Patent ID: 8824557
Filing Date: 2014-09-02
Classification: H04N

Abstract:
1. A block transform-based method of encoding a compressed bitstream containing digital media data, the method comprising: iteratively for each of a plurality of successive blocks in order: entropy encoding coefficient values at locations of a current one of the plurality of successive blocks according to a scan order; analyzing the statistical incidence of occurrence of non-zero-value coefficient values at the locations; updating a set of cumulative statistics of the occurrence of non-zero-value coefficients at the locations, the cumulative statistics accounting for the occurrence of non-zero-value coefficient values at the locations in each block previously encoded since a scan order was set to an initial order; and adapting the scan order according to said updated cumulative statistics, wherein the adapting comprises exchanging the scan order of a first location with the scan order of a second location if the cumulative statistics indicate a higher occurrence of non-zero coefficient values at the second location than at the first location and not exchanging the scan order of the first location with the scan order of the second location if the cumulative statistics indicate a lower occurrence of non-zero coefficient values at the second location than at the first location, wherein the scan order of the second location is adjacent to the scan order of the first location, and wherein the method further comprises performing no further changes to the scan order of the second location for the current block if the scan order of the first location is exchanged with the scan order of the second location.