From Hydrogenaudio Knowledgebase
Ogg is a multimedia container format, and the native file and stream format developed by Xiph.Org, for their multimedia codecs. It an open format free for anyone to use. It is usually used to store Vorbis audio (or, less commonly, Theora video), and because of this, "Ogg" has been used incorrectly to refer to Vorbis.
For more details, see Xiph's explanation of the Ogg container.
See also Ogg entry in Wikipedia.
- encapsulation and interleave of multiple data streams,
- packet framing
- error detection
All in a small, bounded percentage bitrate overhead.
Ogg format specification is now published within the IETF in the following RFCs: