From Fedora Project Wiki
Thusnelda
In support of Free Culture, the open web and to reduce the hold of proprietary and patent encumbered codecs, Red Hat has been sponsoring improvements on the open Ogg Theora video codec implementation codenamed Thusnelda via Christopher Montgomery (xiphmont), who created the format and work has resulted in drastic improvements to the codec. This release features this next generation codec. All applications using libtheora library including all the Gstreamer applications will automatically and transparently be taking advantage of the improvements.