# US 2021/0243432 A1 · Video image encoding and decoding method, apparatus, and device

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- Number: US 2021/0243432 A1
- Document ID: US20210243432A1
- Status: Published application
- Kind: A1
- Application number: 17/234,976
- Filed: 2021-04-20
- Published: 2021-08-05
- Earliest claimed: 2017-08-11
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Huanbang Chen; Hong Zhang; Haitao Yang
- Web page: https://patentgrep.com/patent/US20210243432A1

## 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 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
- 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 19/517: by encoding
- H04N 19/523: with sub-pixel accuracy
- H04N 19/54: using feature points or meshes
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present disclosure provides a video image decoding method in which a size of an affine motion compensation image sub-block in an affine image block is determined based on a motion vector difference, motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, where the size includes a length in a horizontal direction and a length in a vertical direction, so that a length of the affine image block in a horizontal/vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal/vertical direction.

## Claims

### Claim 1

A video image decoding method, comprising:
determining a size of an affine motion compensation image sub-block in an affine image block based on a motion vector difference of the affine image block, a motion vector precision of the affine image block, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in a horizontal direction is an integer multiple of a length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in a vertical direction is an integer multiple of a length of the affine motion compensation image sub-block in the vertical direction; and the control points each have a motion vector for determining the motion vector difference; and
performing decoding processing on the affine image block based on the size of the affine motion compensation image sub-block.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction and the length of the affine motion compensation image sub-block in the vertical direction, wherein both the lengths of the affine motion compensation image sub-block in the horizontal direction and the vertical direction are an integer number of pixels;
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction and the length of the affine motion compensation image sub-block in the horizontal direction, wherein both the lengths of the affine motion compensation image sub-block in the vertical direction and the horizontal direction are an integer number of pixels;
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction; and
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction, wherein the length of the affine motion compensation image sub-block in the horizontal direction is an integer number of pixels;
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
proportionally adjusting a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction, wherein the length of the affine motion compensation image sub-block in the vertical direction is an integer number of pixels; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 5 (depends on 2)

The method according to claim 2, further comprising determining at least one of that the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, or that the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and wherein
the adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction comprises:
adjusting, that is, increasing/decreasing, the length of the affine motion compensation image sub-block in the horizontal direction by one or more pixels; and
determining whether the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the horizontal direction, repeating the adjusting and determining steps until the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
the adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction comprises:
adjusting, that is, increasing/decreasing, the length of the affine motion compensation image sub-block in the vertical direction by one or more pixels; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the vertical direction, repeating the adjusting and determining steps until the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 6

A video image encoding method, comprising:
determining a size of an affine motion compensation image sub-block in an affine image block based on a motion vector difference of the affine image block, a motion vector precision of the affine image block, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in a horizontal direction is an integer multiple of a length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in a vertical direction is an integer multiple of a length of the affine motion compensation image sub-block in the vertical direction; and the control points each have a motion vector for determining the motion vector difference; and
performing encoding processing on the affine image block based on the size of the affine motion compensation image sub-block.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction and the length of the affine motion compensation image sub-block in the vertical direction, wherein both the lengths of the affine motion compensation image sub-block in the horizontal direction and the vertical direction are an integer number of pixels;
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 8 (depends on 6)

The method according to claim 6, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction and the length of the affine motion compensation image sub-block in the horizontal direction, wherein both the lengths of the affine motion compensation image sub-block in the vertical direction and the horizontal direction are an integer number of pixels;
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction; and
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction.

### Claim 9 (depends on 6)

The method according to claim 6, wherein the determining a size of an affine motion compensation image sub-block in the affine image block based on the motion vector difference, the motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction comprises:
proportionally adjusting a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction, wherein the length of the affine motion compensation image sub-block in the horizontal direction is an integer number of pixels;
determining whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
proportionally adjusting a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction, wherein the length of the affine motion compensation image sub-block in the vertical direction is an integer number of pixels; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 10 (depends on 7)

The method according to claim 7, further comprising determining at least one of that the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, or that the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and wherein
the adjusting the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction comprises:
adjusting, that is, increasing/decreasing, the length of the affine motion compensation image sub-block in the horizontal direction by one or more pixels; and
determining whether the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the horizontal direction, repeating the adjusting and determining steps until the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
the adjusting the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction comprises:
adjusting, that is, increasing/decreasing, the length of the affine motion compensation image sub-block in the vertical direction by one or more pixels; and
determining whether the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the vertical direction, repeating the adjusting and determining steps until the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 11

A video image decoding apparatus, comprising:
an image sub-block size determining module, configured to determine a size of an affine motion compensation image sub-block in an affine image block based on the motion vector difference of the affine image block, the motion vector precision of the affine image block, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in a horizontal direction is an integer multiple of a length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in a vertical direction is an integer multiple of a length of the affine motion compensation image sub-block in the vertical direction; and the control points each has a motion vector for determining the motion vector difference; and
a decoding module, configured to perform decoding processing on the affine image block based on the size of the affine motion compensation image sub-block.

### Claim 12 (depends on 11)

The apparatus according to claim 11, wherein the image sub-block size determining module is configured to:
proportionally adjust a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction and the length of the affine motion compensation image sub-block in the vertical direction, wherein both the lengths of the affine motion compensation image sub-block in the horizontal direction and the vertical direction are an integer number of pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 13 (depends on 11)

The apparatus according to claim 11, wherein the image sub-block size determining module is configured to:
proportionally adjust a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction and the length of the affine motion compensation image sub-block in the horizontal direction, wherein both the lengths of the affine motion compensation image sub-block in the vertical direction and the horizontal direction are an integer number of pixels;
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction; and
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction.

### Claim 14 (depends on 11)

The apparatus according to claim 11, wherein the image sub-block size determining module is configured to:
proportionally adjust a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction, wherein the length of the affine motion compensation image sub-block in the horizontal direction is an integer number of pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
proportionally adjust a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction, wherein the length of the affine motion compensation image sub-block in the vertical direction is an integer number of pixels; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 15 (depends on 12)

The apparatus according to claim 12, wherein the image sub-block size determining module is further configured to:
adjust, that is, increase/decrease, the length of the affine motion compensation image sub-block in the horizontal direction by one or more pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the horizontal direction, repeat the adjusting and determining steps until the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
adjust, that is, increase/decrease, the length of the affine motion compensation image sub-block in the vertical direction by one or more pixels; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the vertical direction, repeat the adjusting and determining steps until the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 16

A video image encoding apparatus, comprising:
an image sub-block size determining module, configured to determine a size of an affine motion compensation image sub-block in an affine image block based on a motion vector difference, a motion vector precision of the affine image block, a distance between control points of the affine image block in the affine image block, and a size of the affine image block, so that a length of the affine image block in a horizontal direction is an integer multiple of a length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in a vertical direction is an integer multiple of a length of the affine motion compensation image sub-block in the vertical direction; and the control points each have a motion vector for determining the motion vector difference; and
an encoding module, configured to perform encoding processing on the affine image block based on the size of the affine motion compensation image sub-block.

### Claim 17 (depends on 16)

The apparatus according to claim 16, wherein the image sub-block size determining module is configured to:
proportionally adjust a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction and the length of the affine motion compensation image sub-block in the vertical direction, wherein both the lengths of the affine motion compensation image sub-block in the horizontal direction and the vertical direction are an integer number of pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 18 (depends on 16)

The apparatus according to claim 16, wherein the image sub-block size determining module is configured to:
proportionally adjust a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction and the length of the affine motion compensation image sub-block in the horizontal direction, wherein both the lengths of the affine motion compensation image sub-block in the vertical direction and the horizontal direction are an integer number of pixels;
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction; and
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction.

### Claim 19 (depends on 16)

The method according to claim 16, wherein the image sub-block size determining module is configured to:
proportionally adjust a first horizontal distance based on a proportion of the motion vector precision to a first component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the horizontal direction, wherein the length of the affine motion compensation image sub-block in the horizontal direction is an integer number of pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the length of the affine motion compensation image sub-block in the horizontal direction, adjust the length of the affine motion compensation image sub-block in the horizontal direction, so that the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
proportionally adjust a first vertical distance based on a proportion of the motion vector precision to a second component of the motion vector difference, to obtain the length of the affine motion compensation image sub-block in the vertical direction, wherein the length of the affine motion compensation image sub-block in the vertical direction is an integer number of pixels; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the length of the affine motion compensation image sub-block in the vertical direction, adjust the length of the affine motion compensation image sub-block in the vertical direction, so that the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 20 (depends on 17)

The apparatus according to claim 17, wherein the image sub-block size determining module is further configured to:
adjust, that is, increase/decrease, the length of the affine motion compensation image sub-block in the horizontal direction by one or more pixels;
determine whether the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction, and if the length of the affine image block in the horizontal direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the horizontal direction, repeat the adjusting and determining steps until the length of the affine image block in the horizontal direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the horizontal direction;
adjust, that is, increase/decrease, the length of the affine motion compensation image sub-block in the vertical direction by one or more pixels; and
determine whether the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction, and if the length of the affine image block in the vertical direction is not an integer multiple of the adjusted length of the affine motion compensation image sub-block in the vertical direction, repeat the adjusting and determining steps until the length of the affine image block in the vertical direction is an integer multiple of an adjusted length of the affine motion compensation image sub-block in the vertical direction.

### Claim 21

A non-transitory computer-readable medium for storing bit string of a video, comprising:
a bit string stored in the non-transitory computer-readable medium, the bit string comprising an encoded sequence of frames of a video, wherein the sequence of frames is encoded into the bit string based on a plurality of operations comprising:
determining a size of an affine motion compensation image sub-block in an affine image block based on a motion vector difference of the affine image block, a motion vector precision of the affine image block, a distance between control points in the affine image block, and a size of the affine image block, so that a length of the affine image block in a horizontal direction is an integer multiple of a length of the affine motion compensation image sub-block in the horizontal direction, and a length of the affine image block in a vertical direction is an integer multiple of a length of the affine motion compensation image sub-block in the vertical direction; and the control points each have a motion vector for determining the motion vector difference; and
performing encoding processing on the affine image block based on the size of the affine motion compensation image sub-block.