You can do this directly in the Finder, starting with Mac OS X 10.7 (Lion), as described at [OSX Daily](http://osxdaily.com/2012/01/16/convert-video-to-audio-mac-os-x-lion/).

The short answer is, select the file or files in the Finder, then <kbd>ctrl</kbd>-click and choose **Services -> Encode Selected Video Files**. 

Note that you may need to [enable this service in the Keyboard preference pane](http://osxdaily.com/2012/01/16/enable-video-audio-encoder-in-mac-os-x/).

![enter image description here][1]


  [1]: https://i.sstatic.net/1hvYI.png