I found that it seems that set presentsWithTransaction to true can solve this problem..... But this needs that rendering thread (or present drawable thread must be main thread.)

Here is the crash stack trace Application Specific Information: *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread.' Last Exception Backtrace: 0 CoreFoundation 0x000000018c8fde48 0x000000018c8f4000 + 40520 1 libobjc.A.dylib 0x0000000185bc78d8 0x0000000185bb0000 + 96472 2 CoreAutoLayout 0x00000001a9304e84 0x00000001a92f7000 + 56964 3 CoreAutoLayout 0x00000001a92fb9b4 0x00000001a92f7000 + 18868 4 CoreAutoLayout 0x00000001a92fb8e4 0x00000001a92f7000 + 18660 5 CoreAutoLayout 0x00000001a92fb670 0x00000001a92f7000 + 18032 6 UIKitCore 0x000000018eacf284 0x000000018eac9000 + 25220 7 UIKitCore 0x000000018eacd860 0x000000018eac9000 + 18528 8 QuartzCore 0x000000018dfa0b0c 0x000000018df97000 + 39692 9 QuartzCore 0x000000018dfb41c0 0x000000018df97000 + 119232 10 QuartzCore 0x000000018dfc5534 0x000000018df97000 + 189748 11 QuartzCore 0x000000018dffa930 0x000000018df97000 + 407856 12 QuartzCore 0x000000018dfe3bb4 0x000000018df97000 + 314292 13 CoreFoundation 0x000000018c985d40 0x000000018c8f4000 + 597312 14 CoreFoundation 0x000000018c90e290 0x000000018c8f4000 + 107152 15 CoreFoundation 0x000000018c96fc60 0x000000018c8f4000 + 506976 16 CoreFoundation 0x000000018c974ec0 0x000000018c8f4000 + 528064 17 Flutter 0x000000010be19acc 0x000000010bb2c000 + 3070668 18 Flutter 0x000000010be195c8 0x000000010bb2c000 + 3069384 19 libsystem_pthread.dylib 0x00000001da9866cc 0x00000001da985000 + 5836 20 libsystem_pthread.dylib 0x00000001da985ba4 0x00000001da985000 + 2980 Binary Images: 0x000000010bb2c000 - 0x000000010c30bfff Flutter arm64 <4c4c448455553144a17746f7af31d4ec> /private/var/containers/Bundle/Application/B2924516-9912-465A-A74E-74DB5A6026F7/Runner.app/Frameworks/Flutter.framework/Flutter 0x0000000185bb0000 - 0x0000000185bf3e1f libobjc.A.dylib arm64-unknown <d6ecfb730ca23a21a3a919e450d3b49c> /usr/lib/libobjc.A.dylib 0x000000018c8f4000 - 0x000000018ccd9fff CoreFoundation arm64-unknown <725e49f4653b39bf9a7a8a3250911ecb> /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation 0x000000018df97000 - 0x000000018e2f5fff QuartzCore arm64-unknown <e0e47b5d2805361d88c4875002b0244d> /System/Library/Frameworks/QuartzCore.framework/QuartzCore 0x000000018eac9000 - 0x00000001902b4fff UIKitCore arm64-unknown <59cbc9b530ae396ea269a986640001bc> /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore 0x00000001a92f7000 - 0x00000001a933ffff CoreAutoLayout arm64-unknown <e96465db77983db5bc5851e367946a04> /System/Library/PrivateFrameworks/CoreAutoLayout.framework/CoreAutoLayout 0x00000001da985000 - 0x00000001da990fff libsystem_pthread.dylib arm64-unknown <f2ba7ec0f75a3345b4f6f7da4979b902> /usr/lib/system/libsystem_pthread.dylib

Hi, Here is the code I use to measure: class TestVC: UIViewController { let metalLayer:CAMetalLayer = CAMetalLayer() var displayLink:CADisplayLink! var thread:Thread! override func viewDidLoad() { super.viewDidLoad() self.view.backgroundColor = .red let scale = UIScreen.main.scale metalLayer.frame = self.view.bounds metalLayer.drawableSize = CGSize(width: self.view.frame.width * scale, height: self.view.frame.height * scale) self.view.layer.addSublayer(metalLayer) self.addDisplayLinkInTask() } func addDisplayLinkInTask() { self.thread = Thread(block: { RunLoop.current.add(NSMachPort(), forMode: .common) RunLoop.current.run() }) self.thread.name = "sub thread" self.thread.start() self.perform(#selector(addDisplayLink), on: thread, with: nil, waitUntilDone: false) } @objc func addDisplayLink() { self.displayLink = CADisplayLink(target: self, selector: #selector(onDisplayLink)) if #available(iOS 15.0, *) { self.displayLink.preferredFrameRateRange = .init(minimum: 60, maximum: 120, preferred: 120) } else { self.displayLink.preferredFramesPerSecond = 120 } self.displayLink.add(to: .current, forMode: .common) } @objc private func onDisplayLink() { let startTime = CACurrentMediaTime() let frameDrawable = metalLayer.nextDrawable()! let timeUsed = CACurrentMediaTime() - startTime // If time used to get next drawble over 3ms, // we print it here to indicate this method take much time! if (timeUsed > 0.003) { print("CAMetalLayer.nextDrawable take much time!! -> \(String(format: "%.2f", timeUsed * 1000)) ms") } frameDrawable.present() } }

I come cross this also with 255.255.255.255 boardcast.... Any way to solve?

Hi, I have add the video link in post😄

It will change by settings -> screentime -> content & privacy -> Allowed Apps,turn off the camera item

It will change by settings -> screentime -> content & privacy -> Allowed Apps,turn off the camera item

let tapInit: MTAudioProcessingTapInitCallback = {       (tap, clientInfo, tapStorageOut) in       tapStorageOut.pointee = clientInfo     }  var callback = MTAudioProcessingTapCallbacks(version: kMTAudioProcessingTapCallbacksVersion_0, clientInfo:UnsafeMutableRawPointer(Unmanaged.passUnretained(self.engine).toOpaque()), init: tapInit, finalize: tapFinalize, prepare: tapPrepare, unprepare: tapUnprepare) { tap, numberFrames, flags, bufferListInOut, numberFramesOut, flagsOut in               guard MTAudioProcessingTapGetSourceAudio(tap, numberFrames, bufferListInOut, flagsOut, nil, numberFramesOut) == noErr else {         preconditionFailure()       }       let storage = MTAudioProcessingTapGetStorage(tap)       let engine = Unmanaged<Engine>.fromOpaque(storage).takeUnretainedValue()       engine.render(bufferPtr: bufferListInOut)            }

But I can't find any Machine Learning framework in iOS SDK... In Core ML I can't find any API called MLCDevice 😶😶

Ok,thx

MCLDevice ane() ？？ @robnotyou. I don't find this API