If you're looking for a free video and audio converter for Mac, Media Converter is what you need.
When you open Media Converter, there's simply one window to drag your file into, with a drop down menu so you can choose your output format. You can use it to rip audio from video (eg. MP4 to MP3), or between different audio and video formats. Media Converter supports an impressive range of formats, and if you can't find what you want, the chances are you will find a downloadable preset available here.
The preferences menu in Media Converter gives you extensive control over the app and how files are converted. This is where you can set bit rates, for example. This mix of good configuration within preferences and a super simple main interface make Media Converter ideal for most users.
Media Converter is a fantastic free audio and video converter, that's both easy to use and flexible