Blackmagic Forum

I came across a problem with mixed clips on an unmanaged DWG (rec709 out) timeline in version 19. I had HD rec 709 and Sony log and Canon log files on a DWG timeline using an unmanaged workflow and CST's. The rec 709 footage was clipped in the highlights and I could not recover clipped data. I realize this likely doesn't have anything to do with other clips on the timeline but mention it for disclosure. For the HD r709 clips I had Superscale enabled with the Nvidia RTX/Ultra option and turning that off gave me access to the clipped highlights. Is this normal behavior? Is there a workaround that allows recovery of highlights and upscaling with the Nvidia rtx gpu?
Thanks
Dave

Interesting! It must clip those super whites for some reason.
Does the same thing happen if you use color management or use an input LUT/DCTL to convert your r709 to your working space?

I believe input luts and IDTs process before any sizing is done by default, but any node based things occur afterwards - so if the superscale doesn’t support superwhites then it would be clipped.

Yes, Rec709 footage I pull off my phone and DJI drone has highlights that exceed 100 IRE.

With no color management, You can see this if you enable extents on the Scopes and use gain to reduce a clip, you will see there was stuff above 100ire. I would love to hear someone smarter than me explain why.


Not sure about the V17 automatic color management, if it is smart enough to tone map this, I use CSTs. In your Rec709-DWG CST enable Davinchi tone mapping and set the custom input to about 130. This will compress the highlights in before it is brought to DWG so nothing clips, it will also sadly reduce your overall exposure.

For cLog3 footage from my Canon r5 it seems like 100ire is really as high as the input file goes, so you don't need do any such monkey business.

I tested with managed and unmanaged timelines, luts and cst's all with the same clipping behavior when using the nvidia rtx ultra option for superscaling. Interestingly the standard 4x superscale retains the data so my guess is as you said: the nvidia rtx superscale processing clips data. I might try a render in place and then the upscaling because I do think the result is superior.

What happens when you change the data levels in the clip attributes? Als chance of recording the highlights?