My most recently uploaded video uses heavy video feedback (two different fb sessions, blended with soft-keying using a third, generated video stream) in FFMPEG, so I used the photosensitivity filter to tame the oscillations so the foreground stands out better. I should post the video itself in the gallery section.
Anyway, this filter works very well. I upscaled to HD before applying it, to exploit the higher resolution, but this increased the processing cost enormously. I’ve compared the SD and HD versions, and I’m uncertain the extra processing cost was justified, but as I like upscaling to HD for publishing, it’s not a big deal for me. Increasing the frame rate might be even better, but I expect that’ll double the processing cost. That’ll make it an overnight job! Not a problem for me, as I’m scripting all the post-processing. So I can run different versions as many times as I like. That’s a big part of why I use FFMPEG. I’m a programmer, so that’s easy for me. YMMV but a decent video editor should have a similar filter and may even offer scripting. I know there’s at least one editor that has that feature, but its expensive.
My point is that you can do this in post-processing. Whether you do it in post, and how you do it, is up to you. I agree with all the advise given here already - I’m just adding my recent experience with some free software.