Implement system/desktop audio sharing on the Apple clients, feeding the
existing SCREEN_AUDIO Opus -> AEAD -> UDP path via vc_stream_feed_pcm. No
C++/protocol/codec changes -- the core was already ready (the Windows-only
loopback is #ifdef VOICECAT_HAS_LOOPBACK; off Windows the stream just waits
for fed PCM). Audio only; video is dropped.
macOS (in-process):
- ScreenAudioCapture.swift drives an audio-only SCStream
(excludesCurrentProcessAudio), converts Float32 -> int16 in the channel's
mono/stereo mode, and calls feedPcm. Capture starts on the self
.streamStarted event (effective config known then). Wired into
MainWindowController.screenAudioClicked().
iOS (forward-to-host, single session):
- VoiceCatBroadcast: a ReplayKit Broadcast Upload Extension consumes
.audioApp only, resamples to 48kHz int16 stereo (AVAudioConverter), and
writes a shared App Group SPSC ring (BroadcastAudioRing.swift). It does
not link libvoicecat.
- Host BroadcastAudioPump drains the ring (reacting to the extension's
Darwin notifications) and feeds the SCREEN_AUDIO stream it owns, downmixing
to mono when the channel is mono. Screen audio appears as a second stream
of the same user; no credentials persisted. UI is RPSystemBroadcastPicker
View in VoiceControlsView. Removes the speculative BroadcastCredentials.
Docs: voice.md s9, CLAUDE.md status, PROGRESS.md.
Diagnosed by comparing against TeamTalk5 (Client/iTeamTalk), which
achieves stereo mic + A2DP output. Five fixes:
1. configureStereoCapture now calls setPreferredInput +
setInputDataSource (mirroring TeamTalk5's SoundDevicesModel).
Previously omitted based on incorrect diagnosis that
setPreferredInput collapsed A2DP — the real culprit was
setPreferredInputNumberOfChannels(2), which neither project uses.
2. New C ABI: vc_audio_restart (full stop + re-init, unlike
suspend/resume which only stop/start). Swift wrapper added.
The withAudioSuspend wrapper that used it was removed after
on-device testing showed it killed all audio (including
VoiceOver) when switching presets — the core's
set_capture_channels handles engine restart internally.
3. Bluetooth options: Voice Chat preset now includes BOTH
.allowBluetoothHFP AND .allowBluetoothA2DP (matching TeamTalk5's
UtilSound.swift:228). Previously HFP-only blocked A2DP headphones.
4. Capture channels now reset when switching stereo→mono via
selectCaptureChannels/applyPreset. AudioSessionManager tracks
activeMicStreamId (set by SessionState on join/leave voice).
5. Docs synced: voice.md, tech-stack.md, architecture.md,
PROGRESS.md. Removed stale setPreferredInputNumberOfChannels(2)
references.
Verified: ctest --preset dev 21/21 green, iOS client builds.
Stereo mic + A2DP output still needs on-device debugging — the
core recipe is correct but iOS 26 route behavior requires
hands-on testing with a debugger.
Presets reorganized to give users choice at every level:
Always available (work with any output route):
- Voice Chat: AEC/AGC/HPF on, mono, system picks best route (BT HFP,
wired, or speaker). The standard iOS VoIP experience.
- Stereo Mic: Stereo built-in mic (front+back capsules), A2DP output
if BT connected else speaker/wired. Standard processing.
- Studio (No Processing): Stereo mic, no AEC/AGC/HPF (raw mode).
Maximum fidelity. Echo risk on speaker.
When Bluetooth connected:
- Bluetooth Headset (HFP): BT mic + BT output, AEC on, mono.
- BT Headphones + Mono Mic: A2DP output + built-in mic, mono, no AEC.
- BT Headphones + Stereo Mic: A2DP output + stereo built-in mic.
When wired headset/earpods connected:
- Wired Headset: Wired output + wired/built-in mic, AEC on, mono.
Always:
- Custom: shown when advanced settings don't match any preset.
Key changes from previous version:
- Stereo Mic is no longer gated behind Bluetooth — it's always available
and uses A2DP output if BT is connected, else speaker/wired.
- Wired headset detection (headphones/headsetMic/usbAudio port types)
with a dedicated preset.
- Voice Chat preset always available with AEC — the safe default.
- activePreset checks device-specific presets first so e.g. when BT is
connected and settings match 'Bluetooth Headset', it returns that
instead of the equivalent 'Voice Chat'.
- detectAudioDevices() replaces detectBluetooth(), detects both BT and
wired devices from currentRoute + availableInputs.
Replaces the flat list of audio settings with a preset picker that shows
context-appropriate options based on whether a Bluetooth device is connected.
Presets:
- Default (Phone Speaker): built-in mic + speaker, standard, mono
- Bluetooth Headset (HFP): BT mic + BT output, standard, mono — only shown
when a BT device is connected
- BT Headphones + Phone Mic: A2DP stereo output + built-in mic, standard,
mono — only shown when BT connected
- BT Headphones + Stereo Mic: A2DP stereo output + built-in mic stereo
(front+back capsules), standard, stereo — only shown when BT connected
- Custom: shown when advanced settings don't match any preset
When no Bluetooth device is connected, only 'Default' and 'Custom' appear,
with a hint to connect Bluetooth headphones for more options.
All granular controls (input port, orientation, polar pattern, mic mode,
channels, bluetooth mode, output route, AirPlay) are now under an
'Advanced Audio' disclosure group, collapsed by default.
IOSAudioRouter gains:
- AudioPreset enum with bluetoothMode/captureChannels/micMode/usesBuiltInMic
- hasBluetoothDevice detection (checks currentRoute + availableInputs for
bluetoothA2DP/bluetoothHFP port types)
- availablePresets (filtered by BT connection state)
- activePreset (computed from current settings)
- applyPreset() (sets all individual settings + finds built-in mic port UID)
Three bugs causing no audio output and no mic input:
1. .voiceChat mode + A2DP = output muted. The .voiceChat mode uses hardware
AEC/AGC/HPF but requires HFP-compatible routes. A2DP is NOT HFP — iOS
mutes the output because it can't set up the voice processing pipeline on
an A2DP route. Fix: use .default mode for Standard+A2DP (no hardware AEC,
but audio routes correctly). .voiceChat kept for HFP and speaker modes.
Added info warning in Settings UI for A2DP no-AEC.
2. Session lifecycle broken. stopMicStream() called deactivateAfterStreaming()
which deactivated the AVAudioSession — but the AudioEngine keeps running for
remote audio playback, so leaving voice killed all remote audio. And the
session was never activated when a remote user started talking (only on
Join Voice), so you couldn't hear anyone before joining voice. Fix:
- ensureSessionActive() replaces activateForStreaming() — idempotent, called
on Join Voice AND on .streamStarted (remote user starts talking).
- stopMicStream() no longer deactivates the session.
- deactivateSession() called only on disconnect from server.
- isSessionActive flag tracks state, updated by interruption handler.
3. setPreferredInputNumberOfChannels(1) called for mono — unnecessary (1 is
the default) and may put the session in a bad state on some devices. Fix:
only call it when stereo is explicitly selected. Also handle empty input
port ID (selecting 'Default' in the picker) correctly.
Added comprehensive route logging — after activation, logs the current output
and input route names so issues can be diagnosed from Console.app.
Three iOS client problems fixed plus a new core stereo-mic capture ABI:
1. Channel-id sync bug (mic button permanently dimmed): SessionState never
synced currentChannelId from the self user's channelId on connect, so the
mic button (gated on currentChannelId == 0) stayed dimmed. Added
syncSelfChannel() (mirrors macOS MainWindowController.swift:461,491,522);
called from init/.channelList/.userJoined/.userLeft/.userUpdated/.joinResult.
Added applyServerMuteState() + serverMuted/serverDeafened to VoiceState.
2. Join/Leave Voice button: replaced icon-only mic toggle with explicit
text button (parity with macOS). Mute/deafen disable when not in voice.
3. IOSAudioRouter.swift (new): full AVAudioSession routing layer — input
port selection, built-in mic orientation/polar patterns, Bluetooth
HFP/A2DP/Off modes, Standard/Raw mic processing, stereo capture, AirPlay,
UserDefaults persistence. AudioSessionManager delegates to it.
4. Core stereo-mic capture (append-only ABI): vc_set_capture_channels()
lets the core open the mic device in stereo (2-ch interleaved). LocalStream
gains capture_channels; ensure_audio_running reads it; audio_engine.cpp
capture_accum_ + on_capture updated to channel-aware accumulation. Test
test_stereo_mic_capture (headless, L!=R stereo round-trip). Swift wrapper
VoiceCatClient.setCaptureChannels.
5. Settings UI rework: AVAudioSession-derived input/output tree replaces
miniaudio device picker.
6. iOS deployment target raised to 18.0 (Package.swift + project.pbxproj).
swift-tools-version 6.0 with swiftLanguageModes .v5.
Docs: tech-stack.md, architecture.md, voice.md, roadmap.md, building.md
updated; stale 'vc_audio_suspend/resume deferred' claims corrected.
Verified: ctest --preset dev 21/21 green; swift test 6/6 green;
xcodebuild -target VoiceCatiOS -sdk iphonesimulator BUILD SUCCEEDED.
Full SwiftUI app at clients/apple/iOS/VoiceCatiOS.xcodeproj:
- 24 Swift source files: AppState + SessionState (@Observable @MainActor),
AudioSessionManager (AVAudioSession owner + interruption/route handling),
ServerListStore/SavedServer (App Group container + Keychain sharing),
and 14 SwiftUI views covering the full feature set
- NavigationSplitView on iPad, TabView on iPhone (horizontalSizeClass)
- Channel tree via OutlineGroup, user list with context menu admin actions
- PTT via DragGesture(minimumDistance: 0) + @GestureState
- onEvent closures hop to MainActor via Task { @MainActor in ... }
- App Group: group.cat.voice.VoiceCat (shared with future ReplayKit extension)
C ABI: add vc_audio_suspend / vc_audio_resume (AudioEngine::suspend/resume)
called by AudioSessionManager on AVAudioSession interruption events.
XCFramework: add ios-arm64 and ios-arm64-simulator slices to build-xcframework.sh;
Package.swift gains .iOS(.v17) platform; CMakePresets.json adds apple-ios /
apple-ios-sim presets with arm64-ios / arm64-ios-simulator vcpkg triplets.
Verified: xcodebuild -target VoiceCatiOS -sdk iphonesimulator26.5 BUILD SUCCEEDED.
