Well thanks for advice.
I already have Prism. I tried to play mpeg4 file from Prism - "unable to play". File as such can be played normaly on VLC or QuickTime.
If it's change something, that camera is Rollei (Germany) :-).
So you sugest to convert mpeg4 to avi. But how about quality. It will be the same? I'm afraid not.
But I will try all sugestions what was here.