HTML5 Video not working in IE 11

What is the resolution of the video? I had a similar problem with IE11 in Win7. The Microsoft H.264 decoder supports only 1920x1088 pixels in Windows 7. See my story: http://lars.st0ne.at/blog/html5+video+in+IE11+-+size+does+matter

I've been having similar issues of a video not playing in IE11 on Windows 8.1. What I didn't realize was that I was running an N version of Windows, meaning no media features were installed. After installing the Media Feature Pack for N and KN versions of Windows 8.1 and rebooting my PC it was working fine.

As a side-note, the video worked fine in Chrome, Firefox, etc, since those browsers properly fell back to the webm file.

I believe IE requires the H.264 or MPEG-4 codec, which it seems like you don't specify/include. You can always check for browser support by using HTML5Please and Can I use.... Both sites usually have very up-to-date information about support, polyfills, and advice on how to take advantage of new technology.