Ogg контейнері: ашық мультимедиа форматы

Open container format maintained by the Xiph. Org Foundation

Ogg is a free, open container format maintained by the Xiph. Org Foundation. The authors 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. The Ogg container format can multiplex a number of independent streams for audio, video, text (such as subtitles), and metadata. In the Ogg multimedia framework, Theora provides a lossy video layer. The audio layer is most commonly provided by the music oriented Vorbis format or its successor Opus. Lossless audio compression formats include FLAC, and OggPCM. Before 2007, the ogg filename extension was used for all files whose content used the Ogg container format. Since 2007, the Xiph. Org Foundation recommends that ogg only be used for Ogg Vorbis audio files. The Xiph. Org Foundation decided to create a new set of file extensions and media types to describe different types of content such as oga for audio only files, ogv for video with or without sound (including Theora), and ogx for multiplexed Ogg. As of November 7, 2017, the current version of the Xiph. Org Foundation's reference implementation is libogg 1.3.3. Another version, libogg2, has been in development, but is awaiting a rewrite as of 2018. Both software libraries are free software, released under the New BSD License. Ogg reference implementation was separated from Vorbis on September 2, 2000. Ogg's various codecs have been incorporated into a number of different free and proprietary media players, both commercial and non commercial, as well as portable media players and GPS receivers from different manufacturers.

Ogg is derived from "ogging", jargon from the computer game Netrek, which came to mean doing something forcefully, possibly without consideration of the drain on future resources. Although it is sometimes assumed that the name "Ogg" comes from the character of Nanny Ogg in Terry Pratchett's Discworld novels, the format's developers say that is not true.

The "Ogg" bitstream format, designed principally by the Xiph. Org Foundation, has been developed as the framework of a larger initiative aimed at producing a set of components for the coding and decoding of multimedia files, which are available free of charge and freely re implementable in software and hardware. The format consists of chunks of data each called an "Ogg page". Each page begins with the characters "OggS" to identify the file as Ogg format. A "serial number" and "page number" in the page header identifies each page as part of a series of pages making up a bitstream. Multiple bitstreams may be multiplexed in the file where pages from each bitstream are ordered by the seek time of the contained data. Bitstreams may also be appended to existing files, a process known as "chaining", to cause the bitstreams to be decoded in sequence. A BSD licensed library, called "libvorbis", is available to encode and decode data from "Vorbis" streams. Independent Ogg implementations are used in several projects such as RealPlayer and a set of DirectShow filters. Mogg, the "Multi Track Single Logical Stream Ogg Vorbis", is the multi channel or multi track Ogg file format.

The Ogg project began with a simple audio compression package as part of a larger project in 1993. The OggSquish was in 2000 referred to as "a group of several related multimedia and signal processing projects". In 2000, two projects were in active development for planned release: Ogg Vorbis format and libvorbis—the reference implementation of Vorbis. Research also included work on future video and lossless audio coding. In 2001, OggSquish was renamed to Ogg and it was described as "the umbrella for a group of several related multimedia and signal processing projects". Ogg has come to stand for the file format, as part of the larger Xiph. org multimedia project. Squish became just the name of one of the Ogg codecs. The Ogg reference implementation was separated from Vorbis on September 2, 2000. Today, video in Ogg is found with the ogv file extension, which is formally specified and officially supported. Software and codecs that support ogm files are available without charge.

Although Ogg had not reached anywhere near the ubiquity of the MPEG standards (e. g., MP3/MP4), as of 2006, it was commonly used to encode free content (such as free music, multimedia on Wikimedia Foundation projects and Creative Commons files) and had started to be supported by a significant minority of digital audio players. Also supporting the Ogg format were many popular video game engines, including Doom 3, Unreal Tournament 2004, Halo: Combat Evolved, Jets'n'Guns, Mafia: The City of Lost Heaven, Myst IV: Revelation, StepMania, Serious Sam: The Second Encounter, Lineage 2, Vendetta Online, Battlefield 2, and the Grand Theft Auto engines, as well as the audio files of the Java based game, Minecraft. The more popular Vorbis codec had built in support on many software players, and extensions were available for nearly all the rest.

On May 16, 2007, the Free Software Foundation started a campaign to increase the use of Vorbis "as an ethically, legally and technically superior audio alternative to the proprietary MP3 format". People were also encouraged to support the campaign by adding a web button to their website or blog. For those who did not want to download and use the FSF's suggested Ogg player (VLC), the Xiph. Org Foundation had an official codec for QuickTime based applications in Windows and Mac OS X, such as iTunes players and iMovie applications; and Windows users could install a Windows Media Player Ogg codec.

By June 30, 2009, the Ogg container, through the use of the Theora and Vorbis, was the only container format included in Firefox 3.5 web browser's implementation of the HTML5 <video> and <audio> elements. This was in accordance with the original recommendation outlined in, but later removed from, the HTML5 draft specification (see Ogg controversy).

On March 3, 2010, a technical analysis by an FFmpeg developer was critical about the general purpose abilities of Ogg as a multimedia container format. The author of Ogg later responded to these claims in an article of his own.

Ogg audio media is registered as IANA media type audio/ogg with file extensions oga, ogg, and spx. It is a proper subset of the Ogg video media type video/ogg with file extension ogv. Other Ogg applications use media type application/ogg with file extension ogx; this is a superset of video/ogg. The Opus media type audio/opus with file extension opus was registered later in RFC and .