Length-Limited Variable-to-Variable Length Codes For High-Performance Entropy Coding

Arithmetic coding achieves a superior coding rate when encoding a binary source, but its lack of speed makes it an inferior choice when true high? performance encoding is needed. We present our work on a practical implementation of fast entropy coders for binary messages utilizing only bit shifts and table lookups. To limit code table size we limit our code lengths with a type of variable?to?variable (VV) length code created from source string merging. We refer to these codes as "merged codes". With merged codes it is possible to achieve a desired level of speed by adjusting the number of bits read from the source at each step. The most efficient merged codes yield a coder with a worst?case inefficiency of 0.4%, relative to the Shannon entropy. Using a hybrid Golomb?VV Bin Coder we are able to achieve a compression ratio that is competitive with other state?of?the?art coders, at a superior throughput.

• Type: Conference
• Year: 2004
• Where: DCC
• Authors: Joshua G. Senecal, Mark A. Duchaineau, Kenneth I. Joy
• Keywords: Computer Graphics, DCC 2004, Efficient Merged Codes, Fast Entropy Coders, Merged Codes