Maybe what works for me would work for you to enable watching a video. I set all
three power save options in desktop settings to 120 minutes.

Something else to try depends on a config file in which to put it, either
in /etc/X11/xorg.conf or a file in /etc/X11/xorg.conf.d/, included in
Section "Monitor":

		Option	"DPMS"	"off"

People using DE's (e.g. TDE) normally don't use cmdline utilities for controlling
X behavior, unless within startup scripts. The only one I ever use in a startup
script is xrandr. Xset has never been my friend.
-- 
Evolution as taught in public schools is religion, not science.

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/