Efficient table access for reversible variable length code decoding using a hash function

摘要

An efficient decoding of reversible variable length codes of the type implemented for H.263++ and MPEG-4 DCT coefficients using lookup tables. Simple-profile MPEG-4 also has the option of using reversible variable length codewords (RVLC) that can be decoded in either the forward or backward direction, for error recovery. Because of the special structure of RVLC codewords, the decoding techniques for regular VLC are less efficient with RVLC. A new method for RVLC decoding is described.