WO2019203036A1 - Encoding device, decoding device, encoding method, and decoding method - Google Patents

Abstract

This encoding device (100) performs inter-prediction when encoding an encoding object block constituting a moving image, and is provided with a circuit (160) and a memory (162), wherein in the case when the circuit (160) performs, by using the memory (162), a first process for correcting a prediction image of the encoding object block by utilizing the luminance around the encoding object block and the luminance around a reference block, the circuit (160) performs inter-prediction on the encoding object block without performing one or more processes including a second process for correcting the prediction image using the spatial gradient of the luminance obtained from the reference block.

Description

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

The present disclosure relates to an encoding device that performs inter prediction in encoding of an encoding target block constituting a moving image.

Conventionally, as a standard for encoding moving images, H.C. also called HEVC (High Efficiency Video Coding). H.265 exists (Non-Patent Document 1).

H. 265 (ISO / IEC 23008-2 HEVC) / HEVC (High Efficiency Video Coding)

However, if the processing is not performed efficiently in encoding of moving images, a processing delay may occur.

Therefore, the present disclosure provides an encoding device and the like that can suppress processing delay in encoding moving images.

An encoding apparatus according to an aspect of the present disclosure is an encoding apparatus that performs inter prediction in encoding of an encoding target block constituting a moving image, and includes a circuit and a memory, and the circuit includes the memory When performing the first process of correcting the prediction image of the encoding target block using the luminance around the encoding target block and the luminance around the reference block, the luminance obtained from the reference block The inter prediction of the encoding target block is performed without performing one or more processes including a second process for correcting the predicted image using a spatial gradient.

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

The encoding device and the like according to one aspect of the present disclosure can suppress processing delay in encoding moving images.

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

(Knowledge that became the basis of this disclosure)
For example, the encoding device encodes an image for each block. The encoding apparatus may use inter prediction or intra prediction when encoding an image for each block. When the inter prediction is used for encoding the processing target block, the encoding device specifies a reference block and generates a predicted image of the processing target block with reference to the reference block. Then, the encoding device reduces the code amount by encoding a difference image between the predicted image of the processing target block and the original image of the processing target block.

Also, the decoding device decodes the difference image when decoding the image. Then, the decoding apparatus generates a predicted image of the processing target block with reference to the reference block, and reconstructs the original image by adding the predicted image and the difference image. Thereby, the decoding apparatus can decode an image.

Also, for example, the encoding device and the decoding device may perform correction processing on the predicted image in order to bring the predicted image closer to the original image. The correction process may include a luminance correction process called a LIC (local illumination compensation) process. Specifically, the encoding device and the decoding device derive a luminance correction parameter using the luminance around the processing target block and the luminance around the reference block, and correct the predicted image using the luminance correction parameter. Thereby, the code amount is further reduced.

However, the encoding device and the decoding device cannot use the luminance around the processing target block until the reconstructed image around the processing target block is generated. Therefore, there is a possibility that a delay occurs due to the luminance correction processing or the like.

Thus, for example, an encoding apparatus according to an aspect of the present disclosure is an encoding apparatus that performs inter prediction in encoding of a target block that configures a moving image, and includes a circuit and a memory, and the circuit When performing the first process of correcting the prediction image of the encoding target block using the luminance around the encoding target block and the luminance around the reference block using the memory, The inter prediction of the encoding target block is performed without performing one or more processes including the second process of correcting the predicted image using the obtained spatial gradient of luminance.

Thus, when performing the first process that is assumed to have a long processing time, the encoding apparatus does not perform one or more processes including the second process that is assumed to have a long processing time, as in the first process. In addition, inter prediction can be performed. Therefore, the encoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding the moving image.

Also, for example, the one or more processes correct the predicted image using a reference image pointed to by the encoding target block using a motion vector of an encoded block around the encoding target block. Includes a third process.

Thereby, when performing the first process, the encoding apparatus can perform the inter prediction without performing the second process and the third process. Therefore, the encoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding the moving image.

Also, for example, the one or more processes are all processes different from the first process among a plurality of processes for correcting the predicted image.

Thereby, when performing the first process, the encoding apparatus can perform the inter prediction without performing the correction process other than the first process. Therefore, the encoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding the moving image.

Also, for example, the circuit ends the inter prediction of the encoding target block without correcting the prediction image after the first processing is performed.

Thereby, when performing the first process, the encoding apparatus can perform the inter prediction without performing the correction process after the first process. Therefore, the encoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding the moving image.

Further, for example, when the circuit determines whether or not the encoding target block is to be encoded in the low delay mode, and the encoding target block is determined to be encoded in the low delay mode. When the first process is performed, inter prediction of the encoding target block is performed without performing the one or more processes.

Thereby, in the low delay mode, the encoding device can shorten the processing time of the stage including the first processing, and can suppress the processing delay in the encoding of the moving image.

In addition, for example, the circuit includes information indicating whether or not the encoding target block is encoded in the low delay mode, and includes information indicating a sequence header area, a picture header area, and a tile header area in the encoded stream of the moving image. , Encoding into at least one of a slice header area and an auxiliary information area.

Thereby, the encoding device can provide the decoding device with information on whether or not it is in the low delay mode.

Also, for example, the circuit determines whether to encode the encoding target block in the low delay mode according to the size of the encoding target picture including the encoding target block.

Thereby, the encoding apparatus can control whether to perform encoding in the low delay mode adaptively according to the size of the picture.

Also, for example, the circuit determines whether or not to encode the block to be encoded in the low delay mode according to the processing capability of the decoding device.

Thereby, the encoding apparatus can control whether to perform encoding in the low delay mode adaptively according to the processing capability of the decoding apparatus.

Also, for example, the circuit determines whether or not to encode the encoding target block in the low delay mode according to profile or level information assigned to the encoded stream of the moving image.

Thereby, the encoding apparatus can control whether to perform encoding in the low delay mode adaptively according to the profile or level.

In addition, for example, a decoding device according to an aspect of the present disclosure is a decoding device that performs inter prediction in decoding a decoding target block constituting a moving image, and includes a circuit and a memory, and the circuit includes the memory Is used to perform the first process of correcting the prediction image of the decoding target block using the luminance around the decoding target block and the luminance around the reference block, the spatial intensity of the luminance obtained from the reference block The inter-prediction of the decoding target block is performed without performing one or more processes including a second process of correcting the predicted image using a simple gradient.

Thereby, when performing the first process that is assumed to have a long processing time, the decoding device does not perform one or more processes including the second process that is assumed to have a long processing time as in the first process. Inter prediction can be performed. Therefore, the decoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

Further, for example, the one or more processes include a third process for correcting the predicted image using a reference image pointed to by the decoding target block using a motion vector of a decoded block around the decoding target block. including.

Thereby, when performing the first process, the decoding apparatus can perform the inter prediction without performing the second process and the third process. Therefore, the decoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

Also, for example, the one or more processes are all processes different from the first process among a plurality of processes for correcting the predicted image.

Thereby, when performing the first process, the decoding apparatus can perform the inter prediction without performing the correction process other than the first process. Therefore, the decoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

Also, for example, the circuit ends the inter prediction of the decoding target block without correcting the prediction image after the first processing is performed.

Thereby, when performing the first process, the decoding apparatus can perform inter prediction without performing the correction process after the first process. Therefore, the decoding apparatus can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

In addition, for example, the circuit determines whether or not to perform decoding of the decoding target block in the low delay mode, and when it is determined that decoding of the decoding target block is performed in the low delay mode, When processing is performed, inter prediction of the decoding target block is performed without performing the one or more processing.

Thereby, in the low delay mode, the decoding apparatus can shorten the processing time of the stage including the first processing, and can suppress the processing delay in the decoding of the moving image.

For example, the circuit may include information indicating whether or not the decoding target block is to be decoded in the low-delay mode, a sequence header area, a picture header area, a tile header area, a slice in the encoded stream of the moving image Decoding is performed from at least one of the header area and the auxiliary information area.

Thereby, the decoding apparatus can obtain information on whether or not it is in the low delay mode from the encoding apparatus.

Also, for example, the circuit determines whether or not to decode the decoding target block in the low delay mode according to the profile or level information assigned to the encoded stream of the moving image.

Thereby, the decoding apparatus can control whether to perform decoding in the low-delay mode adaptively according to the profile or level.

In addition, for example, an encoding method according to an aspect of the present disclosure is an encoding method that performs inter prediction in encoding of an encoding target block configuring a moving image, and includes luminance around the encoding target block and When performing the first process of correcting the prediction image of the encoding target block using the luminance around the reference block, the first correction of the prediction image using the spatial gradient of the luminance obtained from the reference block is performed. Inter prediction of the encoding target block is performed without performing one or more processes including two processes.

Accordingly, when performing the first process that is assumed to have a long processing time, the inter prediction is performed without performing one or more processes including the second process that is assumed to have a long processing time as in the first process. It becomes possible to do. Therefore, it is possible to shorten the processing time of the stage including the first processing, and it is possible to suppress a processing delay in encoding a moving image.

In addition, for example, a decoding method according to an aspect of the present disclosure is a decoding method that performs inter prediction in decoding of a decoding target block constituting a moving image, and includes a luminance around the decoding target block and a surrounding of a reference block In the case where the first process of correcting the prediction image of the decoding target block using luminance is performed, one process includes a second process of correcting the prediction image using a spatial gradient of luminance obtained from the reference block. The inter prediction of the decoding target block is performed without performing the above processing.

Accordingly, when performing the first process that is assumed to have a long processing time, the inter prediction is performed without performing one or more processes including the second process that is assumed to have a long processing time as in the first process. It becomes possible to do. Therefore, it is possible to shorten the processing time of the stage including the first process, and it is possible to suppress a processing delay in decoding the moving image.

In addition, for example, an encoding device according to an aspect of the present disclosure includes a dividing unit, an intra prediction unit, an inter prediction unit, a conversion unit, a quantization unit, an entropy encoding unit, and a loop filter unit. Prepare. The dividing unit divides a moving image into a plurality of blocks. The intra prediction unit performs intra prediction on blocks included in the plurality of blocks. The inter prediction unit performs inter prediction on the block. The conversion unit converts a prediction error between a prediction image obtained by the intra prediction or the inter prediction and an original image to generate a conversion coefficient. The quantization unit quantizes the transform coefficient to generate a quantization coefficient. The entropy encoding unit generates an encoded bitstream by encoding the quantization coefficient. The loop filter unit applies a filter to a reconstructed image generated using the predicted image.

Also, for example, the encoding device performs inter prediction in encoding of the encoding target block constituting the moving image. The inter prediction unit is obtained from the reference block when performing the first process of correcting the prediction image of the coding target block using the luminance around the coding target block and the luminance around the reference block. The inter prediction of the encoding target block is performed without performing one or more processes including a second process for correcting the predicted image using a spatial gradient of luminance.

Also, for example, a decoding device according to an aspect of the present disclosure includes an entropy decoding unit, an inverse quantization unit, an inverse transform unit, an intra prediction unit, an inter prediction unit, and a loop filter unit. The entropy decoding unit decodes quantization coefficients of blocks constituting a moving image from the encoded bit stream. The inverse quantization unit inversely quantizes the quantization coefficient to obtain a transform coefficient. The inverse transform unit inversely transforms the transform coefficient to obtain a prediction error. The intra prediction unit performs intra prediction on the block. The inter prediction unit performs inter prediction on the block. The loop filter unit applies a filter to a reconstructed image generated using a prediction image obtained by the intra prediction or the inter prediction and the prediction error.

Also, for example, the decoding device performs inter prediction in decoding of a decoding target block constituting a moving image. The inter prediction unit, when performing the first process of correcting the prediction image of the decoding target block using the luminance around the decoding target block and the luminance around the reference block, the luminance obtained from the reference block The inter prediction of the decoding target block is performed without performing one or more processes including a second process of correcting the predicted image using a spatial gradient.

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

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

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

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

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

(1) The encoding apparatus or decoding apparatus according to the first embodiment corresponds to the constituent elements described in each aspect of the present disclosure among a plurality of constituent elements constituting the encoding apparatus or decoding apparatus. Replacing the constituent elements with constituent elements described in each aspect of the present disclosure (2) A plurality of constituent elements constituting the encoding apparatus or decoding apparatus with respect to the encoding apparatus or decoding apparatus of the first embodiment The constituent elements corresponding to the constituent elements described in each aspect of the present disclosure are added to the present disclosure after arbitrary changes such as addition, replacement, and deletion of functions or processes to be performed on some constituent elements among the constituent elements. (3) Addition of processes and / or a plurality of processes included in the method to the method performed by the encoding apparatus or decoding apparatus of the first embodiment home Replace 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 after performing arbitrary changes such as replacement and deletion of a part of the processing (4) Implementation The constituent elements described in each aspect of the present disclosure, the constituent elements described in the respective aspects of the present disclosure are part of the plurality of constituent elements constituting the encoding device or the decoding device of the first embodiment (5) Encoding device according to Embodiment 1 that is implemented in combination with a component that includes a part of the functions provided, or a component that performs a part of processing performed by a component described in each aspect of the present disclosure Alternatively, a component provided with a part of the functions provided by some of the components included in the decoding device, or a plurality of components included in the encoding device or the decoding device according to the first embodiment. Some of A component that performs a part of processing performed by a component is a component that is described in each aspect of the present disclosure, a component that includes a part of a function included in a component described in each aspect of the present disclosure, or a book (6) A method performed by the encoding device or the decoding device according to Embodiment 1 is performed in combination with a component that performs a part of processing performed by the component described in each aspect of the disclosure. Of the plurality of processes included in the method, the process corresponding to the process described in each aspect of the present disclosure is replaced with the process described in each aspect of the present disclosure. (7) The encoding apparatus according to the first embodiment or A part of the plurality of processes included in the method performed by the decoding device is performed in combination with the processes described in each aspect of the present disclosure

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

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

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

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

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

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

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

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

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

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

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

The lower right 64x64 block 23 is not divided.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[First specific example of inter prediction processing]
FIG. 11 is a schematic diagram showing a pipeline structure in this example. The example of the pipeline structure in this specific example is an example of a pipeline structure for decoding a moving image, and may be used by the decoding device 200.

Further, the pipeline structure in this specific example includes three stages of a first stage, a second stage, and a third stage. The first stage includes entropy decoding (S101). The second stage includes MV determination (S102), LIC (S103), MC / BIO (S104), OBMC (S105), intra prediction (S106), switching (S107), inverse quantization inverse transformation (S108), and Addition (S109) is included. The third stage includes a loop filter (S110).

In entropy decoding (S101), for example, the entropy decoding unit 202 of the decoding device 200 acquires information used for decoding a moving picture by performing entropy decoding such as variable length decoding on the input stream. Specifically, the entropy decoding unit 202 acquires a quantization coefficient and the like by entropy decoding.

MV determination (S102), LIC (S103), MC / BIO (S104), and OBMC (S105) constitute inter prediction. In inter prediction, the inter prediction unit 218 of the decoding apparatus 200 refers to a reconstructed image in a reference picture different from the processing target picture, and predicts the processing target coding unit (processing target CU) in the processing target picture. Is generated.

In MV determination (S102), the inter prediction unit 218 derives a prediction motion vector (MVP) of the processing target coding unit. For example, the inter prediction unit 218 derives a plurality of prediction motion vectors of the processing target coding unit as a plurality of motion vector candidates of the processing target coding unit, respectively. Then, the inter prediction unit 218 determines a motion vector of the processing target coding unit from the plurality of candidates.

In the LIC (S103), the inter prediction unit 218 generates or corrects a predicted image of the processing target coding unit by LIC (local illumination compensation) processing.

For example, the inter prediction unit 218 derives a luminance correction parameter using a pixel value in a region different from the processing target encoding unit. Specifically, the inter prediction unit 218 derives a luminance correction parameter using the luminance around the processing target coding unit and the luminance around the reference block specified by the motion vector of the processing target coding unit. To do. Then, the inter prediction unit 218 generates or corrects the predicted image of the processing target encoding unit using the luminance correction parameter.

More specifically, as shown in FIG. 9D, the reference block in the reference picture is specified by the motion vector of the processing target encoding unit (the encoding target block or the decoding target block). Then, the luminance correction parameter is calculated according to the change in luminance between the image region adjacent to the processing target encoding unit and the image region adjacent to the reference block.

Then, a predicted image is generated by performing luminance correction processing on the reference image in the reference block using the luminance correction parameter. Alternatively, the predicted image is corrected by performing luminance correction processing on the predicted image derived from the reference image in the reference block using the luminance correction parameter.

In MC / BIO (S104), the inter prediction unit 218 performs generation or correction of a prediction image of the processing target encoding unit by a BIO (bi-directional optical flow) process. For example, the inter prediction unit 218 generates a predicted image of the processing target coding unit by motion compensation (MC) processing, and corrects the predicted image of the processing target coding unit by BIO processing.

Specifically, the inter prediction unit 218 identifies a reference block based on the motion vector of the processing target coding unit, and corrects the predicted image using a spatial gradient of luminance obtained from the reference block. The spatial gradient of luminance obtained from the reference block may be a spatial gradient of luminance in an image obtained from the reference block. The image obtained from the reference block may be a reference image or a predicted image. The predicted image may be a motion compensated image with decimal pixel accuracy.

For example, as illustrated in FIG. 8, the inter prediction unit 218 identifies two reference blocks based on two prediction motion vectors of the processing target coding unit, and acquires two prediction images from the two reference blocks. Then, the inter prediction unit 218 acquires two gradient images by acquiring a spatial gradient of luminance for each of the two predicted images.

Then, the inter prediction unit 218 has a plurality of pixel values based on a plurality of pixel values at a plurality of pixel positions of two prediction images, a plurality of gradient values at a plurality of pixel positions of two gradient images, an optical flow equation, and the like. A plurality of new predicted pixel values at the pixel position are derived. Thereby, the inter prediction unit 218 generates a prediction image to which the BIO process is applied. That is, the inter prediction unit 218 corrects the predicted image by BIO processing.

In the OBMC (S105), the inter prediction unit 218 generates or corrects a predicted image of the processing target coding unit through an OBMC (overlapped block motion compensation) process. For example, using the reference image specified by the motion vector of the processing target coding unit and the reference image specified by the motion vector of the adjacent coding unit adjacent to the processing target coding unit, A predicted image is generated or corrected.

Specifically, as shown in FIGS. 5B and 5C, the inter prediction unit 218 specifies a reference block indicated by the motion vector of the processing target coding unit. In addition, the inter prediction unit 218 identifies one or more reference blocks indicated by one or more motion vectors of one or more coding units adjacent to the processing target coding unit.

Then, the inter prediction unit 218 generates a new prediction image by superimposing a plurality of prediction images obtained from a plurality of reference images in the plurality of reference blocks. In other words, the inter prediction unit 218 corrects the predicted image obtained from the motion vector of the processing target coding unit using the reference image obtained from the motion vector of the processed peripheral coding unit. Here, the processed peripheral encoding unit is a processed encoding unit and is an encoding unit in the vicinity of the processing target encoding unit.

In intra prediction (S106), the intra prediction unit 216 of the decoding device 200 generates a prediction image of the processing target coding unit with reference to the reconstructed image in the processing target picture.

In the switching (S107), a prediction image obtained by inter prediction such as MV determination (S102), LIC (S103), MC / BIO (S104), and OBMC (S105) and prediction obtained by intra prediction (S106). Switch between images.

In the inverse quantization inverse transformation (S108), the inverse quantization unit 204 and the inverse transformation unit 206 of the decoding device 200 perform an inverse quantization inverse transformation process using information obtained by entropy decoding. Specifically, the inverse quantization unit 204 and the inverse transform unit 206 perform inverse quantization inverse transform processing on the quantization coefficient. As a result, the inverse quantization unit 204 and the inverse transform unit 206 restore a difference image that is a prediction error between the original image and the predicted image.

In addition (S109), the addition unit 208 of the decoding device 200 reconstructs the original image by adding the difference image and the predicted image. That is, the adding unit 208 generates a reconstructed image.

In the loop filter (S110), the loop filter unit 212 of the decoding device 200 applies a loop filter process to the reconstructed image. Thereby, for example, the loop filter unit 212 suppresses distortion between coding units. Then, the loop filter unit 212 generates a reconstructed image to which the filter is applied as a decoded image.

The reconstructed image generated in the second stage is reconstructed around the coding unit where the LIC (S103) and intra prediction (S106) are performed in the LIC (S103) and intra prediction (S106) of the subsequent coding unit. There is a possibility of being referred to as a constituent image. Therefore, the reconstructed image generated in the second stage is fed back as an input of LIC (S103) and intra prediction (S106).

In the pipeline structure in this specific example, since the feedback is included in the second stage without straddling a plurality of stages, in the LIC (S103) and intra prediction (S106), the immediately preceding coding unit in the processing order It is possible to refer to the reconstructed image. On the other hand, in the pipeline structure in this specific example, the second stage includes many processes. Therefore, the processing time of the second stage is long.

Note that the processing time corresponds to the processing amount or the number of processing cycles. In addition, the pipeline structure in this specific example is an example of a pipeline structure. Processing may be partially removed, processing may be partially added, and the stage division method is changed. May be. For example, after MV determination, motion compensation (MC) may be performed to generate a predicted image. Thereafter, the predicted image may be corrected by adaptively performing LIC processing, BIO processing, and OBMC processing.

FIG. 12 is a schematic diagram showing an example of block division used for explanation of pipeline processing. In the block division example shown in FIG. 12, two coding tree units are shown. One coding tree unit includes two coding units CU0 and CU1, and the other coding tree unit includes three coding units CU2, CU3, and CU4.

The encoding units CU0, CU1 and CU4 have the same size. The encoding units CU2 and CU3 are the same size. Each size of the encoding units CU0, CU1 and CU4 is twice the size of each of the encoding units CU2 and CU3.

Note that the coding tree unit is a block including one or more coding units and is a square block having a predetermined size. For example, a plurality of coding tree units included in a plurality of pictures constituting a moving image have a predetermined common size. The encoding unit is a rectangular block included in the encoding tree unit and has a variable size. For example, the size of the coding unit included in the coding tree unit may be determined for each coding tree unit.

FIG. 13 is a time chart showing an example of processing timing in the pipeline structure of this specific example described in FIG. FIG. 13 shows processing timings of the five encoding units CU0 to CU4 shown in FIG. Further, S1 to S3 in FIG. 13 indicate processing times of the first stage to the third stage in FIG.

Since the size of each of the encoding units CU0, CU1, and CU4 is twice the size of each of the encoding units CU2 and CU3, the processing time of each stage is also doubled for the encoding units CU0, CU1, and CU4. is there. Further, since the second stage includes many processes, the processing time of the second stage is twice that of the other stages. Further, in each stage, after the processing of the same stage for the immediately preceding coding unit is completed in the processing order, the processing of the same stage for the next coding unit is started.

For example, the process of the second stage for the encoding unit CU1 is started from the time t6 when the process of the second stage for the encoding unit CU0 is completed. Since the processing time of the second stage with respect to the encoding unit CU0 is twice that of the first stage, the processing of the second stage is performed with respect to the encoding unit CU1 from the time t4 when the processing of the first stage is completed. There is a waiting time until the start time t6.

For the encoding unit CU1 and later, a waiting time always occurs at the start of the second stage processing. Then, the waiting time is accumulated for each of the encoding units CU0, CU2, CU3, and CU4. A long waiting time is generated for the encoding unit CU4 from time t8 when the first stage processing is completed to time t14 when the second stage processing is started.

As a result, in the processing of one picture, the processing time including the waiting time increases to about twice the original processing time excluding the waiting time, and all codes in one picture are within the time allotted to one picture. It may be difficult to complete the processing of the digitizing unit.

FIG. 14 is a flowchart showing the inter prediction operation in the pipeline structure of this example described in FIG. For example, the inter prediction unit 218 of the decoding device 200 performs the operation shown in FIG. Further, the inter prediction unit 126 of the encoding device 100 may perform the operation illustrated in FIG. 14, similarly to the inter prediction unit 218 of the decoding device 200.

The inter prediction mode can be selected from a plurality of modes including a normal inter mode and a merge mode. The inter prediction unit 218 selects an inter prediction mode from among a plurality of modes, and determines a motion vector (MV) using the selected mode.

In the case of the normal inter mode (normal inter mode in S201), the inter prediction unit 218 refers to a plurality of motion vectors of a plurality of processed coding units around the processing target coding unit, and a plurality of motion vector predictors (MVP). ) To get. Thus, the inter prediction unit 218 creates a normal MVP list including a plurality of motion vector predictors. Then, the inter prediction unit 218 selects one prediction motion vector from the created normal MVP list.

Then, the inter prediction unit 218 determines the motion vector of the processing target unit by adding the difference motion vector (MVD) to the selected prediction motion vector (S202).

In the encoding apparatus 100, the inter prediction unit 126 determines a motion vector by motion detection or the like, and derives a difference motion vector between the motion vector and the predicted motion vector. Then, the entropy encoding unit 110 encodes the difference motion vector. And in the decoding apparatus 200, the entropy decoding part 202 decodes a difference motion vector, and a difference motion vector is derived | led-out.

Further, in the merge mode (merge mode in S201), the inter prediction unit 218 refers to the plurality of motion vectors of the plurality of processed encoding units around the processing target encoding unit, and generates a plurality of predicted motion vectors (MVP). ) To get. Thus, the inter prediction unit 218 creates a merge MVP list including a plurality of motion vector predictors. Then, the inter prediction unit 218 selects one predicted motion vector from the created merge MVP list.

Then, the inter prediction unit 218 determines the selected prediction motion vector as it is as the motion vector of the processing target encoding unit (S203).

Next, the inter prediction unit 218 determines whether or not to apply the LIC process when performing motion compensation using the motion vector determined in the normal inter mode or the merge mode (S204).

Here, when it is determined that the LIC process is to be applied (Yes in S204), the inter prediction unit 218 performs the motion compensation with the LIC process in which the reconstructed image around the processing target encoding unit is referred to the target encoding. This is performed according to the motion vector of the unit (S206). Thereby, the inter prediction unit 218 generates a predicted image.

On the other hand, when it is determined that the LIC process is not applied (No in S204), the inter prediction unit 218 performs normal motion compensation without the LIC process according to the motion vector of the processing target coding unit (S205). Thereby, the inter prediction unit 218 generates a predicted image.

For example, when LIC processing is applied, the inter prediction unit 218 uses a reconstructed image of a coding unit adjacent to the processing target coding unit. Therefore, the feedback processing shown in FIG. 11 is used. Note that the determination as to whether or not to apply the LIC process may be performed according to conditions such as a prediction mode, a prediction direction, or a size of the processing target coding unit. Further, a signal indicating whether or not to apply LIC processing may be explicitly described in the stream. And determination may be performed according to the signal.

Next, the inter prediction unit 218 determines whether or not to apply the BIO process to the processing target coding unit (S207). Here, when it is determined that the BIO process is applied (Yes in S207), the inter prediction unit 218 performs correction using the BIO process on the generated predicted image (S208). On the other hand, when it is determined that the BIO process is not applied (No in S207), the inter prediction unit 218 does not perform correction based on the BIO process on the generated predicted image.

The determination as to whether or not to apply the BIO process may be performed according to conditions such as a prediction mode, a prediction direction, or a size of the processing target coding unit. Further, a signal indicating whether or not to apply BIO processing may be explicitly described in the stream. And determination may be performed according to the signal.

Next, the inter prediction unit 218 determines whether or not to apply the OBMC process to the processing target coding unit (S209). Here, when it is determined that the OBMC process is applied (Yes in S209), the inter prediction unit 218 performs a correction process using the OBMC process on the generated predicted image, thereby obtaining a final predicted image. Generate (S210). On the other hand, when it is determined that the OBMC process is not applied (No in S209), the inter prediction unit 218 treats the predicted image generated without using the OBMC process as a final predicted image as it is.

The determination of whether to apply the OBMC process may be performed according to conditions such as the prediction mode, the prediction direction, or the size of the processing target coding unit. Further, a signal indicating whether or not to apply OBMC processing may be explicitly described in the stream. And determination may be performed according to the signal.

The above processing (S201 to S210) is repeated for each encoding unit. Note that inter prediction is not limited to each coding unit, and may be performed for each prediction unit or may be performed for each other block.

As described above, when the LIC process is applied to the processing target encoding unit, more processes are performed than when the LIC process is not applied. As a result, the processing time becomes long, and there is a possibility that the waiting time for starting the processing of the second stage in the pipeline control increases as described with reference to FIG.

Note that the above processing flow is an example, and a part of the above processing may be omitted, or processing not shown above may be added. For example, the inter prediction unit 218 generates a prediction image by performing normal motion compensation, and then performs adaptive LIC processing, or adaptively performs BIO processing and OBMC processing to generate the prediction image. It may be corrected.

Further, the encoding device 100 and the decoding device 200 have a difference in whether a signal used for processing is encoded into a stream or decoded from the stream. However, the processing flow described here is similar to the encoding device 100 and the decoding device. This is basically the same as 200. For example, the same processing as that performed by the inter prediction unit 218 in the decoding device 200 may be performed by the inter prediction unit 126 in the encoding device 100.

In addition, here, processing is performed for each encoding unit, but processing may be performed for each arbitrarily determined block. Therefore, the encoding unit here may be replaced with a block.

[Second specific example of inter prediction processing]
In this specific example, an increase in the amount of inter prediction processing when the LIC processing is performed is suppressed.

FIG. 15 is a schematic diagram showing a pipeline structure in this example. The pipeline structure example in this specific example is a pipeline structure example for decoding a moving image, similarly to the pipeline structure example in the first specific example, and may be used by the decoding device 200.

Also, the pipeline structure in this specific example includes three stages, a first stage, a second stage, and a third stage, as in the pipeline structure example in the first specific example. The first stage includes entropy decoding (S101). The second stage includes MV determination (S102), LIC (S103), MC (S111), MC / BIO (S104), OBMC (S105), intra prediction (S106), switching (S107), inverse quantization inverse transformation ( S108) and addition (S109). The third stage includes a loop filter (S110).

In MC (S111), the inter prediction unit 218 of the decoding device 200 generates a prediction image of the processing target coding unit by motion compensation (MC) processing. Entropy decoding (S101), MV determination (S102), LIC (S103), MC / BIO (S104), OBMC (S105), intra prediction (S106), switching (S107), inverse quantization inverse transformation (S108), addition The specific processes of (S109) and the loop filter (S110) are the same as those of the first specific example.

However, unlike the first specific example, when LIC (S103) is performed in inter prediction, BIO / MC (S104) and OBMC (S105), which are processes related to generation of a predicted image, are not performed and MC ( Only S111) is performed to generate a predicted image. In the inter prediction, when LIC (S103) is not performed, MC / BIO (S104) and OBMC (S105) are adaptively performed as in the first specific example, and a predicted image is generated.

The reconstructed image generated in the second stage is reconstructed around the coding unit where the intra prediction (S106) and LIC (S106) are performed in the LIC (S103) and intra prediction (S106) of the subsequent coding unit. There is a possibility of being referred to as a constituent image. Therefore, the reconstructed image generated in the second stage is fed back as an input of LIC (S103) and intra prediction (S106).

Compared to the first specific example, in this specific example, the number of continuous processes related to the inter prediction in the second stage is small. Therefore, even if feedback processing is performed as in the first specific example, the processing time of the entire second stage is significantly reduced.

The pipeline structure in this specific example is an example of the pipeline structure, and the processing may be partially removed, the processing may be partially added, or the stage dividing method is changed. May be. For example, after MV determination, motion compensation (MC) may be performed to generate a predicted image. Thereafter, the predicted image may be corrected by adaptively performing LIC processing, BIO processing, and OBMC processing.

FIG. 16 is a time chart showing an example of processing timing in the pipeline structure of the specific example described in FIG. FIG. 16 shows processing timings of the five encoding units CU0 to CU4 shown in FIG. Similar to the first specific example, the size of each of the encoding units CU0, CU1, and CU4 is twice the size of each of the encoding units CU2 and CU3. Therefore, for each of the encoding units CU0, CU1, and CU4, The stage processing time is also doubled.

On the other hand, the processing time of the second stage in this specific example is shorter than that of the first specific example, and the length of the processing time of the second stage in this specific example is the same as the processing time of the other stages. . Then, in each stage, after the processing of the same stage for the immediately preceding coding unit is completed in the processing order, the processing of the same stage for the next coding unit is started.

For example, the processing of the second stage for the encoding unit CU1 is started from time t4 when the processing of the second stage for the encoding unit CU0 is completed. Since the processing time of the second stage for the encoding unit CU0 is the same as the other stages, the processing of the second stage is started without waiting time after the processing of the first stage is completed for the encoding unit CU1. Is possible.

On the other hand, since the size of the encoding unit CU2 is smaller than the size of the immediately preceding encoding unit CU1 in the processing order, a waiting time is generated between the first stage and the second stage with respect to the encoding unit CU2. . However, this waiting time is not accumulated, and there is no waiting time in the processing of the encoding unit CU4.

As a result, in the processing of one picture, the processing time including the waiting time becomes substantially equal to the original processing time excluding the waiting time. Therefore, there is a high possibility that processing of one picture is completed within the time allotted to one picture.

FIG. 17 is a flowchart showing the inter prediction operation in the pipeline structure of this example described in FIG. For example, the inter prediction unit 218 of the decoding device 200 performs the operation shown in FIG. Further, the inter prediction unit 126 of the encoding device 100 may perform the operation illustrated in FIG. 17, similarly to the inter prediction unit 218 of the decoding device 200. Basically, the plurality of processes (S201 to S210) of this specific example shown in FIG. 17 are the same as the plurality of processes (S201 to S210) of the first specific example shown in FIG.

Compared with the first specific example, in this specific example, when it is determined that the LIC process is applied to motion compensation (Yes in S204), the inter prediction unit 218 performs a BIO process (a process related to generation of a predicted image) ( S208) and OBMC processing (S210) are not performed. Then, the inter prediction unit 218 performs only motion compensation (S206) with LIC processing, and generates a final predicted image.

Thereby, an increase in the amount of inter prediction processing when the LIC processing is applied to the processing target encoding unit is suppressed. Then, it is assumed that the processing time for inter prediction when the LIC process is applied is shorter than that when the BIO process and the OBMC process are applied. As a result, as described with reference to FIG. 16, there is a high possibility that the waiting time for starting the processing of the second stage in the pipeline control is suppressed.

In the example of FIG. 17, when the LIC process is applied to the processing target encoding unit, both the BIO process and the OBMC process are not performed, and a predicted image is generated. However, in this case, the predicted image may be generated without performing only the BIO process, or the predicted image may be generated without performing only the OBMC process. Thereby, although the reduction effect of processing amount and processing time decreases, it becomes possible to generate a predicted image with higher accuracy. Therefore, there is a high possibility that the encoding efficiency is improved.

In particular, the BIO processing uses a complicated arithmetic expression based on an optical flow equation or the like. Therefore, it is assumed that the processing time of BIO processing is long. Therefore, when the LIC process is applied, it is possible to prevent the processing time of the second stage from becoming too long by controlling the BIO process not to be performed.

In addition, after determining whether or not to apply the LIC process, when another process related to the predicted image generation continues in addition to the BIO process and the OBMC process, the determination result of whether or not the other process also applies the LIC process May be skipped. For example, the process related to the predicted image generation is a process of correcting the predicted image so that the predicted image approaches the original image.

Also, the above processing flow is an example, and a part of the above processing may be removed, or processing not shown above may be added. For example, the inter prediction unit 218 generates a prediction image by performing normal motion compensation, and then performs adaptive LIC processing, or adaptively performs BIO processing and OBMC processing to generate the prediction image. It may be corrected.

Further, the encoding device 100 and the decoding device 200 have a difference in whether a signal used for processing is encoded into a stream or decoded from the stream. However, the processing flow described here is similar to the encoding device 100 and the decoding device. This is basically the same as 200. For example, the same processing as that performed by the inter prediction unit 218 in the decoding device 200 may be performed by the inter prediction unit 126 in the encoding device 100.

15, 16, and 17, the specific example described with reference to FIGS. 15, 16, and 17 suppresses an increase in processing amount when the LIC processing is applied to the processing target encoding unit, and includes the LIC processing in pipeline control. It is possible to shorten the processing time. And it is possible to reduce the waiting time for starting stage processing including LIC processing in pipeline control. Therefore, even when the processing performance of the decoding apparatus 200 is low, there is a high possibility that the processing of one picture is completed within the time allotted to one picture.

Note that, here, processing is performed for each encoding unit, but processing may be performed for each arbitrarily defined block. Therefore, the encoding unit here may be replaced with a block.

[Third specific example of inter prediction processing]
In this specific example, an increase in the amount of inter prediction processing when the LIC processing is performed in the low delay mode is suppressed. In this specific example, the pipeline structure in the first specific example and the pipeline structure in the second specific example are switched depending on whether or not the low delay mode is used.

FIG. 18 is a flowchart showing the operation of inter prediction in this example. For example, the inter prediction unit 218 of the decoding device 200 performs the operation shown in FIG. Also, the inter prediction unit 126 of the encoding device 100 may perform the operation illustrated in FIG. 18, similarly to the inter prediction unit 218 of the decoding device 200. Basically, the plurality of processes (S201 to S210) of this specific example shown in FIG. 18 are the same as the plurality of processes (S201 to S210) of the second specific example shown in FIG.

Compared to the second specific example, in this specific example, the inter prediction unit 218 sets the processing target coding unit in the low delay mode when the LIC processing (S206) is applied to the processing target coding unit. It is determined whether or not to process (S211).

If it is determined that the processing target coding unit is to be processed in the low delay mode (Yes in S211), the inter prediction unit 218 performs BIO processing (S208) and OBMC processing (S210), which are processing related to generation of a predicted image. Do not do. In this case, the inter prediction unit 218 treats a predicted image generated by performing only motion compensation with LIC processing as a final predicted image.

Further, when it is determined that the processing target encoding unit is not to be processed in the low delay mode (No in S211), the inter prediction unit 218 determines whether to perform the BIO process and whether to perform the OBMC process. (S207, S209). Then, the inter prediction unit 218 generates a final predicted image by adaptively performing the BIO process (S208) and the OBMC process (S210) according to the determination result.

Thereby, in the low delay mode, an increase in the processing amount of inter prediction when the LIC processing is applied to the processing target coding unit is suppressed. Therefore, as described with reference to FIG. 16, there is a high possibility that the waiting time for starting the processing of the second stage in the pipeline control is suppressed.

On the other hand, in a mode other than the low delay mode, the processing amount when the LIC processing is applied to the processing target coding unit increases. Therefore, as described with reference to FIG. 13, a waiting time for starting the processing of the second stage is generated in the pipeline control. However, it is possible to generate a predicted image with higher accuracy. Therefore, there is a high possibility that the encoding efficiency is improved.

The entropy encoding unit 110 of the encoding apparatus 100 may generate information indicating whether or not to process the encoding unit in the low delay mode and encode it into a stream. And the entropy decoding part 202 of the decoding apparatus 200 may decode and acquire the information which shows whether an encoding unit is processed in a low delay mode from a stream. Accordingly, the encoding device 100 and the decoding device 200 can determine whether or not to process the encoding unit in the low delay mode so that the same determination result is obtained.

For example, information indicating whether or not to process the encoding unit in the low delay mode is described in at least one of a sequence header area, a picture header area, a slice header area, and an auxiliary information area in the encoded stream. In this case, the encoding apparatus 100 encodes information indicating whether or not to process the encoding unit in the low delay mode into at least one of them. Also, the decoding apparatus 200 decodes information indicating whether or not to process the encoding unit in the low delay mode from at least one of them.

Here, the sequence header area is an area in which parameters common to moving images are stored. The sequence header area may be, for example, an SPS (sequence parameter set). In addition, the picture header area is an area in which parameters common to pictures constituting a moving image are stored. The picture header area may be, for example, a PPS (Picture Parameter Set). The slice header area is an area in which parameters common to slices constituting a picture are stored.

The auxiliary information area is an area in which parameters different from the parameters stored in the sequence header area, the picture header area, and the slice header area are stored. The auxiliary information area may be, for example, SEI (Supplemental Enhancement Information) or a tile header area. The tile header area is an area in which parameters common to the tiles constituting the picture are stored.

Also, for example, the encoding apparatus 100 may switch whether to process the encoding unit in the processing target picture in the low delay mode according to the size of the processing target picture. Similarly to the encoding device 100, the decoding device 200 may switch whether or not to process the encoding unit in the processing target picture in the low delay mode according to the size of the processing target picture. For example, the size of the picture corresponds to the number of pixels in the picture.

Specifically, for example, when the size of the processing target picture is small, the number of encoding units in the processing target picture is small, and there is room in processing time. Therefore, in this case, the encoding apparatus 100 does not apply the low delay mode. On the other hand, when the size of the processing target picture is large, the number of encoding units in the processing target picture is large, and there is no room for processing time. Therefore, in this case, the encoding apparatus 100 applies the low delay mode.

Here, whether or not the size of the processing target picture is large may be determined according to a predetermined criterion. For example, whether or not the size of the processing target picture is large may be determined based on whether or not the size of the processing target picture is larger than a threshold value.

Also, for example, the encoding apparatus 100 may switch whether to process the encoding unit in the low delay mode according to the processing capability of the decoding apparatus 200 that receives the encoded stream and decodes the moving image. Also, the decoding apparatus 200 may switch whether to process the encoding unit in the low delay mode according to the processing capability of the decoding apparatus 200.

Specifically, for example, when the processing capability of the decoding device 200 is high, it is possible to perform many processes in a certain processing time. Therefore, in this case, the encoding apparatus 100 does not apply the low delay mode. On the other hand, when the processing capability of the decoding device 200 is low, it is difficult to perform many processes in a certain processing time. Therefore, in this case, the encoding apparatus 100 applies the low delay mode.

Here, whether or not the processing capability of the decoding device 200 is high may be determined according to a predetermined criterion. For example, whether or not the processing capability of the decoding device 200 is high may be determined by whether or not a numerical value indicating the processing capability of the decoding device 200 is larger than a threshold value.

For example, the decoding device 200 may acquire the processing capability of the decoding device 200 from each component of the decoding device 200 or the like. Then, the encoding apparatus 100 may acquire the processing capability of the decoding apparatus 200 from the decoding apparatus 200 through information exchange performed in advance. Or when the encoding apparatus 100 and the decoding apparatus 200 are integrated, the encoding apparatus 100 and the decoding apparatus 200 may determine each processing capability, without performing information exchange.

Also, for example, the encoding apparatus 100 may switch whether to process the encoding unit in the low delay mode according to the profile or level information assigned to the encoded stream. Also, the decoding apparatus 200 may switch whether to process the encoding unit in the low delay mode according to the profile or level information assigned to the encoded stream.

The above profile shows the technical requirements defined for the stream of images. Technical requirements correspond to a set of functions. More specifically, the technical requirements correspond to the type of color space, the size of color depth, the availability of entropy slices, and the like. In addition, the above levels indicate numerical parameter requirements defined for an image stream. The parameter requirement corresponds to the processing load, the amount of memory used, and the like. More specifically, the parameter requirements correspond to a maximum bit rate, a maximum sample rate, a maximum picture size, and the like.

Specifically, for example, the encoding device 100 does not apply the low delay mode to a profile and a level that are assumed that the decoding device 200 that decodes a moving image has sufficient processing capability. On the other hand, the encoding device 100 applies the low-delay mode to the profile and the level that are assumed that the decoding device 200 does not have sufficient processing capability. Whether to apply the low delay mode may be determined in advance for each profile or each level.

For example, information indicating whether to apply the low delay mode may be encoded and decoded by encoding and decoding information indicating a profile or a level assigned to the encoded stream. Whether or not the low delay mode is applied is determined adaptively for each predetermined processing unit with respect to a predetermined profile or a predetermined level, and information indicating whether or not the low delay mode is applied is encoded and decoded. May be performed for each predetermined processing unit.

In the above, basically, whether to apply the low delay mode is determined according to the processing capability of the decoding device 200. Instead of the processing capability of the decoding device 200 or in addition to the processing capability of the decoding device 200, whether to apply the low delay mode may be determined according to the processing capability of the encoding device 100. The processing capability of the encoding device 100 can be acquired by the encoding device 100 and the decoding device 200 in the same manner as the processing capability of the decoding device 200.

For example, whether to apply the low delay mode may be determined according to a lower processing capability among the processing capability of the encoding device 100 and the processing capability of the decoding device 200.

Also, the encoding device 100 and the decoding device 200 apply the low delay mode according to a combination of one or more of the picture size, the processing capability of the encoding device 100, the processing capability of the decoding device 200, a profile, and a level. It may be determined whether or not. For example, the encoding apparatus 100 and the decoding apparatus 200 determine that the low delay mode is applied when the combination satisfies a predetermined criterion, and do not apply the low delay mode when the combination does not satisfy the predetermined criterion. May be determined.

In the encoding apparatus 100, the inter prediction unit 126 may determine whether or not to apply the low delay mode, and other components may determine whether or not to apply the low delay mode. . Similarly, in the decoding device 200, the inter prediction unit 218 may determine whether or not to apply the low delay mode, and other components may determine whether or not to apply the low delay mode. Also good.

Also, the information indicating whether or not to process the encoding unit in the low delay mode is not encoded in the encoded stream as a signal of information indicating whether or not to process the encoding unit strictly in the low delay mode. May be. That is, information indicating whether or not to process the encoding unit in the low delay mode may be encoded in the encoded stream as a signal having another meaning.

For example, a signal indicating forcibly prohibiting application of BIO processing to an encoding unit to which LIC processing is applied, and forcing application of OBMC processing to an encoding unit to which LIC processing is applied. Two signals, a signal indicating prohibition, may be encoded. As another example, information indicating whether or not to process the encoding unit in the low delay mode is directly associated with the profile or level, so that the encoding unit in the low delay mode according to only the signal indicating the profile or level. It may be determined whether or not to process.

In FIG. 18, when the LIC process is applied to the processing target unit in the low delay mode, the inter prediction unit 218 generates a predicted image without performing both the BIO process and the OBMC process. However, in this case, the inter prediction unit 218 may generate a predicted image without performing only the BIO process, or may generate a predicted image without performing only the OBMC process. Thereby, although the reduction effect of processing amount and processing time decreases, it becomes possible to generate a predicted image with higher accuracy. Therefore, there is a high possibility that the encoding efficiency is improved.

In addition, after determining whether or not to apply the LIC process, when another process related to prediction image generation other than the BIO process and the OBMC process continues, the inter prediction unit 218 also applies the LIC process to the other process. You may skip according to the determination result etc. of no.

Note that the above processing flow is an example, and a part of the above processing may be omitted, or processing not shown above may be added. For example, the inter prediction unit 218 generates a prediction image by performing normal motion compensation, and then performs adaptive LIC processing, or adaptively performs BIO processing and OBMC processing to generate the prediction image. It may be corrected.

Further, the encoding device 100 and the decoding device 200 have a difference in whether a signal used for processing is encoded into a stream or decoded from the stream. However, the processing flow described here is similar to the encoding device 100 and the decoding device. This is basically the same as 200. For example, the same processing as that performed by the inter prediction unit 218 in the decoding device 200 may be performed by the inter prediction unit 126 in the encoding device 100.

In addition, here, processing is performed for each encoding unit, but processing may be performed for each arbitrarily determined block. Therefore, the encoding unit here may be replaced with a block.

This specific example described with reference to FIG. 18 suppresses an increase in processing amount when the LIC process is applied to the processing target coding unit in the low delay mode, and the pipeline control includes a stage including the LIC process. Processing time can be shortened. On the other hand, the processing amount when the LIC processing is applied to the processing target encoding unit other than the low delay mode is not reduced, but the encoding efficiency can be increased.

This makes it possible to select an optimal processing method according to the processing capability or encoding conditions of the encoding device 100 and the decoding device 200. Therefore, the applicability for a wide range of applications is increased.

[Modified example of inter prediction processing]
In the inter prediction of each of the above specific examples, any of the following processes may be performed.

(Process 1) When the LIC process is performed on the processing target encoding unit whose size is larger than the specific value, the predicted image may be generated without performing a part of the process accompanying the generation of the predicted image. Thereby, it is suppressed that processing time becomes long.

(Process 2) When the LIC process is performed on the processing target encoding unit having a size larger than that of the encoding unit encoded immediately before, the predicted image is generated without performing a part of the process associated with the generation of the predicted image. It may be broken. Thereby, it is suppressed that waiting time becomes long.

(Process 3) When the number of coding units that have been subjected to LIC processing within a certain period is greater than a specific value, when the LIC processing is performed on a processing target coding unit, The predicted image may be generated without performing a part of the process. Thereby, accumulation of waiting time is suppressed.

(Process 4) When the ratio of coding units that have been subjected to LIC processing within a certain period is greater than a specific value, when the LIC processing is performed on a processing target coding unit, the processing associated with generation of a predicted image The predicted image may be generated without performing a part of the process. Thereby, accumulation of waiting time is suppressed.

(Process 5) The predetermined period may be a process period of a fixed number of coding tree units (CTUs) immediately before the process target coding unit. As a result, an increase in processing delay is suppressed according to the result of processing of a certain number of coding tree units.

(Processing 6) The certain period may be the processing period of the entire slice or the picture to which the processing target encoding unit belongs. As a result, an increase in processing delay is suppressed in accordance with the result of processing of the slice or picture.

(Process 7) In the case where the LIC process is performed on the processing target encoding unit, when the number of the plurality of encoding units on which the LIC process is continuously performed until immediately before that is larger than the specific value, the prediction image is generated. The prediction image may be generated without performing a part of the process associated with. Thereby, accumulation of waiting time is suppressed.

(Process 8) The encoding apparatus 100 may perform a simulation process for estimating a waiting time in pipeline control. When the LIC process is performed on the processing target coding unit and the waiting time estimated at the start of the process is larger than the specific value, the prediction is performed without performing a part of the process associated with the generation of the predicted image. Image generation may be performed. Thereby, it is suppressed that waiting time becomes long.

[LIC processing]
Hereinafter, the LIC process will be described more specifically. In the LIC process, a luminance correction parameter is derived using the luminance pixel value of the peripheral reference region of the processing target block and the luminance pixel value of the peripheral reference region of the reference block, and the prediction image is generated or corrected according to the luminance correction parameter. Done (see FIG. 9D).

Specifically, before the LIC process, the inter prediction unit 218 of the decoding device 200 acquires a motion vector for specifying a reference block in the reference picture for the processing target coding unit. Here, the reference picture is a processed picture. Then, the inter prediction unit 218 acquires a reference image that is an image of a reference block indicated by the motion vector. Then, the inter prediction unit 218 acquires the luminance pixel value of the peripheral reference region of the processing target encoding unit and the luminance pixel value of the peripheral reference region of the reference block.

Here, the peripheral reference area of the processing target encoding unit is determined in one or more processed peripheral encoding units determined to be referenceable. The relative position of the reference block in the peripheral reference area is the same as the relative position of the reference block in the peripheral reference area with respect to the reference block and the relative position of the processing target coding unit in the peripheral reference area with respect to the processing target coding unit. Determined.

Specifically, for example, when the peripheral reference region of the processing target coding unit is determined at the left position with respect to the processing target encoding unit, the peripheral reference region of the reference block is determined at the left position with respect to the reference block. It is done. Also, for example, when the peripheral reference region of the processing target coding unit is determined at a position above the processing target encoding unit, the peripheral reference region of the reference block is determined at a position above the reference block.

The peripheral reference area of the processing target encoding unit may be a partial area in one or more processed peripheral encoding units determined to be referenceable. For example, the peripheral reference region of the processing target encoding unit is a region of pixels adjacent to the processing target encoding unit among regions included in one or more processed peripheral encoding units determined to be referenceable. Also good.

Next, the inter prediction unit 218 derives a luminance correction parameter using the luminance pixel value of the peripheral reference region of the processing target encoding unit and the luminance pixel value of the peripheral reference region of the reference block. For example, the inter prediction unit 218 uses these luminance pixel values to indicate how the luminance value has changed between the processing target picture including the processing target encoding unit and the reference picture including the reference block. Information is extracted, and luminance correction parameters are derived according to the information.

The luminance correction parameter is, for example, a parameter for linear conversion of luminance pixel values. Specifically, the luminance correction parameter may be α and β for performing linear conversion of the luminance pixel value by α × luminance pixel value + β. Further, the inter prediction unit 218 obtains a result close to the luminance pixel value of the peripheral reference region of the processing target coding unit when linear conversion is performed on the luminance pixel value of the peripheral reference region of the reference block. Then, a luminance correction parameter is derived.

Then, the inter prediction unit 218 generates a predicted image using the brightness correction parameter. For example, the inter prediction unit 218 performs a luminance correction process on the reference image specified by the motion vector of the processing target encoding unit using the luminance correction parameter, thereby generating the predicted image of the processing target encoding unit from the reference image. Is generated. In other words, the inter prediction unit 218 corrects the predicted image generated from the reference image using the brightness correction parameter.

The inter prediction unit 218 repeats the above processing for each encoding unit. Note that the inter prediction unit 218 may perform the same process as described above for each sub-block obtained by further dividing the coding unit, not for each coding unit.

In the above description, the inter prediction unit 218 of the decoding device 200 performs the LIC process. However, the inter prediction unit 126 of the encoding device 100 also performs the LIC process similarly to the inter prediction unit 218 of the decoding device 200. I do. In the decoding device 200, a component different from the inter prediction unit 218 may perform the LIC process. Similarly, in the encoding device 100, a component different from the inter prediction unit 126 may perform LIC processing.

As described above, the peripheral reference region of the processing target coding unit is configured by, for example, a pixel region adjacent to the left side or the upper side of the processing target coding unit. A luminance correction parameter is derived according to the luminance pixel value of the peripheral reference region of the processing target encoding unit and the luminance pixel value of the peripheral reference region of the reference block. Then, a predicted image is generated or corrected using the brightness correction parameter.

Note that the shape of the peripheral reference region is not limited to the example in FIG. 9D and may be other shapes. For example, the peripheral reference region may include a pixel region that is not directly adjacent to the processing target encoding unit.

In LIC processing, it is assumed that it takes a long time to derive appropriate brightness correction parameters. In the above plurality of examples, when the LIC process is performed, the other part of the process is not performed, so that it is possible to prevent the processing time of the stage including the LIC process from becoming too long.

[Example of implementation]
FIG. 19 is a block diagram illustrating an implementation example of the encoding device 100. The encoding device 100 includes a circuit 160 and a memory 162. For example, a plurality of components of the encoding device 100 illustrated in FIG. 1 are implemented by the circuit 160 and the memory 162 illustrated in FIG.

The circuit 160 is an electronic circuit that can access the memory 162 and performs information processing. For example, the circuit 160 is a dedicated or general-purpose electronic circuit that encodes a moving image using the memory 162. The circuit 160 may be a processor such as a CPU. The circuit 160 may be an aggregate of a plurality of electronic circuits.

Further, for example, the circuit 160 may serve as a plurality of constituent elements excluding the constituent elements for storing information among the plurality of constituent elements of the encoding device 100 shown in FIG. That is, the circuit 160 may perform the operation described above as the operation of these components.

The memory 162 is a dedicated or general-purpose memory in which information for the circuit 160 to encode a moving image is stored. The memory 162 may be an electronic circuit, may be connected to the circuit 160, or may be included in the circuit 160.

Further, the memory 162 may be an assembly of a plurality of electronic circuits or may be configured by a plurality of sub memories. Further, the memory 162 may be a magnetic disk or an optical disk, or may be expressed as a storage or a recording medium. The memory 162 may be a non-volatile memory or a volatile memory.

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

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

Note that in the encoding device 100, not all of the plurality of components shown in FIG. 1 may be mounted, or all of the plurality of processes described above may not be performed. Some of the plurality of components shown in FIG. 1 may be included in another device, and some of the plurality of processes described above may be executed by another device. Then, in the encoding device 100, a part of the plurality of components illustrated in FIG. 1 is mounted, and a part of the plurality of processes described above is performed, so that processing delay can be suppressed.

FIG. 20 is a flowchart showing an operation example of the encoding apparatus 100 shown in FIG. For example, the circuit 160 in the encoding device 100 performs the operation illustrated in FIG. 20 using the memory 162, so that the encoding device 100 performs inter prediction in encoding of the encoding target block constituting the moving image. I do.

Specifically, when performing the first process, the circuit 160 performs inter prediction of the current block without performing one or more processes including the second process (S301). Here, the first process is a process of correcting the prediction image of the encoding target block using the luminance around the encoding target block and the luminance around the reference block. The second process is a process of correcting the predicted image using the spatial gradient of luminance obtained from the reference block.

Thereby, when performing the first process that is assumed to have a long processing time, the encoding apparatus 100 performs one or more processes including the second process that is assumed to have a long processing time, similarly to the first process. Without inter prediction. Therefore, the encoding apparatus 100 can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding a moving image.

For example, the one or more processes described above include a third process of correcting a predicted image using a reference image pointed to by the encoding target block using a motion vector of an encoded block around the encoding target block. May be included. Thereby, when performing the first process, the encoding apparatus 100 can perform the inter prediction without performing the second process and the third process. Therefore, the encoding apparatus 100 can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding a moving image.

Further, for example, the one or more processes described above may be all processes different from the first process among a plurality of processes for correcting the predicted image. Thereby, when performing the first process, the encoding apparatus 100 can perform the inter prediction without performing the correction process other than the first process. Therefore, the encoding apparatus 100 can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding a moving image.

Further, for example, the circuit 160 may end the inter prediction of the encoding target block without correcting the prediction image after the first process is performed. Thereby, when performing the first process, the encoding apparatus 100 can perform the inter prediction without performing the correction process after the first process. Therefore, the encoding apparatus 100 can shorten the processing time of the stage including the first process, and can suppress a processing delay in encoding a moving image.

Also, for example, the circuit 160 may determine whether or not to encode the encoding target block in the low delay mode. When it is determined that the encoding target block is to be encoded in the low delay mode, the circuit 160 performs the first process without performing the above-described one or more processes. A prediction may be made. Thereby, the encoding apparatus 100 can shorten the processing time of the stage including the first processing in the low delay mode, and can suppress the processing delay in encoding the moving image.

Further, for example, the circuit 160 indicates information indicating whether or not the encoding target block is to be encoded in the low-delay mode, as a sequence header area, a picture header area, a tile header area, and a slice header in the moving image encoded stream. It may be encoded into at least one of the area and the auxiliary information area. Thereby, the encoding apparatus 100 can provide the decoding apparatus 200 with information on whether or not the low delay mode is set.

Further, for example, the circuit 160 may determine whether or not to encode the encoding target block in the low delay mode according to the size of the encoding target picture including the encoding target block. Thereby, the encoding apparatus 100 can control whether to perform encoding in the low delay mode adaptively according to the size of the picture.

Further, for example, the circuit 160 may determine whether to encode the block to be encoded in the low delay mode according to the processing capability of the decoding device 200. Thereby, the encoding apparatus 100 can control whether to perform encoding in the low delay mode adaptively according to the processing capability of the decoding apparatus 200.

Also, for example, the circuit 160 may determine whether or not to encode the encoding target block in the low delay mode according to the profile or level information assigned to the encoded stream of the moving image. Accordingly, the encoding apparatus 100 can control whether to perform encoding in the low delay mode adaptively according to the profile or the level.

FIG. 21 is a block diagram illustrating an implementation example of the decoding device 200. The decoding device 200 includes a circuit 260 and a memory 262. For example, a plurality of components of the decoding device 200 illustrated in FIG. 10 are implemented by the circuit 260 and the memory 262 illustrated in FIG.

The circuit 260 is an electronic circuit that can access the memory 262 and performs information processing. For example, the circuit 260 is a dedicated or general-purpose electronic circuit that decodes a moving image using the memory 262. The circuit 260 may be a processor such as a CPU. The circuit 260 may be an aggregate of a plurality of electronic circuits.

Further, for example, the circuit 260 may serve as a plurality of constituent elements excluding the constituent elements for storing information among the plurality of constituent elements of the decoding device 200 shown in FIG. That is, the circuit 260 may perform the operation described above as the operation of these components.

The memory 262 is a dedicated or general-purpose memory in which information for the circuit 260 to decode a moving image is stored. The memory 262 may be an electronic circuit, may be connected to the circuit 260, or may be included in the circuit 260.

Further, the memory 262 may be an aggregate of a plurality of electronic circuits or may be configured by a plurality of sub memories. The memory 262 may be a magnetic disk or an optical disk, or may be expressed as a storage or a recording medium. Further, the memory 262 may be a nonvolatile memory or a volatile memory.

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

In addition, the memory 262 may store a bit string corresponding to the encoded moving image, or may store a decoded moving image. The memory 262 may store a program for the circuit 260 to decode a moving image.

Note that in the decoding device 200, all of the plurality of components shown in FIG. 10 may not be implemented, and all of the plurality of processes described above may not be performed. Some of the plurality of components illustrated in FIG. 10 may be included in another device, and some of the plurality of processes described above may be performed by another device. Then, in the decoding device 200, a part of the plurality of components shown in FIG. 10 is implemented, and a part of the plurality of processes described above is performed, so that the processing delay can be suppressed.

FIG. 22 is a flowchart showing an operation example of the decoding device 200 shown in FIG. For example, the circuit 260 in the decoding device 200 performs the operation illustrated in FIG. 22 using the memory 262, so that the decoding device 200 performs inter prediction in decoding of the decoding target block constituting the moving image.

Specifically, when performing the first process, the circuit 260 performs inter prediction of the decoding target block without performing one or more processes including the second process (S401). Here, the first process is a process of correcting the prediction image of the decoding target block using the luminance around the decoding target block and the luminance around the reference block. The second process is a process of correcting the predicted image using the spatial gradient of luminance obtained from the reference block.

Thereby, when performing the first process that is assumed to have a long processing time, the decoding apparatus 200 does not perform one or more processes including the second process that is assumed to have a long processing time, similarly to the first process. In addition, inter prediction can be performed. Therefore, the decoding apparatus 200 can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

For example, the one or more processes described above include a third process for correcting a predicted image using a reference image pointed to by a decoding target block using motion vectors of decoded blocks around the decoding target block. Also good. Thereby, when performing the first process, the decoding apparatus 200 can perform the inter prediction without performing the second process and the third process. Therefore, the decoding apparatus 200 can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

Further, for example, the one or more processes described above may be all processes different from the first process among a plurality of processes for correcting the predicted image. Thereby, when performing the first process, the decoding apparatus 200 can perform the inter prediction without performing the correction process other than the first process. Therefore, the decoding apparatus 200 can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

Further, for example, the circuit 260 may end the inter prediction of the decoding target block without correcting the prediction image after the first process is performed. Thereby, when performing the first process, the decoding apparatus 200 can perform the inter prediction without performing the correction process after the first process. Therefore, the decoding apparatus 200 can shorten the processing time of the stage including the first process, and can suppress a processing delay in decoding the moving image.

For example, the circuit 260 may determine whether or not to decode the decoding target block in the low delay mode. Then, when it is determined that the decoding target block is to be decoded in the low delay mode, the circuit 260 performs the inter prediction of the decoding target block without performing one or more of the above processes when performing the first process. May be. Thereby, in the low delay mode, the decoding apparatus 200 can shorten the processing time of the stage including the first processing, and can suppress the processing delay in the decoding of the moving image.

In addition, for example, the circuit 260 indicates information indicating whether or not decoding of the decoding target block is performed in the low-delay mode as a sequence header area, a picture header area, a tile header area, a slice header area, Decoding may be performed from at least one of the auxiliary information areas. Thereby, the decoding apparatus 200 can obtain information on whether or not the low-delay mode is set from the encoding apparatus 100.

Further, for example, the circuit 260 may determine whether or not to decode the decoding target block in the low delay mode according to the profile or level information assigned to the encoded stream of the moving image. Thereby, the decoding apparatus 200 can control whether to perform decoding in the low-delay mode adaptively according to the profile or level.

[Supplement]
Encoding apparatus 100 and decoding apparatus 200 in the present embodiment can be used as an image encoding apparatus and an image decoding apparatus, respectively. Alternatively, the encoding device 100 and the decoding device 200 can each be used as an inter prediction device. That is, the encoding apparatus 100 and the decoding apparatus 200 may support only the inter prediction unit 126 and the inter prediction unit 218, respectively.

In the above description, the processing corresponding to the processing target block, the processed block, the processed peripheral block, and the like is, for example, LIC processing, and specifically, processing for correcting a predicted image using a luminance correction parameter. It may be. Further, this process may be a stage process including a process of correcting a predicted image using a luminance correction parameter. Further, the processed block and the processed peripheral block may be blocks that have been processed by skipping the process.

In addition, the range corresponding to the periphery of the block may be a range adjacent to the block or a range of a predetermined number of pixels from the block.

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

Specifically, each of the encoding device 100 and the decoding device 200 includes a processing circuit (Processing Circuit) and a storage device (Storage) electrically connected to the processing circuit and accessible from the processing circuit. You may have. For example, the processing circuit corresponds to the circuit 160 or 260, and the storage device corresponds to the memory 162 or 262.

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

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

For example, this program is a coding method for performing inter prediction in coding of a coding target block constituting a moving image on a computer, and includes a luminance around the coding target block and a luminance around a reference block. One or more including a second process for correcting the predicted image using a spatial gradient of luminance obtained from the reference block when performing the first process of correcting the predicted image of the encoding target block using The encoding method for performing the inter prediction of the encoding target block may be executed without performing the above process.

In addition, for example, this program is a decoding method for performing inter prediction in decoding of a decoding target block constituting a moving image, using a luminance around the decoding target block and a luminance around a reference block. When performing the first process of correcting the predicted image of the decoding target block, one or more processes including a second process of correcting the predicted image using a spatial gradient of luminance obtained from the reference block are performed. You may make the decoding method which performs the inter prediction of the said decoding object block perform without performing.

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

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

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

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

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

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

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

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

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

[Example of use]
FIG. 23 is a diagram showing an overall configuration of a content supply system ex100 that implements a content distribution service. The communication service providing area is divided into desired sizes, and base stations ex106, ex107, ex108, ex109, and ex110, which are fixed wireless stations, are installed in each cell.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Alternatively, the picture may be divided into tiles or the like according to the meaning of the object in the image, and the decoding side may select only a part of the region by selecting the tile to be decoded. Also, by storing the object attributes (person, car, ball, etc.) and the position in the video (coordinate position in the same image, etc.) as meta information, the decoding side can determine the position of the desired object based on the meta information. Can be identified and the tile containing the object can be determined. For example, as shown in FIG. 25, the meta information is stored using a data storage structure different from the pixel data such as the SEI message in HEVC. This meta information indicates, for example, the position, size, or color of the main object.

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

[Web page optimization]
FIG. 26 is a diagram showing an example of a web page display screen on the computer ex111 or the like. FIG. 27 is a diagram illustrating a display screen example of a web page on the smartphone ex115 or the like. As shown in FIGS. 26 and 27, the web page may include a plurality of link images that are links to the image content, and the appearance differs depending on the browsing device. When a plurality of link images are visible on the screen, the display device until the user explicitly selects the link image, or until the link image approaches the center of the screen or the entire link image enters the screen. The (decoding device) displays a still image or an I picture included in each content as a link image, displays a video like a gif animation with a plurality of still images or I pictures, or receives only a base layer to receive a video. Are decoded and displayed.

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

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

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

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

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

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

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

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

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

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

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

[Hardware configuration]
FIG. 28 is a diagram illustrating the smartphone ex115. FIG. 29 is a diagram illustrating a configuration example of the smartphone ex115. The smartphone ex115 receives the antenna ex450 for transmitting and receiving radio waves to and from the base station ex110, the camera unit ex465 capable of taking video and still images, the video captured by the camera unit ex465, and the antenna ex450. A display unit ex458 for displaying data obtained by decoding the video or the like. The smartphone ex115 further includes an operation unit ex466 that is a touch panel or the like, a voice output unit ex457 that is a speaker or the like for outputting voice or sound, a voice input unit ex456 that is a microphone or the like for inputting voice, and photographing. Memory unit ex467 that can store encoded video or still image, recorded audio, received video or still image, encoded data such as mail, or decoded data, and a user, and network A slot part ex464, which is an interface part with the SIMex 468 for authenticating access to various data. An external memory may be used instead of the memory unit ex467.

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

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

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

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

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

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

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

DESCRIPTION OF SYMBOLS 100 Coding apparatus 102 Division | segmentation part 104 Subtraction part 106 Conversion part 108 Quantization part 110 Entropy encoding part 112,204 Inverse quantization part 114,206 Inverse conversion part 116,208 Adder 118,210 Block memory 120,212 Loop filter Unit 122, 214 frame memory 124, 216 intra prediction unit 126, 218 inter prediction unit 128, 220 prediction control unit 160, 260 circuit 162, 262 memory 200 decoding device 202 entropy decoding unit

Claims (18)

An encoding device that performs inter prediction in encoding of an encoding target block constituting a moving image,
Circuit,
With memory,
The circuit uses the memory,
When performing the first process of correcting the prediction image of the encoding target block using the luminance around the coding target block and the luminance around the reference block, a spatial gradient of the luminance obtained from the reference block An encoding device that performs inter prediction of the encoding target block without performing one or more processes including a second process of correcting the prediction image using the encoding. The one or more processes include a third process of correcting the prediction image using a reference image pointed to by the encoding target block using a motion vector of an encoded block around the encoding target block. The encoding apparatus according to claim 1. The encoding device according to claim 1, wherein the one or more processes are all processes different from the first process among a plurality of processes for correcting the predicted image. The encoding device according to any one of claims 1 to 3, wherein the circuit ends inter prediction of the encoding target block without correcting the prediction image after the first processing is performed. The circuit determines whether or not the encoding target block is encoded in the low delay mode, and when it is determined that the encoding target block is encoded in the low delay mode, The encoding device according to any one of claims 1 to 4, wherein when performing processing, inter prediction of the encoding target block is performed without performing the one or more processing. The circuit includes information indicating whether or not the encoding target block is to be encoded in the low-delay mode, a sequence header area, a picture header area, a tile header area, and a slice header area in the encoded stream of the moving image The encoding apparatus according to claim 5, wherein encoding is performed on at least one of the auxiliary information area. The code according to claim 5 or 6, wherein the circuit determines whether or not the encoding target block is to be encoded in the low delay mode according to a size of an encoding target picture including the encoding target block. Device. The encoding device according to claim 5 or 6, wherein the circuit determines whether to perform encoding of the encoding target block in the low delay mode according to a processing capability of a decoding device. The circuit according to claim 5 or 6, wherein the circuit determines whether or not the encoding target block is to be encoded in the low delay mode according to profile or level information assigned to the encoded stream of the moving image. Encoding device. A decoding device that performs inter prediction in decoding of a decoding target block constituting a moving image,
Circuit,
With memory,
The circuit uses the memory,
When performing the first process of correcting the predicted image of the decoding target block using the luminance around the decoding target block and the luminance around the reference block, a spatial gradient of luminance obtained from the reference block is used. A decoding device that performs inter prediction on the decoding target block without performing one or more processes including a second process for correcting the predicted image. The one or more processes include a third process of correcting the predicted image using a reference image pointed from the decoding target block by using a motion vector of a decoded block around the decoding target block. The decoding device according to 10. The decoding device according to claim 10 or 11, wherein the one or more processes are all processes different from the first process among a plurality of processes for correcting the predicted image. The decoding device according to any one of claims 10 to 12, wherein the circuit ends the inter prediction of the decoding target block without correcting the prediction image after the first process is performed. When the circuit determines whether to decode the decoding target block in the low delay mode, and performs the first process when it is determined that the decoding target block is decoded in the low delay mode The decoding device according to any one of claims 10 to 13, wherein inter prediction of the decoding target block is performed without performing the one or more processes. The circuit includes information indicating whether the decoding target block is to be decoded in the low delay mode, a sequence header area, a picture header area, a tile header area, a slice header area, and an auxiliary information in the moving image encoded stream. The decoding device according to claim 14, wherein decoding is performed from at least one of the information areas. The decoding device according to claim 14 or 15, wherein the circuit determines whether or not to decode the decoding target block in the low delay mode according to profile or level information assigned to the encoded stream of the moving image. . An encoding method for performing inter prediction in encoding of an encoding target block constituting a moving image,
When performing the first process of correcting the prediction image of the encoding target block using the luminance around the coding target block and the luminance around the reference block, a spatial gradient of the luminance obtained from the reference block An encoding method that performs inter prediction of the encoding target block without performing one or more processes including a second process of correcting the predicted image using the method. A decoding method for performing inter prediction in decoding of a decoding target block constituting a moving image,
When performing the first process of correcting the predicted image of the decoding target block using the luminance around the decoding target block and the luminance around the reference block, a spatial gradient of luminance obtained from the reference block is used. A decoding method that performs inter prediction of the decoding target block without performing one or more processes including a second process for correcting the predicted image.

Images