So far I couldn’t find an article helping me with this scenario:
Into a background (Video) I want to see a picture moving in from the bottom, eventually not occupying all of the screen, but only let’s say a third of it.
So it should look like a end title credit roll that leaves two thirds of the background untouched and gradually reveals the picture rolling up as viewed through a letterbox slot.
Ideally the picture would dissolve as it approaches the upper border, so no hard border visible.
I played with SPR, Opacity and crop filters, but don’t seem to get my head around it …
The filter you need is Mask: Simple Shape.
From what I deciphered from your text, this is what I came up with.
Or this
Source image locations in the comments section of the properties tab.
BINGO! This is what I was looking for. I decided to use the secod variant as it goes into my head more easily if the track with the moving part is above the static footage. It will take me some mulling over this filter stacking. I always get confused about what gets visible with these shapes that cut out and subtract and invert and what not… Thanks again @Hudson555x !