# US 7,411,526 B2 · Variable length coding method and variable length decoding method

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- Number: US 7,411,526 B2
- Document ID: US7411526B2
- Status: Granted
- Kind: B2
- Application number: 11/495,601
- Filed: 2006-07-31
- Published: 2006-11-23
- Granted: 2008-08-12
- Earliest claimed: 2001-11-22
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Shinya Kadono; Satoshi Kondo; Makoto Hagai; Kiyofumi Abe
- Web page: https://patentgrep.com/patent/US7411526B2

## CPC

- G06T 9/005: {Statistical coding, e.g. Huffman, run length coding}
- G11B 20/1426: {conversion to or from block codes or representations thereof}
- H03M 5/145: {Conversion to or from block codes or representations thereof}
- H03M 7/40: Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code
- H03M 7/46: Conversion to or from run-length codes, i.e. by representing the number of consecutive digits, or groups of digits, of the same kind by a code word and a digit indicative of that kind
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/134: characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/162: User input
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/60: using transform coding
- H04N 19/61: in combination with predictive coding
- H04N 19/69: involving reversible variable length codes [RVLC]
- H04N 19/89: involving methods or arrangements for detection of transmission errors at the decoder
- H04N 19/93: Run-length coding
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image coding apparatus provides a run-length encoding unit RLE1 that subjects quantized coefficients which are obtained by quantizing frequency components of an image signal to a variable length coding process by using a run value Run that indicates the number of successive zero coefficients and a level value Lev that indicates a value of a non-zero coefficient following the zero coefficients. The run-length encoding unit RLE1 includes a reordering unit Lreodr for reordering level values Lev; a variable length coder LVLC for coding reordered level values ROLev by using a code table that is selected according to the value of a quantization parameter QP; a reordering unit Rreodr for reordering run values Run from high frequency component of the quantized coefficients to low frequency component; and a variable length coder RVLC for coding reordered run values RORun by using a code table that is selected according to the number of already-processed run values.

## Claims

### Claim 1

A method for decoding a coded block image, the method comprising:
decoding coded transform coefficients from a high frequency component toward a low frequency component, in accordance with information that represents a total number of undecoded transform coefficients, to obtain decoded transform coefficients, wherein the undecoded transform coefficients are transform coefficients which have not been decoded;
inverse scanning the decoded transform coefficients into a two-dimensional array of transform coefficients; and
inverse quantizing and inverse frequency transforming the two-dimensional array of transform coefficients to obtain a reconstructed block image.