Q: There is no connected camera

I just purchased a Macbook Pro 13-inch (mid-2012) about a month ago.

Since, I bought it, built-in Facetime HD camera working fine with Mavericks.

last two days ago i just upgrade to El Capitan after that Facetime showing "There is no connected camera".

I've tried lot of tricks like sudo killall AppleCameraAssistant;sudo killall VDCAssistant but still showing like that

Please help me on this