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.

Hey everyone, I'm stuck on a really frustrating AVFoundation problem. I'm building a video editor that uses a custom AVVideoCompositor to add effects, and I need the final output to be 60 FPS. So basically, I create an AVMutableComposition to sequence my video clips. I create an AVMutableVideoComposition and set the frame rate to 60 FPS: videoComposition.frameDuration = CMTime(value: 1, timescale: 60) I assign my CustomVideoCompositor class to the videoComposition. I create an AVPlayerItem with the composition and video composition. The Problem: Playback Works: When I play the AVPlayerItem in an AVPlayer, it's perfect. It plays at a smooth 60 FPS, and my custom compositor's startRequest method is called 60 times per second. Export Fails: When I try to export the exact same composition and video composition using AVAssetExportSession, the final .mp4 file is always 30 FPS (or 29.97). I've logged inside my custom compositor during the export, and it's definitely being called 30 times per second, so it's generating the 30 frames. It seems like AVAssetExportSession is just dropping every other frame when it encodes the video. My source videos are screen recordings which I recorded using ScreenCaptureKit itself with the minimum frame interval to be 60. Here is my export function. I'm using the AVAssetExportPresetHighestQuality preset :- func exportVideo(to outputURL: URL) async throws { guard let composition = composition, let videoComposition = videoComposition else { throw VideoCompositionError.noValidVideos } try? FileManager.default.removeItem(at: outputURL) guard let exportSession = AVAssetExportSession( asset: composition, presetName: AVAssetExportPresetHighestQuality // Is this the problem? ) else { throw VideoCompositionError.trackCreationFailed } exportSession.outputFileType = .mp4 exportSession.videoComposition = videoComposition // This has the 60fps setting try await exportSession.export(to: outputURL, as: .mp4) } I've created a bare bones sample project that shows this exact bug in action. The resulting video is 60fps during playback, but only 30fps during the export. https://github.com/zaidbren/SimpleEditor My Question: Why is AVAssetExportSession ignoring my 60 FPS frameDuration and defaulting to 30 FPS, even though AVPlayer respects it?

When trying to record ProRes RAW (btp2) with AVAssetWriter I get several types of errors: -12780 or -11875. I wonder if recording ProRes RAW can only be done through AVCaptureMovieFileOutput, or if there a way to correctly configure AVAssetWriter to do it.

Adding both AVCaptureMovieFileOutput and AVCaptureVideoDataOutput is supported in AVCaptureSession as seen in documentation (copied snippet below) but then when AVCaptureDevice is configured with ProRes422 codec, it fails unless one of the two outputs is removed from the capture session. It is very much reproducible on iPhone 14 pro running iOS 26.0. Prior to iOS 16, you can add an AVCaptureVideoDataOutput and an AVCaptureMovieFileOutput to the same session, but only one may have its connection active. If you attempt to enable both connections, the system chooses the movie file output as the active connection and disables the video data output’s connection. For apps that link against iOS 16 or later, this restriction no longer exists.

Playback of any kind of HD H.264 MP4 files (720p, 50fps) could randomly cause a stalled image. Playback does not stop in such a case. Image is frozen/stalled. Audio goes on. Timeline goes on. By tapping play/pause or scrubbing in the timeline, the playback recovers. It could also happen, if you are scrubbing in the timeline, especially to areas not loaded already (progressive MP4 download). Behaviour is always the same: image is stalled/frozen, audio goes on. To reproduce: use example project https://developer.apple.com/documentation/AVKit/playing-video-content-in-a-standard-user-interface Example file: https://www.keepinmind.info/test.mp4

I’m building a macOS video editor that uses AVComposition and AVVideoComposition. Initially, my renderer creates a composition with some default video/audio tracks: @Published var composition: AVComposition? @Published var videoComposition: AVVideoComposition? @Published var playerItem: AVPlayerItem? Then I call a buildComposition() function that inserts all the default video segments. Later in the editing workflow, the user may choose to add their own custom video clip. For this I have a function like: private func handlePickedVideo(_ url: URL) { guard url.startAccessingSecurityScopedResource() else { print("Failed to access security-scoped resource") return } let asset = AVURLAsset(url: url) let videoTracks = asset.tracks(withMediaType: .video) guard let firstVideoTrack = videoTracks.first else { print("No video track found") url.stopAccessingSecurityScopedResource() return } renderer.insertUserVideoTrack(from: asset, track: firstVideoTrack) url.stopAccessingSecurityScopedResource() } What I want to achieve is the same behavior professional video editors provide, after the composition has already been initialized and built, the user should be able to add a new video track and the composition should update live, meaning the preview player should immediately reflect the changes without rebuilding everything from scratch manually. How can I structure my AVComposition / AVMutableComposition and my rendering pipeline so that adding a new clip later updates the existing composition in real time (similar to Final Cut/Adobe Premiere), instead of needing to rebuild everything from zero? You can find a playable version of this entire setup at :- https://github.com/zaidbren/SimpleEditor

I want to confirm if this is a bug or a programming error. Very easy to reproduce it by modifying AVCam sample code. Steps to reproduce: Add AVCaptureVideoDataOutput to AVCaptureSession, no need to set delegate in AVCam sample code (CaptureService actor) private let videoDataOutput = AVCaptureVideoDataOutput() and then in configureSession method, add the following line try addOutput(videoDataOutput) if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) { videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_420YpCbCr8BiPlanarFullRange] } And next modify set HDR method: /// Sets whether the app captures HDR video. func setHDRVideoEnabled(_ isEnabled: Bool) { // Bracket the following configuration in a begin/commit configuration pair. captureSession.beginConfiguration() defer { captureSession.commitConfiguration() } do { // If the current device provides a 10-bit HDR format, enable it for use. if isEnabled, let format = currentDevice.activeFormat10BitVariant { try currentDevice.lockForConfiguration() currentDevice.activeFormat = format currentDevice.unlockForConfiguration() isHDRVideoEnabled = true if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange) { videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange] } } else { captureSession.sessionPreset = .high isHDRVideoEnabled = false if videoDataOutput.availableVideoPixelFormatTypes.contains(kCVPixelFormatType_32BGRA) { print("Setting sdr pixel format \(kCVPixelFormatType_32BGRA)") videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : kCVPixelFormatType_32BGRA] } try currentDevice.lockForConfiguration() currentDevice.activeColorSpace = .sRGB currentDevice.unlockForConfiguration() } } catch { logger.error("Unable to obtain lock on device and can't enable HDR video capture.") } The problem now is toggling HDR on and off no longer works in video mode. If after setting HDR on, you set HDR to off, active format of device does not change (setting sessionPreset has no effect). This does not happen if video data output is not added to session. Is there any workaround available?

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.

Avplayer encapsulates a player. After connecting to an Apple Bluetooth headset, it immediately reports an error. Non-Apple Bluetooth headsets can be played, but currently the issue is that the player works normally in one app but not in another. We are an educational app.

Hello, I requested Fairplay credentials a week ago. Where can I check the status of my request? Thank you very much. The team ID is: 6WZ8SVRYV9

We’re developing an AVFoundation-based video recording app (4K @ 60 fps required for biomechanical analysis). On most devices this works perfectly (iPhone 12/14/15/16 non-Pro models), but on several iPhone Pro models (12 Pro, 13 Pro, 14 Pro, 15 Pro/Pro Max), we consistently get 4K 30 fps recordings—even when the device should support 4K 60 fps on the wide-angle camera. What we observe We configure the session for .hd4K3840x2160. We iterate through AVCaptureDevice.formats and select formats that: have 3840×2160 resolution support ≥60 fps (videoSupportedFrameRateRanges) On some Pro devices, this format search returns no results, even though: The Camera app records 4K60 fine. External references list the wide camera as 4K60 capable. The fallback becomes the device's default 4K30 format, so final files are 3840×2160 @ 30 fps. This happens immediately on app launch (not after heating), so not thermal-related. What we’ve tried Force selecting .builtInWideAngleCamera instead of dual/triple cameras. Disabling HDR (videoHDREnabled = false). Disabling low-light boost. Allowing 59.94 fps formats (in case exact 60.0 isn’t exposed). Logging all videoSupportedFrameRateRanges per format. What we’re seeing in logs On affected Pro devices, the capture device reports only 4K formats with maxFrameRate ≈ 30 fps, despite the hardware being able to do 4K60. Main question Has anyone encountered cases where 4K60 formats are available in the Camera app but not exposed through AVFoundation, especially on Pro models or multi-camera devices? Could HEVC/HDR capability or multi-camera constraints be preventing certain formats from appearing? Are there known conditions where 4K60 formats are hidden unless specific device configuration is applied? Any guidance on reliably locking 4K60 on iPhone Pro models via AVFoundation would be hugely appreciated.

I have found that following code runs without issue from Xcode, either in Debug or Release mode, yet crashes when running from the binary produced by archiving - i.e. what will be sent to the app store. import SwiftUI import AVKit @main struct tcApp: App { var body: some Scene { WindowGroup { VideoPlayer(player: nil) } } } This is the most stripped down code that shows the issue. One can try and point the VideoPlayer at a file and the same issue will occur. I've attached the crash log: Crash log Please note that this was seen with Xcode 26.2 and MacOS 26.2.

Facing an issue with audio playback using AVPlayerViewController in iOS application. We are using the native player to play recorded audio files. When the AVPlayerViewController appears, the native user interface is displayed correctly, including the playback controls and the volume slider. However, when the user interacts with the volume slider The slider UI moves and responds to touch events. The actual audio output volume does not change. The audio continues playing at the initial volume level regardless of the slider position. We initialize the player and present it modally using the following code: AVPlayerViewController *avController = [[AVPlayerViewController alloc] init]; avController.player = [AVPlayer playerWithURL:videoURL]; // Setting initial volume avController.player.volume = 1.0f; avController.modalPresentationStyle = UIModalPresentationOverFullScreen; avController.allowsPictureInPicturePlayback = NO; // Present the controller [self presentViewController:avController animated:YES completion:nil];

Has anyone tried to make an ILPD based AIME file? When I try the resulting AIME switches to USDZ Mesh instead of saving the ILPD Data.

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'.