Configurable variable length code for video coding

Abstract

The variable length code (VLC) tables in MPEG-1/2/4 and H.263 are fixed and optimized for a limited range of bit-rates, and they cannot handle a variety of applications. The universal variable length code (UVLC) is a new scheme to encode syntax elements and has some configurable capabilities. It is also being considered in ITU-T H.26L. However, the configurable feature of the UVLC has not been well explored. We propose configuring the UVLC with the additional code configuration (ACC). The ACC is used to adapt UVLC to different symbol distributions by adjusting the partitioning of the symbols into different categories, and the code size assignment to different categories. Experimental results show that the UVLC with ACC outperforms the current proposed scheme in H.26L and the VLC tables of existing standards, while drastically simplifying the encoding and decoding process, and is applicable to a variety of applications.