Vorbis

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Vorbis is a completely open and free audio compression (codec) project from the Xiph.org Foundation. It is frequently used in conjunction with the Ogg container and is then called Ogg Vorbis.

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.

Contents

1 Popularity growth

2 Technical details

3 Licensing

4 Hardware and software support

4.1 Hardware
4.2 Software

5 Trivia

6 See also

7 External links

Popularity growth

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.

Technical details

Given 44.1 kHz (standard CD 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 transform (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.

Licensing

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.

Hardware and software support

Tremor, a version of the Vorbis decoder which uses fixed-point arithmetic (rather than floating point) was made available to the public on September 2, 2002 (also under a BSD-style license). Tremor, or platform specific versions based on it, is more suited to implementation on the limited facilities available in commercial audio systems (such as portable players). A number of versions, which make adjustments for specific platforms, and which include customised optimisations for given embedded microprocessors, have been produced. Several hardware manufacturers have expressed an intention to produce Vorbis-compliant devices, and new Vorbis devices seem to be appearing at a steady rate, especially in South Korea, although availability might differ from country to country.

Hardware

The VorbisHardware node at the xiph.org wiki has an up-to-date list of Vorbis-supporting hardware, such as portables, PDAs, and microchips.
Here are a few examples of devices that play Ogg Vorbis files:

All iRiver harddisk players support Ogg Vorbis. Most of the flash-memory players will play Ogg Vorbis without a firmware upgrade.
The Neuros (site) portable player released a firmware upgrade offering Ogg Vorbis support after a beta testing period in the latter half of 2003. Firmware versions 1.45 and newer support Ogg Vorbis.
Rio Karma, an mp3 player supporting both Ogg Vorbis and FLAC.
The Jens of Sweden MP-130 (site) supports Ogg Vorbis.
The Xclef HD800 [1] supports Ogg Vorbis amongst other formats.
Cowon iAudio M3 [2]
Samsung YP-60V
KiSS DVD-Players (site) are supporting Ogg Vorbis, MP3 and WMA. Some models have an Ethernet port allowing to stream audio and video from a PC on the network or listen to Web radio.

Software

Ogg Vorbis (as of 2003) can be played using these (and other) players:

XMMS for Unix-like systems (GPL) [formerly known as X11amp]
MPlayer for Unix-like systems (GPL)
Rhythmbox for Unix-like systems, GNOME based and GPL
amaroK for Unix-like systems, KDE based and GPL
zinf for Linux and Windows (GPL) [formerly known as FreeAmp]
Winamp for Windows (freeware) [No further development expected]
JetAudio for Windows (freeware)
JOrbis pure Java (LGPL)
foobar2000 for Windows (freeware) focused on high quality playback
GStreamer for Unix-like systems (GPL)
VLC media player for Windows, Mac OS X, and Unix-like systems. (GPL)
PocketOgg for Pocket PC
Quintessential Player for Windows, MAC (freeware)
Sonique for Windows (freeware)
Pocket Tunes for PalmOS 5
AeroPlayer for PalmOS 5
Symbian OggPlay for Symbian OS (Series 60 as well as UIQ) based Smartphones
XMPlay for Windows (freeware)
dBpowerAMP for Windows
Vorbis can be played by Microsoft's Windows Media Player using an Ogg Vorbis DirectShow filter available at [3]; a different DirectShow filter is available at [4].
There is a QuickTime component available at the qtcomponents SourceForge project. This allows Vorbis audio to be played by the popular iTunes software.

In July 2002, RealNetworks announced that they will support Ogg Vorbis in their products. See Helix project for more details.

Trivia

"Ogg" is not named after the witch Nanny Ogg in Terry Pratchett's Discworld books. However, "Vorbis" is named after another Discworld character, High Priest Vorbis in Small Gods.

External links

ca:Ogg-Vorbis da:Ogg Vorbis de:Vorbis es:Ogg Vorbis fr:Ogg Vorbis it:Ogg Vorbis he:Ogg Vorbis hu:Vorbis nl:Ogg Vorbis ja:Ogg Vorbis pl:Vorbis pt:Vorbis ru:Ogg vorbis fi:Ogg Vorbis sv:Ogg Vorbis tr:Ogg Vorbis