Probability updating-based adaptive hybrid coding (PUAHC)
Shilin Xu, Guangxi Zhu, Li Chen Yu, Chunhui Cui · 2006
Conventional entropy coding such as UVLC (universal variable length coding) usually uses variable length coding (VLC) based on static codeword table mechanism to code syntax elements which are partitioned from motion vectors and residual coefficients. UVLC employs half-variable length code (HVLC) such as kth order Exp-Golomb-Rice code to code syntax elements. However, static tables which indicate the average probability can not adapt the real-time probability distribution satisfactorily, so there are some needs to construct a probability updating mechanism in the codeword tables. If the real-time probability could be evaluated, Huffman code is undoubtedly the best choice for its approximation to source entropy. In PUAHC, dynamic Huffman code which is based on probability updating and Golomb code are joined together to code different source information for their adaptations to different kinds of probability distributions. In the experiment, it is proved that when PUAHC is used, the bit rate can be decreased by 3.9% and the computational complexity of decoder is also acceptable compared to UVLC