title: I want to attach Pre-Rolls to videos taken on android devices
body: <p>I'm using mp4parser and the videos need to be of the same kind. 
  I was thinking of using android's media codec to decode &amp; encode the preroll video to fit the same encoding output of the cameras  (front &amp; back)
  any suggestion on how this can be done (how to get specific device encoding params)? </p>