LogC > SceneLin / ACEScg Noise Issues

Got a bit of a weird thing here, or maybe not, but haven’t seen it before.

Camera footage: Alexa Mini, LogC (v3-EI800) / Alexa Wide Gamut

When I input transform the footage to Scene-Linear rec709/sRGB vs. ACEScg and denoise using Neat Video, I get much noisier results with Linear than ACES. Lots of boiling and artifacts as well.
Tried making my own profile as well as using the generic one but it’s always “worse” when working in Scene-Linear rec709/sRGB.

Footage has not been cached and I’m doing Colour Management using a node in BFX.

Any ideas?

Neat doesn`t like negative values when doing its job. rec709 has a much narrow gamut compared to the original Alexa or ACEScg, and when converting the original gamut to something narrow you get negatives. The narrowest target gamut will lead to more artifacts.
The solution is to convert to Alexa Wide / Linear, denoise, then convert to ACEScg or rec709 / Linear, or denoise in logC and then convert.


Thanks, much appreciated!

Might be a long shot but have you looked at the different gamma settings in neat?


Yes, thanks!