I am developing an iOS app that needs to play spoken audio on demand from a server, while ducking the audio of background music from another app (e.g., SoundtrackYourBrand or Apple Music). This must work even when the app is in the background, and the server dictates when and what audio is played. Ideally, the message should be played within a minute of the server requesting it.
Current Attempt & Observations
I initially tried using Firebase Cloud Messaging (FCM) silent notifications to send a URL to an audio file, which the app would then play using AVPlayer.
This works consistently when the app is active, but in the background, it only works about 60% of the time.
In cases where it fails, iOS ducks the background music (e.g., from SoundtrackYourBrand) but never plays the spoken audio.
Interestingly, when I play the audio without enabling audio ducking, it seems to work 100% of the time from my limited testing, even in the background.
The app has background modes enabled for Audio, Background Fetch, and Remote Notifications.
Best Approach to Achieve This?
I’d like guidance on the best Apple-compliant approach to reliably play audio on command from the server, even when the app is in the background. Some possible paths:
Ensuring the app remains active in the background – Are there recommended ways to prevent the app from getting suspended, such as background tasks, a special background mode, or a persistent connection to the server?
Alternative triggering mechanisms – Would something like VoIP, Push-to-Talk, or another background service be better suited for this use case?
Built-in iOS speech synthesis (AVSpeechSynthesizer) – If playing external audio is unreliable, would generating speech dynamically from text be a more robust approach?
Streaming audio instead of sending a URL – Could continuous streaming from the server keep the app active and allow playback at the right moment?
I want to ensure the solution is reliable and works 100% of the time when needed. Any recommendations on the best approach for this would be greatly appreciated.
Thank you for your time and guidance.
Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
Hello,
Our users have started to see a new fatal AVPlayer error during playback starting with iOS/tvOS 18.0. The error is defined as "CoreMediaErrorDomain Code=-15486".
We have not been able to reproduce this issue locally within our development team.
Is there any documentation on the cause of this error or steps to recover from this error?
Thank you,
Howard
Topic:
Media Technologies
SubTopic:
Streaming
Tags:
FairPlay Streaming
HTTP Live Streaming
AVFoundation
I've been having issues with authorization after switching from v1 to v3, have tried some of the suggestions provided by someone in a reply to a post of mine. Have tried to reach out to Apple Support a few times as well, though I haven't received any support that has helped me to move forward.
I have tested my token at https://jwt.io and I'm getting a "Signature Verified", tried multiple browsers in private/incognito mode, now when I try to sign into my Apple Account to test my player I am receiving an error that stats "There is a Problem Connecting. There May be an Issue with Your Network." (which is not the case).
I have tried everything I can think of, I'm at a loss and would appreciate any help to get my project moving forward. This is what I am seeing in the browser developer console (using Firefox):
Authorization failed: AUTHORIZATION_ERROR: Unauthorized
MKError https://js-cdn.music.apple.com/musickit/v3/musickit.js:13
authorize https://js-cdn.music.apple.com/musickit/v3/musickit.js:28
asyncGeneratorStep$w https://js-cdn.music.apple.com/musickit/v3/musickit.js:28
_next https://js-cdn.music.apple.com/musickit/v3/musickit.js:28
media.mydomain.com:398:19
https://media.mydomain.com/:398
I’m working on a macOS app, written in Swift. My goal is to record audio from an external microphone, e.g., one connected via USB.
For this, I’m using an AVCaptureSession and recording its output with an AVAssetWriter. This works perfectly in principle (and reliably with internal microphones, for example).
The problem occurs after my app has successfully completed the first recording and I then want to make additional recordings (which makes me think it might be process-dependent, because it works again after restarting the app).
The problem: Noisy or distorted-sounding audio files. In addition, the following error message appears in the Console from CoreAudio / its AudioConverter:
Input data proc returned inconsistent 512 packets for 2048 bytes; at 3 bytes per packet, that is actually 682 packets
It is easy to reproduce. This problem is reproducible even if I don’t configure the AVAssetWriter manually and instead let it receive its audioSettings using a preset from an AVOutputSettingsAssistant. I’m running on macOS 15.0 (24A335).
I’ve filed a feedback including a demo project → FB15333298 🎟️
I would greatly appreciate any help!
Have a great day,
Martin
Hi,
I'm using Core Graphics to load a .DNG photo shot by a Leica Q3 camera.
The photo is shot in portrait, however the embedded preview is rotated 90 degrees to landscape.
I load the photo like this:
let options = [kCGImageSourceDecodeRequest: kCGImageSourceDecodeToHDR] as CFDictionary
let source = CGImageSourceCreateWithData(data as CFData, nil)
let cgimage = CGImageSourceCreateImageAtIndex(source, 0, options)
let properties = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as? [CFString : Any]
When doing this I can see that the orientation property is 1 indicating that the orientation is 'Up', which it isn't.
If I don't specify the kCGImageSourceDecodeToHDR option (eseentially setting options to nil) - the orientation property is 8 (rotated 90 degrees).
What puzzles me is that a chang to the CGImageSourceCreateImageAtIndex call can have an influence on that latter call to CGImageSourceCopyPropertiesAtIndex ?
I would expect these to work independently?
Cheers
Thomas
I am writing an iOS app to present a slide show of assets in a Photo album, in a random order, including videos and live photos. I have got it all working quite nicely but for a Live Photo, I need to know what effect is selected (Live, Loop, Bounce, Long Exposure, Live Off) to display the image correctly. I can't find any mention of getting this information in the documentation. Anyone know how to do this? Thanks in advance.
Adrian.
(Xcode 16.1 iOS 18.0)
Topic:
Media Technologies
SubTopic:
Photos & Camera
I can't play video content with HEVC and DRM. Tested HEVC only: OK. Tested DRM+AVC: Ok.
Tested 2 players (Clappr/Stevie and BitMovin)
Master, variants and EXT-X-MAPs are downloaded Ok, DRM keys Ok and then, for instance with BitMovin Player:
[BMP] [Player] [Error] Event: SourceError, Data: {"code":2001,"data":{"message":"The operation couldn’t be completed. (CoreMediaErrorDomain error -12927.)","code":-12927},"message":"Source Error. The operation couldn’t be completed. (CoreMediaErrorDomain error -12927.)","timestamp":1740320663.4505711,"type":"onSourceError"} code: 2001 [Data code: -12927, message: The operation couldn’t be completed. (CoreMediaErrorDomain error -12927.), underlying error: Error Domain=CoreMediaErrorDomain Code=-12927 "(null)"]
4k-master.m3u8.txt
4k.m3u8.txt
4k-audio.m3u8.txt
In MusicKit Web the playback states are provided as numbers.
For example the playbackStateDidChange event listener will return:
{oldState: 2, state: 3, item:...}
When the state changes from playing (2) to paused (3).
Those are pretty easy to guess, but I'm having a hard time with some of the others: completed,
ended,
loading,
none,
paused,
playing,
seeking,
stalled,
stopped,
waiting.
I cannot find a mapping of states to numbers documented anywhere. I got the above states from an enum in a d.ts file that is often incorrect/incomplete.
Can someone help out pointing to the docs or provide a mapping?
Thanks.
Hi,
Currently I am developing a 3D reconstruction project.
Which requires images to be distortion-free (rectilinear) and with known intrinsics.
The session I am developing on is a builtInDualWideCamera, with isGeometricDistortionCorrectionEnabled set to false to be able to get the intrinsic matrix of the images, isVirtualDeviceConstituentPhotoDeliveryEnabled set to true and isAutoVirtualDeviceFusionEnabled set to false to get both images and isCameraCalibrationDataDeliveryEnabled set to true to actually get the calibration data.
The distortion correction parameters such as lensDistortionLookupTable are used.
The 42 coefficients mapping array is used as described in the AVCameraCalibrationData header file. A simple piecewise linear interpolation.
There are two questions I would like to get support on:
A way to set the calibration parameters in each image.
I have an approach that sets the parameters in the kCGImagePropertyExifDictionary -> "UserComment". Is there a better approach to write calibration parameter data into the images? I feel like this is a bit dirty and there might be a better and neat approach.
For the ultra-wide angle camera's images, the lensDistortionLookupTable contains several zeros at the end of the array.
For example (last 10 elements are zero):
"LensDistortionLookupTable":"0.000000000000000,0.000349554029526,0.001385628827848,0.003071037586778,... ,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000"
The problem comes when the complete array is used to correct the image (including zeros), the end result is a wrapped-like-circle image close to the edges of it which is completely wrong.
In contrast, if the LensDistortionLookupTable is used without the last zeros and the new size accommodated the image looks better (although not as rectilinear as if you take the image from the iPhone's camera app), but definitely less distorted.
Including zeros (full array):
Excluding zeros (array size changed):
Am I missing an important point in the usage of the lensDistortionLookupTable where this case is addressed (zeros at the end)?
What is the criteria to shrink/exclude elements of the array?
Any advice is very much welcome.
Context
We develop an iOS/Apple TV app that allows to play HLS+FP Live streams (custom playback UI), some of which use the same FairPlay content key id. All FairPlay content keys are requested to the same content key server.
Implementation
Despite Apple documentation warning to not reuse AVContentKeySessions, we use only one AVContentKeySession for all channels which allows the system to reuse the content key when a content key id is met again. As seen in another thread, people seems to think this is OK.
Issue
When reusing the AVContentKeySession and the user quickly tunes channels multiple times (up to 2 or 3 times per second using gestures), an inconsistency may occur where the content key request for a previous streams is asked to the delegate after a new stream is already being prepared and its AVURLAsset already assigned as the content key session AVContentKeyRecipient. Note that the previous content key recipient is removed before the new one is added.
We also have been reported for crashes (though I haven't experienced it myself) when performing multiple channels tunings which makes us think that the AVContentKeySession should definitely not been reused.
Note: On the other hand if a new AVContentKeySession is used for each stream, the system systematically requests a content key even if previous streams have used the same content key id. In this case, neither the crash nor the inconsistency issue are observed but it dramatically increases the number of calls to the content key server.
Questions
Should AVContentKeySessions definitely not be reused? Otherwise, how to handle the inconsistency issue described above?
Hi Apple Team,
We have integrated FairPlay Streaming Server SDK v3 into our MDRM platform since 2017, the system works stable and stayed untouched. As you know, both Widevine and Playready have requirements to upgrade the Server SDK regularly. We want to know if Apple imposes similar requirements for upgrading the FPS SDK, or if we may continue using the old one without any updates.
Thanks for your support!
Is it possible to use the AVExternalStorageDevice to access external storage from a connected camera or usb drive (via USB C or Lightning connector) on an iPad/iPhone.
I have tested the following code on an iPhone 14 (iOS 18.1.1) and an iPad Gen 10 (18.3.1), and both return false for:
// returns false on iPhone 14, iPad gen 10
print(AVExternalStorageDeviceDiscoverySession.isSupported)
The following code returns null, when I try to access the external storage discovery session.
// returns null on iOS devices
print(AVExternalStorageDeviceDiscoverySession.shared)
The following returns false, without displaying a permission dialog:
AVExternalStorageDevice.requestAccess(completionHandler: { (granted: Bool) in
// returns false with no permission dialog
print(granted);
What type of iOS devices are supported by AVExternalStorageDeviceDiscoverySession?
What situations has it been used for (e.g. connecting to Camera via the external storage protocol, accessing photos from a SD card with an adapter, accessing photos from usb drive).
Is there are sample code for using the AV External Storage api?
My iOS app can access the iphone media library, but if on Mac M4 is Error Domain=NSCocoaError Domain Code=257
Topic:
Media Technologies
SubTopic:
General
Hello Apple,
i've been using ios for many years and never had any issues with urdu language keyboard, but since the new 18.4 beta update some words are not working correctly as it should like a name of my friend who's name is "راعنیہ" but the new updated version cannot type is together and keep seperating like "راعنی ہ" its so frustrating to use like that and its not just one but so many other words that it just cannot do properly also the new font and no gap concept its hurting my eyes so much while reading or even typing.. i hope apple fixes that asap..
thankyou
Hi There, I have an app which access the media library, to save and load files. Since the IOS 18.2, the access to the media library stopped working.
Now, I've noticed that our App doesn't show in the List of apps with access to Files ( Privacy & Security -> Files & Folders).
Weird behavior is that, one iPhone with iOS 18.3.1 can access to the Files but others no, same iOS version 18.3.1. Test on Simulators (MAC) and works fine also.
My info.plist file have the keys to access media library for long time and hasn't changed (at least in the las 4 years) including the key "Privacy - Media Library Usage Description".
Also, I've noticed, that the message (popup) that request access to the media library, when using the app for the first time, doesn't show up anymore. We request access to the network (wifi) and this message still showing up but no the media library.
I'm using Visual Studio with Xamarin on a MAC.
I really appreciate any help you can because is very odd behavior and this started from the iOS 18.2.
Our iOS/AppleTV video content playback app uses AVPlayer to play HLS video streams and supports both custom and system playback UIs. The Fairplay content key is retrieved using AVContentKeySession. AirPlay is supported too.
When the iPhone is connected to a TV through the lightning Apple Digital AV Adapter (A1438), the app is mirrored as expected.
Problem: when using an iPhone or iPad on iOS 18.1.1, FairPlay-protected HLS streams are not played and a CoreMediaErrorDomain -12035 error is received by the AVPlayerItem. Also, once the issue has occurred, the mirroring freezes (the TV indefinitely displays the app playback screen) although the app works fine on the iOS device.
The content key retrieval works as expected (I can see that 2 content key requests are made by the system by the way, probably one for the local playback and one for the adapter, as when AirPlaying) and the error is thrown after providing the AVContentKeyResponse.
Unfortunately, and as far as I know, there is not documentation on CoreMediaErrorDomain errors so I don't know what -12035 means.
The issue does not occur:
on an iPhone on iOS 17.7 (even with FairPlay-protected HLS streams)
when playing DRM-free video content (whatever the iOS version)
when using the USB-C AV Adapter (whatever the iOS version)
Also worth noting: the issue does not occur with other video playback apps such as Apple TV or Netflix although I don't have any details on the kind of streams these apps play and the way the FairPlay content key is retrieved (if any) so I don't know if it is relevant.
operation couldn't be completed. (CoreMediaErrorDomain error -42709.)
this error shows after update
He has been coming here for the last 10 days. Please!
please correct it as soon as possible
On an iOS 18 phone, I use AVCaptureSession to capture HDR with x420 format. The output CMSampleBuffer is HLG colorspace, the propagated attachments contain kCVImageBufferAmbientViewingEnvironmentKey and kCVImageBufferSceneIlluminationKey. Now I use CAMetalLayer to render the CVPixelBuffer to the screen, but the brightness is brighter than AVSampleBufferDisplayLayer.
Here is my code.
- (void)_updateColorSpaceIfNeed:(CVPixelBufferRef)pixelBuffer {
CAMetalLayer *layer = (CAMetalLayer *)_mtkView.layer;
if (![layer isKindOfClass:CAMetalLayer.class]) return;
layer.wantsExtendedDynamicRangeContent = YES;
CFDataRef ambientViewingEnvironment = (CFDataRef)CVBufferCopyAttachment(pixelBuffer, kCVImageBufferAmbientViewingEnvironmentKey, NULL);
NSData *data = (__bridge NSData *)ambientViewingEnvironment;
if (ambientViewingEnvironment) CFRelease(ambientViewingEnvironment);
CAEDRMetadata *metadata = [CAEDRMetadata HLGMetadataWithAmbientViewingEnvironment:data];
// CAEDRMetadata *metadata = [CAEDRMetadata HLGMetadata];
layer.EDRMetadata = metadata;
layer.pixelFormat = MTLPixelFormatRGBA16Float;
CGColorSpaceRef colorspace = CGColorSpaceCreateWithName(kCGColorSpaceITUR_2100_HLG);
layer.colorspace = colorspace;
if (colorspace) CGColorSpaceRelease(colorspace);
}
Why does the CAEDRMetadata class have "HLGMetadataWithAmbientViewingEnvironment:" and "HLGMetadata" methods, but does not provide the "HLGMetadataWithAmbientViewingEnvironment:sceneIllumination" method?
I want to know how kCVImageBufferAmbientViewingEnvironmentKey and kCVImageBufferSceneIlluminationKey affect tone mapping. Is there any documentation I can refer to?
I found some documentation about Kext, but I heard they have now moved to Dext.
So I was wondering if Dext could completely imitate the previous Kext.
https://developer.apple.com/documentation/kernel/implementing_drivers_system_extensions_and_kexts
This page is written like this
Important
In macOS 11 and later, the kernel doesn’t load a kext if an equivalent DriverKit solution exists. You may continue to use kexts in macOS 10.15 and earlier.
Topic:
Media Technologies
SubTopic:
General
I am playing the protected HLS streams and the authorization token expires in 3 minutes. I am trying to achieve this with 'AVAssetResourceLoaderDelegate'. I can refresh the token and play it, but the problem is in between the session, the player stalls for a small time, LIKE 1 SECOND.
Here's my code :
class APLCustomAVARLDelegate: NSObject, AVAssetResourceLoaderDelegate {
static let httpsScheme = "https"
static let redirectErrorCode = 302
static let badRequestErrorCode = 400
private var token: String?
private var retryDictionary = [String: Int]()
private let maxRetries = 3
private func schemeSupported(_ scheme: String) -> Bool {
let supported = ishttpSchemeValid(scheme)
print("Scheme '\(scheme)' supported: \(supported)")
return supported
}
private func reportError(loadingRequest: AVAssetResourceLoadingRequest, error: Int) {
let nsError = NSError(domain: NSURLErrorDomain, code: error, userInfo: nil)
print("Reporting error: \(nsError)")
loadingRequest.finishLoading(with: nsError)
}
// Handle token renewal requests to prevent playback stalls
func resourceLoader(_ resourceLoader: AVAssetResourceLoader, shouldWaitForRenewalOfRequestedResource renewalRequest: AVAssetResourceRenewalRequest) -> Bool {
print("Resource renewal requested for URL: \(renewalRequest.request.url?.absoluteString ?? "unknown URL")")
// Handle renewal the same way we handle initial requests
guard let scheme = renewalRequest.request.url?.scheme else {
print("No scheme found in the renewal URL.")
return false
}
if isHttpsSchemeValid(scheme) {
return handleHttpsRequest(renewalRequest)
}
print("Scheme not supported for renewal.")
return false
}
private func isHttpsSchemeValid(_ scheme: String) -> Bool {
let isValid = scheme == APLCustomAVARLDelegate.httpsScheme
print("httpsScheme scheme '\(scheme)' valid: \(isValid)")
return isValid
}
private func generateHttpsURL(sourceURL: URL) -> URL? {
// If you need to modify the URL, do it here
// Currently this just returns the same URL
let urlString = sourceURL.absoluteString
print("Generated HTTPS URL: \(urlString)")
return URL(string: urlString)
}
private func handleHttpsRequest(_ loadingRequest: AVAssetResourceLoadingRequest) -> Bool {
print("Handling HTTPS request.")
guard let sourceURL = loadingRequest.request.url,
var redirectURL = generateHttpsURL(sourceURL: sourceURL) else {
print("Failed to generate HTTPS URL.")
reportError(loadingRequest: loadingRequest, error: APLCustomAVARLDelegate.badRequestErrorCode)
return true
}
// Track retry attempts with a dictionary keyed by request URL
let urlString = sourceURL.absoluteString
let currentRetries = retryDictionary[urlString] ?? 0
if currentRetries < maxRetries {
retryDictionary[urlString] = currentRetries + 1
} else {
// Too many retries, report a more specific error
reportError(loadingRequest: loadingRequest, error: NSURLErrorTimedOut)
retryDictionary.removeValue(forKey: urlString)
return true
}
if var urlComponents = URLComponents(url: redirectURL, resolvingAgainstBaseURL: false) {
var queryItems = urlComponents.queryItems ?? []
// Generate a fresh token each time
let freshToken = AESTimeBaseEncription.secureEncryptSecretText()
// Check if the token already exists
if let existingTokenIndex = queryItems.firstIndex(where: { $0.name == "token" }) {
// Update the existing token
queryItems[existingTokenIndex].value = freshToken
} else {
// Add the token if it doesn't exist
queryItems.append(URLQueryItem(name: "token", value: freshToken))
}
urlComponents.queryItems = queryItems
redirectURL = urlComponents.url!
}
let redirectRequest = URLRequest(url: redirectURL)
let response = HTTPURLResponse(url: redirectURL, statusCode: APLCustomAVARLDelegate.redirectErrorCode, httpVersion: nil, headerFields: nil)
print("Redirecting HTTPS to URL: \(redirectURL)")
loadingRequest.redirect = redirectRequest
loadingRequest.response = response
loadingRequest.finishLoading()
// If successful, reset the retry counter
if retryDictionary[urlString] == maxRetries {
retryDictionary.removeValue(forKey: urlString)
}
return true
}
}