Hi Blake,
I viewed another support question raised a while ago that was similar to this where you suggested trying some test videos and a fall back image to see whether the problem was with the browser or the encoding of the video.
I downloaded these and tried it on my site and the issue still occurred. These videos were 5mb at the largest so I don’t think its solely down to the file sizes of my videos.
When I debug the page within IE, I am seeing an error related to an extra <body> tag, however, I cannot find the extra tag within the HTML.
Could this be the cause of the issue? If so, what can I do about it?