Mp2 and Mp3 can both contain an analog surround sound signal. Not digital mind you. If you put enough effort, you can keep the surroundsound data in the stereo audio, works better at higher data rates though, and the stereo with surround signal can then be read by what ever dolby gear you have, and it'll be interperated, and mixed into your speakers. I know a 224kbit Mp2 stream can carry an analog surround sound signle quiet effectivly. Mp3 can do it, technicly, never seen it done myself though. Anyway, Mp3 is just a minor adaptation of Mp2 in the first place.
Damn... Now I wonder what a 128kbit mp1 sounds like. *goes to find out*



