title: FFmpeg file conversion formats and file extensions
body: <p>I hope someone knows a link to point me to here. </p>
  
  <p>I'm converting different video and audio formats using ffmpeg. I want to only let files with file extensions be converted that are supported by ffmpeg. The supported formats are found here: <a href="http://ffmpeg.org/general.html#SEC4" rel="nofollow">http://ffmpeg.org/general.html#SEC4</a></p>
  
  <p>My question: is there a <strong>list of file extensions</strong> somewhere? I don't want to research for every format which file extensions might be used for that. Or is there a pain-free format-recognition library or class for C#/.NET available, that can scan for a audio/video format?</p>