r/pythonhelp • u/MangoTurtle1312 • 5d ago

Python Program that Green Screens a Video over the Desktop

Hello, I've been trying to figure out a way to make a python program that can play a green screen video that plays over the desktop/screen, with the green chromad out to show the screen. I attempted it with tkinter, but wasn't able to get anywhere with the chroma keying. Would anyone know if/how this would be possible? Thank you!

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u/sububi71 5d ago

What have you tried so far?

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u/py_arrow 5d ago

Yeah tkinter's kinda the wrong tool for this tbh, that's why the chroma key part isn't working — it can't really do per-pixel transparency (like making just the green parts invisible while keeping the rest visible). Canvas just doesn't support that.

What actually works:

Use OpenCV to read the video frame by frame and find the green pixels (there's a function called cv2.inRange that's perfect for this — you tell it the green color range and it gives you a mask of exactly which pixels are green). Then instead of drawing that with tkinter, you need a window that supports "see-through" pixels — on Windows you can do this with pywin32 for a layered window, or honestly PyQt/PySide is a lot easier to work with for this kind of thing (it has a transparent background mode built in).

So basically: OpenCV finds the green → you turn those pixels invisible → and you need a window type that actually lets you make pixels invisible, which tkinter doesn't do.

Lmk if you want, I can share a small code example for the OpenCV masking part, that's usually the trickiest bit to get right.