when using keynote, I can't use the camera and microphone at the same time.

I am trying to record myself on my slides. I can see a live view of myself, but when I try to record audio, the camera either freezes or goes blank. Sometimes the audio records, sometimes it doesn't. The camera is working, the microphone is working, but Keynote won't let them work together at the same time.

Everything is up to date, computer is 13" MacBook Pro, 2020.