It's recommended to only use uncompressed WAV audio files for editing. According to the comments posted
here, MP3s with a high enough bitrate (320kbps) should work as well as WAV files. I've never tried importing other types of audio files (.mpa, .mp4, .ogg, .flac, etc.) in WMM, so I don't know what happens if you try.
If the audio isn't WAV, you'll probably have to convert it first.
http://www.animemusicvideos.org/guides/ ... dio3c.html