Multi-parameters based intra prediction

Patent metadata

Field	Value
Publication number	US-12184865-B2
Application number	US-202318310344-A
Country	US
Kind code	B2
Filing date	May 1, 2023
Priority date	Nov 6, 2018
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A method for video processing is provided. The method includes determining, for a conversion between a current video block of a video that is a chroma block and a coded representation of the video, multiple sets of parameters, wherein each set of parameters defines a cross-component linear model (CCLM) and is derived from a corresponding group of chroma samples at corresponding chroma sample positions; determining, based on the multiple sets of parameters, parameters for a final CCLM; and performing the conversion based on the final CCLM.

First claim

What is claimed is:

1. A method of video processing, comprising:
determining, for a conversion between a current video block of a video that is a chroma block and a bitstream of the video, values of parameters of a cross-component linear model (CCLM) in a CCLM mode based on two chroma values denoted as minC and maxC and two luma values denoted as minY and maxY;
deriving, using the CCLM, predicted samples of the current video block based on reconstructed samples of a luma block corresponding to the current video block and the parameters of the CCLM; and
performing the conversion based on the predicted samples of the current video block,
wherein when maxY is not equal to minY, then one of the parameters is further determined based on a look-up table using an index derived based on a difference between maxY and minY, wherein when maxY is equal to minY, then the predicted samples of the current video block are based on minC and not based on minY, maxY and maxC,
wherein the max Y, the maxC, the minY, and the minC are derived from two or four indices, wherein an index is mapped with a chroma sample and a corresponding luma sample, and wherein in response to two chroma samples and two corresponding luma samples mapped with two original indices being used to derive the maxY, the maxC, the minY and the minC, applying a padding operation to generate two padded chroma samples and two padded luma samples, and
wherein the two original indices are denoted as S0 and S1, and two mapped indices with which the two padded chroma samples and the two padded luma samples are mapped are denoted as S2 and S3, and wherein the padding operation is done as follows orderly:
1) The chroma sample and the corresponding luma sample mapped with S0 is copied to the chroma sample and the corresponding luma sample mapped with S3, respectively;
2) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S2, respectively;
3) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S0, respectively; and
4) The chroma sample and the corresponding luma sample mapped with S3 is copied to the chroma sample and the corresponding luma sample mapped with S1, respectively.

2. The method of claim 1 , wherein the conversion includes encoding the current video block into the bitstream.

3. The method of claim 1 , wherein the conversion includes decoding the current video block from the bitstream.

4. An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:
determine, for a conversion between a current video block of a video that is a chroma block and a bitstream of the video, values of parameters of a cross-component linear model (CCLM) in a CCLM mode based on two chroma values denoted as minC and maxC and two luma values denoted as minY and maxY;
deriving, using the CCLM, predicted samples of the current video block based on reconstructed samples of a luma block corresponding to the current video block and the parameters of the CCLM; and
perform the conversion based on the predicted samples of the current video block,
wherein when maxY is not equal to minY, then one of the parameters is further determined based on a look-up table using an index derived based on a difference between maxY and minY,
wherein when maxY is equal to minY, then the predicted samples of the current video block are based on minC and not based on minY, maxY and maxC,
wherein the maxY, the maxC, the minY, and the minC are derived from two or four indices, wherein an index is mapped with a chroma sample and a corresponding luma sample, and wherein in response to two chroma samples and two corresponding luma samples mapped with two original indices being used to derive the maxY, the maxC, the minY and the minC, applying a padding operation to generate two padded chroma samples and two padded luma samples, and
wherein the two original indices are denoted as S0 and S1, and two mapped indices with which the two padded chroma samples and the two padded luma samples are mapped are denoted as S2 and S3, and wherein the padding operation is done as follows orderly:
1) The chroma sample and the corresponding luma sample mapped with S0 is copied to the chroma sample and the corresponding luma sample mapped with S3, respectively;
2) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S2, respectively;
3) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S0, respectively; and
4) The chroma sample and the corresponding luma sample mapped with S3 is copied to the chroma sample and the corresponding luma sample mapped with S1, respectively.

5. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:
determining, for a current video block of the video that is a chroma block, values of parameters of a cross-component linear model (CCLM) in a CCLM mode based on two chroma values denoted as minC and maxC and two luma values denoted as minY and maxY;
deriving, using the CCLM, predicted samples of the current video block based on reconstructed samples of a luma block corresponding to the current video block and the parameters of the CCLM; and
generating the bitstream based on the predicted samples of the current video block,
wherein when maxY is not equal to minY, then one of the parameters is further determined based on a look-up table using an index derived based on a difference between maxY and minY,
wherein when maxY is equal to minY, then the predicted samples of the current video block are based on minC and not based on minY, maxY and maxC,
wherein the maxY, the maxC, the minY, and the minC are derived from two or four indices, wherein an index is mapped with a chroma sample and a corresponding luma sample, and wherein in response to two chroma samples and two corresponding luma samples mapped with two original indices being used to derive the maxY, the maxC, the minY and the minC, applying a padding operation to generate two padded chroma samples and two padded luma samples,
wherein the two original indices are denoted as S0 and S1, and two mapped indices with which the two padded chroma samples and the two padded luma samples are mapped are denoted as S2 and S3, and wherein the padding operation is done as follows orderly:
1) The chroma sample and the corresponding luma sample mapped with S0 is copied to the chroma sample and the corresponding luma sample mapped with S3, respectively;
2) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S2, respectively;
3) The chroma sample and the corresponding luma sample mapped with S1 is copied to the chroma sample and the corresponding luma sample mapped with S0, respectively;
4) The chroma sample and the corresponding luma sample mapped with S3 is copied to the chroma sample and the corresponding luma sample mapped with S1, respectively.

6. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
determine, for a conversion between a current video block of a video that is a chroma block and a bitstream of the video, values of parameters of a cross-component linear model (CCLM) in a CCLM mode based on two chroma values denoted as minC and maxC and two luma values denot

Assignees

• Beijing Bytedance Network Tech Co Ltd
• Bytedance Inc

Inventors

• Zhang Kai
• Zhang Li
• Liu Hongbin
• Xu Jizheng
• Wang Yue

Classifications

• H04N19/463

  by compressing encoding parameters before transmission · CPC title

• H04N19/30 Primary

  using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence) · CPC title

• H04N19/105 Primary

  Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction · CPC title

• H04N19/157

  Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter · CPC title

• H04N19/156

  Availability of hardware or computational resources, e.g. encoding based on power-saving criteria · CPC title