XviD

Xvid is an implementation of the standard MPEG-4 (left 2) of coding video and distributed under public License general GNU (LPG). At the origin based on OpenDivX, Xvid was developed by a group of volunteers after the sources of OpenDivX were not available any more.

Xvid supports the profile Advanced Simple MPEG-4 (share 2) comprising additional algorithmic tools compared to the profile Simple such as the images B, the compensation of movement to the quarter of pixel, the total compensation of movement like two methods of quantification (H.263 and MPEG). As regards coder, certain techniques were developed such lumi masking and quantification by lattice.

The methods and algorithms of the standard MPEG-4 (share 2) are patented and the licenses of use of this technology are managed by MPEG it. However, Xvid does not respect the payment of a royalty (“royalties”) and thus implements the technology developed by consortium MPEG free. Because of that, the version 0.9.x of Xvid were declared illegal in the countries where the patents of this type have course (it is not the case in Europe) . Starting from the version 1.x, Xvid is distributed under GNU/GPL without geographical restriction.

The main competitor of Xvid is DivX. Whereas Xvid is a Free software (entirely free and modifiable), DivX is distributed like Gratuiciel (just binary files and it is illegal to modify them) or then in version pro, paying, comprising the coder. It should in addition be noted that DivX pays royalties with MPEG it since it “borrows” technologies of the standard MPEG-4.

History

In January 2001, DivX Networks launched OpenDivX as part of the Project Mayo (which was to be a place of regrouping for the codecs multi-media OpenSource). OpenDivX was then a codec OpenSource, based on codec MPEG-4 MoMuSys. However, the source code was placed under a restrictive license and only the members of DivX Advanced Research Center (DARC) had a right of access in writing with the source code on the waiter CVS of the project. At the beginning of 2001, a member of the DARC, Sparky, wrote a version improved of the coder, called encore2 . In April, this version was withdrawn from CVS without warning. The explanation given was: “We chiefs decided not to make it public for the moment” (We bumps decided that we are not ready to cuts it in public yet) .

In June 2001, the developers started to complain about the weak activity of the project. A little later the DARC published a beta release (and ClosedSource) of their coder DivX 4, who was based on encore2. Some then showed DivX Networks to have launched OpenDivX with an only aim of collecting ideas to re-use them in their codec DivX 4, while others were disappointed that this project was qualified “open source”. It is after all that a new branch of OpenDivX was created: Xvid.

Discusses with Sigma Designs

In July 2002, Sigma Designs leaves a codec video MPEG-4 named REALmagic MPEG-4 Video codec . Some time later, of the people testing this new codec finds that it contains much code of the Xvid project. Sigma Designs is then contacted and confirms that a programmer based REALmagic on Xvid, but ensures that the code LPG should be replaced to avoid the violations of the LPG (in this case obligation to publish the modifications which one brings on a source code under this license).

When Sigma Designs delivers the announced version récrite of codec REALmagic, the team of the Xvid project disassembles it and concludes that there remains still code of Xvid, the version was modified to try to mask the presence of parts of Xvid. The developers of XviD decide to stop the development and turn to the public to force Sigma Designs to respect the terms of the license LPG. After articles were published on Slashdot or The Inquirer , in August 2002 Sigma Designs agrees to publish their source code.

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