It looks like you have to compile ffmpeg with the additional option --enable-cuda-sdk on the configure command line to get the F_scale_cuda and F_yadif_cuda and that could be what gg did. I need to know for sure from him so I can remove them from the manual or annotate it better. He is working on one of the 16 thirdparty library updates for the last 10 days and so is trying to really concentrate on that. But when he finishes, I have a lot of questions for him.