Hi all,
with my app ScreenFloat, you can record your screen, along with system- and microphone audio.
Those two audio feeds are recorded into separate audio tracks in order to individually remove or edit them later on.
Now, these recordings you create with ScreenFloat can be drag-and-dropped to other apps instantly. So far, so good, but some apps, like Slack, or VLC, or even websites like YouTube, do not play back multiple audio tracks, just one.
So what I'm trying to do is, on dragging the video recording file out of ScreenFloat, instantly baking together the two individual audio tracks into one, and offering that new file as the drag and drop file, so that all audio is played in the target app.
But it's slow. I mean, it's actually quite fast, but for drag and drop, it's slow.
My approach is this:
"Bake together" the two audio tracks into a one-track m4a audio file using AVMutableAudioMix and AVAssetExportSession
Take the video track, add the new audio file as an audio track to it, and render that out using AVAssetExportSession
For a quick benchmark, a 3'40'' movie, step 1 takes ~1.7 seconds, and step two adds another ~1.5 seconds, so we're at ~3.2 seconds. That's an eternity for a drag and drop, where the user might cancel if there's no immediate feedback.
I could also do it in one step, but then I couldn't use the AV*Passthrough preset, and that makes it take around 32 seconds then, because I assume it touches the video data (which is unnecessary in this case, so I think the two-step approach here is the fastest).
So, my question is, is there a faster way?
The best idea I can come up with right now is, when initially recording the screen with system- and microphone audio as separate tracks, to also record both of them into a third, muted, "hidden" track I could use later on, basically eliminating the need for step one and just ripping the two single audio tracks out of the movie and only have the video and the "hidden" track (then unmuted), but I'd still have a ~1.5 second delay there. Also, there's the processing and data overhead (basically doubling the movie's audio data).
All this would be great for an export operation (where one expects it to take a little time), but for a drag-and-drop operation, it's not ideal.
I've discarded the idea of doing a promise file drag, because many apps do not accept those, and I want to keep wide compatibility with all sorts of apps.
I'd appreciate any ideas or pointers.
Thank you kindly,
Matthias
Audio
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Hi everyone,
I’m working on an iOS MusicKit app that overlays a metronome on top of Apple Music playback. To line the clicks up perfectly I’d like access to low-level audio analysis data—ideally a waveform / spectrogram or beat grid—while the track is playing.
I’ve noticed that several approved DJ apps (e.g. djay, Serato, rekordbox) can already:
• Display detailed scrolling waveforms of Apple Music songs
• Scratch, loop or time-stretch those tracks in real time
That implies they receive decoded PCM frames or at least high-resolution analysis data from Apple Music under a special entitlement.
My questions:
1. Does MusicKit (or any public framework) expose real-time audio buffers, FFT bins, or beat markers for streaming Apple Music content?
2. If not, is there an Apple program or entitlement that developers can apply for—similar to the “DJ with Apple Music” initiative—to gain that deeper access?
3. Where can I find official documentation or a point of contact for this kind of request?
I’ve searched the docs and forums but only see standard MusicKit playback APIs, which don’t appear to expose raw audio for DRM-protected songs. Any guidance, links or insider tips on the proper application process would be hugely appreciated!
Thanks in advance.
I am using an AVAudioPlayer to play a "tick" sound once per second in a SwiftUI app.
When running the app on an iPhone 16 (18.2.1) the tick sounds increase in volume after a few seconds. This does not happen in the simulator nor on an iPhone SE 2020 (18.1.1).
Topic:
Media Technologies
SubTopic:
Audio
I've got a web app built with MusicKit that displays a list of songs.
I have player controls for play, pause, skip next, skip, previous, toggle shuffle and set repeat mode.
All of these work by using music.
The play button, when nothing is playing and nothing is in the queue, will enqueue all the tracks and start playing with the below, for example:
await music.setQueue({ songs, startPlaying: true });
I've implemented a progress slider based on feedback from the "playbackProgressDidChange" listener.
Now, how in the world can I set the volume? This seems like it should be simple, but I am at a complete loss here.
The docs say:
"The volume of audio playback, which is set directly on the HTMLMediaElement as the HTMLMediaElement.volume property. This value ranges between 0, which would be muting the audio, and 1, which would be the loudest possible."
Given that all my controls work off the music instance, I don't understand how I can do that.
In this video from WWDC 2022, music web components are touched on briefly. These are also documented very sparsely. The volume docs are here.
For the life of me, I can't even get the volume web component to display in the UI.
It appears that MusicKit Web is hobbled compared to the native implementation, but surely adjusting volume shouldn't be that hard right?
I'd appreciate any insight on how to do this, including how to get web components to work (in a Next JS app).
Thanks.
I'm developing the VisionOS app. I want to know how to play spatial audio in addition to RealityKit? If it's iOS or macOS, how to play spatial audio in addition to RealityKit?
I have some tried-and-tested code that records and plays back audio via AUHAL which breaks on Tahoe on Intel. The same code works fine on Sequioa and also works on Tahoe on Apple Silicon.
To start with something simple, the following code to request access to the Microphone doesn't work as it should:
bool RequestMicrophoneAccess ()
{
__block AVAuthorizationStatus status =
[AVCaptureDevice authorizationStatusForMediaType: AVMediaTypeAudio];
if (status == AVAuthorizationStatusAuthorized)
return true;
__block bool done = false;
[AVCaptureDevice requestAccessForMediaType: AVMediaTypeAudio completionHandler: ^ (BOOL granted)
{
status = (granted) ? AVAuthorizationStatusAuthorized : AVAuthorizationStatusDenied;
done = true;
}];
while (!done)
CFRunLoopRunInMode (kCFRunLoopDefaultMode, 2.0, true);
return status == AVAuthorizationStatusAuthorized;
}
On Tahoe on Intel, the code runs to completion but granted is always returned as NO. Tellingly, the popup to ask the user to grant microphone access is never displayed, even though the app is not present in the Privacy pane and never appears there. On Apple Silicon, everything works fine.
There are some other problems, but I'm hoping they have a common underlying cause and that the Apple guys can figure out what's wrong from the information in this post. I'd be happy to test any potential fix. Thanks.
Topic:
Media Technologies
SubTopic:
Audio
Issue:
Under certain conditions, using CallKit does not automatically enable the microphone.
Steps to Reproduce:
1.Start an outgoing call, then the user manually mutes the audio.
2.Receive a native incoming call, end the current call, then answer the new incoming call.(This order is important.)
3.End the incoming call.
4.Start another outgoing call and observe the microphone; do not manually mute or unmute.
Actual Behavior:
The audio icon indicates that the audio is unmuted, but the microphone remains off, and the small yellow dot in the top status bar (which represents the microphone) does not appear.
Expected Behavior:
The microphone should be on, consistent with the audio icon display, and the small yellow dot should appear in the top status bar.
Device:
iPhone 16 pro & iPhone 15 pro, iOS 18.0+
Can it be reproduced using speakerbox(CallKit Demo)?
YES
Everytime I put my AirPods in and connect them to my phone or my Mac or my iPad since the iOS 18.3 update on my devices they’ve been disconnecting without reason, pausing songs I’m in the middle of playing, and only partially reconnecting in one pod and it’s getting really frustrating
Topic:
Media Technologies
SubTopic:
Audio
Hi everyone,
I’m working on an iOS MusicKit app that overlays a metronome on top of Apple Music playback, using ApplicationMusicPlayer. To line the clicks up perfectly I’d like access to low-level audio analysis data—ideally a waveform / spectrogram or beat grid—while the track is playing.
I’ve noticed that several approved DJ apps (e.g. djay, Serato, rekordbox) can already:
• Display detailed scrolling waveforms of Apple Music songs
• Scratch, loop or time-stretch those tracks in real time
That implies they receive decoded PCM frames or at least high-resolution analysis data from Apple Music under a special entitlement.
My questions:
Does MusicKit (or any public framework) expose real-time audio buffers, FFT bins, or beat markers for streaming Apple Music content?
If not, is there an Apple program or entitlement that developers can apply for—similar to the “DJ with Apple Music” initiative—to gain that deeper access?
Where can I find official documentation or a point of contact for this kind of request?
I’ve searched the docs and forums but only see standard MusicKit playback APIs, which don’t appear to expose raw audio for DRM-protected songs. Any guidance, links or insider tips on the proper application process would be hugely appreciated!
Thanks in advance.
It's only occurs on iOS 18+. Backtrace attached below.
Exception Codes: 0x0000000000000000, 0x0000000000000000
Termination Reason: SIGNAL 6 Abort trap: 6
Terminating Process: NoteKeys [24384]
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x1a2d4c7cc __exceptionPreprocess + 164 (NSException.m:249)
1 libobjc.A.dylib 0x1a001f2e4 objc_exception_throw + 88 (objc-exception.mm:356)
2 CoreFoundation 0x1a2e47748 +[NSException raise:format:] + 128 (NSException.m:0)
3 AVFAudio 0x1bd41f4c8 -[AVMIDIPlayer play:] + 300 (AVMIDIPlayer.mm:145)
4 NoteKeys 0x1023c0670 SoundGenerator.playData() + 20 (SoundGenerator.swift:170)
5 NoteKeys 0x1023c0670 EditViewController.playBtnTapped(startIndex:) + 940 (EditViewController.swift:2034)
6 NoteKeys 0x1024497fc specialized Keyboard.playBtnTapped(sender:) + 1904 (Keyboard.swift:1249)
7 NoteKeys 0x10244631c Keyboard.playBtnTapped(sender:) + 4 (<compiler-generated>:0)
8 NoteKeys 0x10244631c @objc Keyboard.playBtnTapped(sender:) + 48
9 UIKitCore 0x1a58739cc -[UIApplication sendAction:to:from:forEvent:] + 100 (UIApplication.m:5816)
10 UIKitCore 0x1a58738a4 -[UIControl sendAction:to:forEvent:] + 112 (UIControl.m:942)
11 UIKitCore 0x1a58736f4 -[UIControl _sendActionsForEvents:withEvent:] + 324 (UIControl.m:1013)
12 UIKitCore 0x1a5fe8d8c -[UIButton _sendActionsForEvents:withEvent:] + 124 (UIButton.m:4198)
13 UIKitCore 0x1a5fea5a0 -[UIControl touchesEnded:withEvent:] + 400 (UIControl.m:692)
14 UIKitCore 0x1a57bb9ac -[UIWindow _sendTouchesForEvent:] + 852 (UIWindow.m:3318)
15 UIKitCore 0x1a57bb3d8 -[UIWindow sendEvent:] + 2964 (UIWindow.m:3641)
16 UIKitCore 0x1a564fb70 -[UIApplication sendEvent:] + 376 (UIApplication.m:12972)
17 UIKitCore 0x1a565009c __dispatchPreprocessedEventFromEventQueue + 1048 (UIEventDispatcher.m:2686)
18 UIKitCore 0x1a5659f3c __processEventQueue + 5696 (UIEventDispatcher.m:3044)
19 UIKitCore 0x1a5552c60 updateCycleEntry + 160 (UIEventDispatcher.m:133)
20 UIKitCore 0x1a55509d8 _UIUpdateSequenceRun + 84 (_UIUpdateSequence.mm:136)
21 UIKitCore 0x1a5550628 schedulerStepScheduledMainSection + 172 (_UIUpdateScheduler.m:1171)
22 UIKitCore 0x1a555159c runloopSourceCallback + 92 (_UIUpdateScheduler.m:1334)
23 CoreFoundation 0x1a2d20328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28 (CFRunLoop.c:1970)
24 CoreFoundation 0x1a2d202bc __CFRunLoopDoSource0 + 176 (CFRunLoop.c:2014)
25 CoreFoundation 0x1a2d1ddc0 __CFRunLoopDoSources0 + 244 (CFRunLoop.c:2051)
26 CoreFoundation 0x1a2d1cfbc __CFRunLoopRun + 840 (CFRunLoop.c:2969)
27 CoreFoundation 0x1a2d1c830 CFRunLoopRunSpecific + 588 (CFRunLoop.c:3434)
28 GraphicsServices 0x1eecfc1c4 GSEventRunModal + 164 (GSEvent.c:2196)
29 UIKitCore 0x1a5882eb0 -[UIApplication _run] + 816 (UIApplication.m:3844)
30 UIKitCore 0x1a59315b4 UIApplicationMain + 340 (UIApplication.m:5496)
31 NoteKeys 0x10254bc10 main + 68 (AppDelegate.swift:15)
32 dyld 0x1c870aec8 start + 2724 (dyldMain.cpp:1334)
Thanks very much for any help: )
Topic:
Media Technologies
SubTopic:
Audio
I have tried everything. The songs load unto the playlists and on searches, but when prompted to play, they just won't play.
I have a wrapper since my main player (which carries the buttons for play/rewind/forward/etc.), is in Objc.
//
// ApplePlayerWrapper.swift
// UniversallyMac
//
// Created by Dorian Mattar on 11/10/24.
//
import Foundation
import MusicKit
import MediaPlayer
@objc public class MusicKitWrapper: NSObject {
@objc public static let shared = MusicKitWrapper()
private let player = ApplicationMusicPlayer.shared
// Play the current track
@objc public func play() {
guard !player.queue.entries.isEmpty else {
print("Queue is empty. Cannot start playback.")
return
}
logPlayerState(message: "Before play")
Task {
do {
try await player.prepareToPlay()
try await player.play()
print("Playback started successfully.")
} catch {
if let nsError = error as NSError? {
print("NSError Code: \(nsError.code), Domain: \(nsError.domain)")
}
}
logPlayerState(message: "After play")
}
}
// Log the current player state
@objc public func logPlayerState(message: String = "") {
print("Player State - \(message):")
print("Playback Status: \(player.state.playbackStatus)")
print("Queue Count: \(player.queue.entries.count)")
// Only log current track details if the player is playing
if player.state.playbackStatus == .playing {
if let currentEntry = player.queue.currentEntry {
print("Current Track: \(currentEntry.title)")
print("Current Position: \(player.playbackTime) seconds")
print("Track Length: \(currentEntry.endTime ?? 0.0) seconds")
} else {
print("No current track.")
}
} else {
print("No track is playing.")
}
print("----------")
}
// Debug the queue
@objc public func debugQueue() {
print("Debugging Queue:")
for (index, entry) in player.queue.entries.enumerated() {
print("\(index): \(entry.title)")
}
}
// Ensure track availability in the queue
public func queueTracks(_ tracks: [Track]) {
Task {
do {
for track in tracks {
// Validate Play Parameters
guard let playParameters = track.playParameters else {
print("Track \(track.title) has no Play Parameters.")
continue
}
// Log the Play Parameters
print("Track Title: \(track.title)")
print("Play Parameters: \(playParameters)")
print("Raw Values: \(track.id.rawValue)")
// Ensure the ID is valid
if track.id.rawValue.isEmpty {
print("Track \(track.title) has an invalid or empty ID in Play Parameters.")
continue
}
// Queue the track
try await player.queue.insert(track, position: .afterCurrentEntry)
print("Queued track: \(track.title)")
}
print("Tracks successfully added to the queue.")
} catch {
print("Error queuing tracks: \(error)")
}
debugQueue()
}
}
// Clear the current queue
@objc public func resetMusicPlayer() {
Task {
player.stop()
player.queue.entries.removeAll()
print("Queue cleared.")
print("Apple Music player reset successfully.")
}
}
}
I opened an Apple Dev. ticket, but I'm trying here as well. Thanks!
Hello,
Has anyone else experienced variations in the accuracy of the playbackTime value? After a few seconds of playback, the reported time adjusts by a fraction of a second, making it difficult to calculate the actual playbackTime of the audio.
This can be recreated by playing a song in MusicKit, recording the start time of the audio, playing for at least 10-20 seconds, and then comparing the playbackTime value to one calculated using the start time of the audio. In my experience this jump occurs after about 10 seconds of playback.
Any help would be appreciated.
Thanks!
I recently installed a rear-view camera in my car, and ever since, I've been experiencing a frustrating issue with my CarPlay. After about 15 seconds of playing audio via Bluetooth, the sound stops coming out of the speakers, even though the song continues to run in the background.
For context, my stereo system is an aftermarket unit that I installed to enable CarPlay functionality. Everything worked perfectly before adding the rear-view camera. Unfortunately, my unit does not have a port for a wired connection, so I can't test the audio using a cable.
Has anyone experienced a similar issue? Could the camera installation be interfering with the Bluetooth or audio system somehow? Any advice or troubleshooting tips would be greatly appreciated!
Hello! I'm use AVFoundation for preview video and audio from selected device, and I try use AVAudioEngine for preview audio in real-time, but I can't or I don't understand how select input device? I can hear only my microphone in real-time
So far, I'm using AVCaptureAudioPreviewOutput for in real-time hear audio, but I think has delay.
On iOS works easy with AVAudioEngine, but on macOS bruh...
Topic:
Media Technologies
SubTopic:
Audio
Tags:
AudioToolbox
AVAudioSession
AVAudioEngine
AVFoundation
I have an app that records a health provider’s conversation with a patient. I am using Audio Queue Services for this. If a phone call comes in while recording, the doctor wants to be able to ignore the call and continue the conversation without touching the phone. If the doctor answers the call, that’s fine – I will stop the recording. I can detect when the call comes in and ends using CXCallObserver and AVAudioSession.interruptionNotification. Unfortunately, when a call comes in and before it is answered or dismissed, the audio is suppressed. After the call is dismissed, the audio continues to be suppressed. How can I continue to get audio from the mic as long as the user does not answer the phone call?
Topic:
Media Technologies
SubTopic:
Audio
I'm working in Swift/SwiftUI, running XCode 16.3 on macOS 15.4 and I've seen this when running in the iOS simulator and in a macOS app run from XCode. I've also seen this behaviour with 3 different audio files.
Nothing in the documentation says that the speechRecognitionMetadata property on an SFSpeechRecognitionResult will be nil until isFinal, but that's the behaviour I'm seeing.
I've stripped my class down to the following:
private var isAuthed = false
// I call this in a .task {} in my SwiftUI View
public func requestSpeechRecognizerPermission() {
SFSpeechRecognizer.requestAuthorization { authStatus in
Task {
self.isAuthed = authStatus == .authorized
}
}
}
public func transcribe(from url: URL) {
guard isAuthed else { return }
let locale = Locale(identifier: "en-US")
let recognizer = SFSpeechRecognizer(locale: locale)
let recognitionRequest = SFSpeechURLRecognitionRequest(url: url)
// the behaviour occurs whether I set this to true or not, I recently set
// it to true to see if it made a difference
recognizer?.supportsOnDeviceRecognition = true
recognitionRequest.shouldReportPartialResults = true
recognitionRequest.addsPunctuation = true
recognizer?.recognitionTask(with: recognitionRequest) { (result, error) in
guard result != nil else { return }
if result!.isFinal {
//speechRecognitionMetadata is not nil
} else {
//speechRecognitionMetadata is nil
}
}
}
}
Further, and this isn't documented either, the SFTranscriptionSegment values don't have correct timestamp and duration values until isFinal. The values aren't all zero, but they don't align with the timing in the audio and they change to accurate values when isFinal is true.
The transcription otherwise "works", in that I get transcription text before isFinal and if I wait for isFinal the segments are correct and speechRecognitionMetadata is filled with values.
The context here is I'm trying to generate a transcription that I can then highlight the spoken sections of as audio plays and I'm thinking I must be just trying to use the Speech framework in a way it does not work. I got my concept working if I pre-process the audio (i.e. run it through until isFinal and save the results I need to json), but being able to do even a rougher version of it 'on the fly' - which requires segments to have the right timestamp/duration before isFinal - is perhaps impossible?
iPhoneやiPadにおいて、画面上のボタンなどをタップした際に、特定の楽器音を発音させる方法をご存知の方いらっしゃいませんか?
現在音楽学習アプリを作成途中で、画面上の鍵盤や指板のボタン状のframeに、単音又は和音を割当て発音させる事を考えております
SwiftUIのcodeのみで実現できないでしょうか
嘗て、MIDIのlevel1の楽器の発音機能があった様に記憶していますが、現在のOS上では同様の機能を実装してないように思えます
皆様のお知恵をお貸しください
After investing more than a week into getting a bunch of audio unit projects converted into app + appex + framework, they all are now correctly loaded in-process in the demo host app that is part of Xcode's template.
However, Logic Pro adamantly refuses to load them in-process.
Does Logic Pro simply not do that ever, or is there some hint or configuration my plugins need to provide to enable that? If it is unsupported, will it be supported in some future version of Logic?
The entire point of investing that week was performance, which is moot if it is impossible to test the impact of loading in-process in a real-world usage scenario.
Mobile app - Ellie's Gift
https://apps.apple.com/gb/app/ellies-gift/id1617597875
Using AVFoundation to play audio tracks within the app.
Has always been working fine across apple and android, but iphone 14 and newer devices are unable to play audio.
Any idea's or suggestions?
Hi,
On macOS I used to open MP3 and MP4 files with ExtAudioFile. For a few years it doesn't work anymore.
So I decided to try different macOS API using the AudioFileID of AudioToolbox framework.
I decided to write a test:
https://gist.github.com/joelkraehemann/7f5b241b52ca38c3a765c138fb647588
It fails right here:
AudioFileOpenWithCallbacks()
By telling OSStatus error 1954115647, which means kAudioFileUnsupportedFileTypeError.
The filename was set to an MP4 file:
~/Music/test.mp4
Howto fix this?
regards, Joël