Hello, I’ve started testing the Metal Shader Converter to convert my HLSL shaders to metallib directly, and I was wondering if the option ’-frecord-sources’ was supported in any way? Usually I’m compiling my shaders as follows (from Metal): xcrun -sdk macosx metal -c -frecord-sources shaders/shaders.metal -o shaders/shaders.air xcrun -sdk macosx metallib shaders/shaders.air -o shaders/shaders.metallib The -frecord-sources allow me to see the source when debugging and profiling a Metal frame. Now with DXC we have a similar option, I can compile a typical HLSL shader with embedded debug symbols with: dxc -T vs_6_0 -E VSMain shaders/triangle.hlsl -Fo shaders/triangle.dxil -Zi -O0 -Qembed_debug The important options here are ’-Zi` and ’-Qembed_debug’, as they make sure debug symbols are embedded in the DXIL. It seems that right now Metal Shader Converter doesn’t pass through the DXIL debug information, and I was wondering if it was possible. I’ve looked at all the options in the utility and haven’t seen anything that looked like it. Right now debug symbols in my shaders is a must-have, so I’ll explore other routes to convert my HLSL shaders to Metal (I’ve been testing spir-v cross to do the conversion, I haven’t actually tested the debug symbols yet, I’ll report back later). Thank you for your time!

We are using AVAssetWriter to write videos using both HEVC and H.264 encoding. Occasionally, we get reports of choppy footage in which frames appear out of order when played back on a Mac (QuickTime) or iOS device (stock Photos app). This occurs extremely unpredictably, often not starting until 20+ minutes of filming, but occasionally happening as soon as filming starts. Interestingly, users have reported the issue goes away while editing or viewing on a different platform (e.g. Linux) or in the built-in Google Drive player, but comes back as soon as the video is exported or downloaded again. When this occurs in an HEVC file, converting to H.264 seems to resolve it. I haven't found a similar fix for H.264 files. I suspect an AVAssetWriter encoding issue but haven't been able to uncover the source. Running a stream analyzer on HEVC files with this issue reveals the following error: Short-term reference picture with POC = [some number] seems to have been removed or not correctly decoded. However, running a stream analyzer on H.264 files with the same playback issue seems to show nothing wrong. At a high level, our video pipeline looks something like this: Grab a sample buffer in captureOutput(_ captureOutput: AVCaptureOutput!, didOutputVideoSampleBuffer sampleBuffer: CMSampleBuffer!) Perform some Metal rendering on that buffer Pass the resulting CVPixelBuffer to the AVAssetWriterInputPixelBufferAdaptor associated with our AVAssetWriter Example files can be found here: https://drive.google.com/drive/folders/1OjDZ3XaC-ubD5hyDiNvMQGl2NVqZbWnR?usp=sharing This includes a video file suffering this issue, the same file fixed after converting to mp4, and a screen recording of the distorted playback in QuickTime. Can anyone help point me in the right direction to solving this issue? I can provide more details as necessary.

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); }