I have a c270 Logitech webcam and I just noticed, that the LED is on, indicating that the webcam is recording. However there is no application (I would be aware of) using the webcam. So how do I find out how and what activated it?
System is ubuntu 12.04 with the 3.4 rc 4 kernel
You can use lsof to track back what is accessing a file. I, personally, have a homebrew app that uses lsof and an underlying API to let me know when something opens my webcam.