WO2019146718A1 - Coding device, decoding device, coding method, and decoding method - Google Patents

Abstract

A coding device (100) is provided with a circuit and a memory. The circuit uses the memory to, in an inter prediction mode in which a block to be processed is divided into sub-blocks and motion compensation is performed sub-bock by sub-block, switch the horizontal and vertical lengths of the sub-blocks on the basis of the size of the block to be processed and perform coding processing.

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.

A video coding standard called HEVC (High-Efficiency Video Coding) is standardized by JCT-VC (Joint Collaborative Team on Video Coding).

There is a need for further improvements in such encoding and decoding techniques.

Therefore, the present disclosure aims to provide an encoding device, a decoding device, an encoding method, or a decoding method that can realize further improvement.

An encoding apparatus according to an aspect of the present disclosure includes a circuit and a memory, and the circuit divides the processing target block into sub blocks using the memory and performs motion compensation in units of sub blocks. In the prediction mode, encoding processing is performed by switching the horizontal and vertical lengths of the sub block based on the size of the processing target block.

A decoding device according to an aspect of the present disclosure includes a circuit and a memory, and the circuit divides the processing target block into sub blocks using the memory and performs motion compensation in units of sub blocks. In the mode, the decoding process is performed by switching the horizontal and vertical lengths of the sub block based on the size of the processing target block.

Note that these general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer readable CD-ROM, a system, a method, an integrated circuit, a computer program And any combination of recording media.

The present disclosure can provide a coding device, a decoding device, a coding method or a decoding method that can realize further improvement.

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 showing a first example of the inter prediction process in the first embodiment. FIG. 12 is a diagram for describing a specific example of the size of the sub block obtained by dividing the processing target block. FIG. 13 is a diagram for explaining an ATM VP mode which is an example of the sub book unit merge mode. FIG. 14 is a diagram for describing an STMVP mode which is another example of the sub book unit merge mode. FIG. 15 is an overall configuration diagram of a content supply system for realizing content distribution service. FIG. 16 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 17 is a diagram illustrating an example of a coding structure at the time of scalable coding. FIG. 18 is a diagram showing an example of a display screen of a web page. FIG. 19 is a view showing an example of a display screen of a web page. FIG. 20 is a diagram illustrating an example of a smartphone. FIG. 21 is a block diagram showing a configuration example of a smartphone.

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 processing and / or configuration described in each aspect of the present disclosure can be applied, and the processing and / or configuration described in each aspect of the present disclosure Can also be implemented in an encoding apparatus and a decoding apparatus different from those in 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) Components corresponding to the components described in each aspect of the present disclosure among a plurality of components configuring the encoding apparatus or the decoding apparatus with respect to the encoding apparatus or the decoding apparatus according to the first embodiment With the components described in each aspect of the present disclosure (2) With respect to the encoding device or the decoding device of the first embodiment, one of a plurality of components constituting the encoding device or the decoding device The configuration elements corresponding to the components described in each aspect of the present disclosure are added in each aspect of the present disclosure after arbitrary changes such as addition, replacement, deletion, etc. of functions or processing to be performed on components of the part are performed. Replacing the component to be described (3) With respect to the method implemented by the encoding device or the decoding device of the first embodiment, addition of a process and / or part of a plurality of processes included in the method processing Replacing any processing corresponding to the processing described in each aspect of the present disclosure with the processing described in each aspect of the present disclosure (4) Some components of the plurality of components constituting the encoding device or the decoding device will be the components described in each aspect of the present disclosure, some of the functions of the components described in each aspect of the present disclosure In combination with a component that carries out a part of the process performed by the component described in each aspect of the present disclosure, or (5) the encoding apparatus or the decoding apparatus according to the first embodiment A component having a part of functions provided by a part of a plurality of components to be selected, or a configuration of a part of a plurality of components constituting the encoding apparatus or the decoding apparatus of the first embodiment Element performs The components that perform part of the process are the components described in each aspect of the present disclosure, the components provided with a part of the functions of the components described in each aspect of the present disclosure, or (6) A plurality of methods included in a method implemented 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 with the processing described in each aspect of the present disclosure (7) A method implemented by the encoding apparatus or the decoding apparatus according to the first embodiment Performing some of the plurality of processes included in the above 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, the process may be implemented in an apparatus used for a purpose different from that of the moving picture / image coding apparatus or the moving picture / image decoding apparatus disclosed in the first embodiment, or the processing and / or configuration described in each aspect. 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 conversion unit 106 performs reconversion 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. 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 to switch whether to apply the OBMC process according to the value and performs 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, with respect to the current block, the reconstructed image of the left adjacent region and / or the upper adjacent encoded region, and the equivalent in the encoded reference picture (Ref 0) specified by the candidate MV 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, areas 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.

In addition, in the encoding apparatus and the decoding apparatus, the outline of the process described here is basically common.

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 regions 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]
Here, an example of the inter prediction processing in the inter prediction units 126 and 218 will be described with reference to the drawings. FIG. 11 is a flowchart showing a first example of the inter prediction process in the first embodiment. In addition, since the inter prediction unit 218 performs the same processing as the inter prediction unit 126, in the present example, the description of the inter prediction unit 218 is appropriately omitted.

The inter prediction unit 126 can select a prediction mode from a plurality of modes (normal mode, merge mode, affine mode, etc.), and derives a motion vector (MV) using the selected prediction mode. At this time, the plurality of prediction modes are a first type of prediction mode (normal mode, block unit merge mode, etc.) for deriving a motion vector (MV) in prediction block units, and MV in sub block units obtained by further dividing the prediction block. Are roughly divided into a second type of prediction mode (sub-block unit merge mode, affine mode, etc.) for deriving. As an example of the sub-block unit merge mode, there are an ATMVP (Advanced Temporal Motion Vector Prediction) mode, an STMVP (Spatial-Temporal Motion Vector Prediction) mode, and the like.

In loop processing on a prediction block basis (S101 to S112), first, the inter prediction unit 126 determines inter prediction mode information of a prediction block (S102). Here, when the inter prediction mode is the normal mode included in the first type of prediction mode (the normal mode of S102), the inter prediction unit 126 derives the MV for the normal mode in block units (S103). When the inter prediction mode is a merge mode in block units included in the first type of prediction mode (merge mode (block) in S102), the inter prediction unit 126 derives MV for merge mode in block units. (S104). The inter prediction unit 126 generates a prediction image of a prediction block by performing motion compensation (MC) processing in units of blocks using the MV derived in step S103 or step S104 (S105).

On the other hand, when the inter prediction mode is the second type of prediction mode for deriving MV in units of sub blocks (merge mode (sub block) and affine mode in S102), the inter prediction unit 126 determines the size of the prediction block to be processed. Then, the sub-block size is determined according to (S106), and the prediction block is divided into sub-blocks at that size. The block size is defined by the horizontal and vertical lengths of the block. Details of the determination of the sub block size in step S106 will be described later.

Thereafter, the inter prediction unit 126 derives an MV for merge mode in a sub-block unit or an MV for affine mode in a sub-block unit (S107, S108). Then, in loop processing in units of subblocks (S109 to S111), the inter prediction unit 126 performs MC processing in units of subblocks using the MV derived in step S107 or step S108 (S110). Generate a predicted image of

Here, an example of the method of determining the sub block size in step S106 of FIG. 11 will be described.

The inter prediction unit 126 determines, for example, the horizontal and vertical lengths of the sub block based on the following formula.

Sub block size (horizontal) = MAX (M1, predicted block size (horizontal) / 2 ^N1 )

Sub block size (vertical) = MAX (M2, predicted block size (vertical) / 2 ^N2 )

Here, M1 and M2 are a first predetermined value and a second predetermined value, respectively, and both are predetermined integers of 1 or more. Further, N1 and N2 are an index of the first power operation and an index of the second power operation, respectively, and both are predetermined integers of 0 or more.

Specifically, the inter prediction unit 126 first calculates the quotient of the first division that divides the predicted block size in the horizontal direction by the first power operation (2 ^N1 ). Here, the base of the first power operation is 2, and the exponent of the first power operation is N1. Then, if the calculated quotient of the first division is M1 or more, the inter prediction unit 126 sets the calculated quotient of the first division as the sub-block size in the horizontal direction. On the other hand, if the calculated quotient of the first multiplication is smaller than M1, the inter prediction unit 126 sets M1 as the horizontal sub-block size.

Similarly, the inter prediction unit 126 calculates the quotient of the second division that divides the predicted block size in the vertical direction by the second power operation (2 ^N2 ). Here, the base of the second power operation is 2, and the exponent of the second power operation is N2. Then, if the calculated quotient of the second division is M2 or more, the inter prediction unit 126 sets the calculated quotient of the second division as the vertical sub-block size. On the other hand, if the calculated quotient of the second division is smaller than M2, the inter prediction unit 126 sets M2 as the vertical sub-block size.

Note that N1 and N2 may be the same value or different values. Similarly, M1 and M2 may have the same value or different values.

Note that M1 and M2 may be determined based on the minimum block size (for example, 4 × 4 pixels) that can perform motion compensation processing. For example, M1 and M2 may be determined as the horizontal size (for example, 4 pixels) and the vertical size (for example, 4 pixels) of the minimum block size allowed for motion compensation processing, respectively.

In FIG. 11, the sub-block size determination (S106) is performed for both sub-block unit merge mode and affine mode, but the sub-block size determination may be performed only in one of the modes. Good. For example, determination of subblock size is performed in merge mode in units of subblocks, and in affine mode, a prediction block may be always divided into subblocks of fixed size without determination of subblock size, or vice versa It may be Also, the determination of the sub-block size may be similarly performed for the merge mode of the sub-block unit and the second type prediction mode for deriving the MV in sub-block units other than the affine mode.

Note that the process flow of FIG. 11 is an example, and part of the processes described may be removed or processes not described may be added.

[Specific example of sub block size]
FIG. 12 is a diagram for describing a specific example of the size of the sub block obtained by dividing the processing target block.

In (Example 1), 4 is given as both M1 and M2, and 3 is given as both N1 and N2.

As shown in (a), when the prediction block size is 32 × 32 pixels, the prediction block is divided into 4 × 4 pixel sub blocks. At this time, the prediction block and the sub-block both have a square of 1: 1 in width: length.

As shown in (b), when the prediction block size is 64 × 32 pixels, the prediction block is divided into subblocks of 8 × 4 pixels. At this time, the prediction block and the sub-block both have a rectangle of 2: 1 horizontal: vertical.

As shown in (c), when the prediction block size is 16 × 32 pixels, the prediction block is divided into subblocks of 4 × 4 pixels. At this time, the prediction block is a rectangle of 1: 2 in horizontal: vertical, but the sub-block is a square of 1: 1 in horizontal: vertical.

In (Example 2), 4 is given as both M1 and M2, and 2 is given as both N1 and N2.

As shown in (d), when the prediction block size is 32 × 32 pixels, the prediction block is divided into sub blocks of 8 × 8 pixels. At this time, the prediction block and the sub-block both have a square of 1: 1 in width: length.

As shown in (e), when the prediction block size is 64 × 32 pixels, the prediction block is divided into subblocks of 16 × 8 pixels. At this time, the prediction block and the sub-block both have a rectangle of 2: 1 horizontal: vertical.

As shown in (f), when the prediction block size is 16 × 32 pixels, the prediction block is divided into 4 × 8 pixel sub blocks. At this time, both of the prediction block and the sub-block become a rectangle having a width: height of 1: 2.

In general, when an image to be processed has a highly correlated feature in a particular direction, a prediction block having a long shape in the particular direction tends to be selected. Therefore, by determining the size of the sub-blocks to be long in the specific direction, there is a high possibility that they can be divided into sub-blocks in which the coding efficiency is optimal. In particular, when N1 and N2 are equal, there is a high possibility that the aspect ratio of the prediction block and the aspect ratio of the sub-blocks can be equal, so that highly efficient encoding matched to the feature of the image can be promoted.

Also, by setting to divide into relatively small sub-blocks as in (Example 1), although the processing amount increases, it is possible to select the MV in smaller sub-blocks, thus improving the coding efficiency. Chances of being Also, by setting to divide into relatively large sub-blocks as in (Example 2), although the coding efficiency is lowered, the MV selection and motion compensation processing are performed in units of larger sub-blocks. There is a high possibility that the throughput can be reduced.

If the values of N1 and N2 increase, the sub-block size is reduced. Also, if the values of M1 and M2 decrease, smaller subblock sizes are allowed. That is, increasing N1 and N2 and / or decreasing M1 and M2 divides the prediction block into smaller sub-blocks. On the other hand, if N1 and N2 are decreased and / or M1 and M2 are increased, the prediction block is divided into larger sub-blocks.

Although an example in which the vertical and horizontal lengths of the sub-blocks are determined based on the vertical and horizontal lengths of the prediction block to be processed is shown, the present invention is not limited to this example. The vertical and horizontal lengths of the sub blocks may be determined based on only one of the two.

Also, the vertical and horizontal lengths of the sub-blocks may be determined based on the ratio of vertical and horizontal lengths rather than the absolute values of vertical and horizontal lengths of the prediction block to be processed. For example, the vertical and horizontal lengths of the sub-blocks may be determined such that the ratio of vertical and horizontal lengths of the prediction block and the vertical and horizontal lengths of the sub-blocks are the same.

[Variation of first example of inter prediction processing]
In addition, the entropy coding unit 110 of the coding apparatus 100 of the information related to M1, M2, N1 and N2 in FIGS. 11 and 12 is a sequence header area, a picture header area, a slice header area or auxiliary information of a coded bit stream. It may be encoded in the area. In this case, the entropy decoding unit 202 of the decoding device 200 may decode the information on M1, M2, N1, and N2 from those regions.

For example, the coding apparatus 100 switches the values of M1, M2, N1, and N2 according to the processing capacity of the coding apparatus 100 and the processing capacity of the decoding apparatus 200 to which the coding bit stream is transmitted from the coding apparatus 100. May be That is, the encoding apparatus 100 may determine the values of M1, M2, N1, and N2 based on the processing capabilities of the encoding apparatus 100 and the decoding apparatus 200. For example, if the processing capability is high, the encoding apparatus 100 sets the values of M1, M2, N1, and N2 so that they can be divided into small subblocks because many processes can be performed in a fixed processing time. May be On the other hand, if the processing capability is low, encoding apparatus 100 can set many values of M1, M2, N1, and N2 so that they can be divided into large subblocks because they can not perform many processings in a fixed processing time. Good.

Also, the coding apparatus 100 may switch the values of M1, M2, N1, and N2 according to the profile or level information assigned to the coded bit stream. That is, the encoding apparatus 100 may determine the values of M1, M2, N1 and N2 based on the profile or level information. For example, in a profile and level assuming that decoding apparatus 200 has sufficient processing capability, encoding apparatus 100 sets the values of M1, M2, N1, and N2 so as to be divided into small subblocks. It is also good. On the other hand, in the profile and level assuming that the decoding apparatus 200 has insufficient processing power, the encoding apparatus 100 sets the values of M1, M2, N1 and N2 so as to be divided into large subblocks. May be

Also, the coding apparatus 100 may switch the values of M1, M2, N1, and N2 according to the size of the current picture to be coded. That is, the encoding apparatus 100 may determine the values of M1, M2, N1, and N2 based on the size of the current picture to be encoded. For example, when the picture size is small, the encoding apparatus 100 may set the values of M1, M2, N1, and N2 so as to be divided into small subblocks so as to be able to follow finer motion. On the other hand, when the picture size is large, the encoding apparatus 100 divides the values of M1, M2, N1, and N2 so as to be divided into large subblocks so as not to be unnecessarily dragged by local fine motions. It may be set.

The information on M1, M2, N1 and N2 to be encoded into the bit stream may not be a signal of information strictly indicating them, and may be encoded as a signal having another meaning. For example, by directly associating information on M1, M2, N1, and N2 with profiles and levels in advance and defining them in advance, M1, M2, N1, and N2 can be identified with only signals indicating the profiles and levels.

Also, information indicating the values of M1, M2, N1 and N2 themselves may be encoded, or information indicating a difference value from the values of M1, M2, N1 and N2 defined in advance in a standard etc. may be encoded. It is also good.

In the decoding apparatus 200, the process of encoding a signal necessary for the process into a stream is replaced with the process of decoding from a stream, but the inter prediction process described with reference to FIG. 11 is basically common. At this time, in the decoding device 200, the inter prediction unit 218 performs an inter prediction process instead of the inter prediction unit 126.

[Effect of the first example of inter prediction processing]
According to the configuration described with reference to FIGS. 11 and 12, encoding apparatus 100 and decoding apparatus 200 divide the processing target block (prediction block) into sub blocks and perform motion compensation in units of sub blocks. In the prediction mode, encoding / decoding processing can be performed by switching the horizontal and vertical lengths of the sub block based on the size of the processing target block. That is, the encoding apparatus 100 and the decoding apparatus 200 can perform motion compensation on subblocks of variable sizes depending on the size of the processing target block.

This makes it possible to divide into the optimal sub-block size in the second type of prediction mode. As a result, it is possible to suppress an increase in processing amount due to division into unnecessarily fine subblocks, and a decrease in coding performance due to an excessively large subblock.

Further, according to the above configuration, the encoding apparatus 100 and the decoding apparatus 200 determine the horizontal length of the sub block based on the quotient of the first division dividing the horizontal length of the processing target block by the first power operation. It can be decided. At this time, 2 can be used as the base of the first power operation, and a predetermined integer greater than or equal to 0 can be used as the index N1 of the first power operation. Similarly, the encoding apparatus 100 and the decoding apparatus 200 can determine the vertical length of the sub-block based on the quotient of the second division that divides the vertical length of the processing target block by the second power operation. . At this time, 2 can be used as the base of the second power operation, and a predetermined integer greater than or equal to 0 can be used as the exponent N2 of the second power operation.

Thus, using the two parameters N1 and N2, the horizontal and vertical lengths of the sub-block can be increased as the size of the block to be processed is larger, and the smaller the size of the block to be processed is, the horizontal direction of the sub-block And the vertical length can be reduced. As a result, when the size of the processing target block is small, the encoding device 100 and the decoding device 200 can realize small sub-blocks so as to be able to follow finer motion. On the other hand, when the size of the processing target block is large, the encoding device 100 can realize a large sub-block so as not to be dragged excessively by the local fine motion.

Further, according to the above configuration, when the quotient of the first division is smaller than the first predetermined value M1, the encoding device 100 and the decoding device 200 determine the horizontal length of the sub block as the first predetermined value M1. If the quotient of the first division is greater than or equal to the first predetermined value M1, the horizontal length of the sub block can be determined as the quotient of the first division. Similarly, when the quotient of the second division is smaller than the second predetermined value M2, the encoding device 100 and the decoding device 200 determine the vertical length of the sub block as the second predetermined value M2, and the second division The vertical length of the sub block can be determined as the quotient of the second division when the quotient of is equal to or greater than the second predetermined value M2.

This can prevent the lateral and vertical lengths of the subblocks determined using N1 and N2 from being too small, and can suppress unnecessary increases in throughput.

Further, according to the above configuration, the encoding device 100 and the decoding device 200 can determine the first predetermined value M1 and the second predetermined value M2 based on the minimum block size of usable motion compensation.

This can prevent the horizontal and vertical lengths of the sub block determined using N1 and N2 from becoming smaller than the minimum block size of motion compensation. That is, the horizontal and vertical lengths of the sub-blocks can be made variable within the range satisfying the condition of the minimum block size of motion compensation.

Further, according to the above configuration, the encoding apparatus 100 can use the sequence header to specify information for specifying the first predetermined value M1, the second predetermined value M2, the exponent N1 of the first operation and the exponent N2 of the second operation. It can be encoded into an area, a picture header area, a slice header area or a side information area. Then, the decoding device 200 includes information for specifying the first predetermined value M1, the second predetermined value M2, the exponent N1 of the first power operation and the exponent N2 of the second power operation, a sequence header region, a picture header region, It is possible to decode from the slice header area or the side information area.

Thus, regardless of how M1, M2, N1, and N2 are determined by the coding apparatus 100, the decoding apparatus 200 uses the same M1, M2, N1, and N2 as the coding apparatus 100 to execute sub-block horizontal and Vertical length can be determined.

Further, according to the above configuration, the encoding device 100 can set the first predetermined value M1 and the second predetermined value M2 according to the processing capability of the encoding device 100 and the processing capability of the decoding device 200 corresponding to the encoding device 100. , The exponent N1 of the first power operation and the exponent N2 of the second power operation can be switched and encoded. That is, the encoding device 100 can change the values of M1, M2, N1 and N2 depending on the processing capabilities of the encoding device 100 and the decoding device 200, and such M1, M2, N1 and N2 Information for identification can be encoded in the bitstream.

Thereby, the values of M1, M2, N1 and N2 for realizing the horizontal and vertical lengths of the sub-blocks according to the processing capabilities of the encoding device 100 and the decoding device 200 can be encoded in the bitstream. it can. As a result, it is possible to avoid that the sub-block size is too small, and an excessive amount of processing is required for the processing capacity of the encoding apparatus 100 and the decoding apparatus 200.

Further, according to the above configuration, the encoding apparatus 100 can set the first predetermined value M1, the second predetermined value M2, the exponent N1 of the first operation according to the profile value or the level value assigned to the encoding target stream. And the exponent N2 of the second power operation can be switched and encoded. That is, encoding apparatus 100 can change the values of M1, M2, N1, and N2 depending on the profile value or the level value, and information for identifying such M1, M2, N1, and N2 can be obtained. It can be encoded in the bitstream.

Thereby, the values of M1, M2, N1 and N2 for realizing the size of the sub block according to the profile value or the level value can be encoded in the bitstream. As a result, it is possible to realize the size of the sub block according to the processing capability of the decoding device 200 assumed by the profile value or the level value.

Further, according to the above configuration, the encoding device 100 can calculate the first predetermined value M1, the second predetermined value M2, the exponent N1 of the first operation, and the second operation according to the size of the encoding target picture. The exponent N2 can be switched and encoded. That is, encoding apparatus 100 can change the values of M1, M2, N1 and N2 depending on the size of the picture to be encoded, and for identifying such M1, M2, N1 and N2. Information can be encoded into the bitstream.

Thereby, the values of M1, M2, N1, and N2 for realizing the size of the sub block according to the size of the picture to be encoded can be encoded in the bitstream. For example, when the picture size is small, the encoding apparatus 100 can encode the values of M1, M2, N1 and N2 for realizing a small sub-block so as to follow finer motion. On the other hand, when the picture size is large, the encoding apparatus 100 encodes the values of M1, M2, N1 and N2 for realizing a large sub-block so as not to be unnecessarily dragged by local fine motions. can do.

[Description of ATMVP mode]
Next, the ATM VP mode will be briefly described. The ATM VP mode is an example of a merge mode for deriving a motion vector of a processing target block using a motion vector of a reference block located at the same position as the processing target block included in a picture different from the picture to which the processing target block belongs. . FIG. 13 is a diagram for explaining an ATM VP mode which is an example of the sub book unit merge mode.

In the merge mode, one candidate is selected from the MV candidate list generated with reference to the processed block, and the MV of the processing target block is determined. At this time, in the ATM VP mode, the inter prediction units 126 and 218 derive one candidate registered in the MV candidate list as follows.

In the ATMVP mode, first, referring to the MV (MV0) of the neighboring MV reference block 1300 adjacent to the lower left of the processing target block 1100 in the processing target picture 1000, the coded time MV reference picture 2000 specified by MV0 is referred to. The time MV reference block 2100 associated with the process target block 1100 is identified. Next, for each sub-block in the processing target block 1100, the MV used at the time of encoding the region (for example, the region 2200) corresponding to the sub-block (for example, the sub-block 1200) in the temporal MV reference block is specified. Then, scaling is performed according to the time interval with reference to the specified MV to obtain the MV of each sub block.

Although the block adjacent to the lower left is used as the block referring to MV0 in FIG. 13, other blocks may be used.

Moreover, although the process in encoding was demonstrated here, it becomes the same process also in decoding.

[Description of STMVP mode]
Next, the STMVP mode will be briefly described. The STMVP mode is an example of a merge mode in which a motion vector of a processing target block is derived using motion vectors of adjacent blocks adjacent to the processing target block. FIG. 14 is a diagram for describing an STMVP mode which is another example of the sub book unit merge mode.

In the merge mode, one candidate is selected from the MV candidate list generated with reference to the processed block, and the MV of the processing target block is determined. At this time, in the STMVP mode, the inter prediction units 126 and 218 derive one candidate to be registered in the MV candidate list as follows.

In the STMVP mode, first, a temporal MV reference block 3100 located at the same position as the processing target block 1100 in the encoded temporal MV reference picture 3000 is specified. Next, for each sub-block in the block to be processed 1100, the MV (MV_up) of a block (for example, block 1400) spatially adjacent to the sub-block (for example, sub-block 1200) is spatially adjacent to the left. The MV (MV_left) of the block (eg, block 1500) and the MV (MV_col) used when encoding the temporal MV reference block 3100 are identified. In the example of FIG. 14, the MV of the block 3200 located at the lower right with respect to the position of the target sub block 1200 is used as the MV_col. And MV of each subblock is acquired by computing the average of the value which scaled up MV_up, MV_left, and MV_col according to a time interval.

Although the MV of the block (for example, block 3200) located at the lower right with respect to the position of the target sub block (for example, sub block 1200) is used as MV_col in FIG. 14, the MV of the block at other positions is used. May be used.

Further, in FIG. 14, the MV of each sub-block is obtained by calculating the average of MV_up, MV_left, and MV_col, but other surrounding MVs may be used, or representative MV may be calculated by methods other than average. You may acquire MV of each subblock by doing.

Moreover, although the process in encoding was demonstrated here, it becomes the same process also in decoding.

This example may be implemented in combination with at least a part of other aspects in the present disclosure. In addition, part of the processing described in the flowchart of this example, part of the configuration of the apparatus, and part of the syntax 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. 15 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 the content supply system ex100, 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 service provider ex102 or the communication network ex104 and the base stations ex106 to ex110 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, or a terminal in an airplane ex117 that can decode the 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. to perform distributed processing. 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 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. 17, meta-information is stored using a data storage structure different from pixel data, such as an 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. 18 is a diagram showing an example of a display screen of a web page in the computer ex111 and the like. FIG. 19 is a diagram illustrating an example of a display screen of a web page in the smartphone ex115 or the like. As shown in FIGS. 18 and 19, 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 decreases if the shooting time is too long, and the server moves not only the scenes with low importance as described above but also the motion so as to be the content 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 is also applicable to 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. 20 is a diagram showing the smartphone ex115. FIG. 21 is a diagram illustrating an exemplary 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, Specify a user, a memory unit ex467 capable of storing encoded video or still image, recorded voice, received video or still image, encoded data such as mail, or decoded data, and various networks and networks And a slot unit ex464 that is an interface unit with the SIM ex 468 for authenticating access to 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 the moving picture linked from the display unit ex 458 via the display control unit ex 459 An image or a still image included in the 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.

Here, although the smartphone ex115 is described as an example, in addition to a transmission / reception terminal having both an encoder and a decoder as a terminal, it is referred to as a transmitting terminal having only the encoder and a receiving terminal having only the decoder. There are three possible implementation types. 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, television receivers, digital video recorders, car navigation systems, mobile phones, digital cameras, digital video cameras, 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 200 Decoding device 202 Entropy decoding unit

Claims (27)

1. Circuit,
   With memory,
   The circuit uses the memory to
   In an inter prediction mode in which a block to be processed is divided into subblocks and motion compensation is performed in units of subblocks, encoding is performed by switching the horizontal and vertical lengths of the subblocks based on the size of the block to be processed.
   Encoding device.
2. The horizontal length of the sub block is determined based on the horizontal length of the process target block, and the vertical length of the sub block is determined based on the vertical length of the process target block ,
   The encoding device according to claim 1.
3. The inter prediction mode in which motion compensation is performed in units of sub blocks is a merge mode in which a motion vector is derived using a motion vector of an adjacent block adjacent to the processing target block.
   The encoding device according to claim 1 or 2.
4. In the inter prediction mode in which motion compensation is performed in units of sub blocks, a motion vector is calculated using a motion vector of a reference block located at the same place as the processing target block included in a picture different from the picture to which the processing target block belongs. Merge mode to derive,
   The encoding device according to claim 1 or 2.
5. The inter prediction mode in which motion compensation is performed in units of sub blocks is an affine mode that derives a motion vector using an affine transformation process,
   The encoding device according to claim 1 or 2.
6. The horizontal length of the sub block is determined based on the quotient of the first division dividing the horizontal length of the processing target block by the first power, and the base of the first power is 2; The exponent of the first power operation is a predetermined integer greater than or equal to 0,
   The vertical length of the sub block is determined based on the quotient of the second division dividing the vertical length of the processing target block by the second power, and the base of the second power is 2; The exponent of the second power operation is a predetermined integer greater than or equal to 0,
   The encoding apparatus according to any one of claims 1 to 5.
7. The exponent of the first power operation has a value different from the exponent of the second power operation,
   The encoding device according to claim 6.
8. When the quotient of the first division is smaller than a first predetermined value, the horizontal length of the sub block is determined as the first predetermined value,
   When the quotient of the first division is greater than or equal to the first predetermined value, the horizontal length of the sub-block is determined as the quotient of the first division,
   When the quotient of the second division is smaller than a second predetermined value, the vertical length of the sub block is determined as the second predetermined value,
   When the quotient of the second division is greater than or equal to the second predetermined value, the vertical length of the sub block is determined as the quotient of the second division.
   The encoding device according to claim 6 or 7.
9. The first predetermined value is different from the second predetermined value,
   The encoding device according to claim 8.
10. The first predetermined value and the second predetermined value are determined based on the smallest block size of usable motion compensation.
    The encoding device according to claim 8 or 9.
11. Information for specifying the first predetermined value, the second predetermined value, the index of the first power operation and the index of the second power operation, a sequence header area, a picture header area, a slice header area or an auxiliary information area Encode to
    The encoding device according to any one of claims 8 to 10.
12. The first predetermined value, the second predetermined value, the exponent of the first operation, and the second operation according to the processing capability of the encoding device and the processing capability of the decoding device corresponding to the encoding device Switch exponents and encode,
    An encoding apparatus according to claim 11.
13. The first predetermined value, the second predetermined value, the exponent of the first power operation, and the exponent of the second power operation are switched and encoded according to the profile value or the level value assigned to the encoding target stream ,
    An encoding apparatus according to claim 11.
14. The first predetermined value, the second predetermined value, the exponent of the first power operation, and the exponent of the second power operation are switched and encoded according to the size of the picture to be encoded.
    An encoding apparatus according to claim 11.
15. In an inter prediction mode in which a block to be processed is divided into subblocks and motion compensation is performed in units of subblocks, encoding is performed by switching the horizontal and vertical lengths of the subblocks based on the size of the block to be processed.
    Encoding method.
16. Circuit,
    With memory,
    The circuit uses the memory to
    In an inter prediction mode in which a processing target block is divided into sub blocks and motion compensation is performed in units of sub blocks, decoding processing is performed by switching the horizontal and vertical lengths of the sub blocks based on the size of the processing target block.
    Decoding device.
17. The horizontal length of the sub block is determined based on the horizontal length of the process target block, and the vertical length of the sub block is determined based on the vertical length of the process target block ,
    The decoding device according to claim 16.
18. The inter prediction mode in which motion compensation is performed in units of sub blocks is a merge mode in which a motion vector is derived using a motion vector of an adjacent block adjacent to the processing target block,
    The decoding device according to claim 16 or 17.
19. In the inter prediction mode in which motion compensation is performed in units of sub blocks, a motion vector is derived using a motion vector of a reference block located at the same place as the processing target block included in a picture different from the picture to which the processing target block belongs. In merge mode,
    The decoding device according to claim 16 or 17.
20. The inter prediction mode in which motion compensation is performed in units of sub blocks is an affine mode that derives a motion vector using an affine transformation process,
    The decoding device according to claim 16 or 17.
21. The horizontal length of the sub block is determined based on the quotient of the first division dividing the horizontal length of the processing target block by the first power, and the base of the first power is 2; The exponent of the first power operation is a predetermined integer greater than or equal to 0,
    The vertical length of the sub block is determined based on the quotient of the second division dividing the vertical length of the processing target block by the second power, and the base of the second power is 2; The exponent of the second power operation is a predetermined integer greater than or equal to 0,
    The decoding device according to any one of claims 16 to 20.
22. The exponent of the first power operation has a value different from the exponent of the second power operation,
    The decoding device according to claim 21.
23. When the quotient of the first division is smaller than a first predetermined value, the horizontal length of the sub block is determined as the first predetermined value,
    When the quotient of the first division is greater than or equal to the first predetermined value, the horizontal length of the sub-block is determined as the quotient of the first division,
    When the quotient of the second division is smaller than a second predetermined value, the vertical length of the sub block is determined as the second predetermined value,
    When the quotient of the second division is greater than or equal to the second predetermined value, the vertical length of the sub block is determined as the quotient of the second division.
    A decoding device according to claim 21 or 22.
24. The first predetermined value is different from the second predetermined value,
    The decoding device according to claim 23.
25. The first predetermined value and the second predetermined value are determined based on the smallest block size of usable motion compensation.
    The decoding device according to claim 23 or 24.
26. Information for specifying the first predetermined value, the second predetermined value, the index of the first power operation and the index of the second power operation, a sequence header area, a picture header area, a slice header area or an auxiliary information area To identify the first predetermined value, the second predetermined value, the exponent of the first power operation, and the exponent of the second power operation,
    The decoding device according to any one of claims 23 to 25.
27. In an inter prediction mode in which a processing target block is divided into sub blocks and motion compensation is performed in units of sub blocks, decoding processing is performed by switching the horizontal and vertical lengths of the sub blocks based on the size of the processing target block.
    Decryption method.

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