Horizontal Lines When Adding Noise Reduction

Hello!

My co-worker and I (both on Mac Pros with the same specs, listed below) have both been having issues with DaVinci Resolve's noise reduction. No matter what project, we experience either horizontal lines, disappearing image, or a white partial border. Images are attached, but does anyone have any ideas why this maybe happening?

Specs:



Horizontal lines (seen on talent's skin) after adding Spatial NR:


Image disappeared once Temporal NR was added:


Hard to see, but white border on right side and bottom of image:



Thank you for any help!

Which hardware (CPU, GPU, RAM, disk I/O speed)? What specific version of Resolve? What OS? What source material? What timeline resolution? What framerate? Which GPU drivers are installed? What format are you trying to render to?

And what are your specific settings used for NR? I find splitting up SNR into Luma-only and Chroma-only seems to help, since the Y settings tend to soften the image.

I've never seen horizontal lines get into an image. What format is the source material? Could this possibly be an interlaced problem, or maybe something due to high compression?

[Dwaine Maggart]

Noise reduction on 6,1 MacPro's is prone to artifacts, generally random horizontal colored hits the image. But that's not what any of your images are showing.

There is an OS issue in Big Sur that causes artifacts with Resolve Spatial Noise reduction on 6,1 Mac Pro systems. That's what you are likely seeing in the skin. The only current solution would be reverting to Catalina.

Not sure what would cause the Temporal NR issue with most of the image disappearing. Do you have other OFX in use on that shot? What timeline resolution?

By default, Resolve should be using Metal GPU processing mode. If you have weird issues like this, you can try forcing it to OpenCL and see if that helps anything. Do that in Resolve Preferences - System - Memory and GPU. Uncheck Auto in GPU processing mode, and select OpenCL. Save the prefs. It will take a Resolve restart before the change will take effect.

Which hardware (CPU, GPU, RAM, disk I/O speed)? What specific version of Resolve? What OS? What source material? What timeline resolution? What framerate? Which GPU drivers are installed? What format are you trying to render to?

And what are your specific settings used for NR? I find splitting up SNR into Luma-only and Chroma-only seems to help, since the Y settings tend to soften the image.

I've never seen horizontal lines get into an image. What format is the source material? Could this possibly be an interlaced problem, or maybe something due to high compression?

Not sure if you can see my screen grabs in my post above, but Late 2013 Mac Pro, 3.5 GHz 6-Core Intel Xeon E5, 64 GB 1866 MHz DDR3, AMD FirePro D500 3 GB, running Big Sur version 11.6. DaVinci Resolve 17.3.1 Build 5. It's showing in the preview window and on export.

Thanks for the suggestion. It happens still when we split those up. It's most noticeable when mode is set to "Faster".

It's happened on a wide variety of formats... ProRes 422 HQ, RED, H.264, anything.

Noise reduction on 6,1 MacPro's is prone to artifacts, generally random horizontal colored hits the image. But that's not what any of your images are showing.

There is an OS issue in Big Sur that causes artifacts with Resolve Spatial Noise reduction on 6,1 Mac Pro systems. That's what you are likely seeing in the skin. The only current solution would be reverting to Catalina.

Not sure what would cause the Temporal NR issue with most of the image disappearing. Do you have other OFX in use on that shot? What timeline resolution?

By default, Resolve should be using Metal GPU processing mode. If you have weird issues like this, you can try forcing it to OpenCL and see if that helps anything. Do that in Resolve Preferences - System - Memory and GPU. Uncheck Auto in GPU processing mode, and select OpenCL. Save the prefs. It will take a Resolve restart before the change will take effect.

Thank you! Didn't know about the OS issue so maybe that's it. I did not have any other OFX, just some color nodes. Even with those disabled, the issue is still there. 1920x1080 timelines.

Whenever I try to change it to OpenCL and restart Resolve, clips do not appear and I am unable to play through/see anything.