I tried the NextPVR "CutOut" screensaver but that runs NextPVR.exe at 38% processor on my HP Microserver!! It also seems to make the blank screens much more frequent but does seem to refresh the screen after several seconds. The processor continued to run at around 38% when the client was playing a recording and the NPVR screen saver was not showing on the server screen.
I tried the "FixedImage screensaver which uses very little processor power but that only moves every 7 seconds so less efective refreshing the screen.
I think I may disable the screen saver and accept occasional blank screens as the lesser evil!!
NextPVR Server - HP N54L Microserver, Windows 7 - Storage 2 X 3TB in Windows mirror- Tuners DVBSky S952 Twin DVB-S/S2 PCIe, August T210 DVB-T/T2 USB, KWorkd UB499-2T Twin DVB-T USB.
Clients RPi2 & Acer RL80 Celeron Nettop both running X-NEWA on LibreElec.