CN112135128A

CN112135128A - Image prediction method, coding tree node division method and device thereof

Info

Publication number: CN112135128A
Application number: CN201910551446.6A
Authority: CN
Inventors: 赵寅; 杨海涛
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2020-12-25

Abstract

The application provides an image prediction method, a coding tree node division method and a device thereof, wherein the image prediction method comprises the following steps: determining the type of a current coding unit, wherein the type of the current coding unit is a brightness and chrominance coding unit, a brightness coding unit or a chrominance coding unit; determining a prediction mode of a current coding unit according to the type of the current coding unit and/or the prediction mode of an adjacent image block, wherein the image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block comprises an adjacent luminance block and/or an adjacent chrominance block; and predicting the image block in the current coding unit according to the prediction mode of the current coding unit. The method in the embodiment of the application can improve the video coding and decoding efficiency.

Description

Image prediction method, coding tree node division method and device thereof

Technical Field

The present application relates to the field of video coding and decoding, and more particularly, to an image prediction method, a coding tree node division method, and an apparatus thereof.

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 "smart phones"), 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), and extensions of such standards. Video devices may transmit, receive, encode, decode, and/or store digital video information more efficiently by implementing such video compression techniques.

Video compression techniques perform spatial (intra-picture) prediction and/or temporal (inter-picture) prediction to reduce or remove 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. An image block in a to-be-intra-coded (I) strip of an image is encoded using spatial prediction with respect to reference samples in neighboring blocks in the same image. An image block in a to-be-inter-coded (P or B) slice 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. A picture may be referred to as a frame and a reference picture may be referred to as a reference frame.

In the entropy encoding and decoding processes, a context model of each bit corresponding to a syntax element needs to be determined according to context information (e.g., encoding information in a reconstructed region around a node corresponding to the syntax element), and this process may be generally referred to as context modeling. However, if the context modeling method is inappropriate, the video coding efficiency is reduced.

Disclosure of Invention

The application provides an image prediction method, a coding tree node division method and a coding tree node division device, which can improve video coding and decoding efficiency.

In a first aspect, a method for image prediction is provided, the method comprising: determining the type of a current coding unit, wherein the type of the current coding unit is a brightness and chrominance coding unit, a brightness coding unit or a chrominance coding unit; determining a prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of an adjacent image block, wherein the image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block comprises an adjacent luminance block and/or an adjacent chrominance block; and predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

According to the method and the device, the prediction mode of the adjacent image block matched with the type of the current coding unit is selected according to the type of the current coding unit, context modeling is carried out, the prediction mode of the current coding unit is determined, and the image block in the current coding unit is predicted according to the prediction mode, so that the video coding and decoding efficiency can be improved.

With reference to the first aspect, in certain implementations of the first aspect, the determining a prediction mode of the current coding unit according to the type of the current coding unit and/or a prediction mode of a neighboring image block includes: determining a context model number corresponding to a syntax element of the current coding unit according to the type of the current coding unit and/or a prediction mode of an adjacent image block; and determining the prediction mode of the current coding unit according to the context model number.

With reference to the first aspect, in certain implementations of the first aspect, the determining, according to the type of the current coding unit and/or a prediction mode of a neighboring image block, a context model number corresponding to a syntax element of the current coding unit includes: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or determining condL according to the prediction mode of the left side adjacent chroma block and determining condA according to the prediction mode of the upper side adjacent chroma block when the current coding unit is the chroma coding unit; determining the context model number according to the condL and the condA; wherein the condL and the condA are binary variables.

In the present application, when the current coding unit is a luma chroma coding unit or a luma coding unit, a context model corresponding to a syntax element of the current coding unit is determined according to a prediction mode of an adjacent luma block, and when the current coding unit is a chroma coding unit, a context model corresponding to a syntax element of the current coding unit is determined according to a prediction mode of an adjacent chroma block, which can ensure that the prediction mode of an adjacent image block selected by context modeling is matched with the type of the current coding unit, thereby reducing the number of coding bits and improving the compression efficiency, and therefore, the efficiency of entropy coding and entropy decoding can be improved.

With reference to the first aspect, in certain implementations of the first aspect, the determining the context model number includes determining the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is the context model number, ctxSetIdx is the number of the context group; when the current coding unit is a luma chroma coding unit or a luma coding unit, the condL indicates whether a prediction mode of the left neighboring luma block is intra block copy prediction, the condA indicates whether a prediction mode of the upper neighboring luma block is intra block copy prediction, the availableL indicates whether the left neighboring luma block is available, and the availableA indicates whether the upper neighboring luma block is available; or, in a case where the current coding unit is a chroma coding unit, the condL indicates whether a prediction mode of the left-side neighboring chroma block is intra block copy prediction, the condA indicates whether a prediction mode of the upper-side neighboring chroma block is intra block copy prediction, the availableL indicates whether the left-side neighboring chroma block is available, and the availableA indicates whether the upper-side neighboring chroma block is available.

With reference to the first aspect, in certain implementations of the first aspect, the determining, according to the type of the current coding unit and/or the prediction mode of the neighboring image block, a context model number corresponding to a syntax element of the current coding unit includes: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; or determining said context model number from said contl and said condA; determining the context model number according to a preset condL and a preset condA under the condition that the current coding unit is a chroma coding unit; wherein the condL and the condA are binary variables.

In this application, when the current coding unit is a chroma coding unit, the condL and the condA are preset values, and at this time, a context model corresponding to a syntax element of the current coding unit is independent of an adjacent image block, so that the complexity of entropy encoding and entropy decoding can be reduced, and the video encoding and decoding efficiency can be improved.

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is the context model number, ctxSetIdx is the number of the context group; when the current coding unit is a luma chroma coding unit or a luma coding unit, the condL indicates whether a prediction mode of the left neighboring luma block is intra block copy prediction, the condA indicates whether a prediction mode of the upper neighboring luma block is intra block copy prediction, the availableL indicates whether the left neighboring luma block is available, and the availableA indicates whether the upper neighboring luma block is available; or in the case that the current coding unit is a chroma coding unit, the condL is a preset value, the condA is a preset value, the availableL indicates whether the left-side neighboring chroma block is available, and the availableA indicates whether the upper-side neighboring chroma block is available.

With reference to the first aspect, in certain implementations of the first aspect, the syntax element is pred _ mode _ ibc _ flag, the syntax element is used to identify whether the current coding unit uses intra block copy prediction, the contl is used to indicate whether a prediction mode of a left neighboring image block is intra block copy prediction, and the condA is used to indicate whether a prediction mode of an upper neighboring image block is intra block copy prediction.

In a second aspect, a coding tree node partitioning method is provided, where the method includes: determining the type of a current coding tree node, wherein the type of the current coding tree node is a brightness and chrominance coding tree node, a brightness coding tree node or a chrominance coding tree node; determining a division mode of a current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks, wherein the image blocks in the current coding tree node and the adjacent image blocks are spatially adjacent image blocks, the coding information comprises the quadtree depth of the adjacent image blocks and/or the width and height of the adjacent image blocks, and the adjacent image blocks comprise adjacent luminance blocks and/or adjacent chrominance blocks; and dividing the current coding tree node according to the division mode of the coding tree node.

According to the method and the device, the coding information of the adjacent image blocks matched with the type of the current coding unit is selected according to the type of the current coding unit, context modeling is carried out, the dividing mode of the current coding unit is determined, and the current coding tree nodes are divided according to the dividing mode, so that the video coding and decoding efficiency can be improved.

With reference to the second aspect, in some implementation manners of the second aspect, the determining a partition manner of the current coding tree node according to the type of the current coding tree node and/or the coding information of the neighboring image block includes: determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks; and determining the partition mode of the current coding tree node according to the context model number.

With reference to the second aspect, in certain implementations of the second aspect, the determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of neighboring image blocks includes: determining the context model number according to the quadtree depth of the adjacent brightness blocks and the quadtree depth of the current coding tree node under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or determining the context model number according to the quadtree depth of the current coding tree node under the condition that the current coding tree node is the chroma coding tree node.

In this application, when the current coding tree node is a chroma coding tree node, the condL and the condA are preset values, and at this time, the context model corresponding to the syntax element of the current coding unit is unrelated to the quadtree depth of the adjacent image block, so that the complexity of entropy coding and entropy decoding can be reduced, and the video coding and decoding efficiency can be improved.

With reference to the second aspect, in certain implementations of the second aspect, the determining the context model number includes determining the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is the context model number, ctxSetIdx is the number of the context group; when the current coding tree node is a luma chroma coding tree node or a luma coding tree node, the condL indicates whether a quadtree depth of the left neighboring luma block is greater than a quadtree depth of the current coding tree node, the condA indicates whether a quadtree depth of the upper neighboring luma block is greater than a quadtree depth of the current coding tree node, the availableL indicates whether the left neighboring luma block is available, and the availableA indicates whether the upper neighboring luma block is available; or in the case that the current coding unit is a chroma coding unit, the condL is a preset value, the condA is a preset value, the availableL indicates whether the left-side neighboring chroma block is available, and the availableA indicates whether the upper-side neighboring chroma block is available.

With reference to the second aspect, in certain implementations of the second aspect, the syntax element is a split _ qt _ flag that identifies whether the current coding tree node uses quadtree partitioning.

With reference to the second aspect, in certain implementations of the second aspect, the determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of neighboring image blocks includes: determining the context model number according to the width and height of the adjacent brightness blocks and the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or determining the context model number according to the availability of the current coding tree node division mode under the condition that the current coding tree node is a chroma coding unit.

In this application, when the current coding tree node is a chroma coding tree node, the condL and the condA are preset values, and at this time, a context model corresponding to a syntax element of the current coding unit is independent of the width and height of an adjacent image block, so that the complexity of entropy coding and entropy decoding can be reduced, and the video coding and decoding efficiency can be improved.

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is the context model number, ctxSetIdx is the number of the context group; in a case where the current coding tree node is a luma chroma coding tree node or a luma coding tree node, condL indicates whether the width and height of the left-side neighboring luma block are greater than those of the current coding tree node, condA indicates whether the width and height of the upper-side neighboring luma block are greater than those of the current coding tree node, availableL indicates whether the left-side neighboring luma block is available, and availableA indicates whether the upper-side neighboring luma block is available; or in the case that the current coding unit is a chroma coding unit, condL is a predicted value or is determined by the current coding tree node, condA is a preset value, availableL indicates whether the left-side neighboring chroma block is available, and availableA indicates whether the upper-side neighboring chroma block is available.

With reference to the second aspect, in certain implementations of the second aspect, the syntax element is a split cu flag for identifying whether the current coding tree node is partitioned.

In a third aspect, a method for image prediction is provided, the method comprising: determining a context model number corresponding to a syntax element of a current coding unit according to the following formula when the current coding unit is a chroma coding unit:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; the condL indicates whether a prediction mode of the left-side neighboring chroma block is intra block copy prediction, and the condA indicates whether a prediction mode of the upper-side neighboring chroma block is intra block copy prediction; or, the condL and the condA are both preset values; determining a prediction mode of the current coding unit according to the context model number; and predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

In a fourth aspect, a method for partitioning nodes of a coding tree is provided, where the method includes: determining a context model number corresponding to a syntax element of a current coding tree node according to the following formula under the condition that the current coding tree node is a chroma coding tree node:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; both the condL and the condA are preset values; or, the condL is determined by the current coding tree node, and the condA is a preset value; determining the partition mode of the current coding tree node according to the context model number; and dividing the current coding tree node according to the division mode of the coding tree node.

In a fifth aspect, an image prediction apparatus is provided, including: the device comprises a determining module, a judging module and a judging module, wherein the determining module is used for determining the type of a current coding unit, and the type of the current coding unit is a brightness and chrominance coding unit, a brightness coding unit or a chrominance coding unit; the processing module is used for determining the prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of an adjacent image block, wherein the image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block comprises an adjacent luminance block and/or an adjacent chrominance block; and the prediction module is used for predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

According to the image prediction device, the prediction mode of the adjacent image block matched with the type of the current coding unit is selected according to the type of the current coding unit, context modeling is carried out, the prediction mode of the current coding unit is determined, and the image block in the current coding unit is predicted according to the prediction mode, so that the video coding and decoding efficiency can be improved.

With reference to the fifth aspect, in some implementations of the fifth aspect, the processing module is specifically configured to: determining a context model number corresponding to a syntax element of the current coding unit according to the type of the current coding unit and/or a prediction mode of an adjacent image block; and determining the prediction mode of the current coding unit according to the context model number.

With reference to the fifth aspect, in some implementations of the fifth aspect, the processing module is specifically configured to: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or determining condL according to the prediction mode of the left side adjacent chroma block and determining condA according to the prediction mode of the upper side adjacent chroma block when the current coding unit is the chroma coding unit; determining the context model number according to the condL and the condA; wherein the condL and the condA are binary variables.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

With reference to the fifth aspect, in some implementations of the fifth aspect, the processing module is specifically configured to: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or determining the context model number according to a preset condL and a preset condA under the condition that the current coding unit is a chroma coding unit; wherein the condL and the condA are binary variables.

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

With reference to the fifth aspect, in certain implementations of the fifth aspect, the syntax element is pred _ mode _ ibc _ flag, the syntax element is used to identify whether the current coding unit uses intra block copy prediction, the contl is used to indicate whether a prediction mode of a left neighboring image block is intra block copy prediction, and the condA is used to indicate whether a prediction mode of an upper neighboring image block is intra block copy prediction.

In a sixth aspect, an apparatus for partitioning nodes of a coding tree is provided, which includes: the determining module is used for determining the type of a current coding tree node, wherein the type of the current coding tree node is a brightness and chrominance coding tree node, a brightness coding tree node or a chrominance coding tree node; the processing module is used for determining the division mode of the current coding tree node according to the type of the current coding tree node and/or the coding information of the adjacent image blocks, wherein the image blocks in the current coding tree node and the adjacent image blocks are spatially adjacent image blocks, the coding information comprises the quadtree depth of the adjacent image blocks and/or the width and height of the adjacent image blocks, and the adjacent image blocks comprise adjacent luminance blocks and/or adjacent chrominance blocks; and the dividing module is used for dividing the current coding tree node according to the dividing mode of the coding tree node.

According to the coding tree node dividing device, the coding information of the adjacent image blocks matched with the type of the current coding unit is selected according to the type of the current coding unit, context modeling is carried out, the dividing mode of the current coding unit is determined, and the current coding tree nodes are divided according to the dividing mode, so that the video coding and decoding efficiency can be improved.

With reference to the sixth aspect, in some implementations of the sixth aspect, the processing module is specifically configured to: determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks; and determining the partition mode of the current coding tree node according to the context model number.

With reference to the sixth aspect, in some implementations of the sixth aspect, the processing module is specifically configured to: determining the context model number according to the quadtree depth of the adjacent brightness blocks and the quadtree depth of the current coding tree node under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or determining the context model number according to the quadtree depth of the current coding tree node under the condition that the current coding tree node is the chroma coding tree node.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

With reference to the sixth aspect, in certain implementations of the sixth aspect, the syntax element is split _ qt _ flag for identifying whether the current coding tree node uses quadtree partitioning.

With reference to the sixth aspect, in some implementations of the sixth aspect, the processing module is specifically configured to: determining the context model number according to the width and height of the adjacent brightness blocks and the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or determining the context model number according to the availability of the current coding tree node division mode under the condition that the current coding tree node is a chroma coding unit.

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

With reference to the sixth aspect, in certain implementations of the sixth aspect, the syntax element is a split cu flag used to identify whether the current coding tree node is partitioned.

In a seventh aspect, an image prediction apparatus is provided, including: a processing module, configured to determine, when a current coding unit is a chroma coding unit, a context model number corresponding to a syntax element of the current coding unit according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; the condL indicates whether a prediction mode of the left-side neighboring chroma block is intra block copy prediction, and the condA indicates whether a prediction mode of the upper-side neighboring chroma block is intra block copy prediction; or, the condL and the condA are both preset values; the processing module is configured to determine a prediction mode of the current coding unit according to the context model number; and the prediction module is used for predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

In an eighth aspect, there is provided an encoding tree node dividing apparatus, including: a processing module, configured to determine, when a current coding tree node is a chroma coding tree node, a context model number corresponding to a syntax element of the current coding tree node according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; both the condL and the condA are preset values; or, the condL is determined by the current coding tree node, and the condA is a preset value; the processing module is used for determining the partition mode of the current coding tree node according to the context model number; and the dividing module is used for dividing the current coding tree node according to the dividing mode of the coding tree node.

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

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

a video decoder for implementing part or all of the steps of any one of the methods of the first or second or third or fourth aspects.

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

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

In an eleventh aspect, an embodiment of the present application provides an apparatus for encoding video data, including: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform part or all of the steps of any one of the methods of the first or second or third or fourth aspects.

Optionally, the memory is a non-volatile memory.

Optionally, the memory and the processor are coupled to each other.

In a twelfth aspect, an embodiment of the present application provides an apparatus for decoding video data, including: a non-volatile memory and a processor coupled to each other, the processor invoking program code stored in the memory to perform part or all of the steps of any one of the methods of the first or second or third or fourth aspects.

Optionally, the memory is a non-volatile memory.

Optionally, the memory and the processor are coupled to each other.

In a thirteenth aspect, embodiments of the present application provide a computer-readable storage medium storing program code, where the program code includes instructions for performing some or all of the steps of any one of the methods in the first, second, third, or fourth aspects.

In a fourteenth aspect, embodiments of the present application provide a computer program product, which when run on a computer, causes the computer to perform some or all of the steps of any one of the methods of the first aspect, the second aspect, the third aspect or the fourth aspect.

It should be understood that the second to fourteenth aspects of the present application are consistent with the technical solutions of the first aspect of the present application, and similar advantageous effects are obtained in each aspect and the corresponding possible implementation manner, and thus, detailed descriptions are omitted.

It can be seen that, in the present application, according to the type of the current coding unit, the prediction mode of the adjacent image block that matches the type of the current coding unit is selected, context modeling is performed, the prediction mode of the current coding unit is determined, and the image block in the current coding unit is predicted according to the prediction mode, so that video coding and decoding efficiency can be improved.

Drawings

Fig. 1 is a schematic block diagram of an example video encoding system for implementing embodiments of the present application.

Fig. 2 is a schematic block diagram of an example video encoder for implementing embodiments of the present application.

Fig. 3 is a schematic block diagram of an example video decoder for implementing embodiments of the present application.

FIG. 4 is a schematic block diagram of an example video coding system for implementing embodiments of the present application.

FIG. 5 is a schematic block diagram of an example of a video coding apparatus for implementing embodiments of the present application.

Fig. 6 is a schematic block diagram of an example of an encoding apparatus or a decoding apparatus for implementing an embodiment of the present application.

Fig. 7 is a schematic block diagram of a video communication system for implementing an embodiment of the present application.

Fig. 8 is a schematic flowchart of an image prediction method according to an embodiment of the present application.

Fig. 9 is a schematic flowchart of a coding tree node partitioning method according to an embodiment of the present application.

Fig. 10 is a schematic block diagram of an image prediction apparatus according to an embodiment of the present application.

FIG. 11 is a schematic block diagram of an encoding tree node partitioning apparatus according to an embodiment of the present application.

Fig. 12 is a schematic block diagram of another image prediction apparatus according to an embodiment of the present application.

Fig. 13 is a schematic block diagram of another coding tree node division apparatus according to an embodiment of the present application.

Fig. 14 is a schematic block diagram of an image encoding/decoding apparatus of an embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

In the following description, reference is made to the accompanying drawings which form a part hereof and in which is shown by way of illustration specific aspects of embodiments of the application or in which specific aspects of embodiments of the application may be employed. It should be understood that embodiments of the present application may also be used in other respects, 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 equally apply to the corresponding apparatus or system performing the described methods, and vice versa.

For another example, if one or more particular method steps are described, the corresponding apparatus may comprise one or more units, such as functional units, to perform the described one or more method steps (e.g., a unit performs one or more steps, or multiple units, each of which performs one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the figures.

Furthermore, if a particular apparatus is described based on one or more units, such as functional units, the corresponding method may include one step to perform the function of the one or more units (e.g., one step to perform the function of the one or more units, or multiple steps, each of which performs the function of one or more of the plurality of 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 application can be applied to the H.266 standard and the future video coding standard. The terminology used in the description of the embodiments section of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application. Some concepts that may be involved in embodiments of the present application 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 means video encoding or video decoding. Video encoding is performed on the source side, typically including processing (e.g., by compressing) the original video picture to reduce the amount of data required to represent the video picture for more efficient storage and/or transmission. Video decoding is performed at the destination side, typically involving inverse processing with respect to the encoder, to reconstruct the video pictures. Embodiments are directed to video picture "encoding" to be understood as referring to "encoding" or "decoding" of a video sequence. The combination of the encoding part and the decoding part is also called codec (encoding and decoding).

A video sequence comprises a series of images (pictures) which are further divided into slices (slices) which are further divided into blocks (blocks). Video coding performs the coding process 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 is a Macroblock (MB), which may be further divided into a plurality of prediction blocks (partitions) that can be used for predictive coding. In the 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 a brand new tree-based structure is adopted for description. For example, a CU may be partitioned into smaller CUs according to a quadtree, and the smaller CUs may be further partitioned to form a quadtree structure, where the CU is a basic unit for partitioning and encoding an encoded image. There is also a similar tree structure for PU and TU, and PU may correspond to a prediction block, which is the basic unit of predictive coding. The CU is further partitioned into PUs according to a partitioning pattern. A TU may correspond to a transform block, which is a basic unit for transforming a prediction residual. However, CU, PU and TU are basically concepts of blocks (or image blocks).

For example, in HEVC, a CTU is split into multiple CUs by using a quadtree structure represented as a 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 according to 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 obtaining the residual block by applying a 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 used for the CU. In recent developments in video compression technology, coded blocks are partitioned using quad-tree and binary tree (QTBT) partitions to partition frames. In the QTBT block structure, a CU may be square or rectangular in shape.

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

In the case of lossless video coding, the original video picture can 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 the video picture is reduced by performing further compression, e.g., by quantization, while the decoder side cannot fully reconstruct the video picture, 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., the combination of spatial and temporal prediction in the sample domain 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 image block (the current or block to be processed) to obtain a residual block, transforms the residual block and quantizes the residual block in the transform domain to reduce the amount of data to be transmitted (compressed), while the decoder side applies the inverse processing portion relative to the encoder to the encoded or compressed block to reconstruct the current image block for representation. In addition, the encoder replicates the decoder processing loop such that the encoder and decoder generate the same prediction (e.g., intra-prediction and inter-prediction) and/or reconstruction for processing, i.e., encoding, subsequent blocks.

The system architecture to which the embodiments of the present application apply is described below. Referring to fig. 1, fig. 1 schematically shows a block diagram of a video encoding and decoding system 10 to which an embodiment of the present application is applied. As shown in fig. 1, 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 the 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 can include, but is not limited to, a read-only memory (ROM), a Random Access Memory (RAM), an erasable programmable read-only memory (EPROM), a flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures that can be accessed by a computer, as described herein. Source apparatus 12 and destination apparatus 14 may comprise 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, on-board computers, wireless communication devices, or the like.

Although fig. 1 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, source device 12 or corresponding functionality and 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 over 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 a router, switch, base station, or other apparatus that facilitates communication from source apparatus 12 to destination apparatus 14.

Source device 12 includes an encoder 20, and in the alternative, source device 12 may also include a picture source 16, a picture preprocessor 18, and a communication interface 22. In one implementation, the encoder 20, the picture source 16, the picture preprocessor 18, and the communication interface 22 may be hardware components of the source device 12 or may be software programs of the source device 12. Described below, respectively:

the picture source 16, which may include or be any type of picture capturing device, may be used, for example, to capture real-world pictures, and/or any type of picture or comment generating device (for screen content encoding, some text on the screen is also considered part of the picture or image to be encoded), such as a computer graphics processor for generating computer animated pictures, or any type of device for obtaining and/or providing real-world pictures, computer animated pictures (e.g., screen content, Virtual Reality (VR) pictures), and/or any combination thereof (e.g., Augmented Reality (AR) pictures). The picture source 16 may be a camera for capturing pictures or a memory for storing pictures, and the picture source 16 may also include any kind of (internal or external) interface for storing previously captured or generated pictures and/or for obtaining or receiving pictures. When picture source 16 is a camera, picture source 16 may be, for example, an integrated camera local or integrated in the source device; when the picture source 16 is a memory, the picture source 16 may be an integrated memory local or integrated, for example, in the source device. 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.

The picture can be regarded as a two-dimensional array or matrix of pixel elements (picture 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, a picture includes corresponding arrays of red, green, and blue samples. However, in video coding, each pixel is typically represented in a luminance/chrominance format or color space, e.g. for pictures in YUV format, comprising a luminance component (sometimes also indicated with L) indicated by Y and two chrominance components indicated by U and V. The luminance (luma) component Y represents luminance or gray level intensity (e.g., both are the same in a gray scale picture), while the two chrominance (chroma) components U and V represent chrominance or color information components. Accordingly, a picture in YUV format includes a luma sample array of luma sample values (Y), and two chroma sample arrays of chroma values (U and V). Pictures in RGB format can 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 luminance samples. In the embodiment of the present application, the pictures transmitted from the picture source 16 to the picture processor may also be referred to as raw picture data 17.

Picture pre-processor 18 is configured to receive original picture data 17 and perform pre-processing on original picture data 17 to obtain pre-processed picture 19 or pre-processed picture data 19. For example, the pre-processing performed by picture pre-processor 18 may include trimming, color format conversion (e.g., from RGB format to YUV format), toning, or de-noising.

An encoder 20 (or video encoder 20) for receiving the pre-processed picture data 19, processing the pre-processed picture data 19 with a relevant prediction mode (such as the prediction mode in various embodiments herein), thereby providing encoded picture data 21 (structural details of the encoder 20 will be described further below based on fig. 2 or fig. 4 or fig. 5). In some embodiments, the encoder 20 may be configured to perform various embodiments described hereinafter to implement the application of the image prediction method described in the present application on the encoding side.

A communication interface 22, which 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, for example, be used 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 optionally destination device 14 may also include a communication interface 28, a picture post-processor 32, and a display device 34. Described below, respectively:

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 the encoded picture data 21 by way of a link 13 between the source device 12 and the destination device 14, or by way of any type of network, such as a direct wired or wireless connection, 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 a one-way communication interface or a two-way communication interface, and may be used, for example, to send and receive messages to establish a connection, acknowledge and exchange any other information related to a communication link and/or data transfer, such as an encoded picture data transfer.

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

A picture post-processor 32 for performing post-processing on the decoded picture data 31 (also referred to as reconstructed picture data) to obtain post-processed picture data 33. Post-processing performed by picture post-processor 32 may include: color format conversion (e.g., from YUV format to RGB format), toning, trimming 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. Display device 34 may be or may include any type of display for presenting the reconstructed picture, such as an integrated or external display or monitor. For example, the display may include a Liquid Crystal Display (LCD), an Organic Light Emitting Diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), a Digital Light Processor (DLP), or any other display of any kind.

Although source device 12 and destination device 14 are depicted in fig. 1 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, source device 12 or corresponding functionality and 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.

It will be apparent to those skilled in the art from this description that the existence and (exact) division of the functionality of the different elements or source device 12 and/or destination device 14 shown in fig. 1 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, a mobile phone, a smartphone, a tablet or tablet computer, a camcorder, a desktop computer, a set-top box, a television, a camera, an in-vehicle device, a display device, a digital media player, a video game console, a video streaming device (e.g., a content service server or a content distribution server), a broadcast receiver device, a broadcast transmitter device, etc., and may not use or use any type of operating system.

Both encoder 20 and decoder 30 may be implemented as any of a variety of suitable circuits, such as one or more microprocessors, Digital Signal Processors (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, the device 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 application. Any of the foregoing, including hardware, software, a combination of hardware and software, etc., may be considered as one or more processors.

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

Referring to fig. 2, fig. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing embodiments of the present application. 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 (DPB) 230, a prediction processing unit 260, and an entropy encoding unit 270. Prediction processing unit 260 may include inter prediction unit 244, intra prediction unit 254, and mode selection unit 262. 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, and, 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 (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 a signal path of a decoder (see the decoder 30 in fig. 3).

The encoder 20 receives, e.g., via an input 202, a picture 201 or an image block 203 of a picture 201, e.g., a picture in a sequence of pictures forming a video or a video sequence. 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 the current picture is distinguished 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 the encoder 20 may comprise a partitioning unit (not shown in fig. 2) for partitioning the picture 201 into a plurality of blocks, e.g. image blocks 203, typically into a plurality of non-overlapping blocks. The partitioning unit may be used to use the same block size for all pictures in a 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 partition 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 segmentation techniques.

Like picture 201, image block 203 is also or can be considered as a two-dimensional array or matrix of sample points having sample values, although its size is smaller than picture 201. In other words, the image block 203 may comprise, for example, one sample array (e.g., a luma array in the case of a black and white picture 201) or three sample arrays (e.g., a luma array and two chroma 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 to encode a picture 201 block by block, e.g. 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), e.g. by subtracting sample values of the prediction block 265 from sample values of the picture image block 203 sample by sample (pixel by pixel) to obtain the residual block 205 in the sample domain.

The transform processing unit 206 is configured to apply a transform, such as a Discrete Cosine Transform (DCT) or a Discrete Sine Transform (DST), on the sample values of the residual block 205 to obtain transform coefficients 207 in a 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 transform specified for HEVC/h.265. Such integer approximations are typically scaled by some factor compared to the orthogonal DCT transform. To maintain the norm of the residual block processed by the forward transform and the inverse transform, an additional scaling factor is applied as part of the transform process. The scaling factor is typically selected based on certain constraints, e.g., the scaling factor is a power of 2 for a shift operation, a trade-off between bit depth of transform coefficients, accuracy and implementation cost, etc. For example, a specific scaling factor may be specified on the decoder 30 side for the inverse transform by, for example, inverse transform processing unit 212 (and on the encoder 20 side for the corresponding inverse transform by, for example, inverse transform processing unit 212), and correspondingly, a corresponding scaling factor may be specified on the encoder 20 side for the forward transform by transform processing unit 206.

Quantization unit 208 is used to quantize transform coefficients 207, e.g., by applying scalar quantization or vector quantization, to obtain quantized transform coefficients 209. 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 transform coefficients 207. For example, an n-bit transform coefficient may be rounded down to an m-bit transform coefficient during quantization, where n is greater than m. The quantization level may be modified by adjusting a Quantization Parameter (QP). For example, for scalar quantization, different scales may be applied to achieve finer or coarser quantization. Smaller quantization steps correspond to finer quantization and larger quantization steps correspond to coarser quantization. An appropriate quantization step size may be indicated by a Quantization Parameter (QP). For example, the quantization parameter may be an index of a predefined set of suitable quantization step sizes. For example, a smaller quantization parameter may correspond to a fine quantization (smaller quantization step size) and a larger quantization parameter may correspond to a coarse quantization (larger quantization step size), or vice versa. The quantization may comprise a division by a quantization step size and a corresponding quantization or inverse quantization, e.g. performed by inverse quantization 210, or may comprise a multiplication by a quantization step size. Embodiments according to some standards, such as HEVC, may use a quantization parameter to determine the quantization step size. In general, the quantization step size may be calculated based on the quantization parameter using a fixed point approximation of an equation that includes division. Additional scaling factors may be introduced for quantization and dequantization to recover the norm of the residual block that may be modified due to the scale used in the fixed point approximation of the equation for the quantization step size and quantization parameter. In one example implementation, the inverse transform and inverse quantization scales 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 greater 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., to apply an inverse quantization scheme of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step as the quantization unit 208. The dequantized coefficients 211 may also be referred to as dequantized residual coefficients 211, corresponding to transform coefficients 207, although the loss due to quantization is typically not the same as 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 (DCT) or an inverse 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 transform dequantized block 213 or an inverse transform residual block 213.

The reconstruction unit 214 (e.g., 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 (or simply "buffer" 216), such as a line buffer 216, is used to buffer or store the reconstructed block 215 and corresponding sample values, for example, for intra prediction. In other embodiments, the encoder may be used to use the unfiltered reconstructed block and/or corresponding sample values stored in buffer unit 216 for any class of estimation and/or prediction, such as intra prediction.

For example, an embodiment 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 filtered block 221 and/or blocks or samples from decoded picture buffer 230 (neither shown in fig. 2) as input or basis for 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, so as to facilitate pixel transition or improve video quality. Loop filter unit 220 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 (ALF), or a sharpening or smoothing filter, or a collaborative filter. 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. The decoded picture buffer 230 may store the reconstructed encoded block after the loop filter unit 220 performs a filtering operation on the reconstructed encoded block.

Embodiments of encoder 20 (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 (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 from any of a variety of memory devices, such as Dynamic Random Access Memory (DRAM) including Synchronous DRAM (SDRAM), Magnetoresistive RAM (MRAM), Resistive RAM (RRAM), or other types of memory devices. The DPB 230 and the buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, a Decoded Picture Buffer (DPB) 230 is used to store filtered blocks 221. Decoded picture buffer 230 may further be used to store other previous filtered blocks, such as previous reconstructed and filtered blocks 221, of the same current picture or of a different picture, such as a previous reconstructed picture, and may provide the complete previous reconstructed, i.e., decoded picture (and corresponding reference blocks and samples) and/or the partially reconstructed current picture (and corresponding reference blocks and samples), e.g., for inter prediction. In a certain example, if reconstructed block 215 is reconstructed without in-loop filtering, Decoded Picture Buffer (DPB) 230 is used to store reconstructed block 215.

Prediction processing unit 260, also referred to as block prediction processing unit 260, is used to receive or obtain image block 203 (current image block 203 of current picture 201) and reconstructed picture data, e.g., reference samples of the same (current) picture from buffer 216 and/or reference picture data 231 of one or more previously decoded pictures from decoded picture buffer 230, and to process such data for prediction, i.e., to provide prediction block 265, which may be inter-predicted block 245 or 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 prediction modes (e.g., from those supported by prediction processing unit 260) that provide the best match or the smallest residual (smallest residual means better compression in transmission or storage), or that provide the smallest signaling overhead (smallest signaling overhead means better compression in transmission or storage), or both. The mode selection unit 262 may be configured to determine a prediction mode based on Rate Distortion Optimization (RDO), i.e., select a prediction mode that provides the minimum rate distortion optimization, or select a prediction mode in which the associated rate distortion at least meets the prediction mode selection criteria.

The prediction processing performed by the example of the encoder 20 (e.g., by the prediction processing unit 260) and the mode selection performed (e.g., by the 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 set of (predetermined) prediction modes. The prediction mode set may include, for example, intra prediction modes and/or inter prediction modes.

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

In a possible implementation, the set of inter prediction modes may for example comprise an Advanced Motion Vector (AMVP) mode and a merge (merge) mode depending on available reference pictures (i.e. at least partially decoded pictures stored in the DBP230, for example, as described above) and other inter prediction parameters, for example depending on whether the best matching reference block is searched using the entire reference picture or only a portion of the reference picture, for example, a search window region of a region surrounding the current image block, and/or depending on whether pixel interpolation, such as half-pixel and/or quarter-pixel interpolation, is applied. In a specific implementation, the inter prediction mode set may include an improved control point-based AMVP mode and an improved control point-based merge mode according to an embodiment of the present application. 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 mode, embodiments of the present application may also apply a skip mode and/or a direct mode.

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

The inter prediction unit 244 may include a Motion Estimation (ME) unit (not shown in fig. 2) and a 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 comprise 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 forming the video sequence.

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

The motion compensation unit is configured to obtain inter-prediction parameters and perform inter-prediction based on or using the inter-prediction parameters to obtain an inter-prediction block 245. The motion compensation performed by the motion compensation unit (not shown in fig. 2) may involve taking or generating a prediction block based on a motion/block vector determined by motion estimation (possibly performing interpolation to sub-pixel precision). Interpolation filtering may generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks that may be used to encode 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 in one reference picture list to which the motion vector points. Motion compensation unit 246 may also generate syntax elements associated with the blocks and video slices for use by decoder 30 in decoding picture blocks of the video slices.

Specifically, the inter prediction unit 244 may transmit a syntax element including an inter prediction parameter (e.g., indication information for selecting an inter prediction mode for current image block prediction after traversing a plurality of inter prediction modes) to the entropy encoding unit 270. In a possible application scenario, if there is only one inter prediction mode, the inter prediction parameters may not be carried in the syntax element, and the decoding end 30 can directly use the default prediction mode for decoding. It will be 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) of the same picture and one or more previously reconstructed blocks, e.g., reconstructed neighboring blocks, to be received for intra estimation. For example, the 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., an intra prediction mode that provides a prediction block 255 that is most similar to current picture block 203) or a minimum code rate distortion.

The intra-prediction unit 254 is further configured to determine the intra-prediction block 255 based on the intra-prediction parameters as the selected intra-prediction mode. In any case, after selecting the intra-prediction mode for the block, intra-prediction unit 254 is also used to provide intra-prediction parameters, i.e., information indicating the selected intra-prediction mode for the block, to 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 (e.g., indication information for selecting an intra prediction mode for current image 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 parameters may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding.

Entropy encoding unit 270 is configured to apply an entropy encoding algorithm or scheme (e.g., a Variable Length Coding (VLC) scheme, a Context Adaptive VLC (CAVLC) scheme, an arithmetic coding scheme, a Context Adaptive Binary Arithmetic Coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), Probability Interval Partitioning Entropy (PIPE) coding, or other entropy encoding methods or techniques) to individual or all of 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 output 272 in the form of, for example, 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 quantize the residual signal directly without the transform processing unit 206 for certain blocks or frames. In another embodiment, encoder 20 may have quantization unit 208 and inverse quantization unit 210 combined into a single unit.

Specifically, in the embodiment of the present application, the encoder 20 may be used to implement the video encoding process described in the following embodiments.

It should be understood that the video encoder in the present application may include only a part of the modules in the video encoder 20, for example, the video encoder in the present application may include an image decoding unit and a dividing unit. Wherein the image decoding unit may be composed of one or more units of an entropy decoding unit, a prediction unit, an inverse transform unit, and an inverse quantization unit.

In addition, other structural changes 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 quantize the residual signal directly without processing by transform processing unit 206 and, correspondingly, without processing by inverse transform processing unit 212; alternatively, for some image blocks or image frames, the video encoder 20 does not generate residual data and accordingly does not need to be processed by the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, and the inverse transform processing unit 212; alternatively, video encoder 20 may store the reconstructed image block directly as a reference block without processing by filter 220; alternatively, the quantization unit 208 and the inverse quantization unit 210 in the video encoder 20 may be merged together. The loop filter 220 is optional, and in the case of lossless compression coding, the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, and the inverse transform processing unit 212 are optional. It should be appreciated that the inter prediction unit 244 and the intra prediction unit 254 may be selectively enabled according to different application scenarios.

Referring to fig. 3, fig. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing embodiments of the present application. Video decoder 30 is operative to receive encoded picture data (e.g., an encoded bitstream) 21, e.g., encoded by encoder 20, to obtain a 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 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), such as any or all of inter-prediction, intra-prediction parameters, loop filter parameters, and/or other syntax elements (decoded). The entropy decoding unit 304 is further for forwarding the inter-prediction parameters, the intra-prediction parameters, and/or other syntax elements to the prediction processing unit 360. Video decoder 30 may receive syntax elements at the video slice 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.

Prediction processing unit 360 may include inter prediction unit 344 and intra prediction unit 354, where inter prediction unit 344 may be functionally similar to inter prediction unit 244 and intra prediction unit 354 may be functionally similar to 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 (explicitly or implicitly) prediction related parameters and/or information about the selected prediction mode from, for example, the entropy decoding unit 304.

When the video slice is encoded as an intra-coded (I) slice, intra-prediction unit 354 of prediction processing unit 360 is used to generate a prediction block 365 for the picture block of the current video slice based on the signaled intra-prediction mode and data from previously decoded blocks of the current frame or picture. When a video frame is encoded as an inter-coded (i.e., B or P) slice, inter prediction unit 344 (e.g., a motion compensation unit) of prediction processing unit 360 is used to generate a prediction block 365 for the video block of the current video slice based on the motion vectors 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 the reference frame list using default construction techniques based on the reference pictures stored in DPB 330: list 0 and list 1.

Prediction processing unit 360 is used to determine prediction information for the video blocks of the current video slice by parsing the motion vectors and other syntax elements, and to generate a prediction block for the current video block being decoded using the prediction information. In an example of the present application, prediction processing unit 360 uses some of the 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, a motion vector for each inter-coded video block of the slice, an inter prediction state for each inter-coded video block of the slice, and other information to decode video blocks of a current video slice. In another example of the present application, the syntax elements received by video decoder 30 from the bitstream include syntax elements received in one or more of an Adaptive Parameter Set (APS), a Sequence Parameter Set (SPS), a 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 the video slice to determine the degree of quantization that should be applied and likewise the degree of inverse quantization that should be applied.

Inverse transform processing unit 312 is used 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 produce a block of residuals in the pixel domain.

The reconstruction unit 314 (e.g., summer 314) is used to add the inverse transform block 313 (i.e., reconstructed residual block 313) to the prediction block 365 to obtain the 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 (either during or after the encoding cycle) is used to filter reconstructed block 315 to obtain filtered block 321 to facilitate 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 (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.

Decoded video block 321 in a given frame or picture is then stored in decoded picture buffer 330, which stores reference pictures for subsequent motion compensation.

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

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

Specifically, in the embodiment of the present application, the decoder 30 is used to implement the video decoding method described in the following embodiments.

It should be understood that the video encoder in the present application may include only a part of the modules in the video encoder 30, for example, the video encoder in the present application may include a partition unit and an image encoding unit. Wherein the image encoding unit may be composed of one or more units of a prediction unit, a transform unit, a quantization unit, and an entropy encoding unit.

In addition, 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 quantized coefficients are not decoded by entropy decoding unit 304 of video decoder 30 and, accordingly, do not need to be processed by inverse quantization unit 310 and inverse transform processing unit 312. Loop filter 320 is optional; and the inverse quantization unit 310 and the inverse transform processing unit 312 are optional for the case of lossless compression. It should be understood 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 the 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 clamped (clip) or shifted (shift).

For example, the motion vector of the control point of the current image block derived according to the motion vector of the adjacent affine coding block (the coding block predicted by using the affine motion model may be referred to as an affine coding block), or the motion vector of the sub-block of the current image block derived may be further processed, which is not limited in this application. For example, the value range of the motion vector is constrained to be within a certain bit width. Assuming that the allowed bit-width of the motion vector is bitDepth, the motion vector ranges from-2 ^ (bitDepth-1) to 2^ (bitDepth-1) -1, where the "^" symbol represents the power. And if the bitDepth is 16, the value range is-32768-32767. And if the bitDepth is 18, the value range is-131072-131071.

As another example, the value of the motion vector (e.g., the motion vector MV of four 4x4 sub-blocks within an 8x8 image block) may be constrained such that the maximum difference between the integer parts of the four 4x4 sub-blocks MV does not exceed N (e.g., N may be 1) pixels.

Referring to fig. 4, fig. 4 is an illustrative diagram 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 the embodiments of the present application. In the illustrated embodiment, video coding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video codec implemented by logic 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. 4, 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 instances, antenna 42 may be used to transmit or receive an encoded bitstream of video data. Additionally, in some instances, 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. Video decoding system 40 may also include an optional processor 43, which optional processor 43 similarly may include application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, or the like. In some examples, the logic 47 may be implemented in hardware, such as video encoding specific hardware, and the processor 43 may be implemented in general purpose software, an operating system, and so on. In addition, the memory 44 may be any type of memory, such as a volatile memory (e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), etc.) or a non-volatile memory (e.g., flash memory, etc.), and so on. In a non-limiting example, storage 44 may be implemented by a speed cache memory. In some instances, logic circuitry 47 may access memory 44 (e.g., to implement an image buffer). In other examples, logic 47 and/or processing unit 46 may include memory (e.g., cache, etc.) for implementing image buffers, 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 an 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 by logic circuitry 47 in a similar manner 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, logic circuit implemented decoder 30 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 a decoder 30 implemented by logic circuitry 47 to implement the various modules discussed with reference to fig. 3 and/or any other decoder system or subsystem described herein.

In some instances, 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 encoding partition (e.g., transform coefficients or quantized transform coefficients, (as discussed) optional indicators, and/or data defining the encoding partition). 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 for the example described with reference to encoder 20 in the embodiments of the present application, decoder 30 may be used to perform the reverse process. With respect to 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 instances, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a video coding apparatus 400 (e.g., a video encoding apparatus 400 or a video decoding apparatus 400) provided by an embodiment of the present application. Video coding apparatus 400 is suitable for implementing the embodiments described herein. In one embodiment, video coding device 400 may be a video decoder (e.g., decoder 30 of fig. 3) or a video encoder (e.g., encoder 20 of fig. 2). In another embodiment, video coding device 400 may be one or more components of decoder 30 of fig. 3 or encoder 20 of fig. 2 described above.

Video coding apparatus 400 includes: an ingress port 410 and a reception 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. Video coding device 400 may also include optical-to-Electrical (EO) components and optical-to-electrical (opto) components coupled with ingress port 410, receiver unit 420, transmitter unit 440, and egress port 450 for egress or ingress of optical or electrical signals.

The processor 430 is implemented by 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. Processor 430 includes a coding module 470 (e.g., encoding module 470 or decoding module 470). The encoding/decoding module 470 implements embodiments disclosed herein to implement the image prediction methods provided by embodiments of the present application. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations. Accordingly, substantial improvements are provided to the functionality of the video coding apparatus 400 by the encoding/decoding module 470 and affect the transition of the video coding apparatus 400 to different states. Alternatively, the encode/decode module 470 is implemented as instructions stored in the memory 460 and executed by the processor 430.

The memory 460, which may include one or more disks, tape drives, and solid state drives, may be used as an over-flow data storage device for storing programs when such programs are selectively executed, and for storing instructions and data that are read during program execution. The 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. 6, fig. 6 is a simplified block diagram of an apparatus 500 that may be used as either or both of source device 12 and destination device 14 in fig. 1 according to an example embodiment. The apparatus 500 may implement the image prediction method of the embodiment of the present application. In other words, fig. 6 is a schematic block diagram of one implementation of an encoding apparatus or a decoding apparatus (simply referred to as a decoding apparatus 500) of the embodiment of the present application. Among other things, the decoding device 500 may include a processor 510, a memory 530, and a bus system 550. Wherein 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 coding 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, and in particular the various new image block partitioning methods. To avoid repetition, it is not described in detail here.

In the embodiment of the present application, the processor 510 may be a Central Processing Unit (CPU), and the processor 510 may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and so on. 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 memory device may also be used for memory 530. Memory 530 may include code and data 531 to be accessed by processor 510 using bus 550. Memory 530 may further include an operating system 533 and application programs 535, the application programs 535 including at least one program that allows processor 510 to perform the video encoding or decoding methods described herein. For example, the application programs 535 may include applications 1 through N, which further include a video encoding or decoding application (simply a video coding application) that performs the video encoding or decoding methods described herein.

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, however, the various buses are designated in the figure as bus system 550.

Optionally, the translator 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 the processor 510 via the bus 550.

Fig. 7 is a schematic block diagram of a video communication system of an embodiment of the present application.

The video communication system 500 shown in fig. 7 includes a source device 600 and a destination device 700, where the source device 600 can encode an acquired video and transmit an encoded video stream to the receiving device 700, and the destination device 700 can parse the received video stream to obtain a video image and display the video via a display device.

The image prediction method of the embodiment of the present application can be applied to entropy encoding processing of a video encoder or entropy decoding processing of a video decoder. As shown in fig. 7, the image prediction method of the embodiment of the present application may be performed by the source device 600 or the destination device 700. Specifically, the image prediction method of the embodiment of the present application may be performed by the video encoder 603 or the video decoder 702.

The video communication system 500 may also be referred to as a video codec system, the source device 600 may also be referred to as a video encoding device or a video encoding apparatus, and the destination device 700 may also be referred to as a video decoding device or a video decoding apparatus.

In fig. 7, source device 600 includes a video capture device 601, video memory 602, video encoder 603, and transmitter 604. Video memory 602 may store video obtained by video capture device 601, and video encoder 603 may encode video data from video memory 602 and video capture device 601. In some examples, source device 600 transmits the encoded video data directly to destination device 700 via transmitter 604. The encoded video data may also be stored on a storage medium or file server for later extraction by destination device 700 for decoding and/or playback.

In fig. 7, destination device 700 includes a receiver 701, a video decoder 702, and a display device 703. In some examples, receiver 701 may receive encoded video data over channel 800. Display device 703 may be integrated with destination device 700 or may be external to destination device 7000. In general, the display device 700 displays decoded video data. The display device 700 may include a variety of display devices such as a liquid crystal display, a plasma display, an organic light emitting diode display, or other types of display devices.

The source apparatus 600 and the destination apparatus 700 may be implemented in any one of the following devices: a desktop computer, a mobile computing device, a notebook (e.g., laptop) computer, a tablet computer, a set-top box, a smartphone, a handset, a television, a camera, a display device, a digital media player, a video game console, an on-board computer, or other similar apparatus.

Destination device 700 may receive encoded video data from source device 600 via channel 800. Channel 800 may include one or more media and/or devices capable of moving encoded video data from source device 600 to destination device 700. In one example, channel 800 may include one or more communication media that enable source device 600 to transmit encoded video data directly to destination device 700 in real-time, in which case source device 600 may modulate the encoded video data according to a communication standard (e.g., a wireless communication protocol) and may transmit the modulated video data to destination device 700. The one or more communication media may comprise 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 comprise a router, switch, base station, or other device that enables communication from source device 600 to destination device 700.

In another example, channel 800 may include a storage medium that stores encoded video data generated by source device 600. In this example, destination device 700 may access the storage medium via disk access or card access. The storage medium may comprise a variety of locally-accessible data storage media such as a blu-ray disc, a Digital Video Disc (DVD), a compact disc read-only memory (CD-ROM), flash memory, or other suitable digital storage medium for storing encoded video data.

In another example, channel 800 may include a file server or another intermediate storage device that stores encoded video data generated by source device 600. In this example, destination device 700 may access encoded video data stored at a file server or other intermediate storage device via streaming or download. The file server may be of a type capable of storing encoded video data and transmitting the encoded video data to the destination device 700. For example, the file server may include a world wide Web (Web) server (e.g., for a website), a File Transfer Protocol (FTP) server, a Network Attached Storage (NAS) device, and a local disk drive.

Destination device 700 may access the encoded video data via a standard data connection, such as an internet connection. Example types of data connections include a wireless channel, a wired connection (e.g., cable modem, etc.), or a combination of both, suitable for accessing encoded video data stored on a file server. The transmission of the encoded video data from the file server may be a streaming transmission, a download transmission, or a combination of both.

Context-based adaptive binary arithmetic coding (CABAC) is a commonly used entropy coding technique for coding and decoding syntax element values, and is applied in standards such as h.264/AVC, h.265/HEVC, and h.266/VVC.

The entropy coding process, taking a general mode (regular mode) in HEVC as an example, mainly includes three steps:

(1) binarizing a syntax element into one or more binary bins (bins), each bin taking the value 0 or 1;

(2) for each bit, determining a context model for the bit based on context information (e.g., coding information in a reconstructed region around the corresponding node of the syntax element);

(3) and coding the bit according to the probability value in the context model of the bit, and updating the probability value in the context model according to the value of the bit.

Accordingly, the entropy decoding process mainly includes three steps:

(1) for each bit, determining a context model for the bit based on context information (e.g., coding information in a reconstructed region around the corresponding node of the syntax element);

(2) decoding the bit according to the probability value in the context model, and updating the probability value in the context model according to the value of the bit;

(3) and obtaining the value of the syntax element according to the value of the one or more bits obtained by decoding.

The process of determining the context model of the bits according to the context information may also be referred to as context modeling. Generally, the context modeling method is the same during the encoding process and the decoding process.

The bit obtained by binarizing the syntax element may be referred to as a bit corresponding to the syntax element, and the context model of the bit refers to a context model of the bit corresponding to the syntax element. For convenience of understanding, the context model of the bit corresponding to the syntax element is referred to as the context model corresponding to the syntax element.

In the VTM5, there may be multiple context models corresponding to one syntax element, for example, 2, 3, 6 or 9 context models may be provided for one syntax element according to the difference of the coding information of the surrounding blocks, such syntax elements include split _ cu _ flag, split _ qt _ flag, cu _ skip _ flag, pred _ mode _ flag and pred _ mode _ ibc _ flag, and the coding process and the decoding process determine the context model number corresponding to the syntax element of the current coding unit according to the coding information of the neighboring image blocks of the current coding unit.

In HEVC, a luma block and a chroma block of a coding tree node are divided into sub-nodes using the same division method, which is called a single tree (single tree) division structure, and thus, one coding unit includes luma pixels and chroma pixels. In VTM5, a split tree (partition tree) partition structure is allowed for an intra picture (I picture), and at this time, starting from a certain node a on the coding tree, a luminance block of the node a may be partitioned by a luminance coding tree (luma coding tree), and a leaf node of the luminance coding tree is a luminance coding unit (luma CU), which only contains luminance pixels; the chroma block of node a may be partitioned by a chroma coding tree (chroma coding tree), whose leaf nodes are chroma coding units (chroma CUs), which only contain chroma pixels.

For a single tree partition structure, the coding information of a luminance block at any one position and the coding information of a chrominance block at that position are the same; for the split tree partition structure, there may be a case where the coding information of the luma block at a location is different from the coding information of the chroma block at the location, for example, the prediction MODE of the luma block at a location is INTRA block copy prediction MODE (MODE _ IBC) and the prediction MODE of the chroma block at the location is INTRA prediction MODE (MODE _ INTRA); as another example, a luminance block at a location is 4 wide, while a chrominance block at that location is 16 wide; for another example, the quad-tree depth of a luminance block at a position is 3, and the quad-tree depth of a chrominance block at the position is 1.

In VTM5, context model number determination of pred _ MODE _ IBC _ flag of chroma coding unit means that MODE for luma block of left neighboring block, condL, and MODE _ IBC, respectively.

Therefore, in the case where the current coding unit is a chroma coding unit, the context model number of the current coding unit is determined using the coding information of the neighboring luma blocks in the coding process and the decoding process, resulting in low coding efficiency.

In order to solve the above problems, the present application provides an image prediction method, which can improve the compression efficiency of video encoding and decoding, thereby improving the encoding and decoding efficiency.

The image prediction method according to the embodiment of the present application is described in detail below with reference to the specific drawings.

Fig. 8 is a schematic flowchart of an image prediction method according to an embodiment of the present application. The image prediction method shown in fig. 8 may be performed by an image prediction apparatus (which may be located in an image decoding apparatus (system) or an image encoding apparatus (system)), and specifically, the method shown in fig. 8 may be performed by the image encoding apparatus or the image decoding apparatus. The method illustrated in fig. 8 may be performed at the encoding end or the decoding end, and the method 800 illustrated in fig. 8 includes

steps

810, 820, and 830, which are described in detail below.

And S810, determining the type of the current coding unit.

The type of the current coding unit may be a luma chroma coding unit, a luma coding unit, or a chroma coding unit. The luma-chroma coding unit refers to a coding unit including a luma block and a chroma block, the luma coding unit refers to a coding unit including a luma block, and the chroma coding unit refers to a coding unit including a chroma block.

S820, determining the prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of the adjacent image block.

Wherein the image block and the adjacent image block in the current coding unit are spatially adjacent image blocks, and the adjacent image blocks include adjacent luminance blocks and/or adjacent chrominance blocks.

Optionally, the determining the prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of the neighboring image block may include: determining a context model number corresponding to a syntax element of the current coding unit according to the type of the current coding unit and/or a prediction mode of an adjacent image block; and determining the prediction mode of the current coding unit according to the context model number.

The context model number may be represented by ctxInc, and the context model number ctxInc may be determined by the following formula (1), for example.

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3(1)

Wherein availableL ═ 1 indicates that the left-side neighboring image block of the current coding unit is available, and availableL ═ 0 indicates that the left-side neighboring image block of the current coding unit is not available; availableA ═ 1 indicates that the upper adjacent image block of the current coding unit is available, and availableA ═ 0 indicates that the upper adjacent image block of the current coding unit is not available. contl and condA are binary variables, that is, contl and condA take values of 0 or 1, the contl is used to indicate whether the prediction mode of the left adjacent image block is intra block copy prediction, the condA is used to indicate whether the prediction mode of the upper adjacent image block is intra block copy prediction, ctxSetIdx is the number of the context group, ctxSetIdx may be 0, or ctxSetIdx may be determined by the encoding information of the current encoding unit.

The prediction modes in VTM5 include three types: an INTRA prediction MODE (MODE _ INTRA), an INTER prediction MODE (MODE _ INTER), and an INTRA block copy prediction MODE (MODE _ IBC).

The adjacent image blocks may be: the image block has been decoded and is within a video image; the adjacent image blocks may not mean: the image block is not decoded or is not within the video image. Whether an image block is available in different video coding standards may also include other constraints, such as in HEVC, where neighboring image blocks are also considered impossible if the image block and the neighboring image block are not within the same stripe.

When ctxSetIdx corresponding to a syntax element is 0, the formula (1) can be simplified to the following formula (2), and at this time, it can be determined through the above formula (2) that the context model number ctxInc has only three values, i.e., 0, 1, and 2.

ctxInc＝(condL&&availableL)+(condA&&availableA) (2)

In this application, the syntax element may be pred _ mode _ ibc _ flag, and the syntax element may be used to identify whether the current coding unit uses intra block copy prediction, and accordingly, ctxSetIdx corresponding to the syntax element is 0.

Wherein, the meanings of condL, condA, availableL and availableA in formula (2) are the same as those in formula (1), and are not described herein again.

In the present application, the method for determining the context model number according to the type of the current coding unit may specifically include the following two methods.

The method comprises the following steps:

in the case where the current coding unit is a luma chroma coding unit or a luma coding unit, condL may be determined according to a prediction mode of a left-side adjacent luma block, and condA may be determined according to a prediction mode of an upper-side adjacent luma block; the context model number may be determined from the condL and the condA;

in the case where the current coding unit is a chroma coding unit, condL may be determined according to a prediction mode of a left-side neighboring chroma block and condA may be determined according to a prediction mode of an upper-side neighboring chroma block; the context model number may be determined from the condL and the condA;

wherein, the condL and the condA are binary variables, and values are, for example, 0 and 1.

For example, in method one, condL and condA can be determined by equation (1) above.

In the case where the syntax element of the current coding unit is pred _ mode _ ibc _ flag, ctxSetIdx may be 0, and at this time, condL and condA may be determined by the above equation (2).

The value of codl may be a decision result of CuPredMode [ chType ] [ xNbL ] [ yNbL ] ═ MODE _ IBC, where CuPredMode [ chType ] [ xNbL ] [ yNbL ] ═ MODE _ IBC indicates that a prediction MODE of a left-side adjacent image block (xNbL, yNbL) is intra block copy prediction, that is, when CuPredMode [ chType ] [ xNbL ] [ yNbL ] ═ MODE _ IBC is true, the value of codl is 1, and when CuPredMode [ chType ] [ xNbL ] [ yNbL ] ═ MODE _ IBC is false, the value of codl is 0;

the value of the condA may be a result of determining that CuPredMode [ chType ] [ xNbA ] [ yNbA ] ═ MODE _ IBC, where CuPredMode [ chType ] [ xNbA ] [ yNbA ] ═ MODE _ IBC indicates that the prediction MODE of the left-side adjacent image block (xNbA, yNbA) is intra block copy prediction, that is, when CuPredMode [ chType ] [ xNbA ] [ yNbA ], (yNbA ] ═ MODE _ IBC is true, the value of the condA is 1, and when CuPredMode [ chType ] [ xNbA ] [ yNbA ], (MODE _ IBC) is false, the value of the condA is 0;

wherein, (xNbL, yNbL) represents the position of the left adjacent image block in the video picture, (xNbA, yNbA) represents the position of the upper adjacent image block in the video picture, CuPredMode [1] [ x ] [ y ] represents the prediction mode of the chroma block with coordinate position (x, y), CuPredMode [0] [ x ] [ y ] represents the prediction mode of the luma block with coordinate position (x, y), ctxSetIdx is the number of the context group, and chType is determined by the current coding unit type. For example, the chType may be 1 in the case where the current coding unit is a chroma coding unit, and may be 0 in the case where the current coding unit is a luma chroma coding unit or a luma coding unit.

Alternatively, the coordinates of the upper left corner of the current coding unit in the video image are (x0, y0), the width of the current coding unit is cbWidth, the height of the current coding unit is cbHeight, and the unit of luminance pixel is taken as the unit, then the coordinates of the image block (xNbL, yNbL) adjacent to the left side can be (x0-1, y0), and the coordinates of the image block (xNbA, yNbA) adjacent to the upper side can be (x0, y 0-1); alternatively, the coordinates of the left-side adjacent image block (xNbL, yNbL) may be (x0-1, y0+ cbHeight/2), and the coordinates of the left-side adjacent image block (xNbA, yNbA) may be (x0+ cbWidth/2, y 0-1).

In summary, in the first method, according to the type of the current coding block and the above formula (1) or formula (2), the context model number ctxInc corresponding to the syntax element of the current coding unit can be determined.

The second method comprises the following steps:

in a case that the current coding unit is a chroma coding unit, the condL and the condA may be preset values; the context model number may be determined from condL and condA;

wherein the condL and the condA are binary variables.

For example, in the second method, in the case that the current coding unit is a luma chroma coding unit or a luma coding unit, condL and condA may be determined by the above formula (1).

The value of contl may be a decision result of cuppredmode [ xNbL ] [ yNbL ] ═ MODE _ IBC, where cuppredmode [ xNbL ] [ yNbL ] ═ MODE _ IBC indicates that the prediction MODE of the left adjacent image block (xNbL, yNbL) is the intra block copy prediction MODE, that is, when cuppredmode [ xNbL ] [ yNbL ] ═ MODE _ IBC is true, the value of contl is 1, and when cuppredmode [ xNbL ] [ yNbL ] ═ MODE _ IBC is false, the value of contl is 0;

the value of the condA may be a decision result of cuppredmode [ xNbA ] [ yNbA ] ═ MODE _ IBC, and the prediction MODE in which cuppredmode [ xNbA ] [ yNbA ] ═ MODE _ IBC indicates that the left adjacent image block (xNbA, yNbA) is the intra block copy prediction MODE, that is, when cuppredmode [ xNbA ] [ yNbA ] - (MODE _ IBC is true, the value of the condA is 1, and when cuppredmode [ xNbA ] [ yNbA ] - (MODE _ IBC is false, the value of the condA is 0.

The descriptions of the other variables (or parameters) in equations (1) and (2) are similar to the method one, and are not repeated here.

In the case that the current coding unit is a chroma coding unit, condL and condA may be preset values.

For example, both condL and condA may be set to 0. At this time, if ctxSetIdx is 0, it can be seen from the above equation (2) that the context model number ctxInc corresponding to the syntax element of the current coding unit is also 0.

That is, when the current coding unit is a chroma coding unit, the context model number ctxInc is set to 0 in advance.

It should be understood that the above examples are only exemplary and not limiting, and that condL and condA may be set to other values, which are described herein again.

According to the method in the second method, the context model number ctxInc corresponding to the syntax element of the current coding unit can be determined.

At this time, according to the context model number ctxInc, the bit corresponding to the syntax element of the current coding unit may be decoded to obtain the value of the syntax element (e.g., pred _ mode _ ibc _ flag). For example, bits can be decoded according to the normal mode in CABAC, and reference may be made to the prior art specifically, which is not described herein again.

Alternatively, according to the value of the syntax element, the prediction mode of the current coding unit may be determined and the prediction mode information of the current coding unit may be saved.

The following description will be given by taking pred _ mode _ ibc _ flag as an example.

For example, if the pred _ MODE _ IBC _ flag value is 1, the prediction MODE of the current coding unit is MODE _ IBC, and accordingly, the CuPredMode [ chType ] [ x ] [ y ] value of any position covered by the current coding unit can be set to MODE _ IBC to save the prediction MODE of the current coding unit, where chType is the same as the first determination method, x0 ≦ x < x0+ cbWidth, and y0 ≦ y < y0+ cbHeight.

If the pred _ MODE _ ibc _ flag value is 0, the prediction MODE of the current coding unit may be determined by another syntax element pred _ MODE _ flag, and if the pred _ MODE _ flag is 0, the prediction MODE of the current coding unit is MODE _ INTER, and accordingly, the CuPredMode [ chType ] [ x ] [ y ] value of any position covered by the current coding unit may be set to be MODE _ INTER to save the prediction MODE of the current coding unit; otherwise, the prediction MODE of the current coding unit is MODE _ INTRA, and accordingly, the CuPredMode [ chType ] [ x ] [ y ] value of any position covered by the current coding unit can be set to MODE _ INTRA.

And S830, predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

Optionally, after obtaining the prediction mode of the current coding unit, the current coding unit is subjected to prediction information analysis, residual information analysis, prediction, inverse quantization, inverse transformation, reconstruction, and the like, so as to obtain a reconstructed pixel of the current coding unit.

How to implement these processes is not limited in the embodiment of the present application, for example, prediction information analysis, residual information analysis, intra prediction, inter prediction, intra block copy prediction, inverse quantization, inverse transformation, reconstruction, and the like in HEVC or VVC may be used to obtain a reconstructed pixel of a current coding unit, which may specifically refer to the prior art and is not described herein again.

The coding tree node partitioning method according to the embodiment of the present application is described in detail below with reference to the specific drawings.

Fig. 9 is a schematic flowchart of a coding tree node partitioning method according to an embodiment of the present application. The code tree node division method shown in fig. 9 may be performed by a code tree node division apparatus (which may be located in an image decoding apparatus (system) or an image encoding apparatus (system)), and specifically, the method shown in fig. 9 may be performed by the image encoding apparatus or the image decoding apparatus. The method shown in fig. 9 can be performed either at the encoding side or the decoding side, and the method 900 shown in fig. 9 includes

steps

910, 920 and 930, which are described in detail below.

S910, determining the type of the current coding tree node.

And the type of the current coding tree node is a brightness and chroma coding tree node, a brightness coding tree node or a chroma coding tree node. A luma-chroma coding tree node refers to a coding tree node including luma blocks and chroma blocks, a luma coding tree node refers to a coding tree node including luma blocks, and a chroma coding tree node refers to a coding tree node including chroma blocks.

S920, determining the division mode of the current coding tree node according to the type of the current coding tree node and/or the coding information of the adjacent image block.

The image blocks in the current coding tree node and the adjacent image blocks are spatially adjacent image blocks, the coding information includes Quad-tree depths (Quad-tree depths) of the adjacent image blocks and/or widths and heights of the adjacent image blocks, and the adjacent image blocks include adjacent luminance blocks and/or adjacent chrominance blocks.

Optionally, the determining a partition manner of the current coding tree node according to the type of the current coding tree node and/or the coding information of the adjacent image block may include: determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks; and determining the partition mode of the current coding tree node according to the context model number.

Similar to the embodiment in the method 800 in fig. 8, the context model number may be represented by ctxInc, and is determined by the above formula (1) and formula (2), which may specifically refer to the description in the method 800, and is not repeated here.

In the present application, the method for determining the context model number according to the difference of syntax elements of the current coding unit may specifically include the following two methods.

The method comprises the following steps:

alternatively, the syntax element of the current coding unit may be used to identify whether the current coding tree node uses quadtree partitioning, for example, the syntax element may be split _ qt _ flag.

Determining the context model number according to the quadtree depth of the adjacent luminance block and the quadtree depth of the current coding tree node when the current coding tree node is a luminance chrominance coding tree node or a luminance coding tree node;

in a case where the current coding tree node is a chroma coding tree node, a context model number of a syntax element of the current coding tree node may be determined according to a quadtree depth of the current coding tree node.

For example, in the case where the current coding unit is a luminance chrominance coding unit or a luminance coding unit, condL and condA may be determined by the above equation (1) or equation (2).

The value of codl is a decision result of cqtDepth [ xNbL ] [ yNbL ] > cqtDepth, the value of codA is a decision result of cqtDepth [ xNbA ] [ yNbA ] > cqtDepth, cqtDepth [ xNbL ] [ yNbL ] represents a quadtree depth of an image block (xNbL, yNbL) adjacent on the left side, cqtDepth [ xNbA ] [ yNbA ] represents a quadtree depth of an image block (xNbA, yNbA) adjacent on the upper side, and cqtDepth represents a quadtree depth of a current coding tree node.

The descriptions of the other variables (or parameters) in formula (1) and formula (2) are similar to the method in S820, and are not repeated here.

For example, both condL and condA may be set to 0.

At this time, the context model number ctxInc may be determined in one of the following two ways:

the first method is as follows:

condL and condA are set to 0 in advance, and ctxSetIdx is also set to 0, and at this time, as can be seen from the above equation (2), the context model number ctxInc corresponding to the syntax element of the current coding unit is also 0.

The second method comprises the following steps:

condL and condA are preset to 0, ctxSetIdx is (cqtDepth < 2)? 0:1, wherein the cqtDepth represents the quadtree depth of the current coding tree node, and according to the formula (2), if the quadtree depth of the current coding tree node is less than 2, ctxInc is 0; otherwise, ctxInc is 3.

It can be seen that, when the type of the current coding tree node is the chroma coding tree node, the context model number ctxInc may be determined according to the quadtree depth of the current coding tree node, that is, the determination of the context model number ctxInc may not depend on the coding information of the adjacent image block.

At this time, according to the context model number ctxInc, the bit corresponding to the syntax element of the current coding unit may be decoded to obtain the value of the syntax element (split _ qt _ flag). Reference may be made in particular to the prior art, which is not described in detail here.

Alternatively, the split _ qt _ flag may indicate whether the current coding tree node uses the quadtree partitioning, for example, a split _ qt _ flag of 1 indicates that the current node uses the quadtree partitioning manner to partition into four child nodes, and a split _ qt _ flag of 0 indicates that the current node does not use the quadtree partitioning manner.

Optionally, according to the value of the syntax element (split _ qt _ flag), the partition mode of the current coding tree node may be determined, a plurality of coding units subordinate to the current coding tree node may be obtained, and the quadtree depth of the current coding unit may be saved.

For example, if the type of the current coding unit is luma chroma coding unit or luma coding unit, the quadtree depth of the current coding unit may be saved to a variable cqtDepth [ x ] [ y ], where cqtDepth [ x ] [ y ] represents the quadtree depth with a coordinate position of (x, y), x0 ≦ x < x0+ cbWidth, y0 ≦ y < y0+ cbHeight, cbWidth is the width of the current coding unit, and cbHeight is the height of the current coding unit.

The above-described determination of the partition manner of the current coding tree node according to the value of the syntax element (split _ qt _ flag) is the prior art. For example, if split _ qt _ flag is 1, the current coding tree node is divided into four sub-nodes by using a quadtree division manner, and the quadtree depth of the sub-nodes is equal to the quadtree depth of the current coding tree node plus 1; and if the split _ qt _ flag is 0, the partition mode of the current coding tree node is one of binary tree partition or ternary tree partition, and further analyzing the code stream to determine the partition mode of the node, wherein the binary tree partition mode comprises horizontal bisection and vertical bisection, and the ternary tree partition mode comprises horizontal trisection and vertical trisection. The children of the current coding tree node may continue to be partitioned or not partitioned. When the coding tree node is not divided, the coding tree node corresponds to a coding unit, and the quadtree depth of the coding unit is equal to the quadtree depth of the coding tree node.

The second method comprises the following steps:

alternatively, the syntax element of the current coding unit may be used to identify whether the current coding tree node is partitioned, for example, the syntax element may be split _ cu _ flag.

Determining the context model number according to the width and height of the adjacent luminance block and the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a luminance chrominance coding tree node or a luminance coding tree node;

and determining the context model number of the syntax element of the current coding tree node according to the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a chroma coding unit.

Wherein, the value of condL is CbHeight [ chType ] [ xNbL ] [ yNbL ] < cbHeight's decision result, the value of condA is CbWidth [ chType ] [ xNbA ] [ yNbA ] < cbWidth's decision result, CbHeight [0] [ x ] [ y ] represents the height of the left side adjacent luminance block (xNbL, yNbL), CbWidth [0] [ x ] [ y ] represents the width of the left side adjacent luminance block (xNbL, yNbL), cbHeight represents the height of the current coding tree node, and cbWidth represents the width of the current coding tree node.

At this time, the context model number ctxInc may be determined in one of the following ways:

the first method is as follows:

condL is set to 0 in advance, condA is set to 0 in advance, and ctxSetIdx is also set to 0, and at this time, as can be seen from the above equation (2), the context model number ctxInc corresponding to the syntax element of the current coding unit is also 0.

The second method comprises the following steps:

condL is preset to 0, condA is preset to 1, and ctxSetIdx is set to 0, and at this time, as can be seen from the above equation (2), the context model number ctxInc corresponding to the syntax element of the current coding unit is 1.

The third method comprises the following steps:

condL is preset to 0 and condA is preset to 0, and in this case, ctxInc is equal to 3 × ctxSetIdx according to the above formula (1), and the ctxSetIdx determination method may refer to the prior art.

Alternatively, the ctxSetIdx (corresponding to the split _ cu _ flag) may be determined according to the availability of the current coding tree node partitioning manner in the VTM 5. For example, when ctxSetIdx takes values of 0, 1, and 2, the context model numbers ctxInc are equal to 0, 3, and 6, respectively.

The method is as follows:

condA is set to 0 in advance, andl can be determined by the height of the left-side neighboring chroma block and the height of the chroma block of the current coding unit, and at this time, the context model number ctxInc can be obtained by the above formula (1), wherein the ctxSetIdx determination method can refer to the prior art.

Alternatively, the ctxSetIdx (corresponding to split _ cu _ flag) method may be determined according to the availability of the current coding tree node partition mode in the VTM 5.

As can be seen from the above first to fourth manners, when the type of the current coding tree node is a chroma coding tree node, the context model number ctxInc may be determined according to the availability of the current coding tree node dividing manner, that is, the determination of the context model number ctxInc may not depend on the coding information of the upper adjacent image block.

At this time, according to the context model number ctxInc, the bit corresponding to the syntax element of the current coding unit may be decoded to obtain the value of the syntax element (split _ cu _ flag). Reference may be made in particular to the prior art, which is not described in detail here.

Alternatively, split _ cu _ flag may indicate whether the current coding tree node is partitioned. For example, a split _ cu _ flag of 1 indicates that the current node is divided into sub-nodes, and a split _ cu _ flag of 0 indicates that the current node is not divided.

Optionally, according to the value of the syntax element (split _ cu _ flag), the partition manner of the current coding tree node may be determined, and one or more coding units subordinate to the current coding tree node may be obtained.

For example, if the type of the coding unit (one of the one or more coding units) is a luma chroma coding unit or a luma coding unit, the width of the luma block of the coding unit may be saved to a variable CbWidth [0] [ x ] [ y ], the height of the luma block of the coding unit may be saved to a variable CbHeight [0] [ x ] [ y ], where x0 ≦ x < x0+ cbWidth1, y0 ≦ y < y0+ cbHeight1, cbWidth1 is the width of the coding unit, and cbHeight1 is the height of the coding unit; if the coding unit type is chroma coding unit, the width of the chroma block of the coding unit can be stored to the variable CbWidth [1] [ x ] [ y ], the height of the chroma block of the coding unit can be stored to the variable CbHeight [1] [ x ] [ y ], wherein x0 is not less than x < x0+ cbWidth1, y0 is not less than y < y0+ cbHeight1, cbWidth1 is the width of the coding unit, and cbHeight1 is the height of the coding unit.

It should be noted that when a coding tree node is not divided, it corresponds to a coding unit. At this time, the width and height of the coding unit are higher than those of the coding tree node to which the coding unit belongs, i.e., at this time cbWidth1 is equal to cbWidth and cbHeight1 is equal to cbHeight.

The method for determining the partition mode of the current coding tree node according to the value of the flag bit split _ cu _ flag is the prior art. For example, if the flag split _ cu _ flag is 1, dividing the current coding tree node into child nodes; and if the split _ cu _ flag is 0, the current coding tree node is not divided, wherein the division modes of the coding tree node into the sub-nodes comprise four, horizontal two, vertical two, horizontal three and vertical three. When the coding tree node continues to be divided, the specific division manner may be determined by other syntax elements, such as split _ qt _ flag, etc.

And S930, dividing the current coding tree node according to the division mode of the coding tree node.

How to implement the S930 processing in this embodiment is not limited, for example, a coding tree node division method in the VVC may be used, and details are not described here. Leaf nodes on the coding tree can be finally determined according to the coding tree division, each leaf node corresponds to one coding unit, and the decoding coding unit can obtain a reconstructed image of the coding unit.

The image prediction method and the coding tree node division method according to the embodiment of the present application are described in detail with reference to fig. 8 and 9, and the image prediction apparatus and the coding tree node division apparatus according to the embodiment of the present application are described with reference to fig. 10 and 11. It should be understood that the image prediction apparatus shown in fig. 10 is capable of performing the various steps in the image prediction method 800 in fig. 8.

The image prediction apparatus 1000 shown in fig. 10 includes: a determination module 1010, a processing module 1020, and a prediction module 1030.

A determining module 1010, configured to determine a type of a current coding unit, where the type of the current coding unit is a luma chroma coding unit, a luma coding unit, or a chroma coding unit;

a processing module 1020, configured to determine a prediction mode of a current coding unit according to a type of the current coding unit and/or a prediction mode of an adjacent image block, where an image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block includes an adjacent luminance block and/or an adjacent chrominance block;

a prediction module 1030, configured to predict an image block in the current coding unit according to a prediction mode of the current coding unit.

Optionally, the processing module 1020 is specifically configured to: determining a context model number corresponding to a syntax element of the current coding unit according to the type of the current coding unit and/or a prediction mode of an adjacent image block; and determining the prediction mode of the current coding unit according to the context model number.

Optionally, the processing module 1020 is specifically configured to: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or determining condL according to the prediction mode of the left side adjacent chroma block and determining condA according to the prediction mode of the upper side adjacent chroma block when the current coding unit is the chroma coding unit; determining the context model number according to the condL and the condA; wherein the condL and the condA are binary variables.

Optionally, the processing module 1020 is specifically configured to: determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or determining the context model number according to preset condL and condA under the condition that the current coding unit is a chroma coding unit; wherein the condL and the condA are binary variables.

Optionally, the syntax element is pred _ mode _ ibc _ flag, the syntax element is used to identify whether the current coding unit uses intra block copy prediction, the condL is used to indicate whether the prediction mode of the left neighboring image block is intra block copy prediction, and the condA is used to indicate whether the prediction mode of the upper neighboring image block is intra block copy prediction.

It should be understood that the code tree node partitioning apparatus shown in FIG. 11 is capable of performing the various steps in the code tree node partitioning method 900 of FIG. 9.

Fig. 11 is a schematic block diagram of a coding tree node division apparatus according to an embodiment of the present application.

The coding tree node division apparatus 1100 shown in fig. 11 includes: a determination module 1110, a processing module 1120, and a partitioning module 1130.

A determining module 1110, configured to determine a type of a current coding tree node, where the type of the current coding tree node is a luma-chroma coding tree node, or a chroma coding tree node;

the processing module 1120 is configured to determine a partition manner of a current coding tree node according to a type of the current coding tree node and/or coding information of an adjacent image block, where an image block in the current coding tree node and the adjacent image block are spatially adjacent image blocks, the coding information includes a quadtree depth of the adjacent image block and/or a width and a height of the adjacent image block, and the adjacent image block includes an adjacent luminance block and/or an adjacent chrominance block;

a dividing module 1130, configured to divide the current coding tree node according to the dividing manner of the coding tree node.

Optionally, the processing module 1120 is specifically configured to: determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks; and determining the partition mode of the current coding tree node according to the context model number.

Optionally, the processing module 1120 is specifically configured to: determining the context model number according to the quadtree depth of the adjacent brightness blocks and the quadtree depth of the current coding tree node under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or determining the context model number of the syntax element of the current coding tree node according to the quadtree depth of the current coding tree node under the condition that the current coding tree node is the chroma coding tree node.

Optionally, the syntax element is split _ qt _ flag for identifying whether the current coding tree node uses quadtree partitioning.

Optionally, the processing module 1120 is specifically configured to: determining the context model number according to the width and height of the adjacent brightness blocks and the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; and under the condition that the current coding tree node is a chroma coding unit, determining the context model number of the syntax element of the current coding tree node according to the availability of the current coding tree node dividing mode.

Optionally, the syntax element is split _ cu _ flag, which is used to identify whether the current coding tree node is divided.

Fig. 12 is a schematic block diagram of an image prediction apparatus according to an embodiment of the present application.

The image prediction apparatus 1200 shown in fig. 12 includes: a processing module 1210 and a prediction module 1220.

A processing module 1210, configured to determine, when a current coding unit is a chroma coding unit, a context model number corresponding to a syntax element of the current coding unit according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; the condL indicates whether a prediction mode of the left-side neighboring chroma block is intra block copy prediction, and the condA indicates whether a prediction mode of the upper-side neighboring chroma block is intra block copy prediction; or, the condL and the condA are both preset values;

the processing module 1210 is configured to determine a prediction mode of the current coding unit according to the context model number;

the prediction module 1220 is configured to predict an image block in the current coding unit according to the prediction mode of the current coding unit.

Fig. 13 is a schematic block diagram of a coding tree node division apparatus according to an embodiment of the present application.

The coding tree node division apparatus 1300 shown in fig. 13 includes: a processing module 1310 and a partitioning module 1320.

A processing module 1310, configured to determine, when the current coding tree node is a chroma coding tree node, a context model number corresponding to a syntax element of the current coding tree node according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available; both the condL and the condA are preset values; or, the condL is determined by the current coding tree node, and the condA is a preset value;

the processing module 1310 is configured to determine a partitioning manner of the current coding tree node according to the context model number;

a partitioning module 1320, configured to partition the current coding tree node according to the partitioning manner of the coding tree node.

Fig. 14 is a schematic hardware configuration diagram of an image encoding/decoding apparatus according to an embodiment of the present application. The apparatus 1400 shown in fig. 14 (which apparatus 1400 may be specifically a computer device) includes a memory 1410, a processor 1420, a communication interface 1430, and a bus 1440. Wherein, the memory 1410, the processor 1420, and the communication interface 1430 are communicatively coupled to each other via a bus 1440.

The memory 1410 may be a Read Only Memory (ROM), a static memory device, a dynamic memory device, or a Random Access Memory (RAM). The memory 1410 may store a program, and the processor 1420 is configured to perform the steps of the image prediction method of the embodiment of the present application when the program stored in the memory 1410 is executed by the processor 1420.

The processor 1420 may be a general-purpose Central Processing Unit (CPU), a microprocessor, an Application Specific Integrated Circuit (ASIC), a Graphics Processing Unit (GPU), or one or more integrated circuits, and is configured to execute related programs to implement the image prediction method according to the embodiment of the present invention.

Processor 1420 may also be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the image prediction method of the present application may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 1420.

The processor 1420 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 1420, and the processor 1420 reads information in the memory 1420, in conjunction with hardware thereof, to complete functions required to be performed by units included in the image prediction apparatus, or to perform the image prediction method of the present embodiment of the method.

Communication interface 1430 enables communication between apparatus 1400 and other devices or communication networks using transceiver devices such as, but not limited to, transceivers. For example, information of the neural network to be constructed and training data required in constructing the neural network may be acquired through the communication interface 1430.

Bus 1440 may include a pathway to transfer information between various components of device 1400 (e.g., memory 1410, processor 1420, communication interface 1430).

The determination module 1010, the processing module 1020, and the prediction module 1030 in the apparatus 1000 in fig. 10 described above correspond to the processor 1420 in the image encoding/decoding apparatus 1400.

Alternatively, the determination module 1110, the processing module 1120, and the division module 1130 in the apparatus 1100 in fig. 11 described above correspond to the processor 1420 in the image encoding/decoding apparatus 1400.

Alternatively, processing module 1210 and prediction module 1220 in apparatus 1200 in fig. 12 described above correspond to processor 1420 in image encoding/decoding apparatus 1400.

Alternatively, the processing module 1310 and the dividing module 1320 in the apparatus 1300 in fig. 13 correspond to the processor 1420 in the image encoding/decoding apparatus 1400.

In addition, when the image encoding/decoding apparatus 1400 encodes a video image, the video image may be acquired through a communication interface, and then the acquired video image is encoded to obtain encoded video data, and the encoded video data may be transmitted to a video decoding device through the communication interface 1430.

When the image encoding/decoding apparatus 1400 decodes a video image, the video image may be acquired through the communication interface 1430, and then the acquired video image is decoded to obtain a video image to be displayed.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An image prediction method, comprising:

determining the type of a current coding unit, wherein the type of the current coding unit is a brightness and chrominance coding unit, a brightness coding unit or a chrominance coding unit;

determining a prediction mode of a current coding unit according to the type of the current coding unit and/or the prediction mode of an adjacent image block, wherein the image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block comprises an adjacent luminance block and/or an adjacent chrominance block;

and predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

2. The method according to claim 1, wherein determining the prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of the neighboring image block comprises:

determining a context model number corresponding to a syntax element of the current coding unit according to the type of the current coding unit and/or a prediction mode of an adjacent image block;

and determining the prediction mode of the current coding unit according to the context model number.

3. The method according to claim 2, wherein the determining the context model number corresponding to the syntax element of the current coding unit according to the type of the current coding unit and/or the prediction mode of the neighboring image block comprises:

determining condL according to a prediction mode of a left-side adjacent luminance block and determining condA according to a prediction mode of an upper-side adjacent luminance block in the case that the current coding unit is a luminance chrominance coding unit or a luminance coding unit; determining the context model number according to the condL and the condA; or

Determining condL according to a prediction mode of a left-side adjacent chroma block and determining condA according to a prediction mode of an upper-side adjacent chroma block in the case that the current coding unit is a chroma coding unit; determining the context model number according to the condL and the condA;

wherein the condL and the condA are binary variables.

4. The method of claim 3, wherein the determining the context model number comprises determining the context model number according to the following equation:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is the context model number, ctxSetIdx is the number of the context group;

when the current coding unit is a luma chroma coding unit or a luma coding unit, the condL indicates whether a prediction mode of the left neighboring luma block is intra block copy prediction, the condA indicates whether a prediction mode of the upper neighboring luma block is intra block copy prediction, the availableL indicates whether the left neighboring luma block is available, and the availableA indicates whether the upper neighboring luma block is available; or

When the current coding unit is a chroma coding unit, the condL indicates whether the prediction mode of the left-side neighboring chroma block is intra block copy prediction, the condA indicates whether the prediction mode of the upper-side neighboring chroma block is intra block copy prediction, the availableL indicates whether the left-side neighboring chroma block is available, and the availableA indicates whether the upper-side neighboring chroma block is available.

5. The method according to claim 2, wherein the determining the context model number corresponding to the syntax element of the current coding unit according to the type of the current coding unit and/or the prediction mode of the neighboring image block comprises:

Determining the context model number according to a preset condL and a preset condA under the condition that the current coding unit is a chroma coding unit;

wherein the condL and the condA are binary variables.

6. The method of claim 5, wherein the determining the context model number comprises determining the context model number according to the following equation:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

When the current coding unit is a chroma coding unit, the condL is a preset value, the condA is a preset value, the availableL indicates whether the left-side neighboring chroma block is available, and the availableA indicates whether the upper-side neighboring chroma block is available.

7. The method of any of claims 2 to 6, wherein the syntax element is pred _ mode _ ibc _ flag, the syntax element is used to identify whether the current coding unit uses intra block copy prediction, the condL is used to indicate whether the prediction mode of the left neighboring image block is intra block copy prediction, and the condA is used to indicate whether the prediction mode of the upper neighboring image block is intra block copy prediction.

8. A method for partitioning nodes of a coding tree, comprising:

determining the type of a current coding tree node, wherein the type of the current coding tree node is a brightness and chrominance coding tree node, a brightness coding tree node or a chrominance coding tree node;

determining a division mode of a current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks, wherein the image blocks in the current coding tree node and the adjacent image blocks are spatially adjacent image blocks, the coding information comprises the quadtree depth of the adjacent image blocks and/or the width and height of the adjacent image blocks, and the adjacent image blocks comprise adjacent luminance blocks and/or adjacent chrominance blocks;

and dividing the current coding tree node according to the division mode of the coding tree node.

9. The method according to claim 8, wherein the determining a partition type of the current coding tree node according to the type of the current coding tree node and/or the coding information of the neighboring image blocks comprises:

determining a context model number corresponding to a syntax element of the current coding tree node according to the type of the current coding tree node and/or coding information of adjacent image blocks;

and determining the partition mode of the current coding tree node according to the context model number.

10. The method according to claim 9, wherein determining the context model number corresponding to the syntax element of the current coding tree node according to the type of the current coding tree node and/or the coding information of the neighboring image block comprises:

determining the context model number according to the quadtree depth of the adjacent brightness blocks and the quadtree depth of the current coding tree node under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or

And under the condition that the current coding tree node is a chroma coding tree node, determining the context model number according to the quadtree depth of the current coding tree node.

11. The method of claim 10, wherein determining the context model number comprises determining the context model number according to the following equation:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

when the current coding tree node is a luma chroma coding tree node or a luma coding tree node, the condL indicates whether a quadtree depth of the left neighboring luma block is greater than a quadtree depth of the current coding tree node, the condA indicates whether a quadtree depth of the upper neighboring luma block is greater than a quadtree depth of the current coding tree node, the availableL indicates whether the left neighboring luma block is available, and the availableA indicates whether the upper neighboring luma block is available; or

12. The method of claim 10 or 11, wherein the syntax element is split qtlag, which is used to identify whether the current coding tree node uses quadtree partitioning.

13. The method according to claim 9, wherein determining the context model number corresponding to the syntax element of the current coding tree node according to the type of the current coding tree node and/or the coding information of the neighboring image block comprises:

determining the context model number according to the width and height of the adjacent brightness blocks and the availability of the current coding tree node dividing mode under the condition that the current coding tree node is a brightness and chrominance coding tree node or a brightness coding tree node; or

And under the condition that the current coding tree node is a chroma coding unit, determining the context model number according to the availability of the current coding tree node division mode.

14. The method of claim 13, wherein determining the context model number comprises determining the context model number according to the following equation:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

in a case where the current coding tree node is a luma chroma coding tree node or a luma coding tree node, condL indicates whether the width and height of the left-side neighboring luma block are greater than those of the current coding tree node, condA indicates whether the width and height of the upper-side neighboring luma block are greater than those of the current coding tree node, availableL indicates whether the left-side neighboring luma block is available, and availableA indicates whether the upper-side neighboring luma block is available; or

In a case where the current coding unit is a chroma coding unit, condL is a prediction value or is determined by the current coding tree node, condA is a preset value, availableL indicates whether the left-side neighboring chroma block is available, and availableA indicates whether the upper-side neighboring chroma block is available.

15. The method of claim 13 or 14, wherein the syntax element is a split cu flag for identifying whether the current coding tree node is partitioned.

16. An image prediction method, comprising:

determining a context model number corresponding to a syntax element of a current coding unit according to the following formula when the current coding unit is a chroma coding unit:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

wherein ctxInc is a context model number, ctxSetIdx is a number of a context group, availableL indicates whether the left side neighboring chroma block is available, and availableA indicates whether the upper side neighboring chroma block is available;

the condL indicates whether a prediction mode of the left-side neighboring chroma block is intra block copy prediction, and the condA indicates whether a prediction mode of the upper-side neighboring chroma block is intra block copy prediction; or, the condL and the condA are both preset values;

determining a prediction mode of the current coding unit according to the context model number;

17. A method for partitioning nodes of a coding tree, comprising:

determining a context model number corresponding to a syntax element of a current coding tree node according to the following formula under the condition that the current coding tree node is a chroma coding tree node:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

both the condL and the condA are preset values; or, the condL is determined by the current coding tree node, and the condA is a preset value;

determining the partition mode of the current coding tree node according to the context model number;

18. An image prediction apparatus comprising:

the device comprises a determining module, a judging module and a judging module, wherein the determining module is used for determining the type of a current coding unit, and the type of the current coding unit is a brightness and chrominance coding unit, a brightness coding unit or a chrominance coding unit;

the processing module is used for determining the prediction mode of the current coding unit according to the type of the current coding unit and/or the prediction mode of an adjacent image block, wherein the image block in the current coding unit and the adjacent image block are spatially adjacent image blocks, and the adjacent image block comprises an adjacent luminance block and/or an adjacent chrominance block;

and the prediction module is used for predicting the image block in the current coding unit according to the prediction mode of the current coding unit.

19. The apparatus of claim 18, wherein the processing module is specifically configured to:

20. The apparatus of claim 19, wherein the processing module is specifically configured to:

wherein the condL and the condA are binary variables.

21. The apparatus of claim 20, wherein the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

22. The apparatus of claim 19, wherein the processing module is specifically configured to:

wherein the condL and the condA are binary variables.

23. The apparatus of claim 22, wherein the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

24. The apparatus of any of claims 19 to 23, wherein the syntax element is pred _ mode _ ibc _ flag, the syntax element is used to identify whether the current coding unit uses intra block copy prediction, the condL is used to indicate whether a prediction mode of a left neighboring image block is intra block copy prediction, and the condA is used to indicate whether a prediction mode of an upper neighboring image block is intra block copy prediction.

25. An apparatus for partitioning nodes of a coding tree, comprising:

the determining module is used for determining the type of a current coding tree node, wherein the type of the current coding tree node is a brightness and chrominance coding tree node, a brightness coding tree node or a chrominance coding tree node;

the processing module is used for determining the division mode of the current coding tree node according to the type of the current coding tree node and/or the coding information of the adjacent image blocks, wherein the image blocks in the current coding tree node and the adjacent image blocks are spatially adjacent image blocks, the coding information comprises the quadtree depth of the adjacent image blocks and/or the width and height of the adjacent image blocks, and the adjacent image blocks comprise adjacent luminance blocks and/or adjacent chrominance blocks;

and the dividing module is used for dividing the current coding tree node according to the dividing mode of the coding tree node.

26. The apparatus of claim 25, wherein the processing module is specifically configured to:

27. The apparatus of claim 26, wherein the processing module is specifically configured to:

28. The apparatus of claim 27, wherein the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

29. The apparatus of claim 27 or 28, wherein the syntax element is split qtlag, identifying whether the current coding tree node uses quadtree partitioning.

30. The apparatus of claim 26, wherein the processing module is specifically configured to:

31. The apparatus of claim 30, wherein the processing module is specifically configured to determine the context model number according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

32. The apparatus of claim 30 or 31, wherein the syntax element is a split cu flag for identifying whether the current coding tree node is partitioned.

33. An image prediction apparatus comprising:

a processing module, configured to determine, when a current coding unit is a chroma coding unit, a context model number corresponding to a syntax element of the current coding unit according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

the processing module is configured to determine a prediction mode of the current coding unit according to the context model number;

34. An apparatus for partitioning nodes of a coding tree, comprising:

a processing module, configured to determine, when a current coding tree node is a chroma coding tree node, a context model number corresponding to a syntax element of the current coding tree node according to the following formula:

ctxInc＝(condL&&availableL)+(condA&&availableA)+ctxSetIdx*3

the processing module is used for determining the partition mode of the current coding tree node according to the context model number;

35. A video encoding and decoding apparatus, comprising:

a memory for storing a program;

a processor for executing the memory-stored program, the processor performing the method of any of claims 1-7 or any of claims 8-15 or 16 or 17 when the memory-stored program is executed by the processor.

36. A video encoder, characterized in that the video encoder comprises an apparatus according to any of claims 18-24 or 25-32 or 33 or 34 or 35.

37. A video decoder, characterized in that it comprises an apparatus according to any of claims 18-24 or 25-32 or 33 or 34 or 35.

38. A video codec device, characterized in that the video codec device comprises a video encoder according to claim 36 and/or a video decoder according to claim 37.

39. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program executable by a processor, which processor executes the method according to any of claims 1-7 or any of claims 8-15 or 16 or 17 when the computer program is executed by the processor.