Blackmagic Forum

Any advice please? Unsure of the exact technical term - video scan lines, de-flicker?

I shot some 4k all-Intra 10bit footage on a Lumix GH5 camera; indoors, a little dark, but would appear that the artificial lighting in one setting may has introduced 'scan lines' in the footage. I assume this is to do with the local power (EU, Spain) & I guess this may have been avoided in the shooting itself by using the GH5's synroscan, but the lines were not evident at the time in the viewfinder.

Playing back in a 1080p 25fps timeline: there are horizontal black bars slowly scrolling down the view from top to bottom. Any advice as to how these might be best removed in post?

These are not exactly scan lines, but a phase mismatch of your shutter angle and/or fps with the local grid frequency. Pretty hard to cure in post. You may try the new Deflicker filter in DR15 (but careful if you are using your system professionally, it's an early beta).

Anyway, you'll need a lot of fiddling with the parameters, I recently had a similar case. A cameraman was using a camera he was not familiar with for some important pick-up footage when his main camera lost power. Even with a lot of fiddling, I was never able to get rid of the effect completely.

Others should chime in if they know better software for that, and you may want to change your heading to something like "Remove light source interference?".

http://revisionfx.com/products/deflicker/

This product can work miracles for that type of footage. I think they have an OFX version but I have not used it. I can vouch for the After Effects plug-in though.

Try before you buy, if you go for the OFX version.
Since this should be a temporal process, it can be tricky with third party stuff as an OFX in DR. I have not used that particular product, but Re:VisionFX makes very good software.

Uli Plank wrote:Try before you buy, if you go for the OFX version.
Since this should be a temporal process, it can be tricky with third party stuff as an OFX in DR. I have not used that particular product, but Re:VisionFX makes very good software.

Ta. No Resolve OFX version, but may have a look at the Demos for Adobe Premier & After FX.

PS: Will take a look at Digital Anarchy's Flicker Free: available for OFX, half the price of Revision and with 30 day trial. Review: Product: https://digitalanarchy.com/Flicker/main.html

Why not try DR15 first? This problem (and it's cure) can be very specific to the individual shooting conditions.

Uli Plank wrote:Why not try DR15 first? This problem (and it's cure) can be very specific to the individual shooting conditions.

Update: Indeed, DR15's onboard Deflicker works perfectly to remove the bands, using the 'Fluoro Light' preset. Moving on ...