github twilio/twilio-video.js 2.0.0-beta14

2.0.0-beta14 (September 17, 2019)

New Features

  • In a Group Room, you can now control how your available downlink bandwidth is distributed among the RemoteVideoTracks that you have subscribed to. twilio-video.js introduces the Bandwidth Profile APIs. Note that this feature is currently in private beta and hence will be opt-in. Please reach out to for more information about how to enable these APIs for your Twilio Account.

Using these APIs in a Peer-to-Peer Room will have no effect.

### Bandwidth Profile (private beta)

You can now configure how your available downlink bandwidth will be distributed among your subscribed RemoteVideoTracks by using a new optional ConnectOptions parameter bandwidthProfile. For more details, please refer to the BandwidthProfileOptions documentation. Here is an example:

  const { connect } = require('twilio-video');
  const room = await connect(token, {
    bandwidthProfile: {
      video: {
        dominantSpeakerPriority: 'high', // Min. subscribe priority of Dominant Speaker's RemoteVideoTracks.
        maxSubscriptionBitrate: 150000, // Max. bandwidth (bps) to be allocated to subscribed RemoteVideoTracks.
        maxTracks: 3, // Max. number of visible RemoteVideoTracks. Other RemoteVideoTracks will be switched off.
        mode: 'collaboration', // Subscription mode: "collaboration", "grid" or "presentation".
        renderDimensions: {
          low: { // Desired render dimensions of RemoteVideoTracks with priority "low".
            width: 320,
            height: 240
          standard: { // Desired render dimensions of RemoteVideoTracks with priority "standard".
            width: 640,
            height: 480
          high: { // Desired render dimensions of RemoteVideoTracks with priority "high".
            width: 1080,
            height: 720

### Track Priority (private beta)

While publishing a LocalTrack, you can now optionally specify its publish priority in the following way:

  const localTrackPublication = await room.localParticipant.publishTrack(localTrack, {
    priority: 'high' // LocalTrack's publish priority - "low", "standard" or "high"

  // LocalTrackPublication has a new property "priority" which stores the publish
  // priority set while publishing the corresponding LocalTrack.
  assert.equal(localTrackPublication.priority, 'high');

This signals to the media server the relative importance of this LocalTrack with respect to other Tracks that may be published to the Room. The media server takes this into account while allocating a subscribing RemoteParticipant's bandwidth to the corresponding RemoteTrack. If you do not specify a priority, then it defaults to standard.

You can also find out about the priorities of RemoteTracks published by other RemoteParticipants by accessing a new property publishPriority on the corresponding RemoteTrackPublications:

  remoteParticipant.on('trackPublished', remoteTrackPublication => {
    console.log(`RemoteParticipant published a Track with priority ${remoteTrackPublication.publishPriority}`);

### Switching on/off RemoteVideoTracks (private beta)

When a subscribing Participant's downlink bandwidth is insufficient, the media server tries to preserve higher priority RemoteVideoTracks by switching off lower priority RemoteVideoTracks, which will stop receiving media until the media server decides to switch them back on. You can now get notified about these actions by listening to the switchedOff and switchedOn events on the RemoteVideoTrack:

  remoteTrackPublication.on('subscribed', remoteTrack => {
    remoteTrack.on('switchedOff', () => {
      // You can now determine whether a particular RemoteTrack is switched off.
      assert.equal(remoteTrack.isSwitchedOff, true);
      console.log(`The RemoteTrack ${} was switched off`);

    remoteTrack.on('switchedOn', () => {
      assert.equal(remoteTrack.isSwitchedOff, false);
      console.log(`The RemoteTrack ${} was switched on`);

Bug Fixes

  • Fixed a bug where LocalVideoTracks were being published at a very low bitrate even when there was sufficient bandwidth to publish at higher bitrates. (JSDK-2509)
latest releases: 2.14.0-rc1, 2.13.0, 2.13.0-rc5...
17 months ago