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Removing strong flicker from a video

PostPosted: Tue Dec 22, 2020 1:33 pm
by dantastic
Hello, I recently captured some really nice footage, but there were a bunch of photographers there using flash, and it's created really strong (and random) horizontal banding in a lot of the footage.

I've tried the de-flicker tool in resolve, but it only seems to reduce the issue slightly, I also tried Neat video local deflicker, but that also doesn't work.
Image
Is my only option going frame by frame trying to draw rectangles to balance the exposure and using key frames to keep each correction to 1 frame? Any help would be much appreciated:)

Re: Removing strong flicker from a video -

PostPosted: Wed Dec 23, 2020 3:52 pm
by Jim Simon
That's an unavoidable consequence of Rolling Shutter. I also found it extremely annoying and wanted to throttle camera makers for switching from CCD to CMOS.

In the end, I found it best to just accept it and move on.

Re: Removing strong flicker from a video -

PostPosted: Wed Dec 23, 2020 6:58 pm
by wfolta
If there are a limited number of flashes, you can cut them out and use Smooth Cut (available in free version too) to cover over them. He shows some tips to make a two-frame Smooth Cut the default transition so you can apply it in one keystroke. But you basically have to locate the flash, back up two frames and cut, go beyond the end two frames, cut, delete the flash and apply a two-frame Smooth Cut.

So if you have hundreds this might become a bit hard, and if there's fast motion or other motion that Optical Flow can't handle, this might leave a different kind of artifact. Though, I'm thinking a bit of morphish appearance is probably better than ruined frames. And to be honest, you probably can't do anything to a single frame to fix the flash as the flash-affectred pixels are probably WAY overexposed and not recoverable.



I can imagine a very fancy Fusion approach with Optical Flow and an analysis node looking for flashes, but...