webrtchacks-example-global-stream.js

/**
 * Illustrates how to clone and manipulate MediaStream objects.
 */

function makeAudioOnlyStreamFromExistingStream(stream) {
  var audioStream = stream.clone();
  var videoTracks = audioStream.getVideoTracks();
  for (var i = 0, len = videoTracks.length; i < len; i++) {
    audioStream.removeTrack(videoTracks[i]);
  }
  console.log('created audio only stream, original stream tracks: ', stream.getTracks());
  console.log('created audio only stream, new stream tracks: ', audioStream.getTracks());
  return audioStream;
}

function makeVideoOnlyStreamFromExistingStream(stream) {
  var videoStream = stream.clone();
  var audioTracks = videoStream.getAudioTracks();
  for (var i = 0, len = audioTracks.length; i < len; i++) {
    videoStream.removeTrack(audioTracks[i]);
  }
  console.log('created video only stream, original stream tracks: ', stream.getTracks());
  console.log('created video only stream, new stream tracks: ', videoStream.getTracks());
  return videoStream;
}
function handleSuccess(stream) {
  var audioOnlyStream = makeAudioOnlyStreamFromExistingStream(stream);
  var videoOnlyStream = makeVideoOnlyStreamFromExistingStream(stream);
  // Do stuff with all the streams...
}
function handleError(error) {
  console.error('getUserMedia() error: ', error);
}
var constraints = {
  audio: true,
  video: true,
};
navigator.mediaDevices.getUserMedia(constraints).
    then(handleSuccess).catch(handleError);

makeAudioOnlyStreamFromExistingStream should work as new MediaStream(stream.getAudioTracks() which is better than cloning