How to record the live streaming of YouTube?

I thought it would be very easy to find but, apparently, that is not the case. Since yesterday I am looking for a software that records YT live. FDM does not work. IDM does not work. VLC only records video and not audio. The Firefox extension called "FDV" was found, but it does not work. It seems that Camstudio works but apparently, there is a virus in it.

Please help