Wavelet packet based scalable audio coding

Scalability, a well known concept in video coding, has only recently been introduced to audio coding. In this paper, a novel approach to a two-stage wavelet packet based scalable audio coding system is presented. Two different structures have been designed and implemented, one in the time-domain, and its dual in the wavelet-domain; these are compared with an MPEG based scalable codec. Results at different bit-rates are shown, while trade-offs and limitations together with future developments for further reduced bit-rates are discussed.