| 摘要 |
The invention relates to a method of variable length coding in which data symbols are arranged into a number of sets, each of which comprises at least a first data symbol. At least two sets of variable length codewords are provided for variable length coding the data symbols and the sets of data symbols are variable length coded in a coding sequence, starting from a first set and progressing to a last set of data symbols. For a given set of data symbols, other than the first set of data symbols in the coding sequence, a set of cumulative information measures is determined, each of which is representative of a total amount of information required to variable length code the first data symbols of all the sets of data symbols preceding the given set of data symbols in the coding sequence using a predetermined one of the at least two sets of variable length codewords. The set of cumulative information measures is examined to determine which of the at least two sets of variable length codewords provides the smallest cumulative information measure and a codeword is selected to variable length code the first data symbol of the given set of data symbols from the set of variable length codewords which provides the smallest cumulative information measure. A corresponding encoder, decoding method and decoder are also described.
|
