Baked-in interference

[Sunk]

I've recently purchased a bunch of TV recordings on tape and one of them exhibits this wave-like pattern moving from right to left. I assume it's some kind of interference that the VCR was picking up while recording. While I would normally ignore this sort of thing, this one in particular has a very nasty side effect to it: it messes with the card's proc amp's gain settings, making the video bright the moment one of the waves appears on screen.

Is this manageable with some AviSynth work or is it over and I'd just have to deal with it?

P.S.: Ignore the fact that there's no line TBC and the levels are messed up, this capture was hastily made just to show you the pattern.

[Sharc]

Maybe you could try with DeFreq
http://www.avisynth.nl/users/fizick/defreq/defreq.html

or FanFilter
http://www.avisynth.nl/users/vcmohan/FanFilter/FanFilter.html