Safari Videos
Videos won't start in Safari
Mac Pro, iOS 6.0.2
1. Install Adobe Flash Player.
http://get.adobe.com/flashplayer/
2 .Are Plug-ins Enabled?
Enable Plug-ins
Safari > Preferences > Security
Web Content:
Click in the box for "Enable Plug-ins".
3. Check whether you are currently in YouTube HTML 5 trial.
At the bottom left of the page uncheck the box for
"You are currently in the HTML5 trial".
4. Reset Safari.
Click Safari in the menu bar.
From the drop down select "Reset Safari".
Uncheck the boxes next to:
Remove saved names and passwords
Remove other AutoFill from text.
Click "Reset".
5. Turn off Extensions.
Safari > Preferences > Extensions
Hopfuly one of these steps may help.