IPP2 in RCM

[Alan Gordon]

Has anyone noticed that R15's implementation of the IPP2 gamut mapping in Resolve color management can cause banding in the highlights?

I was testing it out and was noticing some weird behavior in the image that I do not see when using the RCX generated LUTs.

I can pull stills if need be.

 

[rand thompson]

Alan,


What settings do you have for "Camera Raw".

And do you have these "Color Managed settings"

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And are you using "Trilinear" or "Tetrahedral" interpolation?

 

[Alan Gordon]

Rand you misunderstand. I am having no issues with the LUTs. Only when using Resolve Color Management.

 

[rand thompson]

Alan,


I understand what you said, what I was saying is what "bit depth" do you have " Camera Raw" set to, 16?, what interpolation method are you using, tetrahedral? and was your project set at "Full Res.Premium" and exported at "Full Res. Premium", or did you use proxy files while editing ?

 

[Alan Gordon]

Yes, it decoding is set to 16 bits, full res premium. Performance mode off. Tetrahedral LUT interpolation, but using RCM it should not affect.

 

[rand thompson]

Okay..Understood. Hmm, don't know what's going on then, do you mind posting a .r3d frame from the problematic file? I see the banding on his arm in the example you posted. This may be a problem Blackmagic needs to look into.

 

[rand thompson]

might have to go back to the old method I was telling another member in another thread not to use for a preset IPP2 output Transform. Hope its something simply that can correct this problem in the settings.

 

[Alan Gordon]

I cannot share that clip as I do not have the rights to it, but it is not isolated to that one clip. Others show the issue as well. Try those RCM settings and adjusting the offset up and down and look at the scopes. Something very strange is happening.

Edit: And yes I know how to use the LUTs as Output transforms, just would be good to squash a bug if it's there!

 

[rand thompson]

Alright then, will do!

 

[rand thompson]

Alan,


I used the "Davinci YRGB Color Managed" settings posted above, however nothing in the Scopes really "jump out" at me and I could never get anything to induce banding, but then again I very rarely use "Offset" to correct anything. Could you help me to see what you are seeing in your scopes that has alarmed you?

 

[rand thompson]

Alan, another thing to check are your "project" settings under "Camera Raw"

Do you have these, which you will need to change before switching to the "Davinci YRGB Color Managed" "Red IPP2 Gamut Mapping". They get 'Greyed out" after the "Davinci YRGB Color Managed" workflow gets selected.

Or Do you have these, which are the default "project" settings when you start up a new project in resolve ,which will get "Greyed out" after the "Davinci YRGB Color Managed" workflow gets selected.

 

[Alan Gordon]

Rand, I think you have a misunderstanding of how RCM works. The reason those controls are greyed out is because when you are working in RCM, Resolve takes the camera linear data and transforms them from there. In RCM, just as in ACES, there is no need to select a color space or gamma curve in the development settings, because Resolve goes straight to the source. Changing those controls first does nothing to the image. Controls that are not greyed out do affect the development in color managed spaces.

Additionally I would like to point out that you incorrectly have log3g12 selected in the first image and not log3g10.

What you should see as you adjust luminance in RCM with IPP2 Gamut matching is a sort of plateauing/stair stepping that happens on the waveform.

 

[rand thompson]

Thanks for catching that, Log3g10. Yeah, still learning about the color managed workflow and have never used ACES, so if you say that's how it work, I believe yah.