WO2019087978A1

WO2019087978A1 - Coding device, decoding device, coding method and decoding method

Info

Publication number: WO2019087978A1
Application number: PCT/JP2018/039942
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: 2017-10-30
Filing date: 2018-10-26
Publication date: 2019-05-09

Abstract

A coding device (100) is provided with a circuit (160) and a memory (162), wherein the circuit (160) sets a search range that is used in common by first processing units, using the memory (162) (S201), and performs coding processing with respect to a second processing unit that uses inter prediction, among one or more second processing units included in the first processing unit, with reference to pixels within the search range while restricting reference to pixels outside the search range (S204, S210). For example, the first processing unit may be a block unit being a basic division unit of a picture and composed of one or more second processing units, or a block unit of a predefined size composed of one or more second processing units.

Description

Encoding device, decoding device, encoding method and decoding method

The present disclosure relates to an encoding device, a decoding device, an encoding method, and a decoding method.

Conventionally, as a standard for coding a moving image, H.264 is used. There are 265. H. H.265 is also referred to as HEVC (High Efficiency Video Coding).

In such encoding method and decoding method, it is desired that processing time or processing amount can be reduced.

The present disclosure aims to provide an encoding device, a decoding device, an encoding method, or a decoding method that can reduce processing time or processing amount.

An encoding device according to an aspect of the present disclosure includes a circuit and a memory, and the circuit uses the memory to set a search range to be commonly used in a first processing unit, and the first processing. For the second processing unit using inter prediction among one or more second processing units included in the unit, reference to pixels outside the search range is restricted, and encoding is performed with reference to pixels in the search range Do the processing.

A decoding device according to an aspect of the present disclosure includes a circuit and a memory, and the circuit uses the memory to set a search range commonly used in the first processing unit, and the first processing unit. For the second processing unit using inter prediction among the plurality of second processing units included in, the reference of the pixels outside the search range is restricted, and the decoding process is performed using the pixels within the search range.

Note that these general 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, and the system The present invention may be realized as any combination of an apparatus, a method, an integrated circuit, a computer program, and a storage medium.

The present disclosure can provide an encoding device, a decoding device, an encoding method, or a decoding method that can reduce processing time or processing amount.

FIG. 1 is a block diagram showing a functional configuration of the coding apparatus according to the first embodiment. FIG. 2 is a diagram showing an example of block division in the first embodiment. FIG. 3 is a table showing transform basis functions corresponding to each transform type. FIG. 4A is a view showing an example of the shape of a filter used in ALF. FIG. 4B is a view showing another example of the shape of a filter used in ALF. FIG. 4C is a view showing 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 describing an outline of predicted image correction processing by OBMC processing. FIG. 5C is a conceptual diagram for describing an outline of predicted image correction processing by OBMC processing. FIG. 5D is a diagram illustrating an example of FRUC. FIG. 6 is a diagram for describing pattern matching (bilateral matching) between two blocks along a motion trajectory. FIG. 7 is a diagram for describing pattern matching (template matching) between a template in a current picture and a block in a reference picture. FIG. 8 is a diagram for explaining a model assuming uniform linear motion. FIG. 9A is a diagram for describing 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 describing an overview of motion vector derivation processing in the merge mode. FIG. 9C is a conceptual diagram for describing an overview of DMVR processing. FIG. 9D is a diagram for describing an outline 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 flowchart of a first example of inter prediction processing according to the first embodiment. FIG. 12 is a diagram for describing a process of excluding candidate motion vectors from evaluation targets in the first example of the inter prediction process according to the first embodiment. FIG. 13 is a diagram for explaining the process of determining the search range according to the first embodiment. FIG. 14 is a diagram for describing a method of deriving the center position shift amount of the search area according to the first embodiment for each target CTU. FIG. 15 is a diagram for describing a method of deriving the center position shift amount of the search area according to Embodiment 1 as a value common to all CTUs in the target picture. FIG. 16A is a diagram for describing a data transfer method in the first example of the inter prediction process according to the first embodiment. 16B is a diagram for describing a data transfer method in the first example of the inter prediction process according to Embodiment 1. FIG. FIG. 17A is a diagram for explaining a pixel area which requires data transfer. FIG. 17B is a diagram for explaining a pixel area which requires data transfer. FIG. 17C is a diagram for explaining a pixel area which requires data transfer. FIG. 18 is a flowchart of a second example of the inter prediction process according to the first embodiment. FIG. 19 is a diagram for describing a process of excluding candidate motion vectors from evaluation targets in the second example of the inter prediction process according to the first embodiment. FIG. 20A is a diagram for describing a data transfer method in the second example of the inter prediction process according to the first embodiment. FIG. 20B is a diagram for describing a data transfer method in the second example of the inter prediction process according to the first embodiment. FIG. 21 is a block diagram showing an implementation example of a coding apparatus. FIG. 22 is a block diagram showing an implementation example of the decoding device. FIG. 23 is an overall configuration diagram of a content supply system for realizing content distribution service. FIG. 24 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 25 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 26 is a diagram showing an example of a display screen of a web page. FIG. 27 is a diagram showing an example of a display screen of a web page. FIG. 28 is a diagram illustrating an example of a smartphone. FIG. 29 is a block diagram showing a configuration example of a smartphone.

According to this, since the amount of access to the memory storing the image of the processed area can be limited, the processing time related to data transfer can be suppressed, and the amount of processing can be reduced.

For example, the first processing unit may be a block unit configured of one or more second processing units, which is a basic division unit of a picture, or a predefined unit configured of one or more second processing units. It may be a block unit of another size.

For example, in the motion compensation process using a motion vector assigned to an inter prediction mode to be selected among a plurality of inter prediction modes with respect to a target second processing unit included in the first processing unit, the search range An inter prediction mode that refers to an outer pixel may be excluded, one mode may be selected from the inter prediction mode after the exclusion and the intra prediction mode, and the encoding process may be performed using the selected mode.

For example, in the exclusion of the inter prediction mode, pixels outside the search range are further required in another process related to predicted image generation applied other than the motion compensation process in the inter prediction mode to be selected. Inter prediction mode may be excluded.

For example, in the inter prediction mode to be selected, there is another process related to predicted image generation to be applied other than the motion compensation process, and there is the other process requiring pixels outside the search range, The predicted image may be generated without performing the other processing.

For example, in the setting of the search range, the search range using information including a processed processed picture, the size of a search area in the processed picture, and the center position shift amount of the search area in the processed picture May be set.

For example, the size of the search area may be switched according to the number of processed reference pictures.

For example, the size of the search area may be set such that the sum of the search areas in the referenceable processed picture is less than or equal to a specific value.

For example, the upper limit of the number of processable pictures that can be referred to and the size of the search area or the total sum of the search areas is defined in association with the profile value or the level value, and the profile assigned to the target stream The number of referable processed pictures and the size of the search area may be set according to the value or the level value so as to be a value equal to or less than the upper limit value.

For example, information indicating that the inter prediction mode requiring the pixels outside the search range is not selected in all the second processing units included in the first processing unit is a sequence header area, a picture header area, It may be encoded in the slice header area or the side information area.

For example, according to the processing capability of the decoding device, it may be switched whether to exclude the inter prediction mode that refers to the pixels outside the search range.

For example, whether to exclude an inter prediction mode that refers to a pixel outside the search range may be switched according to a profile value or a level value assigned to a target stream.

For example, whether to exclude an inter prediction mode that refers to a pixel outside the search range may be switched according to the size of the target picture.

For example, the center position shift amount of the search area may be a shift amount between the position of the target first processing unit in the target picture and the position of the search area in the processed picture to be referred to.

For example, the center position shift amount of the search area may be derived for each first processing unit.

For example, the center position shift amount of the search area is derived using the motion vector assigned to the second processing unit included in the processed first processing unit located in the spatial or temporal periphery of the target first processing unit. You may

For example, the processed first processing unit may be a processed first processing unit other than the first processing unit in which the processing order is immediately before the target first processing unit.

For example, as the center position shift amount of the search area, a value common to all the first processing units included in the target picture or target slice is set, and the information for specifying the common value is a picture. It may be encoded in the header area or slice header area.

For example, the common value may be set to a value at which the shift of the center position is zero.

For example, the common value may be derived using statistics of a plurality of motion vectors derived in a plurality of second processing units included in the processed picture.

For example, when the position of the search range is specified, transfer of reference pixel data of the search range set for the target first processing unit is started from the memory storing image data of a processed picture. The processing of the target first processing unit may be started after the transfer is completed.

For example, without waiting for the processing of the first processing unit whose processing order is immediately before, reference to the search range set for the target first processing unit from the memory storing the image data of the processed picture Transfer of pixel data may be started.

For example, among reference pixel data of the search range set for the target first processing unit, reference pixel data of an area overlapping the search range set for the already processed first processing unit Alternatively, the reference pixel data may be transferred from the memory.

For example, among the plurality of second processing units included in the first processing unit, reference to pixels outside the search range is restricted with respect to the second processing unit using the FRUC mode, and pixels within the search range The encoding process may be performed with reference to FIG.

For example, in the FRUC mode, candidate motion vectors with reference to pixels outside the search range are excluded from evaluation targets from a plurality of candidate motion vectors derived from motion vectors of processed blocks, and candidate motion vectors after exclusion are excluded. Cost evaluation.

For example, in the exclusion of the candidate motion vector, a candidate motion vector requiring a pixel outside the search range is further excluded from the evaluation target in another process related to prediction image generation applied after performing the FRUC process. May be

For example, in the FRUC mode, there is another process related to predicted image generation applied after performing the FRUC process and there is the other process requiring a pixel outside the search range. The predicted image may be generated without processing.

For example, the setting of the search range includes a reference index for specifying a processed picture that can be referred to, the size of a search area in the reference index, and the shift amount of the center position of the search area in the reference index. Information may be used to set the search range.

For example, the size of the search area may be switched according to the total number of reference indexes.

For example, the size of the search area may be set such that the sum of the search areas in the reference index is less than or equal to a specific value.

For example, the upper limit value of the total number of reference indexes and the size of the search area or the total sum of the search areas is defined in association with the profile value or the level value, and is defined as the profile value or the level value assigned to the target stream Accordingly, the total number of reference indexes and the size of the search area may be set so as to be a value equal to or less than the upper limit value.

For example, a plurality of reference indexes may be associated with one referenceable processed picture.

For example, even if the reference index for specifying the referenceable processed picture and the information for specifying the size of the search area are encoded in the sequence header area, the picture header area, the slice header area or the auxiliary information area Good.

For example, the total number of reference indexes and the size of the search area may be switched according to the processing capability of the decoding device.

For example, the total number of reference indexes and the size of the search area may be switched according to a profile value or a level value assigned to a target stream.

For example, the total number of reference indexes and the size of the search area may be switched according to the size of the target picture.

For example, a method of deriving the center position shift amount of the search area for each first processing unit, and a method of setting a common value to all the first processing units belonging to the target picture or target slice, 2 One method may be switched for each target picture.

For example, information for specifying which of the two methods is used may be encoded in the picture header area or slice header area.

According to this, since the amount of access to the memory storing the image of the processed area can be limited, the processing time related to data transfer can be suppressed and the amount of processing can be reduced.

For example, information indicating that the inter prediction mode requiring the pixels outside the search range is not selected in all the second processing units included in the first processing unit is a sequence header area, a picture header area, It may be decoded from the slice header area or the side information area.

For example, as the center position shift amount of the search area, a common value is set to all the first processing units included in the target picture or the target slice, and the information for specifying the common value is a picture The common value may be identified by decoding from the header area or slice header area.

For example, among the one or more second processing units included in the first processing unit, reference to pixels outside the search range is restricted with respect to the second processing unit using the FRUC mode, and Decoding processing may be performed using pixels.

For example, the reference index for specifying the referenceable processed picture and the information for specifying the size of the search area are decoded from the sequence header area, the picture header area, the slice header area or the auxiliary information area, A reference index and the size of the search area may be specified.

For example, information for specifying which of the two methods is to be used may be decoded from the picture header area or the slice header area, and it may be specified which of the two methods is to be used.

The encoding method according to an aspect of the present disclosure sets a search range to be commonly used in the first processing unit, and uses inter prediction among the one or more second processing units included in the first processing unit. For two processing units, reference to pixels outside the search range is restricted, and coding processing is performed with reference to pixels in the search range.

The decoding method according to an aspect of the present disclosure sets a search range to be commonly used in the first processing unit, and a second processing unit using inter prediction among the plurality of second processing units included in the first processing unit. On the other hand, the reference of pixels outside the search range is restricted, and the decoding process is performed using the pixels within the search range.

Furthermore, these general 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, and the system The present invention may be realized as any combination of an apparatus, a method, an integrated circuit, a computer program, and a storage medium.

Embodiments will be specifically described below with reference to the drawings.

The embodiments described below are all inclusive or specific examples. 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. Further, among the components in the following embodiments, components not described in the independent claim indicating the highest concept are described as arbitrary components.

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

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

(1) The encoding apparatus or the 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 that configure the encoding apparatus or the decoding apparatus. Replacing a component with a component described in each aspect of the present disclosure (2) A plurality of configurations constituting the encoding device or the decoding device with respect to the encoding device or the decoding device of the first embodiment A component corresponding to the component described in each aspect of the present disclosure, after any change such as addition, replacement, or deletion of a function or processing to be performed on a part of components among elements, is disclosed (3) Addition of processing to the method performed by the encoding apparatus or the decoding apparatus of the first embodiment, and / or a plurality of processes included in the method home Replacing a process corresponding to the process described in each aspect of the present disclosure with the process described in each aspect of the present disclosure after replacing some of the processes and arbitrary changes such as deletion. The component described in each aspect of the present disclosure, the component described in each aspect of the present disclosure is a component of a part of the plurality of components constituting the encoding apparatus or the decoding apparatus of the first aspect Implementing in combination with a component having a part of the functions to be provided or a component performing a part of the process performed by the component described in each aspect of the present disclosure (5) The encoding apparatus according to the first embodiment Or a component having a part of functions provided by a part of a plurality of components constituting the decoding apparatus, or a plurality of components constituting the coding apparatus or the decoding apparatus of the first embodiment Part of A component performing a part of the process performed by the component is a component described in each aspect of the present disclosure, a component provided with a part of the function of the component described in each aspect of the present disclosure, or the present Implementing in combination with a component that performs part of the processing performed by the components described in each aspect of the disclosure (6) For the method performed by the encoding apparatus or the decoding apparatus according to the first embodiment Replacing the processing corresponding to the processing described in each aspect of the present disclosure among the plurality of processing included in the method with the processing described in each aspect of the present disclosure (7) The encoding apparatus according to the first embodiment or Implementing some of the plurality of processes included in the method performed by the decoding device in combination with the processes described in each aspect of the present disclosure

Note that the manner of implementation of the processing and / or configuration described in each aspect of the present disclosure is not limited to the above example. For example, it may be implemented in an apparatus used for a purpose different from the moving picture / image coding apparatus or the moving picture / image decoding apparatus disclosed in the first embodiment, or the process and / or the process described in each aspect. The configuration may be implemented alone. Also, the processes and / or configurations described in the different embodiments may be implemented in combination.

[Overview of Encoding Device]
First, an outline of the coding apparatus according to Embodiment 1 will be described. FIG. 1 is a block diagram showing a functional configuration of coding apparatus 100 according to the first embodiment. The encoding device 100 is a moving image / image coding device that encodes a moving image / image in units of blocks.

As shown in FIG. 1, the encoding apparatus 100 is an apparatus for encoding an image in units of blocks, and includes a dividing unit 102, a subtracting unit 104, a converting unit 106, a quantizing unit 108, and entropy coding. Unit 110, inverse quantization unit 112, inverse transformation unit 114, addition unit 116, block memory 118, loop filter unit 120, frame memory 122, intra prediction unit 124, inter prediction unit 126, And 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 controls the division unit 102, the subtraction unit 104, the conversion unit 106, the quantization unit 108, the entropy coding unit 110, and the dequantization unit 112. The inverse transform unit 114, the addition unit 116, the loop filter unit 120, the intra prediction unit 124, the inter prediction unit 126, and the prediction control unit 128 function. In addition, coding apparatus 100 includes division section 102, subtraction section 104, conversion section 106, quantization section 108, entropy coding section 110, inverse quantization section 112, inverse conversion section 114, addition section 116, and loop filter section 120. , And may be realized as one or more dedicated electronic circuits corresponding to the intra prediction unit 124, the inter prediction unit 126, and the prediction control unit 128.

Each component included in the encoding device 100 will be described below.

[Division]
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 division 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 fixed size blocks into blocks of variable size (for example, 64 × 64 or less) based on recursive quadtree and / or binary tree block division. . This variable sized block may be referred to as a coding unit (CU), a prediction unit (PU) or a transform unit (TU). In the present embodiment, CUs, PUs, and TUs need not be distinguished, and some or all of the blocks in a picture may be processing units of CUs, PUs, and TUs.

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

Here, the block 10 is a square block (128 × 128 block) of 128 × 128 pixels. The 128x128 block 10 is first divided into four square 64x64 blocks (quadtree block division).

The upper left 64x64 block is further vertically divided into two rectangular 32x64 blocks, and the left 32x64 block is further vertically divided into two rectangular 16x64 blocks (binary block division). As a result, the upper left 64x64 block is divided into two 16x64 blocks 11, 12 and a 32x64 block 13.

The upper right 64x64 block is divided horizontally into two rectangular 64x32 blocks 14 and 15 (binary block division).

The lower left 64x64 block is divided into four square 32x32 blocks (quadtree block division). Of the four 32x32 blocks, the upper left block and the lower right block are further divided. The upper left 32x32 block is vertically divided into two rectangular 16x32 blocks, and the right 16x32 block is further horizontally split into two 16x16 blocks (binary block division). The lower right 32x32 block is divided horizontally into two 32x16 blocks (binary block division). As a result, the lower left 64x64 block is divided into a 16x32 block 16, two 16x16 blocks 17, 18, two 32x32 blocks 19, 20, and two 32x16 blocks 21, 22.

The lower right 64x64 block 23 is not divided.

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

Although one block is divided into four or two blocks (quadtree or binary tree block division) in FIG. 2, the division is not limited to this. For example, one block may be divided into three blocks (tri-tree block division). A partition including such a ternary tree block partition may be referred to as a multi type tree (MBT) partition.

[Subtractor]
The subtracting unit 104 subtracts a prediction signal (prediction sample) from an original signal (original sample) in block units divided by the dividing unit 102. That is, the subtraction unit 104 calculates a prediction error (also referred to as a residual) of the encoding target block (hereinafter, referred to as a current block). Then, the subtracting unit 104 outputs the calculated prediction error to the converting unit 106.

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

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

Transform section 106 adaptively selects a transform type from among a plurality of transform types, and transforms the prediction error into transform coefficients using a transform basis function corresponding to the selected transform type. You may Such transformation may be referred to as explicit multiple core transform (EMT) or adaptive multiple transform (AMT).

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

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

Also, the conversion unit 106 may re-convert the conversion coefficient (conversion result). Such reconversion may be referred to as adaptive secondary transform (AST) or non-separable secondary transform (NSST). For example, the transform unit 106 performs retransformation for each sub block (for example, 4 × 4 sub blocks) included in the block of transform coefficients corresponding to the intra prediction error. The information indicating whether to apply the NSST and the information on the transformation matrix used for the NSST are signaled at the CU level. Note that the signaling of these pieces of information need not be limited to the CU level, but may be at other levels (eg, sequence level, picture level, slice level, tile level or CTU level).

Here, Separable conversion is a method in which conversion is performed multiple times by separating in each direction as many as the number of dimensions of the input, and Non-Separable conversion is two or more when the input is multidimensional. This is a method of collectively converting the dimensions of 1 and 2 into one dimension.

For example, as an example of Non-Separable conversion, if the input is a 4 × 4 block, it is regarded as one array having 16 elements, and 16 × 16 conversion is performed on the array There is one that performs transformation processing with a matrix.

Similarly, if you consider 4x4 input blocks as one array with 16 elements, you can perform multiple Givens rotation on the array (Hypercube Givens Transform) as Non-Separable as well. It is an example of conversion.

[Quantizer]
The quantization unit 108 quantizes the transform coefficient output from the transform unit 106. Specifically, the quantization unit 108 scans the transform coefficient of the current block in a predetermined scan order, and quantizes the transform coefficient based on the quantization parameter (QP) corresponding to the scanned transform coefficient. Then, the quantization unit 108 outputs the quantized transform coefficient of the current block (hereinafter, referred to as a quantization coefficient) to the entropy coding 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 scan order is defined in ascending order (low frequency to high frequency) or descending order (high frequency to low frequency) of the 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, as the value of the quantization parameter increases, the quantization error increases.

[Entropy coding unit]
The entropy coding unit 110 generates a coded signal (coded bit stream) by subjecting the quantization coefficient input from the quantization unit 108 to variable-length coding. Specifically, for example, the entropy coding unit 110 binarizes the quantization coefficient and performs arithmetic coding on the binary signal.

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

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

The restored prediction error does not match the prediction error calculated by the subtracting unit 104 because the information is lost due to quantization. That is, the restored prediction error includes the quantization error.

[Adder]
The addition unit 116 reconstructs the current block by adding the prediction error, which is the input from the inverse conversion unit 114, and the prediction sample, which is the input from the prediction control unit 128. Then, the addition unit 116 outputs the reconstructed block to the block memory 118 and the loop filter unit 120. Reconstruction blocks may also be referred to as local decoding blocks.

[Block memory]
The block memory 118 is a storage unit for storing a block in an encoding target picture (hereinafter referred to as a current picture) which is a block 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 coding 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 squares error filter is applied to remove coding distortion, for example, multiple 2x2 subblocks in the current block, based on local gradient direction and activity. One filter selected from the filters is applied.

Specifically, first, subblocks (for example, 2x2 subblocks) are classified into a plurality of classes (for example, 15 or 25 classes). Sub-block classification is performed based on the gradient direction and activity. For example, the classification value C (for example, C = 5 D + 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 the subblock is determined among the plurality of filters.

For example, a circularly symmetrical shape is used as the shape of the filter used in ALF. FIGS. 4A to 4C are diagrams showing a plurality of examples of filter shapes used in ALF. FIG. 4A shows a 5 × 5 diamond shaped filter, FIG. 4B shows a 7 × 7 diamond shaped filter, and FIG. 4C shows a 9 × 9 diamond shaped filter. Information indicating the shape of the filter is signaled at the picture level. Note that the signaling of the information indicating the shape of the filter does not have to be limited to the picture level, and may be another level (for example, sequence level, slice level, tile level, CTU level or CU level).

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

The set of coefficients of the plurality of selectable filters (eg, up to 15 or 25 filters) is signaled at the picture level. Note that the signaling of the coefficient set need not be limited to the picture level, but may be other levels (eg, 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 may be referred to as a frame buffer. Specifically, the frame memory 122 stores the reconstructed block filtered by the loop filter unit 120.

[Intra prediction unit]
The intra prediction unit 124 generates a prediction signal (intra prediction signal) by performing intra prediction (also referred to as in-screen prediction) of the current block with reference to a block in the current picture stored in the block memory 118. Specifically, the intra prediction unit 124 generates an intra prediction signal by performing intra prediction with reference to samples (for example, luminance value, color difference value) of a block adjacent to the current block, and performs prediction control on the intra prediction signal. Output to the part 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 described in, for example, H.264. It includes Planar prediction mode and DC prediction mode defined in H.265 / High-Efficiency Video Coding (HEVC) standard (Non-Patent Document 1).

The plurality of directionality prediction modes are, for example, H.264. It includes 33 directional prediction modes defined by 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 showing 67 intra prediction modes (2 non-directional prediction modes and 65 directional prediction modes) in intra prediction. Solid arrows indicate H. A broken line arrow represents the added 32 directions, which represents the 33 directions defined in the H.265 / HEVC standard.

Note that a luminance block may be referred to in intra prediction of a chrominance block. That is, the chrominance component of the current block may be predicted based on the luminance component of the current block. Such intra prediction may be referred to as cross-component linear model (CCLM) prediction. The intra prediction mode (for example, referred to as a CCLM mode) of a chrominance block referencing such a luminance block may be added as one of the intra prediction modes of the chrominance 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 directions. Intra prediction with such correction is sometimes called position dependent intra prediction combination (PDPC). Information indicating the presence or absence of application of PDPC (for example, called a PDPC flag) is signaled, for example, at CU level. Note that the signaling of this information need not be limited to the CU level, but may be at other levels (eg, sequence level, picture level, slice level, tile level or CTU level).

[Inter prediction unit]
The inter prediction unit 126 performs inter prediction (also referred to as inter-frame prediction) of a current block with reference to a reference picture that is a reference picture stored in the frame memory 122 and that is different from the current picture. Generate a prediction signal). Inter prediction is performed in units of a current block or sub blocks (for example, 4 × 4 blocks) in the current block. For example, the inter prediction unit 126 performs motion estimation on the current block or sub block in the reference picture. 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 the 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 to signal the motion vector. That is, the difference between the motion vector and the predicted motion vector may be signaled.

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

In such OBMC mode, information indicating the size of sub-blocks 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, called an OBMC flag) is signaled at the CU level. Note that the level of signaling of these pieces of information need not be limited to the sequence level and the CU level, and may be other levels (eg, picture level, slice level, tile level, CTU level or subblock level) Good.

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

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

Next, the motion vector (MV_L) of the encoded left adjacent block is applied to the current block to obtain a predicted image (Pred_L), and the predicted image and Pred_L are weighted and superimposed. Perform the first correction of the image.

Similarly, the motion vector (MV_U) of the encoded upper adjacent block is applied to the coding target block to obtain a predicted image (Pred_U), and the predicted image subjected to the first correction and the Pred_U are weighted. A second correction of the predicted image is performed by adding and superposing, and this is made a final predicted image.

Although the two-step correction method using the left adjacent block and the upper adjacent block has been described here, the right adjacent block and the lower adjacent block may be used to perform correction more than two steps. It is possible.

The area to be superimposed may not be the pixel area of the entire block, but only a partial area near the block boundary.

Although the predicted image correction processing from one reference picture has been described here, 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 The final predicted image is obtained by further superimposing the obtained predicted images.

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

The motion information may be derived on the decoding device side without being signalized. For example, H. The merge mode defined in the H.265 / HEVC standard may be used. Also, for example, 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 estimation is performed on the decoding device side will be described. The mode in which motion estimation is performed on the side of the decoding apparatus may be referred to as a pattern matched motion vector derivation (PMMVD) mode or a frame rate up-conversion (FRUC) mode.

An example of the FRUC process is shown in FIG. 5D. First, referring to motion vectors of encoded blocks spatially or temporally adjacent to the current block, a plurality of candidate lists (which may be common to the merge list) each having a predicted motion vector are generated Be done. Next, the best candidate MV is selected from among the plurality of candidate MVs registered in the candidate list. For example, an 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 derived as it is as the motion vector for the current block. Also, for example, a motion vector for the current block may be derived by performing pattern matching in a peripheral region of a position in the reference picture corresponding to the selected candidate motion vector. That is, the search is performed on the area around the best candidate MV by the same method, and if there is an MV for which the evaluation value is good, the best candidate MV is updated to the MV and the current block is updated. It may be used as the final MV. In addition, it is also possible to set it as the structure which does not implement the said process.

When processing is performed in units of subblocks, the same processing may be performed.

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

As pattern matching, first pattern matching or 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, which are along 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 calculation of the evaluation value of the candidate 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, among pairs of two blocks in two reference pictures (Ref0, Ref1) which are two blocks along the motion trajectory of the current block (Cur block), Two motion vectors (MV0, MV1) are derived by searching for the most matching pair. Specifically, for the current block, a reconstructed image at a designated position in the first encoded reference picture (Ref 0) designated by the candidate MV, and a symmetric MV obtained by scaling the candidate MV at a display time interval. The difference with the reconstructed image at the specified position in the second coded reference picture (Ref 1) specified in step is derived, and the evaluation value is calculated using the obtained difference value. The candidate MV with the best evaluation value among the plurality of candidate MVs may be selected as the final MV.

Under the assumption of continuous motion trajectory, motion vectors (MV0, MV1) pointing to two reference blocks are the temporal distance 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, in the first pattern matching, the 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 (eg, upper and / or left adjacent blocks)) 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 area for calculating the evaluation value of the candidate described above.

FIG. 7 is a diagram for explaining an example of pattern matching (template matching) between a template in a current picture and a block in a reference picture. As shown in FIG. 7, in the second pattern matching, the current block (Cur Pic) is searched for in the reference picture (Ref 0) for a block that most closely matches a block adjacent to the current block (Cur block). Motion vectors are derived. Specifically, for the current block, the reconstructed image of the left adjacent region and / or the upper adjacent encoded region and the encoded reference picture (Ref 0) specified by the candidate MV are equivalent to each other. When the difference between the position and the reconstructed image is derived, the evaluation value is calculated using the obtained difference value, and the candidate MV having the best evaluation value among the plurality of candidate MVs is selected as the best candidate MV Good.

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

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

FIG. 8 is a diagram for explaining a model assuming uniform linear motion. In FIG. 8, (v _x , v _y ) indicate velocity vectors, and τ ₀ and τ ₁ indicate the time between the current picture (Cur Pic) and two reference pictures (Ref ₀ and Ref ₁ ), respectively. Indicate 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 uniform linear motion of the velocity vector (v _x , v _y ), (MV _x ₀ , MV y ₀ ) and (MV _x ₁ , MV y ₁ ) respectively represent (v _x τ ₀ , v _y τ ₀ ) and (-v _x τ ₁ , -v _y τ ₁ ), 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. The optical flow equation is: (i) the time derivative of the luminance value, (ii) the product of the horizontal velocity and the horizontal component of the spatial gradient of the reference image, and (iii) the vertical velocity and the spatial gradient of the reference image Indicates that the product of the vertical components of and the sum of is equal to zero. Based on the combination of the optical flow equation and Hermite interpolation, a motion vector in units of blocks obtained from a merge list or the like is corrected in units of pixels.

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 a model assuming uniform linear motion. For example, motion vectors may be derived on a subblock basis based on motion vectors of a plurality of adjacent blocks.

Here, a mode for deriving a motion vector in units of sub blocks based on motion vectors of a plurality of adjacent blocks will be described. This mode is sometimes referred to as affine motion compensation prediction mode.

FIG. 9A is a diagram for describing 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 sixteen 4 × 4 subblocks. 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 subblock Be 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 according to the following equation (2).

Here, x and y indicate the horizontal position and the vertical position of the sub block, respectively, and w indicates a predetermined weighting factor.

In such an affine motion compensation prediction mode, the derivation method of the motion vector of the upper left and upper right control points may include several different modes. Information indicating such an affine motion compensation prediction mode (for example, called an affine flag) is signaled at the CU level. Note that the signaling of the information indicating this affine motion compensation prediction mode need not be limited to the CU level, and other levels (eg, sequence level, picture level, slice level, tile level, CTU level or subblock level) ) May be.

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

Here, an example in which the motion vector of the current picture to be encoded is derived by the merge mode will be described. FIG. 9B is a diagram for describing an overview of motion vector derivation processing in the merge mode.

First, a predicted MV list in which candidates for predicted MV are registered is generated. As the prediction MV candidate, the position of the coding target block in the coded reference picture, which is the MV of the plurality of coded blocks located in the spatial periphery of the coding target block, is projected Temporally adjacent prediction MV which is an MV possessed by a nearby block, joint prediction MV which is an MV generated by combining spatially adjacent prediction MV and MVs of temporally adjacent prediction MV, and zero prediction MV whose value is MV, etc. There is.

Next, one prediction MV is selected from among the plurality of prediction MVs registered in the prediction MV list, and it is determined as the MV of the current block.

Furthermore, in the variable-length coding unit, merge_idx, which is a signal indicating which prediction MV has been selected, is described in the stream and encoded.

Note that the prediction MVs registered in the prediction MV list described in FIG. 9B are an example, and the number is different from the number in the drawing, or the configuration does not include some types of the prediction MV in the drawing, It may have a configuration in which prediction MVs other than the type of prediction MV in the drawing are added.

The final MV may be determined by performing the DMVR process described later using the MV of the coding target block derived in the merge mode.

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

FIG. 9C is a conceptual diagram for describing an overview of DMVR processing.

First, with the optimum MVP set as the processing target block as a candidate MV, according to the candidate MV, a first reference picture which is a processed picture in the L0 direction and a second reference picture which is a processed picture in the L1 direction To generate a template by averaging each reference pixel.

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

The outline of the process described here is basically common to the encoding apparatus and the decoding apparatus.

Note that even if the process is not a process described here, another process may be used as long as the process can search for the periphery of the candidate MV and derive a final MV.

Here, a mode in which a predicted image is generated using LIC processing will be described.

FIG. 9D is a diagram for describing 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 current block to be coded is derived from a reference picture which is a coded picture.

Next, for the block to be encoded, reference is made using the luminance pixel values of the left adjacent and upper adjacent encoded peripheral reference areas and the luminance pixel values at equivalent positions 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.

By performing luminance correction processing on a reference image in a reference picture designated by MV using the luminance correction parameter, a predicted image for a block to be encoded is generated.

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

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

As a method of determining whether to apply the LIC process, for example, there is a method using lic_flag which is a signal indicating whether to apply the LIC process. As a specific example, in the encoding apparatus, it is determined whether or not the encoding target block belongs to the area in which the luminance change occurs, and when it belongs to the area in which the luminance change occurs, as lic_flag A value of 1 is set and encoding is performed by applying LIC processing, and when not belonging to an area where a luminance change occurs, a value of 0 is set as lic_flag and encoding is performed without applying the LIC processing. . On the other hand, the decoding apparatus decodes lic_flag described in the stream to switch whether to apply the LIC processing according to the value and performs decoding.

As another method of determining whether to apply the LIC process, for example, there is also a method of determining according to whether or not the LIC process is applied to the peripheral block. As a specific example, when the encoding target block is in merge mode, whether or not the surrounding encoded blocks selected in the derivation of the MV in merge mode processing are encoded by applying LIC processing According to the result, whether to apply the LIC process is switched to perform encoding. In the case of this example, the processing in the decoding is completely the same.

[Overview of Decryption Device]
Next, an outline of a decoding apparatus capable of decoding the coded signal (coded bit stream) output from the above coding 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 a moving image / image in units of blocks.

As shown in FIG. 10, the decoding apparatus 200 includes an entropy decoding unit 202, an inverse quantization unit 204, an inverse conversion unit 206, an addition unit 208, a block memory 210, a loop filter unit 212, and a frame memory 214. , 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 processor executes the software program stored in the memory, the processor determines whether the entropy decoding unit 202, the inverse quantization unit 204, the inverse conversion unit 206, the addition unit 208, the loop filter unit 212, the intra prediction unit 216 functions as an inter prediction unit 218 and a prediction control unit 220. In addition, the decoding apparatus 200 is a dedicated unit corresponding to the entropy decoding unit 202, the inverse quantization unit 204, the inverse conversion 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. And one or more electronic circuits.

Each component included in the decoding device 200 will be described below.

[Entropy decoder]
The entropy decoding unit 202 entropy decodes the coded bit stream. Specifically, the entropy decoding unit 202 performs arithmetic decoding, for example, from a coded bit stream to a binary signal. Then, the entropy decoding unit 202 debinarizes the binary signal. Thereby, the entropy decoding unit 202 outputs the quantization coefficient to the dequantization unit 204 in block units.

[Inverse quantization unit]
The inverse quantization unit 204 inversely quantizes the quantization coefficient of the block to be decoded (hereinafter referred to as a current block), which is an input from the entropy decoding unit 202. Specifically, the dequantization part 204 dequantizes the said quantization coefficient about each of the quantization coefficient of a current block based on the quantization parameter corresponding to the said quantization coefficient. Then, the dequantization unit 204 outputs the dequantized quantization coefficient (that is, transform coefficient) of the current block to the inverse transformation unit 206.

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

For example, when the information deciphered from the coded bit stream indicates that the EMT or AMT is applied (for example, the AMT flag is true), the inverse transform unit 206 determines the current block based on the deciphered transformation type information. Inverse transform coefficients of

Also, for example, when the information deciphered from the coded bit stream indicates that the NSST is to be applied, the inverse transform unit 206 applies inverse retransformation to the transform coefficients.

[Adder]
The addition unit 208 adds the prediction error, which is the input from the inverse conversion unit 206, and the prediction sample, which is the input from the prediction control unit 220, to reconstruct the current block. Then, the adding unit 208 outputs the reconstructed 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 within a picture to be decoded (hereinafter referred to as a current picture) which is a block referred to in intra prediction. 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 and a display device or the like.

If the information indicating on / off of ALF read from the encoded bit stream indicates that ALF is 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 may be referred to as a frame buffer. Specifically, the frame memory 214 stores the reconstructed block filtered by the loop filter unit 212.

[Intra prediction unit]
The intra prediction unit 216 refers to a block in the current picture stored in the block memory 210 to perform intra prediction based on the intra prediction mode read from the coded bit stream, thereby generating a prediction signal (intra prediction Signal). Specifically, the intra prediction unit 216 generates an intra prediction signal by performing intra prediction with reference to samples (for example, luminance value, color difference value) of a block adjacent to the current block, and performs prediction control on the intra prediction signal. Output to unit 220.

When the intra prediction mode that refers to the luminance block is selected in the intra prediction of the chrominance block, the intra prediction unit 216 may predict the chrominance component of the current block based on the luminance component of the current block. .

Also, when the information read from the coded bit stream indicates the application of PDPC, the intra prediction unit 216 corrects the pixel value after intra prediction based on the gradient of reference pixels in the horizontal / vertical directions.

[Inter prediction unit]
The inter prediction unit 218 predicts the current block with reference to the reference picture stored in the frame memory 214. The prediction is performed in units of the current block or subblocks (for example, 4 × 4 blocks) 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 coded bit stream, and generates an inter prediction signal. It is output to the prediction control unit 220.

When the information deciphered from the coded bit stream indicates that the OBMC mode is applied, the inter prediction unit 218 determines not only the motion information of the current block obtained by the motion search but also the motion information of the adjacent block. Use to generate an inter prediction signal.

Also, in the case where the information deciphered from the coded bit stream indicates that the FRUC mode is applied, the inter prediction unit 218 is configured to follow the method of pattern matching deciphered from the coded stream (bilateral matching or template matching). 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 uniform linear motion. Also, in the case where the information deciphered from the coded bit stream indicates that the affine motion compensation prediction mode is applied, the inter prediction unit 218 performs motion vectors in units of sub blocks based on motion vectors of a plurality of adjacent blocks. Derive

[Prediction control unit]
The prediction control unit 220 selects one of the intra prediction signal and the inter prediction signal, and outputs the selected signal to the addition unit 208 as a prediction signal.

[First example of inter prediction processing]
FIG. 11 is a flowchart of a first example of inter prediction processing in the encoding device 100. Although the operation of the inter prediction unit 126 included in the coding apparatus 100 will be mainly described below, the operation of the inter prediction unit 218 included in the decoding apparatus 200 is also the same.

The inter prediction unit 126 selects, from a plurality of modes (FRUC mode, normal mode, merge mode, etc.), an inter prediction mode to be used for a target block which is a block to be encoded or to be decoded. The inter prediction unit 126 derives a motion vector (MV) using the selected inter prediction mode.

When a mode other than FRUC is selected, the inter prediction unit 126 derives a motion vector, and encodes information on the derived motion vector into a stream. The inter prediction unit 126 generates a predicted image by performing motion compensation using the derived motion vector.

On the other hand, when the FRUC mode is selected, the inter prediction unit 126 searches for the image of the processed area without encoding the information on the motion vector into the stream using the method described with reference to FIGS. 6 and 7. To derive motion vectors.

In the first example, the inter prediction unit 126 first determines, for each CTU that is a basic division unit of a picture, a search range for limiting the range of the processed region to be referred to in the derivation of the motion vector of FRUC processing. (S201).

Next, the inter prediction unit 126 performs inter prediction processing using the FRUC mode or another mode for each CU that is a processing basic unit belonging to the CTU.

When the FRUC mode is used (Yes in S202), the inter prediction unit 126 first refers to the motion vector of the processed CU around the target CU that is the CU to be encoded or decoded and refers to the candidate motion vector list. It generates (S203).

Next, the inter prediction unit 126 excludes, from among the plurality of candidate motion vectors registered in the candidate motion vector list, candidate motion vectors that reference the outside of the search range determined in step S201 (S204).

Next, the inter prediction unit 126 refers to the processed region using the template matching scheme or the bilateral matching scheme for each of the remaining candidate motion vectors excluded among the plurality of candidate motion vectors registered in the candidate motion vector list. And evaluate the cost. Then, the inter prediction unit 126 selects a candidate motion vector with the smallest cost (S205). Furthermore, the inter prediction unit 126 searches for a peripheral region of the selected candidate motion vector to derive a final motion vector (S206).

Next, the inter prediction unit 126 generates a predicted image by performing motion compensation using the derived motion vector (S207).

As described above, by excluding candidate motion vectors that reference the outside of the search range from the evaluation target, the region necessary for the reference is limited to the region within the search range. Therefore, it is possible to limit the amount of access to the memory storing the image of the processed area. Furthermore, since the number of candidate motion vectors to be evaluated is reduced, the amount of processing can be suppressed.

On the other hand, when the inter prediction mode other than the FRUC mode is used (No in S202), the inter prediction unit 126 derives a motion vector according to the inter prediction mode, and encodes information on the derived motion vector into a stream (S208). ). Next, the inter prediction unit 126 generates a prediction image by performing motion compensation using the derived motion vector (S209).

In the example illustrated in FIG. 11, the inter prediction unit 126 determines the search range in CTU units, but may not be in CTU units, and for example, determines the search range in units of collecting a plurality of CUs It is also good.

Further, in the example shown in FIG. 11, the processing in units of CUs has been described, but the same applies to the case where processing in units of sub-blocks obtained by further dividing CUs is performed.

Further, the process flow illustrated in FIG. 11 is an example, and a part of the processes described may be removed or a process not described may be added.

In addition, the inter prediction processing in the decoding device 200 is also basically the same as the processing flow described here, with the difference between encoding a signal necessary for processing into a stream or decoding from a stream.

FIG. 12 is a diagram for describing a process of excluding a candidate motion vector that refers to the outside of the search range from the evaluation target in step S204 described with reference to FIG.

In the example shown in FIG. 12, the target CTU which is a CTU to be encoded or to be decoded is composed of three CUs CU0, CU1, and CU2. CU0 and CU2 are processed in FRUC mode, and CU1 is processed in modes other than FRUC.

CU0 has CU0_MV0 and CU0_MV1 as candidate motion vectors in the FRUC mode. CU0_MV0 is set as an evaluation target in order to refer to the search range. On the other hand, CU0_MV1 is excluded from the evaluation targets because it refers to the outside of the search range.

CU2 has CU2_MV0 and CU2_MV1 as candidate motion vectors in the FRUC mode. CU2_MV0 is set as an evaluation target to refer to the search range. On the other hand, CU2_MV1 is excluded from the evaluation targets because it refers to the outside of the search range.

On the other hand, since a mode other than FRUC is used for CU1, a prediction image is generated using the reference area indicated by CU1_MV0 regardless of the above-described restriction processing. That is, when a mode other than FRUC is used, candidate motion vectors that reference the outside of the search range are used.

As described above, by limiting the evaluation target of the candidate motion vector of FRUC according to the search range, the inter prediction unit 126 uses the pixels within the search range as the FRUC even if the number of candidate motion vectors is large. It can process. Therefore, it is possible to limit the amount of access to the memory storing the image of the processed area. Furthermore, since the number of candidate motion vectors to be evaluated is reduced, the amount of processing can be suppressed.

In addition, in modes other than FRUC, since the reference region indicated by the derived motion vector is limited, the amount of access to the memory does not increase extremely.

Note that the inter prediction unit 126 determines whether or not the block position itself indicated by each candidate motion vector falls within the search range, as a method of determining whether each candidate motion vector of FRUC is within the search range. Not only the block position indicated by the candidate motion vector but also one or more regions used in the inter prediction process (FRUC process) may be determined within the search range. Here, the one or more regions used for inter prediction processing are the peripheral region necessary for template matching, the application region of filter taps necessary for pixel acquisition of motion vector positions of decimal pixels, and cost optimum It is an area or the like for a peripheral search to be performed after selecting candidate motion vectors that become.

In addition, the one or more areas may include a reference area that is required in other processes (MC process, BIO process, OBMC process, etc.) related to the predicted image generation after performing the FRUC process.

Also, if the reference area required for processing is outside the above search range in other processing (MC processing, BIO processing, OBMC processing, LIC processing, etc.) related to predicted image generation after performing the FRUC processing, The inter prediction unit 126 may generate a prediction image without performing the other processing.

In the above description, the process for one reference picture is described, but the process for a plurality of reference pictures is the same.

Also, the processing described here is common to the inter prediction processing in the encoding device 100 and the inter prediction processing in the decoding device 200.

[Method of specifying search range in first example of inter prediction processing]
FIG. 13 is a diagram for explaining the search range determined in step S201 described with reference to FIG.

The inter prediction unit 126 determines the search range from information including the reference pictures that can be referred to, the size (vertical width × horizontal width) of the search area in each reference picture, and the center position of the search area in each reference picture. .

In the example shown in FIG. 13, referenceable reference pictures are reference picture 1 and reference picture 2, the vertical width of the search area in reference picture 1 is height1, horizontal width is width1, and the center position is center1. is there. The vertical width of the search area in the reference picture 2 is height2, the horizontal width is width2, and the center position is center2.

The size of the search area may be designated for each reference picture. Thus, for example, the search area of reference picture 2 that is temporally far from the target picture that is the picture to be encoded or decoded is made larger than the search area of reference picture 1 that is temporally close to the target picture. It is possible to improve the followability to a moving area in which the variation increases with the lapse of time.

Also, the size of the search area may be designated as a common size for all reference pictures. This eliminates the need to encode information on the size of the search area for each reference picture, thereby making it possible to suppress the code amount related to the search range information.

Further, the size of the search area may be switched and designated in accordance with the number of reference pictures that can be referred to. Thus, for example, when the number of reference pictures that can be referred to is small, it is possible to search a wider range by enlarging the search area. When the number of reference pictures that can be referred to is large, the amount of access to the memory can be suppressed by reducing the search area.

Information on the number of referable reference pictures and the upper limit of the size of the search area, or information on the upper limit of the sum of sizes of the search areas in all reference pictures is a stream to be encoded or decoded. The encoding apparatus 100 defines the number of reference pictures and the size of the search area or the sum of the sizes of the search areas to be less than or equal to the specified upper limit. The size of the search area may be set to For example, at a level assuming a decoding apparatus with low processing power, the upper limit of the sum of the sizes of the search areas is defined as a small value. This makes it possible to guarantee that the decoder can decode the stream even at a low memory transfer rate.

The center position is indicated by how much the position of the search area in each reference picture is shifted with respect to the position of the target CTU in the target picture. In the example of FIG. 13, the center position is specified based on the center position of the target CTU, but the center position may be specified based on, for example, the upper left position.

As a method of specifying the center position of the search area in each reference picture, (1) a method of deriving and specifying a center position shift amount for each target CTU, (2) center position shift common to all CTUs in the target picture There are two ways to derive and specify the quantity.

FIG. 14 is a diagram for describing a method of deriving the center position shift amount of the search area described in FIG. 13 for each target CTU.

In FIG. 14, the inter prediction unit 126 is configured such that a processed CTU (upper-CTU) adjacent to the upper side with respect to the target CTU, a processed CTU (left-CTU) adjacent to the left with respect to the target CTU, and a processed picture. Referring to the processed CTU (Col-CTU) at the same position as the target CTU in, and using the motion vector values of the CUs belonging to each processed CTU, the center position shift amount of the search area of the target CTU is derived There is.

Specifically, the inter prediction unit 126 calculates an average value of motion vectors of all CUs belonging to the processed CTU to be referred to as a center position shift amount. Alternatively, the inter prediction unit 126 derives an average motion vector value for each processed CTU to be referenced, selects one of a plurality of derived average motion vector values, and uses the selected average motion vector value as a center position shift amount calculate.

Note that, as in the example illustrated in FIG. 13, when there are a plurality of reference pictures that can be referred to, the inter prediction unit 126 determines a motion vector of a CU that refers to the target reference picture among the CUs belonging to the processed CTU. The center position shift amount may be derived using

As described above, the inter prediction unit 126 locally moves the information without encoding the information on the center position in the stream by deriving the center position shift amount with reference to the processed CTUs in the periphery for each target CTU. It is possible to specify an optimal search area even for images of different types. This makes it possible to improve coding performance without increasing the code amount.

Although FIG. 14 illustrates an example of deriving the center position shift amount with reference to three processed CTUs, Upper-CTU, Left-CTU, and Col-CTU, the processed CTU to be referred is limited to this. Absent. For example, the inter prediction unit 126 may use any one or two of the three processed CTUs described above, or may use a processed CTU other than the three processed CTUs. For example, the inter prediction unit 126 may derive the center position shift amount without referring to the Left-CTU whose processing order is immediately before the target CTU. This enables the inter prediction unit 126 to start memory transfer of reference pixels in the search area for the target CTU without waiting for the completion of the process of deriving motion vectors of the respective CUs belonging to the Left-CTU. . This makes it possible to shorten the waiting time for the completion of memory transfer.

Note that the processing described here is common to both the inter prediction processing in the encoding device 100 and the inter prediction processing in the decoding device 200.

Also, the encoding apparatus 100 may directly determine the center position shift amount of the target CTU without referring to the processed CTUs in the periphery, and encode information on the center position for each target CTU in the stream. As a result, although the code amount is increased, a more accurate search area can be specified, which makes it possible to improve the coding performance. In addition, since the decoding apparatus 200 can directly acquire information about the center position of each target CTU from the stream, the processing can be simplified.

FIG. 15 is a diagram for describing a method of deriving the center position shift amount of the search area described in FIG. 13 as a value common to all CTUs in the target picture.

In FIG. 15, the inter prediction unit 126 derives a common center position shift amount for all CTUs in the target picture, with reference to the motion vector of the entire processed picture.

Specifically, the inter prediction unit 126 aggregates statistics of motion vectors of a plurality of CUs of processed pictures, and estimates motion vectors of the entire target picture using the aggregated statistics. Then, the inter prediction unit 126 sets the estimated motion vector value to each CTU as the center position shift amount. For example, the inter prediction unit 126 uses, as a statistic, an average motion vector derived from motion vectors of all CUs in the processed picture. Thus, the inter prediction unit 126 can derive the center position shift amount using the average motion vector as it is as the estimated motion vector value of the entire target picture. Alternatively, the inter prediction unit 126 classifies motion vectors of the processed picture into a plurality of classes as statistics and uses an average motion vector derived for each class. Thereby, the inter prediction unit 126 can select an optimal one from among the plurality of derived average motion vectors, and can use the selected average motion vector as an estimated motion vector value of the entire target picture. Therefore, the inter prediction unit 126 can derive an optimal center position shift amount.

When there are a plurality of reference pictures that can be referred to as in the example shown in FIG. 13, the inter prediction unit 126 scales the estimated motion vector value of the entire target picture according to the time distance to the reference picture. The center position shift amount may be derived using the above value. Alternatively, the inter prediction unit 126 may select an optimal average motion vector for each reference picture from a plurality of average motion vectors obtained for each class, and derive the center position shift amount using the selected average motion vector. .

As described above, the inter prediction unit 126 may derive a central position shift amount common to all CTUs in the target picture, and encode information on the central position into a stream on a picture basis. Therefore, it becomes possible to specify the center position without increasing the code amount. In addition, since the process of deriving the center position on a CTU basis is unnecessary, the center position can be specified without increasing the amount of processing.

Although FIG. 15 illustrates an example in which a motion position is estimated for the entire picture and a common center position shift amount is derived for all CTUs in the target picture, the inter prediction unit 126 has a plurality of pictures. A motion vector may be estimated for each slice divided into regions, and a common center position shift amount may be derived for all CTUs in the target slice. As a result, it becomes possible to specify an optimum search area even for an image whose motion is different for each slice.

Although FIG. 15 illustrates an example in which the center position shift amount is derived using the information of the motion vector of the processed picture, the inter prediction unit 126 is not the object of the motion picture of the processed picture. The motion of the entire target picture may be directly estimated using the input image of the picture, and the center position shift amount may be derived using the estimated motion. As a result, it is possible to estimate the motion vector of the entire target picture more accurately although the amount of processing is increased. Furthermore, it becomes possible to specify an optimal search area.

Also, the value 0 (the same position as the target CTU) may always be used as the center position shift amount. Thus, the inter prediction unit 126 can derive the center position without performing any processing. Furthermore, the inter prediction unit 126 can perform processing without stream encoding information on the center position.

Note that the process described here is a process in the inter prediction process in the encoding apparatus 100, but the decoding apparatus 200 acquires information on the center position by decoding the stream generated by the described process.

[Memory access method of the first example of inter prediction processing]
FIGS. 16A and 16B are diagrams for explaining the data transfer method from the memory storing the image of the processed area in the first example of the inter prediction processing in encoding apparatus 100.

As described with reference to FIG. 12, in the first example, transfer of reference pixels in the search range for reference in the FRUC mode and transfer of reference pixels for reference in the modes other than FRUC are necessary. . In the example shown in FIGS. 16A and 16B, the transfer of the reference pixel in the search range for reference in the FRUC mode is completed before the processing of the target CTU starts, and the reference pixel for reference in a mode other than FRUC. The transfer is performed when the motion vector of each CU belonging to the target CTU is determined.

In the example illustrated in FIG. 16A, the center position shift amount necessary to determine the search range for CTU1 is derived using the motion vector of CTU0 immediately before in processing order. For example, the case of deriving the center position shift amount using the Left-CTU motion vector described in FIG. 14 corresponds to this. In the process of CTU0, transfer of reference pixels in the search range for CTU1 is started when the motion vectors of all the CUs belonging to CTU0 are determined. As a result, the transfer process may not be completed before the CTU0 process is completed, and the CTU1 process may be kept waiting. If the transfer rate is fast enough, or if the processing time that can be allocated to process one CTU is long enough, the latency can be small, but otherwise the latency will be large and the There is a possibility that the processing of the target picture can not be completed within the required processing time.

On the other hand, in the example shown in FIG. 16B, the center position shift amount necessary to determine the search range for CTU1 is derived without using the motion vector of CTU0 immediately before in the processing order. For example, in the case of deriving the center position shift amount without using the Left-CTU motion vector described in FIG. 14 or in the case of deriving the common center position shift amount in all CTUs in the target picture described in FIG. Is equivalent to this. Since transfer of reference pixels in the search range for CTU1 can be started independently of the processing of CTU0, transfer processing can be started at an early point. As a result, the transfer process can be completed before the CTU 0 process is completed, so that the CTU 1 process can be started without waiting time. This allows the latency to be reduced even if the transfer rate is not fast enough, or if the processing time that can be allocated to the processing of one CTU is not long enough. Therefore, there is a high possibility that the processing of the target picture can be completed within the allocated processing time.

Note that the data transfer method described here is an example, and part of the described processing may be removed or processing not described may be added.

Also, the data transfer method of the inter prediction process in the decoding device 200 is basically the same.

FIGS. 17A to 17C are diagrams for describing a pixel region which requires data transfer in transfer of reference pixels in a search range for CTU 1 described in the example shown in FIG.

FIG. 17A shows an example in the case of transferring all pixel areas of the search range of CTU1. In this example, since all pixel areas in the search range of CTU1 indicated by oblique lines are always transferred regardless of the pixel area transferred by CTU processed prior to CTU1, the transfer amount increases. On the other hand, since the required transfer amount is always constant, and control can be performed without considering pixel areas transferred by other CTUs, control related to data transfer can be simplified.

FIG. 17B shows an example in the case of transferring only a part of pixel regions in the search range of CTU1. In this example, among the search range of CTU1, a pixel area indicated by hatching not transferred by the CTU processed earlier than CTU1 is transferred. In the example shown in FIG. 17B, the required transfer amount can be reduced as compared with the example of FIG. 17A. On the other hand, it is necessary to have a mechanism for internally securing data transferred in each CTU for use in subsequent CTUs. Furthermore, since the amount of transfer required for each CTU changes due to the difference in the amount of shift of the central position of the search range of each CTU, control related to data transfer may be complicated.

FIG. 17C shows another example in the case of transferring only a part of pixel areas in the search range of CTU1. In the example of FIG. 17B, the transfer method assuming that the central position shift amount of the search range is different for each CTU has been described, but in the example of FIG. 17C, the central position shift amount of the search range of each CTU is common Is assumed. For example, the case where the central position shift amount common to all the CTUs in the target picture described in FIG. 15 is derived corresponds to this. Since the center position shift amount of the search range of each CTU is the same, whenever the target CTU advances one direction to the right, the pixel region indicated by the diagonal line corresponding to the CTU width at the right end of the search range is transferred. In the example shown in FIG. 17C, the required transfer amount can be reduced as compared to the example of FIG. 17A. Furthermore, since the transfer amount required for each CTU is always constant, control related to data transfer can be simplified.

[Variation of first example of inter prediction processing]
Note that the encoding apparatus 100 can refer to a reference header that can be referred to for determining the search range described in FIG. 13 and information on the size of the search area in each reference picture, the sequence header area of the target stream, the picture header area, The slice header area or the side information area may be encoded, and the decoding apparatus 200 may decode the above information from those areas.

For example, the encoding apparatus 100 may switch the number of reference pictures that can be referred to and the size of the search area according to the processing capability of the decoding apparatus 200 at the transmission destination of the stream. For example, when the processing capability of the decoding device 200 is high, the encoding device 100 sets a wide search range because the decoding device 200 can perform many processes in a fixed processing time, and the processing capability of the decoding device 200 If it is low, the decoding apparatus 200 may set a narrow search range because it can not perform many processes in a fixed processing time.

Also, the encoding apparatus 100 may switch the number of reference pictures that can be referred to and the size of the search area according to the profile or level information assigned to the target stream. For example, the encoding apparatus 100 sets a wide search range at a profile and a level assuming sufficient processing power of the decoding apparatus 200, and sets a narrow search range at a profile and a level assuming the processing capacity of the insufficient decoding apparatus 200. You may

Also, the encoding apparatus 100 may switch the number of reference pictures that can be referred to and the size of the search area according to the size of the target picture. For example, when the picture size is small, the encoding apparatus 100 sets a wide search range because the number of blocks to be processed is small and the processing time has a margin, and when the picture size is large, the number of blocks to be processed is large. A narrow search range may be set because there is no room for Or, conversely, if the picture size is small, the encoding apparatus 100 sets a narrow search range to suppress excessive variation of motion vectors, and if the picture size is large, it can search a wider range. A wide search range may be set.

Note that the referenceable reference pictures encoded in the stream and the information on the size of the search area in each reference picture may not be signals of information strictly indicating them, and may be coded as signals having other meanings. It may be For example, by directly associating the information with the profile and the level, the decoding device 200 can specify the information using a signal indicating the profile and the level.

[Other variations of the first example of inter prediction processing]
In the search range specification method of the first example of the inter prediction processing described in FIGS. 13 to 15, the search area is defined for each reference picture, but instead of the reference picture, the search area for each reference index You may define For example, by associating a plurality of reference indices with the same one reference picture, it becomes possible to set a plurality of search areas in the same one reference picture. This makes it possible to search a wider range of regions by using different reference indexes.

Also, the coding apparatus 100 uses the first method of deriving the center position shift amount of the search area described in FIG. 14 for each target CTU, and the center position shift amount of the search area described in FIG. A second method of deriving a value common to all CTUs may be switched on a picture basis. For example, the encoding apparatus 100 uses the first method when there are mixed regions that perform different movements in the screen, and in the case of a picture that performs the same movement in all the regions in the screen. Use the second method. This makes it possible to specify an appropriate search area without reducing the coding efficiency. In addition, the encoding apparatus 100 encodes information indicating which of the first method and the second method is to be used in the picture header area, slice header area or auxiliary information area, and the decoding apparatus 200 The above information may be decoded and acquired from those areas.

[Effect of the first example of inter prediction processing]
With the configuration described with reference to FIGS. 11 to 17C, when processing the target CTU using the FRUC mode, the amount of access to the memory storing the image of the processed area can be limited, and thus the data transfer is involved. Processing time can be suppressed. Furthermore, since the number of FRUC candidate motion vectors to be evaluated is reduced, the amount of processing related to the FRUC processing can be suppressed. As a result, there is a high possibility that the processing of all the blocks can be completed within the processing time allocated to one picture even in the coding apparatus 100 and the decoding apparatus 200 with low processing performance.

[Second example of inter prediction processing]
FIG. 18 is a flowchart of a second example of inter prediction processing in the encoding device 100. The process shown in FIG. 18 is different from the process of the first example shown in FIG. 11 in that step S210 is added.

In the first example, the coding apparatus 100 excludes candidate motion vectors of the FRUC process that refers to the outside of the search range determined in step S201 from the evaluation targets, in the FRUC mode (S204). On the other hand, in the second example, the encoding apparatus 100 excludes a mode that refers to the outside of the search range determined in step S201 even in modes other than FRUC (S210).

As a result, among all the inter prediction modes including the FRUC mode, the inter prediction mode that refers to the pixels within the search range can be used. As a result, since the references by all the CUs belonging to the target CTU are limited to the area within the search range, it is possible to further limit the access amount to the memory storing the image of the processed area.

In the example illustrated in FIG. 18, although the encoding device 100 determines the search range in CTU units, it may not be in CTU units, and for example, the search range is determined in units of collecting a plurality of CUs It is also good.

Further, in the example shown in FIG. 18, the processing in units of CUs has been described, but the same applies to the case where processing in units of subblocks obtained by further dividing CUs is performed.

In addition, the process flow illustrated in FIG. 18 is an example, and part of the processes described may be removed or processes not described may be added.

Moreover, although the process in the inter prediction process in the encoding apparatus 100 was demonstrated here, also in the decoding apparatus 200, when a FRUC mode is used, the process similar to the encoding apparatus 100 is performed. When a mode other than FRUC is used, the decoding device 200 decodes the stream generated by the above-described processing, whereby the decoding processing is performed without using the inter prediction mode that refers to the outside of the search range automatically. It will be.

FIG. 19 is a diagram for describing a process of excluding a candidate motion vector of FRUC which refers to the outside of the search range and modes other than FRUC in steps S204 and S210 described in FIG. 18 from evaluation targets.

The difference from the processing in the first example described in FIG. 12 is that in CU1 where modes other than FRUC are used, the use of the mode in CU1 is prohibited because the area indicated by CU1_MV0 is out of the search range It is. As a result, the encoding apparatus 100 processes CU1 using an inter prediction mode or an intra prediction mode other than the mode.

Thus, in addition to restricting the candidate motion vectors of FRUC according to the search range, by restricting modes other than FRUC according to the search range, reference by all CUs belonging to the target CTU is restricted to the region within the search range. Ru. This makes it possible to further limit the amount of access to the memory storing the image of the processed area.

In addition, the encoding apparatus 100 only determines whether the block position itself indicated by the motion vector is within the search range, as a method of determining whether the motion vector in any mode other than FRUC is within the search range. Search range for both the block position indicated by the motion vector and the reference area required for other processing related to predicted image generation (ME processing, MC processing, BIO processing, OBMC processing, LIC processing, DMVR processing, etc.) It may be determined whether or not it is stored inside.

Also, in the case of other processing (ME processing, MC processing, BIO processing, OBMC processing, LIC processing, DMVR processing, etc.) related to predicted image generation, encoding is performed when the reference region required for processing is out of the search range The apparatus 100 may generate a prediction image without performing the other processing.

Moreover, although the process which excludes the said inter prediction mode from evaluation object when the motion vector of inter prediction modes other than FRUC was out of the search range was illustrated here, it is not limited to this example. For example, the coding apparatus 100 excludes a motion vector indicating an area outside the search range in the inter prediction mode from the evaluation target, and performs prediction processing in the inter prediction mode using the motion vector indicating the area within the search range. You may go.

[Memory access method of the second example of inter prediction processing]
FIG. 20A and FIG. 20B are diagrams for explaining the data transfer method from the memory storing the image of the processed area in the second example of the inter prediction processing in encoding apparatus 100.

The data transfer method shown in FIGS. 20A and 20B is different from the data transfer method in the first example described in FIGS. 16A and 16B in that the transfer of reference pixels for reference in modes other than FRUC is lost. Is different.

As described with reference to FIG. 19, in the second example, since the pixel area outside the search range is not referred to in both the FRUC mode and the modes other than FRUC, transfer of pixels outside the search range is unnecessary. This eliminates the waiting time generated for transfer of reference pixels for reference in modes other than FRUC. Therefore, even if the transfer rate is not fast enough, or the processing time that can be allocated to the processing of one CTU is not long enough, processing of the target picture can be completed within the allocated processing time. Sex is high.

[Variation of second example of inter prediction processing]
Note that, as described in step S210 illustrated in FIG. 18, the encoding apparatus 100 may use information indicating whether the stream has been encoded excluding the inter prediction mode that refers to the outside of the search range. The decoding apparatus 200 may encode the sequence header area, the picture header area, the slice header area, or the auxiliary information area, and decode and acquire the information from those areas.

For example, the encoding apparatus 100 may switch whether to exclude the inter prediction mode according to the processing capability of the decoding apparatus 200 at the transmission destination of the stream. For example, when the processing capability of the decoding device 200 is high, the encoding device 100 performs encoding without excluding the inter prediction mode because the decoding device 200 can perform many processes in a fixed processing time, and performs decoding When the processing capability of the apparatus 200 is low, the decoding apparatus 200 may perform coding without the inter prediction mode because it can not perform many processes in a fixed processing time.

Also, the coding apparatus 100 may switch whether to exclude the inter prediction mode according to the profile or level information assigned to the target stream. For example, the encoding apparatus 100 performs encoding without excluding the inter prediction mode in profiles and levels assuming sufficient processing capacity of the decoding apparatus 200, and profiles and levels assuming insufficient processing capacity of the decoding apparatus 200. Then, coding may be performed excluding the inter prediction mode.

Also, the coding apparatus 100 may switch whether to exclude the inter prediction mode according to the size of the target picture. For example, when the picture size is small, the coding apparatus 100 performs coding without excluding the inter prediction mode because the number of blocks to be processed is small and the processing time has a margin, and performs processing when the picture size is large. Since the number of blocks is large and the processing time is not enough, coding may be performed excluding the inter prediction mode. Or conversely, if the picture size is small, the coding apparatus 100 performs coding by excluding the inter prediction mode in order to suppress excessive variation of motion vectors, and if the picture size is large, the coding is wider. The coding may be performed without excluding the inter prediction mode so that the range can be searched.

Note that the information indicating whether the stream is encoded by excluding the inter prediction mode that refers to the outside of the search range, which is encoded into the stream, is not a signal of information that indicates the stream strictly. And may be encoded as signals having other meanings. For example, by directly associating the information with the profile and the level, the decoding device 200 can specify the information using a signal indicating the profile and the level.

[Effect of the second example of inter prediction processing]
With the configuration described with reference to FIGS. 18 to 20B, the amount of access to the memory storing the image of the processed area can be limited in the processing of all CUs belonging to the target CTU. Can be suppressed. Furthermore, since the number of inter prediction modes to be evaluated is reduced, it is possible to suppress the amount of processing related to the inter prediction processing in the encoding device 100. As a result, there is a high possibility that the processing of all the blocks can be completed within the processing time allocated to one picture even in the coding apparatus 100 and the decoding apparatus 200 with low processing performance.

As described above, the encoding apparatus 100 according to the present embodiment sets a search range to be commonly used in the first processing unit (for example, CTU) (S201), and one or more included in the first processing unit. For the second processing unit using inter prediction among the second processing units (for example, CU), restrict reference to pixels outside the search range and perform encoding processing with reference to the pixels within the search range (S 204 or S210). Thus, the amount of access to the memory storing the image of the processed area can be limited, so that the processing time related to data transfer can be suppressed and the amount of processing can be reduced.

For example, the first processing unit may be a block unit configured of one or more second processing units, which is a basic division unit of a picture, or a predefined unit configured of one or more second processing units. It is a block unit of size.

For example, the coding apparatus 100 performs motion compensation processing using a motion vector assigned to an inter prediction mode to be selected among a plurality of inter prediction modes with respect to a target second processing unit included in the first processing unit. Then, the inter prediction mode that refers to the pixel outside the search range is excluded, one mode is selected from the inter prediction mode after the exclusion and the intra prediction mode, and the encoding process is performed using the selected mode.

For example, in the inter prediction mode exclusion (S210), the coding apparatus 100 is further out of the search range in another process related to predicted image generation applied to other than the motion compensation process in the inter prediction mode to be selected. Exclude inter prediction modes that require pixels.

For example, in the inter prediction mode to be selected, the encoding apparatus 100 is another process related to predicted image generation applied other than the motion compensation process, and there is another process requiring pixels outside the search range. In this case, the predicted image is generated without performing other processing.

For example, in the setting of the search range (S201), the encoding apparatus 100 includes information including a processed picture that can be referred to, the size of the search area in the processed picture, and the center position shift amount of the search area in the processed picture. Use to set the search range.

For example, the encoding apparatus 100 switches the size of the search area according to the number of referable processed pictures.

For example, the encoding apparatus 100 sets the size of the search area such that the sum of the search areas in the referenceable processed pictures is equal to or less than a specific value.

For example, the encoding apparatus 100 defines the upper limit value of the number of processable pictures that can be referred to and the size of the search area or the total sum of the search areas in association with the profile value or the level value. The encoding apparatus 100 sets the number of referable processed pictures and the size of the search area so as to be a value equal to or less than the upper limit value according to the profile value or the level value assigned to the target stream.

For example, in the sequence header area, information indicating that the encoding apparatus 100 has not selected the inter prediction mode requiring pixels outside the search range in all the second processing units included in the first processing unit, It is encoded into a picture header area, a slice header area or a side information area.

For example, the coding apparatus 100 switches whether to exclude the inter prediction mode that refers to the pixels outside the search range, according to the processing capability of the decoding apparatus 200.

For example, the encoding apparatus 100 switches whether to exclude an inter prediction mode that refers to a pixel outside the search range, according to the profile value or the level value assigned to the target stream.

For example, the coding apparatus 100 switches whether to exclude an inter prediction mode that refers to a pixel outside the search range, according to the size of the target picture.

For example, the center position shift amount of the search area is a shift amount between the position of the target first processing unit in the target picture and the position of the search area in the processed picture to be referenced.

For example, the encoding apparatus 100 derives the center position shift amount of the search area for each first processing unit.

For example, the encoding apparatus 100 is a motion assigned to the second processing unit included in the processed first processing unit located in the spatial or temporal periphery of the target first processing unit for the center position shift amount of the search region. Derivate using a vector.

For example, the processed first processing unit is a processed first processing unit other than the first processing unit whose processing order is immediately before the target first processing unit.

For example, the encoding apparatus 100 sets a common value to all first processing units included in the target picture or target slice as the center position shift amount of the search area. Encoding apparatus 100 encodes information for specifying a common value into a picture header area or a slice header area.

For example, the encoding apparatus 100 sets the common value to a value at which the shift of the center position is zero.

For example, the encoding apparatus 100 derives a common value using statistics of a plurality of motion vectors derived in a plurality of second processing units included in a processed picture.

For example, when the position of the search range is specified, the encoding device 100 refers to the reference pixel data of the search range set for the target first processing unit from the memory storing the image data of the processed picture. The transfer of the target first processing unit is started after the transfer is completed.

For example, the encoding apparatus 100 is set for the target first processing unit from the memory storing the image data of the processed picture without waiting for the processing of the first processing unit whose processing order is immediately before. Transfer of reference pixel data in the search range is started.

For example, in the reference pixel data of the search range set for the target first processing unit, the encoding device 100 overlaps the search range set for the already processed first processing unit. The reference pixel data is transferred from the memory except for the reference pixel data.

For example, the encoding device 100 restricts reference to pixels outside the search range for the second processing unit using the FRUC mode among the plurality of second processing units included in the first processing unit, and The encoding process is performed with reference to the pixel (S204).

For example, in the FRUC mode, the encoding apparatus 100 excludes candidate motion vectors having a pixel outside the search range as a reference from the plurality of candidate motion vectors derived from the motion vector of the processed block from the evaluation target (S204) Cost evaluation is performed on the subsequent candidate motion vector (S205).

For example, in the candidate motion vector exclusion (S204), the coding apparatus 100 further performs candidate processing that requires pixels outside the search range in other processing related to predicted image generation applied after performing the FRUC processing. Exclude vectors from evaluation.

For example, if the encoding apparatus 100 is another process related to predicted image generation applied after performing the FRUC process in the FRUC mode, there is another process requiring pixels outside the search range, A predicted image is generated without performing any other processing.

For example, in the setting of the search range (S201), the encoding apparatus 100 uses a reference index for specifying a processed picture that can be referred to, the size of the search area in the reference index, and the center position of the search area in the reference index. The search range is set using information including the shift amount.

For example, the encoding apparatus 100 switches the size of the search area according to the total number of reference indexes.

For example, the encoding apparatus 100 sets the size of the search area such that the sum of the search areas in the reference index is equal to or less than a specific value.

For example, the encoding apparatus 100 defines the upper limit value of the total number of reference indexes and the size of the search area or the total sum of the search areas in association with the profile value or the level value. The encoding apparatus 100 sets the total number of reference indexes and the size of the search area so as to be a value less than or equal to the upper limit value, according to the profile value or level value assigned to the target stream.

For example, the encoding device 100 associates a plurality of reference indices with one referenceable processed picture.

For example, the coding apparatus 100 may set a reference index for specifying a referenceable processed picture and information for specifying the size of a search area in a sequence header area, a picture header area, a slice header area, or an auxiliary information area. Encode.

For example, the encoding device 100 switches the total number of reference indexes and the size of the search region according to the processing capability of the decoding device 200.

For example, the encoding apparatus 100 switches the total number of reference indexes and the size of the search area according to the profile value or the level value assigned to the target stream.

For example, the encoding apparatus 100 switches the total number of reference indexes and the size of the search area according to the size of the target picture.

For example, the encoding apparatus 100 sets a common value for all first processing units belonging to the target picture or target slice, and a method of deriving the center position shift amount of the search area for each first processing unit. The two methods, method and method, are switched for each target picture.

For example, the encoding apparatus 100 encodes information for specifying which of the two methods is to be used, in a picture header area or a slice header area.

In addition, the decoding apparatus 200 according to an aspect of the present disclosure sets a search range to be commonly used in the first processing unit (for example, CTU) (S201), and the plurality of second processing units included in the first processing unit. In the second processing unit using inter prediction, reference to pixels outside the search range is restricted, and decoding processing is performed using pixels within the search range (S204 or S210). Thus, the amount of access to the memory storing the image of the processed area can be limited, so that the processing time related to data transfer can be suppressed and the amount of processing can be reduced.

For example, in the setting of the search range (S201), the decoding device 200 includes information including a processable reference picture, the size of the search area in the processed picture, and the center position shift amount of the search area in the processed picture. Use to set the search range.

For example, the decoding apparatus 200 switches the size of the search area in accordance with the number of referable processed pictures.

For example, the decoding device 200 sets the size of the search area such that the sum of the search areas in the referenceable processed pictures is equal to or less than a specific value.

For example, the decoding device 200 specifies the upper limit value of the number of processable pictures that can be referred to and the size of the search area, or the total of the search areas in association with the profile value or the level value. The decoding apparatus 200 sets the number of referable processed pictures and the size of the search area so that the value becomes equal to or less than the upper limit value according to the profile value or the level value assigned to the target stream.

For example, the information indicating that the decoding apparatus 200 has not selected the inter prediction mode requiring pixels outside the search range in all the second processing units included in the first processing unit is a sequence header area, a picture Decode from the header area, slice header area or auxiliary information area.

For example, the decoding device 200 derives the center position shift amount of the search area for each first processing unit.

For example, the decoding device 200 is a motion vector assigned to the second processing unit included in the processed first processing unit located in the spatial or temporal periphery of the target first processing unit, as the center position shift amount of the search area. It derives using.

For example, as the central position shift amount of the search area, a common value is set to all the first processing units included in the target picture or the target slice, and the decoding apparatus 200 is information for specifying the common value. Are decoded from the picture header area or slice header area to identify a common value.

For example, when the position of the search range is specified, the decoding device 200 uses the memory storing the image data of the processed picture to set the reference pixel data of the search range set for the target first processing unit. The transfer is started, and after the transfer is completed, processing of the target first processing unit is started.

For example, the decoding apparatus 200 does not wait for the processing of the first processing unit whose processing order is immediately before, but the search set for the target first processing unit from the memory storing the image data of the processed picture. Start transferring range reference pixel data.

For example, the decoding apparatus 200 refers to a region overlapping the search range set for the already processed first processing unit among the reference pixel data of the search range set for the target first processing unit. The reference pixel data is transferred from the memory except for the pixel data.

For example, the decoding device 200 restricts reference to pixels outside the search range for the second processing unit using the FRUC mode among the one or more second processing units included in the first processing unit, and the search range Decoding processing is performed using the pixels in (S204).

For example, in the FRUC mode, the decoding apparatus 200 excludes candidate motion vectors having a pixel outside the search range as a reference from the plurality of candidate motion vectors derived from the motion vector of the processed block from the evaluation target (S204). The cost evaluation is performed on the candidate motion vector of (S205).

For example, in the candidate motion vector exclusion (S204), the decoding apparatus 200 further requires a pixel outside the search range in another process related to predicted image generation applied after performing the FRUC process. Exclude from the evaluation.

For example, the decoding apparatus 200 is another process related to predicted image generation applied after performing the FRUC process in the FRUC mode, and there is another process that requires a pixel outside the search range. The predicted image is generated without performing the processing of

For example, in the setting of the search range (S201), the decoding device 200 refers to a reference index for specifying a processed picture that can be referred to, the size of the search area in the reference index, and the center position shift of the search area in the reference index The search range is set using information including:

For example, the decoding device 200 switches the size of the search area according to the total number of reference indexes.

For example, the decoding device 200 sets the size of the search area such that the sum of the search areas in the reference index is less than or equal to a specific value.

For example, the decoding device 200 specifies the upper limit value of the total number of reference indexes and the size of the search area or the total of the search areas in association with the profile value or the level value. The decoding apparatus 200 sets the total number of reference indexes and the size of the search area so as to be a value less than or equal to the upper limit value, according to the profile value or level value assigned to the target stream.

For example, the decoding apparatus 200 decodes a reference index for specifying a referenceable processed picture and information for specifying the size of a search area from a sequence header area, a picture header area, a slice header area, or an auxiliary information area. And specify the size of the reference index and the search area.

For example, the decoding device 200 derives the center position shift amount of the search area for each first processing unit, and sets the common value to all the first processing units belonging to the target picture or the target slice. And switch the two methods for each target picture.

For example, the decoding apparatus 200 decodes information for specifying which of the two methods is to be used from the picture header area or the slice header area, and specifies which of the two methods is to be used.

In addition, encoding apparatus 100 according to the present embodiment divides image into a plurality of blocks, and intra prediction unit 124 that predicts a block included in the image using a reference picture included in the image. An inter prediction unit 126 that predicts a block included in the image using a reference block included in another image different from the image; a loop filter unit 120 that applies a filter to the block included in the image; A conversion unit 106 that converts a prediction error between the prediction signal generated by the intra prediction unit 124 or the inter prediction unit 126 and the original signal to generate a conversion coefficient, and quantizes the conversion coefficient to generate a quantization coefficient Quantization unit 108, and entropy that generates a coded bit stream by variable-length coding the quantization coefficient. It includes an encoding unit 110, a. The inter prediction unit 126 sets a search range to be commonly used in the first processing unit (for example, CTU) (S201), and the inter prediction unit among the one or more second processing units (for example, CU) included in the first processing unit For the second processing unit using prediction, reference to pixels outside the search range is restricted, and coding processing is performed with reference to pixels within the search range (S204 or S210).

In addition, the decoding apparatus 200 according to the present embodiment decodes a coded bit stream and outputs a quantization coefficient (entropy decoding unit 202), and inversely quantizes the quantization coefficient to output a transform coefficient. An inverse quantization unit 204 for performing inverse transform, an inverse transform unit 206 for inversely transforming the transform coefficient and outputting a prediction error, and an intra prediction unit 216 for predicting a block included in the image using a reference picture included in the image An inter prediction unit 218 that predicts a block included in the image using a reference block included in another image different from the image; and a loop filter unit 212 that applies a filter to the block included in the image Prepare. The inter prediction unit 218 sets a search range to be commonly used in the first processing unit (for example, CTU) (S201), and the inter prediction unit among the one or more second processing units (for example, CU) included in the first processing unit For the second processing unit using prediction, reference to pixels outside the search range is restricted, and decoding processing is performed with reference to pixels within the search range (S204 or S210).

[Implementation example of encoding device]
FIG. 21 is a block diagram showing an implementation example of the coding apparatus 100 according to Embodiment 1. The coding apparatus 100 includes a circuit 160 and a memory 162. For example, the components of the coding apparatus 100 shown in FIG. 1 are implemented by the circuit 160 and the memory 162 shown in FIG.

The circuit 160 is a circuit that performs information processing and 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 also be an assembly of a plurality of electronic circuits. Also, for example, the circuit 160 may play a role of a plurality of components excluding the component for storing information among the plurality of components 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 moving pictures is stored. The memory 162 may be an electronic circuit or may be connected to the circuit 160. The memory 162 may also be included in the circuit 160. Also, the memory 162 may be a collection of a plurality of electronic circuits. In addition, 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, the moving image to be encoded may be stored in the memory 162, or a bit string corresponding to the encoded moving image may be stored. The memory 162 may also store a program for the circuit 160 to encode a moving image.

Also, for example, the memory 162 may play a role of a component for storing information among the plurality of components of the encoding device 100 illustrated in FIG. 1 and the like. Specifically, the memory 162 may play the role of the block memory 118 and the frame memory 122 shown in FIG. More specifically, the memory 162 may store reconstructed blocks, reconstructed pictures, and the like.

In the coding apparatus 100, all of the plurality of components shown in FIG. 1 and the like may not 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 performed by another device. Then, in the encoding apparatus 100, part of the plurality of components shown in FIG. 1 and the like is implemented, and part of the plurality of processes described above is performed, whereby motion compensation is efficiently performed. It will be.

[Implementation example of decryption device]
FIG. 22 is a block diagram showing an implementation example of the decoding device 200 according to Embodiment 1. The decoding device 200 includes a circuit 260 and a memory 262. For example, the plurality of components of the decoding apparatus 200 shown in FIG. 10 are implemented by the circuit 260 and the memory 262 shown in FIG.

The circuit 260 is a circuit that performs information processing and 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. Also, the circuit 260 may be a collection of a plurality of electronic circuits. Also, for example, the circuit 260 may play the role of a plurality of components excluding the component for storing information among the plurality of components 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. Also, the memory 262 may be included in the circuit 260. Further, the memory 262 may be a collection of a plurality of electronic circuits. Also, the memory 262 may be a magnetic disk or an optical disk, or may be expressed as a storage or a recording medium. The memory 262 may be either a non-volatile memory or a volatile memory.

For example, in the memory 262, a bit string corresponding to a coded moving image may be stored, or a moving image corresponding to a decoded bit string may be stored. Also, the memory 262 may store a program for the circuit 260 to decode a moving image.

Also, for example, the memory 262 may play the role of a component for storing information among the plurality of components of the decoding device 200 illustrated in FIG. 10 and the like. Specifically, the memory 262 may play the role of the block memory 210 and the frame memory 214 shown in FIG. More specifically, the memory 262 may store reconstructed blocks, reconstructed pictures, and the like.

In the decoding apparatus 200, all of the plurality of components shown in FIG. 10 and the like may not be mounted, 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 performed by another device. Then, in the decoding device 200, part of the plurality of components shown in FIG. 10 and the like is implemented, and part of the plurality of processes described above is performed, whereby motion compensation is efficiently performed. .

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

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

Further, in the present embodiment, each component may be configured by dedicated hardware or implemented 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 Circuitry) and a storage device (Storage) electrically connected to the processing circuit and accessible to the processing circuit. You may have. For example, processing circuitry may correspond to

circuitry

160 or 260 and storage may correspond to

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. In addition, when the processing circuit includes a program execution unit, the storage device stores a software program executed by the program execution unit.

Here, software for realizing the encoding apparatus 100 or the decoding apparatus 200 of the present embodiment is a program as follows.

Also, 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 processing that a particular component performs. Further, the order of executing the processing may be changed, or a plurality of processing may be executed in parallel. Further, the coding and decoding apparatus may include the coding apparatus 100 and the decoding apparatus 200.

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 the decoding apparatus 200 is not limited to this embodiment. The encoding apparatus 100 and the decoding apparatus 200 may be configured by combining various modifications in the present embodiment that may occur to those skilled in the art without departing from the spirit of the present disclosure, or by combining components in different embodiments. It may be included within the scope of the aspect of.

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

Second Embodiment
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 of the functional blocks is usually realized by a program execution unit such as a processor reading and executing software (program) recorded in a recording medium such as a ROM. The software may be distributed by downloading or the like, or may be distributed by being recorded in a recording medium such as a semiconductor memory. Of course, it is also possible to realize each functional block by hardware (dedicated circuit).

Also, 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. Moreover, the processor that executes the program may be singular or plural. 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 examples, and various modifications are possible, which are also included in the scope of the aspects of the present disclosure.

Furthermore, an application example of the moving picture coding method (image coding method) or the moving picture decoding method (image decoding method) shown in each of the above-described embodiments and a system using the same will be described. The system is characterized by having an image coding apparatus using an image coding method, an image decoding apparatus using an image decoding method, and an image coding / decoding apparatus provided with both. Other configurations in the system can be suitably modified as the case may be.

[Example of use]
FIG. 23 is a diagram showing an overall configuration of a content supply system ex100 for realizing content distribution service. The area for providing communication service 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 this content supply system ex100, 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 service provider ex102 or the communication network ex104 and the base stations ex106 to ex110 on the Internet ex101 Is connected. The content supply system ex100 may connect any of the above-described elements in combination. The respective devices may be connected to each other directly or indirectly via a telephone network, near-field radio, etc., not via the base stations ex106 to ex110 which are fixed wireless stations. Also, the streaming server ex103 is connected to each device such as the computer ex111, the game machine ex112, the camera ex113, the home appliance ex114, and the smartphone ex115 via the Internet ex101 or the like. Also, the streaming server ex103 is connected to a terminal or the like in a hotspot in the aircraft ex117 via the satellite ex116.

A radio access point or a hotspot may be used instead of base stations ex106 to ex110. Also, the streaming server ex103 may be directly connected to the communication network ex104 without the internet ex101 or the internet service provider ex102, or may be directly connected with the airplane ex117 without the satellite ex116.

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

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

In the content supply system ex100, when a terminal having a photographing function is connected to the streaming server ex103 through the base station ex106 or the like, live distribution and the like become possible. In live distribution, a terminal (a computer ex111, a game machine ex112, a camera ex113, a home appliance ex114, a smartphone ex115, a terminal in an airplane ex117, etc.) transmits the still image or moving image content captured by the user using the terminal. The encoding process described in each embodiment is performed, and video data obtained by the encoding and sound data obtained by encoding a 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 coding apparatus according to an aspect of the present disclosure.

On the other hand, the streaming server ex 103 streams the content data transmitted to the requested client. The client is a computer ex111, a game machine ex112, a camera ex113, a home appliance ex114, a smartphone ex115, a terminal in the airplane ex117 or the like capable of decoding the above-mentioned encoded data. Each device that receives 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]
Also, the streaming server ex103 may be a plurality of servers or a plurality of computers, and may process, record, or distribute data in a distributed manner. For example, the streaming server ex103 may be realized by a CDN (Contents Delivery Network), and content delivery may be realized by a network connecting a large number of edge servers distributed around the world and the edge servers. In the CDN, physically close edge servers are dynamically assigned according to clients. The delay can be reduced by caching and distributing the content to the edge server. In addition, when there is an error or when the communication status changes due to an increase in traffic etc., processing is distributed among multiple edge servers, or the distribution subject is switched to another edge server, or a portion of the network where a failure has occurred. Since the delivery can be continued bypassing, high-speed and stable delivery can be realized.

In addition to the distributed processing of distribution itself, each terminal may perform encoding processing of captured data, or may perform processing on the server side, or may share processing with each other. As an example, generally in the encoding process, a processing loop is performed twice. In the first loop, the complexity or code amount of the image in frame or scene units is detected. In the second loop, processing is performed to maintain the image quality and improve the coding efficiency. For example, the terminal performs a first encoding process, and the server receiving the content performs a 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 substantially real time, the first encoded data made by the terminal can also be received and reproduced by another terminal, enabling more flexible real time delivery Become.

As another example, the camera ex 113 or the like extracts a feature amount from an image, compresses data relating to the feature amount as metadata, and transmits the data to the server. The server performs compression according to the meaning of the image, for example, determining the importance of the object from the feature amount and switching the quantization accuracy. Feature amount data is particularly effective in improving the accuracy and efficiency of motion vector prediction at the time of second compression in the server. Also, the terminal may perform simple coding such as VLC (variable length coding) and the server may perform coding with a large processing load such as CABAC (context adaptive binary arithmetic coding method).

As still another example, in a stadium, a shopping mall, or a factory, there may be a plurality of video data in which substantially the same scenes are shot by a plurality of terminals. In this case, for example, a unit of GOP (Group of Picture), a unit of picture, or a tile into which a picture is divided, using a plurality of terminals for which photographing was performed and other terminals and servers which are not photographing as necessary. The encoding process is allocated in units, etc., and distributed processing is performed. This reduces delay and can realize more real time performance.

Further, since a plurality of video data are substantially the same scene, the server may manage and / or instruct the video data captured by each terminal to be mutually referred to. Alternatively, the server may receive the encoded data from each terminal and change the reference relationship among a plurality of data, or may correct or replace the picture itself and re-encode it. This makes it possible to generate streams with enhanced quality and efficiency of each piece of data.

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

Thus, the encoding process can be performed by the terminal or one or more servers. Therefore, in the following, although the description such as "server" or "terminal" is used as the subject of processing, part or all of the processing performed by the server may be performed by the terminal, or the processing performed by the terminal Some or all may be performed on the server. In addition, with regard to these, the same applies to the decoding process.

[3D, multi-angle]
In recent years, it has been increasingly used to integrate and use different scenes captured by terminals such as a plurality of cameras ex113 and / or smartphone ex115 which are substantially synchronized with each other, or images or videos of the same scene captured from different angles. There is. The images captured by each terminal are integrated based on the relative positional relationship between the terminals acquired separately, or an area where the feature points included in the image coincide with each other.

The server not only encodes a two-dimensional moving image, but also automatically encodes a still image based on scene analysis of the moving image or at a time designated by the user and transmits it to the receiving terminal. It is also good. Furthermore, if the server can acquire relative positional relationship between the imaging terminals, the three-dimensional shape of the scene is not only determined based on the two-dimensional moving image but also the video of the same scene captured from different angles. Can be generated. Note that the server may separately encode three-dimensional data generated by a point cloud or the like, or an image to be transmitted to the receiving terminal based on a result of recognizing or tracking a person or an object using the three-dimensional data. Alternatively, it may be generated by selecting or reconfiguring from videos taken by a plurality of terminals.

In this way, the user can enjoy the scene by arbitrarily selecting each video corresponding to each photographing terminal, or from the three-dimensional data reconstructed using a plurality of images or videos, the video of the arbitrary viewpoint You can also enjoy the extracted content. Furthermore, the sound may be picked up from a plurality of different angles as well as the video, and the server may multiplex the sound from a specific angle or space with the video and transmit it according to the video.

Also, in recent years, content in which the real world and the virtual world are associated, such as Virtual Reality (VR) and Augmented Reality (AR), has also become widespread. In the case of VR images, the server may create viewpoint images for the right eye and for the left eye, respectively, and may perform coding to allow reference between each viewpoint video using Multi-View Coding (MVC) or the like. It may be encoded as another stream without reference. At the time of decoding of another stream, reproduction may be performed 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 camera information in the real space based on the three-dimensional position or the movement of the user's viewpoint. The decoding apparatus 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 superimposed data by smoothly connecting. Alternatively, the decoding device transmits the motion of the user's viewpoint to the server in addition to the request for virtual object information, and the server creates superimposed data in accordance with the motion 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 as well as RGB, and the server sets the α value of a portion other than the object created from the three-dimensional data to 0 etc., and the portion is transparent , May be encoded. Alternatively, the server may set RGB values of predetermined values as a background, such as chroma key, and generate data in which the portion other than the object has a background color.

Similarly, the decryption processing of the distributed data may be performed by each terminal which is a client, may be performed by the server side, or may be performed sharing each other. As one example, one terminal may send a reception request to the server once, the content corresponding to the request may be received by another terminal and decoded, and the decoded signal may be transmitted to a device having a display. Data of high image quality can be reproduced by distributing processing and selecting appropriate content regardless of the performance of the communicable terminal itself. As another example, while receiving image data of a large size by a TV or the like, a viewer's personal terminal may decode and display a partial area such as a tile in which a picture is divided. Thereby, it is possible to confirm at hand the area in which the user is in charge or the area to be checked in more detail while sharing the whole image.

Also, from now on, for communication under connection using a delivery system standard such as MPEG-DASH under a situation where multiple short distance, middle distance or long distance wireless communication can be used regardless of indoor or outdoor. It is expected to receive content seamlessly while switching the appropriate data. As a result, the user can switch in real time while freely selecting not only his own terminal but also a decoding apparatus or display apparatus such as a display installed indoors and outdoors. In addition, decoding can be performed while switching between a terminal to be decoded and a terminal to be displayed, based on own position information and the like. This makes it possible to move while displaying map information on the wall surface or part of the ground of the next building in which the displayable device is embedded while moving to the destination. Also, access to encoded data over the network, such as encoded data being cached on a server that can be accessed in a short time from a receiving terminal, or copied to an edge server in a content delivery service, etc. It is also possible to switch the bit rate of the received data based on ease.

[Scalable coding]
Content switching will be described using a scalable stream compression-coded by applying the moving picture coding method shown in each of the above-described embodiments shown in FIG. The server may have a plurality of streams with the same content but different qualities as individual streams, but is temporally / spatial scalable which is realized by coding into layers as shown in the figure. The configuration may be such that the content is switched using the feature of the stream. That is, the decoding side determines low-resolution content and high-resolution content by determining which layer to decode depending on the internal factor of performance and external factors such as the state of the communication band. It can be switched freely and decoded. For example, when it is desired to view the continuation of the video being watched by the smartphone ex115 while moving on a device such as the Internet TV after returning home, the device only has to decode the same stream to different layers, so the burden on the server side Can be reduced.

Furthermore, as described above, the picture is encoded for each layer, and the enhancement layer includes meta information based on statistical information of the image, etc., in addition to the configuration for realizing the scalability in which the enhancement layer exists above the base layer. The decoding side may generate high-quality content by super-resolving a picture of the base layer based on the meta information. The super resolution may be either an improvement in the SN ratio at the same resolution or an expansion of the resolution. Meta information includes information for identifying linear or non-linear filter coefficients used for super-resolution processing, or information for identifying parameter values in filter processing used for super-resolution processing, machine learning or least squares operation, etc. .

Alternatively, the picture may be divided into tiles or the like according to the meaning of an object or the like in the image, and the decoding side may be configured to decode only a part of the area by selecting the tile to be decoded. Also, by storing the attribute of the object (person, car, ball, etc.) and the position in the image (coordinate position in the same image, etc.) as meta information, the decoding side can position the desired object based on the meta information And determine the tile that contains the object. For example, as shown in FIG. 25, meta-information is stored using a data storage structure different from pixel data, such as 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 of a plurality of pictures, such as streams, sequences, or random access units. As a result, the decoding side can acquire the time when a specific person appears in the video and the like, and can identify the picture in which the object exists and the position of the object in the picture by combining the information with the picture unit.

Web Page Optimization
FIG. 26 is a diagram showing an example of a display screen of a web page in the computer ex111 and the like. FIG. 27 is a diagram showing an example of a display screen of a web page in the smartphone ex115 and the like. As shown in FIGS. 26 and 27, the web page may include a plurality of link images which are links to image content, and the appearance differs depending on the browsing device. When multiple link images are visible on the screen, the display device until the user explicitly selects the link image, or until the link image approaches near the center of the screen or the entire link image falls within the screen The (decoding device) displays still images or I pictures of each content as link images, displays images such as gif animation with a plurality of still images or I pictures, etc., receives only the base layer Decode and display.

When the link image is selected by the user, the display device decodes the base layer with the highest priority. Note that the display device may decode up to the enhancement layer if there is information indicating that the content is scalable in the HTML configuring the web page. Also, in order to secure real-time capability, the display device decodes only forward referenced pictures (I picture, P picture, forward referenced only B picture) before the selection or when the communication band is very strict. And, by displaying, it is possible to reduce the delay between the decoding time of the leading picture and the display time (delay from the start of decoding of the content to the start of display). In addition, the display device may roughly ignore the reference relationship of pictures and roughly decode all B pictures and P pictures with forward reference, and may perform normal decoding as time passes and the number of received pictures increases.

[Auto run]
In addition, when transmitting or receiving still image or video data such as two-dimensional or three-dimensional map information for automatic traveling or driving assistance of a car, the receiving terminal is added as image information belonging to one or more layers as meta information Information on weather or construction may also be received, and these may be correlated and decoded. The meta information may belong to the layer or may be simply multiplexed with the image data.

In this case, since a car including a receiving terminal, a drone or an airplane moves, the receiving terminal transmits the position information of the receiving terminal at the time of reception request to seamlessly receive and decode 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 state of the communication band. become.

As described above, in the content providing system ex100, the client can receive, decode, and reproduce the encoded information transmitted by the user in real time.

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

At the time of shooting, the server performs recognition processing such as shooting error, scene search, meaning analysis, and object detection from the original image or encoded data after shooting in real time or by accumulation. Then, the server manually or automatically corrects out-of-focus or camera shake, etc. based on the recognition result, or a scene with low importance such as a scene whose brightness is low or out of focus compared with other pictures. Make edits such as deleting, emphasizing the edge of an object, or changing the color. The server encodes the edited data based on the edited result. It is also known that the audience rating drops when the shooting time is too long, and the server works not only with scenes with low importance as described above, but also moves as content becomes within a specific time range according to the shooting time. Scenes with a small amount of motion may be clipped automatically based on the image processing result. Alternatively, the server may generate and encode a digest based on the result of semantic analysis of the scene.

In some cases, there are cases where personal content may infringe copyright, author's personality right, portrait right, etc. as it is, and it is inconvenient for the individual, such as the range of sharing exceeds the intended range. There are also cases. Thus, for example, the server may change and encode the face of a person at the periphery of the screen, or the inside of a house, etc. into an image out of focus. In addition, the server recognizes whether or not the face of a person different from the person registered in advance appears in the image to be encoded, and if so, performs processing such as mosaicing the face portion. May be Alternatively, the user designates a person or background area desired to process an image from the viewpoint of copyright etc. as preprocessing or post-processing of encoding, 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, it is possible to replace the image of the face part while tracking the person in the moving image.

Also, since viewing of personal content with a small amount of data has a strong demand for real-time performance, the decoding apparatus first receives the base layer with the highest priority, and performs decoding and reproduction, although it depends on the bandwidth. The decoding device may receive the enhancement layer during this period, and may play back high-quality video including the enhancement layer if it is played back more than once, such as when playback is looped. In the case of a stream in which scalable coding is performed as described above, it is possible to provide an experience in which the stream gradually becomes smart and the image becomes better although it is a rough moving image when it is not selected or when it starts watching. Besides scalable coding, the same experience can be provided even if the coarse stream played back first and the second stream coded with reference to the first moving image are configured as one stream .

[Other use cases]
Also, these encoding or decoding processes are generally processed in an LSI ex 500 that each terminal has. The LSI ex 500 may be a single chip or a plurality of chips. Software for moving image encoding or decoding is incorporated in any recording medium (CD-ROM, flexible disk, hard disk, etc.) readable by computer ex111 or the like, and encoding or decoding is performed using the software. It is also good. Furthermore, when the smartphone ex115 is equipped with 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 ex 500 included in the smartphone ex 115.

The LSI ex 500 may be configured to download and activate application software. In this case, the terminal first determines whether the terminal corresponds to the content coding scheme or has the ability to execute a specific service. If the terminal does not support the content encoding method or does not have the ability to execute a specific service, the terminal downloads the codec or application software, and then acquires and reproduces the content.

Further, the present invention is not limited to the content supply system ex100 via the Internet ex101, but also to a system for digital broadcasting at least a moving picture coding apparatus (image coding apparatus) or a moving picture decoding apparatus (image decoding apparatus) of the above embodiments. Can be incorporated. There is a difference in that it is multicast-oriented with respect to the configuration in which the content supply system ex100 can be easily unicasted, since multiplexed data in which video and sound are multiplexed is transmitted on broadcast radio waves using satellites etc. Similar applications are possible for the encoding process and the decoding process.

[Hardware configuration]
FIG. 28 is a diagram showing the smartphone ex115. FIG. 29 is a diagram showing an example configuration of the smartphone ex115. The smartphone ex115 receives an antenna ex450 for transmitting and receiving radio waves to and from the base station ex110, a camera unit ex465 capable of taking video and still images, a video taken by the camera unit ex465, and the antenna ex450 And a display unit ex <b> 458 for displaying data obtained by decoding an image 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, Identify the user, the memory unit ex 467 capable of storing encoded video or still image, recorded voice, received video or still image, encoded data such as mail, or decoded data, and specify a network, etc. And a slot unit ex464 that is an interface unit with the SIM ex 468 for authenticating access to various data. Note that an external memory may be used instead of the memory unit ex467.

Further, a main control unit ex460 that integrally controls the display unit ex458 and the operation unit ex466, 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, / Demodulation unit ex452, multiplexing / demultiplexing unit ex453, audio signal processing unit ex454, slot unit ex464, and memory unit ex467 are connected via a bus ex470.

When the power supply key is turned on by the user's operation, the power supply circuit unit ex461 activates the smartphone ex115 to an operable state by supplying power from the battery pack to each unit.

The smartphone ex115 performs processing such as call and data communication based on control of the main control unit ex460 having a CPU, a ROM, a RAM, and the like. At the time of a call, the audio signal collected by the audio input unit ex456 is converted to a digital audio signal by the audio 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 processing and frequency conversion processing, transmission is performed via the antenna ex450. Further, the received data is amplified and subjected to frequency conversion processing and analog-to-digital conversion processing, subjected to spectrum despreading processing by modulation / demodulation unit ex452, and converted to an analog sound signal by sound signal processing unit ex454. Output from In the data communication mode, text, still images, or video data are sent to the main control unit ex460 via the operation input control unit ex462 by the operation of the operation unit ex466 or the like of the main unit, and transmission and reception processing is similarly performed. In the case of transmitting video, still images, or video and audio in the data communication mode, the video signal processing unit ex 455 executes the video signal stored in the memory unit ex 467 or the video signal input from the camera unit ex 465 as described above. The video data is compressed and encoded by the moving picture encoding method shown in the form, and the encoded video data is sent to the multiplexing / demultiplexing unit ex453. Further, the audio signal processing unit ex454 encodes an audio signal collected by the audio input unit ex456 while capturing a video or a still image with the camera unit ex465, and sends the encoded audio data to the multiplexing / demultiplexing unit ex453. Do. The multiplexing / demultiplexing unit ex453 multiplexes the encoded video data and the encoded audio data according to a predetermined method, and performs modulation processing and conversion by the modulation / demodulation unit (modulation / demodulation circuit unit) ex452 and the transmission / reception unit ex451. It processes and transmits via antenna ex450.

When a video attached to an e-mail or a chat or a video linked to a web page or the like is received, the multiplexing / demultiplexing unit ex453 multiplexes in order to decode multiplexed data received via the antenna ex450. 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, and The converted audio data is supplied to the audio signal processing unit ex 454. The video signal processing unit ex 455 decodes the video signal by the moving picture decoding method corresponding to the moving picture coding method described in each of the above embodiments, and is linked from the display unit ex 458 via the display control unit ex 459. An image or a still image included in the moving image file is displayed. The audio signal processing unit ex 454 decodes the audio signal, and the audio output unit ex 457 outputs the audio. Furthermore, since real-time streaming is widespread, depending on the user's situation, it may happen that sound reproduction is not socially appropriate. Therefore, as an initial value, it is preferable to have 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.

Also, although the smartphone ex115 has been described as an example, in addition to a transceiving terminal having both an encoder and a decoder as a terminal, a transmitting terminal having only the encoder and a receiver having only the decoder There are three possible implementation forms: terminals. Furthermore, in the digital broadcasting system, it has been described that multiplexed data in which audio data is multiplexed with video data is received or transmitted, but in multiplexed data, character data related to video other than audio data is also described. It may be multiplexed, or video data itself may be received or transmitted, not multiplexed data.

Although the main control unit ex 460 including the CPU is described as controlling the encoding or decoding process, the terminal often includes a GPU. Therefore, a configuration in which a large area is collectively processed using the performance of the GPU may be performed using a memory shared by the CPU and the GPU, or a memory whose address is managed so as to be commonly used. As a result, coding time can be shortened, real time property can be secured, and low delay can be realized. In particular, it is efficient to perform processing of motion search, deblock filter, sample adaptive offset (SAO), and transform / quantization collectively in units of pictures or the like on the GPU instead of the CPU.

The present disclosure is applicable to, for example, a television receiver, a digital video recorder, a car navigation system, a mobile phone, a digital camera, a digital video camera, a video conference system, an electronic mirror, and the like.

Reference Signs List 100 encoder 102 division unit 104 subtraction unit 106 transformation unit 108 quantization unit 110

entropy encoding unit

112, 204 inverse quantization unit 114, 206

inverse transformation unit

116, 208

addition unit

118, 210

block memory

120, 212

loop filter Unit

122, 214

Frame memory

124, 216

Intra prediction unit

126, 218

Inter prediction unit

128, 220

Prediction control unit

160, 260

Circuit

162, 262 Memory 200 Decoding device 202 Entropy decoding unit

Claims

Circuit,
With memory,
The circuit uses the memory to
Set a search range commonly used in the first processing unit,
For the second processing unit using inter prediction among the one or more second processing units included in the first processing unit, the reference of the pixels outside the search range is restricted, and the pixels in the search range are referred to Coding device that performs coding processing.
The first processing unit is a block unit composed of one or more second processing units which is a basic division unit of a picture, or a predefined size composed of one or more second processing units The encoding device according to claim 1, wherein the encoding unit is a block unit of
With respect to the target second processing unit included in the first processing unit,
Among the plurality of inter prediction modes, motion compensation processing using a motion vector assigned to the inter prediction mode to be selected excludes the inter prediction mode that refers to pixels outside the search range,
Select one mode from inter prediction mode and intra prediction mode after exclusion,
The encoding apparatus according to claim 1, wherein the encoding process is performed using the selected mode.
In the exclusion of the inter prediction mode, inter prediction which requires a pixel outside the search range in another process related to predicted image generation applied to the selection target inter prediction mode other than the motion compensation process is further performed. The encoding device according to claim 3, wherein the mode is excluded.
In the inter prediction mode to be selected, there is another process related to prediction image generation to be applied other than the motion compensation process, and there is the other process requiring a pixel outside the search range, the other process The encoding apparatus according to claim 3, wherein the prediction image is generated without performing the process of (4).
In the setting of the search range, the search range is set using information including a processed picture to which reference can be made, a size of a search area in the processed picture, and a center position shift amount of the search area in the processed picture. The encoding device according to claim 1.
The encoding device according to claim 6, wherein the size of the search area is switched according to the number of the reference-processed processed pictures.
The encoding apparatus according to claim 6, wherein the size of the search area is set such that the sum of the search areas in the referenceable processed picture is equal to or less than a specific value.
An upper limit value of the number of referable processed pictures and the size of the search area or the sum of the search areas is defined in association with a profile value or a level value.
The number of the referable processed pictures and the size of the search area are set according to the profile value or the level value assigned to the target stream so that the value becomes equal to or less than the upper limit value. Encoding device.
Information indicating that the inter prediction mode requiring the pixels outside the search range is not selected in all the second processing units included in the first processing unit, a sequence header area, a picture header area, and a slice header The encoding apparatus according to claim 1, wherein the encoding is performed in an area or an auxiliary information area.
The encoding apparatus according to claim 3, wherein whether to exclude an inter prediction mode that refers to a pixel outside the search range is switched according to the processing capability of the decoding apparatus.
The encoding apparatus according to claim 3, wherein whether to exclude an inter prediction mode that refers to a pixel outside the search range is switched according to a profile value or a level value assigned to a target stream.
The encoding apparatus according to claim 3, wherein whether to exclude an inter prediction mode that refers to a pixel outside the search range is switched according to the size of the target picture.
The encoding apparatus according to claim 6, wherein the center position shift amount of the search area is a shift amount between a position of a target first processing unit in a target picture and a position of the search area in a processed picture to be referred to.
The encoding apparatus according to claim 6, wherein the center position shift amount of the search area is derived for each first processing unit.
The center position shift amount of the search area is derived using a motion vector assigned to a second processing unit included in a processed first processing unit located in the spatial or temporal periphery of the target first processing unit. Item 7. The encoding device according to Item 6.
17. The encoding device according to claim 16, wherein the processed first processing unit is a processed first processing unit other than the first processing unit in which the processing order is immediately before the target first processing unit.
As the center position shift amount of the search area, a common value is set for all first processing units included in the target picture or target slice,
The encoding apparatus according to claim 6, wherein the information for identifying the common value is encoded in a picture header area or a slice header area.
The encoding apparatus according to claim 18, wherein the common value is set to a value at which the shift of the center position is zero.
The encoding apparatus according to claim 18, wherein the common value is derived using statistics of a plurality of motion vectors derived in a plurality of second processing units included in a processed picture.
When the position of the search range is specified, transfer of reference pixel data of the search range set for the target first processing unit is started from a memory storing image data of a processed picture, The encoding device according to claim 1, wherein processing of the target first processing unit is started after transfer is completed.
Reference pixel data of the search range set for a target first processing unit from a memory storing image data of a processed picture without waiting for processing of the first processing unit whose processing order is immediately before The encoding apparatus according to claim 17, wherein transfer of is started.
Among reference pixel data of the search range set for the target first processing unit, except for reference pixel data of an area overlapping the search range set for the already processed first processing unit The encoding device according to claim 1, wherein the reference pixel data is transferred from a memory.
For the second processing unit using the FRUC mode among the plurality of second processing units included in the first processing unit, reference to pixels outside the search range is restricted, and pixels within the search range are referred to The encoding apparatus according to claim 1, wherein the encoding process is performed.
In the FRUC mode,
The candidate motion vectors with reference to the pixels outside the search range are excluded from evaluation targets from a plurality of candidate motion vectors derived from the motion vector of the processed block,
The coding apparatus according to claim 24, wherein cost evaluation is performed on candidate motion vectors after exclusion.
In the removal of the candidate motion vector, a candidate motion vector requiring a pixel outside the search range is further excluded from the evaluation target in another process related to prediction image generation applied after performing the FRUC process. 25. The encoding device according to 25.
In the FRUC mode, another process related to predicted image generation applied after the FRUC process is performed, and there is the other process requiring a pixel outside the search range, the other process is performed. The encoding apparatus according to claim 25, wherein the prediction image is generated without performing.
The setting of the search range includes information including a reference index for specifying a processed picture that can be referred to, the size of the search area in the reference index, and the center position shift amount of the search area in the reference index. The encoding apparatus according to claim 24, wherein the search range is set using.
The coding apparatus according to claim 28, wherein the size of the search area is switched according to the total number of the reference indexes.
The encoding apparatus according to claim 28, wherein the size of the search area is set such that the sum of the search areas in the reference index is equal to or less than a specific value.
An upper limit value of the total number of the reference index and the size of the search area or the total sum of the search area is defined in association with the profile value or the level value,
The encoding apparatus according to claim 28, wherein the total number of reference indexes and the size of the search area are set so as to be a value equal to or less than the upper limit value according to a profile value or a level value assigned to a target stream.
The coding apparatus according to claim 28, wherein a plurality of the reference indexes are associated with one referenceable processed picture.
The reference index for specifying the referable processed picture and the information for specifying the size of the search area are encoded in a sequence header area, a picture header area, a slice header area, or a side information area. Coding device as described.
The coding device according to claim 28, wherein the total number of reference indexes and the size of the search area are switched according to the processing capability of the decoding device.
The coding apparatus according to claim 28, wherein the total number of reference indexes and the size of the search area are switched according to a profile value or a level value assigned to a target stream.
The coding apparatus according to claim 28, wherein the total number of reference indexes and the size of the search area are switched according to the size of a target picture.
Two methods, a method of deriving the center position shift amount of the search area for each first processing unit, and a method of setting a common value to all first processing units belonging to the target picture or target slice The coding apparatus according to claim 28, wherein the coding unit is switched for each target picture.
The encoding apparatus according to claim 37, wherein information for specifying which of the two methods is used is encoded in a picture header area or a slice header area.
Circuit,
With memory,
The circuit uses the memory to
Set a search range commonly used in the first processing unit,
For the second processing unit using inter prediction among the plurality of second processing units included in the first processing unit, reference to pixels outside the search range is restricted, and decoding is performed using pixels within the search range Decoding device that performs processing.
The first processing unit is a block unit composed of one or more second processing units which is a basic division unit of a picture, or a predefined size composed of one or more second processing units 40. The decoding apparatus according to claim 39, wherein the unit is a block unit of a unit.
In the setting of the search range, the search range is set using information including a processed picture to which reference can be made, a size of a search area in the processed picture, and a center position shift amount of the search area in the processed picture. The decoding device according to claim 39.
42. The decoding device according to claim 41, wherein the size of the search area is switched according to the number of the reference-processed processed pictures.
42. The decoding apparatus according to claim 41, wherein the size of the search area is set such that the sum of the search areas in the referenceable processed picture is less than or equal to a specific value.
An upper limit value of the number of referable processed pictures and the size of the search area or the sum of the search areas is defined in association with a profile value or a level value.
42. The number of referable processed pictures and the size of the search area are set so as to be a value equal to or less than the upper limit value according to a profile value or a level value assigned to a target stream. Decoding device.
Information indicating that the inter prediction mode requiring the pixels outside the search range is not selected in all the second processing units included in the first processing unit, a sequence header area, a picture header area, and a slice header The decoding apparatus according to claim 39, wherein the decoding is performed from the area or the auxiliary information area.
The decoding device according to claim 41, wherein the center position shift amount of the search area is a shift amount between a position of a target first processing unit in a target picture and a position of the search area in a processed picture to be referred to.
42. The decoding apparatus according to claim 41, wherein the shift amount of the center position of the search area is derived for each first processing unit.
The center position shift amount of the search area is derived using a motion vector assigned to a second processing unit included in a processed first processing unit located in the spatial or temporal periphery of the target first processing unit. The decryption device according to Item 41.
The decoding device according to claim 48, wherein the processed first processing unit is a processed first processing unit other than the first processing unit in which the processing order is immediately before the target first processing unit.
As the center position shift amount of the search area, a common value is set to all the first processing units included in the target picture or target slice,
42. The decoding apparatus according to claim 41, wherein the information for specifying the common value is decoded from a picture header area or a slice header area, and the common value is specified.
When the position of the search range is specified, transfer of reference pixel data of the search range set for the target first processing unit is started from a memory storing image data of a processed picture, 40. The decryption apparatus according to claim 39, wherein processing of the target first processing unit is started after transfer is completed.
Reference pixel data of the search range set for a target first processing unit from a memory storing image data of a processed picture without waiting for processing of the first processing unit whose processing order is immediately before 50. The decryption apparatus according to claim 49, wherein transfer of is started.
Among reference pixel data of the search range set for the target first processing unit, except for reference pixel data of an area overlapping the search range set for the already processed first processing unit The decoding apparatus according to claim 39, wherein the reference pixel data is transferred from a memory.
Among the one or more second processing units included in the first processing unit, reference to pixels outside the search range is restricted with respect to the second processing unit using the FRUC mode, and pixels within the search range are selected. 40. The decoding apparatus according to claim 39, wherein the decoding process is performed.
In the FRUC mode,
The candidate motion vectors with reference to the pixels outside the search range are excluded from evaluation targets from a plurality of candidate motion vectors derived from the motion vector of the processed block,
The decoding apparatus according to claim 54, wherein cost evaluation is performed on candidate motion vectors after exclusion.
In the removal of the candidate motion vector, a candidate motion vector requiring a pixel outside the search range is further excluded from the evaluation target in another process related to prediction image generation applied after performing the FRUC process. 55. The decoding device according to 55.
In the FRUC mode, another process related to predicted image generation applied after the FRUC process is performed, and there is the other process requiring a pixel outside the search range, the other process is performed. The decoding device according to claim 55, wherein the prediction image is generated without performing.
The setting of the search range includes information including a reference index for specifying a processed picture that can be referred to, the size of the search area in the reference index, and the center position shift amount of the search area in the reference index. The decoding device according to claim 54, wherein the search range is set using.
The decoding device according to claim 58, wherein the size of the search area is switched according to the total number of the reference indexes.
The decoding device according to Claim 58, wherein the size of the search area is set such that the sum of the search areas in the reference index is less than or equal to a specific value.
An upper limit value of the total number of the reference index and the size of the search area or the total sum of the search area is defined in association with the profile value or the level value,
The decoding apparatus according to claim 58, wherein the total number of the reference indexes and the size of the search area are set so as to be a value equal to or less than the upper limit value according to a profile value or a level value assigned to a target stream.
The reference index for specifying the referenceable processed picture and the information for specifying the size of the search area are decoded from the sequence header area, the picture header area, the slice header area or the auxiliary information area, and the reference index The decoding apparatus according to claim 58, wherein the size of the search area is specified.
Two methods, a method of deriving the center position shift amount of the search area for each first processing unit, and a method of setting a common value to all first processing units belonging to the target picture or target slice The decoding device according to claim 58, wherein:
The decoding apparatus according to claim 63, wherein information for specifying which of the two methods is to be used is decoded from a picture header area or a slice header area, and which of the two methods is to be used.
Set a search range commonly used in the first processing unit,
For the second processing unit using inter prediction among the one or more second processing units included in the first processing unit, the reference of the pixels outside the search range is restricted, and the pixels in the search range are referred to Coding method to perform coding processing.
Set a search range commonly used in the first processing unit,
For the second processing unit using inter prediction among the plurality of second processing units included in the first processing unit, reference to pixels outside the search range is restricted, and decoding is performed using pixels within the search range Decryption method to process.