Theora video compression
Theora is a free and open video compression format from the Xiph.org Foundation. Like all our multimedia technology it can be used to distribute film and video online and on disc without the licensing and royalty fees or vendor lock-in associated with other formats.
Theora scales from postage stamp to HD resolution, and is considered particularly competitive at low bitrates. It is in the same class as MPEG-4/DiVX, and like the Vorbis audio codec it has lots of room for improvement as encoder technology develops.
Theora is in full public release as of November 3, 2008. The bitstream format for Theora I was frozen Thursday, 2004 July 1. All bitstreams encoded since that date will remain compatible with future releases.