How do I call without a MediaStream?

I have a use-case where:

• there are two people, Presenter and Viewer
• Presenter opens the page and gets a peer ID
• Presenter sends that peer ID to Viewer
• Viewer uses that peer ID to call Presenter
• Presenter sends his shared screen to the viewer

For this use-case I need, for the Viewer side:

var call = peer.call(presenterPeerID, null);
call.on('stream', function(theirWebcamStream) {
  showWebcamStream(theirWebcamStream);
});

This does not work, because peer.call(presenterPeerID, null) returns undefined.

How do I call without sending a MediaStream?

[afrokick]

You can create empty stream with any track, or with both:

export const createEmptyAudioTrack = () => {
  const ctx = new AudioContext();
  const oscillator = ctx.createOscillator();
  const dst = oscillator.connect(ctx.createMediaStreamDestination());
  oscillator.start();
  const track = dst.stream.getAudioTracks()[0];
  return Object.assign(track, { enabled: false });
};

export const createEmptyVideoTrack = ({ width, height }) => {
  const canvas = Object.assign(document.createElement('canvas'), { width, height });
  canvas.getContext('2d').fillRect(0, 0, width, height);

  const stream = canvas.captureStream();
  const track = stream.getVideoTracks()[0];

  return Object.assign(track, { enabled: false });
};

...

const audioTrack = createEmptyAudioTrack();
const videoTrack = createEmptyVideoTrack({ width:640, height:480 });
const mediaStream = new MediaStream([audioTrack, videoTrack]);

peer.call('id', mediaStream);

[mahmed0715]

+1