At this time, for example, the inter-screen prediction unit 126 derives a motion vector in units of sub-blocks using the motion vector in units of blocks. More specifically, the inter-screen prediction unit 126 uses a motion vector in units of blocks as a candidate motion vector for a motion vector in units of sub-blocks.

Then, the inter-screen prediction unit 126 obtains an inter-screen prediction image by performing motion compensation in units of sub-blocks using the motion vector in units of sub-blocks (S127). Then, the inter-screen prediction unit 126 repeats motion vector derivation (S126) and motion compensation (S127) for each sub-block in the block.

In this specific example, similarly to the third specific example, when a block-unit motion vector is derived according to the template FRUC method or the bilateral FRUC method, whether or not the processing is performed in subblock units according to the subblock processing control information. Is controlled.

Then, when a motion vector for each block is derived according to the template FRUC method and processing is performed for each sub-block, a motion vector for each sub-block is derived according to the template FRUC method. In addition, when a motion vector for each block is derived according to the bilateral FRUC scheme and processing is performed for each subblock, a motion vector for each subblock is derived according to the bilateral FRUC scheme.

Thereby, the template FRUC method or the bilateral FRUC method can be applied adaptively as a method used for deriving a motion vector in units of sub-blocks.

In the description of FIGS. 13 to 18, one method used for deriving a motion vector in units of blocks is selected from the three methods of the normal inter-screen prediction method, the template FRUC method, and the bilateral FRUC method. Yes. However, one method used for deriving a motion vector in units of blocks may be selected from four or more methods including another method different from these three methods.

And, for example, the other method may be handled in the same manner as one of the three methods. Specifically, even when a block-based motion vector is derived according to another scheme, sub-block processing control information may be used to determine whether to perform motion compensation in units of sub-blocks. In addition, when a motion vector in units of blocks is derived according to another scheme, whether or not the motion vector in units of blocks is a bi-predictive motion vector in determining whether to perform motion compensation in units of sub-blocks. May be used.

For example, as another method described above, there is a merge mode method for deriving a motion vector of a region spatially or temporally adjacent to a processing target region as a motion vector of the processing target region. In addition, there are other methods using affine transformation.

Also, the selection range may be narrowed down to one or more of the above four or more methods. For example, one method used for deriving a motion vector in units of blocks may be selected from two predetermined methods. Specifically, one method may be selected from the normal inter-screen prediction method and the template FRUC method, or one method may be selected from the normal inter-screen prediction method and the bilateral FRUC method. . Alternatively, one method may be selected from the template FRUC method and the bilateral FRUC method.

Alternatively, one method used for deriving a motion vector in units of blocks may be determined in advance. For example, as one method used for deriving motion vectors in block units, a normal inter-screen prediction method may be determined in advance, a template FRUC method may be determined in advance, or a bilateral method may be determined in advance. It may be determined.

The bidirectional prediction described here may be bidirectional prediction using the previous reference picture and the subsequent reference picture in the display order, or may be bidirectional prediction using the two previous reference pictures in the display order. Alternatively, bi-directional prediction using the two subsequent reference pictures in the display order may be used. That is, in bi-directional prediction, the previous reference picture and the subsequent reference picture may be used in the display order, the two previous reference pictures may be used in the display order, or the subsequent reference pictures may be used in the display order. Two reference pictures may be used.

In addition, when it is determined that motion compensation is not performed in units of subblocks regardless of the subblock processing control information, the subblock processing control information may not be encoded or decoded.

For example, in the third specific example of FIG. 15, when the motion vector in units of blocks is derived by the normal inter-screen prediction method, the sub-block processing control information may not be encoded or decoded. Further, in the fourth specific example of FIG. 16, when a block-unit motion vector is derived by the template FRUC method and the block-unit motion vector is a unidirectional motion vector, the sub-block processing control information is encoded. It does not have to be or may not be decoded.

[Template FRUC method and bilateral FRUC method]
Hereinafter, a method for deriving a motion vector according to the template FRUC method or the bilateral FRUC method will be described. A method for deriving a motion vector in units of blocks and a method for deriving a motion vector in units of sub-blocks are basically the same. In the following description, a method for deriving a motion vector of a block and a method for deriving a motion vector of a sub-block will be described as methods for deriving a motion vector of a processing target region.

FIG. 19 is a conceptual diagram showing a template FRUC method used for derivation of a motion vector of a processing target area in the encoding device 100 and the decoding device 200. In the template FRUC method, a motion vector is derived using a common method between the encoding device 100 and the decoding device 200 without encoding and decoding of motion vector information of the processing target region.

In the template FRUC method, a motion vector is derived using a reconstructed image of an adjacent region that is a region adjacent to the processing target region and a reconstructed image of a corresponding adjacent region that is a region in the reference picture.

Here, the adjacent region is one or both of the region adjacent to the left and the region adjacent above the processing target region.

Also, the corresponding adjacent region is a region specified using a candidate motion vector that is a candidate motion vector of the processing target region. Specifically, the corresponding adjacent region is a region indicated by the candidate motion vector from the adjacent region. In addition, the relative position of the corresponding adjacent area with respect to the corresponding area indicated by the candidate motion vector from the processing target area is equal to the relative position of the adjacent area with respect to the processing target area.

FIG. 20 is a conceptual diagram showing a bilateral FRUC method used in the encoding device 100 and the decoding device 200 for deriving the motion vector of the processing target region. In the bilateral FRUC method, similarly to the template FRUC method, a method common to the encoding device 100 and the decoding device 200 is used without encoding and decoding of motion vector information of the processing target region. A motion vector is derived.

Also, in the bilateral FRUC method, a motion vector is derived using two reconstructed images of two regions in two reference pictures. For example, as shown in FIG. 20, the motion vector is derived using the reconstructed image of the corresponding region in the first reference picture and the reconstructed image of the symmetric region in the second reference picture.

Here, each of the corresponding region and the symmetric region is a region specified using a candidate motion vector that is a candidate motion vector of the processing target region. Specifically, the corresponding region is a region indicated by the candidate motion vector from the processing target region. The symmetric region is a region indicated by a symmetric motion vector from the processing target region. A symmetric motion vector is a motion vector constituting a set of candidate motion vectors for bidirectional prediction. The symmetric motion vector may be a motion vector derived by scaling the candidate motion vector.

FIG. 21 is a flowchart showing an operation in which the inter-screen prediction unit 126 of the encoding apparatus 100 derives a motion vector according to the template FRUC method or the bilateral FRUC method. The inter-screen prediction unit 218 of the decoding device 200 operates in the same manner as the inter-screen prediction unit 126 of the encoding device 100.

First, the inter-screen prediction unit 126 derives a candidate motion vector by referring to each motion vector of one or more processed regions that are temporally or spatially adjacent to the processing target region.

In the bilateral FRUC method, the inter-screen prediction unit 126 derives a candidate motion vector for bidirectional prediction. That is, the inter-screen prediction unit 126 derives candidate motion vectors as a set of two motion vectors.

Specifically, in the bilateral FRUC method, when the motion vector of the processed region is a bidirectional prediction motion vector, the inter prediction unit 126 directly uses the bidirectional prediction motion vector as a candidate motion for bidirectional prediction. Derived as a vector. When the motion vector of the processed region is a unidirectional prediction motion vector, the inter-frame prediction unit 126 derives a bidirectional prediction motion vector from the unidirectional prediction motion vector by scaling or the like, thereby performing bidirectional prediction. Candidate motion vectors may be derived.

More specifically, the inter-screen prediction unit 126 derives a motion vector that refers to the second reference picture by scaling the motion vector that refers to the first reference picture according to the display time interval in the bilateral FRUC method. . Thereby, the inter-screen prediction unit 126 derives a candidate motion vector constituting a set of a motion vector for unidirectional prediction and a scaled motion vector as a candidate motion vector for bidirectional prediction.

Alternatively, in the bilateral FRUC method, the inter-frame prediction unit 126 may derive the motion vector of the processed area as a candidate motion vector when the motion vector of the processed area is a bidirectional motion vector. The inter-screen prediction unit 126 may not derive the motion vector of the processed region as a candidate motion vector when the motion vector of the processed region is a unidirectional motion vector.

In the template FRUC method, regardless of whether the motion vector of the processed region is a bidirectional prediction motion vector or a unidirectional prediction motion vector, the inter-screen prediction unit 126 derives the processed region motion vector as a candidate motion vector. To do.

Then, the inter-screen prediction unit 126 generates a candidate motion vector list composed of candidate motion vectors (S201). Here, when the processing target region is a sub-block, that is, when deriving a motion vector for each sub-block, the inter-screen prediction unit 126 includes the motion vector for each block as a candidate motion vector in the candidate motion vector list. Also good. At this time, the inter-screen prediction unit 126 may include the motion vector in units of blocks in the candidate motion vector list as the candidate motion vector having the highest priority.

Also, in the bilateral FRUC method, when the motion vector in block units is a unidirectional prediction motion vector, the inter-frame prediction unit 126 derives a bidirectional motion candidate motion vector from the unidirectional prediction motion vector by scaling or the like. May be. For example, the inter-screen prediction unit 126 may derive a candidate motion vector for bidirectional prediction by scaling or the like from the motion vector for unidirectional prediction, as in the case where the surrounding motion vector is a motion vector for unidirectional prediction. .

Then, the inter-screen prediction unit 126 may include the candidate motion vector derived as the candidate motion vector for bidirectional prediction from the motion vector for unidirectional prediction in the candidate motion vector list.

Alternatively, in the bilateral FRUC method, the inter-screen prediction unit 126 may include a motion vector in block units as a candidate motion vector in the candidate motion vector list when the motion vector in block units is a motion vector for bidirectional prediction. Good. The inter-screen prediction unit 126 may not include the block-based motion vector as a candidate motion vector in the candidate motion vector list when the block-based motion vector is a unidirectional prediction motion vector.

Then, the inter-screen prediction unit 126 selects the best candidate motion vector from one or more candidate motion vectors included in the candidate motion vector list (S202). At this time, the inter-screen prediction unit 126 calculates an evaluation value for each of one or more candidate motion vectors according to the degree of matching between the two reconstructed images in the two evaluation target regions.

Specifically, in the template FRUC method, the two evaluation target areas are an adjacent area and a corresponding adjacent area as shown in FIG. 19, and in the bilateral FRUC method, the two evaluation target areas are as shown in FIG. A region and a symmetric region. As described above, the corresponding adjacent region used in the template FRUC method, and the corresponding region and the symmetric region used in the bilateral FRUC method are determined according to the candidate motion vector.

For example, the inter-screen prediction unit 126 calculates a better evaluation value as the degree of matching between the two reconstructed images of the two evaluation target areas is higher. Specifically, the inter-screen prediction unit 126 derives a difference value between two reconstructed images of two evaluation target areas. Then, the inter-screen prediction unit 126 calculates an evaluation value using the difference value. For example, the inter-screen prediction unit 126 calculates a better evaluation value as the difference value is smaller.

Further, not only the difference value but also other information may be used for calculating the evaluation value. That is, the inter-screen prediction unit 126 may calculate the evaluation value using the difference value and other information. For example, the priority order of one or more candidate motion vectors, the code amount based on the priority order, and the like may affect the evaluation value.

Then, the inter-screen prediction unit 126 selects a candidate motion vector having the best evaluation value from among one or more candidate motion vectors as the best candidate motion vector.

Then, the inter-screen prediction unit 126 derives a motion vector of the processing target region by searching around the best candidate motion vector (S203).

That is, the inter-screen prediction unit 126 similarly calculates an evaluation value for a motion vector indicating a region around the region indicated by the best candidate motion vector. Then, when there is a motion vector having an evaluation value better than the best candidate motion vector, the inter-screen prediction unit 126 updates the best candidate motion vector with a motion vector having an evaluation value better than the best candidate motion vector. Then, the inter-screen prediction unit 126 derives the updated best candidate motion vector as the final motion vector of the processing target region.

Note that the inter-screen prediction unit 126 may derive the best candidate motion vector as the final motion vector of the processing target region without performing the process of searching around the best candidate motion vector (S203). The best candidate motion vector is not limited to the candidate motion vector having the best evaluation value. One of one or more candidate motion vectors having an evaluation value equal to or higher than a reference may be selected as the best candidate motion vector according to a predetermined priority.

Also, here, the process related to the processing target area and the processed area is, for example, an encoding or decoding process. More specifically, the process related to the processing target area and the processed area may be a process for deriving a motion vector. Alternatively, the process related to the processing target area and the processed area may be a reconstruction process.

[Example of encoding device implementation]
FIG. 22 is a block diagram illustrating an implementation example of the encoding apparatus 100 according to Embodiment 1. The encoding device 100 includes a circuit 160 and a memory 162. For example, a plurality of components of the encoding device 100 shown in FIGS. 1 and 11 are implemented by the circuit 160 and the memory 162 shown in FIG.

The circuit 160 is a circuit that performs information processing and is a circuit that can access the memory 162. For example, the circuit 160 is a dedicated or general-purpose electronic circuit that encodes a moving image. The circuit 160 may be a processor such as a CPU. The circuit 160 may be an aggregate of a plurality of electronic circuits. Further, for example, the circuit 160 may serve as a plurality of constituent elements excluding a constituent element for storing information among a plurality of constituent elements of the encoding device 100 illustrated in FIG. 1 and the like.

The memory 162 is a dedicated or general-purpose memory in which information for the circuit 160 to encode a moving image is stored. The memory 162 may be an electronic circuit or may be connected to the circuit 160. In addition, the memory 162 may be included in the circuit 160. The memory 162 may be an aggregate of a plurality of electronic circuits. Further, the memory 162 may be a magnetic disk or an optical disk, or may be expressed as a storage or a recording medium. The memory 162 may be a non-volatile memory or a volatile memory.

For example, in the memory 162, a moving image to be encoded may be stored, or a bit string corresponding to the encoded moving image may be stored. The memory 162 may store a program for the circuit 160 to encode a moving image.

For example, the memory 162 may serve as a component for storing information among a plurality of components of the encoding device 100 illustrated in FIG. Specifically, the memory 162 may serve as the block memory 118 and the frame memory 122 shown in FIG. More specifically, the memory 162 may store a reconstructed block, a reconstructed picture, and the like.

Note that in the encoding device 100, not all of the plurality of components shown in FIG. 1 or the like may be mounted, or all of the plurality of processes described above may not be performed. Some of the plurality of components shown in FIG. 1 and the like may be included in another device, and some of the plurality of processes described above may be executed by another device. In the encoding device 100, some of the plurality of components shown in FIG. 1 and the like are mounted, and a part of the plurality of processes described above is performed, so that motion compensation is efficiently performed. Is called.

Hereinafter, a plurality of operation examples of the encoding apparatus 100 shown in FIG. 22 will be shown. In a plurality of operation examples below, the template FRUC method uses a motion vector of a processing target region that is a block or a sub-block as a reconstructed image of a region adjacent to the processing target region and a reconstructed image of a region in a reference picture. This is a method of deriving according to the degree of matching. In addition, the bilateral FRUC method is a method for deriving the motion vector of the processing target region according to the degree of matching between the two reconstructed images of the two regions in two different reference pictures.

In addition, the normal inter-screen prediction method is a method for deriving a motion vector of a processing target region and encoding information on the motion vector of the processing target region. That is, when the circuit 160 derives the motion vector of the processing target area using the normal inter-screen prediction method, the circuit 160 encodes the information on the motion vector of the processing target area.

FIG. 23 is a flowchart showing a first operation example of the encoding apparatus 100 shown in FIG. For example, the encoding apparatus 100 illustrated in FIG. 22 performs the operation illustrated in FIG. 23 when performing motion compensation and encoding a moving image.

Specifically, the circuit 160 of the encoding device 100 derives a motion vector of an image block in a moving image (S311). Then, the circuit 160 performs motion compensation in units of blocks or sub-blocks constituting the blocks (S312).

For example, the circuit 160 derives the motion vector of the sub block by the bilateral FRUC method when the motion vector of the block is derived by the template FRUC method and the motion compensation is performed in units of the sub block. Then, the circuit 160 performs motion compensation in units of sub-blocks using the sub-block motion vectors.

Thereby, the encoding apparatus 100 can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, encoding apparatus 100 can appropriately derive a motion vector of a sub block even when a reconstructed image of a region adjacent to the sub block is not generated. Then, the encoding apparatus 100 can efficiently perform motion compensation using a motion vector that is appropriately derived.

Further, for example, in the case where the motion compensation is performed by deriving the motion vector of the block by the template FRUC method, the circuit 160 performs the motion compensation in units of the block when the motion vector of the block is a unidirectional prediction motion vector. May be. In this case, the circuit 160 may perform motion compensation in units of blocks using the motion vectors of the blocks.

The circuit 160 performs motion compensation in units of sub-blocks when the motion vector of the block is a bidirectional motion vector when the motion vector of the block is derived by the template FRUC method and motion compensation is performed. Also good. In this case, the circuit 160 may perform motion compensation in units of sub-blocks using the sub-block motion vectors.

Accordingly, the encoding apparatus 100 can derive the sub-block motion vector by the bilateral FRUC method when the motion vector derived as the block motion vector by the template FRUC method is suitable for the bilateral FRUC method. it can. Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector derived as the block motion vector in the template FRUC method is not suitable for the bilateral FRUC method, the encoding apparatus 100 efficiently uses the block motion vector as it is and performs motion compensation in units of blocks. It can be performed.

Further, for example, when the block 160 derives a block motion vector by the bilateral FRUC method and performs motion compensation in units of subblocks, the circuit 160 may derive the subblock motion vector by the bilateral FRUC method. The circuit 160 may perform motion compensation in units of sub-blocks using the sub-block motion vectors.

Accordingly, the encoding apparatus 100 derives a sub-block motion vector using the bilateral FRUC method, regardless of whether a block motion vector is derived using the template FRUC method or a block motion vector using the bilateral FRUC method. can do. Therefore, encoding apparatus 100 can derive the motion vector of the sub-block in the same way in these two cases.

Further, for example, when deriving a sub-block motion vector, the circuit 160 derives a sub-block motion vector candidate using the block motion vector, and derives a sub-block motion vector using the derived candidate. May be. Thereby, the encoding apparatus 100 can derive the motion vector of the sub-block using the motion vector of the block. Therefore, the encoding apparatus 100 can improve prediction accuracy.

FIG. 24 is a flowchart showing a second operation example of the encoding apparatus 100 shown in FIG. For example, the encoding apparatus 100 illustrated in FIG. 22 performs the operation illustrated in FIG. 24 when performing motion compensation and encoding a moving image.

Specifically, the circuit 160 of the encoding device 100 encodes first control information indicating one method for deriving a motion vector of an image block in a moving image (S321). Then, the circuit 160 encodes second control information indicating whether it is effective or ineffective to perform motion compensation in units of sub-blocks constituting the block (S322).

Then, the circuit 160 derives the motion vector of the block by one method (S323). Then, the circuit 160 determines whether to perform motion compensation in units of subblocks or motion compensation in units of blocks according to whether motion compensation in units of subblocks is valid or invalid ( S324).

Here, when it is determined that motion compensation is performed in units of sub-blocks (Yes in S324), the circuit 160 derives a motion vector of the sub-blocks (S325). Then, the circuit 160 performs motion compensation in units of sub-blocks using the sub-block motion vectors (S326). On the other hand, when it is determined that motion compensation is performed in units of blocks (No in S324), the circuit 160 performs motion compensation in units of blocks using the motion vectors of the blocks (S327).

Thereby, the encoding apparatus 100 can enable or disable the motion compensation in units of sub-blocks separately from the method of deriving the block motion vector. Therefore, the encoding apparatus 100 can appropriately suppress that the motion compensation is performed inefficiently. That is, the encoding apparatus 100 can efficiently perform motion compensation.

For example, the circuit 160 may select one method for deriving a block motion vector from a plurality of methods including a normal inter-screen prediction method, a template FRUC method, and a bilateral FRUC method. Thereby, the encoding apparatus 100 can adaptively select one method for deriving a motion vector of a block from a plurality of methods.

In addition, for example, when one scheme for deriving a motion vector of a block is the template FRUC scheme or the bilateral FRUC scheme, the circuit 160 determines that the motion compensation is performed in units of subblocks. Motion compensation may be performed in units. Then, when one scheme for deriving the motion vector of the block is the template FRUC scheme or the bilateral FRUC scheme, the circuit 160 performs motion compensation in block units when it is determined to perform motion compensation in block units. May be performed.

As a result, when the motion vector of the block is derived by the FRUC method, the encoding apparatus 100 can perform the motion compensation in an appropriate unit according to the determination result of whether to perform the motion compensation in the subblock unit. it can. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks. Therefore, the encoding apparatus 100 performs motion compensation in an appropriate unit according to whether it is effective to perform motion compensation in units of sub-blocks when a block motion vector is derived by the FRUC method. Can do.

In addition, for example, the circuit 160 performs motion in units of subblocks when it is determined that motion compensation is performed in units of subblocks when one method for deriving a motion vector of a block is a normal inter-screen prediction method. Compensation may be performed. The circuit 160 performs motion compensation in units of blocks when it is determined that motion compensation is performed in units of blocks when one method for deriving a motion vector of a block is a normal inter-screen prediction method. Also good.

Thereby, when the motion vector of a block is derived by a normal inter-screen prediction method different from the FRUC method, the encoding apparatus 100 can appropriately perform the determination according to the determination result of whether or not to perform motion compensation in units of subblocks. Motion compensation can be performed in units. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks.

Therefore, the encoding apparatus 100 performs motion compensation in appropriate units according to whether or not it is effective to perform motion compensation in units of sub-blocks when a motion vector of a block is derived by the normal inter-frame prediction method. It can be performed.

Also, for example, when the sub-block motion vector is derived, the circuit 160 may derive the sub-block motion vector using the bilateral FRUC method. Thereby, the encoding apparatus 100 can appropriately derive the motion vector of the sub-block even when the reconstructed image of the region adjacent to the sub-block is not generated. Therefore, the encoding apparatus 100 can efficiently perform motion compensation using an appropriately derived motion vector.

For example, the circuit 160 determines that the motion compensation is performed in units of sub-blocks when the motion vector of the block is a motion vector for bidirectional prediction and it is effective to perform motion compensation in units of sub-blocks. May be. The circuit 160 may determine that the motion compensation is performed in units of blocks when the motion vector of the block is a motion vector for bidirectional prediction and it is invalid to perform motion compensation in units of sub-blocks. .

The circuit 160 may determine that the motion compensation is performed in units of blocks when the motion vector of the block is a unidirectional motion vector.

As a result, the encoding apparatus 100 converts the sub-block motion vector into the bilateral when the block motion vector is suitable for the bilateral FRUC scheme and it is effective to perform motion compensation in units of sub-blocks. It can be derived by the FRUC method. Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector of a block is not suitable for the bilateral FRUC method or when it is invalid to perform motion compensation in units of sub-blocks, the encoding apparatus 100 can efficiently use the motion vector of the block as it is. In addition, motion compensation can be performed in units of blocks.

Further, for example, when it is effective to perform motion compensation in units of subblocks, the circuit 160 determines that motion compensation is performed in units of subblocks, and it is invalid to perform motion compensation in units of subblocks. In some cases, it may be determined that motion compensation is performed in units of blocks.

Thereby, the encoding apparatus 100 can perform motion compensation in units of sub-blocks when it is effective to perform motion compensation in units of sub-blocks. Then, when it is invalid to perform motion compensation in units of subblocks, the encoding apparatus 100 can perform motion compensation in units of blocks. Therefore, the encoding apparatus 100 can simply control a unit in which motion compensation is performed.

Also, for example, the circuit 160 may encode the first control information into the header layer of the block, the header layer of the slice including the block, the header layer of the picture including the block, or the header layer of the stream including the block. The circuit 160 may encode the second control information into the header layer of the block, the header layer of the slice, the header layer of the picture, or the header layer of the stream.

Thereby, the encoding apparatus 100 can designate a scheme for deriving a motion vector of a block and whether or not it is effective to perform motion compensation in units of sub-blocks within an appropriate range.

Also, for example, the first control information is FRUC control information as described above, and the second control information is subblock processing control information as described above.

In the above example, the circuit 160 encodes both the first control information and the second control information. However, the circuit 160 may encode only the first control information out of the first control information and the second control information, and may not encode the second control information. In particular, for example, when it is determined that the motion compensation is performed in units of blocks regardless of whether the motion compensation is performed in units of sub-blocks, the circuit 160 determines the second control information. It may not be encoded.

More specifically, for example, as shown in FIGS. 15 and 16, when the motion vector of a block is derived by the normal inter-screen prediction method, it is uniformly decided to perform motion compensation in units of blocks. In this case, the second control information may not be encoded. Also, for example, as shown in FIG. 16, when the motion vector of a block is a unidirectional prediction motion vector, the second control information is determined when it is uniformly determined to perform motion compensation in units of blocks. May not be encoded.

Further, as illustrated in FIGS. 13 and 14, for example, the circuit 160 may not encode the second control information when the second control information is not used. In addition, when a method for deriving a motion vector of a block is determined in advance, the circuit 160 may not encode the first control information.

[Decoding device implementation example]
FIG. 25 is a block diagram illustrating an implementation example of the decoding device 200 according to the first embodiment. The decoding device 200 includes a circuit 260 and a memory 262. For example, a plurality of components of the decoding device 200 shown in FIGS. 10 and 12 are implemented by the circuit 260 and the memory 262 shown in FIG.

The circuit 260 is a circuit that performs information processing and is a circuit that can access the memory 262. For example, the circuit 260 is a dedicated or general-purpose electronic circuit that decodes a moving image. The circuit 260 may be a processor such as a CPU. The circuit 260 may be an aggregate of a plurality of electronic circuits. Further, for example, the circuit 260 may serve as a plurality of constituent elements excluding the constituent elements for storing information among the plurality of constituent elements of the decoding device 200 illustrated in FIG. 10 and the like.

The memory 262 is a dedicated or general-purpose memory in which information for the circuit 260 to decode a moving image is stored. The memory 262 may be an electronic circuit or may be connected to the circuit 260. Further, the memory 262 may be included in the circuit 260. The memory 262 may be an aggregate of a plurality of electronic circuits. The memory 262 may be a magnetic disk or an optical disk, or may be expressed as a storage or a recording medium. Further, the memory 262 may be a nonvolatile memory or a volatile memory.

For example, the memory 262 may store a bit sequence corresponding to the encoded moving image, or may store a moving image corresponding to the decoded bit sequence. The memory 262 may store a program for the circuit 260 to decode a moving image.

For example, the memory 262 may serve as a component for storing information among a plurality of components of the decoding device 200 illustrated in FIG. 10 and the like. Specifically, the memory 262 may serve as the block memory 210 and the frame memory 214 shown in FIG. More specifically, the memory 262 may store a reconstructed block, a reconstructed picture, and the like.

Note that in the decoding device 200, not all of the plurality of components shown in FIG. 10 and the like may be implemented, or all of the plurality of processes described above may not be performed. Some of the plurality of components shown in FIG. 10 and the like may be included in another device, and some of the plurality of processes described above may be executed by another device. Then, in the decoding device 200, some of the plurality of components shown in FIG. 10 and the like are mounted, and motion compensation is efficiently performed by performing some of the plurality of processes described above. .

Hereinafter, a plurality of operation examples of the decoding device 200 shown in FIG. 25 will be shown. In a plurality of operation examples below, the template FRUC method uses a motion vector of a processing target region that is a block or a sub-block as a reconstructed image of a region adjacent to the processing target region and a reconstructed image of a region in a reference picture. This is a method of deriving according to the degree of matching. In addition, the bilateral FRUC method is a method for deriving the motion vector of the processing target region according to the degree of matching between the two reconstructed images of the two regions in two different reference pictures.

In addition, the normal inter-screen prediction method is a method of decoding the motion vector information of the processing target area and deriving the motion vector of the processing target area. That is, when the circuit 260 derives the motion vector of the processing target region using the normal inter-screen prediction method, the circuit 260 decodes the information on the motion vector of the processing target region.

FIG. 26 is a flowchart showing a first operation example of the decoding device 200 shown in FIG. For example, the decoding device 200 illustrated in FIG. 25 performs the operation illustrated in FIG. 26 when performing motion compensation and decoding a moving image.

Specifically, the circuit 260 of the decoding device 200 derives a motion vector of an image block in a moving image (S411). Then, the circuit 260 performs motion compensation in units of blocks or sub-blocks constituting the blocks (S412).

For example, the circuit 260 derives the motion vector of the sub block by the bilateral FRUC method when the motion vector of the block is derived by the template FRUC method and the motion compensation is performed in units of the sub block. Then, the circuit 260 performs motion compensation in units of sub-blocks using the sub-block motion vectors.

Thereby, the decoding apparatus 200 can derive the sub-block motion vector by the bilateral FRUC method even when the block motion vector is derived by the template FRUC method. Therefore, the decoding apparatus 200 can appropriately derive the motion vector of the sub block even when the reconstructed image of the region adjacent to the sub block is not generated. Then, the decoding apparatus 200 can efficiently perform motion compensation using the appropriately derived motion vector.

Also, for example, when the block 260 derives a motion vector of a block by the template FRUC method and performs motion compensation, if the motion vector of the block is a unidirectional motion vector, the circuit 260 performs motion compensation in units of blocks. May be. In this case, the circuit 260 may perform motion compensation in units of blocks using the motion vectors of the blocks.

The circuit 260 performs motion compensation in units of sub-blocks when the motion vector of the block is a bidirectional motion vector when the motion vector of the block is derived by the template FRUC method and motion compensation is performed. Also good. In this case, the circuit 260 may perform motion compensation in units of sub-blocks using the sub-block motion vectors.

Accordingly, the decoding apparatus 200 can derive the sub-block motion vector by the bilateral FRUC method when the motion vector derived as the block motion vector by the template FRUC method is suitable for the bilateral FRUC method. . Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when a motion vector derived as a block motion vector in the template FRUC method is not suitable for the bilateral FRUC method, the decoding apparatus 200 efficiently performs motion compensation in units of blocks using the block motion vector as it is. It can be carried out.

Further, for example, when the block 260 derives a block motion vector by the bilateral FRUC method and performs motion compensation in units of subblocks, the circuit 260 may derive the subblock motion vector by the bilateral FRUC method. The circuit 260 may perform motion compensation in units of sub-blocks using the sub-block motion vectors.

Accordingly, the decoding apparatus 200 derives a sub-block motion vector using the bilateral FRUC method, regardless of whether a block motion vector is derived using the template FRUC method or a block motion vector using the bilateral FRUC method. be able to. Therefore, the decoding apparatus 200 can derive the motion vector of the sub-block in the same way in these two cases.

Further, for example, when deriving a sub-block motion vector, the circuit 260 derives a sub-block motion vector candidate using the block motion vector, and derives a sub-block motion vector using the derived candidate. May be. Thereby, the decoding apparatus 200 can derive the motion vector of the sub-block using the motion vector of the block. Therefore, the decoding apparatus 200 can improve prediction accuracy.

FIG. 27 is a flowchart showing a second operation example of the decoding device 200 shown in FIG. For example, the decoding device 200 illustrated in FIG. 25 performs the operation illustrated in FIG. 27 when performing motion compensation and decoding a moving image.

Specifically, the circuit 260 of the decoding device 200 decodes first control information indicating one method for deriving a motion vector of an image block in a moving image (S421). Then, the circuit 260 decodes the second control information indicating whether it is valid or invalid to perform motion compensation in units of sub-blocks constituting the block (S422).

Then, the circuit 260 derives the motion vector of the block by one method (S423). Then, the circuit 260 determines whether to perform motion compensation in units of sub-blocks or motion compensation in units of blocks according to whether motion compensation in units of sub-blocks is valid or invalid ( S424).

Here, when it is determined that motion compensation is performed in units of sub-blocks (Yes in S424), the circuit 260 derives a motion vector of the sub-blocks (S425). Then, the circuit 260 performs motion compensation in units of sub-blocks using the sub-block motion vectors (S426). On the other hand, when it is determined that motion compensation is to be performed in units of blocks (No in S424), the circuit 260 performs motion compensation in units of blocks using the motion vectors of the blocks (S427).

Thereby, the decoding apparatus 200 can enable or disable the motion compensation in units of sub-blocks separately from the method of deriving the block motion vector. Therefore, the decoding apparatus 200 can appropriately suppress that the motion compensation is performed inefficiently. That is, the decoding device 200 can efficiently perform motion compensation.

For example, the circuit 260 may select one method for deriving a block motion vector from a plurality of methods including a normal inter-screen prediction method, a template FRUC method, and a bilateral FRUC method. Thereby, the decoding apparatus 200 can adaptively select one method for deriving a motion vector of a block from a plurality of methods.

In addition, for example, when one method for deriving a motion vector of a block is the template FRUC method or the bilateral FRUC method, the circuit 260 determines that the motion compensation is performed in units of subblocks. Motion compensation may be performed in units. Then, when one method for deriving the motion vector of the block is the template FRUC method or the bilateral FRUC method, the circuit 260 performs motion compensation in block units when it is determined to perform motion compensation in block units. May be performed.

Thereby, when the motion vector of a block is derived by the FRUC method, the decoding apparatus 200 can perform motion compensation in an appropriate unit according to a determination result of whether or not motion compensation is performed in units of subblocks. . The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks. Therefore, when the motion vector of a block is derived by the FRUC method, the decoding apparatus 200 can perform motion compensation in an appropriate unit according to whether or not it is effective to perform motion compensation in a sub-block unit. it can.

Further, for example, when one method for deriving a motion vector of a block is a normal inter-screen prediction method, the circuit 260 performs motion in units of subblocks when it is determined that motion compensation is performed in units of subblocks. Compensation may be performed. The circuit 260 performs motion compensation in units of blocks when it is determined that motion compensation is performed in units of blocks when one method for deriving a motion vector of the block is a normal inter-screen prediction method. Also good.

Thereby, when the motion vector of a block is derived by a normal inter-screen prediction method different from the FRUC method, the decoding apparatus 200 can select an appropriate unit according to the determination result of whether to perform motion compensation in units of subblocks. Motion compensation can be performed. The determination result depends on whether or not it is effective to perform motion compensation in units of sub-blocks.

Therefore, the decoding apparatus 200 performs motion compensation in an appropriate unit according to whether it is effective to perform motion compensation in units of sub-blocks when a motion vector of a block is derived by the normal inter-frame prediction method. It can be carried out.

Also, for example, when the sub-block motion vector is derived, the circuit 260 may derive the sub-block motion vector by the bilateral FRUC method. Thereby, the decoding apparatus 200 can appropriately derive the motion vector of the sub-block even when the reconstructed image of the area adjacent to the sub-block is not generated. Therefore, the decoding apparatus 200 can efficiently perform motion compensation using the appropriately derived motion vector.

For example, the circuit 260 determines that the motion compensation is performed in units of sub-blocks when the motion vector of the block is a bidirectional motion vector and it is effective to perform motion compensation in units of sub-blocks. May be. The circuit 260 may determine that the motion compensation is performed in units of blocks when the motion vector of the block is a motion vector for bidirectional prediction and it is invalid to perform motion compensation in units of sub-blocks. .

The circuit 260 may determine that the motion compensation is performed in units of blocks when the motion vector of the block is a unidirectional motion vector.

As a result, the decoding apparatus 200 converts the sub-block motion vector to the bilateral FRUC when the motion vector of the block is suitable for the bilateral FRUC scheme and it is effective to perform motion compensation in units of sub-blocks. Can be derived in a manner. Therefore, for example, when the motion vector of the sub-block is derived using the motion vector of the block, an appropriate motion vector can be used.

On the other hand, when the motion vector of the block is not suitable for the bilateral FRUC method or when it is invalid to perform motion compensation in units of sub-blocks, the decoding apparatus 200 efficiently uses the motion vector of the block as it is. Motion compensation can be performed in units of blocks.

Further, for example, when it is effective to perform motion compensation in units of sub-blocks, the circuit 260 determines that motion compensation is performed in units of sub-blocks, and it is invalid to perform motion compensation in units of sub-blocks. In some cases, it may be determined that motion compensation is performed in units of blocks.

Thereby, the decoding apparatus 200 can perform motion compensation in units of sub-blocks when it is effective to perform motion compensation in units of sub-blocks. The decoding apparatus 200 can perform motion compensation in units of blocks when it is invalid to perform motion compensation in units of sub-blocks. Therefore, the decoding apparatus 200 can simply control the unit in which motion compensation is performed.

Also, for example, the circuit 260 may decode the first control information from the header layer of the block, the header layer of the slice including the block, the header layer of the picture including the block, or the header layer of the stream including the block. The circuit 260 may decode the second control information from the header layer of the block, the header layer of the slice, the header layer of the picture, or the header layer of the stream.

Thereby, the decoding apparatus 200 can specify a scheme for deriving a motion vector of a block and whether or not it is effective to perform motion compensation in units of sub-blocks within an appropriate range.

In the above example, the circuit 260 decodes both the first control information and the second control information. However, the circuit 260 may decode only the first control information out of the first control information and the second control information, and may not decode the second control information. In particular, for example, when it is determined that the motion compensation is performed in units of blocks regardless of whether the motion compensation is performed in units of sub-blocks, the circuit 260 determines the second control information. Decoding is not necessary.

More specifically, for example, as shown in FIGS. 15 and 16, when the motion vector of a block is derived by the normal inter-screen prediction method, it is uniformly decided to perform motion compensation in units of blocks. In this case, the second control information may not be decoded. Also, for example, as shown in FIG. 16, when the motion vector of a block is a unidirectional prediction motion vector, the second control information is determined when it is uniformly determined to perform motion compensation in units of blocks. May not be decrypted.

In addition, as illustrated in FIGS. 13 and 14, for example, the circuit 260 may not decode the second control information when the second control information is not used. In addition, when a method for deriving a motion vector of a block is determined in advance, the circuit 260 may not decode the first control information.

[Supplement]
Also, the encoding device 100 and the decoding device 200 in the present embodiment may be used as an image encoding device and an image decoding device, respectively, or may be used as a moving image encoding device and a moving image decoding device, respectively. Good. Alternatively, the encoding device 100 and the decoding device 200 can each be used as an inter prediction device (inter-screen prediction device).

That is, the encoding device 100 and the decoding device 200 may correspond to only the inter prediction unit (inter-screen prediction unit) 126 and the inter prediction unit (inter-screen prediction unit) 218, respectively. Other components such as the conversion unit 106 and the inverse conversion unit 206 may be included in other devices.

In the present embodiment, each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

Specifically, each of the encoding device 100 and the decoding device 200 includes a processing circuit (Processing Circuit) and a storage device (Storage) electrically connected to the processing circuit and accessible from the processing circuit. You may have. For example, the processing circuit corresponds to the

circuit

160 or 260, and the storage device corresponds to the

memory

162 or 262.

The processing circuit includes at least one of dedicated hardware and a program execution unit, and executes processing using a storage device. Further, when the processing circuit includes a program execution unit, the storage device stores a software program executed by the program execution unit.

Here, the software that realizes the encoding apparatus 100 or the decoding apparatus 200 of the present embodiment is the following program.

That is, this program is an encoding method for encoding a moving image by performing motion compensation on a computer, and derives a motion vector of an image block in the moving image, and the unit of the block or the block In the case where the motion compensation is performed in units of sub-blocks constituting the block, the motion vector of the block is derived by a template FRUC (Frame Rate Up-Conversion) method, and the motion compensation is performed in units of the sub-blocks. A motion vector of the sub-block is derived by a lateral FRUC method, the motion compensation is performed in units of the sub-block using the motion vector of the sub-block, and the template FRUC method is a process that is the block or the sub-block. The motion vector of the target area The method is derived according to the degree of matching between the reconstructed image of the region adjacent to the processing target region and the reconstructed image of the region in the reference picture. The bilateral FRUC method uses different motion vectors of the processing target region. An encoding method that is a method of deriving according to the degree of matching between two reconstructed images of two regions in two reference pictures may be executed.

Alternatively, this program is a decoding method for decoding a moving image by performing motion compensation on a computer, and deriving a motion vector of an image block in the moving image, and configuring the unit of the block or the block In the case where the motion compensation is performed in units of sub-blocks, the motion vector of the block is derived by a template FRUC (Frame Rate Up-Conversion) method, and the motion compensation is performed in units of the sub-blocks, bilateral FRUC A motion vector of the sub-block is derived by a method, the motion compensation is performed in units of the sub-block using the motion vector of the sub-block, and the template FRUC method is a processing target region that is the block or the sub-block. The motion vector of This is a method of deriving according to the degree of matching between the reconstructed image of the region adjacent to the target region and the reconstructed image of the region in the reference picture. The bilateral FRUC method uses two different motion vectors for the processing target region. A decoding method that is a method of deriving according to the degree of matching between two reconstructed images of two regions in two reference pictures may be executed.

Alternatively, this program is an encoding method for encoding a moving image by performing motion compensation on a computer, and includes first control information indicating one method for deriving a motion vector of an image block in the moving image. Encode, encode second control information indicating whether it is effective or ineffective to perform the motion compensation in units of sub-blocks constituting the block, and derive a motion vector of the block by the one method And determining whether to perform the motion compensation in units of the sub-blocks or to perform the motion compensation in units of the blocks according to whether the motion compensation in units of the sub-block is valid or invalid If it is determined that the motion compensation is performed in units of the sub-block, a motion vector of the sub-block is derived and the motion of the sub-block is derived. When it is determined that the motion compensation is performed in units of the sub-blocks using a Kuttle, and the motion compensation is performed in units of the blocks, the motion compensation is performed in units of the blocks using a motion vector of the blocks. An encoding method may be executed.

Alternatively, this program is a decoding method for decoding a moving image by performing motion compensation on a computer, and decoding first control information indicating one method for deriving a motion vector of an image block in the moving image. , Decoding second control information indicating whether the motion compensation is valid or invalid in units of sub-blocks constituting the block, and deriving a motion vector of the block by the one method, Determining whether to perform the motion compensation in units of the sub-blocks or whether to perform the motion compensation in units of the blocks according to whether the motion compensation in units of the sub-block is valid or invalid. When it is determined that the motion compensation is performed in units of the sub-block, a motion vector of the sub-block is derived, and the motion vector of the sub-block is derived A decoding method for performing motion compensation in units of sub-blocks and performing motion compensation in units of blocks using a motion vector of the blocks when it is determined to perform motion compensation in units of blocks May be executed.

Each component may be a circuit as described above. These circuits may constitute one circuit as a whole, or may be separate circuits. Each component may be realized by a general-purpose processor or a dedicated processor.

Also, another component may execute the process executed by a specific component. In addition, the order in which the processes are executed may be changed, or a plurality of processes may be executed in parallel. Further, the encoding / decoding device may include the encoding device 100 and the decoding device 200.

The first and second ordinal numbers used in the description may be replaced as appropriate. In addition, an ordinal number may be newly given to a component or the like, or may be removed.

As mentioned above, although the aspect of the encoding apparatus 100 and the decoding apparatus 200 was demonstrated based on embodiment, the aspect of the encoding apparatus 100 and decoding apparatus 200 is not limited to this embodiment. As long as it does not deviate from the gist of the present disclosure, the encoding device 100 and the decoding device 200 may be configured in which various modifications conceived by those skilled in the art have been made in the present embodiment, or in a form constructed by combining components in different embodiments. It may be included within the scope of the embodiment.

This aspect may be implemented in combination with at least a part of other aspects in the present disclosure. In addition, a part of the processing, a part of the configuration of the apparatus, a part of the syntax, and the like described in the flowchart of this aspect may be combined with another aspect.

(Embodiment 2)
In each of the above embodiments, each of the functional blocks can usually be realized by an MPU, a memory, and the like. Further, the processing by each functional block is usually realized by a program execution unit such as a processor reading and executing software (program) recorded on a recording medium such as a ROM. The software may be distributed by downloading or the like, or may be distributed by being recorded on a recording medium such as a semiconductor memory. Naturally, each functional block can be realized by hardware (dedicated circuit).

Further, the processing described in each embodiment may be realized by centralized processing using a single device (system), or may be realized by distributed processing using a plurality of devices. Good. The number of processors that execute the program may be one or more. That is, centralized processing may be performed, or distributed processing may be performed.

The aspects of the present disclosure are not limited to the above embodiments, and various modifications are possible, and these are also included within the scope of the aspects of the present disclosure.

Furthermore, application examples of the moving picture coding method (picture coding method) or the moving picture decoding method (picture decoding method) shown in the above embodiments and a system using the same will be described. The system includes an image encoding device using an image encoding method, an image decoding device using an image decoding method, and an image encoding / decoding device including both. Other configurations in the system can be appropriately changed according to circumstances.

[Example of use]
FIG. 28 is a diagram showing an overall configuration of a content supply system ex100 that implements a content distribution service. The communication service providing area is divided into desired sizes, and base stations ex106, ex107, ex108, ex109, and ex110, which are fixed wireless stations, are installed in each cell.

In the content supply system ex100, devices such as a computer ex111, a game machine ex112, a camera ex113, a home appliance ex114, and a smartphone ex115 via the Internet ex101, the Internet service provider ex102 or the communication network ex104, and the base stations ex106 to ex110. Is connected. The content supply system ex100 may be connected by combining any of the above elements. Each device may be directly or indirectly connected to each other via a telephone network or a short-range wireless communication without using the base stations ex106 to ex110 which are fixed wireless stations. The streaming server ex103 is connected to each device such as a computer ex111, a game machine ex112, a camera ex113, a home appliance ex114, and a smartphone ex115 via the Internet ex101. The streaming server ex103 is connected to a terminal in a hot spot in the airplane ex117 via the satellite ex116.

Note that a wireless access point or a hot spot may be used instead of the base stations ex106 to ex110. Further, the streaming server ex103 may be directly connected to the communication network ex104 without going through the Internet ex101 or the Internet service provider ex102, or may be directly connected to the airplane ex117 without going through the satellite ex116.

The camera ex113 is a device that can shoot still images and moving images such as a digital camera. The smartphone ex115 is a smartphone, a cellular phone, or a PHS (Personal Handyphone System) that is compatible with a mobile communication system generally called 2G, 3G, 3.9G, 4G, and 5G in the future.

The home appliance ex118 is a device included in a refrigerator or a household fuel cell cogeneration system.

In the content supply system ex100, a terminal having a photographing function is connected to the streaming server ex103 through the base station ex106 or the like, thereby enabling live distribution or the like. In live distribution, the terminal (computer ex111, game machine ex112, camera ex113, home appliance ex114, smartphone ex115, terminal in airplane ex117, etc.) is used for the still image or video content captured by the user using the terminal. The encoding process described in each embodiment is performed, and the video data obtained by the encoding and the sound data obtained by encoding the sound corresponding to the video are multiplexed, and the obtained data is transmitted to the streaming server ex103. That is, each terminal functions as an image encoding device according to an aspect of the present disclosure.

On the other hand, the streaming server ex103 streams the content data transmitted to the requested client. The client is a computer or the like in the computer ex111, the game machine ex112, the camera ex113, the home appliance ex114, the smart phone ex115, or the airplane ex117 that can decode the encoded data. Each device that has received the distributed data decrypts and reproduces the received data. That is, each device functions as an image decoding device according to an aspect of the present disclosure.

[Distributed processing]
The streaming server ex103 may be a plurality of servers or a plurality of computers, and may process, record, and distribute data in a distributed manner. For example, the streaming server ex103 may be realized by a CDN (Contents Delivery Network), and content distribution may be realized by a network connecting a large number of edge servers and edge servers distributed all over the world. In CDN, edge servers that are physically close to each other are dynamically allocated according to clients. Then, the content can be cached and distributed to the edge server, thereby reducing the delay. Also, if some error occurs or the communication status changes due to an increase in traffic, etc., the processing is distributed among multiple edge servers, the distribution subject is switched to another edge server, or the part of the network where the failure has occurred Since detouring can be continued, high-speed and stable distribution can be realized.

In addition to the distributed processing of the distribution itself, the captured data may be encoded at each terminal, may be performed on the server side, or may be shared with each other. As an example, in general, in an encoding process, a processing loop is performed twice. In the first loop, the complexity of the image or the code amount in units of frames or scenes is detected. In the second loop, processing for maintaining the image quality and improving the coding efficiency is performed. For example, the terminal performs the first encoding process, and the server receiving the content performs the second encoding process, thereby improving the quality and efficiency of the content while reducing the processing load on each terminal. it can. In this case, if there is a request to receive and decode in almost real time, the encoded data of the first time performed by the terminal can be received and reproduced by another terminal, enabling more flexible real-time distribution. Become.

As another example, the camera ex113 or the like extracts a feature amount from an image, compresses data relating to the feature amount as metadata, and transmits the metadata to the server. The server performs compression according to the meaning of the image, for example, by determining the importance of the object from the feature amount and switching the quantization accuracy. The feature data is particularly effective for improving the accuracy and efficiency of motion vector prediction at the time of re-compression on the server. Also, simple coding such as VLC (variable length coding) may be performed at the terminal, and coding with a large processing load such as CABAC (context adaptive binary arithmetic coding) may be performed at the server.

As yet another example, in a stadium, a shopping mall, a factory, or the like, there may be a plurality of video data in which almost the same scene is captured by a plurality of terminals. In this case, for example, a GOP (Group of Picture) unit, a picture unit, or a tile obtained by dividing a picture using a plurality of terminals that have performed shooting and other terminals and servers that have not performed shooting as necessary. Distributed processing is performed by assigning encoding processing in units or the like. Thereby, delay can be reduced and real-time property can be realized.

In addition, since the plurality of video data are almost the same scene, the server may manage and / or instruct the video data captured by each terminal to refer to each other. Alternatively, the encoded data from each terminal may be received by the server and the reference relationship may be changed among a plurality of data, or the picture itself may be corrected or replaced to be encoded again. This makes it possible to generate a stream with improved quality and efficiency of each piece of data.

Also, the server may distribute the video data after performing transcoding to change the encoding method of the video data. For example, the server may convert the MPEG encoding system to the VP encoding. 264. It may be converted into H.265.

Thus, the encoding process can be performed by a terminal or one or more servers. Therefore, in the following, description such as “server” or “terminal” is used as the subject performing processing, but part or all of processing performed by the server may be performed by the terminal, or processing performed by the terminal may be performed. Some or all may be performed at the server. The same applies to the decoding process.

[3D, multi-angle]
In recent years, different scenes photographed by terminals such as a plurality of cameras ex113 and / or smartphones ex115 that are substantially synchronized with each other, or images or videos obtained by photographing the same scene from different angles have been increasingly used. Yes. The video captured by each terminal is integrated based on the relative positional relationship between the terminals acquired separately or the region where the feature points included in the video match.

The server not only encodes a two-dimensional moving image, but also encodes a still image automatically based on a scene analysis of the moving image or at a time specified by the user and transmits it to the receiving terminal. Also good. In addition, when the server can acquire the relative positional relationship between the photographing terminals, the server obtains the three-dimensional shape of the scene based on not only the two-dimensional moving image but also the video obtained by photographing the same scene from different angles. Can be generated. The server may separately encode the three-dimensional data generated by the point cloud or the like, and the video to be transmitted to the receiving terminal based on the result of recognizing or tracking the person or the object using the three-dimensional data. Alternatively, the images may be selected or reconstructed from videos captured by a plurality of terminals.

In this way, the user can arbitrarily select each video corresponding to each photographing terminal and enjoy a scene, or can display a video of an arbitrary viewpoint from three-dimensional data reconstructed using a plurality of images or videos. You can also enjoy the clipped content. Furthermore, as with video, sound is collected from a plurality of different angles, and the server may multiplex and transmit sound from a specific angle or space according to the video.

Also, in recent years, content that associates the real world with the virtual world, such as Virtual Reality (VR) and Augmented Reality (AR), has become widespread. In the case of a VR image, the server may create viewpoint images for the right eye and the left eye, respectively, and perform encoding that allows reference between each viewpoint video by Multi-View Coding (MVC) or the like. You may encode as another stream, without referring. At the time of decoding another stream, it is preferable to reproduce in synchronization with each other so that a virtual three-dimensional space is reproduced according to the viewpoint of the user.

In the case of an AR image, the server superimposes virtual object information in the virtual space on the camera information in the real space based on the three-dimensional position or the movement of the user's viewpoint. The decoding device may acquire or hold virtual object information and three-dimensional data, generate a two-dimensional image according to the movement of the user's viewpoint, and create superimposition data by connecting them smoothly. Alternatively, the decoding device transmits the movement of the user's viewpoint to the server in addition to the request for the virtual object information, and the server creates superimposition data according to the movement of the viewpoint received from the three-dimensional data held in the server, The superimposed data may be encoded and distributed to the decoding device. Note that the superimposed data has an α value indicating transparency in addition to RGB, and the server sets the α value of a portion other than the object created from the three-dimensional data to 0 or the like, and the portion is transparent. May be encoded. Alternatively, the server may generate data in which a RGB value of a predetermined value is set as the background, such as a chroma key, and the portion other than the object is set to the background color.

Similarly, the decryption processing of the distributed data may be performed at each terminal as a client, may be performed on the server side, or may be performed in a shared manner. As an example, a terminal may once send a reception request to the server, receive content corresponding to the request at another terminal, perform a decoding process, and transmit a decoded signal to a device having a display. Regardless of the performance of the communicable terminal itself, it is possible to reproduce data with good image quality by distributing processing and selecting appropriate content. As another example, a part of a region such as a tile in which a picture is divided may be decoded and displayed on a viewer's personal terminal while receiving large-size image data on a TV or the like. Accordingly, it is possible to confirm at hand the area in which the person is responsible or the area to be confirmed in more detail while sharing the whole image.

In the future, in the situation where multiple short-distance, medium-distance, or long-distance wireless communications can be used regardless of whether indoors or outdoors, using a distribution system standard such as MPEG-DASH, It is expected that content is received seamlessly while switching appropriate data. Accordingly, the user can switch in real time while freely selecting a decoding device or a display device such as a display installed indoors or outdoors as well as his / her own terminal. Also, decoding can be performed while switching between a terminal to be decoded and a terminal to be displayed based on its own position information. This makes it possible to move while displaying map information on the wall surface of a neighboring building or a part of the ground in which a displayable device is embedded while moving to the destination. Also, access to encoded data on the network, such as when the encoded data is cached in a server that can be accessed from the receiving terminal in a short time, or copied to the edge server in the content delivery service. It is also possible to switch the bit rate of received data based on ease.

[Scalable coding]
The content switching will be described using a scalable stream that is compression-encoded by applying the moving image encoding method shown in each of the above embodiments shown in FIG. The server may have a plurality of streams of the same content and different quality as individual streams, but the temporal / spatial scalable implementation realized by dividing into layers as shown in the figure. The configuration may be such that the content is switched by utilizing the characteristics of the stream. In other words, the decoding side decides which layer to decode according to internal factors such as performance and external factors such as the state of communication bandwidth, so that the decoding side can combine low-resolution content and high-resolution content. You can switch freely and decrypt. For example, when the user wants to continue watching the video that was viewed on the smartphone ex115 while moving on a device such as an Internet TV after returning home, the device only has to decode the same stream to a different layer, so the load on the server side Can be reduced.

Further, as described above, the enhancement layer includes meta information based on image statistical information, etc., in addition to the configuration in which the picture is encoded for each layer and the enhancement layer exists above the base layer. The decoding side may generate content with high image quality by super-resolution of the base layer picture based on the meta information. Super-resolution may be either improvement of the SN ratio at the same resolution or enlargement of the resolution. The meta information includes information for specifying a linear or non-linear filter coefficient used for super-resolution processing, or information for specifying a parameter value in filter processing, machine learning, or least square calculation used for super-resolution processing. .

Alternatively, the picture may be divided into tiles or the like according to the meaning of the object in the image, and the decoding side may select only a part of the region by selecting the tile to be decoded. Also, by storing the object attributes (person, car, ball, etc.) and the position in the video (coordinate position in the same image, etc.) as meta information, the decoding side can determine the position of the desired object based on the meta information. Can be identified and the tile containing the object can be determined. For example, as shown in FIG. 30, the meta information is stored using a data storage structure different from the pixel data such as the SEI message in HEVC. This meta information indicates, for example, the position, size, or color of the main object.

Also, meta information may be stored in units composed of a plurality of pictures, such as streams, sequences, or random access units. Thereby, the decoding side can acquire the time when the specific person appears in the video, etc., and can match the picture in which the object exists and the position of the object in the picture by combining with the information in units of pictures.

[Web page optimization]
FIG. 31 is a diagram showing an example of a web page display screen on the computer ex111 or the like. FIG. 32 is a diagram illustrating a display screen example of a web page on the smartphone ex115 or the like. As shown in FIGS. 31 and 32, a web page may include a plurality of link images that are links to image content, and the appearance differs depending on the browsing device. When a plurality of link images are visible on the screen, the display device until the user explicitly selects the link image, or until the link image approaches the center of the screen or the entire link image enters the screen. The (decoding device) displays a still image or an I picture included in each content as a link image, displays a video like a gif animation with a plurality of still images or I pictures, or receives only a base layer to receive a video. Are decoded and displayed.

When the link image is selected by the user, the display device decodes the base layer with the highest priority. If there is information indicating that the HTML constituting the web page is scalable content, the display device may decode up to the enhancement layer. Also, in order to ensure real-time properties, the display device only decodes forward reference pictures (I picture, P picture, forward reference only B picture) before being selected or when the communication band is very strict. In addition, the delay between the decoding time of the first picture and the display time (delay from the start of content decoding to the start of display) can be reduced by displaying. Further, the display device may intentionally ignore the reference relationship of pictures and roughly decode all B pictures and P pictures with forward reference, and perform normal decoding as the number of received pictures increases over time.

[Automatic driving]
In addition, when transmitting and receiving still image or video data such as two-dimensional or three-dimensional map information for automatic driving or driving support of a car, the receiving terminal adds meta data to image data belonging to one or more layers. Weather or construction information may also be received and decoded in association with each other. The meta information may belong to a layer or may be simply multiplexed with image data.

In this case, since the car, drone, airplane, or the like including the receiving terminal moves, the receiving terminal transmits the position information of the receiving terminal at the time of the reception request, thereby seamless reception and decoding while switching the base stations ex106 to ex110. Can be realized. In addition, the receiving terminal can dynamically switch how much meta-information is received or how much map information is updated according to the user's selection, the user's situation, or the communication band state. become.

As described above, in the content supply system ex100, the encoded information transmitted by the user can be received, decoded and reproduced in real time by the client.

[Distribution of personal contents]
Further, the content supply system ex100 can perform not only high-quality and long-time content by a video distributor but also unicast or multicast distribution of low-quality and short-time content by an individual. Moreover, such personal contents are expected to increase in the future. In order to make personal content superior, the server may perform the encoding process after performing the editing process. This can be realized, for example, with the following configuration.

After shooting, the server performs recognition processing such as shooting error, scene search, semantic analysis, and object detection from the original image or encoded data. Then, the server manually or automatically corrects out-of-focus or camera shake based on the recognition result, or selects a less important scene such as a scene whose brightness is lower than that of other pictures or is out of focus. Edit such as deleting, emphasizing the edge of an object, and changing the hue. The server encodes the edited data based on the editing result. It is also known that if the shooting time is too long, the audience rating will decrease, and the server will move not only in the less important scenes as described above, but also in motion according to the shooting time. A scene with few images may be automatically clipped based on the image processing result. Alternatively, the server may generate and encode a digest based on the result of the semantic analysis of the scene.

In some cases, personal content may include infringements such as copyrights, author's personality rights, or portrait rights, which are inconvenient for individuals, such as exceeding the intended scope of sharing. In some cases. Therefore, for example, the server may change and encode the face of the person in the periphery of the screen or the inside of the house into an unfocused image. In addition, the server recognizes whether or not a face of a person different from the person registered in advance is shown in the encoding target image, and if so, performs processing such as applying a mosaic to the face part. May be. Alternatively, as a pre-processing or post-processing of encoding, the user designates a person or background area that the user wants to process an image from the viewpoint of copyright, etc., and the server replaces the designated area with another video or blurs the focus. It is also possible to perform such processing. If it is a person, the face image can be replaced while tracking the person in the moving image.

In addition, since viewing of personal content with a small amount of data is strongly demanded for real-time performance, the decoding device first receives the base layer with the highest priority and performs decoding and reproduction, depending on the bandwidth. The decoding device may receive the enhancement layer during this time, and may play back high-quality video including the enhancement layer when played back twice or more, such as when playback is looped. A stream that is scalable in this way can provide an experience in which the stream becomes smarter and the image is improved gradually, although it is a rough moving picture when it is not selected or at the beginning of viewing. In addition to scalable coding, the same experience can be provided even if the coarse stream played back the first time and the second stream coded with reference to the first video are configured as one stream. .

[Other usage examples]
In addition, these encoding or decoding processes are generally processed in the LSI ex500 included in each terminal. The LSI ex500 may be configured as a single chip or a plurality of chips. Note that moving image encoding or decoding software is incorporated into some recording medium (CD-ROM, flexible disk, hard disk, etc.) that can be read by the computer ex111 and the like, and encoding or decoding processing is performed using the software. Also good. Furthermore, when the smartphone ex115 has a camera, moving image data acquired by the camera may be transmitted. The moving image data at this time is data encoded by the LSI ex500 included in the smartphone ex115.

Note that the LSI ex500 may be configured to download and activate application software. In this case, the terminal first determines whether the terminal is compatible with the content encoding method or has a specific service execution capability. If the terminal does not support the content encoding method or does not have the capability to execute a specific service, the terminal downloads a codec or application software, and then acquires and reproduces the content.

Further, not only the content supply system ex100 via the Internet ex101, but also a digital broadcasting system, at least the moving image encoding device (image encoding device) or the moving image decoding device (image decoding device) of the above embodiments. Any of these can be incorporated. The difference is that the unicasting of the content supply system ex100 is suitable for multicasting because it uses a satellite or the like to transmit and receive multiplexed data in which video and sound are multiplexed on broadcasting radio waves. However, the same application is possible for the encoding process and the decoding process.

[Hardware configuration]
FIG. 33 is a diagram illustrating the smartphone ex115. FIG. 34 is a diagram illustrating a configuration example of the smartphone ex115. The smartphone ex115 receives the antenna ex450 for transmitting / receiving radio waves to / from the base station ex110, the camera unit ex465 capable of taking video and still images, the video captured by the camera unit ex465, and the antenna ex450. A display unit ex458 for displaying data obtained by decoding the video or the like. The smartphone ex115 further includes an operation unit ex466 that is a touch panel or the like, a voice output unit ex457 that is a speaker or the like for outputting voice or sound, a voice input unit ex456 that is a microphone or the like for inputting voice, and photographing. Memory unit ex467 that can store encoded video or still image, recorded audio, received video or still image, encoded data such as mail, or decoded data, and a user, and network A slot part ex464, which is an interface part with the SIMex 468 for authenticating access to various data. An external memory may be used instead of the memory unit ex467.

Also, a main control unit ex460 that comprehensively controls the display unit ex458, the operation unit ex466, and the like, a power supply circuit unit ex461, an operation input control unit ex462, a video signal processing unit ex455, a camera interface unit ex463, a display control unit ex459, a modulation / Demodulation unit ex452, multiplexing / demultiplexing unit ex453, audio signal processing unit ex454, slot unit ex464, and memory unit ex467 are connected via bus ex470.

When the power key is turned on by a user operation, the power supply circuit unit ex461 starts up the smartphone ex115 in an operable state by supplying power from the battery pack to each unit.

The smartphone ex115 performs processing such as calling and data communication based on the control of the main control unit ex460 having a CPU, a ROM, a RAM, and the like. During a call, the voice signal picked up by the voice input unit ex456 is converted into a digital voice signal by the voice signal processing unit ex454, spread spectrum processing is performed by the modulation / demodulation unit ex452, and digital / analog conversion is performed by the transmission / reception unit ex451. After performing the processing and the frequency conversion processing, the data is transmitted via the antenna ex450. Further, the received data is amplified and subjected to frequency conversion processing and analog-digital conversion processing, spectrum despreading processing is performed by the modulation / demodulation unit ex452, and converted to analog audio signal by the audio signal processing unit ex454, and then this is output to the audio output unit ex457. Output from. In the data communication mode, text, still image, or video data is sent to the main control unit ex460 via the operation input control unit ex462 by the operation of the operation unit ex466 of the main body unit, and transmission / reception processing is performed similarly. When transmitting video, still image, or video and audio in the data communication mode, the video signal processing unit ex455 uses the video signal stored in the memory unit ex467 or the video signal input from the camera unit ex465 as described above. The video data is compressed and encoded by the moving image encoding method shown in the form, and the encoded video data is sent to the multiplexing / demultiplexing unit ex453. The audio signal processing unit ex454 encodes the audio signal picked up by the audio input unit ex456 while the camera unit ex465 captures a video or a still image, and sends the encoded audio data to the multiplexing / separating unit ex453. To do. The multiplexing / demultiplexing unit ex453 multiplexes the encoded video data and the encoded audio data by a predetermined method, and the modulation / demodulation unit (modulation / demodulation circuit unit) ex452 and the modulation / demodulation unit ex451 perform modulation processing and conversion. The data is processed and transmitted via the antenna ex450.

In order to decode the multiplexed data received via the antenna ex450 when the video attached to the e-mail or chat, or the video linked to the web page or the like is received, the multiplexing / demultiplexing unit ex453 performs multiplexing By separating the data, the multiplexed data is divided into a bit stream of video data and a bit stream of audio data, and the encoded video data is supplied to the video signal processing unit ex455 via the synchronization bus ex470. The converted audio data is supplied to the audio signal processing unit ex454. The video signal processing unit ex455 decodes the video signal by the video decoding method corresponding to the video encoding method shown in each of the above embodiments, and is linked from the display unit ex458 via the display control unit ex459. A video or still image included in the moving image file is displayed. The audio signal processing unit ex454 decodes the audio signal, and the audio is output from the audio output unit ex457. Since real-time streaming is widespread, depending on the user's situation, there may be occasions where audio playback is not socially appropriate. Therefore, it is desirable that the initial value is a configuration in which only the video data is reproduced without reproducing the audio signal. Audio may be synchronized and played back only when the user performs an operation such as clicking on video data.

In addition, although the smartphone ex115 has been described here as an example, in addition to a transmission / reception terminal having both an encoder and a decoder as a terminal, a transmission terminal having only an encoder and a reception having only a decoder There are three possible mounting formats: terminals. Furthermore, in the digital broadcasting system, it has been described as receiving or transmitting multiplexed data in which audio data or the like is multiplexed with video data. However, multiplexed data includes character data related to video in addition to audio data. Multiplexing may be performed, and video data itself may be received or transmitted instead of multiplexed data.

In addition, although it has been described that the main control unit ex460 including the CPU controls the encoding or decoding process, the terminal often includes a GPU. Therefore, a configuration may be adopted in which a wide area is processed in a lump by utilizing the performance of the GPU by using a memory shared by the CPU and the GPU or a memory whose addresses are managed so as to be used in common. As a result, the encoding time can be shortened, real-time performance can be ensured, and low delay can be realized. In particular, it is efficient to perform motion search, deblocking filter, SAO (Sample Adaptive Offset), and transformation / quantization processing in batches in units of pictures or the like instead of the CPU.

The present disclosure can be used for, for example, a television receiver, a digital video recorder, a car navigation, a mobile phone, a digital camera, a digital video camera, a video conference system, or an electronic mirror.

DESCRIPTION OF SYMBOLS 100 Coding apparatus 102 Division | segmentation part 104 Subtraction part 106 Conversion part 108 Quantization part 110 Entropy encoding part 112,204 Inverse quantization part 114,206 Inverse conversion part 116,208 Adder 118,210 Block memory 120,212

Loop filter Unit

122, 214

Frame memory

124, 216 Intra prediction unit (intra-screen prediction unit)
126, 218 Inter prediction unit (inter-screen prediction unit)
128, 220

Prediction control unit

160, 260

Circuit

162, 262 Memory 200 Decoding device 202 Entropy decoding unit

Claims

An encoding device that encodes a moving image by performing motion compensation,
Memory,
A circuit capable of accessing the memory,
The circuit accessible to the memory is:
Deriving a motion vector of an image block in the moving image;
Performing the motion compensation in units of the block or in units of sub-blocks constituting the block;
When the motion vector of the block is derived using a template FRUC (Frame Rate Up-Conversion) method and the motion compensation is performed in units of the sub-block, the motion vector of the sub-block is derived using a bilateral FRUC method, Performing the motion compensation in units of sub-blocks using sub-block motion vectors;
In the template FRUC method, a motion vector of a processing target area that is the block or the sub-block is derived according to the degree of matching between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture. It is a method to
The bilateral FRUC method is a method of deriving a motion vector of the processing target region in accordance with the degree of matching between two reconstructed images of two regions in two different reference pictures.
In the case where the circuit performs the motion compensation in the unit of the block or the unit of the sub-block by deriving the motion vector of the block by the template FRUC method,
If the motion vector of the block is a unidirectional motion vector, the motion compensation is performed in units of the block using the motion vector of the block;
The encoding apparatus according to claim 1, wherein when the motion vector of the block is a bi-directional motion vector, the motion compensation is performed in units of the sub block using the motion vector of the sub block.
The circuit derives a motion vector of the sub-block using the bilateral FRUC method when the motion vector of the block is derived using the bi-lateral FRUC method and the motion compensation is performed in units of the sub-block. The encoding apparatus according to claim 1 or 2, wherein the motion compensation is performed in units of the sub-block using a motion vector of the sub-block.
When deriving a motion vector for the sub-block, the circuit derives a motion vector candidate for the sub-block using the motion vector for the block, and determines a motion vector for the sub-block using the derived candidate. The encoding apparatus according to any one of claims 1 to 3.
A decoding device for decoding a moving image by performing motion compensation,
Memory,
A circuit capable of accessing the memory,
The circuit accessible to the memory is:
Deriving a motion vector of an image block in the moving image;
Performing the motion compensation in units of the block or in units of sub-blocks constituting the block;
When the motion vector of the block is derived using a template FRUC (Frame Rate Up-Conversion) method and the motion compensation is performed in units of the sub-block, the motion vector of the sub-block is derived using a bilateral FRUC method, Performing the motion compensation in units of sub-blocks using sub-block motion vectors;
In the template FRUC method, a motion vector of a processing target area that is the block or the sub-block is derived according to the degree of matching between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture. It is a method to
The bilateral FRUC method is a method of deriving a motion vector of the processing target region according to a degree of matching between two reconstructed images of two regions in two different reference pictures.
In the case where the circuit performs the motion compensation in the unit of the block or the unit of the sub-block by deriving the motion vector of the block by the template FRUC method,
If the motion vector of the block is a unidirectional motion vector, the motion compensation is performed in units of the block using the motion vector of the block;
The decoding device according to claim 5, wherein when the motion vector of the block is a bi-directional motion vector, the motion compensation is performed in units of the sub block using the motion vector of the sub block.
The circuit derives a motion vector of the sub-block using the bilateral FRUC method when the motion vector of the block is derived using the bi-lateral FRUC method and the motion compensation is performed in units of the sub-block. The decoding device according to claim 5 or 6, wherein the motion compensation is performed in units of the sub-block using a motion vector of the sub-block.
When deriving a motion vector for the sub-block, the circuit derives a motion vector candidate for the sub-block using the motion vector for the block, and determines a motion vector for the sub-block using the derived candidate. The decoding device according to any one of claims 5 to 7.
An encoding method for encoding a moving image by performing motion compensation,
Deriving a motion vector of an image block in the moving image;
Performing the motion compensation in units of the block or in units of sub-blocks constituting the block;
When the motion vector of the block is derived using a template FRUC (Frame Rate Up-Conversion) method and the motion compensation is performed in units of the sub-block, the motion vector of the sub-block is derived using a bilateral FRUC method, Performing the motion compensation in units of sub-blocks using sub-block motion vectors;
In the template FRUC method, a motion vector of a processing target area that is the block or the sub-block is derived according to the degree of matching between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture. It is a method to
The bilateral FRUC method is a method of deriving a motion vector of the processing target region according to the degree of matching between two reconstructed images of two regions in two different reference pictures.
A decoding method for decoding a moving image by performing motion compensation,
Deriving a motion vector of an image block in the moving image;
Performing the motion compensation in units of the block or in units of sub-blocks constituting the block;
When the motion vector of the block is derived using a template FRUC (Frame Rate Up-Conversion) method and the motion compensation is performed in units of the sub-block, the motion vector of the sub-block is derived using a bilateral FRUC method, Performing the motion compensation in units of sub-blocks using sub-block motion vectors;
In the template FRUC method, a motion vector of a processing target area that is the block or the sub-block is derived according to the degree of matching between the reconstructed image of the area adjacent to the processing target area and the reconstructed image of the area in the reference picture It is a method to
The bilateral FRUC method is a method of deriving a motion vector of the processing target region according to a degree of matching between two reconstructed images of two regions in two different reference pictures.