Tried all the above, neither worked for me. Personally, the best YouTube
experience you can get on Trisquel is with a program called SMPlayer YouTube
Browser (it's not perfect though, because it does not support WebM). To
install it on Toutatis (Trisquel 6.0), open a Terminal window
([Ctrl]+[Alt]+[T]), then write:
sudo add-apt-repository ppa:rvm/smplayer
sudo apt-get update
sudo apt-get install smtube
Then start the program (from Sound & Video), click on the button with a
screwdriver on it, and set player to MPlayer (and if you have a slow
connection, you can also set quality to normal). Now just search for your
favourite video, double-click on it, and enjoy the playback. Btw, you can
switch to fullscreen anytime by pressing [F].
Enjoy!
