title: what is the minimum resolution we can set for webrtc video?
body: <p>I am testing a peer to peer video chat app using webrtc. when I set the video contraints as</p>
  
  <pre><code>var video_constraints = {
      mandatory: {
          maxHeight: 120,
          maxWidth: 160 
      },
      optional: []
  };
  
  window.navigator.webkitGetUserMedia({
      audio: true,
      video: video_constraints
  }, onSuccess, onError);
  </code></pre>
  
  <p>this fires onError. what could be the reason?</p>