Dirac (video compression format)
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Dirac is a May 2004 report published by the BBC video codec to be a free alternative to codecs, such as Microsoft's Windows Media Video or those of the Moving Picture Experts Group. In particular, care is taken that no be used by third parties patented technologies.
Dirac was completed on 21 January 2008. The reference implementation is written in the programming language C . In addition, under the name of Schrödinger, a project was started, which has an optimized and portable implementation of the Dirac specifications to the destination.
This first implementation was completed on 11 March 2008 and is in version 1.0 before.
The under the Mozilla Public License 1.1 ( MPL) published an open source codec allows relicensing of the code under the GNU General Public License 2.0 ( GPL) and the GNU Lesser General Public License 2.1 ( LGPL).
To achieve the highest possible compression rates without artifact formation, used Dirac - unlike competing formats such as H.264 - a discrete wavelet transform as well as techniques such as motion compensation and arithmetic coding, the video codec in addition to the low memory consumption at high resolutions for Internet Streaming applications can seem suitable. The range of resolutions ranging from QCIF ( 176 × 144 pixels ) to HDTV ( 1920 × 1080 pixels ) and higher. When released in a resolution of 1920 × was a halving of the data rate compared to the MPEG -2 standard, the speech by 1080 pixels. So that its compression ratio would be comparable to that of H.264.
In addition to the free software community also various universities develop the codec on.