OBS Flutter Source

An OBS Studio source plugin that embeds the Flutter Engine on Windows, enabling rich, interactive UIs and logic built in Dart to be rendered directly in OBS.

Features

• Embed Flutter UI in OBS:
  Run your Flutter apps as a native OBS source, leveraging the full power of Flutter’s rendering, animations, and Dart logic inside streaming scenes.

• Full Video and Audio Support:

  • Renders Flutter output as video with dynamic resolution and pixel ratio.
  • Plays back audio from Flutter using a robust integration with miniaudio.
  • Supports loading, playing, stopping, and volume control for up to 256 simultaneous sounds.

• High-Performance Architecture:

  • Runs the Flutter Engine on a dedicated worker thread.
  • Uses a custom task runner so all Flutter platform messages and engine tasks execute on the same thread, preventing concurrency issues.
  • Efficient, lock-free command queues for both engine and audio commands.

• OBS Studio Integration:

  • Native video and audio source for OBS.
  • Exposes width, height, and pixel ratio properties for easy configuration.
  • Dynamically responds to OBS property changes (resolution, pixel ratio) and updates Flutter engine metrics live.

• Asset Management:

  • Automatically locates assets, ICU data, and AOT libraries adjacent to the plugin DLL.
  • Supports both absolute and relative asset paths for loading resources.

• Dart–OBS Communication:

  • Bi-directional messaging: Dart code can send commands (e.g., to play audio) via platform channels, and the C plugin acknowledges or responds.
  • Sample platform channel included for sending audio commands as JSON.

How It Works

• Worker Thread:
  The Flutter engine runs on a background thread dedicated to processing engine tasks and messages, keeping UI updates smooth and isolated from OBS’s main thread.

• Software Rendering:
  The plugin uses the Flutter Engine’s software renderer. It reads rendered pixel data into a texture and displays it in OBS as a standard source.

• Audio Integration:
  miniaudio is embedded for low-latency audio playback, managed entirely from Dart via platform messages.

• Lifecycle Management:
  Sources are reference-counted. The engine and worker thread exist only when at least one Flutter source is active.

Typical Use Cases

• Stream overlays with custom Dart/Flutter logic.
• Interactive widgets, animations, or games built with Flutter and controlled live from OBS.
• Audio-reactive visuals and overlays.

Example: Playing Audio from Dart

To play audio from Dart code running in your Flutter app, send a message like:

const message = {
  "cmd": "play",
  "id": 0,
  "asset": "sounds/notification.wav",
  "volume": 0.8,
  "loop": false
};
// Send via MethodChannel('obs_audio').invokeMethod('play', message)