I want to create a simple background video for a Lofi video like this. Besides being comical, the elements seem quite simple: moving background, some smoke and train movement. I tried something like that with falling snow back a window, but it does not even start to render. Or it does, but never leaves 0%. I got some .png files to make the window transparent etc. and then move them with keyframes. Falling snow is done by adding a prerendered video of snow and removing the black background. I tried performance enhancing settings and have a quite powerful CPU and GPU. Is there perhaps something I am doing that Davinci just doesn't like? Do you have other thoughts of why this does not work?
I don't think I can help with your specific render issue without more description, but the method you describe doesn't really seem like a very good way to do it in Davinci Resolve.
If you have a still image, you're probably better off masking out the transparent window with polygons right in DR than using a separate png file.
Adding snow would be better (and more realistic) if done in Fusion with Particles (pEmitter & pRender nodes). Here's a tutorial video specifically for making snow:
(This may not be the best one, just the first one I found. There lots of Fusion tutorial videos out there.