While converting a video to another format, I found it necessary to split apart an MPEG-2 file into it’s separate audio and video parts: an MPEG-1 audio file (.m1a) and an MPEG-2 video file (.m2v). QuickTime can convert MPEG-2 to another format, but couldn’t do much with an MPEG-1 audio file. After some searching, I found a utility that happily converts .m1a to .aiff, MAD audio encoder.
From that site: “Mad is a high Quality Open-Source Audio encoder Library. It encodes mp3, mp2 and others to aiff or cdda and others. This is particulary interesting, if you want to edit a mpeg file in quicktime or import an mpeg into FCP or DVD-Studio.”