# US 2025/0168356 A1 · Image encoding/decoding method and apparatus, and recording medium for storing bitstream

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

- Number: US 2025/0168356 A1
- Document ID: US20250168356A1
- Status: Published application
- Kind: A1
- Application number: 19/030,542
- Filed: 2025-01-17
- Published: 2025-05-22
- Earliest claimed: 2017-09-29
- Assignees: Lx Semicon Co., Ltd.
- Applicants: LX Semicon Co., Ltd.
- Inventors: Dong San JUN; Jung Won KANG; Hyun Suk KO; Sung Chang LIM; Jin Ho LEE; Ha Hyun LEE; Hui Yong KIM
- Web page: https://patentgrep.com/patent/US20250168356A1

## CPC

- H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567)
- H04N 19/52: by predictive encoding
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image decoding/encoding method and apparatus are discussed. The image decoding method can include obtaining residual information and information for a collocated picture of a current block, deriving the collocated picture of the current block based on the information for the collocated picture, and determining whether a collocated block in the collocated picture is available as a temporal merge candidate of the current block based on a prediction mode of the collocated block.

## Claims

### Claim 1

An image decoding method performed by a decoding apparatus, the method comprising:
obtaining residual information and information for a collocated picture of a current block;
deriving the collocated picture of the current block based on the information for the collocated picture;
determining whether a collocated block in the collocated picture is available as a temporal merge candidate of the current block based on a prediction mode of the collocated block;
based on the collocated block being available as the temporal merge candidate, deriving the temporal merge candidate of the current block based on motion information of the collocated block;
generating a merge candidate list based on the temporal merge candidate of the current block;
deriving motion information of the current block based on the merge candidate list;
deriving a prediction sample of the current block based on the motion information;
deriving a residual sample of the current block based on the residual information; and
generating a reconstructed picture based on the prediction sample and the residual sample,
wherein based on the prediction mode of the collocated block being a current picture referencing (CPR) mode, the collocated block is not available as the temporal merge candidate, and
wherein the CPR mode is a prediction mode in which a current picture including the current block is used as a reference picture.

### Claim 2

An image encoding method performed by an encoding apparatus, the method comprising:
deriving a collocated picture of a current block;
determining whether a collocated block in the collocated picture is available as a temporal merge candidate of the current block based on a prediction mode of the collocated block;
based on the collocated block being available as the temporal merge candidate, deriving the temporal merge candidate of the current block based on motion information of the collocated block;
generating a merge candidate list based on the temporal merge candidate of the current block;
deriving motion information of the current block based on the merge candidate list;
deriving a prediction sample of the current block based on the motion information;
deriving a residual sample of the current block based on the prediction sample; and
encoding image information including residual information and information for the collocated picture of the current block,
wherein based on the prediction mode of the collocated block being a current picture referencing (CPR) mode, the collocated block is not available as the temporal merge candidate, and
wherein the CPR mode is a prediction mode in which a current picture including the current block is used as a reference picture.

### Claim 3

A transmission method for image data, the method comprising:
obtaining a bitstream of encoded image information, wherein the encoded image information is generated based on deriving a collocated picture of a current block, determining whether a collocated block in the collocated picture is available as a temporal merge candidate of the current block based on a prediction mode of the collocated block, based on the collocated block being available as the temporal merge candidate, deriving the temporal merge candidate of the current block based on motion information of the collocated block, generating a merge candidate list based on the temporal merge candidate of the current block, deriving motion information of the current block based on the merge candidate list, deriving a prediction sample of the current block based on the motion information, deriving a residual sample of the current block based on the prediction sample, and encoding the image information including residual information and information for the collocated picture of the current block; and
transmitting the image data comprising the bitstream,
wherein based on the prediction mode of the collocated block being a current picture referencing (CPR) mode, the collocated block is not available as the temporal merge candidate, and
wherein the CPR mode is a prediction mode in which a current picture including the current block is used as a reference picture.