Sliding-Block and Random Source Coding with Constrained Size Reproduction Alphabets

Recent research has shown that nearly optimum ratedistortion function performance can be obtained in encoding memoryless continuous-amplitude sources using a constrained-size reproduction alphabet. In this paper, we use a four-letter reproduction alphabet in encoding the Gaussian and Laplacian sources with the squared-error distortion measure. We introduce a sliding-block code generator/decoder and perform extensive coding simulations at a rate of one bit/source symbol. The average distortions in those simulations are much below the optimum quantization distortion and, with much smaller search intensity, are about the same or lower than distortions reported previously in comparable research. The slidingblock code results are also compared to those of parallel random coding simulations with the same reproduction alphabet and rate.