# US 12,598,296 B2 · Video decoding method using bi-prediction and device therefor

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- Number: US 12,598,296 B2
- Document ID: US12598296B2
- Status: Granted
- Kind: B2
- Application number: 18/882,258
- Filed: 2024-09-11
- Published: 2025-01-02
- Granted: 2026-04-07
- Earliest claimed: 2019-06-24
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Naeri Park; Junghak Nam; Hyeongmoon Jang
- Web page: https://patentgrep.com/patent/US12598296B2

## CPC

- H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
- H04N 19/109: among a plurality of temporal predictive coding modes
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513)
- H04N 19/527: Global motion vector estimation
- H04N 19/573: Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
- 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 document, when the inter-prediction type of the current block indicates biprediction, weight index information for a candidate in a merge candidate list or sub-block merge candidate list can be derived, and coding efficiency can be raised.

## Claims

### Claim 1

An image decoding method performed by a decoding apparatus, comprising:
obtaining image information including inter-prediction mode information and residual information through a bitstream;
generating a sub-block merge candidate list of a current block based on the inter-prediction mode information;
selecting one candidate from among the candidates included in the sub-block merge candidate list;
generating prediction samples of the current block based on a weight index for the selected candidate;
generating residual samples based on the residual information; and
generating reconstructed samples based on the prediction samples and the residual samples,
wherein the sub-block merge candidate list includes an inherited affine merge candidate and a constructed affine merge candidate,
wherein the inherited affine merge candidate is derived based on control point motion vectors of a neighboring block of the current block,
wherein the constructed affine merge candidate is generated based on at least two of a control point CP0 related to a top-left corner of the current block, a control point CP1 related to a top-right corner of the current block, a control point CP2 related to a bottom-left corner of the current block and a control point CP3 related to a bottom-right corner of the current block,
wherein based on a case that the constructed affine merge candidate is generated based on {CP0, CP2}, a weight index for the constructed affine merge candidate is equal to a weight index for the CP0,
wherein based on a case that the constructed affine merge candidate is generated based on {CP1, CP2, CP3}, the weight index for the constructed affine merge candidate is equal to a weight index for the CP1, and
wherein the constructed affine merge candidate is inserted after the inherited affine merge candidate in the sub-block merge candidate list.

### Claim 2

An image encoding method performed by an encoding apparatus, comprising:
determining an inter-prediction mode of a current block and generating inter prediction mode information indicating the inter-prediction mode;
generating a sub-block merge candidate list of the current block based on the inter-prediction mode;
generating selection information indicating one of candidates included in the sub-block merge candidate list;
generating residual information based on residual samples; and
encoding image information including the inter-prediction mode information, the selection information and the residual information,
wherein the sub-block merge candidate list includes an inherited affine merge candidate and a constructed affine merge candidate,
wherein the inherited affine merge candidate is derived based on control point motion vectors of a neighboring block of the current block,
wherein the constructed affine merge candidate is generated based on at least two of a control point CP0 related to a top-left corner of the current block, a control point CP1 related to a top-right corner of the current block, a control point CP2 related to a bottom-left corner of the current block and a control point CP3 related to a bottom-right corner of the current block,
wherein based on a case that the constructed affine merge candidate is generated based on {CP0, CP2}, a weight index for the constructed affine merge candidate is equal to a weight index for the CP0,
wherein based on a case that the constructed affine merge candidate is generated based on {CP1, CP2, CP3}, the weight index for the constructed affine merge candidate is equal to a weight index for the CP1, and
wherein the constructed affine merge candidate is inserted after the inherited affine merge candidate in the sub-block merge candidate list.

### Claim 3

A transmission method for data, the method comprising:
obtaining, by a transmission apparatus, a bitstream for the image, wherein the bitstream is generated based on determining an inter-prediction mode of a current block and generating inter prediction mode information indicating the inter-prediction mode, generating a sub-block merge candidate list of the current block based on the inter-prediction mode, generating selection information indicating one of candidates included in the sub-block merge candidate list, generating residual information based on residual samples and encoding image information including the inter-prediction mode information, the selection information and the residual information; and
transmitting, by the transmitting apparatus, the data comprising the bitstream,
wherein the sub-block merge candidate list includes an inherited affine merge candidate and a constructed affine merge candidate,
wherein the inherited affine merge candidate is derived based on control point motion vectors of a neighboring block of the current block,
wherein the constructed affine merge candidate is generated based on at least two of a control point CP0 related to a top-left corner of the current block, a control point CP1 related to a top-right corner of the current block, a control point CP2 related to a bottom-left corner of the current block and a control point CP3 related to a bottom-right corner of the current block,
wherein based on a case that the constructed affine merge candidate is generated based on {CP0, CP2}, a weight index for the constructed affine merge candidate is equal to a weight index for the CP0,
wherein based on a case that the constructed affine merge candidate is generated based on {CP1, CP2, CP3}, the weight index for the constructed affine merge candidate is equal to a weight index for the CP1, and
wherein the constructed affine merge candidate is inserted after the inherited affine merge candidate in the sub-block merge candidate list.