Patent ID: 9699467
Date: 2017-07-04
CPC Classifications: H04N

Claim:
1. An apparatus for decoding a significance map indicating positions of significant transform coefficients within a transform coefficient block from a data stream comprising: a decoder configured to extract a significance map indicating positions of significant transform coefficients within the transform coefficient block, and then the values of the significant transform coefficients within the transform coefficient block from a data stream, with, in extracting the significance map, sequentially extracting first-type syntax elements from the data stream by context-adaptive entropy decoding, the first-type syntax elements indicating, for associated positions within the transform coefficient block as to whether at the respective position a significant or insignificant transform coefficient is situated; and an associator configured to sequentially associate the sequentially extracted first-type syntax elements to the positions of the transform coefficient block in a scan order determined from among a plurality of scan orders, wherein the decoder is configured to use, in context-adaptively entropy decoding the first-type syntax elements, contexts which are individually selected for each of the first-type syntax elements based at least on the scan order and a number of positions at which, according to the previously-extracted first-type syntax elements, significant transform coefficients are situated, in a neighborhood of the position with which a current first-type syntax element is associated, wherein different contexts for the first-type syntax elements relate to different combinations of the scan order and the number of positions.