stera_recorder 0.0.1

ARKit and ARCore capture for Flutter, recorded straight to an MCAP dataset: RGB video, depth, point cloud, mesh and IMU, with session state and settings ready to bind to your own UI.

stera_recorder

The AR recording engine behind Stera: an ARKit (iOS) / ARCore (Android) capture session that writes an MCAP dataset — RGB video, depth, point cloud, mesh and IMU — plus the Dart API the app drives it with.

This is a Flutter plugin: the Swift and Kotlin implementations live here, and register themselves through GeneratedPluginRegistrant. There is no manual wiring in the host app's SceneDelegate / MainActivity.

Layout

lib/src/
  channels/    ar_recorder channel name + method enum (shipped native contract)
  service/     ArRecorderService — the method-channel / FFI facade
  ffi/         iOS interop: the ffigen output plus its typed wrapper
  data/        RecordingConfig and the recorder/tracking/resolution enums
  config/      RecorderPreferences + RecorderPermissions (host-supplied)
  managers/    ArRecordingConfigManager — the settings and their persistence
  providers/   ArRecorderProvider — the ChangeNotifier the UI binds to
  services/    audio cues, voice commands, battery monitoring
ios/           Swift Package (stera_recorder/Sources/) plus the podspec that
               compiles the same sources: session, frame pipeline, encoders,
               MCAP writers
android/       Kotlin: the same triad, plus the ARCore dependency
ffi/           ARRecorderInterop.h — ffigen input only, not compiled into the pod

Using it

The host app supplies persistence and permissions, then builds its own UI on top of ArRecorderProvider:

ChangeNotifierProvider(
  create: (_) => ArRecorderProvider(
    preferences: const KvStoreRecorderPreferences(),
    permissions: const AppRecorderPermissions(),
  ),
)

RecorderPrefKeys holds the persisted setting keys. They are shipped state — never change a value, or every user's recording settings reset.

Example

example/ is a one-screen app — permission, preview, record, stop — that runs the plugin without the rest of Stera:

cd example && flutter run

It needs a physical ARKit or ARCore device; there is no AR session on a simulator or emulator.

Native contract

The channel name (ar_recorder) and the method names in ArRecorderMethod must stay in lockstep with ArRecorderMethodChannelHandler.swift / .kt.

On iOS the hot paths (startRecording, stopRecording, getRecordingState, …) bypass the method channel and go through FFI. The generated bindings look classes up by their Objective-C runtime name, which is why ArRecorderInterop.swift pins them with explicit @objc(ARFRecordingConfig) style annotations — without those the names would carry the Swift module prefix and every FFI call would fail at class lookup.

Regenerate the bindings after changing ffi/ARRecorderInterop.h:

dart run tool/generate_ar_recorder_objc_bindings.dart

Known limitations

Two forward-compatibility items Flutter warns about today and will eventually enforce:

• Swift Package Manager. iOS ships as a CocoaPods pod only. SwiftPM can't express this target as-is — it mixes Swift with the Objective-C ObjCTryBlock shim, which SwiftPM requires to be a separate target.
• Built-in Kotlin. android/build.gradle still applies the Kotlin Gradle Plugin itself. Moving to AGP's built-in Kotlin needs AGP 9, above what the host app pins.