This may be a particularly specialized application, but it sure works well. I shoot a lot in Europe. The 50-Hz AC system frequently means that night shots with my VX2000 NTSC system will exhibit pronounced flicker as the shutter catches outdoor lighting at the wrong part of the AC sine-wave. I was pretty much reconciled to living with it, until I stumbled across a Donald Graft's anti-flicker plug-in for Virtual Dub called "Deflicker." It's a little tricky to use (you have to turn off the output window in Virtual Dub or it won't work -- this isn't documented anywhere in the instructions). However, the results are amazing. The flicker is completely gone and there is, at least to my eye, no degradation of the image whatsoever. I ran it on a short video I shot of Venice at night, and then put together a clip with the Deflicker-processed video side-by-side with the unprocessed video. This is exactly the tool that I needed.

As I said, it's a pretty specialized application, but for anyone shooting NTSC in a 50-Hz AC location, it does the trick quite handily.

Thank you for posting this. I have been looking pretty hard for a de-flicker filter. Although Im not completely sure it will work with my problem (many stills with brightness flicker in time lapse, will probably need to be prerendered into video).
Thanks for bringing this to light. The only other brightness deflicker filter is part of a bundle that costs $599!

Can you point me to where I can download this? I found one download but it only had a .dll and nothing happenned when I put it in my plugin floder. thanks.