# US 2023/0057680 A1 · Intra-Prediction Using a Cross-Component Linear Model in Video Coding

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- Number: US 2023/0057680 A1
- Document ID: US20230057680A1
- Status: Published application
- Kind: A1
- Application number: 17/979,532
- Filed: 2022-11-02
- Published: 2023-02-23
- Earliest claimed: 2018-07-12
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Xiang Ma; Jianle Chen; Haitao Yang
- Web page: https://patentgrep.com/patent/US20230057680A1

## CPC

- H04N 19/593: involving spatial prediction techniques
- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/59: involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## 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.

## Claims

### Claim 1

A non-transitory storage medium storing an encoded bitstream for video signals, the encoded bitstream comprises data for obtaining:
a reconstructed luma block down-sampled to obtain a down-sampled luma block, the reconstructed luma block corresponding to a chroma block;
a max luma value and a min luma value determined 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;
a first chroma value and a second chroma value determined 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;
parameters of a linear model (LM) derived based on the max luma value, the min luma value, the first chroma value, and the second chroma value; and
predicted chroma values of the chroma block generated based on the parameters of the LM and the down-sampled luma block.

### Claim 2 (depends on 1)

The non-transitory storage 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.

### Claim 3 (depends on 1)

The non-transitory storage 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.

### Claim 4 (depends on 1)

The non-transitory storage 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.

### Claim 5 (depends on 1)

The non-transitory storage 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.

### Claim 6 (depends on 1)

The non-transitory storage 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.

### Claim 7 (depends on 1)

The non-transitory storage 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.

### Claim 8

An encoder comprising:
a memory with stored instructions; and
a processor coupled to the memory and 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, 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.

### Claim 9 (depends on 8)

The encoder 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.

### Claim 10 (depends on 8)

The encoder 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 ofremaining first down-sampled samples.

### Claim 11 (depends on 8)

The encoder 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.

### Claim 12 (depends on 8)

The encoder 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.

### Claim 13 (depends on 8)

The encoder 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.

### Claim 14 (depends on 8)

The encoder 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.

### Claim 15

A decoder comprising:
a memory with stored instructions; and
a processor coupled to the memory and 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, 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.

### Claim 16 (depends on 15)

The decoder of claim 15, 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.

### Claim 17 (depends on 15)

The decoder of claim 15, 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.

### Claim 18 (depends on 15)

The decoder of claim 15, 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.

### Claim 19 (depends on 15)

The decoder of claim 15, 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.

### Claim 20 (depends on 15)

The decoder of claim 15, 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.