# US 9,438,933 B2 · Method and device for arithmetic coding of video, and method and device for arithmetic decoding of video

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- Number: US 9,438,933 B2
- Document ID: US9438933B2
- Status: Granted
- Kind: B2
- Application number: 14/635,545
- Filed: 2015-03-02
- Published: 2015-06-18
- Granted: 2016-09-06
- Earliest claimed: 2011-11-08
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Il-koo Kim; Jeong-hoon Park
- Web page: https://patentgrep.com/patent/US9438933B2

## CPC

- H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/1887: {the unit being a variable length codeword}
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/61: in combination with predictive coding
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Methods and apparatuses for arithmetic encoding/decoding of video data. The arithmetic decoding method includes arithmetically decoding prefix bit strings representing a two-dimensional location of a last significant coefficient in a block sequentially by using a context model, arithmetically decoding suffix bit strings in a bypass mode, and performing inverse binarization on the arithmetically decoded prefix bit strings and suffix bit strings to acquire the location of the last significant coefficient in the block.

## Claims

### Claim 1

A method for decoding a video, the method comprising:
obtaining an x coordinate prefix bitstring of a last significant coefficient in a transformation block by performing context-based-arithmetic decoding on a bitstream;
obtaining a y coordinate prefix bitstring of the last significant coefficient by performing context-based-arithmetic decoding on the bitstream;
obtaining an x coordinate suffix bitstring of the last significant coefficient by performing bypass mode decoding on the bitstream;
obtaining a y coordinate suffix bitstring of the last significant coefficient by performing bypass mode decoding on the bitstream;
obtaining an inverse-binarized x coordinate prefix and an inverse-binarized y coordinate prefix by performing inverse binarization according to a truncated unary binarization method on the x coordinate prefix bitstring and the y coordinate prefix bitstring;
obtaining an inverse-binarized x coordinate suffix and an inverse-binarized y coordinate suffix by performing inverse binarization according to a fixed length binarization method on the x coordinate suffix bitstring and the y coordinate suffix bitstring;
reconstructing an x coordinate of the last significant coefficient based on the inverse-binarized x coordinate prefix and the inverse-binarized x coordinate suffix;
reconstructing a y coordinate of the last significant coefficient based on the inverse-binarized y coordinate prefix and the inverse-binarized y coordinate suffix;
obtaining, based on the x coordinate and the y coordinate of the last significant coefficient, significant maps of subsets having a predetermined size which are split from the transformation block in a reverse index order of the subsets; and
reconstructing transformation coefficients in the transformation block based on the significant maps,
wherein, after the x coordinate prefix bitstring and the y coordinate prefix bitstring are obtained via the context-based-arithmetic decoding, the x coordinate suffix bitstring and the y coordinate suffix bitstring are obtained via the bypass mode decoding.

### Claim 2 (depends on 1)

The method of claim 1, wherein the x coordinate indicates x-th column (where x is an integer equal to or greater than 0) in the transformation block, and
the y coordinate indicates y-th row (where y is an integer equal or greater than 0) in the transformation block.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
reconstructing residuals in the transformation block by performing inverse-quantization and inverse-transformation on the reconstructed transformation coefficients.

### Claim 4 (depends on 1)

The method of claim 1, wherein the last significant coefficient is a non-zero transformation coefficient scanned last in a scanning order among transformation coefficients in the transformation block.

### Claim 5 (depends on 1)

The method of claim 1, wherein an origin of the x coordinate and the y coordinate of the last significant coefficient is an upper-leftmost point of the transformation block.