Short summary When setting exposureMode to .locked or .custom the brightness of a video stream still changes depending on the composition and contrast of the visible scene. These changes seem to come from contrast enhancements or dynamic range optimizations and totally break any analysis of the image that requires to assess absolute luminance. While exposure lock seems to indeed lock the physical exposure parameters of the camera (shutter speed and ISO), I cannot find any way to control these "soft" modifiers. Details Background I am the developer of the app "phyphox", an educational app that makes the phone's sensors accessible to students as measurement tools in science experiments. Currently I am working on implementing photometric measurements through the camera and one very important aspect of it is luminance measurements. This is particularly relevant since the light sensor of the phone has no publicly accessible API and the camera could to some extend make experiments available to Apple users that are otherwise only possible on Android devices. Implementation The app uses AVFoundation and explicitly picks individual cameras since camera groups do not support custom exposure settings. This means that it handles camera switching during zoom by itself and even implements its own auto exposure routines to optimize for the use in experiments. Therefore it always stays in custom exposure mode. The app uses YUV420 color space and the individual frames are analyzed in Metal using compute shaders. However, the effects discussed here still occur if I remove all code to control the camera and replace it with a simple sequence of setting the exposure mode to custom, setting custom exposure values, setting a fixed white balance and then setting the exposure mode to locked as suggested on stackoverflow. This neither helps on an iPhone 14 Pro nor on an iPhone 8 despite a report on the developer forums that it would resolve the issue for older devices. The app is open source, so the code can be seen in our current development branch (without the changes for the tests here, though) on github. The videos below use the implementation with the suggestion from stackoverflow, but they can be reproduced in the same way with "professional" camera apps that promise manual control over the camera (like the Blackmagic cam to quote a reputable company) as well as the stock camera app after pressing and holding on the preview to enable AE/AF lock. Demonstration These examples were captured on an iPhone 14 Pro. The central part of the image (highlighted by the app using metal shaders after capture) should not change with fixed exposure settings, but significant changes are noticable if there are changes at the edge of the frame when I move a black piece of cardboard in from above: https://share.icloud.com/photos/0b1f_3IB6yAQG-qSH27pm6oDQ The graph above the camera preview is the average luminance (gamma corrected and weighted based on sRGB) across the highlighted central area and as mentioned before it should not change because of something happening at the side of the frame (worst case it should get a bit darker because of the cardboard's shadow). In my opinion, the iPhone changes its mind on the ideal contrast as soon as it has a different exposure histogram because of the dark image part from the cardboard, but that's just me guessing. For completeness here is the same effect in the stock camera app with AE/AF lock enabled: https://share.icloud.com/photos/0cd7QM8ucBZKwPwE9mybnEowg Here you can also see that the iPhone "ramps" the changes. The brightness of the gray area does not change immediately but transitions smoothly, so this is clearly deliberate postprocessing. So... Any suggestion on how to prevent this behavior would be highly appreciated.

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)

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

I’m using ScreenCaptureKit on macOS to grab frames and measure end-to-end latency (capture → my delegate callback). For each CMSampleBuffer I read: let pts = CMSampleBufferGetPresentationTimeStamp(sampleBuffer).seconds to get the “capture” timestamp, and I also extract the mach-absolute display time: let attachments = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, createIfNecessary: false) as? [[SCStreamFrameInfo: Any]] let displayMach = attachments?.first?[.displayTime] as? UInt64 // convert mach ticks to seconds... Then I compare both against the current time: let now = CACurrentMediaTime() let latencyFromPTS = now - pts let latencyFromDisplay = now - displayTimeSeconds But I consistently see negative values for both calculations—i.e. the PTS or displayTime often end up numerically larger than now. This suggests that the “presentation timestamp” and the mach-absolute display time are coming from a different epoch or clock domain than CACurrentMediaTime(). Questions: Which clocks/epochs does ScreenCaptureKit use for PTS and for .displayTime? How can I align these timestamps with CACurrentMediaTime() so that now - pts and now - displayTime reliably yield non-negative real-world latencies? Any pointers on the correct clock conversions or APIs to use would be greatly appreciated.

When I play an HDR video in the iPhone Photos app, I can see the HDR effect obviously. But if this HDR video is played continuously for more than 30-40 minutes, the HDR effect will disappear and the brightness will be compressed to the SDR range. This issue will appear on any iPhone. Depending on the phone, it may be 20-30 minutes, or 30-40 minutes, or even a few minutes, such as iPhone 12 mini. Similarly, if I use AVPlayer to play and preview an HDR video, if it plays more than 30-40 minutes, the HDR effect will disappear and the screen brightness will dim. Also the currentEDRHeadroom will gradually decrease to 1 Note, test it with an HDR video longer than 1 hour, and if the video is short, please loop it. My question is how to avoid losing the HDR effect after 30-40 minutes when I use CAMetalLayer to render any HDR video.

I use replaykit for system-level screen recording. I want to determine whether the screen is in landscape mode by calling back CMSamplebuffer, but CMSamplebuffer does not come with this information. The other several apis related to obtaining the screen orientation are also restricted by the background. I want to know whether the information of the screen rotation direction can be obtained in real time in the background

Hi All. I'm working on Single-Sign-On feature in my application to let customers sign into their TV Provider. I need to add Video Subscriber SSO entitlement (com.apple.developer.video-subscriber-single-sign-on) to the app, but I found out that it's a special entitlement, need to contact Apple to enable it for my Apple account. On https://developer.apple.com/account I navigated to Support -> Contact Us -> Development and Technical -> Entitlements and ask in the email about missing entitlement (ticket ID 102478794279). The support team couldn't help me, they redirected me to the operations team. I've been waiting for a few months now but they inform me to keep waiting. Is there a better way to contact Apple and get Video Subscriber SSO entitlement in an efficient way?

I have beet taking images from the iOS video camera feed and have encountered an issue. When you take images form the wideCamera this consumes about half the phone's CPU. The same is not the case when you take images from the telephotoCamera video stream. Is there a way of disabling the extra processing that is being done?

Hello, I'm Soonwon. We’re currently developing a UVC camera device and trying to stream MJPEG video via AVFoundation on macOS. However, we’re running into a problem with custom resolutions. When we try to use AVFoundation on macOS to capture MJPEG video at 1000x6000, the stream is not accepted or simply doesn’t work. Lower resolutions work fine. (Interestingly, using the same device on iPadOS, we can capture the 1000x6000 MJPEG stream successfully by using AVCaptureSessionPresetInputPriority.) Is there any way to receive custom-resolution MJPEG streams (like 1000x6000) from a UVC device using AVFoundation on macOS? Are there specific session presets, entitlements, or known limitations that affect MJPEG handling at custom resolutions on macOS? Does macOS handle MJPEG differently from iPadOS in AVFoundation? Any insight or guidance would be greatly appreciated. Thank you! NSError *error = nil; if ([selectedDevice lockForConfiguration:&error]) { [session beginConfiguration]; session.sessionPreset = AVCaptureSessionPresetHigh; bool foundFormat = false; for (AVCaptureDeviceFormat *format in selectedDevice.formats) { CMVideoDimensions dims = CMVideoFormatDescriptionGetDimensions(format.formatDescription); FourCharCode pixelFormat = CMFormatDescriptionGetMediaSubType(format.formatDescription); foundFormat = true; if (dims.width == 1000 && dims.height == 6000) { selectedDevice.activeFormat = format; foundFormat = true; break; } } if(foundFormat == false) { NSLog(@"Failed to foundFormat : "); [session commitConfiguration]; return false; } NSError* error = nil; AVCaptureDeviceInput* input = [AVCaptureDeviceInput deviceInputWithDevice:selectedDevice error:&error]; if (error || ![session canAddInput:input]) { NSLog(@"Failed to add video input: %@", error.localizedDescription); [session commitConfiguration]; return false; } [session addInput:input]; AVCaptureVideoDataOutput* output = [[AVCaptureVideoDataOutput alloc] init]; output.alwaysDiscardsLateVideoFrames = YES; output.videoSettings = @{ (NSString*)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange) }; [output setSampleBufferDelegate:delegate queue:queue]; if ([session canAddOutput:output]) { [session addOutput:output]; } [session commitConfiguration]; [selectedDevice unlockForConfiguration]; } else { NSLog(@"Failed to lock device for configuration: %@", error.localizedDescription); } // start~

I would like to play videos in webM format on my iPhone. I understand that it is basically impossible to play videos in webM format on an iPhone, but is there any way to display videos in webM format? I would like to know if there is an official Swift SDK or development kit released by Apple. Or if there are any third-party products, please let me know.

Recurring crash on install of any app with the new sourceVideoTrackProvider.next() dyld[41966]: Symbol not found: _$sSo19AVAssetReaderOutputC12AVFoundationE8ProviderC4nextxSgyYaKFTjTu Referenced from: <79AA2BE0-A6B4-32F5-A804-E84BBE5D1AEA> /Users/<username>/Library/Developer/Xcode/DerivedData/TrackProviderCrash-bbbhjptcxnmfdcackxtpucnunxyc/Build/Products/Debug-maccatalyst/TrackProviderCrash.app/Contents/MacOS/TrackProviderCrash.debug.dylib Expected in: <1B847AF9-7973-3B28-95C2-09E73F6DD50B> /usr/lib/swift/libswiftAVFoundation.dylib Can be reproduced with the current Xcode Beta 4 by running on to MacCatalyst and macOS https://developer.apple.com/documentation/AVFoundation/converting-projected-video-to-apple-projected-media-profile Crash goes away of you comment out lines 154-158 and 164-170 which are while let sampleBuffer = try await sourceVideoTrackProvider.next(){/*other code*/} Can also be reproduced if you add the code below to a MacCatalyst project import AVKit let asset: AVURLAsset = .init(url: Bundle.main.url(forResource: "SomeVideo.mp4", withExtension: nil)!) let videoReader = try! AVAssetReader(asset: asset) let videoTracks = try! await asset.loadTracks(withMediaCharacteristic: .visual) // Get the side-by-side video track. let videoTrack = videoTracks.first! let videoInputTrack = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: nil) let sourceVideoTrackProvider: AVAssetReaderOutput.Provider<CMReadySampleBuffer<CMSampleBuffer.DynamicContent>> = videoReader.outputProvider(for: videoInputTrack) //Comment out this while let sb = try! await sourceVideoTrackProvider.next() { }

One thing I've noticed on tvOS 26 is that if you try to set the AVPlayerViewController customInfoViewControllers property while the Content Tabs are on screen, your app will crash. *** Terminating app due to uncaught exception 'UIViewControllerHierarchyInconsistency', reason: 'trying to add child view controller that is already presented: <AVInfoPanelViewController: 0x1030cdc00>' *** First throw call stack: (0x18a7167bc 0x189a77510 0x18a7166a8 0x1ab425658 0x1b2ee9d54 0x1b2efcd60 0x1b2eaf3f0 0x1080f744c 0x107e021a8 0x107e01b3c 0x18de41c14 0x18de41ba8 0x18de48d28 0x18ad9e358 0x101fac5f0 0x101fc6228 0x101fe7278 0x101fbc6fc 0x101fbc63c 0x18a67a2e0 0x18a679418 0x18a673b34 0x1937e4d5c 0x1abb36588 0x1abb3ae80 0x1aae9dec4 0x108610174 0x1086100e4 0x108615140 0x189abd4d0) I've logged a feedback (FB19554461) but it's getting awfully late in the dev cycle. So I've been trying to think of a workaround. The problem is that customInfoViewControllers is pretty declarative in nature. There are no properties or delegate methods I am aware of that let me know when they are displaying or not. One trick I came up with was seeing if my custom info view controller's view was "visible" or not - I put that in quotes because it turns out it can be visible even when I think it's not, as when the transport bar is scrolled to the top my custom VC still has its top pixels showing, so it gets a viewDidAppear call. So, I tried to see if my view controllers view is completely visible, ie based on the results of the GGRect contains method. And that works! But the problem is it only accounts for my own custom info view controllers, and not the standard one that Apple provides. I can't think of a way at all to know whether that is showing. Any ideas?

Any one experience this bug, when playing a video the bluetooth headphones loose audio? my workaround is to select from one of the other audio outputs, and go back again and select the affected headphone.

Hi there, I want to set the iphone camera to "S mode, or Shutter Priority" in camera terminology. Which is a semi-auto exposure model with shutter speed fixed, or set manually. However, when setting the shutter speed manually, it disables the auto exposure. So is there a way to keep the auto exposure on while restrict the shutter speed? Also, I would like to keep a low frame rate, e.g. 30 fps. Would I be able to set shutter speed independent of frame rate? Here's the code for setting up the camera Best,

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.

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.

Hi, trying to wrap my head around Xcode's FXPlug. I already sell Final Cut Pro titles for a company. These titles were built in motion. However, they want me to move them to an app and I'm looking for any help on how to accomplish this *What the app should do is: Allow users with an active subscription to our website the ability to access titles within FCPX and if they are not an active subscriber, for access to be denied.

I have generated FCPXML, but i can't figure out issue: <?xml version="1.0"?> <fcpxml version="1.11"> <resources> <format id="r1" name="FFVideoFormat3840x2160p2997" frameDuration="1001/30000s" width="3840" height="2160" colorSpace="1-1-1 (Rec. 709)"/> <asset id="video0" name="11a(1-5).mp4" start="0s" hasVideo="1" videoSources="1" duration="6.81s"> <media-rep kind="original-media" src="file:///Volumes/Dropbox/RealMedia Dropbox/Real Media/Media/Test/Test AE videos, City, testOLOLO/video/11a(1-5).mp4"/> </asset> <asset id="video1" name="12(4)r8 mute.mp4" start="0s" hasVideo="1" videoSources="1" duration="9.94s"> <media-rep kind="original-media" src="file:///Volumes/Dropbox/RealMedia Dropbox/Real Media/Media/Test/Test AE videos, City, testOLOLO/video/12(4)r8 mute.mp4"/> </asset> <asset id="video2" name="13 mute.mp4" start="0s" hasVideo="1" videoSources="1" duration="6.51s"> <media-rep kind="original-media" src="file:///Volumes/Dropbox/RealMedia Dropbox/Real Media/Media/Test/Test AE videos, City, testOLOLO/video/13 mute.mp4"/> </asset> <asset id="video3" name="13x (8,14,24,29,38).mp4" start="0s" hasVideo="1" videoSources="1" duration="45.55s"> <media-rep kind="original-media" src="file:///Volumes/Dropbox/RealMedia Dropbox/Real Media/Media/Test/Test AE videos, City, testOLOLO/video/13x (8,14,24,29,38).mp4"/> </asset> </resources> <library> <event name="Untitled"> <project name="Untitled Project" uid="28B2D4F3-05C4-44E7-8D0B-70A326135EDD" modDate="2024-04-17 15:44:26 -0400"> <sequence format="r1" duration="4802798/30000s" tcStart="0s" tcFormat="NDF" audioLayout="stereo" audioRate="48k"> <spine> <asset-clip ref="video0" offset="0/10000s" name="11a(1-5).mp4" duration="0/10000s" format="r1" tcFormat="NDF"/> <asset-clip ref="video1" offset="12119/10000s" name="12(4)r8 mute.mp4" duration="0/10000s" format="r1" tcFormat="NDF"/> <asset-clip ref="video2" offset="22784/10000s" name="13 mute.mp4" duration="0/10000s" format="r1" tcFormat="NDF"/> <asset-clip ref="video3" offset="34544/10000s" name="13x (8,14,24,29,38).mp4" duration="0/10000s" format="r1" tcFormat="NDF"/> </spine> </sequence> </project> </event> </library> </fcpxml> Any ideas?

I am developing an iOS app that uses YOLOv8 for object detection and aims to detect objects at 60 FPS using the UltraWide camera. My goal is to process every frame within captureOutput and utilize the detected data (such as coordinates) for each one. I have a question regarding how background thread processing behaves in this scenario. Does the size of the YOLO model (n, s, m, etc.) or the weight of the operations inside captureOutput affect the number of frames that can be successfully processed? Specifically, I would like to know if all frames will be processed sequentially with a delay due to heavy processing in the background, or if some frames will be dropped and not processed at all. Any insights on how to handle this would be greatly appreciated. Thank you!

I think I have the simplest possible Mac app trying to see if I can have VideoPlayer work in an Xcode Preview. It works in an iOS app project. In a Mac app project it builds and runs. But if I preview in Xcode it crashes. The diagnostic says: | [Remote] Unknown Error: The operation couldn’t be completed. XPC error received on message reply handler | | BSServiceConnectionErrorDomain (3): | ==NSLocalizedFailureReason: XPC error received on message reply handler | ==BSErrorCodeDescription: OperationFailed The code I'm using is the exact code from the VideoPlayer documentation page. See this link. Any ideas about this XPC error, and how to work around? I'm using Xcode 16.0 on macOS 14.6.1