A recent WWDC session "Learn about Apple Immersive Video technologies" showed a Apple Spatial Audio Format Panner plugin for Pro Tools. The presenter stated that it's available on a per-user license.
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Audio
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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
Good day, ladies and gents.
I have an application that reads audio from the microphone. I'd like it to also be able to read from the Mac's audio output stream. (A bonus would be if it could detect when the Mac is playing music.)
I'd eventually be able to figure it out reading docs, but if someone can give a hint, I'd be very grateful, and would owe you the libation of your choice.
Here's the code used to set up the AudioUnit:
-(NSString*) configureAU
{
AudioComponent component = NULL;
AudioComponentDescription description;
OSStatus err = noErr;
UInt32 param;
AURenderCallbackStruct callback;
if( audioUnit ) { AudioComponentInstanceDispose( audioUnit ); audioUnit = NULL; } // was CloseComponent
// Open the AudioOutputUnit
description.componentType = kAudioUnitType_Output;
description.componentSubType = kAudioUnitSubType_HALOutput;
description.componentManufacturer = kAudioUnitManufacturer_Apple;
description.componentFlags = 0;
description.componentFlagsMask = 0;
if( component = AudioComponentFindNext( NULL, &description ) )
{
err = AudioComponentInstanceNew( component, &audioUnit );
if( err != noErr ) { audioUnit = NULL; return [ NSString stringWithFormat: @"Couldn't open AudioUnit component (ID=%d)", err] ; }
}
// Configure the AudioOutputUnit:
// You must enable the Audio Unit (AUHAL) for input and output for the same device.
// When using AudioUnitSetProperty the 4th parameter in the method refers to an AudioUnitElement.
// When using an AudioOutputUnit for input the element will be '1' and the output element will be '0'.
param = 1; // Enable input on the AUHAL
err = AudioUnitSetProperty( audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, ¶m, sizeof(UInt32) ); chkerr("Couldn't set first EnableIO prop (enable inpjt) (ID=%d)");
param = 0; // Disable output on the AUHAL
err = AudioUnitSetProperty( audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, ¶m, sizeof(UInt32) ); chkerr("Couldn't set second EnableIO property on the audio unit (disable ootpjt) (ID=%d)");
param = sizeof(AudioDeviceID); // Select the default input device
AudioObjectPropertyAddress OutputAddr = { kAudioHardwarePropertyDefaultInputDevice, kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster };
err = AudioObjectGetPropertyData( kAudioObjectSystemObject, &OutputAddr, 0, NULL, ¶m, &inputDeviceID );
chkerr("Couldn't get default input device (ID=%d)");
// Set the current device to the default input unit
err = AudioUnitSetProperty( audioUnit, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, &inputDeviceID, sizeof(AudioDeviceID) );
chkerr("Failed to hook up input device to our AudioUnit (ID=%d)");
callback.inputProc = AudioInputProc; // Setup render callback, to be called when the AUHAL has input data
callback.inputProcRefCon = self;
err = AudioUnitSetProperty( audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &callback, sizeof(AURenderCallbackStruct) );
chkerr("Could not install render callback on our AudioUnit (ID=%d)");
param = sizeof(AudioStreamBasicDescription); // get hardware device format
err = AudioUnitGetProperty( audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 1, &deviceFormat, ¶m );
chkerr("Could not install render callback on our AudioUnit (ID=%d)");
audioChannels = MAX( deviceFormat.mChannelsPerFrame, 2 ); // Twiddle the format to our liking
actualOutputFormat.mChannelsPerFrame = audioChannels;
actualOutputFormat.mSampleRate = deviceFormat.mSampleRate;
actualOutputFormat.mFormatID = kAudioFormatLinearPCM;
actualOutputFormat.mFormatFlags = kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved;
if( actualOutputFormat.mFormatID == kAudioFormatLinearPCM && audioChannels == 1 )
actualOutputFormat.mFormatFlags &= ~kLinearPCMFormatFlagIsNonInterleaved;
#if __BIG_ENDIAN__
actualOutputFormat.mFormatFlags |= kAudioFormatFlagIsBigEndian;
#endif
actualOutputFormat.mBitsPerChannel = sizeof(Float32) * 8;
actualOutputFormat.mBytesPerFrame = actualOutputFormat.mBitsPerChannel / 8;
actualOutputFormat.mFramesPerPacket = 1;
actualOutputFormat.mBytesPerPacket = actualOutputFormat.mBytesPerFrame;
// Set the AudioOutputUnit output data format
err = AudioUnitSetProperty( audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &actualOutputFormat, sizeof(AudioStreamBasicDescription));
chkerr("Could not change the stream format of the output device (ID=%d)");
param = sizeof(UInt32); // Get the number of frames in the IO buffer(s)
err = AudioUnitGetProperty( audioUnit, kAudioDevicePropertyBufferFrameSize, kAudioUnitScope_Global, 0, &audioSamples, ¶m );
chkerr("Could not determine audio sample size (ID=%d)");
err = AudioUnitInitialize( audioUnit ); // Initialize the AU
chkerr("Could not initialize the AudioUnit (ID=%d)");
// Allocate our audio buffers
audioBuffer = [self allocateAudioBufferListWithNumChannels: actualOutputFormat.mChannelsPerFrame size: audioSamples * actualOutputFormat.mBytesPerFrame];
if( audioBuffer == NULL ) { [ self cleanUp ]; return [NSString stringWithFormat: @"Could not allocate buffers for recording (ID=%d)", err]; }
return nil;
}
(...again, it would be nice to know if audio output is active and thereby choose the clean output stream over the noisy mic, but that would be a different chunk of code, and my main question may just be a quick edit to this chunk.)
Thanks for your attention! ==Dave
[p.s. if i get more than one useful answer, can i "Accept" more than one, to spread the credit around?]
{pps: of course, the code lines up prettier in a monospaced font!}
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
Your draft looks great! Here's a refined version with the iOS 17 comparison emphasized and slightly better flow:
Hi Apple Engineers and fellow developers,
I'm experiencing a critical regression with ShazamKit's background operation on iOS 18. ShazamKit's SHManagedSession stops identifying songs in the background after approximately 20 seconds on iOS 18, while the exact same code works perfectly on iOS 17.
The behavior is consistent: the app works perfectly in the foreground, but when backgrounded or device is locked, it initially works for about 20 seconds then stops identifying new songs. The microphone indicator remains active suggesting audio access is maintained, but ShazamKit doesn't send identified songs in the background until you open the app again. Detection immediately resumes when bringing the app to foreground.
My technical setup uses SHManagedSession for continuous matching with background modes properly configured in Info.plist including audio mode, and Background App Refresh enabled. I've tested this on physical devices running iOS 18.0 through 18.5 with the same results across all versions. The exact same code running on iOS 17 devices works flawlessly in the background.
To reproduce: initialize SHManagedSession and start matching, begin song identification in foreground, background the app or lock device, play different songs which are initially detected for about 20 seconds, then after the timeout period new songs are no longer identified until you bring the app to foreground.
This regression has impacted my production app as users who rely on continuous background music identification are experiencing a broken feature. I submitted this as Feedback ID FB15255903 last September with no solution so far.
I've created a minimal demo project that reproduces this issue: https://github.com/tfmart/ShazamKitBackground
Has anyone else experienced this ShazamKit background regression on iOS 18? Are there any known workarounds or alternative approaches? Given the time this issue has persisted, could we please get acknowledgment of this regression, expected timeline for a fix, or any recommended workarounds?
Testing environment is Xcode 16.0+ on iOS 18.0-18.5 across multiple physical device models.
Any guidance would be greatly appreciated.
Hello,
I have a CarPlay Navigation app and utilize the AVSpeechSynthesizer to speak directions to a user. Everything works great on my CarPlay simulator as well as when plugged into my GMC truck. However, I found out yesterday that one of my users with a Ford truck the audio would cut in an out.
After much troubleshooting, I was able to replicate this on my own truck when using Bluetooth to connect to CarPlay. My user was also utilizing Bluetooth. Has anyone else experienced this? Is there a fix to the problem?
import SwiftUI
import AVFoundation
class TextToSpeechService: NSObject, ObservableObject, AVSpeechSynthesizerDelegate {
private var speechSynthesizer = AVSpeechSynthesizer()
static let shared = TextToSpeechService()
override init() {
super.init()
speechSynthesizer.delegate = self
}
func configureAudioSession() {
speechSynthesizer.delegate = self
do {
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .voicePrompt, options: [.mixWithOthers, .allowBluetooth])
} catch {
print("Failed to set audio session category: \(error.localizedDescription)")
}
}
func speak(_ text: String) {
Task(priority: .high) {
let speechUtterance = AVSpeechUtterance(string: text)
speechUtterance.voice = AVSpeechSynthesisVoice(language: AVSpeechSynthesisVoice.currentLanguageCode())
try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
speechSynthesizer.speak(speechUtterance)
}
}
func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) {
Task {
stopSpeech()
try AVAudioSession.sharedInstance().setActive(false)
}
}
func stopSpeech() {
speechSynthesizer.stopSpeaking(at: .immediate)
}
}
Hi,
I am creating an app that can include videos or images in it's data. While
@Attribute(.externalStorage)
helps with images, with AVAssets I actually would like access to the URL behind that data. (as it would be stupid to load and then save the data again just to have a URL)
One key component is to keep all of this clean enough so that I can use (private) CloudKit syncing with the resulting model.
All the best
Christoph
AVAudioFormat has no Swift concurrency annotations but the documentation states "Instances of this class are immutable."
This made me always assume it was safe to pass AVAudioFormat instances around. Is this the case? If so can it be marked as Sendable? Am I missing something?
The device is connected to Bluetooth A and Bluetooth B, currently the audio is played through Bluetooth A, click the interface button, how to realize the code to switch to Bluetooth B?
Hi,
I try to record audio on the iPhone with the AVAudioRecorder and Xcode 26.0.1.
Maybe the problem is that I can not record audio with the simulator. But there's a menu for audio.
In the plist I added 'Privacy - Microphone Usage Description' and I ask for permission before recording.
if await AVAudioApplication.requestRecordPermission() {
print("permission granted")
recordPermission = true
} else {
print("permission denied")
}
Permission is granted.
let settings: [String : Any] = [
AVFormatIDKey: kAudioFormatMPEG4AAC,
AVSampleRateKey: 12000,
AVNumberOfChannelsKey: 1,
AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue
]
recorder = try AVAudioRecorder(url: filename, settings: settings)
let prepared = recorder.prepareToRecord()
print("prepared started: \(prepared)")
let started = recorder.record()
print("recording started: \(started)")
started is always false and I tried many settings.
Error messages
AddInstanceForFactory: No factory registered for id <CFUUID 0x600000211480> F8BB1C28-BAE8-11D6-9C31-00039315CD46
AudioConverter.cpp:1052 Failed to create a new in process converter -> from 0 ch, 12000 Hz, .... (0x00000000) 0 bits/channel, 0 bytes/packet, 0 frames/packet, 0 bytes/frame to 1 ch, 12000 Hz, aac (0x00000000) 0 bits/channel, 0 bytes/packet, 1024 frames/packet, 0 bytes/frame, with status -50
AudioQueueObject.cpp:1892 BuildConverter: AudioConverterNew returned -50
from: 0 ch, 12000 Hz, .... (0x00000000) 0 bits/channel, 0 bytes/packet, 0 frames/packet, 0 bytes/frame
to: 1 ch, 12000 Hz, aac (0x00000000) 0 bits/channel, 0 bytes/packet, 1024 frames/packet, 0 bytes/frame
prepared started: true
AudioQueueObject.cpp:7581 ConvertInput: aq@0x10381be00: AudioConverterFillComplexBuffer returned -50, packetCount 5
recording started: false
All examples I find are the same, but apparently there must be something different.
I'm using an AVAudioConverter object to decode an OPUS stream for VoIP. The decoding itself works well, however, whenever the stream stalls (no more audio packet is available to decode because of network instability) this can be heard in crackling / abrupt stop in decoded audio. OPUS can mitigate this by indicating packet loss by passing a null pointer in the C-library to
int opus_decode_float (OpusDecoder * st, const unsigned char * data, opus_int32 len, float * pcm, int frame_size, int decode_fec), see https://opus-codec.org/docs/opus_api-1.2/group__opus__decoder.html#ga9c554b8c0214e24733a299fe53bb3bd2.
However, with AVAudioConverter using Swift I'm constructing an AVAudioCompressedBuffer like so:
let compressedBuffer = AVAudioCompressedBuffer(
format: VoiceEncoder.Constants.networkFormat,
packetCapacity: 1,
maximumPacketSize: data.count
)
compressedBuffer.byteLength = UInt32(data.count)
compressedBuffer.packetCount = 1
compressedBuffer.packetDescriptions!
.pointee.mDataByteSize = UInt32(data.count)
data.copyBytes(
to: compressedBuffer.data
.assumingMemoryBound(to: UInt8.self),
count: data.count
)
where data: Data contains the raw OPUS frame to be decoded.
How can I specify data loss in this context and cause the AVAudioConverter to output PCM data whenever no more input data is available?
More context:
I'm specifying the audio format like this:
static let frameSize: UInt32 = 960
static let sampleRate: Float64 = 48000.0
static var networkFormatStreamDescription =
AudioStreamBasicDescription(
mSampleRate: sampleRate,
mFormatID: kAudioFormatOpus,
mFormatFlags: 0,
mBytesPerPacket: 0,
mFramesPerPacket: frameSize,
mBytesPerFrame: 0,
mChannelsPerFrame: 1,
mBitsPerChannel: 0,
mReserved: 0
)
static let networkFormat =
AVAudioFormat(
streamDescription:
&networkFormatStreamDescription
)!
I've tried 1) setting byteLength and packetCount to zero and 2) returning nil but setting .haveData in the AVAudioConverterInputBlock I'm using with no success.
iOS 26.0 (23A5276f) – Bluetooth Call Audio Issue
I’m experiencing a Bluetooth audio issue on iOS 26.0 (build 23A5276f). I cannot make or receive phone calls properly using Bluetooth devices — this affects both my car’s Bluetooth system and my AirPods Pro (2nd generation).
Notably:
Regular phone calls have no audio (either I can’t hear the other person, or they can’t hear me).
WhatsApp and other VoIP apps work fine with the same Bluetooth devices.
Media playback (music, video, etc.) works without issues over Bluetooth.
It seems this bug is limited to the native Phone app or the system audio routing for regular cellular calls. Please advise if this is a known issue or if a fix is expected in upcoming beta releases.
Since the last update to IOS 26.0 (23A5276f) the AirPods connect to my IPhone and the Audio is still running through the phone. They are shown in the Bluetooth Icon that they’re paired.
Topic:
Media Technologies
SubTopic:
Audio
I have a bunch of Audio Unit v3 plugins that are approaching release, and I was considering using subscription-model pricing, as I have done in a soon to be released iOS app. However, whether this is possible or not is not at all obvious. Specifically:
The plugin can, depending on the host app, be loaded in-process or out-of-process - yes, I know, Logic Pro and Garage Band will not load a plug-in in-process anymore, but I am not going to rule that out for other audio apps and force on them the overhead of IPC (I spent two solid weeks deciphering the process to actually make it possible for an AUv3 to run in-process - see this - https://github.com/timboudreau/audio_unit_rust_demo - example with notes)
Depending on how it is loaded, the value of Bundle.main.bundleIdentifier will vary. If I use the StoreKit API, will that return product results for my bundle identifier when being called as a library from a foreign application? I would expect it would be a major security hole if random apps could query about purchases of other random apps, so I assume not.
Even if I restricted the plugins to running out-of-process, I have to set up the in-app purchases on the app store for the App container's ID, not the extension's ID, and the extension is what run - the outer app that is what you purchase is just a toy demo that exists solely to register the audio unit.
I have similar questions with regard to MetricKit, which I would similarly like to use, but which may be running inside some random app.
If there were some sort of signed token, or similar mechanism, that could be bundled or acquired by the running plugin extension that could be used to ensure both StoreKit and MetricKit operate under the assumption that purchases and metrics should be accessed as if called from the container app, that would be very helpful.
This is the difference between having a one-and-done sales model and something that provides ongoing revenue to maintain these products - I am a one-person shop - if I price these products where they would need to be to pay the bills assuming a single sale per customer ever, the price will be too high for anyone to want to try products from a small vendor they've never heard of. So, being able to do a free trial period and then subscription is the difference between this being a viable business or not.
I’m facing a strange audio routing issue that seems specific to iPhone 14 Pro / Pro Max.
I’m using LiveKit (WebRTC) in a React Native app, which uses AVAudioSession internally for audio capture (VoIP / call-style usage).
🔍 What’s happening:
I’m using an external USB microphone.
On these devices:
iPhone 11 → ✅ USB mic works
iPhone 13 → ✅ USB mic works
iPhone 17 Pro → ✅ USB mic works
iPhone 14 Pro Max → ❌ USB mic does NOT work
On iPhone 14 Pro Max:
The same USB mic:
✅ Works in Voice Memos
✅ Works in Instagram Live
❌ Does NOT appear as an input option in my app
❌ Does NOT work in WhatsApp / Instagram calls
Also:
In my app on iPhone 14 Pro Max, iOS does not show the audio input selector UI
On iPhone 17 Pro, the same app and same build does show the selector and the USB mic works
⚙️ My audio session config ( LiveKit ):
await AudioSession.setAppleAudioConfiguration({
audioCategory: 'playAndRecord',
audioMode: 'default',
audioCategoryOptions: ['allowBluetooth', 'defaultToSpeaker'],
});
await AudioSession.startAudioSession();
❓ My questions:
Is this a known limitation or behavior specific to iPhone 14 Pro / Pro Max?
Does iPhone 14 Pro have different audio routing rules for call / VoIP mode compared to other devices?
Why does the same USB mic work in recording apps (Voice Memos, Instagram Live) but not in call-style apps (LiveKit, WhatsApp, Instagram call)?
Is there any documented difference in AVAudioSession behavior on iPhone 14 Pro regarding external USB audio inputs?
My workout watch app supports audio playback during exercise sessions.
When users carry both Apple Watch, iPhone, and AirPods, with AirPods connected to the iPhone, I want to route audio from Apple Watch to AirPods for playback. I've implemented this functionality using the following code.
try? session.setCategory(.playback, mode: .default, policy: .longFormAudio, options: [])
try await session.activate()
When users are playing music on iPhone and trigger my code in the watch app, Apple Watch correctly guides users to select
AirPods, pauses the iPhone's music, and plays my audio.
However, when playback finishes and I end the session using the code below:
try session.setActive(false, options:[.notifyOthersOnDeactivation])
the iPhone
doesn't automatically resume the previously interrupted music playback—it requires manual intervention.
Is this expected behavior, or am I missing other important steps in my code?
How does a third party developer go about supporting the new Enhanced Dialogue option for video apps in tvOS 18?
If an app is using the standard AVPlayerViewController, I had assumed it would be a simple-ish matter of building against the tvOS 18 SDK but apparently not, the options don't appear, not even greyed out.
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.
Hello!
I've two mics connected to a USB-hub. The USB-hub is then connected to my iPad. Both mics are part of the audio session's list of available inputs.
The problem is that regardless of which mic I select in my app (using setPreferredInput() on the audio session), the audio keeps coming from the mic that was last connected to the USB-hub.
Anyone that knows if this is a limitation in iPadOS/iOS?
Topic:
Media Technologies
SubTopic:
Audio
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.