A PERCEPTUALLY BASED EMBEDDED SUBBAND SPEECH CODER

A new scheme for robust, high-quality, embedded speech coding based on subband decomposition and perceptually optimized bit allocation and p rioritization is presented, An infinite impulse response (IIR) quadrat ure mirror filterbank (QMF) performs subband decomposition, A perceptu al model, computed using subband spectral analysis, optimizes the code r's perceptual quality, Dynamic bit allocation and prioritization is c ombined with embedded quantization resulting in little performance deg radation relative to a nonembedded implementation, The coder output is scalable from high quality at higher bit rates to lower quality at lo wer bit rates, supporting a wide range of service and resource utiliza tion, The lower bit-rate representation is obtained simply through tru ncation of the higher bit-rate representation, Since source-rate adapt ation is performed through truncation of the encoded stream, interacti on with the coder is not required, making the embedded coder ideally s uited for rate-adaptive communication systems, performance for both sp eech and music was verified through subjective listening tests.