Test code:
var b:Bytes = Assets.getBytes("sfx/track1.mp3");
var data:MP3_DATA = {
bytes:b,
size:b.length
};
Mp3.decode(data);
var buffer:BytesBuffer = new BytesBuffer();
for(value in data.pcm){
buffer.addInt32(value);
}
var audioBuf = new AudioBuffer();
audioBuf.bitsPerSample = 16;
audioBuf.channels = data.channels;
audioBuf.data = new UInt8Array(buffer.getBytes());
audioBuf.sampleRate = data.sampleRate;
var source:AudioSource = new AudioSource(audioBuf);
source.play();