# US 11,310,530 B2 · Decoding device, encoding device, and decoding method

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- Number: US 11,310,530 B2
- Document ID: US11310530B2
- Status: Granted
- Kind: B2
- Application number: 17/106,234
- Filed: 2020-11-30
- Published: 2021-03-18
- Granted: 2022-04-19
- Earliest claimed: 2011-11-04
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Sharp Kabushiki Kaisha
- Inventors: Tomohiro Ikai; Yukinobu Yasugi; Tomoyuki Yamamoto; Takeshi Tsukuba
- Web page: https://patentgrep.com/patent/US11310530B2

## CPC

- H04N 19/60: using transform coding
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/124: Quantisation
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
- H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence)
- 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 19/18: the unit being a set of transform coefficients
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
- H04N 19/172: the region being a picture, frame or field
- H04N 19/436: using parallelised computational arrangements
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The amount of processing is reduced with high coding efficiency maintained. There is provided an arithmetic decoding device including syntax decoding means for decoding each of at least a first syntax element and a second syntax element indicating a transform coefficient using arithmetic decoding with a context or arithmetic decoding without a context. The syntax decoding means performs decoding that at least includes not decoding the first syntax element and decoding the second syntax element using the arithmetic decoding without a context, and decoding the first syntax element using the arithmetic decoding with a context and decoding the second syntax element using the arithmetic decoding without a context.

## Claims

### Claim 1

A decoding device for decoding an encoded image, the decoding device comprising:
a context derivation circuitry that derives a context index for a coefficient absolute level flag syntax element specifying whether there is an absolute value of transform coefficient greater than 1 for a scanning position; and
a bit decoding circuitry that decodes a bin value of a coefficient absolute remaining syntax element by using a bypass decoding process that does not use a context index, wherein the coefficient absolute remaining syntax element is related to a value obtained by subtracting a predetermined value from an absolute value of a transform coefficient for a scanning position,
wherein:
the bit decoding circuitry decodes a bin value of the coefficient absolute level flag syntax element by using a arithmetic decoding process that uses the context index, in a case that a condition is true, and
the context derivation circuitry derives a context value being equal to a sum of an offset and the context index for the coefficient absolute level flag syntax element, wherein the context index is derived by adding a first fixed value and a value based on a color component to a minimum value of (i) a variable related to a transform coefficient and (ii) a second fixed value.

### Claim 2

A encoding device for encoding image data, the encoding device comprising:
a context derivation circuitry that derives a context index for a coefficient absolute level flag syntax element specifying whether there is an absolute value of transform coefficient greater than 1 for a scanning position; and
a bit encoding circuitry that encodes a bin value of a coefficient absolute remaining syntax element by using a bypass encoding process that does not use a context index, wherein the coefficient absolute remaining syntax element is related to a value obtained by subtracting a predetermined value from an absolute value of a transform coefficient for a scanning position,
wherein:
the bit encoding circuitry encodes a bin value of the coefficient absolute level flag syntax element by using a arithmetic encoding process that uses the context index, in a case that a condition is true, and
the context derivation circuitry derives a context value being equal to a sum of an offset and the context index for the coefficient absolute level flag syntax element, wherein the context index is derived by adding a first fixed value and a value based on a color component to a minimum value of (i) a variable related to a transform coefficient and (ii) a second fixed value.

### Claim 3

A decoding method for decoding an encoded image, the decoding method comprising:
deriving a context index for a coefficient absolute level flag syntax element specifying whether there is an absolute value of transform coefficient greater than 1 for a scanning position;
decoding a bin value of a coefficient absolute remaining syntax element by using a bypass decoding process that does not use a context index, wherein the coefficient absolute remaining syntax element is related to a value obtained by subtracting a predetermined value from an absolute value of a transform coefficient for a scanning position;
decoding a bin value of the coefficient absolute level flag syntax element by using a arithmetic decoding process that uses the context index, in a case that a condition is true; and
deriving a context value being equal to a sum of an offset and the context index for the coefficient absolute level flag syntax element, wherein the context index is derived by adding a first fixed value and a value based on a color component to a minimum value of (i) a variable related to a transform coefficient and (ii) a second fixed value.