Its been asked before... by me even. Apparently, mp3 is copywritted and FSO is trying to be license free as much as possible. When someone suggests mp3, someone else invariably suggests ogg, which is licence-free and supperior to mp3 in some respects (surround-sound for example). The drawbacks at this point have been motivation, since most campaigns out there don't distribute too many music files, so it hasn't been that necessary. Also, switching to a higher compression audio format will cut into performance slightly (in decoding it on the fly). Thirdly, I've heard it said from some coders that its not the easiest thing to add support for, though another coder recently indicated that he might be up to the tast, though that was about a month ago and I've heard nothing since. Basically, its one of those things they might do eventually, but there are more crucial things on their platter at this point.