# US 2025/0159136 A1 · Image decoding device, image decoding method, and program

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- Number: US 2025/0159136 A1
- Document ID: US20250159136A1
- Status: Published application
- Kind: A1
- Application number: 19/021,693
- Filed: 2025-01-15
- Published: 2025-05-15
- Earliest claimed: 2019-03-11
- Assignees: Kddi Corporation
- Applicants: Kddi Corporation
- Inventors: Kyohei UNNO; Kei KAWAMURA; Sei NAITO
- Web page: https://patentgrep.com/patent/US20250159136A1

## 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 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/513: Processing of motion vectors
- H04N 19/521: {for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors}
- H04N 19/537: Motion estimation other than block-based
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image decoding device includes: a motion vector decoding unit that decodes a motion vector from encoded data; a refinement unit that performs refinement processing to correct the decoded motion vector; and a predictive signal generation unit that generates a predictive signal on the basis of the corrected motion vector outputted from the refinement unit. The predictive signal generation unit determines whether or not to apply BDOF processing for each block, on the basis of information calculated in the course of the refinement processing.

## Claims

### Claim 1

An image decoding device, comprising:
a motion vector decoding unit that decodes a motion vector from encoded data;
a refinement unit that performs refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision, and
a predictive signal generation unit that generates a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
the predictive signal generation unit determines whether or not to perform BDOF processing for each sub-block to which the refinement processing is to be performed, on the basis of information calculated in the course of the refinement processing,
the sub-block is generated by splitting a block,
the predictive signal generation unit determines, for each of the sub-blocks, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value,
the predictive signal generation unit provides a decoded image, and
the refinement unit performs the refinement processing for each sub-block.

### Claim 2

An image decoding method, comprising the steps of:
(A) decoding a motion vector from encoded data;
(B) performing refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision, and
(C) generating a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
it is determined in the step (C), for each sub-block to which the refinement processing is to be performed, whether or not to perform BDOF processing, on the basis of information calculated in the course of the refinement processing,
the sub-block is generated by splitting a block, it is determined in the step (C), for each sub-block, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value,
the predictive signal is a decoded image, and
in the step (B), the refinement processing is performed for each sub-block.

### Claim 3

A non-transitory computer readable medium having stored thereon instructions comprising executable code, which when executed by at least one processor, cause a computer to execute the steps of:
(A) decoding a motion vector from encoded data;
(B) performing refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision, and
(C) generating a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
it is determined in step (C), for each sub-block to which the refinement processing is to be performed, whether or not to perform BDOF processing, on the basis of information calculated in the course of the refinement processing,
the sub-block is generated by splitting a block,
it is determined in the step (C), for each sub-block, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value,
the predictive signal is a decoded image, and
the refinement unit performs the refinement processing for each sub-block.