askcharlyleetham.com We were having problems with videos rendered with a m4v extension and hosted on Amazon S3 playing on Internet Explorer. The error message -The video could not be loaded, either because the server or network failed or because the format is not supported:- would be displayed. After a bit of investigation, we found the issue was related to the http headers being set when the videos were uploaded – changing the content type to the correct video type fixed the problem!
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Fixing HTML5 Video Issues In Internet Explorer