UNR Bug

I'm seeing a bug with UltraNR in the blue channel when I use the HDR Rec.2020 Intermediate as the Color Processing Mode. (Because Automatic Color Management also uses this mode, the bug appears there as well.)

2020 Intermediate.png (43.51 KiB) Viewed 458 times

Anything above 0 for the Chroma of UNR will induce the bug (under certain lighting conditions.)

Blue Error.png (116.07 KiB) Viewed 456 times

Using DWG for Color Processing works fine.

Blue Clean.png (99.35 KiB) Viewed 458 times

Studio 19b2 for Windows.
RTX 3060 12 GB
Gaming Driver 552.44

Maybe those areas are out of gamut for rec2020, go negative and do wonky stuff in NR algo.

I thought of that, but I'm not sure.

Rec.2020 HLG seems to work. And it's only when I apply even the slightest bit of Chroma denoise from UNR that it occurs. Nothing in Luma will trigger it.

i've not been able to replacate this, but i also work in ACEScct pretty much always
+1 to Hendrik's thought that it might be neg pixels when used in a gamut limited timeline

if I have to point a finger, that is "above 1.0000 error" (truncation) as in not float point....

I tried all the Rec.2020 options for Timeline color space.

Only "Rec.2020 Intermediate" showed the issue. Here are some scope views. You can see the clipping in both blue and green channels at 1000 nits in the third image, despite Working Luminance being set to HDR 4000.


DWG Intermediate

UNR Scopes DWG.png (260.86 KiB) Viewed 201 times

Rec. 2020 Gamma 2.4

UNR Scopes 2020 2.4.png (260 KiB) Viewed 201 times

Rec.2020 Intermediate

UNR Scopes 2020 Int.png (268.57 KiB) Viewed 201 times

This time I'm getting some very ugly results even when using DaVinci Wide Gamut.

DWG Timeline.png (78.05 KiB) Viewed 87 times

Here's without UNR.

UNR DWG Clean.png (395.73 KiB) Viewed 87 times

And with...

UNR DWG Noise.png (429.05 KiB) Viewed 87 times