Information AboutDirac |
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Dirac is a prototype Algorithm for the encoding and decoding (see '' Codec '') of raw video. It was presented by the BBC in January 2004 as the basis of a new Codec 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 PAL TV definition (720 x 576i pixels per frame at 25 Frames Per Second ) in real time; the current version can decode about 17 frames per second on a 3 GHz PC but extensive optimisation is planned. Similar to common video and VC-1 . MPEG-2 is the previous generation video codec used in the standard DVD format today. Dirac is one of several projects attempting to apply wavelets to video compression. Others include . Also of note is the Xiph.org Foundation 's Tarkin , developed by the creators of the Vorbis audio codec, which offered impressive performance but saw only limited adoption. Tarkin showed much promise, but was put on hold so its creators could focus their efforts on Theora , a less experimental video codec based on On2 Technologies' VP3 . Wavelet compression is not merely experimental. It has already proven its viability in the JPEG 2000 compression standard for photographic images. However, it has not been shown to provide substantially superior compression capability than other techniques based on more traditional block-based coding. For example, H.264 is often as good or better in compression capability for still images, despite the wavelet-based design of JPEG-2000. The primary benefits of JPEG-2000 relative to other codecs are functionality aspects, such as scalability features, rather than compression capability. The codec is named in honour of the British Scientist Paul Dirac . LICENSE The experimental and unfinished Dirac codec, written in C++ , was released under an Open Source license at SourceForge on 11 March 2004 . While the BBC owns some patents on Dirac, they have irrevocably granted a royalty-free license for their Dirac related patents to all of humanity. In addition, the BBC have checked (by extensive patent search) that Dirac doesn't infringe any third party patents, enabling the public to use Dirac for any imaginable purpose. The BBC releases Dirac under the Mozilla Public License which also allows GPL and LGPL programs to use it. This may accelerate its adoption and lower entry costs into the emerging industry of Internet Television . SEE ALSO
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