Zencoder
Zencoder is the creator of an open-source HTML5 video player, Video.js, built with Javascript, HTML, and CSS. Video.js plays video via native playback in all HTML5 browsers and devices, or through Adobe Flash when HTML5 playback is not available.
HTML5 Shiv
Prior to version 9 of Internet Explorer there was little or no support for HTML5 elements and other HTML5 features.