Patent Document ID: 20160080742
Application ID: 14944012
Patent Status: 0

Claim One:
1. An apparatus for decoding a transform coefficient block, the apparatus comprising: a decoder configured to extract, from a data stream, a significance map indicating positions of significant transform coefficients within the transform coefficient block, and the significant transform coefficients within the transform coefficient block; and an associator configured to associate the extracted significant transform coefficients with their respective positions in the transform coefficient block in a coefficient scan order, wherein according to the coefficient scan order, sub-blocks of the transform coefficient block are scanned in a sub-block scan order, and the transform coefficients within each sub-block are scanned in a position sub-scan order, wherein the decoder is configured to use, in extracting the significant transform coefficients, context-adaptive entropy decoding, a selected set of contexts from a plurality sets of contexts, wherein, for each sub-block, the selected set of contexts is determined based on a statistic of the transform coefficients within a previously traversed sub-block of the transform coefficient block, or a statistic of the transform coefficients of a co-located sub-block in a previously decoded transform coefficient block.