Facetime suddenly stopped showing video!

Perhaps after an update (though I'm not sure) my 2013 MacBook Air stopped showing me the other person's video when I Facetime! I know that it's my computer because I can facetime with these people through my iPhone and several different people have had this problem!

It's not the camera, as skype works fine, and when you go into facetime, the camera is working and showing me, and it can broadcast that to the other person (aka they can see me on facetime, but I can't see them!)

I have tried signing out of facetime, and my laptop is updated to the newest software, still the problem persists. Any suggestions?