Dtyjlui

in some sites when I watch a movie in a browser and I don't touch the computer the screen turns off. In other sites like Youtube I don't have that problem.
I tried using caffeine but I don't like the idea of having to manually enable and disable it every time I watch a video. I also tried other methods that I found on the internet but nothing worked.
any suggestions?
I'm using chrome and running ubuntu 16.04.

UPDATE 2017/08/23: Changed script to one that doesn't send keystrokes but disables dpms and the screensaver temporarily while a video is playing full screen.

This only works with applications running full screen, not maximized.

First install xdotool:

sudo apt install xdotool

then I created a scripts folder in my home folder that I could drop any scripts into that I wanted to keep:

mkdir -p ~/scripts

then I created a file called check_full.bsh in my ~/scripts folder and added the following content to it:

Since my screensaver is set for 20 minutes, I set the sleep timer in the script to 10 minutes (600 seconds). You can change this based on your screensaver settings.

#!/bin/bash



#Get DPMS settings

dpms_set=$(xset -q | grep -i "dpms is" | awk '{print $NF}')



#Get screensaver type and command

scrnsvr=$(ps -ef | grep screensav | grep -v grep | awk '{print $8}')

scrnsvrcmd=$(ps -ef | grep screensav | grep -v grep | awk '{print substr($0,index($0,$8))}')



#Sleep Timer in seconds.

SL=600



while true;

do

result=()

#Get all window geometries

all=($(xdotool search --name - | while read win; do xdotool getwindowgeometry $win | grep Geometry | awk '{print $2}'; done))



#Get all screen resolutions detected and build array.

SCREENS=($(xrandr | grep * | awk '{print $1}'))



SCRN=" ${SCREENS[*]} "



#Get result of all windows and match



for item in ${all[@]}; do if [[ $SCRN =~ " $item " ]] ; then result+=($item); fi; done



#If a result exists disable power management and screensaver

if [[ ${result[@]} ]]; then

    ps -ef | grep $scrnsvr | grep -v grep >/dev/null

    if [[ $? == 0 ]]; then 

    kill $(ps -ef | grep $scrnsvr | grep -v grep | awk '{print $2}')

    fi

    if [[ $dpms_set == "Enabled" ]];then

    xset -dpms

    fi

else    

    ps -ef | grep $scrnsvr | grep -v grep >/dev/null

    if [[ $? == 1 ]]; then

    ${scrnsvrcmd} &

    fi

    if [[ $dpms_set != "Disabled" ]];then

        xset dpms

        fi

fi

result=()

sleep $SL

done

make the script executable:

chmod +x ~/scripts/check_full.bsh

For some reason, a cron job would not run this correctly. So I added an entry to my startup to call this script. In the ~/.config/autostart/ folder, I created a file called Check_Full.desktop with the following content:

I like to have delays added to startup as they usually load better.

[Desktop Entry]

Type=Application

Name=Check_Full

Comment=Prevent screensaver from activating when full screen video is playing

Exec=bash -c 'sleep 5 && /home/<username>/scripts/check_full.bsh'

change above Exec line to match your home folder.

Set proper permissions to the file:

chmod 664 ~/.config/autostart/Check_full.desktop

After logging out and back in, check_full.bsh is now running and checking every 10 minutes if active application is full screen. If not, screensaver / lock screen launch at normal times.

Hope this helps!

Youtube doesn't have that problem because it uses HTML5 player. The sites you're having the problem with are using Flash Player instead. It is a bug in Adobe Flashplayer, which, in short, is that it never notifies WM that it ran into fullscreen. You may have heard though that Adobe Flash is a buggy app in general, so one workaround is to disable it, and use only sites with HTML5 video.

As you mentioned caffeine, you probably have searched for a solution already. Another thing you could do is to disable «power saving» completely, i.e. to force the screen to never turn off.