Theora

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Theora is developed by the Xiph.Org Foundation free video codec and video format, which is part of the Ogg container format. Building on the VP3.2 codec company On2 Technologies is a patent-free alternative to proprietary low - bit-rate video codecs such as RealVideo, DivX or Windows Media Video on offer.

Currently, it is planned, Theora to connect with RTP to improve the streaming qualities.

History

In June 2002, the company On2 Technologies handed the video codec VP3.2 to the Xiph.Org Foundation to let him develop further an open source under a BSD - style license. Although VP3.2 is patented, On2 had the right to tax-free use of the respective patents released, opening up the possibility to use Theora without patent issues or limitations. The further developed in addition under the name Theora codec was released on 25 September 2002 in a first alpha version. Compared with Theora VP3 is more flexible in the quantization. The name Theora came here from Theora Jones, a character from the cyberpunk television series Max Headroom.

On 1 June 2004 bitstream specified freeze ( with libtheora 1.0alpha3 ), which meant that all the videos that have been created with the codec versions as of this time and later, can be read with future codec versions. In summer 2004, followed by the first large-scale Theora streams of various open source conferences to provide the capabilities of the codec under test. During this time also the RealPlayer 10 was released. He supported the first widespread video player Theora, but partly had for Microsoft Windows still installed afterwards a plugin.

On 15 December 2004, the Theora I specification was issued.

On 17 April 2005, announced that a C # port of the video codec was created for the graphics engine OGRE. In June 2005, the software project Cinelerra implemented the ability to process Theora encoded videos.

On 22 September 2007, the first beta version of Theora reference implementation ( libtheora ) was issued. This version differs according to the developers of the final version only by the not yet complete documentation and missing project files for different development environments.

On 3 November 2008, the final was released libtheora 1.0.

The coding efficiency remained behind the current commercial alternatives still significantly ( an encoded with the Theora codec Video requires about 30 % more space than a comparable quality to H.264 ). With support from Red Hat and Mozilla is working on a new reference encoder called Thusnelda. Improved motion search, use the opposite VP3 expanded opportunities in the quantization and smarter bit allocation he gets much more out of the codec than the old one, based on the VP3 encoder encoder, which still does not make use of the new possibilities of Theora format. This written from scratch encoder was published in September 2009 as Theora 1.1. In addition to improved coding efficiency, which makes Theora now competitive, it is also significantly faster. Among other things, saves a lot in computationally complex motion search by preliminary estimate of the expected movement of a block of past movement. Currently Ptalarbvorm working on libtheora 1.2 under the code name.

With the release of VP8 under a free license by Google is assumed that the interest in Theora will be significantly less in the future.

Playback

Embedding in HTML5

According to the original draft HTML5 support the following browsers Theora for video element:

  • Google Chrome ( since version 3.0)
  • Mozilla Firefox ( since version 3.5)
  • Opera ( since version 10.5)

Browser plug-ins

  • Annodex Plugin by OggPlay
  • Cortado, a Java applet Itheora, a PHP implementation of Cortado

Supporting Media Frameworks

  • DirectShow when using a DirectShow filter
  • GStreamer Theora via module supports GStreamer -based applications such as Totem and Songbird
  • Phonon
  • QuickTime via Xiph QuickTime Components

Supporting applications

  • FFmpeg ( own implementation )
  • Helix Player
  • Miro Media Player (initially known as Democracy Player )
  • MPlayer with GUI
  • Songbird
  • VLC ( native support )
  • xine and all libxine - based playback applications such as Kaffeine

Encoding

There are several programs from other manufacturers that support the encoding by means of the Program - libtheora library:

The libtheora - program library contains the reference implementation of the Theora specification for encoding and decoding. She is still being developed by the Xiph.Org Foundation, and can be used under the terms of the BSD license. In addition, various media frameworks provide support for Theora.

The open source DirectShow audio / video codec ffdshow can encode and decode on the interface Video for Windows ( VFW ) Theora video. This Theoras be used alpha -4 libraries. However, not all settings through the GUI accessible. Even the GStreamer framework supports Theora.

Processing

Direct Transfer ( Streaming)

The following programs can transfer Theora videos directly:

Theora Streaming Studio allows connection to an Icecast server.

Libtheora versions

Versions of the Theora reference implementation ( libtheora ):

Technical standard BSD licenses Videocodec Real-Time Transport Protocol Max Headroom (TV series) Cortado (software) Java-Applet Songbird (software) Miro (software) SUPER © LiVES Dirac (video compression format) Ogg#Ogg codecs Ogg Writ XML Shareable Playlist Format cdparanoia Chris Montgomery
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