yeap, got that problem some months ago, hardware defective, i assume when it's buzzing you can't focus well too right? if so then that's the same problem that i had, go to sc and prove that problem to them on the spot, they will fix that up for you if your note 4 is still under warranty

That happened to me too that time, so i keep trying at home, while recording using camera, then one thing i found out that it would trigger the buzz, is that when you open up the camera app, if it's not buzzing, then exit the app, kill it in the background, then when you are about to reopen the app, point your phone's camera to a darker place, ie under the table, or point to a dark surface table, or even cover with your palm, then open up the camera, see if it's buzzing.

i assume yes, and glad that you can make it work, now time to go to SC to reproduce the problem

you need to update Google Play to the latest version for MM