How to handle heavy noise on red channel?

Hello!

I have a clip with a performer wearing a red santa suite.
The shot is oversaturated and there is lot of noise on the red channel.
Tried with slight desaturation, temporal denoiser, deflicker... But not great result.
The only way to fix I found so far is to track the cloth, completely desaturate it then apply an uniform red.
Before starting with this time consuming task, I wonder if there is some other approach I can try.

Thanks!
Umberto

Hi,
you can use hue vs sat or sat vs sat...or you can split the channel RGB on node and use the denoiser or other tools.


Fabio Bovenzi
Mac Pro 12 Core
Dual D500 Gpu
Blackmagic ULTRASTUDIO 4K
HighSierra 10.13.3
DaVinci Resolve Studio 14.3

Three possible ideas:

1) use a hue vs. sat curve to pull down the red a bit to unclip it a bit

2) there is a method described in one of Alexis Van Hurkman's books where you tweak the RGB Mixer controls to basically recreate some lost clipped Red detail from the G & B channels, but I'm not at my office and can't remember the adjustment (play with it and you'll see how it works in situations where only one channel is clopped)

3) use a splitter/combiner node, delete the 2nd & 3rd (G&B) nodes and apply SNR luma only to the R node, and that will clean it up. (Remember that chroma NR will not work because you're applying it to a monochromatic signal.)

Thanks for the hints,

I'll try to recover the red channel from the other two or the luma because it is really blobbing and wobbling and a simple denoise on the channel cannot fix it at an acceptable level.

Cheers!
Umberto

You can try a color space transform or gamut limiter plugin from the OpenFX library. Watch this video for more information: