Two on-device bugs in the native iOS Voice-Processing path (Swift-only;
no core/ABI change).
1. Voice Chat (VPIO) silent playback: doStartMicStream() called
audioRestart() BEFORE startStream, so when the engine was already
running (a remote stream had started it) it reopened with
external_capture=false and opened a hardware miniaudio capture device.
The announce-result restart then early-returns (engine already running)
so that device was never dropped and fought the AVAudioEngine VPIO unit,
silencing playback. Now: setExternalPlayback first, then startStream
(stores external_feed synchronously), THEN audioRestart() — the core
reopens in full external mode (no hardware devices). Added VPIO
diagnostics: graph/route formats at start, ring written/read totals at
teardown.
2. Stereo Mic / Studio quiet earpiece: the .builtInMicBtA2dp presets omit
.defaultToSpeaker (it breaks A2DP) and skip forceSpeaker, so with no
Bluetooth connected output pinned to the quiet receiver. New
IOSAudioRouter.applyA2dpSpeakerFallback() overrides to the built-in
speaker when no external (A2DP/wired/AirPlay) output is present and
clears the override when one is — called after activation and on
device-change route changes.
iOS "voice chat" had echo and no noise suppression: real iOS AEC/NS/AGC
come only from Apple's Voice-Processing I/O unit (VPIO), but the core
plays/captures via miniaudio's plain RemoteIO units, so .voiceChat mode
alone never engaged AEC.
Core (ABI PATCH 1->2):
- vc_set_mixed_output_sink + vc_set_external_playback. In external mode the
AudioEngine opens no hardware playback device; a mixer-timer thread drives
on_playback (decode+mix) on a ~20ms cadence and ships the final mix to the
sink. start() also skips the hardware capture device when the MIC stream is
external_feed (AudioParams.external_capture).
- New white-box test test_external_playback (drives the timer with no hw).
iOS/Swift:
- StreamDescriptor.externalFeed; VoiceCatClient.setMixedOutputSink /
setExternalPlayback wrappers.
- IOSVoiceProcessingEngine: AVAudioEngine + setVoiceProcessingEnabled; mic
tap -> feedPcm, mixed-sink lock-free ring -> AVAudioSourceNode (both share
the VPIO unit so AEC has its reference signal).
- IOSAudioRouter.currentConfigUsesVoiceProcessing scopes VPIO to the AEC
presets; SessionState join/leave + reconcileVoicePath() switch paths;
Voice Chat defaults to speaker; Settings surfaces AEC/NS state.
Known: pending on-device verification; a few bugs to fix afterward.
Add a "speaker output" override so users can route audio to the built-in
speaker instead of the earpiece when no headphones/Bluetooth are connected.
Previously the receiver was the only fallback on the default Voice Chat preset.
The toggle inserts .defaultToSpeaker into the AVAudioSession category options
(skipped for the A2DP mode, where it would break Bluetooth routing). It yields
to connected BT/wired output and is orthogonal to preset matching. Exposed both
as a call-bar button in VoiceControlsView and a persisted Settings toggle.
After the stereo-mic/A2DP debugging settled, the iOS audio code carried
leftover TeamTalk5 comparison notes, source-line citations, TEMP DIAGNOSTIC
markers, and "this was the bug" narratives that no longer help. Reworded
those to state the current rules; kept the comments that document real
constraints (the setPreferredInputNumberOfChannels(2) trap, the re-entrancy
guard, the ma_context no-session-management config).
Comment-only — no behavior change. core builds, ctest --preset dev 21/21.
The real root cause of "selecting Stereo Mic kills headphone/A2DP output on Join
Voice." Every prior fix worked on the Swift IOSAudioRouter under the false premise
that "miniaudio does NOT touch AVAudioSession on iOS." It does: the core opened
devices via ma_device_init(nullptr, ...), and with a NULL context miniaudio 0.11.25
runs an iOS "hack" that sets the session category by device type, then
ma_context_init__coreaudio calls setCategory()+setActive() on every device open --
capture -> AVAudioSessionCategoryRecord with zero options. That wipes the
.playAndRecord category, the mode, and .allowBluetoothA2DP / .mixWithOthers /
.allowAirPlay that IOSAudioRouter had just configured, killing headphone/A2DP (and
even wired) output. Stereo presets break worst because they rely on the A2DP output
route the wipe removes. TeamTalk avoids this by opening RemoteIO/VPIO AudioUnits
directly and leaving the session entirely to the app.
Fix (core, cross-platform safe): AudioEngine now owns a ma_context built by
make_context_config() with coreaudio.sessionCategory = ma_ios_session_category_none
and noAudioSessionActivate/Deactivate = MA_TRUE, and routes all ma_device_init calls
(playback, capture, loopback) plus enumerate_devices through it. miniaudio no longer
touches AVAudioSession; IOSAudioRouter is the sole owner (the session is already
activated on connect in AppState before any device opens). Context is lazily inited
in start(), reused across restarts, uninited in ~AudioEngine.
Adds TEMP AudioSessionManager.logSessionState() diagnostics (after activate, on route
change, on .streamStarted) to verify on-device that the category stays
PlayAndRecord+allowBluetoothA2DP instead of flipping to Record. Remove once confirmed.
Windows: cmake --build --preset dev clean; ctest --preset dev 21/21.
iOS build + on-device verification pending on Mac.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Three coordinated fixes for the bug where enabling stereo mic capture
caused all audio output (A2DP, speaker, wired) to go silent:
1. audio_engine.cpp — open playback before capture
On iOS, starting the stereo capture AudioUnit can trigger an audio
route reconfiguration that drops A2DP before the playback device has
a chance to claim the route. Opening and starting the playback device
first commits the output route (A2DP), so iOS is less likely to drop
it when stereo capture activates afterward.
2. client.cpp — decouple set_capture_channels from engine restart
Previously vc_set_capture_channels() stopped and restarted the engine
immediately, which opened capture first (old ordering) and raced
against the settling AVAudioSession route. Now it only stores the
channel count; the caller (Swift via vc_audio_restart) controls when
the engine restarts, after the route has settled.
3. IOSAudioRouter.swift — call audioRestart() after channel config
selectCaptureChannels() and applyPreset() now call audioRestart()
after applyConfiguration() + setCaptureChannels(). This is the
vc_audio_restart() path that was added to the ABI in fdcc84f but
never wired up in the Swift layer. The restart sees the stored
channel count and reopens devices in the correct order (playback
first, capture second).
The doStartMicStream path is unaffected: setCaptureChannels is called
before the server acknowledges the stream (engine not yet running), so
ensure_audio_running() picks up capture_channels=2 directly when the
stream is confirmed and opens with the right count from the start.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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.
handleRouteChange called applyConfiguration() unconditionally, which called
setCategory/setPreferredInput/etc., which triggered another route-change
notification, which called applyConfiguration() again — an infinite loop that
burned CPU (phone slowdown) and repeatedly tore down/rebuilt the audio session
(audio cycling on/off, VoiceOver glitching).
Two fixes:
1. handleRouteChange now only re-applies config on external device changes
(.oldDeviceUnavailable / .newDeviceAvailable), not on .categoryChange /
.routeConfigurationChange which are triggered by our own setCategory calls.
2. IOSAudioRouter.applyConfiguration() gained a re-entrancy guard
(isApplyingConfiguration) for synchronous route-change notifications.
Also added os.Logger logging to both files (subsystem cat.voice.VoiceCatiOS)
so future issues can be debugged from Console.app on the Mac.
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.
