Comparison of a Low Bit Rate Speech Compression Algorithm with the MELP Standard for Fricatives and Stops

"In this paper we examine the fricatives and stops encoding of a very low bit rate speech compression algorithm, based on a mixed multiband excitation system. The algorithm incorporates several improvements over previously reported coders. One of them is the use of a specific modelling and synthesis strategy for fricatives and stops at 400 b/s. The codec, which operates at an average rate of 1.2 kb/s, is compared with the North American standard 2.4 kb/s MELP coder for sentences with a large concentration of fricatives and stops sounds. Subjective listening tests indicate that the two codecs are comparable for both types of sounds, although the sound specific scheme operates at 400 b/s, whilst the MELP operates at 2.4 kb/s."