CN111294603B

CN111294603B - Video encoding and decoding method and device

Info

Publication number: CN111294603B
Application number: CN201911249011.2A
Authority: CN
Inventors: 赵寅; 杨海涛; 张恋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-12-06
Filing date: 2019-12-06
Publication date: 2023-09-29
Anticipated expiration: 2039-12-06
Also published as: CN111294603A; WO2020114508A1

Abstract

A video decoding method, device and corresponding coding and decoding equipment improve coding and decoding performance of a transformation unit to a certain extent. Wherein the method comprises the following steps: acquiring coding block identifiers (Coding Block Flag) of N-1 transformation tree child nodes in the N transformation tree child nodes, wherein N is an integer greater than 1; determining a value of a coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes based on the value of the coding block identification of the N-1 transform tree sub-nodes; and acquiring the decoded image block indicated by the current transformation tree node according to the coding block identifiers of the N transformation tree child nodes.

Description

Video encoding and decoding method and device

Technical Field

The present application relates to the field of video encoding and decoding technologies, and in particular, to a video encoding and decoding method and apparatus, and a corresponding encoding and decoding device.

Background

Digital video capabilities can be incorporated into a wide variety of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal Digital Assistants (PDAs), laptop or desktop computers, tablet computers, electronic book readers, digital cameras, digital recording devices, digital media players, video gaming devices, video game consoles, cellular or satellite radio telephones (so-called "smartphones"), video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video compression techniques such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4 part 10 Advanced Video Coding (AVC), the video coding standard H.265/High Efficiency Video Coding (HEVC) standard, and extensions of such standards. Video devices may more efficiently transmit, receive, encode, decode, and/or store digital video information by implementing such video compression techniques.

Video compression techniques perform spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or eliminate redundancy inherent in video sequences. For block-based video coding, a video slice (i.e., a video frame or a portion of a video frame) may be partitioned into tiles, which may also be referred to as treeblocks, coding Units (CUs), and/or coding nodes. Image blocks in a slice to be intra-coded (I) of an image are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same image. Image blocks in a to-be-inter-coded (P or B) stripe of an image may use spatial prediction with respect to reference samples in neighboring blocks in the same image or temporal prediction with respect to reference samples in other reference images. An image may be referred to as a frame and a reference image may be referred to as a reference frame.

The HEVC/h.265 video coding standard is a block-based coding scheme that first requires a frame of pictures to be partitioned into Coding Tree Units (CTUs) that do not overlap each other. The CTU may be further divided into a plurality of coding units CU according to a Quadtree (QT) structure, where each CU includes a luma Coding Block (CB) and two chroma Coding Blocks (CB) and corresponding syntax elements. The coding Unit CU may be further divided into one or more Prediction Units (PU) and Transform Units (TU).

The transform unit is a basic unit for performing transform and quantization, and is divided on the basis of a CU. In HEVC, CU-to-TU partitioning uses quadtree partitioning (QT), known as "transform tree" or residual quadtree (Residual Quad Tree, RQT). In jfet, a Three Tree (TT) division method may be used, or a Binary Tree (BT) division method may be used. The improvement of the coding and decoding performance of the transformation unit is one of the research directions of the current video compression technology.

Disclosure of Invention

The embodiment of the application provides a video coding and decoding method and device and corresponding coding and decoding equipment, which can improve coding and decoding performance of a transformation unit to a certain extent.

In a first aspect, embodiments of the present application provide a video decoding method, which is performed by a codec device or a codec apparatus. The method comprises the following steps:

acquiring coding block identifiers (Coding Block Flag) of N-1 transformation tree sub-nodes in N transformation tree sub-nodes of a current transformation tree node, wherein N is an integer greater than 1; determining a value of a coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes based on the value of the coding block identification of the N-1 transform tree sub-nodes; reconstructing the current transformation tree node according to the values of the coding block identifications of the N transformation tree child nodes.

The obtaining the coding block identifiers of the N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node may be analyzing the coding block identifiers of the N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node from the code stream.

The coding block identifiers of the N-1 transform tree sub-nodes may be at least one of coding block identifiers of the luminance component transform blocks, coding block identifiers of the blue chrominance component transform blocks, and coding block identifiers of the red chrominance component transform blocks of the N-1 transform tree sub-nodes. Accordingly, the coding block identifier of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes may be at least one of the coding block identifier of the luminance component transform block, the coding block identifier of the blue chrominance component transform block, and the coding block identifier of the red chrominance component transform block of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the method further includes:

acquiring a coding block identification (coding block flag) of the current transform tree node;

Correspondingly, the determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes comprises:

and determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes and the value of the coding block identifier of the current transform tree node.

In one implementation, the obtaining the coding block identification of the current transform tree node may include: and analyzing and acquiring the code block identification of the current transformation tree node from the code stream.

In one implementation, the obtaining the coding block identification of the current transform tree node may include: and determining the value of the code block identification of the current transformation tree node.

In one implementation, the current transform tree node is a Coding Unit (CU). The obtaining the code block identification of the current transform tree node may include: and obtaining the code block identification of the code unit. The coding unit syntax structure of the coding unit in the code stream to which the coding unit belongs is provided with a transformation tree syntax structure, wherein the value of the coding block identifier of the coding unit is 1 or the value of the coding block identifier of the coding unit indicates that the coding unit syntax structure of the coding unit in the code stream to which the coding unit belongs.

In one implementation, the current transform tree node may be a coding unit or a sub-block of a coding unit, and the coding block identifier of the current transform tree node may be at least one of a coding block identifier of a luma component transform block, a coding block identifier of a blue component transform block, and a coding block identifier of a red component transform block of the coding unit or the sub-block of the coding unit.

In one implementation, the determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-node and the value of the coding block identifier of the current transform tree node may include: determining whether the value of the code block identification of the current transform tree node indicates that the transform block of the current transform tree node contains non-zero transform coefficients, and determining whether the value of the code block identification of the N-1 transform tree sub-nodes indicates that none of the transform blocks of the N-1 transform tree nodes contains non-zero transform coefficients; in the case that it is determined that the value of the coding block identification of the current transform tree node indicates that the transform block of the current transform tree node contains non-zero transform coefficients and that the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the transform blocks of the N-1 transform tree nodes contains non-zero transform coefficients, it is determined that the value of the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicates that the transform block of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contains non-zero transform coefficients.

In one implementation, the determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-node and the value of the coding block identifier of the current transform tree node may include: determining whether the value of the coding block identifier of the current transformation tree node is 1 or not, and determining whether the values of the coding block identifiers of the N-1 transformation tree sub-nodes are 0 or not; in the case that the value of the code block identification of the current transform tree node is determined to be 1, and the values of the code block identifications of the N-1 transform tree sub-nodes are all 0, the value of the code block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes is determined to be 1.

In one implementation, the current transform tree node is a Coding Unit (CU). Further, the coding block identification of the current transform tree node may include: and the coding block identification of the coding unit. The determining a value of the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes according to the value of the coding block identification of the N-1 transform tree sub-nodes and the value of the coding block identification of the current transform tree node may include: determining whether a value of a coding block identifier of the coding unit indicates that a coding unit syntax structure of the coding unit in a code stream to which the coding unit belongs has a transform tree syntax structure, and determining whether values of coding block identifiers of the N-1 transform tree sub-nodes indicate that no transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients; in the case that it is determined that the value of the coding block identification of the coding unit indicates that the coding unit syntax structure of the coding unit in the code stream to which the coding unit belongs has a transform tree syntax structure, and that the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, it is determined that the value of the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicates that the transform block of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contains non-zero transform coefficients. With reference to the first aspect, in a second possible implementation manner of the first aspect, the determining, according to the value of the coding block identifier of the N-1 transform tree sub-nodes, a value of a coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except for the N-1 transform tree sub-nodes includes:

Determining whether to analyze the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes;

and determining the value of the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node under the condition that the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not analyzed.

Wherein not resolving the coding block identification of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes may mean that the coding block identification of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes does not appear in the code stream to which the current transform tree node belongs.

In one implementation, the determining whether to parse the coding block identifier of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes may include: determining whether the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the coding blocks of the N-1 transform tree nodes contain non-zero transform coefficients, the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the coding blocks of the N-1 transform tree nodes contain non-zero transform coefficients meaning that the coding block identification of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is not resolved, and the value of the coding block identification of the N-1 transform tree sub-nodes indicates that the coding block identification of at least one of the N-1 transform tree nodes contains non-zero transform coefficients meaning that the coding block identification of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is resolved.

In one implementation, the determining whether to parse the coding block identifier of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes may include: determining whether the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0, wherein the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0, meaning that the coding block identifications of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes are not analyzed, and the values of at least one of the values of the coding block identifications of the N-1 transform tree sub-nodes are 1, meaning that the coding block identifications of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes are analyzed.

In one implementation, the method further comprises: and under the condition that the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is determined to be analyzed, the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is analyzed from the code stream.

In one implementation, the determining the value of the encoded block identification of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes may include: and determining the value of the coding block identifier of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to a preset rule.

With reference to the first aspect or any one of the possible implementation manners of the first aspect, in a third possible implementation manner of the first aspect, in a case that it is determined that the current transform tree node is divided into N transform tree sub-nodes, the obtaining (Coding Block Flag) an encoded block identification of N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node is performed.

With reference to the first aspect or any one of the possible implementation manners of the first aspect, in four possible implementation manners of the first aspect, the N is 2,3 or 4.

With reference to the first aspect or any one of possible implementation manners of the first aspect, in a fifth possible implementation manner of the first aspect, the N-1 transform tree sub-nodes are first N-1 transform tree sub-nodes in the N transform tree sub-nodes.

With reference to the first aspect or any one of possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the N transform tree child nodes are N transform units (transform_units, TUs).

With reference to the first aspect or any one of possible implementation manners of the first aspect, in a seventh possible implementation manner of the first aspect, the current transform tree node is a Coding Unit (CU).

With reference to the first aspect or any one of possible implementation manners of the first aspect, in an eighth possible implementation manner of the first aspect, the determining, according to the value of the coded block identifier of the N-1 transform tree sub-nodes, a value of the coded block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except for the N-1 transform tree sub-nodes may include: determining whether values of coding block identifications of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients; in the case that it is determined that the values of the code block identifications of the N-1 transform tree sub-nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, determining that the values of the code block identifications (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicate that one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contain non-zero transform coefficients.

With reference to the first aspect or any one of the possible implementation manners of the first aspect, in a ninth possible implementation manner of the first aspect, the determining, according to the value of the coded block identifier of the N-1 transform tree sub-nodes, the value of the coded block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except for the N-1 transform tree sub-nodes may include: determining whether the values of the coding block identifications of the N-1 transformation tree child nodes are all 0; and under the condition that the values of the coding block identifications of the N-1 transformation tree sub-nodes are all 0, determining that the value of the coding block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes is 1.

In a second aspect, embodiments of the present invention provide a video decoding method, which is performed by a codec device or a codec apparatus. The method comprises the following steps: acquiring a coding block identification (Coding Block Flag) of a current transformation tree node; when the current transformation tree node is divided into N transformation tree sub-nodes, acquiring coding block identifiers (Coding Block Flag) of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes, wherein N is an integer greater than 1; determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes and the value of the coding block identifier of the current transform tree node; and acquiring the decoded image block indicated by the current transformation tree node according to the coding block identifiers of the N transformation tree child nodes.

The transform tree node may be a Coding Unit (CU) or a sub-block of a coding unit.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the N is 2,3 or 4

With reference to the second aspect or the first implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the N-1 transform tree sub-nodes are first N-1 transform tree sub-nodes in the N transform tree sub-nodes.

With reference to the second aspect, in a first implementation manner of the second aspect or a second implementation manner of the second aspect, the N transform tree child nodes are N Transform Units (TUs).

With reference to the second aspect or any implementation manner of the second aspect, in a fourth possible implementation manner of the second aspect, the determining, according to the value of the coding block identifier of the N-1 transform tree child nodes and the value of the coding block identifier of the current transform tree node, the value of the coding block identifier (Coding Block Flag) of one of the N transform tree child nodes except for the N-1 transform tree child nodes includes: determining whether a value of a coding block identification of the current transform tree node indicates that a chroma component transform block of the current transform tree node contains non-zero transform coefficients, and whether a value of a coding block identification of the N-1 transform tree sub-nodes indicates that a chroma component transform block of the N-1 transform tree sub-node does not contain non-zero transform coefficients; when the value of the coding block identification of the current transform tree node indicates that the chroma component transform block of the current transform tree node contains non-zero transform coefficients and the value of the coding block identification of the N-1 transform tree sub-node indicates that the chroma component transform block of the N-1 transform tree sub-node does not contain non-zero transform coefficients, determining that the value of the coding block identification of the one transform tree sub-node indicates that the chroma component transform block of the one transform tree sub-node contains non-zero transform coefficients.

With reference to the fourth implementation manner of the second aspect, in a fifth possible implementation manner of the second aspect, the coded block identifier of the chrominance component includes a coded block identifier of a blue chrominance component or a coded block identifier of a red chrominance component, and correspondingly, the chrominance component transform block includes a blue chrominance component transform block or a red chrominance component transform block.

With reference to the second aspect or any implementation manner of the second aspect, in a sixth possible implementation manner of the second aspect, the coding block identifier is at least one of a coding block identifier of a luma component, a coding block identifier of a blue chroma component and a coding block identifier of a red chroma component, and the determining, according to the value of the coding block identifier of the N-1 transform tree sub-nodes and the value of the coding block identifier of the current transform tree node, a value of a coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes includes: determining whether a coded block identification of a blue chrominance component and a coded block identification of a red chrominance component of the current transform tree node indicate that neither a blue chrominance component transform block nor a red chrominance component block of the current transform tree node contain non-zero transform coefficients, and whether a value of a coded block identification of a luminance component of the N-1 transform tree child node indicates that a luminance component transform block of the N-1 transform tree child node does not contain non-zero transform coefficients; when the coded block identification of the blue chrominance component and the coded block identification of the red chrominance component of the current transform tree node indicate that neither the blue chrominance component transform block nor the red chrominance component of the current transform tree node contain non-zero transform coefficients, and the value of the coded block identification of the luminance component of the N-1 transform tree sub-node indicates that the luminance component transform block of the N-1 transform tree sub-node does not contain non-zero transform coefficients, determining that the value of the coded block identification of the luminance component of the one transform tree sub-node indicates that the luminance component transform block of the one transform tree sub-node contains non-zero transform coefficients.

With reference to the second aspect or any one of possible implementation manners of the second aspect, in a seventh possible implementation manner of the second aspect, the current transform tree node may include an encoding unit, and the obtaining the encoded block identifier of the current transform tree node includes: and acquiring the coding block identification of the coding unit, wherein the value of the coding block identification of the coding unit indicates that a coding unit grammar structure of the coding unit in the code stream to which the coding unit belongs has a transformation tree grammar structure.

With reference to the second aspect or any one of possible implementation manners of the second aspect, in an eighth possible implementation manner of the second aspect, the method may further include: and acquiring a coding block identifier of a coding unit corresponding to the current transformation tree node, wherein the value of the coding block identifier of the coding unit indicates that the coding unit has a transformation tree related grammar structure.

In a third aspect, embodiments of the present invention provide a video encoding method, which is performed by a codec device or a codec apparatus. The method comprises the following steps:

determining the value of coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in N transform tree sub-nodes of a current transform tree node, wherein N is an integer greater than 1;

Determining whether to encode the code stream to which the current transformation tree node belongs with the code block identifier (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes according to the value of the code block identifiers of the N-1 transformation tree sub-nodes;

under the condition that the code block identification (Coding Block Flag) of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-node is not coded into the code stream of the current transformation tree node, the code block identification (Coding Block Flag) of the N-1 transformation tree sub-node is coded into the code stream of the current transformation tree node, and the code stream of the code data which does not contain the code block identification or the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-node is obtained.

The coding block identifiers (Coding Block Flag) of the N-1 transform tree sub-nodes are coded into the code stream to which the current transform tree node belongs, which can be understood as coding the coding block identifiers of the N-1 transform tree sub-nodes.

In one implementation, the method may further include: under the condition that the code block identification (Coding Block Flag) of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is determined to be coded into the code stream of the current transformation tree node, the code block identification (Coding Block Flag) of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is determined to be coded into the code stream of the current transformation tree node.

With reference to the third aspect, in a first possible implementation manner of the third aspect, the method further includes:

determining a value of a coding block identification (coding block flag) of the current transform tree node;

correspondingly, the determining whether to encode the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into the code stream to which the current transform tree node belongs according to the value of the code block identifier of the N-1 transform tree sub-nodes includes:

determining whether to encode the code stream of the current transformation tree node with the code block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes and the code block identification (coding block flag) of the current transformation tree node.

With reference to the third aspect or the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, in a case of determining that the current transform tree node is divided into N transform tree sub-nodes, the determining a value of a coding block identifier (Coding Block Flag) of N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node is performed.

With reference to the third aspect or any one of the possible implementation manners of the third aspect, in a third possible implementation manner of the third aspect, the N is 2,3 or 4.

With reference to the third aspect or any one of possible implementation manners of the third aspect, in a fourth possible implementation manner of the third aspect, the N-1 transform tree sub-nodes are first N-1 transform tree sub-nodes in the N transform tree sub-nodes.

With reference to the third aspect or any one of possible implementation manners of the third aspect, in a fifth possible implementation manner of the third aspect, the N transform tree child nodes are N Transform Units (TUs).

With reference to the third aspect or any one of possible implementation manners of the third aspect, in a sixth possible implementation manner of the third aspect, the current transform tree node is a Coding Unit (CU).

With reference to the third aspect or any one of the possible implementation manners of the third aspect, in a seventh possible implementation manner of the third aspect, the determining whether to encode, according to the value of the encoded block identifier of the N-1 transform tree sub-nodes, the encoded block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into the bitstream to which the current transform tree node belongs may include: determining whether the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the coding blocks of the N-1 transform tree nodes contain non-zero transform coefficients, meaning that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is not encoded into the code stream to which the current transform tree node belongs, and the value of the coding block identification of the N-1 transform tree sub-nodes indicates that the coding block of at least one of the N-1 transform tree nodes contains non-zero transform coefficients, meaning that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is encoded into the code stream to which the current transform tree node belongs.

With reference to the third aspect or any one of the possible implementation manners of the third aspect, in a seventh possible implementation manner of the third aspect, the determining whether to encode, according to the value of the encoded block identifier of the N-1 transform tree sub-nodes, the encoded block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into the bitstream to which the current transform tree node belongs may include: determining whether the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0, wherein the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0 means that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not coded into the code stream to which the current transform tree node belongs, and at least one of the values of the coding block identifications of the N-1 transform tree sub-nodes is 1 means that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is coded into the code stream to which the current transform tree node belongs.

In a fourth aspect, embodiments of the present invention provide a video encoding method, which is performed by a codec device or a codec apparatus. The method comprises the following steps:

Determining a value of a coded block identification (Coding Block Flag) of a current transform tree node;

determining the value of coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in N transform tree sub-nodes when the current transform tree node is divided into N transform tree sub-nodes, wherein N is an integer greater than 1;

determining whether to encode the code stream of the current transformation tree node with the code block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes and the code block identification value of the current transformation tree node;

With reference to the fourth aspect, in a first possible implementation manner of the fourth aspect, the N is 2,3 or 4

With reference to the fourth aspect or the first implementation manner of the fourth aspect, in a second possible implementation manner of the fourth aspect, the N-1 transform tree sub-nodes are first N-1 transform tree sub-nodes in the N transform tree sub-nodes.

With reference to the fourth aspect, or the first implementation manner of the fourth aspect or the second implementation manner of the fourth aspect, the N transform tree child nodes are N Transform Units (TUs).

In a fifth aspect, an embodiment of the present invention provides a video decoding apparatus, the apparatus comprising:

an obtaining unit, configured to obtain coding block identifiers (Coding Block Flag) of N-1 transform tree child nodes in N transform tree child nodes of a current transform tree node, where N is an integer greater than 1;

a determining unit configured to determine a value of a coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes, based on the values of coding block identifiers of the N-1 transform tree sub-nodes;

And the reconstruction unit is used for reconstructing the current transformation tree node according to the values of the coding block identifiers of the N transformation tree child nodes.

With reference to the fifth aspect, in a first possible implementation manner of the fifth aspect, the obtaining unit is further configured to:

acquiring a coding block flag (codingblock flag) of the current transformation tree node;

correspondingly, the determining unit is used for:

With reference to the fifth aspect, in a second possible implementation manner of the fifth aspect, the determining unit is configured to:

With reference to the fifth aspect, in a second possible implementation manner of the fifth aspect, the obtaining unit is configured to obtain, in a case where it is determined that the current transform tree node is divided into N transform tree sub-nodes, a coding block identification (Coding Block Flag) of N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node.

With reference to the fifth aspect or any one of possible implementation manners of the fifth aspect, in a third possible implementation manner of the fifth aspect, the N is 2,3 or 4.

With reference to the fifth aspect or any one of possible implementation manners of the fifth aspect, in a fourth possible implementation manner of the fifth aspect, the N-1 transform tree child nodes are first N-1 transform tree child nodes in the N transform tree child nodes.

With reference to the fifth aspect or any one of possible implementation manners of the fifth aspect, in a fifth possible implementation manner of the fifth aspect, the N transform tree child nodes are N Transform Units (TUs).

With reference to the fifth aspect or any one of possible implementation manners of the fifth aspect, in a sixth possible implementation manner of the fifth aspect, the current transform tree node is a Coding Unit (CU).

With reference to the fifth aspect or any one of possible implementation manners of the fifth aspect, in a seventh possible implementation manner of the fifth aspect, the determining unit is configured to: determining whether values of coding block identifications of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients; in the case that it is determined that the values of the code block identifications of the N-1 transform tree sub-nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, determining that the values of the code block identifications (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicate that one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contain non-zero transform coefficients.

The method according to the first aspect of the invention may be performed by an apparatus according to the fifth aspect of the invention. The functionality of the apparatus according to the fifth aspect of the invention and its different implementations depend on other features and implementations of the method according to the first aspect of the invention.

In a sixth aspect, an embodiment of the present invention provides a video decoding apparatus, the apparatus including:

An acquisition unit for acquiring a coding block identification (Coding Block Flag) of a current transform tree node;

the obtaining unit is further configured to obtain, when the current transform tree node is divided into N transform tree sub-nodes, coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in the N transform tree sub-nodes, where N is an integer greater than 1;

a determining unit, configured to determine a value of a coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-node and the value of the coding block identifier of the current transform tree node;

and the reconstruction unit is used for acquiring the decoded image block indicated by the current transformation tree node according to the coding block identifiers of the N transformation tree child nodes.

With reference to the sixth aspect or any one of possible implementation manners of the sixth aspect, in a third possible implementation manner of the sixth aspect, the N is 2,3 or 4.

With reference to the sixth aspect or any one of the possible implementation manners of the sixth aspect, in a fourth possible implementation manner of the sixth aspect, the N-1 transform tree child nodes are first N-1 transform tree child nodes in the N transform tree child nodes.

With reference to the sixth aspect or any one of possible implementation manners of the sixth aspect, in a fifth possible implementation manner of the sixth aspect, the N transform tree child nodes are N transform units (units, TUs).

With reference to the sixth aspect or any one of possible implementation manners of the sixth aspect, in a sixth possible implementation manner of the sixth aspect, the current transform tree node is a Coding Unit (CU).

The method according to the second aspect of the invention may be performed by an apparatus according to the sixth aspect of the invention. The functionality of the apparatus according to the sixth aspect of the invention and its different implementations depend on other features and implementations of the method according to the second aspect of the invention.

In a seventh aspect, an embodiment of the present invention provides a video encoding apparatus, the apparatus including:

a determining unit, configured to determine values of coding block identifiers (Coding Block Flag) of N-1 transform tree child nodes among N transform tree child nodes of the current transform tree node, where N is an integer greater than 1;

the determining unit is further configured to determine, according to the values of the coding block identifiers of the N-1 transform tree sub-nodes, whether to encode the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs;

An encoding unit for identifying (Coding Block Flag) an encoding block of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes in determining to use the encoding block

Under the condition that the code stream of the current transformation tree node is not coded, coding block identifiers (Coding Block Flag) of the N-1 transformation tree sub-nodes are coded into the code stream of the current transformation tree node, so that the code stream of the coded data which does not contain the coding block identifiers or the coding block identifiers of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes is obtained.

With reference to the seventh aspect, in a first possible implementation manner of the seventh aspect, the determining unit is further configured to:

correspondingly, the determining unit is used for:

With reference to the seventh aspect or the first possible implementation manner of the seventh aspect, in a second possible implementation manner of the seventh aspect, the determining unit is configured to: in the case that the current transform tree node is determined to be divided into N transform tree sub-nodes, a value of a coded block identification (Coding Block Flag) of N-1 of the N transform tree sub-nodes of the current transform tree node is determined.

With reference to the seventh aspect or any one of possible implementation manners of the seventh aspect, in a third possible implementation manner of the seventh aspect, the N is 2,3 or 4.

With reference to the seventh aspect or any one of possible implementation manners of the seventh aspect, in a fourth possible implementation manner of the seventh aspect, the N-1 transform tree child nodes are first N-1 transform tree child nodes in the N transform tree child nodes.

With reference to the seventh aspect or any one of possible implementation manners of the seventh aspect, in a fifth possible implementation manner of the seventh aspect, the N transform tree child nodes are N transform units (units, TUs).

With reference to the seventh aspect or any one of possible implementation manners of the seventh aspect, in a sixth possible implementation manner of the seventh aspect, the current transform tree node is a Coding Unit (CU).

The method according to the third aspect of the invention may be performed by an apparatus according to the seventh aspect of the invention. The functionality of the apparatus according to the seventh aspect of the invention and its different implementations depend on other features and implementations of the method according to the third aspect of the invention.

In an eighth aspect, an embodiment of the present invention provides a video encoding apparatus, the apparatus comprising:

a determining unit for determining a value of a coding block identification (Coding Block Flag) of a current transform tree node; determining the value of coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in N transform tree sub-nodes when the current transform tree node is divided into N transform tree sub-nodes, wherein N is an integer greater than 1; determining whether to encode the code stream of the current transformation tree node with the code block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes and the code block identification value of the current transformation tree node;

and the coding unit is used for coding the coding block identifiers (Coding Block Flag) of the N-1 transformation tree sub-nodes into the code stream of the current transformation tree node under the condition that the coding block identifiers (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-node are not coded into the code stream of the current transformation tree node, so as to obtain the code stream of the coding data which does not contain the coding block identifiers or the coding block identifiers of one transformation tree sub-node except the N-1 transformation tree sub-node in the N transformation tree sub-nodes.

With reference to the eighth aspect or any one of the possible implementation manners of the eighth aspect, in a third possible implementation manner of the eighth aspect, the N is 2,3 or 4.

With reference to the eighth aspect or any one of the possible implementation manners of the eighth aspect, in a fourth possible implementation manner of the eighth aspect, the N-1 transform tree child nodes are first N-1 transform tree child nodes in the N transform tree child nodes.

With reference to the eighth aspect or any one of the possible implementation manners of the eighth aspect, in a fifth possible implementation manner of the eighth aspect, the N transform tree child nodes are N Transform_units (TUs).

With reference to the eighth aspect or any one of the possible implementation manners of the eighth aspect, in a sixth possible implementation manner of the eighth aspect, the current transform tree node is a Coding Unit (CU).

The method according to the fourth aspect of the invention may be performed by an apparatus according to the eighth aspect of the invention. The functionality of the apparatus according to the eighth aspect of the invention and its different implementations depend on other features and implementations of the method according to the fourth aspect of the invention.

In a ninth aspect, the present invention is directed to an apparatus for decoding a video stream, comprising a processor and a memory. The memory stores instructions that cause the processor to perform the method according to the first aspect.

In a tenth aspect, the present invention is directed to an apparatus for encoding a video stream, comprising a processor and a memory. The memory stores instructions that cause the processor to perform a method according to the second aspect.

In an eleventh aspect, the present invention is directed to an apparatus for decoding a video stream, comprising a processor and a memory. The memory stores instructions that cause the processor to perform a method according to the third aspect.

In a twelfth aspect, the invention is directed to an apparatus for encoding a video stream, comprising a processor and a memory. The memory stores instructions that cause the processor to perform a method according to the fourth aspect.

In a thirteenth aspect, a computer-readable storage medium is presented having instructions stored thereon that, when executed, cause one or more processors to encode video data. The instructions cause the one or more processors to perform the method according to the first or second or third or fourth aspect or any possible embodiment of the first or second or third or fourth aspect.

In a fourteenth aspect, the present invention relates to a computer program comprising program code which, when run on a computer, performs a method according to the first or second or third or fourth aspect or any possible embodiment of the first or second or third or fourth aspect.

In a fifteenth aspect, an embodiment of the present application provides an apparatus for decoding video data, the apparatus comprising:

a memory for storing video data in the form of a code stream;

a video decoder for decoding decoded video data from a bitstream according to the first or second aspect or any possible embodiment of the first or second aspect.

In a sixteenth aspect, an embodiment of the present application provides an apparatus for encoding video data, the apparatus comprising:

a memory for storing video data, the video data comprising one or more image blocks;

a video encoder for generating a bitstream of said video data according to the first or second aspect or any possible embodiment of the first or second aspect.

In a seventeenth aspect, an embodiment of the present application provides a video code stream, where the code stream includes encoded data of N transform tree sub-nodes of a current transform tree node, the encoded data of N transform tree sub-nodes includes encoded block identifiers or encoded block identifiers of N-1 transform tree sub-nodes, the encoded data of N transform tree sub-nodes does not include encoded data of encoded block identifiers or encoded block identifiers of one transform tree sub-node other than the N-1 transform tree sub-nodes in the N transform tree sub-nodes, and N is an integer greater than 1.

Wherein the value of the coding block identification of the N-1 transform tree child nodes may indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients.

Wherein, the values of the code block identifications of the N-1 transform tree child nodes can be 0.

It should be understood that the second to seventeenth aspects of the present application are consistent with the technical solutions of the first aspect of the present application, and the advantages obtained by each aspect and the corresponding possible embodiments are similar, and are not repeated.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Drawings

In order to more clearly describe the embodiments of the present application or the technical solutions in the background art, the following description will describe the drawings that are required to be used in the embodiments of the present application or the background art.

FIG. 1A is a block diagram of an example of a video encoding and decoding system 10 for implementing an embodiment of the application;

FIG. 1B is a block diagram of an example of a video coding system 40 for implementing an embodiment of the application;

FIG. 2 is a block diagram of an example structure of an encoder 20 for implementing an embodiment of the present application;

FIG. 3 is a block diagram of an example architecture of a decoder 30 for implementing an embodiment of the present application;

Fig. 4 is a block diagram of an example of a video coding apparatus 400 for implementing an embodiment of the application;

FIG. 5 is a block diagram of another example encoding or decoding device for implementing an embodiment of the present application;

FIG. 6 is a schematic block diagram of one block partitioning approach for implementing an embodiment of the present application;

FIG. 7 is a schematic block diagram of another block partitioning approach for implementing an embodiment of the present application;

FIG. 8 is a flow chart of a video decoding method for implementing an embodiment of the present application;

fig. 9 is a flowchart of a video encoding method for implementing an embodiment of the present application;

fig. 10 is a schematic block diagram of a video decoding apparatus for implementing an embodiment of the present application;

fig. 11 is a schematic block diagram of a video encoding apparatus for implementing an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. In the following description, reference is made to the accompanying drawings which form a part hereof and which show by way of illustration specific aspects in which embodiments of the application may be practiced. It is to be understood that embodiments of the application may be used in other aspects and may include structural or logical changes not depicted in the drawings. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present application is defined by the appended claims. For example, it should be understood that the disclosure in connection with the described methods may be equally applicable to a corresponding apparatus or system for performing the methods, and vice versa. For example, if one or more specific method steps are described, the corresponding apparatus may comprise one or more units, such as functional units, to perform the one or more described method steps (e.g., one unit performing one or more steps, or multiple units each performing one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, if a specific apparatus is described based on one or more units such as a functional unit, for example, the corresponding method may include one step to perform the functionality of the one or more units (e.g., one step to perform the functionality of the one or more units, or multiple steps each to perform the functionality of one or more units, even if such one or more steps are not explicitly described or illustrated in the figures). Further, it is to be understood that features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless explicitly stated otherwise.

The technical scheme related to the embodiment of the invention can be applied to the existing video coding standards (such as H.264, HEVC and the like) and future video coding standards (such as H.266). The terminology used in the description of the embodiments of the invention herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting of the invention. Some concepts that may be related to embodiments of the present invention are briefly described below.

Video coding generally refers to processing a sequence of pictures that form a video or video sequence. In the field of video coding, the terms "picture", "frame" or "image" may be used as synonyms. Video encoding as used herein refers to video encoding or video decoding. Video encoding is performed on the source side, typically including processing (e.g., by compression) the original video picture to reduce the amount of data required to represent the video picture, thereby more efficiently storing and/or transmitting. Video decoding is performed on the destination side, typically involving inverse processing with respect to the encoder to reconstruct the video pictures. The embodiment relates to video picture "encoding" is understood to relate to "encoding" or "decoding" of a video sequence. The combination of the encoding portion and the decoding portion is also called codec (encoding and decoding).

A video sequence comprises a series of pictures (pictures) which are further divided into slices (slices) which are further divided into blocks (blocks). Video coding performs coding processing in units of blocks, and in some new video coding standards, the concept of blocks is further extended. For example, in the h.264 standard, there are Macro Blocks (MBs), which can be further divided into a plurality of prediction blocks (partition) that can be used for predictive coding. In the high performance video coding (high efficiency video coding, HEVC) standard, basic concepts such as a Coding Unit (CU), a Prediction Unit (PU), and a Transform Unit (TU) are adopted, and various block units are functionally divided and described by using a brand new tree-based structure. A CU is a basic unit that divides and encodes an encoded image. Similar tree structures exist for PUs and TUs, which may correspond to prediction blocks, being the basic unit of predictive coding. The CU is further divided into a plurality of PUs according to a division pattern. The CU may be further divided into a plurality of TUs according to a partition mode, and a TU may correspond to a transform block, which is a basic unit for transforming a prediction residual. However, whether CU, PU or TU, essentially belongs to the concept of blocks (or picture blocks).

In HEVC, for example, CTUs are split into multiple CUs by using a quadtree structure denoted as coding tree. A decision is made at the CU level whether to encode a picture region using inter-picture (temporal) or intra-picture (spatial) prediction. Each CU may be further split into one, two, or four PUs depending on the PU split type. The same prediction process is applied within one PU and the relevant information is transmitted to the decoder on a PU basis. After the residual block is obtained by applying the prediction process based on the PU split type, the CU may be partitioned into Transform Units (TUs) according to other quadtree structures similar to the coding tree for the CU. In a recent development of video compression techniques, the encoded blocks are partitioned using quadtree, trigeminal tree and binary tree partition frames, and the resulting CU may have a square or rectangular shape.

Herein, for convenience of description and understanding, an image block to be encoded in a current encoded image may be referred to as a current block, for example, in encoding, a block currently being encoded; in decoding, a block currently being decoded is referred to. A decoded image block in a reference image used for predicting a current block is referred to as a reference block, i.e. a reference block is a block providing a reference signal for the current block, wherein the reference signal represents pixel values within the image block. A block in the reference picture that provides a prediction signal for the current block may be referred to as a prediction block, where the prediction signal represents pixel values or sample signals within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found, which will provide prediction for the current block, which is referred to as the prediction block.

In the case of lossless video coding, the original video picture may be reconstructed, i.e., the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, the amount of data needed to represent a video picture is reduced by performing further compression, e.g. quantization, whereas the decoder side cannot reconstruct the video picture completely, i.e. the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

Several video coding standards of h.261 belong to the "lossy hybrid video codec" (i.e. spatial and temporal prediction in the sample domain is combined with 2D transform coding in the transform domain for applying quantization). Each picture of a video sequence is typically partitioned into non-overlapping sets of blocks, typically encoded at the block level. In other words, the encoder side typically processes, i.e. encodes, video at the block (video block) level, e.g. generates a prediction block by spatial (intra-picture) prediction and temporal (inter-picture) prediction, subtracts the prediction block from the current block (currently processed or to-be-processed block) to obtain a residual block, transforms the residual block in the transform domain and quantizes the residual block to reduce the amount of data to be transmitted (compressed), while the decoder side applies the inverse processing part of the relative encoder to the encoded or compressed block to reconstruct the current block for representation. In addition, the encoder replicates the decoder processing loop so that the encoder and decoder generate the same predictions (e.g., intra-prediction and inter-prediction) and/or reconstructions for processing, i.e., encoding, the subsequent blocks.

The system architecture to which the embodiments of the present invention are applied is described below. Referring to fig. 1A, fig. 1A schematically illustrates a block diagram of a video encoding and decoding system 10 to which embodiments of the present invention are applied. As shown in fig. 1A, video encoding and decoding system 10 may include a source device 12 and a destination device 14, source device 12 generating encoded video data, and thus source device 12 may be referred to as a video encoding apparatus. Destination device 14 may decode encoded video data generated by source device 12, and thus destination device 14 may be referred to as a video decoding apparatus. Various implementations of source apparatus 12, destination apparatus 14, or both may include one or more processors and memory coupled to the one or more processors. The memory may include, but is not limited to RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures that can be accessed by a computer, as described herein. The source device 12 and the destination device 14 may include a variety of devices including desktop computers, mobile computing devices, notebook (e.g., laptop) computers, tablet computers, set-top boxes, telephone handsets such as so-called "smart" phones, televisions, cameras, display devices, digital media players, video game consoles, vehicle mount computers, wireless communication devices, or the like.

Although fig. 1A depicts source device 12 and destination device 14 as separate devices, device embodiments may also include the functionality of both source device 12 and destination device 14, or both, i.e., source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, the source device 12 or corresponding functionality and the destination 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.

A communication connection may be made between source device 12 and destination device 14 via link 13, and destination device 14 may receive encoded video data from source device 12 via link 13. Link 13 may include one or more media or devices capable of moving encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real-time. In this example, source apparatus 12 may modulate the encoded video data according to a communication standard, such as a wireless communication protocol, and may transmit the modulated video data to destination apparatus 14. The one or more communication media may include wireless and/or wired communication media such as a Radio Frequency (RF) spectrum or one or more physical transmission lines. The one or more communication media may form part of a packet-based network, such as a local area network, a wide area network, or a global network (e.g., the internet). The one or more communication media may include routers, switches, base stations, or other equipment that facilitate communication from source apparatus 12 to destination apparatus 14.

Source device 12 includes an encoder 20 and, alternatively, source device 12 may also include a picture source 16, a picture preprocessor 18, and a communication interface 22. In a specific implementation, the encoder 20, the picture source 16, the picture preprocessor 18, and the communication interface 22 may be hardware components in the source device 12 or may be software programs in the source device 12. The descriptions are as follows:

the picture source 16 may include or be any type of picture capture device for capturing, for example, real world pictures, and/or any type of picture or comment (for screen content encoding, some text on the screen is also considered part of the picture or image to be encoded), for example, a computer graphics processor for generating computer animated pictures, or any type of device for capturing and/or providing real world pictures, computer animated pictures (e.g., screen content, virtual Reality (VR) pictures), and/or any combination thereof (e.g., live (augmented reality, AR) pictures). Picture source 16 may be a camera for capturing pictures or a memory for storing pictures, picture source 16 may also include any type of (internal or external) interface for storing previously captured or generated pictures and/or for capturing or receiving pictures. When picture source 16 is a camera, picture source 16 may be, for example, an integrated camera, either local or integrated in the source device; when picture source 16 is memory, picture source 16 may be local or integrated memory integrated in the source device, for example. When the picture source 16 comprises an interface, the interface may for example be an external interface receiving pictures from an external video source, for example an external picture capturing device, such as a camera, an external memory or an external picture generating device, for example an external computer graphics processor, a computer or a server. The interface may be any kind of interface according to any proprietary or standardized interface protocol, e.g. a wired or wireless interface, an optical interface.

Wherein a picture can be regarded as a two-dimensional array or matrix of pixel elements. The pixels in the array may also be referred to as sampling points. The number of sampling points of the array or picture in the horizontal and vertical directions (or axes) defines the size and/or resolution of the picture. To represent color, three color components are typically employed, i.e., a picture may be represented as or contain three sample arrays. For example, in RBG format or color space, the picture includes corresponding red, green, and blue sample arrays. However, in video coding, each pixel is typically represented in a luminance/chrominance format or color space, e.g., for a picture in YUV format, comprising a luminance component indicated by Y (which may sometimes also be indicated by L) and two chrominance components indicated by U and V. The luminance (luma) component Y represents the luminance or grayscale level intensity (e.g., the same in a grayscale picture), while the two chrominance (chroma) components U and V represent the chrominance or color information components. Accordingly, a picture in YUV format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (U and V). Pictures in RGB format may be converted or transformed into YUV format and vice versa, a process also known as color transformation or conversion. If the picture is black and white, the picture may include only an array of luma samples. In the embodiment of the present invention, the picture transmitted from the picture source 16 to the picture processor may also be referred to as the original picture data 17.

A picture preprocessor 18 for receiving the original picture data 17 and performing preprocessing on the original picture data 17 to obtain a preprocessed picture 19 or preprocessed picture data 19. For example, the preprocessing performed by the picture preprocessor 18 may include truing, color format conversion (e.g., from RGB format to YUV format), toning, or denoising.

Encoder 20 (or video encoder 20) receives pre-processed picture data 19, and processes pre-processed picture data 19 using an associated prediction mode (e.g., a prediction mode in various embodiments herein) to provide encoded picture data 21 (details of the structure of encoder 20 will be described further below based on fig. 2 or fig. 4 or fig. 5). In some embodiments, encoder 20 may be configured to perform various embodiments described below to implement the application of the chroma block prediction method described in the present invention on the encoding side.

Communication interface 22 may be used to receive encoded picture data 21 and may transmit encoded picture data 21 over link 13 to destination device 14 or any other device (e.g., memory) for storage or direct reconstruction, which may be any device for decoding or storage. Communication interface 22 may be used, for example, to encapsulate encoded picture data 21 into a suitable format, such as a data packet, for transmission over link 13.

Destination device 14 includes a decoder 30, and alternatively destination device 14 may also include a communication interface 28, a picture post-processor 32, and a display device 34. The descriptions are as follows:

communication interface 28 may be used to receive encoded picture data 21 from source device 12 or any other source, such as a storage device, such as an encoded picture data storage device. The communication interface 28 may be used to transmit or receive encoded picture data 21 via a link 13 between the source device 12 and the destination device 14, such as a direct wired or wireless connection, or via any type of network, such as a wired or wireless network or any combination thereof, or any type of private and public networks, or any combination thereof. Communication interface 28 may, for example, be used to decapsulate data packets transmitted by communication interface 22 to obtain encoded picture data 21.

Both communication interface 28 and communication interface 22 may be configured as unidirectional communication interfaces or bidirectional communication interfaces and may be used, for example, to send and receive messages to establish connections, to acknowledge and to exchange any other information related to the communication link and/or to the transmission of data, for example, encoded picture data transmissions.

Decoder 30 (or referred to as decoder 30) for receiving encoded picture data 21 and providing decoded picture data 31 or decoded picture 31 (details of the structure of decoder 30 will be described below further based on fig. 3 or fig. 4 or fig. 5). In some embodiments, decoder 30 may be configured to perform various embodiments described below to implement the application of the chroma block prediction method described in the present invention on the decoding side.

A picture post-processor 32 for performing post-processing on the decoded picture data 31 (also referred to as reconstructed slice data) to obtain post-processed picture data 33. The post-processing performed by the picture post-processor 32 may include: color format conversion (e.g., from YUV format to RGB format), toning, truing, or resampling, or any other process, may also be used to transmit post-processed picture data 33 to display device 34.

A display device 34 for receiving the post-processed picture data 33 for displaying pictures to, for example, a user or viewer. The display device 34 may be or include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor. For example, the display may include a liquid crystal display (liquid crystal display, LCD), an organic light emitting diode (organic light emitting diode, OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (liquid crystal on silicon, LCoS), a digital light processor (digital light processor, DLP), or any other type of display.

It will be apparent to those skilled in the art from this description that the functionality of the different units or the existence and (exact) division of the functionality of the source device 12 and/or destination device 14 shown in fig. 1A may vary depending on the actual device and application. Source device 12 and destination device 14 may comprise any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smart phone, tablet or tablet computer, video camera, desktop computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (e.g., content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not use or use any type of operating system.

Encoder 20 and decoder 30 may each be implemented as any of a variety of suitable circuits, such as, for example, one or more microprocessors, digital signal processors (digital signal processor, DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware or any combinations thereof. If the techniques are implemented in part in software, an apparatus may store instructions of the software in a suitable non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Any of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be considered one or more processors.

In some cases, the video encoding and decoding system 10 shown in fig. 1A is merely an example, and the techniques of this disclosure may be applied to video encoding settings (e.g., video encoding or video decoding) that do not necessarily involve any data communication between encoding and decoding devices. In other examples, the data may be retrieved from local memory, streamed over a network, and the like. The video encoding device may encode and store data to the memory and/or the video decoding device may retrieve and decode data from the memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but instead only encode data to memory and/or retrieve data from memory and decode data.

Referring to fig. 1B, fig. 1B is an illustration of an example of a video coding system 40 including encoder 20 of fig. 2 and/or decoder 30 of fig. 3, according to an example embodiment. Video coding system 40 may implement a combination of the various techniques of embodiments of the present invention. In the illustrated implementation, video coding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video codec implemented by logic circuits 47 of a processing unit 46), an antenna 42, one or more processors 43, one or more memories 44, and/or a display device 45.

As shown in fig. 1B, the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other. As discussed, although video coding system 40 is depicted with encoder 20 and decoder 30, in different examples, video coding system 40 may include only encoder 20 or only decoder 30.

In some examples, antenna 42 may be used to transmit or receive an encoded bitstream of video data. Additionally, in some examples, display device 45 may be used to present video data. In some examples, logic 47 may be implemented by processing unit 46. The processing unit 46 may comprise application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, or the like. The video coding system 40 may also include an optional processor 43, which optional processor 43 may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general purpose processor, or the like. In some examples, logic 47 may be implemented in hardware, such as video encoding dedicated hardware, processor 43 may be implemented in general purpose software, an operating system, or the like. In addition, the memory 44 may be any type of memory, such as volatile memory (e.g., static random access memory (Static Random Access Memory, SRAM), dynamic random access memory (Dynamic Random Access Memory, DRAM), etc.) or non-volatile memory (e.g., flash memory, etc.), and the like. In a non-limiting example, the memory 44 may be implemented by an overspeed cache. In some examples, logic circuitry 47 may access memory 44 (e.g., for implementing an image buffer). In other examples, logic 47 and/or processing unit 46 may include memory (e.g., a cache, etc.) for implementing an image buffer, etc.

In some examples, encoder 20 implemented by logic circuitry may include an image buffer (e.g., implemented by processing unit 46 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include encoder 20 implemented by logic circuitry 47 to implement the various modules discussed with reference to fig. 2 and/or any other encoder system or subsystem described herein. Logic circuitry may be used to perform various operations discussed herein.

In some examples, decoder 30 may be implemented in a similar manner by logic circuit 47 to implement the various modules discussed with reference to decoder 30 of fig. 3 and/or any other decoder system or subsystem described herein. In some examples, decoder 30 implemented by logic circuitry may include an image buffer (implemented by processing unit 2820 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include decoder 30 implemented by logic circuit 47 to implement the various modules discussed with reference to fig. 3 and/or any other decoder system or subsystem described herein.

In some examples, antenna 42 may be used to receive an encoded bitstream of video data. As discussed, the encoded bitstream may include data related to the encoded video frame, indicators, index values, mode selection data, etc., discussed herein, such as data related to the encoded partitions (e.g., transform coefficients or quantized transform coefficients, optional indicators (as discussed), and/or data defining the encoded partitions). Video coding system 40 may also include a decoder 30 coupled to antenna 42 and used to decode the encoded bitstream. The display device 45 is used to present video frames.

It should be understood that decoder 30 may be used to perform the reverse process for the example described with reference to encoder 20 in embodiments of the present invention. Regarding signaling syntax elements, decoder 30 may be configured to receive and parse such syntax elements and decode the associated video data accordingly. In some examples, encoder 20 may entropy encode the syntax elements into an encoded video bitstream. In such examples, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.

It should be noted that, the video decoding method described in the embodiment of the present invention is mainly used in the inter-frame prediction process, where the process exists in both the encoder 20 and the decoder 30, and the encoder 20 and the decoder 30 in the embodiment of the present invention may be, for example, a codec corresponding to a video standard protocol such as h.263, h.264, HEVV, MPEG-2, MPEG-4, VP8, VP9, or a next-generation video standard protocol (such as h.266, etc.).

Referring to fig. 2, fig. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the invention. In the example of fig. 2, encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter unit 220, a decoded picture buffer (decoded picture buffer, DPB) 230, a prediction processing unit 260, and an entropy encoding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The 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.

For example, the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260 and the entropy encoding unit 270 form a forward signal path of the encoder 20, whereas for example the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (decoded picture buffer, DPB) 230, the prediction processing unit 260 form a backward signal path of the encoder, wherein the backward signal path of the encoder corresponds to the signal path of the decoder (see decoder 30 in fig. 3).

Encoder 20 receives picture 201 or an image block 203 of picture 201, e.g., a picture in a sequence of pictures forming a video or video sequence, through, e.g., input 202. Image block 203 may also be referred to as a current picture block or a picture block to be encoded, and picture 201 may be referred to as a current picture or a picture to be encoded (especially when distinguishing the current picture from other pictures in video encoding, such as previously encoded and/or decoded pictures in the same video sequence, i.e., a video sequence that also includes the current picture).

An embodiment of encoder 20 may comprise a partitioning unit (not shown in fig. 2) for partitioning picture 201 into a plurality of blocks, e.g. image blocks 203, typically into a plurality of non-overlapping blocks. The segmentation unit may be used to use the same block size for all pictures in the video sequence and a corresponding grid defining the block size, or to alter the block size between pictures or subsets or groups of pictures and to segment each picture into corresponding blocks.

In one example, prediction processing unit 260 of encoder 20 may be used to perform any combination of the above-described partitioning techniques.

Like picture 201, image block 203 is also or may be considered as a two-dimensional array or matrix of sampling points having sampling values, albeit of smaller size than picture 201. In other words, the image block 203 may comprise, for example, one sampling array (e.g., a luminance array in the case of a black-and-white picture 201) or three sampling arrays (e.g., one luminance array and two chrominance arrays in the case of a color picture) or any other number and/or class of arrays depending on the color format applied. The number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.

The encoder 20 as shown in fig. 2 is used for encoding a picture 201 block by block, for example, performing encoding and prediction for each image block 203.

The residual calculation unit 204 is configured to calculate a residual block 205 based on the picture image block 203 and the prediction block 265 (further details of the prediction block 265 are provided below), for example, by subtracting sample values of the prediction block 265 from sample values of the picture image block 203 on a sample-by-sample (pixel-by-pixel) basis to obtain the residual block 205 in a sample domain.

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

The transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transforms specified for HEVC/H.265. Such integer approximations are typically scaled by some factor compared to the orthogonal DCT transform. To maintain the norms of the forward and inverse transformed processed residual blocks, an additional scaling factor is applied as part of the transformation process. The scaling factor is typically selected based on certain constraints, e.g., the scaling factor is a tradeoff between power of 2, bit depth of transform coefficients, accuracy, and implementation cost for shift operations, etc. For example, a specific scaling factor is specified for inverse transformation by, for example, the inverse transformation processing unit 212 on the decoder 30 side (and for corresponding inverse transformation by, for example, the inverse transformation processing unit 212 on the encoder 20 side), and accordingly, a corresponding scaling factor may be specified for positive transformation by the transformation processing unit 206 on the encoder 20 side.

The quantization unit 208 is for quantizing the transform coefficients 207, for example by applying scalar quantization or vector quantization, to obtain quantized transform coefficients 209. The quantized transform coefficients 209 may also be referred to as quantized residual coefficients 209. The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m. The quantization level may be modified by adjusting quantization parameters (quantization parameter, QP). For example, for scalar quantization, different scales 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 appropriate quantization step size may be indicated by a quantization parameter (quantization parameter, QP). For example, the quantization parameter may be an index of a predefined set of suitable quantization steps. For example, smaller quantization parameters may correspond to fine quantization (smaller quantization step size) and larger quantization parameters may correspond to coarse quantization (larger quantization step size) and vice versa. Quantization may involve division by a quantization step size and corresponding quantization or inverse quantization, e.g., performed by inverse quantization 210, or may involve multiplication by a quantization step size. Embodiments according to some standards, such as HEVC, may use quantization parameters to determine quantization step sizes. In general, the quantization step size may be calculated based on quantization parameters using a fixed-point approximation of an equation that includes division. Additional scaling factors may be introduced for quantization and inverse quantization to recover norms of residual blocks that may be modified due to the scale used in the fixed point approximation of the equation for quantization step size and quantization parameters. In one example implementation, the inverse transform and the inverse quantized scale may be combined. Alternatively, a custom quantization table may be used and signaled from the encoder to the decoder, e.g., in a bitstream. Quantization is a lossy operation, where the larger the quantization step size, the larger the loss.

The inverse quantization unit 210 is configured to apply inverse quantization of the quantization unit 208 on the quantized coefficients to obtain inverse quantized coefficients 211, e.g., apply an inverse quantization scheme of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211 may also be referred to as dequantized residual coefficients 211, correspond to the transform coefficients 207, although the losses due to quantization are typically different from the transform coefficients.

The inverse transform processing unit 212 is configured to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (discrete cosine transform, DCT) or an inverse discrete sine transform (discrete sine transform, DST), to obtain an inverse transform block 213 in the sample domain. The inverse transform block 213 may also be referred to as an inverse transformed inverse quantized block 213 or an inverse transformed residual block 213.

A reconstruction unit 214 (e.g., a summer 214) is used to add the inverse transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, e.g., to add sample values of the reconstructed residual block 213 to sample values of the prediction block 265.

Optionally, a buffer unit 216, e.g. a line buffer 216 (or simply "buffer" 216), is used to buffer or store the reconstructed block 215 and the corresponding sample values for e.g. intra prediction. In other embodiments, the encoder may be configured to use the unfiltered reconstructed block and/or the corresponding sample values stored in the buffer unit 216 for any kind of estimation and/or prediction, such as intra prediction.

For example, embodiments of encoder 20 may be configured such that buffer unit 216 is used not only to store reconstructed blocks 215 for intra prediction 254, but also for loop filter unit 220 (not shown in fig. 2), and/or such that buffer unit 216 and decoded picture buffer unit 230 form one buffer, for example. Other embodiments may be used to use the filtered block 221 and/or blocks or samples (neither shown in fig. 2) from the decoded picture buffer 230 as an input or basis for the intra prediction 254.

The loop filter unit 220 (or simply "loop filter" 220) is used to filter the reconstructed block 215 to obtain a filtered block 221, which facilitates pixel transitions or improves video quality. Loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, adaptive loop filters (adaptive loop filter, ALF), or sharpening or smoothing filters, or collaborative filters. Although loop filter unit 220 is shown in fig. 2 as an in-loop filter, in other configurations loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as a filtered reconstructed block 221. Decoded picture buffer 230 may store the reconstructed encoded block after loop filter unit 220 performs a filtering operation on the reconstructed encoded block.

Embodiments of encoder 20 (and correspondingly loop filter unit 220) may be configured to output loop filter parameters (e.g., sample adaptive offset information), e.g., directly or after entropy encoding by entropy encoding unit 270 or any other entropy encoding unit, e.g., such that decoder 30 may receive and apply the same loop filter parameters for decoding.

Decoded picture buffer (decoded picture buffer, DPB) 230 may be a reference picture memory that stores reference picture data for use by encoder 20 in encoding video data. DPB 230 may be formed of any of a variety of memory devices, such as dynamic random access memory (dynamic random access memory, DRAM) (including Synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM)), or other types of memory devices. DPB 230 and buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, a decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the filtered block 221. The decoded picture buffer 230 may further be used to store the same current picture or other previously filtered blocks, e.g., previously reconstructed and filtered blocks 221, of different pictures, e.g., previously reconstructed pictures, and may provide complete previously reconstructed, i.e., decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), e.g., for inter prediction. In a certain example, if the reconstructed block 215 is reconstructed without in-loop filtering, the decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the reconstructed block 215.

The prediction processing unit 260, also referred to as block prediction processing unit 260, is adapted to receive or obtain image blocks 203 (current image blocks 203 of a current picture 201) and reconstructed slice data, e.g. reference samples of the same (current) picture from the buffer 216 and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and to process such data for prediction, i.e. to provide a prediction block 265, which may be an inter-predicted block 245 or an intra-predicted block 255.

The mode selection unit 262 may be used to select a prediction mode (e.g., intra or inter prediction mode) and/or a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.

Embodiments of mode selection unit 262 may be used to select the prediction mode (e.g., from those supported by prediction processing unit 260) that provides the best match or minimum residual (minimum residual meaning better compression in transmission or storage), or that provides the minimum signaling overhead (minimum signaling overhead meaning better compression in transmission or storage), or both. The mode selection unit 262 may be adapted to determine a prediction mode based on a rate-distortion optimization (rate distortion optimization, RDO), i.e. to select the prediction mode that provides the least rate-distortion optimization, or to select a prediction mode for which the associated rate-distortion at least meets a prediction mode selection criterion.

The prediction processing performed by an instance of encoder 20 (e.g., by prediction processing unit 260) and the mode selection performed (e.g., by mode selection unit 262) will be explained in detail below.

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

The set of intra prediction modes may include 35 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.265, or 67 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.266 under development.

In a possible implementation, the set of inter prediction modes depends on the available reference pictures (i.e. at least part of the decoded pictures stored in the DBP 230 as described above, for example) and other inter prediction parameters, e.g. on whether the entire reference picture is used or only a part of the reference picture is used, e.g. a search window area surrounding an area of the current block, to search for the best matching reference block, and/or on whether pixel interpolation like half-pixel and/or quarter-pixel interpolation is applied, e.g. the set of inter prediction modes may comprise advanced motion vector (Advanced Motion Vector Prediction, AMVP) mode and fusion (merge) mode, for example. In particular implementations, the set of inter prediction modes may include an improved control point-based AMVP mode, and an improved control point-based merge mode, according to embodiments of the present invention. In one example, intra-prediction unit 254 may be used to perform any combination of the inter-prediction techniques described below.

In addition to the above prediction modes, embodiments of the present invention may also apply skip modes and/or direct modes.

The prediction processing unit 260 may be further operative to partition the image block 203 into smaller block partitions or sub-blocks, for example, by iteratively using a quad-tree (QT) partition, a binary-tree (BT) partition, or a ternary-tree (TT) partition, or any combination thereof, and to perform prediction for each of the block partitions or sub-blocks, for example, wherein the mode selection includes selecting a tree structure of the partitioned image block 203 and selecting a prediction mode applied to each of the block partitions or sub-blocks.

The inter prediction unit 244 may include a motion estimation (motion estimation, ME) unit (not shown in fig. 2) and a motion compensation (motion compensation, MC) unit (not shown in fig. 2). The motion estimation unit is used to receive or obtain a picture image block 203 (current picture image block 203 of current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, e.g. reconstructed blocks of one or more other/different previously decoded pictures 231, for motion estimation. For example, the video sequence may include a current picture and a previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of, or form, a sequence of pictures that form the video sequence.

For example, encoder 20 may be configured to select a reference block from a plurality of reference blocks of the same or different pictures of a plurality of other pictures, and provide the reference picture and/or an offset (spatial offset) between a position (X, Y coordinates) of the reference block and a position of a current block to a motion estimation unit (not shown in fig. 2) as an inter prediction parameter. This offset is also called Motion Vector (MV).

The motion compensation unit is used to acquire inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to acquire the inter prediction block 245. The motion compensation performed by the motion compensation unit (not shown in fig. 2) may involve fetching or generating a prediction block based on motion/block vectors determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering may generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks available for encoding a picture block. Upon receiving the motion vector for the PU of the current picture block, motion compensation unit 246 may locate the prediction block to which the motion vector points in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with the blocks and video slices for use by decoder 30 in decoding the picture blocks of the video slices.

Specifically, the inter prediction unit 244 may transmit a syntax element including inter prediction parameters (e.g., indication information of an inter prediction mode selected for current block prediction after traversing a plurality of inter prediction modes) to the entropy encoding unit 270. In a possible application scenario, if the inter prediction mode is only one, the inter prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding. It is appreciated that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.

The intra prediction unit 254 is used to obtain, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, for example, reconstructed neighboring blocks, for intra estimation. For example, encoder 20 may be configured to select an intra-prediction mode from a plurality of (predetermined) intra-prediction modes.

Embodiments of encoder 20 may be used to select an intra-prediction mode based on optimization criteria, such as based on a minimum residual (e.g., the intra-prediction mode that provides a prediction block 255 most similar to current picture block 203) or minimum rate distortion.

The intra prediction unit 254 is further adapted to determine an intra prediction block 255 based on intra prediction parameters like the selected intra prediction mode. In any case, after the intra-prediction mode for the block is selected, the intra-prediction unit 254 is also configured to provide the intra-prediction parameters, i.e., information indicating the selected intra-prediction mode for the block, to the entropy encoding unit 270. In one example, intra-prediction unit 254 may be used to perform any combination of intra-prediction techniques.

Specifically, the intra-prediction unit 254 may transmit a syntax element including an intra-prediction parameter (such as indication information of an intra-prediction mode selected for the current block prediction after traversing a plurality of intra-prediction modes) to the entropy encoding unit 270. In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding.

The entropy encoding unit 270 is configured to apply an entropy encoding algorithm or scheme (e.g., a variable length coding (variable length coding, VLC) scheme, a Context Adaptive VLC (CAVLC) scheme, an arithmetic coding scheme, a context adaptive binary arithmetic coding (context adaptive binary arithmetic coding, CABAC), a syntax-based context-based binary arithmetic coding (SBAC), a probability interval partitioning entropy (probability interval partitioning entropy, PIPE) coding, or other entropy encoding methods or techniques) to one or all of the quantized residual coefficients 209, inter-prediction parameters, intra-prediction parameters, and/or loop filter parameters (or not) to obtain encoded picture data 21 that may be output by the output 272 in the form of, for example, an encoded bitstream 21. The encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30. Entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.

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

It should be appreciated that other structural variations of video encoder 20 may be used to encode the video stream. For example, for some image blocks or image frames, video encoder 20 may directly quantize the residual signal without processing by transform processing unit 206, and accordingly without processing by inverse transform processing unit 212; alternatively, for some image blocks or image frames, video encoder 20 does not generate residual data and accordingly does not need to be processed by transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; alternatively, video encoder 20 may store the reconstructed image block directly as a reference block without processing via filter 220; alternatively, quantization unit 208 and inverse quantization unit 210 in video encoder 20 may be combined together. The loop filter 220 is optional, and in the case of lossless compression encoding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be appreciated that inter-prediction unit 244 and intra-prediction unit 254 may be selectively enabled depending on the different application scenarios.

Referring to fig. 3, fig. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the invention. Video decoder 30 is operative to receive encoded picture data (e.g., encoded bitstream) 21, e.g., encoded by encoder 20, to obtain decoded picture 231. During the decoding process, video decoder 30 receives video data, such as an encoded video bitstream representing picture blocks of an encoded video slice and associated syntax elements, from video encoder 20.

In the example of fig. 3, decoder 30 includes entropy decoding unit 304, inverse quantization unit 310, inverse transform processing unit 312, reconstruction unit 314 (e.g., summer 314), buffer 316, loop filter 320, decoded picture buffer 330, and prediction processing unit 360. The prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding pass that is substantially reciprocal to the encoding pass described with reference to video encoder 20 of fig. 2.

Entropy decoding unit 304 is used to perform entropy decoding on encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in fig. 3), e.g., any or all of inter-prediction, intra-prediction parameters, loop filter parameters, and/or other syntax elements (decoded). Entropy decoding unit 304 is further configured to forward inter-prediction parameters, intra-prediction parameters, and/or other syntax elements to prediction processing unit 360. Video decoder 30 may receive syntax elements at the video stripe level and/or the video block level.

Inverse quantization unit 310 may be functionally identical to inverse quantization unit 110, inverse transform processing unit 312 may be functionally identical to inverse transform processing unit 212, reconstruction unit 314 may be functionally identical to reconstruction unit 214, buffer 316 may be functionally identical to buffer 216, loop filter 320 may be functionally identical to loop filter 220, and decoded picture buffer 330 may be functionally identical to decoded picture buffer 230.

The prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, where the inter prediction unit 344 may be similar in function to the inter prediction unit 244 and the intra prediction unit 354 may be similar in function to the intra prediction unit 254. The prediction processing unit 360 is typically used to perform block prediction and/or to obtain a prediction block 365 from the encoded data 21, as well as to receive or obtain prediction related parameters and/or information about the selected prediction mode (explicitly or implicitly) from, for example, the entropy decoding unit 304.

When a video slice is encoded as an intra-coded (I) slice, the intra-prediction unit 354 of the prediction processing unit 360 is used to generate a prediction block 365 for a picture block of the current video slice based on the signaled intra-prediction mode and data from a previously decoded block of the current frame or picture. When a video frame is encoded as an inter-coded (i.e., B or P) slice, an inter-prediction unit 344 (e.g., a motion compensation unit) of prediction processing unit 360 is used to generate a prediction block 365 for a video block of the current video slice based on the motion vector and other syntax elements received from entropy decoding unit 304. For inter prediction, a prediction block may be generated from one reference picture within one reference picture list. Video decoder 30 may construct a reference frame list based on the reference pictures stored in DPB330 using default construction techniques: list 0 and list 1.

The prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by parsing the motion vector and other syntax elements, and generate a prediction block for the current video block being decoded using the prediction information. In an example of this disclosure, prediction processing unit 360 uses some syntax elements received to determine a prediction mode (e.g., intra or inter prediction) for encoding video blocks of a video slice, an inter prediction slice type (e.g., B slice, P slice, or GPB slice), construction information for one or more of a reference picture list of the slice, motion vectors for each inter-encoded video block of the slice, inter prediction state for each inter-encoded video block of the slice, and other information to decode video blocks of a current video slice. In another example of the present disclosure, the syntax elements received by video decoder 30 from the bitstream include syntax elements received in one or more of an adaptive parameter set (adaptive parameter set, APS), a sequence parameter set (sequence parameter set, SPS), a picture parameter set (picture parameter set, PPS), or a slice header.

Inverse quantization unit 310 may be used to inverse quantize (i.e., inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by entropy decoding unit 304. The inverse quantization process may include using quantization parameters calculated by video encoder 20 for each video block in a video stripe to determine the degree of quantization that should be applied and likewise the degree of inverse quantization that should be applied.

The inverse transform processing unit 312 is configured to apply an inverse transform (e.g., an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients in order to generate a residual block in the pixel domain.

A reconstruction unit 314 (e.g., a summer 314) is used to add the inverse transform block 313 (i.e., the reconstructed residual block 313) to the prediction block 365 to obtain a reconstructed block 315 in the sample domain, e.g., by adding sample values of the reconstructed residual block 313 to sample values of the prediction block 365.

Loop filter unit 320 is used (during or after the encoding cycle) to filter reconstructed block 315 to obtain filtered block 321, to smooth pixel transitions or improve video quality. In one example, loop filter unit 320 may be used to perform any combination of the filtering techniques described below. Loop filter unit 320 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, an adaptive loop filter (adaptive loop filter, ALF), or a sharpening or smoothing filter, or a collaborative filter. Although loop filter unit 320 is shown in fig. 3 as an in-loop filter, in other configurations loop filter unit 320 may be implemented as a post-loop filter.

The decoded video blocks 321 in a given frame or picture are then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.

Decoder 30 is for outputting decoded picture 31, e.g., via output 332, for presentation to a user or for viewing by a user.

Other variations of video decoder 30 may be used to decode the compressed bitstream. For example, decoder 30 may generate the output video stream without loop filter unit 320. For example, the non-transform based decoder 30 may directly inverse quantize the residual signal without an inverse transform processing unit 312 for certain blocks or frames. In another implementation, video decoder 30 may have inverse quantization unit 310 and inverse transform processing unit 312 combined into a single unit.

In particular, in an embodiment of the present invention, the decoder 30 may be used to implement the video decoding method described in the later embodiments.

Specifically, the acquiring unit in the embodiment of the present invention may be the entropy decoding unit 304 or the communication interface 28 or the antenna 42. Specifically, the determining unit in the embodiment of the present invention may be the decoder 30 or the inverse quantization unit 310 or the inverse transform processing unit 312, or a specific fast dividing unit located before the inverse quantization unit or the inverse transform processing unit, or the entropy decoding unit 304. In particular, the reconstruction unit may be the reconstruction unit 314.

It should be appreciated that other structural variations of video decoder 30 may be used to decode the encoded video bitstream. For example, video decoder 30 may generate an output video stream without processing by filter 320; alternatively, for some image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode quantized coefficients, and accordingly does not need to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312. Loop filter 320 is optional; and for the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional. It should be appreciated that the inter prediction unit and the intra prediction unit may be selectively enabled according to different application scenarios.

It should be understood that, in the encoder 20 and the decoder 30 of the present application, the processing result for a certain link may be further processed and then output to a next link, for example, after the links such as interpolation filtering, motion vector derivation or loop filtering, the processing result for the corresponding link may be further processed by performing operations such as Clip or shift.

For example, the motion vector of the control point of the current image block derived from the motion vector of the neighboring affine encoded block, or the motion vector of the sub-block of the current image block derived therefrom, may be further processed, which is not limited in the present application. For example, the range of motion vectors is constrained to be within a certain bit width. Assuming that the bit width of the allowed motion vector is bitDepth, the range of motion vectors is-2 (bitDepth-1) to 2 (bitDepth-1) -1, where the "∈" sign represents the power. If the bitDepth is 16, the value range is-32768-32767. If the bitDepth is 18, the value range is-131072 ～ 131071. For another example, the values of the motion vectors (e.g., motion vectors MV of four 4x4 sub-blocks within one 8x8 image block) are constrained such that the maximum difference between the integer parts of the four 4x4 sub-blocks MV does not exceed N pixels, e.g., does not exceed one pixel.

The constraint can be made within a certain positioning width by the following two ways:

mode 1, the high order overflow of the motion vector is removed:

ux＝(vx+2 ^bitDepth )％2 ^bitDepth

vx＝(ux＞＝2 ^bitDepth-1 )？(ux-2 ^bitDepth )：ux

uy＝(vy+2 ^bitDepth )％2 ^bitDepth

vy＝(uy＞＝2 ^bitDepth-1 )？(uy-2 ^bitDepth )：uy

wherein vx is a horizontal component of a motion vector of an image block or a sub-block of the image block, vy is a vertical component of a motion vector of an image block or a sub-block of the image block, ux and uy are intermediate values; bitDepth represents the bit width.

For example vx has a value of-32769 and 32767 by the above formula. Because in the computer the values are stored in the form of two's complement, -32769's complement is 1, 0111, 1111, 1111 (17 bits), the computer discards the high order bits for the overflow, the vx values are 0111, 1111, 1111, 1111, 32767, consistent with the results obtained by the formula processing.

Method 2, clipping the motion vector as shown in the following formula:

vx＝Clip3(-2 ^bitDepth-1 ，2 ^bitDepth-1 -1，vx)

vy＝Clip3(-2 ^bitDepth-1 ，2 ^bitDepth-1 -1，vy)

where vx is the horizontal component of the motion vector of an image block or a sub-block of the image block and vy is the vertical component of the motion vector of an image block or a sub-block of the image block; wherein x, y and z correspond to three input values of MV clamping process Clip3, respectively, the definition of Clip3 is that the value of z is clamped between intervals [ x, y ]:

Referring to fig. 4, fig. 4 is a schematic structural diagram of a video decoding apparatus 400 (e.g., a video encoding apparatus 400 or a video decoding apparatus 400) according to an embodiment of the present invention. The video coding apparatus 400 is adapted to implement the embodiments described herein. In one embodiment, video coding device 400 may be a video decoder (e.g., decoder 30 of fig. 1A) or a video encoder (e.g., encoder 20 of fig. 1A). In another embodiment, video coding apparatus 400 may be one or more of the components described above in decoder 30 of fig. 1A or encoder 20 of fig. 1A.

The video coding apparatus 400 includes: an ingress port 410 and a receiving unit (Rx) 420 for receiving data, a processor, logic unit or Central Processing Unit (CPU) 430 for processing data, a transmitter unit (Tx) 440 and an egress port 450 for transmitting data, and a memory 460 for storing data. The video decoding apparatus 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of optical or electrical signals.

The processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (e.g., multi-core processors), FPGAs, ASICs, and DSPs. Processor 430 is in communication with inlet port 410, receiver unit 420, transmitter unit 440, outlet port 450, and memory 460. The processor 430 includes a coding module 470 (e.g., an encoding module 470 or a decoding module 470). The encoding/decoding module 470 implements embodiments disclosed herein to implement the chroma block prediction methods provided by embodiments of the present invention. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations. Thus, substantial improvements are provided to the functionality of the video coding device 400 by the encoding/decoding module 470 and affect the transition of the video coding device 400 to different states. Alternatively, the encoding/decoding module 470 is implemented in instructions stored in the memory 460 and executed by the processor 430.

Memory 460 includes one or more disks, tape drives, and solid state drives, and may be used as an overflow data storage device for storing programs when selectively executing such programs, as well as storing instructions and data read during program execution. Memory 460 may be volatile and/or nonvolatile and may be Read Only Memory (ROM), random Access Memory (RAM), random access memory (TCAM) and/or Static Random Access Memory (SRAM).

Referring to fig. 5, fig. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of the source device 12 and the destination device 14 in fig. 1A, according to an example embodiment. The apparatus 500 may implement the techniques of the present application. In other words, fig. 5 is a schematic block diagram of one implementation of an encoding device or decoding device (simply referred to as decoding device 500) of an embodiment of the present application. The decoding device 500 may include, among other things, a processor 510, a memory 530, and a bus system 550. The processor is connected with the memory through the bus system, the memory is used for storing instructions, and the processor is used for executing the instructions stored by the memory. The memory of the decoding device stores program code and the processor may invoke the program code stored in the memory to perform the various video encoding or decoding methods described herein, particularly the various new video decoding methods. To avoid repetition, a detailed description is not provided herein.

In an embodiment of the present application, the processor 510 may be a central processing unit (Central Processing Unit, abbreviated as "CPU"), and the processor 510 may also be other general purpose processors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), off-the-shelf programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 530 may include a Read Only Memory (ROM) device or a Random Access Memory (RAM) device. Any other suitable type of storage device may also be used as memory 530. Memory 530 may include code and data 531 accessed by processor 510 using bus 550. Memory 530 may further include an operating system 533 and an application 535, which application 535 includes at least one program that allows processor 510 to perform the video encoding or decoding methods described herein. For example, applications 535 may include applications 1 through N, which further include video encoding or decoding applications (simply video coding applications) that perform the video encoding or decoding methods described in this disclosure.

The bus system 550 may include a power bus, a control bus, a status signal bus, and the like in addition to a data bus. For clarity of illustration, the various buses are labeled in the figure as bus system 550.

Optionally, the decoding device 500 may also include one or more output devices, such as a display 570. In one example, the display 570 may be a touch sensitive display that incorporates a display with a touch sensitive unit operable to sense touch input. A display 570 may be connected to processor 510 via bus 550.

In some implementations, differences in CU, PU, and TU concepts may be avoided and more flexibility in CU shape is supported. The size of a CU corresponds to the size of the encoding node, and a CU may be square or non-square (e.g., rectangular) in shape.

In some embodiments, the size of the largest TU may be set, and when the size of the CU is greater than the size of the largest TU, the CU may be further divided such that the size of the obtained TU is less than or equal to the size of the largest TU. Where the size of the largest TU, although not, refers to the height and/or width of the largest TU.

In some embodiments, transformation is allowed according to TUs. In some scenarios, the leaf nodes of the residual quadtree (residual quad tree, RQT) may be referred to as TUs, a leaf CU may include a quadtree indicating how the leaf CU is split into TUs (e.g., a partition flag may indicate whether the leaf CU is split into four transform units), and the root node of the TU quadtree generally corresponds to the leaf CU, while the root node of the CU quadtree generally corresponds to a treeblock (or LCU). Pixel differences associated with TUs may be transformed to generate transform coefficients, which may be quantized.

It should be noted that a Transform Unit (TU) is a basic unit for performing transform and quantization, and is generated by dividing on the basis of a CU. The CU to TU partitioning may use quadtree partitioning (QT). A Three Tree (TT) division may be used, or a Binary Tree (BT) division may be used.

Quadtree partitioning refers to partitioning a corresponding image region into four equally sized regions (each of which is half as long and as wide as the partitioned region, and one node for each region.

Binary tree partitioning refers to partitioning a node into corresponding nodes in a binary tree fashion. There are two specific binary tree partitioning modes:

1) Dividing the area corresponding to the node into an upper area and a lower area with the same size (namely, the width is unchanged, the height is changed into half of the area before division), and each area corresponds to one node;

2) The vertical bisection divides the area corresponding to the node into a left area and a right area with the same size (namely, the height is unchanged, and the width is changed into half of the area before division).

The coding division mode of the three-way tree, namely one node can be divided into 3 nodes in the three-way tree mode. The specific three-tree dividing mode comprises two modes of horizontal trisection and vertical trisection.

The cbf flag (Coding Block Flag) at the CU level indicates whether there is a residual after the current coding block (or referred to as a coding unit, CU) is coded, cbf=0 indicates that there is no residual after the current coding block is coded, and cbf=1 indicates that there is a residual after the current coding block is coded. Alternatively, a cbf flag (Coding Block Flag) at the CU level indicates whether a current coding block (or referred to as a coding unit, CU) needs to be further divided into TUs or whether the current coding block has a transform tree (transform_tree) related syntax structure.

The rqt _root_cbf flag (Residual Quadtree Root Cbf) is a CU-level cbf flag introduced by HEVC. In the coding unit syntax defined by HEVC, rqt _root_cbf is used to indicate whether there is a residual after the current CU is encoded. If rqt _root_cbf is 1, the coding syntax structure of the transform tree is used in the cu syntax, thus containing the residual; if rqt _root_cbf is 0, the cu syntax does not use the coding syntax structure of the transform tree, so that there is no residual. From the above, after rqt _root_cbf is introduced, the CU can choose whether to write the residual into the bitstream, thereby saving the code rate. The partial syntax at CU level at this time is as in table 1:

the flag bit is used to indicate whether there is a residual after encoding the current CU or to indicate whether the current encoded block has a transform tree (transform_tree) related syntax structure, such as the rqt _root_cbf flag bit in HEVC or the cu_cbf flag bit in VVC draft2, collectively referred to herein as the cu_cbf flag bit. cu_cbf=1 indicates that there is a residual after the current block is encoded, and the coding syntax encoding structure of the transform tree is used, and cu_cbf=0 indicates that there is no residual after the current block is encoded, and the coding syntax encoding structure of the transform tree is not used.

The transform tree (HEVC) syntax is shown in table 2.

Wherein the syntax element split_transform_flag [ x0] [ y0] [ trafoDepth ] represents whether the current block is to be divided into TUs of small blocks for the process of transform coding. The array index x0, y0 specifies the coordinate position (x 0, y 0) of the upper left luma sample of the current block relative to the upper left luma sample of the image. trafoDepth represents the division depth of the current transform tree node in the transform tree, and trafoDepth of the transform tree node of the same size as the current coding block is 0.

In addition, there are TU levels cbf_luma (cbf of luminance component), cbf_cr (cbf of red chrominance component) and cbf_cb (cbf of blue chrominance component). The cbf_luma flag is used to indicate whether the current TU or the luma component of the transform tree node contains a non-zero transform coefficient (transform coefficient), the syntax element cbf_luma [ x0] [ y0] [ trafoDepth ] = 1 indicates that the luma transform block contains a non-zero transform coefficient, and cbf_luma [ x0] [ y0] [ trafoDepth ] = 0 indicates that the luma transform block does not contain a non-zero transform coefficient.

cbf_cb is used to indicate whether non-zero transform coefficients are included in a Chroma blue (Cb) transform block of a current TU or transform tree node. The syntax element cbf_cb [ x0] [ y0] [ trafoDepth ] =1 indicates that the Cb transform block contains non-zero transform coefficients, and cbf_cb [ x0] [ y0] [ trafoDepth ] =0 indicates that the Cb transform block does not contain non-zero transform coefficients.

cbf_cr is used to indicate whether non-zero transform coefficients are included in a Chroma red (Cr) transform block of a current TU or transform tree node. The syntax element cbf_cr [ x0] [ y0] [ trafoDepth ] =1 indicates that the Cr transform block contains non-zero transform coefficients, and cbf_cr [ x0] [ y0] [ trafoDepth ] =0 indicates that the Cr transform block does not contain non-zero transform coefficients.

TABLE 2

Specifically, as a video decoding method provided by the embodiment of the present invention, a cbf determining method (video decoding method) of each TU in a transform tree of a current coding block may be as follows:

step 1: the cu_cbf identification of the current CU is determined.

The method for determining the cu_cbf may be analytically derived or derived from the code stream.

If the current coding block cu_cbf=1, step 2 is performed.

Step 2: a TU partition of the current CU is determined or whether the current CU needs to be partitioned into at least two TUs is determined.

A CU may contain one TU of the same size as a CU, or a CU may be divided into multiple TUs.

In some implementations, the partitioning of the current CU into multiple TUs may be a Quadtree (QT) partition, which may be determined by a syntax element split_transform_flag identification.

In some implementations, if both the width W and the height H of the current CU are greater than the maximum TU size (maximum transform size) TS, the current CU is divided into 4 TUs each of which is the maximum TU size, i.e., 4 TUs; if the width of the current CU is larger than the maximum TU size but is smaller than or equal to the maximum TU size, dividing the current CU into 2 TUs; if the height of the previous CU is greater than the maximum TU size but the width is less than or equal to the maximum TU size, the current CU is divided into 2 TUs; since it is judged whether or not the partition is made by the width and height of the CU, it is not identified by the syntax element.

If the current CU is divided into at least 2 TUs, steps 3 to 6 are performed. The execution sequence of steps 3 to 6 may not be limited, for example, step four may precede step three.

Step 3: the cbf_cb and cbf_cr of the transform tree node (transform tree node) are parsed from the code stream. The transform tree node may be trafodepth=0.

The transform tree node of trafodepth=0 may be a transform tree node indicating that the current CU does not divide into TUs (or resulting image blocks), or the transform tree node of trafodepth=0 may be the current CU. The syntax structure of the transform tree node is shown as the transform_tree () syntax structure in table 2.

Step 4: if a CU needs to be partitioned into N (N > 1) TUs, the CU is further partitioned into N TUs, where N may be 2,3, or 4. Wherein the N TUs may be trafodepth=1.

Step 5: and analyzing cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ] of the first N-1 TUs in the N TUs from the code stream, wherein i=1. The cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ] of the first N-1 TUs appear in the bitstream, and entropy decoding requires parsing the corresponding bits (bins) to determine the values of cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ].

Step 6: and analyzing the cbf_luma [ i ], the cbf_cb [ i ] and the cbf_cr [ i ] of the N TU in the N TUs from the code stream. Cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ] of the nth TU appear in the bitstream.

Through the above steps, the cbf_luma and cbf_cb, cbf_cr identification of each TU in the transform tree may be determined.

When the cu_cbf of the current CU is parsed to be 1, the cbf_luma and the cbf_cb of each TU of the transform tree, cbf_cr identifiers, respectively, need to be parsed from the bitstream, and in some cases, the cbf identifier of the last TU may be derived from the cbf identifier that has been parsed before, without being obtained from the bitstream, thereby improving encoding and decoding efficiency. The specific scheme can be as follows: when it is determined that the cu_cbf of the current CU is 1, the cbf identification of the chroma component or luma component of the last TU may be determined from the cbf of the already parsed TU without parsing from the bitstream, which includes at least one of the following methods:

1) If cbf_cb of the transform tree node is 0, cbf_cr is 0, and cbf_luma [ i ] (i=1,..n-1) of the first N-1 TUs are all 0, then cbf_luma [ i ] (i=n) of the nth TU is determined to default to 1.

2) If cbf_cb of the transform tree node is 1 and cbf_cb [ i ] of the first N-1 TUs (i=1,..n-1) are all 0, cbf_cb [ i ] of the nth TU defaults to 1.

3) If cbf_cr of the transform tree node is 1 and cbf_cr [ i ] of the first N-1 TUs (i=1,..n-1) are all 0, cbf_cr [ i ] of the nth TU defaults to 1.

As another video decoding method provided by the embodiment of the present invention, the corresponding decoding method may include the following steps (the following steps are similar to the previous steps 1 to 6 in some content, and similar content may refer to the previous steps 1 to 6, and are not repeated here):

step 1: the cu_cbf identification of the current CU is determined.

If the current coding block cu_cbf=1, step 2 is performed.

Specifically, the partitioning manner of the current CU into multiple TUs may be obtained by parsing a syntax element, or may be determined according to the width, height, and size of the maximum transform block of the CU. The division may be one of Binary Tree (BT), trigeminal Tree (TT) and Quadtree (QT) division.

Binary tree partitioning includes two modes, horizontal bisection and vertical bisection, and CU is partitioned into 2 TUs. The current CU has a size WxH, i.e., W pixels in the horizontal direction and H pixels in the vertical direction. Horizontal bisection divides the current CU level into two Wx (H/2) sized TUs; wherein, TU on the upper side is TU0, TU on the lower side is TU1; vertical bisection vertically divides the current CU into two (W/2) xH-sized TUs; where the TU on the left is TU0 and the TU on the right is TU1, their trafoDepth may be 1, as shown in FIG. 6.

The trigeminal tree partition includes two modes, horizontal trisection and vertical trisection, dividing a CU into 3 TUs. Horizontal trisection divides the current CU level into two Wx (H/4) sized TUs and one Wx (H/2) sized TU; wherein, the TU at the upper side is TU0, the TU at the middle is TU1, and the TU at the lower side is TU2. Vertical trisection vertically divides the current CU into two (W/4) xH-sized TUs and one (W/2) xH-sized TU; where the TU on the left is TU0, the TU on the middle is TU1, the TU on the right is TU2, their trafoDepth may be 1, as shown in FIG. 7.

Quadtree partitioning, such as the quadtree partitioning in HEVC, partitions a CU into 4 TUs, each TU being (W/2) x (H/2), or (W/4) x (H), or (W) x (H/4).

Step 3: and analyzing the code stream to obtain cbf_cb and cbf_cr of the transformation tree node. The transform tree node may be trafodepth=0. The cbf_luma of the transform tree node may also be parsed from the codestream.

The transform tree node of trafodepth=0 may be a transform tree node indicating that the current CU is not partitioned to obtain a TU, or indicating that the current CU is a TU, or indicating that trafodepth=0 is the current CU.

Step 4: if a CU needs to be partitioned into N (N > 1) TUs, the CU is further partitioned into N TUs, where N may be 2, 3, or 4. The partitioning may be one of BT, TT and QT. Wherein the N TUs may be trafodepth=1.

Step 5: and analyzing cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ] of the first N-1 TUs in the N TUs from the code stream, wherein i=1.

Step 6: determining cbf_luma [ i ], cbf_cb [ i ] and cbf_cr [ i ] of an nth TU of the N TUs, including at least one of the following processes:

1) If cbf_cb and cbf_cr of the transform tree nodes are both 0 and cbf_luma [ i ] of the first N-1 TUs (i=1,..n-1) are both 0, cbf_luma [ i ] (i=n) of the nth TU is set to 1 and cbf_luma [ i ] (i=n) is not present in the bitstream. Otherwise, the bitstream is parsed to determine cbf_luma [ i ] (i=n), which occurs in the bitstream.

2) If cbf_cb of the transform tree node is 1 and cbf_cb [ i ] of the first N-1 TUs (i=1,..n-1) are all 0, cbf_cb [ i ] of the nth TU is set to 1 and cbf_cb [ i ] (i=n) is not present in the bitstream. Otherwise, the stream is parsed to determine cbf_cb [ i ] (i=n), which occurs in the stream.

3) If cbf_cr of the transform tree node is 1 and cbf_cr [ i ] of the first N-1 TUs (i=1,..n-1) are all 0, cbf_cr [ i ] of the nth TU is set to 1 and cbf_cr [ i ] (i=n) is not present in the bitstream. Otherwise, the parsed code stream determines cbf_cr [ i ] (i=n), which appears in the code stream.

The method for checking that cbf_luma [ i ] of the previous N-1 TUs is 0 may be adopted in the following manner, for a transformation tree node of the current CU, setting a variable IsNoneZeroCbfLuma Signaled to 0, and in the process of analyzing the cbf_luma [ i ] of the N TUs of the current CU, if the cbf_luma [ i ] of one TU is 1, setting the variable IsNoneZeroCbfLuma Signaled to 1. In parsing cbf_luma [ i ] of the nth TU, if isnonezerocbfluma signaled is 0, that is, cbf_luma [ i ] of the first N-1 TUs is 0, cbf_luma [ i ] (i=n) of the nth TU is set to 1.

Similarly, the method of checking that cbf_cb [ i ] of the previous N-1 TUs are all 0 may be adopted in such a way that, for the transform tree node of the current CU, the variable isnene zerocbfcbbsignaled is set to 0, and in parsing cbf_cb [ i ] of the N TUs of the current CU, if cbf_cb [ i ] of one TU is 1, the variable isnene zerocbfcbbsignaled is set to 1. In parsing cbf_cb [ i ] of the nth TU, if isnonezerocbfcbcb signaled is 0, cbf_cb [ i ] representing the first N-1 TUs are all 0, cbf_cb [ i ] of the nth TU is set to 1 (i=n).

Similarly, the method of checking that cbf_cr [ i ] of the previous N-1 TUs is 0 may be adopted in such a way that, for the transform tree node of the current CU, the variable isnene zerocbfcrcsignaling is set to 0, and in the process of parsing cbf_cr [ i ] of the N TUs of the current CU, if cbf_cr [ i ] of one TU is 1, the variable isnene zerocbfcsignaling is set to 1. In parsing cbf_cb [ i ] of the nth TU, if isnonezerocbfccrsignald is 0, that means cbf_cr [ i ] of the first N-1 TUs are all 0, cbf_cr [ i ] (i=n) of the nth TU is set to 1.

Through the above steps, the cbf_luma and cbf_cb, cbf_cr identifications of the respective TUs in the transform tree of the current CU may be determined.

The present invention is not limited to the parsing method of cbf when the current coding block corresponds to one TU, and for example, a method in the prior art, such as HEVC, may be used.

Fig. 8 is a schematic flow chart of a video decoding method according to an embodiment of the present application. The method may be performed by a device or component associated with the decoding above. The method shown in fig. 8 includes the steps of:

s801, obtaining coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in N transform tree sub-nodes of a current transform tree node, wherein N is an integer greater than 1.

In one possible implementation, the obtaining (Coding Block Flag) the coded block identification of N-1 transform tree sub-nodes of the N transform tree sub-nodes of the current transform tree node is performed in case it is determined that the current transform tree node is divided into N transform tree sub-nodes.

In one possible implementation, the N is 2,3 or 4.

In one possible implementation, the N-1 transform tree sub-nodes are the first N-1 transform tree sub-nodes of the N transform tree sub-nodes.

In one possible implementation, the N transform tree sub-nodes are N Transform Units (TUs), and/or the current transform tree node is a Coding Unit (CU) or a sub-block of a coding unit.

S802, determining the value of the coding block identifier (Coding Block Flag) of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to the value of the coding block identifier of the N-1 transformation tree sub-nodes.

In a possible implementation manner, the determining, according to the value of the code block identifier of the N-1 transform tree sub-nodes, the value of the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes may include: determining whether to analyze the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes; and determining the value of the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node under the condition that the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not analyzed.

In a possible implementation manner, the determining, according to the value of the code block identifier of the N-1 transform tree sub-nodes, the value of the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes may include: determining whether values of coding block identifications of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients; in the case that it is determined that the values of the code block identifications of the N-1 transform tree sub-nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, determining that the values of the code block identifications (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicate that one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contain non-zero transform coefficients.

In a possible implementation manner, the determining, according to the value of the code block identifier of the N-1 transform tree sub-nodes, the value of the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes may include: determining whether the values of the coding block identifications of the N-1 transformation tree child nodes are all 0; and under the condition that the values of the coding block identifications of the N-1 transformation tree sub-nodes are all 0, determining that the value of the coding block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes is 1.

In a specific implementation, the method of determining may be that if cbf_luma of a transform tree node is 1 and cbf_luma [ i ] (i=1,..and N-1) of N-1 TUs are all 0, cbf_luma [ i ] (i=n) of an nth TU is set to 1, and cbf_luma [ i ] (i=n) is not present in the bitstream. Otherwise, the bitstream is parsed to determine cbf_luma [ i ] (i=n), which occurs in the bitstream.

In a specific implementation, the method of determination may be if cbf_cb of the transform tree node is 1, and cbf_cb [ i ] of the first N-1 TUs (i=1, N-1) are all 0, then cbf_cb [ i ] (i=n) of the nth TU is set to 1 and cbf_cb [ i ] (i=n) is not present in the bitstream. Otherwise, the stream is parsed to determine cbf_cb [ i ] (i=n), which occurs in the stream.

In a specific implementation, the method of determining may be that if cbf_cr of a transform tree node is 1 and cbf_cr [ i ] of the first N-1 TUs (i=1,..and N-1) are all 0, cbf_cr [ i ] of the nth TU is set to 1 and cbf_cr [ i ] (i=n) is not present in the bitstream. Otherwise, the parsed code stream determines cbf_cr [ i ] (i=n), which appears in the code stream.

In a specific implementation, the method of determination may be if the transform tree node is a CU and cu_cbf of the CU is 1, and cbf_luma i of N-1 TUs (i=1, N-1) are all 0, then cbf_luma [ i ] (i=n) of the nth TU is set to 1 and cbf_luma [ i ] (i=n) is not present in the codestream. Otherwise, the bitstream is parsed to determine cbf_luma [ i ] (i=n), which occurs in the bitstream.

In a specific implementation, the method of determining may be that if the transform tree node is a CU and cu_cbf of the CU is 1 and cbf_cb [ i ] of the first N-1 TUs (i=1..once, N-1) are all 0, cbf_cb [ i ] of the nth TU (i=n) is set to 1 and cbf_cb [ i ] (i=n) is not present in the bitstream. Otherwise, the stream is parsed to determine cbf_cb [ i ] (i=n), which occurs in the stream.

In a specific implementation, the method of determination may be if the transform tree node is a CU and cu_cbf of the CU is 1, and cbf_cr [ i ] of the first N-1 TUs (i=1, N-1) are all 0, then cbf_cr [ i ] (i=n) of the nth TU is set to 1, cbf_cr [ i ] (i=n) is not present in the code stream. Otherwise, the parsed code stream determines cbf_cr [ i ] (i=n), which appears in the code stream.

In a specific implementation, the method of determination may be that if cbf_luma [ i ] (i=1,.,. N-1) of N-1 TUs are all 0, cbf_luma [ i ] (i=n) of the nth TU is set to 1, and cbf_luma [ i ] (i=n) is not present in the bitstream. Otherwise, the bitstream is parsed to determine cbf_luma [ i ] (i=n), which occurs in the bitstream.

In a specific implementation, the method of determination may be that if cbf_cb [ i ] (i=1,..n-1) of the first N-1 TUs are all 0, cbf_cb [ i ] (i=n) of the nth TU is set to 1, and cbf_cb [ i ] (i=n) is not present in the bitstream. Otherwise, the stream is parsed to determine cbf_cb [ i ] (i=n), which occurs in the stream.

In a specific implementation, the method of determination may be that if cbf_cr [ i ] (i=1,..n-1) of the first N-1 TUs are all 0, cbf_cr [ i ] (i=n) of the nth TU is set to 1, and cbf_cr [ i ] (i=n) is not present in the bitstream. Otherwise, the parsed code stream determines cbf_cr [ i ] (i=n), which appears in the code stream.

S803, reconstructing the current transformation tree node according to the values of the coding block identifiers of the N transformation tree child nodes.

Wherein reconstructing the current transform tree node may also be expressed as obtaining the decoded image block indicated by the current transform tree node.

In one possible implementation, the method may further include: a coded block identification of the current transform tree node is obtained (coding block flag). Correspondingly, the determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes comprises: and determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes and the value of the coding block identifier of the current transform tree node.

Fig. 9 is a schematic flow chart of a video encoding method according to an embodiment of the present application. The method may be performed by the apparatus or component related to the encoding above. The method shown in fig. 9 includes the steps of:

s901, determining the values of coding block identifiers (Coding Block Flag) of N-1 transform tree sub-nodes in N transform tree sub-nodes of the current transform tree node, wherein N is an integer greater than 1.

In one implementation, where the current transform tree node is determined to be partitioned into N transform tree sub-nodes, the determining of the value of the encoded block identification (Coding Block Flag) of N-1 of the N transform tree sub-nodes of the current transform tree node is performed.

In one implementation, the N is 2,3, or 4.

In one implementation, the N-1 transform tree child nodes are the first N-1 of the N transform tree child nodes.

In one implementation, the N transform tree child nodes are N Transform Units (TUs).

In one implementation, the current transform tree node is a Coding Unit (CU).

S902, determining whether the coding block identification (Coding Block Flag) of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is coded into the code stream of the current transformation tree node according to the coding block identification value of the N-1 transformation tree sub-nodes.

In one implementation, the determining whether to program the code stream to which the current transform tree node belongs with the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes according to the value of the code block identifiers of the N-1 transform tree sub-nodes may include: determining whether the value of the coding block identification of the N-1 transform tree sub-nodes indicates that none of the coding blocks of the N-1 transform tree nodes contain non-zero transform coefficients, meaning that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is not encoded into the code stream to which the current transform tree node belongs, and the value of the coding block identification of the N-1 transform tree sub-nodes indicates that the coding block of at least one of the N-1 transform tree nodes contains non-zero transform coefficients, meaning that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes is encoded into the code stream to which the current transform tree node belongs.

In one implementation, the determining whether to program the code stream to which the current transform tree node belongs with the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes according to the value of the code block identifiers of the N-1 transform tree sub-nodes may include: determining whether the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0, wherein the values of the coding block identifications of the N-1 transform tree sub-nodes are all 0 means that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not coded into the code stream to which the current transform tree node belongs, and at least one of the values of the coding block identifications of the N-1 transform tree sub-nodes is 1 means that the coding block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is coded into the code stream to which the current transform tree node belongs.

S903, under the condition that the code block identification (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not coded into the code stream of the current transform tree node, the code block identification (Coding Block Flag) of the N-1 transform tree sub-node is coded into the code stream of the current transform tree node, and the code stream which does not contain the code block identification or the code data of the code block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is obtained.

In one implementation, the method may further include: determining a value of a coding block identification (coding block flag) of the current transform tree node; correspondingly, the determining whether to encode the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into the code stream to which the current transform tree node belongs according to the value of the code block identifier of the N-1 transform tree sub-nodes may include: determining whether to encode the code stream of the current transformation tree node with the code block identification (Coding Block Flag) of one transformation tree sub-node except the N-1 transformation tree sub-nodes in the N transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes and the code block identification (coding block flag) of the current transformation tree node. Based on the same inventive concept as the above method, the embodiment of the present application further provides a video decoding apparatus, as shown in fig. 10, which is a schematic block diagram of a video decoding apparatus 1000 provided in the embodiment of the present application. The apparatus 1000 may be specifically configured to perform any one of the video decoding methods provided in the embodiments of the present application. The apparatus 1000 comprises an acquisition unit 1002, a determination unit 1004 and a reconstruction unit 1006, wherein:

An obtaining unit 1002, configured to obtain coding block identifiers (Coding Block Flag) of N-1 transform tree child nodes in N transform tree child nodes of the current transform tree node, where N is an integer greater than 1.

Wherein the acquisition unit 1002 may be the entropy decoding unit 304 or the communication interface 28 or the antenna 42 as above. Specifically, the determining unit 1004 may be the decoder 30 or include one or more of an inverse quantization unit 310, an inverse transform processing unit 312, and a specific block dividing unit located before the inverse quantization unit or the inverse transform processing unit, and an entropy decoding unit 304. In particular, the reconstruction unit may include one or more of an inverse quantization unit 310, an inverse transform processing unit 312, a specific block division unit located before the inverse quantization unit or the inverse transform processing unit, an entropy decoding unit 304, and a reconstruction unit 314.

In one implementation, the obtaining unit 1002 is configured to obtain, if it is determined that the current transform tree node is divided into N transform tree sub-nodes, a coding block identifier of N-1 transform tree sub-nodes among the N transform tree sub-nodes of the current transform tree node (Coding Block Flag).

In one implementation, the N is 2,3, or 4.

In one implementation, the N transform tree sub-nodes are N Transform Units (TUs), and/or the current transform tree node is a Coding Unit (CU) or a sub-block of a coding unit.

A determining unit 1004, configured to determine, according to the values of the coding block identifiers of the N-1 transform tree sub-nodes, the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except for the N-1 transform tree sub-nodes.

In one implementation, the determining unit 1004 is configured to: determining whether to analyze the code block identification of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to the code block identification value of the N-1 transformation tree sub-nodes; and determining the value of the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node under the condition that the coding block identification of one of the N transform tree sub-nodes except the N-1 transform tree sub-node is not analyzed.

In one implementation, the determining unit 1004 is configured to: determining whether values of coding block identifications of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients; in the case that it is determined that the values of the code block identifications of the N-1 transform tree sub-nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, determining that the values of the code block identifications (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicate that one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contain non-zero transform coefficients.

A reconstruction unit 1006, configured to reconstruct the current transform tree node according to the values of the coding block identifiers of the N transform tree child nodes.

In one implementation, the obtaining unit 1002 may be further configured to: acquiring a coding block identification (coding block flag) of the current transform tree node; accordingly, the determining unit 1004 is configured to: and determining the value of the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the coding block identifier of the N-1 transform tree sub-nodes and the value of the coding block identifier of the current transform tree node. Wherein the obtaining unit 1002 may be configured to parse the coding block identification of the current transform tree node from the code stream (coding block flag).

It should be further noted that, the specific implementation process of the acquiring unit, the determining unit and the reconstructing unit may refer to the detailed description of the method embodiments above, and for brevity of the description, this is not repeated here.

The embodiment of the application also provides a video decoding device, as shown in fig. 11, which is a schematic block diagram of a video encoding device 1100 provided by the embodiment of the application. The apparatus 1100 may be specifically configured to perform any one of the video encoding methods provided by the embodiments of the present application. The apparatus 1100 comprises a determining unit 1102 and an encoding unit 1104, wherein:

a determining unit 1102, configured to determine values of coding block identifiers (Coding Block Flag) of N-1 transform tree child nodes among N transform tree child nodes of the current transform tree node, where N is an integer greater than 1.

In one implementation, the N is 2,3, or 4.

In one implementation, the current transform tree node is a Coding Unit (CU).

The determining unit 1102 is further configured to determine whether to encode, according to the value of the coding block identifiers of the N-1 transform tree sub-nodes, the coding block identifier (Coding Block Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs.

In one implementation, the determining unit 1102 may further be configured to: determining a value of a coding block identification (coding block flag) of the current transform tree node; accordingly, the determining unit 1102 is configured to: and determining whether to encode the Coding block identification (Coding B1ock Flag) of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs according to the value of the Coding block identification of the N-1 transform tree sub-nodes and the value of the Coding block identification (Coding block Flag) of the current transform tree node.

In one implementation, the determining unit 1102 may be configured to: in the case that the current transform tree node is determined to be divided into N transform tree sub-nodes, a value of a coded block identification (Coding Block Flag) of N-1 of the N transform tree sub-nodes of the current transform tree node is determined.

And a coding unit 1104, configured to, when it is determined that the code stream to which the current transform tree node belongs is not coded with the code block identifier (Coding Block Flag) of one of the N transform tree sub-nodes other than the N-1 transform tree sub-node, code the code stream to which the current transform tree node belongs with the code block identifier (Coding Block Flag) of the N-1 transform tree sub-node, and obtain a code stream that does not include the code block identifier or the code data of the code block identifier of one of the N transform tree sub-nodes other than the N-1 transform tree sub-node.

Wherein the encoding unit 1104 may be the entropy encoding unit 270 above. Specifically, the determination unit 1004 may be the above transform processing unit 206 or quantization unit 208.

It should be further noted that, the specific implementation process of the determining unit and the encoding unit may refer to the detailed description of the method embodiments above, and for brevity of description, this is not repeated here.

Those of skill in the art will appreciate that the functions described in connection with the various illustrative logical blocks, modules, units, and algorithm steps described in connection with the disclosure herein may be implemented as hardware, software, firmware, or any combination thereof. If implemented in software, the functions described by the various illustrative logical blocks, modules, and steps may be stored on a computer readable medium or transmitted as one or more instructions or code and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media corresponding to tangible media, such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another (e.g., according to a communication protocol). In this manner, a computer-readable medium may generally correspond to (1) a non-transitory tangible computer-readable storage medium, or (2) a communication medium, such as a signal or carrier wave. Data storage media may 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 storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that the computer-readable storage medium and data storage medium do not include connections, carrier waves, signals, or other transitory media, but are actually directed to non-transitory tangible storage media. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, digital Versatile Disc (DVD), and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within 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 logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term "processor" as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Additionally, in some aspects, the functions described by the various illustrative logical blocks, modules, and steps described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combination codec. Moreover, 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 apparatuses, including a wireless handset, an Integrated Circuit (IC), or a set of ICs (e.g., a chipset). The various components, modules, or units are described in this disclosure in order to emphasize functional aspects of the devices for performing the disclosed techniques, but do not necessarily require realization by different hardware units. Indeed, as described above, the various units may be combined in a codec hardware unit in combination with suitable software and/or firmware, or provided by an interoperable hardware unit (including one or more processors as described above).

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

While the application has been described with respect to exemplary embodiments, the scope of the application is not limited thereto, and any changes or substitutions that would be apparent to one skilled in the art are intended to be included within the scope of the application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of video decoding, the method comprising:

under the condition that the current transformation tree node is divided into N transformation tree sub-nodes, acquiring coding block identifiers CBF of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes of the current transformation tree node, wherein N is an integer larger than 1;

determining the value of the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the CBF of the N-1 transform tree sub-nodes;

reconstructing the current transformation tree node according to the CBF values of the N transformation tree child nodes.

2. The method according to claim 1, wherein the method further comprises:

acquiring CBF of the current transformation tree node;

correspondingly, the determining the value of the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-node according to the value of the CBF of the N-1 transform tree sub-node includes:

and determining the value of the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the CBF of the N-1 transform tree sub-nodes and the value of the CBF of the current transform tree node.

3. The method of claim 1, wherein determining the value of the CBF for one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes based on the values of the CBFs for the N-1 transform tree sub-nodes comprises:

determining whether to analyze the CBF of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes according to the CBF values of the N-1 transformation tree sub-nodes;

in the case that it is determined that the CBF of one of the N transform tree sub-nodes other than the N-1 transform tree sub-node is not parsed, a value of the CBF of the one of the N transform tree sub-nodes other than the N-1 transform tree sub-node is determined.

4. A method according to any one of claims 1 to 3, wherein N is 2,3 or 4.

5. A method according to any one of claims 1 to 3, wherein the N-1 transform tree sub-nodes are the first N-1 of the N transform tree sub-nodes.

6. A method according to any of claims 1 to 3, characterized in that the N transform tree sub-nodes are N transform unit TUs and/or the current transform tree node is a coding unit CU or a sub-block of a coding unit.

7. A method according to any one of claims 1 to 3, wherein said determining the value of the CBF of one of said N transform tree sub-nodes other than said N-1 transform tree sub-nodes from the value of the CBF of said N-1 transform tree sub-nodes comprises:

determining whether the values of CBFs of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients;

in the case that it is determined that the values of the CBFs of the N-1 transform tree sub-nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients, determining that the values of the CBFs of one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes indicate that one of the N transform tree sub-nodes other than the N-1 transform tree sub-nodes contain non-zero transform coefficients.

8. A method of video decoding, the method comprising:

acquiring a coding block identifier CBF of a current transformation tree node;

when the current transformation tree node is divided into N transformation tree sub-nodes, CBFs of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes are acquired, wherein N is an integer larger than 1;

determining the value of the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes according to the value of the CBF of the N-1 transform tree sub-nodes and the value of the CBF of the current transform tree node;

and acquiring the image block indicated by the current decoded transformation tree node according to the CBF of the N transformation tree child nodes.

9. The method of claim 8, wherein N is 2,3 or 4.

10. The method according to claim 8 or 9, wherein the N-1 transform tree sub-nodes are the first N-1 of the N transform tree sub-nodes.

11. The method of claim 8 or 9, wherein the N transform tree child nodes are N transform units TUs.

12. The method according to claim 8 or 9, wherein the current transform tree node is a coding unit CU.

13. A method of video encoding, the method comprising:

under the condition that the current transformation tree node is divided into N transformation tree sub-nodes, determining the values of coding identification blocks CBF of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes of the current transformation tree node, wherein N is an integer larger than 1;

determining whether to encode CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream of the current transform tree node according to the CBF value of the N-1 transform tree sub-nodes;

under the condition that the CBF of one transformation tree sub-node except the N-1 transformation tree sub-node in the N transformation tree sub-nodes is not coded into the code stream of the current transformation tree node, the CBF of the N-1 transformation tree sub-node is coded into the code stream of the current transformation tree node, and the code stream of the coded data of the CBF or the CBF of one transformation tree sub-node except the N-1 transformation tree sub-node in the N transformation tree sub-nodes is not contained.

14. The method of claim 13, wherein the method further comprises:

determining a value of CBF for the current transform tree node;

Correspondingly, the determining whether to encode the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-node into the code stream to which the current transform tree node belongs according to the CBF values of the N-1 transform tree sub-nodes includes:

and determining whether the CBF of one of the N transformation tree sub-nodes except the N-1 transformation tree sub-nodes is coded into the code stream of the current transformation tree node according to the CBF values of the N-1 transformation tree sub-nodes and the CBF values of the current transformation tree node.

15. The method of claim 13 or 14, wherein N is 2,3 or 4.

16. The method according to claim 13 or 14, wherein the N-1 transform tree sub-nodes are the first N-1 of the N transform tree sub-nodes.

17. The method of claim 13 or 14, wherein the N transform tree child nodes are N transform units TUs.

18. The method according to claim 13 or 14, wherein the current transform tree node is a coding unit CU.

19. A method of video encoding, the method comprising:

Determining the value of a coding block identifier CBF of a current transformation tree node;

when the current transformation tree node is divided into N transformation tree sub-nodes, determining the CBF values of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes, wherein N is an integer greater than 1;

determining whether to encode the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs according to the CBF value of the N-1 transform tree sub-nodes and the CBF value of the current transform tree node;

20. The method of claim 19, wherein N is 2,3 or 4.

21. The method according to claim 19 or 20, wherein the N-1 transform tree sub-nodes are the first N-1 of the N transform tree sub-nodes.

22. The method of claim 19 or 20 wherein said N transform tree sub-nodes are N transform units TUs.

23. The method according to claim 19 or 20, wherein the current transform tree node is a coding unit CU.

24. A video decoding device, the device comprising:

an obtaining unit, configured to obtain, when it is determined that a current transform tree node is divided into N transform tree sub-nodes, coding block identifiers CBF of N-1 transform tree sub-nodes in the N transform tree sub-nodes of the current transform tree node, where N is an integer greater than 1;

a determining unit, configured to determine, according to the CBF values of the N-1 transform tree sub-nodes, a CBF value of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes;

and the reconstruction unit is used for reconstructing the current transformation tree node according to the CBF values of the N transformation tree child nodes.

25. The apparatus of claim 24, wherein the acquisition unit is further configured to:

acquiring CBF of the current transformation tree node;

correspondingly, the determining unit is used for:

26. The apparatus of claim 24, wherein the determining unit is configured to:

27. The device of any one of claims 24 to 26, wherein N is 2,3 or 4.

28. The apparatus of any one of claims 24 to 26, wherein the N-1 transform tree sub-nodes are a top N-1 of the N transform tree sub-nodes.

29. The apparatus of any one of claims 24 to 26, wherein the N transform tree sub-nodes are N transform unit TUs and/or the current transform tree node is a coding unit CU or a sub-block of a coding unit.

30. The apparatus according to any one of claims 24 to 26, wherein the determining unit is configured to: determining whether the values of CBFs of the N-1 transform tree child nodes indicate that none of the transform blocks of the N-1 transform tree nodes contain non-zero transform coefficients;

31. A video decoding device, the device comprising:

the acquisition unit is used for acquiring the coding block identification CBF of the current transformation tree node;

the obtaining unit is further configured to obtain CBFs of N-1 transform tree sub-nodes in the N transform tree sub-nodes when the current transform tree node is divided into N transform tree sub-nodes, where N is an integer greater than 1;

a determining unit, configured to determine a value of CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-node according to the value of CBF of the N-1 transform tree sub-node and the value of CBF of the current transform tree node;

and the reconstruction unit is used for acquiring the image block indicated by the current decoded transformation tree node according to the CBFs of the N transformation tree child nodes.

32. The device of claim 31, wherein N is 2,3 or 4.

33. The apparatus of claim 31 or 32, wherein the N-1 transform tree sub-nodes are a top N-1 of the N transform tree sub-nodes.

34. The apparatus of claim 31 or 32 wherein said N transform tree sub-nodes are N transform units TUs.

35. The apparatus according to claim 31 or 32, wherein the current transform tree node is a coding unit CU.

36. A video encoding device, the device comprising:

a determining unit, configured to determine values of coding identification blocks CBF of N-1 transform tree sub-nodes among N transform tree sub-nodes of the current transform tree node, where N is an integer greater than 1, in a case where it is determined that the current transform tree node is divided into N transform tree sub-nodes;

the determining unit is further configured to determine, according to the values of CBFs of the N-1 transform tree sub-nodes, whether to encode the CBFs of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs;

And the coding unit is used for coding the CBF of the N-1 transform tree sub-nodes into the code stream of the current transform tree node under the condition that the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes is not coded into the code stream of the current transform tree node, so as to obtain the code stream which does not contain the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes or the coded data of the CBF.

37. The apparatus of claim 36, wherein the determining unit is further configured to:

determining a value of CBF for the current transform tree node;

correspondingly, the determining unit is used for:

38. The device of claim 36 or 37, wherein N is 2,3 or 4.

39. The apparatus of claim 36 or 37, wherein the N-1 transform tree sub-nodes are a top N-1 of the N transform tree sub-nodes.

40. The apparatus of claim 36 or 37 wherein said N transform tree sub-nodes are N transform units TUs.

41. The apparatus according to claim 36 or 37, wherein the current transform tree node is a coding unit CU.

42. A video encoding device, the device comprising:

a determining unit for determining a value of a coding block flag CBF of a current transform tree node; when the current transformation tree node is divided into N transformation tree sub-nodes, determining the CBF values of N-1 transformation tree sub-nodes in the N transformation tree sub-nodes, wherein N is an integer greater than 1; determining whether to encode the CBF of one of the N transform tree sub-nodes except the N-1 transform tree sub-nodes into a code stream to which the current transform tree node belongs according to the CBF value of the N-1 transform tree sub-nodes and the CBF value of the current transform tree node;

43. The device of claim 42, wherein N is 2,3, or 4.

44. The apparatus of claim 42 or 43, wherein the N-1 transform tree sub-nodes are a top N-1 transform tree sub-nodes of the N transform tree sub-nodes.

45. The apparatus of claim 42 or 43 wherein said N transform tree child nodes are N transform units TUs.

46. The apparatus of claim 42 or 43, wherein the current transform tree node is a coding unit CU.

47. A video codec apparatus, the apparatus comprising: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform the method as described in any of claims 1-23.

48. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein a computer program which, when run on a processor, implements the method of any of claims 1-23.