You do not mention the platform or FMP ver - but I would guess Mac and FMP 12?
Filemaker is using Quicktime Player for displaying the video, unless you have set VLC or other to handle video files by default?
Play Quicktime Movie Full Screen
Play Quicktime Movie Full Screen April 17, 2012
SuperContainer is a FMP Plugin that offers more options and better performance over FMP native containers including
Files stored in SuperContainer are interactive - you can click on them to see a full-sized image, the contents of a Word or PDF file, or play a QuickTime movie. You can also optionally add a button with an 'Open URL' script step to open your SuperContainer files in a full-screen view.
Thanks for the help.