攝像頭顯示黑屏 Camera is not working

我的MacBook Pro 攝像頭綠燈是亮著的，但是photo booth是黑屏。其他所有可視訊軟件皆如此。已試'sudo killall' 求解決方式！

My MacBook Pro camera is not working, the green light beside is on, but photo booth shows nothing (shows same in other chat apps), I tried 'sudo killall' already, nothing improved. need help, please~