Rendering into a specified rectangle or area with kmssink

I am struggling to find a solution to render the output of kmssink into a defined region of the screen. Fullscreen works, but i want to render with a defined resolution in one corner of the screen.
Is this possible? If so, any help is appreciated.

would compositor work?
https://gstreamer.freedesktop.org/documentation/compositor/index.html?gi-language=c

Hi! Thank you for your reply. I will look into it and test.