In your kernel, colors are usually normalized to [0.0 ... 1.0], based on the underlying color space. So even if values are stored in 10-bit inters in a texture, your shader will get them as normalized floats. I emphasized the color space above because it is used when translating the colors from the source into those normalized values. When you are using the default sRGB color space, the wide gamut from the HDR source doesn't fit into the sRGB [0.0 ... 1.0] spectrum. That's why you may get values outside that range in your kernel. This is actually useful in most cases because most filter operations that are designed for sRGB still work then. The color invert example above, however, is not. You have two options here that I know of: You can change the workingColorSpace of the CIContext you are using to the HDR color space of the input: let ciContext = CIContext(options: [.workingColorSpace: CGColorSpace(name: CGColorSpace.itur_2020)!]) Then all color values should be capped to [0.0 ... 1.0] in your kernel, where 0.0 is the darkest HDR color value and 1.0 is the brightest. You can safely perform the inversion with 1.0 - x then. However, keep in mind that some other filters will then not produce the correct result because they assume the input to be in (linear) sRGB—Core Image's default. The second option is that you convert ("color match") the input into the correct color space before passing it into your kernel and back to working space again before returning: return kernelOutput.matchedToWorkingSpace(from: colorSpace)

@IanOllmann There seems to be a bug in the AppleEXR encoder, causing a BAD_ACCESS when encoding images with height 16. Could you please have a look? (FB9080694) Thanks!

I'm not sure if you are able to access sub-images using NSImage. However, you should be able to do so with a CGImageSource: let source = CGImageSourceCreateWithURL(newURL, nil) let numSubImages = CGImageSourceGetCount(source) for i in 0..<numSubImages { &#9;&#9;let subImage = CGImageSourceCreateImageAtIndex(source, i, nil) &#9;&#9;// subImage is a CGImage, you can convert it to an NSImage if you prefer: &#9;&#9;let nsImage = NSImage(cgImage: subImage, size: NSZeroSize) &#9;&#9;// handle image... }

Have you tried setting the magnificationFilter of the view's layer to nearest?

Do built-in filters like CIGaussianBlur still work?

I encountered a very similar bug and I found a workaround. Can you try context.heifRepresentation(of: image.settingAlphaOne(in: image.extent), …) and see if that works?

Found it: I'm getting the attachments (metadata) of the incoming sample buffers and accidentally leaked the dictionary due to wrong bridging. So instead of this NSDictionary* attachments = (_bridge NSDictionary* Nullable)CMCopyDictionaryOfAttachments(NULL, sampleBuffer, kCMAttachmentModeShouldPropagate); I should have done this NSDictionary* attachments = (bridgetransfer NSDictionary* Nullable)CMCopyDictionaryOfAttachments(NULL, sampleBuffer, kCMAttachmentModeShouldPropagate); Interestingly, this leak caused the capture session to stop delivering new sample buffers after 126 frames—without any warning, error, or notification.