PowerPoint-videos flash previous slide when changing slides

Hi,

At first I have to say: finally, finally I found this beast called Xibo. Thanks!
Even I’m happy with it, I got in trouble with PowerPoint videos.

So, I exported a PowerPoint-presentation to .mp4 and put it on a layout. All my seven players plays it, but every time a slide changes, player flashes the previous slide for a second until comes back to new slide.
For a clarification: a new slide appears, then a previous one flashes and then the new one shows until time’s up.

Video itself seems to run perfectly on windows media player on these player computers.

Any ideas why it is working this way for me?
We are in windows environment. Server runs on xampp and all players on windows machines.

I have the same problem…