# US 12,015,779 B2 · Method and apparatus for deriving rice parameter in video/image coding system

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- Number: US 12,015,779 B2
- Document ID: US12015779B2
- Status: Granted
- Kind: B2
- Application number: 17/765,740
- Filed: 2020-10-06
- Published: 2022-11-24
- Granted: 2024-06-18
- Earliest claimed: 2019-10-07
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jungah Choi; Jin Heo; Sunmi Yoo; Jaehyun Lim; Jangwon Choi; Seunghwan Kim
- Web page: https://patentgrep.com/patent/US12015779B2

## CPC

- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/1883: {the unit relating to sub-band structure, e.g. hierarchical level, directional tree, e.g. low-high [LH], high-low [HL], high-high [HH]}
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A video decoding method performed by a decoding apparatus according to the present document may comprise the steps of: acquiring, from a bitstream, information indicating a level value of a transform coefficient in a current block; deriving a Rice parameter for the information indicating the level value of the transform coefficient, on the basis of a quantization parameter of the current block; deriving a bin string for the information indicating the level value of the transform coefficient, on the basis of the Rice parameter; and deriving the level value of the transform coefficient on the basis of the bin string.

## Claims

### Claim 1

A video decoding method performed by a decoding apparatus, the method comprising:
obtaining information representing a level value of a transform coefficient in a current block from a bitstream;
deriving a rice parameter for the information representing the level value of the transform coefficient based on a quantization parameter of the current block;
deriving a bin string for the information representing the level value of the transform coefficient based on the rice parameter; and
deriving the level value of the transform coefficient based on the bin string,
wherein the rice parameter is derived based on a maximum value of the rice parameter and a shift value for the quantization parameter.

### Claim 2 (depends on 1)

The video decoding method of claim 1, wherein the deriving the rice parameter is performed based on the current block being a transform skip block.

### Claim 3 (depends on 1)

The video decoding method of claim 1, wherein the information representing the level value of the transform coefficient comprises at least one of a dec_abs_level syntax element or an abs_remainder syntax element.

### Claim 4 (depends on 1)

The video decoding method of claim 1, wherein the deriving the rice parameter comprises:
comparing the quantization parameter of the current block with at least one threshold value; and
deriving the rice parameter based on a result of comparing the quantization parameter of the current block with the at least one threshold value.

### Claim 5 (depends on 4)

The video decoding method of claim 4, wherein the rice parameter for the information representing the level value of the transform coefficient is derived as a first rice parameter based on the quantization parameter of the current block being smaller than the at least one threshold value, and is derived as a second rice parameter based on the quantization parameter of the current block being equal to or larger than the at least one threshold value.

### Claim 6 (depends on 5)

The video decoding method of claim 5, wherein a value of the first rice parameter is larger than a value of the second rice parameter.

### Claim 7 (depends on 4)

The video decoding method of claim 4, wherein the at least one threshold value comprises at least one of 4, 8, 16, or 32.

### Claim 8 (depends on 1)

The video decoding method of claim 1, wherein the maximum value of the rice parameter is 5.

### Claim 9 (depends on 1)

The video decoding method of claim 1, wherein the rice parameter is derived as an integer value in a range of 0 to 5.

### Claim 10 (depends on 1)

The video decoding method of claim 1, wherein the rice parameter is derived based on a difference value between the maximum value of the rice parameter and the shift value for the quantization parameter.

### Claim 11 (depends on 1)

The video decoding method of claim 1, wherein the rice parameter is derived based on a following equation,
cRiceParam=Clip3(cRiceParammin,cRiceParammax,cRiceParammax−(QP>>n)),
where, cRiceParam represents the rice parameter, cRiceParammin represents a minimum value of the rice parameter, cRiceParammax represents the maximum value of the rice parameter, QP represents the quantization parameter, and n represents a predetermined integer value.

### Claim 12

A video encoding method performed by an encoding apparatus, the method comprising:
generating information representing a level value of a transform coefficient in a current block;
deriving a rice parameter for the information representing the level value of the transform coefficient based on a quantization parameter of the current block;
deriving a bin string for the information representing the level value of the transform coefficient based on the rice parameter; and
encoding the bin string,
wherein the rice parameter is derived based on a maximum value of the rice parameter and a shift value for the quantization parameter.

### Claim 13 (depends on 12)

The video encoding method of claim 12, wherein the deriving the rice parameter is performed based on the current block being a transform skip block.

### Claim 14 (depends on 12)

A non-transitory computer-readable digital storage medium storing a bitstream generated by the video encoding method of claim 12.

### Claim 15

A transmission method of data for an image, the method comprising:
obtaining a bitstream of the image, wherein the bitstream is generated based on generating information representing a level value of a transform coefficient in a current block, deriving a rice parameter for the information representing the level value of the transform coefficient based on a quantization parameter of the current block, deriving a bin string for the information representing the level value of the transform coefficient based on the rice parameter, and encoding the bin string; and
transmitting the data comprising the bitstream,
wherein the rice parameter is derived based on a maximum value of the rice parameter and a shift value for the quantization parameter.