Combine an FFmpeg powered back-end with VLC rendered previews, then add in file size estimation, a gorgeous user interface and make it entirely free. That is Adapter - the ultimate converter app for Mac and PC.
Free or Paid
Version Of macOS App Was Tested On
mac os sierra
this app is fully accessible, and easy to use
The app is fully accessible with VoiceOver and is easy to navigate and use.
i enjoy this app a lot, it helps you convert audio, or videos, so that you can add them as movies to iTunes. note: this app is also available for windows, and its free as well.