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fix(ios): stop miniaudio from clobbering AVAudioSession (stereo->A2DP output death)

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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>
This commit is contained in:
Talon
2026-06-20 02:34:07 +02:00
parent dcb7e6eeca
commit f1e1ef59ed
6 changed files with 142 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
core/src/audio/audio_engine.cpp
View File

@@ -138,7 +138,28 @@ void JitterBuffer::reset() {
AudioEngine::AudioEngine() = default;
AudioEngine::~AudioEngine() { stop(); }
AudioEngine::~AudioEngine() {
stop();
#ifdef VOICECAT_HAS_AUDIO
stop_loopback_capture(); // loopback has an independent lifecycle — close it before the context
if (context_inited_) {
ma_context_uninit(&context_);
context_inited_ = false;
}
#endif
}
#ifdef VOICECAT_HAS_AUDIO
ma_context_config AudioEngine::make_context_config() {
ma_context_config cfg = ma_context_config_init();
// iOS: leave AVAudioSession entirely to the Swift layer (IOSAudioRouter). See the
// make_context_config() declaration in audio_engine.h for the full rationale.
cfg.coreaudio.sessionCategory = ma_ios_session_category_none; // don't call setCategory
cfg.coreaudio.noAudioSessionActivate = MA_TRUE; // don't setActive(true) on device init
cfg.coreaudio.noAudioSessionDeactivate = MA_TRUE; // don't setActive(false) on device uninit
return cfg;
}
#endif
bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
if (running_.load()) return false;
@@ -163,6 +184,18 @@ bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
#endif
#ifdef VOICECAT_HAS_AUDIO
// Own the ma_context (lazily, reused across restarts) so miniaudio does not touch
// AVAudioSession on iOS — the Swift IOSAudioRouter is the sole session owner. Without
// this, ma_device_init(nullptr, ...) below would reset the session category to Record/
// Playback with no options on every open, killing headphone/A2DP output. See
// make_context_config() in audio_engine.h. If context init fails we fall back to a NULL
// context (degraded: miniaudio manages the session) rather than leaving audio dead.
if (!context_inited_) {
ma_context_config ctx_cfg = make_context_config();
context_inited_ = (ma_context_init(nullptr, 0, &ctx_cfg, &context_) == MA_SUCCESS);
}
ma_context* ctx = context_inited_ ? &context_ : nullptr;
// ── Playback device (opened first on iOS: commits the output route — e.g. A2DP —
// before the capture device starts. Starting stereo capture can trigger an iOS audio
// route reconfiguration; opening playback first ensures A2DP is already committed
@@ -179,7 +212,7 @@ bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
pb_cfg.pUserData = this;
pb_cfg.playback.pDeviceID = have_pb_id ? &pb_id : nullptr;
if (ma_device_init(nullptr, &pb_cfg, &playback_device_) == MA_SUCCESS) {
if (ma_device_init(ctx, &pb_cfg, &playback_device_) == MA_SUCCESS) {
if (ma_device_start(&playback_device_) == MA_SUCCESS) {
playback_started_ = true;
} else {
@@ -190,7 +223,7 @@ bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
// though WASAPI shared mode normally remixes transparently. Retry once at mono rather
// than leaving playback dead.
pb_cfg.playback.channels = 1;
if (ma_device_init(nullptr, &pb_cfg, &playback_device_) == MA_SUCCESS) {
if (ma_device_init(ctx, &pb_cfg, &playback_device_) == MA_SUCCESS) {
if (ma_device_start(&playback_device_) == MA_SUCCESS) {
playback_started_ = true;
params_.playback_channels = 1;
@@ -217,7 +250,7 @@ bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
// below becomes a zero-copy passthrough rather than a copy every two callbacks.
cap_cfg.periodSizeInFrames = static_cast<ma_uint32>(frame_samples_);
if (ma_device_init(nullptr, &cap_cfg, &capture_device_) == MA_SUCCESS) {
if (ma_device_init(ctx, &cap_cfg, &capture_device_) == MA_SUCCESS) {
if (ma_device_start(&capture_device_) == MA_SUCCESS) {
capture_started_ = true;
} else {
@@ -232,8 +265,12 @@ bool AudioEngine::start(const AudioParams& p, CaptureCallback capture_cb) {
std::vector<DeviceInfo> AudioEngine::enumerate_devices(bool capture) {
std::vector<DeviceInfo> result;
#ifdef VOICECAT_HAS_AUDIO
// Use the no-AVAudioSession-management config here too: device enumeration runs at
// SessionState init (refreshDevices) and on settings views, and a default-config context
// would call setCategory()/setActive() on iOS, disrupting the session the Swift layer owns.
ma_context ctx;
if (ma_context_init(nullptr, 0, nullptr, &ctx) != MA_SUCCESS) return result;
ma_context_config ctx_cfg = make_context_config();
if (ma_context_init(nullptr, 0, &ctx_cfg, &ctx) != MA_SUCCESS) return result;
ma_device_info* playback_infos = nullptr;
ma_uint32 playback_count = 0;
@@ -619,14 +656,19 @@ bool AudioEngine::start_loopback_capture(int kind, int channels) {
// along with everything else playing — an accepted self-echo-loop characteristic of
// desktop-audio capture, not a bug.
if (ma_device_init(nullptr, &cfg, &loopback_device_) != MA_SUCCESS) {
// Use the engine's owned context (shared with playback/capture) so loopback honors the
// same no-AVAudioSession-management config. Loopback is Windows/WASAPI-only today, where
// the coreaudio fields are irrelevant, but keep it consistent. start() inits the context
// before any loopback can be requested; fall back to NULL if it somehow isn't.
ma_context* ctx = context_inited_ ? &context_ : nullptr;
if (ma_device_init(ctx, &cfg, &loopback_device_) != MA_SUCCESS) {
// Fallback: some unusual render endpoints may reject channels=2 even though WASAPI
// shared mode normally remixes transparently. Retry once at mono (mirror the playback
// device's fallback in start()) rather than leaving screen-audio capture dead.
if (ch != 1) {
ch = 1;
cfg.capture.channels = 1;
if (ma_device_init(nullptr, &cfg, &loopback_device_) != MA_SUCCESS) return false;
if (ma_device_init(ctx, &cfg, &loopback_device_) != MA_SUCCESS) return false;
} else {
return false;
}

20
core/src/audio/audio_engine.h
View File

@@ -292,6 +292,26 @@ class AudioEngine {
void on_capture(const int16_t* pcm, ma_uint32 frames);
void on_playback(int16_t* out, ma_uint32 frames);
// Build the ma_context config that keeps miniaudio from managing AVAudioSession on iOS.
// With a NULL context, ma_device_init runs miniaudio's iOS "hack" (miniaudio.h ~44057)
// that calls setCategory()/setActive() on EVERY device open — capture →
// AVAudioSessionCategoryRecord with zero options. That obliterates the category/mode/
// options the Swift IOSAudioRouter configured (notably .playAndRecord and
// .allowBluetoothA2DP), which is what killed headphone/A2DP output when stereo was
// selected. The iOS Swift layer is the SOLE owner of the audio session (activated in
// AppState on connect, configured by IOSAudioRouter); miniaudio must only open the
// AudioUnit against the already-configured, already-active route. These coreaudio fields
// are no-ops on non-Apple backends. See PROGRESS.md / the "stereo mic kills output"
// investigation.
static ma_context_config make_context_config();
// Owned context, shared by the playback, capture, and loopback devices so they all honor
// the no-session-management config above. Lives for the engine's lifetime (init lazily in
// start(), reused across stop()/start() restarts, uninit in the destructor) — loopback has
// an independent start/stop lifecycle, so the context must outlive a single stop().
ma_context context_{};
bool context_inited_ = false;
ma_device capture_device_{};
ma_device playback_device_{};
bool capture_started_ = false;