This article is about the codec. For the British physicist, see Paul Dirac.

Dirac is a prototype algorithm for the encoding and decoding (see codec) of raw video and sound. It was presented by the BBC in January 2004 as the basis of a new file format for the transmission of video over the Internet.

The codec is still not finished as a product, and thus regarded as still being under development. "The immediate aim is to be able to decode standard digital TV definition (720 x 576 pixels at 25 frames per second) in real time; the current version can decode a quarter-standard resolution at 20 frames per second, which is enough for Internet streaming." [1] (http://uk.news.yahoo.com/040812/175/f06i1.html)

Similar to Microsoft's WMV video-format codec it can compress any size of picture from low-resolution QCIF (176x144 pixels) to HDTV (1920x1080) and beyond, and a powerful compression-algorithm which "seems to give a two-fold reduction in bit rate over MPEG-2 for high definition video"[2] (http://www.bbc.co.uk/rd/projects/dirac/overview.shtml).

Although the codec seems superficially similar to WMV it differs from Microsoft's in that it uses a compression method based on wavelets. Another notable difference is that the Dirac project is Open Source, potentially lowering entry costs into the emerging industry of Internet television.

While the BBC owns some patents on Dirac, they have irrevocably given royalty-free license of the Dirac related patents to all of humanity, enabling the public to utilize Dirac for any imaginable purpose. The BBC releases Dirac under the Mozilla Public License which also allows GPL and LGPL programs to use it.

The codec is named in honour of the British scientist Paul Dirac.

Licence

The experimental, and unfinished codec written in the programming language C++ was released under an Open Source licence at SourceForge on the 11th of March 2004.

See also

• Internet television

External links

• BBC (http://www.bbc.co.uk/) which announced the codec
• BBC Research and Development (http://www.bbc.co.uk/rd/) the Department (largely) working on the codec
• Dirac (http://www.bbc.co.uk/rd/projects/dirac/overview.shtml) project page on BBC's servers
• Dirac project (http://sourceforge.net/projects/dirac/) on SourceForge

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