RU2777967C1 - Deblocking filter for the boundaries of subsections that arise under the influence of the intra-subsection coding tool - Google Patents

Abstract

FIELD: imaging technology.

SUBSTANCE: invention relates to means for image processing. The first maximum filter length is determined as equal to 1 for the first subsection and/or the second maximum filter length is determined as equal to 1 for the second subsection when the width of the first subsection is 4 samples or the width of the second subsection is 4 samples, or when the height of the first subsection is 4 samples or the height of the second subsection is 4 samples. Modification is performed based, at least partially, on the first maximum length of the filter, values of no more than one sample of the first subsection, while this sample in the number of no more than one is obtained from a row or column of the first subsection that are perpendicular and adjacent to the border of subsections between the first subsection and the second subsection. The modification is performed based, at least partially, on the second maximum length of the filter, the values of no more than one sample of the second subsection, while this sample, including no more than one, is obtained from a row or column of the second subsection that are perpendicular and adjacent to the border of the subsections between the first subsection and the second subsection.

EFFECT: increase the efficiency of video coding.

31 cl, 21 dwg

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority under U.S. Provisional Patent Application No. 62/791,003, filed January 10, 2019. The disclosure of the above patent application is incorporated herein by reference in its entirety.

FIELD OF TECHNOLOGY

Embodiments of the present disclosure relate generally to the field of image processing and, in particular, to a deblocking (deblocking) filter for subsection boundaries resulting from an intra subsection (ISP) encoding tool.

BACKGROUND OF THE INVENTION

Video encoding (video encoding and decoding) is used in a wide range of digital video applications, such as digital television broadcast, video transmission over the Internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray disc, systems for collecting and editing video content, as well as video cameras for security applications.

The amount of video data required to represent even a relatively short video can be significant, which can lead to difficulties when the data is to be streamed or otherwise transmitted over a limited bandwidth communication network. Thus, video data is typically compressed before being transmitted over modern telecommunication networks. Video size can also be an issue when the video is stored on a storage device, as memory resources can be limited. Video compression devices often use source software and/or hardware to encode video data prior to transmission or storage, thereby reducing the amount of data required to represent digital video images. The compressed data is then received by the receiver's video decompressor, which decodes the video data. With limited network resources and ever-increasing demands for higher video quality, improved compression and decompression techniques are desirable that improve compression rates with little or no loss in image quality.

In particular, in the context of intra prediction, an intra subsection (ISP) coding tool has recently been introduced in which an image block (such as a transform unit (TU), prediction unit (PU), coding unit (CU)) is divided into a plurality of subsections. However, intra-subsection (ISP) can cause inhomogeneities in sample values at subsection boundaries, thereby causing unwanted edge or boundary artifacts that are visible to the viewer. The goal of block image coding is to reduce edge artifacts below a visibility threshold. This is done by performing deblocking filtering. Such deblocking filtering is performed on the one hand on the decoding side to remove visible edge artifacts, but also on the encoding side to prevent any edge artifacts from being encoded into the image.

Thus, there is a need for an improved in-loop deblocking filter method and apparatus that effectively removes blocking artifacts that may be produced by an intra-subsection encoding tool.

SUMMARY OF THE INVENTION

In view of the above problems, embodiments of the present application are directed to providing a deblocking filter device, an encoder, a decoder, and corresponding methods that can mitigate or even completely eliminate blocking artifacts that may be caused by an intra-subsection encoding tool to improve encoding efficiency.

Embodiments of the invention are defined by the features of the independent claims, and additional advantageous implementations of the embodiments are defined by the features of the dependent claims.

Specific embodiments are set forth in the appended independent claims, and other embodiments are set forth in the dependent claims.

The above and other objects are achieved by the invention according to the independent claims. Additional forms of implementation are apparent from the dependent claims, description and figures.

According to a first aspect of the present disclosure, a deblocking method is provided for deblocking a subsection boundary in a coding block in image encoding and/or image decoding, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection, which is adjacent to the first subsection (for example, the second subsection is in the right or lower block relative to the first subsections). In the example, the second subsection is intra-predicted based on the first subsection (i.e. the current coding block is encoded using the intra subdivision tool, ISP, or the subsection boundary occurs under the action of the intra subdivision tool, ISP, in particular, the current coding block is divided into subsections by means of the encoding tool, ISP and intra-subsections are intra-predicted one after the other, for example, from left to right or from top to bottom); wherein the method comprises:

- defining a first maximum filter length of 1 for the first subsection and/or a second maximum filter length of 1 for the second subsection when the width of the first subsection is 4 samples or the width of the second subsection is 4 samples or when the height of the first subsection is 4 samples or the height of the second subsection is 4 samples;

- modifying (i.e. filtering) the value of at most one sample of the first subsection, wherein this sample of at most one is obtained from a row or column of the first subsection that is perpendicular to and adjacent to the subsection boundary between the first subsection and the second subsection; and/or

- modifying (i.e. filtering) the value of at most one sample of the second subsection, wherein this sample of at most one is obtained from a row or column of the second subsection that is perpendicular to and adjacent to the subsection boundary between the first subsection and the second subsection.

It can be understood that the first maximum filter length for the first subsection may mean, in each row or column that is perpendicular to and adjacent to the subsection boundary, the maximum number of samples allowed for modification for the first subsection. The second maximum filter length for the second subsection may mean, in each row or column that is perpendicular to and adjacent to the subsection boundary, the maximum number of samples allowed to be modified for the second subsection. It can be understood that, depending on the particular phase of the filtering decision, in some cases no sample may be modified, or in other cases only one sample may be modified in each/th row or column perpendicular/s and adjacent to the boundary. subsections.

The invention works for both vertical and horizontal subsection borders. For a vertical border of subsections, the width of the first or second subsection is checked to see if that width is equal to 4 samples. For a horizontal subsection boundary, the height of the first or second subsection is checked to see if that height is equal to 4 samples.

It should be noted that in this disclosure, the terms "block", "coding block" or "image block" are used, which can be applied to prediction units (PU), coding units (CU), etc. In VVC as a whole, transformation units and coding units are mostly aligned except in a few scenarios when TU tiling, subblock transform (SBT) or ISP is used. It can be understood that the terms "block/image block/coding block" can be used interchangeably in the present disclosure. The terms "sample/pixel" may be used interchangeably in the present disclosure.

The intra-subsection encoding tool divides the intra-prediction block (i.e., the intra-coding block, which is an abbreviation for the current coding block that is encoded in the intra-prediction mode) into subsections, and predicts the subsections within one by one. There may be heterogeneity at the subsection boundary. An improved filtering process is proposed to reduce the artifact caused by these subsection boundaries, wherein filtering at most one sample is performed on the first or second subsection when the height of the first or second subsection is 4 samples, or when the width of the first or second subsection is 4 samples. This allows a small number of sample values to be modified at a subsection boundary, and therefore the method can reduce blocking artifacts that are caused by subsection boundaries in the current coding block due to the application of ISP. Such weak filtering is beneficial in terms of computational load.

In a possible form of implementation of the method according to the first aspect as such, a sample of at most one, which is obtained from the column of the first or second subsection, which is perpendicular to and adjacent to the border between the first and second subsections, is modified when the height of the first or second subsection is 4 samples if the intra-subpartitioning type for subdividing the current coding block into subsections is horizontal. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no selection may be modified, or in other cases only one selection may be modified in each column perpendicular to and adjacent to the subsection boundary.

In a possible form of implementation of the method according to the first aspect as such, a sample of at most one, which is obtained from the line of the first or second subsection, which is perpendicular to and adjacent to the border between the first and second subsections, is modified when the width of the first or second subsection is 4 samples if the intra-subpartitioning type for subdividing the current coding block into subsections is vertical. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no selection may be modified, or in other cases only one selection may be modified in each row perpendicular to and adjacent to the subsection boundary.

In an exemplary form of implementation of the method according to any previous implementation of the first aspect, or the first aspect as such, if the type of intra-subpartitioning for subdividing the current coding block into subsections is horizontal, the subsection boundary between the first and second subsections is a horizontal subsection boundary; Alternatively, if the type of intra-subsection for dividing the current coding block into subsections is vertical, the subsection boundary between the first and second subsections is a vertical subsection boundary.

In an exemplary form of implementation of the method according to any prior implementation of the first aspect, or the first aspect as such, if the intra-subsection type for subdividing the current coding block into subsections is vertical, the first subsection may be to the left of the second subsection and the second subsection may be intra-predicted based on the restored value (for example, the restored version) of the first subkey;

if the type of intra-subpartitioning for subdividing the current coding block into subsections is horizontal, the first subsection may be on top of the second subsection, and the second subsection may be intra-predicted based on a restored value (eg, restored version) of the first subsection.

It can be understood that the second subsection is intra-predicted based on the reconstructed version (ie, recovered values) of the first subsection. The reconstructed first subsection is a pivot for intra-prediction of the second subsection. It should be noted that after restoring the current image to which the current coding block belongs, the restored image is entered into the filtering process. During the reconstruction of the current picture, the current coding block to which the ISP coding tool is applied is intra-predicted to obtain a predictive block (eg, predicted values) of the current coding block, in particular, subsections within the current intra coding block are intra-predicted one by one.

In an exemplary form of implementation of the method according to any previous implementation of the first aspect, or the first aspect as such, the number of subsections is 2 or 4.

In a possible form of implementation of the method according to any previous implementation of the first aspect or the first aspect as such,

- if the width of the current coding block is 4 and the height of the coding block is 8 and/or if the width of the current coding block is 8 and the height of the current coding block is 4, the number of subsections is 2,

- otherwise the number of subsections is 4.

In an exemplary form of implementation of the method according to any prior implementation of the first aspect, or the first aspect as such, a sample of at most one in the first or second subsection is modified even if the subsection boundary between the first and second subsections does not overlap with an n x n grid of samples, where n is an integer .

It is possible to release target boundaries that are not aligned with the n x n grid, but are called by the ISP and represent an internal boundary between subsections of a coding block.

In an exemplary form of implementation of the method according to any prior implementation of the first aspect, or the first aspect as such, a sample of at most one in the first or second subsection is modified only if the subsection boundary between the first and second subsections overlaps with an n x n grid of samples, where n is an integer, for example n=4 or n=8. Thus, the computational load can be further reduced.

Moreover, filtering at most one selection in subsections can only be performed when all subsections are 4 selections high, or when all subsections are 4 selections wide. Thus, the computational load of the entire encoding process can be further reduced.

In general, subsections may be rectangular subsections of a transform block.

In an exemplary form of implementation of the method according to any prior implementation of the first aspect, or the first aspect as such, the subsection samples are luminance samples or the subsection samples are chrominance samples.

In an exemplary form of implementation of the method according to any prior implementation of the first aspect, or the first aspect as such, the intra-subsection prediction order is left-to-right order if the intra-subsection partitioning type for dividing the current coding block into subsections is vertical, or the intra-subsection prediction order is the order from top to bottom if the type of intra-subpartitioning for subdividing the current coding block into subsections is horizontal. That is, division of the prediction block into subsections can be performed in the vertical direction. In this case, the intra-subsection order is the order one after the other, from left to right. Alternatively, division of the prediction block into subsections may be performed in the horizontal direction. In this case, the intra-prediction order of the two subsections is the order one after the other, from top to bottom.

In the present disclosure, the current coding block is encoded using the intra-subdivision tool, ISP, or a subsection boundary occurs under the action of the intra-subdivision tool, ISP.

In general, the border intensities of all borders between subsections of a coding block may be set to a constant value indicating the strength of the filtering process (eg, 2) to simplify overall processing.

Furthermore, in the embodiments described above, the method may comprise obtaining encoded block flag values, CBF, corresponding to two adjacent subsections, determining a boundary strength between two adjacent subsections of the current block according to the CBF values corresponding to the two adjacent subsections, and

making a filtering decision whether to perform filtering according to the defined boundary intensity. At least one of the CBF values corresponding to two adjacent subsections may not be 0, where 0 means that there is no residual data after quantization of that subsection.

According to a second aspect of the present disclosure, a deblocking method is provided for deblocking block edges between image blocks in image encoding and/or image decoding, wherein the block edges comprise an edge between the current subsection of the current coding block (i.e., the current intra coding block) and an adjacent block. of this current coding block, wherein the current coding block is encoded in intra-prediction mode and the current coding block is subdivided (either the current coding block is encoded using the intra subdivision tool, ISP, or the subsections are generated by the intra subdivision tool, ISP) ; wherein the method comprises:

- defining a third maximum filter length equal to 1 for the current subsection and/or a fourth maximum filter length equal to 1 for the neighboring block, when the width of the current subsection is 4 samples or the height of the current subsection is 4 samples;

- modifying the value of at most one sample of the current subsection, wherein this sample of at most one is obtained from a row or column of the current subsection that is perpendicular to and adjacent to the edge between the current subsection and the adjacent block; and/or

- modifying the value of at most one neighboring block sample, wherein this sample of at most one is obtained from a row or column of the neighboring block that is perpendicular and adjacent to the edge between the current subsection and the neighboring block.

It should be noted that if the number of subsections is two, the current subsection may be the first subsection or the second subsection according to the first aspect as such. If the number of subsections is greater than two, such as four, the current subsection may be the leftmost subsection or the rightmost subsection within the current coding block if the intra-subsectioning type for dividing the current coding block into subsections is vertical, or the current subsection may be the topmost subsection or the lowest subsection within the current coding block if the intra-subsection type for dividing the current coding block into subsections is horizontal.

In a second aspect of the present disclosure, the current subsection is intra-predicted based on an adjacent block that is adjacent to the top or left. It should be noted that the adjacent block may not be a coding block with additional sections, i.e., the adjacent block is likely to have no subsection.

It can be understood that the third maximum filter length for the current subsection may mean, in each row or column that is perpendicular and adjacent to the edge, the maximum number of samples allowed for modification for the current subsection. The fourth maximum filter length for a neighboring block may mean, in each row or column that is perpendicular and adjacent to an edge, the maximum number of samples allowed for modification for the neighboring block. It can be understood that, depending on the particular phase of the filtering decision, in some cases no sample may be modified, or in other cases only one sample may be modified in each/th row or column perpendicular/s and adjacent to the boundary. subsections.

The invention works for both the vertical and horizontal edges between the current subsection and the adjacent box. For the vertical edge, the width of the current subsection or adjacent box is checked to see if that width is 4 samples. For a horizontal edge, the height of the current subsection or neighboring box is checked to see if that height is equal to 4 samples.

The difference between a block edge and a subsection border is described in the following description. A subsection boundary is an edge that is internal to a coding block in which intra-subsection (ISP) encoding tools are used, and a block edge (i.e. a coding unit (CU) edge or a coding block edge or a CU boundary) is the edge , which is shared between two coding units or two coding units.

The intra-subsection encoding tool divides the intra-prediction block (i.e., the intra-coding block, which is the short name for the current coding block that is encoded in intra-prediction mode) into subsections, and predicts the subsections within the intra-prediction block one by one . There may be discontinuity at the edge between the current subsection of the current coding block and an adjacent block of the current coding block. Therefore, an improved filtering process is proposed to reduce the artifact caused by such an edge in which no more than one sample is filtered in the current subsection or adjacent block when the height of the current subsection is 4 samples or the width of the current subsection is 4 samples. This allows a small number of sample values to be modified at the edge and therefore the method can reduce blocking artifacts that may be caused by said edge between the current box to which the ISP is applied and the adjacent box, while avoiding filtering overlaps between the edge and the subsection boundary to a certain extent. degree.

In a possible form of implementation of the method according to the second aspect as such,

a sample of at most one that is obtained from a column of the current subsection that is perpendicular to and adjacent to the edge between the current subsection and an adjacent block that is below or above the current subsection is modified when the height of the current subsection is 4 samples if the partition type is intra-subsections to divide the current coding block into subsections is horizontal. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no sample may be modified, or in other cases only one sample may be modified in each column perpendicular and adjacent to the edge.

In a possible form of implementation of the method according to the second aspect as such,

a sample of at most one that is obtained from a row of the current subsection that is perpendicular to and adjacent to the edge between the current subsection and an adjacent box that is to the left or right of the current subsection is modified when the width of the current subsection is 4 samples if the split type is intra-subsections to divide the current coding block into subsections is vertical. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no sample may be modified, or in other cases only one sample may be modified in each line perpendicular to and adjacent to an edge.

In an exemplary implementation form of the method according to any prior implementation of the second aspect, or the second aspect as such, if the intra-subsection type for subdividing the current coding block into subsections is vertical, the current subsection is to the right of the adjacent block, and the current subsection is intra-predicted based on the reconstructed neighbor block values;

if the type of intra-subpartitioning for dividing the current coding block into subsections is horizontal, the current subsection is below the neighboring block, and the current subsection is intra-predicted based on the recovered value of the neighboring block.

The current subsection may be intra-predicted based on another coding block that is adjacent to the coding block. This other coding block may be on top of the coding block or to the left of the coding block. More precisely, the current subsection may be intra-predicted based on a reconstructed version of an adjacent coding block.

In an exemplary form of implementation of the method according to any prior implementation of the second aspect, or the second aspect as such, the number of subsections is 2 or 4.

In a possible form of implementation of the method according to any previous implementation of the second aspect or the second aspect as such,

- if the width of the current coding block is 4 and the height of the coding block is 8 and/or if the width of the current coding block is 8 and the height of the current coding block is 4, the number of subsections is 2,

- otherwise the number of subsections is 4.

In an exemplary form of implementation of the method according to any prior implementation of the second aspect, or the second aspect per se, a sample of at most one in the current subsection or adjacent block is modified even if the edge between the current subsection and the adjacent block does not overlap with an n x n grid of samples, where n is integer. For example, n=4 or n=8.

In an exemplary form of implementation of the method according to any prior implementation of the second aspect, or the second aspect as such, a sample of at most one in the current subsection or adjacent block is modified only if the edge between the current subsection and the adjacent block overlaps with an n x n grid of samples, where n is an integer number. For example, n=4 or n=8.

In an exemplary embodiment of the method according to any prior implementation of the second aspect, or the second aspect as such, the subsection samples are luminance samples or the subsection samples are chrominance samples.

In an exemplary form of implementation of the method according to any prior implementation of the second aspect, or the second aspect as such, the subsections are rectangular subsections of the transform block.

In an exemplary form of implementation of the method according to any prior implementation of the second aspect, or the second aspect per se, the current coding block is encoded using an intra-partitioning tool, ISP.

According to a third aspect of the present disclosure, an apparatus is provided for use in an image encoder and/or image decoder to deblock a subsection boundary in a coding block, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection. , which is adjacent to the first subsection, wherein the second subsection is intra-predicted based on the first subsection;

wherein the device comprises a deblocking filter configured to:

- defining a first maximum filter length of 1 for the first subsection and/or a second maximum filter length of 1 for the second subsection when the first subsection is 4 samples wide or the second subsection is 4 samples wide or when the first subsection is 4 samples high or the second subsection is height subsection is 4 samples;

- modifying the value of at most one sample of the first subsection, whereby that sample of at most one is obtained from a row or column of the first subsection that is perpendicular to and adjacent to the subsection boundary between the first subsection and the second subsection; and/or

- modifications to the value of at most one sample of the second subsection, whereby this sample of at most one is obtained from a row or column of the second subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection.

According to a fourth aspect of the present disclosure, an apparatus is provided for use in an image encoder and/or image decoder for deblocking block edges between image blocks, wherein the block edges comprise an edge between a current subsection of a current coding block and an adjacent block of that current coding block, wherein the current coding block encoded in intra-prediction mode, and the current coding block is divided into subsections;

wherein the device comprises a deblocking filter configured to:

- determining a third maximum filter length equal to 1 for the current subsection and/or a fourth maximum filter length equal to 1 for the neighboring block, when the width of the current subsection is 4 samples or the height of the current subsection is 4 samples;

- modifying the value of at most one sample of the current subsection, wherein this sample of at most one is obtained from a row or column of the current subsection that is perpendicular to and adjacent to the edge between the current subsection and the adjacent block; and/or

- modifications to the value of at most one neighboring block sample, whereby at most one sample is obtained from a neighboring block row or column that is perpendicular to and adjacent to the edge between the current subsection and the neighboring block.

The method according to the first aspect of the invention can be performed by the device according to the third aspect of the invention. Additional features and implementations of the device according to the third aspect of the invention correspond to the features and implementations of the method according to the first aspect of the invention.

The method according to the second aspect of the invention can be performed by the device according to the fourth aspect of the invention. Additional features and implementations of the device according to the fourth aspect of the invention correspond to the features and implementations of the method according to the second aspect of the invention.

According to a fifth aspect, the invention relates to a device for decoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the first or second aspect.

According to a sixth aspect, the invention relates to a device for encoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the first or second aspect.

According to a seventh aspect, a computer-readable medium is provided that stores instructions that, when executed, operate one or more processors capable of encoding video data. The instructions cause one or more processors to execute a method according to the first or second aspect, or any possible embodiment of the first or second aspect.

According to an eighth aspect, the invention relates to a computer program containing program code for performing the method according to the first or second aspect, or any possible embodiment of the first or second aspect, when executed on a computer.

According to a ninth aspect, the invention relates to an encoder or decoder comprising a processing circuit for performing a method according to the first or second aspect, or any possible embodiment of the first or second aspect.

According to a tenth aspect of the invention, a video encoding device is provided. A video encoding device for encoding an image of a video stream, wherein the video encoding device comprises:

a restoration block configured to restore the image, wherein the image restoration comprises generating a restored block of the current coding block that belongs to the image, the current coding block being encoded in intra-prediction mode and the current coding block being divided into subsections containing a first subsection and a second subsection , wherein the second subsection is intra-predicted based on the first subsection; and

a filtering unit configured to process the reconstructed image into a filtered reconstructed image, wherein the filtering unit is specifically configured to filter at most one sample in the current subsection from the reconstructed subsections of the reconstructed block, when the height of the current subsection or another subsection that is adjacent to the current subsection , is 4 samples, or when the width of the current sub-section or another sub-section that is adjacent to the current sub-section is 4 samples, and at most one said sample is located in a row or column of the current sub-section that is perpendicular to the boundary between the current sub-section and said other a subsection that is adjacent to the current subsection and that one sample is adjacent to a boundary, or wherein the filter block is particularly configured to filter the boundary between the current subsection of the reconstructed block and an adjacent block that is adjacent to the current subsection, based on the corresponding maximum filter length for the current subsection and the corresponding maximum filter length for the neighboring block, and both of these corresponding maximum filter lengths are 1 when the height of the current subsection is 4 samples or when the width of the current subsection is 4 samples.

This allows you to effectively improve the quality of restored images within the ISP.

In a possible implementation, a sample of at most one that is obtained from a column of the first or second subsection that is perpendicular to and adjacent to the boundary between the first and second subsections is modified when the height of the first or second subsection is 4 samples if the partition type is intra- subsections to divide the current coding block into subsections is horizontal. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no selection may be modified, or in other cases only one selection may be modified in each column perpendicular to and adjacent to the subsection boundary.

In a possible implementation, a sample of at most one that is obtained from a row of the first or second subsection that is perpendicular to and adjacent to the boundary between the first and second subsections is modified when the width of the first or second subsection is 4 samples if the partition type is intra- subsections to divide the current coding block into subsections is vertical. It can be understood that "modification of a sample of at most one" may mean that modification of at most one sample is allowed. That is, depending on the particular filtering decision phase, in some cases no selection may be modified, or in other cases only one selection may be modified in each row perpendicular to and adjacent to the subsection boundary.

In an exemplary implementation form, if the intra-subsection type for subdividing the current coding block into subsections is horizontal, the subsection boundary between the first and second subsections is a horizontal subsection boundary; Alternatively, if the type of intra-subsection for dividing the current coding block into subsections is vertical, the subsection boundary between the first and second subsections is a vertical subsection boundary.

In an exemplary implementation, if the type of intra-subsection for subdividing the current coding block into subsections is vertical, the first subsection may be derived from the second subsection, and the second subsection may be intra-predicted based on the recovered value of the first subsection;

If the intra-subsection type for dividing the current coding block into subsections is horizontal, the first subsection may be on top of the second subsection, and the second subsection may be intra-predicted based on the recovered value of the first subsection.

It can be understood that the second subsection is intra-predicted based on the reconstructed version (ie, recovered values) of the first subsection. The reconstructed first subsection is a pivot for intra-prediction of the second subsection. It should be noted that after restoring the current image to which the current coding block belongs, the restored image is entered into the filtering process. During the reconstruction of the current picture, the current coding block to which the ISP coding tool is applied is intra-predicted to obtain a predictive block (eg, predicted values) of the current coding block, in particular, subsections within the current intra coding block are intra-predicted one by one.

In a possible implementation form, the number of subsections is 2 or 4.

In a possible form of implementation

- if the width of the current coding block is 4 and the height of the coding block is 8 and/or if the width of the current coding block is 8 and the height of the current coding block is 4, the number of subsections is 2,

- otherwise the number of subsections is 4.

In an exemplary implementation, a sample of at most one in the first or second subsection is modified even if the subsection boundary between the first and second subsections does not overlap with an n x n grid of samples, where n is an integer.

It is possible to release target boundaries that are not aligned with the n x n grid, but are called by the ISP and represent an internal boundary between subsections of a coding block.

In an exemplary implementation, a sample of at most one in the first or second subsection is modified only if the subsection boundary between the first and second subsections overlaps with an n x n grid of samples, where n is an integer, such as n=4 or n=8. Thus, the computational load can be further reduced.

Moreover, filtering at most one selection in subsections can only be performed when the height of all subsections is 4 selections, or when the width of all subsections is 4 selections. Thus, the computational load of the entire encoding process can be further reduced.

In general, subsections may be rectangular subsections of a transform block.

In a possible implementation form, the subsection samples are luma samples, or the subsection samples are chrominance samples.

In a possible implementation form, the intra-subsection prediction order is left-to-right order if the intra-subsection type for sub-dividing the current coding block is vertical, or the intra-subsection prediction order is top-down order if the intra-subsection type for dividing the current coding block into subsections is horizontal. That is, division of the prediction block into subsections can be performed in the vertical direction. In this case, the intra-subsection order is the order one after the other, from left to right. Alternatively, division of the prediction block into subsections may be performed in the horizontal direction. In this case, the intra-prediction order of the two subsections is the order one after the other, from top to bottom.

In the present disclosure, the current coding block is encoded using the intra-subdivision tool, ISP, or a subsection boundary occurs under the action of the intra-subdivision tool, ISP.

In general, the border intensities of all borders between subsections of a coding block may be set to a constant value indicating the strength of the filtering process (eg, 2) to simplify overall processing.

Moreover, values of the coded block flag, CBF, can be obtained according to two adjacent subsections, the boundary strength for the border is determined between these two adjacent subsections of the current block according to the CBF values corresponding to said two adjacent subsections, and

filtering decision whether or not to perform filtering can be performed according to the determined boundary intensity. At least one of the CBF values corresponding to two adjacent subsections may not be 0, where 0 means that there is no residual data after quantization of that subsection.

According to an eleventh aspect of the invention, a video decoding apparatus is provided. A video decoding device for decoding an image of an encoded video stream, wherein the video decoding device comprises:

a restoration block configured to restore an image, wherein the image restoration comprises generating a restored block of the current coding block that belongs to the current image, the current coding block being encoded in intra-prediction mode and the current coding block being divided into subsections containing a first subsection and a second subsection, wherein the second subsection is intra-predicted based on the first subsection; and

a filtering unit configured to process the reconstructed image into a filtered reconstructed image, wherein the filtering unit is specifically configured to filter at most one sample in the current subsection from the reconstructed subsections of the reconstructed block, when the height of the current subsection or another subsection that is adjacent to the current subsection , is 4 samples, or when the width of the current sub-section or another sub-section that is adjacent to the current sub-section is 4 samples, and at most one said sample is located in a row or column of the current sub-section that is perpendicular to the boundary between the current sub-section and said other a subsection that is adjacent to the current subsection and that one sample is adjacent to a boundary, or wherein the filter block is particularly configured to filter the boundary between the current subsection of the reconstructed block and an adjacent block that is adjacent to the current subsection, based on the corresponding maximum filter length for the current subsection and the corresponding maximum filter length for the neighboring block, and both of these corresponding maximum filter lengths are 1 when the height of the current subsection is 4 samples or when the width of the current subsection is 4 samples.

This allows you to effectively improve the quality of restored images within the ISP.

In addition, an encoder is provided, comprising means for encoding a current coding block of the current image, which means comprises means for generating a reconstructed block of the current coding block and means for filtering the reconstructed image of the current image according to any of the above-described embodiments of the methods of the present invention.

In addition, a decoder is provided, comprising means for decoding the current coding block of the current image, which means includes means for generating a reconstructed block of the current coding block and means for filtering the reconstructed image of the current image according to any of the above-described embodiments of the methods of the present invention.

Details of one or more embodiments are set forth in the accompanying drawings and in the following description. Other features, purposes and advantages will be apparent from the description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments, the invention is described in more detail with reference to the accompanying figures and drawings, in which:

FIG. 1A is a block diagram showing an example of a video coding system capable of implementing embodiments of the invention;

FIG. 1B is a block diagram showing another example of a video coding system capable of implementing embodiments of the invention;

FIG. 2 is a block diagram showing an example of a video encoder capable of implementing embodiments of the invention;

FIG. 3 is a block diagram showing an example of the structure of a video decoder capable of implementing embodiments of the invention;

FIG. 4 is a block diagram illustrating an example of an encoding device or a decoding device;

FIG. 5 is a block diagram illustrating another example of an encoding device or a decoding device;

FIG. 6 is a block diagram illustrating an example of subsection edge deblocking in a coding unit (CU) that uses an intra subdivision tool (ISP);

FIG. 7 is a block diagram illustrating another example of deblocking subsection edges in a CU that uses an intra-subdivision tool (ISP);

FIG. 8 is a block diagram illustrating an example of deblocking the edges of subsections in a CU that overlap with an 8×8 grid of samples;

FIG. 9 is a block diagram illustrating an example of deblocking all subsection edges in a CU that overlap with an 8x8 sample grid;

FIG. 10 is a flowchart illustrating an example that when the subsection size is <8 samples orthogonally in the deblocking direction, then a weak filter is used that uses only 3 samples in the deblocking decision and that only modifies one sample;

FIG. 11 shows a flowchart illustrating an exemplary process for deblocking filtering;

FIG. 12 shows a flowchart illustrating another exemplary process for deblocking filtering;

FIG. 13 shows a schematic representation of an apparatus for deblocking a subsection boundary in a coding block.

FIG. 14 shows a schematic representation of a block edge release device.

FIG. 15 shows a flowchart illustrating an exemplary encoding process implemented in a decoding device or an encoding device;

FIG. 16 shows a flowchart illustrating another exemplary encoding process implemented in a decoding device or an encoding device;

FIG. 17 shows a schematic representation of a video encoding device;

FIG. 18 shows a schematic representation of a video encoding device;

FIG. 19 is a block diagram showing an exemplary structure of a content supply system that implements a content delivery service; and

FIG. 20 is a block diagram showing the structure of an exemplary terminal device.

Like reference numerals hereinafter refer to identical or at least functionally equivalent features, unless expressly stated otherwise.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, reference is made to the accompanying drawings, which form part of this disclosure and which show, by way of illustration, specific aspects of embodiments of the invention or specific aspects in which embodiments of the present invention may be used. It is clear that embodiments of the present invention can be used in other aspects and contain structural or logical changes not shown in the figures. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

For example, it is understood that the disclosure associated with the described method may also be true for the corresponding device or system configured to perform the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more blocks, such as functional blocks, to perform the one or more method steps described (for example, one block performing one or more steps, or a plurality of blocks each of which performs one or more of a plurality of steps), even if such one or more blocks are not explicitly described or illustrated in the figures. On the other hand, for example, if a particular device is described in terms of one or more blocks, such as functional blocks, the corresponding method may include one step to perform the functionality of one or more blocks (for example, one step to perform the functionality of one or more blocks , or a plurality of steps, each of which performs the functionality of one or more of the plurality of blocks), even if such one or more steps are not explicitly described or illustrated in the figures. In addition, it is understood that features of the various exemplary embodiments and/or aspects described herein may be combined with one another unless specifically noted otherwise.

Video coding generally refers to the processing of a sequence of images that form a video or video sequence. Instead of the term "picture", the terms "frame" or "picture" may be used interchangeably in the field of video coding. Video encoding (or encoding in general) contains two parts: video encoding and video decoding. Video coding is performed at the source side and typically involves processing (eg, by compressing) the original video images to reduce the amount of data required to represent the video images (for more efficient storage and/or transmission). Video decoding is performed on the recipient (destination) side and usually contains inverse processing compared to the encoder for recovering video images. Embodiments relating to "coding" video images (or images in general) should be understood as referring to "coding" or "decoding" video images or corresponding video sequences. The combination of an encoding part and a decoding part is also called CODEC (encoding and decoding).

In the case of lossless video coding, the original video images can be reconstructed, i.e. the restored video images are of the same quality as the original video images (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, additional compression is performed, for example by quantization, to reduce the amount of data representing video images that cannot be fully reconstructed at the decoder, i.e. the quality of the restored video images is lower or worse than the quality of the original video images.

Several video coding standards belong to the group of "hybrid lossy video codecs" (ie, combine spatial and temporal sample-domain prediction and 2D transform coding to apply transform-domain quantization). Each picture of a video sequence is usually divided into a set of non-overlapping blocks, and encoding is usually done at the block level. In other words, in the encoder, the video is usually processed, that is, encoded, at the block (video block) level, for example, using spatial (intra-image) prediction and/or temporal (inter-image) prediction to generate a prediction block, the prediction block is subtracted from the current block (the block currently being processed/to be processed) to obtain a residual block, the residual block is transformed and this residual block is quantized in the transformation region to reduce the amount of data (compression) to be transmitted, while in the decoder the inverse processing compared to applied to the encoded or compressed block by the encoder to reconstruct the current block for presentation. In addition, the encoder duplicates the processing loop of the decoder so that they will both generate identical predictions (eg, intra- and inter-predictions) and/or reconstructions for processing, ie coding (coding), subsequent blocks.

In the following embodiments of video encoding system 10, video encoder 20 and video decoder 30 are described based on FIG. 1 to 3.

FIG. 1A is a schematic block diagram illustrating an exemplary coding system 10, such as a video coding system 10 (or coding system 10 for short), that may use the techniques of the present application. Video encoder 20 (or encoder 20 for short) and video decoder 30 (or decoder 30 for short) of video coding system 10 represent examples of devices that can be configured to perform methods in accordance with the various examples described herein.

As shown in FIG. 1A, the encoding system 10 includes a source device 12 configured to provide the encoded image data 21 to, for example, a destination device 14 for decoding the encoded image data 13.

Source device 12 includes an encoder 20 and may additionally, i. e. optionally, contain an image source 16, a preprocessor (or preprocessor) 18, such as an image preprocessor 18, and a communication interface or communication unit 22.

The image source 16 may comprise or be any type of image capturing device, such as a camera for capturing a real world image, and/or any type of image generating device, such as a computer graphics processor for generating a computer animated image, or any type of other device for capturing and/or providing a real-world image, a computer-generated image (eg, screen content, virtual reality (VR) image), and/or any combination thereof (eg, augmented reality (AR) image). The image source can be any type of memory or storage where any of the above images are stored.

Unlike the preprocessor 18 and the processing performed by the pre-processor 18, the image or image data 17 may also be referred to as a raw image or raw image data 17 .

The preprocessor 18 is configured to receive (raw) image data 17 and perform pre-processing on that image data 17 to obtain a pre-processed image 19 or pre-processed image data 19. The pre-processing performed by the preprocessor 18 may, for example, include cropping, color format conversion (eg from RGB to YCbCr), color correction or denoising. It should be understood that the pre-processing module 18 may be an optional component.

Video encoder 20 is configured to receive pre-processed image data 19 and provide encoded image data 21 (more details will be described below, for example, based on Fig. 2).

Communication interface 22 of source device 12 may be configured to receive encoded image data 21 and transmit this encoded image data 21 (or any further processed version thereof) over communication channel 13 to another device, such as a destination device 14 or any other device, for saving or immediate restoration.

Destination device 14 includes a decoder 30 (eg, video decoder 30) and may additionally, i. e. optionally, contain a communication interface or a communication unit 28, a postprocessor 32 (or a postprocessing unit 32) and a display device 34.

Communication interface 28 of sink device 14 is configured to receive encoded image data 21 (or any further processed version thereof), such as directly from source device 12 or from any other source, such as a storage device, such as an encoded image data storage device, and provide encoded image data 21 to the decoder 30.

Communication interface 22 and communication interface 28 may be configured to transmit or receive encoded image data 21 or encoded data 13 via a direct link between source device 12 and destination device 14, such as a direct wired or wireless connection, or over any type of network. , such as a wired or wireless network, or any combination thereof, or any private and public network, or any combination thereof.

The communication interface 22 may, for example, be configured to pack the encoded image data 21 into an appropriate format, such as packets, and/or process the encoded image data using any type of transmission coding or processing for transmission over a communication link or network.

The communication interface 28, which is analogous to the communication interface 22, may, for example, be configured to receive the transmitted data and process the transmission data using any kind of appropriate decoding or processing and/or decompressing the transmission to obtain encoded image data 21.

Both communication interface 22 and communication interface 28 may be implemented as unidirectional communication interfaces, as indicated by the arrow for communication channel 13 in FIG. 1A pointing from source device 12 to destination device 14, or as bi-directional communication interfaces, and can be configured to e.g. send and receive messages, e.g. to establish a connection, to acknowledge and exchange any other link related information. and/or data transmission, such as the transmission of encoded image data.

The decoder 30 is configured to receive encoded image data 21 and provide decoded image data 31 or decoded image 31 (more details will be described below, for example, based on Fig. 3 or Fig. 5).

The post processor 32 of the destination device 14 is configured to post-process the decoded image data 31 (also referred to as reconstructed image data), such as the decoded image 31, to obtain post-processed image data 33, such as the post-processed image 33. Post-processing performed by block 32 post-processing may include, for example, color format conversion (for example, from YCbCr to RGB), color correction, cropping or resampling, or any other processing, for example, to prepare the decoded image data 31 for display, for example, using the display device 34.

The display device 34 of the sink device 14 is configured to receive the post-processed image data 33 for displaying the image to, for example, a user or viewer. The display device 34 may be or include any type of display for presenting the reconstructed image, such as an integrated or external display or monitor. The displays may, for example, comprise liquid crystal displays (LCD), organic light emitting diode (OLED) displays, plasma displays, projectors, micro-LED displays, liquid crystal on silicon (LCoS), digital light processor (DLP), or any other type of display. .

Although Fig. 1A illustrates source device 12 and sink device 14 as separate devices, device embodiments may also comprise both or both functionality, source device 12 or related functionality, and sink device 14 or related functionality. In such embodiments, source device 12 or related functionality and sink device 14 or corresponding functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof. .

As will be apparent to those skilled in the art based on the description, the presence and (precise) separation of the functionality of the various blocks or functionality in source device 12 and/or sink device 14, as shown in FIG. 1A may vary depending on the actual device and application.

Encoder 20 (eg, video encoder 20) or decoder 30 (eg, video decoder 30) or both encoder 20 and decoder 30 may be implemented via a processing circuit as shown in FIG. 1B, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated video coding, or any combinations thereof. Encoder 20 may be implemented via processing circuitry 46 to implement various modules, as discussed with respect to encoder 20 of FIG. 2 and/or any other encoder system or subsystem described herein. Decoder 30 may be implemented via processing circuitry 46 to implement various modules, as discussed in relation to decoder 30 of FIG. 3 and/or any other decoder system or subsystem described herein. The processing circuit may be configured to perform various operations, which will be described below. As shown in FIG. 5, if the techniques are partially implemented in software, a device may store instructions for the software on a suitable, durable, computer-readable storage medium and may execute instructions in hardware using one or more processors to execute the techniques of this disclosure. Either of video encoder 20 and video decoder 30 may be integrated as part of a combined coder/decoder (CODEC) in a single device, such as shown in FIG. 1b.

Source device 12 and destination device 14 may comprise any of a wide range of devices, including any type of portable or stationary device, such as laptops or laptops, mobile phones, smartphones, tablets or tablet computers, cameras, desktop computers, set-top boxes. , televisions, display devices, digital media players, game consoles, video streaming devices (for example, content service servers or content delivery servers), broadcast receiver, broadcast transmitter or the like, and may use any type of operating system or do without it. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices.

In some cases, the video coding system 10 illustrated in FIG. 1A is only an example, and the methods of the present application may be applied to video encoding settings (such as video encoding or video decoding) that do not necessarily involve any data transfer between encoding and decoding devices. In other examples, data is retrieved from local memory, streamed over a network, or the like. The video encoder may encode and store data in the memory, and/or the video decoder may retrieve and decode data from the memory. In some examples, encoding and decoding is performed by devices that do not communicate with each other, but simply encode data into memory and/or retrieve and decode data from memory.

For convenience of description, embodiments of the present invention are described herein, for example, with reference to High Efficiency Video Coding (HEVC) or Universal Video Coding (VVC) reference software, the next generation video coding standard being developed by the Joint Video Coding Collaborative (JCT-VC) Expert Group on ITU-T Video Coding (VCEG) and the ISO/IEC Moving Picture Expert Group (MPEG). One of ordinary skill in the art will appreciate that the embodiments of the present invention are not limited to HEVC or VVC.

Encoder and encoding method

FIG. 2 shows a schematic block representation of an exemplary video encoder 20 that is capable of implementing the methods of the present application. In the example in FIG. 2, video encoder 20 includes an input 201 (or input interface 201), a residual calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block 210, and an inverse transform processing block 212, a reconstruction block 214, a loop filter block 220, a buffer 230 ( DPB) of decoded pictures, mode selection block 260, entropy encoding block 270, and output 272 (or output interface 272). The mode selector 260 may include an inter-predictor 244, an intra-predictor 254, and a splitter 262. Inter prediction block 244 may include a motion estimator and a motion compensation block (not shown). Video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.

The residual calculation block 204, the transform processing block 206, the quantization block 208, the mode selection block 260 may relate to the formation of the forward signal path of the encoder 20, while the inverse quantization block 210, the inverse transform processing block 212, the recovery block 214, the buffer 216, the contour filter 220, decoded picture buffer (DPB) 230, inter-prediction 244, and intra-prediction 254 may be related to generating a reverse signal path of video encoder 20, wherein the reverse signal path of video encoder 20 corresponds to the signal path of a decoder (see video decoder 30 in Fig. 3). An inverse quantization block 210, an inverse transform processing block 212, a reconstruction block 214, a loop filter 220, a decoded picture buffer (DPB) 230, an inter-prediction block 244, and an intra-prediction block 254 are also related to the formation of the "embedded decoder" of the video encoder 20.

Images and Image Sharing (Images and Blocks)

Encoder 20 may be configured to receive, for example, via input 201, an image 17 (or image data 17), such as an image from a sequence of images constituting a video or a video sequence. The received image or image data may also be a pre-processed image 19 (or pre-processed image data 19). For simplicity, the following description refers to picture 17. Picture 17 may also be referred to as the current picture or the picture to be encoded (particularly in video encoding, to distinguish the current picture from other pictures, such as previously encoded and/or decoded pictures of the same video sequence, i.e. a video sequence that also contains the current image).

A (digital) image is, or can be viewed as, a two-dimensional array or matrix of samples with intensity values. A sample in an array can also be referred to as a pixel (short form of picture element) or pel (picture element). The number of samples in the horizontal and vertical direction (or axis) of the array or image determines the size and/or resolution of the image. Three color components are commonly used to represent a color, i.e. the image may be represented by or include three arrays of samples. In RBG format or color space, an image contains a corresponding array of red, green, or blue samples. However, in video coding, each pixel is typically represented in a luma and chrominance format or color space, such as YCbCr, which contains a luminance component, denoted Y (sometimes L is also used instead), and two chrominance components (chroma components), denoted Cb and Cr. The Y component of luminance (or luma for short) represents the brightness (brightness) or gray level intensity (for example, as in a grayscale image), while the two components Cb and Cr are chrominance (or chrominance for short ( chroma)) represent components of chromaticity or color information. Accordingly, a YCbCr image contains an array of luma samples with luminance sample values (Y) and two arrays of chrominance samples with chrominance values (Cb and Cr). Images in RGB format can be converted or converted to YCbCr format and vice versa, the process is also known as color conversion or conversion. If the image is monochrome, it can only contain an array of brightness samples. Accordingly, the image may be, for example, an array of luminance samples in monochrome format, or an array of luminance samples and two corresponding arrays of chrominance samples in 4:2:0, 4:2:2 and 4:4:4 color format.

Embodiments of video encoder 20 may comprise an image splitter (not shown in FIG. 2) configured to split image 17 into multiple (generally non-overlapping) image blocks 203. These blocks may also be referred to as root blocks, macroblocks (H.264/AVC), or coding tree blocks (CTBs) or coding tree units (CTUs) (H.265/HEVC and VVC). The image dividing block may be configured to use the same block size for all images in a video sequence and a corresponding grid defining the block size, or to change the block size between images or subsets or groups of images and divide each image into appropriate blocks.

In further embodiments, the video encoder may be configured to directly receive image block 203 17, such as one, more or all of the blocks forming image 17. Image block 203 may also be referred to as the current image block or image block to be encoded.

Like image 17, image block 203 is again, or can be viewed as, a two-dimensional array or matrix of samples with intensity values (sample values), albeit smaller than image 17. In other words, block 203 may contain, for example, one array of samples (for example , a luma array in the case of a monochrome image 17, or an array of luminance or chrominance in the case of a color image) or three arrays of samples (for example, luminance and two chrominance arrays in the case of a color image 17) or any other number and/or type of arrays depending on the applied color format. The number of samples in the horizontal and vertical direction (or axis) of block 203 determines the size of block 203. Accordingly, the block may, for example, be an MxN (M-column per N-row) array of samples or an MxN array of transform coefficients.

The embodiments of video encoder 20 shown in FIG. 2 may be configured to encode picture 17 block by block, such as encoding and prediction is performed for each block 203.

Embodiments of video encoder 20, as shown in FIG. 2 may be further configured to split and/or encode an image using slices (also referred to as video slices), wherein the image may be split into or encoded using one or more slices (generally non-overlapping), and each slice may contain one or more units (eg CTU).

The embodiments of video encoder 20 shown in FIG. 2 may be further configured to split and/or encode an image using groups of tiles (also referred to as video tiles) and/or tiles (also referred to as video tiles), wherein the image may be divided into or encoded with using one or more tile groups (generally non-overlapping), and each tile group may contain, for example, one or more blocks (eg, CTUs) or one or more tiles, each tile, by way of example, may have rectangular in shape and may contain one or more blocks (eg, CTU), such as full or partial blocks.

Remainder Calculation

Residual block 204 can be configured to calculate residual block 205 (also referred to as residual 205) based on image block 203 and prediction block 265 (more details on predictor 265 are provided below), for example, by subtracting the sample values of predictor 265 from the values samples of the image block 203, sample by sample (pixel by pixel), to obtain a residual block 205 in the sample area.

transformation

The transform processing unit 206 may be configured to apply a transform, such as a discrete cosine transform (DCT) or a discrete sine transform (DST), to the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. Transform coefficients 207 may also be referred to as residual transform coefficients and represent a residual block 205 in the transform region.

Transform processing unit 206 may be configured to apply DCT/DST integer approximations such as those defined for H.265/HEVC. Compared to the orthogonal DCT, such integer approximations are usually scaled by a certain factor. To preserve the norm of the residual block that is processed by forward and backward transforms, additional scaling factors are applied as part of the transform process. The scaling factors are usually chosen based on certain constraints, for example the scaling factors are a power of two for shift operations, the bit depth of the transform coefficients, the trade-off between precision and implementation cost, etc. Specific scaling factors, for example, are specified for the inverse transform, for example 212 inverse transform processing (and corresponding inverse transform, such as by inverse transform processor 312 in video decoder 30), and corresponding scaling factors for direct transform, such as by transform processor 206, may be appropriately set in encoder 20.

Embodiments of video encoder 20 (respectively, transform processing unit 206) may be configured to output transform parameters, such as the type of transform or transforms, such as directly or encoded or compressed via entropy encoding unit 270, so that, for example, video decoder 30 may receive and use transformation parameters for decoding.

Quantization

Quantizer 208 may be configured to quantize transform coefficients 207 to obtain quantized coefficients 209, for example by applying scalar quantization or vector quantization. The quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207 . For example, an n-bit transform factor may be rounded to an m-bit transform factor during quantization, where n is greater than m. The degree of quantization can be changed by adjusting the quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. The applicable quantization step size may be indicated by a quantization parameter (QP). The quantization parameter may, for example, be an index to a predefined set of applicable quantization step sizes. For example, small quantization parameters may correspond to fine quantization (small quantization step sizes), and large quantization parameters may correspond to coarse quantization (large quantization step sizes), or vice versa. Quantization may include dividing by the quantization step size, and corresponding and/or inverse dequantization, for example by inverse quantizer 210, may include multiplying by the quantization step size. Embodiments in accordance with some standards, such as HEVC, may be configured to use a quantization parameter to determine the quantization step size. Typically, the quantization step size can be calculated based on the quantization parameter using a fixed-point approximation of an equation involving division. Additional scaling factors may be introduced for quantization and dequantization to recover the residual block rate that may have changed due to the scaling used in the fixed point approximation of said equation for quantization step size and quantization parameter. In one exemplary implementation, inverse transform scaling and dequantization may be combined. Alternatively, customized quantization tables may be used and signaled from encoder to decoder, eg in a bitstream. Quantization is a lossy operation in which the loss increases as the size of the quantization steps increases.

Embodiments of video encoder 20 (respectively quantizer 208) may be configured to output quantization parameters (QPs), for example directly or encoded via entropy coding unit 270, so that, for example, video decoder 30 may receive and use these quantization parameters for decoding.

Inverse quantization

The inverse quantizer 210 is configured to apply the inverse quantization of the quantizer 208 to the quantized coefficients to obtain the dequantized coefficients 211, for example by applying an inverse quantization scheme to that applied by the quantizer 208 based on or using the same quantization step size as the block 208 quantization. The dequantized coefficients 211 may also be referred to as the dequantized residual coefficients 211 and correspond - although they are usually not identical to the transform coefficients due to quantization loss - to the transform coefficients 207 .

Reverse transformation

The inverse transform processor 212 is configured to apply an inverse transform with respect to the transform applied by the transform processor 206, such as an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transforms, to obtain a reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample area. The recovered residual block 213 may also be referred to as a transform (recovered) block 213 .

Recovery

Reconstructor 214 (eg, adder or adder 214) is configured to add the (recovered) transform block 213 (i.e., reconstructed residual block 213) to prediction block 265 to obtain reconstructed block 215 in the sample domain, such as by adding - sample by sample - sample values of the reconstructed residual block 213 and sample values of the prediction block 265 .

Filtration

The loop filter block 220 (or "loop filter" 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or more generally to filter the reconstructed samples to obtain filtered samples. The loop filter unit, for example, is configured to smooth out pixel transitions or otherwise improve video quality. The loop filter block 220 may comprise one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, such as a two-sided filter, an adaptive loop filter (ALF), anti-aliasing, enhancement filters. sharpening or joint filters, or any combination of them. Although the loop filter unit 220 is shown in FIG. 2 as an in-loop filter, in other configurations, the loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as the filtered reconstructed block 221.

Embodiments of video encoder 20 (respectively, loop filter unit 220) may be configured to output loop filter parameters (such as sample-adaptive offset information), for example, directly or encoded through entropy encoding unit 270, so that, for example, decoder 30 may receive and apply similar loop filter parameters or appropriate loop filters for decoding.

Decoded picture buffer

Decoded Picture Buffer (DPB) 230 may be a memory that stores reference pictures or, more generally, reference picture data for encoding video data by video encoder 20. DPB 230 may be formed by any of a variety of memories such as dynamic random access memory ( DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may be further configured to store other previously filtered blocks, such as previously reconstructed and filtered blocks 221, the same current picture, or different images, such as previously restored images, and can provide complete previously restored, i.e. decoded, pictures (and corresponding reference blocks and samples) and/or partially reconstructed current picture (and corresponding reference blocks and samples), for example, for inter-prediction. The decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or more generally unfiltered reconstructed samples, such as if the reconstructed block 215 is not filtered by the loop filter block 220, or any other further processed version of the reconstructed blocks. or samples.

Mode selection (separation and prediction)

The mode selector 260 includes a splitter 262, an inter-prediction 244, and an intra-prediction 254, and is configured to receive or obtain original image data such as the original block 203 (the current block 203 of the current image 17) and reconstructed image data, such as filtered and/or unfiltered reconstructed samples or blocks of the same (current) picture and/or from one or a plurality of previously decoded pictures, such as decoded picture buffer 230 or other buffers (such as a linear (string) buffer, not shown). The reconstructed image data is used as reference image data for prediction, such as inter-prediction or intra-prediction, to obtain prediction block 265 or predictor 265.

The mode selector 260 may be configured to determine or select a split for the current block prediction mode (including no split) and prediction mode (e.g., intra- or inter-prediction mode) and generate a corresponding prediction block 265 that is used to calculate the residual block 205 and to restore the restored block 215.

Embodiments of mode selector 260 may be configured to select a split and prediction mode (e.g., those supported by or available to mode selector 260) that provide the best match, or in other words, minimum residual (minimum residual means best compression for transmission or storage), or minimal signaling overhead (lowest signaling overhead means better compression for transmission or storage), or which considers or balances both. The mode selector 260 may be configured to determine a splitting and prediction mode based on rate/distortion optimization (RDO), ie, selecting a prediction mode that provides minimal distortion at a certain rate. Terms such as "best", "minimum", "optimal", etc. in this context do not necessarily refer to the all-inclusive "best", "minimum", "optimal", etc., but may also refer to meeting a selection or termination criterion, such as when a value exceeds or falls below a threshold value, or other constraints potentially leading to a "sub-optimal selection" but reducing complexity and processing time.

In other words, partitioner 262 may be configured to partition block 203 into smaller block partitions or subblocks (which again form blocks), such as iteratively using quadtree partitioning (QT), binary partitioning (BT), or ternary tree partitioning (TT). ) or any combination thereof, and performing, for example, prediction for each of the block partitions or subblocks, wherein the mode selection comprises selecting a tree structure of the shared block 203, and the prediction modes are applied to each of the block partitions or subblocks.

The following explains in more detail the division (for example, by the division block 260) and the prediction processing (by the inter prediction block 244 and the intra prediction block 254) performed by the exemplary video encoder 20.

Separation

Partitioner 262 may divide (or split) the current block 203 into smaller sections, such as smaller square or rectangular sized blocks. These smaller blocks (which may also be referred to as sub-blocks) may be further subdivided into even smaller sections. This is also called tree splitting or hierarchical tree splitting, in which a root box, such as at root level 0 of the tree (hierarchy level 0, depth 0), can be split recursively, such as split into two or more boxes of the next lower level of the tree, such as nodes at level 1 of the tree (hierarchy level 1, depth 1), whereby these blocks can be split again into two or more blocks at the next lower level, e.g. tree level 2 (hierarchy level 2, depth 2), etc. until the split will not complete, for example, because a termination criterion is met, such as reaching the maximum tree depth or minimum block size. Blocks that are not further separated are also called leaf blocks or leaf nodes of the tree. A tree using two partitions is called a binary tree (BT), a tree using three partitions is called a ternary tree (TT), and a tree using four partitions is called a quadtree (QT).

As mentioned earlier, the term "block" as used herein can be a part, in particular a square or rectangular part of an image. With regard to, for example, HEVC and VVC, a block can be either a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transformation unit (TU) and/or corresponding blocks, such as a coding tree block (CTB). ), a coding block (CB), a transformation block (TB), or a prediction block (PB).

For example, a coding tree unit (CTU) may be either a luminance sample CTB, two corresponding chrominance sample CTBs of an image that has three sample arrays, or a monochrome image sample CTB or an image that is encoded using three separate color planes and the syntax structures used to encode samples. Accordingly, a coding tree block (CTB) may be an N×N block of samples for some value of N, such that dividing a component by a CTB is a split. A coding unit (CU) can be either a luminance sample coding unit, two corresponding chrominance sample coding units of an image that has three sample arrays, or a monochrome image sample coding unit or an image that is encoded using three separate color planes and the syntax structures used to encode samples. Accordingly, a coding block (CB) may be an M×N block of samples for some values of M and N, so dividing the CTB into coding blocks is a division.

In embodiments, for example, according to HEVC, a coding tree unit (CTU) may be partitioned into CUs using a quadtree structure designated as a coding tree. The decision whether to encode an image area using inter-picture (temporal) or intra-picture (spatial) prediction is made at the CU layer. Each CU may be further partitioned into one, two or four PUs according to the type of PU partitioning. Within one PU, the same prediction process is applied, and the relevant information is transmitted to the decoder based on the PU. After obtaining the residual block by applying the prediction process based on the partition type to the PU, the CU can be divided into transform units (TU) according to a different quadtree structure similar to the coding tree for the CU.

In embodiments, for example, in accordance with the newest video coding standard currently being developed, called universal video coding (VVC), eg, combined quadtree-binary tree (QTBT) splitting is used to split a coding block. In the block structure of the QTBT, the CU can be either square or rectangular. For example, a coding tree unit (CTU) is first divided into a quadtree structure. The leaf nodes of the quadtree are further separated by a binary tree or a ternary (or ternary) tree structure. The leaf nodes of the partitioning tree are called coding units (CUs) and this segmentation is used for prediction and transformation processing without any further partitioning. This means that CU, PU and TU have the same block size in the QTBT coding block structure. In parallel, a multiple partition, such as a ternary tree partition, can be used in conjunction with the QTBT box structure.

In one example, mode selector 260 of video encoder 20 may be configured to perform any combination of the separation techniques described herein.

As described above, video encoder 20 is configured to determine or select the best or optimal prediction mode from a set of (eg, predefined) prediction modes. The set of prediction modes may include, for example, intra-prediction modes and/or inter-prediction modes.

Intra prediction

The set of intra prediction modes may contain 35 different intra prediction modes, such as non-directional modes such as DC (or average) mode and planar mode, or directional modes such as those defined in HEVC, or may contain 67 different intra prediction modes , for example, non-directional modes, such as DC (or average) mode and planar mode, or directional modes, for example, as defined in VVC.

The intra prediction block 254 is configured to use the recovered samples of neighboring blocks of the same current image to generate the intra prediction block 265 according to the intra prediction mode of the intra prediction mode set.

The intra-prediction block 254 (or mode selection block 260 more generally) is further configured to output the intra-prediction parameters (or, more generally, information indicative of the selected intra-prediction mode for the block) to the entropy encoding block 270 in the form of syntactic elements 266 to be included in the encoded image data 21 so that, for example, video decoder 30 can receive and use prediction parameters for decoding.

Inter prediction

The set of (possible) inter-prediction modes depends on the available reference pictures (i.e. previous at least partially decoded pictures, e.g. stored in DBP 230) and other inter-prediction parameters, e.g. search windows around the area of the current block, a reference image to find the most suitable reference block, and/or, for example, whether pixel interpolation is applied, such as half-pixel (half/semi-pel) and/or quarter-pel interpolation, or not.

In addition to the aforementioned prediction modes, a skip mode and/or a direct mode may be applied.

Inter prediction block 244 may include a motion estimator (ME) and a motion compensation (MC) block (both not shown in FIG. 2). The motion estimator may be configured to receive or obtain an image block 203 (the current image block 203 of the current image 17) and a decoded image 231, or at least one or a plurality of previously reconstructed blocks, such as reconstructed blocks of one or a plurality of other/different previously decoded 231 images for motion estimation. For example, the video sequence may comprise the current picture and previously decoded pictures 231 or, in other words, the current picture and previously decoded pictures 231 may be part of or form a sequence of pictures that make up the video sequence.

Encoder 20 may, for example, be configured to select a reference block from a plurality of reference blocks of the same or different pictures from a plurality of other pictures and provide a reference picture (or reference picture index) and/or offset (spatial offset) between position (x, y coordinates ) of the reference block and the position of the current block as inter-prediction parameters to the motion estimation block. This offset is also called motion vector (MV).

The motion compensation block is configured to obtain, for example, receive an inter prediction parameter and perform inter prediction based on or using the inter prediction parameter to obtain inter prediction block 265 . The motion compensation performed by the motion compensator may include deriving or generating a prediction block based on the motion vector/block determined by the motion estimation, possibly performing sub-pixel-accurate interpolations. Interpolation filtering can generate additional pixel samples from known pixel samples, thus potentially increasing the number of candidate prediction blocks that can be used to encode an image block. After receiving the motion vector for the PU of the current picture block, the motion compensator may locate the prediction block pointed to by the motion vector in one of the reference picture lists.

The motion compensation block may also generate syntax elements associated with video blocks and slices for use by video decoder 30 when decoding image blocks of a video slice. In addition to or as an alternative to slices and corresponding syntax elements, groups of tiles and/or tiles and corresponding syntax elements can be generated or used.

Entropy coding

Entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or scheme (for example, variable length coding (VLC) scheme, context adaptive VLC (CAVLC) scheme, arithmetic coding scheme, binarization, context adaptive binary arithmetic coding ( CABAC) based on the syntax of context adaptive binary arithmetic coding (SBAC), probability interval division entropy coding (PIPE), or other entropy coding method or methodology) or traversal (no compression) in relation to quantized coefficients 209, inter-prediction parameters, intra-prediction parameters, loop filter parameters, and/or other syntax elements for obtaining encoded image data 21 that can be output via output 272, such as in the form of an encoded bitstream 21, so that, for example, video decoder 30 can receive and use these parameters to decoding niya, . The encoded bitstream 21 may be transmitted to video decoder 30 or stored in memory for later transmission or retrieval by video decoder 30.

Other changes to the structure of video encoder 20 may be used to encode the video stream. For example, non-transform-based encoder 20 may quantize the residual signal directly without transform processing unit 206 for certain blocks or frames. In another implementation, the encoder 20 may have a quantizer 208 and an inverse quantizer 210 combined into a single block.

Decoder and decoding method

FIG. 3 shows an example of a video decoder 30 that is configured to implement the methods of the present application. Video decoder 30 is configured to receive encoded image data 21 (e.g., encoded bitstream 21), such as encoded by encoder 20, to obtain a decoded image 331. The encoded image data or bitstream contains information for decoding encoded image data, such as data that represents blocks encoded video slice images (and/or tiles or groups of tiles) and associated syntax elements.

In the example in FIG. 3, the decoder 30 includes an entropy decoding block 304, an inverse quantization block 310, an inverse transform processing block 312, a reconstruction block 314 (e.g., an adder 314), a loop filter 320, a decoded picture buffer (DPB) 330, a mode application block 360, a block 344 inter-predictions and block 354 intra-predictions. Inter prediction block 344 may be or include a motion compensation block. Video decoder 30 may, in some examples, perform a decoding pass generally reverse of the encoding pass described with respect to video encoder 100 in FIG. 2.

As described with respect to encoder 20, inverse quantization block 210, inverse transform processing block 212, reconstruction block 214, loop filter 220, decoded picture buffer (DPB) 230, inter-prediction block 344, and intra-prediction block 354 are also related to generating an "embedded decoder" of the video encoder 20. Accordingly, the inverse quantization block 310 may be identical in function to the inverse quantization block 110, the inverse transform processing block 312 may be identical in function to the inverse transform processing block 212, the reconstruction block 314 may be identical in function to the reconstruction block 214, contour filter 320 may be identical in function to loop filter 220, and decoded picture buffer 330 may be identical in function to decoded picture buffer 230. Therefore, the explanations provided for the respective blocks and functions of the video encoder 20 apply, respectively, to the corresponding blocks and functions of the video decoder 30.

Entropy decoding

The entropy decoding unit 304 is configured to parse the bitstream 21 (or encoded image data 21 in general) and perform, for example, entropy decoding of the encoded image data 21 to obtain, for example, quantized coefficients 309 and/or decoded coding parameters ( not shown in Fig. 3), such as any or all of the inter-prediction parameters (eg, reference picture index and motion vector), intra-prediction parameter (eg, index or intra-prediction mode), transform parameters, quantization parameters, loop filter parameters and/or other syntax elements. Entropy decoding unit 304 may be configured to apply decoding algorithms or schemes corresponding to coding schemes as described in relation to entropy encoding unit 270 of encoder 20. Entropy decoding unit 304 may be further configured to provide inter-prediction parameters, intra-prediction parameter and/or other syntax elements to the mode application block 360 and other parameters to other blocks of the decoder 30. Video decoder 30 may receive syntax elements at the video slice level and/or the video block level. In addition to or as an alternative to slices and corresponding syntax elements, groups of tiles and/or tiles and corresponding syntax elements may be accepted and/or used.

Inverse quantization

The inverse quantizer 310 may be configured to receive quantization parameters (QPs) (or inverse quantization related information in general) and quantized coefficients from the encoded image data 21 (e.g., by parsing and/or decoding, e.g., by entropy decoding block 304) and applying, based on the quantization parameters, inverse quantization to the decoded quantized coefficients 309 to obtain dequantized coefficients 311, which may also be referred to as transform coefficients 311. The inverse quantization process may include using a quantization parameter determined by video encoder 20 for each video block in a video slice (or tile or group of tiles) to determine the amount of quantization and, likewise, the amount of inverse quantization to be applied.

Reverse transformation

The inverse transform processor 312 may be configured to receive the dequantized coefficients 311, also referred to as transform coefficients 311, and apply a transform to the dequantized coefficients 311 in order to obtain reconstructed residual blocks 213 in the sample domain. The recovered residual blocks 213 may also be referred to as transform blocks 213 . The transformation may be an inverse transformation, eg, inverse DCT, inverse DST, inverse integer transformation, or a conceptually similar inverse transformation process. The inverse transform processing unit 312 may be further configured to receive transformation parameters or corresponding information from the encoded image data 21 (eg, by parsing and/or decoding, eg, by entropy decoding unit 304) to determine the transformation to be applied to dequantized coefficients 311.

Recovery

A reconstructor 314 (e.g., adder or adder 314) is configured to add the reconstructed transform block 313 to the predictor 365 to obtain a reconstructed block 315 in the sample region, such as by adding the sample values of the reconstructed residual block 313 and the sample values of the predictor 365.

Filtration

The loop filter block 320 (either in the encoding loop or after the encoding loop) is configured to filter the reconstructed block 315 to obtain a filtered block 321, for example, to smooth pixel transitions or otherwise improve video quality. The loop filter block 320 may comprise one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or one or more other filters, such as a two-sided filter, an adaptive loop filter (ALF), anti-aliasing, enhancement filters. sharpening or joint filters, or any combination of them. Although the loop filter unit 320 is shown in FIG. 3 as an in-loop filter, in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

Decoded picture buffer

The decoded video blocks 321 of the picture are then stored in the decoded picture buffer 330, which stores the decoded pictures 331 as reference pictures for subsequent motion compensation for other pictures and/or for display output, respectively.

The decoder 30 is configured to output the decoded image 311, for example, via output 312 for presentation or viewing by a user.

Prediction

The inter-prediction block 344 may be identical to the inter-prediction block 244 (in particular, the motion compensation block), and the intra-prediction block 354 may be identical to the function inter-prediction block 254, and makes split or split decisions and performs prediction on based on the separation and/or prediction parameters or corresponding information received from the encoded image data 21 (for example, by parsing and/or decoding, for example, by entropy decoding block 304). Mode apply block 360 may be configured to perform prediction (intra- or inter-prediction) for each block based on reconstructed images, blocks, or corresponding samples (filtered or unfiltered) to obtain prediction block 365 .

When a video slice is encoded as an intra-coded (I) slice, the intra-prediction block 354 of the mode apply block 360 is configured to generate a prediction block 365 for the image block of the current video slice based on the signaled intra-prediction mode and data from previously decoded blocks of the current image. When a video image is encoded as an inter-coded (i.e., B or P) slice, the inter-prediction block 344 (eg, motion compensation block) of the mode apply block 360 is configured to create prediction blocks 365 for the video block of the current video slice based on the motion vectors and other syntax elements received from block 304 entropy decoding. For inter-prediction, prediction blocks may be created from one of the reference pictures within one of the reference picture lists. Video decoder 30 may construct the key frame lists, List 0 and List 1 using default construction methods based on the reference pictures stored in the DPB 330. The same or similar may apply to or through embodiments using groups of tiles (e.g., groups video tiles) and/or tiles (eg, video tiles) in addition to or alternatively to slices (eg, video slices), for example, video may be encoded using groups I, P, or B of tiles and/or tiles.

The mode applyer 360 is configured to determine prediction information for a video block of the current video slice by parsing motion vectors or related information and other syntax elements, and uses the prediction information to create prediction blocks for the current video block being decoded. For example, the mode applicator 360 uses some of the received syntax elements to determine the prediction mode (eg, intra- or inter-prediction) used to encode the video blocks of the video slice, the type of inter-prediction slice (eg, B-slice, P-slice, or GPB -slice), construction information for one or more reference picture lists for the slice, motion vectors for each inter-coded video block of the slice, inter-prediction status for each inter-coded video block of the slice, and other information for decoding video blocks in the current video slice. The same or similar may apply to or through embodiments using groups of tiles (e.g., groups of video tiles) and/or tiles (e.g., groups of video tiles) in addition to or alternatively to slices (e.g., video slices), e.g. , the video may be encoded using groups I, P, or B of tiles and/or tiles.

Embodiments of video decoder 30, as shown in FIG. 3 may be configured to split and/or decode an image using slices (also referred to as video slices), wherein the image may be split into or decoded using one or more slices (generally non-overlapping), and each slice may contain one or more blocks (for example, CTU).

Embodiments of video decoder 30 shown in FIG. 3 may be configured to split and/or decode an image using tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles), wherein the image may be divided into or decoded using one or more tile groups (generally non-overlapping), and each tile group may contain, for example, one or more blocks (eg, CTUs) or one or more tiles, each tile, by way of example, may have a rectangular form and may contain one or more blocks (eg, CTUs), such as full or partial blocks.

Other versions of the video decoder 30 may be used to decode the encoded image data 21 . For example, the decoder 30 may produce an output video stream without the loop filter block 320 . For example, non-transform-based decoder 30 may inversely quantize the residual signal directly without inverse transform processing unit 312 for certain blocks or frames. In another implementation, video decoder 30 may have an inverse quantizer 310 and an inverse transform processor 312 combined into a single unit.

It should be understood that in encoder 20 and decoder 30, the processing result of some current stage may be further processed and then output to the next stage. For example, after interpolation filtering, motion vector acquisition, or contour filtering, an additional operation such as Clip (truncation) or offset may be performed on the result of the interpolation filtering, motion vector acquisition, or contour filtering processing.

It should be noted that additional operations may be applied to the resulting motion vectors of the current block (including, but not limited to, affine mode checkpoint motion vectors, sub-block motion vectors in affine, planar, ATMVP modes, temporal motion vectors, and the like). For example, the motion vector value is limited to a predefined range according to its representing bit. If the representing bit of the motion vector is bitDepth (bit depth), then the range is -2^(bitDepth-1) ~ 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is 16, the range is -32768~32767; if bitDepth is 18, the range is -131072~131071. For example, the value of the resulting motion vector (e.g., MV of four 4x4 subblocks in one 8x8 block) is limited so that the maximum difference between integer parts of the MVs of four 4x4 subblocks does not exceed N pixels, for example, is no more than 1 pixel. Here are two ways to limit the motion vector according to bitDepth.

FIG. 4 is a schematic representation of a video encoding apparatus 400 according to an embodiment of the present disclosure. The video encoder 400 is suitable for implementing the disclosed embodiments that are described herein. In an embodiment, video encoding device 400 may be a decoder, such as video decoder 30 of FIG. 1A or an encoder such as video encoder 20 of FIG. 1A.

The video encoder 400 includes input ports 410 (or input ports 410) and receiver units (Rx) 420 for receiving data; a processor, logical unit, or central processing unit (CPU) 430 for processing data; blocks 440 (Tx) transmitter and output ports 450 (or ports 450 output) for data transmission; and a memory 460 for storing data. The video encoder 400 may also include optical-to-electrical (OE) and electrical-to-optical (EO) components connected to input ports 410, receiver units 420, transmitter units 440, and output ports 450 to provide input or output of optical or electrical signals.

Processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (eg, as a multi-core processor), FPGA, ASIC, and DSP. The processor 430 communicates with input ports 410, receiver units 420, transmitter units 440, output ports 450, and memory 460. Processor 430 includes an encoding module 470. Encoding module 470 implements the disclosed embodiments described above. For example, encoding module 470 implements, processes, prepares, or provides various encoding operations. Therefore, the inclusion of the encoding module 470 provides a significant improvement in the functionality of the video encoding device 400 and allows the transformation of the video encoding device 400 to another state. Alternatively, encoding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

Memory 460 may comprise one or more disks, tape drives, and solid state drives, and may be used as an overflow storage device for storing programs when such programs are selected for execution, and for storing instructions and data that are read during program execution. Memory 460 may be, for example, volatile and/or non-volatile and may be Read Only Memory (ROM), Random Access Memory (RAM), Ternary Associative Memory (TCAM), and/or Static Random Access Memory (SRAM).

FIG. 5 is a simplified block diagram of a device 500 that can be used as one or both of source device 12 and sink device 14 of FIG. 1 according to an exemplary embodiment.

Processor 502 in device 500 may be a central processing unit. Alternatively, processor 502 may be any other type of device or a plurality of devices capable of manipulating or processing information that currently exists or will be developed in the future. Although the disclosed implementations may be practiced with a single processor, as shown with processor 502, for example, speed and efficiency advantages may be achieved using more than one processor.

The memory 504 in the device 500 may be a read only memory (ROM) or a random access memory (RAM) device in an implementation. Memory 504 may be any other suitable type of storage device. Memory 504 may include code and data 506 accessed by processor 502 using bus 512. Memory 504 may further include an operating system 508 and application programs 510, application programs 510 including at least one program, which allows the processor 502 to perform the methods described herein. For example, application programs 510 may include applications 1 through N, which further include a video encoding application that performs the methods described herein.

The device 500 may also include one or more output devices, such as a display 518. The display 518 may be, in one example, a touch display that combines a display with a touch element that is capable of receiving touch inputs (by touch). Display 518 may be coupled to processor 502 via bus 512.

Although shown here as a single bus, bus 512 of device 500 may be composed of multiple buses. In addition, secondary storage 514 may be directly connected to other components of the device 500 or may be accessed via a network and may contain a single pluggable unit, such as a memory card, or multiple units, such as a plurality of memory cards. Thus, device 500 can be implemented in a wide variety of configurations.

The intra-subsection (ISP) coding tool divides the intra-block (predictions) into a plurality of subsections and predicts these subsections, for example, first predicts one subsection and then predicts the next subsection. In some situations, there may be discontinuities at the boundaries of subsections, causing blocking artifacts.

In one example, Figure 6 shows the ISP division of the intra-block 600 into multiple subsections. In this example, there are two directional sections, a horizontal section 601 and a vertical section 602; in other examples (not shown in FIG. 6) another split is performed, such as an angled directional split. In the example shown in FIG. 6, subsections and corresponding boundaries are labeled with vertical partition 602. Here, intra-block 600 is divided into four subsections, namely sub0, sub1, sub2, and sub3. Three subdivision boundaries are labeled, namely: subdivision boundary A between subdivision 0 and 1, subdivision boundary B between subdivision 1 and 2, subdivision boundary C between subdivision 2 and 3, a similar definition can be used in the horizontal partition example 601.

In one embodiment, subsection prediction is performed by the ISP tool, subsections may be decoded sequentially. For one sub-subsection, the residual signal may be generated by entropy decoding the coefficients sent by the encoder and then dequantizing and inverse transforming them. The subsection is then intra-predicted and finally the corresponding reconstructed samples are obtained by adding the residual signal to the prediction signal. The prediction signal may mainly represent an intra-prediction that is performed based on the angular mode with respect to the rows of the top and left reference samples. The remainder is decoded and then added to the prediction signal to form the final prediction. These recovered samples are then used to predict the next subsection. Therefore, the recovered values of one subsection will be available to generate a prediction of the next subsection, which is a repetition of the process, and so on. All subsections (sub0, sub1, sub2, sub3) use the same intra mode.

Generally, two processing orders can be used for subsections: normal order and reverse order. In the example, for a horizontal section, the normal order is from top to bottom, and the reverse order is from bottom to top. In another example, for vertical partitions, the normal order is from left to right, and the reverse order is from right to left.

As shown in FIG. 7, to reduce blocking artifacts caused by the ISP encoding tool, subsection boundaries within an ISP-applied block are subjected to deblocking filtering after codingblock 700 is horizontally subdivided into subsections 701 or after codingblock 700 is vertically subdivided into subsections 702. Several alternative methods are proposed for applying deblocking filters on those subsection boundaries.

Deblocking filtering with increased border intensity.

Edge intensity (Bs) is a parameter that is used to control the strength of the deblocking filtering. The higher the value of Bs, the more samples perpendicular to the boundary can be filtered out. The ISP prediction may lead to an error propagation problem, namely, the prediction error propagates with the processing order.

In one example, as shown in Figure 6, with vertical splitting and normal coding block (coding unit) processing order, the samples in these subsections are reconstructed from left to right, namely sub0, sub1, sub2, and sub3. Subsection 0 may generally have better prediction quality since its reference samples (from the left neighbor block and the top neighbor block) have already been reconstructed. However, the left side of the subsection 1 reference samples is derived from the reconstructed subsection 0, so the subsection 1 reference samples may not be as accurate as those of subsection 0, resulting in a larger residual signal. Similarly, the subsection 2 reference samples are even worse than those of subsection 1, and the prediction error propagates along with the processing order.

A method is proposed to increase the intensity of the border with the order of processing. Namely, when the boundary between two subsections (eg, boundary A, B, C in Fig. 6) is closer to adjacent blocks, then Bs for that boundary is set to a smaller value because that boundary has a smaller error. When the boundary is further away from adjacent blocks, then Bs for that boundary is set to a higher value, since the boundary has a larger error due to error propagation.

In one example, as shown in Figure 6, with a vertical partition and normal (left to right) processing order performed on a block, Bs of subsection boundary A is set to 0, Bs of subsection boundary B is set to 1, Bs of subsection boundary C is set to 2.

In one example, as shown in Figure 6, with a vertical partition and reverse (right to left) processing order performed on a block, Bs of subsection boundary A is set to 2, Bs of subsection boundary B is set to 1, Bs of subsection boundary C is set to 0.

In another example, a similar process is performed for horizontal sections.

Deblocking filtering based on Coded Block Flag (CBF).

In the example, each subsection is predicted and reconstructed separately, each subsection may have different residual information (the difference between the original signal and the predicted signal). In particular, a coded block flag (CBF) is used to indicate whether a block or subsection has residual data or not after quantization. In general, a block with a CBF of 1 (ie, there is residual data after quantization) has more distortion than a block with a CBF of 0 (ie, there is no residual data after quantization). In this embodiment, a deblocking filter is applied to a boundary between two subdivisions based on the CBF flag of its two adjacent subsections.

In one example, if each of two subsections of a subsection boundary has a CBF flag value of 0, then no deblocking filter is applied, else (if at least one of the two subsections of a subsection boundary has a CBF flag value of 1) a deblocking filter is applied , the subsection boundary value Bs is set to 1. Returning to the example in Figure 6, if each of subsection 0 and 1 has a CBF flag of 0, then no deblocking filter for subsection boundary A is applied. If at least one of the partitions 0 and 1 has a CBF flag of 1, then a deblocking filter is applied to the border A of the partitions with Bs set to 1.

In one example, if each of two subsections of a subsection boundary has a CBF flag value of 0, then no deblocking filter is applied, else (if at least one of the two subsections of a subsection boundary has a CBF flag value of 1) a deblocking filter is applied with subsection boundary value Bs set to 2. Returning to the example in Figure 6, if subsection 0 and 1 each have a CBF flag of 0, then no deblocking filter for subsection boundary A is applied. If at least one of the partitions 0 and 1 has a CBF flag of 1, then a deblocking filter is applied to the border A of the partitions with Bs set to 2.

Sets a constant border intensity for subsection borders.

In one example, for all of the boundaries A, B, and C of the subsections shown in FIG. 6, the constant boundary intensity (Bs) is set to 1.

In another example, for all boundaries A, B, and C of the subsections shown in FIG. 6, the constant boundary intensity (Bs) is set to 2.

As shown in FIG. 8, according to another example, after coding block 800 is horizontally divided into subsections 801 or after coding block 800 is vertically divided into subsections 802, only subsection boundaries that overlap with the 8x8 sample grid are released, and the remaining subsection edges are not released. This has the advantage of reducing computational complexity since only a few edges are unlocked.

Another alternative is shown in Fig. 9. In this case, after the horizontal division of the coding block 900 into subsections 901 or after the vertical division of the coding block 900 into subsections 902, all subsection boundaries that overlap with the 4×4 grid of samples are released.

The position coordinator is defined as (x, y), x represents the number of samples from the top left sample of the entire frame in the horizontal direction; y represents the number of samples from the top left sample of the entire frame in the vertical direction. The coordinator of the top left sample of the entire frame is (0, 0).

In one example, an 8×8 grid of samples may start at position (x, y), where x%8==0. The % operation means the modulo operation, defined as the remainder of dividing x by 8.

In one example, the 8×8 grid of samples may start at position (x, y), where x%8==4. The % operation means the modulo operation, defined as the remainder of dividing x by 8.

In one example, an 8×8 grid of samples may start at position (x, y) where y%8==0. The % operation means the modulo operation, defined as the remainder of dividing y by 8.

In one example, the 8×8 grid of samples may start at position (x, y), where y%8==4. The % operation means the modulo operation, defined as the remainder of dividing y by 8.

Working with smaller blocks

Using an ISP may result in subsections that are 4 samples high or wide. The example in Figure 6 uses a vertical split, if W is 16 samples, then each subsection is 4 samples wide. In this case, as shown in FIG. 10, a weak filter can be used that modifies at most one sample 10314 or 10331 along the subsection boundary 1032 between subsection 1031 and subsection 1033. In the example shown in Figure 10, filtering is performed on each row of subsections 1031, 1033 that is perpendicular to and adjacent to subsection boundary 1032 between subsection 1031 and subsection 1033, for example. As shown in FIG. 10, a weak filter can be used that only modifies at most one sample 1108 or 10311 along the edge 1020 between adjacent block 1010 and current block 1030. In another example, shown in Figure 10, filtering is performed on each row of subsection 1031 or adjacent block 1010, which is perpendicular to and adjacent to the edge 1020 between adjacent block 1010 and subsection 1031 of block 1030, for example. Otherwise (if the height/width of the subsection orthogonal to the subsection boundaries is greater than 4 samples, then a deblocking filter (for example, the deblocking filter disclosed in the aforementioned VVC document) can be used according to JVET-L1001 version 13 of normal VVC ( http://phenix.it -sudparis.eu/jvet/doc_end_user/current_document.php?id=4834 ).

In another embodiment, for any of the above embodiments and examples, when the subsection boundaries are not aligned with the 8×8 grid, then no deblocking filter is applied.

Details of the intra-subsection related definition of the proposed method are given below in the format of the VVC project specification (parts 7.3.9.5 and 7.4.10.5):

7.3.9.5 Syntax of a coding unit

… intra_subpartitions_mode_flag [ x0 ][ y0 ] ae(v) if( intra_subpartitions_mode_flag[ x0 ][ y0 ] = = 1 ) intra_subpartitions_split_flag [ x0 ][ y0 ] ae(v) …

7.4.10.5 Semantics of a coding unit

intra_subpartitions_mode_flag [ x0 ][ y0 ] equal to 1 specifies that the current intra coding unit is divided into NumIntraSubPartitions[ x0 ][ y0 ] of rectangular transform block subpartitions. intra_subpartitions_mode_flag[ x0 ][ y0 ] equal to 0 specifies that the current intra coding unit is not divided into rectangular transform block subpartitions.

When intra_subpartitions_mode_flag[ x0 ][ y0 ] is not present, it is inferred to be 0.

intra_subpartitions_split_flag [ x0 ][ y0 ] specifies whether the type of intra-partitioning is horizontal or vertical. When intra_subpartitions_split_flag[ x0 ][ y0 ] is not present, it is output as follows:

- If cbHeight is greater than MaxTbSizeY, intra_subpartitions_split_flag[ x0 ][ y0 ] is output as 0.

- Otherwise (cbWidth is greater than MaxTbSizeY), intra_subpartitions_split_flag[ x0 ][ y0 ] is output as 1.

The variable IntraSubPartitionsSplitType specifies the type of partitioning used for the current luma coding block, as illustrated in Table 13. The IntraSubPartitionsSplitType is obtained as follows:

- If intra_subpartitions_mode_flag[ x0 ][ y0 ] is 0, IntraSubPartitionsSplitType is set to 0.

- Otherwise, IntraSubPartitionsSplitType is set to 1+intra_subpartitions_split_flag[ x0 ][ y0 ].

Table 13 - Name Relationship to IntraSubPartitionsSplitType

IntraSubPartitionsSplitType Name IntraSubPartitionsSplitType 0 ISP_NO_SPLIT one ISP_HOR_SPLIT 2 ISP_VER_SPLIT

The NumIntraSubPartitions variable determines the number of transform block subparts into which the luminance intra-coding block is divided. NumIntraSubPartitions is obtained like this:

- If IntraSubPartitionsSplitType is ISP_NO_SPLIT, NumIntraSubPartitions is set to 1.

- Otherwise, if one of the following conditions is true, NumIntraSubPartitions is set to 2:

-- cbWidth is 4 and cbHeight is 8,

-- cbWidth is 8 and cbHeight is 4.

- Otherwise, NumIntraSubPartitions is set to 4.

FIG. 11 is a flowchart of a deblocking method for deblocking a subsection boundary in a coding block in image encoding and/or image decoding, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection , which is adjacent to the first subsection, with the second subsection intra-predicted based on the first subsection. Additional details of the method are described above, for example with reference to FIG. from 6 to 10 .

Step 1101 determines the first maximum filter length to be 1 for the first subsection and/or the second maximum filter length to be 1 for the second subsection when the first subsection is 4 samples wide or the second subsection is 4 samples wide or when the first subsection is 4 samples high or the height of the second subsection is 4 samples;

At 1102, the value of at most one sample of the first subsection is modified, wherein the sample of at most one is obtained from the row or column of the first subsection that is/is perpendicular/perpendicular to and adjacent to the subsection boundary between the first subsection and the second subsection; and/or

In step 1103, the value of at most one second subsection sample is modified, whereby at most one sample is obtained from the row or column of the second subsection that is/is perpendicular/perpendicular to and adjacent to the subsection boundary between the first subsection and the second subsection.

Based on the above, the present disclosure allows a small number of sample values to be modified at a subsection boundary, and therefore the method can reduce blocking artifact that may be caused by subsection boundaries in a block in which ISP is applied, thus improving coding efficiency.

FIG. 12 is a flowchart of a deblocking method for deblocking block edges between image blocks in image encoding and/or image decoding, wherein the block edges comprise an edge between a current subsection of a current coding block and an adjacent block of that current coding block, wherein the current coding block encoded in intra-prediction mode, and the current coding block is divided into subsections; Additional details of the method are described above, for example with reference to FIG. from 6 to 10.

At step 1201, determine the third maximum filter length equal to 1 for the current subsection and/or the fourth maximum filter length equal to 1 for the neighboring block, when the width of the current subsection is 4 samples or the height of the current subsection is 4 samples;

At 1202, the value of at most one sample of the current subsection is modified, whereby that sample of at most one is obtained from a row or column of the current subsection that is/is perpendicular/perpendicular to and adjacent to the edge between the current subsection and an adjacent block; and/or

In step 1203, the value of at most one neighboring block sample is modified, wherein at most one sample of the neighboring block is obtained from the row or column of the neighboring block that is/is perpendicular/perpendicular to and adjacent to the edge between the current subsection and the neighboring block.

Based on the above, the present disclosure allows a small number of sample values to be modified at a subsection boundary, and therefore the method can reduce the blocking artifact that can be caused by subsection boundaries in a block in which ISP is applied, while avoiding filtering overlaps between the block edge and the boundary. subsections to a certain extent, thereby improving coding efficiency.

FIG. 13 is a block diagram illustrating an exemplary apparatus 1300 for deblocking a subsection boundary in a coding block according to the techniques described in this disclosure (more details will be described below, for example, based on FIGS. 2 and 3, as well as FIGS. 6 through 10) . Device for use in an image encoder and/or image decoder for deblocking a subsection boundary in a coding block, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection that is adjacent to the first subsection , in the example, the second subsection is intra-predicted based on the first subsection;

wherein the device 1300 includes a deblocking filter 1310 configured to:

- defining a first maximum filter length of 1 for the first subsection and/or a second maximum filter length of 1 for the second subsection when the width of the first subsection is 4 samples or the width of the second subsection is 4 samples or when the height of the first subsection is 4 samples or the height of the second subsection is 4 samples;

- modifications to the value of at most one sample of the first subsection, whereby this sample of at most one is obtained from a row or column of the first subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection; and/or

- value modifications of at most one sample of the second subsection, whereby this sample of at most one is obtained from a row or column of the second subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection.

FIG. 14 is a block diagram illustrating an exemplary device 1400 for deblocking block edges according to the techniques described in this disclosure (more details will be described below, for example, based on FIGS. 2 and 3, and FIGS. 6 through 10). An apparatus for use in an image encoder and/or image decoder, wherein the block edges comprise an edge between the current subsection of the current coding block and an adjacent block of the current coding block, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections;

wherein the device 1400 includes a deblocking filter 1410 configured to:

- determining a third maximum filter length equal to 1 for the current subsection and/or a fourth maximum filter length equal to 1 for the neighboring block, when the width of the current subsection is 4 samples or the height of the current subsection is 4 samples;

- modifying the value of at most one sample of the current subsection, whereby that sample of at most one is obtained from a row or column of the current subsection that is perpendicular to and adjacent to the edge between the current subsection and the adjacent block; and/or

- modifications to the value of at most one neighboring block sample, whereby this sample of at most one is obtained from a row or column of the neighboring block that is perpendicular and adjacent to the edge between the current subsection and the neighboring block.

FIG. 15 is a flowchart of a coding method implemented in a decoding apparatus or an encoding apparatus.

In step 1501, a reconstructed block of the current coding block that belongs to the current picture is generated, the current coding block is encoded in intra-prediction mode, and the current coding block is divided into sub-sections containing a first sub-section and a second sub-section, the second sub-section being intra-predicted based on the first subsection; and

In step 1502, filtering is performed on the reconstructed image of the current image, wherein performing filtering on the reconstructed image of the current image comprises: filtering at most one sample in the current subsection from the reconstructed subsections of the reconstructed block when the height of the current subsection is 4 samples, or when the width of the current of a subsection is 4 samples, wherein said sample of at most one is located in a row or column of the current subsection that is perpendicular to the boundary between the current subsection and another subsection that is adjacent to the current subsection, and this one sample is adjacent to the said boundary.

In some form of implementation of this embodiment, the value of said one sample, which is obtained from the column of the current subsection, which is perpendicular to and adjacent to the boundary between the current subsection and said other subsection, which is below or above the current subsection, is modified when the height of the current subsection is 4 samples if the type of intra-subpartitioning for subdividing the current coding block into subsections is horizontal.

In some form of implementation of this embodiment, the value of said one sample, which is obtained from the row of the current subsection, which is perpendicular to and adjacent to the boundary between the current subsection and said other subsection, which is to the left or right of the current subsection, is modified when the width of the current subsection is 4 samples if the intra-subsection type for subdividing the current coding block into subsections is vertical.

In some form of implementation of this embodiment, if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the boundary between the current subsection and said other subsection that is adjacent to the current subsection is a horizontal subsection boundary; or

if the type of intra-subsection for dividing the current coding block into subsections is vertical, the boundary between the current subsection and said other subsection which is adjacent to the current subsection is a vertical subsection boundary.

In some form of implementation of this embodiment, if the intra-subsection type for sub-dividing the current coding block into sub-sections is vertical, the first sub-section is to the left of the second sub-section and the second sub-section is intra-predicted based on the recovered value of the first sub-section;

In some form of implementation of this embodiment, if the type of intra-subsection for subdividing the current coding block into subsections is horizontal, the first subsection is on top of the second subsection and the second subsection is intra-predicted based on the recovered value of the first subsection.

In some form of implementation of this embodiment, the current sub-section is a restored version of the first sub-section or a restored version of the second sub-section.

In some form of implementation of this embodiment, the number of subsections is 2 or 4.

In some form of implementation of this embodiment

- if the coding block width is 4 and the coding block height is 8 and/or if the coding block width is 8 and the coding block height is 4, the number of subsections is 2,

- otherwise the number of subsections is 4.

In a further possible implementation form of this embodiment, filtering at most one sample in the current subsection is only performed if the boundary between the current subsection and another subsection overlaps with an n x n grid of reconstructed block samples, where n is an integer. For example, n=4 or n=8. Thus, the computational load can be further reduced.

In a further possible implementation form of this embodiment

filtering at most one selection in the current subsection is only done when all subsections are 4 selections high, or when all subsections are 4 selections wide. Thus, the computational load of the entire encoding process can be further reduced.

In particular, subsections are rectangular subsections of a transform block. When the ISP is split, each subsection is a transform block.

In the present disclosure, a coding block is encoded using an intra-partition tool, ISP.

In a further possible implementation form of this embodiment, the order of intra-subsection prediction is left-to-right or right-to-left order if the type of intra-subsection for subdividing the current coding block into subsections is vertical (e.g., division of a prediction block into subsections may be performed in the vertical direction ) or

the intra-subsection order is top-down or bottom-up if the intra-subsection type for subdividing the current coding block into subsections is horizontal (for example, division of the prediction block into subsections may be performed in a horizontal direction).

In particular, the current subkey is a restored version (ie, restored values) of the first subkey or a restored version (ie, restored values) of the second subkey. For example, the number of subsections may be 2 or 4.

The encoding block may be encoded using the intra-subdivision tool, ISP. The ISP coding tool only applies to the intra-prediction coding block. Splitting the coding block/intra-prediction block may result in 1D subsections or a subsection line. If this method is intended to be used in image coding, the generation of the reconstructed block is based on the following processing flow (known in the art): calculation of the residual block based on the current block (i.e., the original block) and the intra-prediction block, transformation and quantization residual coefficients of the residual block, inverse quantization, and inverse transform to obtain a reconstructed residual block (see also the detailed description below). The recovered block is obtained based on the recovered residual block and the prediction block. If this method is intended to be used in image decoding, the generation of the reconstructed block is based on the following processing flow (known in the art): obtaining the residual coefficients of the residual block based on the information included in the received bitstream, transforming and quantizing the residual coefficients of the residual block, inverse quantization and inverse transformation to obtain a reconstructed residual block (see also the detailed description below). The recovered block is obtained based on the recovered residual block and the prediction block. In addition, the reconstructed image of the current image containing the current block is introduced into the filtering process, in a block-based image coding scheme, with no more than one sample filtering, which is understood as border filtering containing a modification of no more than one sample adjacent to the block boundary. The decision on this type of release can be based on only three selections (adjacent in the same row to filter boundaries between vertical subsections, or adjacent in the same column to filter boundaries between horizontal subsections; see also the detailed description above).

In general, the border intensities of all borders between subsections of a coding block may be set to a constant value indicating the strength of the filtering process (eg, 2) to simplify overall processing.

The weak filtering applied according to the invention (no more than one sample) allows to reduce blocking artifacts in small blocks without the need for excessively high computational load and memory resources.

FIG. 16 is a flowchart of another coding method implemented in a decoding apparatus or an encoding apparatus.

Step 1601 generates a reconstructed block of the current coding block that belongs to the current picture, wherein the current coding block is encoded in intra-prediction mode, and the current coding block is divided into sub-sections containing a first sub-section and a second sub-section, the second sub-section being intra-predicted based on the first subsection; and

In step 1602, filtering is performed on the reconstructed image of the current image, wherein performing filtering on the reconstructed image of the current image comprises: filtering the boundary between the current subsection of the reconstructed block and a neighboring block that is adjacent to the current subsection (i.e., a neighboring block of the current block), on based on the maximum filter length of the current subsection and the maximum length of the neighboring block filter, and the maximum filter length of the current subsection and the maximum length of the neighboring block filter is 1 when the height of the current subsection is 4 samples or when the width of the current subsection is 4 samples.

In an example, block 1602 may include:

- modifying, based on the maximum filter length MA of the current subsection, the value of one sample of the current subsection adjacent to the boundary; and

- modification, based on the maximum neighbor block filter length MB, of neighboring block sample values adjacent to the boundary.

MA=1, MB=1.

In particular, step 1203 may include:

- modifying the value of the sample maximum in the number MA of the current subsection, and the sample maximum in the number MA is on a line perpendicular to and adjacent to the boundary, MA=1; and

while the modification, based on the maximum filter length MB, of the sample values of the neighboring block adjacent to the boundary, contains:

- modification of the values of samples at most in the number of MBs of the neighboring block, and the samples at most in the number of MBs are on the line perpendicular to and adjacent to the boundary, MB=1.

Here, the maximum filter length of the current subsection means the number of samples allowed for modification in the filtering process for the current subsection. The maximum length of the neighbor block filter means the number of samples allowed for modification in the filtering process for the neighbor block.

In some form of implementation of this embodiment, the first subsection is intra-predicted based on another reconstructed block that is adjacent to the coding block.

In a further possible implementation form of this embodiment, filtering is performed only if the boundary overlaps with an n x n grid of reconstructed block samples, where n is an integer. For example, n is 4 or 8.

In some form of implementation of this embodiment, the value of said one sample, which is obtained from the column of the current subsection, which is perpendicular to and adjacent to the boundary between the current subsection and said neighboring block, which is below or above the current subsection, is modified when the height of the current subsection is 4 samples if the type of intra-subpartitioning for subdividing the current coding block into subsections is horizontal.

In some form of implementation of this embodiment, the value of said one sample, which is obtained from the row of the current subsection, which is perpendicular to and adjacent to the boundary between the current subsection and said adjacent block, which is to the left or right of the current subsection, is modified when the width of the current subsection is 4 samples if the intra-subsection type for subdividing the current coding block into subsections is vertical.

In some form of implementation of this embodiment, if the type of intra-subpartitioning for dividing the current coding block into subsections is horizontal, the boundary between the current subsection and said neighboring block, which is adjacent to the current subsection, is a horizontal boundary; or

if the intra-subpartition type for dividing the current coding block into subsections is vertical, the boundary between the current subsection and said neighboring block which is adjacent to the current subsection is a vertical boundary.

In some form of implementation of this embodiment, if the intra-subsection type for sub-dividing the current coding block into sub-sections is vertical, the first sub-section is to the left of the second sub-section and the second sub-section is intra-predicted based on the recovered value of the first sub-section;

if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the first subsection is on top of the second subsection, and the second subsection is intra-predicted based on the recovered value of the first subsection.

Specifically, the number of sub-sections is 2 or 4. When the number of sub-sections is 2, respectively, there is a first sub-section and a second sub-section within the current block, and the current sub-section may be a restored version of the first sub-section or a restored version of the second sub-section.

When the number of sub-sections is 4, respectively, there is a first sub-section, a second sub-section, a third sub-section and a fourth sub-section within the current block, and the current sub-section may be a restored version of the first sub-section or a restored version of the fourth sub-section.

It can be understood that the first subsection, the second subsection, the third subsection, and the fourth subsection are simply used differently for subsections. In some cases, the height of all subsections is 4 samples, or the width of all subsections is 4 samples.

In a further possible form of implementation of this embodiment

- if the coding block width is 4 and the coding block height is 8 and/or if the coding block width is 8 and the coding block height is 4, the number of subsections is 2,

- otherwise the number of subsections is 4.

In a further possible implementation form of this embodiment, filtering is performed only if the boundary overlaps with an n x n grid of reconstructed block samples, where n is an integer. For example, n is 4 or 8.

In particular, subsections are rectangular subsections of a transform block.

In the present disclosure, a coding block is encoded using an intra-partition tool, ISP.

FIG. 17 is a block diagram illustrating an exemplary apparatus 1700 according to the techniques described in this disclosure (more details will be described below, for example, based on FIGS. 6 through 10 as well as FIG. 15). The device is intended for use in an image encoder and/or image decoder. In an example, this device 1700 may correspond to the encoder of FIG. 2. In another example, this device 1700 may correspond to the decoder of FIG. 3. The device may include:

a reconstructor 1710, configured to generate a reconstructed block of the current coding block that belongs to the current image, wherein the current coding block is encoded in intra-prediction mode, and the current coding block is divided into subsections comprising a first subsection and a second subsection, wherein the second subsection is intra -predicted on the basis of the first subsection; and

a filtering unit 1730, configured to perform filtering on the reconstructed image of the current image, wherein the filtering unit 1730 is specifically configured to filter at most one sample in the current subsection from the reconstructed subsections of the reconstructed block, when the height of the current subsection is 4 samples, or when the width of the current subsection is 4 samples, said one sample being located in a row or column of the current subsection that is perpendicular to the boundary between the current subsection and another subsection that is adjacent to the current subsection, and that one sample is adjacent to said boundary.

FIG. 18 is a block diagram illustrating an exemplary apparatus 1800 according to the techniques described in this disclosure (more details will be described below, for example, based on FIGS. 6 through 10 as well as FIG. 16). The device is intended for use in an image encoder and/or image decoder. In an example, this device 1800 may correspond to the encoder of FIG. 2. In another example, this device 1800 may correspond to the decoder of FIG. 3. The device may include:

a reconstructor 1810, configured to generate a reconstructed block of the current coding block that belongs to the current image, wherein the current coding block is encoded in intra-prediction mode, and the current coding block is divided into subsections comprising a first subsection and a second subsection, wherein the second subsection is intra -predicted on the basis of the first subsection; and

a filtering unit 1830, configured to perform filtering on the reconstructed image of the current image, wherein the filtering unit 1830 is specifically configured to filter the boundary between the current subsection of the reconstructed block and an adjacent block that is adjacent to the current subsection, based on the maximum filter length of the current subsection and the maximum neighbor block filter length, and the respective maximum filter lengths of the current subsection and the neighboring block are 1 when the height of the current subsection is 4 samples or when the width of the current subsection is 4 samples.

Based on the above, the present disclosure allows a small number of sample values to be modified at a subsection boundary, and therefore the method can reduce the blocking artifact that can be caused by subsection boundaries in a block in which ISP is applied, while avoiding filtering overlaps between the block edge and the boundary. subsections to a certain extent, thereby improving coding efficiency.

The following is an explanation on the applications of the encoding method and the decoding method shown in the above embodiments, as well as the system using them.

FIG. 19 is a block diagram showing a content supply system 3100 for realizing a content distribution service. This content delivery system 3100 includes a capture device 3102, a terminal device 3106, and optionally includes a display 3126. The capture device 3102 communicates with the terminal device 3106 over a communication line 3104. The communication link may include the communication channel 13 described above. Link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G/4G/5G), USB, or any combination thereof, or the like.

The capture device 3102 generates data and may encode the data in the encoding method shown in the above embodiments. Alternatively, the capture device 3102 may distribute the data to a streaming server (not shown in the Figures) and the server encodes the data and transmits the encoded data to the terminal device 3106. The capture device 3102 includes, but is not limited to, a camera, smartphone, or tablet , a computer or laptop, a videoconferencing system, a PDA, a vehicle-mounted device, or a combination of any of these, or the like. For example, capture device 3102 may include source device 12 described above. When the data includes video, the video encoder 20 included in the capture device 3102 may actually perform video encoding processing. When the data includes audio (ie, speech), the audio encoder included in the capture device 3102 may actually perform audio encoding processing. For some practical scenarios, the capture device 3102 distributes encoded video and audio data by co-multiplexing them. For other practical scenarios, such as in a videoconferencing system, encoded audio data and encoded video data are not multiplexed. The capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.

In the content delivery system 3100, the terminal device 310 receives and reproduces the encoded data. The terminal device 3106 may be a device with the ability to receive and retrieve data, such as a smartphone or tablet 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a television 3114, a set-top box (STB) 3116, a videoconferencing system 3118 , a video surveillance system 3120, a personal digital assistant (PDA) 3122, a vehicle-mounted device 3124, or a combination thereof, or the like, capable of decoding the aforementioned encoded data. For example, terminal device 3106 may include sink device 14 described above. When the encoded data includes video, the video decoder 30 included in the terminal device is given priority to perform video decoding. When the encoded data includes audio, an audio decoder included in the terminal device is given priority to perform audio decoding processing.

For a terminal device with its own display, such as a 3108 smartphone or tablet, 3110 computer or laptop, 3112 Network Video Recorder (NVR)/Digital Video Recorder (DVR), 3114 TV, 3122 Personal Digital Assistant (PDA), or 3124 Vehicle Mounted Device, terminal the device can send the decoded data to its display. For a non-display terminal device, such as an STB 3116, a video conferencing system 3118, or a video surveillance system 3120, it is contacted with an external display 3126 to receive and display decoded data.

When each device in this system performs encoding or decoding, an image encoding device or an image decoding device may be used as shown in the above embodiments.

FIG. 20 is a diagram showing the structure of an exemplary terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, the protocol processing unit 3202 parses the transmission protocol of said stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), Interchange Protocol real-time messaging (RTMP) or any combination thereof, or the like.

After the protocol processing unit 3202 processes the stream, a stream file is generated. The file is output to the demultiplexer 3204 . A demultiplexer 3204 may separate the multiplexed data into encoded audio data and encoded video data. As described above, in other practical scenarios, such as in a videoconferencing system, encoded audio data and encoded video data are not multiplexed. In this situation, the encoded data is transmitted to the video decoder 3206 and audio decoder 3208 without using the demultiplexer 3204.

Through the demultiplexing processing, elementary stream (ES) video, ES audio, and optionally subtitles are generated. The video decoder 3206, which includes the video decoder 30 described in the above embodiments, decodes the ES video using the decoding method as shown in the above embodiments to generate a video frame, and supplies this data to the sync block 3212. The audio decoder 3208 decodes the ES audio to generate audio frame and feeds the data to sync block 3212. Alternatively, a video frame may be stored in a buffer (not shown in FIG. Y) before being fed to sync block 3212. Similarly, an audio frame may be stored in a buffer (not shown in FIG. Y) before it is fed into the 3212 synchronizing block.

The sync block 3212 synchronizes the video frame and the audio frame and supplies video/audio to the video/audio display 3214. For example, the sync block 3212 synchronizes the presentation of video and audio information. The information may be encoded in a syntax using timestamps regarding the presentation of the encoded audio and video data, as well as timestamps regarding the delivery of the data stream itself.

If the subtitle is included in the stream, the subtitle decoder 3210 decodes the subtitle and synchronizes it with the video frame and the audio frame and transmits the video/audio/subtitle to the video/audio/subtitle display 3216.

The present invention is not limited to the above system, and either the image encoding device or the image decoding device of the above embodiments may be included in another system such as an automobile system.

The invention has been described in connection with various embodiments herein. However, other variations of the disclosed embodiments may be understood and practiced by those skilled in the art in the practice of the claimed invention based on examination of the drawings, this disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and mentioning something in the singular does not exclude plurality. One processor or other block can perform the functions of several elements specified in the claims. The mere fact that certain measures are set forth in generally different dependent claims does not mean that a combination of these measures cannot be used to advantage. The computer program may be stored/distributed on a suitable medium, such as an optical storage medium or solid state media provided with or as part of other hardware, but may also be distributed in other forms, such as over the Internet or other wired or wireless communication systems.

One skilled in the art will appreciate that the "blocks" ("modules") in the various figures (method and apparatus) represent or describe the functionality of embodiments of the invention (rather than necessarily individual "blocks" in hardware or software) and thus they equally describe the functions or features of device embodiments as well as method embodiments (block=step).

The term "block" is used for purposes of illustrating the functionality of encoder/decoder embodiments only and is not intended to limit this disclosure.

In several embodiments presented in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiment described is exemplary only. For example, the division into blocks is only a logical division into functions, and in the actual implementation, another division may take place. For example, many blocks or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the interconnections or direct links or communication connections shown or described may be implemented using certain interfaces. Indirect connections or communication connections between devices or units can be implemented electrically, mechanically, or take other forms.

Blocks described as separate parts may or may not be physically separate, and parts shown as blocks may or may not be physical blocks, may be located in the same location, or may be distributed over multiple network blocks. Some or all of the blocks may be selected according to actual requirements to achieve the goals of the decisions in the embodiments.

In addition, the functional blocks in the embodiments of the present invention may be integrated into one processing unit, or each of the units may physically exist separately, or two or more units are integrated into one unit.

Embodiments of the invention may further include an apparatus, such as an encoder and/or decoder, that includes a processing circuit configured to perform any of the methods and/or processes described herein.

Although embodiments of the present invention have been primarily described in terms of video coding, it should be noted that embodiments of encoding system 10, encoder 20, and decoder 30 (and thus system 10), as well as other embodiments described herein, may also be configured to process or encode a still image, i. e. processing or encoding a single image independently of any preceding or subsequent image, as in video encoding. In general, only inter-prediction (encoder) and 344 (decoder) blocks 244 may not be available if the encoding for image processing is limited to a single image 17. All other functionality (also referred to as tools or technologies) of video encoder 20 and video decoder 30 can equally be used for still image processing, e.g., residual calculation 204/304, transform 206, quantization 208, inverse quantization 210/310, (inverse) transform 212/312, split 262/362, intra-prediction 254/354 and/ or loop filtering 220, 320 and entropy encoding 270 and entropy decoding 304.

Embodiments such as encoder 20 and decoder 30, as well as the functions described herein, such as encoder 20 and decoder 30, may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted over a communication medium as one or more instructions or code and executed by a hardware processing unit. Computer-readable media may include computer-readable media that corresponds to a tangible medium, such as a storage medium, or a communication medium, including any medium that allows a computer program to be transferred from one place to another, such as according to a communication protocol. Thus, computer-readable media can typically correspond to (1) tangible computer-readable media that is durable, or (2) a communication medium such as a signal or carrier wave. Storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and/or data structures for implementing the techniques described in this disclosure. The computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other media that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. However, it should be understood that computer-readable and storage media do not include connections, carrier waves, signals, or other short-lived media, but are instead directed to long-term, tangible storage media. The disc (disk) and disc (disc) used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where discs (disks ) usually reproduce data magnetically, while disks (discs) reproduce data optically using lasers. Combinations of the above should also be included in the scope of computer-readable media.

The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Accordingly, the term "processor" as used herein may refer to any of the aforementioned structures, or any other structure suitable for implementing the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within specialized hardware and/or software modules capable of encoding and decoding or included in a combined codec. In addition, the techniques may be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or hardware components, including a wireless telephone, an integrated circuit (IC), or an IC stack (eg, a chipset). This disclosure describes various components, modules, or blocks to emphasize the functional aspects of devices capable of performing the disclosed technologies, but not necessarily requiring implementation in different hardware blocks. Rather, as described above, various blocks may be combined into a codec hardware block, or provided by a collection of cooperating hardware blocks, including one or more processors, as described above, along with suitable software and/or firmware.

Claims (56)

1. A deblocking method for deblocking a subsection boundary in a coding block in image encoding or image decoding, in which the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection that is adjacent to the first subsection, wherein the method comprises: - defining a first maximum filter length of 1 for the first subsection when the first subsection width is 4 samples or the second subsection width is 4 samples, or when the first subsection height is 4 samples or the second subsection height is 4 samples; and/or - defining a second maximum filter length of 1 for the second subsection when the first subsection width is 4 samples or the second subsection width is 4 samples, or when the first subsection height is 4 samples or the second subsection height is 4 samples; - doing one or more of: -- modifications, based at least in part on the first maximum length of the filter, to values of at most one sample of the first subsection, where that sample of at most one is derived from a row or column of the first subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection; or -- modifications, based at least in part on the second maximum length of the filter, to values of at most one sample of the second subsection, where that sample of at most one is derived from a row or column of the second subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection. 2. The method according to claim 1, wherein the sample of at most one, which is obtained from the column of the first or second subsection, which is perpendicular to and adjacent to the border of subsections between the first and second subsections, is modified when the height of the first or second subsection is 4 samples and if the type of intra-subsectioning for subdividing the current coding block into subsections is horizontal. 3. The method according to claim 1, wherein the sample of at most one, which is obtained from the row of the first or second subsection, which is perpendicular to and adjacent to the border of subsections between the first and second subsections, is modified when the width of the first or second subsection is 4 samples and if the intra-subsection type for subdividing the current coding block into subsections is vertical. 4. The method according to any one of paragraphs. 1-3, in which, if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the subsection boundary between the first and second subsections is a horizontal subsection boundary; or if the intra-subsection type for subdividing the current coding block into subsections is vertical, the subsection boundary between the first and second subsections is a vertical subsection boundary. 5. The method according to any one of paragraphs. 1-3, in which, if the type of intra-subsection for dividing the current coding block into subsections is vertical, the first subsection is located to the left of the second subsection, and the second subsection is intra-predicted based on the recovered value of the first subsection; and if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the first subsection is positioned on top of the second subsection, and the second subsection is intra-predicted based on the recovered value of the first subsection. 6. The method according to any one of paragraphs. 1-5, in which the number of subsections in the current coding block is 2 or 4. 7. The method according to any one of paragraphs. 1-6, in which if the width of the current coding block is 4 and the height of the coding block is 8, or if the width of the current coding block is 8 and the height of the current coding block is 4, the number of subsections in the current coding block is 2, otherwise, the number of subsections is 4. 8. The method according to any one of paragraphs. 1-7, in which a sample of at most one in the first or second subsection is modified even if the subsection boundary between the first and second subsections does not overlap with an n x n grid of samples, where n is 4 or 8. 9. The method according to any one of paragraphs. 1-7, in which a sample of at most one in the first or second subsection is modified only if the subsection boundary between the first and second subsections overlaps with an n x n grid of samples, where n is 4 or 8. 10. The method of one of the preceding claims, wherein the subsection samples are luminance samples or the subsection samples are chrominance samples. 11. The method of one of the preceding claims, wherein the subsections are rectangular subsections of the transform block. 12. The method according to one of the preceding claims, wherein the intra-subsection prediction order is left-to-right order, if the intra-subsection type for subdividing the current coding block into subsections is vertical, or in which the intra-subsection prediction order is top-down order if the intra-subsection partitioning type for subdividing the current coding block into subsections is horizontal. 13. The method according to one of the preceding claims, wherein the current coding block is encoded using an intra-subdivision tool (ISP), or a sub-subsection boundary is generated by an intra-subdivision tool (ISP). 14. Apparatus for use in an image encoder or image decoder for deblocking a subsection boundary in a coding block, wherein the current coding block is encoded in intra-prediction mode and the current coding block is divided into subsections containing a first subsection and a second subsection that is adjacent to the first subsection ; wherein the device comprises a deblocking filter configured to: - defining a first maximum filter length of 1 for the first subsection when the first subsection width is 4 samples or the second subsection width is 4 samples, or when the first subsection height is 4 samples or the second subsection height is 4 samples; and/or - defining a second maximum filter length equal to 1 for the second subsection when the first subsection width is 4 samples or the second subsection width is 4 samples, or when the first subsection height is 4 samples or the second subsection height is 4 samples; and - performing one or more of: -- modifications, based at least in part on the first maximum length of the filter, to values of at most one sample of the first subsection, where that sample of at most one is derived from a row or column of the first subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection; or -- modifications, based at least in part on the second maximum length of the filter, to values of at most one sample of the second subsection, where that sample of at most one is derived from a row or column of the second subsection that is perpendicular to and adjacent to the boundary of the subsections between the first subsection and the second subsection. 15. The apparatus of claim 14, wherein no more than one sample that is obtained from a column of the first or second subsection that is perpendicular to and adjacent to the subsection boundary between the first and second subsections is modified when the height of the first or second subsection is 4 samples and if the type of intra-subsectioning for subdividing the current coding block into subsections is horizontal. 16. The apparatus of claim 14, wherein the sample of at most one that is obtained from the row of the first or second subsection that is perpendicular to and adjacent to the subsection boundary between the first and second subsections is modified when the width of the first or second subsection is 4 samples and if the intra-subsection type for subdividing the current coding block into subsections is vertical. 17. The device according to any one of paragraphs. 14-16, in which, if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the subsection boundary between the first and second subsections is a horizontal subsection boundary; or if the intra-subsection type for subdividing the current coding block into subsections is vertical, the subsection boundary between the first and second subsections is a vertical subsection boundary. 18. The device according to any one of paragraphs. 14-16, in which, if the intra-subsection type for dividing the current coding block into sub-sections is vertical, the first sub-section is to the left of the second sub-section, and the second sub-section is intra-predicted based on the recovered value of the first sub-section; and if the type of intra-subsection for dividing the current coding block into subsections is horizontal, the first subsection is on top of the second subsection, and the second subsection is intra-predicted based on the recovered value of the first subsection. 19. The device according to any one of paragraphs. 14-18, in which the number of subsections in the current coding block is 2 or 4. 20. The device according to any one of paragraphs. 14-19, in which - if the width of the current coding block is 4 and the height of the coding block is 8, and/or if the width of the current coding block is 8 and the height of the current coding block is 4, the number of subsections in the current coding block is 2, - otherwise the number of subsections is 4. 21. The device according to any one of paragraphs. 14-20, in which a sample of at most one in the first or second subsection is modified even if the subsection boundary between the first and second subsections does not overlap with an n x n sample grid where n is 4 or 8. 22. The device according to any one of paragraphs. 14-20, in which a sample of at most one in the first or second subsection is modified only if the subsection boundary between the first and second subsections overlaps with an n x n grid of samples, where n is 4 or 8. 23. The device according to any one of paragraphs. 14-22, in which the subsection samples are luminance samples or the subsection samples are chrominance samples. 24. The device according to any one of paragraphs. 14-23, in which the subsections are rectangular subsections of the transform block. 25. The device according to any one of paragraphs. 14-24, in which the order of intra-subsection prediction is the order from left to right, if the type of intra-subsection for dividing the current coding block into subsections is vertical, or in which the intra-subsection prediction order is top-down order if the intra-subsection partitioning type for subdividing the current coding block into subsections is horizontal. 26. The device according to any one of paragraphs. 14-25, in which the current coding block is encoded using an intra-subdivision tool (ISP), or a sub-section boundary occurs under an intra-subdivision tool (ISP). 27. Encoder (20), containing the processing circuit for performing the method according to any one of paragraphs. 1-13. 28. Decoder (30), containing the processing circuit for performing the method according to any one of paragraphs. 1-13. 29. A computer-readable medium containing program code that, when executed by a computing device, causes the computing device to perform the method according to any one of paragraphs. 1-13. 30. Decoder (30), containing: one or more processors; and a durable computer-readable medium associated with the processors and storing software for execution by the processors, wherein the software, when executed by the processors, configures a decoder to perform the method of any one of claims. 1-13. 31. Encoder (20), containing: one or more processors; and a durable computer-readable medium associated with the processors and storing software for execution by the processors, wherein the software, when executed by the processors, configures an encoder to perform the method of any one of claims. 1-13.

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