# US 2022/0286701 A1 · Image or video coding based on palette mode

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2022/0286701 A1
- Document ID: US20220286701A1
- Status: Published application
- Kind: A1
- Application number: 17/638,787
- Filed: 2020-08-26
- Published: 2022-09-08
- Earliest claimed: 2019-08-26
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jie ZHAO; Seethal PALURI; Seunghwan KIM
- Web page: https://patentgrep.com/patent/US20220286701A1

## CPC

- H04N 19/103: Selection of coding mode or of prediction mode
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/124: Quantisation
- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- 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 19/18: the unit being a set of transform coefficients
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/463: by compressing encoding parameters before transmission
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

According to the disclosure of the present documents, a quantization parameter used in a scaling process of a quantized escape value in a palette mode may be derived on the basis of minimum quantization parameter information relating to a transform skip mode. Accordingly, the amount of data required to be signaled for video/image coding can be reduced and escape coding in a palette mode can be effectively performed.

## Claims

### Claim 1

An image decoding method performed by a decoding apparatus, the method comprising:
obtaining image information including quantized escape value information in a palette mode from a bitstream;
deriving an escape value for a current block based on the quantized escape value information; and
generating reconstructed samples based on the escape value,
wherein the escape value is derived based on the quantized escape value information and a quantization parameter,
wherein the quantization parameter is derived based on information on a minimum quantization parameter for a transform skip mode.

### Claim 2 (depends on 1)

The image decoding method of claim 1, wherein the image information includes a sequence parameter set (SPS),
wherein the SPS includes the information on the minimum quantization parameter for the transform skip mode.

### Claim 3 (depends on 1)

The image decoding method of claim 1, wherein the quantization parameter includes a value greater than or equal to a minimum quantization parameter value derived from the information on the minimum quantization parameter for the transform skip mode.

### Claim 4 (depends on 1)

The image decoding method of claim 1, wherein a range of the quantized escape value information is determined based on a bit depth (BitDepth).

### Claim 5 (depends on 4)

The image decoding method of claim 4, wherein the bit depth includes a bit depth for a luma component BitDepthY and a bit depth for a chroma component BitDepthC,
a range of the quantized escape value information for the luma component has a value between 0 and (1<<BitDepthY)−1, and
a range of the quantized escape value information for the chroma component has a value between 0 and (1<<BitDepthC)−1.

### Claim 6 (depends on 1)

The image decoding method of claim 1, wherein the image information includes palette size information related to a maximum index of a palette table,
wherein the palette size information is a predetermined value or is determined based on a size of a coding unit.

### Claim 7 (depends on 1)

The image decoding method of claim 1, further comprising:
configuring a palette table based on palette entry information;
configuring a palette index map for the current block based on palette index information;
deriving a sample value for a palette entry in the palette table based on the palette index map; and
generating the reconstructed samples based on the palette index map and the sample value for the palette entry,
wherein the image information includes the palette entry information and the palette index information.

### Claim 8

An image encoding method performed by an encoding apparatus, the method comprising:
deriving an escape value in a palette mode for a current block;
deriving a quantized escape value based on the escape value; and
encoding image information including the quantized escape value information,
wherein the quantized escape value is derived based on a quantization parameter for the escape value in the current block,
wherein the quantization parameter is derived based on information on a minimum quantization parameter for a transform skip mode.

### Claim 9 (depends on 8)

The image encoding method of claim 8, wherein the image information includes a sequence parameter set (SPS),
wherein the SPS includes the information on the minimum quantization parameter for the transform skip mode.

### Claim 10 (depends on 8)

The image encoding method of claim 8, wherein the quantization parameter has a value greater than or equal to a minimum quantization parameter value derived from the information on the minimum quantization parameter for the transform skip mode.

### Claim 11 (depends on 8)

The image encoding method of claim 8, wherein a range of the quantized escape value information is determined based on a bit depth (BitDepth).

### Claim 12 (depends on 11)

The image encoding method of claim 11, wherein the bit depth includes a bit depth for a luma component BitDepthY and a bit depth for a chroma component BitDepthC,
a range of the quantized escape value information for the luma component has a value between 0 and (1<<BitDepthY)−1, and
a range of the quantized escape value information for the chroma component has a value between 0 and (1<<BitDepthC)−1.

### Claim 13 (depends on 8)

The image encoding method of claim 8, wherein the image information includes palette size information related to a maximum index of a palette table,
wherein the palette size information is a predetermined value or is determined based on a size of a coding unit.

### Claim 14 (depends on 8)

The image encoding method of claim 8, further comprising:
generating palette entry information based on sample values of the current block;
generating palette index information for the current block based on the palette entry information; and
encoding the image information including the palette entry information and the palette index information.

### Claim 15

A non-transitory computer-readable storage medium storing a bitstream generated by a method, the method comprising: performing deriving an escape value in a palette mode for a current block, deriving a quantized escape value based on the escape value, and generating the bitstream by encoding image information including the quantized escape value information,
wherein the quantized escape value is derived based on a quantization parameter for the escape value in the current block,
wherein the quantization parameter is derived based on information on a minimum quantization parameter for a transform skip mode.