HIGH-QUALITY AUDIO COMPRESSION USING AN ADAPTIVE WAVELET PACKET DECOMPOSITION AND PSYCHOACOUSTIC MODELING

This paper presents a technique to incorporate psychoacoustic models i nto an adaptive wavelet packet scheme to achieve perceptually transpar ent compression of high-quality (44.1 kHz) audio signals at about 45 k b/s, The filter bank structure adapts according to psychoacoustic crit eria and according to the computational complexity that is available a t the decoder, This permits software implementations that can perform according to the computational power available in order to achieve rea l time coding/decoding. The bit allocation scheme is an adapted zero-t ree algorithm that also takes input from the psychoacoustic model, The measure of performance is a quantity called subband perceptual rate, which the filter bank structure adapts to approach the perceptual entr opy (PE) as closely as possible. In addition, this method is also amen able to progressive transmission, that is, it can achieve the best qua lity of reconstruction possible considering the size of the bit stream available at the encoder, The result is a variable-rate compression s cheme for high-quality audio that takes into account the allowed compu tational complexity, the available bit-budget, and the psychoacoustic criteria for transparent coding, This paper thus provides a novel sche me to marry the results in wavelet packets and perceptual coding to co nstruct an algorithm that is well suited to high-quality audio transfe r for internet and storage applications.