Richard Stallman announced in September 1983 the plan to develop a free software Unix-like operating system called GNU. GNU is the only operating system developed specifically for the sake of users' freedom.
Guide to Formats
Audio FormatWe distribute our audio files in Ogg Vorbis format. We avoid MP3, because it is impeded by software patents in some countries. The Ogg Vorbis format is technologically superior to MP3, and is not encumbered by patents. The sound quality of speech recordings on this page is not indicative of the quality you could expect from Ogg Vorbis when applied to HiFi audio. Please avoid transcoding HiFi audio from MP3 to Ogg Vorbis. By doing so, you will create Ogg Vorbis files of a lower sound quality than the original MP3. Instead, please encode to Ogg Vorbis directly from the uncompressed source.
Vorbis.com provides a list of audio software and hardware (such as portable players) which support the ogg vorbis format. The Ogg Vorbis project is part of the Xiph.org project, where you will find the project development page and source code..
The ogg vorbis files available here have been made using an encoder released in March 2001. This encoder probably provides inferior sound quality to the latest codec, but does provide compatability both with very old and new decoders. If you have any trouble playing an ogg file, please ensure your player/ plugin/ library is a release of April 2001 or later.
Video FormatWe distribute our video files encoded with the Theora video codec, encapsulated in an ogg transport layer. Both our video and audio files therefore share the .ogg file extension.
The Theora video codec has been designed as a free video codec unencumbered by patent licensing restrictions. The technical brilliance and superb compression rates of the Theora codec should not be allowed to overshadow it's most important asset: it respects users' freedom! Many recent GNU/Linux distributions already provide support for playing theora video. Visit Theora for more information or to download players and codecs.
We use WebM instead of Theora for some videos; WebM is another more recent format, also unencumbered by known softare patents.