This demo shows ways to use constraints and statistics in WebRTC applications.
Set camera constraints, and click Get media to (re)open the camera with these included. Click Connect to create a (local) peer connection. The RTCPeerConnection objects localPeerConnection and remotePeerConnection can be inspected from the console.
Setting a value to zero will remove that constraint.
The lefthand video shows the output of getUserMedia(); on the right is the video after being passed through the peer connection. The transmission bitrate is displayed below the righthand video.