Use the C1VideoExtender control to play videos in HTML5. Note that not all browsers currently support HTML5. Make sure that you are using a browser that does in order to view the video.
C1VideoExtender Markup
The following markup creates the C1VideoExtender control. Set the TargetControlID property to attach the extender to a control.
<cc1:C1VideoExtender ID="Panel1_C1VideoExtender" runat="server"
TargetControlID="Panel1">
</cc1:C1VideoExtender>