# US 12,225,240 B2 · Image encoding/decoding method and device

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- Number: US 12,225,240 B2
- Document ID: US12225240B2
- Status: Granted
- Kind: B2
- Application number: 18/513,906
- Filed: 2023-11-20
- Published: 2024-03-21
- Granted: 2025-02-11
- Earliest claimed: 2016-07-13
- Assignees: Electronics and Telecommunications Research Institute; Industry Academy Cooperation Foundation of Sejong University
- Applicants: Electronics and Telecommunications Research Institute; Industry Academy Cooperation Foundation of Sejong University
- Inventors: Sung Chang Lim; Jung Won Kang; Hyun Suk Ko; Jin Ho Lee; Dong San Jun; Ha Hyun Lee; Seung Hyun Cho; Hui Yong Kim; Jin Soo Choi; Yung Lyul Lee; Jun Woo Choi
- Web page: https://patentgrep.com/patent/US12225240B2

## CPC

- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/146: Data rate or code amount at the encoder output
- H04N 19/149: by estimating the code amount by means of a model, e.g. mathematical model or statistical model
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/167: Position within a video image, e.g. region of interest [ROI]
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/182: the unit being a pixel
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/649: {the transform being applied to non rectangular image segments}
- H04N 19/88: involving rearrangement of data among different coding units, e.g. shuffling, interleaving, scrambling or permutation of pixel data or permutation of transform coefficient data among different blocks
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present invention relates to an image encoding/decoding method and apparatus. An image encoding method according to the present invention may comprise generating a transform block by performing at least one of transform and quantization; grouping at least one coefficient included in the transform block into at least one coefficient group (CG); scanning at least one coefficient included in the coefficient group; and encoding the at least one coefficient.

## Claims

### Claim 1

An image encoding method, comprising:
performing prediction for a current block using a prediction mode for the current block;
determining a transform kernel of the current block;
generating at least one coefficient of the current block by performing a transform on residual samples of the current block, based on the transform kernel; and
encoding transform kernel information indicating the transform kernel of the current block and the at least one coefficient of the current block,
wherein the transform comprises a primary transform and a secondary transform,
the at least one coefficient is generated by performing the secondary transform on a result of the primary transform on the residual samples using the transform kernel of the current block,
the transform kernel information indicates one of predefined transform kernel sets as the transform kernel of the current block,
each of the predefined transform kernel sets comprises a predefined horizontal transform kernel and a predefined vertical transform kernel,
the transform kernel of the current block comprises a horizontal transform kernel and a vertical transform kernel, and
the horizontal transform kernel and the vertical transform kernel of the transform kernel of the current block are determined based on a size of the current block, whether inter prediction is used for the prediction for the current block or not and whether intra prediction is used for the prediction for the current block or not.

### Claim 2 (depends on 1)

The image encoding method of claim 1, wherein the transform kernel information is index information indicating at least one of the predefined transform kernel sets.

### Claim 3 (depends on 1)

The image encoding method of claim 1, wherein the transform kernel information is encoded for each of coding units.

### Claim 4 (depends on 1)

The image encoding method of claim 1, wherein the transform kernel information is encoded when the size of the current block is less than or equal to a predefined size.

### Claim 5 (depends on 1)

The image encoding method of claim 1, wherein the transform kernel information is encoded when a non-zero transform coefficient exists in the current block.

### Claim 6 (depends on 1)

The image encoding method of claim 1, wherein the transform kernel information is encoded when a transform skip mode is not performed on the current block.

### Claim 7 (depends on 1)

The image encoding method of claim 1, wherein the horizontal transform kernel and the vertical transform kernel are determined independently.

### Claim 8

An image decoding method, comprising:
decoding transform kernel information for a current block and at least one coefficient of the current block from a bitstream;
determining a transform kernel of the current block based on the transform kernel information; and
performing a transform on the at least one coefficient of the current block, based on the transform kernel to generate residual samples,
wherein prediction for the current block using a prediction mode for the current block is performed,
the transform comprises a primary transform and a secondary transform,
the residual samples are generated by performing the primary transform using the transform kernel of the current block on a result of the secondary transform on the at least one coefficient,
the transform kernel information indicates one of predefined transform kernel sets as the transform kernel of the current block,
each of the predefined transform kernel sets comprises a predefined horizontal transform kernel and a predefined vertical transform kernel,
the transform kernel of the current block comprises a horizontal transform kernel and a vertical transform kernel, and
the horizontal transform kernel and the vertical transform kernel of the transform kernel of the current block are determined based on a size of the current block, whether inter prediction is used for the prediction for the current block or not and whether intra prediction is used for the prediction for the current block or not.

### Claim 9 (depends on 8)

The image decoding method of claim 8, wherein the transform kernel information is index information indicating at least one of the predefined transform kernel sets.

### Claim 10 (depends on 8)

The image decoding method of claim 8, wherein the transform kernel information is decoded for each of coding units.

### Claim 11 (depends on 8)

The image decoding method of claim 8, wherein the transform kernel information is decoded when the size of the current block is less than or equal to a predefined size.

### Claim 12 (depends on 8)

The image decoding method of claim 8, wherein the transform kernel information is decoded when a non-zero transform coefficient exists in the current block.

### Claim 13 (depends on 8)

The image decoding method of claim 8, wherein the transform kernel information is decoded when a transform skip mode is not performed on the current block.

### Claim 14 (depends on 8)

The image decoding method of claim 8, wherein the horizontal transform kernel and the vertical transform kernel are determined independently.

### Claim 15

A non-transitory computer-recordable medium for storing a bitstream, the bitstream comprising:
transform kernel information for a current block; and
at least one coefficient of the current block, wherein
a transform kernel of the current block is determined based on the transform kernel information,
a transform on the at least one coefficient of the current block is performed based on the determined transform kernel to generate residual samples,
prediction for the current block using a prediction mode for the current block is performed,
the transform comprises a primary transform and a secondary transform,
the residual samples are generated by performing the primary transform using the transform kernel of the current block on a result of the secondary transform on the at least one coefficient,
the transform kernel information indicates one of predefined transform kernel sets as the transform kernel of the current block,
each of the predefined transform kernel sets comprises a predefined horizontal transform kernel and a predefined vertical transform kernel,
the transform kernel of the current block comprises a horizontal transform kernel and a vertical transform kernel, and
the horizontal transform kernel and the vertical transform kernel of the transform kernel of the current block are determined based on a size of the current block, whether inter prediction is used for the prediction for the current block or not and whether intra prediction is used for the prediction for the current block or not.

### Claim 16 (depends on 15)

The non-transitory computer-recordable medium of claim 15, wherein the transform kernel information is index information indicating at least one of the predefined transform kernel sets.

### Claim 17 (depends on 15)

The non-transitory computer-recordable medium of claim 15, wherein the transform kernel information is encoded for each of coding units.

### Claim 18 (depends on 15)

The non-transitory computer-recordable medium of claim 15, wherein the transform kernel information is encoded when the size of the current block is less than or equal to a predefined size.

### Claim 19 (depends on 15)

The non-transitory computer-recordable medium of claim 15, wherein the transform kernel information is encoded when a non-zero transform coefficient exists in the current block.

### Claim 20 (depends on 15)

The non-transitory computer-recordable medium of claim 15, wherein the transform kernel information is encoded when a transform skip mode is not performed on the current block.