my mac camera doesnt work for more than a few seconds on facetime - totally fine on zoom, google meet, etc

Hello hannahbfit,

Thanks for choosing the Apple Support Communities. It sounds like your webcam isn't working on FaceTime. We have a few steps to take which will help us isolate and eventually resolve the issue. Let's take a look at each.

1. Test in safe mode. This will let us know if this issue is caused by a third party application. Here is how to log in using safe mode: How to use safe mode on your Mac - Apple Support
2. Test in a test user. This will let us know fi the issue is system wide or specific to this user. Here is how to test in a test user: Change Users & Groups settings on Mac - Apple Support
3. Try the steps outlined in the resource you came to us from: If your built-in camera isn’t working on your Mac - Apple Support

"Check the camera indicator light

If the camera indicator light next to the camera flashes green on your Mac notebook, contact Apple.

Update your software

Make sure your software is up to date.

Check Screen Time settings

If your Mac is using macOS Catalina and you use Screen Time, make sure your camera is turned on and apps that use the camera have time available.

1. Choose Apple menu  > System Preferences, then click Screen Time.
2. Click Content & Privacy in the sidebar, then click Apps.
3. Make sure the checkbox for Camera is selected. 
4. Click App Limits in the sidebar. If you need to use your camera with an app in the list, make sure the checkbox for Limits is not selected.

Give apps permission

If your Mac is using macOS Mojave or later, choose which apps can use your built-in camera:

1. Choose Apple menu  > System Preferences, then click Security & Privacy.
2. Click the Privacy tab, then click Camera in the sidebar.
3. Select the checkbox next to the apps that you want to use your camera in. You might be prompted to quit and reopen an app before it can use your camera.

Try another app

Try to use your camera in another app. For example, if you can't use your camera in FaceTime, open Photo Booth.

Reset the SMC

If you still can’t use the built-in camera and you have an Intel-based Mac, resetting the SMC might help. Learn how to reset the SMC on your Mac.

Learn more

If you can't connect to FaceTime, learn what to do if FaceTime isn't working on your Mac."

Cheers!