I have a simple AVAudioEngine graph as follows:
AVAudioPlayerNode -> AVAudioUnitEQ -> AVAudioUnitTimePitch -> AVAudioUnitReverb -> Main mixer node of AVAudioEngine.
I noticed that whenever I have AVAudioUnitTimePitch or AVAudioUnitVarispeed in the graph, I noticed a very distinct crackling/popping sound in my Airpods Pro 2 when starting up the engine and playing the AVAudioPlayerNode and unable to find the reason why this is happening. When I remove the node, the crackling completely goes away. How do I fix this problem since i need the user to be able to control the pitch and rate of the audio during playback.
import AVKit
@Observable @MainActor
class AudioEngineManager {
nonisolated private let engine = AVAudioEngine()
private let playerNode = AVAudioPlayerNode()
private let reverb = AVAudioUnitReverb()
private let pitch = AVAudioUnitTimePitch()
private let eq = AVAudioUnitEQ(numberOfBands: 10)
private var audioFile: AVAudioFile?
private var fadePlayPauseTask: Task<Void, Error>?
private var playPauseCurrentFadeTime: Double = 0
init() {
setupAudioEngine()
}
private func setupAudioEngine() {
guard let url = Bundle.main.url(forResource: "Song name goes here", withExtension: "mp3") else {
print("Audio file not found")
return
}
do {
audioFile = try AVAudioFile(forReading: url)
} catch {
print("Failed to load audio file: \(error)")
return
}
reverb.loadFactoryPreset(.mediumHall)
reverb.wetDryMix = 50
pitch.pitch = 0 // Increase pitch by 500 cents (5 semitones)
engine.attach(playerNode)
engine.attach(pitch)
engine.attach(reverb)
engine.attach(eq)
// Connect: player -> pitch -> reverb -> output
engine.connect(playerNode, to: eq, format: audioFile?.processingFormat)
engine.connect(eq, to: pitch, format: audioFile?.processingFormat)
engine.connect(pitch, to: reverb, format: audioFile?.processingFormat)
engine.connect(reverb, to: engine.mainMixerNode, format: audioFile?.processingFormat)
}
func prepare() {
guard let audioFile else { return }
playerNode.scheduleFile(audioFile, at: nil)
}
func play() {
DispatchQueue.global().async { [weak self] in
guard let self else { return }
engine.prepare()
try? engine.start()
DispatchQueue.main.async { [weak self] in
guard let self else { return }
playerNode.play()
fadePlayPauseTask?.cancel()
playPauseCurrentFadeTime = 0
fadePlayPauseTask = Task { [weak self] in
guard let self else { return }
while true {
let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: true)
// Ramp up volume until 1 is reached
if volume >= 1 { break }
engine.mainMixerNode.outputVolume = volume
try await Task.sleep(for: .milliseconds(10))
playPauseCurrentFadeTime += 0.01
}
engine.mainMixerNode.outputVolume = 1
}
}
}
}
func pause() {
fadePlayPauseTask?.cancel()
playPauseCurrentFadeTime = 0
fadePlayPauseTask = Task { [weak self] in
guard let self else { return }
while true {
let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: false)
// Ramp down volume until 0 is reached
if volume <= 0 { break }
engine.mainMixerNode.outputVolume = volume
try await Task.sleep(for: .milliseconds(10))
playPauseCurrentFadeTime += 0.01
}
engine.mainMixerNode.outputVolume = 0
playerNode.pause()
// Shut down engine once ramp down completes
DispatchQueue.global().async { [weak self] in
guard let self else { return }
engine.pause()
}
}
}
private func updateVolume(for x: Double, rising: Bool) -> Float {
if rising {
// Fade in
return Float(pow(x, 2) * (3.0 - 2.0 * (x)))
} else {
// Fade out
return Float(1 - (pow(x, 2) * (3.0 - 2.0 * (x))))
}
}
func setPitch(_ value: Float) {
pitch.pitch = value
}
func setReverbMix(_ value: Float) {
reverb.wetDryMix = value
}
}
struct ContentView: View {
@State private var audioManager = AudioEngineManager()
@State private var pitch: Float = 0
@State private var reverb: Float = 0
var body: some View {
VStack(spacing: 20) {
Text("🎵 Audio Player with Reverb & Pitch")
.font(.title2)
HStack {
Button("Prepare") {
audioManager.prepare()
}
Button("Play") {
audioManager.play()
}
.padding()
.background(Color.green)
.foregroundColor(.white)
.cornerRadius(10)
Button("Pause") {
audioManager.pause()
}
.padding()
.background(Color.red)
.foregroundColor(.white)
.cornerRadius(10)
}
VStack {
Text("Pitch: \(Int(pitch)) cents")
Slider(value: $pitch, in: -2400...2400, step: 100) { _ in
audioManager.setPitch(pitch)
}
}
VStack {
Text("Reverb Mix: \(Int(reverb))%")
Slider(value: $reverb, in: 0...100, step: 1) { _ in
audioManager.setReverbMix(reverb)
}
}
}
.padding()
}
}
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Hi,
I am trying to remove the audio controls for my app on the lock screen. Since I use WKWebView, there are 3 audio tags in my html and I play and pause em via JS. However, if I do not play any sound since app launch, there are no audio controls on the lock screen. But if I play one of those 3 files (they are even less then 3 Sec sound effects e.g. for buttons) the audio controls appears on lock screen.
Note even when the sounds on pause() or not playing they were listed on the lock screen.
What I have tried so far without success
MPNowPlayingInfoCenter.default().nowPlayingInfo = [:]
and
``try audioSession.setCategory(.playback, mode: .default, options: [])
try audioSession.setActive(false, options: .notifyOthersOnDeactivation)``
and
UIApplication.shared.endReceivingRemoteControlEvents()
Another problem is that the app scales with iOS system settings "display zoom". Is there a way to deny it?
It is latest Xcode verion 16.3 and iOS 18.
I have no background mode in my Capabilities.
Nothing worked so far. Has anyone an idea?
Greetings
I work on an iOS app that records video and audio. We've been getting reports for a while from users who are experiencing their video recordings being cut off. After investigating, I found that many users are receiving the AVAudioSessionMediaServicesWereResetNotification (.mediaServicesWereResetNotification) notification while recording. It's associated with the AVFoundationErrorDomain[-11819] error, which seems to indicate that the system audio daemon crashed. We have a handler registered to end the recording, show the user a prompt, and restart our AV sessions. However, from our logs this looks to be happening to hundreds of users every day and it's not an ideal user experience, so I would like to figure out why this is happening and if it's due to something that we're doing wrong.
The debug menu option to trigger the audio session reset is not of much use, because it can't be triggered unless you leave the app and go to system settings. So our app can't be recording video when the debug reset is triggered. So far I haven't found a way to reproduced the issue locally, but I can see that it's happening to users from logs.
I've found some posts online from developers experiencing similar issues, but none of them seem to directly address our issue. The system error doesn't include a userInfo dictionary, and as far as I can tell it's a system daemon crash so any logs would need to be captured from the OS.
Is there any way that I could get more information about what may be causing this error that I may have missed?
Topic:
Media Technologies
SubTopic:
Audio
I’m working with the Push-to-Talk (PTT) framework and observing a consistent delay when starting audio capture.
Scenario:
A PTT call is already active
The AVAudioSession is fully configured
I request beginTransmission on the PTT channel
I start my Audio Unit for recording (AudioOutputUnitStart)
Observed behavior:
AudioOutputUnitStart takes ~500 ms
This happens whether I start the Audio Unit:
after didBeginTransmission, or
after AVAudioSession didActivate
Comparison:
Using the same Audio Unit, same format, and same configuration
Without the PTT framework, AudioOutputUnitStart takes ~200 ms
Additional notes:
I am not modifying or reconfiguring AVAudioSession when requesting beginTransmission
The audio session is already set up when the PTT call starts
There are no interruptions or route changes at the time of starting the Audio Unit
Impact:
This extra latency is significant for Push-to-Talk use cases where fast transmit
start is critical.
I might have misunderstood the docs, but is Call Translation going to be available for VOIP applications? Eg in an already connected VOIP call, would it be possible for Call Translations to be enabled on an iOS 26 and Apple Intelligence supported device?
I have personally tried it and it doesn’t look like it supported VOIP but would love to confirm this.
reference: https://developer.apple.com/documentation/callkit/cxsettranslatingcallaction/
Topic:
Media Technologies
SubTopic:
Audio
I have a PCM audio buffer (AVAudioPCMFormatInt16). When I try to play it using AVPlayerNode / AVAudioEngine an exception is thrown:
"[[busArray objectAtIndexedSubscript:(NSUInteger)element] setFormat:format error:&nsErr]: returned false, error Error Domain=NSOSStatusErrorDomain Code=-10868
(related thread https://forums.developer.apple.com/forums/thread/700497?answerId=780530022#780530022)
If I convert the buffer to AVAudioPCMFormatFloat32 playback works.
My questions are:
Does AVAudioEngine / AVPlayerNode require AVAudioPCMBuffer to be in the Float32 format? Is there a way I can configure it to accept another format instead for my application?
If 1 is YES is this documented anywhere?
If 1 is YES is this required format subject to change at any point?
Thanks!
I was looking to watch the "AVAudioEngine in Practice" session video from WWDC 2014 but I can't find it anywhere (https://forums.developer.apple.com/forums/thread/747008).
I'm using the new SpeechAnalyzer framework to detect certain commands and want to improve accuracy by giving context. Seems like AnalysisContext is the solution for this, but couldn't find any usage example. So I want to make sure that I'm doing it right or not.
let context = AnalysisContext()
context.contextualStrings = [
AnalysisContext.ContextualStringsTag("commands"): [
"set speed level",
"set jump level",
"increase speed",
"decrease speed",
...
],
AnalysisContext.ContextualStringsTag("vocabulary"): [
"speed", "jump", ...
]
]
try await analyzer.setContext(context)
With this implementation, it still gives outputs like "Set some speed level", "It's speed level", etc.
Also, is it possible to make it expect number after those commands, in order to eliminate results like "set some speed level to" (instead of two).
The AVB AVnu MILAN Convention has a groweing Population. Many big companies (Cisco, Meyer Sound, d&b Audio, l‘acoustics, Presonus, digico etc.) implements the AVB AVnu Milan Standards. Is there a plan on the Apple side to also implement AVnu Milan on top of the AVB Protocol?
The advantage for Apple Sound would be a great Integration in the professionell Audio market and a more stable intergration on top of the AVB protocol. The atdecc work, but Not that stable.
Topic:
Media Technologies
SubTopic:
Audio
I've got a problem with my app where I'm testing it on my own phone.
I'm using audio kit to generate tones as part of the app. Everything seems to work fine. Sounds start, Stop, etc. They play when the app is closed and when the phone is locked, so background is working.
However, I'm seeing an issue where, even when STOP is pressed and the application exited, if I get a notification such as a text message, the base tone for the app starts to play.
If I then open the app, check the Start/Stop button - it says start so that. hasnt' been activated. If I click Start, then a 2nd tone starts. This one stops with the Stop button. However the original tone that was set off by an incoming message carries on playing.
Until I go to the Open Apps View on the phone and slide the application upwards.
For the life of me, I can't figure out whats happening here.
I'm using AVFoundation to make a multi-track editor app, which can insert multiple track and clip, including scale some clip to change the speed of the clip, (also I'm not sure whether AVFoundation the best choice for me) but after making the scale with scaleTimeRange API, there is some short noise sound in play back. Also, sometimes it's fine when play AVMutableCompostion using AVPlayer with AVPlayerItem, but after exporting with AVAssetReader, will catch some short noise sounds in result file.... Not sure why.
Here is the example project, which can build and run directly. https://github.com/luckysmg/daily_images/raw/refs/heads/main/TestDemo.zip
I am developing a VOD playback app, but when I stream video to an external monitor connected via HDMI with Lightning on iOS 18 or later, the screen goes dark and I cannot confirm playback.
The app I am developing does not detect the HDMI and display the Player separately, but simply mirrors the video.
We have confirmed that the same phenomenon occurs with other services, but we were able to confirm playback with some services such as Apple TV.
Please let us know if there are any other necessary settings such as video certificates required for video playback.
We would also like to know if the problem occurs with iOS 18 or later.
Topic:
Media Technologies
SubTopic:
Audio
Since MacOS 26 Apple Music has inconsitent drops to the Quality of some Tracks indiscrimantly. I don't know if others Expereinced it. It doesn't happen on the Speakers or connected via Bluetooth, but the AUX I/O has it quite often. It is more noticable on Headphones with 48kHz and higher Frequency Bandwidth.
Here is the FB18062589
I have sent in a feedback report (FB18222398) but I have no idea if anyone has looked at it. I know from past experiences that Apple devs do look at these forums.
This applies to each of the betas, 1, 2 and 3. I have created a new Personal Voice with each beta. I create a personal voice in English. When it's done processing, I tap Preview and it says in English what is expected. But after some time, an hour or a day, the language of the voice file changes languages and no longer works properly. If I press Preview it is no longer intelligible. I have a text to speech app and initially the created voice works but then when the language of the file changes, it no longer works. I have run an app on my iphone through Xcode that prints to the console the voices installed on the device with the language. Currently this is the voice file:
Voice Identifier: com.apple.speech.personalvoice.AAA9C6F2-9125-475F-BA2F-22C63274991D
Language: es-MX
and on a second device the same personal voice is in a different language:
Voice Identifier: com.apple.speech.personalvoice.AAA9C6F2-9125-475F-BA2F-22C63274991D
Language: zh-CN
Although, a previous personal voice file that listed as Spanish-Mexican played in English with a Spanish accent or when playing Spanish text, it sounded almost perfect. This current personal voice doesn't do that, and is unintelligible. Previous attempts have converted to Chinese.
I hope someone can look into this.
Hi,
Not sure if this is the right forum to ask this question in, but could you please advise if I can use Apple Digital Masters logo (badge) in my iOS app that is playing music from Apple Music service?
Topic:
Media Technologies
SubTopic:
Audio
It sounds simple but searching for the name "Favorite Songs" is a non-starter because it's called different names in different countries, even if I specify "&l=en_us" on the query.
So is there another property, relationship or combination thereof which I can use to tell me when I've found the right playlist?
Properties I've looked at so far:
canEdit: will always be false so narrows things down a little
inFavorites: not helpful as it depends on whether the user has favourite the favourites playlist, so not relevant
hasCatalog: seems always true so again may narrow things down a bit
isPublic: doesn't help
Adding the catalog relationship doesn't seem to show anything immediately useful either.
Can anyone help?
Ideally I'd like to see this as a "kind" or "type" as it has different properties to other playlists, but frankly I'll take anything at this point.
When multiple identical songs are added to a playlist, Playlist.Entry.id uses a suffix-based identifier (e.g. songID_0, songID_1, etc.). Removing one entry causes others to shift, changing their .id values. This leads to diffing errors and collection view crashes in SwiftUI or UIKit when entries are updated.
Steps to Reproduce:
Add the same song to a playlist multiple times.
Observe .id.rawValue of entries (e.g. i.SONGID_0, i.SONGID_1).
Remove one entry.
Fetch playlist again — note the other IDs have shifted.
FB18879062
Hello,
I have an existing AUv3 instrument plugin. In the plug in, users can access files (audio files, song projects) via a UIDocumentPickerViewController
In Logic Pro, (and some other hosts, but not all), the document picker is unable to receive touches, while a keyboard case is attached to the iPad.
Removing the case (this is an Apple brand iPad case) allows the interactions to resume and allows me to pick files in the usual way.
One of my users reports this non-responsive behavior occurs even after disconnecting their keyboard.
I have fiddled with entitlements all day, and have determined that is not the issue, since the keyboard disconnection appears to fix it every time for me.
Here is my, very boilerplate, presentation code :
guard let type = UTType("com.my.type") else {
return
}
let fileBrowser = UIDocumentPickerViewController(forOpeningContentTypes: [type])
fileBrowser.overrideUserInterfaceStyle = .dark
fileBrowser.delegate = self
fileBrowser.directoryURL = myFileFolderURL()
self.present(fileBrowser, animated: true) {
I'm developing a TTS Audio Unit Extension that needs to write trace/log files to a shared App Group container. While the main app can successfully create and write files to the container, the extension gets sandbox denied errors despite having proper App Group entitlements configured.
Setup:
Main App (Flutter) and TTS Audio Unit Extension share the same App Group
App Group is properly configured in developer portal and entitlements
Main app successfully creates and uses files in the container
Container structure shows existing directories (config/, dictionary/) with populated files
Both targets have App Group capability enabled and entitlements set
Current behavior:
Extension can access/read the App Group container
Extension can see existing directories and files
All write attempts are blocked with "sandbox deny(1) file-write-create" errors
Code example:
const char* createSharedGroupPathWithComponent(const char* groupId, const char* component) {
NSString* groupIdStr = [NSString stringWithUTF8String:groupId];
NSString* componentStr = [NSString stringWithUTF8String:component];
NSURL* url = [[NSFileManager defaultManager]
containerURLForSecurityApplicationGroupIdentifier:groupIdStr];
NSURL* fullPath = [url URLByAppendingPathComponent:componentStr];
NSError *error = nil;
if (![[NSFileManager defaultManager] createDirectoryAtPath:fullPath.path
withIntermediateDirectories:YES
attributes:nil
error:&error]) {
NSLog(@"Unable to create directory %@", error.localizedDescription);
}
return [[fullPath path] UTF8String];
}
Error output:
Sandbox: simaromur-extension(996) deny(1) file-write-create /private/var/mobile/Containers/Shared/AppGroup/36CAFE9C-BD82-43DD-A962-2B4424E60043/trace
Key questions:
Are there additional entitlements required for TTS Audio Unit Extensions to write to App Group containers?
Is this a known limitation of TTS Audio Unit Extensions?
What is the recommended way to handle logging/tracing in TTS Audio Unit Extensions?
If writing to App Group containers is not supported, what alternatives are available?
Current entitlements:
<dict>
<key>com.apple.security.application-groups</key>
<array>
<string>group.com.<company>.<appname></string>
</array>
</dict>
I bought two "Apple USB-C to Headphone Jack Adapters". Upon closer inspection, they seems to be of different generations:
The one with product ID 0x110a on top is working fine. The one with product ID 0x110b has two issues:
There is a short but loud click noise on the headphone when I connect it to the iPad.
When I play audio using AVAudioPlayer the first half of a second or so is cut off.
Here's how I'm playing the audio:
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer?.delegate = self
audioPlayer?.prepareToPlay()
audioPlayer?.play()
Is this a known issue? Am I doing something wrong?
Hello everyone,
I am working on an app that allows you to review your own music using Apple Music. Currently I am running into an issue with the skipping forwards and backwards outside of the app.
How it should work: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song on an album should play and the information should change to reflect that in the app.
If you play a song in Apple Music, you can see a Now Playing view in the lock screen.
When you skip forward or backwards, it will do either action and it would reflect that when you see a little frequency icon on artwork image of a song.
What it's doing: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song is reflected outside of the app, but not in the app.
When skipping a song outside of the app, it works correctly to head to the next song.
But when I return to the app, it is not reflected
NOTE: I am not using MusicKit variables such as Track, Album to display the songs. Since I want to grab the songs and review them I need a rating so I created my own that grabs the MusicItemID, name, artist(s), etc.
NOTE: I am using ApplicationMusicPlayer.shared
Is there a way to get the song to reflect in my app?
(If its easier, a simple example of it would be nice. No need to create an entire xprod file)