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Why is the volume very low when using the real-time recording and playback feature with AEC?
I’ve been researching how to achieve a recording playback effect in iOS similar to the hands-free calling effect in the system’s phone app. How can this be implemented? I tried using the voice chat recording method, but found that the volume of the speaker output is too low. How should this issue be addressed? I couldn’t find a suitable API. Could you provide me with some documentation or sample code? Thank you.
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429
Feb ’25
Issue using Siphon Tap on input AudioQueue
Hi all, I've developed an audio DSP application in C++ using AudioToolbox and CoreAudio on MacOS 14.4.1 with Xcode 15. I use an AudioQueue for input and another for output. This works great. I'm now adding real-time audio analysis eg spectral analysis. I want this to run independently of my audio processing so it can not interfere with audio playback. Taps on AudioQueues seem to be a good way of doing this... Since the analytics won't modify the audio data, I am using a Siphon Tap by setting the AudioQueueProcessingTapFlags to kAudioQueueProcessingTap_PreEffects | kAudioQueueProcessingTap_Siphon; This works fine on my output queue. However, on my input queue the Tap callback is called once and then a EXC_BAD_ACCESS occurs - screen shot below. NB: I believe that a callback should only call AudioQueueProcessingTapGetSourceAudio when not using a Siphon, so I don't call it. Relevant code: AudioQueueProcessingTapCallback tap_callback) { // Makes an audio tap for a queue void * tap_data_ptr = NULL; AudioQueueProcessingTapFlags tap_flags = kAudioQueueProcessingTap_PostEffects | kAudioQueueProcessingTap_Siphon; uint32_t max_frames = 0; AudioStreamBasicDescription asbd; AudioQueueProcessingTapRef tap_ref; OSStatus status = AudioQueueProcessingTapNew(queue_ref, tap_callback, tap_data_ptr, tap_flags, &max_frames, &asbd, &tap_ref); if (status != noErr) printf("Error while making Tap\n"); else printf("Successfully made tap\n"); } void tapper(void * tap_data, AudioQueueProcessingTapRef tap_ref, uint32_t number_of_frames_in, AudioTimeStamp * ts_ptr, AudioQueueProcessingTapFlags * tap_flags_ptr, uint32_t * number_of_frames_out_ptr, AudioBufferList * buf_list) { // Callback function for audio queue tap printf("Tap callback"); }``` Image of exception stack provided by Xcode: ![]("https://developer.apple.com/forums/content/attachment/27479e8d-a118-459b-aa2d-7e30528910e3" "title=Screenshot 2025-06-14 at 1.29.14 PM.png;width=932;height=562") What have I missed? Appreciate any help you learned folks may be able to provide. Best, Geoff.
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Jun ’25
Can we say that HLS uses UDP?
Hello, Apple video engineers. According to the official documentation, HLS is built on HTTP and traditionally ran on top of TCP. However, with the introduction of HTTP/3, which uses QUIC (runs on top of UDP), I would like to clarify the following: Has the official HLS specification changed in a way that allows it to be considered UDP-based when using HTTP/3? And is it fair to say that HLS supports UDP since the transport can go over HTTP/3 and QUIC? Would it be more accurate to say that HLS remains HTTP-dependent, and the transport protocol (TCP or QUIC) only determines how HTTP requests are delivered? My thoughts: Since HTTP/3 uses QUIC running over UDP, we still can't say that HLS supports UDP in a classical way, as it is introduced in RTP, RTSP, SRT.
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434
Feb ’25
Wi-Fi Access Point Not Reconnecting While AVAudioSession Is Active
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!
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174
Jun ’25
How to override the default USB video
According to the doc, I did a simple demo to verify. My env: ProductName: macOS ProductVersion: 15.5 BuildVersion: 24F74 2.4 GHz 四核Intel Core i5 Info.plist: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>IOKitPersonalities</key> <dict> <key>UVCamera</key> <dict> <key>CFBundleIdentifierKernel</key> <string>com.apple.kpi.iokit</string> <key>IOClass</key> <string>IOUserService</string> <key>IOMatchCategory</key> <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string> <key>IOProviderClass</key> <string>IOUserResources</string> <key>IOResourceMatch</key> <string>IOKit</string> <key>IOUserClass</key> <string>UVCamera</string> <key>IOUserServerName</key> <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string> <key>IOProbeScore</key> <integer>100000</integer> <key>idVendor</key> <integer>1452</integer> <key>idProduct</key> <integer>34068</integer> </dict> </dict> <key>OSBundleUsageDescription</key> <string></string> </dict> </plist> UVCamera.cpp // // UVCamera.cpp // UVCamera // // Created by DTEN on 2025/6/12. // #include <os/log.h> #include <DriverKit/IOUserServer.h> #include <DriverKit/IOLib.h> #include "UVCamera.h" kern_return_t IMPL(UVCamera, Start) { kern_return_t ret; ret = Start(provider, SUPERDISPATCH); os_log(OS_LOG_DEFAULT, "Hello World"); return ret; } UVCamera.iig // // UVCamera.iig // UVCamera // // Created by DTEN on 2025/6/12. // #ifndef UVCamera_h #define UVCamera_h #include <Availability.h> #include <DriverKit/IOService.iig> class UVCamera: public IOService { public: virtual kern_return_t Start(IOService * provider) override; }; #endif /* UVCamera_h */ Then I build by xcode and mv it to /Library/DriverExtensions: sudo mv com.lqs.MyVirtualCam.UVCamera.dext /Library/DriverExtensions sudo kmutil install -R / -r /Library/DriverExtensions kmutil rebuild done However,the dext can't be loaded: kmutil showloaded --list-only | grep UVCamera No variant specified, falling back to release What's the problem? anyone can help me?
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Jun ’25
PHPickerResult take loong time to load large video
On some devices, loadFileRepresentation(forTypeIdentifier: completionHandler) take a loong time(about two minute) to callback result for some large video(about 200 MB, take by device camera). environment: Model: iPhone 12 Model Number: MGGM3CH/A iOS Version: 18.3.2 PHPickerResult.NSItemProvider.loadFileRepresentation() // import PhotosUI func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) { picker.dismiss(animated: true, completion: nil) guard let provider = results.last?.itemProvider else { return } guard provider.hasItemConformingToTypeIdentifier(UTType.movie.identifier) else { return } Task { provider.loadFileRepresentation(forTypeIdentifier: UTType.movie.identifier) { url, error in guard let url = url else { return } // Do some stuff... } } } ps: I also try some other function, eg: provide.loadItem(forTypeIdentifier:), but not work too.
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Mar ’25
AVSpeechSynthesisVoices available on device
Hello there! Is there any list of voices that are always available on iOS/iPadOS devices? It seems that AVSpeechSynthesisVoice(identifier: "com.apple.voice.compact.en-US.Samantha") is always available on all devices. I thought that AVSpeechSynthesisVoice(identifier: "com.apple.ttsbundle.siri_Nicky_en-US_compact") and AVSpeechSynthesisVoice(identifier: "com.apple.ttsbundle.siri_Aaron_en-US_compact") were available by default on certain newer devices. Is this true? I also noticed that on the same iPad where I was using those 2 voices (Nicky and Aaron) - when I updated to the iPadOS 26 beta, those voices were no longer available. Any information you can share about which voices should be reliably available on which devices would be extremely helpful for our development. Thanks so much!
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Jun ’25
Some questions about musickit
We are developing an apple music app on phone, the developed web works fine on chrome, but when i load it on webivew on my phone, i can't play the first song, We doubt that the drm init, key exchange, session creation was on the music.play() function, while we trigger the play, the drm or session was not ok for play a real song, so it got an error so we may wanna know: what about the realative process of drm, key, session, etc in the play() function? are there some state detect function to show weather the drm is ok?
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Mar ’25
How correctly setup AVSampleBufferDisplayLayer
How can I setup correctly AVSampleBufferDisplayLayer for video display when I have input picture format kCVPixelFormatType_32BGRA? Currently video i visible in simulator, but not iPhone, miss I something? Render code: var pixelBuffer: CVPixelBuffer? let attrs: [String: Any] = [ kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA, kCVPixelBufferWidthKey as String: width, kCVPixelBufferHeightKey as String: height, kCVPixelBufferBytesPerRowAlignmentKey as String: width * 4, kCVPixelBufferIOSurfacePropertiesKey as String: [:] ] let status = CVPixelBufferCreateWithBytes( nil, width, height, kCVPixelFormatType_32BGRA, img, width * 4, nil, nil, attrs as CFDictionary, &pixelBuffer ) guard status == kCVReturnSuccess, let pb = pixelBuffer else { return } var formatDesc: CMVideoFormatDescription? CMVideoFormatDescriptionCreateForImageBuffer( allocator: nil, imageBuffer: pb, formatDescriptionOut: &formatDesc ) guard let format = formatDesc else { return } var timingInfo = CMSampleTimingInfo( duration: .invalid, presentationTimeStamp: currentTime, decodeTimeStamp: .invalid ) var sampleBuffer: CMSampleBuffer? CMSampleBufferCreateForImageBuffer( allocator: kCFAllocatorDefault, imageBuffer: pb, dataReady: true, makeDataReadyCallback: nil, refcon: nil, formatDescription: format, sampleTiming: &timingInfo, sampleBufferOut: &sampleBuffer ) if let sb = sampleBuffer { if CMSampleBufferGetPresentationTimeStamp(sb) == .invalid { print("Invalid video timestamp") } if (displayLayer.status == .failed) { displayLayer.flush() } DispatchQueue.main.async { [weak self] in guard let self = self else { print("Lost reference to self drawing") return } displayLayer.enqueue(sb) } frameIndex += 1 }
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179
Apr ’25
How to display artwork images from MusicKit with UIKit?
In SwiftUI there is a built-in component for displaying album artworks called Artwork but there is no equivalent for UIKit. My current approach is to use the .url() method to read image's URL and download the image or read it from the disk but the performance is much worse than it was previously with MPMediaItem's artworkImage method. let artworkQueue = DispatchQueue( label: "MusicKit-ArtworkQueue", qos: .default, attributes: .concurrent ) let artworkSemaphore = DispatchSemaphore(value: 5) extension Song { func artworkImage(for size: CGSize, completion: @escaping (UIImage?) -> Void) { artworkQueue.async { artworkSemaphore.wait() defer { artworkSemaphore.signal() } let imageURL = artwork?.url( width: Int(size.width), height: Int(size.height) ) // I hate doing this as it might very well break in the future guard let imageURL, imageURL.scheme == "musicKit" else { return completion(nil) } guard let imageData = try? Data(contentsOf: imageURL), let image = UIImage(data: imageData) else { return completion(nil) } completion(image) } } } I really dislike this approach because it feels hacky but somewhat works. You might ask what's the semaphore for? Well, without it I could notice that MusicKit was choking and after reading too many artworks at once. Can someone from Apple please provide us with an example on how to use MusicKit with UIKit properly? Ideally (IMO) we would have a method defined on Song and other MusicKit structures that returns the image for us, just like MPMediaItem had the .artwork() method. It would make our lives so much easier.
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1k
Mar ’25
When deleting photos, encountered PHPhotosError.operationInterrupted (3301).
Hi, I’ve developed a photo app that includes a photo deletion feature. Some users have reported encountering PHPhotosError.operationInterrupted (3301) when attempting to delete photos. Initially, I suspected that some of the assets might have a sourceType of typeiTunesSynced, since the documentation notes that iTunes-synced assets cannot be edited or deleted. However, after checking the logs, all of the assets involved are of typeUserLibrary. Additionally, the user mentioned that some photos in the iPhone Photos do not show a delete button. I’m unsure whether the absence of the delete button is related to the 3301 error. I’d like to confirm the following: Under what conditions does PHPhotosError.operationInterrupted (3301) occur, and how should it be handled? Why do some photos in the iPhone Photos not show a delete button? The code for deleting photos is as follows: PHPhotoLibrary *library = [PHPhotoLibrary sharedPhotoLibrary]; [library performChanges:^{ PHFetchResult *assetsToBeDeleted = [PHAsset fetchAssetsWithLocalIdentifiers:delUrls options:nil]; if (assetsToBeDeleted) { [PHAssetChangeRequest deleteAssets:assetsToBeDeleted]; } } completionHandler:^(BOOL success, NSError *error) {
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121
Jun ’25
How to match music with shazamkit for Android ?
Hi all, i can successfully match music using shazamkit on Apple using SwiftUI, a simple app that let user to load an audio file and exctracts the relative match, while i am unable to match music using shamzamkit on Android. I am trying to make the same simple app but i cannot match music as i get MATCH_ATTEMPT_FAILED every time i try to. I don't know what i am doing wrong but the shazam part in the kotlin Android code is in this method : suspend fun processAudioFileInBackground( filePath: String, developerTokenProvider: DeveloperTokenProvider ) = withContext(Dispatchers.IO) { val bufferSize = 1024 * 1024 val audioFile = FileInputStream(filePath) val byteBuffer = ByteBuffer.allocate(bufferSize) byteBuffer.order(ByteOrder.LITTLE_ENDIAN) var bytesRead: Int while (audioFile.read(byteBuffer.array()).also { bytesRead = it } != -1) { val signatureGenerator = (ShazamKit.createSignatureGenerator(AudioSampleRateInHz.SAMPLE_RATE_44100) as ShazamKitResult.Success).data signatureGenerator.append(byteBuffer.array(), bytesRead, System.currentTimeMillis()) val signature = signatureGenerator.generateSignature() println("Signature: ${signature.durationInMs}") val catalog = ShazamKit.createShazamCatalog(developerTokenProvider, Locale.ENGLISH) val session = (ShazamKit.createSession(catalog) as ShazamKitResult.Success).data val matchResult = session.match(signature) println("MatchResult : $matchResult") setMatchResult(matchResult) byteBuffer.clear() } audioFile.close() } I noticed that changing Locale in catalog creation results in different result as i get NoMatch without exception. Can you please help me with this?
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Apr ’25
Do we need an MFi authentication chip to send video/commands to iPhone?
Hello, my company is developing a product that will send data to/from the phone over cable and Wi-Fi. I have three questions: Do we need an MFi authentication chip in our product if we plan to send video and commands to the iPhone/iPad over USB or Lightning cable? Likewise, do we need an MFI authentication chip for communication over Wi-Fi? (Informal research suggests that the answer is no to this one.) And, do we even still need MFI certification at all for Wi-Fi comms? (We are not using HomeKit.) Thank you!
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455
Feb ’25
Where is the License Agreement for Android version of ShazamKit?
I have integrated the ShazamKit SDK into my iOS app and would like to implement the same functionality in my Android app. My question is: Can I use the Android version of the ShazamKit SDK for commercial purposes? After extensive research, I could not find any official information regarding the license of the Android version of the ShazamKit SDK. Could you please provide a formal license statement?
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129
Apr ’25
AirDropped Videos from Photos Save to Files Instead of Photos on Receiving Device
My app allows users to capture and save videos to the Photos app using the following Swift code: PHPhotoLibrary.shared().performChanges { PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: fileURL) } completionHandler: { success, error in Videos are successfully saved to Photos and play correctly. However, users report that when they AirDrop these videos from the Photos app to another device (e.g., iPad to iPhone), the videos are saved in the Files app on the receiving device instead of the Photos app. This issue is more common with higher-resolution videos, such as 2K, recorded in HEVC format at 30 fps. I wasn't able to reproduce the issue locally. I've found a thread in public apple forum: https://discussions.apple.com/thread/255276865?sortBy=rank but I wonder maybe there are some special flags that I should clear or add to my videos (e.g. PHAssetChangeRequest)? Thank you!
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119
May ’25
H.265 Decoding with VideoToolBox
I am creating an app that decodes H.265 elementary streams on iOS. I use VideoToolBox to decode from H.265 to NV12. The decoded data is enqueued in the CMSampleBufferDisplayLayer as a CMSampleBuffer. However, nothing is displayed in the VideoPlayerView. It remains black. The decoding in VideoToolBox is successful. I confirmed this by saving the NV12 data in the CMSampleBuffer to a file and displaying it using a tool. Why is nothing displayed in the VideoPlayerView? I can provide other source code as well. // // VideoPlayerView.swift // H265Decoder // // Created by Kohshin Tokunaga on 2025/02/15. // import SwiftUI import AVFoundation struct VideoPlayerView: UIViewRepresentable { // Return an H265Player as the coordinator, and start playback there. func makeCoordinator() -> H265Player { H265Player() } func makeUIView(context: Context) -> UIView { let uiView = UIView(frame: .zero) // Base layer for attaching sublayers uiView.backgroundColor = .black // Screen background color (for iOS) // Create the display layer and add it to uiView.layer let displayLayer = context.coordinator.displayLayer displayLayer.frame = uiView.bounds displayLayer.backgroundColor = UIColor.clear.cgColor uiView.layer.addSublayer(displayLayer) // Start playback context.coordinator.startPlayback() return uiView } func updateUIView(_ uiView: UIView, context: Context) { // Reset the frame of the AVSampleBufferDisplayLayer when the view's size changes. let displayLayer = context.coordinator.displayLayer displayLayer.frame = uiView.layer.bounds // Optionally update the layer's background color, etc. uiView.backgroundColor = .black displayLayer.backgroundColor = UIColor.clear.cgColor // Flush transactions if necessary CATransaction.flush() } } // // H265Player.swift // H265Decoder // // Created by Kohshin Tokunaga on 2025/02/15. // import Foundation import AVFoundation import CoreMedia class H265Player: NSObject, VideoDecoderDelegate { let displayLayer = AVSampleBufferDisplayLayer() private var decoder: H265Decoder? override init() { super.init() // Initial configuration for the display layer displayLayer.videoGravity = .resizeAspect // Initialize the decoder (delegate = self) decoder = H265Decoder(delegate: self) // For simple playback, set isBaseline to true decoder?.isBaseline = true } func startPlayback() { // Load the file "cars_320x240.h265" guard let url = Bundle.main.url(forResource: "temp2", withExtension: "h265") else { print("File not found") return } do { let data = try Data(contentsOf: url) // Set FPS and video size as needed let packet = VideoPacket(data: data, type: .h265, fps: 30, videoSize: CGSize(width: 1080, height: 1920)) // Decode as a single packet decoder?.decodeOnePacket(packet) } catch { print("Failed to load file: \(error)") } } // MARK: - VideoDecoderDelegate func decodeOutput(video: CMSampleBuffer) { // When decoding is complete, send the output to AVSampleBufferDisplayLayer displayLayer.enqueue(video) } func decodeOutput(error: DecodeError) { print("Decoding error: \(error)") } }
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384
Feb ’25
PhotosPicker obtains the result information of the selected video
In the AVP project, a selector pops up, only wanting to filter spatial videos. When selecting the material of one of the spatial videos, the selection result returns empty. How can we obtain the video selected by the user and get the path and the URL of the file The code is as follows: PhotosPicker(selection: $selectedItem, matching: .videos) { Text("Choose a spatial photo or video") } func loadTransferable(from imageSelection: PhotosPickerItem) -> Progress { return imageSelection.loadTransferable(type: URL.self) { result in DispatchQueue.main.async { // guard imageSelection == self.imageSelection else { return } print("加载成功的图片集合:(result)") switch result { case .success(let url?): self.selectSpatialVideoURL = url print("获取视频链接:(url)") case .success(nil): break // Handle the success case with an empty value. case .failure(let error): print("spatial错误:(error)") // Handle the failure case with the provided error. } } } }
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156
May ’25
NonLiDAR Photogrammetry
Hello! In iOS1.7.5, photogrammetry sessions cannot be performed on iPhones without LiDAR, but I don't think there is much difference in GPU performance between those with and without LiDAR. For example, the chips installed in the iPhone 14 Pro and iPhone 15 are the same A16 Bionic, and I think the GPU performance is also the same. Despite this, photogrammetry can be performed on the iPhone 14 Pro but not on the iPhone 15. Why is this? In fact, we have confirmed that if you transfer images taken with an iPhone 16 without LiDAR to an iPhone 16 Pro and run a photogrammetry session using those images, a 3D model can be generated. Also, will photogrammetry be able to be performed on high-performance iPhones without LiDAR in the future?
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86
Apr ’25