Explore the integration of media technologies within your app. Discuss working with audio, video, camera, and other media functionalities.

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AVAudioMixerNode outputVolume range?
According to the header file the outputVolume properties supported range is 0.0-1.0: /*! @property outputVolume @abstract The mixer's output volume. @discussion This accesses the mixer's output volume (0.0-1.0, inclusive). @property (nonatomic) float outputVolume; However when setting the volume to 2.0 the audio does indeed play louder. Is the header file out of date and if so, what is the supported range for outputVolume? Thanks
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169
Apr ’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. // // ContentView.swift // H265Decoder // // Created by Kohshin Tokunaga on 2025/02/15. // import SwiftUI struct ContentView: View { var body: some View { VStack { Text("H.265 Player (temp.h265)") .font(.headline) VideoPlayerView() .frame(width: 360, height: 640) // Adjust or make it responsive for iOS } .padding() } } #Preview { ContentView() } // // 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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749
May ’25
Image brightness adapts despite exposure lock
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.
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198
Apr ’25
how to enumerate build-in media devices?
Hello, I need to enumerate built-in media devices (cameras, microphones, etc.). For this purpose, I am using the CoreAudio and CoreMediaIO frameworks. According to the table 'Daemon-Safe Frameworks' in Apple’s TN2083, CoreAudio is daemon-safe. However, the documentation does not mention CoreMediaIO. Can CoreMediaIO be used in a daemon? If not, are there any documented alternatives to detect built-in cameras in a daemon (e.g., via device classes in IOKit)? Thank you in advance, Pavel
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175
May ’25
ShazamKit supported for iOS apps that can run on Mac silicon?
I am having issues deploying my iOS app, that uses ShazamKit, to get working on a Mac with Apple silicon. When uploading the archive to App Store Connect I do get ITMS-90863: Macs with Apple silicon support issue - The app links with libraries that aren’t present in macOS: /usr/lib/swift/libswiftShazamKit.dylib Is ShazamKit not supported for iOS apps that can run on Macs with Apple silicon? Or is there something I should fix in my setup / deployment?
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1.2k
Jun ’25
Album parquet files don't include song names
The documentation of the Apple Music Feed API states that the Album object would include songs — a list of songs in the album. As per the doc, this would be an array of object Album.RelatedSong, which would include both an id and nameDefault. Unfortunately, the album parquet files only include the song id and not the name of the song itself. Please advise - is the documentation incorrect or are the recently posted parquet files in error?
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91
May ’25
How to toggle usb device
When I use IOKit/usb/IOUSBLib to toggle build-in camera, I got an ERROR:ret IOReturn -536870210 How can I resolve it? Can I use IOUSBLib to disable or hide build-in camera? My environment: Model Name: MacBook Pro ProductVersion: 15.5 Model Identifier: MacBookPro15,2 Processor Name: Quad-Core Intel Core i5 Processor Speed: 2.4 GHz Number of Processors: 1 // 禁用/启用USB设备 bool toggleUSBDevice(uint16_t vendorID, uint16_t productID, bool enable) { std::cout << (enable ? "Enabling" : "Disabling") << " USB device with VID: 0x" << std::hex << vendorID << ", PID: 0x" << productID << std::endl; // 创建匹配字典查找指定VID/PID的USB设备 CFMutableDictionaryRef matchingDict = IOServiceMatching(kIOUSBDeviceClassName); if (!matchingDict) { std::cerr << "Failed to create USB device matching dictionary." << std::endl; return false; } // 设置VID/PID匹配条件 CFNumberRef vendorIDRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt16Type, &vendorID); CFNumberRef productIDRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt16Type, &productID); CFDictionarySetValue(matchingDict, CFSTR(kUSBVendorID), vendorIDRef); CFDictionarySetValue(matchingDict, CFSTR(kUSBProductID), productIDRef); CFRelease(vendorIDRef); CFRelease(productIDRef); // 获取匹配的设备迭代器 io_iterator_t deviceIterator; if (IOServiceGetMatchingServices(kIOMainPortDefault, matchingDict, &deviceIterator) != KERN_SUCCESS) { std::cerr << "Failed to get USB device iterator." << std::endl; CFRelease(matchingDict); return false; } io_service_t usbDevice; bool result = false; int deviceCount = 0; // 遍历所有匹配的设备 while ((usbDevice = IOIteratorNext(deviceIterator)) != IO_OBJECT_NULL) { deviceCount++; // 获取设备路径 char path[1024]; if (IORegistryEntryGetPath(usbDevice, kIOServicePlane, path) == KERN_SUCCESS) { std::cout << "Found device at path: " << path << std::endl; } // 打开设备 IOCFPlugInInterface** plugInInterface = NULL; IOUSBDeviceInterface** deviceInterface = NULL; SInt32 score; IOReturn ret = IOCreatePlugInInterfaceForService( usbDevice, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plugInInterface, &score); if (ret == kIOReturnSuccess && plugInInterface) { ret = (*plugInInterface)->QueryInterface(plugInInterface, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), (LPVOID*)&deviceInterface); (*plugInInterface)->Release(plugInInterface); } if (ret != kIOReturnSuccess) { std::cerr << "Failed to open USB device interface. Error:" << ret << std::endl; IOObjectRelease(usbDevice); continue; } // 禁用/启用设备 if (enable) { // 启用设备 - 重新配置设备 ret = (*deviceInterface)->USBDeviceReEnumerate(deviceInterface, 0); if (ret == kIOReturnSuccess) { std::cout << "Device enabled successfully." << std::endl; result = true; } else { std::cerr << "Failed to enable device. Error: " << ret << std::endl; } } else { // 禁用设备 - 断开设备连接 ret = (*deviceInterface)->USBDeviceClose(deviceInterface); if (ret == kIOReturnSuccess) { std::cout << "Device disabled successfully." << std::endl; result = true; } else { std::cerr << "Failed to disable device. Error: " << ret << std::endl; } } // 关闭设备接口 (*deviceInterface)->Release(deviceInterface); IOObjectRelease(usbDevice); } IOObjectRelease(deviceIterator); if (deviceCount == 0) { std::cerr << "No device found with specified VID/PID." << std::endl; return false; } return result; }
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233
Jun ’25
TTS Audio Unit Extension: File Write Access in App Group Container Denied Despite Proper Entitlements
I'm developing a TTS Audio Unit Extension that needs to write trace/log files to a shared App Group container. While the main app can successfully create and write files to the container, the extension gets sandbox denied errors despite having proper App Group entitlements configured. Setup: Main App (Flutter) and TTS Audio Unit Extension share the same App Group App Group is properly configured in developer portal and entitlements Main app successfully creates and uses files in the container Container structure shows existing directories (config/, dictionary/) with populated files Both targets have App Group capability enabled and entitlements set Current behavior: Extension can access/read the App Group container Extension can see existing directories and files All write attempts are blocked with "sandbox deny(1) file-write-create" errors Code example: const char* createSharedGroupPathWithComponent(const char* groupId, const char* component) { NSString* groupIdStr = [NSString stringWithUTF8String:groupId]; NSString* componentStr = [NSString stringWithUTF8String:component]; NSURL* url = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:groupIdStr]; NSURL* fullPath = [url URLByAppendingPathComponent:componentStr]; NSError *error = nil; if (![[NSFileManager defaultManager] createDirectoryAtPath:fullPath.path withIntermediateDirectories:YES attributes:nil error:&amp;error]) { NSLog(@"Unable to create directory %@", error.localizedDescription); } return [[fullPath path] UTF8String]; } Error output: Sandbox: simaromur-extension(996) deny(1) file-write-create /private/var/mobile/Containers/Shared/AppGroup/36CAFE9C-BD82-43DD-A962-2B4424E60043/trace Key questions: Are there additional entitlements required for TTS Audio Unit Extensions to write to App Group containers? Is this a known limitation of TTS Audio Unit Extensions? What is the recommended way to handle logging/tracing in TTS Audio Unit Extensions? If writing to App Group containers is not supported, what alternatives are available? Current entitlements: &lt;dict&gt; &lt;key&gt;com.apple.security.application-groups&lt;/key&gt; &lt;array&gt; &lt;string&gt;group.com.&lt;company&gt;.&lt;appname&gt;&lt;/string&gt; &lt;/array&gt; &lt;/dict&gt;
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120
Apr ’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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193
Jun ’25
How to Get Device Orientation in Background (PiP) Mode?
My app is a camera app that supports Picture-in-Picture (PiP) mode. Normally, when the device rotates, I get the device orientation from iOS and use it to rotate the camera feed so that the preview stays correctly aligned. However, when the app enters PiP mode, it is considered to be in the background, and I can no longer receive orientation updates from the system. As a result, I can’t apply rotation corrections to the camera video in PiP mode. Is there any way to retrieve device orientation while the app is in the background (specifically during PiP mode)? Any guidance would be greatly appreciated. Thank you!
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76
May ’25
AudioUnit may experience silent capture issues on iPadOS 18.4.1 or 18.5.
Among the millions of users of our online product, we have identified through data metrics that the silent audio data capture rate on iPadOS 18.4.1 or 18.5 has increased abnormally. However, we are unable to reproduce the issue. Has anyone encountered a similar issue? The parameters we used are as follows: AudioSession: category:AVAudioSessionCategoryPlayAndRecord mode:AVAudioSessionModeDefault option:77 preferredSampleRate:48000.000000 preferredIOBufferDuration:0.010000 AudioUnit format.mFormatID = kAudioFormatLinearPCM; format.mSampleRate = 48000.0; format.mChannelsPerFrame = 2; format.mBitsPerChannel = 16; format.mFramesPerPacket = 1; format.mBytesPerFrame = format.mChannelsPerFrame * 16 / 8; format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket; format.mFormatFlags = kAudioFormatFlagsNativeEndian | kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger; component.componentType = kAudioUnitType_Output; component.componentSubType = kAudioUnitSubType_RemoteIO; component.componentManufacturer = kAudioUnitManufacturer_Apple; component.componentFlags = 0; component.componentFlagsMask = 0;
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152
Jun ’25
Ducking MusicKit output when playing another sound
I am developing an app that uses MusicKit to play music and then I need to have spoken words played to the user, while ducking the audio coming from MusicKit (application music player) the built in Siri voices are not off sufficient quality so I am using an external service to create an mp3 file and then play this back using AVAudioSession Sample code below the problem I am having is that .duckOthers is not ducking the Application Music Player output Is this a bug or am I doing this wrong? // Configure audio session for system-wide ducking try AVAudioSession.sharedInstance().setCategory(.playback, mode: .spokenAudio, options: [.duckOthers, .mixWithOthers]) try AVAudioSession.sharedInstance().setActive(true) // Set the ducking level to maximum try AVAudioSession.sharedInstance().setPreferredIOBufferDuration(0.005) // Create and configure audio player self.audioPlayer = try AVAudioPlayer(data: audioData) self.audioPlayer?.delegate = self self.audioPlayer?.volume = 1.0 // Ensure full volume for speech self.audioPlayer?.prepareToPlay() // Set the audio player's settings for maximum clarity self.audioPlayer?.enableRate = false self.audioPlayer?.pan = 0.0 // Center the audio self.audioPlayer?.play()
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66
Apr ’25
Significant Uptick in AVCaptureSessionWasInterrupted (Reason 4) Leading to Camera Black Screen and AVError Code -11803
In the latest production release of our iOS app (deployed via the App Store), we’ve observed a significant increase in AVCaptureSessionWasInterrupted notifications where the interruption reason has a rawValue of 4. The session does not automatically recover, even after returning from background or deleting/reinstalling the app. An employee ran into this and was able to get a recording. We see the below error when attempting to take photos. "Error Domain=AVFoundationErrorDomain Code=-11803 \"Cannot Record\" UserInfo={AVErrorRecordingFailureDomainKey=3, NSLocalizedDescription=Cannot Record, NSLocalizedRecoverySuggestion=Try recording again.}", } This interruption causes the camera preview to remain black, and any attempt to capture an image results in a failure with the following error: Some questions from our team: What common system conditions or foreground app behaviors can cause .videoDeviceNotAvailableWithMultipleForegroundApps (reason 4) to become persistent? Our teams under is under the impression the interruption reason 4 is mostly associated with iPad and PiP, but neither of these are true in the logs we see. Is manual recovery of the session required? Is there a recommended strategy to detect that the session is unrecoverable and gracefully notify the user or rebuild the session? Is there an instrument(s) in XCode you would recommend when trying to evaluate the increase in reason 4? Best, Ben
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Jun ’25
videoCaptureQueue would make the app crashed when I using IOS 18.4.1
Hi All I have some problem when I using the IOS 18.4.1 I have iphone16 pro and ipad Air, both are updated to IOS 18.4.1 I tried to following sample code. However, when I run the app around 30 seconds to 1 minutes, the application would be crashed When I using another Ipad with IOS 17, it would not have the same problem. https://developer.apple.com/documentation/createml/creating-an-action-classifier-model https://developer.apple.com/documentation/createml/detecting_human_actions_in_a_live_video_feed#overview%29,
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254
May ’25
Apple Music API Library Playlist Images
Hi, I'm sending an API request to: https://api.music.apple.com/v1/me/library/playlists?limit=$limit&offset=$offset To list all of the users library playlists, however the resulting objects do not contain the playlist artwork in the JSON. I've tried adding the extend and include attributes as well but to no avail. A partial example of the response: {"id": PLAYLIST_ID, "type": "library-playlists", "href": "/v1/me/library/playlists/PLAYLIST_ID", "attributes": {"lastModifiedDate": "2024-09-18T20:18:24Z", "canEdit": true, "name": "Afro Party Anthems", "isPublic": false, "description": {"standard": "Definitive African party starters"}, "hasCatalog": false, "dateAdded": "2022-03-10T18:30:56Z", "playParams": {"id": PLAYLIST_ID, "kind": "playlist", "isLibrary": true}}, "relationships": {"catalog": {"href": "/v1/me/library/playlists/PLAYLIST_ID/catalog", "data": []}}} Is there a way to get the artwork URL without sending a request for each playlist? And if not can this be fixed?
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133
Jun ’25
AVAudioMixerNode outputVolume range?
According to the header file the outputVolume properties supported range is 0.0-1.0: /*! @property outputVolume @abstract The mixer's output volume. @discussion This accesses the mixer's output volume (0.0-1.0, inclusive). @property (nonatomic) float outputVolume; However when setting the volume to 2.0 the audio does indeed play louder. Is the header file out of date and if so, what is the supported range for outputVolume? Thanks
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169
Activity
Apr ’25
Apple Device Sync Backup
When using the Apple Devices to sync Apple Music to iPhone where is the Apple Devices backup being written to? Apple Devices->music->sync. Not trying to backup the iPhone via Apple Devices app.
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0
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87
Activity
Jun ’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. // // ContentView.swift // H265Decoder // // Created by Kohshin Tokunaga on 2025/02/15. // import SwiftUI struct ContentView: View { var body: some View { VStack { Text("H.265 Player (temp.h265)") .font(.headline) VideoPlayerView() .frame(width: 360, height: 640) // Adjust or make it responsive for iOS } .padding() } } #Preview { ContentView() } // // 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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2
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749
Activity
May ’25
How to calculate smoothness to replicate CALayerCornerCurve.continuous?
iOS 26 added smoothness to CIRoundedRectangleGenerator, for use with CIFilter.roundedRectangleGenerator. What should the smoothness value be to achieve the same corner curve as CALayerCornerCurve.continuous? Does it need to be calculated based on the extent size, if so, how?
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1
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0
Views
246
Activity
Jun ’25
Image brightness adapts despite exposure lock
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.
Replies
1
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198
Activity
Apr ’25
Regarding the detection of screen orientation (portrait/landscape) in CMSampleBuffer when using ReplayKit for background screen recording
I'm currently using ReplayKit for background screen recording, but I can't determine whether the screen is in landscape mode from the CMSampleBuffer. All other APIs for detecting screen orientation are foreground-based. What should I do?
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0
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91
Activity
Jun ’25
how to enumerate build-in media devices?
Hello, I need to enumerate built-in media devices (cameras, microphones, etc.). For this purpose, I am using the CoreAudio and CoreMediaIO frameworks. According to the table 'Daemon-Safe Frameworks' in Apple’s TN2083, CoreAudio is daemon-safe. However, the documentation does not mention CoreMediaIO. Can CoreMediaIO be used in a daemon? If not, are there any documented alternatives to detect built-in cameras in a daemon (e.g., via device classes in IOKit)? Thank you in advance, Pavel
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0
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0
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175
Activity
May ’25
ShazamKit supported for iOS apps that can run on Mac silicon?
I am having issues deploying my iOS app, that uses ShazamKit, to get working on a Mac with Apple silicon. When uploading the archive to App Store Connect I do get ITMS-90863: Macs with Apple silicon support issue - The app links with libraries that aren’t present in macOS: /usr/lib/swift/libswiftShazamKit.dylib Is ShazamKit not supported for iOS apps that can run on Macs with Apple silicon? Or is there something I should fix in my setup / deployment?
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26
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0
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1.2k
Activity
Jun ’25
Pip custom view in Xcode16, iOS18, does not display when the camera is turned on
I have added some custom views on my pip. These controls disappeared after opening the camera in the Xcode16 environment and iOS 18 system, and it was found that these custom views were not removed and seemed to be obscured. They were displayed normally in the Xcode15.4 environment. I would like to ask how to make my custom views display normally
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0
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0
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94
Activity
Apr ’25
How to show animated album artwork in iOS 26?
I have an app that displays artwork via MPMediaItem.artwork, requesting an image with a specific size. How do I get a media item's MPMediaItemAnimatedArtwork, and how to get the preview image and video to display to the user?
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0
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0
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138
Activity
Jun ’25
Album parquet files don't include song names
The documentation of the Apple Music Feed API states that the Album object would include songs — a list of songs in the album. As per the doc, this would be an array of object Album.RelatedSong, which would include both an id and nameDefault. Unfortunately, the album parquet files only include the song id and not the name of the song itself. Please advise - is the documentation incorrect or are the recently posted parquet files in error?
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0
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0
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91
Activity
May ’25
How to toggle usb device
When I use IOKit/usb/IOUSBLib to toggle build-in camera, I got an ERROR:ret IOReturn -536870210 How can I resolve it? Can I use IOUSBLib to disable or hide build-in camera? My environment: Model Name: MacBook Pro ProductVersion: 15.5 Model Identifier: MacBookPro15,2 Processor Name: Quad-Core Intel Core i5 Processor Speed: 2.4 GHz Number of Processors: 1 // 禁用/启用USB设备 bool toggleUSBDevice(uint16_t vendorID, uint16_t productID, bool enable) { std::cout << (enable ? "Enabling" : "Disabling") << " USB device with VID: 0x" << std::hex << vendorID << ", PID: 0x" << productID << std::endl; // 创建匹配字典查找指定VID/PID的USB设备 CFMutableDictionaryRef matchingDict = IOServiceMatching(kIOUSBDeviceClassName); if (!matchingDict) { std::cerr << "Failed to create USB device matching dictionary." << std::endl; return false; } // 设置VID/PID匹配条件 CFNumberRef vendorIDRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt16Type, &vendorID); CFNumberRef productIDRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt16Type, &productID); CFDictionarySetValue(matchingDict, CFSTR(kUSBVendorID), vendorIDRef); CFDictionarySetValue(matchingDict, CFSTR(kUSBProductID), productIDRef); CFRelease(vendorIDRef); CFRelease(productIDRef); // 获取匹配的设备迭代器 io_iterator_t deviceIterator; if (IOServiceGetMatchingServices(kIOMainPortDefault, matchingDict, &deviceIterator) != KERN_SUCCESS) { std::cerr << "Failed to get USB device iterator." << std::endl; CFRelease(matchingDict); return false; } io_service_t usbDevice; bool result = false; int deviceCount = 0; // 遍历所有匹配的设备 while ((usbDevice = IOIteratorNext(deviceIterator)) != IO_OBJECT_NULL) { deviceCount++; // 获取设备路径 char path[1024]; if (IORegistryEntryGetPath(usbDevice, kIOServicePlane, path) == KERN_SUCCESS) { std::cout << "Found device at path: " << path << std::endl; } // 打开设备 IOCFPlugInInterface** plugInInterface = NULL; IOUSBDeviceInterface** deviceInterface = NULL; SInt32 score; IOReturn ret = IOCreatePlugInInterfaceForService( usbDevice, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plugInInterface, &score); if (ret == kIOReturnSuccess && plugInInterface) { ret = (*plugInInterface)->QueryInterface(plugInInterface, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), (LPVOID*)&deviceInterface); (*plugInInterface)->Release(plugInInterface); } if (ret != kIOReturnSuccess) { std::cerr << "Failed to open USB device interface. Error:" << ret << std::endl; IOObjectRelease(usbDevice); continue; } // 禁用/启用设备 if (enable) { // 启用设备 - 重新配置设备 ret = (*deviceInterface)->USBDeviceReEnumerate(deviceInterface, 0); if (ret == kIOReturnSuccess) { std::cout << "Device enabled successfully." << std::endl; result = true; } else { std::cerr << "Failed to enable device. Error: " << ret << std::endl; } } else { // 禁用设备 - 断开设备连接 ret = (*deviceInterface)->USBDeviceClose(deviceInterface); if (ret == kIOReturnSuccess) { std::cout << "Device disabled successfully." << std::endl; result = true; } else { std::cerr << "Failed to disable device. Error: " << ret << std::endl; } } // 关闭设备接口 (*deviceInterface)->Release(deviceInterface); IOObjectRelease(usbDevice); } IOObjectRelease(deviceIterator); if (deviceCount == 0) { std::cerr << "No device found with specified VID/PID." << std::endl; return false; } return result; }
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233
Activity
Jun ’25
TTS Audio Unit Extension: File Write Access in App Group Container Denied Despite Proper Entitlements
I'm developing a TTS Audio Unit Extension that needs to write trace/log files to a shared App Group container. While the main app can successfully create and write files to the container, the extension gets sandbox denied errors despite having proper App Group entitlements configured. Setup: Main App (Flutter) and TTS Audio Unit Extension share the same App Group App Group is properly configured in developer portal and entitlements Main app successfully creates and uses files in the container Container structure shows existing directories (config/, dictionary/) with populated files Both targets have App Group capability enabled and entitlements set Current behavior: Extension can access/read the App Group container Extension can see existing directories and files All write attempts are blocked with "sandbox deny(1) file-write-create" errors Code example: const char* createSharedGroupPathWithComponent(const char* groupId, const char* component) { NSString* groupIdStr = [NSString stringWithUTF8String:groupId]; NSString* componentStr = [NSString stringWithUTF8String:component]; NSURL* url = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:groupIdStr]; NSURL* fullPath = [url URLByAppendingPathComponent:componentStr]; NSError *error = nil; if (![[NSFileManager defaultManager] createDirectoryAtPath:fullPath.path withIntermediateDirectories:YES attributes:nil error:&amp;error]) { NSLog(@"Unable to create directory %@", error.localizedDescription); } return [[fullPath path] UTF8String]; } Error output: Sandbox: simaromur-extension(996) deny(1) file-write-create /private/var/mobile/Containers/Shared/AppGroup/36CAFE9C-BD82-43DD-A962-2B4424E60043/trace Key questions: Are there additional entitlements required for TTS Audio Unit Extensions to write to App Group containers? Is this a known limitation of TTS Audio Unit Extensions? What is the recommended way to handle logging/tracing in TTS Audio Unit Extensions? If writing to App Group containers is not supported, what alternatives are available? Current entitlements: &lt;dict&gt; &lt;key&gt;com.apple.security.application-groups&lt;/key&gt; &lt;array&gt; &lt;string&gt;group.com.&lt;company&gt;.&lt;appname&gt;&lt;/string&gt; &lt;/array&gt; &lt;/dict&gt;
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0
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120
Activity
Apr ’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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0
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193
Activity
Jun ’25
How to Get Device Orientation in Background (PiP) Mode?
My app is a camera app that supports Picture-in-Picture (PiP) mode. Normally, when the device rotates, I get the device orientation from iOS and use it to rotate the camera feed so that the preview stays correctly aligned. However, when the app enters PiP mode, it is considered to be in the background, and I can no longer receive orientation updates from the system. As a result, I can’t apply rotation corrections to the camera video in PiP mode. Is there any way to retrieve device orientation while the app is in the background (specifically during PiP mode)? Any guidance would be greatly appreciated. Thank you!
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0
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76
Activity
May ’25
AudioUnit may experience silent capture issues on iPadOS 18.4.1 or 18.5.
Among the millions of users of our online product, we have identified through data metrics that the silent audio data capture rate on iPadOS 18.4.1 or 18.5 has increased abnormally. However, we are unable to reproduce the issue. Has anyone encountered a similar issue? The parameters we used are as follows: AudioSession: category:AVAudioSessionCategoryPlayAndRecord mode:AVAudioSessionModeDefault option:77 preferredSampleRate:48000.000000 preferredIOBufferDuration:0.010000 AudioUnit format.mFormatID = kAudioFormatLinearPCM; format.mSampleRate = 48000.0; format.mChannelsPerFrame = 2; format.mBitsPerChannel = 16; format.mFramesPerPacket = 1; format.mBytesPerFrame = format.mChannelsPerFrame * 16 / 8; format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket; format.mFormatFlags = kAudioFormatFlagsNativeEndian | kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger; component.componentType = kAudioUnitType_Output; component.componentSubType = kAudioUnitSubType_RemoteIO; component.componentManufacturer = kAudioUnitManufacturer_Apple; component.componentFlags = 0; component.componentFlagsMask = 0;
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0
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152
Activity
Jun ’25
Ducking MusicKit output when playing another sound
I am developing an app that uses MusicKit to play music and then I need to have spoken words played to the user, while ducking the audio coming from MusicKit (application music player) the built in Siri voices are not off sufficient quality so I am using an external service to create an mp3 file and then play this back using AVAudioSession Sample code below the problem I am having is that .duckOthers is not ducking the Application Music Player output Is this a bug or am I doing this wrong? // Configure audio session for system-wide ducking try AVAudioSession.sharedInstance().setCategory(.playback, mode: .spokenAudio, options: [.duckOthers, .mixWithOthers]) try AVAudioSession.sharedInstance().setActive(true) // Set the ducking level to maximum try AVAudioSession.sharedInstance().setPreferredIOBufferDuration(0.005) // Create and configure audio player self.audioPlayer = try AVAudioPlayer(data: audioData) self.audioPlayer?.delegate = self self.audioPlayer?.volume = 1.0 // Ensure full volume for speech self.audioPlayer?.prepareToPlay() // Set the audio player's settings for maximum clarity self.audioPlayer?.enableRate = false self.audioPlayer?.pan = 0.0 // Center the audio self.audioPlayer?.play()
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66
Activity
Apr ’25
Significant Uptick in AVCaptureSessionWasInterrupted (Reason 4) Leading to Camera Black Screen and AVError Code -11803
In the latest production release of our iOS app (deployed via the App Store), we’ve observed a significant increase in AVCaptureSessionWasInterrupted notifications where the interruption reason has a rawValue of 4. The session does not automatically recover, even after returning from background or deleting/reinstalling the app. An employee ran into this and was able to get a recording. We see the below error when attempting to take photos. "Error Domain=AVFoundationErrorDomain Code=-11803 \"Cannot Record\" UserInfo={AVErrorRecordingFailureDomainKey=3, NSLocalizedDescription=Cannot Record, NSLocalizedRecoverySuggestion=Try recording again.}", } This interruption causes the camera preview to remain black, and any attempt to capture an image results in a failure with the following error: Some questions from our team: What common system conditions or foreground app behaviors can cause .videoDeviceNotAvailableWithMultipleForegroundApps (reason 4) to become persistent? Our teams under is under the impression the interruption reason 4 is mostly associated with iPad and PiP, but neither of these are true in the logs we see. Is manual recovery of the session required? Is there a recommended strategy to detect that the session is unrecoverable and gracefully notify the user or rebuild the session? Is there an instrument(s) in XCode you would recommend when trying to evaluate the increase in reason 4? Best, Ben
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3
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17
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632
Activity
Jun ’25
videoCaptureQueue would make the app crashed when I using IOS 18.4.1
Hi All I have some problem when I using the IOS 18.4.1 I have iphone16 pro and ipad Air, both are updated to IOS 18.4.1 I tried to following sample code. However, when I run the app around 30 seconds to 1 minutes, the application would be crashed When I using another Ipad with IOS 17, it would not have the same problem. https://developer.apple.com/documentation/createml/creating-an-action-classifier-model https://developer.apple.com/documentation/createml/detecting_human_actions_in_a_live_video_feed#overview%29,
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6
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254
Activity
May ’25
Apple Music API Library Playlist Images
Hi, I'm sending an API request to: https://api.music.apple.com/v1/me/library/playlists?limit=$limit&offset=$offset To list all of the users library playlists, however the resulting objects do not contain the playlist artwork in the JSON. I've tried adding the extend and include attributes as well but to no avail. A partial example of the response: {"id": PLAYLIST_ID, "type": "library-playlists", "href": "/v1/me/library/playlists/PLAYLIST_ID", "attributes": {"lastModifiedDate": "2024-09-18T20:18:24Z", "canEdit": true, "name": "Afro Party Anthems", "isPublic": false, "description": {"standard": "Definitive African party starters"}, "hasCatalog": false, "dateAdded": "2022-03-10T18:30:56Z", "playParams": {"id": PLAYLIST_ID, "kind": "playlist", "isLibrary": true}}, "relationships": {"catalog": {"href": "/v1/me/library/playlists/PLAYLIST_ID/catalog", "data": []}}} Is there a way to get the artwork URL without sending a request for each playlist? And if not can this be fixed?
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0
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1
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133
Activity
Jun ’25