I have tried everything but it looks to be impossible to get MTKView to display full range of colors of HDR CIImage made from CVPixelBuffer (in 10bit YUV format). Only builtin layers such as AVCaptureVideoPreviewLayer, AVPlayerLayer, AVSampleBufferDisplayLayer are able to fully display HDR images on iOS. Is MTKView incapable of displaying full BT2020_HLG color range? Why does MTKView clip colors no matter even if I set pixel Color format to bgra10_xr or bgra10_xr_srgb?  convenience init(frame: CGRect, contentScale:CGFloat) {         self.init(frame: frame)         contentScaleFactor = contentScale     }     convenience init(frame: CGRect) {         let device = MetalCamera.metalDevice         self.init(frame: frame, device: device)         colorPixelFormat = .bgra10_xr         self.preferredFramesPerSecond = 30     }     override init(frame frameRect: CGRect, device: MTLDevice?) {         guard let device = device else {             fatalError("Can't use Metal")         }         guard let cmdQueue = device.makeCommandQueue(maxCommandBufferCount: 5) else {             fatalError("Can't make Command Queue")         }         commandQueue = cmdQueue         context = CIContext(mtlDevice: device, options: [CIContextOption.cacheIntermediates: false])         super.init(frame: frameRect, device: device)         self.framebufferOnly = false         self.clearColor = MTLClearColor(red: 0, green: 0, blue: 0, alpha: 0)     } And then rendering code:  override func draw(_ rect: CGRect) {         guard let image = self.image else {             return         }         let dRect = self.bounds         let drawImage: CIImage         let targetSize = dRect.size         let imageSize = image.extent.size         let scalingFactor = min(targetSize.width/imageSize.width, targetSize.height/imageSize.height)         let scalingTransform = CGAffineTransform(scaleX: scalingFactor, y: scalingFactor)         let translation:CGPoint = CGPoint(x: (targetSize.width - imageSize.width * scalingFactor)/2 , y: (targetSize.height - imageSize.height * scalingFactor)/2)         let translationTransform = CGAffineTransform(translationX: translation.x, y: translation.y)         let scalingTranslationTransform = scalingTransform.concatenating(translationTransform)        drawImage = image.transformed(by: scalingTranslationTransform)         let commandBuffer = commandQueue.makeCommandBufferWithUnretainedReferences()         guard let texture = self.currentDrawable?.texture else {             return         }         var colorSpace:CGColorSpace                 if #available(iOS 14.0, *) {             colorSpace = CGColorSpace(name: CGColorSpace.itur_2100_HLG)!         } else {             // Fallback on earlier versions             colorSpace = drawImage.colorSpace ?? CGColorSpaceCreateDeviceRGB()         }         NSLog("Image \(colorSpace.name), \(image.colorSpace?.name)")         context.render(drawImage, to: texture, commandBuffer: commandBuffer, bounds: dRect, colorSpace: colorSpace)         commandBuffer?.present(self.currentDrawable!, afterMinimumDuration: 1.0/Double(self.preferredFramesPerSecond))         commandBuffer?.commit()     }

I get the following error when configuring MCBrowserViewController to look for nearby peers. And this is despite appending the required info in info.plist namely, [MCNearbyServiceBrowser] NSNetServiceBrowser did not search with error dict [{     NSNetServicesErrorCode = "-72008";     NSNetServicesErrorDomain = 10; }]. NSLocalNetworkUsageDescription <string>Need permission to discover and connect to My Service running on peer iOS device</string> NSBonjourServices <array> <string>_my-server._tcp</string> <string>_my-server._udp</string> </array> Here is my code: let browser = MCBrowserViewController(serviceType: "my-server", session: session)             browser.delegate = self             browser.minimumNumberOfPeers = kMCSessionMinimumNumberOfPeers             browser.maximumNumberOfPeers = 1             self.present(browser, animated: true, completion: nil)

The AppStore version of my app works perfectly fine. But the moment I build the same code with XCode 13, AVAssetWriter fails with errors at the very beginning itself both on iOS 14 and iOS 15. This happens with Multicam session only. Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSLocalizedFailureReason=An unknown error occurred (-12780) I am wondering what could be wrong. I even passed default settings to AVAssetWriter (the recommended ones). Update: It turned out to be an issue with audio settings.

In the WWDC 2021 video 10047, it was mentioned to look for availability of Lossless CVPixelBuffer format and fallback to normal BGRA32 format if it is not available. But in the updated AVMultiCamPiP sample code, it first looks for Lossy format than the lossless. Why is it so and whats the exact difference it would make if we select lossy vs lossless?

WWDC 2021 session 10047 recommends to observe changes in AVCaptureDevice.isCenterStageEnabled which is a class property. But how exactly do we observe a class property in Swift?

For editing ProRes videos, what are the right compression settings for AVAssetWriter? This is for editing an existing ProRes video.

@AVFoundationEngineers I am trying to observe isCenterStageEnabled property as follows: AVCaptureDevice.self.addObserver(self, forKeyPath: "isCenterStageEnabled", options: [.initial, .new], context: &CapturePipeline.centerStageContext) I have set the centerStageControlMode to .cooperative. The KVO fires only when I do make changes to property AVCaptureDevice.isCenterStageEnabled in my code. KVO is NOT fired when the user toggles the centerStage property from Control Center. Is this a bug?

Hourly sales data is not updated in appstoreconnect for the past 3 days. Two days ago, the same website running on different devices were showing different hourly sales figures and now they all show zero sales. Is it a problem on client side or a server outage?

I am trying to use a CIColorKernel or CIBlendKernel with sampler arguments but the program crashes. Here is my shader code which compiles successfully. extern "C" float4 wipeLinear(coreimage::sampler t1, coreimage::sampler t2, float time) { float2 coord1 = t1.coord(); float2 coord2 = t2.coord(); float4 innerRect = t2.extent(); float minX = innerRect.x + time*innerRect.z; float minY = innerRect.y + time*innerRect.w; float cropWidth = (1 - time) * innerRect.w; float cropHeight = (1 - time) * innerRect.z; float4 s1 = t1.sample(coord1); float4 s2 = t2.sample(coord2); if ( coord1.x > minX && coord1.x < minX + cropWidth && coord1.y > minY && coord1.y <= minY + cropHeight) { return s1; } else { return s2; } } And it crashes on initialization. class CIWipeRenderer: CIFilter { var backgroundImage:CIImage? var foregroundImage:CIImage? var inputTime: Float = 0.0 static var kernel:CIColorKernel = { () -> CIColorKernel in let url = Bundle.main.url(forResource: "AppCIKernels", withExtension: "ci.metallib")! let data = try! Data(contentsOf: url) return try! CIColorKernel(functionName: "wipeLinear", fromMetalLibraryData: data) //Crashes here!!!! }() override var outputImage: CIImage? { guard let backgroundImage = backgroundImage else { return nil } guard let foregroundImage = foregroundImage else { return nil } return CIWipeRenderer.kernel.apply(extent: backgroundImage.extent, arguments: [backgroundImage, foregroundImage, inputTime]) } } It crashes in the try line with the following error: Fatal error: 'try!' expression unexpectedly raised an error: Foundation._GenericObjCError.nilError If I replace the kernel code with the following, it works like a charm: extern "C" float4 wipeLinear(coreimage::sample_t s1, coreimage::sample_t s2, float time) { return mix(s1, s2, time); }

I have a .cube file storing LUT data, such as this: TITLE "Cool LUT" LUT_3D_SIZE 64 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0157 0.0000 0.0000 0.0353 0.0000 0.0000 My question is how do I load required NSData that can be used in CIColorCube filter? When using Metal, I convert this data into MTLTexture using AdobeLUTParser. Not sure what to do in case of CoreImage.

I am trying to develop tone curves filter using Metal or Core Image as I find CIToneCurve filter is having limitations (number of points are atmost 5, spline curve it is using is not documented, and sometimes output is a black image even with 4 points). Moreover it's not straightforward to have separate R,G,B curves independently. I decided to explore other libraries that implement tone curve and the only one that I know is GPUImage (few others borrow code from the same library). But the source code is too cryptic to understand and I have [doubts] about the manner in which it is generating look up texture (https://stackoverflow.com/questions/70516363/gpuimage-tone-curve-rgbcomposite-filter). Can someone explain how to correctly implement R,G,B, and RGB composite curves filter like in Mac Photos App?

Is it possible to pass MTLTexture to Metal Core Image Kernel? How can Metal resources be shared with Core Image?

@AVFoundationEngineers I browsed through AVCustomEdit sample code and notice the following: - (void)startVideoCompositionRequest:(AVAsynchronousVideoCompositionRequest *)request { @autoreleasepool { dispatch_async(_renderingQueue,^() { // Check if all pending requests have been cancelled if (_shouldCancelAllRequests) { [request finishCancelledRequest]; } else { NSError *err = nil; // Get the next rendererd pixel buffer CVPixelBufferRef resultPixels = [self newRenderedPixelBufferForRequest:request error:&err]; if (resultPixels) { // The resulting pixelbuffer from OpenGL renderer is passed along to the request [request finishWithComposedVideoFrame:resultPixels]; CFRelease(resultPixels); } else { [request finishWithError:err]; } } } } The startVideoComposition request returns early without calling finishWithComposedVideoFrame as the processing takes place asynchronously in a dispatchQueue. However, the documentation of startVideoCompositionRequest states the following: Note that if the custom compositor's implementation of -startVideoCompositionRequest: returns without finishing the composition immediately, it may be invoked again with another composition request before the prior request is finished; therefore in such cases the custom compositor should be prepared to manage multiple composition requests. But I don't see anything in the code that is prepared to handle multiple composition requests of same video frame. How is one supposed to handle this case?

@AVFoundation Engineers, I get this bug repeatedly when using AVComposition & AVVideoComposition. Sometimes AVPlayer seek to time completion handler is not called. I check for a flag whether seek is in progress before placing another seek request. But if the completion handler is never invoked, all further seeks stall as flag remains true. What is a reliable way to know seek is not in progress before initiating another seek request. playerSeeking = true         player.seek(to: time, toleranceBefore: .zero, toleranceAfter: .zero) { [weak self] completed             if !completed {                 NSLog("Seek not completed \(time.seconds)")             }             guard let self = self else {                 return             }             self.playerSeeking = false             if self.player.rate == 0.0 {                 self.updateButtonStates()             }         }

I wrote the following Metal Core Image Kernel to produce constant red color. extern "C" float4 redKernel(coreimage::sampler inputImage, coreimage::destination dest) {     return float4(1.0, 0.0, 0.0, 1.0); } And then I have this in Swift code: class CIMetalRedColorKernel: CIFilter {     var inputImage:CIImage?     static var kernel:CIKernel = { () -> CIKernel in         let bundle = Bundle.main         let url = bundle.url(forResource: "Kernels", withExtension: "ci.metallib")!         let data = try! Data(contentsOf: url)         return try! CIKernel(functionName: "redKernel", fromMetalLibraryData: data)     }()     override var outputImage: CIImage? {         guard let inputImage = inputImage else {             return nil         }         let dod = inputImage.extent         return CIMetalTestRenderer.kernel.apply(extent: dod, roiCallback: { index, rect in             return rect         }, arguments: [inputImage])     } } As you can see, the dod is given to be the extent of the input image. But when I run the filter, I get a whole red image beyond the extent of the input image (DOD), why? I have multiple filters chained together and the overall size is 1920x1080. Isn't the red filter supposed to run only for DOD rectangle passed in it and produce clear pixels for anything outside the DOD?