I know this is old, but here is a additional thing if you still encounter problems with the solution above.
Just put in your <head>
:
<meta http-equiv="X-UA-Compatible" content="IE=edge">
It will prevent IE to jump back to IE9 compatibility, thus breaking the video function. Worked for me, so if you still have problems, consider checking this out.
Alternatively you can add this in PHP :
header('x-ua-compatible: ie=edge');
Or in a .htaccess file:
header set X-UA-Compatible "IE=Edge"