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

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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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203
Jun ’25
macOS sample for AVAudioEngine recording with playthrough
Hi, I'm still stuck getting a basic record-with-playthrouh pipeline to work. Has anyone a sample of setting up a AVAudioEngine pipeline for recording with playthrough? Plkaythrough works with AVPlayerNode as input but not with any microphone input. The docs mention the "enabled state" of the outputNode of the engine without explaining the concept, i.e. how to enable an output. When the engine renders to and from an audio device, the AVAudioSession category and the availability of hardware determines whether an app performs output. Check the output node’s output format (specifically, the hardware format) for a nonzero sample rate and channel count to see if output is in an enabled state. Well, in my setup the output is NOT enabled, and any attempt to switch (e.g. audioEngine.outputNode.auAudioUnit.setDeviceID(deviceID) )/ attach a dedicated device / ... results in exceptions / errors
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316
Oct ’25
SBS and OU ViewPacking
SBS ViewPacking add a half a frame to the opposite eye. Meaning if you look all the way right you can see an extra half frame with left eye and vice versa. OU doesn't work at all, the preview just doesn't show a thumbnail and the video doesn't play. Any hints on how to fix this? I submitted a bug report but haven't heard anything.
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315
Oct ’25
Does HEVC VideoToolbox support temporal layering of streams with B-frames?
context:Explore low-latency video encoding with VideoToolbox https://developer.apple.com/videos/play/wwdc2021/10158/ I see above post said HEVC VideoToolbox can support SVC, temporal layering of streams in low-latency mode with all P frames. my question is that Does HEVC VideoToolbox support temporal layering of streams with B-frames ?? thanks
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221
Oct ’25
Memory leak AVAudioPlayer
Let's consider the following code. I've created an actor that loads a list of .mp3 files from a Bundle and then makes it available for audio reproduction. Unfortunately, I'm experiencing a memory leak. At the play method. player.play() From Instruments I get _malloc_type_malloc_outlined libsystem_malloc.dylib start_wqthread libsystem_pthread.dylib private actor AudioActor { enum Failure: Error { case soundsNotLoaded([AudioPlayerClient.Sound: Error]) } enum Player { case music(AVAudioPlayer) } var players: [Sound: Player] = [:] let bundles: [Bundle] init(bundles: UncheckedSendable<[Bundle]>) { self.bundles = bundles.wrappedValue } func load(sounds: [Sound]) throws { try AVAudioSession.sharedInstance().setActive(true, options: []) var errors: [Sound: Error] = [:] for sound in sounds { guard let url = bundle.url(forResource: sound.name, withExtension: "mp3") else { continue } do { self.players[sound] = try .music(AVAudioPlayer(contentsOf: url)) } catch { errors[sound] = error } } guard errors.isEmpty else { throw Failure.soundsNotLoaded(errors) } } func play(sound: Sound, loops: Int?) throws { guard let player = self.players[sound] else { return } switch player { case let .music(player): player.numberOfLoops = loops ?? -1 player.play() } } func stop(sound: Sound) throws { guard let player = self.players[sound] else { throw Failure.soundsNotLoaded([:]) } switch player { case let .music(player): player.stop() } } }
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132
Mar ’25
macOS Tahoe: Can't setup AVAudioEngine with playthrough
Hi, I'm trying to setup a AVAudioEngine for USB Audio recording and monitoring playthrough. As soon as I try to setup playthough I get an error in the console: AVAEInternal.h:83 required condition is false: [AVAudioEngineGraph.mm:1361:Initialize: (IsFormatSampleRateAndChannelCountValid(outputHWFormat))] Any ideas how to fix it? // Input-Device setzen try? setupInputDevice(deviceID: inputDevice) let input = audioEngine.inputNode // Stereo-Format erzwingen let inputHWFormat = input.inputFormat(forBus: 0) let stereoFormat = AVAudioFormat(commonFormat: inputHWFormat.commonFormat, sampleRate: inputHWFormat.sampleRate, channels: 2, interleaved: inputHWFormat.isInterleaved) guard let format = stereoFormat else { throw AudioError.deviceSetupFailed(-1) } print("Input format: \(inputHWFormat)") print("Forced stereo format: \(format)") audioEngine.attach(monitorMixer) audioEngine.connect(input, to: monitorMixer, format: format) // MonitorMixer -> MainMixer (Output) // Problem here, format: format also breaks. audioEngine.connect(monitorMixer, to: audioEngine.mainMixerNode, format: nil)
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194
Oct ’25
[AVFCore] IOS 26.0 EXC_BAD_ACCESS from _customCompositorShouldCancelPendingFrames
Hi, I'm working an a video editing software that lets you composite and export videos. I use a custom compositor to apply my effects etc. In my crash dashboard, I am seeing a report of an EXC_BAD_ACCESS crash from objc_msgSend. Below is the stacktrace. libobjc.A.dylib objc_msgSend libdispatch.dylib _dispatch_sync_invoke_and_complete_recurse libdispatch.dylib _dispatch_sync_f_slow [symbolication failed] libdispatch.dylib _dispatch_client_callout libdispatch.dylib _dispatch_lane_barrier_sync_invoke_and_complete AVFCore -[AVCustomVideoCompositorSession(AVCustomVideoCompositorSession_FigCallbackHandling) _customCompositorShouldCancelPendingFrames] AVFCore _customCompositorShouldCancelPendingFramesCallback MediaToolbox remoteVideoCompositor_HandleVideoCompositorClientMessage CoreMedia __figXPCConnection_CallClientMessageHandlers_block_invoke libdispatch.dylib _dispatch_call_block_and_release libdispatch.dylib _dispatch_client_callout libdispatch.dylib _dispatch_lane_serial_drain libdispatch.dylib _dispatch_lane_invoke libdispatch.dylib _dispatch_root_queue_drain_deferred_wlh libdispatch.dylib _dispatch_workloop_worker_thread libsystem_pthread.dylib _pthread_wqthread libsystem_pthread.dylib start_wqthread What stood out to me is that this is only being reported from IOS 26.0+ devices. A part of the stacktrace failed to be symbolicated [symbolication failed]. I'm 90% confident that this is Apple code, not my app's code. I cannot reproduce this locally. Is this a known issue? What are the possible root-causes, and how can I verify/eliminate them? Thanks,
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212
Oct ’25
AVPlayerView with .inline controlsStyle macOS 26
My audio app shows a control bar at the bottom of the window. The controls show nicely, but there is a black "slab" appearing behind the inline controls, the same size as the playerView. Setting the player view background color does nothing: playerView.wantsLayer = true playerView.layer?.backgroundColor = NSColor.clear.cgColor How can I clear the background? If I use .floating controlsStyle, I don't get the background "slab".
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162
Oct ’25
How to record voice, auto-transcribe, translate (auto-detect input language), and play back translated audio on same device in iOS Swift?
Hi everyone 👋 I’m building an iOS app in Swift where I want to do the following: Record the user’s voice Transcribe the spoken sentence (speech-to-text) Auto-detect the spoken language Translate it to another language selected by the user (e.g., English → Spanish or Hindi → English) Speak back (text-to-speech) the translated text on the same device Is this possible to record via phone mic and play the transcribe voice into headphone's audio?
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265
Oct ’25
Intermittent Memory Leak Indicated in Simulator When Using AVAudioEngine with mainMixerNode Only
Hello, I'm observing an intermittent memory leak being reported in the iOS Simulator when initializing and starting an AVAudioEngine. Even with minimal setup—just attaching a single AVAudioPlayerNode and connecting it to the mainMixerNode—Xcode's memory diagnostics and Instruments sometimes flag a leak. Here is a simplified version of the code I'm using: // This function is called when the user taps a button in the view controller: #import "ViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; } - (IBAction)myButtonAction:(id)sender { NSLog(@"Test"); soundCreate(); } @end // media.m static AVAudioEngine *audioEngine = nil; void soundCreate(void) { if (audioEngine != nil) return; [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryAmbient error:nil]; [[AVAudioSession sharedInstance] setActive:YES error:nil]; audioEngine = [[AVAudioEngine alloc] init]; AVAudioPlayerNode* playerNode = [[AVAudioPlayerNode alloc] init]; [audioEngine attachNode:playerNode]; [audioEngine connect:playerNode to:(AVAudioNode *)[audioEngine mainMixerNode] format:nil]; [audioEngine startAndReturnError:nil]; } In the memory leak report, the following call stack is repeated, seemingly in a loop: ListenerMap::InsertEvent(XAudioUnitEvent const&, ListenerBinding*) AudioToolboxCore ListenerMap::AddParameter(AUListener*, void*, XAudioUnitEvent const&) AudioToolboxCore AUListenerAddParameter AudioToolboxCore addOrRemoveParameterListeners(OpaqueAudioComponentInstance*, AUListenerBase*, AUParameterTree*, bool) AudioToolboxCore 0x180178ddf
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125
Apr ’25
Broadcast UploadExtension Stop data transmission
Currently, I am using the Broadcast UploadExtension function to obtain samplebuffer data through APP Group and IPC (based on the local Unix Domain Socket) The screen recording data transmission method of the domain socket is transmitted to the APP. However, when the APP goes back to the background to view videos in the album or other audio and video, the data transmission stops and the APP cannot obtain the screen recording data. I would like to ask how to solve this problem. I suspect that the system has suspended the extended screen recording
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141
Oct ’25
iOS AVPlayer Subtitles / Captions
As of iOS 18, as far as I can tell, it appears there's still no AVPlayer options that allow users to toggle the caption / subtitle track on and off. Does anyone know of a way to do this with AVPlayer or with SwiftUI's VideoPlayer? The following code reproduces this issue. It can be pasted into an app playground. This is a random video and a random vtt file I found on the internet. import SwiftUI import AVKit import UIKit struct ContentView: View { private let video = URL(string: "https://server15700.contentdm.oclc.org/dmwebservices/index.php?q=dmGetStreamingFile/p15700coll2/15.mp4/byte/json")! private let captions = URL(string: "https://gist.githubusercontent.com/samdutton/ca37f3adaf4e23679957b8083e061177/raw/e19399fbccbc069a2af4266e5120ae6bad62699a/sample.vtt")! @State private var player: AVPlayer? var body: some View { VStack { VideoPlayerView(player: player) .frame(maxWidth: .infinity, maxHeight: 200) } .task { // Captions won't work for some reason player = try? await loadPlayer(video: video, captions: captions) } } } private struct VideoPlayerView: UIViewControllerRepresentable { let player: AVPlayer? func makeUIViewController(context: Context) -> AVPlayerViewController { let controller = AVPlayerViewController() controller.player = player controller.modalPresentationStyle = .overFullScreen return controller } func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) { uiViewController.player = player } } private func loadPlayer(video: URL, captions: URL?) async throws -> AVPlayer { let videoAsset = AVURLAsset(url: video) let videoPlusSubtitles = AVMutableComposition() try await videoPlusSubtitles.add(videoAsset, withMediaType: .video) try await videoPlusSubtitles.add(videoAsset, withMediaType: .audio) if let captions { let captionAsset = AVURLAsset(url: captions) // Must add as .text. .closedCaption and .subtitle don't work? try await videoPlusSubtitles.add(captionAsset, withMediaType: .text) } return await AVPlayer(playerItem: AVPlayerItem(asset: videoPlusSubtitles)) } private extension AVMutableComposition { func add(_ asset: AVAsset, withMediaType mediaType: AVMediaType) async throws { let duration = try await asset.load(.duration) try await asset.loadTracks(withMediaType: mediaType).first.map { track in let newTrack = self.addMutableTrack(withMediaType: mediaType, preferredTrackID: kCMPersistentTrackID_Invalid) let range = CMTimeRangeMake(start: .zero, duration: duration) try newTrack?.insertTimeRange(range, of: track, at: .zero) } } }
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113
Apr ’25
Apple Music treats asian artists with romanized names as two different names
Hello, I'm trying to write a shortcut using Toolbox Pro that gets triggered by an accessibility trigger and then favorites the currently playing song. It's working pretty well, but I noticed that for some artists, especially asian ones, it simply doesn't work. While debugging, I noticed that the tool uses the same song ID, artist ID, everything as it should to search for the song and favorite it. However, I noticed that Apple Music treats artists with romanized names as two separate artists! https://music.apple.com/br/artist/王菲/41760704 https://music.apple.com/br/artist/faye-wong/41760704?l=en-GB You can see that the ID is the same (41760704). It seems that, when I search for the artist, the first artist (王菲) returns, so that when I open URLs on the web for the artist I can see a star next to the song name, meaning that it got a like. However, the romanized artist (faye-wong) doesn't have a like on the same song. This is very weird, right?
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127
Oct ’25
AsyncPublisher for AVPlayerItem not working
Hello, I'm trying to subscribe to AVPlayerItem status updates using Combine and it's bridge to Swift Concurrency – .values. This is my sample code. struct ContentView: View { @State var player: AVPlayer? @State var loaded = false var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let publisher = player.publisher(for: \.status) for await status in publisher.values { print(status.rawValue) if status == .readyToPlay { loaded = true break } } print("we are out") } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } After I click on the "load" button it prints out 0 (as the initial status of .unknown) and nothing after – even when the video is fully loaded. At the same time this works as expected (loading status is set to true): struct ContentView: View { @State var player: AVPlayer? @State var loaded = false @State var cancellable: AnyCancellable? var body: some View { VStack { if let player { Text("loading status: \(loaded)") Spacer() VideoPlayer(player: player) Button("Load") { Task { let item = AVPlayerItem( url: URL(string: "https://sample-videos.com/video321/mp4/360/big_buck_bunny_360p_5mb.mp4")! ) player.replaceCurrentItem(with: item) let stream = AsyncStream { continuation in cancellable = item.publisher(for: \.status) .sink { if $0 == .readyToPlay { continuation.yield($0) continuation.finish() } } } for await _ in stream { loaded = true cancellable?.cancel() cancellable = nil break } } } } else { Text("No video selected") } } .task { player = AVPlayer() } } } Is this a bug or something?
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173
Jun ’25
On iOS26, in our video playback app(use AVPlayer), the sound and video are out of sync when playing after seeking.
Our app plays TS files on an iPhone. The app fragments the TS files, creates an M3U8 playlist, converts them to HLS(HTTP Live Streaming), and then uses AVPlayer to play the video content. On a device running iOS 26, after starting playback and seeking, restarting playback causes the video and audio to be out of sync (by about 2-3 seconds depending on the situation). This also occurs on iPadOS/macOS 26. This issue was not observed prior to iOS 18. We are trying to fix this issue on the app side, but we have the following questions: The behavior of AVPlayer is different between iOS 26 and previous versions. Has there been any change that could be considered? Or is it a bug? We tried pausing before seeking, but it didn’t seem to have any effect. Are there any APIs or workarounds that can improve this? We would appreciate it if you could tell us any other helpful documents or URLs.
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369
Sep ’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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87
Apr ’25
Destroy MIDIUMPMutableEndpoint again?
Is there a way to destroy MIDIUMPMutableEndpoint again? In my app, the user has a setting to enable and disable MIDI 2.0. If MIDI 2.0 should not be supported (or if iOS version < 18), it creates a virtual destination and a virtual source. And if MIDI 2.0 should be enabled, it instead creates a MIDIUMPMutableEndpoint, which itself creates the virtual destination and source automatically. So here is my problem: I didn't find any way to destroy the MIDIUMPMutableEndpoint again. There is a method to disable it (setEnabled:NO), but that doesn't destroy or hide the virtual destination and source. So when the user turns MIDI 2.0 support off, I will have two virtual destinations and sources, and cannot get rid of the 2.0 ones. What is the correct way to get rid of the MIDIUMPMutableEndpoint once it is created?
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144
Sep ’25