Vorbis

Vorbis is a free, lossy general digital audio codec, developed by the Xiph.Org Foundation, that uses the Ogg container or audio file format.

Overview

Ogg Vorbis is part of the Ogg project and was called Ogg Vorbis or just ogg because it is the codec most commonly found in the Ogg container.

Vorbis is a general-purpose perceptual audio codec intended to allow maximum encoder flexibility, allowing it to scale competitively over an exceptionally wide range of bitrates.

Even though the lossy compression algorithm produces a smaller amount of information, it is an encoding procedure that aims to eliminate a certain amount of information considered irrelevant to reduce the volume of data. This idea was previously used for example in mp3 compression.

On the quality level/bitrate scale (CD audio or stereo DAT-rate, 16/24 bits) it is in the same league as MPEG-2 and Musepack (MPC) and comparable with AAC at most bitrates. Similarly, the 1.0 encoder can encode quality levels from CD audio and DAT-rate stereo up to 48kbps without lowering the sample rate. Vorbis is also intended for low sample rates from 8kHz telephony and up to 192kHz HD, and a range of channel representations (monaural, polyphonic, stereo, quadraphonic, 5.1, ambisonic or up to 255 discrete channels).

Ogg Vorbis is completely open, patent and royalty-free; The reference library (libVorbis) is distributed under a BSD-type license so anyone can implement it for both proprietary and free applications. Audio streaming applications such as Spotify use the Ogg format (quality -q9, see table below) in a premium version.

History

Vorbis is the first codec developed as part of the multimedia projects of the Xiph.Org Foundation. It started immediately after Fraunhofer IIS (creators of MP3) sent an "infringement letter" to several small projects developing MPEG Audio Layer 3, mentioning that due to the patents they hold on MP3 they have the right to charge royalties for any commercial player., all encoders (whether sold or free) and also artwork sold in MP3 format. For this reason, the Ogg Vorbis and the Xiph.Org Foundation were created to protect multimedia content on the Internet from the control of private interests.

The bitstream format for Vorbis I was frozen on May 8, 2000; all files created since that date will continue to be compatible with future Vorbis releases.

Version 1.0 was announced in July 2002, with an "Ogg-Vorbis 1.0 Announcement Letter" thanking the support received and explaining why the development of free codecs is necessary.

Vorbis is named after a character in the book Minor Gods by Terry Pratchett.

Features

Technical details

Vorbis uses the Modified Discrete Cosine Transform (MDCT).