I think Mugen plays the music files it basically has plugins for.

For some reason, stage mp3's play 99% of the time, whereas my title screen and character vs mp3's play 5% of the time...what gives?

Also is it true that mp3's work good or bad depending on the screen pack you have installed? GGX Heaven or Hell is shit when it comes to my mp3's playing. This problem does not exist with my other screenpacks and definitely not the default Mugen one.

As for my title screen and character vs (which do not work regardless of the screenpack) this is what I have in my Data -> system.def
__________

[Music]
 ;Put a filename for a MOD, MP3 or MIDI here, or just leave it
 ;blank if you do not want music. If an invalid filename is
 ;given, then no music will play. To play CD audio, put
 ;the track number followed by ".da". For example, to play
 ;track 3 from a music CD at the title screen, use:
 ;  title.bgm = 3.da
 ;To play mymusic.mp3 from the sound/ directory, put:
 ;  title.bgm = sound/mymusic.wma
 ;Music will continue to play between screens if the files names
 ;are the same, and both BGMs are specified to loop.
  ;Music to play at title screen.
title.bgm = BNW.wma
title.bgm.loop = 1        ;Set to 0 to prevent looping
  ;Music to play at char select screen.
select.bgm = Iron_blood.wma
select.bgm.loop = 0
  ;Music to play at versus screen.
vs.bgm =
vs.bgm.loop = 1
__________

Is there anything wrong? Plugins I have are in_mad.dll, in_adx.dll, in_mp3.dll, in_mp3pro.dll, in_psf.dll, in_qsf.dll, in_snes.dll, in_vorbis.dll, and libmad.dll

I also wonder if Mugen plays FLAC files...