twilio_programmable_video 0.9.0+2

Flutter plugin for Twilio Programmable Video, which enables you to build real-time videocall applications (WebRTC)

twilio_programmable_video

Flutter plugin for Twilio Programmable Video, which enables you to build real-time videocall applications (WebRTC)
This Flutter plugin is a community-maintained project for Twilio Programmable Video and not maintained by Twilio. If you have any issues, please file an issue instead of contacting support.

This package is currently work-in-progress and should not be used for production apps. We can't guarantee that the current API implementation will stay the same between versions, until we have reached v1.0.0.

Example

Check out our comprehensive example provided with this plugin.

Join the community

If you have any question or problems, please join us on Discord

FAQ

Read the Frequently Asked Questions first before creating a new issue.

Supported platforms

• Android
• iOS
• Web (not yet)

Getting started

Prerequisites

Before you can start using the plugin you need to make sure you have everything setup for your project.

Android

For this plugin to work for Android, you will have to tweak a few files.

Permissions

Open the AndroidManifest.xml file in your android/app/src/main directory and add the following device permissions:

...
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
...

Proguard

Add the following lines to your android/app/proguard-rules.pro file.

-keep class tvi.webrtc.** { *; }
-keep class com.twilio.video.** { *; }
-keep class com.twilio.common.** { *; }
-keepattributes InnerClasses

Also do not forget to reference this proguard-rules.pro in your android/app/build.gradle file.

android {

    ...

    buildTypes {

        release {

            ...    

            minifyEnabled true
            useProguard true

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

        }
    }
}

iOS

For this plugin to work for iOS, you will have to tweak a few files.

Permissions

Open the Info.plist file in your ios/Runner directory and add the following permissions:

...
<key>NSCameraUsageDescription</key>
<string>Your message to user when the camera is accessed for the first time</string>
<key>NSMicrophoneUsageDescription</key>
<string>Your message to user when the microphone is accessed for the first time</string>
<key>io.flutter.embedded_views_preview</key>
<true/>
...

Setting minimal iOS target to 11

1. In Xcode, open Runner.xcworkspace in your app's ios folder.
2. To view your app’s settings, select the Runner project in the Xcode project navigator. Then, in the main view sidebar, select the Runner target.
3. Select the General tab.
4. In the Deployment Info section, set the Target to iOS 11.

Background Modes

To allow a connection to a Room to be persisted while an application is running in the background, you must select the Audio, AirPlay, and Picture in Picture background mode from the Capabilities project settings page. See Twilio Docs for more information.

Connect to a Room

Call TwilioProgrammableVideo.connect() to connect to a Room in your Flutter application. Once connected, you can send and receive audio and video streams with other Participants who are connected to the Room.

Room _room;
final Completer<Room> _completer = Completer<Room>();

void _onConnected(Room room) {
  print('Connected to ${room.name}');
  _completer.complete(_room);
}

void _onConnectFailure(RoomConnectFailureEvent event) {
  print('Failed to connect to room ${event.room.name} with exception: ${event.exception}');
  _completer.completeError(event.exception);
}
  
Future<Room> connectToRoom() async {
  var connectOptions = ConnectOptions(
    accessToken,
    roomName: roomName,                   // Optional name for the room
    region: region,                       // Optional region.
    preferredAudioCodecs: [OpusCodec()],  // Optional list of preferred AudioCodecs
    preferredVideoCodecs: [H264Codec()],  // Optional list of preferred VideoCodecs.
    audioTracks: [LocalAudioTrack(true)], // Optional list of audio tracks.
    dataTracks: [
      LocalDataTrack(
        DataTrackOptions(
          ordered: ordered,                      // Optional, Ordered transmission of messages. Default is `true`.
          maxPacketLifeTime: maxPacketLifeTime,  // Optional, Maximum retransmit time in milliseconds. Default is [DataTrackOptions.defaultMaxPacketLifeTime]
          maxRetransmits: maxRetransmits,        // Optional, Maximum number of retransmitted messages. Default is [DataTrackOptions.defaultMaxRetransmits]
          name: name                             // Optional
        ),                                // Optional
      ),
    ],                                    // Optional list of data tracks   
    videoTracks: ([LocalVideoTrack(true, CameraCapturer(CameraSource.FRONT_CAMERA))]), // Optional list of video tracks.
  );
  _room = await TwilioProgrammableVideo.connect(connectOptions);
  _room.onConnected.listen(_onConnected);
  _room.onConnectFailure.listen(_onConnectFailure);
  return _completer.future;
}

You must pass the Access Token when connecting to a Room.

Join a Room

If you'd like to join a Room you know already exists, you handle that exactly the same way as creating a room: just pass the Room name to the connect method. Once in a Room, you'll receive a RoomParticipantConnectedEvent for each Participant that successfully joins. Querying the room.remoteParticipants getter will return any existing Participants who have already joined the Room.

Room _room;
final Completer<Room> _completer = Completer<Room>();

void _onConnected(Room room) {
  print('Connected to ${room.name}');
  _completer.complete(_room);
}

void _onConnectFailure(RoomConnectFailureEvent event) {
  print('Failed to connect to room ${event.room.name} with exception: ${event.exception}');
  _completer.completeError(event.exception);
}
  
Future<Room> connectToRoom() async {
  var connectOptions = ConnectOptions(
    accessToken,
    roomName: roomName,
    region: region,                       // Optional region.
    preferAudioCodecs: [OpusCodec()],     // Optional list of preferred AudioCodecs
    preferVideoCodecs: [H264Codec()],     // Optional list of preferred VideoCodecs.
    audioTracks: [LocalAudioTrack(true)], // Optional list of audio tracks.
    dataTracks: [
      LocalDataTrack(
        DataTrackOptions(
          ordered: ordered,                      // Optional, Ordered transmission of messages. Default is `true`.
          maxPacketLifeTime: maxPacketLifeTime,  // Optional, Maximum retransmit time in milliseconds. Default is [DataTrackOptions.defaultMaxPacketLifeTime]
          maxRetransmits: maxRetransmits,        // Optional, Maximum number of retransmitted messages. Default is [DataTrackOptions.defaultMaxRetransmits]
          name: name                             // Optional
        ),                                // Optional
      ),
    ],                                    // Optional list of data tracks
    videoTracks([LocalVideoTrack(true, CameraCapturer(CameraSource.FRONT_CAMERA))]), // Optional list of video tracks. 
  );
  _room = await TwilioProgrammableVideo.connect(connectOptions);
  _room.onConnected.listen(_onConnected);
  _room.onConnectFailure.listen(_onConnectFailure);
  return _completer.future;
}

Set up local media

You can capture local media from your device's microphone or camera in the following ways:

// Create an audio track.
var localAudioTrack = LocalAudioTrack(true);

// A video track request an implementation of VideoCapturer.
var cameraCapturer = CameraCapturer(CameraSource.FRONT_CAMERA);

// Create a video track.
var localVideoTrack = LocalVideoTrack(true, cameraCapturer);

// Getting the local video track widget.
// This can only be called after the TwilioProgrammableVideo.connect() is called.
var widget = localVideoTrack.widget();

Connect as a publish-only Participant

It is currently not possible to connect as a publish-only participant.

Working with Remote Participants

Handle Connected Participants

When you join a Room, Participants may already be present. You can check for existing Participants when the Room.onConnected listener gets called by using the room.remoteParticipants getter.

// Connect to a room.
var room = await TwilioProgrammableVideo.connect(connectOptions);

room.onConnected((Room room) {
  print('Connected to ${room.name}');
});

room.onConnectFailure((RoomConnectFailureEvent event) {
    print('Failed connecting, exception: ${event.exception.message}');
});

room.onDisconnected((RoomDisconnectEvent event) {
  print('Disconnected from ${event.room.name}');
});

room.onRecordingStarted((Room room) {
  print('Recording started in ${room.name}');
});

room.onRecordingStopped((Room room) {
  print('Recording stopped in ${room.name}');
});

// ... Assume we have received the connected callback.

// After receiving the connected callback the LocalParticipant becomes available.
var localParticipant = room.localParticipant;
print('LocalParticipant ${room.localParticipant.identity}');

// Get the first participant from the room.
var remoteParticipant = room.remoteParticipants[0];
print('RemoteParticipant ${remoteParticipant.identity} is in the room');

Handle Participant Connection Events

When Participants connect to or disconnect from a Room that you're connected to, you'll be notified via an event listener. These events help your application keep track of the participants who join or leave a Room.

// Connect to a room.
var room = await TwilioProgrammableVideo.connect(connectOptions);

room.onParticipantConnected((RoomParticipantConnectedEvent event) {
  print('Participant ${event.remoteParticipant.identity} has joined the room');
});

room.onParticipantDisconnected((RoomParticipantDisconnectedEvent event) {
  print('Participant ${event.remoteParticipant.identity} has left the room');
});

Display a Remote Participant's Widget

To see the Video Tracks being sent by remote Participants, we need to add their widgets to the tree.

room.onParticipantConnected((RoomParticipantConnectedEvent roomEvent) {
  // We can respond when the Participant adds a VideoTrack by adding the widget to the tree.
  roomEvent.remoteParticipant.onVideoTrackSubscribed((RemoteVideoTrackSubscriptionEvent event) {
    var mirror = false;
    _widgets.add(event.remoteParticipant.widget(mirror));
  });
});

Using the DataTrack API

The DataTrack API lets you create a DataTrack channel which can be used to send low latency messages to zero or more receivers subscribed to the data.

Currently the only way you can start using a DataTrack is by specifying it in the ConnectOptions when connecting to a room

After you have connected to the Room, you have to wait until you receive the LocalDataTrackPublishedEvent before you can start sending data to the track. You can start listening for this event once you have connected to the room using the Room.onConnected listener:

// Connect to a room.
var room = await TwilioProgrammableVideo.connect(connectOptions);

room.onConnected((Room room) {
  // Once connected to the room start listening for the moment the LocalDataTrack gets published to the room.
  room.localParticipant.onDataTrackPublished.listen(_onLocalDataTrackPublished);
});

  // Once connected to the room start listening for the moment the LocalDataTrack gets published to the room.
  event.room.localParticipant.onDataTrackPublished.listen(_onLocalDataTrackPublished);
});

void _onLocalDataTrackPublished(LocalDataTrackPublishedEvent event) {
  // This event contains a localDataTrack you can use to send data.
  event.localDataTrackPublication.localDataTrack.send('Hello world');
}

If you want to receive data from a RemoteDataTrack you have to start listening to the track once the RemoteParticipant has started publishing it and you are subscribed to it:

// Connect to a room.
var room = await TwilioProgrammableVideo.connect(connectOptions);

room.onParticipantConnected((RoomParticipantConnectedEvent event) {
  // A participant connected, now you can start listening to RemoteParticipant events
  event.remoteParticipant.onDataTrackSubscribed.listen(_onDataTrackSubscribed)
});

void _onDataTrackSubscribed(RemoteDataTrackSubscriptionEvent event) {
  final dataTrack = event.remoteDataTrackPublication.remoteDataTrack;
  dataTrack.onMessage.listen(_onMessage);
}

void _onMessage(RemoteDataTrackStringMessageEvent event) {
  print('onMessage => ${event.remoteDataTrack.sid}, ${event.message}');
}

Remember, you will not receive messages that were send before you started listening.

Participating in a Room

Display a Camera Preview

Just like Twilio we totally get that you want to look fantastic before entering a Room. Sadly that isn't yet implemented so you should go analog and use a mirror.

Disconnect from a Room

You can disconnect from a Room you're currently participating in. Other Participants will receive a RoomParticipantDisconnectedEvent.

// To disconnect from a Room, we call:
await room.disconnect();

// This results in a call to Room#onDisconnected
room.onDisconnected((RoomDisconnectEvent event) {
  print('Disconnected from ${event.room.name}');
});

Room reconnection

A Room reconnection is triggered due to a signaling or media reconnection event.

/// Exception will be either TwilioException.signalingConnectionDisconnectedException or TwilioException.mediaConnectionErrorException
room.onReconnecting((RoomReconnectingEvent event) {
  print('Reconnecting to room ${event.room.name}, exception = ${event.exception.message}');
});

room.onReconnected((Room room) {
  print('Reconnected to room ${room.name}');
});

Configuring Audio, Video Input and Output devices

Taking advantage of the ability to control input and output devices lets you build a better end user experience.

Selecting a specific Video Input

The CameraCapturer class is used to provide video frames for LocalVideoTrack from a given CameraSource.

// Share your camera.
var cameraCapturer = CameraCapturer(CameraSource.FRONT_CAMERA);
var localVideoTrack = LocalVideoTrack(true, cameraCapturer);

// Render camera to a widget (only after connect event).
var mirror = true;
var widget = localVideoTrack.widget(mirror);
_widgets.add(widget);

// Switch the camera source.
var cameraSource = cameraCapturer.getCameraSource();
cameraCapturer.switchCamera();
primaryVideoView.setMirror(cameraSource == CameraSource.BACK_CAMERA);

Selecting a specific Audio output

Using the TwilioProgrammableVideo class, you can specify if audio is routed through the headset or speaker.

Note:

Calling this method before being connected to a room on iOS will result in nothing. If you wish to route audio through the headset or speaker call this method in the onConnected event.

// Route audio through speaker
TwilioProgrammableVideo.setSpeakerphoneOn(true);

// Route audio through headset
TwilioProgrammableVideo.setSpeakerphoneOn(false);

Playing audio files to provide a rich user experience

For the purposes of playing audio files while using this plugin, we recommend the ocarina plugin (v0.0.5 and upwards).

This recommendation comes after surveying the available plugins for this functionality in the Flutter ecosystem for plugins that play nice with this one.

The primary problem observed with other plugins that provide this functionality is that on iOS the majority of them modify the AVAudioSession mode, putting it into a playback only mode, and as a result preventing the video call from recording audio.

The secondary problem with audio file playback in iOS is that the operating system gives priority to the VoiceProcessingIO Audio Unit, causing other audio sources to be played at a greatly diminished volume when this AudioUnit is in use. To address this issue, we provide the custom AVAudioEngineDevice which users of the plugin may enable with the example that follows. AVAudioEngineDevice was designed with ocarina in mind, providing an interface for delegating audio file playback and management from that plugin to the AVAudioEngineDevice. It was adapted from Twilio's example.

To enable usage of the AVAudioEngineDevice, and delegate audio file playback management from ocarina to it, update your AppDelegate.swifts didFinishLaunch method as follows:

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)

    let audioDevice = AVAudioEngineDevice()
    SwiftTwilioProgrammableVideoPlugin.audioDevice = audioDevice
    SwiftOcarinaPlugin.useDelegate(
        load: audioDevice.addMusicNode,
        dispose: audioDevice.disposeMusicNode,
        play: audioDevice.playMusic,
        pause: audioDevice.pauseMusic,
        resume: audioDevice.resumeMusic,
        stop: audioDevice.stopMusic,
        volume: audioDevice.setMusicVolume,
        seek: audioDevice.seekPosition,
        position: audioDevice.getPosition
    )

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

Once you have done this, you should be able to continue using this plugin, and ocarina as normal.

Enable debug logging

Using the TwilioProgrammableVideo class, you can enable native and dart logging of the plugin.

var nativeEnabled = true;
var dartEnabled = true;
TwilioProgrammableVideo.debug(native: nativeEnabled, dart: dartEnabled);

Access Tokens

Keep in mind, you can't generate access tokens for programmable-video using the TestCredentials, make use of the LIVE credentials.

You can easily generate an access token in the Twilio dashboard with the Testing Tools to start testing your code. But we recommend you setup a backend to generate these tokens for you and secure your Twilio credentials. Like we do in our example app.

Events table

Reference table of all the events the plugin currently supports

Type	Event streams	Event data	Implemented
LocalParticipant	onAudioTrackPublished	LocalAudioTrackPublishedEvent	Android Only
LocalParticipant	onAudioTrackPublicationFailed	LocalAudioTrackPublicationFailedEvent	Android Only
LocalParticipant	onDataTrackPublished	LocalDataTrackPublishedEvent	Android Only
LocalParticipant	onDataTrackPublicationFailed	LocalDataTrackPublicationFailedEvent	Android Only
LocalParticipant	onVideoTrackPublished	LocalVideoTrackPublishedEvent	Android Only
LocalParticipant	onVideoTrackPublicationFailed	LocalVideoTrackPublicationFailedEvent	Android Only
RemoteDataTrack	onStringMessage	RemoteDataTrackStringMessageEvent	Android Only
RemoteDataTrack	onBufferMessage	RemoteDataTrackBufferMessageEvent	Android Only
RemoteParticipant	onAudioTrackDisabled	RemoteAudioTrackEvent	Yes
RemoteParticipant	onAudioTrackEnabled	RemoteAudioTrackEvent	Yes
RemoteParticipant	onAudioTrackPublished	RemoteAudioTrackEvent	Yes
RemoteParticipant	onAudioTrackSubscribed	RemoteAudioTrackSubscriptionEvent	Yes
RemoteParticipant	onAudioTrackSubscriptionFailed	RemoteAudioTrackSubscriptionFailedEvent	Yes
RemoteParticipant	onAudioTrackUnpublished	RemoteAudioTrackEvent	Yes
RemoteParticipant	onAudioTrackUnsubscribed	RemoteAudioTrackSubscriptionEvent	Yes
RemoteParticipant	onDataTrackPublished	RemoteDataTrackEvent	Yes
RemoteParticipant	onDataTrackSubscribed	RemoteDataTrackSubscriptionEvent	Yes
RemoteParticipant	onDataTrackSubscriptionFailed	RemoteDataTrackSubscriptionFailedEvent	Yes
RemoteParticipant	onDataTrackUnpublished	RemoteDataTrackEvent	Yes
RemoteParticipant	onDataTrackUnsubscribed	RemoteDataTrackSubscriptionEvent	Yes
RemoteParticipant	onVideoTrackDisabled	RemoteVideoTrackEvent	Yes
RemoteParticipant	onVideoTrackEnabled	RemoteVideoTrackEvent	Yes
RemoteParticipant	onVideoTrackPublished	RemoteVideoTrackEvent	Yes
RemoteParticipant	onVideoTrackSubscribed	RemoteVideoTrackSubscriptionEvent	Yes
RemoteParticipant	onVideoTrackSubscriptionFailed	RemoteVideoTrackSubscriptionFailedEvent	Yes
RemoteParticipant	onVideoTrackUnpublished	RemoteVideoTrackEvent	Yes
RemoteParticipant	onVideoTrackUnsubscribed	RemoteVideoTrackSubscriptionEvent	Yes
Room	onConnectFailure	RoomConnectFailureEvent	Yes
Room	onConnected	Room	Yes
Room	onDisconnected	RoomDisconnectedEvent	Yes
Room	onParticipantConnected	RoomParticipantConnectedEvent	Yes
Room	onParticipantDisconnected	RoomParticipantDisconnectedEvent	Yes
Room	onReconnected	Room	Yes
Room	onReconnecting	RoomReconnectingEvent	Yes
Room	onRecordingStarted	Room	Yes
Room	onRecordingStopped	Room	Yes

Development and Contributing

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