mockingbird_web #

The web implementation of the mockingbird plugin. It is endorsed, so depending on mockingbird includes it automatically.

What it bundles #

• The Mockingbird engine compiled to WebAssembly with Emscripten: capture ingest, RNNoise, libfvad, the anomaly gate and the Opus encoder. The engine runs single-threaded inside the page; each pushed chunk is processed on the spot, so no cross-origin isolation headers are needed.
• Microphone capture through Web Audio: getUserMedia, an AudioContext opened at the engine's sample rate, and an AudioWorklet that delivers 20 ms int16 chunks, resampling if the browser would not open at that rate.
• Three assets, about 6 MB in total: mockingbird.js, mockingbird.wasm and the capture worklet. They load lazily from the app's asset bundle.

The Dart side reaches the engine through dart:js_interop; the mockingbird API is the same as on the other platforms.

What differs on the web #

Call await Mockingbird.initialize() before creating an engine. On the web it loads the module; on the other platforms it returns at once, so apps can call it unconditionally at startup.

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Mockingbird.initialize();
  runApp(const MyApp());
}

The browser asks for the microphone on the first start() of a capture engine. A refusal arrives as a MockingbirdBackendErrorEvent with status permission on engine.events.

Hosting the files elsewhere #

Set MockingbirdWeb.assetBaseUrl to a directory URL before Mockingbird.initialize() to serve the three files from a CDN instead of the asset bundle. The server must return application/wasm for mockingbird.wasm and a JavaScript type for the two scripts.

Requirements #

• A secure context (https:// or localhost) for getUserMedia.
• A browser with AudioWorklet and ES modules: every current Chrome, Edge, Firefox and Safari.