Safari Lecture Video Issues
Safari 7.0 and 6.1 include a new feature called Safari Power Saver, which is intended to disable plug-ins in order to conserve battery power.
When hovering over the video window of a presentation, there should be an icon that appears which you can click on in order to allow the plug-in on that webpage. However, we have seen cases where this icon does not appear properly. If this happens, you must disable Power Saver completely in order to allow the plug-in to run.
To disable the Power Saver function, enter Safari Preferences
Then go to the Advanced tab, and uncheck the box to "Stop plug-ins to save power".
Reload the webpage containing the Mediasite presentation and it should play properly.