MP4-SA is the sound of the future. Instead of describing recorded audio data, it notates the audio itself, making for radically smaller files and perfectly recreated sound. Old news maybe, but looking more and more relevant in these hard times of clogged university servers and bandwidth problems across the net.Streaming CD-quality audio can be transmitted through an average modem using Structured Audio (SA) part of the new MPEG-4 Audio standard. The standard differs from other audio file formats such as the now ubiquitous MP3, RA and WAV formats in a fairly fundamental way: instead of describing the recorded audio data, it describes the music-making process itself? the instruments and effects and mixing console that were used, the notes played, and the slider and knob movements. By following these descriptions precisely, it?s possible for a computer to perfectly recreate the audio intended by the composer.Sounds like MIDI, we hear you cry. Well, yes and no. Where MIDI has a tendency to sound diffeent on different machines, MPEG 4 Structured Audio gets around the problem by incorporating sound patches with the file that is transmitted. Thus the same MP4 file will sound the same even on machines with different MIDI patches. This does mean that MP4 files will be much bigger the MIDI files, but files are streamed so that MP4 can be played before it is fully downloaded. Files created by the SA process are extremely small compared to sizes of current audio formats (SA files will be around 3 kilobyte for a 1 minute interactive, interesting and complex performance!). And because of the way Structured Audio is organized, it’s possible to make the music interactive, responding (for instance) to the moods of the characters or the scenario in a computer game.MIT’s MP4 page
More on Structured Audio
MIT’s Netsound Project.... But you’ll need an SGI to hear anything. Doh.
