YouTube is introducing an experimental version of HTML 5 supported video player on YouTube. HTML5 is a new web standard that is gaining popularity rapidly and adds many new features to your web experience. Most notably for YouTube users, HTML5 includes support for video and audio playback. This means that users with an HTML5 compatible browser, and support for the proper audio and video codec’s can watch a video without needing to download a browser plugin. HTML 5 supported video player does not support videos with ads and full screen support.
As of now HTML 5 supported video player work only with Google Chrome ,Apple Safari (version 4+) and Microsoft Internet Explorer with Chrome Frame installed. It won’t work in Firefox,Even though Firefox supports HTML <video> feature but it does not support H.264 Codec. Even in the browsers that do support it, the HTML5 player is a pale copy of the Flash-based one. A lot of features are missing and some things aren’t as smooth as you’d expect.
Kevin Carle, a software engineer at YouTube Wrote,
To try it out, go to the HTML5 page via TestTube or visit this page and join the experiment. This will enable HTML5 video for your browser, provided that it’s one of the browsers mentioned above and fits in with the parameters we already referenced. (If you’ve opted in to other experiments, you may not get the HTML5 player.) You can also enable Feather watch (visit http://www.youtube.com/feather_beta) along with HTML5 video for an even simpler, faster YouTube experience.