Dynamic UVLC codeword re-mapping with fixed re-association table for H.26L

The universal variable length-coding scheme in H.26L has nice features such as error resiliency and two-way decodability, however, it is less efficient than the Huffman coding. To improve the coding efficiency of UVLC, we propose to use dynamic codeword re-mapping that changes mapping between symbols and codewords in order to better accommodate the statistical characteristics of symbols as much as possible. Encoder and decoder use the same re-mapping table, so encoder need not send additional overhead to inform the re-mapping relationship. Simulation results show that the proposed method gives maximum 8% bit reduction in inter frame, and up to about 5% bit reduction in intra frame.