Dive into the technical aspects of audio on your device, including codecs, format support, and customization options.

Audio Documentation

Posts under Audio subtopic

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.longFormAudio and USB mic input
I am trying to stream audio from a USB input to a set of AirPlay speakers. I can get this to work to a single AirPlay speaker when I use .playAndRecord and don't use .longFormAudio in the AVAudioSession setup but I hear some audio glitches. I believe these glitches to be audio under-run at the speaker due to differences in clock rates, etc. As I understand the API, to get rid of the audio glitches, I need to use .longFormAudio to enable AirPlay2 and get the speaker to deal with tracking the audio sample timing and have the speaker do any re-sampling when the clocks drift. But if I turn on .longFormAudio, the API will not allow me to use .playAndRecord. Is there a way to get AirPlay2 re-timing behaviors and also enable mic input in the same IOS app?
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487
Aug ’26
Apple-supported alternative to MusicKit JS authorization for child accounts
I’m developing a dedicated children’s audio player using MusicKit JS. Ideally, a child would have access to their own Apple Music library and listening history while remaining managed through Family Sharing. Apple Developer Support confirmed that MusicKit cannot be authorized for an under-13 Apple Account due to age restrictions. Is there an Apple-supported alternative, such as parent authorization with access to a child’s library through any other SDK/API path?
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500
Aug ’26
Why isn’t Audio Output a per-app permission, like Microphone?
iOS already gives users a simple per-app Microphone permission: Settings → Apps → [App] → Microphone: On/Off Why isn’t there an equivalent permission in the other direction? Settings → Apps → [App] → Audio Output: On/Off This would solve a surprisingly common problem: I may deliberately be listening to Spotify, an audiobook or a podcast, then open another app which suddenly produces audio from an advertisement or autoplaying video. That audio may mix with, duck, or even interrupt what I actually chose to listen to. As I understand the current architecture, apps use AVAudioSession to describe how their audio should interact with other audio. But much of that policy is therefore controlled by the application producing the unwanted audio, rather than by the device owner. The simplest solution wouldn’t require a per-app mixer or complicated audio controls. Just one user-controlled permission: Allow Audio Output: On / Off When disabled, iOS would prevent that app from producing audible media output, while audio sessions belonging to other apps would continue normally. Conceptually, this seems very similar to the existing Microphone permission: Microphone: Can this app receive audio from my device? Audio Output: Can this app produce audio on my device? More advanced controls — per-app volume, permission to interrupt other audio, ducking policy, etc. — could potentially come later. But they aren’t necessary to solve the fundamental problem. I’m curious from an AVAudioSession perspective: Is there a technical reason why iOS could not enforce an OS-level per-app Audio Output permission in the same way it already enforces Microphone access? And if there isn’t, would others find this useful?
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443
Aug ’26
Fetch tracks from a playlist
If an app allows people to create a playlist and add more songs to that created playlist, it would make sense to guard them from accidentally adding the same song to the playlist more than once. In this code, even though it is successfully receiving the existing playlist from the request, its tracks and entries always show as nil even when there are songs in the playlist. Any suggestions for how to guard against adding duplicates to a playlist? Thank you! var request = MusicLibraryRequest<Playlist>() request.filter(matching: \.name, equalTo: "AppGeneratedPlaylist") let response = try await request.response() if let existingPlaylist = response.items.first { if let tracks = existingPlaylist.entries, tracks.contains(where: { $0.id == song.id }) { print("Song is already in the playlist, so don't add again") return } else { try await MusicLibrary.shared.add(song, to: existingPlaylist) print("Added song to existing playlist: \(existingPlaylist.name)") print("Count of tracks: \(existingPlaylist.tracks?.count)") print("Count of entries: \(existingPlaylist.entries?.count)") print("Current tracks: \(existingPlaylist.tracks?.map(\.id))") print("Current entries: \(existingPlaylist.entries?.map(\.id))") } }
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781
Aug ’26
Native WebRTC remote audio stops after ~1 hour while Safari still plays the same stream
Hello, I am developing BROXMEDIA Intercom, an iOS intercom application for live audiovisual production. The app uses a native Swift audio plugin, Google WebRTC, AVAudioSession, and a Capacitor user interface. The current TestFlight version is 2.0, build 17. Environment: iPhone 16 Pro Max iOS 26.5.2 TestFlight internal build AVAudioSession category: playAndRecord AVAudioSession mode: voiceChat Background audio capability enabled Bidirectional WebRTC audio between a web browser and the native iOS app Observed behavior: A remote web browser publishes WebRTC audio. The native iOS app receives and plays the audio correctly for approximately one hour. Wi-Fi disconnection/reconnection and airplane mode on/off initially recover correctly. After the prolonged session, the native app stops playing the remote audio. Signaling and participant presence remain connected. The remote participant is still shown as speaking. Completely closing and reopening the native app does not recover the remote audio. Safari on the same iPhone, connected to the same room and network, can still hear the same remote transmission. Restarting the remote web publication usually causes the native app to receive audio again. This suggests that the remote publication, network connection, signaling server, and device audio hardware are still operational when the native route fails. We are investigating whether: AVAudioSession or the underlying WebRTC audio unit has stopped rendering; the native RTCPeerConnection retains a stale receiver or audio track; inbound RTP has stopped even though the peer remains connected; an interruption, route change, or media-services reset has not been fully recovered. Our current recovery logic checks the peer connection state and whether a remote audio track object exists. However, we do not yet continuously verify that inbound RTP packets or bytes are increasing for each participant. Questions: Can AVAudioSession or its underlying audio unit stop rendering audio while RTCPeerConnection signaling remains connected? Which AVAudioSession or audio-unit callbacks should be monitored to distinguish an iOS audio-session failure from a WebRTC receiver or inbound-RTP failure? After AVAudioSession.mediaServicesWereResetNotification, should an app recreate the complete WebRTC audio engine, or is reactivating AVAudioSession normally sufficient? Is monitoring inbound RTP progression and audio energy the recommended way to detect a remote audio track that still exists but is no longer delivering usable audio? Are there any known considerations for prolonged bidirectional VoIP-style audio using playAndRecord, voiceChat, and background audio? We can add diagnostic logging and provide a Feedback Assistant report with sysdiagnose if the problem is reproduced again. Thank you.
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399
Aug ’26
SFSpeechRecognizer is unavailable or fails to initialize on iOS 26.4 and 26.5 Simulators
I am testing SFSpeechRecognizer using the en_US locale. When the iPhone Simulator’s system language is set to Japanese, SFSpeechRecognizer.isAvailable returns false for en_US, so speech recognition is unavailable. As far as I have tested, this issue does not occur on iOS Simulator 26.2 or earlier. Is this a Simulator-specific issue, or is it a behavior change that could also occur on physical devices? Has any additional setup become necessary to use speech recognition in Simulator? I then changed the iPhone Simulator’s system language to English. After doing so, SFSpeechRecognizer.isAvailable returned true for en_US. However, starting a recognition task still failed immediately with kLSRErrorDomain Code=300, “Failed to initialize recognizer.” The following error was returned: Error Domain=kLSRErrorDomain Code=300 "Failed to initialize recognizer" UserInfo={ NSLocalizedDescription=Failed to initialize recognizer, NSUnderlyingError={ Error Domain=kLSRErrorDomain Code=300 "Failed to create recognizer from=/Users/<USERNAME>/Library/Developer/CoreSimulator/Devices/<DEVICE-UUID>/data/private/var/MobileAsset/AssetsV2/com_apple_MobileAsset_UAF_Siri_Understanding/purpose_auto/ c079bfa6b8856202dc8cb2135fef3b06229ced6e.asset/AssetData/mini.json" UserInfo={ NSLocalizedDescription=Failed to create recognizer from=/Users/<USERNAME>/Library/Developer/CoreSimulator/Devices/<DEVICE-UUID>/data/private/var/MobileAsset/AssetsV2/com_apple_MobileAsset_UAF_Siri_Understanding/purpose_auto/ c079bfa6b8856202dc8cb2135fef3b06229ced6e.asset/AssetData/mini.json } } } I have not observed either of these issues on iOS Simulator 26.2 or earlier: With the Simulator language set to Japanese, the en_US recognizer does not become unavailable. When SFSpeechRecognizer.isAvailable is true, recognition does not fail with kLSRErrorDomain Code=300. Environment Xcode: 26.6 (17F113) iOS Simulator 26.5 (23F77), iPhone 17 (A3258J/A) iOS Simulator 26.4 (23E244), iPhone 17 (A3258J/A)
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1k
Aug ’26
VPIO Audio Ducking
Hey y'all, I'm new here and in the process of building some audio software. I'm hitting a roadblock trying to incorporate VPIO into audio playback states without it ducking what's currently playing in my DAW. I have a few questions: Can VPIO other-audio ducking be completely disabled on macOS, beyond fixed/minimum? Minimum is not enough for professional audio environments. Is attenuation of an unrelated application routed through a different Core Audio output device expected? Is split-device VPIO—built-in microphone input with Apollo/Universal Audio output—supported? Why can AVAudioEngine.start() succeed while the engine remains stopped and immediately emits a configuration-change notification? Thanks for any insight into this!
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921
Jul ’26
AVRoutePickerView's presented route list is automatically dismissed when CXProvider reports the call as connected (`reportOutgoingCall(with:connectedAt:)`)
Hi, I want my user to be able to change their audio output device while calling someone, even before the call is established. But I've run into an issue combining CallKit and AVRoutePickerView. On iOS 26 (Xcode 26.5, tested on iPhone 13 Mini): when my AVRoutePickerView's route list is presented while my call is still connecting (not yet established), the presented list is automatically dismissed the moment the app reports the call as connected via CXProvider.reportOutgoingCall(with:connectedAt:). That doesn't seem natural to me — it should stay open, since the user is actively interacting with unrelated system UI at that moment. This happens even when nothing about the AVAudioSession itself changes: no category change, no route change, no didActivate/didDeactivate callback fires around that time. The dismissal is caused by the CallKit "connected" state transition itself, but I don't know why, or whether it's intentional. Steps to reproduce (sample project below): Tap "Start Fake Call". Within 5 seconds, tap the small route picker button and leave its list open. Wait — at t+5s the app reports the call connected via reportOutgoingCall(connectedAt:), and the list closes itself right after. Is this normal? And is there an official, CallKit-sanctioned way to report a call's connected state without this side effect — some way to keep the route picker stable across that transition? The two workarounds I've found both have real downsides: Calling reportOutgoingCall(connectedAt:) at the very start of the call, before the callee has actually answered , but then CallKit no longer reflects the real call state (Recents/duration would include ringing time, and calls that are never answered would still show as "connected"). Disabling audio device selection entirely until the call is established... works, but hurts the user experience, since users may want to switch output before the call connects. Here's the minimal reproduction: import CallKit import SwiftUI struct ContentView: View { @StateObject private var demo = CallKitDemo() var body: some View { VStack(spacing: 24) { Text(demo.statusText) .font(.system(.body, design: .monospaced)) .multilineTextAlignment(.center) Button("Start Fake Call") { demo.startFakeCall() } .disabled(demo.isCallInProgress) RoutePickerView() .frame(width: 60, height: 60) } .padding() } } private struct RoutePickerView: UIViewRepresentable { func makeUIView(context: Context) -> AVRoutePickerView { let picker = AVRoutePickerView() picker.delegate = context.coordinator return picker } func updateUIView(_ uiView: AVRoutePickerView, context: Context) {} func makeCoordinator() -> Coordinator { Coordinator() } final class Coordinator: NSObject, AVRoutePickerViewDelegate { func routePickerViewWillBeginPresentingRoutes(_ routePickerView: AVRoutePickerView) { print("[REPRO]", Date(), "picker WILL present routes") } func routePickerViewDidEndPresentingRoutes(_ routePickerView: AVRoutePickerView) { print("[REPRO]", Date(), "picker DID end presenting routes <- dismissed here") } } } @MainActor final class CallKitDemo: NSObject, ObservableObject { @Published var statusText = "Idle" @Published var isCallInProgress = false private let provider: CXProvider = { let configuration = CXProviderConfiguration() configuration.supportsVideo = false configuration.maximumCallGroups = 1 configuration.maximumCallsPerCallGroup = 1 configuration.supportedHandleTypes = [.generic] return CXProvider(configuration: configuration) }() private let callController = CXCallController() private var currentCallUUID: UUID? override init() { super.init() provider.setDelegate(self, queue: nil) } func startFakeCall() { let uuid = UUID() currentCallUUID = uuid isCallInProgress = true statusText = "Requesting CXStartCallAction..." let handle = CXHandle(type: .generic, value: "repro-call") let startAction = CXStartCallAction(call: uuid, handle: handle) callController.request(CXTransaction(action: startAction)) { error in if let error { print("[REPRO]", Date(), "CXStartCallAction request failed:", error) } } DispatchQueue.main.asyncAfter(deadline: .now() + 5) { [weak self] in guard let self, currentCallUUID == uuid else { return } print("[REPRO]", Date(), "reportOutgoingCall(connectedAt:)") statusText = "Reported connected at t+5s" provider.reportOutgoingCall(with: uuid, connectedAt: Date()) } DispatchQueue.main.asyncAfter(deadline: .now() + 8) { [weak self] in guard let self, currentCallUUID == uuid else { return } callController.request(CXTransaction(action: CXEndCallAction(call: uuid))) { _ in } currentCallUUID = nil isCallInProgress = false statusText = "Call ended" } } } extension CallKitDemo: CXProviderDelegate { func providerDidReset(_ provider: CXProvider) {} func provider(_ provider: CXProvider, perform action: CXStartCallAction) { action.fulfill() } func provider(_ provider: CXProvider, perform action: CXEndCallAction) { action.fulfill() } func provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession) { print("[REPRO]", Date(), "didActivate") } func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) { print("[REPRO]", Date(), "didDeactivate") } } Thanks for your help !
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946
Jul ’26
_MPRemoteCommandEventDispatch crashes on iOS 26.x devices.
I'm seeing crashes in _MPRemoteCommandEventDispatch on iOS 26.x devices in 3 apps. According to Bugsnag logs they are: NSInternalInconsistencyException: event dispatch <_MPRemoteCommandEventDispatch: <MPRemoteCommandEvent: 0x11c049500 commandID=THV0 command=<MPRemoteCommand: 0x109ad1ea0 type=Play (0) enabled=YES handlers=[0x109b6a310]> sourceID=(null) ([HostedRoutingSessionDataSource] handleControlSendingCommand<2W5E>)> state:201> deallocated without calling continuation I attached a log from Xcode organizer matching Bugsnag crash. mpr_remote_command_event.crash When I set the brakpoint on the -[_MPRemoteCommandEventDispatch dealloc] I can see it it's hit every time I tap play or pause on locked screen play button. Thread 0 Crashed: 0 libsystem_kernel.dylib 0x00000002370420cc __pthread_kill + 8 (:-1) 1 libsystem_pthread.dylib 0x00000001e975c810 pthread_kill + 268 (pthread.c:1721) 2 libsystem_c.dylib 0x0000000198f8ff64 abort + 124 (abort.c:122) 3 libc++abi.dylib 0x000000018a7cf808 __abort_message + 132 (abort_message.cpp:66) 4 libc++abi.dylib 0x000000018a7be484 demangling_terminate_handler() + 304 (cxa_default_handlers.cpp:76) 5 libobjc.A.dylib 0x000000018a6cff78 _objc_terminate() + 156 (objc-exception.mm:496) 6 xxxxxxxxxxxxxx 0x00000001003a7db8 CPPExceptionTerminate() + 416 (BSG_KSCrashSentry_CPPException.mm:156) 7 libc++abi.dylib 0x000000018a7cebdc std::__terminate(void (*)()) + 16 (cxa_handlers.cpp:59) 8 libc++abi.dylib 0x000000018a7ceb80 std::terminate() + 108 (cxa_handlers.cpp:88) 9 CoreFoundation 0x000000018d7341c4 __CFRunLoopPerCalloutARPEnd + 256 (CFRunLoop.c:769) 10 CoreFoundation 0x000000018d70bb5c __CFRunLoopRun + 1976 (CFRunLoop.c:3179) 11 CoreFoundation 0x000000018d70aa6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462) 12 GraphicsServices 0x000000022e31c498 GSEventRunModal + 120 (GSEvent.c:2049) 13 UIKitCore 0x00000001930ceba4 -[UIApplication _run] + 792 (UIApplication.m:3902) 14 UIKitCore 0x0000000193077a78 UIApplicationMain + 336 (UIApplication.m:5577) 15 xxxxxxxxxxxxxx 0x00000001000c0134 main + 308 (main.swift:15) 16 dyld 0x000000018a722e28 start + 7116 (dyldMain.cpp:1477) Is the crash happening when the app is being terminated? Thank you!
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2.5k
Jul ’26
Can an iOS app analyze audio being played by another app?
Hello, I'm in the early planning stages of an iOS app and I'm trying to determine what's technically possible before designing around assumptions. Is it possible for a third-party iOS app, with the user's permission, to access or analyze audio that is being played by another app (for example Apple Podcasts, Spotify, Audible, or YouTube) in real time? Or is microphone input the only supported way for an app to analyze audio that is audible in the user's environment? I'm not asking about recording the screen or capturing video. I'm specifically trying to understand whether another app's audio output is ever available to third-party apps, or whether iOS intentionally isolates apps from each other's audio. If the answer depends on the audio source (for example Apple Podcasts versus Spotify versus audio coming through the microphone), I'd appreciate understanding those distinctions as well. Thank you.
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473
Jul ’26
CarPlay audio continues playing for approximately one second after the music is paused.
When my app is connected to CarPlay and music is playing, pausing playback from the device updates the playback state immediately. However, the audio continues to play for approximately one second before stopping. This issue only occurs with wireless CarPlay; playback pauses immediately with wired CarPlay. Is this expected behavior?
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526
Jul ’26
MusicKit JS authorize() returns AUTHORIZATION_ERROR "Unauthorized" (no Music User Token) — catalog works
Hi all — hoping someone has hit this. Our MusicKit JS (v3) web app calls authorize() and it rejects with AUTHORIZATION_ERROR / "Unauthorized" (no Music User Token is issued), even though the same developer token returns HTTP 200 for catalog requests (/v1/catalog/us/search) — so the token itself is valid. Setup (all verified): MusicKit JS v3 from js-cdn.music.apple.com/musickit/v3/musickit.js; MusicKit.configure() succeeds, storefront resolves to "us". Developer token is ES256, valid, and includes the origin claim for our exact site origin. Our MusicKit key is enabled for Media Services and tied to a Media ID that has MusicKit enabled. Referrer-Policy: strict-origin-when-cross-origin. Repro: sign in with an active Apple Music subscriber and tap Allow -> authorize() rejects. Reproduces for two subscriber Apple IDs, in Chrome and Edge, with third-party cookies allowed. Error object: { name: "AUTHORIZATION_ERROR", message: "Unauthorized", isMKError: true }, thrown inside musickit.js during the authorize() flow. The served MusicKit build is a prerelease (3.2526.0-prerelease.x). We've ruled out the usual suspects on our side (origin claim, referrer policy, token validity, API version, cookies, and portal provisioning). Has anyone resolved this, or is there an additional server-side enablement needed for a team/Media ID to issue web user tokens? Also filed as FB23587284. Thanks!
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541
Jul ’26
AVPlayer Reverse Audio Scrubbing?
Hey all, here seeking some perspective. I have an audio player app on macOS built on top of AVPlayer, I want to add the ability to scrub the audio, and hear the audio frames based on the playhead's position whether going forwards or backwards. When going backwards, the audio frame should be played in reverse as well. The audio tracks live online and are streamed. I tried playing with AVPlayer.rate, but the time pitch algos built in (.spectral, .varispeed, .timeDomain) all only guarantee up to 32x rate decoding accuracy. So technically, if the user scrubs fast enough, the audio rendered would not necessarily match the playhead's position. My current solution that works is to cache the raw audio bytes and play the appropriate frame when the user starts scrubbing. I decode the audio data manually using AudioToolbox's AudioFileOpenWithCallbacks into an AVAudioPCMBuffer, then pass it into AVAudioEngine+AVAudioPlayerNode combo. The problem with that is that means I need to cache this audio data myself (remember this is a stream), and since I don't have access to AVPlayer's own cache I need to also download it myself... which means two downloads for the same track which is less than ideal. This lead me to take it a step further and hijack AVPlayer's download process by implementing AVAssetResourceLoaderDelegate, that way AVPlayer and my audio scrubbing cache are both fed from the same source. Now... I feel like I went down a bit of a rabbit hole here. At the end of the day I simply want accurate audio scrubbing in both directions, while keeping in mind I want the audio snippets to play in reverse when the user goes backwards. Is there really no way to do this that's more "vanilla"? Am I missing something obvious? Genuinely open to any and all suggestions. Thanks.
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852
Jul ’26
Is preview-only playback (no user authentication) permitted for a web game?
I'm building a free web-based music trivia game (guess the release year of a song). I'd like to use the Apple Music API in the following way and want to confirm it complies with the Apple Music API / MusicKit terms: The app requests only 30-second preview clips (previews[].url from the Catalog API), played through a standard HTML element. No user ever signs in with an Apple ID — there is no Music User Token; only my developer token is used, server-side, to query the catalog. The app is free, does not gate playback behind any payment, and displays "Music previews via Apple Music" attribution. Full-track playback and user subscriptions are not used at all. The Apple Music API terms describe the purpose as facilitating access to end users' Apple Music subscriptions — since a preview-only integration never touches a subscription, I want to make sure this usage is sanctioned before launching publicly. Is preview-only, unauthenticated playback of catalog previews permitted in this scenario?
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692
Jul ’26
CarPlay: iPhone media does not reliably resume after short SFSpeechRecognizer capture with AVAudioSession record/measurement
Post Title: CarPlay: iPhone-origin media does not reliably resume after short SFSpeechRecognizer capture Post Body: We are testing short, user-initiated speech recognition in a CarPlay driving-task app. The capture is started by an explicit button tap, lasts up to about 4 seconds, and uses SFSpeechRecognizer, SFSpeechAudioBufferRecognitionRequest, and AVAudioEngine. There is no wake word, no continuous recording, and no background listening. Test setup: iPhone: iPhone 17 iOS: 26.5.2 CarPlay: wireless Vehicle / head unit: Volkswagen Discover Media Also tested in a second vehicle with wireless CarPlay Media tested: Apple Music and online radio through CarPlay Also tested: vehicle DAB+ / normal car radio Observed behavior: Native speech recognition succeeds. Speech is recognized correctly. There is no loud playback through the vehicle speakers. During the short capture, the audio route changes to CarPlay / CarAudio input. After capture, vehicle DAB+ / normal car radio resumes correctly. iPhone-origin media, including Apple Music and online radio apps playing through CarPlay, does not reliably resume. In Apple Music, playback may appear to advance or change tracks, but no audio is actually played until the user intervenes. Online radio through CarPlay remains stopped after capture. This behavior was reproduced in two vehicles with wireless CarPlay. Current AVAudioSession configuration during capture: category: AVAudioSession.Category.record mode: AVAudioSession.Mode.measurement options: [.mixWithOthers] During capture, diagnostics show approximately: category: AVAudioSessionCategoryRecord mode: AVAudioSessionModeMeasurement inputNumberOfChannels: 1 outputNumberOfChannels: 0 currentRoute.inputs: CarPlay / CarAudio currentRoute.outputs: none After capture, the app stops and releases audio resources: Stops AVAudioEngine Removes the input tap Ends the recognition request Cancels the recognition task Calls setActive(false, options: [.notifyOthersOnDeactivation]) Restores a passive configuration using .ambient / .default Relevant Swift extract: try session.setCategory( .record, mode: .measurement, options: [.mixWithOthers] ) try session.setActive(true, options: []) if audioEngine.isRunning { audioEngine.stop() } audioEngine.inputNode.removeTap(onBus: 0) recognitionRequest?.endAudio() recognitionRequest = nil recognitionTask?.cancel() recognitionTask = nil try session.setActive( false, options: [.notifyOthersOnDeactivation] ) try session.setCategory(.ambient, mode: .default, options: []) Primary question: Is there a supported AVAudioSession / CarPlay / Speech configuration for short, user-initiated speech recognition in a CarPlay driving-task app that reliably allows previous iPhone-origin CarPlay media playback to resume after capture? Additional question: Is it expected that vehicle DAB+ / normal radio resumes correctly while iPhone-origin CarPlay media does not reliably resume after the same short recording session? Any guidance on the supported approach would be appreciated. Best regards, Guido
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351
Jul ’26
AVAudioEngine input tap intermittently delivers all-zero buffers — valid format, no error thrown
We have a long-form audio recording app built on AVAudioEngine. We install a tap on inputNode, accumulate the PCM buffers, and encode them to AAC in ~60-second chunks. Setup is essentially: let session = AVAudioSession.sharedInstance() try session.setCategory(.playAndRecord, mode: .default, options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP]) try session.setActive(true) let engine = AVAudioEngine() let input = engine.inputNode let format = input.inputFormat(forBus: 0) // valid, e.g. 48 kHz, 1 ch input.installTap(onBus: 0, bufferSize: 1024, format: format) { buffer, _ in // In the failure case, buffer.floatChannelData is entirely 0.0 // (accumulate + encode to AAC) } engine.prepare() try engine.start() Intermittently — and so far only reported from the field, never reproduced in normal testing — a recording comes out completely silent. When we decode the resulting AAC and inspect the raw PCM, every sample is exactly 0.0. The signature is very specific: The engine is running and the tap keeps firing for the full duration (normal number of buffers / full-length chunks). inputFormat is valid (sampleRate ≠ 0, e.g. 48 kHz). No error is thrown anywhere — setCategory, setActive, start(), and the tap callback all succeed. The PCM is literally all zeros (not low-level noise / room tone — exact 0.0). Two separate silent recordings decode to byte-identical AAC, confirming pure digital silence rather than corruption. So as far as our error handling, format checks, and tap-liveness are concerned, everything looks healthy — yet the microphone is delivering pure silence. One way we can reproduce it: recording while the iPhone is being driven via macOS iPhone Mirroring (the iPhone stays locked, the mic is effectively unavailable from the device, but our session still activates with a valid format and the tap fires zero-filled buffers for the whole recording — with no error at any point). What we've ruled out: microphone permission is granted; it's not truncation or short capture (full-length, full frame count); it's not our encoding step (the input buffers themselves are zero); it's not a quiet/obstructed mic (that would be low noise, not exact 0.0). We also found two existing threads describing what looks like the same symptom: https://developer.apple.com/forums/thread/834950 https://developer.apple.com/forums/thread/808072 Both of those are PushToTalk apps where the system activates the audio session, and an Apple engineer notes it may be related to a CallKit issue (r.157725305). For context on our side: we do use CallKit, but only CXCallObserver — purely to detect whether a phone call comes in while a recording is in progress, so we can pause and resume around it. We do not use CXProvider or PushToTalk, and we activate our own AVAudioSession ourselves with setActive(true). I'm trying to understand whether there are other scenarios or device states that could leave a running AVAudioEngine tap returning all-zero buffers like this, and whether this is the same underlying CallKit issue (r.157725305) from those threads . And since nothing throws an error, any guidance on how to detect this at runtime and recover from it would be really helpful.
0
0
736
Jul ’26
AVAudioEngine input tap intermittently delivers all-zero buffers — valid format, no error thrown
We have a long-form audio recording app built on AVAudioEngine. We install a tap on inputNode, accumulate the PCM buffers, and encode them to AAC in ~60-second chunks. Setup is essentially: let session = AVAudioSession.sharedInstance() try session.setCategory(.playAndRecord, mode: .default, options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP]) try session.setActive(true) let engine = AVAudioEngine() let input = engine.inputNode let format = input.inputFormat(forBus: 0) // valid, e.g. 48 kHz, 1 ch input.installTap(onBus: 0, bufferSize: 1024, format: format) { buffer, _ in // In the failure case, buffer.floatChannelData is entirely 0.0 // (accumulate + encode to AAC) } engine.prepare() try engine.start() Intermittently — and so far only reported from the field, never reproduced in normal testing — a recording comes out completely silent. When we decode the resulting AAC and inspect the raw PCM, every sample is exactly 0.0. The signature is very specific: The engine is running and the tap keeps firing for the full duration (normal number of buffers / full-length chunks). inputFormat is valid (sampleRate ≠ 0, e.g. 48 kHz). No error is thrown anywhere — setCategory, setActive, start(), and the tap callback all succeed. The PCM is literally all zeros (not low-level noise / room tone — exact 0.0). Two separate silent recordings decode to byte-identical AAC, confirming pure digital silence rather than corruption. So as far as our error handling, format checks, and tap-liveness are concerned, everything looks healthy — yet the microphone is delivering pure silence. One way we can reproduce it: recording while the iPhone is being driven via macOS iPhone Mirroring (the iPhone stays locked, the mic is effectively unavailable from the device, but our session still activates with a valid format and the tap fires zero-filled buffers for the whole recording — with no error at any point). What we've ruled out: microphone permission is granted; it's not truncation or short capture (full-length, full frame count); it's not our encoding step (the input buffers themselves are zero); it's not a quiet/obstructed mic (that would be low noise, not exact 0.0). Questions: What other device states or scenarios can cause a running AVAudioEngine input tap to deliver all-zero buffers with a valid format and no error? (e.g. another process/system feature holding the mic, Continuity Camera/Mic, CallKit/PushToTalk session ownership, etc.) Since this surfaces with no error and a valid format, what is the recommended way to detect it at runtime? Is monitoring the input level / PCM energy the only signal, or is there a supported API to know the input isn't actually live? What's the recommended recovery once detected — is a full session deactivate/reactivate re-handshake sufficient, or is recreating the engine required?
1
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575
Jun ’26
.longFormAudio and USB mic input
I am trying to stream audio from a USB input to a set of AirPlay speakers. I can get this to work to a single AirPlay speaker when I use .playAndRecord and don't use .longFormAudio in the AVAudioSession setup but I hear some audio glitches. I believe these glitches to be audio under-run at the speaker due to differences in clock rates, etc. As I understand the API, to get rid of the audio glitches, I need to use .longFormAudio to enable AirPlay2 and get the speaker to deal with tracking the audio sample timing and have the speaker do any re-sampling when the clocks drift. But if I turn on .longFormAudio, the API will not allow me to use .playAndRecord. Is there a way to get AirPlay2 re-timing behaviors and also enable mic input in the same IOS app?
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487
Activity
Aug ’26
Apple-supported alternative to MusicKit JS authorization for child accounts
I’m developing a dedicated children’s audio player using MusicKit JS. Ideally, a child would have access to their own Apple Music library and listening history while remaining managed through Family Sharing. Apple Developer Support confirmed that MusicKit cannot be authorized for an under-13 Apple Account due to age restrictions. Is there an Apple-supported alternative, such as parent authorization with access to a child’s library through any other SDK/API path?
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500
Activity
Aug ’26
Why isn’t Audio Output a per-app permission, like Microphone?
iOS already gives users a simple per-app Microphone permission: Settings → Apps → [App] → Microphone: On/Off Why isn’t there an equivalent permission in the other direction? Settings → Apps → [App] → Audio Output: On/Off This would solve a surprisingly common problem: I may deliberately be listening to Spotify, an audiobook or a podcast, then open another app which suddenly produces audio from an advertisement or autoplaying video. That audio may mix with, duck, or even interrupt what I actually chose to listen to. As I understand the current architecture, apps use AVAudioSession to describe how their audio should interact with other audio. But much of that policy is therefore controlled by the application producing the unwanted audio, rather than by the device owner. The simplest solution wouldn’t require a per-app mixer or complicated audio controls. Just one user-controlled permission: Allow Audio Output: On / Off When disabled, iOS would prevent that app from producing audible media output, while audio sessions belonging to other apps would continue normally. Conceptually, this seems very similar to the existing Microphone permission: Microphone: Can this app receive audio from my device? Audio Output: Can this app produce audio on my device? More advanced controls — per-app volume, permission to interrupt other audio, ducking policy, etc. — could potentially come later. But they aren’t necessary to solve the fundamental problem. I’m curious from an AVAudioSession perspective: Is there a technical reason why iOS could not enforce an OS-level per-app Audio Output permission in the same way it already enforces Microphone access? And if there isn’t, would others find this useful?
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443
Activity
Aug ’26
Fetch tracks from a playlist
If an app allows people to create a playlist and add more songs to that created playlist, it would make sense to guard them from accidentally adding the same song to the playlist more than once. In this code, even though it is successfully receiving the existing playlist from the request, its tracks and entries always show as nil even when there are songs in the playlist. Any suggestions for how to guard against adding duplicates to a playlist? Thank you! var request = MusicLibraryRequest<Playlist>() request.filter(matching: \.name, equalTo: "AppGeneratedPlaylist") let response = try await request.response() if let existingPlaylist = response.items.first { if let tracks = existingPlaylist.entries, tracks.contains(where: { $0.id == song.id }) { print("Song is already in the playlist, so don't add again") return } else { try await MusicLibrary.shared.add(song, to: existingPlaylist) print("Added song to existing playlist: \(existingPlaylist.name)") print("Count of tracks: \(existingPlaylist.tracks?.count)") print("Count of entries: \(existingPlaylist.entries?.count)") print("Current tracks: \(existingPlaylist.tracks?.map(\.id))") print("Current entries: \(existingPlaylist.entries?.map(\.id))") } }
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781
Activity
Aug ’26
How to hide route button `showsRouteButton = false` in `MPVolumeView` without deprecation warning?
MPVolumeView's showsRouteButton was deprecated (https://developer.apple.com/documentation/mediaplayer/mpvolumeview/showsroutebutton?language=objc). It's not clear how can we now hide this button without deprecation warning. The documentation is lacking. Please advise. Thank you!
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6
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1.2k
Activity
Aug ’26
Native WebRTC remote audio stops after ~1 hour while Safari still plays the same stream
Hello, I am developing BROXMEDIA Intercom, an iOS intercom application for live audiovisual production. The app uses a native Swift audio plugin, Google WebRTC, AVAudioSession, and a Capacitor user interface. The current TestFlight version is 2.0, build 17. Environment: iPhone 16 Pro Max iOS 26.5.2 TestFlight internal build AVAudioSession category: playAndRecord AVAudioSession mode: voiceChat Background audio capability enabled Bidirectional WebRTC audio between a web browser and the native iOS app Observed behavior: A remote web browser publishes WebRTC audio. The native iOS app receives and plays the audio correctly for approximately one hour. Wi-Fi disconnection/reconnection and airplane mode on/off initially recover correctly. After the prolonged session, the native app stops playing the remote audio. Signaling and participant presence remain connected. The remote participant is still shown as speaking. Completely closing and reopening the native app does not recover the remote audio. Safari on the same iPhone, connected to the same room and network, can still hear the same remote transmission. Restarting the remote web publication usually causes the native app to receive audio again. This suggests that the remote publication, network connection, signaling server, and device audio hardware are still operational when the native route fails. We are investigating whether: AVAudioSession or the underlying WebRTC audio unit has stopped rendering; the native RTCPeerConnection retains a stale receiver or audio track; inbound RTP has stopped even though the peer remains connected; an interruption, route change, or media-services reset has not been fully recovered. Our current recovery logic checks the peer connection state and whether a remote audio track object exists. However, we do not yet continuously verify that inbound RTP packets or bytes are increasing for each participant. Questions: Can AVAudioSession or its underlying audio unit stop rendering audio while RTCPeerConnection signaling remains connected? Which AVAudioSession or audio-unit callbacks should be monitored to distinguish an iOS audio-session failure from a WebRTC receiver or inbound-RTP failure? After AVAudioSession.mediaServicesWereResetNotification, should an app recreate the complete WebRTC audio engine, or is reactivating AVAudioSession normally sufficient? Is monitoring inbound RTP progression and audio energy the recommended way to detect a remote audio track that still exists but is no longer delivering usable audio? Are there any known considerations for prolonged bidirectional VoIP-style audio using playAndRecord, voiceChat, and background audio? We can add diagnostic logging and provide a Feedback Assistant report with sysdiagnose if the problem is reproduced again. Thank you.
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399
Activity
Aug ’26
SFSpeechRecognizer is unavailable or fails to initialize on iOS 26.4 and 26.5 Simulators
I am testing SFSpeechRecognizer using the en_US locale. When the iPhone Simulator’s system language is set to Japanese, SFSpeechRecognizer.isAvailable returns false for en_US, so speech recognition is unavailable. As far as I have tested, this issue does not occur on iOS Simulator 26.2 or earlier. Is this a Simulator-specific issue, or is it a behavior change that could also occur on physical devices? Has any additional setup become necessary to use speech recognition in Simulator? I then changed the iPhone Simulator’s system language to English. After doing so, SFSpeechRecognizer.isAvailable returned true for en_US. However, starting a recognition task still failed immediately with kLSRErrorDomain Code=300, “Failed to initialize recognizer.” The following error was returned: Error Domain=kLSRErrorDomain Code=300 "Failed to initialize recognizer" UserInfo={ NSLocalizedDescription=Failed to initialize recognizer, NSUnderlyingError={ Error Domain=kLSRErrorDomain Code=300 "Failed to create recognizer from=/Users/<USERNAME>/Library/Developer/CoreSimulator/Devices/<DEVICE-UUID>/data/private/var/MobileAsset/AssetsV2/com_apple_MobileAsset_UAF_Siri_Understanding/purpose_auto/ c079bfa6b8856202dc8cb2135fef3b06229ced6e.asset/AssetData/mini.json" UserInfo={ NSLocalizedDescription=Failed to create recognizer from=/Users/<USERNAME>/Library/Developer/CoreSimulator/Devices/<DEVICE-UUID>/data/private/var/MobileAsset/AssetsV2/com_apple_MobileAsset_UAF_Siri_Understanding/purpose_auto/ c079bfa6b8856202dc8cb2135fef3b06229ced6e.asset/AssetData/mini.json } } } I have not observed either of these issues on iOS Simulator 26.2 or earlier: With the Simulator language set to Japanese, the en_US recognizer does not become unavailable. When SFSpeechRecognizer.isAvailable is true, recognition does not fail with kLSRErrorDomain Code=300. Environment Xcode: 26.6 (17F113) iOS Simulator 26.5 (23F77), iPhone 17 (A3258J/A) iOS Simulator 26.4 (23E244), iPhone 17 (A3258J/A)
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1k
Activity
Aug ’26
Turn my iPhone to silent mode via Code (Swift)
Hi All,I am working on a project to turn my iPhone to silent mode via Code (Swift), Can someone ,plz, help to put on the right direction as I am very new to Xcode and Swift.Regards
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Activity
Jul ’26
VPIO Audio Ducking
Hey y'all, I'm new here and in the process of building some audio software. I'm hitting a roadblock trying to incorporate VPIO into audio playback states without it ducking what's currently playing in my DAW. I have a few questions: Can VPIO other-audio ducking be completely disabled on macOS, beyond fixed/minimum? Minimum is not enough for professional audio environments. Is attenuation of an unrelated application routed through a different Core Audio output device expected? Is split-device VPIO—built-in microphone input with Apollo/Universal Audio output—supported? Why can AVAudioEngine.start() succeed while the engine remains stopped and immediately emits a configuration-change notification? Thanks for any insight into this!
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921
Activity
Jul ’26
AVRoutePickerView's presented route list is automatically dismissed when CXProvider reports the call as connected (`reportOutgoingCall(with:connectedAt:)`)
Hi, I want my user to be able to change their audio output device while calling someone, even before the call is established. But I've run into an issue combining CallKit and AVRoutePickerView. On iOS 26 (Xcode 26.5, tested on iPhone 13 Mini): when my AVRoutePickerView's route list is presented while my call is still connecting (not yet established), the presented list is automatically dismissed the moment the app reports the call as connected via CXProvider.reportOutgoingCall(with:connectedAt:). That doesn't seem natural to me — it should stay open, since the user is actively interacting with unrelated system UI at that moment. This happens even when nothing about the AVAudioSession itself changes: no category change, no route change, no didActivate/didDeactivate callback fires around that time. The dismissal is caused by the CallKit "connected" state transition itself, but I don't know why, or whether it's intentional. Steps to reproduce (sample project below): Tap "Start Fake Call". Within 5 seconds, tap the small route picker button and leave its list open. Wait — at t+5s the app reports the call connected via reportOutgoingCall(connectedAt:), and the list closes itself right after. Is this normal? And is there an official, CallKit-sanctioned way to report a call's connected state without this side effect — some way to keep the route picker stable across that transition? The two workarounds I've found both have real downsides: Calling reportOutgoingCall(connectedAt:) at the very start of the call, before the callee has actually answered , but then CallKit no longer reflects the real call state (Recents/duration would include ringing time, and calls that are never answered would still show as "connected"). Disabling audio device selection entirely until the call is established... works, but hurts the user experience, since users may want to switch output before the call connects. Here's the minimal reproduction: import CallKit import SwiftUI struct ContentView: View { @StateObject private var demo = CallKitDemo() var body: some View { VStack(spacing: 24) { Text(demo.statusText) .font(.system(.body, design: .monospaced)) .multilineTextAlignment(.center) Button("Start Fake Call") { demo.startFakeCall() } .disabled(demo.isCallInProgress) RoutePickerView() .frame(width: 60, height: 60) } .padding() } } private struct RoutePickerView: UIViewRepresentable { func makeUIView(context: Context) -> AVRoutePickerView { let picker = AVRoutePickerView() picker.delegate = context.coordinator return picker } func updateUIView(_ uiView: AVRoutePickerView, context: Context) {} func makeCoordinator() -> Coordinator { Coordinator() } final class Coordinator: NSObject, AVRoutePickerViewDelegate { func routePickerViewWillBeginPresentingRoutes(_ routePickerView: AVRoutePickerView) { print("[REPRO]", Date(), "picker WILL present routes") } func routePickerViewDidEndPresentingRoutes(_ routePickerView: AVRoutePickerView) { print("[REPRO]", Date(), "picker DID end presenting routes <- dismissed here") } } } @MainActor final class CallKitDemo: NSObject, ObservableObject { @Published var statusText = "Idle" @Published var isCallInProgress = false private let provider: CXProvider = { let configuration = CXProviderConfiguration() configuration.supportsVideo = false configuration.maximumCallGroups = 1 configuration.maximumCallsPerCallGroup = 1 configuration.supportedHandleTypes = [.generic] return CXProvider(configuration: configuration) }() private let callController = CXCallController() private var currentCallUUID: UUID? override init() { super.init() provider.setDelegate(self, queue: nil) } func startFakeCall() { let uuid = UUID() currentCallUUID = uuid isCallInProgress = true statusText = "Requesting CXStartCallAction..." let handle = CXHandle(type: .generic, value: "repro-call") let startAction = CXStartCallAction(call: uuid, handle: handle) callController.request(CXTransaction(action: startAction)) { error in if let error { print("[REPRO]", Date(), "CXStartCallAction request failed:", error) } } DispatchQueue.main.asyncAfter(deadline: .now() + 5) { [weak self] in guard let self, currentCallUUID == uuid else { return } print("[REPRO]", Date(), "reportOutgoingCall(connectedAt:)") statusText = "Reported connected at t+5s" provider.reportOutgoingCall(with: uuid, connectedAt: Date()) } DispatchQueue.main.asyncAfter(deadline: .now() + 8) { [weak self] in guard let self, currentCallUUID == uuid else { return } callController.request(CXTransaction(action: CXEndCallAction(call: uuid))) { _ in } currentCallUUID = nil isCallInProgress = false statusText = "Call ended" } } } extension CallKitDemo: CXProviderDelegate { func providerDidReset(_ provider: CXProvider) {} func provider(_ provider: CXProvider, perform action: CXStartCallAction) { action.fulfill() } func provider(_ provider: CXProvider, perform action: CXEndCallAction) { action.fulfill() } func provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession) { print("[REPRO]", Date(), "didActivate") } func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) { print("[REPRO]", Date(), "didDeactivate") } } Thanks for your help !
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946
Activity
Jul ’26
_MPRemoteCommandEventDispatch crashes on iOS 26.x devices.
I'm seeing crashes in _MPRemoteCommandEventDispatch on iOS 26.x devices in 3 apps. According to Bugsnag logs they are: NSInternalInconsistencyException: event dispatch <_MPRemoteCommandEventDispatch: <MPRemoteCommandEvent: 0x11c049500 commandID=THV0 command=<MPRemoteCommand: 0x109ad1ea0 type=Play (0) enabled=YES handlers=[0x109b6a310]> sourceID=(null) ([HostedRoutingSessionDataSource] handleControlSendingCommand<2W5E>)> state:201> deallocated without calling continuation I attached a log from Xcode organizer matching Bugsnag crash. mpr_remote_command_event.crash When I set the brakpoint on the -[_MPRemoteCommandEventDispatch dealloc] I can see it it's hit every time I tap play or pause on locked screen play button. Thread 0 Crashed: 0 libsystem_kernel.dylib 0x00000002370420cc __pthread_kill + 8 (:-1) 1 libsystem_pthread.dylib 0x00000001e975c810 pthread_kill + 268 (pthread.c:1721) 2 libsystem_c.dylib 0x0000000198f8ff64 abort + 124 (abort.c:122) 3 libc++abi.dylib 0x000000018a7cf808 __abort_message + 132 (abort_message.cpp:66) 4 libc++abi.dylib 0x000000018a7be484 demangling_terminate_handler() + 304 (cxa_default_handlers.cpp:76) 5 libobjc.A.dylib 0x000000018a6cff78 _objc_terminate() + 156 (objc-exception.mm:496) 6 xxxxxxxxxxxxxx 0x00000001003a7db8 CPPExceptionTerminate() + 416 (BSG_KSCrashSentry_CPPException.mm:156) 7 libc++abi.dylib 0x000000018a7cebdc std::__terminate(void (*)()) + 16 (cxa_handlers.cpp:59) 8 libc++abi.dylib 0x000000018a7ceb80 std::terminate() + 108 (cxa_handlers.cpp:88) 9 CoreFoundation 0x000000018d7341c4 __CFRunLoopPerCalloutARPEnd + 256 (CFRunLoop.c:769) 10 CoreFoundation 0x000000018d70bb5c __CFRunLoopRun + 1976 (CFRunLoop.c:3179) 11 CoreFoundation 0x000000018d70aa6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462) 12 GraphicsServices 0x000000022e31c498 GSEventRunModal + 120 (GSEvent.c:2049) 13 UIKitCore 0x00000001930ceba4 -[UIApplication _run] + 792 (UIApplication.m:3902) 14 UIKitCore 0x0000000193077a78 UIApplicationMain + 336 (UIApplication.m:5577) 15 xxxxxxxxxxxxxx 0x00000001000c0134 main + 308 (main.swift:15) 16 dyld 0x000000018a722e28 start + 7116 (dyldMain.cpp:1477) Is the crash happening when the app is being terminated? Thank you!
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Activity
Jul ’26
Can an iOS app analyze audio being played by another app?
Hello, I'm in the early planning stages of an iOS app and I'm trying to determine what's technically possible before designing around assumptions. Is it possible for a third-party iOS app, with the user's permission, to access or analyze audio that is being played by another app (for example Apple Podcasts, Spotify, Audible, or YouTube) in real time? Or is microphone input the only supported way for an app to analyze audio that is audible in the user's environment? I'm not asking about recording the screen or capturing video. I'm specifically trying to understand whether another app's audio output is ever available to third-party apps, or whether iOS intentionally isolates apps from each other's audio. If the answer depends on the audio source (for example Apple Podcasts versus Spotify versus audio coming through the microphone), I'd appreciate understanding those distinctions as well. Thank you.
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473
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Jul ’26
CarPlay audio continues playing for approximately one second after the music is paused.
When my app is connected to CarPlay and music is playing, pausing playback from the device updates the playback state immediately. However, the audio continues to play for approximately one second before stopping. This issue only occurs with wireless CarPlay; playback pauses immediately with wired CarPlay. Is this expected behavior?
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526
Activity
Jul ’26
Phonetic pronunciations are broken in iOS 27 beta 1
Playing the same IPA pronunciations using AVSpeechSynthesisIPANotationAttribute on iOS 26.5 and iOS 27.0 beta 1 yield very different results. It appears as if iOS is ignoring the IPA symbols. FB23041286 Sample app is here: https://github.com/ryanlintott/SpeechSynthesisIPAExample
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2
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578
Activity
Jul ’26
MusicKit JS authorize() returns AUTHORIZATION_ERROR "Unauthorized" (no Music User Token) — catalog works
Hi all — hoping someone has hit this. Our MusicKit JS (v3) web app calls authorize() and it rejects with AUTHORIZATION_ERROR / "Unauthorized" (no Music User Token is issued), even though the same developer token returns HTTP 200 for catalog requests (/v1/catalog/us/search) — so the token itself is valid. Setup (all verified): MusicKit JS v3 from js-cdn.music.apple.com/musickit/v3/musickit.js; MusicKit.configure() succeeds, storefront resolves to "us". Developer token is ES256, valid, and includes the origin claim for our exact site origin. Our MusicKit key is enabled for Media Services and tied to a Media ID that has MusicKit enabled. Referrer-Policy: strict-origin-when-cross-origin. Repro: sign in with an active Apple Music subscriber and tap Allow -> authorize() rejects. Reproduces for two subscriber Apple IDs, in Chrome and Edge, with third-party cookies allowed. Error object: { name: "AUTHORIZATION_ERROR", message: "Unauthorized", isMKError: true }, thrown inside musickit.js during the authorize() flow. The served MusicKit build is a prerelease (3.2526.0-prerelease.x). We've ruled out the usual suspects on our side (origin claim, referrer policy, token validity, API version, cookies, and portal provisioning). Has anyone resolved this, or is there an additional server-side enablement needed for a team/Media ID to issue web user tokens? Also filed as FB23587284. Thanks!
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541
Activity
Jul ’26
AVPlayer Reverse Audio Scrubbing?
Hey all, here seeking some perspective. I have an audio player app on macOS built on top of AVPlayer, I want to add the ability to scrub the audio, and hear the audio frames based on the playhead's position whether going forwards or backwards. When going backwards, the audio frame should be played in reverse as well. The audio tracks live online and are streamed. I tried playing with AVPlayer.rate, but the time pitch algos built in (.spectral, .varispeed, .timeDomain) all only guarantee up to 32x rate decoding accuracy. So technically, if the user scrubs fast enough, the audio rendered would not necessarily match the playhead's position. My current solution that works is to cache the raw audio bytes and play the appropriate frame when the user starts scrubbing. I decode the audio data manually using AudioToolbox's AudioFileOpenWithCallbacks into an AVAudioPCMBuffer, then pass it into AVAudioEngine+AVAudioPlayerNode combo. The problem with that is that means I need to cache this audio data myself (remember this is a stream), and since I don't have access to AVPlayer's own cache I need to also download it myself... which means two downloads for the same track which is less than ideal. This lead me to take it a step further and hijack AVPlayer's download process by implementing AVAssetResourceLoaderDelegate, that way AVPlayer and my audio scrubbing cache are both fed from the same source. Now... I feel like I went down a bit of a rabbit hole here. At the end of the day I simply want accurate audio scrubbing in both directions, while keeping in mind I want the audio snippets to play in reverse when the user goes backwards. Is there really no way to do this that's more "vanilla"? Am I missing something obvious? Genuinely open to any and all suggestions. Thanks.
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852
Activity
Jul ’26
Is preview-only playback (no user authentication) permitted for a web game?
I'm building a free web-based music trivia game (guess the release year of a song). I'd like to use the Apple Music API in the following way and want to confirm it complies with the Apple Music API / MusicKit terms: The app requests only 30-second preview clips (previews[].url from the Catalog API), played through a standard HTML element. No user ever signs in with an Apple ID — there is no Music User Token; only my developer token is used, server-side, to query the catalog. The app is free, does not gate playback behind any payment, and displays "Music previews via Apple Music" attribution. Full-track playback and user subscriptions are not used at all. The Apple Music API terms describe the purpose as facilitating access to end users' Apple Music subscriptions — since a preview-only integration never touches a subscription, I want to make sure this usage is sanctioned before launching publicly. Is preview-only, unauthenticated playback of catalog previews permitted in this scenario?
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692
Activity
Jul ’26
CarPlay: iPhone media does not reliably resume after short SFSpeechRecognizer capture with AVAudioSession record/measurement
Post Title: CarPlay: iPhone-origin media does not reliably resume after short SFSpeechRecognizer capture Post Body: We are testing short, user-initiated speech recognition in a CarPlay driving-task app. The capture is started by an explicit button tap, lasts up to about 4 seconds, and uses SFSpeechRecognizer, SFSpeechAudioBufferRecognitionRequest, and AVAudioEngine. There is no wake word, no continuous recording, and no background listening. Test setup: iPhone: iPhone 17 iOS: 26.5.2 CarPlay: wireless Vehicle / head unit: Volkswagen Discover Media Also tested in a second vehicle with wireless CarPlay Media tested: Apple Music and online radio through CarPlay Also tested: vehicle DAB+ / normal car radio Observed behavior: Native speech recognition succeeds. Speech is recognized correctly. There is no loud playback through the vehicle speakers. During the short capture, the audio route changes to CarPlay / CarAudio input. After capture, vehicle DAB+ / normal car radio resumes correctly. iPhone-origin media, including Apple Music and online radio apps playing through CarPlay, does not reliably resume. In Apple Music, playback may appear to advance or change tracks, but no audio is actually played until the user intervenes. Online radio through CarPlay remains stopped after capture. This behavior was reproduced in two vehicles with wireless CarPlay. Current AVAudioSession configuration during capture: category: AVAudioSession.Category.record mode: AVAudioSession.Mode.measurement options: [.mixWithOthers] During capture, diagnostics show approximately: category: AVAudioSessionCategoryRecord mode: AVAudioSessionModeMeasurement inputNumberOfChannels: 1 outputNumberOfChannels: 0 currentRoute.inputs: CarPlay / CarAudio currentRoute.outputs: none After capture, the app stops and releases audio resources: Stops AVAudioEngine Removes the input tap Ends the recognition request Cancels the recognition task Calls setActive(false, options: [.notifyOthersOnDeactivation]) Restores a passive configuration using .ambient / .default Relevant Swift extract: try session.setCategory( .record, mode: .measurement, options: [.mixWithOthers] ) try session.setActive(true, options: []) if audioEngine.isRunning { audioEngine.stop() } audioEngine.inputNode.removeTap(onBus: 0) recognitionRequest?.endAudio() recognitionRequest = nil recognitionTask?.cancel() recognitionTask = nil try session.setActive( false, options: [.notifyOthersOnDeactivation] ) try session.setCategory(.ambient, mode: .default, options: []) Primary question: Is there a supported AVAudioSession / CarPlay / Speech configuration for short, user-initiated speech recognition in a CarPlay driving-task app that reliably allows previous iPhone-origin CarPlay media playback to resume after capture? Additional question: Is it expected that vehicle DAB+ / normal radio resumes correctly while iPhone-origin CarPlay media does not reliably resume after the same short recording session? Any guidance on the supported approach would be appreciated. Best regards, Guido
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351
Activity
Jul ’26
AVAudioEngine input tap intermittently delivers all-zero buffers — valid format, no error thrown
We have a long-form audio recording app built on AVAudioEngine. We install a tap on inputNode, accumulate the PCM buffers, and encode them to AAC in ~60-second chunks. Setup is essentially: let session = AVAudioSession.sharedInstance() try session.setCategory(.playAndRecord, mode: .default, options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP]) try session.setActive(true) let engine = AVAudioEngine() let input = engine.inputNode let format = input.inputFormat(forBus: 0) // valid, e.g. 48 kHz, 1 ch input.installTap(onBus: 0, bufferSize: 1024, format: format) { buffer, _ in // In the failure case, buffer.floatChannelData is entirely 0.0 // (accumulate + encode to AAC) } engine.prepare() try engine.start() Intermittently — and so far only reported from the field, never reproduced in normal testing — a recording comes out completely silent. When we decode the resulting AAC and inspect the raw PCM, every sample is exactly 0.0. The signature is very specific: The engine is running and the tap keeps firing for the full duration (normal number of buffers / full-length chunks). inputFormat is valid (sampleRate ≠ 0, e.g. 48 kHz). No error is thrown anywhere — setCategory, setActive, start(), and the tap callback all succeed. The PCM is literally all zeros (not low-level noise / room tone — exact 0.0). Two separate silent recordings decode to byte-identical AAC, confirming pure digital silence rather than corruption. So as far as our error handling, format checks, and tap-liveness are concerned, everything looks healthy — yet the microphone is delivering pure silence. One way we can reproduce it: recording while the iPhone is being driven via macOS iPhone Mirroring (the iPhone stays locked, the mic is effectively unavailable from the device, but our session still activates with a valid format and the tap fires zero-filled buffers for the whole recording — with no error at any point). What we've ruled out: microphone permission is granted; it's not truncation or short capture (full-length, full frame count); it's not our encoding step (the input buffers themselves are zero); it's not a quiet/obstructed mic (that would be low noise, not exact 0.0). We also found two existing threads describing what looks like the same symptom: https://developer.apple.com/forums/thread/834950 https://developer.apple.com/forums/thread/808072 Both of those are PushToTalk apps where the system activates the audio session, and an Apple engineer notes it may be related to a CallKit issue (r.157725305). For context on our side: we do use CallKit, but only CXCallObserver — purely to detect whether a phone call comes in while a recording is in progress, so we can pause and resume around it. We do not use CXProvider or PushToTalk, and we activate our own AVAudioSession ourselves with setActive(true). I'm trying to understand whether there are other scenarios or device states that could leave a running AVAudioEngine tap returning all-zero buffers like this, and whether this is the same underlying CallKit issue (r.157725305) from those threads . And since nothing throws an error, any guidance on how to detect this at runtime and recover from it would be really helpful.
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736
Activity
Jul ’26
AVAudioEngine input tap intermittently delivers all-zero buffers — valid format, no error thrown
We have a long-form audio recording app built on AVAudioEngine. We install a tap on inputNode, accumulate the PCM buffers, and encode them to AAC in ~60-second chunks. Setup is essentially: let session = AVAudioSession.sharedInstance() try session.setCategory(.playAndRecord, mode: .default, options: [.defaultToSpeaker, .allowBluetooth, .allowBluetoothA2DP]) try session.setActive(true) let engine = AVAudioEngine() let input = engine.inputNode let format = input.inputFormat(forBus: 0) // valid, e.g. 48 kHz, 1 ch input.installTap(onBus: 0, bufferSize: 1024, format: format) { buffer, _ in // In the failure case, buffer.floatChannelData is entirely 0.0 // (accumulate + encode to AAC) } engine.prepare() try engine.start() Intermittently — and so far only reported from the field, never reproduced in normal testing — a recording comes out completely silent. When we decode the resulting AAC and inspect the raw PCM, every sample is exactly 0.0. The signature is very specific: The engine is running and the tap keeps firing for the full duration (normal number of buffers / full-length chunks). inputFormat is valid (sampleRate ≠ 0, e.g. 48 kHz). No error is thrown anywhere — setCategory, setActive, start(), and the tap callback all succeed. The PCM is literally all zeros (not low-level noise / room tone — exact 0.0). Two separate silent recordings decode to byte-identical AAC, confirming pure digital silence rather than corruption. So as far as our error handling, format checks, and tap-liveness are concerned, everything looks healthy — yet the microphone is delivering pure silence. One way we can reproduce it: recording while the iPhone is being driven via macOS iPhone Mirroring (the iPhone stays locked, the mic is effectively unavailable from the device, but our session still activates with a valid format and the tap fires zero-filled buffers for the whole recording — with no error at any point). What we've ruled out: microphone permission is granted; it's not truncation or short capture (full-length, full frame count); it's not our encoding step (the input buffers themselves are zero); it's not a quiet/obstructed mic (that would be low noise, not exact 0.0). Questions: What other device states or scenarios can cause a running AVAudioEngine input tap to deliver all-zero buffers with a valid format and no error? (e.g. another process/system feature holding the mic, Continuity Camera/Mic, CallKit/PushToTalk session ownership, etc.) Since this surfaces with no error and a valid format, what is the recommended way to detect it at runtime? Is monitoring the input level / PCM energy the only signal, or is there a supported API to know the input isn't actually live? What's the recommended recovery once detected — is a full session deactivate/reactivate re-handshake sufficient, or is recreating the engine required?
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Jun ’26