In Firefox on Ubuntu 14.04, just upgraded from 13.10, I can't make any video full screen without issues. When I tried it usual do this: video freezes, and sometimes you can hear the audio, but not always.
I have the same issue with Ubuntu Gnome 14.04 but I can specify it a little bit. I can have fullscreen once, once I come back by hitting the Esc key or clicking the button, this error occurs. Killing the "plugin-container" process lets the flash-plugin crash and after reload you can give it another try. For Youtube there is a workaround by switching to HTML5 instead of Flash. Go to https://www.youtube.com/html5 and mark that you want to use HTML5 whenever possible. To get the H.264 codec working in 14.04, you have to use a PPA as the package is not (yet?) available in the official repositories. Once you managed that at least Youtube will work fullscreen.
This is not a "fix", but a workaround. I found it on the Arch Linux Wiki (where they also have solutions for other browsers). That said, it worked flawlessly for me.
Install the devilspie package (you'll need to have Universe enabled):
sudo apt-get install devilspie
Create a folder called
.devilspie inside your user directory, and a configuration file named
flash-fullscreen-firefox.ds in there:
mkdir ~/.devilspie nano flash-fullscreen-firefox.ds
Then add the following content to that file and save it:
(if (is (application_name) "plugin-container") (begin (focus) ) )
To make it work NOW:
Run devilspie. Press Alt-F2 then type
/usr/bin/devilspie followed by Enter.
To make it work upon login to your system:
- Press Alt+F2 and type:
gnome-session-propertiesfollowed by Enter.
- Press the Add button and insert Devilspie inside the field name, and
/usr/bin/devilspieinside the command field.
- Press Add, then close Startup Application Preferences.
- There is no step 4, you're done!