Usage of Multi-Alphabet Arithmetic Codes for Multi-Symbol Source Coding

Abstract

Basic study is done for multi-symbol source coding using multi-alphabet arithmetic codes. We assumed the source model in which the probability of N-th probable symbol is given as R（0＜R≦1）times of that of (N-1)-th probable symbol. The arithmetic code register length is assumed to be 14 bit or more for 256 symbols. The assigned widths of the symbols other than the most probable symbol are fixed for variable valid area, and the rest of the valid area is assigned to the most probable symbol. The value of the valid area, at which the assigned widths of the symbols follow the information model, is defined in accordance with R, for the optimization of the coding efficiency, and the design example for two-divided valid areas is also shown. We pointed out the general learning issues for the adaptive coding.