CN-115176474-B - Cross-component prediction for multi-parameter models

Abstract

A video processing method includes performing a conversion between a current video block of a second color component of video and a bitstream of the video using cross-component prediction (CCPMPM) with a multi-parameter model, wherein samples of the current video block are predicted in the bitstream using linear combinations of samples of the first color component multiplied by linear coefficients and/or one or more offsets. The bit stream complies with the format rules. The linear coefficients of CCPMPM are determined using a first rule. A sampling point of the first color component is determined using a second rule.

Inventors

• LIU HONGBIN
• ZHANG LI
• ZHANG KAI
• XU JIZHENG
• HE YUWEN
• WANG YUE

Assignees

• 抖音视界有限公司
• 抖音视界有限公司
• 字节跳动有限公司
• 字节跳动有限公司

Dates

Publication Date

20260421

Application Date

20201231

Priority Date

20191231

Claims (20)

1. 1. A video processing method, comprising: Performing a conversion between a current video block of a second color component of a video and a bitstream of the video using cross-component prediction CCPMPM having a multi-parameter model, wherein in the CCPMPM, samples of the current video block are predicted to be encoded in the bitstream using a linear combination of samples of the first color component multiplied by linear coefficients and one or more offsets; wherein the bit stream complies with a format rule, and Wherein the linear coefficients of the CCPMPM are determined using a first rule; Wherein a second rule is used to determine a sampling point of the first color component; Wherein each set of samples in the plurality of sets of samples of the first color component is defined by a filter shape and a center sample of each set of samples, and classifying the samples of the first color component into sets by a classification method according to the filter shape and the center samples of each set of samples and/or the center of the filter shape.
2. 2. The method of claim 1, wherein the samples of the first color component comprise a plurality of sets of samples of the first color component, wherein one of the linear coefficients is applied to each sample in the set of samples of the first color component.
3. 3. The method of claim 2, wherein the one or more offsets comprise an offset applied to the linear combination of each set of samples of the first color component.
4. 4. The method of claim 1, wherein the center sample depends on a color format of the video and/or a predicted location of a sample of the second color component, wherein the color format is 4:4:4, 4:2:2, or 4:2:0.
5. 5. The method of claim 4, wherein if the samples of the second color component are located at (x, y), then in the case of a 4:4:4 format, the center samples are located at positions (x, y) in the first color component, wherein x and y represent decimal or integer sample point numbers.
6. 6. The method according to claim 4, wherein if the samples of the second color component are located at (x, y), then in case of a 4:2:2 format the center samples are located at positions (2 X, y), where x and y represent decimal or integer sample point numbers.
7. 7. The method according to claim 4, wherein if the samples of the second color component are located at (x, y), then in case of a 4:2:0 format the center samples are located at positions (2 x, 2 Y), wherein x and y represent decimal or integer sample point numbers.
8. 8. The method of claim 4, wherein the filter shape is one of an N1-point rectangle or an N3-point square, an N2-point diamond, an N4-point hexagon, or an N5-point octagon, wherein N1, N2, N3, N4, and N5 are positive integers.
9. 9. The method of claim 8, wherein the filter shape of the current video block depends on an intra prediction mode used to codec the current video block.
10. 10. The method of claim 4, wherein the first rule and the second rule specify that identically shaped samples are used for linear prediction and deriving the linear coefficients and/or the one or more offsets.
11. 11. The method of claim 10, wherein the first rule specifies deriving the linear coefficients and/or the one or more offsets using least squares and calculation operations.
12. 12. The method of claim 1, wherein the classifying method comprises classifying the samples of the first color component into groups according to symmetry about a vertical line containing a center of the filter shape.
13. 13. The method of claim 12, wherein the classifying method further comprises classifying the samples located on the vertical line as a group.
14. 14. The method of claim 12, wherein the classifying method further comprises classifying the samples located on the vertical line and the samples symmetric about the center of the filter shape into a set.
15. 15. The method of claim 1, wherein the classifying method comprises classifying the samples of the first color component into groups according to symmetry about a horizontal line containing a center of the filter shape.
16. 16. The method of claim 15, wherein the classifying method further comprises classifying the samples located on the horizontal line as a group.
17. 17. The method of claim 15, wherein the classifying method further comprises classifying the samples located on the horizontal line and the centrosymmetric samples with respect to the filter shape into a set.
18. 18. The method of claim 1, wherein the classifying method comprises classifying the samples of the first color component into groups according to symmetry about a center of the filter shape.
19. 19. The method of claim 1, wherein the classifying method comprises classifying samples of the first color component that lie on a horizontal line containing a center of the filter shape into groups.
20. 20. The method of claim 1, wherein the classifying method comprises classifying samples of the first color component that lie on a vertical line containing a center of the filter shape into groups.

Description

Cross-component prediction for multi-parameter models Cross Reference to Related Applications The present application timely claims the priority and benefit of international patent application PCT/CN2019/130430 filed on 12/31 of 2019, in accordance with applicable patent laws and/or regulations of paris convention. The entire disclosure of the above application is incorporated by reference as part of the present disclosure for all purposes in accordance with law. Technical Field This patent document relates to video codec and decoding techniques, devices, and systems. Background Currently, efforts are underway to improve the performance of current video codec technology to provide better compression ratios or to provide video codec and decoding schemes that allow for lower complexity or parallelized implementations. Industry professionals have recently proposed several new video codec tools that are currently being tested to determine their effectiveness. Disclosure of Invention Devices, systems and methods related to digital video coding and decoding, and in particular to management of motion vectors, are described. The described methods may be applied to existing Video codec standards (e.g., HIGH EFFICIENCY Video Coding (HEVC) and/or multi-function Video codec) and future Video codec standards or Video codecs. In one representative aspect, a video processing method is disclosed. The method includes performing a transition between a current video block of the video and a bitstream of the video using an intra-prediction codec in which the prediction is performed using one or more reference lines selectively according to a rule, wherein the bitstream conforms to a format rule, wherein the current video block has a color component different from a luminance color component of the video. In another representative aspect, a video processing method is disclosed. The method includes, for a transition between a current video block of a color component of a video and a bitstream of the video, determining that the current video block inherits intra-coding characteristics from a corresponding intra-coding luma video block, and performing the transition based on the determination. In another representative aspect, a video processing method is disclosed. The method comprises performing a conversion between a current video block of a second color component of a video and a bitstream of the video using cross-component prediction (cross-component prediction with multiple-PARAMETER MODEL, CCPMPM) with a multi-parameter model, wherein samples of the current video block are predicted in the bitstream using linear combinations of samples of a first color component multiplied by linear coefficients and/or one or more offsets, wherein the bitstream complies with a format rule, and wherein the linear coefficients of the CCPMPM are determined using a first rule, and wherein samples of the first color component are determined using a second rule. In another representative aspect, a video processing method is disclosed. The method includes determining, for a transition between a current video block of a first component of a video and a bitstream of the video, a prediction using the current video block from a linear combination of samples of a second video block of a second component of the video according to a rule, and performing the transition based on the determination, wherein the current video block and the second video block are encoded using a local illumination compensation tool. In another representative aspect, a video processing method is disclosed. The method comprises performing a transition between a current video block of video and a bitstream of the video, wherein samples of the current video block are predictively encoded using a multi-parameter model (multiple-PARAMETER MODEL, IPMPM) in which linear combinations of reference samples of the video use linear coefficients and/or offset values, and wherein the bitstream complies with a format rule. Further, in one representative aspect, an apparatus in a video system is disclosed that includes a processor and a non-transitory memory having instructions thereon. The instructions, when executed by the processor, cause the processor to perform any one or more of the disclosed methods. In another aspect, a bitstream stored on a computer readable storage medium is disclosed, wherein the bitstream is generated according to the encoding method described in this document. Furthermore, a computer program product stored on a non-transitory computer readable medium is disclosed, the computer program product comprising program code to perform any one or more of the disclosed methods. The above and other aspects and features of the disclosed technology are described in more detail in the accompanying drawings, description and claims. Drawings Fig. 1 shows an example block diagram of an encoder. Fig. 2 shows an example of 67 intra prediction modes Fig. 3 shows a schematic diagram o