Introduction to the Ogg Vorbis format

Ogg Vorbis is an audio data compression format developed by Xiph.org.

As with the MP3 format, it's a form of compression which reduces some of the audio data, called "lossy compression". This means eliminating some of the audio data (non-audible frequencies, for example) in order to get the best compression rate possible, while producing an output file which sounds as close as possible to the original data.

What sets Ogg Vorbis apart is that it is an open-source format, unlike its main competitors, such as MP3, WMA, Atrac and AAC. This means that the compression algorithm may be used freely by all software developers, which has helped in developing and releasing numerous open-source tools and programs.

Technical characteristics

Ogg Vorbis uses variable bite-rare encoding (VBR for short), a method of encoding which modifies the number of bits used per second to encode sound data, depending on how complicated the audio stream is at a given moment. In other words, this means that the amount of data used to encode a certain portion of the audio won't be the same for silence as it is for a polyphonic choir.

While the MP3 format can only record on up to two channels (stereo), Ogg Vorbis can record polyphonically (several channels) and therefore can reproduce sound on systems using 4.5 (5.1) or 7 (7.1) channels.

As Ogg Vorbis is a more recent format than MP3 (version 1.0 of Ogg Vorbis came out on Monday, 8 May 2000), it provides better sound fidelity, in the frequency range of 8kHz-48.0kHz.

Finally, Ogg Vorbis files are usually smaller than MP3s.

The files below, provided courtesy Xiph.org, can be used to compare the quality of the various audio compression formats:

Compatibility

The Ogg Vorbis format is not compatible with the MP3 format, which means that a user must use an audio player which supports the format or install a specific codec in order to be able to play Ogg Vorbis files.

However, more and more sound programs are able to play Ogg Vorbis files, and most recent hardware MP3 players support the format.

More information

• Xiph Foundation
• Introduction to the Ogg Vorbis format
• Main page of vorbis.com
• FAQ for Ogg Vorbis
• Ogg Vorbis music samples
• Software compatible with Ogg Vorbis