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 prioritization is presented, An infinite impulse response (IIR) quadrature mirror filterbank (QMF) performs subband decomposition, A perceptual model, computed using subband spectral analysis, optimizes the coder's perceptual quality, Dynamic bit allocation and prioritization is combined with embedded quantization resulting in little performance degradation relative to a nonembedded implementation, The coder output is scalable from high quality at higher bit rates to lower quality at lower bit rates, supporting a wide range of service and resource utilization, The lower bit-rate representation is obtained simply through truncation of the higher bit-rate representation, Since source-rate adaptation is performed through truncation of the encoded stream, interaction with the coder is not required, making the embedded coder ideally suited for rate-adaptive communication systems, performance for both speech and music was verified through subjective listening tests.