Custom ColorDifference Keyer in UE

I have cleanplate and source video and need to setup Color Difference keyer in UE

I see DiffColorKeyer in blueprints and also M_ColorDifferenceKey and M_SinglePassDiffColorKeyer in Composure materials, but have no idea how this works
Also i’ve read this article -…aterial-in-ue4 but still don’t understand how to combine 2 images (cleanplate and source)
Any blueprints and links will be perfect.

You might check out He has 2 greenscreen composure youtube videos to step through the basics…

Yes, this was a first videos, that i’ve check. Still have no idea how to use cleanplate for difference keying

Just to be clear- are you talking about greenscreen or difference matting?
I sent the link of greenscreen setup. (and typically no need for a greenscreen)
Difference keying is comparing pixels of 2 images and extracting the pixel difference.
Coded in C++ in non Unreal apps but never dealt with Blueprint/Materials.

What they’re calling color difference isn’t a true difference key. Suggest duplicating the Over material and simply replace Add with a Subtract and pass the 2 images in directly. Then you’d want to clamp the results and make as a grayscale for the actual matte. (Ideally difference would be in HLS or other color space than RGB but it’s a start). I’m fairly new to Unreal so haven’t done it myself.

My bad =)
This is my current progress

And blueprint


Decent results. I guess the question is whether you want to use it also without the greenscreen at some point.

I am a professional vfx comper diving now into realtime production, I can built my own keyer as a material but was wondering whether it is possible to use the already good enough keyer (at least for previz) from Composure on an image plane? Seems a lot of people tried but didn’t get it… any ideas? Thx, Mark