Tremor (software)

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Tremor by the Xiph.Org Foundation is a fixed-point version of the Vorbis decoder for those platforms without floating point operations.

Xiph.Org Foundation is a non-profit organization that produces free multimedia formats and software tools. It focuses on the Ogg family of formats, and the most successful one has been Vorbis, an open and freely licensed audio format and codec designed to compete with the patented WMA, MP3 and AAC. As of 2013, the current development work is focusing on Daala, an open and patent-free video format and codec designed to compete with VP9 and the patented High Efficiency Video Coding.

In computing, a fixed-point number representation is a real data type for a number that has a fixed number of digits after the radix point. Fixed-point number representation can be compared to the more complicated floating-point number representation.

Vorbis is a free and open-source software project headed by the Xiph.Org Foundation. The project produces an audio coding format and software reference encoder/decoder (codec) for lossy audio compression. Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis.

It is a software library that decodes the Vorbis audio format. It is free software released under the New BSD license. Tremor uses fixed-point and movable-point arithmetic numeric representations in its implementation so that it can be used by small embedded devices, which typically do not have floating-point processors. Thus, Tremor enables small embedded devices to play audio files stored in the Vorbis format. Tremor was originally developed by Xiph.Org as a part of a contract for the Iomega HipZip,[ citation needed ] but was since opened up to encourage wider use of the Vorbis format. Almost all hardware devices[ clarification needed ] that can play Vorbis, and many software implementations on embedded devices (such as mobile phones) use Tremor or some descendant.

Free software software licensed to preserve user freedoms

Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price: users—individually or in cooperation with computer programmers—are free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed free insofar as they give users ultimate control over the first, thereby allowing them to control what their devices are programmed to do.

Xiph.Org has expressed interest in modifying Tremor into a floating-point version, which would replace the current floating-point reference decoder, after the release of libogg2. [1]

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Ogg digital container format

Ogg is a free, open container format maintained by the Xiph.Org Foundation. The creators of the Ogg format state that it is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high-quality digital multimedia. Its name is derived from "ogging", jargon from the computer game Netrek.

Windows Media Audio (WMA) is a series of audio codecs and their corresponding audio coding formats developed by Microsoft. It is a proprietary technology that forms part of the Windows Media framework. WMA consists of four distinct codecs. The original WMA codec, known simply as WMA, was conceived as a competitor to the popular MP3 and RealAudio codecs. WMA Pro, a newer and more advanced codec, supports multichannel and high resolution audio. A lossless codec, WMA Lossless, compresses audio data without loss of audio fidelity. WMA Voice, targeted at voice content, applies compression using a range of low bit rates. Microsoft has also developed a digital container format called Advanced Systems Format to store audio encoded by WMA.

Speex is an audio compression format specifically tuned for the reproduction of human speech and also a free software speech codec that may be used on VoIP applications and podcasts. It is based on the CELP speech coding algorithm. Speex claims to be free of any patent restrictions and is licensed under the revised (3-clause) BSD license. It may be used with the Ogg container format or directly transmitted over UDP/RTP. It may also be used with the FLV container format.

FLAC reference software for the handling of FLAC data

FLAC is an audio coding format for lossless compression of digital audio, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompress to an identical copy of the original audio data.

Theora is a free lossy video compression format. It is developed by the Xiph.Org Foundation and distributed without licensing fees alongside their other free and open media projects, including the Vorbis audio format and the Ogg container.

Monkey's Audio is an algorithm and file format for lossless audio data compression. Lossless data compression does not discard data during the process of encoding, unlike lossy compression methods such as AAC, MP3, Vorbis and Musepack.

On2 TrueMotion VP3 is a (royalty-free) lossy video compression format and video codec. It is an incarnation of the TrueMotion video codec, a series of video codecs developed by On2 Technologies.

Icecast Multimedia streaming server

Icecast is a streaming media project released as free software maintained by the Xiph.org Foundation. It also refers specifically to the server program which is part of the project. Icecast was created in December 1998/January 1999 by Jack Moffitt and Barath Raghavan to provide an open-source audio streaming server that anyone could modify, use, and tinker with. Version 2, a ground-up rewrite aimed at multi-format support and scalability, was started in 2001 and released in January 2004.

WavPack is a free and open-source lossless audio compression format.

This table compares features of container formats. To see which multimedia players support which container format, look at comparison of media players.

OggSquish was one of the first names used for the Ogg project developed from 1994 by the Xiphophorus company. Ogg Squish was also an attempt from the Xiphophorus company to create a royalty-free lossless audio compression codec.

Cortado is a streaming Java applet for Ogg formats Vorbis, Theora and Kate, µ-law, MJPEG and Smoke, released under the GPL. With Cortado a webpage can be set up to download the applet on the fly in the background, providing embedded support for Ogg-based media in Java-enabled web browsers without the need to install further software. Among others it is used on Wikimedia projects and blip.tv.

VP8 an open, royalty-free lossy video coding format released by Google in 2010

VP8 is an open and royalty free video compression format owned by Google and created by On2 Technologies as a successor to VP7.

Constrained Energy Lapped Transform (CELT) is an open, royalty-free lossy audio compression format and a free software codec with especially low algorithmic delay for use in low-latency audio communication. The algorithms are openly documented and may be used free of software patent restrictions. Development of the format was maintained by the Xiph.Org Foundation and later coordinated by the Opus working group of the Internet Engineering Task Force (IETF).

The HTML5 draft specification adds video and audio elements for embedding video and audio in HTML documents. The specification had formerly recommended support for playback of Theora video and Vorbis audio encapsulated in Ogg containers to provide for easier distribution of audio and video over the internet by using open standards, but the recommendation was soon after dropped.

Opus (audio format) audio compression format

Opus is a lossy audio coding format developed by the Xiph.Org Foundation and standardized by the Internet Engineering Task Force, designed to efficiently code speech and general audio in a single format, while remaining low-latency enough for real-time interactive communication and low-complexity enough for low-end embedded processors. Opus replaces both Vorbis and Speex for new applications, and several blind listening tests have ranked it higher-quality than any other standard audio format at any given bitrate until transparency is reached, including MP3, AAC, and HE-AAC.

References

  1. ↑ "Xiph.Org Monthly Meeting log for October 2006".
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