Using HTML5 I am trying to get the attribute (ie rotation), located in the header of a mp4 (I play it using a video tag), to do this I am trying to get the bytes that make up th
I do not think you can extract such detailed metadata from a video, using HTML5 and its video-tag. The only things you can extract (video length, video tracks, etc.) are listed here:
http://www.w3schools.com/tags/ref_av_dom.asp
Of course, there might be special additional methods available in some browsers, but there is no "general" approach - you would need more than the existing methods of HTML5.