WebM video files play directly in your web browser using a new technology called HTML5. No plug-ins are required, but you must install a web browser that supports WebM files. See the instructions below in “How to Play WebM Videos.”
Go to www.youtube.com/html5 and enroll in the YouTube HTML5 experiment. Note that this sets a cookie with a relatively short expiration, so you may need to re-enroll in the future.
Download and install a supported browser (listed below). For the most popular videos on YouTube, Google Chrome users will be served the WebM format by default.
To explicitly request WebM-format videos, perform the following additional steps:
Search for a video by keyword. For example, trailers.
When your search results are returned, add &webm=1 to the end of the URL and hit Enter to resubmit. The results returned by this modified search will favor WebM results even if you’re not using Chrome.
For Windows Media Player 12 on Windows 7, install the WebM Media Foundation Components. Though the components refer to Internet Explorer 9, installing them will add system-wide WebM support in applications that use Media Foundation.
For earlier versions of Windows Media Player, follow the instructions for installing the WebM DirectShow filters. As indicated, be sure to also install the Vorbis audio filters.
Ask and answer questions on the webm-discuss list.