# US 12,010,312 B2 · Method and device for encoding/decoding images

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- Number: US 12,010,312 B2
- Document ID: US12010312B2
- Status: Granted
- Kind: B2
- Application number: 18/160,976
- Filed: 2023-01-27
- Published: 2023-06-22
- Granted: 2024-06-11
- Earliest claimed: 2012-06-29
- Assignees: Electronics and Telecommunications Research Institute; University-Industry Cooperation Group of Kyung Hee University
- Applicants: Electronics and Telecommunications Research Institute; University-Industry Cooperation Group of Kyung Hee University
- Inventors: Hui Yong Kim; Sung Chang Lim; Jin Ho Lee; Jin Soo Choi; Jin Woong Kim; Gwang Hoon Park; Kyung Yong Kim
- Web page: https://patentgrep.com/patent/US12010312B2

## CPC

- H04N 19/12: Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
- H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
- H04N 19/124: Quantisation
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/593: involving spatial prediction techniques
- H04N 19/61: in combination with predictive coding
- H04N 19/625: using discrete cosine transform [DCT]
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method and a device for encoding/decoding images are disclosed. The method for encoding images comprises the steps of: deriving a scan type of a residual signal for a current block according to whether or not the current block is a transform skip block; and applying the scan type to the residual signal for the current block, wherein the transform skip block is a block to which transform for the current block is not applied and is specified on the basis of information indicating whether or not transform for the current block is to be applied.

## Claims

### Claim 1

A video decoding method, comprising:
obtaining first information indicating whether a residual signal is present in a current block;
determining a transform type of the current block, based on second information indicating whether or not an inverse-transform based on discrete cosine transform (DCT) or discrete sine transform (DST) is allowed;
acquiring transform coefficients from the residual signal of the current block based on a scanning direction for the residual signal of the current block, if the first information indicates that the residual signal is present in the current block;
performing the inverse-transform on the transform coefficients based on the determined transform type to obtain residual samples;
obtaining prediction samples of the current block based on an intra prediction mode of the current block; and
reconstructing the current block based on the residual samples and the prediction samples,
wherein the scanning direction is determined based on the second information.

### Claim 2 (depends on 1)

The video decoding method of claim 1, wherein the scanning direction is determined based on the intra prediction mode of the current block, if the second information indicates that the inverse-transform based on DCT or DST is allowed.

### Claim 3 (depends on 2)

The video decoding method of claim 2, wherein the scanning direction is determined independently to the intra prediction mode of the current block, if the second information indicates that the inverse-transform based on DCT or DST is not allowed.

### Claim 4 (depends on 1)

The video decoding method of claim 1, wherein the scanning direction is determined to be one of a first direction, a second direction and a third direction, based on the intra prediction mode of the current block, if the second information indicates that the inverse-transform based on DCT or DST is allowed.

### Claim 5 (depends on 4)

The video decoding method of claim 4, wherein the second direction is a direction of columns of the current block, and the third direction is a direction of rows of the current block.

### Claim 6 (depends on 5)

The video decoding method of claim 5, wherein the scanning direction is determined to be the first direction, independently to the intra prediction mode of the current block, if the second information indicates that the inverse-transform based on the DCT or the DST is not allowed.

### Claim 7 (depends on 6)

The video decoding method of claim 6, wherein the second direction is more vertical than the first direction, and the third direction is more horizontal than the first direction.

### Claim 8 (depends on 1)

The video decoding method of claim 1, wherein the transform type of the current block is determined further based on a size of the current block.

### Claim 9

A video encoding method, comprising:
performing an intra prediction based on an intra prediction mode of a current block to generate prediction samples for the current block;
determining whether a residual signal is present in a current block;
generating residual samples based on the prediction samples;
determining a transform type of the current block, based on whether or not an inverse-transform based on discrete cosine transform (DCT) or discrete sine transform (DST) is allowed;
transforming the residual samples based on the transform type of the current block to generate transform coefficients;
applying a scanning direction to the transform coefficients;
generating a bitstream comprising the residual signal if the residual signal is present in the current block,
wherein the scanning direction is determined based on whether or not an inverse-transform based on discrete cosine transform (DCT) or discrete sine transform (DST) is allowed.

### Claim 10

A non-transitory computer-readable recording medium storing a bitstream which is decoded by a decoding method, the video decoding method comprising:
obtaining first information indicating whether a residual signal is present in a current block;
determining a transform type of the current block, based on second information indicating whether or not an inverse-transform based on discrete cosine transform (DCT) or discrete sine transform (DST) is allowed;
acquiring transform coefficients from the residual signal of the current block based on a scanning direction for the residual signal of the current block, if the first information indicates that the residual signal is present in the current block;
performing the inverse-transform on the transform coefficients based on the determined transform type to obtain residual samples;
obtaining prediction samples of the current block based on an intra prediction mode of the current block; and
reconstructing the current block based on the residual samples and the prediction samples,
wherein the scanning direction is determined based on the second information.