Rate adjustable speech coding by lattice quantization

We address speech coding architectures, suited for channels such as packetized networks. We adopt the analysis-by-synthesis paradigm. To achieve operability at a continuum of rates, all explicit perceptual filtering in the codebook search is eliminated, and quantization is performed with lattice quantizers. In this particular implementation, rate-distortion performance is improved by entropy coding of the lattice indices. The result is a competitive coder applicable to both speech and music, where subjective as well as objective performance scales well with the rate of the coder.