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Ogg

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For help with sound or video, see Wikipedia:Media help. For other meanings of this acronym, please see OGG (disambiguation)

Ogg is a patent-free, fully open multimedia bitstream container format designed for efficient streaming and file compression (storage).

The name "Ogg" hence refers to the file format which includes a number of separate independent open source codecs for both audio and video. Files ending in the .ogg extension may be of any Ogg media filetype, and because the format is free, Ogg's various codecs have been incorporated into a number of different free and commercial media players.

The term "Ogg" sometimes incorrectly refers to the Vorbis audio codec. Other prominent components of Ogg are its video codec Theora, and the human speech audio compression format, Speex.

File format

The Ogg bitstream format, spearheaded by the Xiph.org Foundation, has been created as the framework of a larger initiative aimed at developing a set of components for the coding and decoding of multimedia content which are both freely available and freely re-implementable in software.

The format consists of chunks of data each called an Ogg Page. Each page begins with the "OggS" string which can be used to identify the file as Ogg.

A serial number and page number in the page header identifies each page as part of a series of pages which make up a bitstream. Multiple bitstreams may be muxed in the file where pages from each bitstream are ordered by the seek time of the contained data. Bitstreams may also be appended to existing files, a process known as chaining, to cause the bitstreams to be decoded in sequence.

Ogg Stream Example
Ogg Stream Example

A BSD-licensed library, called libogg, is available to encode and decode data from Ogg streams. Independent Ogg implementations are used in several projects such as RealPlayer and a set of DirectShow filters.

History

It is often assumed that the name Ogg comes from the character of Nanny Ogg in Terry Pratchett's Discworld novels. Rather, it is jargon that arose in the computer game Netrek, originally meaning a kamikaze attack, and later, more generally, to do something forcefully, possibly without consideration of the drain on future resources. At its inception, the Ogg project was thought to be somewhat ambitious given the power of the PC hardware of the time.

The Ogg bitstream is defined in RFC 3533 and its MIME media type (application/ogg) in RFC 3534. The current Ogg version, released on September 23, 2004, is 1.1.2.

Ogg codecs

  • Audio codecs
    • lossy
      • Speex: handles voice data at low bitrates (~8-32 kbit/s/channel)
      • Vorbis: handles general audio data at mid- to high-level bitrates (~16-256 kbit/s/channel)
    • lossless
      • FLAC: handles archival and high fidelity audio data

Ogg clients

Patent-free open source alternatives

Proprietary alternatives

Various components of the project are intended to stand as alternatives to proprietary codecs such as:

Ogg compatible hardware players

  • Cowon iAudio 5 - 256mb to 2gb flashdrive
  • Cowon iAudio G3 - 256mb to 1gb flashdrive
  • Cowon iAudio M3 - 20gb to 40gb harddrive
  • Cowon iAudio M5 - 20gb harddrive
  • Cowon iAudio U2 - 256mb to 1gb flashdrive
  • Cowon iAudio X5 - 20gb to 60gb harddrive
  • iRiver H100 series - 20gb to 40gb harddrive
  • iRiver H300 series - 20gb to 40gb harddrive
  • iRiver iFP-700 Series - 128mb to 1gb flashdrive
  • iRiver iFP-800 Series - 128mb to 1gb flashdrive
  • iRiver iFP-900 Series - 256mb to 1gb flashdrive
  • IOPS Z5 - 512mb to 1gb flashdrive
  • Mpio ONE - 256mb to 1gb flashdrive
  • Mpio hd 200 - 5gb harddrive
  • Mpio hd 300 - 20gb to 40gb harddrive
  • Neuros jukebox - 256mb to 20gb flashdrive/harddrive
  • Neuros II - 256mb to 60gb flashdrive/harddrive
  • RioVolt SP250 (but you'll need to install the iriver firmware) - CD
  • Rio Karma - 20gb harddrive
  • Samsung YP-C1 - 256mb to 1gb flashdrive
  • Samsung YP-MT6 - 256mb to 1gb flashdrive
  • Samsung YP-T6 - 256mb to 1gb flashdrive
  • Samsung YP-T7 - 256mb to 1gb flashdrive
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