In iOS 18, CarPlay shows an error: “There was a problem loading this content” after playback starts. Audio works fine, but the Now Playing screen doesn’t load. I’m using MPPlayableContentManager. This worked fine in iOS 17. Anyone else seeing this error in iOS 18?
Audio
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I am trying to stream audio from local filesystem.
For that, I am trying to use an AVAssetResourceLoaderDelegate for an AVURLAsset. However, Content-Length is not known at the start. To overcome this, I tried several methods:
Set content length as nil, in the AVAssetResourceLoadingContentInformationRequest
Set content length to -1, in the ContentInformationRequest
Both of these cause the AVPlayerItem to fail with an error.
I also tried setting Content-Length as INT_MAX, and setting a renewalDate = Date(timeIntervalSinceNow: 5). However, that seems to be buggy. Even after updating the Content-Length to the correct value (e.g. X bytes) and finishing that loading request, the resource loader keeps getting requests with requestedOffset = X with dataRequest.requestsAllDataToEndOfResource = true. These requests keep coming indefinitely, and as a result it seems that the next item in the queue does not get played. Also, .AVPlayerItemDidPlayToEndTime notification does not get called.
I wanted to check if this is an expected behavior or is there a bug in this implementation. Also, what is the recommended way to stream audio of unknown initial length from local file system?
Thanks!
I found that the aggregated device correctly obtains input channels in the standard microphone mode. However, in voice isolation mode, it only retrieves channels from the first sub-device in the aggregated device's list. If I want to properly obtain channel information in voice isolation mode, how should I do it?
hi all,
as soon an audio is played in a whatever app, coreaudiod inserts a sleep prevent assertion for both, the system AND the display.
can i somehow stop the insertion of the display sleep assertion?
pid 223(coreaudiod): [0x00004e9e00058dc2] 00:03:18 PreventUserIdleDisplaySleep named: "com.apple.audio.AppleGFXHDAEngineOutputDP:10001:0:{B31A-08C6-00000000}.context.preventuseridledisplaysleep"
Created for PID: 4145.
where PID 4145 is spotify.
but it doesn't matter which app is playing the audio.
any help would be appreciated
thanks
Topic:
Media Technologies
SubTopic:
Audio
When using the Apple Devices to sync Apple Music to iPhone where is the Apple Devices backup being written to?
Apple Devices->music->sync.
Not trying to backup the iPhone via Apple Devices app.
使用AVSpeechUtterance实现iOS语音播报,选择语言为简体中文“zh-CN”,读取中文“袆”(hui 第一声)错误,读成了“祎”(yi 第一声),希望能优化。
Is there any way for me to use an AutoMix api in my IOS apps, I would play tracks using the Apple Music api and use AutoMix to attempt to merge tracks.
Is this feature/api available to developers.
I am trying to get MIDI output from the AU Host demo app using the recent MIDI processor example. The processor works correctly in Logic Pro, but I cannot send MIDI from the AUv3 extension in standalone mode using the default host app to another program (e.g., Ableton).
The MIDI manager, which is part of the standalone host app, works fine, and I can send MIDI using it directly—Ableton receives it without issues. I have already set the midiOutputNames in the extension, and the midiOutBlock is mapped. However, the MIDI data from the AUv3 extension does not reach Ableton in standalone mode. I suspect the issue is that midiOutBlock might never be called in the plugin, or perhaps an input to the plugin is missing, which prevents it from sending MIDI. I am currently using the default routing.
I have modified the MIDI manager such that it works well as described above. Here is a part of my code for SimplePlayEngine.swift and my MIDIManager.swift for reference:
@MainActor
@Observable
public class SimplePlayEngine {
private let midiOutBlock: AUMIDIOutputEventBlock = { sampleTime, cable, length, data in return noErr }
var scheduleMIDIEventListBlock: AUMIDIEventListBlock? = nil
public init() {
engine.attach(player)
engine.prepare()
setupMIDI()
}
private func setupMIDI() {
if !MIDIManager.shared.setupPort(midiProtocol: MIDIProtocolID._2_0, receiveBlock: { [weak self] eventList, _ in
if let scheduleMIDIEventListBlock = self?.scheduleMIDIEventListBlock {
_ = scheduleMIDIEventListBlock(AUEventSampleTimeImmediate, 0, eventList)
}
}) {
fatalError("Failed to setup Core MIDI")
}
}
func initComponent(type: String, subType: String, manufacturer: String) async -> ViewController? {
reset()
guard let component = AVAudioUnit.findComponent(type: type, subType: subType, manufacturer: manufacturer) else {
fatalError("Failed to find component with type: \(type), subtype: \(subType), manufacturer: \(manufacturer))" )
}
do {
let audioUnit = try await AVAudioUnit.instantiate(
with: component.audioComponentDescription, options: AudioComponentInstantiationOptions.loadOutOfProcess)
self.avAudioUnit = audioUnit
self.connect(avAudioUnit: audioUnit)
return await audioUnit.loadAudioUnitViewController()
} catch {
return nil
}
}
private func startPlayingInternal() {
guard let avAudioUnit = self.avAudioUnit else { return }
setSessionActive(true)
if avAudioUnit.wantsAudioInput { scheduleEffectLoop() }
let hardwareFormat = engine.outputNode.outputFormat(forBus: 0)
engine.connect(engine.mainMixerNode, to: engine.outputNode, format: hardwareFormat)
do { try engine.start() } catch {
isPlaying = false
fatalError("Could not start engine. error: \(error).")
}
if avAudioUnit.wantsAudioInput { player.play() }
isPlaying = true
}
private func resetAudioLoop() {
guard let avAudioUnit = self.avAudioUnit else { return }
if avAudioUnit.wantsAudioInput {
guard let format = file?.processingFormat else { fatalError("No AVAudioFile defined.") }
engine.connect(player, to: engine.mainMixerNode, format: format)
}
}
public func connect(avAudioUnit: AVAudioUnit?, completion: @escaping (() -> Void) = {}) {
guard let avAudioUnit = self.avAudioUnit else { return }
engine.disconnectNodeInput(engine.mainMixerNode)
resetAudioLoop()
engine.detach(avAudioUnit)
func rewiringComplete() {
scheduleMIDIEventListBlock = auAudioUnit.scheduleMIDIEventListBlock
if isPlaying { player.play() }
completion()
}
let hardwareFormat = engine.outputNode.outputFormat(forBus: 0)
engine.connect(engine.mainMixerNode, to: engine.outputNode, format: hardwareFormat)
if isPlaying { player.pause() }
let auAudioUnit = avAudioUnit.auAudioUnit
if !auAudioUnit.midiOutputNames.isEmpty { auAudioUnit.midiOutputEventBlock = midiOutBlock }
engine.attach(avAudioUnit)
if avAudioUnit.wantsAudioInput {
engine.disconnectNodeInput(engine.mainMixerNode)
if let format = file?.processingFormat {
engine.connect(player, to: avAudioUnit, format: format)
engine.connect(avAudioUnit, to: engine.mainMixerNode, format: format)
}
} else {
let stereoFormat = AVAudioFormat(standardFormatWithSampleRate: hardwareFormat.sampleRate, channels: 2)
engine.connect(avAudioUnit, to: engine.mainMixerNode, format: stereoFormat)
}
rewiringComplete()
}
}
and my MIDI Manager
@MainActor
class MIDIManager: Identifiable, ObservableObject {
func setupPort(midiProtocol: MIDIProtocolID,
receiveBlock: @escaping @Sendable MIDIReceiveBlock) -> Bool {
guard setupClient() else { return false }
if MIDIInputPortCreateWithProtocol(client, portName, midiProtocol, &port, receiveBlock) != noErr {
return false
}
for source in self.sources {
if MIDIPortConnectSource(port, source, nil) != noErr {
print("Failed to connect to source \(source)")
return false
}
}
setupVirtualMIDIOutput()
return true
}
private func setupVirtualMIDIOutput() {
let virtualStatus = MIDISourceCreate(client, virtualSourceName, &virtualSource)
if virtualStatus != noErr {
print("❌ Failed to create virtual MIDI source: \(virtualStatus)")
} else {
print("✅ Created virtual MIDI source: \(virtualSourceName)")
}
}
func sendMIDIData(_ data: [UInt8]) {
print("hey")
var packetList = MIDIPacketList()
withUnsafeMutablePointer(to: &packetList) { ptr in
let pkt = MIDIPacketListInit(ptr)
_ = MIDIPacketListAdd(ptr, 1024, pkt, 0, data.count, data)
if virtualSource != 0 {
let status = MIDIReceived(virtualSource, ptr)
if status != noErr {
print("❌ Failed to send MIDI data: \(status)")
} else {
print("✅ Sent MIDI data: \(data)")
}
}
}
}
}
Hello there!
Is there any list of voices that are always available on iOS/iPadOS devices?
It seems that AVSpeechSynthesisVoice(identifier: "com.apple.voice.compact.en-US.Samantha") is always available on all devices.
I thought that AVSpeechSynthesisVoice(identifier: "com.apple.ttsbundle.siri_Nicky_en-US_compact") and AVSpeechSynthesisVoice(identifier: "com.apple.ttsbundle.siri_Aaron_en-US_compact") were available by default on certain newer devices. Is this true?
I also noticed that on the same iPad where I was using those 2 voices (Nicky and Aaron) - when I updated to the iPadOS 26 beta, those voices were no longer available.
Any information you can share about which voices should be reliably available on which devices would be extremely helpful for our development. Thanks so much!
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三、填写账号信息.
四、输入手机号,验证码,密码.
五、勾选用户协议,完成注册协议,完成注册.
注意:若出现账号已存在」提示,需重新设置唯一账号名称
Topic:
Media Technologies
SubTopic:
Audio
Among the millions of users of our online product, we have identified through data metrics that the silent audio data capture rate on iPadOS 18.4.1 or 18.5 has increased abnormally. However, we are unable to reproduce the issue. Has anyone encountered a similar issue? The parameters we used are as follows:
AudioSession:
category:AVAudioSessionCategoryPlayAndRecord
mode:AVAudioSessionModeDefault
option:77
preferredSampleRate:48000.000000
preferredIOBufferDuration:0.010000
AudioUnit
format.mFormatID = kAudioFormatLinearPCM;
format.mSampleRate = 48000.0;
format.mChannelsPerFrame = 2;
format.mBitsPerChannel = 16;
format.mFramesPerPacket = 1;
format.mBytesPerFrame = format.mChannelsPerFrame * 16 / 8;
format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket;
format.mFormatFlags = kAudioFormatFlagsNativeEndian | kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger;
component.componentType = kAudioUnitType_Output;
component.componentSubType = kAudioUnitSubType_RemoteIO;
component.componentManufacturer = kAudioUnitManufacturer_Apple;
component.componentFlags = 0;
component.componentFlagsMask = 0;
Hello,
I'm evaluating the Apple Music Feed dataset and I noticed that the total number of songs available in the feed is too small. As of today, the number of objects returned in each feed is:
51,198,712 albums
23,093,698 artists
173,235,315 songs
This gives an average of 3.38 songs per album which is quite low. Also, iterating on the data I see that there are albums referencing songs that don't exist in the songs feed. I would like to know:
Is the feed data incomplete?
If so, in what situations an object may be missing from the feed?
Thank you in advance!
We’ve encountered a reproducible issue where the iPhone fails to reconnect to a Wi-Fi access point under the following conditions:
The device is connected to a 2.4GHz Wi-Fi network.
A Bluetooth audio accessory is connected (e.g. headset).
AVAudioSession is active (such as during a voice call or when using the Voice Memos app).
The user moves away from the access point, causing a disconnect.
Upon returning within range, the access point is no longer recognized or reconnected while AVAudioSession remains active.
However, if the Bluetooth device is disconnected or the AVAudioSession is deactivated, the Wi-Fi access point is immediately recognized again.
We confirmed this behavior not only in my app but also using Apple's built-in Voice Memos app, suggesting this is not specific to our implementation.
It appears that the Wi-Fi system deprioritizes reconnection while AVAudioSession is engaged. Could this be by design? Or is this a known issue or limitation with Wi-Fi and AVAudioSession interaction?
Test Environment:
Device: iPhone 13 mini
iOS: 17.5.1
Wi-Fi: 2.4GHz band
Accessories: Bluetooth headset
We’d appreciate clarification on whether this is expected behavior or a bug. Thank you!
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?
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!}
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 have a new 2725QC (Dell) Monitor that uses USB-C connection to connect with the iMac (2019, 27 inch) through the back port but the problem is that the volume control can currently only be done from the hardware, not the software control using the Apple keyboard. What should I do in terms of writing code to do this (Swift or Obj-C)? Is there a third-party solution for Intel iMac and ARM Mac?
My app - natively iOS but built with the "Designed for iPad" option to run on Mac - does not recognise an attached USB microphone when running on a Mac. This line
int32_t items = (int32_t) [[[AVAudioSession sharedInstance] availableInputs] count ];
returns 1, which is the Mac internal mic. On iPad and iPhone it sees both the internal mic and the USB mic. Is this an inherent "Designed for iPad" restriction, and is there some trick I can pull to get the USB microphone to be recognised by the system?
Topic:
Media Technologies
SubTopic:
Audio
Hi, I'm trying to plan out development of an app and am wondering if it is possible to have user generated content automatically populate into a custom shazamkit catalogue and be able to query this catalogue non-locally?
Storing all the submissions locally would obviously not scale.
I'm working on a v2 Audio Unit that has some complicated internal state (audio, midi, other settings).
When the internal state changes, I want to inform the host (f.i. Logic Pro) that my plugin state has changed, and that the main window should show the 'project changed' status through the window close button.
This was easy to achieve for the VST version of the plugin, but I can't figure out a way to do it for the Audio Unit.
I've tried:
Notifying change of the kAudioUnitProperty_ClassInfo property that stores the plugin state:
unit->PropertyChanged(kAudioUnitProperty_ClassInfo, kAudioUnitScope_Global, 0);
Setting the kAudioUnitProperty_ClassInfo property value each time the plugin state changes.
Adding a new parameter called 'dirtystate' and toggling it and notifying the change each time the plugin state changes.
But nothing really make Logic take notice. This should be an easy task, but I can't put my finger on it.
How do I flag may AUv2 as needing its status saved (i.e. the host project needs saving)?