i dunno where they are on builds now a days, i do know i flashed a new Rom and someof my album art that wasnt working b4, now works... so i assumed their was an updated version of WMP or something...
m4a, those are iTUnes files arent they??? sorry Anti-Apple here, just know that an EX used to send me songs and im pretty sure they were m4a, my stock rom never played em... if their iTunes then there digitally signed, you need to remove the DMR or whatever its called...
looks like Nitrogen plays m4a though.. check it out
http://forum.ppcgeeks.com/showthread...&highlight=m4a