# US 12,225,201 B2 · Image or video coding based on temporal motion information in units of subblocks

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- Number: US 12,225,201 B2
- Document ID: US12225201B2
- Status: Granted
- Kind: B2
- Application number: 17/617,279
- Filed: 2020-06-11
- Published: 2022-07-21
- Granted: 2025-02-11
- Earliest claimed: 2019-06-11
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jie Zhao; Seunghwan Kim
- Web page: https://patentgrep.com/patent/US12225201B2

## CPC

- H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference
- 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 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
- 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 19/176: the region being a block, e.g. a macroblock
- H04N 19/513: Processing of motion vectors
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

According to the disclosure of this document, in subblock-based temporal motion vector prediction (sbTMVP), base motion information for a subblock for which a motion vector is not available can be efficiently derived, and through this, video/image coding efficiency can be improved.

## Claims

### Claim 1

An image decoding method performed by a decoding apparatus, the method comprising:
deriving reference subblocks on a collocated reference picture for subblocks of a current block;
deriving motion information for the subblocks of the current block based on motion information for the reference subblocks;
generating prediction samples based on the motion information for the subblocks of the current block; and
generating reconstructed samples based on the prediction samples,
wherein for a reference subblock in which a motion vector is not available among the reference subblocks, base motion information is derived, and
wherein the base motion information is used as the motion information for a subblock of the current block corresponding to the reference subblock,
wherein the base motion information is derived based on one of the reference subblocks in a reference block located corresponding to the current block on the collocated reference picture,
wherein the base motion information is derived based on a first reference subblock having an initially available motion vector, by checking whether a motion vector is available according to a determined order with respect to the reference subblocks in the reference block, and
wherein, based on the base motion information being not derived, a subblock-based temporal motion vector prediction (sbTMVP) is specified as available.

### Claim 2 (depends on 1)

The decoding method of claim 1, wherein the deriving of the reference subblocks comprises;
deriving a motion vector of a spatial neighboring block of the current block;
applying a motion shift to a location indicated by the motion vector of the spatial neighboring block at a center sample location of each of the subblocks of the current block; and
deriving each of the reference subblocks on the collocated reference picture corresponding to the motion-shifted location.

### Claim 3 (depends on 1)

The decoding method of claim 1, wherein the base motion information is used motion information derived based on a temporal neighboring block of the current block, and
the temporal neighboring block includes a reference block of the collocated reference picture corresponding to a bottom-right corner sample location of the current block or a reference block of the collocated reference picture corresponding to a center sample location of the current block.

### Claim 4 (depends on 3)

The decoding method of claim 3, wherein the temporal neighboring block is derived by being motion-shifted based on a motion vector derived from a spatial neighboring block of the current block.

### Claim 5

An image encoding method performed by an encoding apparatus, the method comprising:
deriving reference subblocks on a collocated reference picture for subblocks of a current block;
deriving motion information for the subblocks of the current block based on motion information for the reference subblocks;
generating prediction samples based on the motion information for the subblocks of the current block;
deriving residual samples based on the prediction samples; and
encoding image information including information on the residual samples,
wherein for a reference subblock in which a motion vector is not available among the reference subblocks, base motion information is derived, and
the base motion information is used as the motion information for a subblock of the current block corresponding to the reference subblock,
wherein the base motion information is derived based on one of the reference subblocks in a reference block located corresponding to the current block on the collocated reference picture,
wherein the base motion information is derived based on a first reference subblock having an initially available motion vector, by checking whether a motion vector is available according to a determined order with respect to the reference subblocks in the reference block, and
wherein, based on the base motion information being not derived, a subblock-based temporal motion vector prediction (sbTMVP) is specified as available.

### Claim 6 (depends on 5)

The encoding method of claim 5, wherein the deriving of the reference subblocks comprises;
deriving a motion vector of a spatial neighboring block of the current block;
applying a motion shift to a location indicated by the motion vector of the spatial neighboring block at a center sample location of each of the subblocks of the current block; and
deriving each of the reference subblocks on the collocated reference picture corresponding to the motion-shifted location.

### Claim 7 (depends on 5)

The encoding method of claim 5, wherein the base motion information is used motion information derived based on a temporal neighboring block of the current block, and
the temporal neighboring block includes a reference block of the collocated reference picture corresponding to a bottom-right corner sample location of the current block or a reference block of the collocated reference picture corresponding to a center sample location of the current block.

### Claim 8 (depends on 7)

The encoding method of claim 7, wherein the temporal neighboring block is derived by being motion-shifted based on a motion vector derived from a spatial neighboring block of the current block.

### Claim 9

A non-transitory computer-readable storage medium storing encoded information causing an image decoding apparatus to perform an image decoding method, wherein the decoding method comprises:
deriving reference subblocks on a collocated reference picture for subblocks of a current block;
deriving motion information for the subblocks of the current block based on motion information for the reference subblocks;
generating prediction samples based on the motion information for the subblocks of the current block; and
generating reconstructed samples based on the prediction samples,
wherein for a reference subblock in which a motion vector is not available among the reference subblocks, base motion information is derived, and
the base motion information is used as the motion information for a subblock of the current block corresponding to the reference subblock,
wherein the base motion information is derived based on one of the reference subblocks in a reference block located corresponding to the current block on the collocated reference picture,
wherein the base motion information is derived based on a first reference subblock having an initially available motion vector, by checking whether a motion vector is available according to a determined order with respect to the reference subblocks in the reference block, and
wherein, based on the base motion information being not derived, a subblock-based temporal motion vector prediction (sbTMVP) is specified as available.