$D$-semifaithful codes that are universal over both memoryless sources and distortion measures

Abstract

We prove the existence of codebooks for d-semifaithful lossy compression that are simultaneously universal with respect to both the class of finite-alphabet memoryless sources and the class of all bounded additive distortion measures. By applying independent random selection of the codewords according to a mixture of all memoryless sources, we achieve redundancy rates that are within O(log n/n) close to the empirical rate-distortion function of every given source vector with respect to every bounded distortion measure. As outlined in the last section, the principal ideas can also be extended significantly beyond the class of memoryless sources, namely, to the setting of individual sequences encoded by finite-state machines.