Blackmagic Forum

When using Luma setting in "Spacial Threshold" I get a crazy snow storm effect across most of the center of the screen.

I'm lost.

Jim Simon wrote:I'm lost.

It did not happen to you or you are not able to find it?

WahWay wrote:When using Luma setting in "Spacial Threshold" I get a crazy snow storm effect across most of the center of the screen.

We need some more details. What level are you using? What source material? What system are you using (CPU, GPU, RAM, OS, etc.)?

Generally, I tend to split Spatial NR between Luma and Chroma Thresholds, and I try to keep Luma fairly low and push Chroma fairly high. You can make a case that Better or Enhanced modes yield better results, but they tend to be somewhat processor-intensive. I'll sometimes combine TNR with SNR, but there are occasions where SNR does too much damage. It's also possible to target specific parts of the image (shadows-only or highlights-only) using a key, and then apply the NR just to those and leave the rest of the image alone.

An audio engineer I've known for years once explained to me the need for a "Taste+1" philosophy: "move the knob where you think it should go, then back off 1." The idea is, your initial instincts for something NR may be too much, so come down a little bit to avoid the artifacts.

I've been using cDNG, any values in Luma will trigger it, won't happen immediately but you will notice when you try and play preview. It also happen in Chroma but to a lesser degree. I use to use this feature without issue in previous version of Resolve.
Also notice with the above this tend to happen when the Project Settings > Timeline resolution is set higher than 1920x1080 such as UHD

This problem does not happen with BRAW, only with cDNG files so far what I have tested.

I have no clue. We haven't done a Cinema DNG project in more than 18 months, so it's been awhile. I'd suspect a GPU problem, but it's hard to say.

My suggestion for a workaround would be to invest in Neat Video and use that instead. I believe it's about $150, and it does an impeccable job when adjusted very carefully. Be warned that it's very slow and processor intensive. A demo version is available, so you'll be able to see if it adds any problems to DNG in a test.

It would'nt be a GPU problem because I could frame grab and export the file with this problem as I have done here. When it happens the preview flickers too and the audio goes hay wire. Its a bug I hope gets fixed

This problem has been fixed again in Resolve version 17.0