"Add Media Element"

1.  I've added two mp4 files to a page and the directory via the utility and deselected the auto-load, auto-play and download permission options.  The 53MB file will play both audio and video just fine.  PROBLEM to be resolved is this:  The 83MB file plays audio but does NOT display the video.  I've verified the file plays on other players (iTunes, windows media player...).  I've deleted it, reinstalled it, rebooted, created another page and tried again.....  What could be the issue, and how can I resolve it?

2.  The "help" associated with the "Add Media Element" says the viewing person needs to have a viewer installed on their computer to see these videos.  I thought the purpose of this was to have anyone be able to see the video in the embedded view on my webpage.  Pls explain.