Because Power Screensaver Builder use the Windows Media Control Interface driver to play video movies in screensavers , what codecs are supported by PSSB is depend on What codecs have been installed to your Windows system . That is to say , if you had installed a MPEG-4 codec on your system , you can add a MPEG-4 video movie to your screensaver. Use the Windows Media Control Interface driver to play video movies can reduce the size of output file and can use all codecs on your system.
To check what codecs have been installed on your system , you can click "Start" ---->"Setting"----->"Control panel" -----> "Audio & Multimedia"---->"Device", select the "Video codecs" and click the property button. (These steps may have some difference in different Windows operating system.)