LiveKit Flutter SDK

Official Flutter SDK for LiveKit. Easily add real-time video and audio to your Flutter apps.

This package is published to pub.dev as livekit_client.

Docs

Docs and guides at https://docs.livekit.io

Installation

Include this package to your pubspec.yaml

...
dependencies:
  livekit_client: <version>

iOS

Camera and microphone usage need to be declared in your Info.plist file.

...
<dict>
  <key>NSCameraUsageDescription</key>
  <string>$(PRODUCT_NAME) uses your camera</string>
  <key>NSMicrophoneUsageDescription</key>
  <string>$(PRODUCT_NAME) uses your microphone</string>
</dict>

Android

We require a set of permissions that need to be declared in your AppManifest.xml. These are required by Flutter WebRTC, which we depend on.

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.your.package">
  <uses-feature android:name="android.hardware.camera" />
  <uses-feature android:name="android.hardware.camera.autofocus" />
  <uses-permission android:name="android.permission.CAMERA" />
  <uses-permission android:name="android.permission.RECORD_AUDIO" />
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
  <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
  <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
  ...
</manifest>

Example app

We built a multi-user conferencing app as an example in the example/ folder. You can join the same room from any supported LiveKit clients.

Usage

Connecting to a room, publish video & audio

var room = await LiveKitClient.connect(url, token);
try {
  // video will fail when running in ios simulator
  var localVideo = await LocalVideoTrack.createCameraTrack();
  await room.localParticipant.publishVideoTrack(localVideo);
} catch (e) {
  print('could not publish video: $e');
}

var localAudio = await LocalAudioTrack.createTrack();
await room.localParticipant.publishAudioTrack(localAudio);

Rendering video

Each track can be rendered separately with the provided VideoTrackRenderer widget.

VideoTrack? track;

@override
Widget build(BuildContext context) {
  if (track != null) {
    return VideoTrackRenderer(track);
  } else {
    return Container(
      color: Colors.grey,
    );
  }
}

Audio handling

Audio tracks are rendered automatically as long as you are subscribed to them.

Handling changes

LiveKit client makes it simple to build declarative UI that reacts to state changes. It notifies changes in two ways

  • ChangeNotifier - generic notification of changes
  • RoomDelegate and ParticipantDelegate - notification of specific events.

This example will show you how to use both to react to room events.

class RoomWidget extends StatefulWidget {
  final Room room;

  RoomWidget(this.room);

  @override
  State<StatefulWidget> createState() {
    return _RoomState();
  }
}

class _RoomState extends State<RoomWidget> with RoomDelegate {
  @override
  void initState() {
    super.initState();
    widget.room.delegate = this;
    widget.room.addListener(_onChange);
  }

  @override
  void dispose() {
    widget.room.delegate = null;
    super.dispose();
  }

  void _onChange() {
    // perform computations and then call setState
    // setState will trigger a build
    setState(() {
      // your updates here
    });
  }

  @override
  void onDisconnected() {
    // onDisconnected is a RoomDelegate method, handle when disconnected from room
  }

  @override
  Widget build(BuildContext context) {
    // your build function
  }
}

Similarly, you could do the same when rendering participants. Reacting to changes makes it possible to handle tracks published/unpublished or re-ordering participants in your UI.

class VideoView extends StatefulWidget {
  final Participant participant;

  VideoView(this.participant);

  @override
  State<StatefulWidget> createState() {
    return _VideoViewState();
  }
}

class _VideoViewState extends State<VideoView> with ParticipantDelegate {
  TrackPublication? videoPub;

  @override
  void initState() {
    super.initState();
    widget.participant.addListener(this._onParticipantChanged);
    // trigger initial change
    _onParticipantChanged();
  }

  @override
  void dispose() {
    widget.participant.removeListener(this._onParticipantChanged);
    super.dispose();
  }

  @override
  void didUpdateWidget(covariant VideoView oldWidget) {
    oldWidget.participant.removeListener(_onParticipantChanged);
    widget.participant.addListener(_onParticipantChanged);
    _onParticipantChanged();
    super.didUpdateWidget(oldWidget);
  }

  void _onParticipantChanged() {
    var subscribedVideos = widget.participant.videoTracks.values.where((pub) {
      return pub.kind == TrackType.VIDEO &&
          !pub.isScreenShare &&
          pub.subscribed;
    });

    setState(() {
      if (subscribedVideos.length > 0) {
        var videoPub = subscribedVideos.first;
        if (videoPub is RemoteTrackPublication) {
          videoPub.videoQuality = widget.quality;
        }
        // when muted, show placeholder
        if (!videoPub.muted) {
          this.videoPub = videoPub;
          return;
        }
      }
      this.videoPub = null;
    });
  }

  @override
  Widget build(BuildContext context) {
    var videoPub = this.videoPub;
    if (videoPub != null) {
      return VideoTrackRenderer(videoPub.track as VideoTrack);
    } else {
      return Container(
        color: Colors.grey,
      );
    }
  }
}

Mute, unmute local tracks

On LocalTrackPublications, you could control if the track is muted by setting its muted property. Changing the mute status will generate an onTrackMuted or onTrack Unmuted delegate call for the local participant. Other participant will receive the status change as well.

// mute track
trackPub.muted = true;

// unmute track
trackPub.muted = false;

Subscriber controls

When subscribing to remote tracks, the client has precise control over status of its subscriptions. You could subscribe or unsubscribe to a track, change its quality, or disabling the track temporarily.

These controls are accessible on the RemoteTrackPublication object.

For more info, see Subscriber controls.

License

Apache License 2.0

Thanks

A huge thank you to flutter-webrtc for making it possible to use WebRTC in Flutter.

Libraries

livekit_client
Flutter Client SDK to LiveKit.