VNContoursObservation is taking 715 times as long as OpenCV’s findContours() when creating directly comparable results. VNContoursObservation creates comparable results when I have set the maximumImageDimension property to 1024. If I set it lower, it runs a bit faster, but creates lower quality contours and still takes over 100 times as long. I have a hard time believing Apple doesn’t know what they are doing, so does anyone have an idea what is going on and how to get it to run much faster? There doesn’t seem to be many options, but nothing I’ve tried closes the gap. Setting the detectsDarkOnLight property to true makes it run even slower. OpenCV findContours runs with a binary image, but I am passing a RGB image to Vision assuming it would convert it to an appropriate format. OpenCV: double taskStart = CFAbsoluteTimeGetCurrent(); int contoursApproximation = CV_CHAIN_APPROX_NONE; int contourRetrievalMode = CV_RETR_LIST; findContours(input, contours, hierarchy, contourRetrievalMode, contoursApproximation, cv::Point(0,0)); NSLog(@"###### opencv findContours: %f", CFAbsoluteTimeGetCurrent() - taskStart); ###### opencv findContours: 0.017616 seconds Vision: let taskStart = CFAbsoluteTimeGetCurrent() let contourRequest = VNDetectContoursRequest.init() contourRequest.revision = VNDetectContourRequestRevision1 contourRequest.contrastAdjustment = 1.0 contourRequest.detectsDarkOnLight = false contourRequest.maximumImageDimension = 1024 let requestHandler = VNImageRequestHandler.init(cgImage: sourceImage.cgImage!, options: [:]) try! requestHandler.perform([contourRequest]) let contoursObservation = contourRequest.results?.first as! VNContoursObservation print(" ###### contoursObservation: \(CFAbsoluteTimeGetCurrent() - taskStart)") ###### contoursObservation: 12.605962038040161 The image I am providing OpenCV is 2048 pixels and the image I am providing Vision is 1024.

Hello, I have my largely iOS app running using Mac Catalyst, but I need to limit what Macs will be able to install it from the Mac App Store based on the GPU Family like MTLGPUFamily.mac2. Is that possible? Or I could limit it to Apple Silicon using the Designed for iPad target, but I would prefer to use Mac Catalyst instead of Designed for iPad. Is it possible to limit Mac Catalyst installs to Apple Silicon Macs? Side question: what capabilities are supported by MTLGPUFamily.mac2? I can't find it. My main interest is in CoreML inference acceleration. Thank you.

When I run the performance test on a CoreML model, it shows predictions are 834% faster running on the Neural Engine as it is on the GPU. It also shows, that 100% of the model can run on the Neural Engine: GPU only: But when I set the compute units to all: let config = MLModelConfiguration() config.computeUnits = .all and profile, it shows that the neural engine isn’t used at all. Well, other than loading the model which takes 25 seconds when allowed to use the neural engine versus less than a second when not allowing the neural engine: The difference in speed is the difference between the app being too slow to even release versus quite reasonable performance. I have a lot of work invested in this, so I am really hoping that I can get it to run on the Neural Engine. Why isn't it actually running on the Neural Engine when it shows that it is supported and I have the compute unit set to run on the Neural Engine?

My app is capable of writing multi-gigabyte images. I need a way to allow the user to do something with the full-resolution images (such as AirDrop). It does not appear possible to write the image to Photos since there may not be enough memory to read the whole image in RAM and as far as I can tell PhotoKit allows readonly access. With UIActivityViewController I am able to copy the large images with a NSFileCoordinator, but only if I use an extension of .zip or .bin for the destination URL. The file is copied, but macOS thinks they are archives and not an image. After the file has been copied, changing the extension to .jpg on the Mac allows the copied image to be used, but that is less than an ideal user experience. Zipping the image (that is already compressed) is not a viable solution since the whole image would need to be read to zip it, which may exceed the amount of memory available. Not to mention it is a total waste of time/power consumption. How can I allow a user to copy multi-gigabyte images from my app, and ideally with UIActivityViewController? Here is the code that allows the image to be copied. If I don't use .zip or .bin for the destination URL, the image isn't copied, nothing happens, no errors reported. func copyImage() { let fm = FileManager.default var archiveUrl: URL? var error: NSError? let imageProductURL = TDTDeviceUtilites.getDocumentUrl( forFileName: "hugeImage.jpg") let coordinator = NSFileCoordinator() coordinator.coordinate(readingItemAt: imageProductURL, options: [.forUploading], error: &error) { (zipUrl) in let tmpUrl = try! fm.url( for: .itemReplacementDirectory, in: .userDomainMask, appropriateFor: zipUrl, create: true ).appendingPathComponent("hugeImage.jpg.zip") try! fm.moveItem(at: zipUrl, to: tmpUrl) archiveUrl = tmpUrl } if let url = archiveUrl { let avc = UIActivityViewController(activityItems: [url], applicationActivities: nil) present(avc, animated: true) } else { print(error) } }

I'm experiencing 100% reproducible bug with Xcode. It took me days to figure it out. After many tears shed. Xcode is producing a corrupt binary. It seems like my metal buffers are being mis-aligned or something. The problem showed up after changing the Deployment to iOS 15. It had been at iOS 13 and built and ran without any related issues - for years that I've been developing this app. So at some point after changing the target to iOS 15, compiling the shaders went from about 0.001 seconds to 30 seconds. When that happens, the GPU will also hang with the messages: GPUDebug] Invalid device load executing kernel function "computeArtPointsToRender" encoder: "0", dispatch: 0, at offset 22080048 Shaders.metal:1290:41 - computeArtPointsToRender() To fix the issue, I have to change the build target to iOS 13, clean, build, change to iOS 15, clean, build and then works again as expected (until it doesn't at some random point or until I have restarted the machine). This is 100% reproducible: Restart mac Build project Issue occurs Change build target to iOS 13 Clean build folder Build Change build target to iOS 15 Delete derived files Build Works as expected Xcode: Version 13.1 (13A1030d) macOS: 11.5.2 (20G95) Mac mini (M1, 2020) In my 11+ years as a full time iOS developer, I've never encountered such a serious issue with Xcode. If I don't have stable tools, it is impossible for me to develop.