A SIMPLE VARIABLE-LENGTH CODE

This paper describes a Simple Variable-Length Code (SVLC) that is very efficient, typically within 1% of Huffman coding. Furthermore, it has very low overhead when the ordering of the probabilities is approximately monotonic, which is important for short messages. An inexpensive hardware implementation is described, and a software implementation is included. This paper presents two fast and intuitive algorithms for producing SVLC codes, and an algorithm that produces optimal codes. The fast algorithms are shown to be efficient for several distributions, and optimal when the probabilities are exponentially distributed. The complexities of the fast algorithms are O(K), and that of the optimal one is O(K log K), where K is the size of the symbol alphabet.