We are facing a strange issue where a small portion of our large userbase can not start the capture session in our app, as it gets interrupted with the following reason:
AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps
Our users are all from iPhones, no one is using an iPad. Just to be sure we have set
session.isMultitaskingCameraAccessEnabled = true
but it does not seem to make any difference.
Another weird interruption we are seeing
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I have an AUv3 that passes all validation and can be loaded into Logic Pro without issue. The UI for the plug in can be any aspect ratio but Logic insists on presenting it in a view with a fixed aspect ratio. That is when resizing, both the height and width are resized. I have never managed to work out what it is I need to do specify to Logic to allow the user to resize width or height independently of each other.
Can anyone tell me what I need to specify in the AU code that will inform Logic that the view can be resized from any side of the window/panel?
Hi,
Could anybody share the full list of supported Predicate keys for the PHFetchOptions?
I'm aware of the list that is posted in the documentation:
https://developer.apple.com/documentation/photos/phfetchoptions
However I have reason to believe that this is not an exhaustive list and there also seem to be mistakes in this doc. i.e. isFavorite does not work but favorite does.
Through some experimentation I also found that this works:
NSPredicate(format: "adjustmentFormatIdentifier == 'com.pixelmatorteam.touch.x.photo.PhotosAdjustmentData.EmbeddedSlimSidecarFileInfo.compressed'")
even though adjustmentFormatIdentifier is not listed as a supported key.
Are there other secret keys that you are aware of?
Specifically I want to filter a fetch result for edited items. Something like this:
NSPredicate(format: "hasAdjustments == true")
(I tried this, doesn't work)
The native Photos app has such a filter which leads me to believe that there probably is a key for this:
If one of the Framework Developers reads this: Could you please update the documentation page with this information?
Finally if there really aren't any more secret keys, is there a way to achieve this with adjustmentFormatIdentifier? I have tried a bunch of stuff already like adjustmentFormatIdentifier != nil but for some reason that gives me the exact opposite of what I want: all the photos without edits. 🫠
Any tips on the correct syntax here would be much appreciated.
Feature Request: Long-Lived Access to Personal Apple Music Data
Use Case Summary
I'm developing a personal portfolio website (using Nuxt) and want to display information from my own Apple Music library - showcasing personal playlists, recently played tracks, or a read-only "now playing" widget. This is purely for personal use on my website and doesn't require other users to log in.
With Spotify's API, implementing this was straightforward thanks to automatic token refresh. I want a similarly seamless integration with Apple Music.
Challenge with MusicKit and Music User Tokens
Apple Music API requirements
Apple's Music API requires a valid Music User Token (MUT) for requests involving personal library data. Beyond the Apple Developer Token, you must obtain a user-specific token via MusicKit authentication to access your own library playlists, play history, or current playback status.
Token expiration and manual renewal
Music User Tokens expire after approximately 6 months without any mechanism to automatically refresh or renew them - unlike typical OAuth flows that provide refresh tokens. Apple's guidance suggests the device (e.g., iPhone) is responsible for obtaining new user tokens when old ones expire. This works for interactive apps on Apple devices but fails in server-side or long-lived web contexts like a personal website widget.
Impact on personal projects
Displaying Apple Music data on a public-facing site becomes difficult. I would need to periodically re-authenticate through the MusicKit JS flow every few months just to keep a widget alive. Embedding credentials in a public site is insecure, and manual token refreshing is cumbersome and easy to forget.
Comparison to Spotify's Token Model
Spotify's API offers a developer-friendly authentication model. Their OAuth flow provides a Refresh Token that applications can use to obtain new access tokens automatically without requiring user re-authorization. This means a personal app can maintain continuous access to a user's Spotify data for extended periods until access is revoked.
When building a similar feature with Spotify, this automatic token renewal was crucial. I could safely store the refresh token on my server and have my app periodically update the access token. Many developers have created public-facing widgets showing currently playing tracks on blogs or GitHub profiles using this model. Unfortunately, Apple Music's API lacks an equivalent capability, putting it at a disadvantage for personal projects.
Proposed Solutions
I request Apple's consideration for one of these enhancements:
Provide a mechanism to refresh or extend a Music User Token programmatically for server-side applications. This could be an OAuth-style refresh token issued alongside the MUT, or a dedicated endpoint to exchange an expired MUT for a new one. This would enable renewal without a full user re-auth/login each time.
Allow developers to access their own Apple Music library data with just the long-lived Developer Token. Apple could permit GET requests to personal library endpoints using the Developer Token alone, or a special token tied to the developer's Apple ID. This access would be read-only - no ability to modify the library, purely for retrieving data. It could be an opt-in feature in the Apple Developer account settings.
Either solution would significantly improve the developer experience for Apple Music API in personal projects.
Security and Privacy Considerations
This request is not about accessing others' data or creating privacy loopholes - it's about empowering an Apple Music subscriber to access their own information more conveniently. The proposed options respect privacy principles:
The data accessed is only what the user already has access to - their own playlists, library items, or playback status.
An automatic token refresh can be designed securely (revocable tokens bound to a single account with no increase in permissions).
Read-only developer token access could be restricted to non-sensitive data and require explicit opt-in.
Conclusion
I request an improvement to Apple Music's developer experience through either (1) an automatic Music User Token refresh mechanism, or (2) a provision for read-only personal library access using a Developer Token. This would bring Apple Music integration capabilities closer to parity with services like Spotify for personal projects.
I ask Apple's Developer Relations and the Apple Music API team to consider this feature request. If there are existing best practices or workarounds with current APIs, I would appreciate guidance.
I invite feedback from Apple or other developers. Are there known patterns for maintaining an Apple Music user token for server-side applications, or any plans to support non-interactive use cases? Any advice is welcome.
Thank you for your consideration. I look forward to integrating Apple Music into my personal site as smoothly as with other services, and believe many developers would benefit from this added flexibility.
Sources:
User Authentication for MusicKit - Requirements for Music User Tokens
StackOverflow: Do Apple Music User Tokens expire? - Confirmation of 6-month expiration
MetaBrainz GSoC Blog - Documentation of MusicKit authentication limitations
Apple Developer Forums - Information on token renewal behavior
Spotify for Developers - Documentation on refresh token mechanism
Topic:
Media Technologies
SubTopic:
Audio
Tags:
Apple Music API
MusicKit
MusicKit JS
Apple Music Feed
I'm capturing video stream from GoPro camera (via UDP MPEG-TS packets) but unable to play in iOS app. can someone provide a source code to decode MPEG-TS data to CMSampleBuffer.
When trying to edit some Live Photos, calling PHLivePhotoEditingContext.saveLivePhoto results in the following error:
Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSLocalizedFailureReason=An unknown error occurred (-12815), NSLocalizedDescription=The operation could not be completed, NSUnderlyingError=0x300d05380 {Error Domain=NSOSStatusErrorDomain Code=-12815 "(null)"}}
I was able to replicate it on my device by taking a new Live Photo. Not sure what's wrong with that one specifically, not all Live Photos replicate the issue.
I've submitted FB15880825 with a sysdiagnose and a Photos Diagnostics as well. Any ideas what's going on here? It's impacting multiple customers. Thanks!
Topic:
Media Technologies
SubTopic:
Photos & Camera
Tags:
Media
Photos and Imaging
PhotoKit
AVFoundation
I’m building a music app using Apple Music streaming via ApplicationMusicPlayer.
My goal is to decrease the volume of the current song during the last 10 seconds, and when the next track begins, restore the volume to its normal level.
I know that ApplicationMusicPlayer doesn’t expose a volume API, and I want to avoid triggering the system volume HUD.
✅ Using Apple Music streaming (not local files)
❓ Is it possible to implement per-track fade-out/fade-in logic with ApplicationMusicPlayer?
Appreciate any clarification or official guidance!
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?
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!}
Dear Apple Developer Community,
I'm encountering a critical issue with the MusicLibrary.shared.createPlaylist() method in MusicKit that's affecting our app's core functionality. Despite implementing all recommended authorization checks, the app consistently freezes for some users when this method is called.
What we've already verified before calling createPlaylist():
Network connectivity is properly checked and confirmed
Apple Music authorization is explicitly requested via MusicAuthorization.request()
User subscription status is verified using MusicSubscription.current.canPlayCatalogContent
Despite these precautions, many users report that their app completely freezes when attempting to create a playlist. This is particularly concerning as playlist creation is a core feature of our application.
User-reported workarounds (with mixed success):
Some users have resolved the issue by restarting their devices or reinstalling our app
Others report success after enabling "Sync Library" in Settings → Music Unfortunately, a significant number of users are still experiencing the issue even after trying both solutions above
We've reviewed the MusicKit documentation thoroughly and ensured our implementation follows all best practices. Our app correctly handles permissions and uses the async/await pattern as required by the API.
Is there a known issue with the createPlaylist() method that might cause it to block indefinitely? Are there additional authorization steps or settings we should be checking before calling this method? Could this be related to how MusicKit communicates with Apple Music servers?
Any insights from the developer community or official guidance would be greatly appreciated as this issue is severely impacting our user experience.
Thank you for your assistance
I'm seeking to a specific sync frame in a video file (HEVC, recorded on iPad). When I feed the buffers from that sync frame on to VTDecompressionSession it consistently drops the 2.,3.,4. buffer with a kVTVideoDecoderReferenceMissingErr (or no error but no buffer on the simulator). If I feed all the buffers from the penultimate sync frame prior to the desired frame the buffers come out fine but that would just create a massive overhead to always do it. Tried multiple OS versions, devices etc. Seems a consistent problem.
Here's a sample project with the offending video (disregard memory handling etc):
https://github.com/marcuseckert/vtSample
I've filed a radar FB18228296 but would appreciate any feedback on circumventing or at least detecting this behavior prior to decoding.
Short summary
When setting exposureMode to .locked or .custom the brightness of a video stream still changes depending on the composition and contrast of the visible scene. These changes seem to come from contrast enhancements or dynamic range optimizations and totally break any analysis of the image that requires to assess absolute luminance. While exposure lock seems to indeed lock the physical exposure parameters of the camera (shutter speed and ISO), I cannot find any way to control these "soft" modifiers.
Details
Background
I am the developer of the app "phyphox", an educational app that makes the phone's sensors accessible to students as measurement tools in science experiments. Currently I am working on implementing photometric measurements through the camera and one very important aspect of it is luminance measurements.
This is particularly relevant since the light sensor of the phone has no publicly accessible API and the camera could to some extend make experiments available to Apple users that are otherwise only possible on Android devices.
Implementation
The app uses AVFoundation and explicitly picks individual cameras since camera groups do not support custom exposure settings. This means that it handles camera switching during zoom by itself and even implements its own auto exposure routines to optimize for the use in experiments. Therefore it always stays in custom exposure mode. The app uses YUV420 color space and the individual frames are analyzed in Metal using compute shaders.
However, the effects discussed here still occur if I remove all code to control the camera and replace it with a simple sequence of setting the exposure mode to custom, setting custom exposure values, setting a fixed white balance and then setting the exposure mode to locked as suggested on stackoverflow. This neither helps on an iPhone 14 Pro nor on an iPhone 8 despite a report on the developer forums that it would resolve the issue for older devices.
The app is open source, so the code can be seen in our current development branch (without the changes for the tests here, though) on github.
The videos below use the implementation with the suggestion from stackoverflow, but they can be reproduced in the same way with "professional" camera apps that promise manual control over the camera (like the Blackmagic cam to quote a reputable company) as well as the stock camera app after pressing and holding on the preview to enable AE/AF lock.
Demonstration
These examples were captured on an iPhone 14 Pro. The central part of the image (highlighted by the app using metal shaders after capture) should not change with fixed exposure settings, but significant changes are noticable if there are changes at the edge of the frame when I move a black piece of cardboard in from above:
https://share.icloud.com/photos/0b1f_3IB6yAQG-qSH27pm6oDQ
The graph above the camera preview is the average luminance (gamma corrected and weighted based on sRGB) across the highlighted central area and as mentioned before it should not change because of something happening at the side of the frame (worst case it should get a bit darker because of the cardboard's shadow).
In my opinion, the iPhone changes its mind on the ideal contrast as soon as it has a different exposure histogram because of the dark image part from the cardboard, but that's just me guessing.
For completeness here is the same effect in the stock camera app with AE/AF lock enabled:
https://share.icloud.com/photos/0cd7QM8ucBZKwPwE9mybnEowg
Here you can also see that the iPhone "ramps" the changes. The brightness of the gray area does not change immediately but transitions smoothly, so this is clearly deliberate postprocessing.
So...
Any suggestion on how to prevent this behavior would be highly appreciated.
We are seeing logs were on iOS devices we see some keyframes request.
but on safari browser don’t see any request like this. could you please explain what is it.
/d8ceb9244ff889b42b82eb807327531-c27dbcb10e0bbf3cde6c-1/d8ceb9244ff88e9b42b82eb807327531-c27dbcb10e0bbf3cde6c-1/keyframes/hls/.
I’m developing a hybrid app (WebView / Turbo Native) that uses getUserMedia to access the back camera for a PPG/heart rate measurement feature (the user places their finger on the camera).
Problem: Even when I specify constraints like:
{
video: {
deviceId: '...',
facingMode: { exact: 'environment' },
advanced: [{ zoom: 1.0 }]
},
audio: false
}
On iPhone 15 (iOS 18), iOS unexpectedly switches between the wide, ultra-wide, and telephoto lenses during the measurement.
This breaks the heart rate detection, and it forces the user to move their finger in the middle of the measurement.
Question: Is there any way, via getUserMedia/WebRTC, to force iOS to use only the wide-angle lens and prevent automatic lens switching?
I know that with AVFoundation (Swift) you can pick .builtInWideAngleCamera, but I’m hoping to avoid building a custom native layer and would prefer to stick with WebView/JavaScript if possible to save time and complexity.
Any suggestions, workarounds, or updates from Apple would be greatly appreciated!
Thanks a lot!
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!
Hi there!
We have a suite of AudioUnit v2 plugins that have been shipped for some time as aufx plugins, and we are looking into MIDI-related platform upgrades, so we need a way to update these plugins to request MIDI from Logic (and other AU hosts) but avoid changing our AU type and subtype so we don't break existing sessions. Any ideas on how we can do this?
I developed a driverkit extension based on overriding-the-default-usb-video-class-extension, but the link didn’t give the details of realization. I asked DTS who gave two tips:
1, Do you also have a CMIO extension to load in place of the default overriding-the-default-usb-video-class-extension
2, Your DriverKit extension’s info.plist is also missing the CameraAssistantBundleID.
I want to know why a driverkit extension needs a CMIO extension, what’s the data and control flow?
I have a music app I'm developing and having a weird issue where I can see now playing info for every other platform than tvOS. As far as I can tell I have correctly configured the MPNowPlayingInfoCenter
MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo MPNowPlayingInfoCenter.default().playbackState = .playing
Are there any extra requirements to get my app's now-playing info showing in control center on tvOS? Another strange issue that might be related is I can use the apple TV remote to pause audio but not resume playback, so I feel like there's something I'm missing about registering audio playback on tvOS specifically.
i have a wallpaper app , i need a photos access when i try to add it in capabilities i don't find it.is there any solution?
Hello everyone,
I am working on an app that allows you to review your own music using Apple Music. Currently I am running into an issue with the skipping forwards and backwards outside of the app.
How it should work: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song on an album should play and the information should change to reflect that in the app.
If you play a song in Apple Music, you can see a Now Playing view in the lock screen.
When you skip forward or backwards, it will do either action and it would reflect that when you see a little frequency icon on artwork image of a song.
What it's doing: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song is reflected outside of the app, but not in the app.
When skipping a song outside of the app, it works correctly to head to the next song.
But when I return to the app, it is not reflected
NOTE: I am not using MusicKit variables such as Track, Album to display the songs. Since I want to grab the songs and review them I need a rating so I created my own that grabs the MusicItemID, name, artist(s), etc.
NOTE: I am using ApplicationMusicPlayer.shared
Is there a way to get the song to reflect in my app?
(If its easier, a simple example of it would be nice. No need to create an entire xprod file)