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Vorbis was started following a September 1998 letter from Fraunhofer Gesellschaft announcing plans to charge licensing fees for the MP3 format. Soon after founder Christopher Montgomery began work on the project, he was assisted by a growing collection of other developers. They continued refining the code until a stable version 1.0 of the codec was released on July 19, 2002.
The latest version is 1.1.0 released on 2004-09-22 . Source code for this release is available from the official Vorbis web site, while many Windows binaries can be downloaded at Rarewares.
The Ogg Vorbis format has proved popular among open source communities; they argue that its higher fidelity and completely free nature make it a natural replacement for the entrenched MP3 format. However, MP3 has a popular history dating back to the mid- 1990s and as of 2004 is still the primary lossy audio format. It may be some time before one sees more Ogg format files than MP3 files. In the commercial sector, Vorbis has already had success with many newer video game titles employing Vorbis as opposed to MP3. The increasing number of hardware players that support Vorbis is encouraging its growth as of July 2004; see the compatible hardware below.
Given 44.1 kHz (standard CDCD re-directs here; see Cd for other meanings of CD . A compact disc (or CD is an optical disc used for storing digital data. It was originally invented for digital audio and is also used as a data storage device, a CD-ROM. CD-ROM reading devices are a st audio sample frequency) stereo input, the current encoder as of July 2004 will produce output from 45 to 500 kbit/s depending on the specified quality setting. Though Vorbis 1.0.1 is tuned for bitrates of 16 to 128 kbit/s/channel, it is still possible to encode arbitrary bitrates chosen by the user. Such figures are only approximate, however, as Vorbis is inherently variable-bitrate ( VBR).
Vorbis uses the modified discrete cosine transformThe modified discrete cosine transform (MDCT is a Fourier-related transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped it is designed to be performed on consecutive blocks of a larger dataset, whe (MDCT) for converting sound data from the time domain to the frequency domain. The resulting frequency-domain data is broken into noise floor and residue components, and then quantized and entropy coded using a codebook-based vector quantization algorithm. The decompression algorithm reverses these stages.
Vorbis's specifications are in the public domain (Xiph.org reserves the right to set the Vorbis specification and certify compliance). Its libraries are released under a BSD-style license and its tools are released under the GPL (GNU General Public License).
The Xiph.org Foundation says that Vorbis, like all its developments, is completely free from the licensing or patent issues raised by other proprietary formats such as MP3. Although Xiph claims to have conducted a limited patent search that supports its claims, outside parties have expressed doubt that Vorbis is free of patented technology. Xiph says that it was issued a legal opinion privately subject to attorney/client privilege, and has not released an official statement on the patent status of Vorbis. No conclusive evidence has been presented that Vorbis is or is not patent-free as of 2004. Some Vorbis proponents have derided the uncertainty concerning the patent status as " FUD": disinformation spread by large companies with a vested interest.
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