I've got a setup using AVAudioEngine with several tone generator nodes, each with a chain of processing nodes, the chains then mixed into the main output.
Generator ➡️ Effect ➡️... ➡️ .mainMixerNode ➡️ .outputNode).
Generator ➡️ Effect ➡️... ⤴️
...
Generator ➡️ Effect ➡️... ⤴️
The user should be able to mute any chain individually. I've found several potential approaches to muting, but not terribly happy with any of them.
Adjust the amplitudes directly in my tone generators. Issue: Consumes CPU even when completely muted. 4 generators adds ~15% cpu, even when all chains are muted.
Detach/attach chains that are muted/unmuted. Issue: Causes loud clicking/popping sounds whenever muted/unmuted.
Fade mixer output volume while detaching/attaching a chain (just cutting the volume immediately to 0 doesn't get rid of the clicking/popping). Issue: Causes all channels to fade during the transition, so not ideal.
The rest of these ideas are variations on making volume control+detatch/attach work for individual chains, since approach #3 worked well.
Add an AVAudioMixer to the end of each chain (just for volume control). Issue: Only the mixer on the final chain functions -- the others block all output. Not sure what's going on there.
Use matrix mixer (for multi-input volume control). Plus detach/attach to reduce CPU if necessary. Not yet attempted, due to perceived complexity and reports of fragility in order of wiring in. A bunch of effort before I even know if it's going to work.
Develop my own fader node to put on the end of each channel. Unlike the tone generator (simple AVSourceNode), developing an effect node seems complex and time consuming. Might not even fix CPU use.
I'm not completely averse to the learning curve of either 5 or 6, but would rather get some guidance on best approach before diving in. They both seem likely to take more effort than I'd like for the simple behavior I'm trying to achieve.
Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.
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Hello!
I have a problem with getting album extended info from users library. Note that app authorised to use Apple Music according documentation.
I get albums from users library with this code:
func getLibraryAlbums() async throws -> MusicItemCollection<Album> {
let request = MusicLibraryRequest<Album>()
let response = try await request.response()
return response.items
}
This is an example of Albums request respones:
{
"data" : [
{
"meta" : {
"musicKit_identifierSet" : {
"isLibrary" : true,
"id" : "1945382328890400383",
"dataSources" : [
"localLibrary",
"legacyModel"
],
"type" : "Album",
"deviceLocalID" : {
"databaseID" : "37336CB19CF51727",
"value" : "1945382328890400383"
},
"catalogID" : {
"kind" : "adamID",
"value" : "1173535954"
}
}
},
"id" : "1945382328890400383",
"type" : "library-albums",
"attributes" : {
"artwork" : {
"url" : "musicKit:\/\/artwork\/transient\/{w}x{h}?id=4A2F444C%2D336D%2D49EA%2D90C8%2D13C547A5B95B",
"width" : 0,
"height" : 0
},
"genreNames" : [
"Pop"
],
"trackCount" : 1,
"artistName" : "Сара Окс",
"isAppleDigitalMaster" : false,
"audioVariants" : [
"lossless"
],
"playParams" : {
"catalogId" : "1173535954",
"id" : "1945382328890400383",
"musicKit_persistentID" : "1945382328890400383",
"kind" : "album",
"musicKit_databaseID" : "37336CB19CF51727",
"isLibrary" : true
},
"name" : "Нимфомания - Single",
"isCompilation" : false
}
},
{
"meta" : {
"musicKit_identifierSet" : {
"isLibrary" : true,
"id" : "-8570883332059662437",
"dataSources" : [
"localLibrary",
"legacyModel"
],
"type" : "Album",
"deviceLocalID" : {
"value" : "-8570883332059662437",
"databaseID" : "37336CB19CF51727"
},
"catalogID" : {
"kind" : "adamID",
"value" : "1618488499"
}
}
},
"id" : "-8570883332059662437",
"type" : "library-albums",
"attributes" : {
"isCompilation" : false,
"genreNames" : [
"Pop"
],
"trackCount" : 1,
"artistName" : "TIMOFEEW & KURYANOVA",
"isAppleDigitalMaster" : false,
"audioVariants" : [
"lossless"
],
"playParams" : {
"catalogId" : "1618488499",
"musicKit_persistentID" : "-8570883332059662437",
"kind" : "album",
"id" : "-8570883332059662437",
"musicKit_databaseID" : "37336CB19CF51727",
"isLibrary" : true
},
"artwork" : {
"url" : "musicKit:\/\/artwork\/transient\/{w}x{h}?id=BEA6DBD3%2D8E14%2D4A10%2D97BE%2D8908C7C5FC2C",
"width" : 0,
"height" : 0
},
"name" : "Не звони - Single"
}
},
...
]
}
In AlbumView using task: view modifier I request extended information about the album with this code:
func loadExtendedInfo(_ album: Album) async throws -> Album {
let response = try await album.with([.tracks, .audioVariants, .recordLabels], preferredSource: .library)
return response
}
but in the response some of the fields are always nil, for example recordLabels, releaseDate, url, editorialNotes, copyright.
Please tell me what I'm doing wrong?
When multiple identical songs are added to a playlist, Playlist.Entry.id uses a suffix-based identifier (e.g. songID_0, songID_1, etc.). Removing one entry causes others to shift, changing their .id values. This leads to diffing errors and collection view crashes in SwiftUI or UIKit when entries are updated.
Steps to Reproduce:
Add the same song to a playlist multiple times.
Observe .id.rawValue of entries (e.g. i.SONGID_0, i.SONGID_1).
Remove one entry.
Fetch playlist again — note the other IDs have shifted.
FB18879062
I’m currently working on a project where I capture both depth frames and RGB frames using AVCaptureDataOutputSynchronizer. Depth frames are stored as raw binary data and RGB frames are saved with AVAssetWriter.
The issue I’m facing is that AVAssetWriter enforces a fixed framerate, meaning it adds or discards frames to maintain that rate (as I understand it). This causes a desynchronization between the depth and RGB frames, which is a problem because I need each depth frame to be exactly matched with the corresponding RGB frame as they were captured.
How can I ensure that the RGB frames are saved without AVAssetWriter modifying the frame count?
I'm streaming mp3 audio data using URLSession/AudioFileStream/AVAudioConverter and getting occasional silent buffers and glitches (little bleeps and whoops as opposed to clicks). The issues are present in an offline test, so this isn't an issue of underruns.
Doing some buffering on the input coming from the URLSession (URLSessionDataTask) reduces the glitches/silent buffers to rather infrequent, but they do still happen occasionally.
var bufferedData = Data()
func parseBytes(data: Data) {
bufferedData.append(data)
// XXX: this buffering reduces glitching
// to rather infrequent. But why?
if bufferedData.count > 32768 {
bufferedData.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) in
guard let baseAddress = bytes.baseAddress else { return }
let result = AudioFileStreamParseBytes(audioStream!,
UInt32(bufferedData.count),
baseAddress,
[])
if result != noErr {
print("❌ error parsing stream: \(result)")
}
}
bufferedData = Data()
}
}
No errors are returned by AudioFileStream or AVAudioConverter.
func handlePackets(data: Data,
packetDescriptions: [AudioStreamPacketDescription]) {
guard let audioConverter else {
return
}
var maxPacketSize: UInt32 = 0
for packetDescription in packetDescriptions {
maxPacketSize = max(maxPacketSize, packetDescription.mDataByteSize)
if packetDescription.mDataByteSize == 0 {
print("EMPTY PACKET")
}
if Int(packetDescription.mStartOffset) + Int(packetDescription.mDataByteSize) > data.count {
print("❌ Invalid packet: offset \(packetDescription.mStartOffset) + size \(packetDescription.mDataByteSize) > data.count \(data.count)")
}
}
let bufferIn = AVAudioCompressedBuffer(format: inFormat!, packetCapacity: AVAudioPacketCount(packetDescriptions.count), maximumPacketSize: Int(maxPacketSize))
bufferIn.byteLength = UInt32(data.count)
for i in 0 ..< Int(packetDescriptions.count) {
bufferIn.packetDescriptions![i] = packetDescriptions[i]
}
bufferIn.packetCount = AVAudioPacketCount(packetDescriptions.count)
_ = data.withUnsafeBytes { ptr in
memcpy(bufferIn.data, ptr.baseAddress, data.count)
}
if verbose {
print("handlePackets: \(data.count) bytes")
}
// Setup input provider closure
var inputProvided = false
let inputBlock: AVAudioConverterInputBlock = { packetCount, statusPtr in
if !inputProvided {
inputProvided = true
statusPtr.pointee = .haveData
return bufferIn
} else {
statusPtr.pointee = .noDataNow
return nil
}
}
// Loop until converter runs dry or is done
while true {
let bufferOut = AVAudioPCMBuffer(pcmFormat: outFormat, frameCapacity: 4096)!
bufferOut.frameLength = 0
var error: NSError?
let status = audioConverter.convert(to: bufferOut, error: &error, withInputFrom: inputBlock)
switch status {
case .haveData:
if verbose {
print("✅ convert returned haveData: \(bufferOut.frameLength) frames")
}
if bufferOut.frameLength > 0 {
if bufferOut.isSilent {
print("(haveData) SILENT BUFFER at frame \(totalFrames), pending: \(pendingFrames), inputPackets=\(bufferIn.packetCount), outputFrames=\(bufferOut.frameLength)")
}
outBuffers.append(bufferOut)
totalFrames += Int(bufferOut.frameLength)
}
case .inputRanDry:
if verbose {
print("🔁 convert returned inputRanDry: \(bufferOut.frameLength) frames")
}
if bufferOut.frameLength > 0 {
if bufferOut.isSilent {
print("(inputRanDry) SILENT BUFFER at frame \(totalFrames), pending: \(pendingFrames), inputPackets=\(bufferIn.packetCount), outputFrames=\(bufferOut.frameLength)")
}
outBuffers.append(bufferOut)
totalFrames += Int(bufferOut.frameLength)
}
return // wait for next handlePackets
case .endOfStream:
if verbose {
print("✅ convert returned endOfStream")
}
return
case .error:
if verbose {
print("❌ convert returned error")
}
if let error = error {
print("error converting: \(error.localizedDescription)")
}
return
@unknown default:
fatalError()
}
}
}
How can I use my RGB Curve points:
let redCurve = [CIVector(x: 0, y: 0), CIVector(x: 0.235, y: 0.152), CIVector(x: 0.5, y: 0.5), CIVector(x: 1, y: 1)]
let greenCurve = [CIVector(x: 0, y: 0), CIVector(x: 0.247, y: 0.196), CIVector(x: 0.5, y: 0.5), CIVector(x: 1, y: 1)]
let blueCurve = [CIVector(x: 0, y: 0), CIVector(x: 0.235, y: 0.184), CIVector(x: 0.466, y: 0.466), CIVector(x: 1, y: 1)]
in colorCurvesFilter which I've found in Apple Docs:
func colorCurves(inputImage: CIImage) -> CIImage {
let colorCurvesEffect = CIFilter.colorCurves()
colorCurvesEffect.inputImage = inputImage
colorCurvesEffect.curvesDomain = CIVector(x: 0, y: 1)
colorCurvesEffect.curvesData = Data(
bytes: [Float32]([
0.0,0.0,0.0,
0.8,0.8,0.8,
1.0,1.0,1.0
]), count: 36)
colorCurvesEffect.colorSpace = CGColorSpaceCreateDeviceRGB()
return colorCurvesEffect.outputImage!
}
I'm using AVFoundation to make a multi-track editor app, which can insert multiple track and clip, including scale some clip to change the speed of the clip, (also I'm not sure whether AVFoundation the best choice for me) but after making the scale with scaleTimeRange API, there is some short noise sound in play back. Also, sometimes it's fine when play AVMutableCompostion using AVPlayer with AVPlayerItem, but after exporting with AVAssetReader, will catch some short noise sounds in result file.... Not sure why.
Here is the example project, which can build and run directly. https://github.com/luckysmg/daily_images/raw/refs/heads/main/TestDemo.zip
I am developing a VOD playback app, but when I stream video to an external monitor connected via HDMI with Lightning on iOS 18 or later, the screen goes dark and I cannot confirm playback.
The app I am developing does not detect the HDMI and display the Player separately, but simply mirrors the video.
We have confirmed that the same phenomenon occurs with other services, but we were able to confirm playback with some services such as Apple TV.
Please let us know if there are any other necessary settings such as video certificates required for video playback.
We would also like to know if the problem occurs with iOS 18 or later.
Topic:
Media Technologies
SubTopic:
Audio
Before you post —Camera doesn't work on the Simulator— that's no longer true. I've made a solution that makes the Simulator believe there's an actual hardware device connected, allowing users to stream the macOS camera to the iOS Simulator (see for more info RocketSim's documentation: https://docs.rocketsim.app/features/hzQMSrSga7BGWvxdNVdwYs/simulator-camera-support/58tQ5jvevLNSnyUEA7VgAv)
Now, it works for VNDocumentCameraViewController, but when I try opening DataScannerViewController, I directly run into:
Failed to start scanning: The operation couldn’t be completed. (VisionKit.DataScannerViewController.ScanningUnavailable error 0.)
My question:
How does this view controller determine whether scanning is available?
Is there a certain capability the available AVCaptureDevice's need to support maybe?
Any direction would be helpful for me to make this work for developers, making them build apps faster!
I'm creating an app that uses AVCaptureSession to pass camera input to AVCaptureMetadataOutput type set [metaout setMetadataObjectTypes:@[AVMetadataObjectTypeFace]] and scan Face.
After updating to OS 26 Beta2 and iOS 26 Beta2, an issue has occurred where the delegate method of AVCaptureMetadataOutputObjectsDelegate is not called on some devices. The following devices are experiencing this issue.
iPad (9th Gen)
iPad air (4th Gen)
iPhone 15
This issue has not occur on any other devices I have.
I tried running the AVFoundation sample code on the Apple Developer site on the above device. The same problem still occurs. https://developer.apple.com/documentation/avfoundation/capture_setup/avcambarcode_detecting_barcodes_and_faces
Are any additional settings required after OS 26 beta and iOS 26 beta? Or is there some problem on the OS side?
I want to create a Live Photo. The project includes a .jpg image and a .mov video (2 seconds).
Two permissions in xcode have been added:
Privacy - Photo Library Usage Description
Privacy - Photo Library Additions Usage Description
Simulate: iphone 16, ios 18.3
The codes in ContentView.swift :
private func saveLivePhoto(imageURL: URL, videoURL: URL, completion: @escaping (Bool, Error?) -> Void) {
PHPhotoLibrary.shared().performChanges {
let creationRequest = PHAssetCreationRequest.forAsset()
let options = PHAssetResourceCreationOptions()
options.shouldMoveFile = false
creationRequest.addResource(with: .photo, fileURL: imageURL, options: options)
creationRequest.addResource(with: .pairedVideo, fileURL: videoURL, options: options)
} completionHandler: { success, error in
DispatchQueue.main.async {
print(error)
completion(success, error)
}
}
}
guard let imageURL = Bundle.main.url(forResource: "livephoto", withExtension: "jpeg"),
let videoURL = Bundle.main.url(forResource: "livephoto", withExtension: "mov") else {
showAlertMessage(title: "error", message: "cant find Live Photo ")
return
}
print("imageURL: \(imageURL)")
print("videoURL: \(videoURL)")
saveLivePhoto(imageURL: imageURL, videoURL: videoURL) { success, error in
if success {
xxxxx
} else {
xxxxx
}
}
Really need help, thanks
My app Balletrax is a music player for people to use while they teach ballet. Used to be you could silence notifications during use, but now the customer seems to have to know how to use Focus mode, remember to turn it on and off, and have to check the notifications one does and doesn't want to use. Is there no way to silence all notifications when the app is in use?
We have a React website build to scan qr codes. The website is properly working for Android devices but for Iphone we see a camera glitch causing delay in scan which is unexpected.
Website URL : https://react-qr-code-scanner-app.vercel.app/
Topic:
Media Technologies
SubTopic:
Photos & Camera
We are planning to develop an application using the Apple Music API.
We would like to design our system based on the details of the rate limits mentioned below and have a few questions:
https://developer.apple.com/documentation/applemusicapi/generating-developer-tokens#Request-Rate-Limiting
Regarding the Catalog API (/v1/catalog/*), we understand that server-side caching is enabled, making it less likely to reach the rate limit. Is this understanding correct? (Excluding the search API)
For APIs like the Library API (/v1/me/library/*), where responses vary by user, we assume they are more likely to reach the rate limit. Is this correct?
We plan to implement optimizations to minimize unnecessary API calls. Given this, would the current Music API be able to handle a significant increase in users? (Assuming a DAU of around 100,000 to 1,000,000)
If the API cannot support this scale, would it be allowed under Apple’s policy to cache responses from the Catalog API (/v1/catalog/*) via our proxy server to avoid hitting the rate limit?
The third question is the one we most want to confirm.
Hey,
Quick question. I noticed that Adobe's new app, Project Indigo, allows you to open the app using the Camera Control button. However, when your device is locked it just shows this screen:
Would this normally be approved by the Appstore approval process? I ask because I would like to do something similar with my camera app.
I know that this is not the best user experience, but my apps UI is not built in Swift and I don't have the resources to build the UI again. At least this way the user experience would be improved from what it is now, where users cannot even launch the app. I get many requests per week about this feature and would love to improve the UX for my users, even if it's not the best possible.
Thanks,
Alex
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.
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 scenario we are seeing on an even smaller number of users is that the following call:
AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back)
returns nil. A quick look at our error reports show this happening on iPhone XR, 13 and 14 models. They should all support this device type.
Any help on investigating these issue would be greatly appreciated!
I'm trying to load Music Kit on the server with solid js. I can confirm that my implementation has been sufficient to return authentication tokens and for MusicKit.isAuthorized to return true. My issue is that if I reload the page, it only succeeds intermittently (perhaps 25% of the time?). My question is - what is wrong with my implementation? Removing the async keyword ensures it loads every time but playing and queuing music no longer works. I'm currently assuming this is an SSR issue but the docs haven't explicitly specified this isn't possible.
I have the following boilerplate:
export default createHandler(
() => (
<StartServer
document={({ assets, children, scripts }) => {
return (
<html lang="en">
<head>
<meta name="apple-music-developer-token" content={authResult.token} />
<meta name="apple-music-app-name" content="app name" />
<meta name="apple-music-app-build" content="1978.4.1" />
{assets}
<script
src="https://js-cdn.music.apple.com/musickit/v3/musickit.js"
async
/>
</head>
<body>
<div id="app">{children}</div>
{scripts}
</body>
</html>
)
}}
/>
))
When I first load my app, I'll encounter:
musickit.js:13 Uncaught TypeError: Cannot read properties of undefined (reading 'node')
at musickit.js:13:10194
at musickit.js:13:140
at musickit.js:13:209
The intermittence signals an issue relating to the async keyword. An expansion on this issue can be found here.
Hey folks, I'm running into an odd issue suddenly with an app that had a working MusicKit integration before.
I'm using ApplicationMusicPlayer to play Apple Music albums and songs. I'm testing on a physical device, signed in to Apple ID, and with a valid subscription. Apple Music via the first-party app works entirely fine on this device.
Attempting to play back any content at all gives the log:
<ICUserIdentityStoreACAccountBackend: 0x1070bf3e0> Failed to initialize primary apple account, error=Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store}
[ICUserIdentityStore] - initializing account histories with activeAccountDSID = nil, activeLockerAccountDSID = nil, timestamp = 14605951908
[ICUserIdentityStore] Failed to fetch local store account with error: Error Domain=ICError Code=-7013 "Client is not entitled to access account store" UserInfo={NSDebugDescription=Client is not entitled to access account store}.
The album artwork, track names, etc, all appear in the control center playback controls, but the music doesn't play. Trying to trigger playback with control center just results in it skipping to the next track, which doesn't play either.
This exact code used to work. I have the MusicKit service selected in Apple Connect. Since this isn't entitlement-based, I'm not sure how else to check that I'm set up correctly.
I've tried deleting/reinstalling the app, restarting the device, cleaning/rebuilding, and deleting DerivedData, to no avail.
Any help?
Running Xcode 16.4 (16F6), testing on iOS 18.5 (22F76)
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.