I recently wanted to listen to some music files using Spotify and discovered it does not deal with Apple’s proprietary m4a format. I hunted around for an easy way to convert the 700+ m4a files I’ve acquired to mp3 format. There seem to be several GUI programs, mostly that run on Windows. However, being a command-line type of person, and not running Windows, I saught a different solution.

http://wiki.tamaratemple.com/Technology/ConvertM4AfilesToMP3UsingFfmpeg describes the method I found to do this with the ffmpeg program on *nix systems (Linux, BSD, OS/X). It may work on windows, but I couldn’t say. Enjoy.