Hello, I’m using Netrunner 12.12.1 updated until today, my problem was I couldn’t play no video, it just gave me audio but black screen, I tried a couple things but I fixed it with the following instructions
Open VLC Player
Go to Preferences – Video – highlight Output Modules and select X11 video output from the drop-down list.
Restart VLC Player.
I hope this helps someone with the same problem.