Screen turns off while VLC is playing movies in Kubuntu

Solution 1:

There are couple of settings that you should check in VLC:
1) Tools --> Preferences --> Show All --> Video --> Disable screensaver
2) Tools --> Preferences --> Show All --> Advanced --> Inhibit the power management daemon during playback
If both of this options are checked, you could try a simple wrapper script which disables the monitor modes that will power down, standby or blank the screen prior to calling VLC:

#!/bin/bash

#Disable modes
/usr/bin/xset -dpms &
/usr/bin/xset s off &

#Open VLC
/usr/bin/vlc "$@"

#Re-enable modes
/usr/bin/xset dpms
/usr/bin/xset s on
exit

Solution 2:

For me the solution was to access System Settings as root by pressing Alt+F2 to open the run dialog at the top of the screen and run

kdesudo systemsettings

then go to 'Display and Monitor' to get to the 'Screen Saver' selection screen and uncheck the checkbox next to 'Automatically start after:', then click 'Apply'. For some reason it seems that the screen saver setting is active on the root account in various versions of Kubuntu (probably in Ubuntu as well since I've seen posts for Ubuntu users experiencing this problem too). Doing this worked for me after first trying the suggested options of disabling Display Power Management and disabling the Screen Saver on my user account. I have not tested to see if the problem returns when those items are re-enabled but as I indicated with all of those items disabled I no longer have a problem with the screen going blank while watching videos with VLC.