FaceTime has not received any video from the connected camera. Fix without restart.

This is a fix to FaceTime not having video from your camera.

Symptoms: upon starting FaceTime you have a black screen instead of a stream from your camera, after some time a message "FaceTime has not received any video from the connected camera. Restarting your computer may fix this issue" appears.

Solution:

1. Quit FaceTime, then
2. Open Terminal, then
3. Execute the following command as a standard user (no privilege elevation required):

kill $(lsof | grep "AppleCamera" | grep avconfere | awk '{ print $2; }')

Start FaceTime.