# US 2021/0344948 A1 · Encoder, decoder, encoding method, and decoding method

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- Number: US 2021/0344948 A1
- Document ID: US20210344948A1
- Status: Published application
- Kind: A1
- Application number: 17/376,682
- Filed: 2021-07-15
- Published: 2021-11-04
- Earliest claimed: 2019-02-08
- Assignees: Panasonic Intellectual Property Corporation of America
- Applicants: Panasonic Intellectual Property Corporation of America
- Inventors: Kiyofumi ABE; Takahiro NISHI; Tadamasa TOMA; Yusuke KATO
- Web page: https://patentgrep.com/patent/US20210344948A1

## CPC

- H04N 19/52: by predictive encoding
- H04N 19/593: involving spatial prediction techniques
- H04N 19/103: Selection of coding mode or of prediction mode
- H04N 19/109: among a plurality of temporal predictive coding modes
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567)
- H04N 19/17: the unit being an image region, e.g. an object
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An encoder: generates, in an inter prediction mode, a first prediction image of a current block to be processed, based on a derived motion vector; and generates a final prediction image of the current block by applying an update process to the first prediction image. Candidates for the update process include a first process and a second process. The first process is a BDOF process. The second process is a process of mixing the first prediction image with a second prediction image generated in intra prediction for the current block. In the applying of the update process, the first process and the second process are mutually exclusively applied.

## Claims

### Claim 1

An encoder comprising:
circuitry; and
memory coupled to the circuitry, wherein
in operation, the circuitry:
generates, in an inter prediction mode, a first prediction image of a current block to be processed, based on a derived motion vector; and
generates a final prediction image of the current block by applying an update process to the first prediction image,
candidates for the update process include a first process and a second process,
the first process is a bi-directional optical flow (BDOF) process,
the second process is a process of mixing the first prediction image with a second prediction image generated in intra prediction for the current block, and
in the applying of the update process, the first process and the second process are mutually exclusively applied.

### Claim 2 (depends on 1)

The encoder according to claim 1, wherein
the circuitry:
in the applying of the update process,
determines whether the second process is to be applied to the first prediction image;
sets the second process as the update process when the second process is determined to be applied;
determines whether the first process is to be applied to the first prediction image when the second process is determined not to be applied; and
sets the first process as the update process when the first process is determined to be applied.

### Claim 3 (depends on 1)

The encoder according to claim 1, wherein
the circuitry
mutually exclusively performs the first process and the second process at a stage same as a stage of a reconstruction process, the stage being one stage included in a pipeline process for encoding an image, the reconstruction process being a process of generating a reconstructed image by performing addition of the final prediction image generated and a residual image.

### Claim 4

A decoder comprising:
circuitry; and
memory coupled to the circuitry, wherein
in operation, the circuitry:
generates, in an inter prediction mode, a first prediction image of a current block to be processed, based on a derived motion vector; and
generates a final prediction image of the current block by applying an update process to the first prediction image,
candidates for the update process include a first process and a second process,
the first process is a bi-directional optical flow (BDOF) process,
the second process is a process of mixing the first prediction image with a second prediction image generated in intra prediction for the current block, and
in the applying of the update process, the first process and the second process are mutually exclusively applied.

### Claim 5 (depends on 4)

The decoder according to claim 4, wherein
the circuitry:
in the applying of the update process,
determines whether the second process is to be applied to the first prediction image;
sets the second process as the update process when the second process is determined to be applied;
determines whether the first process is to be applied to the first prediction image when the second process is determined not to be applied; and
sets the first process as the update process when the first process is determined to be applied.

### Claim 6 (depends on 4)

The decoder according to claim 4, wherein
the circuitry
mutually exclusively performs the first process and the second process at a stage same as a stage of a reconstruction process, the stage being one stage included in a pipeline process for decoding an encoded image, the reconstruction process being a process of generating a reconstructed image by performing addition of the final prediction image generated and a residual image.

### Claim 7

An encoding method, comprising:
generating, in an inter prediction mode, a first prediction image of a current block to be processed, based on a derived motion vector; and
generating a final prediction image of the current block by applying an update process to the first prediction image, wherein
candidates for the update process include a first process and a second process,
the first process is a bi-directional optical flow (BDOF) process,
the second process is a process of mixing the first prediction image with a second prediction image generated in intra prediction for the current block, and
in the applying of the update process, the first process and the second process are mutually exclusively applied.

### Claim 8

A decoding method, comprising:
generating, in an inter prediction mode, a first prediction image of a current block to be processed, based on a derived motion vector; and
generating a final prediction image of the current block by applying an update process to the first prediction image, wherein
candidates for the update process include a first process and a second process,
the first process is a bi-directional optical flow (BDOF) process,
the second process is a process of mixing the first prediction image with a second prediction image generated in intra prediction for the current block, and
in the applying of the update process, the first process and the second process are mutually exclusively applied.