ACES 1.3 Reference Gamut Compress Issue

I'm using Davinci Resolve Studio 17.4.6 on MacPro 7,1 with 6800xt GPU (Metal Mode). I have an issue using ACES 1.3 with reference gamut compress set to on, there are weird colorized mosaic across the footage as shown in attachment (Shot on Alexa), this happen in every shots and projects I have tried. A resolution I found is to change GPU Mode to OpenCL but it is very slow on my computer, so I assume that it has something to do with Metal processing mode. Anyone found similar issues ?

Same issue. Rolling back to 17.4.2 helps but I wish for this to be fixed going forward.

I’ve never seen anything like that on my Mac Pro 2019 with Pro Vega II MPX card under ACEScct 1.3. Have you tried setting the reference gamut compress Off? Did it make an improvement?

Same issue. Rolling back to 17.4.2 helps but I wish for this to be fixed going forward.

I've just updated from 17.4.2 to 17.4.6, guess I need to roll it back for now.

I’ve never seen anything like that on my Mac Pro 2019 with Pro Vega II MPX card under ACEScct 1.3. Have you tried setting the reference gamut compress Off? Did it make an improvement?

The issue is gone when set reference gamut compress Off, but I really need this function for projects I'm currently working on since it the best way to handle overblown blue LED lights.

I've found a similar thread.
viewtopic.php?f=21&t=152615

The same issue seems to be persisted since 17.4.3 on RX6000 Series GPU.

The issue is gone when set reference gamut compress Off, but I really need this function for projects I'm currently working on since it the best way to handle overblown blue...

Those dreaded supersaturated LED lights! I’ll need to deal with those next month so I hope the issue has been corrected in Resolve 18.

Does the same issue arise when using an ACES Transform node instead of project wide ACES management? If not it might be a suitable workaround for the time being.

ACSES seems to be sensitive to those random issues (math behind/around it is still not polished). They are so annoying and without QC you may produce such a "bad" master.
Funny enough that in my case gamut compress was actually solving problem, not causing it. It was very simple project- just HDR to SDR conversion.

I’ll be able to investigate in May, doing a music festival at the end of the month. I expect to be able to get a sense for problems ahead of that when trying the beta of Resolve 18.

Hi

I want use Acescct I.3 see artefacts (black and white pixels) it only on new Mac pro with metal (Big sur and Monterrey).... but Linux (Centos 7) I see perfect the video.... all over Davinci Studio 17. I checked 18 build on Mac and had the same problem....

Would you be so kind to post some sample screen grabs that illustrate what artifacts you are seeing. Good if you also post the ACES settings in use.

I didn’t notice a problem with the music festival footage or more recent shoots but it’s always possible I’m just not looking closely enough.

I've updated the latest Davinci 18.1.4 and MacOS 13.2.1, no luck though. The same artifacts still carry on. Now this is the real issue for me since I need to work on Alexa 35 Footages so I cannot roll back to 17.4.2 which not support Alexa 35. I wonder if this only happen to 6800xt GPU or whole Navi 21 Series, I wouldn't mind upgrade to 6900xt if it solves the issue.

Painful, but you might simply go with OpenCL since that works for you. It does seem to be a problem with the 6800XT, but no guarantee the 6900XT is better. Good you’re On Resolve 18.1.4 now.

I recently reverted to DaVinci Resolve YRGB Colour Managed to create some short videos for public viewing from last year’s festival for promoting this year’s folk festival (posted in the Cinematography forum in the Official “Look what I shot” forum). I’m just about to redo all my videos that way as it seemed to be working well. I used to use ACES for all my work. I could try both ways this week and see if one appears better than the other.

I also decided to stop doing gamut compress. I have plenty of the saturated LEDs in frame and I’ve stopped fretting about how ugly they can make the shot. Occasionally I get better looking results by turning down saturation and cranking temperature or tint to offset the unnatural skin tones which worked well for me (check out the first song in Promo A of the aforementioned videos I just posted.

I found threads talking about the ACES issues with 6900xt on Metal too, so I guess all Navi 21 cards on Metal has the same problems. I do hope they fix this issue soon.

The best workaround for me now is to use Github ACESGamutCompress DCTL which do its job just fine, though the integrated one has noticeably better tonal gradation after compression.

Also having issues with black/white blocks randomly appearing on the image with a RX6900XT in Metal with Resolve 18 when using ACEScct. Issues disappear if I disable the 6900 and render on an RX5700.

The way the issue appears in my testing is:
- RX6900XT is used for GPU processing
- GPU processing is set to Metal
- Color science is set to ACEScct
- ACES reference gamut compress is enabled (although other image quality issues can also happen with compression disabled)

I'm mostly having issues with Alexa 35 ProRes media, but it can happen with pretty much any media. And I think it might be related to specific saturation levels.

I also have an issue with white pixels appearing in Alexa 35 footage shot at high ISO if Colors science is set to ACEScc and "Apply resize transformations in" is set to Timeline. That one doesn't seem to be related to the GPU, though, but it is annoying.

Have you all contacted BMD support? When I contacted them they told me they weren't able to replicate my issue, but I would think that if enough people contact support directly the issue will get properly looked at.