Google tests (semi) HTML5 YouTube embed code
It works with HTML5. Except when it doesn't
Google is testing new YouTube embed code that plays videos using either the company's experimental HTML5 player or its standard Flash player, depending on the video and the setup of the user's system.
YouTube is still very much wedded  to its Flash player, but since January, Google has offered an experimental HTML5 player that operates sans plug-in. The player uses either the royalty-hampered H.264 codec or the newly open source WebM format, so it won't work with the stable version of Firefox (let alone Internet Explorer 8), and it doesn't handle YouTube ads.
But don't get your hopes up. The new embed code won't let you use the HTML5 player if a video has ads.
If you've set up your system to use the HTML5 player and the video doesn't have ads and it support Google's setup other ways, the embed code will player the video with HTML5. If not, it defaults to Flash.
Google unveiled the new code with a Thursday blog post , indicating it would soon be rolled out across the entire site. "Before we make this new embed code the standard for our general users, we wanted to give our developer community a preview," the post reads.
The new embed code – for embedding YouTube in third-party sites – uses the iframe HTML tag. It looks like this:
<iframe class="youtube-player" type="text/html" width="640" height="385" src="http://www.youtube.com/embed/VIDEO_ID" frameborder="0"></iframe>
"If you use the new embed code style, your viewers will be able to view your embedded video in one of our Flash or HTML5 players, depending on their viewing environment and preferences," Google says. "Environments that support the HTML5 video player are listed here on our HTML5 settings page . In instances where HTML5 isn't supported (e.g. our HTML5 player can't play videos with ads), we use Flash."
Google's HTML5 player works with test versions of Firefox that support the WebM format, Opera, Google Chrome, Apple Safari 4.0 or later, the Microsoft Internet Explorer 9 beta, and other version of IE if they're equipped with Google Chrome Frame, the plug-in that turns Microsoft's browser into a Google browser. But not all videos will work with the player. Google has only begun to encode videos with WebM, and even test versions of Opera and Firefox don't support H.264. Opera and Mozilla don't believe in royalty-hampered codecs.
Created by Google, WebM is an effort to provide a royalty-free codexc for use with HTML5. Opera and Mozilla have vowed to make the leap to WebM, based on the VP8 codec Google open sourced in May. And Microsoft will allow WebM use if IE9 surfers install the codec themselves. But Apple is still firmly behind H.264, a codec licensed by the patent pool organization known as MPEG-LA. Like Microsoft, Apple is a member of the H.264 patent pool.
In order to use the HTML5 player, you must join the beta program here 
Last month, with another blog post, Google confirmed that Flash will continue to "play a critical role " on Youtube because HTML5 isn't ready for prime time. One of the reasons Google gave is that HTML5 doesn't allow users to easily lift video from YouTube and embed it in other sites.
"Flash Player's ability to combine application code and resources into a secure, efficient package has been instrumental in allowing YouTube videos to be embedded in other web sites," the post read.
"Web site owners need to ensure that embedded content is not able to access private user information on the containing page, and we need to ensure that our video player logic travels with the video (for features like captions, annotations, and advertising). While HTML5 adds sandboxing and message-passing functionality, Flash is the only mechanism most web sites allow for embedded content from other sites."
It would seem that Google eventually wants to move away from Flash. But this isn't happening any time soon. ®