Android client

Toolchain


Language	Kotlin 2.4.10
UI	Jetpack Compose, Material 3 Expressive (`material3` 1.4.0), Compose BOM 2025.09.00
Build	AGP 9.3.2, Gradle wrapper, `minSdk 24`, `target`/`compileSdk 35`
NDK	27.0.12077973, CMake 3.22.1 (RNNoise, `ANDROID_STL=none`)
ABIs	`arm64-v8a`, `armeabi-v7a`, `x86_64`
WebRTC	`io.github.webrtc-sdk:android:144.7559.14`
Networking	OkHttp 4.12 (WebSocket), Gson 2.11
Version	`1.8.9` / build `89` - `archivesName` = `Viora-v1.8.9-b89`

Why this WebRTC build

io.github.webrtc-sdk is LiveKit’s build of libwebrtc M144. It has the full H.265 RTP stack compiled in. The more common io.getstream:stream-webrtc-android lacks it - sending H.265 there SIGSEGVs in native code. The AAR also bundles the Chromium org.jni_zero runtime, which matters for R8.

Package layout


com.example.videocall
├── MainActivity.kt              # the only Activity - see below
├── data/
│   ├── AppSettings.kt            # SharedPreferences-backed reactive settings
│   ├── CallHistory.kt            # recent-calls list
│   └── AvatarArt.kt              # monogram / preset / photo avatar rendering
├── service/
│   └── CallForegroundService.kt  # camera|microphone|mediaProjection FGS + CallStyle notification
├── webrtc/
│   ├── WebRtcClient.kt           # the media engine (see "WebRTC pipeline")
│   ├── SignalingClient.kt        # OkHttp WebSocket wrapper
│   ├── SignalingModels.kt        # wire types
│   ├── CallStats.kt              # stats snapshot data class
│   ├── CallAudioRouter.kt        # earpiece / speaker / BT / wired routing
│   ├── CameraZoomController.kt   # pinch-zoom (Camera2 zoom ratio or crop)
│   ├── CameraCapabilities.kt     # which resolutions the cameras can actually capture
│   ├── DeviceLoadSampler.kt      # CPU %, battery temp, power draw
│   ├── RnnoiseProcessor.kt       # JNI bridge to libomnicall_audio.so
│   ├── MicGainProcessor.kt       # output gain on captured mic PCM
│   ├── ScreenAudioCapturer.kt    # device-playback capture during screen share
│   ├── CompositeAudioProcessing.kt  # chains the external audio processors
│   ├── AudioLevelMeter.kt        # RMS → smoothed 0..1 loudness envelope
│   ├── PeerConnectionObserver.kt / SimpleSdpObserver.kt  # no-op base impls
│   └── TextureViewRenderer.kt / VideoRenderer.kt   # Compose ↔ SurfaceViewRenderer / TextureView
└── ui/
    ├── screens/  HomeScreen, CallScreen, SettingsScreen, CallLogScreen
    ├── components/  CallControls, CallStatsPanel, ChatBottomSheet, MicModeSheet,
    │                AudioRouteSheet, ScreenShareResSheet, SpeakingWaveform,
    │                Avatar, AvatarPickerSheet, AvatarCropperDialog, FloatingNavBar
    ├── theme/  Color, Theme, Type  (+ the CallColorScheme call palette)
    └── navigation/  Screen

`MainActivity` - the orchestrator

There is one Activity. It is launchMode="singleTask" so re-launching from the launcher while the call is in Picture-in-Picture re-enters the existing instance instead of stacking a second copy.

Its responsibilities:

Area	What it owns
Navigation	A `Screen` enum (`HOME`, `CALL`, `CALL_LOG`, `SETTINGS`) driven by Compose state, plus a floating bottom nav bar
Permissions	Camera + mic request flow; builds `WebRtcClient` after grant so the Home preview lights up
Signaling dispatch	`dispatchSignalingMessage()` - the `when (msg.type)` that turns wire frames into `WebRtcClient` calls and state updates
Call state	`remotePeerId`, `isOfferer`, and the wall of `remote*` scalars (`remoteVideoEnabledState`, `remoteScreenSharingState`, `remoteContentRotation`, `connectionStateValue`, `peerLeftState`, …)
Lifecycle	`onStart`/`onStop` camera gate, `onUserLeaveHint` → PiP, `onPictureInPictureModeChanged`, `onResume` settings re-apply
PiP	`buildPipParams()`, the mic/camera/end `RemoteAction`s, the broadcast receiver that handles PiP button taps
Foreground service	Starts/refreshes `CallForegroundService` with a `CallStyle` notification summarising the call
ICE recovery	`iceRecoveryRunnable` - re-offers when the connection goes `DISCONNECTED`/`FAILED` and we’re the offerer

It’s a large file (~1,500 lines) because it is the join point between five independent subsystems. The multi-party roadmap factors the remote* scalars into a mutableStateListOf<Participant>.

`AppSettings`

A singleton object initialised in onCreate with AppSettings.init(context). Every field is a Compose mutableStateOf / mutableFloatStateOf backed by SharedPreferences (omnicall_settings.xml), so a settings change recomposes any screen reading it and survives a restart.

Setting	Type	Default
`displayName`	String	device model or `"You"`
`avatarType` / `avatarPreset` / `avatarPhoto`	enum / int / path	monogram
`themeMode`	`SYSTEM` / `LIGHT` / `DARK`	`SYSTEM`
`defaultCameraFront`	Boolean	`true`
`mirrorFrontCamera`	Boolean	`true`
`videoQuality`	`VideoQuality` (AUTO / Data Saver / HD / Full HD / 2K / 4K)	`AUTO`
`videoCodec`	`VideoCodec` (AV1 / H265 / H264)	`H264`
`micMode`	`MicMode` (Standard / Voice Isolation / Wide Spectrum)	`DEFAULT`
`micGain`	Float, 10 % steps	`1.0` (100 %)
`micOverboost`	Boolean (raises gain ceiling to 500 %)	`false`
`screenShareResolution` / `screenShareFps`	enum	HD / native
`screenShareAutoRotate`	Boolean	`false`
`serverUrl`	String (`wss://…`)	the hosted default

See the settings reference for the exact value maps.

Compose UI shape

HomeScreen - camera self-preview, recent room chips, a read-only “You’ll join as {name}” card (the name is not editable here - it’s set in Settings), a room-code field with a shuffle button, and the Join button.
CallScreen - the full call surface. A when on connection state renders waiting / connecting / connected / peer-left. The connected state is full-bleed remote video + a draggable SelfView + CallControls + an optional CallStatsPanel. A separate branch renders the PiP layout (remote video only).
SettingsScreen - cards for Profile, Appearance, Camera, Resolution, Codec, Screen share, Microphone, Studio Microphone, Server, About.
CallLogScreen - the CallHistory list.

The call UI has its own theme-aware palette: CallColorScheme with light/dark instances provided through a CompositionLocalProvider, exposed as a @Composable CallColors accessor so call sites don’t change.