I'm building a Swift video editor with AVFoundation and a custom compositor. Despite setting AVVideoComposition.frameDuration to 60 FPS, I'm seeing significant frame skipping during playback. Console Output Shows Frame Skipping Frame #0 at 0.0 ms (fps: 60.0) Frame #2 at 33.333333333333336 ms (fps: 60.0) Frame #6 at 100.0 ms (fps: 60.0) Frame #10 at 166.66666666666666 ms (fps: 60.0) Frame #32 at 533.3333333333334 ms (fps: 60.0) Frame #62 at 1033.3333333333335 ms (fps: 60.0) Frame #96 at 1600.0 ms (fps: 60.0) Instead of frames every ~16.67ms (60 FPS), I'm getting irregular intervals, sometimes 33ms, 67ms, or hundreds of milliseconds apart. Renderer.swift (Key Parts) @MainActor class Renderer: ObservableObject { @Published var playerItem: AVPlayerItem? private let assetManager: ProjectAssetManager? private let compositorId: String func buildComposition() async { // ... load mouse moves/clicks data ... let composition = AVMutableComposition() let videoTrack = composition.addMutableTrack( withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid ) var currentTime = CMTime.zero var layerInstructions: [AVMutableVideoCompositionLayerInstruction] = [] // Insert video segments for videoURL in videoURLs { let asset = AVAsset(url: videoURL) let tracks = try await asset.loadTracks(withMediaType: .video) let assetVideoTrack = tracks.first let duration = try await asset.load(.duration) try videoTrack.insertTimeRange( CMTimeRange(start: .zero, duration: duration), of: assetVideoTrack, at: currentTime ) let layerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack) let transform = try await assetVideoTrack.load(.preferredTransform) layerInstruction.setTransform(transform, at: currentTime) layerInstructions.append(layerInstruction) currentTime = CMTimeAdd(currentTime, duration) } let videoComposition = AVMutableVideoComposition() videoComposition.frameDuration = CMTime(value: 1, timescale: 60) // 60 FPS // Set render size from first video if let firstURL = videoURLs.first { let firstAsset = AVAsset(url: firstURL) let firstTrack = try await firstAsset.loadTracks(withMediaType: .video).first let naturalSize = try await firstTrack.load(.naturalSize) let transform = try await firstTrack.load(.preferredTransform) videoComposition.renderSize = CGSize( width: abs(naturalSize.applying(transform).width), height: abs(naturalSize.applying(transform).height) ) } let instruction = CompositorInstruction() instruction.timeRange = CMTimeRange(start: .zero, duration: currentTime) instruction.layerInstructions = layerInstructions instruction.compositorId = compositorId videoComposition.instructions = [instruction] videoComposition.customVideoCompositorClass = CustomVideoCompositor.self let playerItem = AVPlayerItem(asset: composition) playerItem.videoComposition = videoComposition self.playerItem = playerItem } } class CompositorInstruction: NSObject, AVVideoCompositionInstructionProtocol { var timeRange: CMTimeRange = .zero var enablePostProcessing: Bool = false var containsTweening: Bool = false var requiredSourceTrackIDs: [NSValue]? var passthroughTrackID: CMPersistentTrackID = kCMPersistentTrackID_Invalid var layerInstructions: [AVVideoCompositionLayerInstruction] = [] var compositorId: String = "" } class CustomVideoCompositor: NSObject, AVVideoCompositing { var sourcePixelBufferAttributes: [String : Any]? = [ kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32BGRA) ] var requiredPixelBufferAttributesForRenderContext: [String : Any] = [ kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32BGRA) ] func renderContextChanged(_ newRenderContext: AVVideoCompositionRenderContext) {} func startRequest(_ asyncVideoCompositionRequest: AVAsynchronousVideoCompositionRequest) { guard let sourceTrackID = asyncVideoCompositionRequest.sourceTrackIDs.first?.int32Value, let sourcePixelBuffer = asyncVideoCompositionRequest.sourceFrame(byTrackID: sourceTrackID), let outputBuffer = asyncVideoCompositionRequest.renderContext.newPixelBuffer() else { asyncVideoCompositionRequest.finish(with: NSError(domain: "VideoCompositor", code: -1)) return } let videoComposition = asyncVideoCompositionRequest.renderContext.videoComposition let frameDuration = videoComposition.frameDuration let fps = Double(frameDuration.timescale) / Double(frameDuration.value) let compositionTime = asyncVideoCompositionRequest.compositionTime let seconds = CMTimeGetSeconds(compositionTime) let frameInMilliseconds = seconds * 1000 let frameNumber = Int(round(seconds * fps)) print("Frame #\(frameNumber) at \(frameInMilliseconds) ms (fps: \(fps))") asyncVideoCompositionRequest.finish(withComposedVideoFrame: outputBuffer) } func cancelAllPendingVideoCompositionRequests() {} } VideoPlayerViewModel @MainActor class VideoPlayerViewModel: ObservableObject { let player = AVPlayer() private let renderer: Renderer func loadVideo() async { await renderer.buildComposition() if let playerItem = renderer.playerItem { player.replaceCurrentItem(with: playerItem) } } } What I've Tried Frame skipping is consistent—exact same timestamps on every playback Issue persists even with minimal processing (just passing through buffers) Occurs regardless of compositor complexity Please note that I need every frame at exact millisecond intervals for my application. Frame loss or inconsistent frameInMillisecond values are not acceptable.

方法不执行，当我点击avplayerviewcontroller 全屏点击返回按钮 时 func playerViewController(_ playerViewController: AVPlayerViewController, willEndFullScreenPresentationWithAnimationCoordinator coordinator: UIViewControllerTransitionCoordinator) 没有执行

it seems that video toolbox in ios26 is having trouble decoding h.264 streams I have filed a bug report under https://feedbackassistant.apple.com/feedback/20741484

Is there sample code on how to use VTFrameProcessorOpticalFlow?

Does videotoolbox hevc encoder on iphone16 pro encode with 10bit hdr vui info in bitstream ? I want to encode 4k 10bit hdr bitstream with vui info use hevc videotoolbox .but I don't know how to encode vui info in bitstream ? please give me some sample code ?

context:Explore low-latency video encoding with VideoToolbox https://developer.apple.com/videos/play/wwdc2021/10158/ I see above post said HEVC VideoToolbox can support SVC, temporal layering of streams in low-latency mode with all P frames. my question is that Does HEVC VideoToolbox support temporal layering of streams with B-frames ?? thanks

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?

Hi everyone, I am currently on MacOS Tahoe (26.1), and for some weird reason my mac is not connecting via HDMI. To be accurate: it is connecting and the LG TV shows up in the Displays settings, but no image shows up in it, I have no idea why. This used to work as I've tried this cable before with the same exact tv. The cable is a basic Amazon Basics HDMI one. Allow me just to advanced this question a little: usually terminal commands are more advanced recommendations, whereas basic questions like "have you connected it right" are just a waste of time

SBS ViewPacking add a half a frame to the opposite eye. Meaning if you look all the way right you can see an extra half frame with left eye and vice versa. OU doesn't work at all, the preview just doesn't show a thumbnail and the video doesn't play. Any hints on how to fix this? I submitted a bug report but haven't heard anything.

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!

I'm at my wit's end with a problem I'm facing while developing an app. The app is designed to send video captured on an iPhone to a browser application for real-time display. While it works on many older iPhone models, whenever I test it on an iPhone 17 Pro or 17 Pro Max, the video displayed in the browser becomes a solid green screen, or a colorful, garbled image that's mostly green. I've been digging into this, and my main suspicion is an encoding failure. It seems the resolution of the ultra-wide and telephoto cameras was significantly increased on the 17 Pro and Pro Max (from 12MP to 48MP), and I think this might be overwhelming the encoder. I'm really hoping someone here has encountered a similar issue or has any suggestions. I'm open to any information or ideas you might have. Please help! Environment Information: WebRTC Library: GoogleWebRTC Version 1.1 (via CocoaPods) Signaling Server: AWS Kinesis Video Streams Problem Occurs on: Model: iPhone18,1, OS: 26.0 Model: iPhone18,1, OS: 26.1 Works Fine on: Many models before iPhone17,5 Model: iPhone18,1, OS: 26.0 Model: iPhone18,3, OS: 26.0

We build mobile apps for creators to edit their videos. Post editing the video, the creator has to export the video so that it can be uploaded to Youtube. The export is a time consuming and GPU intensive process. The creator can exit the app due to various reasons like receiving the call, putting the app in background etc. This causes the export to fail :( Keeping this limitation in mind there was an announcement from Apple that with the IOS 26 launch would start to support background GPU access. Here is the official documentation: https://developer.apple.com/documentation/BundleResources/Entitlements/com.apple.developer.background-tasks.continued-processing.gpu When we tried using this feature, we were not able to get it to work on IOS 26. We stumbled upon this ticket(https://developer.apple.com/forums/thread/797538?answerId=854825022#854825022) in the Apple Developer forum, in which possibly an Apple engineer claims it is supported ONLY for iPadOS 26. This is a very big bummer for us. 96% of the users are on iPhone(compared to iPad), and if we refer to the official documentation above, it claims that this feature should work on IOS 26. This feature is extremely important for having the best user experience and reducing user frustration and will be useful for other video editing apps. Looking forward to a resolution.

Currently, I am using the Broadcast UploadExtension function to obtain samplebuffer data through APP Group and IPC (based on the local Unix Domain Socket) The screen recording data transmission method of the domain socket is transmitted to the APP. However, when the APP goes back to the background to view videos in the album or other audio and video, the data transmission stops and the APP cannot obtain the screen recording data. I would like to ask how to solve this problem. I suspect that the system has suspended the extended screen recording

Since iOS/iPadOs/tvOS 18 then we have run into a new problem with streaming of FairPlay encrypted video. On the affected streams then the audio plays perfectly but the video freezes for periods of a few seconds, so it will freeze for 5s or so, then be OK for a few seconds then freeze again. It is entirely reproducible when all the following are true the video streams were produced by a particular encoder (or particular settings, not sure on that) the video must be encrypted device is running some variety of iOS 18 (or iPadOS or tvOS) the device is an affected device Known devices are AppleTV 4K 2nd Gen iPad Pro 11" 1st and 2nd gen Devices known not to show the problem are all other AppleTV models iPhone 13 Pro and 16 Pro If we stream the same content, but unencrypted, then it plays perfectly, or if you play the encrypted stream on, say, tvOS 17. When the freezing occurs then we can see in the console logs repeating blocks of lines like the following default 18:08:46.578582+0000 videocodecd AppleAVD: AppleAVDDecodeFrameResponse(): Frame# 5771 DecodeFrame failed with error 0x0000013c default 18:08:46.578756+0000 videocodecd AppleAVD: AppleAVDDecodeFrameInternal(): failed - error: 316 default 18:08:46.579018+0000 videocodecd AppleAVD: AppleAVDDecodeFrameInternal(): avdDec - Frame# 5771, DecodeFrame failed with error: 0x13c default 18:08:46.579169+0000 videocodecd AppleAVD: AppleAVDDisplayCallback(): Asking fig to drop frame # 5771 with err -12909 - internalStatus: 315 also more relevant looking lines: default 18:17:39.122019+0000 kernel AppleAVD: avdOutbox0ISR(): FRM DONE (cid: 2.0, fno: 10970, codecT: 1) FAILED!! default 18:17:39.122155+0000 videocodecd AppleAVD: AppleAVDDisplayCallback(): Asking fig to drop frame # 10970 with err -12909 - internalStatus: 315 default 18:17:39.122221+0000 kernel AppleAVD: ## client[ 2.0] @ frm 10970, errStatus: 0x10 default 18:17:39.122338+0000 kernel AppleAVD: decodeFailIdentify(): VP error bit 4 has EP3B0 error default 18:17:39.122401+0000 kernel AppleAVD: processHWResponse(): clientID 2.0 frameNumber 10970 error 315, offsetIndex 10, isHwErr 1 So it would seem to me that one of the following must be happening: When these particular HLS files are encrypted then the data is being corrupted in some way that played back on iOS 17 and earlier but now won't on 18+, or There's a regression in iOS 18 that means that this particular format of video data is corrupted on decryption If anyone has seen similar behaviour, or has any ideas how to identify which of the two scenarios it is, please say. Unfortunately we don't have control of the servers so can't make changes there unless we can identify they are definitely the cause of the problem. Thanks, Simon.

Our app plays TS files on an iPhone. The app fragments the TS files, creates an M3U8 playlist, converts them to HLS(HTTP Live Streaming), and then uses AVPlayer to play the video content. On a device running iOS 26, after starting playback and seeking, restarting playback causes the video and audio to be out of sync (by about 2-3 seconds depending on the situation). This also occurs on iPadOS/macOS 26. This issue was not observed prior to iOS 18. We are trying to fix this issue on the app side, but we have the following questions: The behavior of AVPlayer is different between iOS 26 and previous versions. Has there been any change that could be considered? Or is it a bug? We tried pausing before seeking, but it didn’t seem to have any effect. Are there any APIs or workarounds that can improve this? We would appreciate it if you could tell us any other helpful documents or URLs.

(This only started happening as of Xcode 26.) I know macOS and watchOS don't support this property, but all other platforms do (did?) up until I upgraded Xcode. Now when I compile I get this: Value of type 'AVPlayerItem' has no member 'externalMetadata'

Hi, I downloaded and ran https://developer.apple.com/documentation/realitykit/rendering-stereoscopic-video-with-realitykit and noticed that memory usage grows linearly. I replaced the sample video with a different 8k side by side video, and the app crashed almost immediately due to memory leak. it looks like the culprit is from makeMutablePixelBuffer() function and the allocated pixelBuffers are not recycled after being used. screenshot is from a physical device.

Good day. A video I created via iOS AVAssetWriter with the following settings: let videoWriterInput = AVAssetWriterInput( mediaType: .video, outputSettings: [ AVVideoCodecKey: AVVideoCodecType.hevc, AVVideoWidthKey: 1080, AVVideoHeightKey: 1920, AVVideoCompressionPropertiesKey: [ AVVideoAverageBitRateKey: 2_000_000, AVVideoMaxKeyFrameIntervalKey: 30 ], ] ) let audioWriterInput = AVAssetWriterInput( mediaType: .audio, outputSettings: [ AVFormatIDKey: kAudioFormatMPEG4AAC, AVNumberOfChannelsKey: 2, AVSampleRateKey: 44100, AVEncoderBitRateKey: 128000 ] ) When It is split into fMP4 HLS format using ffmpeg, the video is unable to be played in iOS with the following error: CoreMediaErrorDomain error -12848 However, the video is played normally in Android, Browser HLS players, and also VLC Media Player. Please assist. Thank you.

Hello everyone, I'm looking for a definitive clarification on how to completely disable all video stabilization, including the hardware OIS, using AVFoundation. The goal is to achieve a completely raw, unstabilized video feed, which is crucial when using external equipment like gimbals to avoid conflicting stabilization motions. My research points to using the AVCaptureConnection property preferredVideoStabilizationMode and setting it to AVCaptureVideoStabilizationMode.off. The documentation for the .off case states: A mode that doesn’t stabilize video capture. This description is slightly ambiguous. It's unclear whether this only affects software-level stabilization (EIS, EIS+OIS, etc) or if it guarantees the complete deactivation of the physical OIS module. For professional video applications, this is a critical distinction. So, I'd like to ask the community: Has anyone been able to definitively confirm that setting preferredVideoStabilizationMode to .off also disables the hardware OIS? Are there any known tests or documentation that prove this behavior? Is there an alternative or more direct method to ensure the OIS module is physically inactive during video capture? What is the community's best practice for ensuring absolutely no stabilization is applied to the video pipeline? Any insights or shared experiences on this topic would be greatly appreciated. Thank you!

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.