AVAudioSession

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Use the AVAudioSession object to communicate to the system how you intend to use audio in your app.

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How to Monitor Any USB Audio or Video Device on macOS
USB cameras, microphones, HDMI capture cards, and audio interfaces are supposed to "just work" on macOS. In reality, it's often difficult to quickly access or monitor them without opening large and complicated software. Sometimes you simply want to see whether a USB camera is active. Sometimes you want to check an HDMI source connected through a capture card. And in other cases, you may want to use a Mac mini without a dedicated monitor by viewing its HDMI output through a USB capture device directly on another Mac. macOS supports many modern USB AV devices out of the box, but it surprisingly lacks a simple built-in utility for live monitoring and recording. Most users end up using oversized streaming or editing applications just to preview a video signal or monitor audio input. That becomes especially noticeable with: USB webcams HDMI capture adapters USB microphones audio interfaces secondary computers headless Mac mini setups A lightweight monitor utility is often much more practical when you only need real-time access to a device, want to record a stream, or quickly switch between multiple AV inputs. That's one of the reasons I built AV Monitor Pro  -  a native macOS app designed for monitoring and recording connected audio/video devices in real time. It can preview USB cameras, capture cards, microphones, and HDMI sources with minimal setup, and it's especially useful for workflows like running a Mac mini without a monitor, monitoring external devices, or recording live AV input directly on macOS.
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622
May ’26
CarPlay HID transport buttons remap to call-control during continuous mic capture (no opt-out API)
Hello, I am developing Uniq Intercom, a voice-only group communication app for motorcyclists (always-on intercom over WebRTC, used continuously for multi-hour rides). I am seeking guidance on an iOS audio session and CarPlay HID interaction I have not been able to resolve through documented APIs. Problem: As soon as my app activates the microphone (yellow recording indicator visible), iOS appears to classify the app as a real-time communication participant and CarPlay re-routes the steering-wheel / handlebar HID transport buttons (left / right / ok) from the media-control role to the call-control role (answer/decline). Because I do not register a CallKit / LiveCommunicationKit call (the session is a continuous group voice channel, not a discrete telephony call), there is no call object for those buttons to act upon — they effectively become inert. Why this matters: Motorcyclists rely on the intercom for 4–6 hour rides. CarPlay is now built into a growing number of modern motorcycles and with aftermarket display units virtually any bike, and any rider who uses any voice communication platform alongside it — Uniq Intercom, WhatsApp Call currently runs into this same handlebar button remap. With the buttons inert, the rider's only remaining option is to reach for the motorcycle's touchscreen to skip a track or change navigation — this is unsafe. The exact same remap behavior occurs during a real WhatsApp or Phone call — but for those the remap is correct (answer/decline maps to a real call). For continuous voice apps without a CallKit-style discrete call, no equivalent path exists today. As both an iOS developer and a motorcyclist, I would very much like to see this resolved — solving it would meaningfully improve safety for every rider using an iPhone with CarPlay. Configurations I have tested (all reproduce the symptom on iOS 18+ / 26 with wireless CarPlay): AVAudioSession.Category.playAndRecord + .voiceChat mode + various option combinations (duckOthers, mixWithOthers, allowBluetoothHFP, allowBluetoothA2DP, defaultToSpeaker) Same category with .videoChat mode (which @livekit/react-native defaults to) Same category with .default mode (re-applied after setAudioModeAsync to defeat any framework override) — confirmed Mode = Default for ~2 s window in audiomxd log before WebRTC's setActive cycle returned mode to .voiceChat. Buttons remained remapped during the .default window. Disabling MPRemoteCommandCenter and clearing MPNowPlayingInfoCenter.default().nowPlayingInfo JS-side override of WebRTC's global RTCAudioSessionConfiguration via @livekit/react-native's AudioSession.setAppleAudioConfiguration({audioMode: 'default'}) bridge, applied both before connect and after setAudioModeAsync to defeat library overrides In every case the audiomxd system log confirms our session goes active (Mode = VoiceChat or Default, Recording = YES), and CarPlay HID buttons are immediately remapped to call-control. The middle "OK" button remains functional because it is not part of the call-control mapping — confirming the buttons are not blocked, only re-purposed. The remap occurs the instant the iOS recording indicator appears, regardless of audio session mode. This led me to conclude the trigger is not audio session mode but the combination of microphone permission + active session + (likely) the AUVoiceIO unit instantiated by WebRTC. I cannot find a public API path to suppress this classification while maintaining the always-on continuous voice channel. My questions: Is there an entitlement or API that allows an app with active microphone capture to declare itself as a non-call media participant, keeping CarPlay HID transport buttons in the media role? Is AVAudioSession.setPrefersEchoCancelledInput(_:) (iOS 18+) the intended path for retaining platform AEC under .default mode without the focus-engine "communication priority" marking? Documentation is sparse on its CarPlay arbitration implications. Does the PushToTalk framework affect HID arbitration differently from playAndRecord + voiceChat? Our continuous-channel UX does not fit the PTT transmit-on-press model, but understanding the contrast would help. If no current API exists, is this something the iOS Audio team would consider for future SDKs? Solving this would meaningfully improve safety for motorcycle and adventure-sport users on iOS. Thank you for your time and any guidance you can offer. — Emre Erkaya / Uniq Intercom
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583
May ’26
CarPlay: AVSpeechUtterance not speaking/playing audio in some cars
I am having an issue with the code that I posted below. I capture voice in my CarPlay app, then allow the user to have it read back to them using AVSpeechUtterance. This works fine on some cars, but many of my beta testers report no audio being played. I have also experienced this in a rental car where the audio was either too quiet or the audio didn't play. Does anyone see any issue with the code that I posted? This is for CarPlay specifically. class CarPlayTextToSpeechService: NSObject, ObservableObject, AVSpeechSynthesizerDelegate { private var speechSynthesizer = AVSpeechSynthesizer() static let shared = CarPlayTextToSpeechService() /// Completion callback private var completionCallback: (() -> Void)? override init() { super.init() speechSynthesizer.delegate = self } func configureAudioSession() { do { try AVAudioSession.sharedInstance().setCategory(.playback, mode: .voicePrompt, options: [.duckOthers, .interruptSpokenAudioAndMixWithOthers, .allowBluetoothHFP]) } catch { print("Failed to set audio session category: \(error.localizedDescription)") } } public func speak(_ text: String, completion: (() -> Void)? = nil) { self.configureAudioSession() // Store the completion callback self.completionCallback = completion Task(priority: .high) { let speechUtterance = AVSpeechUtterance(string: text) let langCode = Locale.preferredLocalLanguageCountryCode if langCode == "en-US" { speechUtterance.voice = AVSpeechSynthesisVoice(identifier: AVSpeechSynthesisVoiceIdentifierAlex) } else { speechUtterance.voice = AVSpeechSynthesisVoice(language: langCode) } try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation) speechSynthesizer.speak(speechUtterance) } } func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) { Task { stopSpeech() try AVAudioSession.sharedInstance().setActive(false) } // Call completion callback if available self.completionCallback?() self.completionCallback = nil } func stopSpeech() { speechSynthesizer.stopSpeaking(at: .immediate) } }
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695
May ’26
AVAudioEngine startAndReturnError is now failing
I have a keyboard in my iOS Morse Code app that has always been able to play audio via AVAudioEngine. Recently it has been failing to produce audio. I see that startAndReturnError: is now failing with this error: Error Domain=com.apple.coreaudio.avfaudio Code=268435459 "(null)" UserInfo={failed call=err = PerformCommand(*outputNode, kAUInitialize, NULL, 0)} What's going on? Have keyboards lost the ability to play audio? Here's how I set things up: _engine = [AVAudioEngine new]; _prefs = [[NSUserDefaults alloc] initWithSuiteName:kSharedAppGroupID]; AVAudioMixerNode* mainMixerNode = _engine.mainMixerNode; AVAudioOutputNode* outputNode = _engine.outputNode; AVAudioFormat* format = [outputNode inputFormatForBus:0]; AVAudioFormat* inputFormat = [[AVAudioFormat alloc] initWithCommonFormat:AVAudioPCMFormatFloat32 sampleRate:44100 channels:1 interleaved:NO]; self.srcNode = [[AVAudioSourceNode alloc] initWithRenderBlock:^OSStatus(BOOL* _Nonnull isSilence, const AudioTimeStamp* _Nonnull timestamp, AVAudioFrameCount frameCount, AudioBufferList* _Nonnull outputData) { // This block builds the data, but is never called, so it is not the culprit. }]; [_engine attachNode:self.srcNode]; [_engine connect:self.srcNode to:mainMixerNode format:inputFormat]; [_engine connect:mainMixerNode to:_engine.outputNode format:nil]; [_engine prepare];
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398
Apr ’26
AlarmKit alerting-phase playback is significantly quieter than equivalent in-app playback using AVAudioSession(.playback)
Hi all, I’m trying to determine whether the loudness gap I’m seeing between AlarmKit alert playback and normal app-managed playback is expected behavior, a sound-asset issue, or something that should be reported as a bug. Observed behavior When an alarm fires through AlarmKit while the device is locked, the alarm sound is significantly quieter than playback of the same or very similar audio once the app is active and using its own audio session. The difference is large enough that it does not feel like a small mastering difference. It feels like the AlarmKit / system alerting path is using a meaningfully lower effective output level than normal app playback. Test scenario My repro is roughly: Schedule an alarm with AlarmKit. Lock the device. Let the alarm fire and listen during the system alerting phase. Enter the app / continue into the app-driven alarm experience. Play the same or equivalent alarm asset via app-managed playback. Result: AlarmKit / lock-screen alerting phase sounds much quieter. In-app playback sounds noticeably louder and fuller on the same device. Current implementation Alarm flow is currently split into two paths: 1) System alarm path Alarm scheduling and alert surfacing via AlarmKit Device may be locked No attempt to manipulate system volume No private APIs 2) In-app playback path After app activation, playback uses: AVAudioSession category .playback AVAudioPlayer Audio is routed as normal app playback This path sounds substantially louder than the AlarmKit path Important detail I am not asking how to override system volume. I understand that AlarmKit appears to follow the system ringer / alert volume model and does not expose a public API for custom alarm loudness. My question is narrower: Is it expected that the same asset or an equivalent asset will sound materially quieter during the AlarmKit alerting phase than during ordinary app playback with AVAudioSession(category: .playback)? Questions Is the lower perceived loudness during AlarmKit alerting an expected property of the framework / system alarm path? Does AlarmKit playback use a different output path, gain policy, processing chain, or speaker treatment than normal app playback with .playback? Are there recommended authoring constraints for AlarmKit alarm sounds to maximize perceived loudness on iPhone speakers? transient-heavy mix stronger mids reduced low-end different LUFS / peak strategy shorter attack, etc. Has anyone measured this directly with: the same WAV / CAF file same device same system volume locked AlarmKit playback vs unlocked in-app playback If this is not expected, would Apple want this reported as a bug with: sample project exact iOS version device model screen recording / audio recording What I’m trying to figure out For alarm-app UX, this matters a lot because: AlarmKit is the most reliable lock-screen/system path. But if AlarmKit playback is substantially quieter than normal app playback, the alarm experience is inconsistent depending on device/app state. That makes it hard to know whether to treat this as: expected system behavior, a framework limitation, an asset/mastering problem, or a bug. If anyone has tested this in a controlled way or received guidance from Apple/DTS, I’d appreciate any technical detail. Thanks.
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498
Apr ’26
Video Audio + Speech To Text
Hello, I am wondering if it is possible to have audio from my AirPods be sent to my speech to text service and at the same time have the built in mic audio input be sent to recording a video? I ask because I want my users to be able to say "CAPTURE" and I start recording a video (with audio from the built in mic) and then when the user says "STOP" I stop the recording.
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1.8k
Mar ’26
WatchOS: Can a background metronome app coexist with both Runna workout and Spotify playback?
I’m building a standalone Apple Watch metronome app for running. My goal is for these 3 apps to work at the same time: Runna owns the workout session Spotify plays music my app plays a metronome click in the background So far this is what I've found: Using HKWorkout​Session in my metronome app works well with Spotify, but conflicts with Runna and other workout apps, so I removed that. Using watchOS background audio with longFormAudio allows my app run in the background, and it can coexist with Runna. However, it seems to conflict with Spotify playback, and one app tends to stop the other. Is there any supported watchOS audio/background configuration that allows all 3 at once? More specifically this is what I need: another app owns HKWorkout​Session Spotify keeps playing my app keeps generating metronome clicks in the background Or is this simply not supported by current watchOS session/background rules? My metronome uses AVAudio​Engine / AVAudio​Player​Node with generated click audio. Thank you!
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1.5k
Mar ’26
AVAudioSession.outputVolume does not reflect system volume changes made while app is in background
I have a question regarding the behavior of AVAudioSession.sharedInstance().outputVolume. Observed behavior: When the app is in the foreground, I read audioSession.outputVolume (for example, 0.1). The app is then moved to the background. While the app is in the background, the user changes the system volume using the hardware buttons (for example, to 0.5). When the app returns to the foreground, audioSession.outputVolume still reports the previous value (0.1). From my testing, outputVolume only seems to update when the system volume is changed while the app is in the foreground. Volume changes made while the app is in the background are not reflected when the app returns to the foreground. Questions: According to Apple’s documentation for AVAudioSession.outputVolume: “The systemwide output volume set by the user.” https://developer.apple.com/documentation/avfaudio/avaudiosession/outputvolume However, based on our testing on iOS 18.6.2 and iOS 18.1, the observed behavior seems to differ from this description. Questions: The documentation states that outputVolume represents the system-wide volume set by the user. In our testing, the value does not reflect volume changes made while the app is in the background and only updates when the app is in the foreground.Is this the expected behavior of AVAudioSession.outputVolume? Is there any other recommended way in Swift to retrieve the current system volume that reflects user changes made both while the app is in the foreground and while it is in the background? Any clarification on the intended behavior or recommended handling would be greatly appreciated.
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414
Mar ’26
How should playback readiness be determined with AVSampleBufferAudioRenderer when using AirPlay?
I’m implementing a custom playback pipeline using AVSampleBufferAudioRenderer together with AVSampleBufferRenderSynchronizer. hasSufficientMediaDataForReliablePlaybackStart appears to be the intended signal for determining when enough media has been queued to start playback. For local playback, this works well in practice — the property becomes true after a reasonable amount of media is enqueued. However, when the output route is AirPlay, using this property becomes difficult: AirPlay requires significantly more buffered media before the renderer reports sufficient data. The required preroll amount is much larger than for local playback. For short assets, it is possible to enqueue the entire audio track and still never observe hasSufficientMediaDataForReliablePlaybackStart == true. In that situation there is no more media data to enqueue, but the renderer still reports that playback is not ready. Given this behavior, what is the recommended way to determine playback readiness when using AVSampleBufferAudioRenderer with AirPlay?
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453
Mar ’26
AudioQueueNewOutput blocks indefinitely on iOS 18.3 (hangs during creation)
Hi everyone, We’re encountering an issue where AudioQueueNewOutput blocks indefinitely and never returns, and we’re hoping to get some insight or confirmation if this is a known behavior/regression on newer iOS versions. Issue Description When triggering audio playback, we create an output AudioQueue using AudioQueueNewOutput. On some devices, the call hangs inside AudioQueueNewOutput and never returns, with no OSStatus error and no subsequent logs. This behavior is reproducible mainly on iOS 18.3. Earlier iOS versions do not show this issue under the same code path. if (audioDes) { mAudioDes.mSampleRate = audioDes->mSampleRate; mAudioDes.mBitsPerChannel = audioDes->mBitsPerChannel; mAudioDes.mChannelsPerFrame = audioDes->mChannelsPerFrame; mAudioDes.mFormatID = audioDes->mFormatID; mAudioDes.mFormatFlags = audioDes->mFormatFlags; mAudioDes.mFramesPerPacket = audioDes->mFramesPerPacket; mAudioDes.mBytesPerFrame = audioDes->mBytesPerFrame; mAudioDes.mBytesPerPacket = audioDes->mBytesPerFrame; mAudioDes.mReserved = 0; } // Create AudioQueue for output OSStatus status = AudioQueueNewOutput( &mAudioDes, AQOutputCallback, this, NULL, NULL, 0, &audioQueue ); code-block The thread blocks inside AudioQueueNewOutput, and execution never reaches the next line. Additional Notes / Observations ASBD is confirmed to be valid Standard PCM output Sample rate, channels, bytes per frame/packet all consistent Same ASBD works correctly on earlier iOS versions AudioQueue is created on a background thread Not on the main thread Not inside the AudioQueue callback On first creation, AVAudioSession may not yet be active setCategory and setActive:YES may be called shortly before creating the AudioQueue There may be a timing window where the session is still activating Issue is reported mainly on iOS 18.3 Multiple user reports point to iOS 18.3 devices Same code path works on iOS 17.x and earlier No OSStatus error is returned — the call simply never returns. Questions Is it expected that AudioQueueNewOutput can block indefinitely while waiting for AVAudioSession / audio route / HAL readiness? Have there been any behavior changes in iOS 18.3 regarding AudioQueue creation or AudioSession synchronization? Is it unsafe to call AudioQueueNewOutput before AVAudioSession is fully active on recent iOS versions? Are there recommended patterns (or delays / callbacks) to ensure AudioQueue creation does not hang? Any insight or confirmation would be greatly appreciated. Thanks in advance!
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216
Feb ’26
SiriKit: INPlayMediaIntent with a targeted speaker
I've got a streaming Radio app that loads an HLS stream into an AVAudioPlayer. I've set up an Intents extension that notifies SiriKit that my app must handle the INPlayMediaIntent in app, and, I'm able to successfully initiate the stream playing from my phone using the string "Play ". My intent handler in app looks like this: completionHandler(INPlayMediaIntentResponse(code: .success, userActivity: nil)) DispatchQueue.main.async { AudioPlayerService.shared.play() } The Audio Player service, in its init, does the following: try AVAudioSession.sharedInstance().setCategory( .playback, mode: .default, policy: .longFormAudio ) Additionally, in my Info.plist, I have the AirPlay optimization policy set to Long Form Audio. Having said all that, when I try to route my app to play "on a given HomePod speaker" ("play on ") the speaker routing instructions are never followed. I've looked and not been able to find where I might be able to instruct my app to follow the correct path here. I was assuming I could not trigger this behavior manually, as I believe I don't really have any control over AirPlay routing. Is there any guidance for working with SiriKit to do the right thing with regards to audio routing?
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924
Feb ’26
AVAudioSession.outputVolume not reporting correctly in iOS 18+ devices
I’m using the shared instance of AVAudioSession. After activating it with .setActive(true), I observe the outputVolume, and it correctly reports the device’s volume. However, after deactivating the session using .setActive(false), changing the volume, and then reactivating it again, the outputVolume returns the previous volume (before deactivation), not the current device volume. The correct volume is only reported after the user manually changes it again using physical buttons or Control Center, which triggers the observer. What I need is a way to retrieve the actual current device volume immediately after reactivating the audio session, even on the second and subsequent activations. Disabling and re-enabling the audio session is essential to how my application functions. I’ve tested this behavior with my colleagues, and the issue is consistently reproducible on iOS 18.0.1, iOS 18.1, iOS 18.3, iOS 18.5 and iOS 18.6.2. On devices running iOS 17.6.1 and iOS 16.0.3, outputVolume correctly reflects the current volume immediately after calling .setActive(true) multiple times.
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570
Feb ’26
Keeping PiP alive during third-party video recording (camera capture)
I’m building a teleprompter-style app that relies on Picture in Picture. PiP starts correctly on device. Everything works — until another app (e.g. TikTok / Instagram) starts active video recording. When camera capture begins in the foreground app, iOS terminates my PiP session. Some teleprompter apps appear to keep PiP active while recording in other apps, so I’m trying to understand the recommended architectural pattern for this scenario. Is there a documented approach or best practice to keep PiP stable during third-party camera capture? Looking specifically for guidance on the correct AVKit / AVAudioSession configuration for this use case.
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598
Feb ’26
failed to set category, reason: 未能完成操作。(OSStatus错误4097。)
When using the [AVAudioSession setCategory:withOptions:error:] API, the call hangs for a long time and eventually returns an error.This issue occurs on iOS 16, and did not appear in earlier versions. Thread 135: 0 libsystem_kernel.dylib 0x00000002478e3cd4 _mach_msg2_trap :8 (in libsystem_kernel.dylib) 1 libsystem_kernel.dylib 0x00000002478e7214 _mach_msg_overwrite :428 (in libsystem_kernel.dylib) 2 libsystem_kernel.dylib 0x00000002478e705c _mach_msg :24 (in libsystem_kernel.dylib) 3 libdispatch.dylib 0x00000001d63ffe84 __dispatch_mach_send_and_wait_for_reply :548 (in libdispatch.dylib) 4 libdispatch.dylib 0x00000001d6400224 _dispatch_mach_send_with_result_and_wait_for_reply :60 (in libdispatch.dylib) 5 libxpc.dylib 0x00000001b2114e04 _xpc_connection_send_message_with_reply_sync :256 (in libxpc.dylib) 6 Foundation 0x000000019b6249f0 ___NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__ :16 (in Foundation) 7 Foundation 0x000000019c06d1b4 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] :2100 (in Foundation) 8 CoreFoundation 0x000000019dfcb1cc ____forwarding___ :1072 (in CoreFoundation) 9 CoreFoundation 0x000000019dfd3200 ___forwarding_prep_0___ :96 (in CoreFoundation) 10 AudioSession 0x00000001c77498b0 __ZN4avas6client11SessionCore10HandlePingEv :192 (in AudioSession) 11 AudioSession 0x00000001c77497b0 ____ZN4avas6client11SessionCore12DispatchPingEv_block_invoke :52 (in AudioSession) 12 libdispatch.dylib 0x00000001d63e4adc __dispatch_call_block_and_release :32 (in libdispatch.dylib) 13 libdispatch.dylib 0x00000001d63fe7ec __dispatch_client_callout :16 (in libdispatch.dylib) 14 libdispatch.dylib 0x00000001d63ed468 __dispatch_lane_serial_drain :740 (in libdispatch.dylib) 15 libdispatch.dylib 0x00000001d63edf78 __dispatch_lane_invoke :440 (in libdispatch.dylib) 16 libdispatch.dylib 0x00000001d63f6f48 __dispatch_root_queue_drain :364 (in libdispatch.dylib) 17 libdispatch.dylib 0x00000001d63f6d08 __dispatch_worker_thread :268 (in libdispatch.dylib) 18 libsystem_pthread.dylib 0x00000001f9ff144c __pthread_start :136 (in libsystem_pthread.dylib) 19 libsystem_pthread.dylib 0x00000001f9fed8cc _thread_start :8 (in libsystem_pthread.dylib) Thread 132: 0 libsystem_kernel.dylib 0x00000002478e3cd4 _mach_msg2_trap :8 (in libsystem_kernel.dylib) 1 libsystem_kernel.dylib 0x00000002478e7214 _mach_msg_overwrite :428 (in libsystem_kernel.dylib) 2 libsystem_kernel.dylib 0x00000002478e705c _mach_msg :24 (in libsystem_kernel.dylib) 3 libdispatch.dylib 0x00000001d63ffe84 __dispatch_mach_send_and_wait_for_reply :548 (in libdispatch.dylib) 4 libdispatch.dylib 0x00000001d6400224 _dispatch_mach_send_with_result_and_wait_for_reply :60 (in libdispatch.dylib) 5 libxpc.dylib 0x00000001b2114e04 _xpc_connection_send_message_with_reply_sync :256 (in libxpc.dylib) 6 Foundation 0x000000019b6249f0 ___NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__ :16 (in Foundation) 7 Foundation 0x000000019c06d1b4 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] :2100 (in Foundation) 8 CoreFoundation 0x000000019dfcb1cc ____forwarding___ :1072 (in CoreFoundation) 9 CoreFoundation 0x000000019dfd3200 ___forwarding_prep_0___ :96 (in CoreFoundation) 10 AudioSession 0x00000001c7754198 __ZNK4avas6client11SessionCore18SetBatchPropertiesEP12NSDictionaryIP8NSStringPU25objcproto14NSSecureCoding11objc_objectEPU15__autoreleasingP7NSArrayIPS2_IS4_P8NSNumberEENS_30AVAudioSessionBatchSetStrategyEbb :548 (in AudioSession) 11 AudioSession 0x00000001c7753e58 __ZNK4avas6client11SessionCore20SetBatchPropertiesMXEP12NSDictionaryIP8NSStringPU25objcproto14NSSecureCoding11objc_objectE :92 (in AudioSession) 12 AudioSession 0x00000001c775179c __ZN4avas6client11SessionCore11setCategoryEP8NSStringS3_32AVAudioSessionRouteSharingPolicym :472 (in AudioSession) 13 AudioSession 0x00000001c7768f88 -[AVAudioSession setCategory:withOptions:error:] :68 (in AudioSession) 14 AlipayWallet 0x000000010140580c -[AVAudioSession(APMHook) apmhook_setCategory:withOptions:error:] APMHookAudioSession.m:35 (in AlipayWallet) 15 AlipayWallet 0x00000001014001a4 -[APMAudioSessionManager resume] APMAudioSessionManager.m:718 (in AlipayWallet) 16 libdispatch.dylib 0x00000001d63e4adc __dispatch_call_block_and_release :32 (in libdispatch.dylib) 17 libdispatch.dylib 0x00000001d63fe7ec __dispatch_client_callout :16 (in libdispatch.dylib) 18 libdispatch.dylib 0x00000001d63ed468 __dispatch_lane_serial_drain :740 (in libdispatch.dylib) 19 libdispatch.dylib 0x00000001d63edf44 __dispatch_lane_invoke :388 (in libdispatch.dylib) 20 libdispatch.dylib 0x00000001d63f83ec __dispatch_root_queue_drain_deferred_wlh :292 (in libdispatch.dylib) 21 libdispatch.dylib 0x00000001d63f7ce4 __dispatch_workloop_worker_thread :692 (in libdispatch.dylib) 22 libsystem_pthread.dylib 0x00000001f9fee3b8 __pthread_wqthread :292 (in libsystem_pthread.dylib) 23 libsystem_pthread.dylib 0x00000001f9fed8c0 _start_wqthread :8 (in libsystem_pthread.dylib)
2
0
942
Feb ’26
Is there any way to control alarm volume independently when using AlarmKit?
Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Hi there! I’m currently building an alarm app on iOS using AlarmKit, and I’m running into a fundamental limitation around volume control. When using AlarmKit, alarm sounds are played at the system ringer volume. My goal is simple in concept: Allow users to set an alarm volume inside the app, and have the alarm sound play at that volume when triggered. However, AlarmKit does not provide any API to control or override the alarm volume. I’ve explored several approaches(AVSystemController, MPVolumeView...), but none achieved the desired result. Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Any insights from developers who’ve shipped alarm apps, or from Apple engineers, would be greatly appreciated. Thanks in advance 🙏
1
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665
Jan ’26
Question about Apple Vision Pro audio input sampling rate for research
I am a graduate student conducting research in speech/audio signal processing and multimodal interaction. Apple Vision Pro is widely recognized as a multimodal interactive system supporting voice, eye, and gesture inputs. However, I could not find detailed specifications or documentation about the audio input sampling rate used by the device’s built-in microphone array when capturing user audio. Specifically, I would like to understand: What is the default audio input sampling rate (e.g., 16 kHz, 44.1 kHz, 48 kHz, etc.) for the Vision Pro’s microphones? When developing with visionOS / AVAudioSession / AVAudioEngine, is there a documented or recommended sampling rate for audio capture? Are there any best practices or settings for enabling high-quality voice capture on Vision Pro (especially for voice research tasks)? For context, my work involves voice processing, analysis, and possibly on-device real-time speech recognition. Any pointers to relevant APIs, documentation or examples (especially regarding audio capture buffer size or available formats on visionOS) would be very helpful. Thank you in advance! Best regards.
0
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251
Jan ’26
AVAudioSession setActive(true) fails after phone call when app is in background
I’m seeing what appears to be an iOS audio-session issue that occurs only when a phone call happens while the app is in the background. API: AVAudioSession, AVAudioRecorder Background Modes: Audio enabled (UIBackgroundModes = audio) Category: .playAndRecord Microphone permission: granted Expected Behavior If the app is recording audio in the background and a phone call interrupts it: AVAudioSession.interruptionNotification(.began) fires Call ends AVAudioSession.interruptionNotification(.ended) fires App should be able to re-activate its audio session and resume or restart recording Apple documentation suggests this should be supported for background audio apps. Actual Behavior When the app is in the background and phone call is ended: AVAudioSession.interruptionNotification(.ended) does fire Attempting to reactivate the audio session always fails: Error Domain=NSOSStatusErrorDomain Code=560557684 ("!int") "Session activation failed" The session appears to remain permanently “interrupted” Retrying activation (with delays) does not help Recreating AVAudioRecorder does not help Reactivation works only after the app is opened again
0
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226
Jan ’26
iOS React Native: Can two WebRTC stacks (Wazo & Jitsi) share media?
Hi everyone, I’m building a React Native iOS app where I’m integrating Wazo (native WebRTC) and Jitsi (WebView / WebRTC). Use case: Wazo is used to maintain a background call session (mainly signaling + audio keep-alive). Jitsi is used in the foreground for video calls. Problem: When Jitsi starts, it takes control of the microphone and camera. The Wazo call disconnects after ~5 minutes (likely due to media / audio session conflict). Even if Wazo audio/video is muted or tracks are disabled, the session still drops. My questions: Is it officially supported or recommended to run two WebRTC stacks (Wazo + Jitsi) simultaneously on iOS? Can Wazo stay connected without active audio/video tracks while Jitsi uses mic/camera? Is there a way to release Wazo media streams temporarily (but keep signaling alive) while Jitsi is loading or active? Are there any AVAudioSession / background mode limitations on iOS that make this impossible by design? If this is not supported, what is the recommended architecture (single WebRTC pipeline, switching media ownership, etc.)? Environment: iOS (React Native) Wazo SDK (native WebRTC) Jitsi Meet (WebView) CallKit + PushKit enabled Any guidance, documentation, or real-world experience would be greatly appreciated. Thanks in advance 🙏
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Jan ’26
iPhone 14 Pro: External USB mic not available in AVAudioSession for call apps, but works in Voice Memos & Instagram Live
I’m facing a strange audio routing issue that seems specific to iPhone 14 Pro / Pro Max. I’m using LiveKit (WebRTC) in a React Native app, which uses AVAudioSession internally for audio capture (VoIP / call-style usage). 🔍 What’s happening: I’m using an external USB microphone. On these devices: iPhone 11 → ✅ USB mic works iPhone 13 → ✅ USB mic works iPhone 17 Pro → ✅ USB mic works iPhone 14 Pro Max → ❌ USB mic does NOT work On iPhone 14 Pro Max: The same USB mic: ✅ Works in Voice Memos ✅ Works in Instagram Live ❌ Does NOT appear as an input option in my app ❌ Does NOT work in WhatsApp / Instagram calls Also: In my app on iPhone 14 Pro Max, iOS does not show the audio input selector UI On iPhone 17 Pro, the same app and same build does show the selector and the USB mic works ⚙️ My audio session config ( LiveKit ): await AudioSession.setAppleAudioConfiguration({ audioCategory: 'playAndRecord', audioMode: 'default', audioCategoryOptions: ['allowBluetooth', 'defaultToSpeaker'], }); await AudioSession.startAudioSession(); ❓ My questions: Is this a known limitation or behavior specific to iPhone 14 Pro / Pro Max? Does iPhone 14 Pro have different audio routing rules for call / VoIP mode compared to other devices? Why does the same USB mic work in recording apps (Voice Memos, Instagram Live) but not in call-style apps (LiveKit, WhatsApp, Instagram call)? Is there any documented difference in AVAudioSession behavior on iPhone 14 Pro regarding external USB audio inputs?
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Jan ’26
After unholding CallKit, the audio does not restore.
In my application, I use CallKit and have supportsHolding = true set. During my phone call, another call comes in (e.g., GSM). I accept the incoming call and put the current call on hold. If I end the active call myself, everything is fine, and CallKit calls the method provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession). However, if the other party ends the call, the second call remains on hold. In the application, the user clicks on unhold, and I notify CallKit that the hold has ended. But in this case, the didActivate method is not called at all. If I try to activate the audio myself after unhold, I receive the error: Domain=NSOSStatusErrorDomain Code=561017449 "Session activation failed" UserInfo={NSLocalizedDescription=Session activation failed} AVAudioSessionErrorInsufficientPriority == NSOSStatusErrorDomain Code: 561017449 What needs to be done for CallKit to activate my audio?
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Jan ’26
How to Monitor Any USB Audio or Video Device on macOS
USB cameras, microphones, HDMI capture cards, and audio interfaces are supposed to "just work" on macOS. In reality, it's often difficult to quickly access or monitor them without opening large and complicated software. Sometimes you simply want to see whether a USB camera is active. Sometimes you want to check an HDMI source connected through a capture card. And in other cases, you may want to use a Mac mini without a dedicated monitor by viewing its HDMI output through a USB capture device directly on another Mac. macOS supports many modern USB AV devices out of the box, but it surprisingly lacks a simple built-in utility for live monitoring and recording. Most users end up using oversized streaming or editing applications just to preview a video signal or monitor audio input. That becomes especially noticeable with: USB webcams HDMI capture adapters USB microphones audio interfaces secondary computers headless Mac mini setups A lightweight monitor utility is often much more practical when you only need real-time access to a device, want to record a stream, or quickly switch between multiple AV inputs. That's one of the reasons I built AV Monitor Pro  -  a native macOS app designed for monitoring and recording connected audio/video devices in real time. It can preview USB cameras, capture cards, microphones, and HDMI sources with minimal setup, and it's especially useful for workflows like running a Mac mini without a monitor, monitoring external devices, or recording live AV input directly on macOS.
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622
Activity
May ’26
CarPlay HID transport buttons remap to call-control during continuous mic capture (no opt-out API)
Hello, I am developing Uniq Intercom, a voice-only group communication app for motorcyclists (always-on intercom over WebRTC, used continuously for multi-hour rides). I am seeking guidance on an iOS audio session and CarPlay HID interaction I have not been able to resolve through documented APIs. Problem: As soon as my app activates the microphone (yellow recording indicator visible), iOS appears to classify the app as a real-time communication participant and CarPlay re-routes the steering-wheel / handlebar HID transport buttons (left / right / ok) from the media-control role to the call-control role (answer/decline). Because I do not register a CallKit / LiveCommunicationKit call (the session is a continuous group voice channel, not a discrete telephony call), there is no call object for those buttons to act upon — they effectively become inert. Why this matters: Motorcyclists rely on the intercom for 4–6 hour rides. CarPlay is now built into a growing number of modern motorcycles and with aftermarket display units virtually any bike, and any rider who uses any voice communication platform alongside it — Uniq Intercom, WhatsApp Call currently runs into this same handlebar button remap. With the buttons inert, the rider's only remaining option is to reach for the motorcycle's touchscreen to skip a track or change navigation — this is unsafe. The exact same remap behavior occurs during a real WhatsApp or Phone call — but for those the remap is correct (answer/decline maps to a real call). For continuous voice apps without a CallKit-style discrete call, no equivalent path exists today. As both an iOS developer and a motorcyclist, I would very much like to see this resolved — solving it would meaningfully improve safety for every rider using an iPhone with CarPlay. Configurations I have tested (all reproduce the symptom on iOS 18+ / 26 with wireless CarPlay): AVAudioSession.Category.playAndRecord + .voiceChat mode + various option combinations (duckOthers, mixWithOthers, allowBluetoothHFP, allowBluetoothA2DP, defaultToSpeaker) Same category with .videoChat mode (which @livekit/react-native defaults to) Same category with .default mode (re-applied after setAudioModeAsync to defeat any framework override) — confirmed Mode = Default for ~2 s window in audiomxd log before WebRTC's setActive cycle returned mode to .voiceChat. Buttons remained remapped during the .default window. Disabling MPRemoteCommandCenter and clearing MPNowPlayingInfoCenter.default().nowPlayingInfo JS-side override of WebRTC's global RTCAudioSessionConfiguration via @livekit/react-native's AudioSession.setAppleAudioConfiguration({audioMode: 'default'}) bridge, applied both before connect and after setAudioModeAsync to defeat library overrides In every case the audiomxd system log confirms our session goes active (Mode = VoiceChat or Default, Recording = YES), and CarPlay HID buttons are immediately remapped to call-control. The middle "OK" button remains functional because it is not part of the call-control mapping — confirming the buttons are not blocked, only re-purposed. The remap occurs the instant the iOS recording indicator appears, regardless of audio session mode. This led me to conclude the trigger is not audio session mode but the combination of microphone permission + active session + (likely) the AUVoiceIO unit instantiated by WebRTC. I cannot find a public API path to suppress this classification while maintaining the always-on continuous voice channel. My questions: Is there an entitlement or API that allows an app with active microphone capture to declare itself as a non-call media participant, keeping CarPlay HID transport buttons in the media role? Is AVAudioSession.setPrefersEchoCancelledInput(_:) (iOS 18+) the intended path for retaining platform AEC under .default mode without the focus-engine "communication priority" marking? Documentation is sparse on its CarPlay arbitration implications. Does the PushToTalk framework affect HID arbitration differently from playAndRecord + voiceChat? Our continuous-channel UX does not fit the PTT transmit-on-press model, but understanding the contrast would help. If no current API exists, is this something the iOS Audio team would consider for future SDKs? Solving this would meaningfully improve safety for motorcycle and adventure-sport users on iOS. Thank you for your time and any guidance you can offer. — Emre Erkaya / Uniq Intercom
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583
Activity
May ’26
CarPlay: AVSpeechUtterance not speaking/playing audio in some cars
I am having an issue with the code that I posted below. I capture voice in my CarPlay app, then allow the user to have it read back to them using AVSpeechUtterance. This works fine on some cars, but many of my beta testers report no audio being played. I have also experienced this in a rental car where the audio was either too quiet or the audio didn't play. Does anyone see any issue with the code that I posted? This is for CarPlay specifically. class CarPlayTextToSpeechService: NSObject, ObservableObject, AVSpeechSynthesizerDelegate { private var speechSynthesizer = AVSpeechSynthesizer() static let shared = CarPlayTextToSpeechService() /// Completion callback private var completionCallback: (() -> Void)? override init() { super.init() speechSynthesizer.delegate = self } func configureAudioSession() { do { try AVAudioSession.sharedInstance().setCategory(.playback, mode: .voicePrompt, options: [.duckOthers, .interruptSpokenAudioAndMixWithOthers, .allowBluetoothHFP]) } catch { print("Failed to set audio session category: \(error.localizedDescription)") } } public func speak(_ text: String, completion: (() -> Void)? = nil) { self.configureAudioSession() // Store the completion callback self.completionCallback = completion Task(priority: .high) { let speechUtterance = AVSpeechUtterance(string: text) let langCode = Locale.preferredLocalLanguageCountryCode if langCode == "en-US" { speechUtterance.voice = AVSpeechSynthesisVoice(identifier: AVSpeechSynthesisVoiceIdentifierAlex) } else { speechUtterance.voice = AVSpeechSynthesisVoice(language: langCode) } try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation) speechSynthesizer.speak(speechUtterance) } } func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) { Task { stopSpeech() try AVAudioSession.sharedInstance().setActive(false) } // Call completion callback if available self.completionCallback?() self.completionCallback = nil } func stopSpeech() { speechSynthesizer.stopSpeaking(at: .immediate) } }
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695
Activity
May ’26
AVAudioEngine startAndReturnError is now failing
I have a keyboard in my iOS Morse Code app that has always been able to play audio via AVAudioEngine. Recently it has been failing to produce audio. I see that startAndReturnError: is now failing with this error: Error Domain=com.apple.coreaudio.avfaudio Code=268435459 "(null)" UserInfo={failed call=err = PerformCommand(*outputNode, kAUInitialize, NULL, 0)} What's going on? Have keyboards lost the ability to play audio? Here's how I set things up: _engine = [AVAudioEngine new]; _prefs = [[NSUserDefaults alloc] initWithSuiteName:kSharedAppGroupID]; AVAudioMixerNode* mainMixerNode = _engine.mainMixerNode; AVAudioOutputNode* outputNode = _engine.outputNode; AVAudioFormat* format = [outputNode inputFormatForBus:0]; AVAudioFormat* inputFormat = [[AVAudioFormat alloc] initWithCommonFormat:AVAudioPCMFormatFloat32 sampleRate:44100 channels:1 interleaved:NO]; self.srcNode = [[AVAudioSourceNode alloc] initWithRenderBlock:^OSStatus(BOOL* _Nonnull isSilence, const AudioTimeStamp* _Nonnull timestamp, AVAudioFrameCount frameCount, AudioBufferList* _Nonnull outputData) { // This block builds the data, but is never called, so it is not the culprit. }]; [_engine attachNode:self.srcNode]; [_engine connect:self.srcNode to:mainMixerNode format:inputFormat]; [_engine connect:mainMixerNode to:_engine.outputNode format:nil]; [_engine prepare];
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398
Activity
Apr ’26
AlarmKit alerting-phase playback is significantly quieter than equivalent in-app playback using AVAudioSession(.playback)
Hi all, I’m trying to determine whether the loudness gap I’m seeing between AlarmKit alert playback and normal app-managed playback is expected behavior, a sound-asset issue, or something that should be reported as a bug. Observed behavior When an alarm fires through AlarmKit while the device is locked, the alarm sound is significantly quieter than playback of the same or very similar audio once the app is active and using its own audio session. The difference is large enough that it does not feel like a small mastering difference. It feels like the AlarmKit / system alerting path is using a meaningfully lower effective output level than normal app playback. Test scenario My repro is roughly: Schedule an alarm with AlarmKit. Lock the device. Let the alarm fire and listen during the system alerting phase. Enter the app / continue into the app-driven alarm experience. Play the same or equivalent alarm asset via app-managed playback. Result: AlarmKit / lock-screen alerting phase sounds much quieter. In-app playback sounds noticeably louder and fuller on the same device. Current implementation Alarm flow is currently split into two paths: 1) System alarm path Alarm scheduling and alert surfacing via AlarmKit Device may be locked No attempt to manipulate system volume No private APIs 2) In-app playback path After app activation, playback uses: AVAudioSession category .playback AVAudioPlayer Audio is routed as normal app playback This path sounds substantially louder than the AlarmKit path Important detail I am not asking how to override system volume. I understand that AlarmKit appears to follow the system ringer / alert volume model and does not expose a public API for custom alarm loudness. My question is narrower: Is it expected that the same asset or an equivalent asset will sound materially quieter during the AlarmKit alerting phase than during ordinary app playback with AVAudioSession(category: .playback)? Questions Is the lower perceived loudness during AlarmKit alerting an expected property of the framework / system alarm path? Does AlarmKit playback use a different output path, gain policy, processing chain, or speaker treatment than normal app playback with .playback? Are there recommended authoring constraints for AlarmKit alarm sounds to maximize perceived loudness on iPhone speakers? transient-heavy mix stronger mids reduced low-end different LUFS / peak strategy shorter attack, etc. Has anyone measured this directly with: the same WAV / CAF file same device same system volume locked AlarmKit playback vs unlocked in-app playback If this is not expected, would Apple want this reported as a bug with: sample project exact iOS version device model screen recording / audio recording What I’m trying to figure out For alarm-app UX, this matters a lot because: AlarmKit is the most reliable lock-screen/system path. But if AlarmKit playback is substantially quieter than normal app playback, the alarm experience is inconsistent depending on device/app state. That makes it hard to know whether to treat this as: expected system behavior, a framework limitation, an asset/mastering problem, or a bug. If anyone has tested this in a controlled way or received guidance from Apple/DTS, I’d appreciate any technical detail. Thanks.
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2
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498
Activity
Apr ’26
Video Audio + Speech To Text
Hello, I am wondering if it is possible to have audio from my AirPods be sent to my speech to text service and at the same time have the built in mic audio input be sent to recording a video? I ask because I want my users to be able to say "CAPTURE" and I start recording a video (with audio from the built in mic) and then when the user says "STOP" I stop the recording.
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1.8k
Activity
Mar ’26
WatchOS: Can a background metronome app coexist with both Runna workout and Spotify playback?
I’m building a standalone Apple Watch metronome app for running. My goal is for these 3 apps to work at the same time: Runna owns the workout session Spotify plays music my app plays a metronome click in the background So far this is what I've found: Using HKWorkout​Session in my metronome app works well with Spotify, but conflicts with Runna and other workout apps, so I removed that. Using watchOS background audio with longFormAudio allows my app run in the background, and it can coexist with Runna. However, it seems to conflict with Spotify playback, and one app tends to stop the other. Is there any supported watchOS audio/background configuration that allows all 3 at once? More specifically this is what I need: another app owns HKWorkout​Session Spotify keeps playing my app keeps generating metronome clicks in the background Or is this simply not supported by current watchOS session/background rules? My metronome uses AVAudio​Engine / AVAudio​Player​Node with generated click audio. Thank you!
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4
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1.5k
Activity
Mar ’26
AVAudioSession.outputVolume does not reflect system volume changes made while app is in background
I have a question regarding the behavior of AVAudioSession.sharedInstance().outputVolume. Observed behavior: When the app is in the foreground, I read audioSession.outputVolume (for example, 0.1). The app is then moved to the background. While the app is in the background, the user changes the system volume using the hardware buttons (for example, to 0.5). When the app returns to the foreground, audioSession.outputVolume still reports the previous value (0.1). From my testing, outputVolume only seems to update when the system volume is changed while the app is in the foreground. Volume changes made while the app is in the background are not reflected when the app returns to the foreground. Questions: According to Apple’s documentation for AVAudioSession.outputVolume: “The systemwide output volume set by the user.” https://developer.apple.com/documentation/avfaudio/avaudiosession/outputvolume However, based on our testing on iOS 18.6.2 and iOS 18.1, the observed behavior seems to differ from this description. Questions: The documentation states that outputVolume represents the system-wide volume set by the user. In our testing, the value does not reflect volume changes made while the app is in the background and only updates when the app is in the foreground.Is this the expected behavior of AVAudioSession.outputVolume? Is there any other recommended way in Swift to retrieve the current system volume that reflects user changes made both while the app is in the foreground and while it is in the background? Any clarification on the intended behavior or recommended handling would be greatly appreciated.
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2
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414
Activity
Mar ’26
How should playback readiness be determined with AVSampleBufferAudioRenderer when using AirPlay?
I’m implementing a custom playback pipeline using AVSampleBufferAudioRenderer together with AVSampleBufferRenderSynchronizer. hasSufficientMediaDataForReliablePlaybackStart appears to be the intended signal for determining when enough media has been queued to start playback. For local playback, this works well in practice — the property becomes true after a reasonable amount of media is enqueued. However, when the output route is AirPlay, using this property becomes difficult: AirPlay requires significantly more buffered media before the renderer reports sufficient data. The required preroll amount is much larger than for local playback. For short assets, it is possible to enqueue the entire audio track and still never observe hasSufficientMediaDataForReliablePlaybackStart == true. In that situation there is no more media data to enqueue, but the renderer still reports that playback is not ready. Given this behavior, what is the recommended way to determine playback readiness when using AVSampleBufferAudioRenderer with AirPlay?
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453
Activity
Mar ’26
AudioQueueNewOutput blocks indefinitely on iOS 18.3 (hangs during creation)
Hi everyone, We’re encountering an issue where AudioQueueNewOutput blocks indefinitely and never returns, and we’re hoping to get some insight or confirmation if this is a known behavior/regression on newer iOS versions. Issue Description When triggering audio playback, we create an output AudioQueue using AudioQueueNewOutput. On some devices, the call hangs inside AudioQueueNewOutput and never returns, with no OSStatus error and no subsequent logs. This behavior is reproducible mainly on iOS 18.3. Earlier iOS versions do not show this issue under the same code path. if (audioDes) { mAudioDes.mSampleRate = audioDes->mSampleRate; mAudioDes.mBitsPerChannel = audioDes->mBitsPerChannel; mAudioDes.mChannelsPerFrame = audioDes->mChannelsPerFrame; mAudioDes.mFormatID = audioDes->mFormatID; mAudioDes.mFormatFlags = audioDes->mFormatFlags; mAudioDes.mFramesPerPacket = audioDes->mFramesPerPacket; mAudioDes.mBytesPerFrame = audioDes->mBytesPerFrame; mAudioDes.mBytesPerPacket = audioDes->mBytesPerFrame; mAudioDes.mReserved = 0; } // Create AudioQueue for output OSStatus status = AudioQueueNewOutput( &mAudioDes, AQOutputCallback, this, NULL, NULL, 0, &audioQueue ); code-block The thread blocks inside AudioQueueNewOutput, and execution never reaches the next line. Additional Notes / Observations ASBD is confirmed to be valid Standard PCM output Sample rate, channels, bytes per frame/packet all consistent Same ASBD works correctly on earlier iOS versions AudioQueue is created on a background thread Not on the main thread Not inside the AudioQueue callback On first creation, AVAudioSession may not yet be active setCategory and setActive:YES may be called shortly before creating the AudioQueue There may be a timing window where the session is still activating Issue is reported mainly on iOS 18.3 Multiple user reports point to iOS 18.3 devices Same code path works on iOS 17.x and earlier No OSStatus error is returned — the call simply never returns. Questions Is it expected that AudioQueueNewOutput can block indefinitely while waiting for AVAudioSession / audio route / HAL readiness? Have there been any behavior changes in iOS 18.3 regarding AudioQueue creation or AudioSession synchronization? Is it unsafe to call AudioQueueNewOutput before AVAudioSession is fully active on recent iOS versions? Are there recommended patterns (or delays / callbacks) to ensure AudioQueue creation does not hang? Any insight or confirmation would be greatly appreciated. Thanks in advance!
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216
Activity
Feb ’26
SiriKit: INPlayMediaIntent with a targeted speaker
I've got a streaming Radio app that loads an HLS stream into an AVAudioPlayer. I've set up an Intents extension that notifies SiriKit that my app must handle the INPlayMediaIntent in app, and, I'm able to successfully initiate the stream playing from my phone using the string "Play ". My intent handler in app looks like this: completionHandler(INPlayMediaIntentResponse(code: .success, userActivity: nil)) DispatchQueue.main.async { AudioPlayerService.shared.play() } The Audio Player service, in its init, does the following: try AVAudioSession.sharedInstance().setCategory( .playback, mode: .default, policy: .longFormAudio ) Additionally, in my Info.plist, I have the AirPlay optimization policy set to Long Form Audio. Having said all that, when I try to route my app to play "on a given HomePod speaker" ("play on ") the speaker routing instructions are never followed. I've looked and not been able to find where I might be able to instruct my app to follow the correct path here. I was assuming I could not trigger this behavior manually, as I believe I don't really have any control over AirPlay routing. Is there any guidance for working with SiriKit to do the right thing with regards to audio routing?
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924
Activity
Feb ’26
AVAudioSession.outputVolume not reporting correctly in iOS 18+ devices
I’m using the shared instance of AVAudioSession. After activating it with .setActive(true), I observe the outputVolume, and it correctly reports the device’s volume. However, after deactivating the session using .setActive(false), changing the volume, and then reactivating it again, the outputVolume returns the previous volume (before deactivation), not the current device volume. The correct volume is only reported after the user manually changes it again using physical buttons or Control Center, which triggers the observer. What I need is a way to retrieve the actual current device volume immediately after reactivating the audio session, even on the second and subsequent activations. Disabling and re-enabling the audio session is essential to how my application functions. I’ve tested this behavior with my colleagues, and the issue is consistently reproducible on iOS 18.0.1, iOS 18.1, iOS 18.3, iOS 18.5 and iOS 18.6.2. On devices running iOS 17.6.1 and iOS 16.0.3, outputVolume correctly reflects the current volume immediately after calling .setActive(true) multiple times.
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3
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570
Activity
Feb ’26
Keeping PiP alive during third-party video recording (camera capture)
I’m building a teleprompter-style app that relies on Picture in Picture. PiP starts correctly on device. Everything works — until another app (e.g. TikTok / Instagram) starts active video recording. When camera capture begins in the foreground app, iOS terminates my PiP session. Some teleprompter apps appear to keep PiP active while recording in other apps, so I’m trying to understand the recommended architectural pattern for this scenario. Is there a documented approach or best practice to keep PiP stable during third-party camera capture? Looking specifically for guidance on the correct AVKit / AVAudioSession configuration for this use case.
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598
Activity
Feb ’26
failed to set category, reason: 未能完成操作。(OSStatus错误4097。)
When using the [AVAudioSession setCategory:withOptions:error:] API, the call hangs for a long time and eventually returns an error.This issue occurs on iOS 16, and did not appear in earlier versions. Thread 135: 0 libsystem_kernel.dylib 0x00000002478e3cd4 _mach_msg2_trap :8 (in libsystem_kernel.dylib) 1 libsystem_kernel.dylib 0x00000002478e7214 _mach_msg_overwrite :428 (in libsystem_kernel.dylib) 2 libsystem_kernel.dylib 0x00000002478e705c _mach_msg :24 (in libsystem_kernel.dylib) 3 libdispatch.dylib 0x00000001d63ffe84 __dispatch_mach_send_and_wait_for_reply :548 (in libdispatch.dylib) 4 libdispatch.dylib 0x00000001d6400224 _dispatch_mach_send_with_result_and_wait_for_reply :60 (in libdispatch.dylib) 5 libxpc.dylib 0x00000001b2114e04 _xpc_connection_send_message_with_reply_sync :256 (in libxpc.dylib) 6 Foundation 0x000000019b6249f0 ___NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__ :16 (in Foundation) 7 Foundation 0x000000019c06d1b4 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] :2100 (in Foundation) 8 CoreFoundation 0x000000019dfcb1cc ____forwarding___ :1072 (in CoreFoundation) 9 CoreFoundation 0x000000019dfd3200 ___forwarding_prep_0___ :96 (in CoreFoundation) 10 AudioSession 0x00000001c77498b0 __ZN4avas6client11SessionCore10HandlePingEv :192 (in AudioSession) 11 AudioSession 0x00000001c77497b0 ____ZN4avas6client11SessionCore12DispatchPingEv_block_invoke :52 (in AudioSession) 12 libdispatch.dylib 0x00000001d63e4adc __dispatch_call_block_and_release :32 (in libdispatch.dylib) 13 libdispatch.dylib 0x00000001d63fe7ec __dispatch_client_callout :16 (in libdispatch.dylib) 14 libdispatch.dylib 0x00000001d63ed468 __dispatch_lane_serial_drain :740 (in libdispatch.dylib) 15 libdispatch.dylib 0x00000001d63edf78 __dispatch_lane_invoke :440 (in libdispatch.dylib) 16 libdispatch.dylib 0x00000001d63f6f48 __dispatch_root_queue_drain :364 (in libdispatch.dylib) 17 libdispatch.dylib 0x00000001d63f6d08 __dispatch_worker_thread :268 (in libdispatch.dylib) 18 libsystem_pthread.dylib 0x00000001f9ff144c __pthread_start :136 (in libsystem_pthread.dylib) 19 libsystem_pthread.dylib 0x00000001f9fed8cc _thread_start :8 (in libsystem_pthread.dylib) Thread 132: 0 libsystem_kernel.dylib 0x00000002478e3cd4 _mach_msg2_trap :8 (in libsystem_kernel.dylib) 1 libsystem_kernel.dylib 0x00000002478e7214 _mach_msg_overwrite :428 (in libsystem_kernel.dylib) 2 libsystem_kernel.dylib 0x00000002478e705c _mach_msg :24 (in libsystem_kernel.dylib) 3 libdispatch.dylib 0x00000001d63ffe84 __dispatch_mach_send_and_wait_for_reply :548 (in libdispatch.dylib) 4 libdispatch.dylib 0x00000001d6400224 _dispatch_mach_send_with_result_and_wait_for_reply :60 (in libdispatch.dylib) 5 libxpc.dylib 0x00000001b2114e04 _xpc_connection_send_message_with_reply_sync :256 (in libxpc.dylib) 6 Foundation 0x000000019b6249f0 ___NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__ :16 (in Foundation) 7 Foundation 0x000000019c06d1b4 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] :2100 (in Foundation) 8 CoreFoundation 0x000000019dfcb1cc ____forwarding___ :1072 (in CoreFoundation) 9 CoreFoundation 0x000000019dfd3200 ___forwarding_prep_0___ :96 (in CoreFoundation) 10 AudioSession 0x00000001c7754198 __ZNK4avas6client11SessionCore18SetBatchPropertiesEP12NSDictionaryIP8NSStringPU25objcproto14NSSecureCoding11objc_objectEPU15__autoreleasingP7NSArrayIPS2_IS4_P8NSNumberEENS_30AVAudioSessionBatchSetStrategyEbb :548 (in AudioSession) 11 AudioSession 0x00000001c7753e58 __ZNK4avas6client11SessionCore20SetBatchPropertiesMXEP12NSDictionaryIP8NSStringPU25objcproto14NSSecureCoding11objc_objectE :92 (in AudioSession) 12 AudioSession 0x00000001c775179c __ZN4avas6client11SessionCore11setCategoryEP8NSStringS3_32AVAudioSessionRouteSharingPolicym :472 (in AudioSession) 13 AudioSession 0x00000001c7768f88 -[AVAudioSession setCategory:withOptions:error:] :68 (in AudioSession) 14 AlipayWallet 0x000000010140580c -[AVAudioSession(APMHook) apmhook_setCategory:withOptions:error:] APMHookAudioSession.m:35 (in AlipayWallet) 15 AlipayWallet 0x00000001014001a4 -[APMAudioSessionManager resume] APMAudioSessionManager.m:718 (in AlipayWallet) 16 libdispatch.dylib 0x00000001d63e4adc __dispatch_call_block_and_release :32 (in libdispatch.dylib) 17 libdispatch.dylib 0x00000001d63fe7ec __dispatch_client_callout :16 (in libdispatch.dylib) 18 libdispatch.dylib 0x00000001d63ed468 __dispatch_lane_serial_drain :740 (in libdispatch.dylib) 19 libdispatch.dylib 0x00000001d63edf44 __dispatch_lane_invoke :388 (in libdispatch.dylib) 20 libdispatch.dylib 0x00000001d63f83ec __dispatch_root_queue_drain_deferred_wlh :292 (in libdispatch.dylib) 21 libdispatch.dylib 0x00000001d63f7ce4 __dispatch_workloop_worker_thread :692 (in libdispatch.dylib) 22 libsystem_pthread.dylib 0x00000001f9fee3b8 __pthread_wqthread :292 (in libsystem_pthread.dylib) 23 libsystem_pthread.dylib 0x00000001f9fed8c0 _start_wqthread :8 (in libsystem_pthread.dylib)
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2
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0
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942
Activity
Feb ’26
Is there any way to control alarm volume independently when using AlarmKit?
Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Hi there! I’m currently building an alarm app on iOS using AlarmKit, and I’m running into a fundamental limitation around volume control. When using AlarmKit, alarm sounds are played at the system ringer volume. My goal is simple in concept: Allow users to set an alarm volume inside the app, and have the alarm sound play at that volume when triggered. However, AlarmKit does not provide any API to control or override the alarm volume. I’ve explored several approaches(AVSystemController, MPVolumeView...), but none achieved the desired result. Is there any supported or recommended way to achieve user-configurable alarm volume while still using AlarmKit? Any insights from developers who’ve shipped alarm apps, or from Apple engineers, would be greatly appreciated. Thanks in advance 🙏
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1
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0
Views
665
Activity
Jan ’26
Question about Apple Vision Pro audio input sampling rate for research
I am a graduate student conducting research in speech/audio signal processing and multimodal interaction. Apple Vision Pro is widely recognized as a multimodal interactive system supporting voice, eye, and gesture inputs. However, I could not find detailed specifications or documentation about the audio input sampling rate used by the device’s built-in microphone array when capturing user audio. Specifically, I would like to understand: What is the default audio input sampling rate (e.g., 16 kHz, 44.1 kHz, 48 kHz, etc.) for the Vision Pro’s microphones? When developing with visionOS / AVAudioSession / AVAudioEngine, is there a documented or recommended sampling rate for audio capture? Are there any best practices or settings for enabling high-quality voice capture on Vision Pro (especially for voice research tasks)? For context, my work involves voice processing, analysis, and possibly on-device real-time speech recognition. Any pointers to relevant APIs, documentation or examples (especially regarding audio capture buffer size or available formats on visionOS) would be very helpful. Thank you in advance! Best regards.
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0
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251
Activity
Jan ’26
AVAudioSession setActive(true) fails after phone call when app is in background
I’m seeing what appears to be an iOS audio-session issue that occurs only when a phone call happens while the app is in the background. API: AVAudioSession, AVAudioRecorder Background Modes: Audio enabled (UIBackgroundModes = audio) Category: .playAndRecord Microphone permission: granted Expected Behavior If the app is recording audio in the background and a phone call interrupts it: AVAudioSession.interruptionNotification(.began) fires Call ends AVAudioSession.interruptionNotification(.ended) fires App should be able to re-activate its audio session and resume or restart recording Apple documentation suggests this should be supported for background audio apps. Actual Behavior When the app is in the background and phone call is ended: AVAudioSession.interruptionNotification(.ended) does fire Attempting to reactivate the audio session always fails: Error Domain=NSOSStatusErrorDomain Code=560557684 ("!int") "Session activation failed" The session appears to remain permanently “interrupted” Retrying activation (with delays) does not help Recreating AVAudioRecorder does not help Reactivation works only after the app is opened again
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0
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226
Activity
Jan ’26
iOS React Native: Can two WebRTC stacks (Wazo & Jitsi) share media?
Hi everyone, I’m building a React Native iOS app where I’m integrating Wazo (native WebRTC) and Jitsi (WebView / WebRTC). Use case: Wazo is used to maintain a background call session (mainly signaling + audio keep-alive). Jitsi is used in the foreground for video calls. Problem: When Jitsi starts, it takes control of the microphone and camera. The Wazo call disconnects after ~5 minutes (likely due to media / audio session conflict). Even if Wazo audio/video is muted or tracks are disabled, the session still drops. My questions: Is it officially supported or recommended to run two WebRTC stacks (Wazo + Jitsi) simultaneously on iOS? Can Wazo stay connected without active audio/video tracks while Jitsi uses mic/camera? Is there a way to release Wazo media streams temporarily (but keep signaling alive) while Jitsi is loading or active? Are there any AVAudioSession / background mode limitations on iOS that make this impossible by design? If this is not supported, what is the recommended architecture (single WebRTC pipeline, switching media ownership, etc.)? Environment: iOS (React Native) Wazo SDK (native WebRTC) Jitsi Meet (WebView) CallKit + PushKit enabled Any guidance, documentation, or real-world experience would be greatly appreciated. Thanks in advance 🙏
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1
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423
Activity
Jan ’26
iPhone 14 Pro: External USB mic not available in AVAudioSession for call apps, but works in Voice Memos & Instagram Live
I’m facing a strange audio routing issue that seems specific to iPhone 14 Pro / Pro Max. I’m using LiveKit (WebRTC) in a React Native app, which uses AVAudioSession internally for audio capture (VoIP / call-style usage). 🔍 What’s happening: I’m using an external USB microphone. On these devices: iPhone 11 → ✅ USB mic works iPhone 13 → ✅ USB mic works iPhone 17 Pro → ✅ USB mic works iPhone 14 Pro Max → ❌ USB mic does NOT work On iPhone 14 Pro Max: The same USB mic: ✅ Works in Voice Memos ✅ Works in Instagram Live ❌ Does NOT appear as an input option in my app ❌ Does NOT work in WhatsApp / Instagram calls Also: In my app on iPhone 14 Pro Max, iOS does not show the audio input selector UI On iPhone 17 Pro, the same app and same build does show the selector and the USB mic works ⚙️ My audio session config ( LiveKit ): await AudioSession.setAppleAudioConfiguration({ audioCategory: 'playAndRecord', audioMode: 'default', audioCategoryOptions: ['allowBluetooth', 'defaultToSpeaker'], }); await AudioSession.startAudioSession(); ❓ My questions: Is this a known limitation or behavior specific to iPhone 14 Pro / Pro Max? Does iPhone 14 Pro have different audio routing rules for call / VoIP mode compared to other devices? Why does the same USB mic work in recording apps (Voice Memos, Instagram Live) but not in call-style apps (LiveKit, WhatsApp, Instagram call)? Is there any documented difference in AVAudioSession behavior on iPhone 14 Pro regarding external USB audio inputs?
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1
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0
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218
Activity
Jan ’26
After unholding CallKit, the audio does not restore.
In my application, I use CallKit and have supportsHolding = true set. During my phone call, another call comes in (e.g., GSM). I accept the incoming call and put the current call on hold. If I end the active call myself, everything is fine, and CallKit calls the method provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession). However, if the other party ends the call, the second call remains on hold. In the application, the user clicks on unhold, and I notify CallKit that the hold has ended. But in this case, the didActivate method is not called at all. If I try to activate the audio myself after unhold, I receive the error: Domain=NSOSStatusErrorDomain Code=561017449 "Session activation failed" UserInfo={NSLocalizedDescription=Session activation failed} AVAudioSessionErrorInsufficientPriority == NSOSStatusErrorDomain Code: 561017449 What needs to be done for CallKit to activate my audio?
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4
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2
Views
1.7k
Activity
Jan ’26