macbook pro – system camera or external camera not working in facetime – No video “Facetime has not received any video from the connected camera”

Leaving this here, in case there are others facing the same issue. 

Sometimes after sleep, the external camera won’t work within facetime. It works fine in skype, zoom.

Reboot fixed it every time, but to save the restart time what worked for me was below command:

“sudo killall avconferenced”

Those commands “sudo killall AppleCameraAssistant;sudo killall VDCAssistant “, found on other posts online didn’t work for me.

The system is macbook pro 2013 , late retina, macos catalina