Structured "truncated Golomb code" for context-based adaptive VLC

In this paper, we describe a structured variable length coding (VLC) based on Golomb code that generalize the current context-based adaptive variable length coding (CAVLC) in the emerging video coding standard H.264/AVC. The current CAVLC is characterized as unstructured VLC and uses extensive dedicated code tables. Lack of generality due to these code tables causes a problem of over-fitting or overlearning when we estimate a set of coding parameters. We propose a “compact” structured code based on Golomb code providing generality, extensibility, and low implementation complexity with only three parameters. Introduction of a simple truncation method enables to avoid reversed order code length and remove unused code space for finite set of symbols. Experimental results show its similar coding efficiency to current CAVLC while reducing the size of memories to store code tables and providing adaptability for various probability functions.