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 video
Mozilla and Opera support only the open formats of Theora and WebM. Google stated its intention to remove support for H.264 in 2011, specifically for the HTML5 video tag. Although it has been removed from Chromium, it has yet to be removed from Google Chrome five years later.