Ocarina is a simple and easy to use audio package for Flutter. Its goal is to support audio play from local file (from assets, or filesystem), And to support it across all platforms that Flutter runs.

Right now, we only support mobile (Android and iOS) and will eventually supporting Web and Desktop (Linux, MacOS and Windows).

If you have any questions, potential feature requests that you want to discuss with us you can join the Blue Fire Discord server.

Using a file on your assets

final player = OcarinaPlayer(
  asset: 'assets/Loop-Menu.wav',
  package: 'my_package_name',
  loop: true,
  volume: 0.8,
);

await player.load();

Using a file on the device filesystem

final player = OcarinaPlayer(
  filePath: '/SomeWhere/On/The/Device/Loop-Menu.wav',
  loop: true,
  volume: 0.8,
);

await player.load();

List of all available methods on the player instance

play

Starts playing

pause

Pauses playback

resume

Resume when playback if it was previously paused

stop

Stops the playback, it can be started again by calling play again.

seek(Duration)

Moves the playback postion to the passed Duration

position

Retrieves playback position in milliseconds.

updateVolume(double)

Updates the volume, must be a value between 0 and 1

dispose

Clears the loaded resources in memory, to use the instance again a subsequent call on the load method is required

This feature was developed in concert with the development of the AVAudioEngineDevice in twilio_programmable_video version 0.10.0 to address the issue in iOS in which the operating system gives priority to the VoiceProcessingIO Audio Unit, causing output volume of audio files from ocarina to be significantly diminished when used while a call is underway. While this was the reason for introducing this feature to ocarina, it was designed to be agnostic to the nature of the delegate. It is strongly advised that if you are writing your own delegate for iOS, that you seek to mirror the behaviour of ocarina itself as much as is possible so as to reduce the possibility of inconsistent behaviour across platforms.

If you found your way here because ocarina was recommended by twilio_programmable_video, the following modification to your AppDelegate will setup the AVAudioEngineDevice as the delegate for ocarina:

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

    let audioDevice = AVAudioEngineDevice.getInstance()
    SwiftTwilioProgrammableVideoPlugin.setCustomAudioDevice(
        audioDevice,
        onConnected: audioDevice.onConnected,
        onDisconnected: audioDevice.onDisconnected)
    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)
  }

This feature was also developed in concert with the ongoing development of the audio system for twilio_programmable_video, though it was designed to be agnostic to what other plugins you are using. As such, you can certainly add custom listeners via this mechanism to receive the same notifications. The only requirement is that they have the following signature:

Android:

(url: String, isPlaying: Boolean) -> Unit

iOS

(_ url: String, _ isPlaying: Bool) -> Void

If you wish to use this feature with twilio_programmable_video, simply add the following to your MainActivity.kt.

    private lateinit var PACKAGE_ID: String

    @RequiresApi(Build.VERSION_CODES.O)
    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        PACKAGE_ID = applicationContext.packageName
        OcarinaPlugin.addListener(PACKAGE_ID, TwilioProgrammableVideoPlugin.getAudioPlayerEventListener());
    }

    override fun cleanUpFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.cleanUpFlutterEngine(flutterEngine)
        OcarinaPlugin.removeListener(PACKAGE_ID)
    }

The benefit of using this feature (on Android) with the twilio_programmable_video is that it will enable that plugin to update the Audio Focus and usage of Bluetooth Sco based upon whether there are active audio players, in addition to an active call.

Alternatively, you can use it with your own listener for your own purposes.

This feature has not been integrated with twilio_programmable_video on iOS, out of preference for usage of the AVAudioEngineDevice as a delegate for ocarina.

If you wish to use this feature on iOS, add the following to your AppDelegate.swift:

    let bundleID = Bundle.main.bundleIdentifier

    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        SwiftOcarinaPlugin.addListener(bundleID!, ocarinaListener)
    }

    override func applicationWillTerminate(_ application: UIApplication) {
        SwiftOcarinaPlugin.removeListener(bundleID!)
    }

    func ocarinaListener(_ id: String, _ isPlaying: Bool) {
        // do things
    }