Before I start, I'm aware that this problem has been posted a few times before, that there isn't an easy fix and that it's best to reshoot. I have no option of reshooting and am happy to spend a bitter time trying for a solution, however partial. Any comments on my attempts so far would be greatly appreciated!
So the problem is horizontal lines of flicker resulting from a clash between shutter speed and lighting frequency. In this case I tried changing shutter speed but flicker persisted. I didn't try changing the frame rate from 25 to 24 and am not sure if this would've helped.
Here's a sample of footage:
So it first looked to me like undulating lines of darkness and brightness. So I made a gradient mask and key-framed it to the movement of the flicker bands.
Here's the gradient mask:
I then tried using the mask as a luma matte for an adjustment layer. So far I've tried changing the brightness, but it looks to be more than that.
Does anyone have a better idea of the way the bands change the "original" image? And am I completely barking up the wrong tree or wasting my time? I've not had that much experience with grading but have access to Colorista if that helps.