DivX

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DivX

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Basic data

developer TiVo Corporation
Current  version 10.8.6
(January 23, 2018)
operating system Windows , macOS
category Video codec
License proprietary
German speaking Yes
divx.com/de

DivX ( English [ ˈdɪvɛks ]) is an MPEG-4 compatible video codec . The codec is known for its ability to compress large video files relatively heavily while maintaining good quality.

History of DivX

DivX 3.11 and earlier versions of the codec emerged after Microsoft's MPEG-4 codec was hacked in 1998 . A French hacker named Jérôme Rota (pseudonym: Gej, Occitan for "crazy") extracted the codec from a beta version of Windows Media Player . The "Project Mayo" was born, which four other programmers joined shortly afterwards. In the early versions of the “DivX Player” it was still adorned with the “Project Mayo” emblem, which was later removed due to many inquiries from users. The hack modified the Microsoft codec to be able to save the compressed video not only as an ASF file but also as an AVI file. In addition, the original Microsoft codec only supported bit rates of up to 256  kbps ; in the hacked version, however, it was up to 6,000. The company DivXNetworks, Inc. founded by Rota later developed a completely new version to avoid patent infringements in the USA. DivXNetworks has applied for a patent on the new codec in the USA .

In January 2001, DivXNetworks founded OpenDivX the project as part of Mayo , which is open source - Multimedia to house projects. OpenDivX was an open source MPEG-4 video codec that was written from the ground up; however, the code was placed under a limited license and only members of the DivX Advanced Research Center (DARC) had write access to CVS . In spring 2001, DARC member Sparky wrote an improved version of the encoder core, called encore2 , which was then removed from the CVS without warning. Sparky's statement was, "We (our superiors) decided we weren't ready to show it to the public just yet" (translated).

In July 2001, the developers began over a lack of activity of the project Mayo to complain, as the last source code change was already months ago, improvements of program errors were ignored and the promised documentation had not appeared. Shortly thereafter, DARC released a beta version of their closed source and commercial DivX-4 codec, which was based on encore2 , with the declaration “What the community really wants is a Winamp , not a Linux ” (translated). Some accused DivXNetworks of just starting OpenDivX to collect other people's ideas and then use them in their DivX-4 codec; some were disappointed that code development had stagnated but wanted to keep working on it, while still others were angry at the way DivXNetworks is handling what is known as an open source project. Then a fork was created by OpenDivX using the last version of encore2 that a few people downloaded before it was removed. Since then, the entire OpenDivX code has been replaced and published and further developed under the GPL as the Xvid codec.

DivX formats

A typical 100-minute long film is six to eight gigabytes on a DVD ; DivX video compression allows the film to be saved on a CD-ROM (650 to 700 MB ). The quality remains relatively high even at bit rates of 650 to 1,000 kBit / s, which are lower than MPEG-2 , but compression artifacts can occur in scenes with a lot of movement .

With the further development of the DivX codec, technical improvements have repeatedly been achieved. Above all, the multi-pass coding with variable bit rate, supported from version 4, has contributed to this, in which the original file is analyzed with regard to the complexity of the successive individual images in a first coding pass . The final video file is only created in one of the subsequent runs (usually one). The advantage here is that if the storage space requirement remains the same, complex and fast moving scenes are assigned a higher bit rate, while this is again reduced for slow, calm image sequences.

Newer versions also support various MPEG processes (so-called MPEG tools ) such as anamorphic coding and global motion compensation , which in turn leads to a reduction in storage space requirements with approximately the same image quality.

The success of DivX in the home environment has increased so much in recent years that the codec is also supported by DVD players . Various digital cameras and cell phone models also have a video recording function in DivX format.

In order to consolidate itself further in the home area, the range of playback options will be further increased by further developing the codec for use on other platforms. There is also the option of compressing films in resource- and memory-saving formats for use on PDAs and handhelds as well as for demanding home theater use in high-definition formats ( high definition television ).

Movies with high-resolution images require both more processor performance and more memory. However, the storage requirement is significantly below that of a comparable MPEG-2 film.

From version 7.0 DivX supports the H.264 format and the Matroska container, but only via a very simple conversion program called DivX Converter . DivX 7 also has an H.264 decoder for DirectShow . The actual codec is still delivered in version 6.9.2, without H.264 and without Matroska support. The DivX H.264 command line encoder is currently available for download as a preliminary version on the “DivX Labs” website. A free registration is required before the download . The command line encoder supports AviSynth as input and outputs H.264 raw data (without container ).

See also

Web links

Individual evidence

  1. ↑ DivX software version history. In: force.com. Retrieved February 1, 2018 .
  2. ^ Damien Cave: Escaping the Napster trap ( Memento from November 29, 2010 on WebCite ) (English).
  3. ↑ lists.xiph.org
  4. ↑ forum.doom9.org