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!}
Audio
RSS for tagDive into the technical aspects of audio on your device, including codecs, format support, and customization options.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
Hi everyone,
I’m testing audio recording on an iPhone 15 Plus using AVFoundation.
Here’s a simplified version of my setup:
let settings: [String: Any] = [
AVFormatIDKey: Int(kAudioFormatLinearPCM),
AVSampleRateKey: 8000,
AVNumberOfChannelsKey: 1,
AVLinearPCMBitDepthKey: 16,
AVLinearPCMIsFloatKey: false
]
audioRecorder = try AVAudioRecorder(url: fileURL, settings: settings)
audioRecorder?.record()
When I check the recorded file’s sample rate, it logs:
Actual sample rate: 8000.0
However, when I inspect the hardware sample rate:
try session.setCategory(.playAndRecord, mode: .default)
try session.setActive(true)
print("Hardware sample rate:", session.sampleRate)
I consistently get:
`Hardware sample rate: 48000.0
My questions are:
Is the iPhone mic actually capturing at 8 kHz, or is it recording at 48 kHz and then downsampling to 8 kHz internally?
Is there any way to force the hardware to record natively at 8 kHz?
If not, what’s the recommended approach for telephony-quality audio (true 8 kHz) on iOS devices?
Thanks in advance for your guidance!
3
I am working on an application to get when input audio device is being used. Basically I want to know the application using the microphone (built-in or external)
This app runs on macOS. For Mac versions starting from Sonoma I can use this code:
int getAudioProcessPID(AudioObjectID process)
{
pid_t pid;
if (@available(macOS 14.0, *)) {
constexpr AudioObjectPropertyAddress prop {
kAudioProcessPropertyPID,
kAudioObjectPropertyScopeGlobal,
kAudioObjectPropertyElementMain
};
UInt32 dataSize = sizeof(pid);
OSStatus error = AudioObjectGetPropertyData(process, &prop, 0, nullptr, &dataSize, &pid);
if (error != noErr) {
return -1;
}
} else {
// Pre sonoma code goes here
}
return pid;
}
which works.
However, kAudioProcessPropertyPID was added in macOS SDK 14.0.
Does anyone know how to achieve the same functionality on previous versions?
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)")
}
}
}
}
}
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.
Please Update Andorid MusicKit,the version 1.1.2 will complied fail。the error msg:•SDKUriHandlerActivity>. Apps targeting Android 12 and higher are required to specify an explicit value for android:exported when the corres
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
Hi folks - I'm having trouble finding specific documentation about Audio Unit MIDI plugins - as in MIDI -only. Any suggestions welcome as searches aren't returning much. (too niche? user error?)
Topic:
Media Technologies
SubTopic:
Audio
Hi everyone,
I’m trying to use AVAssetResourceLoaderDelegate to handle a live radio stream (e.g. Icecast/HTTP stream). My goal is to have access to the last 30 seconds of audio data during playback, so I can analyze it for specific audio patterns in near-real-time.
I’ve implemented a custom resource loader that works fine for podcasts and static files, where the file size and content length are known. However, for infinite live streams, my current implementation stops receiving new loading requests after the first one is served. As a result, the playback either stalls or fails to continue.
Has anyone successfully used AVAssetResourceLoaderDelegate with a continuous radio stream? Or maybe you can suggest betterapproach for buffering and analyzing live audio?
Any tips, examples, or advice would be appreciated. Thanks!
I'm trying to write 16-bit interleaved 2-channel data captured from a LiveSwitch audio source to a AVAudioFile. The buffer and file formats match but I get a bad parameter error from the API. Does this API not support the specified format or is there some other issue?
Here is the debugger output.
(lldb) po audioFile.url
▿ file:///private/var/mobile/Containers/Data/Application/1EB14379-0CF2-41B6-B742-4C9A80728DB3/tmp/Heart%20Sounds%201
- _url : file:///private/var/mobile/Containers/Data/Application/1EB14379-0CF2-41B6-B742-4C9A80728DB3/tmp/Heart%20Sounds%201
- _parseInfo : nil
- _baseParseInfo : nil
(lldb) po error
Error Domain=com.apple.coreaudio.avfaudio Code=-50 "(null)" UserInfo={failed call=ExtAudioFileWrite(_impl->_extAudioFile, buffer.frameLength, buffer.audioBufferList)}
(lldb) po buffer.format
<AVAudioFormat 0x302a12b20: 2 ch, 44100 Hz, Int16, interleaved>
(lldb) po audioFile.fileFormat
<AVAudioFormat 0x302a515e0: 2 ch, 44100 Hz, Int16, interleaved>
(lldb) po buffer.frameLength
882
(lldb) po buffer.audioBufferList
▿ 0x0000000300941e60
- pointerValue : 12894608992
This code handles the details of converting the Live Switch frame into an AVAudioPCMBuffer.
extension FMLiveSwitchAudioFrame {
func convertedToPCMBuffer() -> AVAudioPCMBuffer {
Self.convertToAVAudioPCMBuffer(from: self)!
}
static func convertToAVAudioPCMBuffer(from frame: FMLiveSwitchAudioFrame) -> AVAudioPCMBuffer? {
// Retrieve the audio buffer and format details from the FMLiveSwitchAudioFrame
guard
let buffer = frame.buffer(),
let format = buffer.format() as? FMLiveSwitchAudioFormat else { return nil }
// Extract PCM format details from FMLiveSwitchAudioFormat
let sampleRate = Double(format.clockRate())
let channelCount = AVAudioChannelCount(format.channelCount())
// Determine bytes per sample based on bit depth
let bitsPerSample = 16
let bytesPerSample = bitsPerSample / 8
let bytesPerFrame = bytesPerSample * Int(channelCount)
let frameLength = AVAudioFrameCount(Int(buffer.dataBuffer().length()) / bytesPerFrame)
// Create an AVAudioFormat from the FMLiveSwitchAudioFormat
guard let avAudioFormat = AVAudioFormat(commonFormat: .pcmFormatInt16, sampleRate: sampleRate, channels: channelCount, interleaved: true) else {
return nil
}
// Create an AudioBufferList to wrap the existing buffer
let audioBufferList = UnsafeMutablePointer<AudioBufferList>.allocate(capacity: 1)
audioBufferList.pointee.mNumberBuffers = 1
audioBufferList.pointee.mBuffers.mNumberChannels = channelCount
audioBufferList.pointee.mBuffers.mDataByteSize = UInt32(buffer.dataBuffer().length())
audioBufferList.pointee.mBuffers.mData = buffer.dataBuffer().data().mutableBytes // Directly use LiveSwitch buffer
// Transfer ownership of the buffer to AVAudioPCMBuffer
let pcmBuffer = AVAudioPCMBuffer(pcmFormat: avAudioFormat, bufferListNoCopy: audioBufferList) /* { buffer in
// Ensure the buffer is freed when AVAudioPCMBuffer is deallocated
buffer.deallocate() // Only call this if LiveSwitch allows manual deallocation
} */
pcmBuffer?.frameLength = frameLength
return pcmBuffer
}
}
This is the handler that is invoked with every frame in order to convert it for use with AVAudioFile and optionally update a scrolling signal display on the screen.
private func onRaisedFrame(obj: Any!) -> Void {
// Bail out early if no one is interested in the data.
guard isMonitoring else { return }
// Convert LS frame to AVAudioPCMBuffer (no-copy)
let frame = obj as! FMLiveSwitchAudioFrame
let buffer = frame.convertedToPCMBuffer()
// Hand subscribers a reference to the buffer for rendering to display.
bufferPublisher?.send(buffer)
// If we have and output file, store the data there, as well.
guard let audioFile = self.audioFile else { return }
do {
try audioFile.write(from: buffer) // FIXME: This call is throwing error -50
} catch {
FMLiveSwitchLog.error(withMessage: "Failed to write buffer to audio file at \(audioFile.url): \(error)")
self.audioFile = nil
}
}
This is how the audio file is being setup.
static var recordingFormat: AVAudioFormat = {
AVAudioFormat(commonFormat: .pcmFormatInt16, sampleRate: 44_100, channels: 2, interleaved: true)!
}()
let audioFile = try AVAudioFile(forWriting: outputURL, settings: Self.recordingFormat.settings)
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 :)
Hi all,
i can successfully match music using shazamkit on Apple using SwiftUI, a simple app that let user to load an audio file and exctracts the relative match, while i am unable to match music using shamzamkit on Android. I am trying to make the same simple app but i cannot match music as i get MATCH_ATTEMPT_FAILED every time i try to. I don't know what i am doing wrong but the shazam part in the kotlin Android code is in this method :
suspend fun processAudioFileInBackground(
filePath: String,
developerTokenProvider: DeveloperTokenProvider
) = withContext(Dispatchers.IO) {
val bufferSize = 1024 * 1024
val audioFile = FileInputStream(filePath)
val byteBuffer = ByteBuffer.allocate(bufferSize)
byteBuffer.order(ByteOrder.LITTLE_ENDIAN)
var bytesRead: Int
while (audioFile.read(byteBuffer.array()).also { bytesRead = it } != -1) {
val signatureGenerator = (ShazamKit.createSignatureGenerator(AudioSampleRateInHz.SAMPLE_RATE_44100) as ShazamKitResult.Success).data
signatureGenerator.append(byteBuffer.array(), bytesRead, System.currentTimeMillis())
val signature = signatureGenerator.generateSignature()
println("Signature: ${signature.durationInMs}")
val catalog = ShazamKit.createShazamCatalog(developerTokenProvider, Locale.ENGLISH)
val session = (ShazamKit.createSession(catalog) as ShazamKitResult.Success).data
val matchResult = session.match(signature)
println("MatchResult : $matchResult")
setMatchResult(matchResult)
byteBuffer.clear()
}
audioFile.close()
}
I noticed that changing Locale in catalog creation results in different result as i get NoMatch without exception. Can you please help me with this?
Topic:
Media Technologies
SubTopic:
Audio
On Apple TV 4K 3rd generation, with tvOS 26 beta 2, when two HomePod 2 are paired to the device, music and movie sources with Dolby Atmos can only be listened to in stereo. dolby atmos not supported
Topic:
Media Technologies
SubTopic:
Audio
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.
Hello everyone,
I’m new to Swift development and have been working on an audio module that plays a specific sound at regular intervals - similar to a workout timer that signals switching exercises every few minutes.
Following AVFoundation documentation, I’m configuring my audio session like this:
let session = AVAudioSession.sharedInstance()
try session.setCategory(
.playback,
mode: .default,
options: [.interruptSpokenAudioAndMixWithOthers, .duckOthers]
)
self.engine.attach(self.player)
self.engine.connect(self.player, to: self.engine.outputNode, format: self.audioFormat)
try? session.setActive(true)
When it’s time to play cues, I schedule playback on a DispatchQueue:
// scheduleAudio uses DispatchQueue
self.scheduleAudio(at: interval.start) {
do {
try audio.engine.start()
audio.node.play()
for sample in interval.samples {
audio.node.scheduleBuffer(sample.buffer, at: AVAudioTime(hostTime: sample.hostTime))
}
} catch {
print("Audio activation failed: \(error)")
}
}
This works perfectly in the foreground. But once the app goes into the background, the scheduled callback runs, yet the audio engine fails to start, resulting in an error with code 561015905.
Interestingly, if the app is already playing audio before going to the background, the scheduled sounds continue to play as expected.
I have added the required background audio mode to my Info plist file by including the key UIBackgroundModes with the value audio.
Is there anything else I should configure? What is the best practice to play periodic audio when the app runs in the background? How do apps like turn-by-turn navigation handle continuous audio playback in the background?
Any advice or pointers would be greatly appreciated!
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!
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
Hi, everyone, I downloaded the source code EditingSpatialAudioWithAnAudioMix.zip from https://developer.apple.com/documentation/Cinematic/editing-spatial-audio-with-an-audio-mix, when I carried out one of the actions named "process" in command line the program crashed!!
Form the source code, I found that the value of componentType is set to kAudioUnitType_FormatConverter:
// The actual `AudioUnit`.
public var auAudioMix = AVAudioUnitEffect()
init() {
// Generate a component description for the audio unit.
let componentDescription = AudioComponentDescription(
componentType: kAudioUnitType_FormatConverter,
componentSubType: kAudioUnitSubType_AUAudioMix,
componentManufacturer: kAudioUnitManufacturer_Apple,
componentFlags: 0,
componentFlagsMask: 0)
auAudioMix=AVAudioUnitEffect(audioComponentDescription: componentDescription)
}
But in the document from https://developer.apple.com/documentation/avfaudio/avaudiouniteffect/init(audiocomponentdescription:), it seems that componentType can not be set to kAudioUnitType_FormatConverter and :
Has everyone encountered this problem?
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.
I have the new iOS 26 SpeechTranscriber working in my application. The issue I am facing is how to determine if the device I am running on supports SpeechTranscriber. I was able to create code that tests if the device supports transcription but it takes a bit of time to run and thus the results are not available when the app launches. What I am looking for is a list of what iOS 26 devices it doesn't run on. I think its safe to assume any new devices will support it so if we can just have a list of what devices that can run iOS 26 and not able to do transcription it would be much faster for the app. I have determined it doesn't work on a SE 2nd Gen, it works on iPhone 12, SE 3rd Gen, iPhone 14 Pro, 15 Pro. As the SpeechTranscriber doesn't work in the simulator I can't determine that way. I have checked the docs and it doesn't list the devices it doesn't work on.