Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.

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WebM audio playback
Is it possible to play WebM audio on iOS? Either with AVPlayer, AVAudioEngine, or some other API? Safari has supported this for a few releases now, and I'm wondering if I missed something about how to do this. By default these APIs don't seem to work (nor does ExtAudioFileOpen). Our usecase is making it possible for iOS users to play back audio recorded in our webapp (desktop versions of Chrome & Firefox only support webm as a destination format for MediaRecorder)
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446
Mar ’25
AVPlayer periodic time observer stops notifying when switching back from AirPlay to local playback
The app registers a periodic time observer to the AVPlayer when the playback starts and it works fine. When switching to AirPlay during playback, the periodic time observation continues working as expected. However, when switching back to local playback, the periodic time observer does not fire anymore until a seek is performed. The app removes the periodic time observer only when the playback stops. I can see that when switching back to local playback, the timeControlStatus successively changes to .waitingToPlayAtSpecifiedRate (reason: .evaluatingBufferingRate) then to .waitingToPlayAtSpecifiedRate (reason: .toMinimizeStalls) and finally to .playing But the time observation does not work anymore. Also, the issue is systematic with Live and VOD streams providing a program date (with HLS property #EXT-X-PROGRAM-DATE-TIME), with or without any DRM, and is never reproduced with other VOD streams.
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107
Apr ’25
"Remote call timed out" error when trying to play large collection of music items with MusicKit's ApplicationMusicPlayer
I am using MusicKit ApplicationMusicPlayer to play music in my app. Everything works fine as long as I'm not playing large playlists that contain hundreds of songs. When I to play collection of songs that is larger than around 300 I'm always getting the error message saying: "Prepare to play failed" UserInfo={NSDebugDescription=Prepare to play failed, NSUnderlyingError=0x121d42dc0 {Error Domain=MPMusicPlayerControllerErrorDomain Code=9 "Remote call timed out" UserInfo={NSDebugDescription=Remote call timed out}}})) It doesn't matter if songs are downloaded to the device or not. I am aware that there is another initializer for player's queue that accepts Playlist instances but in my app users can choose to sort playlist tracks in different order than the default and that makes using that initializer not feasible for me. I tried everything I could think of, I tried to fall back on MPMusicPlayerController and pass array of MPMusicPlayerPlayParameters to it but the result was the same. typealias QueueEntry = ApplicationMusicPlayer.Queue.Entry let player = ApplicationMusicPlayer.shared let entries: [QueueEntry] = tracks .compactMap { guard let song = $0 as? Song else { return nil } return QueueEntry(song) } Task(priority: .high) { [player] in do { player.queue = .init(entries, startingAt: nil) try await player.play() // prepareToPlay failed } catch { print(error) } }
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665
Mar ’25
Create live photo error
I want to create a Live Photo. The project includes a .jpg image and a .mov video (2 seconds). Two permissions in xcode have been added: Privacy - Photo Library Usage Description Privacy - Photo Library Additions Usage Description Simulate: iphone 16, ios 18.3 The codes in ContentView.swift : private func saveLivePhoto(imageURL: URL, videoURL: URL, completion: @escaping (Bool, Error?) -> Void) { PHPhotoLibrary.shared().performChanges { let creationRequest = PHAssetCreationRequest.forAsset() let options = PHAssetResourceCreationOptions() options.shouldMoveFile = false creationRequest.addResource(with: .photo, fileURL: imageURL, options: options) creationRequest.addResource(with: .pairedVideo, fileURL: videoURL, options: options) } completionHandler: { success, error in DispatchQueue.main.async { print(error) completion(success, error) } } } guard let imageURL = Bundle.main.url(forResource: "livephoto", withExtension: "jpeg"), let videoURL = Bundle.main.url(forResource: "livephoto", withExtension: "mov") else { showAlertMessage(title: "error", message: "cant find Live Photo ") return } print("imageURL: \(imageURL)") print("videoURL: \(videoURL)") saveLivePhoto(imageURL: imageURL, videoURL: videoURL) { success, error in if success { xxxxx } else { xxxxx } } Really need help, thanks
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193
Mar ’25
access transport in Logic Pro
hi, i need to read wether the transport is playing or stopped but my current method that works for vst does not work for au. is there a lpx resource available for developers anywhere? if (auto* playHead = processor->getPlayHead()) { juce::AudioPlayHead::CurrentPositionInfo posInfo; if (playHead->getCurrentPosition(posInfo)) { bool isCurrentlyPlaying = posInfo.isPlaying; if (isCurrentlyPlaying != wasTransportPlaying) { if (isCurrentlyPlaying) { wasTransportPlaying = isCurrentlyPlaying; startAllTimers(); } else { wasTransportPlaying = isCurrentlyPlaying; stopAllTimers(); } } } } thanks :)
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259
Mar ’25
AVPlayerItem. externalMetadata not available
According to the documentation (https://developer.apple.com/documentation/avfoundation/avplayeritem/externalmetadata), AVPlayerItem should have an externalMetadata property. However it does not appear to be visible to my app. When I try, I get: Value of type 'AVPlayerItem' has no member 'externalMetadata' Documentation states iOS 12.2+; I am building with a minimum deployment target of iOS 18. Code snippet: import Foundation import AVFoundation /// ... in function ... // create metadata as described in https://developer.apple.com/videos/play/wwdc2022/110338 var title = AVMutableMetadataItem() title.identifier = .commonIdentifierAlbumName title.value = "My Title" as NSString? title.extendedLanguageTag = "und" var playerItem = await AVPlayerItem(asset: composition) playerItem.externalMetadata = [ title ]
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73
Apr ’25
save audio file in iOS 18 instead of iOS 12
I'm able to get text to speech to audio file using the following code for iOS 12 iPhone 8 to create a car file: audioFile = try AVAudioFile( forWriting: saveToURL, settings: pcmBuffer.format.settings, commonFormat: .pcmFormatInt16, interleaved: false) where pcmBuffer.format.settings is: [AVAudioFileTypeKey: kAudioFileMP3Type, AVSampleRateKey: 48000, AVEncoderBitRateKey: 128000, AVNumberOfChannelsKey: 2, AVFormatIDKey: kAudioFormatLinearPCM] However, this code does not work when I run the app in iOS 18 on iPhone 13 Pro Max. The audio file is created, but it doesn't sound right. It has a lot of static and it seems the speech is very low pitch. Can anyone give me a hint or an answer?
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106
Mar ’25
"Baking together" two audio tracks into one for drag-and-drop
Hi all, with my app ScreenFloat, you can record your screen, along with system- and microphone audio. Those two audio feeds are recorded into separate audio tracks in order to individually remove or edit them later on. Now, these recordings you create with ScreenFloat can be drag-and-dropped to other apps instantly. So far, so good, but some apps, like Slack, or VLC, or even websites like YouTube, do not play back multiple audio tracks, just one. So what I'm trying to do is, on dragging the video recording file out of ScreenFloat, instantly baking together the two individual audio tracks into one, and offering that new file as the drag and drop file, so that all audio is played in the target app. But it's slow. I mean, it's actually quite fast, but for drag and drop, it's slow. My approach is this: "Bake together" the two audio tracks into a one-track m4a audio file using AVMutableAudioMix and AVAssetExportSession Take the video track, add the new audio file as an audio track to it, and render that out using AVAssetExportSession For a quick benchmark, a 3'40'' movie, step 1 takes ~1.7 seconds, and step two adds another ~1.5 seconds, so we're at ~3.2 seconds. That's an eternity for a drag and drop, where the user might cancel if there's no immediate feedback. I could also do it in one step, but then I couldn't use the AV*Passthrough preset, and that makes it take around 32 seconds then, because I assume it touches the video data (which is unnecessary in this case, so I think the two-step approach here is the fastest). So, my question is, is there a faster way? The best idea I can come up with right now is, when initially recording the screen with system- and microphone audio as separate tracks, to also record both of them into a third, muted, "hidden" track I could use later on, basically eliminating the need for step one and just ripping the two single audio tracks out of the movie and only have the video and the "hidden" track (then unmuted), but I'd still have a ~1.5 second delay there. Also, there's the processing and data overhead (basically doubling the movie's audio data). All this would be great for an export operation (where one expects it to take a little time), but for a drag-and-drop operation, it's not ideal. I've discarded the idea of doing a promise file drag, because many apps do not accept those, and I want to keep wide compatibility with all sorts of apps. I'd appreciate any ideas or pointers. Thank you kindly, Matthias
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656
Mar ’25
Some questions about musickit
We are developing an apple music app on phone, the developed web works fine on chrome, but when i load it on webivew on my phone, i can't play the first song, We doubt that the drm init, key exchange, session creation was on the music.play() function, while we trigger the play, the drm or session was not ok for play a real song, so it got an error so we may wanna know: what about the realative process of drm, key, session, etc in the play() function? are there some state detect function to show weather the drm is ok?
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111
Mar ’25
iPhone 16 Camera Control and AVCaptureSlider – Is there a way to detect which slider is active?
I am following the Apple sample code and trying to add a manual focus lens position slider: @available(iOS 18.0, *) private func addCameraControls() { if !self.session.controls.isEmpty { for control in self.session.controls { self.session.removeControl(control) } } self.cameraControlFocusSlider = nil //Focus Slider if self.videoDevice!.isLockingFocusWithCustomLensPositionSupported { self.cameraControlFocusSlider = AVCaptureSlider("Focus", symbolName: "dot.square", in: 0.0...1.0) self.cameraControlFocusSlider!.setActionQueue(self.sessionQueue) { focusValue in //Do manual focus } if self.session.canAddControl(self.cameraControlFocusSlider!) { self.session.addControl(self.cameraControlFocusSlider!) } } } So there are these AVCaptureSessionControlsDelegate methods: final func sessionControlsDidBecomeActive(_ session: AVCaptureSession) { print ("sessionControlsDidBecomeActive") } final func sessionControlsWillEnterFullscreenAppearance(_ session: AVCaptureSession) { print ("sessionControlsWillEnterFullscreenAppearance") } final func sessionControlsWillExitFullscreenAppearance(_ session: AVCaptureSession) { print ("sessionControlsWillExitFullscreenAppearance") } final func sessionControlsDidBecomeInactive(_ session: AVCaptureSession) { print ("sessionControlsDidBecomeInactive") } So when self.cameraControlFocusSlider is presented, I have to show the current value of the lense position. Lens position can change from auto focus and also from manual focus by the user using the app UI. Is there a way to see if self.cameraControlFocusSlider is active or being used? Please note that I will have more than one AVCaptureSlider in the final code.
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428
Mar ’25
AVAudioEngine Stop Method
Hi all! I have been experiencing some issues when using the AVAudioEngine to play audio and record input while doing a voice chat (through the PTT Interface). I noticed if I connect any players to the AudioGraph OR call start that the audio session becomes active (this is on iOS). I don't see anything in the docs or the header files in the AVFoundation, but is it possible that calling the stop method on an engine deactivates the audio session too? In a normal app this behavior seems logical, but when using PTT all activation and deactivation of the audio session must go through the framework and its delegate methods. The issue I am debugging is that when the engine with the input node tapped gets stopped, and there is a gap between the input and when the server replies with inbound audio to be played and something seems to be getting the hardware/audio session into a jammed state. Thanks for any feedback and/or confirmation on this behavior!
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637
Feb ’25
ApplicationMusicPlayer stops with error after skipping quickly over playlist entries
ApplicationMusicPlayer with queue created from playlist crashes with random occurrence shortly after skipping back or forth using controls embedded in the notification, with the error on console log: applicationController: xpc service connection interrupted. I've noticed that the issue occurs more frequently the shorter is time between skipping entries. Since ApplicationMusicPlayer is run on a remote process, the main app does not crash, but the music stops playing without any exception, and the playback control turns uninitiated. Here is how I'm initiating the queue: let entries = playlist .with(.entries).entries! .map { ApplicationMusicPlayer.Queue.Entry($0) } ApplicationMusicPlayer.shared.queue = .init( entries, startingAt: entries.last ) Please give me some tips on how to solve this. EDIT: The issue does not occur when navigating quickly through the station.
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510
Jan ’25
Help Needed: How to Make iOS Timer More Stable?
I’m currently developing an iOS metronome app using DispatchSourceTimer as the timer. The interval is set very small, around 50 milliseconds, and I’m using CFAbsoluteTimeGetCurrent to calculate the elapsed time to ensure the beat is played within a ±0.003-second margin. The problem is that once the app goes to the background, the timing becomes unstable—it slows down noticeably, then recovers after 1–2 seconds. When coming back to the foreground, it suddenly speeds up, and again, it takes 1–2 seconds to return to normal. It feels like the app is randomly “powering off” and then “overclocking.” It’s super frustrating. I’ve noticed that some metronome apps in the App Store have similar issues, but there’s one called “Professional Metronome” that’s rock solid with no such problems. What kind of magic are they using? Any experts out there who can help? Thanks in advance! P.S. I’ve already enabled background audio permissions. The professional metronome that has no issues: https://link.zhihu.com/?target=https%3A//apps.apple.com/cn/app/pro-metronome-%25E4%25B8%2593%25E4%25B8%259A%25E8%258A%2582%25E6%258B%258D%25E5%2599%25A8/id477960671
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555
Jan ’25
Enabling MIDINetworkSession in a catalyst app
Hi, I am trying to enable the default MIDINetworkSession in a Catalyst app on MacOS like this: MIDINetworkSession.default().isEnabled = true MIDINetworkSession.default().connectionPolicy = .anyone In the AppSandbox I have both incoming and outgoing network connections enabled. And I also added the NSLocalNetworkUsageDescription key to the info.plist. Bonjour services are also added to the info.plist: NSBonjourServices _apple-midi._udp. Nevertheless the session stays disabled. Running the same code works just fine on iOS. Is there any special setup I need to make on MacOS to enable the MIDINetworkSession? Thanks!
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451
Dec ’24
App recedes to background,audioEngine.start()
private var audioEngine = AVAudioEngine() private var inputNode: AVAudioInputNode! func startAnalyzing() { inputNode = audioEngine.inputNode let recordingFormat = inputNode.outputFormat(forBus: 0) let hardwareSampleRate = recordingSession.sampleRate inputNode.removeTap(onBus: 0) if recordingFormat.sampleRate != hardwareSampleRate { print("。") let newFormat = AVAudioFormat(commonFormat: recordingFormat.commonFormat, sampleRate: hardwareSampleRate, channels: recordingFormat.channelCount, interleaved: recordingFormat.isInterleaved) inputNode.installTap(onBus: 0, bufferSize: 1024, format: newFormat) { buffer, time in self.processAudioBuffer(buffer, time: time) } } else { inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { buffer, time in self.processAudioBuffer(buffer, time: time) } } do { audioEngine.prepare() try audioEngine.start() } catch { print(": \(error)") } } I back the app to the background and then call startAnalyzing(), which reports an error and the background recording permissions are configured。 error: [10429:570139] [aurioc] AURemoteIO.cpp:1668 AUIOClient_StartIO failed (561145187) [10429:570139] [avae] AVAEInternal.h:109 [AVAudioEngineGraph.mm:1545:Start: (err = PerformCommand(*ioNode, kAUStartIO, NULL, 0)): error 561145187 Audio engine couldn't start. Is background boot not allowed?
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515
Jan ’25
Why is the volume very low when using the real-time recording and playback feature with AEC?
I’ve been researching how to achieve a recording playback effect in iOS similar to the hands-free calling effect in the system’s phone app. How can this be implemented? I tried using the voice chat recording method, but found that the volume of the speaker output is too low. How should this issue be addressed? I couldn’t find a suitable API. Could you provide me with some documentation or sample code? Thank you.
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418
Feb ’25
Music Kit initialisation, Uncaught TypeError: Cannot read properties of undefined (reading 'node')
I'm trying to load Music Kit on the server with solid js. I can confirm that my implementation has been sufficient to return authentication tokens and for MusicKit.isAuthorized to return true. My issue is that if I reload the page, it only succeeds intermittently (perhaps 25% of the time?). My question is - what is wrong with my implementation? Removing the async keyword ensures it loads every time but playing and queuing music no longer works. I'm currently assuming this is an SSR issue but the docs haven't explicitly specified this isn't possible. I have the following boilerplate: export default createHandler( () => ( <StartServer document={({ assets, children, scripts }) => { return ( <html lang="en"> <head> <meta name="apple-music-developer-token" content={authResult.token} /> <meta name="apple-music-app-name" content="app name" /> <meta name="apple-music-app-build" content="1978.4.1" /> {assets} <script src="https://js-cdn.music.apple.com/musickit/v3/musickit.js" async /> </head> <body> <div id="app">{children}</div> {scripts} </body> </html> ) }} /> )) When I first load my app, I'll encounter: musickit.js:13 Uncaught TypeError: Cannot read properties of undefined (reading 'node') at musickit.js:13:10194 at musickit.js:13:140 at musickit.js:13:209 The intermittence signals an issue relating to the async keyword. An expansion on this issue can be found here.
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553
Dec ’24
Garageband displaying error 100001 when loading up some AU plugins
I recently got some plugins from Universal Audio, and have licensed them properly through both UA and iLok manager. Whenever I try to load up the plugins (specifically from UA) in GarageBand, it first says that "NSCreateObjectFileImageFromMemory-p47UEwps” because the developper can not be verified. After clicking either 'show in finder' or 'okay', it opens the plugin in a form without its GUI and showing that it is not licensed (even though it is). It also displays error code 100001. I have tried only some basic stuff to troubleshoot like restarting the DAW/my computer and reinstalling/relicensing the softwares. I don't know if the macOS version has anything to do with it but for some reason I just can't get it to work.
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385
Jan ’25