sky distortion (banding)

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this is such a blow as the rest of the music video looks great and now it's all ruined

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sometimes people who make stuff are their harshest critics. Many times authors, for example, will re-write portions of a successful publication, thinking they have to make it better.

At any rate... do your edit with sky you got and then show it to a friend or neighbor or someone...a music video usually isn't long so it's easy to get someone to watch it and listen.

Don't say anything to them before they watch it.

When done, give them a second and then ask, " what do you think of the sky ? "

they will probably reply, " what sky ? "

Can you get away with calling it a "special effect"?

Banding happens when the transition levels between typically low-change areas like a sky or a wall get dumped by the compression algorithms. Compression often takes say 4x4 blocks, and looks to see if they can make them all the same without "visual" damage to the file.

So some blocks may get slightlly moved one way on a channel or two, while the next gets slightlly moved the other direction. If you get several of theses down a tonal/hue transition area, then ... you see banding.

Getting rid of banding is very very difficult. And if you see it on clips coming into PrPro, before you've done any tonal/color changes, that indicates its really a big problem. I'm pretty versed in PrPro's Lumetri panel, the Red Giant Colorista plugins, and to a certain level working color in Resolve. I teach pro colorists how to work in Lumetri, among other things.

And I would find that file difficult to work with. There are times that adding "dither" or colored grain/noise to a file can help minimize banding. If in looking at the scopes of the image, either RGB Parade or Waveform, you can see that there are chunks missing primarily in one channel, there are times things one can do with a channel mixer ... though PrPro's is darn hard to use for this.

I know some colorists who would simply suggest masking/replacing the sky on something like this if you must use the shot. Yea, it can be that much of a problem. Yea, skies and light-colored walls can be a pretty daunting challenge at times.

Neil

That is "banding". Rather common with 8-bit video clips especially. And also, especially a problem with 8-bit long-GOP formats, the highly compressed H.264/H.265 stuff.

Basically, you don't have enough data there to maintain enough levels for a smooth gradient. And there's not really a 'fix' other than shooting with more exactly correct exposure in the camera and if possible, shooting 10 bit.

So ... which camera are you using? What format/codec are you using? What about your in-cam setttings for contrast/saturation?

Neil