Entropy encoding and decoding scheme using VLC coding and pipe or entropy coding for high compression efficiency

Entropy decoding apparatus comprising

• a VLC decoder configured to codeword-wisely reconstruct source symbols of a first subsequence of source symbols from codewords of a first bitstream;
• a probability interval partitioning entropy or arithmetic decoder configured to reconstruct a second subsequence of source symbols;
• a composer configured to compose a sequence of syntax elements comprising a value range which is sub-divided into a sequence of N partitions from the first subsequence of source symbols and the second subsequence of source symbols by individually composing each syntax element from a respective number n of source symbols by, for each of at least a subgroup of the syntax elements, determining the respective number n of source symbols si with i=1 . . . n depending on as to which of the sequence of N partitions into which a value range of the respective syntax elements is sub-divided, a value z of the respective syntax elements falls into, by summing-up the values of the respective number of source symbols si from 1 to n as long as the value of si corresponds to a range of the ith partition so as to acquire the value of the syntax element z, wherein the composer is configured to retrieve all source symbols sx with x being member of a first subset of {1 . . . N} from the first subsequence and all source symbols sy with y being member of a second subset of {1 . . . N} being disjoint to the first subset, from the second subsequence.

A non-transitory computer readable medium including a computer program comprising a program code for performing, when running on a computer, an entropy coding method comprising:

• converting a sequence of syntax elements comprising a value range which is sub-divided into a sequence of N partitions into a sequence of source symbols by individually decomposing each of at least a subgroup of the syntax elements into a respective number n of source symbols si with i=1 . . . n, the respective number n of source symbols depending on as to which of the sequence of N partitions a value z of the respective syntax elements falls into, so that a sum of values of the respective number of source symbols si yields z, and, if n>1, for all i=1 . . . n−1, the value of si corresponds to a range of the ith partition;
• subdividing the sequence of source symbols into a first subsequence of source symbols and a second subsequence of source symbols such that all source symbols sx with x being member of a first subset of {1 . . . N} are comprised within the first subsequence and all source symbols sy with y being member of a second subset of {1 . . . N} being disjoint to the first subset, are comprised within the second subsequence;
• by VLC encoding, symbol-wisely encoding the source symbols of the first subsequence;
• and
• by probability interval partitioning entropy or arithmetic encoding, encoding the second subsequence of source symbols.

A non-transitory computer readable medium including a computer program comprising a program code for performing, when running on a computer, an entropy decoding method comprising:

• by VLC decoding, codeword-wisely reconstructing source symbols of a first subsequence of source symbols from codewords of a first bitstream;
• by probability interval partitioning entropy or arithmetic decoding, reconstructing a second subsequence of source symbols;
• composing a sequence of syntax elements comprising a value range which is sub-divided into a sequence of N partitions from the first subsequence of source symbols and the second subsequence of source symbols by individually composing each syntax element from a respective number n of source symbols by, for each of at least a subgroup of the syntax elements, determining the respective number n of source symbols si with i=1 . . . n depending on as to which of the sequence of N partitions into which a value range of the respective syntax elements is sub-divided, a value z of the respective syntax elements falls into, by summing-up the values of the respective number of source symbols si from 1 to n as long as the value of si corresponds to a range of the ith partition so as to acquire the value of the syntax element z, wherein the composing comprises retrieving all source symbols sx with x being member of a first subset of {1 . . . N} from the first subsequence and all source symbols sy with y being member of a second subset of {1 . . . N} being disjoint to the first subset, from the second subsequence.