The WebM Project

http://www.webmproject.org/

WebM is an audio-video format designed to provide a royalty-free, open video compression format for use with HTML5 video. The project's development is sponsored by Google.
A WebM file consists of VP8 video and Vorbis audio streams, in a container based on a profile of Matroska.

The project releases WebM related software under a BSD license and all users are granted a worldwide, non-exclusive, no-charge, royalty-free patent license. Despite this, some in the industry have called upon Google to provide indemnification against patent suits.

http://en.wikipedia.org/wiki/Webm

WebM is supported by Mozilla, Opera, Adobe, Google and more than seventy other publishers and software and hardware vendors.

Developers: Money For Nothing and the Codecs For Free

From SlashDot:

"In an in depth discussion on the codec industry, CoreCodec CEO and Matroska Foundation board member Dan Marlin shares his thoughts on the growing popularity of the MKV container, confusion in the marketplace between X.264/MKV and DivXHD and weighs in on a controversial decision by Microsoft to block third party filter support in future versions of Windows media player. His interview offers a behind the scenes look at an important piece of technology that is helping to power the P2P movement. It also raises the prickly question of whether or not Microsoft is abusing their OS monopoly, in order to rein in competition within the codec industry."