title: SoX doesn't work with Opus Audio files
body: <p>I am recording input microphone from a web page with WebRTC and process it through SoX.</p>
  
  <p>Problem is, Firefox recordings are in Opus Audio format (according to VLC media informations), in an Ogg container, and SoX doesn't like it : 
  <code>/opt/local/bin/sox FAIL formats: can't open input file `/Users/[...]/public/audio/7a0d13a501.ogg': Input not an Ogg Vorbis audio stream
  </code></p>
  
  <p>Is there a way to make it work with SoX?
  Or should I use another command-line audio tool?</p>