# US 11,909,958 B2 · SbTMVP-based image or video coding

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- Number: US 11,909,958 B2
- Document ID: US11909958B2
- Status: Granted
- Kind: B2
- Application number: 18/079,660
- Filed: 2022-12-12
- Published: 2023-04-13
- Granted: 2024-02-20
- Earliest claimed: 2019-06-13
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Hyeongmoon Jang; Naeri Park; Junghak Nam
- Web page: https://patentgrep.com/patent/US11909958B2

## 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 19/52: by predictive encoding
- H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
- H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference
- 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: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

According to the disclosure of this document, in subblock-based temporal motion vector prediction (sbTMVP), a subblock position for deriving a motion vector in units of a subblock can be efficiently calculated, and through this, video/image coding efficiency can be improved and hardware implementation can be simplified.

## Claims

### Claim 1

An image decoding method performed by a decoding apparatus, the method comprising:
obtaining information on transform coefficients from a bitstream;
deriving a reference subblock on a collocated reference picture for a current subblock within a current block;
deriving a motion vector of the reference subblock;
deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on the motion vector of the reference subblock;
generating prediction samples based on a motion vector of the current subblock derived based on the sbTMVP candidate;
generating residual samples for the current block based on the information on the transform coefficients;
generating a reconstructed picture based on the prediction samples and the residual samples; and
applying a deblocking filtering on the reconstructed picture,
wherein the reference subblock on the collocated reference picture is derived based on a position of a center lower-right sample among four samples positioned at a center of the current subblock,
wherein for the reference subblock that is not available, the motion vector of the reference subblock is set as a base motion vector, and
wherein the base motion vector is derived on the collocated reference picture based on a position of a center lower-right sample among four samples located at a center of the current block.

### Claim 2

An image encoding method performed by an encoding apparatus, the method comprising:
deriving a reference subblock on a collocated reference picture for a current subblock within a current block;
deriving a motion vector of the reference subblock;
deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on the motion vector of the reference subblock;
generating prediction samples based on a motion vector of the current subblock derived based on the sbTMVP candidate;
generating residual samples based on the prediction samples;
generating information on transform coefficients based on the residual samples; and
encoding image information including the information on the transform coefficients,
wherein the reference subblock on the collocated reference picture is derived based on a position of a center lower-right sample among four samples positioned at a center of the current subblock,
wherein for the reference subblock that is not available, the motion vector of the reference subblock is set as a base motion vector, and
wherein the base motion vector is derived on the collocated reference picture based on a position of a center lower-right sample among four samples located at a center of the current block.

### Claim 3 (depends on 2)

A non-transitory computer-readable digital storage medium storing a bitstream generated by the image encoding method of claim 2.

### Claim 4

A transmission method of data for an image, the method comprising:
obtaining a bitstream for the image, wherein the bitstream is generated based on deriving a reference subblock on a collocated reference picture for a current subblock within a current block, deriving a motion vector of the reference subblock, deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on the motion vector of the reference subblock, generating prediction samples based on a motion vector of the current subblock derived based on the sbTMVP candidate, generating residual samples based on the prediction samples, generating information on transform coefficients based on the residual samples, and encoding image information including the information on the transform coefficients; and
transmitting the data comprising the bitstream,
wherein the reference subblock on the collocated reference picture is derived based on a position of a center lower-right sample among four samples positioned at a center of the current subblock,
wherein for the reference subblock that is not available, the motion vector of the reference subblock is set as a base motion vector, and
wherein the base motion vector is derived on the collocated reference picture based on a position of a center lower-right sample among four samples located at a center of the current block.