Loading WordPress 3.6 HTML5 video dynamically fails on IE (Invalid Source)

Hi there,

I’m doing a possibly-clever thing where I load an Amazon AWS-hosted video using WordPress 3.6’s HTML5 [video] shortcode dynamically using AJAX.

Basically the AJAX call will do:

echo apply_filters('the_content', '[video src="https://some.url.com/path.mp4" width="220"]');
die();

This works fine in Chrome, Safari on iOS and Firefox, but in IE (10 and 9) gives me an “Invalid source” error.

I’m wondering if there’s some javascript I have to load in order to make the video play in IE that’s not being loaded because I’m pulling the video in using AJAX?

Can anyone suggest what I might need to do?

Thanks

Ross