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CVPixelBufferCreate EXC_BAD_ACCESS
I am doing something similar to this post Within an AVCaptureDataOutputSynchronizerDelegate method, I create a pixelBuffer using CVPixelBufferCreate with the following attributes: kCVPixelBufferIOSurfacePropertiesKey as String: true, kCVPixelBufferIOSurfaceOpenGLESTextureCompatibilityKey as String: true When I copy the data from the vImagePixelBuffer "rotatedImageBuffer", I get the following error: Thread 10: EXC_BAD_ACCESS (code=1, address=0x14caa8000) I get the same error with memcpy and data.copyBytes (not running them at the same time obviously). If I use CVPixelBufferCreateWithBytes, I do not get this error. However, CVPixelBufferCreateWithBytes does not let you include attributes (see linked post above). I am using vImage because I need the original CVPixelBuffer from the camera output and a rotated version with a different color scheme. // Copy to pixel buffer let attributes: NSDictionary = [ true : kCVPixelBufferIOSurfacePropertiesKey, true : kCVPixelBufferIOSurfaceOpenGLESTextureCompatibilityKey, ] var colorBuffer: CVPixelBuffer? let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(rotatedImageBuffer.width), Int(rotatedImageBuffer.height), kCVPixelFormatType_32BGRA, attributes, &colorBuffer) //let status = CVPixelBufferCreateWithBytes(kCFAllocatorDefault, Int(rotatedImageBuffer.width), Int(rotatedImageBuffer.height), kCVPixelFormatType_32BGRA, rotatedImageBuffer.data, rotatedImageBuffer.rowBytes, nil, nil, attributes as CFDictionary, &colorBuffer) // does NOT produce error, but also does not have attributes guard status == kCVReturnSuccess, let colorBuffer = colorBuffer else { print("Failed to create buffer") return } let lockFlags = CVPixelBufferLockFlags(rawValue: 0) guard kCVReturnSuccess == CVPixelBufferLockBaseAddress(colorBuffer, lockFlags) else { print("Failed to lock base address") return } let colorBufferMemory = CVPixelBufferGetBaseAddress(colorBuffer)! let data = Data(bytes: rotatedImageBuffer.data, count: rotatedImageBuffer.rowBytes * Int(rotatedImageBuffer.height)) data.copyBytes(to: colorBufferMemory.assumingMemoryBound(to: UInt8.self), count: data.count) // Fails here //memcpy(colorBufferMemory, rotatedImageBuffer.data, rotatedImageBuffer.rowBytes * Int(rotatedImageBuffer.height)) // Also produces the same error CVPixelBufferUnlockBaseAddress(colorBuffer, lockFlags)
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318
Apr ’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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130
Apr ’25
Crackling/Popping sound when using AVAudioUnitTimePitch
I have a simple AVAudioEngine graph as follows: AVAudioPlayerNode -> AVAudioUnitEQ -> AVAudioUnitTimePitch -> AVAudioUnitReverb -> Main mixer node of AVAudioEngine. I noticed that whenever I have AVAudioUnitTimePitch or AVAudioUnitVarispeed in the graph, I noticed a very distinct crackling/popping sound in my Airpods Pro 2 when starting up the engine and playing the AVAudioPlayerNode and unable to find the reason why this is happening. When I remove the node, the crackling completely goes away. How do I fix this problem since i need the user to be able to control the pitch and rate of the audio during playback. import AVKit @Observable @MainActor class AudioEngineManager { nonisolated private let engine = AVAudioEngine() private let playerNode = AVAudioPlayerNode() private let reverb = AVAudioUnitReverb() private let pitch = AVAudioUnitTimePitch() private let eq = AVAudioUnitEQ(numberOfBands: 10) private var audioFile: AVAudioFile? private var fadePlayPauseTask: Task<Void, Error>? private var playPauseCurrentFadeTime: Double = 0 init() { setupAudioEngine() } private func setupAudioEngine() { guard let url = Bundle.main.url(forResource: "Song name goes here", withExtension: "mp3") else { print("Audio file not found") return } do { audioFile = try AVAudioFile(forReading: url) } catch { print("Failed to load audio file: \(error)") return } reverb.loadFactoryPreset(.mediumHall) reverb.wetDryMix = 50 pitch.pitch = 0 // Increase pitch by 500 cents (5 semitones) engine.attach(playerNode) engine.attach(pitch) engine.attach(reverb) engine.attach(eq) // Connect: player -> pitch -> reverb -> output engine.connect(playerNode, to: eq, format: audioFile?.processingFormat) engine.connect(eq, to: pitch, format: audioFile?.processingFormat) engine.connect(pitch, to: reverb, format: audioFile?.processingFormat) engine.connect(reverb, to: engine.mainMixerNode, format: audioFile?.processingFormat) } func prepare() { guard let audioFile else { return } playerNode.scheduleFile(audioFile, at: nil) } func play() { DispatchQueue.global().async { [weak self] in guard let self else { return } engine.prepare() try? engine.start() DispatchQueue.main.async { [weak self] in guard let self else { return } playerNode.play() fadePlayPauseTask?.cancel() playPauseCurrentFadeTime = 0 fadePlayPauseTask = Task { [weak self] in guard let self else { return } while true { let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: true) // Ramp up volume until 1 is reached if volume >= 1 { break } engine.mainMixerNode.outputVolume = volume try await Task.sleep(for: .milliseconds(10)) playPauseCurrentFadeTime += 0.01 } engine.mainMixerNode.outputVolume = 1 } } } } func pause() { fadePlayPauseTask?.cancel() playPauseCurrentFadeTime = 0 fadePlayPauseTask = Task { [weak self] in guard let self else { return } while true { let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: false) // Ramp down volume until 0 is reached if volume <= 0 { break } engine.mainMixerNode.outputVolume = volume try await Task.sleep(for: .milliseconds(10)) playPauseCurrentFadeTime += 0.01 } engine.mainMixerNode.outputVolume = 0 playerNode.pause() // Shut down engine once ramp down completes DispatchQueue.global().async { [weak self] in guard let self else { return } engine.pause() } } } private func updateVolume(for x: Double, rising: Bool) -> Float { if rising { // Fade in return Float(pow(x, 2) * (3.0 - 2.0 * (x))) } else { // Fade out return Float(1 - (pow(x, 2) * (3.0 - 2.0 * (x)))) } } func setPitch(_ value: Float) { pitch.pitch = value } func setReverbMix(_ value: Float) { reverb.wetDryMix = value } } struct ContentView: View { @State private var audioManager = AudioEngineManager() @State private var pitch: Float = 0 @State private var reverb: Float = 0 var body: some View { VStack(spacing: 20) { Text("🎵 Audio Player with Reverb & Pitch") .font(.title2) HStack { Button("Prepare") { audioManager.prepare() } Button("Play") { audioManager.play() } .padding() .background(Color.green) .foregroundColor(.white) .cornerRadius(10) Button("Pause") { audioManager.pause() } .padding() .background(Color.red) .foregroundColor(.white) .cornerRadius(10) } VStack { Text("Pitch: \(Int(pitch)) cents") Slider(value: $pitch, in: -2400...2400, step: 100) { _ in audioManager.setPitch(pitch) } } VStack { Text("Reverb Mix: \(Int(reverb))%") Slider(value: $reverb, in: 0...100, step: 1) { _ in audioManager.setReverbMix(reverb) } } } .padding() } }
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285
Apr ’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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117
Apr ’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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119
Apr ’25
CoreAudio server plugin gaining write access with SystemConfiguration.framework functions
Hi, our CourAudio server plugin utilizes the SystemConfiguration.framework to store and restore specific shared system wide settings. While our application can authenticate to utilize the SystemConfiguration.framework to gain write access to the shared configuration settings the CoreAudio server plugin obviously can't have any user interaction and therefor does not authenticate. Is it possible to authenticate the CoreAudio server plugin to gain write permissions? Are there any entitlements or other means that would allow this? Thanks!
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Apr ’25
MusicKit - Skipping Forwards or Backwards does not update
Hello everyone, I am working on an app that allows you to review your own music using Apple Music. Currently I am running into an issue with the skipping forwards and backwards outside of the app. How it should work: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song on an album should play and the information should change to reflect that in the app. If you play a song in Apple Music, you can see a Now Playing view in the lock screen. When you skip forward or backwards, it will do either action and it would reflect that when you see a little frequency icon on artwork image of a song. What it's doing: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song is reflected outside of the app, but not in the app. When skipping a song outside of the app, it works correctly to head to the next song. But when I return to the app, it is not reflected NOTE: I am not using MusicKit variables such as Track, Album to display the songs. Since I want to grab the songs and review them I need a rating so I created my own that grabs the MusicItemID, name, artist(s), etc. NOTE: I am using ApplicationMusicPlayer.shared Is there a way to get the song to reflect in my app? (If its easier, a simple example of it would be nice. No need to create an entire xprod file)
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101
Apr ’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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93
Apr ’25
Apple News Publisher: How To Successfully Apply
Hi there, Can anyone tell me how to possibly get approved as an Apple News Publisher in 2025? We attempted in 2024, but received this message from Apple support: "Thank you for your interest in Apple News. At this time, we're not accepting new applications." When I inquired further, I got this second response: "Apple News is no longer accepting unsolicited applications. To learn more about Apple News requirements, visit the Apple News support page. If you have any feedback, please use this form to send us your comments. Keep in mind that while we read all feedback, we are unable to respond to each submission individually." My questions are: Is this still the case? (Especially when you are a legit local news outlet) Is there a link to apply as a news publisher? I don't seem to have that option at all. Thanks for any feedback.
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137
Apr ’25
AVAssetWriterInputTaggedPixelBufferGroupAdaptor Hanging With Tagged Buffers
We've successfully implemented an AVAssetWriter to produce HLS streams (all code is Objective-C++ for interop with existing codebase) but are struggling to extend the operations to use tagged buffers. We're starting to wonder if the tagged buffers required for an MV-HEVC signal are fully supported when producing HLS segments in a live-stream setting. We generate a live stream of data using something like: UTType *t = [UTType typeWithIdentifier:AVFileTypeMPEG4]; m_writter = [[AVAssetWriter alloc] initWithContentType:t]; // - videoHint describes HEVC and width/height // - m_videoConfig includes compression settings and, when using MV-HEVC, // the correct keys are added (i.e. kVTCompressionPropertyKey_MVHEVCVideoLayerIDs) // The app was throwing an exception without these which was // useful to know when we got the configuration right. m_video = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:m_videoConfig sourceFormatHint:videoHint]; For either path we're producing CVPixelBufferRefs that contain the raw pixel information (i.e. 32BGRA) so we use an adapter to make that as simple as possible. If we use a single view and a AVAssetWriterInputPixelBufferAdaptor things work out very well. We produce segments and the delegate is called. However, if we use the AVAssetWriterInputTaggedPixelBufferGroupAdaptor as exampled in the SideBySideToMVHEVC demo project, things go poorly. We create the tagged buffers with something like: CMTagCollectionRef collections[2]; CMTag leftTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)0), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_LeftEye) }; CMTagCollectionCreate( kCFAllocatorDefault, leftTags, 2, &(collections[0]) ); CMTag rightTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)1), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_RightEye) }; CMTagCollectionCreate( kCFAllocatorDefault, rightTags, 2, &(collections[1]) ); CFArrayRef tagCollections = CFArrayCreate( kCFAllocatorDefault, (const void **)collections, 2, &kCFTypeArrayCallBacks ); CVPixelBufferRef buffers[] = {*b, *alt}; CFArrayRef b = CFArrayCreate( kCFAllocatorDefault, (const void **)buffers, 2, &kCFTypeArrayCallBacks ); CMTaggedBufferGroupRef bufferGroup; OSStatus res = CMTaggedBufferGroupCreate( kCFAllocatorDefault, tagCollections, b, &bufferGroup ); Perhaps there's something about this OBJC code that I've buggered up? Hopefully! Anyways, when I submit this tagged bugger group to the adaptor: if (![mvVideoAdapter appendTaggedPixelBufferGroup:bufferGroup withPresentationTime:pts]) { // report error... } Appending does not raise any errors - eventually it just hangs on us and we never return from it... Real Issue: So either: The delegate assigned to the AVAssetWriter doesn't fire its assetWriter callback which should produce the segments The adapter hangs on the appendTaggedPixelBufferGroup before a segment is ready to be completed (but succeeds for a number of buffer groups before this happens). This is the same delegate class that's assigned to the non multi view code path if MV-HEVC is turned off which works perfectly.
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121
Apr ’25
Screen recording audio and video out of sync
I use startCaptureWithHandler to record screen and AVAssetWriter appendSampleBuffer: to save audio and video ,but when played the saved file audio and video are out of sync. I don t know if it s a AVAssetWriterInputr setup problem,here is my code NSDictionary *audioCompressionSettings = @{ AVEncoderBitRatePerChannelKey : @(64000), AVFormatIDKey : @(kAudioFormatMPEG4AAC), AVNumberOfChannelsKey : @(2), AVSampleRateKey : @(44100) }; AVAssetWriterInput *audioAssetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioCompressionSettings]; audioAssetWriterInput.expectsMediaDataInRealTime = YES; [_assetWriter addInput:audioAssetWriterInput]; NSDictionary *videoCompressSetting = @{AVVideoAverageBitRateKey:@(screenWidth*screenHeight*5), AVVideoMaxKeyFrameIntervalKey:@(30), AVVideoProfileLevelKey : AVVideoProfileLevelH264MainAutoLevel}; NSDictionary *codecSetting = @{AVVideoCodecKey:AVVideoCodecTypeH264, AVVideoScalingModeKey : AVVideoScalingModeResize, AVVideoWidthKey:@(screenWidth*2), AVVideoHeightKey:@(screenHeight*2), AVVideoCompressionPropertiesKey:videoCompressSetting }; AVAssetWriterInput* videoAssetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:codecSetting]; videoAssetWriterInput.expectsMediaDataInRealTime = YES; [_assetWriter addInput:videoAssetWriterInput];
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144
Apr ’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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260
Apr ’25
Save MPEG-TS (h264 or HEVC) video stream using AVAssetWriter.
I'm capturing video stream from GoPro camera (I demux UDP MPEG-TS packets) and create CMSampleBuffers from them, this works fine when I display them using CMSampleBufferLayer. However when I dump them to disk using AVAssetWriter and then playback it with AVPlayer, AVPlayer has problems with scrubbing, it also cannot render previous frames, it needs to go back to key frames. Also thumbnails generated with AVAssetImageGenerator are mostly distorted and green, even though I set the requestedTimeToleranceAfter longer than the key frames frequency. When I re-encode saved video once again with AVAssetExportSession and play it back then I can scrub the video just fine. Is it because re-transcoding adds additional metadata to enable generating frames when rewinding the video and scrubbing? If so is there a way to achieve it with AVAssetWriter without much time penalty? I need the dump/save operation to be very fast. I also considered the following: Instead of de-muxing video and creating CMSampleBuffers, maybe I could directly dump the stream to disk and somehow add moov atoms with timing information. Would this approach work? If so where I can find information how to do it? Thank you!
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188
Apr ’25
Impact on iOS Due to Image Policy Changes with Android Target SDK 34
As the image access policy has changed with Android targeting SDK 34, I’m planning to update the way our app accesses photos. We are using the react-native-image-picker library to access images. On Android, the system no longer prompts the user for image access permissions, but on iOS, permission requests still appear. Since Android no longer requires explicit permissions, I’ve removed the permission request logic for Android. In this case, is it also safe to remove the permission request for iOS? In our app, photo access is only used for changing the user profile picture and attaching images when writing a post on the bulletin board. Are there any limitations or considerations for this kind of usage?
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111
Apr ’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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160
Apr ’25
Audio session activation occasionally fails from CarPlay
I'm working on adding CarPlay support to an audio app and am running into an issue. Occasionally, when a user opens the app from CarPlay while the main app scene is either not connected or is currently in the background, I will receive an error when attempting to activate the audio session. The code below mimics my setup: do { try AVAudioSession.sharedInstance().setCategory(.playback, mode: .spokenAudio) try AVAudioSession.sharedInstance().setActive(true) } catch { print(error) // NSOSStatusErrorDomain - 560557684: Session activation failed } That error code maps to AVAudioSession.ErrorCode.cannotInterruptOthers. Once in this state, all subsequent attempts to play different pieces of content will fail. However, things will start working normally if the user opens the app on their phone and tries again from CarPlay (while the app is in the foreground on their phone). I'm not sure why it would behave this way and want to note that I do have the audio background mode capability enabled. Has anyone else encountered this? Are there any workarounds or changes I could make to prevent this from happening?
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199
Apr ’25
CVPixelBufferCreate EXC_BAD_ACCESS
I am doing something similar to this post Within an AVCaptureDataOutputSynchronizerDelegate method, I create a pixelBuffer using CVPixelBufferCreate with the following attributes: kCVPixelBufferIOSurfacePropertiesKey as String: true, kCVPixelBufferIOSurfaceOpenGLESTextureCompatibilityKey as String: true When I copy the data from the vImagePixelBuffer "rotatedImageBuffer", I get the following error: Thread 10: EXC_BAD_ACCESS (code=1, address=0x14caa8000) I get the same error with memcpy and data.copyBytes (not running them at the same time obviously). If I use CVPixelBufferCreateWithBytes, I do not get this error. However, CVPixelBufferCreateWithBytes does not let you include attributes (see linked post above). I am using vImage because I need the original CVPixelBuffer from the camera output and a rotated version with a different color scheme. // Copy to pixel buffer let attributes: NSDictionary = [ true : kCVPixelBufferIOSurfacePropertiesKey, true : kCVPixelBufferIOSurfaceOpenGLESTextureCompatibilityKey, ] var colorBuffer: CVPixelBuffer? let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(rotatedImageBuffer.width), Int(rotatedImageBuffer.height), kCVPixelFormatType_32BGRA, attributes, &colorBuffer) //let status = CVPixelBufferCreateWithBytes(kCFAllocatorDefault, Int(rotatedImageBuffer.width), Int(rotatedImageBuffer.height), kCVPixelFormatType_32BGRA, rotatedImageBuffer.data, rotatedImageBuffer.rowBytes, nil, nil, attributes as CFDictionary, &colorBuffer) // does NOT produce error, but also does not have attributes guard status == kCVReturnSuccess, let colorBuffer = colorBuffer else { print("Failed to create buffer") return } let lockFlags = CVPixelBufferLockFlags(rawValue: 0) guard kCVReturnSuccess == CVPixelBufferLockBaseAddress(colorBuffer, lockFlags) else { print("Failed to lock base address") return } let colorBufferMemory = CVPixelBufferGetBaseAddress(colorBuffer)! let data = Data(bytes: rotatedImageBuffer.data, count: rotatedImageBuffer.rowBytes * Int(rotatedImageBuffer.height)) data.copyBytes(to: colorBufferMemory.assumingMemoryBound(to: UInt8.self), count: data.count) // Fails here //memcpy(colorBufferMemory, rotatedImageBuffer.data, rotatedImageBuffer.rowBytes * Int(rotatedImageBuffer.height)) // Also produces the same error CVPixelBufferUnlockBaseAddress(colorBuffer, lockFlags)
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Activity
Apr ’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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130
Activity
Apr ’25
Crackling/Popping sound when using AVAudioUnitTimePitch
I have a simple AVAudioEngine graph as follows: AVAudioPlayerNode -> AVAudioUnitEQ -> AVAudioUnitTimePitch -> AVAudioUnitReverb -> Main mixer node of AVAudioEngine. I noticed that whenever I have AVAudioUnitTimePitch or AVAudioUnitVarispeed in the graph, I noticed a very distinct crackling/popping sound in my Airpods Pro 2 when starting up the engine and playing the AVAudioPlayerNode and unable to find the reason why this is happening. When I remove the node, the crackling completely goes away. How do I fix this problem since i need the user to be able to control the pitch and rate of the audio during playback. import AVKit @Observable @MainActor class AudioEngineManager { nonisolated private let engine = AVAudioEngine() private let playerNode = AVAudioPlayerNode() private let reverb = AVAudioUnitReverb() private let pitch = AVAudioUnitTimePitch() private let eq = AVAudioUnitEQ(numberOfBands: 10) private var audioFile: AVAudioFile? private var fadePlayPauseTask: Task<Void, Error>? private var playPauseCurrentFadeTime: Double = 0 init() { setupAudioEngine() } private func setupAudioEngine() { guard let url = Bundle.main.url(forResource: "Song name goes here", withExtension: "mp3") else { print("Audio file not found") return } do { audioFile = try AVAudioFile(forReading: url) } catch { print("Failed to load audio file: \(error)") return } reverb.loadFactoryPreset(.mediumHall) reverb.wetDryMix = 50 pitch.pitch = 0 // Increase pitch by 500 cents (5 semitones) engine.attach(playerNode) engine.attach(pitch) engine.attach(reverb) engine.attach(eq) // Connect: player -> pitch -> reverb -> output engine.connect(playerNode, to: eq, format: audioFile?.processingFormat) engine.connect(eq, to: pitch, format: audioFile?.processingFormat) engine.connect(pitch, to: reverb, format: audioFile?.processingFormat) engine.connect(reverb, to: engine.mainMixerNode, format: audioFile?.processingFormat) } func prepare() { guard let audioFile else { return } playerNode.scheduleFile(audioFile, at: nil) } func play() { DispatchQueue.global().async { [weak self] in guard let self else { return } engine.prepare() try? engine.start() DispatchQueue.main.async { [weak self] in guard let self else { return } playerNode.play() fadePlayPauseTask?.cancel() playPauseCurrentFadeTime = 0 fadePlayPauseTask = Task { [weak self] in guard let self else { return } while true { let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: true) // Ramp up volume until 1 is reached if volume >= 1 { break } engine.mainMixerNode.outputVolume = volume try await Task.sleep(for: .milliseconds(10)) playPauseCurrentFadeTime += 0.01 } engine.mainMixerNode.outputVolume = 1 } } } } func pause() { fadePlayPauseTask?.cancel() playPauseCurrentFadeTime = 0 fadePlayPauseTask = Task { [weak self] in guard let self else { return } while true { let volume = updateVolume(for: playPauseCurrentFadeTime / 0.1, rising: false) // Ramp down volume until 0 is reached if volume <= 0 { break } engine.mainMixerNode.outputVolume = volume try await Task.sleep(for: .milliseconds(10)) playPauseCurrentFadeTime += 0.01 } engine.mainMixerNode.outputVolume = 0 playerNode.pause() // Shut down engine once ramp down completes DispatchQueue.global().async { [weak self] in guard let self else { return } engine.pause() } } } private func updateVolume(for x: Double, rising: Bool) -> Float { if rising { // Fade in return Float(pow(x, 2) * (3.0 - 2.0 * (x))) } else { // Fade out return Float(1 - (pow(x, 2) * (3.0 - 2.0 * (x)))) } } func setPitch(_ value: Float) { pitch.pitch = value } func setReverbMix(_ value: Float) { reverb.wetDryMix = value } } struct ContentView: View { @State private var audioManager = AudioEngineManager() @State private var pitch: Float = 0 @State private var reverb: Float = 0 var body: some View { VStack(spacing: 20) { Text("🎵 Audio Player with Reverb & Pitch") .font(.title2) HStack { Button("Prepare") { audioManager.prepare() } Button("Play") { audioManager.play() } .padding() .background(Color.green) .foregroundColor(.white) .cornerRadius(10) Button("Pause") { audioManager.pause() } .padding() .background(Color.red) .foregroundColor(.white) .cornerRadius(10) } VStack { Text("Pitch: \(Int(pitch)) cents") Slider(value: $pitch, in: -2400...2400, step: 100) { _ in audioManager.setPitch(pitch) } } VStack { Text("Reverb Mix: \(Int(reverb))%") Slider(value: $reverb, in: 0...100, step: 1) { _ in audioManager.setReverbMix(reverb) } } } .padding() } }
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285
Activity
Apr ’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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117
Activity
Apr ’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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119
Activity
Apr ’25
CoreAudio server plugin gaining write access with SystemConfiguration.framework functions
Hi, our CourAudio server plugin utilizes the SystemConfiguration.framework to store and restore specific shared system wide settings. While our application can authenticate to utilize the SystemConfiguration.framework to gain write access to the shared configuration settings the CoreAudio server plugin obviously can't have any user interaction and therefor does not authenticate. Is it possible to authenticate the CoreAudio server plugin to gain write permissions? Are there any entitlements or other means that would allow this? Thanks!
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187
Activity
Apr ’25
MusicKit - Skipping Forwards or Backwards does not update
Hello everyone, I am working on an app that allows you to review your own music using Apple Music. Currently I am running into an issue with the skipping forwards and backwards outside of the app. How it should work: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song on an album should play and the information should change to reflect that in the app. If you play a song in Apple Music, you can see a Now Playing view in the lock screen. When you skip forward or backwards, it will do either action and it would reflect that when you see a little frequency icon on artwork image of a song. What it's doing: When skipping forward or backwards on the lock or home screen of an iPhone, the next or previous song is reflected outside of the app, but not in the app. When skipping a song outside of the app, it works correctly to head to the next song. But when I return to the app, it is not reflected NOTE: I am not using MusicKit variables such as Track, Album to display the songs. Since I want to grab the songs and review them I need a rating so I created my own that grabs the MusicItemID, name, artist(s), etc. NOTE: I am using ApplicationMusicPlayer.shared Is there a way to get the song to reflect in my app? (If its easier, a simple example of it would be nice. No need to create an entire xprod file)
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101
Activity
Apr ’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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93
Activity
Apr ’25
Apple News Publisher: How To Successfully Apply
Hi there, Can anyone tell me how to possibly get approved as an Apple News Publisher in 2025? We attempted in 2024, but received this message from Apple support: "Thank you for your interest in Apple News. At this time, we're not accepting new applications." When I inquired further, I got this second response: "Apple News is no longer accepting unsolicited applications. To learn more about Apple News requirements, visit the Apple News support page. If you have any feedback, please use this form to send us your comments. Keep in mind that while we read all feedback, we are unable to respond to each submission individually." My questions are: Is this still the case? (Especially when you are a legit local news outlet) Is there a link to apply as a news publisher? I don't seem to have that option at all. Thanks for any feedback.
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137
Activity
Apr ’25
AVAssetWriterInputTaggedPixelBufferGroupAdaptor Hanging With Tagged Buffers
We've successfully implemented an AVAssetWriter to produce HLS streams (all code is Objective-C++ for interop with existing codebase) but are struggling to extend the operations to use tagged buffers. We're starting to wonder if the tagged buffers required for an MV-HEVC signal are fully supported when producing HLS segments in a live-stream setting. We generate a live stream of data using something like: UTType *t = [UTType typeWithIdentifier:AVFileTypeMPEG4]; m_writter = [[AVAssetWriter alloc] initWithContentType:t]; // - videoHint describes HEVC and width/height // - m_videoConfig includes compression settings and, when using MV-HEVC, // the correct keys are added (i.e. kVTCompressionPropertyKey_MVHEVCVideoLayerIDs) // The app was throwing an exception without these which was // useful to know when we got the configuration right. m_video = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:m_videoConfig sourceFormatHint:videoHint]; For either path we're producing CVPixelBufferRefs that contain the raw pixel information (i.e. 32BGRA) so we use an adapter to make that as simple as possible. If we use a single view and a AVAssetWriterInputPixelBufferAdaptor things work out very well. We produce segments and the delegate is called. However, if we use the AVAssetWriterInputTaggedPixelBufferGroupAdaptor as exampled in the SideBySideToMVHEVC demo project, things go poorly. We create the tagged buffers with something like: CMTagCollectionRef collections[2]; CMTag leftTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)0), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_LeftEye) }; CMTagCollectionCreate( kCFAllocatorDefault, leftTags, 2, &(collections[0]) ); CMTag rightTags[] = { CMTagMakeWithSInt64Value( kCMTagCategory_VideoLayerID, (int64_t)1), CMTagMakeWithSInt64Value( kCMTagCategory_StereoView, kCMStereoView_RightEye) }; CMTagCollectionCreate( kCFAllocatorDefault, rightTags, 2, &(collections[1]) ); CFArrayRef tagCollections = CFArrayCreate( kCFAllocatorDefault, (const void **)collections, 2, &kCFTypeArrayCallBacks ); CVPixelBufferRef buffers[] = {*b, *alt}; CFArrayRef b = CFArrayCreate( kCFAllocatorDefault, (const void **)buffers, 2, &kCFTypeArrayCallBacks ); CMTaggedBufferGroupRef bufferGroup; OSStatus res = CMTaggedBufferGroupCreate( kCFAllocatorDefault, tagCollections, b, &bufferGroup ); Perhaps there's something about this OBJC code that I've buggered up? Hopefully! Anyways, when I submit this tagged bugger group to the adaptor: if (![mvVideoAdapter appendTaggedPixelBufferGroup:bufferGroup withPresentationTime:pts]) { // report error... } Appending does not raise any errors - eventually it just hangs on us and we never return from it... Real Issue: So either: The delegate assigned to the AVAssetWriter doesn't fire its assetWriter callback which should produce the segments The adapter hangs on the appendTaggedPixelBufferGroup before a segment is ready to be completed (but succeeds for a number of buffer groups before this happens). This is the same delegate class that's assigned to the non multi view code path if MV-HEVC is turned off which works perfectly.
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121
Activity
Apr ’25
Screen recording audio and video out of sync
I use startCaptureWithHandler to record screen and AVAssetWriter appendSampleBuffer: to save audio and video ,but when played the saved file audio and video are out of sync. I don t know if it s a AVAssetWriterInputr setup problem,here is my code NSDictionary *audioCompressionSettings = @{ AVEncoderBitRatePerChannelKey : @(64000), AVFormatIDKey : @(kAudioFormatMPEG4AAC), AVNumberOfChannelsKey : @(2), AVSampleRateKey : @(44100) }; AVAssetWriterInput *audioAssetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioCompressionSettings]; audioAssetWriterInput.expectsMediaDataInRealTime = YES; [_assetWriter addInput:audioAssetWriterInput]; NSDictionary *videoCompressSetting = @{AVVideoAverageBitRateKey:@(screenWidth*screenHeight*5), AVVideoMaxKeyFrameIntervalKey:@(30), AVVideoProfileLevelKey : AVVideoProfileLevelH264MainAutoLevel}; NSDictionary *codecSetting = @{AVVideoCodecKey:AVVideoCodecTypeH264, AVVideoScalingModeKey : AVVideoScalingModeResize, AVVideoWidthKey:@(screenWidth*2), AVVideoHeightKey:@(screenHeight*2), AVVideoCompressionPropertiesKey:videoCompressSetting }; AVAssetWriterInput* videoAssetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:codecSetting]; videoAssetWriterInput.expectsMediaDataInRealTime = YES; [_assetWriter addInput:videoAssetWriterInput];
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144
Activity
Apr ’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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260
Activity
Apr ’25
Xcode 16.3 not showing any PhotoKit documentation for Objective-C but it does for Swift.
Has Objective-C been deprecated?
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173
Activity
Apr ’25
Save MPEG-TS (h264 or HEVC) video stream using AVAssetWriter.
I'm capturing video stream from GoPro camera (I demux UDP MPEG-TS packets) and create CMSampleBuffers from them, this works fine when I display them using CMSampleBufferLayer. However when I dump them to disk using AVAssetWriter and then playback it with AVPlayer, AVPlayer has problems with scrubbing, it also cannot render previous frames, it needs to go back to key frames. Also thumbnails generated with AVAssetImageGenerator are mostly distorted and green, even though I set the requestedTimeToleranceAfter longer than the key frames frequency. When I re-encode saved video once again with AVAssetExportSession and play it back then I can scrub the video just fine. Is it because re-transcoding adds additional metadata to enable generating frames when rewinding the video and scrubbing? If so is there a way to achieve it with AVAssetWriter without much time penalty? I need the dump/save operation to be very fast. I also considered the following: Instead of de-muxing video and creating CMSampleBuffers, maybe I could directly dump the stream to disk and somehow add moov atoms with timing information. Would this approach work? If so where I can find information how to do it? Thank you!
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188
Activity
Apr ’25
How to disable and enable build-in camera
Hi all, In MacOS, how can I disable or enable build-in camera by program or script?
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162
Activity
Apr ’25
Impact on iOS Due to Image Policy Changes with Android Target SDK 34
As the image access policy has changed with Android targeting SDK 34, I’m planning to update the way our app accesses photos. We are using the react-native-image-picker library to access images. On Android, the system no longer prompts the user for image access permissions, but on iOS, permission requests still appear. Since Android no longer requires explicit permissions, I’ve removed the permission request logic for Android. In this case, is it also safe to remove the permission request for iOS? In our app, photo access is only used for changing the user profile picture and attaching images when writing a post on the bulletin board. Are there any limitations or considerations for this kind of usage?
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111
Activity
Apr ’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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160
Activity
Apr ’25
Audio session activation occasionally fails from CarPlay
I'm working on adding CarPlay support to an audio app and am running into an issue. Occasionally, when a user opens the app from CarPlay while the main app scene is either not connected or is currently in the background, I will receive an error when attempting to activate the audio session. The code below mimics my setup: do { try AVAudioSession.sharedInstance().setCategory(.playback, mode: .spokenAudio) try AVAudioSession.sharedInstance().setActive(true) } catch { print(error) // NSOSStatusErrorDomain - 560557684: Session activation failed } That error code maps to AVAudioSession.ErrorCode.cannotInterruptOthers. Once in this state, all subsequent attempts to play different pieces of content will fail. However, things will start working normally if the user opens the app on their phone and tries again from CarPlay (while the app is in the foreground on their phone). I'm not sure why it would behave this way and want to note that I do have the audio background mode capability enabled. Has anyone else encountered this? Are there any workarounds or changes I could make to prevent this from happening?
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199
Activity
Apr ’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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90
Activity
Apr ’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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116
Activity
Apr ’25