Fusion bug in DR 19.1.2 and get worse in DR 20.0

Hello everyone, until a few days ago fusion was working normally for me, but suddenly when I enter a clip in fusion it looks different from the normal Color of my clip and it goes extremely choppy or the playback don't work at all, and from time to time I get red lines as if It was a something missing. It's not because of my color workflow because these are the same clips that worked fine for me before, also because sometimes it gets fixed by restarting Davinci without me doing anything, I just enter Fusion after restarting davinci and everything is fine.

I already tried to reinstall Davinci from scratch but nothing. This also happens with other projects that were going well for me before. In the title I put "Potential Bug" because perhaps it is something with the Nvidia drivers that were also recently updated along with Windows. I leave the Log file hoping to find help or people who have the same bug.

Here is a video of what happen when I enter to fusion, for better understanding. In the second 47 the red lines appears (use the preview, no need to download the video):

https://drive.google.com/drive/folders/ ... EXC1__8kCy


And a photo in the attachment.

If you turn of view lut in fusion, does it also happen? What color management set up you are using for the timeline?

If you turn of view lut in fusion, does it also happen? What color management set up you are using for the timeline?

I'm using Davinci Color Managed (photo in the attachment). For Color processing mode "SDR Rec.709", and for output "rec.709" for color and "Gamma 2.4" for gamma.

When I turn off the Fusion LUT, everything runs smoothly, thanks!! I uploaded another video to Google Drive so you can see the result ("FUSION Lut Test" https://drive.google.com/drive/folders/ ... EXC1__8kCy).

When I turn Fusion LUT back on, everything stutters and go with errors again.

It's strange because the same thing happens in other projects where I used Fusion before and they worked fine until a few days ago that I update Davinci, Nvidia drivers and Windows. This is sometimes fixed by restarting Davinci and everything works fine, then I restart again and the same error can appear even in new projects (only for Fusion, in the editing page everything works fine)

I'm using Davinci Color Managed (photo in the attachment). For Color processing mode "SDR Rec.709", and for output "rec.709" for color and "Gamma 2.4" for gamma.

When I turn off the Fusion LUT, everything runs smoothly, thanks!! I uploaded another video to Google Drive so you can see the result ("FUSION Lut Test" https://drive.google.com/drive/folders/ ... EXC1__8kCy).

Thanks. Yeah. I've seen this now, few times, posted by other people here on forum, same red cross over checkboard. But I was not sure how to reproduce it or why exactly it happens. I couldn't reproduce it until one time, but I didn't write down what I did at time. So it could be workflow not bug issue, however it would be nice if blackmagic added more information to know what to watch out for.

When you switch to a channel in the fusion viewer that does not exist in a node, such as Z-channel , you usually get same red cross with checkboard, but also a message that z-channel is missing.

But in your case, there is no message, so its hard to know what it means. Probably its related to color management and viewer lut connection , somehow,

When I turn Fusion LUT back on, everything stutters and go with errors again. It's strange because the same thing happens in other projects where I used Fusion before and they worked fine until a few days ago that I update Davinci, Nvidia drivers and Windows. This is sometimes fixed by restarting Davinci and everything works fine, then I restart again and the same error can appear even in new projects (only for Fusion, in the editing page everything works fine)

Can you try one more thing, just for test. Turn on "Automatic color management" checkbox and do as you did before. See if that makes a difference.

I try to isolate the problem last time someone posted about it, but they never stayed on forum long enough to get to the bottom of this, but at least now I have seen it before, so I notice some patterns. Fusion viewer lut on and off, obviously is somehow linked and probably that is related to color management. I'm just not yet sure how to reproduce the problem reliably on my machine so I can figure out if its a problem of workflow or a bug.

P.S. Also try for testing just regular Davinci YRGB for manual color management.

Ok I notice some things now.

1- In the "Davinci YRGB" color science the bug has been fixed!! Everything works fine and smooth.

2- In "Automatic color management" everything is the same. With bugs and errors.

3- When I try to move the window when Fusion Lut is activated in Davinci Color Managed, Davinci goes very slow, the window doesn't move until a few seconds pass, everything is very choppy.

4- The bug also occurs in ACEScc and ACEScct (ACEScc was the workspace I was working on this project until I saw the bug, ACES1.2 that output to Rec.709)

5- The bug and choppy playback occur with all kind of videos, .braw, .mp4, mkv, even with image sequences like .exr.

6- In the "3d world" nothing happens, everything runs fine and smooth, so maybe it's something about how Davinci handles color and 2d stuff in the "Color Managed" color science and in ACES.

7- Something interesting happened when I was recording, I turned on Fusion Lut and at the same time Davinci saved the project, then the Lut was applied only for that moment (although everything was still slow and choppy), then later I exited the clip and re-entered another one and all was the same again, slow and buggy.

I've already uploaded a third video to Google drive again, trying the things I mentioned above. I tried some of them off camera so some of the point won't be in the video.

"3 - Automatic color management" https://drive.google.com/drive/folders/ ... EXC1__8kCy

Interesting tests. I am still not sure what is the cause. lets assume its a bug. I think I've started to notice posts about it when Resolve 19 was released. It would be nice to hear from developers if they have some thoughts or confirmation that is a bug. I have a hard time replicating it, so I can't do my own tests. Maybe its something only happening with particular hardware configurations. If I recall, last time it was mentioned on windows, and I am also on windows. And I think you are also on windows well.

Interesting tests. I am still not sure what is the cause. lets assume its a bug. I think I've started to notice posts about it when Resolve 19 was released. It would be nice to hear from developers if they have some thoughts or confirmation that is a bug. I have a hard time replicating it, so I can't do my own tests. Maybe its something only happening with particular hardware configurations. If I recall, last time it was mentioned on windows, and I am also on windows. And I think you are also on windows well.

Yess, I'm using Windows 10. I hope the developers see this post to figure out what's going on. For now, I'll be working on "Davinci YRGB" until the issue is fixed. Thanks for all the help!!

Just in case I'm putting my specs here, since I have no idea if the davinci log does it. This way I'll help more to find a solution.

Operating System
Windows 10 Pro 64-bit

CPU
AMD Ryzen 9 5900X

RAM
32.0GB Dual-Channel DDR4

motherboard
Micro-Star International Co., Ltd. X470 GAMING PLUS MAX (MS-7B79) (AM4)

graphics
XV272U (2560x1440@144Hz)
XV272U (2560x1440@144Hz)
4083MB NVIDIA GeForce RTX 4090 (Gigabyte)
Nvidia Drivers: 561.09 (also occurs in new drivers)
(and this one just in case - CUDA Version: 12.6)

Storage
223GB KINGSTON SA400S37240G (SATA-2 (SSD))
7452GB Western Digital WDC WD80EFBX-68AZZN0 (SATA)
931GB Seagate ST1000DM010-2EP102 (SATA)
5589GB Western Digital WDC WD60EFAX-68JH4N1 (SATA (SSD))
465GB KINGSTON SA2000M8500G (SATA-2 (SSD))
931GB KINGSTON SA2000M81000G (SATA-2 (SSD))

Optical Drives
No optical disk drives detected

Audio
Focusrite USB Audio

Ok, now it got even worse in DR 20.0. Now it doesn't work anything, even after disabling the Fusion LUT. And if you connect any node to another node, DaVinci freezes and doesn't let me do anything, not even click the close, minimize or "File, edit, trim etc..." buttons, and is not a typical windows freeze that show that white overlay with the windows dialog, it just freeze. Automatic things like autosaving still work, but DaVinci doesn't register any new user input after connect nodes, I can't change to edit mode again. And if I change the color science to Davinci YRGB the program freezes too so now I dont have any workaround for this

I update a fourth video in google drive and diagnostic log in attachments:https://drive.google.com/drive/folders/1K4lUoLTWV5YNw6pMxd_VjrEXC1__8kCy

Since original post, at least on Resolve 19 I managed to narrow down the potential cause. It seems to be strongly related to color managed settings in resolve and viewer lut. When using non color managed settings in the project and doing manual color management with CST, no issues. Soon as color management is used, with most projects, sooner or later there is a red cross and laggy behaviour. For now I just do it all manually. After all I switch between Fusion studio and Resolve version of fusion very often and in fusion studio this is not an issue since there is not same system for color management, and manual set up is what I use. So its not a big deal to do the same in resolve. But it appears to be a memory leak of some sort in resolve when using color management system and fusion viewer lut. At least that is what I managed to narrow down so far and avoid the problem by doing color management, manually.

Since original post, at least on Resolve 19 I managed to narrow down the potential cause. It seems to be strongly related to color managed settings in resolve and viewer lut. When using non color managed settings in the project and doing manual color management with CST, no issues. Soon as color management is used, with most projects, sooner or later there is a red cross and laggy behaviour. For now I just do it all manually. After all I switch between Fusion studio and Resolve version of fusion very often and in fusion studio this is not an issue since there is not same system for color management, and manual set up is what I use. So its not a big deal to do the same in resolve. But it appears to be a memory leak of some sort in resolve when using color management system and fusion viewer lut. At least that is what I managed to narrow down so far and avoid the problem by doing color management, manually.

Yes! That’s what I thought too about the DR 19 issue, but now in DR 20, the error also occurs in DaVinci YRGB, not just in "DaVinci YRGB Color Managed" mode like it did before in version 19.That’s why I mentioned earlier that I don’t have any workaround to avoid this annoying bug if I end up upgrading to version 20.

I’ll probably have to do what you suggested,use Fusion Studio externally through VFX Connect Clip.

Now I'm not sure anymore if the issue in DaVinci 20 is related to color management only, or if it's something else or a mix of bugs in neural engine or in the Nvidia drivers, because the freeze behaves differently now. It's no longer just slow or laggy, just freezes. And other things that uses gpu work strange too.

Some of the new features in DaVinci, like the AI music extension are acting strange too. For example, the "Extend Music" function works great when I extend the full duration of a song, but when I try to reduce the duration of music, the program just lowers the volume in any random spot and music ends, no matter the track or the project, for reduce duration don't work. Sometimes it works only if I do it in Fairlight. Maybe I will report this as a bug in other topic becouse maybe is a different bug.

Everything feels weird lately, I miss the DaVinci 18.5 stability hahahha. Maybe I'll give Kdenlive a shot one of these days . But I'm never going back to Premiere, that's for sure

I forgot to mention that the error still occurs in DaVinci 19 even after reinstalling Windows and doing a clean, fresh install of DaVinci 19. So maybe it's a combination of drivers, a color management bug, and a specific PC hardware setup.