Photos & Camera

RSS for tag

Explore technical aspects of capturing high-quality photos and videos, including exposure control, focus modes, and RAW capture options.

Posts under Photos & Camera subtopic

Post

Replies

Boosts

Views

Activity

AVCaptureSession preview briefly goes blank after interruption (lock/unlock or camera switch) while isRunning == true
Environment Device: iPhone 15 Pro iOS: iOS 18.0 Framework: AVFoundation App type: Custom camera app using AVCaptureSession + AVCaptureVideoPreviewLayer I’m seeing an intermittent but frequent issue where the camera preview layer briefly flashes empty after certain interruptions, even though the capture session reports itself as running and no errors are emitted. This happens most often after: Locking and unlocking the device Switching cameras (back ↔ front) The issue is not 100% reproducible, but occurs often enough to be noticeable in normal usage. What happens The preview layer briefly flashes as empty (sometimes just a “micro-frame”) Duration: typically ~0.5–2 seconds before frames resume session.isRunning == true throughout No crash, no runtime error, no interruption end failure Focus/exposure restore correctly once frames resume Visually it looks like the preview layer loses frames temporarily, even though the session appears healthy. Repro Intermittent but frequent after: Lock → unlock device Switching camera (front/back) Timing-dependent and non-deterministic Happens multiple times per session, but not every time Key observation AVCaptureSession.isRunning == true does not guarantee that frames are actually flowing. To verify this, I added an AVCaptureVideoDataOutput temporarily: During the blank period, no sample buffers are delivered Frames resume after ~1–2s without any explicit restart Session state remains “running” the entire time What I’ve tried (did NOT fix it) Adding delays before/after startRunning() (0.1–0.5s) Calling startRunning() on different queues Restarting the session in AVCaptureSessionInterruptionEnded Verifying session.connections (all show isActive == true) Rebuilding inputs/outputs during interruption recovery Ensuring startRunning() is never called between beginConfiguration() / commitConfiguration() (Hit the expected runtime warning when attempted) None of the above removed the brief blank preview. Workaround (works visually but expensive) This visually fixes the issue, but: Energy impact jumps from Low → High in Xcode Energy Gauge AVCaptureVideoDataOutput processes 30–60 FPS continuously The gap only lasts ~1–2s, but toggling the delegate on/off cleanly is difficult Overall CPU and energy cost is not acceptable for production Additional notes CPU usage is already relatively high even without the workaround (this app is camera-heavy by nature) With the workaround enabled, energy impact becomes noticeably worse The issue feels like a timing/state desync between session state and actual frame delivery, not a UI issue Questions Is this a known behavior where AVCaptureSession.isRunning == true but frames are temporarily unavailable after interruptions? Is there a recommended way to detect actual frame flow resumption (not just session state)? Should the AVCaptureVideoPreviewLayer.connection (isActive / isEnabled) be explicitly checked or reset after interruptions? Is there a lightweight, energy-efficient way to bridge this short “no frames” gap without using AVCaptureVideoDataOutput? Is rebuilding the entire session the only reliable solution here, or is there a better pattern Apple recommends?
1
0
734
1w
Camera Permissions Popup
We have a very strange issue that I am trying to solve or find the best practice for. We have a SwiftUI View that uses the Camera to preview. So as suggested in Apples Docs we check authorisation status and then if it's not determined we request authorisation. We also have the privacy entry in the info.plist case .notDetermined: AVCaptureDevice.requestAccess(for: .video) { accessStatusAuthorised in if !accessStatusAuthorised { self.cameraStatus = .notAuthorised } else { self.isAuthorized = true self.cameraStatus = .authorised self.startCameraSession(cameraPosition: cameraPosition) } } case .restricted: cameraStatus = .notAuthorised isAuthorized = false case .denied: cameraStatus = .notAuthorised isAuthorized = false case .authorized: cameraStatus = .authorised isAuthorized = true startCameraSession(cameraPosition: cameraPosition) break @unknown default: isAuthorized = true cameraStatus = .notAuthorised } However when we call this code it freezes the Camera feed, even when allow has been tapped. However and this is the confusing part. If we do not call the code above, we still get the permission for camera access pop up and the camera works fine after allowing. What im concerned about is changing the code to do this and its a possible apple bug that gets fixed and hey then none of the Apps allow the camera function. I cannot see any where that the process has changed for iOS 26 / Xcode 26. Can anyone shed any light on this or had similar experience ?
1
0
57
1w
Any way to trigger cameraLensSmudgeDetectionStatus to change?
Looking to implement to UI to tell the user to clean their lens in our app. Implemented the KVO for the cameraLensSmudgeDetectionStatus but I'm having issues reliably triggering it in, both in our app and the main camera app. Tried to get inventive by putting tupperware over the lens, but I think the model driving this or the LiDAR sensor might be smart enough to detect there is something close to the lens. Is there any way to trigger this change in a similar way we can trigger thermal changes in debug? Thanks.
1
0
57
1w
dyld[434]: Library not loaded: error when running LockedCameraCapture compatible app on iOS 15
Hello, I am getting the following error while attempting to run my LockedCameraCapture compatible app on an iOS 15 device: dyld[434]: Library not loaded: '/System/Library/Frameworks/LockedCameraCapture.framework/LockedCameraCapture' Referenced from: '/private/var/containers/Bundle/Application/.../MyApp.app/MyApp.debug.dylib' Reason: tried: '/System/Library/Frameworks/LockedCameraCapture.framework/LockedCameraCapture' (no such file) Of course iOS 15 doesn't have the library for LockedCameraCapture, but I have had no issue including Lock Screen Widgets (which require iOS 16), so I am not sure why the error is popping up. Thank you!
2
0
513
Mar ’25
Unable to Capture 24MP Photos
Hello, I'm wondering how to capture 24MP photos. I'm currently testing on an iPhone 16 Pro Max. By default, the device's activeFormat supports 24MP (photo dimensions: {4032x3024, 5712x4284}). For the photoOutput, I'm setting the maxPhotoDimensions to videoDevice.activeFormat.supportedMaxPhotoDimensions.lastObject, and setting MaxPhotoQualityPrioritization to quality. When capturing, I'm applying the same maxPhotoDimensions and photoQualityPrioritization settings from the photoOutput directly to the AVCapturePhotoSettings. What could be the issue? // Objective-C // setup [self.photoOutput setMaxPhotoQualityPrioritization:AVCapturePhotoQualityPrioritizationQuality]; CMVideoDimensions maxPhotoDimensions = [(NSValue *)videoDevice.activeFormat.supportedMaxPhotoDimensions.lastObject CMVideoDimensionsValue]; [self.photoOutput setMaxPhotoDimensions:maxPhotoDimensions]; // capturing AVCapturePhotoSettings *photoSettings = [AVCapturePhotoSettings photoSettings]; photoSettings.maxPhotoDimensions = self.photoOutput.maxPhotoDimensions; photoSettings.photoQualityPrioritization = self.photoOutput.maxPhotoQualityPrioritization; [self.photoOutput capturePhotoWithSettings:photoSettings delegate:photoCaptureDelegate]; ...
2
0
735
1d
Torch Freezes Ultra-Wide Camera When Switching Between Wide & Ultra-Wide Lenses (AVFoundation Bug?)
I'm developing an iOS app using AVFoundation for real-time video capture and object detection. While implementing torch functionality with camera switching (between Wide and Ultra-Wide lenses), I encountered a critical issue where the camera freezes when toggling the torch while the Ultra-Wide camera is active. Issue If the torch is ON and I switch from Wide to Ultra-Wide, the camera freezes If the Ultra-Wide camera is active and I try to turn the torch ON, the camera freezes The iPhone Camera app allows using the torch while recording video with the Ultra-Wide lens, so this should be possible via AVFoundation as well. Code snippet DispatchQueue.global(qos: .userInitiated).async { [weak self] in guard let self = self else { return } let isSwitchingToUltraWide = !self.isUsingFisheyeCamera let cameraType: AVCaptureDevice.DeviceType = isSwitchingToUltraWide ? .builtInUltraWideCamera : .builtInWideAngleCamera let cameraName = isSwitchingToUltraWide ? "Ultra Wide" : "Wide" guard let selectedCamera = AVCaptureDevice.default(cameraType, for: .video, position: .back) else { DispatchQueue.main.async { self.showAlert(title: "Camera Error", message: "\(cameraName) camera is not available on this device.") } return } do { let currentInput = self.videoCapture.captureSession.inputs.first as? AVCaptureDeviceInput self.videoCapture.captureSession.beginConfiguration() if isSwitchingToUltraWide && self.isFlashlightOn { self.forceEnableTorchThroughWide() } if let currentInput = currentInput { self.videoCapture.captureSession.removeInput(currentInput) } let videoInput = try AVCaptureDeviceInput(device: selectedCamera) self.videoCapture.captureSession.addInput(videoInput) self.videoCapture.captureSession.commitConfiguration() self.videoCapture.updateVideoOrientation() DispatchQueue.main.async { if let barButton = sender as? UIBarButtonItem { barButton.title = isSwitchingToUltraWide ? "Wide" : "Ultra Wide" barButton.tintColor = isSwitchingToUltraWide ? UIColor.systemGreen : UIColor.white } print("Switched to \(cameraName) camera.") } self.isUsingFisheyeCamera.toggle() } catch { DispatchQueue.main.async { self.showAlert(title: "Camera Error", message: "Failed to switch to \(cameraName) camera: \(error.localizedDescription)") } } } } Expected Behavior Torch should be able to work when Ultra-Wide is active, just like the iPhone Camera app does. The camera should not freeze when switching between Wide and Ultra-Wide with the torch ON. AVCaptureSession should not crash when toggling the torch while Ultra-Wide is active. Questions & Help Needed Is this a known issue with AVFoundation? How does the iPhone Camera app allow using the torch while recording in Ultra-Wide? What’s the correct way to switch between Wide and Ultra-Wide cameras without freezing when the torch is active? Info Device tested: iPhone 13 Pro / iPhone 15 Pro / Iphone 15 iOS Version: iOS 17.3 / iOS 18.0 Xcode Version: 16.2
2
1
678
Oct ’25
AVCaptureDevice rotationCoordinator modifying CALayer on switching devices
I am trying to use AVCaptureDevice.rotationCoordinator API to observe angles for preview and capture and it seems there is an issue with the API when used with arbitrary CALayer (which is not a AVCaptureVideoPreviewLayer) and switching cameras. Here is my setup. The below function is defined in an actor class called CameraManager that performs setup of rotationCoordinator. func updateRotationCoordinator(_ callback:@escaping @MainActor (CGFloat) -> Void) { guard let device = sessionConfiguration.activeVideoInput?.device, let displayLayer = displayLayer else { return } cancellables.removeAll() rotationCoordinator = AVCaptureDevice.RotationCoordinator(device: device, previewLayer: displayLayer) guard let coordinator = rotationCoordinator else { return } coordinator.publisher(for: \.videoRotationAngleForHorizonLevelPreview) .receive(on: DispatchQueue.main) .sink { degrees in let radians = degrees * .pi / 180 MainActor.assumeIsolated { callback(radians) } } .store(in: &cancellables) } This works the very first time but when I switch cameras and call this function again, it throws a runtime error that view's layer is modified from a non-main thread. This happens at the very line where rotation coordinator is been recreated. It's not clear why initialising rotation coordinator should modify CALayer properties right in it's init method. Modifying properties of a view's layer off the main thread is not allowed: view <MyApp.DisplayLayerView: 0x102ffaf40> with nearest ancestor view controller <_TtGC7SwiftUI19UIHostingControllerGVS_15ModifiedContentVS_7AnyViewVS_12RootModifier__: 0x101f7fb80>; backtrace: ( 0 UIKitCore 0x0000000194a977b4 575E5140-FA6A-37C2-B00B-A4EACEDFDA53 + 22509492 1 UIKitCore 0x000000019358594c 575E5140-FA6A-37C2-B00B-A4EACEDFDA53 + 416076 2 QuartzCore 0x00000001927f5bd8 D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 43992 3 QuartzCore 0x00000001927f5a4c D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 43596 4 QuartzCore 0x000000019283a41c D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 324636 5 QuartzCore 0x000000019283a0a8 D8E8E86D-85AC-3C90-B2E1-940235ECAA18 + 323752 6 AVFCapture 0x00000001af072a18 09192166-E0B6-346C-B1C2-7C95C3EFF7F7 + 420376 7 MyApp.debug.dylib 0x0000000105fa3914 $s10MyApp15CapturePipelineC25updateRotationCoordinatoryyy12CoreGraphics7CGFloatVScMYccF + 972 8 MyApp.debug.dylib 0x00000001063ade40 $s10MyApp11CameraModelC18switchVideoDevicesyyYaFTY3_ + 72 9 MyApp.debug.dylib 0x0000000105fe3cbd $s10MyApp11ContentViewV4bodyQrvg7SwiftUI6VStackVyAE05TupleE0VyAE6HStackVyAIyAE6SpacerV_AE6ButtonVyAE0E0PAEE5frame5width6height9alignmentQr12CoreGraphics7CGFloatVSg_AyE9AlignmentVtFQOyAqEE11scaledToFitQryFQOyAqEE10imageScaleyQrAE5ImageV0Z0OFQOyA3__Qo__Qo__Qo_GtGG_AmKyAIyAKyAIyAqEE7paddingyQrAE4EdgeO3SetV_AYtFQOyAA07CaptureM0V_Qo__AOyAE4TextVGAmKyAIyA9__AqEEArstUQrAY_AYA_tFQOyAM_Qo_A9_tGGtGG_AmqEE10background_AUQrqd___A_tAePRd__lFQOyAqEEArstUQrAY_AYA_tFQOyA21__Qo__AqEEArstUQrAY_AYA_tFQOyAE06_ShapeE0VyAE9RectangleVAE5ColorVG_Qo_Qo_SgtGGtGGyXEfU0_A42_yXEfU_A10_yXEfU_yyScMYccfU_yyYacfU_TQ1_ + 1 10 MyApp.debug.dylib 0x0000000105ff06d9 $s10MyApp11ContentViewV4bodyQrvg7SwiftUI6VStackVyAE05TupleE0VyAE6HStackVyAIyAE6SpacerV_AE6ButtonVyAE0E0PAEE5frame5width6height9alignmentQr12CoreGraphics7CGFloatVSg_AyE9AlignmentVtFQOyAqEE11scaledToFitQryFQOyAqEE10imageScaleyQrAE5ImageV0Z0OFQOyA3__Qo__Qo__Qo_GtGG_AmKyAIyAKyAIyAqEE7paddingyQrAE4EdgeO3SetV_AYtFQOyAA07CaptureM0V_Qo__AOyAE4TextVGAmKyAIyA9__AqEEArstUQrAY_AYA_tFQOyAM_Qo_A9_tGGtGG_AmqEE10background_AUQrqd___A_tAePRd__lFQOyAqEEArstUQrAY_AYA_tFQOyA21__Qo__AqEEArstUQrAY_AYA_tFQOyAE06_ShapeE0VyAE9RectangleVAE5ColorVG_Qo_Qo_SgtGGtGGyXEfU0_A42_yXEfU_A10_yXEfU_yyScMYccfU_yyYacfU_TATQ0_ + 1 11 MyApp.debug.dylib 0x0000000105f9c595 $sxIeAgHr_xs5Error_pIegHrzo_s8SendableRzs5NeverORs_r0_lTRTQ0_ + 1 12 MyApp.debug.dylib 0x0000000105f9fb3d $sxIeAgHr_xs5Error_pIegHrzo_s8SendableRzs5NeverORs_r0_lTRTATQ0_ + 1 13 libswift_Concurrency.dylib 0x000000019c49fe39 E15CC6EE-9354-3CE5-AF91-F641CA8283E0 + 433721 )
2
0
585
Feb ’25
Does PHAsset localIdentifier change after device transfer?
Hi, I’m working on a photo backup app. I track the PHAsset localIdentifier to determine which photos have been backed up and which haven’t. Recently, I’ve noticed that two users seem to have experienced the localIdentifier changes after transferring data to a new iPhone using Quick Start. Additionally, others on StackOverflow have mentioned that the localIdentifier sometimes changes after updating the iOS version. https://stackoverflow.com/questions/40094728/phobject-localidentifier-reliability I’d like to confirm the reliability of the localIdentifier after an iOS version upgrade or device transfer. Can I continue using these locally stored localIdentifiers? Or is there another recommended approach, such as using PHCloudIdentifier?
2
0
391
Feb ’25
Crash in Photos framework
Hi This is one of our top crashes. It does not contain any of our code in the stacktrace and we can't reproduce it. Those points make this crash very hard to understand and fix. We know that most of the crashes are happening on iPhone 13 with iOS 18.x.x. Also we see that a lot of cases happen when app goes into background (stacktrace contains -[UIApplication _applicationDidEnterBackground]). 2025-03-04_16-06-00.3670_-0500-6a273c7d5da97f098b5cc24898bb9761dc45208e.crash 2025-03-04_20-21-08.6609_-0500-2c08f640900f8a62c4f8a4f6f2a61feb052e66dd.crash 2025-03-04_20-46-27.7138_+0000-4d7ea89b1b564eda22ca63e708f7ad3909c7b768.crash
2
0
462
Mar ’25
Unable to Fetch Videos from Recently Deleted Album Using Photos Framework in iOS 18.3.1
Hello everyone, I’m working on an iOS app that fetches videos from the "Recently Deleted" album using the Photos framework in Swift. However, I’m unable to fetch any videos, even though the "Recently Deleted" album contains 233 items (including videos), as seen in the Photos app. Environment: iOS Version: 18.3.1 Xcode Version: 16.2 Swift Version: Swift 5 Device: iPhone (simulator and physical device both tested) Photo Library Permission: "All Photos" access granted Recently Deleted Lock: Face ID/Passcode is disabled for "Recently Deleted"
2
0
127
Mar ’25
Images with unusual color spaces not correctly loaded by Core Image
Some users reported that their images are not loading correctly in our app. After a lot of debugging we identified the following: This only happens when the app is build for Mac Catalyst. Not on iOS, iPadOS, or “real” macOS (AppKit). The images in question have unusual color spaces. We observed the issue for uRGB and eciRGB v2. Those images are rendered correctly in Photos and Preview on all platforms. When displaying the image inside of a UIImageView or in a SwiftUI Image, they render correctly. The issue only occurs when loading the image via Core Image. When comparing the different Core Image render graphs between AppKit (working) and Catalyst (faulty) builds, they look identical—except for the result. Mac (AppKit): Catalyst: Something seems to be off when Core Image tries to load an image with foreign color space in Catalyst. We identified a workaround: By using a CGImageDestination to transcode the image using the kCGImageDestinationOptimizeColorForSharing option, Image I/O will convert the image to sRGB (or similar) and Core Image is able to load the image correctly. However, one potentially loses fidelity this way. Or might there be a better workaround?
2
3
158
Aug ’25
Does CMIO support "hide" build-in camera
Hi guys, Can I use CMIO to achieve the following feature on macOS when a USB device (Camera/Mic/Speaker) is connected: When a third-party video conferencing app is not in a meeting, ensure the app defaults to using the USB device (Camera/Mic/Speaker). When a third-party conferencing app is in a meeting, ensure the app automatically switches to the USB device (Camera/Mic/Speaker).
2
0
170
Jul ’25
WorldCaptureKit
Does the library exists in xCode 16.4? "import WorldCaptureKit" gives error "No such module 'WorldCaptureKit'". And I do not find any information about the library in the apple documentation. But AI keeps suggesting me to use the library
2
0
123
Jun ’25
any app shows a black square instead of the camera picture
Hi! I am making an app for Apple Vision pro (VisionOS 2.5) that is scanning the surroundings and recognises all the texts around you. I tried to use the AVCaptureSession library, but when I run the app from xcode on the real AVP device, the camera is not accessible. I enabled the camera access in my Info.plist: NSCameraUsageDescription Used for live text recognition and I checked camera settings in the AVP, there are no restrictions. However I have always a black square with a crossed camera icon displayed instead of the image from the camera. I tried a couple of different apps from Github using the AVCaptureSession and they all display the black square instead of the picture. What can be wrong with the camera?
2
0
130
Jun ’25
Why a driverkit extension needs a CMIO extension
I developed a driverkit extension based on overriding-the-default-usb-video-class-extension, but the link didn’t give the details of realization. I asked DTS who gave two tips: 1, Do you also have a CMIO extension to load in place of the default overriding-the-default-usb-video-class-extension 2, Your DriverKit extension’s info.plist is also missing the CameraAssistantBundleID. I want to know why a driverkit extension needs a CMIO extension, what’s the data and control flow?
2
0
144
Jun ’25
After iOS 18.5, the AVFoundation AVCaptureSessionInterruptionReason.videoDeviceNotAvailableWithMultipleForegroundApps error has caused a significant increase in camera black screen issues.
Issue: After iOS 18.5 release, our app is experiencing a significant increase in AVCaptureSessionInterruptionReason.videoDeviceNotAvailableWithMultipleForegroundApps errors. Details: Our camera-related code has not been updated recently.However, we've observed that the error rate has significantly increased starting from May 2025. The error rate has risen from approximately 0.02% (2 in 10,000 users) to 0.1% (1 in 1,000 users). This represents a 5x increase in error occurrence. The frequency has increased noticeably since iOS 18.5 This is affecting our app's camera functionality and user experience Questions: Are there any known changes in iOS 18.5 regarding camera access management? What are the recommended best practices to handle this interruption reason? Are there any API changes we should be aware of? Best, Shay
2
1
462
Oct ’25