Ogg

File Format
Name	Ogg
Ontology	Electronic File Formats Audio and Music Ogg
Extension(s)	.ogg, .ogx, .ogv, .oga, .spx, .ogm, .opus
MIME Type(s)	application/ogg audio/ogg video/ogg
Released	1993

Ogg is a multimedia container format, most commonly used with Vorbis and other codecs developed by the Xiph.Org Foundation. Ogg files start with the magic number "OggS".

Although the initial specification and IANA registration called for the .ogg extension and application/ogg MIME type, regardless of the type of media in the container, the September 2008 RFC 5334 changed that recommendation and registered audio/ogg and video/ogg MIME types with corresponding .oga and .ogv extensions for content that is primarily audio or video respectively. The .ogx extension was introduced for use with content that incorporated the Ogg Skeleton and for which application/ogg remained appropriate. The .ogg extension was grandfathered to refer to Ogg audio with a Vorbis audio encoding. The .spx extension should be used for an Ogg audio file using the Speex codec.

Because Ogg formats are free and open-source, not proprietary as many other formats are, they are preferred by many "free-media" projects including Wikipedia, but this causes some issues for people attempting to view/listen to them, since some devices (e.g., Apple's iOS devices) don't support the Ogg formats, and others (e.g., Windows PCs) don't have "out-of-the-box" support until you install codecs, plug-ins, or software for it. Some of the proprietary formats have wider support in consumer devices in their default configurations.

Streams that can be placed in Ogg

• Audio
  • Speex
  • Vorbis
  • FLAC
• Video
  • Dirac
  • Theora
• Other
  • Kate

Software

• Konvertor
• Windows Media Player codecs for some Ogg formats
• Ogg QuickTime components (OSX, Windows)
• Miro Video Converter (watch out for attempts to install annoying toolbars in installer, as is regretfully common these days)

Utilities

• Online audio format converter

References

• Ogg documentation from xiph.org
• xiph.org wiki page for Ogg
• RFC 3533: The Ogg Encapsulation Format Version 0
• RFC 5334: Ogg Media types Redefines application/ogg and registers video/ogg and audio/ogg.
• Wikipedia: Ogg
• Ogg File Format, from Library of Congress resource on Sustainability of Digital Formats
• Ogg objections and Chris Montgomery's response