Hi,
We have had a number of calls about embedded videos in Moodle not displaying. The usual reason for this is due to how browsers handle mixed content.
The latest versions of browsers block insecure content that appears in secure pages. In this case the videos are insecure content appearing on Moodle which is a secure site. Unfortunately the browsers often do this silently without alerting the user. Here are instructions for Firefox and Chrome on how to display mixed content on a page:
Firefox:
http://support.mozilla.org/en-US/kb/how-does-content-isnt-secure-affect-my-safety
Chrome:
https://support.google.com/chrome/answer/1342714?hl=en
IE usually displays a pop-up asking users if they want to display insecure content:
http://support.microsoft.com/kb/2625928
Wesley