In the WWDC Explore Computer Vision APIs presentation it was said (at 23:30) that "we will make the Core Image Kernel for the optical flow available in the slide attachments". Does anyone know where to find it?

I have an app where I am recording a cropped video (full height, cropped width) at 240 fps. It has been working fine for many years on a wide range of hardware. But when I test on my new iPhone 12 Pro it isn't able to keep up and I am seeing about 10 % dropped frames. In my type of application it is pretty obvious to the user that it is not 100 % OK. It is strange that an iPhone 12 can't run a piece of code that an iPhone 6s handles perfectly (as well as a 7+, an 11Pro and a couple of iPads). I am using an AVCaptureSession and an AVAssetWriter. I am using "recommendedVideoSettingsForAssetWriterWithOutputFileType: AVFileTypeQuickTimeMovie" for the asset writer so there shouldn't be any strange format involved. Is there anything new in the iPhone 12 camera that might cause this? Or have I just gotten a bad copy?