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

Patent metadata

Field	Value
Publication number	US-12262053-B2
Application number	US-202318544099-A
Country	US
Kind code	B2
Filing date	Dec 18, 2023
Priority date	Jul 12, 2018
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

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 non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device 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, and 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 luma value and the min luma value;
derive 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
generate predicted chroma values of the chroma block based on the parameters of the LM and the down-sampled luma block,
wherein the second down-sampled luma samples are obtained by applying a six tap downsampling filter to the reconstructed left neighboring luma samples according to L[i]=(L2[2i]*2+L1[2i]+L3[2i]+L2[2i+1] *2+L1[2i+1]+L3[2i+1]+4)>>3, wherein L1[i], L2[i] and L3[i] are each an i-th reconstructed left neighboring luma sample in one of three columns adjacent to the reconstructed luma block, respectively, and L[i] is the i-th down-sampled luma sample of reconstructed left neighboring luma samples.

2. The non-transitory computer readable medium 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 non-transitory computer readable medium 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 non-transitory computer readable medium 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 non-transitory computer readable medium 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 non-transitory computer readable medium 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.

7. The non-transitory computer readable medium 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.

8. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device 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 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;
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 luma value and the min luma value;
derive 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
generate predicted chroma values of the chroma block based on the parameters of the LM and the down-sampled luma block,
wherein the second down-sampled luma samples are obtained by applying a six tap downsampling filter to the reconstructed left neighboring luma samples according to L[i]=(L2[2i]*2+L1[2i]+L3[2i]+L2[2i+1] *2+L1[2i+1]+L3[2i+1]+4)>>3, wherein L1[i], L2[i] and L3[i] are each an i-th reconstructed left neighboring luma sample in one of three columns adjacent to the reconstructed luma block, respectively, and L[i] is the i-th down-sampled luma sample of reconstructed left neighboring luma samples.

9. The non-transitory computer readable medium of claim 8 , 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.

10. The non-transitory computer readable medium of claim 8 , 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.

11. The non-transitory computer readable medium of claim 8 , 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.

12. The non-transitory computer readable medium of claim 8 , 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.

13. The non-transitory computer readable medium of claim 8 , 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.

14. The non-transitory computer readable medium of claim 8 , 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.

15. A 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 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;
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 luma value and the min luma value;
deriv

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

• H04N19/176

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

• H04N19/11

  among a plurality of spatial predictive coding modes · CPC title

• H04N19/59

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