Restoring badly digitized VHS

[Graven]

... I suspect somewhere ffmpeg does some interpolation, so upscaling before Stab and downscaling afterwards ...

Thanks for taking so much time to look at this!  I will definitely try out the temporalfix filter as well.

To be clear, my workflow was:

1. ffmpeg - separatefields
2. hybrid - stab()
3. ffmpeg - weave

So, I'm still a little puzzled about the difference between the ffmpeg/hybrid approach vs pure hybrid/vs.