RU2801327C2 - Intra prediction method and device for a video sequence - Google Patents

Abstract

FIELD: video coding and decoding technologies.

SUBSTANCE: invention relates to an intra prediction method. An intra prediction method for a video sequence is proposed. The method includes: obtaining a size and splitting mode of a chroma coding tree node; determining, based on the size and splitting mode of the chrominance coding tree node, as to whether to allow performing cross-component linear model (CCLM) intra prediction on a chroma coding unit included in the chrominance coding tree node; determining a chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit; and processing a chroma coding unit based on the chroma coding unit prediction mode to obtain chroma coding unit prediction samples.

EFFECT: reducing the delay in processing a chroma coding unit and increasing the throughput of a hardware decoder.

18 cl, 11 dwg, 2 tbl

Description

Cross-reference to related application

This application claims the priority of Chinese Patent Application No. 201910370987.9 filed with the National Intellectual Property Office of China on April 30, 2019 and entitled "INTRA PREDICTION METHOD AND APPARATUS FOR VIDEO SEQUENCE", which is incorporated herein in its entirety by reference.

The technical field to which the invention belongs

The present application relates to the field of video encoding and decoding technologies and, in particular, to an intra prediction method and apparatus for a video sequence.

State of the art

In the H.265 video coding standard, an image frame is divided into coding tree units (CTUs) that do not overlap with each other, and the CTU size can be set to 64×64 or another value. The 64×64 CTU is a rectangular sample matrix including 64×64 samples. The matrix sample matrix includes 64 columns, each column includes 64 samples, and each sample includes a luma component and/or a chrominance component.

H.265 is based on a quad-tree (QT) splitting mode in which the CTU is used as the root node of the quad tree and the CTU is recursively split into multiple leaf nodes. A node corresponds to one area of the image. If the node does not continue to split, the node is called a leaf node, and the image area corresponding to the node becomes CU. If the node continues to split, the image region corresponding to the node is divided into four image regions of equal size, and each region corresponds to one node. Whether a node is to be split is determined by the split flag, which is in the bitstream and corresponds to the node. The depth of the root node is 0, and the depth of the child node is the depth of the parent node plus 1.

A CTU node whose size is 64x64 (with depth 0) cannot be split based on the split flag corresponding to the CTU node and become a 64x64 CU, or can be split into four nodes whose size is 32x32 (with depth 1). Each of the four nodes, whose size is 32×32, may continue to split or no longer split based on the split flag corresponding to the node. If a 32x32 knot continues to split, four 16x16 knots (with a depth of 2) are generated. The rest can be deduced by analogy until no node is split. In this case, one CTU is divided into one CU group.

On the basis of quadtree splitting, a binary tree splitting mode (binary tree, BT) and a ternary tree splitting mode (ternary tree, TT) are added to the VTM reference software.

In addition, QT and BT/TT split cascading mode can be used in a versatile video coding test model (VTM) and is called quadtree plus multi-type tree (QT-BTT) mode. That is, a node in the level 1 coding tree can only be subdivided into child nodes using the QT mode, and the end node in the level 1 coding tree is the root node of the level 2 coding tree; a node in the layer 2 coding tree may be split into child nodes using one of the following four split modes: horizontal binary split, vertical binary split, horizontal ternary split, and vertical ternary split; the leaf node of the level 2 coding tree is the unit of coding.

After it is known through parsing that the node is a leaf node and the leaf node is a CU, encoding information (including information such as prediction mode and conversion factor of the CU, such as the syntax structure coding_unit() in H .265) corresponding to CU. Then, decoding processing such as prediction, dequantization, inverse transform, and loop filtering are performed on the CU based on the encoding information to generate a reconstructed image corresponding to the CU. A flexible partitioning tree structure such as QT-MTT allows CTUs to be partitioned into appropriately sized CUs based on the local feature of the image.

The mode of splitting a CTU into a CU group corresponds to one coding tree. In VTM, the split tree structure allows the use of an internal image (image I). In this case, starting from a specific node A in the coding tree, the luminance block of node A is divided using the luminance coding tree, and the leaf node of the luminance coding tree is the CU of luma and only includes luma samples. The chroma block of node A is partitioned using a chroma coding tree, and a leaf node of the chroma coding tree is a chroma CU and only includes chroma samples.

In VTM5 (namely, VTM software version 5), the split tree structure can be used for the internal image. For an intra picture using a split tree structure, a 128x128 coding tree node can be split into four 64x64 nodes using a quadtree split mode, and each 64x64 node includes luma samples and chrominance samples. The splitting tree structure is used for a 64x64 node, that is, a 64x64 node luma block is split using a luma coding tree, and a 64x64 node chrominance block is split using a chroma coding tree. The split mode used for the luminance coding tree may be different from the split mode used for the chrominance coding tree. For example, a 64×64 node luminance block may be partitioned using a quadtree partitioning mode, and a chrominance block can be partitioned using a horizontal binary partitioning mode. In the YUV4:2:0 format, since the horizontal and vertical chroma sampling rates are half that of the chroma, an M×N node corresponds to (M/2)×(N/2) chrominance samples.

However, when a split tree structure is used for an intra picture, a relatively large delay may occur in chrominance signal processing, which reduces the throughput of a hardware decoder.

The essence of the invention

Embodiments of the present application provide an intra prediction method and apparatus for a video sequence. Embodiments of the present application can reduce the delay in chroma processing and increase the throughput of a hardware decoder. A video sequence includes one or more pictures.

For brevity, the size and shape of a node in the embodiments of the present invention are the size and shape of the image area corresponding to the node. In embodiments of the present invention, both the width and height of a node are represented by the number of luminance samples corresponding to the node.

According to a first aspect, an embodiment of the present invention provides an intra prediction method for a video sequence, including:

obtaining a size and splitting mode of a chroma coding tree node; determining, based on the size and partitioning mode of the chrominance coding tree node, as to whether to allow performing inter-component linear model (CCLM) intra prediction on a chroma coding unit included in the chroma coding tree node; determining a chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit; and processing a chroma coding unit based on the chroma coding unit prediction mode to obtain chroma coding unit prediction samples. Whether to allow CCLM to be performed on a chroma coding unit included in a chroma coding tree node is determined based on the size and partitioning mode of the chroma coding tree node, thereby reducing the latency in processing the chroma coding unit on which CCLM is performed and improving hardware throughput. decoder.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node includes :

when M and N are equal to a predetermined threshold T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node includes :

when M is T1 and N is T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an exemplary embodiment, determining, based on the size and split mode of a chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in a chroma coding tree node includes:

determining, based on the size and splitting mode of the chroma coding tree node, the splitting mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the inner subsection for the corresponding luma block when the luma coding tree node is not split, and whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node.

In an exemplary embodiment, the size of a chrominance coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node and the split mode of the luma coding tree node corresponding to the chroma coding tree node, whether to allow CCLM to be performed on the chroma coding unit included into a chroma coding tree node, includes:

when the division mode of the chroma coding tree node satisfies the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or

when the split mode of the chroma coding tree node does not satisfy the third predetermined condition, M is T1, and N is equal to T1, if the split mode of the chroma coding tree node satisfies the first predetermined condition, determining whether to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of the chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the internal subsection for the corresponding luma block when the luma coding tree node is not split, and whether to allow CCLM execution on the chroma coding unit included in the chroma coding tree node includes:

when the division mode of the chroma coding tree node satisfies any one condition in the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the split mode of the chroma coding tree node does not satisfy the third predetermined condition, N=T1 and M=T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an exemplary embodiment, the third predetermined condition includes one or any combination of the following conditions 1-13, and conditions 1-13 are represented as follows:

Condition 1: The division mode of the luminance coding tree node corresponding to the chroma coding tree node is not division, and the ISP mode is used for the luma block of the luminance coding tree node, where the size of the luminance coding tree node is T1×T1.

Condition 2: The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes, where each of the size of the chroma coding tree node, the node size of the luminance coding tree and the size of the luma block is T1×T1.

Condition 3: The division mode of the luminance coding tree node corresponding to the chroma coding tree node is not a division, the horizontal ISP mode is used for the luminance block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes using one of the vertical binary division mode, a vertical ternary partitioning mode; or a quadtree partitioning mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luma block size is each T1×T1.

Condition 4: The division mode of the luminance coding tree node corresponding to the chrominance coding tree node is not partitioning, the horizontal ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes using one of the horizontal ternary division mode, a vertical binary splitting mode, a vertical ternary splitting mode, or a quadtree splitting mode, where each of a chroma coding tree node size, a luminance coding tree node size, and a luminance block size is T1×T1.

Condition 5: The division mode of the luminance coding tree node corresponding to the chroma coding tree node is not a division, the horizontal ISP mode is used for the luminance block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes using one of the vertical binary division mode, a vertical ternary division mode; or a horizontal ternary division mode, where the luma coding tree node size is T1×T1 and the chrominance coding tree node size is T1×(T1/2).

Condition 6: The splitting mode of the luma coding tree node corresponding to the chroma coding tree node is not split, the vertical ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the horizontal binary splitting mode, a horizontal ternary splitting mode; or a quadtree splitting mode, where both the chroma coding tree node size and the luminance coding tree node size are T1×T1.

Condition 7: The division mode of the luminance coding tree node corresponding to the chroma coding tree node is not a division, the ISP vertical prediction mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes using one of the vertical ternary division mode , a horizontal binary split mode, a horizontal ternary split mode, or a quadtree split mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1.

Condition 8: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the vertical ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the horizontal binary splitting mode, a horizontal ternary partitioning mode; or a vertical ternary partitioning mode, where the luma coding tree node size and the luma block size are T1×T1, and the chroma coding tree node size is T1×(T1/2).

Condition 9: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the horizontal binary partitioning mode, where the size of the luma coding tree node is T1×T1.

Condition 10: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the vertical binary splitting mode, where the luminance coding tree node size is T1×T1.

Condition 11: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the horizontal ternary partitioning mode, where the luminance coding tree node size is T1×T1.

Condition 12: The luma coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the vertical ternary splitting mode, where the luminance coding tree node size is T1×T1.

Condition 13: The split mode used for the luminance coding tree node corresponding to the chrominance coding tree node is a split mode other than split mode and quadtree split mode, where the luma coding tree node size is T1×T1.

It should be noted here that the fact that a chroma coding tree node is divided into child nodes specifically means that a chroma coding tree node is divided into child nodes using one of a horizontal binary splitting mode, a vertical binary splitting mode, a horizontal ternary splitting mode, vertical ternary splitting mode; and quadtree splitting mode.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the ISP prediction mode is used for the luminance block of the luminance coding tree node, where the luma coding tree node size and the luma block size are T1×T1.

Optionally, the third predetermined condition includes:

The splitting mode of the luma coding tree node corresponding to the chroma coding tree node is not split, the ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes, where each of the chrominance coding tree node size, the tree node size luminance coding and luminance block size is T1×T1.

Optionally, the third predetermined condition includes condition 1 and condition 13.

Optionally, the third predetermined condition includes condition 2 and condition 13.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes; or the luma coding tree node splitting mode is one of a horizontal binary splitting mode and a vertical binary splitting mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1.

Optionally, the third predetermined condition includes condition 3, condition 5, condition 6, condition 8, and condition 13.

Optionally, the third predetermined condition includes condition 4, condition 5, condition 7, condition 8, and condition 13.

In an exemplary embodiment, the third predetermined condition includes condition 3, condition 5, condition 7, condition 8, condition 9, condition 10, condition 11, and condition 12.

In an exemplary embodiment, the predetermined threshold T1 is 64.

According to a second aspect, an embodiment of the present invention provides an intra prediction method for a video sequence, including:

parsing the bitstream to obtain a first identifier and a second identifier, where the first identifier is used to indicate whether a split tree structure is used for an internal picture in the video sequence, and the second identifier is used to indicate whether to allow CCLM to be performed on a chrominance block in the video sequence; And

if the first identifier indicates that the split tree structure is used for an intra picture in the video sequence, and the second identifier indicates that CCLM can be performed on a chrominance unit in the video sequence, performing an intra prediction method for the described video sequence in any of the first aspect and embodiments of the first aspect.

According to a third aspect, an embodiment of the present invention provides an intra prediction apparatus for a video sequence, including:

an acquisition unit, configured to obtain a size and split mode of a chroma coding tree node;

a determining unit, configured to determine, based on the size and split mode of the chroma coding tree node, whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node; and determining a chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit; And

a predictor configured to process a chroma coding unit based on a chroma coding unit prediction mode to obtain chroma coding unit prediction samples.

In an exemplary embodiment, the size of a chroma coding tree node is MxN, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node, the block definitions are specially made with the ability to:

when M and N are equal to a predetermined threshold T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chrominance coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of a chroma coding tree node is MxN, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node, the block definitions are specially made with the ability to:

when M is T1 and N is T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an exemplary embodiment, in the aspect of determining, based on the size and splitting mode of a chroma coding tree node, as to whether to allow intra-component linear model (CCLM) prediction to be performed on a chroma coding unit included in a chroma coding tree node, a determination unit specifically made with the ability to:

determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode for the corresponding luma block when the luminance coding tree node is not split, regardless of whether whether CCLM is allowed to be performed on the chroma coding unit included in the chroma coding tree node.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the inner subsection for the corresponding luma block, when the luminance coding tree node is not divided, and whether to allow the execution of CCLM on the chroma coding unit included in the chroma coding tree node, the determining block is specifically configured to:

when the division mode of the chroma coding tree node satisfies the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the division mode of the chroma coding tree node does not satisfy the third predetermined condition, M is T1, and N is T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chrominance coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the inner subsection for the corresponding luma block, when the luminance coding tree node is not divided, and whether to allow the execution of CCLM on the chroma coding unit included in the chroma coding tree node, the determining block is specifically configured to:

when the division mode of the chroma coding tree node satisfies any one condition in the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the split mode of the chroma coding tree node does not satisfy the third predetermined condition, N=T1 and M=T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining to allow execution of CCLM on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

Optionally, the third predetermined condition includes one or more of: condition 1, condition 2, condition 3, condition 4, condition 5, condition 6, condition 7, condition 8, condition 9, condition 10, condition 11, condition 12, and conditions 13 in the first aspect.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the ISP prediction mode is used for the luminance block of the luminance coding tree node, where the luma coding tree node size and the luma block size are T1×T1.

Optionally, the third predetermined condition includes:

The splitting mode of the luma coding tree node corresponding to the chroma coding tree node is not split, the ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes, where each of the chrominance coding tree node size, the tree node size luminance coding and luminance block size is T1×T1.

In an exemplary embodiment, the third predetermined condition includes condition 1 and condition 13 in the first aspect.

In an exemplary embodiment, the third predetermined condition includes condition 2 and condition 13 in the first aspect.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes; or the luma coding tree node split mode is one of a horizontal binary split mode and a vertical binary split mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1.

In an exemplary embodiment, the third predetermined condition includes condition 3, condition 5, condition 6, condition 8, and condition 13 in the first aspect.

In an exemplary embodiment, the third predetermined condition includes condition 4, condition 5, condition 7, condition 8, and condition 13 in the first aspect.

In an exemplary embodiment, the third predetermined condition includes condition 3, condition 5, condition 7, condition 8, condition 9, condition 10, condition 11, and condition 12 in the first aspect.

In an exemplary embodiment, the predetermined threshold T1 is 64.

According to a fourth aspect, an embodiment of the present invention provides an intra prediction device for a video sequence, including:

a decoding block configured to parse the bitstream to obtain a first identifier and a second identifier, where the first identifier is used to indicate whether a split tree structure is used for an internal picture in the video sequence, and the second identifier is used to indicate whether to allow CCLM execution on the block chromaticity in the video sequence; And

a prediction block configured: if the first identifier indicates that the split tree structure is used for an internal image in the video sequence, and the second identifier indicates that CCLM can be performed on a chrominance block in the video sequence, performing all or part of the video sequence intra prediction method in the first aspect.

According to a fifth aspect, an embodiment of the present invention provides a decoding apparatus including a non-volatile memory and a processor that are coupled to each other, where the processor calls a program code stored in the memory to perform some or all of the method steps in either the first aspect or the second. aspect.

According to a sixth aspect, an embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium stores program code, and the program code includes instructions for performing some or all of the steps of the method in either the first aspect or the second aspect.

It should be understood that the technical solutions of the second to the sixth aspects of the present application are consistent with the technical solutions of the first aspect of the present invention, and the positive effects achieved by the aspects and the corresponding possible implementations are similar. This document does not re-describe the details.

Brief description of the drawings

In order to more clearly describe the technical solutions presented in the embodiments of the present invention or in the prior art, the accompanying drawings are briefly described below to describe the embodiments or the prior art. It is to be understood that the accompanying drawings provided in the following description only show some embodiments of the present invention, and a person skilled in the art can derive other drawings from these accompanying drawings without any creative effort.

Figure 1 shows a schematic representation of the CTU split mode;

Figure 2 shows a schematic representation of the separation mode of the chrominance block and the luma block;

Fig. 3 is a schematic representation of another mode of separation of a chrominance block and a luma block;

Fig. 4 is a block diagram of a video encoding and decoding system according to an embodiment of the present invention;

Fig. 5a is a block diagram of a video encoder according to an embodiment of the present invention;

Fig. 5b is a block diagram of a video decoder according to an embodiment of the present invention;

Fig. 5c is a block diagram of an example of an encoder or decoder according to an embodiment of the present invention;

Fig. 6 is a flowchart of an intra prediction method for a video sequence according to an embodiment of the present invention;

Fig. 7 is a flowchart of an intra prediction method for a video sequence according to an embodiment of the present invention;

Fig. 8 is a schematic structural diagram of an intra prediction apparatus according to an embodiment of the present invention; And

Fig. 9 is a schematic block diagram of an intra prediction apparatus according to an embodiment of the present invention.

Detailed description of the invention

Embodiments of the present application are described below with reference to the accompanying drawings.

First, the terms used in the present invention will be described.

Coding tree unit (CTU): A picture includes a plurality of CTUs, and one CTU typically corresponds to one square area of the picture and includes luma samples and chrominance samples in the picture area (or may include only luma samples, or may include only chrominance samples). The CTU further includes syntax elements. These syntax elements indicate how to divide the CTU into at least one coding unit (CU) and decode each coding unit to obtain a reconstructed image.

CU: CU typically corresponds to an A×B rectangular area and includes A×B luma samples and chrominance samples corresponding to luma samples, where A is the width of the rectangle, B is the height of the rectangle, and the width of A can be the same as the height of B or be different from it. The values A and B are typically integer powers of 2, such as 256, 128, 64, 32, 16, 8, and 4. The coding unit may be decoded to obtain a reconstructed image of the A×B rectangular area. The decoding processing typically includes performing processing such as prediction, dequantization, and inverse transformation to generate a prediction image and a residual. The reconstructed image is obtained by overlaying the prediction image and the residual.

Quadtree: A quadtree is a tree structure and a node can be split into four child nodes. The quadtree-based CTU partitioning mode is used in the H.265 video coding standard, where the CTU is used as the root node, and each node corresponds to one square area. Further division of the node is not possible (in which case the area corresponding to the node is CU), or the node is divided into four lower level nodes, i.e. the square area is divided into four square areas of equal size (where the length and width of each of the four square areas of equal size are half the length and width of the square area that was before splitting), and each area corresponds to one node, as shown in Fig. 1(a).

Binary Tree: A binary tree is a tree structure and a node can be split into two child nodes. In the existing coding method that uses a binary tree, a node in the binary tree structure cannot be split, or the node is split into two lower level nodes. A node is divided into two nodes in one of two ways: (1) horizontal binary partition: the region corresponding to a node is divided into two regions of the same size: an upper region and a lower region, and each region corresponds to one node, as shown in Fig. 1(b ); or (2) vertical binary partition: a region corresponding to a node is divided into two regions of equal size: a left region and a right region, and each region corresponds to one node, as shown in Fig. 1(c).

Ternary Tree: A ternary tree is a tree structure and a node can be split into three child nodes. In the existing ternary tree based coding method, a node in the ternary tree structure cannot be split, or the node can be split into three lower level nodes. A node is split into three nodes in one of two ways: (1) horizontal ternary split: the region corresponding to the node is divided into three regions: top region, middle region, and bottom region, and each region corresponds to one node, where the height of the top region, middle region and the lower region is 1/4, 1/2 and 1/4 of the height of the node, respectively, as shown in Fig.1(d); (2) vertical ternary division: the region corresponding to a node is divided into three regions: left region, middle region and right region, and each region corresponds to one node, where the width of the left region, middle region region and right region are 1/4, 1 /2 and 1/4 of the height of the node, respectively, as shown in Fig.1(f).

Versatile video coding test model (VTM): This is a codec reference software for the H.266 standard/versatile video coding test model (VVC) organized and developed by JVET.

Cross-component linear model intra prediction (CCLM) is a chrominance prediction method using luminance restoration sampling, such as CCLM technology in VTM5. In CCLM, the linear model parameters α and β are estimated using the reconstructed luminance sample and the reconstructed chrominance sample around the current chrominance block; after subsampling the reconstructed luma samples corresponding to the current chrominance block, prediction samples of the current chrominance block are obtained using a linear model as shown in formula 1:

, (1)

where α and β are the coefficients of the linear model, is the chroma sample predictor at position (i, j), and – values of the luminance restoration sample at position (i, j) after subsampling the luminance restoration block corresponding to the current chrominance block, before resolving the chrominance component. Note that for YUV4:2:0 video, the resolution of the luminance component is four times larger (twice the width and twice the height) than the resolution of the chrominance component. In order to obtain a luma block with the same resolution as a chrominance block, the luminance component must be downsampled to the chrominance resolution according to the same sampling method as the chrominance component and will be used further.

An intra sub-partition (ISP) is an intra sub-partition technology based on sub-block division, such as the ISP technology in VTM5. When using the ISP mode, a horizontal or vertical luminance block is divided into multiple (eg, two or four) luminance subblocks of the same size, and the luminance subblock is sequentially decoded and reconstructed. If a common intra prediction mode is used for a chrominance block (eg, angular prediction mode, planar prediction mode, or DC prediction mode), only reconstructed samples around the chrominance block are used for intra chroma prediction. In this case, chroma block intra prediction and luma block intra prediction can be performed simultaneously, the maximum delay in executing prediction processing in the chrominance block relative to the execution of prediction processing in the luminance block in the corresponding area (which is called chroma processing delay for short) is equal to the processing time to execute intra-prediction and reconstruction in a region including 0 luma samples. In one tree, the CU includes luma samples and chrominance samples. When CCLM is performed for chrominance sampling, it is necessary to use luma restoration sampling at the corresponding position. If the luminance block is divided into a plurality of sub-regions for sequential processing, after intra-prediction is performed in the luminance sub-region, predictors and residuals are superimposed to obtain the reconstructed samples of the luminance sub-region, and CCLM prediction can be performed in the chrominance sub-region at the corresponding position using the reconstructed samples brightness subregions. Thus, when a split tree structure is used for an intra image, if CCLM prediction is performed on a chrominance block, there may be a problem of a relatively large delay in chrominance signal processing.

For example, when a node luminance block whose size is 64×64 is divided using the quadtree split mode (as shown in FIG. 2(a)), the processing sequence of the four luminance nodes generated is node 0, node 1, node 2, and node 3. When a node chrominance block whose size is 64×64 is divided using the vertical binary splitting mode shown in FIG. required for CCLM prediction can only be obtained for chrominance node 0 after luma node 2 is reconstructed. The processing delay of the chroma signal is equal to the processing time of three luma regions whose size is 32×32 (that is, 3072 luma samples). As another example, when a node chrominance block whose size is 64x64 is divided into two chroma nodes using the horizontal binary tree shown in FIG. top side continues to be further split into two nodes using the horizontal binary tree mode, if CCLM prediction is performed on chroma node 0, all luma recovery sample values needed for CCLM prediction can be obtained for chroma node 0 only after luma node 1 is reconstructed, and the delay in processing the chrominance signal is equal to the processing time of two luma regions (ie 2048 luminance samples) whose dimensions are 32×32.

When some divisions are performed in a chrominance block of a node whose size is 64x64, the processing delay for performing CCLM on a chrominance node does not exceed the processing time of one luminance region whose size is 32x32. For example, when a luminance block whose size is 64×64 is divided using the quadtree split mode, if the corresponding chrominance block is also split using the quadtree split mode as shown in FIG. 2(d), CCLM may be performed on chroma node 0 after luma node 0 is restored, CCLM can be performed on chroma node 1 after luma node 1 is restored, and so on. As another example, if the chrominance block of a node whose size is 64×64 is not divided as shown in FIG. CCLM may be performed on chrominance region p0 after luma node 0 is restored, CCLM may be performed on chrominance region p1 after luma node 1 is restored, and so on. As another example, if a chrominance block of a node whose size is 64x64 is first divided using the horizontal split mode, a chroma node whose size is 64x32 is split on the top side using the vertical split mode, and a chroma node whose the size is 64×32, on the bottom side is not divided, as shown in Fig. 2(f), the delays in processing the chroma of chrominance nodes 0, 1 and 2 are each separately the delay in processing the luma region, whose size is 32×32. This is because CCLM can be performed on chroma node 0 after luma node 0 is restored, CCLM can be performed on chroma node 2 after luma node 1 is restored, CCLM can be performed on chroma node 2 region p0 after luma node 2 is completed, and CCLM can be performed on the chrominance region p1 node 2 after restoration of the luma node 3.

In addition, if a partition tree structure is used for the inner image when a 64×64 luminance block is not divided, and an ISP mode is used for the luma block, the delay in chroma processing may exceed the processing time of one luma region whose size is 32× 32. For example, when a node luminance block whose size is 64×64 is divided into four luma sub-blocks using the vertical ISP mode as shown in FIG. mode of horizontal binary separation as shown in Fig. 3(b), CCLM can be performed on chrominance node 0 only after four luma sub-blocks are reconstructed, and the chroma processing delay is equal to the processing time of four luma regions whose sizes are 32×32. Similarly, when the luminance block of a node whose size is 64×64 is divided into four luminance sub-blocks using the horizontal ISP mode as shown in FIG. using the vertical binary division mode as shown in FIG. 3(f), CCLM can be performed on chrominance node 0 only after four luma sub-blocks are reconstructed, and the chroma processing delay is equal to the processing time of four luminance regions whose dimensions are 32×32.

When some divisions are performed in a chrominance block of a node whose size is 64x64, even if a luminance block of 64x64 is not divided and the ISP mode is used for the luma block, the processing delay for performing CCLM by the chrominance node does not exceed the processing time of one luminance region , whose size is 32×32. For example, when the ISP vertical mode is used for a luminance block of a node whose size is 64×64, if the chrominance block of a node whose size is 64×64 is not divided as shown in FIG. 3(d), or a chrominance block of a node whose size is 64×64, split using vertical binary mode to obtain nodes whose sizes are 32×64, and nodes are split using vertical binary split mode or not split as shown in Fig. 3(c), signal processing delay chromaticity is equal to the processing time of one luminance region, whose size is 16×64, and can also be considered approximately equal to the processing time of one luminance region of 32×32 (both correspond to 1024 luma samples). More specifically, when a node chrominance block whose size is 64×64 is not divided, the chrominance block can be vertically divided into four sub-regions, and CCLM can start to be performed on each sub-region after the corresponding luma sub-block whose size is 16×64 is restored. If a chrominance block of a node whose size is 64x64 is split using vertical binary mode to obtain nodes of size 32x64, and the nodes are split using vertical binary split mode, CCLM may start to be executed on each chrominance node whose size is 16x 64 after restoring the corresponding luminance sub-block whose size is 16×64. When a node whose size is 32x64 is not divided horizontally, the node can be vertically divided into two 16x64 sub-regions, and CCLM can start to be performed on each sub-region after restoring the corresponding luminance sub-block whose size is 16x64. Similarly, when the ISP horizontal mode is used for a node luminance block whose size is 64×64, if the node chrominance block whose size is 64×64 is not divided as shown in FIG. 3(h), or the node chrominance block, whose size is 64×64 is divided using the horizontal binary partitioning mode to obtain nodes whose sizes are 64×32, and the nodes are separated using the horizontal binary partitioning mode or not separated, as shown in Fig. 3(g), the delay at chroma signal processing is equal to the processing time of one luminance region whose size is 64×16, and is equal to the processing time of one luma region whose size is 32×32.

Figure 4 shows a block diagram of an example of a video coding system 4 described in an embodiment of the present application. In this specification, the term "video codec" generally refers to a video encoder and a video decoder. In this application, the term "video coding" or "coding" can generally refer to video coding or video decoding. Video encoder 100 and video decoder 300 in video coding system 1 are configured to predict motion information, such as a motion vector, a current encoded picture block, or a sub-block of a current encoded picture block, using various exemplary methods described in any of the many new intra prediction modes provided. in the present application so that the predicted motion vector is as close as possible to the motion vector obtained using the motion estimation method. Thus, it is not necessary to transmit the motion vector difference during encoding, which further improves the performance of encoding and decoding.

As shown in FIG. 4, the video encoding system 1 includes a source device 10 and a destination device 30. The source device 10 generates encoded video data. Thus, the source device 10 may be referred to as a video encoding device. Destination device 30 may decode encoded video data generated by source device 10. Thus, destination device 30 may be referred to as an intra video prediction device. Source device 10, destination device 30, or various implementations of source device 10 and destination device 30 may include one or more processors and memory coupled to one or more processors. Memory may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or any other storage medium that can be used to store the desired program code in the form of an instruction or data structure accessible to a computer, as described herein. .

Source device 10 and destination device 30 may include a variety of devices, including a desktop computer, a mobile computing device, a laptop computer (for example, a laptop computer), a tablet computer, a set-top box, a portable telephone such as a smart phone. telephone (smartphone), TV, camera, display device, digital media player, game console, car computer or similar device.

Destination device 30 may receive encoded video data from source device 10 over link 50 . Link 50 may include one or more media or devices that can transmit encoded video data from source device 10 to destination device 30. For example, link 50 may include one or more media that allows the device to -source 10 directly send encoded video data to destination device 30 in real time. In this example, source device 10 may modulate encoded video data in accordance with a communication standard (eg, a wireless communication protocol) and may send the modulated video data to destination device 30. One or more transmission media may include a wireless communication medium and/or a wired communications, such as the radio frequency (RF) spectrum or one or more physical transmission cables. One or more transmission media may be part of a packet network, and the packet network is, for example, a local area network, a regional network, or a wide area network (eg, the Internet). One or more transmission media may include a router, switch, base station, or other device that provides communication between source device 10 and destination device 30.

In another example, encoded data may be output to storage device 40 via output interface 140. Similarly, encoded video data may be accessed from storage device 40 via input interface 340. Storage device 40 may include any one of a variety of distributed or locally available storage media such as a hard drive, Blu-ray disc, DVD, CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium capable of storing encoded video data.

In another example, storage device 40 may correspond to a file server or other intermediate storage device that can support encoded video generated by source device 10. Destination device 30 may access stored video data from storage device 40 via streaming or downloading. The file server may be any type of server that can store the encoded video data and that sends the encoded video data to the destination device 30. For example, the file server may be a network server (e.g., used for a website), an FTP server, a network storage (NAS ) or local disk. The recipient device 30 can access the encoded video data via any standard data connection (including an Internet connection). A typical data connection may include a wireless link (eg, a Wi-Fi connection), a wired connection (eg, DSL or cable modem), or a combination thereof that is suitable for accessing encoded video data stored in a file server. The transmission of the encoded video data from the storage device 40 may be a streaming transmission, a transmission-download, or a combination thereof.

The motion vector prediction technology of the present application can be used to encode and decode video so as to support a variety of multimedia applications such as terrestrial television, cable television transmission, satellite television transmission, video streaming (e.g., over the Internet), video data coding, stored on a storage medium, decoding video data stored on a storage medium, or other applications. In some examples, the video coding system 1 may be configured to support unidirectional or bidirectional video transmission to support applications such as video streaming, video playback, video broadcasting, and/or video telephony.

The video encoding system 1 described in FIG. 4 is merely an example, and the technology in the present application is applicable to a video encoding device (e.g., video encoding or video decoding), which does not necessarily include any communication between the video encoding device and the device. video decoding. In other examples, data is retrieved from local memory, transferred over a network, and the like. The video encoding device may encode the data and store the data in memory, and/or the video decoding device may retrieve the data from the memory and decode the data. In many examples, devices that only encode data and store data in memory and/or retrieve data from memory and decode data, and that do not communicate with each other, perform encoding and decoding.

In the example shown in FIG. 4, source device 10 includes video source 120, video encoder 100, and output interface 140. In some examples, output interface 140 may include a modulator/demodulator (modem) and/or a transmitter. Video source 120 may include a video capture device (eg, a camera), a video data archive including previously captured video data, a video input interface for receiving video data from a video content provider, and/or a computer graphics system for generating video data, or a combination of the above video data sources. .

Video encoder 100 may encode video data that is received from video source 120. In some examples, source device 10 directly sends the encoded video data to destination device 30 via output interface 140. Alternatively, in another example, the encoded video data may be stored in storage device 40 so that destination device 30 can subsequently access the encoded video data. for decoding and/or playback.

In the example shown in FIG. 4, the sink device 30 includes an input interface 340, a video decoder 300, and a display device 330. In some examples, input interface 340 includes a receiver and/or a modem. Input interface 340 may receive encoded video data via communication channel 30 and/or from storage device 40. Display device 330 may be integrated with sink device 30 or may be located outside of sink device 30. Display device 330 typically displays decoded video data. The display device 330 may include many types of display devices, such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

Although not shown in FIG. 4, in some aspects, video encoder 100 and video decoder 300 may be integrated with an audio encoder and audio decoder, respectively, and may include an appropriate multiplexer-demultiplexer (MUX-DEMUX) unit or other hardware. and software for encoding audio and video in a common data stream or in a separate data stream. In some examples, if applicable, the MUX-DEMUX block may conform to the ITU H.223 Multiplexer Protocol or another protocol, such as User Datagram Protocol (UDP).

Each of video encoder 100 and video decoder 300 may be implemented, for example, in any of the following variety of circuits: one or more microprocessors, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), discrete logic , hardware, or any combination thereof. If the present application is implemented in part by software, the device may store, on an appropriate non-volatile computer-readable storage medium, the instruction used for the software and may use one or more processors to execute the instruction in hardware to implement the technology presented in this application. . Any of the above components (including hardware, software, a combination of hardware and software, and the like) can be considered one or more processors. Each of video encoder 100 and video decoder 300 may be included in one or more encoders or decoders, and either the encoder or decoder may be integrated into a combined encoder/decoder (codec) part in a respective device.

In this application, video encoder 100 may be generically referred to as another device "signaling" or "sending" some information to, for example, video decoder 300. The term "signaling" or "transmission" may be generically referred to as the transmission of a syntax element and/or other data used to decode the compressed video data. The transmission may take place in real time or near real time. Alternatively, communication may occur after a certain period of time has elapsed, for example, may occur when a syntax element in the encoded bitstream is stored on a machine-readable storage medium during encoding, and then the intra predictor can extract the syntax element at any time after the syntax element will be stored on the storage medium.

Video encoder 100 and video decoder 300 may operate in accordance with a video compression standard, such as High Efficiency Video Coding (HEVC) or an extension thereof, and may conform to the HEVC test model (HM). Alternatively, video encoder 100 and video decoder 300 may function in accordance with other industry standards, such as ITU-T H.264 and H.265, or extensions of these standards. However, the technologies in this application are not limited to any particular encoding and decoding standards.

FIG. 5a shows a schematic/conceptual block diagram of an example video encoder 100 capable of implementing the technology (disclosed) in this application. In the example of FIG. 5a, video encoder 100 includes a residual calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block 210, an inverse transform processing block 212, a reconstruction block 214, a buffer 216, a loop filter block 208, a buffer 230 decoded picture buffer (DPB), block 260 processing prediction and block 270 entropy encoding. The prediction processing unit 260 may include an intra prediction unit 244 , an intra prediction unit 254 , and a mode selection unit 262 . The intra prediction block 244 may include a motion estimator and a motion compensation block (not shown in the figure). The video encoder 100 shown in FIG. 5a may also be referred to as a hybrid video encoder or a hybrid video codec-based video encoder.

For example, the residual calculation block 204, the transform processing block 206, the quantization block 208, the prediction processing block 260, and the entropy encoding block 270 form a direct signal path of the encoder 100, while, for example, the inverse quantization block 210, the inverse transform processing block 212, block 214 recovery buffer 216, loop filter 220, decoded picture buffer (DPB) 230, and prediction processor 260 form an encoder signal return path, where the video encoder return signal path corresponds to the decoder signal path (see video decoder 300 in FIG. 5b) .

The encoder 100 receives, for example, via input 202 an image 201 or a block 203 of an image 201, for example an image as a sequence of images constituting a video or video sequence. Image block 203 may also be referred to as the current image block or image block to be encoded, and image 201 may be referred to as the current image or image to be encoded (particularly in video encoding, to distinguish the current image from other images, such as previously encoded and/or or decoded pictures in the same video sequence, namely a video sequence that also includes the current picture).

Division into sections

In an embodiment, the encoder 100 may include a splitter (which is not shown in FIG. 5a) configured to split the image 201 into a plurality of blocks, such as blocks 203. The image 201 is typically divided into a plurality of non-overlapping blocks. The partition block can be configured to: use the same block size for all images of the video sequence and the corresponding grid defining the block size, or change the block size between images or subsets or groups of images and divide each image into appropriate blocks.

In one example, prediction processing unit 260 of video encoder 100 may be configured to perform any combination of the aforementioned separation techniques.

Similar to image 201, block 203 is also or may be considered as a two-dimensional array or matrix of samples with brightness values (sample values), although the size of block 203 is smaller than the size of image 201. In other words, block 203 may include, for example, one array of samples ( eg, a luminance array in the case of a monochrome image 201), three sample arrays (eg, one luminance array and two chrominance arrays in the case of a color image), or any other number and/or any other type of arrays depending on the color format used. The number of samples in the horizontal and vertical directions (or axes) of block 203 determines the size of block 203.

The encoder 100 shown in Fig. 5a is configured to encode the image 201 block by block, for example, to encode and predict each block 203.

Remainder Calculation

The residual calculator 204 is configured to calculate the residual block 205 based on the image block 203 and the predictor 265 (details on the predictor 265 are further provided below), for example, by subtracting the sample values of the predictor 265 from the sample values of the image block 203 based on "sample sample by sample to obtain a residual block 205 in the sample area.

transformation

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

Transform processing unit 206 may be configured to apply DCT/DST integer approximations such as the transforms specified in HEVC/H.265. Compared to the orthogonal DCT, such integer approximations are usually scaled by a factor. To preserve the norm of the residual block that is processed using forward and inverse transforms, an additional scaling factor is applied as part of the transform process. The scaling factor is usually chosen based on some constraints, such as a scaling factor of a power of two for the shift operation, the bit depth of the transform factor, and a trade-off between accuracy and implementation cost. For example, a specific scaling factor is specified for the inverse transform, for example, by the inverse transform processing unit 212 at the decoder 30 side (and for the corresponding inverse transform, for example, by the inverse transform processing unit 212 at the encoder 20 side), and accordingly, the corresponding scaling factor may be set for direct conversion by the conversion processing unit 206 on the side of the encoder 20.

Quantization

Quantizer 208 is configured to quantize transform coefficients 207 to obtain quantized transform coefficients 209, for example by applying scalar quantization or vector quantization. The quantized transform coefficient 209 may also be referred to as the quantized residual coefficient 209 . The quantization process allows the bit depth related to some or all of the transform coefficients 207 to be reduced. For example, an n-bit transform coefficient may be rounded to an m-bit transform coefficient during quantization, where n is greater than m. The degree of quantization can be changed by adjusting the quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to finer quantization, and a larger quantization step size corresponds to coarser quantization. The appropriate quantization step size may be indicated by a quantization parameter (QP). For example, the quantization parameter may be an index to a given set of suitable quantization step sizes. For example, a smaller quantization parameter may correspond to finer quantization (smaller quantization step size), and a larger quantization parameter may correspond to coarser quantization (larger quantization step size), or vice versa. Quantization may include dividing by the quantization step size and corresponding quantization or dequantization, such as performed by inverse quantizer 210, or may include multiplying by the quantization step size. Embodiments according to some standards, such as HEVC, may use a quantization parameter to determine the quantization step size. Typically, the quantization step size can be calculated based on the quantization parameter using a fixed-point approximation of an equation involving division. Additional scaling factors may be introduced for quantization and dequantization to recover the residual block norm, which may be modified due to the scaling used in the fixed-point approximation of the equation for quantization step size and quantization parameter. In one exemplary implementation, inverse transform scaling and dequantization may be combined. Alternatively, individual quantization tables may be used and signaled from the encoder to the decoder, eg in a bitstream. Quantization is a lossy operation where the loss increases as the quantization step size increases.

The inverse quantizer 210 is configured to apply the inverse quantization of the quantizer 208 to the quantized coefficients in order to obtain the dequantized coefficients 211, e.g. quantization applied by the quantizer 208 . The dequantized coefficients 211 may also be referred to as the dequantized residual coefficients 211 and correspond to the transform coefficients 207, although they are usually not identical to the transform coefficients due to losses caused by quantization.

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

The restorer 214 (eg, adder 214) is configured to add the inverse transform block 213 (ie, the reconstructed residual block 213) to the predictor 265, for example, by adding the sample values of the reconstructed residual block 213 and the sample values of the predictor 265, in order to to get a reconstructed block 215 in the sample area.

If necessary, buffer block 216 (or "buffer" 216 for short), such as string buffer 216, is configured to buffer or store the reconstructed block 215 and the corresponding sample value, for example, for intra-prediction. In other embodiments, the encoder may be configured to use the unfiltered reconstructed block and/or the corresponding sample value stored in buffer block 216 for any type of estimation and/or prediction, such as intra prediction.

For example, in an embodiment, encoder 100 may be configured such that buffer block 216 is not only used to store reconstructed block 215 for intra prediction 254, but is also used for loop filter block 220 (which is not shown in FIG. 5a), and/ or such that, for example, the buffer block 216 and the decoded picture buffer block 230 form one buffer. In other embodiments, filtered blocks 221 and/or blocks or samples from decoded picture buffer 230 (blocks or samples not shown in FIG. 5a) are used as input or basis for intra prediction 254.

The loop filter block 220 (or "loop filter" 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, thereby smoothing transitions between samples or improving video quality. The loop filter block 220 is designed to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or another filter, such as a two-sided filter, an adaptive loop filter (ALF). , a sharpening or smoothing filter, or a combined filter. Although the loop filter block 220 is shown in FIG. 5a, in another configuration, the loop filter block 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as the filtered reconstructed block 221. The decoded picture buffer 230 may store the reconstructed coded block after the loop filter block 220 performs a filtering operation on the reconstructed coded block.

In an embodiment, encoder 100 (respectively, loop filter block 220) may be configured to output a loop filter parameter (such as adaptive sample bias information), for example, directly or after entropy encoding performed by entropy encoding block 270 or any other entropy block. coding, so the decoder 30 may receive, for example, the same loop filter parameter and apply the same loop filter parameter for decoding.

The decoded picture buffer (DPB) 230 may be a reference picture memory that stores reference picture data for use in encoding video data by video encoder 100. The DPB 230 may be formed using any of a variety of storage devices such as dynamic random access memory (dynamic random access memory, DRAM) (including synchronous DRAM (synchronous DRAM, SDRAM), magnetoresistive RAM (magnetoresistive RAM, MRAM), resistive RAM (resistive RAM, RRAM)) or other types of storage devices. DPB 230 and buffer 216 may be implemented using the same storage device or separate storage devices. In an example, the decoded picture buffer (DPB) 230 230 is configured to store the filtered block 221. The decoded picture buffer 230 may be further configured to store other previously filtered blocks, such as previously restored and filtered blocks 221, of the same of the current picture or different pictures, e.g., previously reconstructed pictures, and may provide completely previously reconstructed pictures, i.e., decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current picture (and corresponding reference blocks and samples), for example, for internal forecasting. In one example, if the reconstructed block 215 is reconstructed without in-loop filtering, the decoded picture buffer (DPB) 230 is configured to store the reconstructed block 215.

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

Mode selector 262 may be configured to select a prediction mode (e.g., intra or intra prediction mode) and/or an appropriate predictor 245 or 255 to be used as predictor 265 to calculate residual block 205 and to reconstruct the reconstructed block. 215.

In an embodiment, the mode selector 262 may be configured to select a prediction mode (e.g., from among the prediction modes supported by the prediction processing unit 260) where the prediction mode provides the best match or, in other words, the minimum residual (the minimum residual value means the best compression for transmission or storage), or provides minimal signaling overhead (lowest signaling overhead means better compression for transmission or storage), or considers or balances both. The mode selector 262 may be configured to determine a prediction mode based on rate distortion optimization (RDO), namely, selecting a prediction mode that provides minimum rate distortion optimization, or selecting a prediction mode for which the rate distortion is at least least satisfies the criterion for selecting the prediction mode.

The following is a more detailed description of the prediction process performed (for example, using the prediction processing block 260) and mode selection (for example, using the mode selection block 262) using the encoder 100 as an example.

As described above, encoder 100 is configured to determine or select the best or optimal prediction mode from a set of (given) prediction modes. The set of prediction modes may include, for example, an intra prediction mode and/or an intra prediction mode.

The set of intra prediction modes may include 35 different intra prediction modes, such as non-directional modes such as DC (or average) mode and planar mode, or directional modes such as those defined in H.265, or may include 67 various intra prediction modes, such as non-directional modes such as DC (or average) mode and planar mode, or directional modes such as those defined in H.266 under development.

The set of intra prediction modes (possibly) depends on the available reference picture (i.e., at least part of the decoded picture stored in DBP 230) and another intra prediction parameter, for example, depending on whether the entire reference picture is used, or whether only a portion of the reference image, such as the search window area around the current block area, to find the most suitable reference block, and/or depending on, for example, whether sample interpolation is applied, such as half-sample and/or quarter-sample interpolation.

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

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

The intra prediction block 244 may include a motion estimation (ME), a block (which is not shown in FIG. 5a), and a motion compensation (MC) block (which is not shown in FIG. 5a). The motion estimator is configured to receive or obtain an image block 203 (the current block 203 of the current image 201) and a decoded image 231 or at least one or more previously reconstructed blocks, such as one or more reconstructed blocks of other/different previously decoded images 231 for movement estimates. For example, the video sequence may include the current picture and previously decoded pictures 31. In other words, the current picture and previously decoded pictures 31 may be part of, or may form, a sequence of pictures forming a video sequence.

For example, encoder 100 may be configured to select a reference block from a plurality of reference blocks of the same picture or different pictures from a plurality of other pictures and provide them to a motion estimator (which is not shown in FIG. 5a), a reference picture, and /or an offset (spatial offset) between the position (with X and Y coordinates) of the reference block and the position of the current block as an intra prediction parameter. Displacement is also called motion vector (MV).

The motion compensation block is configured to obtain, for example, an intra prediction parameter and perform intra prediction based on or using the intra prediction parameter to obtain the intra prediction block 245 . The motion compensation performed by the motion compensation block (which is not shown in FIG. 5a) may include sampling or generating a prediction block based on the motion vector/block determined by the motion estimation (possibly by performing subsampling interpolation). Interpolation filtering allows additional samples to be generated from known samples, thereby potentially increasing the number of potential prediction blocks that can be used to encode an image block. After receiving the motion vector for the PU of the current picture block, the motion compensator 246 may find the prediction block pointed to by the motion vector in one of the reference picture lists. Motion compensator 246 may also generate syntax elements associated with video blocks and tiles for use by video decoder 300 when decoding image blocks of a video clip.

The intra predictor 254 is configured to obtain, for example, receive, an image block 203 (the current image block) and one or more previously reconstructed blocks, such as reconstructed adjacent blocks, from the same image for intra estimates. Encoder 100 may be, for example, configured to select an intra prediction mode from a plurality of (given) intra prediction modes.

In an embodiment, encoder 100 may be configured to select an intra prediction mode based on an optimization criterion, such as a minimum residual (eg, based on an intra prediction mode providing a prediction block 255 that is most similar to the current picture block 203) or a minimum speed distortion.

The intra predictor 254 is further configured to determine the intra predictor 255 based on, for example, an intra prediction parameter in the selected intra prediction mode. In any case, after the block intra prediction mode is selected, the intra prediction block 254 is further configured to provide an intra prediction parameter, that is, information indicating the selected block intra prediction mode, to the entropy encoding block 270 . In an example, intra predictor 254 may be configured to perform any combination of intra prediction technologies described below.

The entropy encoding unit 270 is configured to apply (or not apply) an entropy encoding algorithm or scheme (e.g., variable length coding (VLC) scheme), context adaptive VLC scheme (context adaptive VLC, CAVLC), arithmetic coding scheme , context-adaptive binary arithmetic coding (CABAC), based on the syntax of context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy, PIPE) or other entropy coding methodology or technology) to one or all of the quantized residual coefficients 209, an intra prediction parameter, an intra prediction parameter, and/or a loop filter parameter to obtain encoded image data 21 that can be output via output 272, for example, in the form encoded bitstream 21. The encoded bitstream may be passed to video decoder 300, or archived for later transmission, or retrieved by video decoder 300. Entropy encoding unit 270 may be further configured to entropy encode a different syntax element for the currently encoded video fragment.

Other structural variations of video encoder 100 may be used to encode the video stream. For example, non-transform-based encoder 100 may quantize the residual signal directly without transform processing unit 206 for some blocks or frames. In another implementation, encoder 100 may have quantizer 208 and inverse quantizer 210 combined into a single unit.

5b shows a block diagram of a video decoder according to an embodiment of the present invention. Entropy decoder 303 of video decoder 300 entropy decodes the bitstream to produce a quantized coefficient and some syntax elements. The entropy decoder 303 directs the syntax elements to the prediction processing block 308 . Video decoder 300 may receive syntax elements/syntax element at the video fragment level and/or at the picture block level. In the present application, in the example, the syntax element herein may include intra prediction data related to a chroma coding tree node, the intra prediction data may include a first qtbtt_dual_tree_intra_flag identifier and a second sps_cclm_enabled_flag identifier, the first identifier is used to indicate whether whether the splitting tree structure for an inner picture in the video sequence, and the second identifier is used to indicate whether to allow CCLM to be performed on a chrominance block in the video sequence. If necessary, the intra prediction data may further include a size and split flag of the chroma coding tree node, and the split flag may be set to different values to indicate that different split modes are used for the chroma coding tree node. If necessary, another syntax element may be additionally included.

Entropy decoder 303 entropy decodes the bitstream to obtain a first ID qtbtt_dual_tree_intra_flag and a second ID sps_cclm_enabled_flag. If the first identifier indicates that a split tree structure is used for an internal picture, and the second identifier indicates that CCLM can be performed on a chrominance block in the video sequence, the entropy decoder 303 continues to parse the size and split flag of the chroma coding tree node from the bitstream, and the internal predictor 309 determines the split mode of the chrominance coding tree node based on the split flag, and determines, based on the size and split mode of the chroma coding tree node, whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node. The entropy decoder 303 parses the first CuPreMode index of the chrominance coding unit from the bitstream. If the value of the first index is MODE_INTRA, the entropy decoder 303 continues to parse the third identifier pcm_flag from the bitstream. If the third identifier indicates that the PCM mode is not used for the chroma coding unit, the entropy decoder 303 parses the second intra_chroma_pred_mode index from the bitstream. The intra predictor 309 determines the chroma coding unit prediction mode based on the second intra_chroma_pred_mode index and the luma coding unit prediction mode corresponding to the chroma coding unit, and then performs intra chroma coding unit prediction based on the chroma coding unit prediction mode to obtain chroma coding unit prediction samples. The entropy decoder 303 further parses the bitstream to obtain information about the remainder of the chroma coding unit.

The dequantizer 304 and the inverse converter 305 process the chroma coding unit residual information to obtain the recovered chrominance coding unit residuals.

After the inner predictor 309 generates the prediction samples used for the chroma coding unit, the video decoder 300 adds the recovered residuals from the inverse transform 305 and the prediction samples generated by the inner predictor 310 to obtain the recovered chroma coding unit samples, i.e., the decoded picture block. The adder 311 is a component that performs the addition operation. If necessary, a loop filter (during or after the decoding cycle) can be additionally used to smooth transitions between samples or otherwise improve video quality. The filter block 306 may be one or more loop filters, such as a deblocking filter, an adaptive loop filter (ALF), and an adaptive sample bias (SAO) filter. Although the filter block 306 is shown in FIG. 5b, in another implementation, the filter block 306 may be implemented as a post-loop filter. In one example, filter block 306 may be applied to block reconstruction to reduce block distortion, and this result is output as a decoded video stream. In addition, a decoded picture block in a given frame or picture may be further stored in the decoded picture buffer 307, and the decoded picture buffer 307 stores a reference picture used for subsequent motion compensation. The decoded image buffer 307 may be part of a memory and may further store decoded video for later presentation on a display device (eg, display device 330 shown in FIG. 4). Alternatively, the decoded picture buffer 307 may be separate from such a memory.

It should be understood that another design of video decoder 300 may be used to decode the encoded video bitstream. For example, video decoder 300 may generate an output video stream without being processed by filter block 306 . Alternatively, for some image blocks or image frames, the entropy decoder 303 of the video decoder 300 does not obtain the quantized coefficient through decoding, and thus does not need to be processed by the dequantizer 304 and the inverse transform 305.

FIG. 5c shows a simplified block diagram of a device 500 that can be used as one or two of the source device 10 and the sink device 30 shown in FIG. 4, according to an exemplary embodiment. Device 500 enables the implementation of the technologies of the present application. Device 500 may be implemented as a computing system including a plurality of computing devices, or as a single computing device such as a mobile phone, tablet computer, laptop computer, or desktop computer.

Processor 502 of device 500 may be a central processing unit. Alternatively, processor 502 may be any other type of device or a plurality of devices that can control or process information that exist or will be developed in the future. As shown in the drawing, while the disclosed implementations may be practiced with a single processor, such as processor 502, speed and efficiency advantages may be achieved by using more than one processor.

In an implementation, memory 504 of device 500 may be read only memory (random access memory, ROM) or random access memory (RAM). The memory 504 may be any other suitable type of storage device. Memory 504 may include code and data 506 accessed by processor 502 using bus 512. Memory 504 may further include an operating system 508 and application programs 510. Application programs 510 include at least one program that allows processor 502 to perform the methods described herein. For example, applications 510 may include applications 1-N, and applications 1-N further include a video encoding application that performs the method described herein. Device 500 may also include additional memory in the form of secondary storage 514. Secondary storage 514 may be, for example, a memory card used with a mobile computing device. Since video communications may contain a large amount of information, all or part of this information may be stored in secondary storage 514 and loaded into memory 504 as needed for processing.

The device 500 may also include one or more output devices, such as a display 518. In an example, the display 518 may be a touch display that combines a display with a touch element that can accept touch inputs. Display 518 may be connected to processor 502 via bus 512. Other output devices that allow a user to program or otherwise use device 500 may be provided in addition to or alternative to display 518. When an output device is or includes a display, The display may be implemented in various ways, including liquid crystal display (LCD), cathode ray tube display (CRT), plasma display, or light emitting diode (LED) display, such as organic light emitting diodes (OLED, OLED).

Device 500 may also include or be connected to an image sensing device 520. The image pickup device 520 is, for example, a camera or any other image pickup device 520 that can sense an image and that exists or will be developed in the future. The image is, for example, an image of the user who triggers the device 500. The image pickup device 520 may be placed directly in front of the user who triggers the device 500. In an example, the position and optical axis of the image pickup device 520 may be configured such that the field of view of the device 520 image perception included an area located in close proximity to the display 518, and the display 518 can be seen from this area.

The sensing device 500 may also include an audio sensing device 522, such as a microphone or any other sound sensing device that exists or will be developed in the future, that can sense sounds near the device 500. The audio sensing device 522 may be placed directly in front of the user. , which starts the device 500 and may be configured to receive a sound, such as a voice or other sound, made by the user when the device 500 is started.

Although FIG. 5c shows processor 502 and memory 504 of device 500 integrated into a single unit, other configurations may be used. The operation of the processor 502 may be distributed among a plurality of machines (each machine having one or more processors), which may be directly connected or distributed over a local area or other network. Memory 504 may be distributed across multiple machines, such as network storage or memory across multiple machines running device 500. Although a single bus is shown herein, bus 512 of device 500 may include multiple buses. In addition, secondary storage 514 may be directly connected to other components of the device 500 or may be accessed over a network and may include one integrated unit, such as a memory card, or multiple units, such as a plurality of memory cards. Thus, device 500 can be implemented in a wide variety of configurations.

It should be noted that the encoder shown in Fig. 5a, the decoder shown in Fig. 5b, and the apparatus shown in Fig. 5c may perform some or all of the following embodiments of the method shown in Fig. 6 and Fig. 7.

FIG. 6 is a flowchart of an intra prediction method for a video sequence according to an embodiment of the present invention. As shown in Fig.6, the method includes the following steps.

S601. Get the size and splitting mode of a chroma coding tree node.

In particular, the corresponding syntax element in the bitstream is parsed to obtain the size and splitting mode of the chroma coding tree node. The chroma coding tree node splitting mode may include at least one of no splitting, quadtree splitting, horizontal binary splitting, horizontal ternary splitting, vertical binary splitting, and vertical ternary splitting. Of course, another splitting mode can be used as an alternative. The present invention is not limited to this.

It should be noted here that the video sequence format in this embodiment of the present invention may be YUV4:2:0 format, YUV4:2:2 format, or YUV4:2:4 format.

S602. Determining, based on the size and split mode of the chrominance coding tree node, as to whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node.

The chrominance coding unit included in the chrominance coding tree node is the chrominance coding unit in the image area corresponding to the chrominance coding tree node. If the chroma coding tree node is not split, the chroma coding tree node includes one chroma coding unit. If a chroma coding tree node is divided into child nodes, the chroma coding unit included in the chroma coding tree node is the chroma coding unit corresponding to all leaf nodes of the coding tree of the chroma coding tree node.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and the determination, based on the size and split mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node would further be included in myself:

when M and N are equal to a predetermined threshold T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes a non-split mode or a quadtree split mode, and the threshold T1 is, for example, 64 or 32; or

when M is T1 and N is T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining a CCLM resolution over the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

More specifically, when the first predetermined condition is non-split mode or quadtree split mode, "if the split mode of the chroma coding tree node satisfies the first predetermined condition" is "if the split mode of the chroma coding tree node is non-split mode or quadtree split mode". When the second predetermined condition is non-split mode or vertical binary split mode, "if the split mode of the chroma coding tree node satisfies the second predetermined condition" is "if the split mode of the chroma coding tree node is non-split mode or vertical binary split mode". In another exemplary embodiment, the first given condition may alternatively be a non-split mode, a quadtree split mode, or a horizontal binary split mode. In another possible embodiment, the second predetermined condition may alternatively be a non-split mode, a vertical binary split mode, or a horizontal binary split mode.

If the current chroma coding tree node is not divided, the encoding mode information of the chroma coding unit included in the current chroma coding tree node is further parsed, and decoding and reconstruction are completed. Otherwise, the current node of the chroma coding tree is split into a plurality of nodes based on the splitting mode of the current node of the chroma coding tree.

Here, it should be noted that if a splitting tree structure is used for the intra picture, a T1×(T1/2) chrominance coding tree node can only be obtained by splitting a T1×T1 chrominance coding tree node using the horizontal binary splitting mode; thus that "the chroma coding tree node size is T1×(T1/2)" is equivalent to the split mode of the parent node (that is, the chroma coding tree node whose size is T1×T1) of the chrominance coding tree node is the horizontal binary mode. separation.

For example, the chroma coding tree node size is assumed to be 64x64. When the chroma coding tree node luminance block whose size is 64×64 is divided using the quadtree split mode as shown in FIG. for a chrominance block of a chrominance coding tree node as shown in FIG. 2(d), CCLM may be performed on chroma node 0 after luminance node 0 is restored, CCLM may be performed on chrominance node 1 after luma node 1 is restored, and so on. As another example, if the division mode of the chroma coding tree node is not division, that is, the chroma block of the chroma coding tree node is not divided as shown in FIG. and p3, and intra-prediction p0, p1, p2 and p3 are performed sequentially. CCLM may be performed on chrominance region p0 after luma node 0 is restored, CCLM may be performed on chrominance region p1 before luma node 1 is restored, and so on.

If the chroma block of a chrominance coding tree node whose size is 64×64 is first divided using the horizontal binary separation mode, the chroma node whose size is 64×32 is divided at the top using the vertical binary separation mode, and the chrominance node whose size is 64×32, undivided at the bottom as shown in FIG. 2(f), CCLM can be performed on chroma node 0 after luma node 0 is restored, CCLM can be performed on chroma node 1 after luma node 1 is restored, CCLM can be performed on the region p0 of the chroma node 2 after the restoration of the luma node 2, and CCLM may be performed on the region p1 of the chrominance node 2 after the restoration of the luminance node 3. Thus, when a chrominance block of a chrominance coding tree node whose size is 64x64 is not divided or divided using the quadtree splitting mode, or a chroma block of a chroma coding tree node whose size is 64x32 is not divided or divided using the quadtree split mode vertical binary separation, the processing delay for performing CCLM on a chrominance node does not exceed the processing time of one luma region whose size is 32×32.

In this embodiment, the split mode that can be used by the luma coding tree node whose size is T1×T1 may be limited to include only the non-split mode and the split quadtree mode. This constraint can be implemented with the constraint that the maximum size of a binary tree node (for example, MaxBtSizeY in VTM5) of an I-frame image cannot exceed T1/2, and the maximum size of a ternary tree node (for example, MaxTtSizeY in VTM5) cannot exceed T1/2.

In addition, the ISP mode is not used for a luminance coding unit whose size is T1×T1 and which is included in the luminance coding tree node corresponding to the chrominance coding tree node.

In an exemplary embodiment, based on the size and partitioning mode of the chroma coding tree node, it is determined whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node. In addition, it is further determined whether to allow CCLM to be performed on the chrominance coding unit included in the chroma coding tree node based on the division mode of the luma coding tree node corresponding to the chroma coding tree node.

In an exemplary embodiment, determining, based on the size and split mode of a chrominance coding tree node, as to whether to allow inter-component linear model (CCLM) intra prediction to be performed on a chroma coding unit included in a chroma coding tree node includes:

determining, based on the size and splitting mode of the chroma coding tree node, the splitting mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the inner subsection for the corresponding luma block, and when the luma coding tree node is not split whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node, where the case where the luma coding tree node is not divided corresponds to one luminance coding unit; therefore, the luminance block corresponding to the case where the luminance coding tree node is not divided is the luminance block of the luminance coding unit corresponding to the luminance coding tree node.

The luma coding tree node corresponding to the chrominance coding tree node is a luminance coding tree node whose size is T1×T1 in the luminance coding tree in the partition tree in which the chrominance coding tree is located. For example, when a split tree is used for an internal image in VVC project 5, a 64×64 coding tree node is split using a split tree, and the split tree includes a luminance coding tree and a chrominance coding tree. If T1 is set to 64, the luminance coding tree node corresponding to the chrominance coding tree node is the root node of the luma coding tree of the partition tree in which the chrominance coding tree is located.

In an exemplary embodiment, the size of the chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node, the split mode of the luminance coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode of the internal subsection for the corresponding luma block when the luminance coding tree node is not split, and whether to allow CCLM execution on the chroma coding unit included in the chroma coding tree node includes:

when the split mode of the chroma coding tree node satisfies any one condition in the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit;

when the division mode of the chroma coding tree node does not satisfy the third predetermined condition, M is T1, and N is T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes a non-split mode or a quadtree split mode; or

when the division mode of the chroma coding tree node does not satisfy the third predetermined condition, M is T1, N is T1/2, if the division mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an embodiment, the third predetermined condition includes one or any combination of the following conditions 1-13 and 1-13:

Condition 1: The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the ISP mode is used for the luma block of the luminance coding tree node, where the size of the luminance coding tree node is T1×T1 (where the luminance coding tree node and the node chroma coding trees belong to the same partition tree, i.e., the coordinates of the upper left corner of the luminance coding tree node are the same as the coordinates of the upper left corner of the root node of the chroma coding tree).

Condition 2: The division mode of the luminance coding tree node corresponding to the chrominance coding tree node is not partitioning, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes, where each of the size of the chroma coding tree node, the node size of the luminance coding tree and the size of the luma block is T1×T1.

Condition 3: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not partitioning, the horizontal ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the vertical binary splitting mode, a vertical ternary splitting mode or a quadtree splitting mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luma block size is each T1×T1.

Condition 4: The division mode of the luminance coding tree node corresponding to the chrominance coding tree node is not partitioning, the horizontal ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes using one of the horizontal ternary division mode, a vertical binary splitting mode, a vertical ternary splitting mode, or a quadtree splitting mode, where each of a chroma coding tree node size, a luminance coding tree node size, and a luminance block size is T1×T1.

Condition 5: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the horizontal ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is split into child nodes using one of the vertical binary splitting mode, a vertical ternary division mode; or a horizontal ternary division mode, where the luma coding tree node size is T1×T1 and the chrominance coding tree node size is T1×(T1/2).

Condition 6: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the vertical ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the horizontal binary splitting mode, a horizontal ternary splitting mode; or a quadtree splitting mode, where both the chroma coding tree node size and the luma coding tree node size are T1×T1.

Condition 7: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the ISP vertical prediction mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the vertical ternary splitting mode , a horizontal binary split mode, a horizontal triple split mode, or a quadtree split mode, where each of the chroma coding tree node size, the luminance coding tree node size, and the luma block size is each T1×T1.

Condition 8: The splitting mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the vertical ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes using one of the horizontal binary splitting mode, a horizontal ternary partitioning mode; or a vertical ternary partitioning mode, where the luminance coding tree node size and the luma block size are T1×T1, and the chroma coding tree node size is T1×(T1/2).

Condition 9: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the horizontal binary partitioning mode, where the size of the luma coding tree node is T1×T1.

Condition 10: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the vertical binary splitting mode, where the luminance coding tree node size is T1×T1.

Condition 11: The luminance coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the horizontal ternary partitioning mode, where the luminance coding tree node size is T1×T1.

Condition 12: The luma coding tree node corresponding to the chrominance coding tree node is divided into child nodes using the vertical ternary splitting mode, where the luminance coding tree node size is T1×T1.

Condition 13: The split mode used for the luminance coding tree node corresponding to the chrominance coding tree node is a split mode other than split mode and quadtree split mode, where the luma coding tree node size is T1×T1.

It should be noted that the split mode used for the luma coding tree node is a split mode other than split mode, and quadtree split means that the split mode used for luma coding tree node is not quad split mode or no split mode.

It should be noted here that in the multi-type quad-tree (quad-tree plus multi-type tree, QT-MTT) structure, the split modes allowed for a node include maximum no split mode, horizontal binary split mode, vertical binary split mode, a horizontal ternary split mode, a vertical ternary split mode, and a quadtree split mode; thus, that "the chroma coding tree node is partitioned into child nodes using one of vertical binary partitioning mode, vertical ternary partitioning mode, or quadtree partitioning mode" in condition 3 can be equivalently described in the QT-MTT structure as "mode The split mode used for the chrominance coding tree node is not a horizontal binary split mode, a horizontal ternary split mode, or a no split mode."

In an exemplary embodiment, based on the premise that the split mode used for the luma coding tree node corresponding to the chrominance coding tree node is limited to no split and quadtree split, the third predetermined condition includes at least one of conditions 1-9.

It should be noted here that the fact that a chroma coding tree node is divided into child nodes specifically means that a chroma coding tree node is divided into child nodes using one of a horizontal binary splitting mode, a vertical binary splitting mode, a horizontal ternary splitting mode, vertical ternary splitting mode; and quadtree splitting mode.

Optionally, the third predetermined condition includes:

The division mode of the luminance coding tree node corresponding to the chrominance coding tree node is not division, and the ISP prediction mode is used for the luma block of the luminance coding tree node, where the size of the luminance coding tree node is T1×T1.

Optionally, the third predetermined condition includes:

The splitting mode of the luma coding tree node corresponding to the chroma coding tree node is not split, the ISP mode is used for the luma block of the luma coding tree node, and the chroma coding tree node is split into child nodes, where each of the chrominance coding tree node size, the tree node size luminance coding and luminance block size is T1×T1.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes; or the luma coding tree node splitting mode is one of a horizontal binary splitting mode and a vertical binary splitting mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1.

Optionally, the third predetermined condition includes one or more conditions 1-13.

Optionally, the third predetermined condition includes condition 1 or condition 13.

Optionally, the third predetermined condition includes condition 2 or condition 13.

Optionally, the third predetermined condition includes condition 3, condition 5, condition 6, condition 8, and condition 13.

Optionally, the third predetermined condition includes condition 4, condition 5, condition 7, condition 8, and condition 13.

Optionally, the third predetermined condition includes condition 4, condition 5, condition 7, condition 8, condition 9, condition 10, condition 11, and condition 12.

In an exemplary embodiment, T1 may be equal to 64. That is, if the chroma coding tree node size is T1xT1, the chroma coding tree node size is effectively 64x64. If the chroma coding tree node size is T1×(T1/2), the chroma coding tree node size is actually 64×32. If the luminance coding tree node size is T1xT1, the luminance coding tree node size is actually 64x64. If the luminance block size of a luma coding tree node is T1xT1, the chroma coding tree node size is actually 64x64.

In an exemplary embodiment, after it is determined, based on the size and partitioning mode of the chroma coding tree node, whether to allow CCLM execution on the chroma coding unit included in the chroma coding tree node, it is determined whether the chroma coding unit satisfies the third predetermined condition to further determine whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node.

S603. Get the chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit.

The chroma coding unit prediction mode includes at least one of direct mode, planar mode, DC mode, angular mode, CCLM mode, pulse-code modulation (pulse-code modulation, PCM) and intra-block copy (IBC) mode.

In particular, the CuPredMode syntax element of the chrominance coding unit is parsed based on the syntax table. If the CuPredMode value of the chrominance coding unit is MODE_INTRA, pcm_flag is obtained by parsing where pcm_flag is used to indicate whether the PCM mode for the chrominance coding unit is used. If it is determined based on the pcm_flag that the PCM mode is not used for the chroma coding unit, the intra_chroma_pred_mode syntax element is additionally parsed.

If the CCLM mode is not enabled for the chroma coding unit, the chroma coding unit prediction mode may be determined based on Table 1 with the intra_chroma_pred_mode syntax element and the intraPredModeY luminance prediction mode corresponding to the chroma coding unit.

Table 1

intra_chroma_pred_mode[xCb][yCb] IntraredModeY[xCb + cbWidth/2][yCb + cbHeight/2] 0 50 18 1 X(0 ≤ X ≤ 66) 0 66 0 0 0 0 1 50 66 50 50 50 2 18 18 66 18 18 3 1 1 1 66 1 4 0 50 18 1 X

If the CCLM mode is enabled for the chroma coding unit, the chroma coding unit prediction mode can be determined based on Table 2 using the intra_chroma_pred_mode syntax element and the intraPredModeY luminance prediction mode corresponding to the chroma coding unit.

table 2

intra_chroma_pred_mode[xCb][yCb] IntraredModeY[xCb + cbWidth/2][yCb + cbHeight/2] 0 50 18 1 X(0 ≤ X ≤ 66) 0 66 0 0 0 0 1 50 66 50 50 50 2 18 18 66 18 18 3 1 1 1 66 1 4 81 81 81 81 81 5 82 82 82 82 82 6 83 83 83 83 83 7 0 50 18 1 X

xCb and xCr are the coordinates (which are expressed using the number of corresponding luminance samples) of the upper left corner of the chroma coding unit, cbWidth and cbHeight are respectively the width and height (which are expressed using the number of corresponding luminance samples) of the chroma coding unit, intra_chroma_pred_mode[ xCb][yCb] is the chroma coding block internal prediction mode number, IntraPredModeY[xCb + cbWidth/2][yCb + cbHeight/2] is the coordinate position intraprediction luminance mode (xCb + cbWidth/2, yCb + cbHeight/2 ) and intraprediction luminance mode IntraPredModeC[xCb][yCb] chroma coding units can be obtained by looking at Table 1 or Table 2.

S604. Performing intra prediction for a chroma coding unit based on a chroma coding unit prediction mode to obtain chroma coding unit prediction samples.

In an exemplary embodiment, the first identifier qtbtt_dual_tree_intra_flag and the second identifier sps_cclm_enabled_flag are parsed from the bitstream. The first identifier is used to indicate whether a split tree structure is used for the intra picture, and the second identifier is used to indicate whether to allow CCLM to be performed on a chrominance block in the video sequence. For example, if the value of the first identifier is equal to the first value (eg, 1 or "true"), the first identifier is used to indicate that the split tree structure is used for an internal picture in the video sequence; or, if the value of the first identifier is equal to the second value (eg, 0 or "false"), the first identifier is used to indicate that no split tree structure is used for the inner picture in the video sequence. If the value of the second identifier is equal to the first value (eg, 1 or "true"), the second identifier is used to indicate that CCLM is allowed to be performed on a chrominance block in the video sequence; or, if the value of the second identifier is equal to the second value (eg, 0 or "false"), the second identifier is used to indicate that CCLM is not allowed to be performed on a chrominance block in the video sequence.

When both the value of the first identifier and the value of the second identifier are equal to the first value, an intra prediction operation is performed on a chrominance coding unit using the intra prediction method of the present invention.

It is understood that in the decision in this embodiment of the present invention, based on the size and split mode of the chroma coding tree node, it is determined whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node, and thus the processing delay for performing CCLM on a chroma coding unit, and the throughput of the hardware decoder is increased.

Fig. 7 is a flowchart of a decoding method according to an embodiment of the present invention. As shown in Fig.7, the method includes the following steps.

S701. Parse the bitstream in order to obtain the size and splitting mode of a chroma coding tree node.

Specifically, the video decoding unit decodes the bitstream to obtain the corresponding syntax element, and further determines the size and split mode of the chroma coding tree node based on the syntax element.

S702. Determine, based on the size and partitioning mode of the chroma coding tree node, whether to allow inter-component linear model (CCLM) intra prediction to be performed on the chroma coding unit included in the chroma coding tree node.

S703. Determine the chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit.

S704. Process the chroma coding unit based on the chroma coding unit prediction mode to obtain chroma coding unit prediction samples.

Note that, for specific descriptions of steps S701 to S704, refer to the respective descriptions of steps S601 to S604 in the embodiment shown in FIG. The details are not described again in this document.

S705. Obtain the recovered chroma coding unit residuals, and obtain the recovered chroma coding unit samples based on the recovered chroma coding unit residuals and the chroma coding unit prediction samples.

Specifically, the residual information includes a coded block flag and a transform factor, and may further include a horizontal transform type and a vertical transform type (eg, DCT-2, DCT-7, or DCT-8).

In particular, the bit stream is parsed. If chroma coding unit residual information is obtained through parsing, dequantization processing and inverse transformation processing are performed on the chroma coding unit residual information to obtain recovered chrominance coding unit residuals; or, if the chroma coding unit residual information is not obtained by parsing, it is determined that the recovered chroma coding unit residuals are 0. The residual information includes a coded block flag and a transform factor, and may further include a horizontal transform type and a type vertical conversion (for example, DCT-2, DCT-7 or DCT-8). To obtain recovered chroma coding unit samples, recovered chroma coding unit residuals and chroma coding unit prediction samples are added, and the addition results are discarded so as to be within a predetermined range of values (eg, 0 to 255 or 0 to 1023).

It is understood that, in the decision in this embodiment of the present invention, it is determined, based on the size and split mode of the chroma coding tree node, whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node, and thus the processing delay is reduced. to perform CCLM on a chroma coding unit, the throughput of the hardware decoder is increased and the video decoding efficiency is improved.

FIG. 8 is a schematic structural diagram of an intra prediction apparatus according to an embodiment of the present invention. As shown in FIG. 8, the intra predictor 800 includes:

an acquisition unit 801, configured to obtain a size and split mode of a chroma coding tree node;

a determination unit 802, configured to: determine, based on the size and split mode of the chroma coding tree node, whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node; and determining a chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit; And

a predictor 803, configured to process a chroma coding unit based on a chroma coding unit prediction mode to obtain chroma coding unit prediction samples.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and splitting mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node, the block 802 definitions are specifically designed to:

when M and N are equal to a predetermined threshold T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and splitting mode of the chroma coding tree node, as to whether to allow CCLM to be performed on a chroma coding unit included in the chroma coding tree node, the block 802 definitions are specifically designed to:

when M is T1 and N is T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an exemplary embodiment, in terms of determining, based on the size and partitioning mode of a chroma coding tree node, as to whether to allow intra-component linear model (CCLM) prediction to be performed on a chroma coding unit included in a chroma coding tree node, determine block 802 specially designed for:

determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode for the corresponding luma block when the luminance coding tree node is not split, regardless of whether whether CCLM is allowed to be performed on the chroma coding unit included in the chroma coding tree node.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode for the corresponding luminance block, when the luminance coding tree node is not split, and whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node, the determining block 802 is specifically configured to:

when the division mode of the chroma coding tree node satisfies the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or

when the division mode of the chroma coding tree node does not satisfy the third predetermined condition, M is T1, and N is T1, if the division mode of the chroma coding tree node satisfies the first predetermined condition, determining to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the first predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the first predetermined condition includes non-split mode or quadtree split mode.

In an exemplary embodiment, the size of a chroma coding tree node is M×N, and in the aspect of determining, based on the size and split mode of the chroma coding tree node, the split mode of the luma coding tree node corresponding to the chroma coding tree node, and whether to allow the use of the ISP mode for the corresponding luminance block, when the luminance coding tree node is not divided, whether to allow CCLM execution on the chroma coding unit included in the chroma coding tree node, the determination block 802 is specifically configured to:

when the division mode of the chroma coding tree node satisfies any one condition in the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the split mode of the chroma coding tree node does not meet the third predetermined condition, N=T1 and M=T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining to allow execution of CCLM on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition includes non-split mode or vertical binary split mode.

In an exemplary embodiment, the third predetermined condition includes one or more of: condition 1, condition 2, condition 3, condition 4, condition 5, condition 6, condition 7, condition 8, condition 9, condition 10, condition 11, condition 12 and conditions 13 in the example shown in FIG.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the ISP prediction mode is used for the luminance block of the luminance coding tree node, where the luminance coding tree node size and the luma block size are T1×T1.

Optionally, the third predetermined condition includes:

The division mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes, where each of the chroma coding tree node size, the tree node size luminance coding and luminance block size is T1×T1.

In an exemplary embodiment, the third predetermined condition includes condition 1 and condition 13 in the example shown in FIG.

Optionally, the third predetermined condition includes condition 2 and condition 13 in the example shown in FIG.

the division mode of the luma coding tree node corresponding to the chrominance coding tree node is not a division, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is divided into child nodes; or the luma coding tree node split mode is one of a horizontal binary split mode and a vertical binary split mode, where each of the chroma coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1.

Optionally, the third predetermined condition includes:

The division mode of the luminance coding tree node corresponding to the chrominance coding tree node is one of the following modes: no division mode, quadtree division mode, horizontal binary division mode, and vertical binary division mode, where the luminance coding tree node size is T1×T1; or

Optionally, the third predetermined condition includes condition 3, condition 5, condition 6, condition 8, and condition 13 in the example shown in FIG.

In an exemplary embodiment, the third predetermined condition includes condition 4, condition 5, condition 7, condition 8, and condition 13 in the example shown in FIG.

In an exemplary embodiment, the third predetermined condition includes condition 3, condition 5, condition 7, condition 8, condition 9, condition 10, condition 11, and condition 12 in the example shown in FIG.

In an exemplary embodiment, the predetermined threshold T1 is 64.

It should be noted that the above blocks (obtaining block 801, determining block 802, and prediction block 803) are configured to perform the associated steps of the above methods. Specifically, the acquisition unit 801 is configured to execute content associated with it in steps S601 and S701, the determine unit 802 is configured to execute content associated therewith in steps S602, S603, S702, and S703, and the prediction unit 803 is configured to execute associated content. content with him in steps S604 and S704. In other words, the acquisition unit 801 is configured to implement its associated functions of the entropy decoder 303 and the internal predictor 309 shown in FIG. fig.5b.

In this embodiment, the intra predictor 800 is represented as a block. A "unit" as used herein may be an application-specific integrated circuit (ASIC), a processor and memory that executes one or more programs or firmware, an integrated logic circuit, and/or other device that enables the aforementioned functions to be performed.

Fig. 9 is a schematic block diagram of an intra prediction device for a video sequence according to an embodiment of the present invention. As shown in FIG. 9, the intra predictor 900 includes:

a decoding unit 901, configured to parse the bitstream to obtain a first identifier and a second identifier, where the first identifier is used to indicate whether a split tree structure is used for an internal picture in the video sequence, and the second identifier is used to indicate whether to allow execution of CCLM above the color block in the video sequence; And

a predictor 902 configured: if the first identifier indicates that a split tree structure is used for an intra picture in the video sequence, and the second identifier indicates that CCLM can be performed on a chrominance block in the video sequence, performing part or all of the steps of the intra prediction method for the video sequence, shown in Fig.6.

It should be noted that the above blocks (decoding block 901 and prediction block 903) are configured to perform the associated steps of the above method. In other words, the decoder 901 is configured to implement the associated functions of the entropy decoder 303 shown in FIG. 5b, and the predictor 902 is configured to implement the associated functions of the internal predictor 309 shown in FIG. 5b.

Embodiments of the present invention further provide a computer storage medium. The computer storage medium may store the program, wherein execution of the program performs at least a portion or all of the steps of any of the intra prediction methods described in the above method embodiments.

One of skill in the art will appreciate that the functions described with reference to the various illustrative logical blocks, modules, and algorithm steps disclosed and described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions described with reference to illustrative logical blocks, modules, and steps may be stored or transmitted on a computer-readable storage medium as one or more instructions or code and executed by a hardware processing unit. A computer-readable medium may include a computer-readable medium that corresponds to a tangible medium, such as a storage medium, or may include any transmission medium that enables the transfer of a computer program from one place to another (eg, according to a communication protocol). Thus, a computer readable medium may generally correspond to: (1) a non-transitory tangible computer readable medium, or (2) a transmission medium such as a signal or a carrier wave. A storage medium can be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and/or data structures for implementing the technologies described herein. The computer program product may include a computer-readable storage medium.

By way of example, and not limitation, such computer-readable storage media may include RAM, RAM, EEPROM, CD-ROM or other compact disk storage device, magnetic disk storage device or other magnetic storage device, flash memory, or any another storage medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer. In addition to this, any connection is essentially referred to as a computer-readable storage medium. For example, if an instruction is transmitted from a website, server, or other remote source using coaxial cable, optical fiber, twisted pair, digital subscriber line (DSL), or wireless technology using, for example, electromagnetic waves in the infrared, radio, or microwave bands , then coaxial cable, optical fiber, twisted pair, DSL, or wireless technology using, for example, electromagnetic waves in the infrared, radio, or microwave ranges are included in the definition of media. However, it should be understood that computer-readable media and media do not include connections, carrier waves, signals, or other temporary media, but actually mean non-temporal and temporary media. The magnetic discs and optical discs used herein include a compact disc (CD), a laser disc, an optical disc, a digital versatile disc (DVD), and a Blu-ray disc. Magnetic discs usually reproduce data magnetically, while optical discs reproduce data optically using lasers. Combinations of the above means should also be included within the scope of computer readable media.

An instruction may be executed by one or more processors, such as one or more of: digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated circuits or discrete logic circuits. Thus, the term "processor" as used in this specification may mean any of the aforementioned structures, or any other structure suitable for implementing the technologies described in this specification. In addition, in some aspects, the functions described in terms of the illustrative logical blocks, modules, and steps described herein may be provided in dedicated hardware and/or software modules capable of encoding and decoding, or may be included in an integrated codec. In addition, all of these technologies can be implemented in one or more circuits or logic elements.

The technologies presented in this application may be implemented in various hardware devices or devices, including a wireless telephone, an integrated circuit (IC), or an IC stack (eg, a chipset). The present application describes various components, modules, or blocks in order to highlight the functional aspects of devices capable of implementing the disclosed technologies, but not necessarily implemented in different hardware blocks. In fact, as described above, the various blocks may be combined into a codec hardware block in combination with appropriate software and/or firmware, or may be implemented with interoperable hardware blocks (including one or more of the processors described above).

The above descriptions are merely examples of specific implementations of the present application, but are not intended to limit the scope of protection of the present application. Any modification or substitution readily understood by a person skilled in the art within the technical scope disclosed in this application should fall within the protection scope of this application. Thus, the scope of protection of the present application should be consistent with the scope of protection of the claims.

Claims (49)

1. A video sequence intra prediction method in which a split tree structure is used for an intra image in a video sequence, comprising: obtaining a size and splitting mode of a chroma coding tree node; determining, based on the size and splitting mode of the chrominance coding tree node, as to whether to allow performing inter-component linear model (CCLM) intra prediction on a chroma coding unit included in the chrominance coding tree node; determining a chroma coding unit prediction mode depending on whether CCLM is allowed to be performed on the chroma coding unit; And processing a chroma coding unit based on a chroma coding unit prediction mode to obtain chroma coding unit prediction samples; wherein the size of the chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node, whether to allow intra-component linear model (CCLM) prediction to be performed on the chroma coding unit included in the tree node color coding, contains: when M is equal to a predetermined threshold T1 and N is equal to T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit, where the second predetermined condition does not contain a split mode or a vertical binary split mode. 2. The method of claim 1, wherein determining, based on the size and split mode of the chroma coding tree node, as to whether to allow intra-component linear model (CCLM) prediction to be performed on a chroma coding unit included in the chroma coding tree node comprises : determining, based on the size and split mode of the chrominance coding tree node and the split mode of the luminance coding tree node corresponding to the chroma coding tree node, as to whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node. 3. The method of claim 2, wherein the size of the chroma coding tree node is M×N, and determining, based on the size and split mode of the chroma coding tree node and the split mode of the luma coding tree node corresponding to the chroma coding tree node, whether to allow Whether performing CCLM on a chroma coding unit included in a chroma coding tree node contains: when the division mode of the chroma coding tree node satisfies the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the split mode of the chroma coding tree node does not satisfy the third predetermined condition, N=T1 and M=T1/2, if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit. 4. The method of claim 3, wherein the third predetermined condition comprises: the division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the intra subsection (ISP) mode is used for the luminance block of the luminance coding tree node, where the size of the luminance coding tree node and the size of the luma block are T1×T1. 5. The method of claim 3, wherein the third predetermined condition comprises: the split mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is split into child nodes, where each of the chrominance coding tree node size, the tree node size luminance coding and luminance block size is T1×T1. 6. The method of claim 3, wherein the third predetermined condition comprises: the split mode used for the luminance coding tree node corresponding to the chrominance coding tree node is a split mode other than the split mode and the quadtree split mode, where the size of the luma coding tree node is T1×T1. 7. The method of claim 3, wherein the third predetermined condition comprises: the luminance coding tree node splitting mode is one of a horizontal binary splitting mode and a vertical binary splitting mode, where each of the chrominance coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1. 8. The method according to any one of claims 1 to 7, wherein the predetermined threshold T1 is 64. 9. A method for internal prediction of a video sequence, comprising: parsing the bitstream to obtain a first identifier and a second identifier, wherein the first identifier is used to indicate whether a split tree structure is used for an internal picture in the video sequence, and the second identifier is used to indicate whether to allow intra-component linear model (CCLM) prediction to be performed ) above the chrominance block in the video sequence; And if the first identifier indicates that the partition tree structure is used for an internal image in the video sequence, and the second identifier indicates that CCLM can be performed on a chrominance block in the video sequence, performing the method according to any one of claims 1 to 8. 10. An intra-predictor for a video sequence, comprising: an acquisition unit configured to obtain a size and split mode of a chroma coding tree node in which a split tree structure is used for an intra image in the video sequence; a determining unit, configured to: determine, based on the size and split mode of the chroma coding tree node, whether to allow intra-component linear model (CCLM) prediction to be performed on a chroma coding unit included in the chroma coding tree node; and determining a block chrominance prediction mode depending on whether CCLM is allowed to be performed on the chrominance coding unit; And a predictor configured to process a chroma coding unit based on a chroma coding unit prediction mode to obtain chroma coding unit prediction samples; wherein the size of the chroma coding tree node is M×N, and in the aspect of determining, based on the size and splitting mode of the chroma coding tree node, whether to allow intra-component linear model (CCLM) prediction to be performed on the chroma coding unit included in node of the chrominance coding tree, the determination block is specially configured to: when M is equal to a predetermined threshold T1 and N is equal to T1/2, if the division mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be performed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit in which the second predetermined condition does not contain a split mode or a vertical binary split mode. 11. The apparatus of claim 10, wherein, in the aspect of determining, based on the size and split mode of the chroma coding tree node, whether to allow intra-component linear model (CCLM) prediction to be performed on a chroma coding unit included in the coding tree node chromaticity, the determination block is specially made with the possibility of: determining, based on the size and split mode of the chrominance coding tree node and the split mode of the luma coding tree node corresponding to the chroma coding tree node, as to whether to allow CCLM to be performed on the chroma coding unit included in the chroma coding tree node. 12. The apparatus of claim 11, wherein the size of the chroma coding tree node is M×N, and in the aspect of determining, based on the size and split mode of the chroma coding tree node and the split mode of the luma coding tree node corresponding to the chroma coding tree node, relatively whether to allow CCLM to be performed on a chroma coding unit included in a chroma coding tree node, the determining unit is specifically configured to: when the division mode of the chroma coding tree node satisfies the third predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit; or when the split mode of the chroma coding tree node does not satisfy the third predetermined condition, N=T1, and M=T1/2 if the split mode of the chroma coding tree node satisfies the second predetermined condition, determining whether to allow CCLM to be executed on the chroma coding unit; or, if the split mode of the chroma coding tree node does not satisfy the second predetermined condition, determining not to allow CCLM to be performed on the chroma coding unit. 13. The apparatus of claim 12, wherein the third predetermined condition comprises: the division mode of the luma coding tree node corresponding to the chrominance coding tree node is not division, and the intra subsection (ISP) mode is used for the luminance block of the luminance coding tree node, where the size of the luminance coding tree node and the size of the luma block are T1×T1. 14. The apparatus of claim 12, wherein the third predetermined condition comprises: the split mode of the luma coding tree node corresponding to the chrominance coding tree node is not split, the ISP mode is used for the luma block of the luminance coding tree node, and the chroma coding tree node is split into child nodes, where each of the chrominance coding tree node size, the tree node size luminance coding and luma block size is T1xT1. 15. The apparatus of claim 12, wherein the third predetermined condition comprises: the split mode used for the luminance coding tree node corresponding to the chrominance coding tree node is a split mode other than the split mode and the quadtree split mode, where the size of the luma coding tree node is T1×T1. 16. The apparatus of claim 12, wherein the third predetermined condition comprises: the luminance coding tree node splitting mode is one of a horizontal binary splitting mode and a vertical binary splitting mode, where each of the chrominance coding tree node size, the luma coding tree node size, and the luminance block size is T1×T1. 17. The device according to any one of paragraphs. 10-16, in which the predetermined threshold T1 is 64. 18. An internal video sequence prediction device, comprising: a decoding unit configured to parse the bitstream to obtain a first identifier and a second identifier, the first identifier being used to indicate whether a split tree structure is used for an intra picture in the video sequence, and the second identifier being used to indicate whether intra prediction is allowed to be performed by a cross-component linear model (CCLM) over a chrominance block in a video sequence; And a prediction block configured: if the first identifier indicates that the split tree structure is used for an internal image in the video sequence, and the second identifier indicates that CCLM can be performed on a chrominance block in the video sequence, performing the method according to any one of claims 1 to 8.

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