Horizontal color banding across middle of face?
 

Hi all,

Are the horizontal color lines across the middle of the subject's face (easiest seen from left cheek, across the nose, and through the right cheek) considered color banding? I've checked multiple threads and downloaded other users' attachments, and haven't found something exactly like this although I'm sure I'm missing it among the multitude of threads and posts.

Could someone clarify what this is and if there are specific plugins or filters to help rectify?

I really appreciate it...

I think it has something to do with the picture to the right of the same lines affected - see the high contrast white and black horizontal lines which are supposed to be there? Almost like a type of bleeding that affects those lines, but odd that there's such a big gap and that it doesn't border the part on the line that I'd think it would. Have you tried it on any other playback machines to see if it does the same thing?

I think I can picture what you're referring to regarding the white and black horizontal lines that are supposed to be there... I haven't come across this in any other capture in the past. I have tried watching on multiple playback machines, each present the same thing. Thank you for looking and responding - glad I'm not the only one to find it odd.

Without an AVI sample file to play with, I'd take a guess that maybe Camcorder Color Denoiser (CCD) plugin in Virtualdub could diminish the effects of this.

It's meant to get rid of those rows of color glitches often seen with camcorder recordings, as well as normal VCR recordings like VHS that are prone to color issues like this. Hard to tell from the snapshots if it's just lighter luminance or if it's a different color. If it's a color issue, CCD is designed to help with that.

I think it's included in the Virtualdub 1.9.11 + Filters rar package in this post https://www.digitalfaq.com/forum/vid...lters-pre.html

Or there's a more recent version of that plugin here https://acobw.narod.ru/ if you already have Virtualdub installed.

Try adjusting the threshold value in the filter if default isn't enough.

Thank you for the suggestion, Keaton. I tried CCD, eventually bumping up the threshold to the max but it didn't help. Here is a 3 second sample if you would have any time to take a look. Many thanks for responding with your suggestion and links.

Thanks for the video sample.

I haven't experienced an issue like this, so I don't have any advice.

I looked at the Red, Green and Blue color channels separately with Avisynth ShowRed(), ShowGreen(), ShowBlue() and I see those lines in each one. So it sure looks like a luminance issue.

The filters I've dealt with seem to rely on differences in neighboring frames and neighboring pixels. So when most frames show the same level of luminance in that row, I would not expect a filter could detect a difference and do anything to change it.

Perhaps, in theory, a filter that looks at neighboring luminance levels above and below those rows could average the lighter rows with the darker ones. But I don't know of such a filter. That doesn't mean it doesn't exist. I just haven't experienced one.

The lower 60% of the image seems darker-
just as an idea: Maybe boost the gamma of the lower region,... (finding the right adjustment and position might take a bit of testing)