Lossless audio coding with MPEG-4 structured audio

MPEG-4 structured audio (SA) has been proposed as a flexible standard for generalized audio coding. Originating out of Netsound software developed at MIT SA is based on MIDI-synthesis of sound, but it is enriched with DSP algorithms so as to allow emulation of other types of coders designed for speech and audio signals. We have investigated the use of structured audio for lossless coding of audio signals, and have found that certain limitations of structured audio make implementations of lossless coders less straightforward than might be desired. In particular we have used SA to implement an MPEG-4 compliant version of the lossless audio coder AudioPaK. To implement and validate our new coder we used the software system Sfront, which translates MPEG-4 SA files into efficient C programs that render the audio signal.