CodeSimian uses JLayer to decompress MP3 files.

CodeSimian has its own sound-playing abilities
and synthesized sounds from code long before JLayer was added.

The way JLayer is accessed is by any of 3 simple codes,
typed into CodeSimian, usually in combination with other codes:
mp3(fileNameOrURL)
or
mp3(fileNameOrURL decimalPosition)
or
mp3(fileNameOrURL decimalPosition megabyteLimit)

Every time you execute that command, it returns the audio data (range -1 to 1)
in the mp3 at a specific number position, 1 number for each audio sample in the mp3,
usually 22050 of them per second, but you can execute it at any speed you want,
stop for as long as you want, reposition... you have complete control
over the position and therefore the speed.
It interpolates if you ask for a non-integer (decimal) position.

For example, the Codesimian code: sound(mp3('http://codesimian.com/a.mp3' *(-3.4 count) 5))
downloads that MP3 then plays it backwards at 3.4x speed and stops decompressing
after the total decompressed data is 5 megabytes (about 30 seconds of audio).
Or sound(mp3('http://codesimian.com/a.mp3')) downloads and plays with default options.

Currently (9/06) JLayer gets the mp3 audio data,
but CodeSimian determines how and when to play it through the sound card and speakers.