Method and apparatus for encoding residual block, and method and apparatus for decoding residual block

• US 10,178,401 B2
• Filed: 02/11/2015
• Issued: 01/08/2019
• Est. Priority Date: 10/28/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Cheon, Min-su, Min, Jung-hye, Han, Woo-jin
• Primary Examiner(s): Mung, On S
• Application Number:
  US14/619,299
• Publication Number:
  US 20150156504A1
• Time in Patent Office: 1,427 Days
• Field of Search: 37524012, 37524025
• CPC Class Codes: H04N 19/109 among a plurality of temporal predictive coding modes
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/635 characterised by filter definition or implementation details
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/96 Tree coding, e.g. quad-tree coding

Abstract

A method of decoding including obtaining transformation coefficients of a sub residual block based on location information of a non-zero transformation coefficient and level information of the non-zero transformation coefficient obtained from a bitstream.

Claims

1. A method for decoding an image, the method comprising:

splitting the image into a plurality of maximum coding units;

hierarchically splitting a maximum coding unit among the plurality of maximum coding units into a plurality of coding units based on split information of a coding unit;

determining a transformation residual block from a coding unit among the plurality of coding units based on split information of the transformation residual block, wherein the transformation residual block includes a plurality of sub residual blocks;

obtaining, from a bitstream, a coded block flag indicating whether the transformation residual block includes at least one non-zero effective transformation coefficient;

when the coded block flag indicates that the transformation residual block includes at least one non-zero effective transformation coefficient, determining whether a current sub residual block is a left-upper residual block among a plurality of sub residual blocks in the transformation residual block;

when the current sub residual block is a left-upper sub residual block, obtaining transformation coefficients of the left-upper sub residual block based on a significance map indicating a location of a non-zero transformation coefficient in the first sub residual block and level information of the non-zero transformation coefficient in the first sub residual block obtained from the bitstream;

when the current sub residual block is not a left-upper sub residual block, obtaining, from the bitstream, an effective coefficient flag of the current sub residual block without considering an effective coefficient flag of another sub residual block, the effective coefficient flag of the current sub residual block indicating whether at least one non-zero effective transformation coefficient exists in the current sub residual block;

when the effective coefficient flag indicates that at least one non-zero transformation coefficient exists in the current sub residual block, obtaining transformation coefficients of the current sub residual block based on a significance map indicating a location of the non-zero transformation coefficient in the current sub residual block and level information of the non-zero transformation coefficient in the current sub residual block obtained from the bitstream;

when the effective coefficient flag indicates that the at least one non-zero effective transformation coefficient does not exist in the current sub residual block, determining the transformation coefficients of the current sub residual block as zero; and

performing inverse-transformation on the transformation residual block including the current sub residual block,

wherein;

the transformation coefficients of the current sub residual block are a subset of transformation coefficients of the transformation residual block,

the transformation coefficients of the current sub residual block are obtained after or before transformation coefficients of another sub residual block among the plurality of sub residual blocks in the transformation residual block,

wherein a level information of a non-zero transformation coefficient includes information regarding a sign and an absolute value of the non-zero transformation coefficient,

when the split information of the coding unit of a current depth indicates a split, the coding unit of the current depth is split into the plurality of coding units of the lower depth, independently from neighboring coding units,

when the split information of the coding unit of the current depth indicates a non-split, one or more transformation residual blocks including the transformation residual block are obtained from the coding unit of the current depth, and

wherein the current sub residual block is one of a plurality of sub residual blocks which have same size with each other and square-shape, and are included in the transformation residual block.