Huffman tree based metric derivation for a low-complexity sequential soft VLC decoding

This paper considers VLC decoding algorithms based on MAP sequence estimation techniques, using residual source redundancy to provide channel error correction. These algorithms rely on soft values available at the entrance of the VLC decoder. We present a new soft VLC decoding algorithm based on a sequential decoding technique that is very efficient in terms of decoding complexity. The application of the considered soft decoding algorithms to practical decoding of MPEG-4 texture information packets under the assumption of an unequal protection scheme is investigated. The algorithm performance is evaluated on the well-known "Foreman" video sequence. Simulation results show that the proposed algorithm provides approximately the same performance as all existing soft decoding algorithms while exhibiting a significantly lower complexity.