Though Mac OS X from Lion onward includes built-in encoding tools to perform conversions of video to audio, you can also extract an audio track from a movie by using QuickTime Player. No downloads are necessary, no enabling any buried features, it’s a simple Export setting in QuickTime and you’ll wind up with the audio track as an .m4a file, here’s how:
- Open any compatible video with QuickTime Player
- Pull down the File menu and choose “Export”
- From the “Format” drop down menu, select “Audio Only” and click “Export”
Conversion is usually very fast though ultimately it will depend on the speed of your Mac and the size of the video file. If you’re ripping the audio from a 45 minute TED talk so you can listen to it on the iPhone, it will take quite a bit longer than extracting audio from a short video.