sky distortion (banding)

[annau3120573]

hi there,

I've got this super annoying problem with all my sky clips - (screenshot bellow) 

I've tried everything from changing my sequence setting and my export settings too 

any ideas where I'm going wrong ?

thanks a lot

[title edited by mod for clarity]

[R Neil Haugen]

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

[annau3120573]

Hi Neil 

thanks for such a quick reply - that was my biggest fear actually that it was setting in camera 

it was shot on canon c200 I think ?? I didn't film it 

so there's not much I can do in post ? 

thanks

[Phillip Harvey]

You could try adding some noise into the image to hopefully break it up? I know that's a trick when creating gradients in post. Admittedly I don't know how well it will do if that's burned into camera like that.

[R Neil Haugen]

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

[annau3120573]

thank you so much - I've looked at replacing the sky but i have just too many shots of this- so i'm thinking just to replace the shots  wherever i can . I've read about adding noise and changing to 32bit in After Effects but that didnt help either...this is such a blow as the rest of the music video looks great and now it's all ruined 

thanks for your help tho -  

[R Neil Haugen]

Life is always a Learning Situation, right?

Yea. My first video project, I was very experienced as a stills pro. Setup, camera angle, lighting/contrast exposure spot on. I didn't record separate audio, just a small shotgun mounted on the cam.

Might as well as left the video gear in the bag. Sheesh. Who knew sound was even more important than the image?

Neil

[annau3120573]

oh i hear that

I do both videos and stills and I feel like every project is a massive lesson- do people ever feel professional enough ? i've been doing this for years and I still feel like I don't know very much 😄

[R Neil Haugen]

Hey, I know the whole thing of questioning how much do *I* really know ... ! Well, I know enough about the parts of any of these apps that I have to use all the time, and pretty good about parts I use often, but less about the parts I don't use so much if at all. There's no way that's not going to lead to feeling like one's knowledge is somehow incomplete.

Neil

[Peru Bob]

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

[salvo34]

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

=======

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 ? "

[annau3120573]

so we actually managed to get rid of it- not completely but it's much better around  the level of -  'what sky?'

I will definitely post the link when it comes out 

thanks for the words of support