Nice think about screensaver. It allways a problem it came across when you play a video.
You could otherwice simply disable the screensave while playing a video or checking if a video is in queue or not, so the screensaver is autodisbled until the video is played finish.
In My software, the screensaver (just cycle colors like many Atari 2600 games) can come across, but it disabled that, when a CDG is going to play and disable that until it played finisheded. That is what I did....