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.
Comparison of HTML5 and Flash
Because HTML5 is an open format, tools like those for Flash can be built for it, too. Applications like Hype and Adobe Edge are already on the market.