Scalable embedded zero tree wavelet packet audio coding

Abstract

Multimedia transmission over the Internet is getting popular and increasingly important. In particular, scalable coding is desirable for a heterogeneous network with varied bandwidths. We propose a scalable embedded zero tree wavelet packet (scalable EZWP) audio coding system that is a scalable audio compression system using wavelet packet decomposition and embedded zero-tree coding. We focus on multilayer low-bitrate coding which delivers high perceptual quality. In the base layer, the overlapped audio segment is first transformed by the wavelet packet. Then the local significant coefficients are extracted, quantized, and coded by variable length coding. In the enhancement layer and the full band layer, the residual signal that is the difference between the original and the output of the previous layer is coded via EZW with a psychoacoustic model and arithmetic coding. The target bit rates for three layers are 16, 32, and 64 Kbit/s, respectively. The performance of the proposed coding system is only slightly inferior to MPEG-1 layer 3 at 64 Kbit/s while it provides bitrate scalability that is suitable for multimedia distribution over the Internet with heterogeneous networks.