HTML5 video codec support

Question

What codecs will be supported with the HTML5 video tag?

Will it vary by browser, or is there a spec of specific codec that will be supported?

Answer 1

It looks like IE9 supports WebM as Well as H.264

http://www.eweek.com/c/a/Application-Development/Microsoft-Updates-IE9-HTML5-Video-with-WebM-Support-213252/

And it looks like Microsoft is also providing a plugin for Chrome to support H.264