What kind of files can I edit?

If Media Center can play it, Media Editor can edit it. This includes APE, MP3, OGG, WAV, WMA, and MPC files.

Media Editor cannot be used to edit videos, DVD, TV, or those files that require RealPlayer for playback (LQT, RA, RAM, RM, RMJ, RMM, RMX, RP, RV, AA and VIV files).