TRANSFORM COEFFICIENT CODING

摘要

An idea used herein is to use the same function for the dependency of the context and the dependency of the symbolization parameter on previously coded/decoded transform coefficients. Using the same function—with varying function parameter—may even be used with respect to different transform block sizes and/or frequency portions of the transform blocks in case of the transform coefficients being spatially arranged in transform blocks. A further variant of this idea is to use the same function for the dependency of a symbolization parameter on previously coded/decoded transform coefficients for different sizes of the current transform coefficient's transform block, different information component types of the current transform coefficient's transform block and/or different frequency portions the current transform coefficient is located within the transform block.

主权项

1. An apparatus for decoding a plurality of transform coefficients comprising transform coefficient levels from a data stream, comprising
a context adaptive entropy decoder configured to, for a current transform coefficient, entropy decode a first set of one or more symbols from the data stream; a desymbolizer configured to map the first set of one or more symbols onto a transform coefficient level within a first level interval in accordance with a first symbolization scheme; an extractor configured to, if the transform coefficient level onto which the first set of one or more symbols is mapped in accordance with the first symbolization scheme is a maximum level of the first level interval, extract a second set of symbols from the data stream, wherein the desymbolizer is configured to map the second set of symbols onto a position within a second level interval in accordance with a second symbolization scheme which is parameterizable in accordance with a symbolization parameter, wherein the context adaptive entropy decoder is configured to, in entropy decoding at least one predetermined symbol of the first set of one or more symbols from the data stream, use a context depending, via a function parameterizable via a function parameter, with the function parameter set to a first setting, on previously decoded transform coefficients, and wherein the apparatus further comprises a symbolization parameter determinator configured to, if the transform coefficient level onto which the first set of one or more symbols is mapped in accordance with the first symbolization scheme is a maximum level of the first level interval, determine the symbolization parameter depending, via the function with the function parameter set to a second setting, on the previously decoded transform coefficients.