I’ve been working with Facebook’s Open Graph trying to share custom videos and just like every other Facebook technology there are a few caveats. The first being if you don’t have an image to go along with your video you won’t see the video player in your news feed. Second you have to make all of the OG links use https otherwise those users won’t see the player. Instead they will be taken to the page with all the OG data. Thirdly, you should set a video width and height meta tag that doesn't cause scrollbars. I've been using the same dimensions as YouTube, 398x224.