Calling MIDIFlushOutput on a network endpoint is not cancelling events scheduled with future timestamps -- they continue to send. e.g. func send(eventLists: [MIDIEventList]) { let outputPortRef = ... let networkDestination = ... for var eventList in eventLists { MIDISendEventList(outputPortRef, networkDestination.objectRef, &eventList) } } ... MIDIFlushOutput(networkDestination.objectRef) I'm seeing that MIDIFlushOutput does successfully cancel scheduled events on a non-network endpoint. How can I clear all scheduled outgoing events over a MIDI Network connection?

Whenever I have any bluetooth devices connected (radio, car, earphones) and want to record a voice message, the phone assumes I am recording from those devices, both in the messages app and any other app. Half of those devices I own don’t even have a microphone, then no message gets recorded. Can you implement a choice of microphone to be used when recording something? Some apps don’t even have the option to pick the audio output, which is annoying, but having to disable bluetooth to record something is definitely worse.

I have developed and operated a music player app, but when I installed the iOS 18 public beta version on my device and checked the app's operation, I found that the seek bar stops immediately after starting playback, and I cannot change the playback position on the seek bar. Checking the logs, the following error is output when the seek bar stops: ERROR AudioQueueCreateTimeline status=1953330284 This is a value I have never seen before, and this issue did not occur in iOS 17 or earlier. I would like to know if this issue can be resolved, and if not, how I should handle it.

When using the AVSpeechSynthesizer() , I get an error after a couple of seconds :"IPCAUClient.cpp:139 IPCAUClient: can't connect to server (-66748) <0x104309130>", and then it speaks the text. The second time I call speak, there is no delay and error and it speaks immediately. Where does this error and delay come from and how can I resolve it? Intialization code: self.audioSession = AVAudioSession.sharedInstance() // 2) handle audio session first, before trying to read the text do { try audioSession.setCategory(.playback, mode: .voicePrompt, options: .duckOthers) try audioSession.setActive(false) } catch let error { Logger.model.debug("❓\(error.localizedDescription)") } speechSynthesizer = AVSpeechSynthesizer() speechSynthesizer.usesApplicationAudioSession = true Speak code: let utterance = AVSpeechUtterance(string: text) utterance.preUtteranceDelay = 0.1 utterance.rate = 0.5 utterance.pitchMultiplier = 0.75 utterance.prefersAssistiveTechnologySettings = false self.speechSynthesizer.speak(utterance) The last statement gives this error message!

Hi! I'm developing a music player app that interchanges between ApplicationMusicPlayer and AVAudioEngine. I'm facing an issue when switching from playback via ApplicationMusicPlayer to AVAudioEngine while the app is in background. Based on testing, it seems like the issue has to do with being unable to set audio focus in background, causing error AVAudioSessionErrorCodeCannotInterruptOthers. I would like to check if ApplicationMusicPlayer has its own audio focus separated from the app's own audio focus. If it is, is there anything that I can do to ensure that ApplicationMusicPlayer returns focus to the app? (I notice that the issue does not occur if we are moving playback from AVAudioEngine to ApplicationMusicPlayer. Not sure why the opposite does not work)

I'm experiencing stuttering every time I record something with my iOS app on iOS 18 beta. The code ran fine on previous iOS versions. The stuttering occurs for the first 2 seconds. Here's an example: https://soundcloud.com/thomas-walther-219010679/ios-18-stuttering The way I set up AVAudioEngine and AVAudioSession was vetted quite thoroughly during sessions at WWDC '23. Here is how the engine and the tap is configured: let engine = AVAudioEngine() let recorderNode = AVAudioMixerNode() engine.attach(recorderNode) engine.connect(engine.mainMixerNode, to: engine.outputNode, format: engine.outputNode.inputFormat(forBus: 0)) engine.connect(recorderNode, to: engine.mainMixerNode, format: recordingOutputFormat) engine.connect(engine.inputNode, to: recorderNode, format: engine.inputNode.inputFormat(forBus: 0)) let bufferSize: AVAudioFrameCount = 4096 recorderNode.installTap(onBus: 0, bufferSize: bufferSize, format: nil) { [weak self] buffer, time in guard let self = self else { return } do { // Write recording to disk try audioFile.write(buffer) } catch { // ... } } I tried setting a different buffer size, but with no luck. I also can't see any hangs in Instruments. Do you have any pointers on how to debug this?

Media Player album artwork images do not release memory after loading so memory accumulates, eventually impacting performance and causing crashes. Steps To Reproduce: Download example project and run on device Grant access to library of 100+ albums Scroll through albums on any tab screen Observe steady memory increase in Xcode debug navigator and crash as you scroll Observe same memory accumulation on other screens that use different methods to get album artwork images Observations: Various methods of obtaining album artwork insufficiently release memory and impact app performance. 1 - Artwork Image releases memory sometimes if the images are small and you scroll slow, but app will still accumulate memory, drop frames when scrolling, and eventually crash. 2 - Value For Property behaves similar to Artwork Image even when using the implicit size of the artwork bounds. 3 - Image From Disk problem seems related to perform() method since you can remove UIImage and memory still accumulates All 3 methods result in higher retain counts than expected for artwork objects that could be preventing memory from releasing

hi, i am currently developing an app that has core functionalities reliant on detecting user laughter in the background. in our early stages we noticed apple's built-in sound recognition functionality. at the core, i am guessing that sound recognition requires permission from the user to access the microphone 24/7. currently, using the conventional avenue of background audio recording, a yellow indicator will be present on the top of the iphone screen indicating recording. this is not the case for sound recognition; instead. if all sound processing/recognition is kept on-device, is there any way to avoid the yellow dot and achieve sound laughter in a way that is similar to how apple's sound recognition does it? from the settings interface for sound recognition accessible to the user in the settings app, the only detectable "people" sounds are baby crying, coughing, and shouting. is it also possible to add laughter to this list somehow? thank you in advance.

I need to find a way to allow recording from the mic while outputting two different sound streams to two different devices (speaker and headphones). I've done a fair bit of reading around using AVAudioSession.Category.multiroute but haven't found any modern examples. @theanalogkid posted a nice example using obj-C nine years ago, but others have noted that the code isn't readily translatable to Swift. To make matters worse, this is one of the very few examples on how to properly use multirouting. The official documentation is lacking, to say the least, and the WWDC 2012 session is, well, old enough to attend middle school and be a Taylor Swift fan, but definitely not in Swift. The few relevant forum posts here are spread over this middle schooler's life span and likely outdated, with most having no responses other than the poster's own plightful echo. They don't paint a pretty picture of .multiroute's health, with a recent poster noting that volume buttons don't work in this mode, contacting DTS and finding that there's no fix; another finding that it just doesn't work for certain devices, etc. Audio is giving me enough of a headache so I'd like to avoid slogging through this if possible. .multiroute feels like the developer mode of AVAudioSession, but without documentation. tl;dr - Without using .multiroute, is there a way to allow an app to output two different devices while simultaneously recording audio? If .multiroute is the only way to achieve this, can someone give me a quick rundown of how this category works?

Audio getting disabled, Not able to control audio, When opening music player audio works but not on instagram or any other apps. Audio button on notification bar is greyed out as getting disabled.

I am developing a visionOS app that captions speech in real environments. Currently, I am using Apple's built-in speech recognizer. However, when I was testing the app with a Vision Pro, the device seemed to only pick up the user's voice (in other words, the voices of the wearer of the Vision Pro device). For example, when the speech recognition task is running, and another person in front of me is talking, the system does not pick up the speech well. I tried to set the AVAudioSession to be equally sensitive to all directions: private func configureAudioSession() { do { try audioSession.setCategory(.record, mode: .measurement) try audioSession.setActive(true) if #available(visionOS 1.0, *) { let availableDataSources = audioSession.availableInputs?.first?.dataSources if let omniDirectionalSource = availableDataSources?.first(where: {$0.preferredPolarPattern == .omnidirectional}) { try audioSession.setInputDataSource(omniDirectionalSource) } } } catch { print("Failed to set up audio session: \(error)") } } And here is how I set up the speech recognition and configure the microphone inputs: private func startSpeechRecognition(completion: @escaping (String) -> Void) { do { // Cancel the previous task if it's running. if let recognitionTask = recognitionTask { recognitionTask.cancel() self.recognitionTask = nil } // The AudioSession is already active, creating input node. let inputNode = audioEngine.inputNode try inputNode.setVoiceProcessingEnabled(false) // Create and configure the speech recognition request recognitionRequest = SFSpeechAudioBufferRecognitionRequest() guard let recognitionRequest = recognitionRequest else { fatalError("Unable to create a recognition request") } recognitionRequest.shouldReportPartialResults = true // Keep speech recognition data on device if #available(iOS 13, *) { recognitionRequest.requiresOnDeviceRecognition = true } // Create a recognition task for speech recognition session. // Keep a reference to the task so that it can be canceled. recognitionTask = speechRecognizer?.recognitionTask(with: recognitionRequest) { result, error in // var isFinal = false if let result = result { // Update the recognizedText completion(result.bestTranscription.formattedString) } else if let error = error { completion("Recognition error: \(error.localizedDescription)") } if error != nil || result?.isFinal == true { // Stop recognizing speech if there is a problem self.audioEngine.stop() inputNode.removeTap(onBus: 0) self.recognitionRequest = nil self.recognitionTask = nil } } // Configure the microphone input let recordingFormat = inputNode.outputFormat(forBus: 0) inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, when) in self.recognitionRequest?.append(buffer) } audioEngine.prepare() try audioEngine.start() } catch { completion("Audio engine could not start: \(error.localizedDescription)") } }

Description: I am developing a recording-only application that supports background recording using AVAudioEngine. The app segments the recording into 60-second files for further processing. For example, a 10-minute recording results in ten 60-second files. Problem: The application functions as expected in the background. However, after the app receives an interruption (such as a phone call) and the interruption ends, I can successfully restart the recording. The problem arises when the app then transitions to the background; it fails to restart the recording. Specifically, after ending the call and transitioning the app to the background, the app encounters an error and is unable to restart AVAudioSession and AVAudioEngine. The only resolution is to close and restart the app, which is not ideal for user experience. Steps to Reproduce: 1. Start recording using AVAudioEngine. 2. The app records and saves 60-second segments. 3. Receive an interruption (e.g., an incoming phone call). 4. End the call. 5. Transition the app to the background. 6. Transition the app to the foreground and the session will be activated again. 7. Attempt to restart the recording. Expected Behavior: The app should resume recording seamlessly after the interruption and background transition. Actual Behavior: The app fails to restart AVAudioSession and AVAudioEngine, resulting in a continuous error. The recording cannot be resumed without closing and reopening the app. How I’m Starting the Recording: Configuration: internal func setAudioSessionCategory() { do { try audioSession.setCategory( .playAndRecord, mode: .default, options: [.defaultToSpeaker, .mixWithOthers, .allowBluetooth] ) } catch { debugPrint(error) } } internal func setAudioSessionActivation() { if UIApplication.shared.applicationState == .active { do { try audioSession.setPrefersNoInterruptionsFromSystemAlerts(true) try audioSession.setActive(true, options: .notifyOthersOnDeactivation) if audioSession.isInputGainSettable { try audioSession.setInputGain(1.0) } try audioSession.setPreferredIOBufferDuration(0.01) try setBuiltInPreferredInput() } catch { debugPrint(error) } } } Starting AVAudioEngine: internal func setupEngine() { if callObserver.onCall() { return } inputNode = audioEngine.inputNode audioEngine.attach(audioMixer) audioEngine.connect(inputNode, to: audioMixer, format: AVAudioFormat.validInputAudioFormat(inputNode)) } internal func beginRecordingEngine() { audioMixer.removeTap(onBus: 0) audioMixer.installTap(onBus: 0, bufferSize: 1024, format: AVAudioFormat.validInputAudioFormat(inputNode)) { [weak self] buffer, _ in guard let self = self, let file = self.audioFile else { return } write(file, buffer: buffer) } audioEngine.prepare() do { try audioEngine.start() recordingTimer = Timer.scheduledTimer(withTimeInterval: recordingInterval, repeats: true) { [weak self] _ in self?.handleRecordingInterval() } } catch { debugPrint(error) } } On the try audioEngine.start() call, I receive error code 561145187 in the catch block. Logs/Error Messages: • Error code: 561145187 Request: I would appreciate any guidance or solutions to ensure the app can resume recording after interruptions and background transitions without requiring a restart. Thank you for your assistance.

When listening to music in carplay, the sound quality is very bad and I can't turn down the volume of the music. it acts like a voice assistant instead of music. when turning the volume down and up, it's like adjusting the volume of the voice assistant when it should turn up the volume of the music. So instead of music, it acts like the voice assistant is activated. This was previously reported in iOS 18 Beta 2. I have a 2024 Honda Ridgeline Black Edition.

If a queue (ApplicationMusicPlayer.Queue) is set with both library and non-library (catalog) items, the queue will play only one kind of item (library or non-library) or will just stop playing when the next item is of a different kind. Using both Xcode 16 beta 4 and Xcode 15.4. The issue was present in iOS 17 and is not resolved as of iOS 18 beta 4. FB14491999

I would really like to know if it is possible to get a state for the ringer on iOS. In my application I want to repeat the logic of audio rules from Instagram during watching a video. The video plays with sound. When the ringer switches to mute status the video's audio should be muted too. When you press the volume up or down button the audio should be unmuted. I found how to catch volume up/down buttons with AVAudioSession.sharedInstance().observe(\.outputVolume) but I couldn't find anything that could help me with the ringer state. AVAudioSession.Category can't achieve this effect. Also there is a possibility to check ringer state with Darwin notify lib like var token = NOTIFY_TOKEN_INVALID notify_register_dispatch( "com.apple.springboard.ringerstate", &token, .main ) { token in var state: UInt64 = 0 notify_get_state(token, &state) print("Changed to", state == 1 ? "ON" : "OFF") } but I'm not sure that this won't lead to the application being rejected. I don't know is it a private API usage or not. I will be glad to any advice and suggestions. Thanks

Hello ! I am working on an app connected to an external streamer . I would like to display current playing song on the Lock Screen. I tried to update the information in MPNowPlayingInfoCenter but I need to play a sound on my iPhone for the control to be displayed . Is there a way to do it without playing a sound? If not, playing a silent sound would be the only solution ? validated by Apple ? :-/ Thank you Frederic

I'm building an app that will allow users to record voice notes. The functionality of all that is working great; I'm trying to now implement changes to the AudioSession to manage possible audio streams from other apps. I want it so that if there is audio playing from a different app, and the user opens my app; the audio keep playing. When we start recording, any third party app audio should stop, and can then can resume again when we stop recording. This is my main audio setup code: private var audioEngine: AVAudioEngine! private var inputNode: AVAudioInputNode! func setupAudioEngine() { audioEngine = AVAudioEngine() inputNode = audioEngine.inputNode audioPlayerNode = AVAudioPlayerNode() audioEngine.attach(audioPlayerNode) let format = AVAudioFormat(standardFormatWithSampleRate: AUDIO_SESSION_SAMPLE_RATE, channels: 1) audioEngine.connect(audioPlayerNode, to: audioEngine.mainMixerNode, format: format) } private func setupAudioSession() { let audioSession = AVAudioSession.sharedInstance() do { try audioSession.setCategory(.playAndRecord, mode: .default, options: [.defaultToSpeaker, .allowBluetooth]) try audioSession.setPreferredSampleRate(AUDIO_SESSION_SAMPLE_RATE) try audioSession.setPreferredIOBufferDuration(0.005) // 5ms buffer for lower latency try audioSession.setActive(true) // Add observers setupInterruptionObserver() } catch { audioErrorMessage = "Failed to set up audio session: \(error)" } } This is all called upon app startup so we're ready to record whenever the user presses the record button. However, currently when this happens, any outside audio stops playing. I isolated the issue to this line: inputNode = audioEngine.inputNode When that's commented out, the audio will play -- but I obviously need this for recording functionality. Is this a bug? Expected behavior?

I tried to play music on my iPhone and it keeps skipping over all of the songs and not playing any music.

I’m having issues with volume after installing ios 18 beta 4. The volume toggle in control centre is turned up to full volume and is disabled. It only gets enabled after playing music. As soon as I pause music it gets disabled and my iPhone turns mute. Also having issue when playing music on AirPods; as soon as I turn my screen on, the music pauses. It happens every time o do this action.

Hi there community, First and foremost, a big thank you to everyone who takes the time to read this. TL;DR: How, if even possible, can I record multiple audio streams simultaneously on an iOS application (iPad/iPhone)? I'm working on a recorder for the iPad to gather data for a machine learning project focused on speech recognition. Our goal is to capture extensive speech data, which requires recording from multiple microphones. Specifically, I need to record from all mics connected to our Scarlett 4i4 audio interface and, most importantly, also record from the built-in mic on the iPad or iPhone at the same time. As a newcomer to Swift development, I initially explored AVAudioRecorder. However, I quickly realized that it only supports one active audio node at a time, making multi-channel recording impossible. (perhaps you can proof me wrong, would make my day) Next, I transitioned to using AVAudioEngine, but encountered the same limitation: I couldn't manage to get input nodes for both the built-in mic and the Scarlett interface channels simultaneously. The application started behaving oddly, often resulting in identical audio data being recorded across all files. Determined to find a solution, I delved deeper into the Core Audio framework, specifically using Audio Toolbox. My approach involved creating and configuring multiple Audio Units, each corresponding to a different audio input device. Here's a brief overview of my current implementation: Listing Available Input Devices: I used AVAudioSession to enumerate all available input devices. Creating Audio Units: For each device, I created an Audio Unit and attempted to configure it for recording. Setting Up Callbacks: I set up input and output callbacks to handle the audio processing. Despite my efforts over the last few days, I haven't had much success. The callbacks for the Audio Units don't seem to be invoked correctly, and I'm struggling to achieve simultaneous multi-channel recording. Below is a snippet of my latest attempt: let audioUnitCallback: AURenderCallback = { ( inRefCon: UnsafeMutableRawPointer, ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>, inTimeStamp: UnsafePointer<AudioTimeStamp>, inBusNumber: UInt32, inNumberFrames: UInt32, ioData: UnsafeMutablePointer<AudioBufferList>? ) -> OSStatus in guard let ioData = ioData else { return noErr } print("Input callback invoked") let audioUnit = inRefCon.assumingMemoryBound(to: AudioUnit.self).pointee var bufferList = AudioBufferList( mNumberBuffers: 1, mBuffers: AudioBuffer( mNumberChannels: 1, mDataByteSize: 0, mData: nil ) ) let status = AudioUnitRender(audioUnit, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, &bufferList) if status != noErr { print("AudioUnitRender failed: \(status)") return status } // Copy rendered data to output buffer let buffer = UnsafeMutableAudioBufferListPointer(ioData)[0] buffer.mData?.copyMemory(from: bufferList.mBuffers.mData!, byteCount: Int(bufferList.mBuffers.mDataByteSize)) buffer.mDataByteSize = bufferList.mBuffers.mDataByteSize print("Rendered audio data") return noErr } let outputCallback: AURenderCallback = { ( inRefCon: UnsafeMutableRawPointer, ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>, inTimeStamp: UnsafePointer<AudioTimeStamp>, inBusNumber: UInt32, inNumberFrames: UInt32, ioData: UnsafeMutablePointer<AudioBufferList>? ) -> OSStatus in guard let ioData = ioData else { return noErr } print("Output callback invoked") // Process the output data if needed return noErr } In essence, I'm stuck and in need of guidance. Has anyone here successfully implemented multi-channel recording on iOS, especially involving both built-in microphones and external audio interfaces? Any shared experiences, insights, or suggestions on how to proceed would be immensely appreciated. Thank you once again for your time and assistance!