title: WebRTC -- can getUserMedia use local stream?
body: <p>I want to let WebRTC encoded and play h264(NAL) stream(local file).
  In the WebRTC tutorial, getUserMedia is use for get local camera connecting to the system,  I don`t know if the getUserMedia function support
  capture the local stream file like h264 stream.</p>
  
  <p>If it doesn't work that way, may be I should modify WebRTC source code(I'm studying it). 
  Here is the question, If i change WebRTC code, how can i integration the new code into browser? Made it a plugin?</p>