Intra-prediction using a cross-component linear model in video coding

Patent metadata

Field	Value
Publication number	US-11528506-B2
Application number	US-202117146955-A
Country	US
Kind code	B2
Filing date	Jan 12, 2021
Priority date	Jul 12, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A video coding mechanism is disclosed. The mechanism includes receiving a video signal partitioned into a chroma block and a first neighboring luma block. The mechanism also includes encoding prediction information for chroma samples of the chroma block into a bitstream. The prediction information for the chroma samples is determined via intra-prediction based on down-sampled neighboring luma samples. The down-sampled neighboring luma samples are generated from a single row of luma samples from the first neighboring luma block. A bitstream including the prediction information for the chroma samples is transmitted to support decoding and display of the chroma samples.

First claim

What is claimed is:

1. A method for cross-component prediction of a block of video data, the method comprising:
down-sampling a reconstructed luma block to obtain a down-sampled luma block, the reconstructed luma block corresponding to a chroma block;
determining a max luma value and a min luma value based on first down-sampled samples of reconstructed top neighboring luma samples that are above the reconstructed luma block or second down-sampled samples of reconstructed left neighboring luma samples within a single column that is left of the reconstructed luma block, wherein the reconstructed top neighboring luma samples are within a single row being adjacent to the reconstructed luma block;
determining a first chroma value and a second chroma value based on reconstructed neighboring chroma samples of the chroma block, wherein the first chroma value and the second chroma value are respectively associated with the max luma value and the min luma value;
deriving, parameters of a linear model (LM) based on the max luma value, the min luma value, the first chroma value, and the second chroma value; and
generating predicted chroma values of the chroma block based on the parameters of the LM and the down-sampled luma block.

2. The method of claim 1 , wherein the max luma value is determined based on values of one or more first down-sampled samples that are larger than values of remaining first down-sampled samples.

3. The method of claim 1 , wherein the min luma value is obtained based on values of one or more first down-sampled samples that are smaller than values of remaining first down-sampled samples.

4. The method of claim 1 , wherein the max luma value is determined based on values of one or more second down-sampled samples that are larger than values of remaining second down-sampled samples.

5. The method of claim 1 , wherein the min luma value is obtained based on values of one or more first down-sampled samples that are smaller than values of a rest of the first down-sampled samples.

6. The method of claim 1 , wherein the first chroma value is determined based on values of one or more reconstructed neighboring chroma samples, wherein the one or more reconstructed neighboring chroma samples corresponds to one or more of the first down-sampled samples whose values are larger than values of remaining first down-sampled samples, and the second chroma value is determined based on values of one or more reconstructed neighboring chroma samples, wherein the one or more reconstructed neighboring chroma samples correspond to one or more of the first down-sampled samples whose values are smaller than values of the remaining first down-sampled samples.

7. The method of claim 1 , wherein the first chroma value is determined based on values of one or more reconstructed neighboring chroma samples, wherein the one or more reconstructed neighboring chroma samples corresponds to one or more of the second down-sampled samples whose values are larger than values of remaining second down-sampled samples, and the second chroma value is determined based on values of one or more reconstructed neighboring chroma samples, wherein the one or more reconstructed neighboring chroma samples correspond to one or more of the second down-sampled samples whose values are smaller than values of the remaining second down-sampled samples.

8. The method of claim 1 , wherein the determining a first chroma value and a second chroma value based on reconstructed neighboring chroma samples of the chroma block, comprises:
determining, from the reconstructed neighboring chroma samples of the chroma block, a first chroma value and a second chroma value respectively corresponding to the max luma value and the min luma value.

9. The method of claim 1 , wherein the first down-sampled samples are obtained by down-sampling the reconstructed top neighboring luma samples which are within the single row being adjacent to the reconstructed luma block.

10. The method of claim 1 , wherein the second down-sampled samples are obtained by down-sampling on the reconstructed left neighboring luma samples.

11. The method of claim 1 , wherein the reconstructed left neighboring luma samples are within N columns which are left of the reconstructed luma block, wherein 0<N<=3 and N is a positive integer.

12. The method of claim 1 , wherein the LM comprises one or more of a cross-component linear model (CCLM) mode, a multi-directional linear model (MDLM) mode, and a multiple model linear model (MMLM) mode.

13. A method for cross-component prediction of a block of video data, the method comprising:
down-sampling a reconstructed luma block to obtain a down-sampled luma block, the reconstructed luma block corresponding to a chroma block;
determining a max luma value and a min luma value based on first down-sampled samples of reconstructed top neighboring luma samples that are above the reconstructed luma block or second down-sampled samples of reconstructed left neighboring luma samples within N columns which are left of the reconstructed luma block, wherein 0<N<=3 and N is a positive integer, and wherein the reconstructed top neighboring luma samples are within a single row being adjacent to the reconstructed luma block;
determining a first chroma value and a second chroma value based on reconstructed neighboring chroma samples of the chroma block, wherein the first chroma value and the second chroma value are respectively associated with the max luma value and the min luma value;
deriving, parameters of a linear model (LM) based on the max luma value, the min luma value, the first chroma value, and the second chroma value; and
generating predicted chroma values of the chroma block based on the parameters of the LM and the down-sampled luma block.

14. The method of claim 13 , wherein the max luma value is determined based on values of one or more first down-sampled samples that are larger than values of remaining first down-sampled samples.

15. The method of claim 13 , wherein the min luma value is obtained based on values of one or more first down-sampled samples that are smaller than values of remaining first down-sampled samples.

16. The method of claim 13 , wherein the max luma value is determined based on values of one or more second down-sampled samples that are larger than values of remaining second down- sampled samples.

17. The method of claim 13 , wherein the min luma value is obtained based on values of one or more first down-sampled samples that are smaller than values of a rest of the first down-sampled samples.

18. A video coding device configured to perform cross-component prediction of a block of video data, the video coding device comprising a processor configured to:
down-sample a reconstructed luma block to obtain a down-sampled luma block, the reconstructed luma block corresponding to a chroma block;
determine a max luma value and a min luma value based on first down-sampled samples of reconstructed top neighboring luma samples that are above the reconstructed luma block or second down-sampled samples of reconstructed left neighboring luma samples within N columns which are left of the reconstructed luma block, wherein 0<N<=3 and N is a positive integer, wherein the reconstructed top neighboring luma samples are within a single row being adjacent to the reconstructed luma block;
determine a first chroma value and a second chroma value based on reconstructed neighboring chroma samples of the chroma block, wherein the first chroma value and the second chroma value are respectively associated with the max l

Assignees

• Huawei Tech Co Ltd

Inventors

• Ma Xiang
• Chen Jianle
• Yang Haitao

Classifications

• H04N19/186 Primary

  the unit being a colour or a chrominance component · CPC title

• H04N19/132

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/59

  involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution · CPC title

• H04N19/11

  among a plurality of spatial predictive coding modes · CPC title