Entropy encoding and decoding scheme

An apparatus for decoding comprising: a symbol decoder configured to obtain, based on codewords from a data stream, a first sequence of source symbols and a second sequence of source symbols, wherein source symbols of the first and second sequences are related to level values of transform coefficients of a transform coefficient block, wherein the level values of transform coefficients are encoded into the data stream according to a scan order leading through the transform coefficients of the transform coefficient block, and the symbol decoder is configured to obtain a first source symbol of the first sequence using a Rice code and a second source symbol of the first sequence using an Exp-Golomb code; and a composer configured to: compose a sequence of syntax elements having a value range which is sub-divided into a plurality of disjoint portions including at least three portions by, for each syntax element: obtaining a set of source symbols from the first and second sequences based on a portion of the plurality of disjoint portions associated with the syntax element, and combining values of the source symbols of the set to determine the value of the syntax element; and adapt one or more limits between the plurality of disjoint portions according to previously obtained source symbols.

A method for decoding comprising: obtaining, based on codewords from a data stream, a first sequence of source symbols and a second sequence of source symbols, wherein source symbols of the first and second sequences are related to level values of transform coefficients of a transform coefficient block, wherein the level values of transform coefficients are encoded into the data stream according to a scan order leading through the transform coefficients of the transform coefficient block, and the obtaining includes obtaining a first source symbol of the first sequence using a Rice code and obtaining a second source symbol of the first sequence using an Exp-Golomb code; and composing a sequence of syntax elements having a value range which is sub-divided into a plurality of disjoint portions including at least three portions by, for each syntax element: obtaining a set of source symbols from the first and second sequences based on a portion of the plurality of disjoint portions associated with the syntax element, and combining values of the source symbols of the set to determine the value of the syntax element, wherein one or more limits between the plurality of disjoint portions are adapted according to one or more previously obtained source symbols.

An apparatus for encoding comprising: a decomposer configured to: receive a sequence of syntax elements having a value range which is sub-divided into a plurality of disjoint portions including at least three portions, wherein the sequence of syntax elements are related to level values of transform coefficients of a transform coefficient block and the level values of transform coefficients are encoded into the data stream according to a scan order leading through the transform coefficients of the transform coefficient block, and obtain a sequence of source symbols based on the sequence of syntax elements by decomposing each syntax element into a corresponding set of source symbols based on a portion of the plurality of disjoint portions associated with the syntax element, such that a combination of values of the source symbols of the set yields the value of the syntax element; and a sub-divider configured to: receive the sequence of source symbols, and sub-divide the sequence of source symbols into a first sequence of source symbols and a second sequence of source symbols, wherein a first source symbol of the first sequence is encoded using a Rice code and a second source symbol of the first sequence is encoded using an Exp-Golomb code, and wherein the decomposer is configured to adapt one or more limits between the plurality of disjoint portions according to one or more previously obtained source symbols.

A non-transitory computer-readable medium for storing video data, comprising: a data stream stored in the non-transitory computer-readable medium and comprising data associated with a first sequence of source symbols and a second sequence of source symbols, wherein the source symbols of the first and second sequences are related to level values of transform coefficients of a transform coefficient block, which are encoded into the data stream according to a scan order leading through the transform coefficients of the transform coefficient block, and the source symbols are obtained based on a sequence of syntax elements having a value range which is sub-divided into a plurality of disjoint portions including at least three portions by executing operations using a processor, the operations including: decomposing each syntax element into a corresponding set of source symbols based on a portion of the plurality of disjoint portions associated with the syntax element, such that a combination of values of the source symbols of the set yields the value of the syntax element, and adapting one or more limits between the plurality of disjoint portions according to one or more previously obtained source symbols, wherein a first source symbol of the first sequence is encoded using a Rice code and a second source symbol of the first sequence is encoded using an Exp-Golomb code.