hacksider/Deep-Live-Cam ? reverse-engineered prompt

I want to build a real-time face-swapping app that works with my webcam. It should have a simple GUI where I can just upload a single picture of a face, select which camera to use, and hit a "Live" button to start. When it's running, it should show my webcam feed but with my face replaced by the face from the image I uploaded, all in real time.

I'd like a few extra features, too. The app should be able to handle multiple people in the video, swapping each of their faces simultaneously. It would also be great to have an option to keep my original mouth visible over the swapped face so that talking looks more realistic. Besides the live camera feed, it should also work on video files I load from my computer. Please build this using Python and make sure it can use my GPU for acceleration, whether it's an Nvidia card on Windows or an Apple Silicon Mac.