Dive into the world of video on Apple platforms, exploring ways to integrate video functionalities within your iOS,iPadOS, macOS, tvOS, visionOS or watchOS app.

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The behavior of AVPlayerItem.didPlayToEndTimeNotification is not as expected in iOS 26.
Hello, Environment macOS 15.6.1 / Xcode 26 beta 7 / iOS 26 Beta 9 In a simple AVFoundation video-playback sample, I’m seeing different behavior between iOS 18 and iOS 26 regarding AVPlayerItem.didPlayToEndTimeNotification. I’ve attached a minimal sample below. Please replace videoURL with a valid short video URL. Repro steps Tap “Play” to start playback and let the video finish. The AVPlayerItem.didPlayToEndTimeNotification registered with NotificationCenter should fire, and you should see Play finished. in the console. Without relaunching, tap “Play” again. This is where the issue arises. Observed behavior On iOS 18 and earlier: The video does not play again (it does not restart from the beginning), but AVPlayerItem.didPlayToEndTimeNotification is posted and Play finished. appears in the console. The same happens every time you press “Play”. On iOS 26: Pressing “Play” does not post AVPlayerItem.didPlayToEndTimeNotification. The code path that prints Play finished. is never called (the callback enclosing that line is not invoked again). Building the same program with Xcode 16.4 and running it on an iOS 26 beta device shows the same phenomenon, which suggests there has been a behavioral change for AVPlayerItem.didPlayToEndTimeNotification on iOS 26. I couldn’t find any mention of this in the release notes or API Reference. Because the semantics around AVPlayerItem.didPlayToEndTimeNotification appear to differ, we’re forced to adjust our logic. If there is a way to achieve the iOS 18–style behavior on iOS 26, I would appreciate guidance. Alternatively, if this change is intentional, could you share the reasoning? Is iOS 26 the correct behavior from Apple’s perspective and iOS 18 (and earlier) behavior considered incorrect? Any official clarification would be extremely helpful. import UIKit import AVFoundation final class ViewController: UIViewController { private let videoURL = URL(string: "https://......mp4")! private var player: AVPlayer? private var playerItem: AVPlayerItem? private var playerLayer: AVPlayerLayer? private var observeForComplete: NSObjectProtocol? // UI private let playerContainerView = UIView() private let playButton = UIButton(type: .system) private let stopButton = UIButton(type: .system) private let replayButton = UIButton(type: .system) deinit { if let observeForComplete { NotificationCenter.default.removeObserver(observeForComplete) } } override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .systemBackground setupUI() setupPlayer() } override func viewDidLayoutSubviews() { super.viewDidLayoutSubviews() playerLayer?.frame = playerContainerView.bounds } // MARK: - Setup private func setupUI() { playerContainerView.translatesAutoresizingMaskIntoConstraints = false playerContainerView.backgroundColor = .black view.addSubview(playerContainerView) // Buttons playButton.setTitle("Play", for: .normal) stopButton.setTitle("Pause", for: .normal) replayButton.setTitle("RePlay", for: .normal) [playButton, stopButton, replayButton].forEach { $0.titleLabel?.font = .systemFont(ofSize: 16, weight: .semibold) $0.translatesAutoresizingMaskIntoConstraints = false $0.contentEdgeInsets = UIEdgeInsets(top: 10, left: 16, bottom: 10, right: 16) } let stack = UIStackView(arrangedSubviews: [playButton, stopButton, replayButton]) stack.axis = .horizontal stack.spacing = 16 stack.alignment = .center stack.distribution = .equalCentering stack.translatesAutoresizingMaskIntoConstraints = false view.addSubview(stack) NSLayoutConstraint.activate([ playerContainerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20), playerContainerView.leadingAnchor.constraint(equalTo: view.leadingAnchor), playerContainerView.trailingAnchor.constraint(equalTo: view.trailingAnchor), playerContainerView.heightAnchor.constraint(equalToConstant: 200), stack.topAnchor.constraint(equalTo: playerContainerView.bottomAnchor, constant: 20), stack.centerXAnchor.constraint(equalTo: view.centerXAnchor) ]) // Action playButton.addTarget(self, action: #selector(didTapPlay), for: .touchUpInside) stopButton.addTarget(self, action: #selector(didTapStop), for: .touchUpInside) replayButton.addTarget(self, action: #selector(didTapReplayFromStart), for: .touchUpInside) } private func setupPlayer() { // AVURLAsset -> AVPlayerItem → AVPlayer let asset = AVURLAsset(url: videoURL) let item = AVPlayerItem(asset: asset) self.playerItem = item let player = AVPlayer(playerItem: item) player.automaticallyWaitsToMinimizeStalling = true self.player = player let layer = AVPlayerLayer(player: player) layer.videoGravity = .resizeAspect playerContainerView.layer.addSublayer(layer) layer.frame = playerContainerView.bounds self.playerLayer = layer // Notification if let observeForComplete { NotificationCenter.default.removeObserver(observeForComplete) } if let playerItem { observeForComplete = NotificationCenter.default.addObserver( forName: AVPlayerItem.didPlayToEndTimeNotification, object: playerItem, queue: .main ) { [weak self] _ in guard self != nil else { return } Task { @MainActor in print("Play finished.") } } } } // MARK: - Actions @objc private func didTapPlay() { player?.play() } @objc private func didTapStop() { player?.pause() } // RePlay @objc private func didTapReplayFromStart() { player?.seek(to: .zero, toleranceBefore: .zero, toleranceAfter: .zero) { [weak self] _ in self?.player?.play() } } } I would greatly appreciate an official response from Apple engineering on whether this is an intentional change, a regression, or an API contract clarification, and what the recommended approach is going forward. Thank you.
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751
Sep ’25
Enterprise API Passthrough in screen capture not working after visionOS26 update
We have been using passthrough in screen capture since visionOS26 with broadcast upload extension which was working in visionOS2.2 but now with visionOS26 it doesn't update. It fails with Invalid Broadcast session started, after a few seconds of starting the broadcast session. Is there a bug filed for it? or is it a known bug for it?
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409
Oct ’25
iPhone 17 Pro, 17 Pro Maxで撮った映像をWebRTCで送るとブラウザで表示した際に緑の映像になる
iPhoneで撮影した映像をブラウザのアプリへ送信して画面に映す機能を持ったアプリを開発しています。 iPhone 17 Pro, 17 Pro Maxでこのアプリを利用するとブラウザ側に表示される映像が緑一色や、緑がメインのカラフルな映像になってしまいます。 調べてみると17Proと17ProMaxで超広角カメラと望遠カメラの画素数が変更になっている(1200万画素→4800万画素)ためエンコーディングで失敗しているのではないかと疑っています。 なんでも情報下さい。 環境情報 WebRTCライブラリ: GoogleWebRTC バージョン 1.1 (CocoaPodsで導入) シグナリングサーバー: AWS Kinesis Video Streams 問題が発生するデバイス: モデル名: iPhone18,1, OS: 26.0 モデル名: iPhone18,1, OS: 26.1 問題が発生しないデバイス: iPhone17,5 以前の多数のモデル モデル名: iPhone18,1, OS: 26.0 モデル名: iPhone18,3, OS: 26.0
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241
Nov ’25
WKWebView Crashes on iOS During YouTube Playlist Playback
I’m encountering a consistent crash in WebKit when using WKWebView to play a YouTube playlist in my iOS app. Playback starts successfully, but the web process terminates during the second video in the playlist. This only occurs on physical devices, not in the simulator. Here’s a simplified Swift example of my setup: import SwiftUI import WebKit struct ContentView: View { private let playlistID = "PLig2mjpwQBZnghraUKGhCqc9eAy0UbpDN" var body: some View { YouTubeWebView(playlistID: playlistID) .edgesIgnoringSafeArea(.all) } } struct YouTubeWebView: UIViewRepresentable { let playlistID: String func makeUIView(context: Context) -> WKWebView { let config = WKWebViewConfiguration() config.allowsInlineMediaPlayback = true let webView = WKWebView(frame: .zero, configuration: config) webView.scrollView.isScrollEnabled = true let html = """ <!doctype html> <html> <head> <meta name="viewport" content="initial-scale=1.0, maximum-scale=1.0"> <style>body,html{height:100%;margin:0;background:#000}iframe{width:100%;height:100%;border:0}</style> </head> <body> <iframe src="https://www.youtube-nocookie.com/embed/videoseries?list=\(playlistID)&controls=1&rel=0&playsinline=1&iv_load_policy=3" frameborder="0" allow="encrypted-media; picture-in-picture; fullscreen" webkit-playsinline allowfullscreen ></iframe> </body> </html> """ webView.loadHTMLString(html, baseURL: nil) return webView } func updateUIView(_ uiView: WKWebView, context: Context) {} } #Preview { ContentView() } Observed behavior: First video plays without issue. Web process crashes when the second video in the playlist starts. Console logs show WebProcessProxy::didClose and repeated memory status messages. Using ProcessAssertion or background activity does not prevent the crash. Only occurs on physical devices; simulators do not reproduce the issue. Questions: Is there something I should change or add in my WKWebView setup or HTML/iframe to prevent the crash when playing the second video in a playlist on physical iOS devices? Is there an officially supported way to limit memory or prevent WebKit from terminating the web process during multi-video playback? Are there recommended patterns for playing YouTube playlists in a WKWebView on iOS without risking crashes? Any tips for debugging or configuring WKWebView to make it more stable for continuous playlist playback? Thanks in advance for any guidance!
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475
Oct ’25
Accessing External Timecode from Blackmagic ProDock in Custom App
Hi everyone, I’m exploring using the iPhone 17 Pro with the Blackmagic ProDock in a custom capture app. The genlock functionality seems accessible via AVExternalSyncDevice and related APIs, which is great. I’m specifically curious about external timecode coming in from the ProDock: • Is there a public way to access the timecode feed in a custom app via AVFoundation or another Apple API? • If so, what is the recommended approach to read or apply that timecode during capture? • Are there any current limitations or entitlements required to access timecode from ProDock in a third-party app? I’m excited to start integrating synchronized capture in my app, and any guidance or sample patterns would be greatly appreciated. Thanks in advance! — [Artem]
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292
Oct ’25
VTLowLatencyFrameInterpolationConfiguration supported dimensions
Is there limits on the supported dimension for VTLowLatencyFrameInterpolationConfiguration. Querying VTLowLatencyFrameInterpolationConfiguration.maximumDimensions and VTLowLatencyFrameInterpolationConfiguration.minimumDimensions returns nil. When I try the WWDC sample project EnhancingYourAppWithMachineLearningBasedVideoEffects with a 4k video this statement try frameProcessor.startSession(configuration: configuration) executes but try await frameProcessor.process(parameters: parameters) throws error Error Domain=VTFrameProcessorErrorDomain Code=-19730 "Processor is not initialized" UserInfo={NSLocalizedDescription=Processor is not initialized}. Also, why is VTLowLatencyFrameInterpolationConfiguration able to run while app is backgrounded but VTFrameRateConversionParameters can't (due to gpu usage)?
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354
Dec ’25
Control system video effects support for CMIO extension
We're distributing a virtual camera with our app that does not profit in the slightest from automatically applied system video effects both to the video going in (physical camera device) or out (virtual camera device). I'm aware of setting NSCameraReactionEffectGesturesEnabledDefault in Info.plist and determining active video effects via AVCaptureDevice API. Those are obviously crutches, because having to tell users to go look for and click around in menu bar apps is the opposite of a great UX. To make our product's video output more deterministic, I'm looking for a way to tell the CMIO subsystem that our virtual camera does not support any of the system video effects. I'm seeing properties like AVCaptureDevice.Format.isPortraitEffectSupported and AVCaptureDevice.Format.isStudioLightSupported whose documentation refers to the format's ability to support these effects. Since we're setting a CMFormatDescription via CMIOExtensionStreamSource.formats I was hoping to find something in the extensions, but wasn't successful so far. Can this be done?
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225
Nov ’25
Attaching color properties to CVPixelBufferRef
I believe this should work: CFMutableDictionaryRef attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionaryAddValue(attrs, kCVImageBufferColorPrimariesKey, kCVImageBufferColorPrimaries_ITU_R_709_2); CFDictionaryAddValue(attrs, kCVImageBufferTransferFunctionKey, kCVImageBufferTransferFunction_ITU_R_709_2); CFDictionaryAddValue(attrs, kCVImageBufferYCbCrMatrixKey, kCVImageBufferYCbCrMatrix_ITU_R_709_2); CVPixelBufferRef pixelBuffer = NULL; CVPixelBufferCreate(kCFAllocatorDefault, width, height, kCVPixelFormatType_32ARGB, attrs, &pixelBuffer); assert(CFDictionaryGetCount(CVBufferGetAttachments(pixelBuffer, kCVAttachmentMode_ShouldPropagate)) > 0); But that last assert fails, so it appears the color info does not get attached. kCVImageBufferColorPrimariesKey and the others are not one of the keys listed under BufferAttributeKeys, but I think they're supposed to be allowed because they're listed by CMVideoFormatDescriptionGetExtensionKeysCommonWithImageBuffers(). I'm hoping that putting the color matrix info in there will control how AVAssetWriter converts the RGB to YCbCr.
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338
Nov ’25
is the output frame rate of a CMIOExtension rounded or capped?
I made a CMIOExtension (a virtual camera) which generates its own output, for use in our in-house software testing. I wanted to make a video source with 29.97, 30, 59.94 and 60fps output. To this end, I created a CMIOExtensionDeviceSource which creates a CMIOExtensionDevice with one CMIOExtensionStreamSource with various stream formats contained in [CMIOExtensionStreamFormat], including one with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1000, timescale: 30000) and another with both maxFrameDuration and minFrameDuration = CMTimeMake(value: 1001, timescale: 30000) I've held off on the creation of the 59.94/60fps source for now until this problem is resolved. my virtual camera works, it produces a signal, but when I examine its associated AVCaptureDevice in the debugger, I find (lldb) po self.captureDevice?.formats[0].videoSupportedFrameRateRanges[0].maxFrameDuration ▿ Optional<CMTime> ▿ some : CMTime - value : 1000000 - timescale : 30000000 ▿ flags : CMTimeFlags - rawValue : 1 - epoch : 0 I get the same value, 1000000/30000000, or exactly 30fps, for all the formats of my AVCaptureDevice. Is there something I'm doing wrong, or do CMIOExtensionDevices always round the frame rates? I can't force CoreMediaIO to produce frames at exactly my desired frame interval, but I'd like to ensure that the average frame rate is my desired rate. How can I do that? Frame emission is governed by a repeating DispatchSourceTimer with a repeat time specified in nanoseconds with the TimerFlags set to 'strict'.
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548
1w
AVPlayerView. Internal constraints conflicts
I’m getting Auto Layout constraint conflict warnings related to AVPlayerView in my project. I’ve reproduced the issue on macOS Tahoe 26.2. The conflict appears to originate inside AVPlayerView itself, between its internal subviews, rather than in my own layout code. This issue can be easily reproduced in an empty project by simply adding an AVPlayerView as a subview using the code below. class ViewController: NSViewController { override func viewDidLoad() { super.viewDidLoad() let playerView = AVPlayerView() view.addSubview(playerView) } } After presenting that view controller, the following Auto Layout constraint conflict warnings appear in the console: Conflicting constraints detected: <decode: bad range for [%@] got [offs:346 len:1057 within:0]>. Will attempt to recover by breaking <decode: bad range for [%@] got [offs:1403 len:81 within:0]>. Unable to simultaneously satisfy constraints: ( "<NSLayoutConstraint:0xb33c29950 H:|-(0)-[AVDesktopPlayerViewContentView:0x10164dce0](LTR) (active, names: '|':AVPlayerView:0xb32ecc000 )>", "<NSLayoutConstraint:0xb33c299a0 AVDesktopPlayerViewContentView:0x10164dce0.right == AVPlayerView:0xb32ecc000.right (active)>", "<NSAutoresizingMaskLayoutConstraint:0xb33c62850 h=--& v=--& AVPlayerView:0xb32ecc000.width == 0 (active)>", "<NSLayoutConstraint:0xb33d46df0 H:|-(0)-[AVEventPassthroughView:0xb33cfb480] (active, names: '|':AVDesktopPlayerViewContentView:0x10164dce0 )>", "<NSLayoutConstraint:0xb33d46e40 AVEventPassthroughView:0xb33cfb480.trailing == AVDesktopPlayerViewContentView:0x10164dce0.trailing (active)>", "<NSLayoutConstraint:0xb33ef8320 NSGlassView:0xb33ed8c00.trailing == AVEventPassthroughView:0xb33cfb480.trailing - 6 (active)>", "<NSLayoutConstraint:0xb33ef8460 NSGlassView:0xb33ed8c00.width == 180 (active)>", "<NSLayoutConstraint:0xb33ef84b0 NSGlassView:0xb33ed8c00.leading >= AVEventPassthroughView:0xb33cfb480.leading + 6 (active)>" ) Will attempt to recover by breaking constraint <NSLayoutConstraint:0xb33ef8460 NSGlassView:0xb33ed8c00.width == 180 (active)> Set the NSUserDefault NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES to have -[NSWindow visualizeConstraints:] automatically called when this happens. And/or, set a symbolic breakpoint on LAYOUT_CONSTRAINTS_NOT_SATISFIABLE to catch this in the debugger. Is it system bug or maybe someone knows how to fix that? Thank you.
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699
1w
AVCaptureDevice.RotationCoordinator.videoRotationAngleForHorizonLevelCapture: behavior is different with iPhone 17
The front facing camera on iPhone 16 (and every model previous) gives the following values for AVCaptureDevice.RotationCoordinator.videoRotationAngleForHorizonLevelCapture: 90 degrees portrait 180 degrees landscape left 270 degrees for upside-down 0 degrees for landscape right Using these values a transform is calculated: var transform: CGAffineTransform { let degrees = rotationCoordinator.videoRotationAngleForHorizonLevelCapture let radians = degrees * .pi / 180.0 return CGAffineTransform(rotationAngle: radians) } And then applied to the AVAssetInput: videoInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings, sourceFormatHint: videoFormatDescription) videoInput.transform = transform And this ensures the correct transform is added to the metadata so that the recorded video plays in the correct orientation. However, with the iPhone 17 Pro and iPhone 17 Pro Max front facing cameras, AVCaptureDevice.RotationCoordinator.videoRotationAngleForHorizonLevelCapture return the different values: 0 degrees portrait 90 degrees landscape left 180 degrees for upside-down 270 degrees for landscape right So this approach breaks down, and the video orientation is incorrect. How is this intended to be handled?
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467
1w
AVPlayer unpredictable range requests on iOS when streaming *.mov file
Hi all, I'm trying to diagnose and resolve an issue with stuttering video playback using the standard AVPlayer. The video in question is a 4K, 39-second file in *.mov format, being played on an iOS device. It's served via a local HTTP server that proxies requests to a backend to fetch and process the content. The project uses end-to-end encrypted storage, which necessitates the proxy for handling data processing. While playback in offline scenarios is smooth, we are encountering issues with smooth playback during streaming. The same video streams smoothly on other platforms using the same connection, so network limitations are not a factor. On iOS, playback is consistently choppy, with pauses every 1-3 seconds. The video does not appear to buffer adequately for smooth playback. One particularly curious aspect is the seemingly random pattern of Content-Range requests made by the AVPlayer when streaming the video. Below is an example of the range requests:
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535
Apr ’25
Missing Depth Frames When Recording with AVCaptureVideoDataOutputSampleBufferDelegate/AVCaptureDataOutputSynchronizerDelegate and AVAssetWriter
I’ve tried both AVCaptureVideoDataOutputSampleBufferDelegate (captureOutput) and AVCaptureDataOutputSynchronizerDelegate (dataOutputSynchronizer), but the number of depth frames and saved timestamps is significantly lower than the number of frames in the .mp4 file written by AVAssetWriter. In my code, I save: Timestamps for each frame to a metadata file Depth frames to a binary file Video to an .mp4 file If I record a 4-second video at 30fps, the .mp4 file correctly plays for 4 seconds, but the number of stored timestamps and depth frames is much lower—around 70 frames instead of the expected 120. Does anyone know why this mismatch happens? func dataOutputSynchronizer(_ synchronizer: AVCaptureDataOutputSynchronizer, didOutput synchronizedDataCollection: AVCaptureSynchronizedDataCollection) { // Read all outputs guard let syncedDepthData: AVCaptureSynchronizedDepthData = synchronizedDataCollection.synchronizedData(for: depthDataOutput) as? AVCaptureSynchronizedDepthData, let syncedVideoData: AVCaptureSynchronizedSampleBufferData = synchronizedDataCollection.synchronizedData(for: videoDataOutput) as? AVCaptureSynchronizedSampleBufferData else { // only work on synced pairs return } if syncedDepthData.depthDataWasDropped || syncedVideoData.sampleBufferWasDropped { return } let depthData = syncedDepthData.depthData let depthPixelBuffer = depthData.depthDataMap let sampleBuffer = syncedVideoData.sampleBuffer guard let videoPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer), let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer) else { return } addToPreviewStream?(CIImage(cvPixelBuffer: videoPixelBuffer)) if !canWrite() { return } // Extract the presentation timestamp (PTS) from the sample buffer let timestamp = CMSampleBufferGetPresentationTimeStamp(sampleBuffer) //sessionAtSourceTime is the first buffer we will write to the file if self.sessionAtSourceTime == nil { //Make sure we don't start recording until the buffer reaches the correct time (buffer is always behind, this will fix the difference in time) guard sampleBuffer.presentationTimeStamp >= self.recordFromTime! else { return } self.sessionAtSourceTime = sampleBuffer.presentationTimeStamp self.videoWriter!.startSession(atSourceTime: sampleBuffer.presentationTimeStamp) } if self.videoWriterInput!.isReadyForMoreMediaData { self.videoWriterInput!.append(sampleBuffer) self.videoTimestamps.append( Timestamp( frame: videoTimestamps.count, value: timestamp.value, timescale: timestamp.timescale ) ) let ddm = depthData.depthDataMap depthCapture.addDepthData(pixelBuffer: ddm, timestamp: timestamp) } }
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475
Feb ’25
Configuring CaptureVideoDelegate to avoid gamma/transfer function
I'm working on an application that uses the iPhone camera for scientific purposes - and, as a result would like to receive video in as unprocessed format as possible. In particular, I'm interested in getting pixel buffers that contain pretty much the bayer data as the sensor sees it - with the minimum processing of color possible. Currently we configure the AVCaptureDevice to fix the focus and exposure, use a low ISO with no gain and set the white balance gains to 1. AVCaptureVideoDataOutput is using 32BGRA. What I'd like to do is remove any additional color and brightness processing such that the data is effectively processed with a linear transfer function (i.e. gamma function is 1). I thought that this might be down to using the AVCaptureDevice activeColorSpace - we currently use P3_D65 for this. But there only seems to be a few choices (e.g. sRGB, HLG_BT2020) all of which I think affect the gamma. So: is it possible to control or specify the gamma / transfer function when using CaptureVideoDelegate? if not, does one of the color space settings have a defined gamma function that I can effectively reverse it from the pixel data without losing too much information? or is there a better way to capture video-ish speed images (15-30fps) from the camera sensor that skips processing like this? Many thanks for any suggestions.
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133
Mar ’25
Coverting CVPixelBuffer 2VUY to a Metal Texture
I am working on a project for macOS where I am taking an AVCaptureSession's CVPixelBuffer and I need to convert it into a MTLTexture for rendering. On macOS the pixel format is 2vuy, there does not seem to be a clear format conversion while converting to a metal texture. I have been able to convert it to a texture but the color space seems to be off as it is rendering distorted colors with a double image. I believe 2vuy is a single pane color space and I have tried to account for that, but I am unaware of what is off. I have attached The CVPixelBuffer and The distorted MTLTexture along with a laundry list of errors. On iOS my conversions are fine, it is only the macOS 2vuy pixel format that seems to have issues. My code for the conversion is also attached. If there are any suggestions or guidance on how to properly convert a 2vuy CVPixelBuffer to a MTLTexture I would greatly appreciate it. Many Thanks Conversion_Logs.txt ConversionCode.swift
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208
Apr ’25
AVCaptureSession video and audio out of sync
I'm using an AVCaptureSession to send video and audio samples to an AVAssetWriter. When I play back the resultant video, sometimes there is a significant lag between the audio compared with the video, so they're just not in sync. But sometimes they are, with the same code. If I look at the very first presentation time stamps of the buffers being sent to the delegate, via func captureOutput(_: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) I see something like this: Adding audio samples for pts time 227711.0855328798, Adding video samples for pts time 227710.778785374 That is, the clock for audio vs video is behind: the first audio sample I receive is at 11.08 something, while the video video sample is earlier in time, at 10.778 something. The times are the presentation time stamps of the buffer, and the outputPresentationTimeStamp is the exact same number. It feels like "video" vs the "audio" clock are just mismatched. This doesn't always happen: sometimes they're synced. Sometimes they're not. Any ideas? The device I'm recording is a webcam, on iPadOS, connected via the usb-c port.
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169
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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163
Apr ’25
PHPickerViewController Not Offering public.hevc UTI for a Known HEVC Video
I'm working on an app where a user needs to select a video from their Photos library, and I need to get the original, unmodified HEVC (H.265) data stream to preserve its encoding. The Problem I have confirmed that my source videos are HEVC. I can record a new video with my iPhone 15 Pro Max camera set to "High Efficiency," export the "Unmodified Original" from Photos on my Mac, and verify that the codec is MPEG-H Part2/HEVC (H.265). However, when I select that exact same video in my app using PHPickerViewController, the itemProvider does not list public.hevc as an available type identifier. This forces me to fall back to a generic movie type, which results in the system providing me with a transcoded H.264 version of the video. Here is the debug output from my app after selecting a known HEVC video: ⚠️ 'public.hevc' not found. Falling back to generic movie type (likely H.264). What I've Tried My code explicitly checks for the public.hevc identifier in the registeredTypeIdentifiers array. Since it's not found, my HEVC-specific logic is never triggered. Here is a minimal version of my PHPickerViewControllerDelegate implementation: import UniformTypeIdentifiers // ... inside the Coordinator class ... func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) { picker.dismiss(animated: true) guard let result = results.first else { return } let itemProvider = result.itemProvider let hevcIdentifier = "public.hevc" let identifiers = itemProvider.registeredTypeIdentifiers print("Available formats from itemProvider: \(identifiers)") if identifiers.contains(hevcIdentifier) { print("✅ HEVC format found, requesting raw data...") itemProvider.loadDataRepresentation(forTypeIdentifier: hevcIdentifier) { (data, error) in // ... process H.265 data ... } } else { print("⚠️ 'public.hevc' not found. Falling back to generic movie type (likely H.264).") itemProvider.loadFileRepresentation(forTypeIdentifier: UTType.movie.identifier) { url, error in // ... process H.264 fallback ... } } } My Environment Device: iPhone 15 Pro Max iOS Version: iOS 18.5 Xcode Version: 16.2 My Questions Are there specific conditions (e.g., the video being HDR/Dolby Vision, Cinematic, or stored in iCloud) under which PHPickerViewController's itemProvider would intentionally not offer the public.hevc type identifier, even for an HEVC video? What is the definitive, recommended API sequence to guarantee that I receive the original, unmodified data stream for a video asset, ensuring that no transcoding to H.264 occurs during the process? Any insight into why public.hevc might be missing from the registeredTypeIdentifiers for a known HEVC asset would be greatly appreciated. Thank you.
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174
Jul ’25
What changes were made to the VideoToolbox HEVC encoder in iOS 26?
Because I want to control the grid size and number of HEIC images myself, I decided to perform HEVC encoding manually and then generate the HEIC image. Previously, I used VTCompressionSession to accomplish this task, and the results were satisfactory. It worked perfectly on iOS 16 through iOS 18 — in other words, it was able to generate correct HEVC encoding, and its CMFormatDescription should also have been correct, since I relied on it to generate the decoderConfig; otherwise, the final image would have decoding issues. However, it can no longer generate a valid HEIC image on a physical device running iOS 26. Interestingly, it still works fine on the iOS 26 simulator — it only fails on real hardware. The abnormal result is that the image becomes completely black, although the image dimensions are still correct. After my troubleshooting, I suspect that the encoding behavior of VTCompressionSession has been modified on iOS 26, which causes the final hvc1 encoding I pass in to be incorrect. I created a VTCompressionSession using the following configuration. var newSession: VTCompressionSession! var status = VTCompressionSessionCreate( allocator: kCFAllocatorDefault, width: Int32(frameSize.width), height: Int32(frameSize.height), codecType: kCMVideoCodecType_HEVC, encoderSpecification: nil, imageBufferAttributes: nil, compressedDataAllocator: nil, outputCallback: nil, refcon: nil, compressionSessionOut: &newSession ) try check(status, VideoToolboxErrorDomain) let properties: [CFString: Any] = [ kVTCompressionPropertyKey_AllowFrameReordering: false, kVTCompressionPropertyKey_AllowTemporalCompression: false, kVTCompressionPropertyKey_RealTime: false, kVTCompressionPropertyKey_MaximizePowerEfficiency: false, kVTCompressionPropertyKey_ProfileLevel: profileLevel, kVTCompressionPropertyKey_Quality: quality.rawValue, ] status = VTSessionSetProperties(newSession, propertyDictionary: properties as CFDictionary) try check(status, VideoToolboxErrorDomain) { VTCompressionSessionInvalidate(newSession) } Then use the following code to encode each Grid of the image. let status = VTCompressionSessionEncodeFrame( session, imageBuffer: buffer, presentationTimeStamp: presentationTimeStamp, duration: frameDuration, frameProperties: nil, infoFlagsOut: nil) { [weak self] status, _, sampleBuffer in try check(status, VideoToolboxErrorDomain) if let sampleBuffer { let encodedImage = try self.encodedImage(from: sampleBuffer) // handle encodedImage } } try check(status, VideoToolboxErrorDomain) If I try to display this abnormal image in the App, my console outputs the following error, so it can be inferred that the issue probably occurred during decoding. createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray createImageBlock:3029: *** ERROR: CGImageBlockCreate {0, 0, 2316, 6176} - data is NULL callDecodeImage:2411: *** ERROR: decodeImageImp failed - NULL _blockArray It needs to be emphasized again that this code used to work fine in the past, and the issue only occurs on an iOS 26 physical device. I noticed that iOS 26 has introduced many new properties, but I’m not sure whether some of these new properties must be set in the new system, and there’s no information about this in the official documentation.
3
0
525
Sep ’25
VTFrameRateConversionConfiguration don't support 640x480
hello, I'm using VideoTololbox VTFrameRateConversionConfiguration to perform frame interpolation: https://developer.apple.com/documentation/videotoolbox/vtframerateconversionconfiguration?language=objc ,when using 640x480 vidoe input, I got error: Error ! Invalid configuration [VEEspressoModel] build failure : flow_adaptation_feature_extractor_rev2.espresso.net. Configuration: landscape640x480 [EpsressoModel] Cannot load Net file flow_adaptation_feature_extractor_rev2.espresso.net. Configuration: landscape640x480 Error: failed to create FRCFlowAdaptationFeatureExtractor for usage 8 Failed to switch (0x12c40e140) [usage:8, 1/4 flow:0, adaptation layer:1, twoStage:0, revision:2, flow size (320x240)]. Could not init FlowAdaptation initFlowAdaptationWithError fail tried 2048x1080 is ok.
3
0
344
Dec ’25