# US 12,604,009 B2 · Image encoding/decoding method and apparatus

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- Number: US 12,604,009 B2
- Document ID: US12604009B2
- Status: Granted
- Kind: B2
- Application number: 18/810,399
- Filed: 2024-08-20
- Published: 2024-12-12
- Granted: 2026-04-14
- Earliest claimed: 2019-06-21
- Assignees: Electronics and Telecommunications Research Institute; Industry-University Cooperation Foundation Korea Aerospace University
- Applicants: Electronics and Telecommunications Research Institute; Industry-University Cooperation Foundation Korea Aerospace University
- Inventors: Jin Ho Lee; Jung Won Kang; Ha Hyun Lee; Sung Chang Lim; Hui Yong Kim; Jae Gon Kim; Do Hyeon Park; Ji Hoon Do; Yong Uk Yoon
- Web page: https://patentgrep.com/patent/US12604009B2

## CPC

- H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence)
- H04N 19/12: Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
- 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 19/60: using transform coding
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Disclosed herein are an image encoding/decoding method and apparatus. The image decoding method of the present disclosure may include obtaining maximum transform block size information, deriving a maximum transform block size on the basis of the maximum transform block size information, and, determining whether or not a secondary inverse transform is applied to the current block on the basis of the maximum transform block size and a horizontal size and a vertical size of a current block.

## Claims

### Claim 1

An image decoding method, the method comprising:
obtaining maximum transform block size information;
deriving a maximum transform block size on the basis of the maximum transform block size information;
determining whether or not a secondary inverse transform is applied to a current block based on the maximum transform block size, and a horizontal size and a vertical size of the current block; and
obtaining first transform coefficients of the current block by performing the secondary inverse transform on second transform coefficients of the current block in response to determination to apply the secondary inverse transform to the current block,
wherein the determining of whether or not the secondary inverse transform is applied comprises determining that the secondary inverse transform is not applied to the current block when a prediction mode of the current block is an inter-prediction mode, and
wherein the determining of whether or not the secondary inverse transform is applied comprises determining whether or not the secondary inverse transform is applied to the current block based on primary inverse transform information of the current block indicating whether a primary transform is skipped for the current block.

### Claim 2

An image encoding method, the method comprising:
determining a maximum transform block size;
encoding maximum transform block size information indicating the maximum transform block size;
determining whether or not a secondary transform is applied to a current block based on the maximum transform block size, and a horizontal size and a vertical size of the current block; and
generating second transform coefficients of the current block by performing the secondary transform on first transform coefficients of the current block in response to determination to apply the secondary transform to the current block,
wherein the determining of whether or not the secondary transform is applied comprises determining that the secondary transform is not applied to the current block when a prediction mode of the current block is an inter-prediction mode, and
wherein the determining of whether or not the secondary transform is applied comprises determining whether or not the secondary transform is applied to the current block based on primary transform information of the current block indicating whether a primary transform is skipped for the current block.

### Claim 3

A method of transmitting data comprising a bitstream for an image, the method comprising:
obtaining the bitstream for the image; and
transmitting the data comprising the bitstream,
wherein the bitstream is generated by performing:
determining a maximum transform block size;
encoding maximum transform block size information indicating the maximum transform block size;
determining whether or not a secondary transform is applied to a current block based on the maximum transform block size, and a horizontal size and a vertical size of the current block; and
generating second transform coefficients of the current block by performing the secondary transform on first transform coefficients of the current block in response to determination to apply the secondary transform to the current block,
wherein the determining of whether or not the secondary inverse transform is applied comprises determining that the secondary inverse transform is not applied to the current block when a prediction mode of the current block is an inter-prediction mode, and
wherein the determining of whether or not the secondary transform is applied comprises determining whether or not the secondary transform is applied to the current block based on primary transform information of the current block indicating whether a primary transform is skipped for the current block.