# US 12,764,286 B2 · Image encoding method and apparatus and image decoding method and apparatus

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- Number: US 12,764,286 B2
- Document ID: US12764286B2
- Status: Granted
- Kind: B2
- Application number: 19/029,779
- Filed: 2025-01-17
- Published: 2025-05-22
- Granted: 2026-10-13
- Earliest claimed: 2019-06-27
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Minsoo Park; Woongil Choi; Minwoo Park; Seungsoo Jeong; Kiho Choi; Narae Choi; Anish Tamse; Yinji Piao
- Web page: https://patentgrep.com/patent/US12764286B2

## CPC

- H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
- 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 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image encoding and decoding method and apparatus are provided. The image decoding method includes obtaining a difference quantization parameter for a current coding unit from a bitstream, based on an area of a predefined difference quantization parameter signaling unit; obtaining a quantization parameter for the current coding unit by using a predicted quantization parameter for the current coding unit and the difference quantization parameter for the current coding unit; obtaining at least one inverse-quantized coefficient by performing inverse-quantization on at least one coefficient obtained based on residual information of the current coding unit included in the bitstream, based on the quantization parameter for the current coding unit; obtaining a residual block of the current coding unit, based on the inverse-quantized coefficient; and obtaining a reconstructed block of the current coding unit, based on the residual block of the current coding unit.

## Claims

### Claim 1

An image decoding method performed by an apparatus, the method comprising:
obtaining at least one coding unit including a current coding unit by hierarchically splitting a current image;
determining a code value for a difference quantization parameter for the current coding unit as a first value, when a first flag indicating whether signaling for the difference quantization parameter is to be enabled indicates that the signaling for the difference quantization parameter is enabled and a second flag indicating whether a predefined signaling scheme of the difference quantization parameter is to be used indicates that the predefined signaling scheme of the difference quantization parameter is used and a split flag indicating whether or not to split the current coding unit indicates that the current coding unit is split and a split type of the current coding unit is a ternary split type and a sum of a value resulting from applying log 2 to a width of the current coding unit and a value resulting from applying log 2 to a height of the current coding unit is equal to a value resulting from adding 1 to a value resulting from applying log 2 to an area of a difference quantization parameter signaling unit;
obtaining the difference quantization parameter for the current coding unit based on information about a transform unit of the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the first value;
obtaining a quantization parameter for the current coding unit based on a predicted quantization parameter for the current coding unit and the difference quantization parameter for the current coding unit; and
obtaining a reconstructed block of the current coding unit, based on the quantization parameter for the current coding unit,
wherein the split flag indicates one of a binary split type and the ternary split type when the split flag indicates that the current coding unit is split, and
wherein the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit is determined based on information obtained from a Picture Parameter Set (PPS).

### Claim 2 (depends on 1)

The image decoding method of claim 1, further comprising:
when the first flag indicates that the signaling for the difference quantization parameter is enabled and the second flag indicates that the predefined signaling scheme of the difference quantization parameter is used,
when the split flag indicates that the current coding unit is not split, and
when the sum of the value resulting from applying log 2 to the width of the current coding unit and the value resulting from applying log 2 to the height of the current coding unit is larger than or equal to the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit,
determining the code value for the difference quantization parameter for the current coding unit as a second value; and
obtaining the difference quantization parameter for the current coding unit based on the information about the transform unit of the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the second value and a value of a coding block flag value of the transform unit of the current coding unit is equal to the second value.

### Claim 3 (depends on 1)

The image decoding method of claim 1, wherein a value indicating an area of the current coding unit is equal to a predefined multiple of a value indicating the area of the difference quantization parameter signaling unit, and
wherein the predefined multiple is two times.

### Claim 4

An image decoding apparatus comprising:
at least one processor configured to:
obtain at least one coding unit including a current coding unit by hierarchically splitting a current image;
determine a code value for a difference quantization parameter for the current coding unit as a first value, when a first flag indicating whether signaling for the difference quantization parameter is to be enabled indicates that the signaling for the difference quantization parameter is enabled and a second flag indicating whether a predefined signaling scheme of the difference quantization parameter is to be used indicates that the predefined signaling scheme of the difference quantization parameter is used and a split flag indicating whether or not to split the current coding unit indicates that the current coding unit is split and a split type of the current coding unit is a ternary split type and a sum of a value resulting from applying log 2 to a width of the current coding unit and a value resulting from applying log 2 to a height of the current coding unit is equal to a value resulting from adding 1 to a value resulting from applying log 2 to an area of a difference quantization parameter signaling unit;
obtain the difference quantization parameter for the current coding unit based on information about a transform unit of the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the first value;
obtain a quantization parameter for the current coding unit based on a predicted quantization parameter for the current coding unit and the difference quantization parameter for the current coding unit; and
obtain a reconstructed block of the current coding unit, based on the quantization parameter for the current coding unit,
wherein the split flag indicates one of a binary split type and the ternary split type when the split flag indicates that the current coding unit is split, and
wherein the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit is determined based on information obtained from a Picture Parameter Set (PPS).

### Claim 5 (depends on 4)

The image decoding apparatus of claim 4, wherein the at least one processor is further configured to:
when the first flag indicates that the signaling for the difference quantization parameter is enabled and the second flag indicates that the predefined signaling scheme of the difference quantization parameter is used,
when the split flag indicates that the current coding unit is not split, and
when the sum of the value resulting from applying log 2 to the width of the current coding unit and the value resulting from applying log 2 to the height of the current coding unit is larger than or equal to the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit,
determining the code value for the difference quantization parameter for the current coding unit as a second value; and
obtaining the difference quantization parameter for the current coding unit based on the information about the transform unit of the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the second value and a value of a coding block flag value of the transform unit of the current coding unit is equal to the second value.

### Claim 6 (depends on 4)

The image decoding apparatus of claim 4, wherein a value indicating an area of the current coding unit is equal to a predefined multiple of a value indicating the area of the difference quantization parameter signaling unit, and
wherein the predefined multiple is two times.

### Claim 7

An image encoding method performed by an apparatus, the method comprising:
obtaining at least one coding unit including a current coding unit by hierarchically splitting a current image;
obtaining a difference quantization parameter for the current coding unit, based on a predicted quantization parameter for the current coding unit and a quantization parameter for the current coding unit;
determining a code value for the difference quantization parameter for the current coding unit as a first value, when a first flag indicating whether signaling for the difference quantization parameter is to be enabled indicates that the signaling for the difference quantization parameter is enabled and a second flag indicating whether a predefined signaling scheme of the difference quantization parameter is to be used indicates that the predefined signaling scheme of the difference quantization parameter is used and a split flag indicating whether or not to split the current coding unit indicates that the current coding unit is split and a split type of the current coding unit is a ternary split type and a sum of a value resulting from applying log 2 to a width of the current coding unit and a value resulting from applying log 2 to a height of the current coding unit is equal to a value resulting from adding 1 to a value resulting from applying log 2 to an area of a difference quantization parameter signaling unit;
obtaining information about a transform unit of the current coding unit based on the difference quantization parameter for the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the first value; and
encoding the information about the transform unit of the current coding unit,
wherein the split flag indicates one of a binary split type and the ternary split type when the split flag indicates that the current coding unit is split, and
wherein the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit is determined based on information obtained from a Picture Parameter Set (PPS).

### Claim 8 (depends on 7)

The image encoding method of claim 7, wherein a value indicating an area of the current coding unit is equal to a predefined multiple of a value indicating the area of the difference quantization parameter signaling unit, and
wherein the predefined multiple is two times.

### Claim 9

An image encoding apparatus comprising:
at least one processor configured to:
obtain at least one coding unit including a current coding unit by hierarchically splitting a current image;
obtain a difference quantization parameter for the current coding unit, based on a predicted quantization parameter for the current coding unit and a quantization parameter for the current coding unit;
determine a code value for the difference quantization parameter for the current coding unit as a first value, when a first flag indicating whether signaling for the difference quantization parameter is to be enabled indicates that the signaling for the difference quantization parameter is enabled and a second flag indicating whether a predefined signaling scheme of the difference quantization parameter is to be used indicates that the predefined signaling scheme of the difference quantization parameter is used and a split flag indicating whether or not to split the current coding unit indicates that the current coding unit is split and a split type of the current coding unit is a ternary split type and a sum of a value resulting from applying log 2 to a width of the current coding unit and a value resulting from applying log 2 to a height of the current coding unit is equal to a value resulting from adding 1 to a value resulting from applying log 2 to an area of a difference quantization parameter signaling unit;
obtain information about a transform unit of the current coding unit based on the difference quantization parameter for the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the first value; and
encode the information about the transform unit of the current coding unit,
wherein the split flag indicates one of a binary split type and the ternary split type when the split flag indicates that the current coding unit is split, and
wherein the value resulting from applying log 2 to the area of the difference quantization parameter signaling unit is determined based on information obtained from a Picture Parameter Set (PPS).

### Claim 10 (depends on 9)

The image encoding apparatus of claim 9, wherein a value indicating an area of the current coding unit is equal to a predefined multiple of a value indicating the area of the difference quantization parameter signaling unit, and
wherein the predefined multiple is two times.