but used something like this in the past to achieve the effect of disabling suspend during playback of video via mpv

https://git.sr.ht/~anteater/mpv-inhibit-suspend

it is not for disabling screensaver, but could have the same effect. now on kde there it can be effected easily in tray, just activate @presentation mode<
similarly, on mate, i use sometimes @caffeine to inhibit sleep bevaviour.

When I use the XFCE-screensaver and a video is playing using mplayer or mpv or even within firefox (for example a youtube video) the screensaver does not activate while the video is playing, and this is the desired behaviour.

If I disable the XFCE-screensaver and instead use Xscreensaver from the Devuan repo, the screensaver kicks in at the configured idle time even when a video is playing so basically it ignores the communication from mplayer/mpv/firefox to prevent it from kicking in.

The man-page of Xscreensaver says:

xscreensaver-systemd is being started automatically by xscreensaver and I have elogind-daemon running (although I cannot tell whether it's able to connect to the D-Bus).

So to me it looks like it should work but maybe the Devuan elogind is not passing on the dbus messages or is somehow interfering in the process?

Has anyone succeeded in using Xscreensaver on Devuan with the screensaver not kicking in while videos are playing?