DivX is a brand name of products created by DivX, Inc. (formerly DivXNetworks, Inc.), including the DivX Codec which has become popular due to its ability to compress lengthy video segments into small sizes while maintaining relatively high visual quality. The DivX codec uses lossy MPEG-4 Part 2 compression, also known as MPEG-4 ASP, where quality is balanced against file size for utility. It is one of several codecs commonly associated with "ripping", whereby audio and video multimedia are transferred to a hard disk and transcoded. Many newer "DivX Certified" DVD players are able to play DivX encoded movies, although the Qpel and global motion compensation features are often omitted to reduce processing requirements. They are also excluded from the base DivX encoding profiles for compatibility reasons.
The "DivX" brand is distinct from "DIVX" (Digital Video Express), an unrelated attempt by the U.S. retailer Circuit City to develop a DVD rental system requiring special discs and players. The winking emoticon in the early "DivX ;-)" codec name was a tongue-in-cheek reference to the failed DIVX system. The DivX company then adopted the name of the popular DivX ;-) codec (which was not created by them), dropped the smiley and released DivX 4.0, which was actually the first DivX version (that is, DivX ;-) and DivX are two different things created by different people, the former is not an older version of the latter). The DivX name is its trademark. It is pronounced DIV-ex.
DivX ;-) 3.11 Alpha and later 3.xx versions refers to a hacked version of the Microsoft MPEG-4 Version 3 (MPEG-4v3, Microsoft internal numbering scheme, unrelated to MPEG-4 parts) video codec (which was actually not MPEG-4 compliant), extracted around 1998 by French hacker Jérome Rota (also known as Gej) in Montpellier. The Microsoft codec, which originally required that the compressed output be put in an ASF file, was altered to allow other containers such as Audio Video Interleave (AVI). Rota hacked the Microsoft codec because newer versions of the Windows Media Player wouldn't play his video portfolio and résumé that were encoded with it. Instead of re-encoding his portfolio, Rota and German hacker Max Morice decided to reverse engineer the codec, which "took about a week".
From 1998 through 2002, independent enthusiasts within the DVD-ripping community created software tools which dramatically enhanced the quality of video files that the DivX ;-) 3.11 Alpha and later 3.xx versions could produce. One notable tool is Nandub, a modification of the open-source VirtualDub, which features two-pass encoding (termed "Smart Bitrate Control" or SBC) as well as access to internal codec features.
In early 2000, Jordan Greenhall recruited Rota to form a company (originally called DivXNetworks, Inc., renamed to DivX, Inc. in 2005) to create clean-room DivX and steward its development. This effort resulted first in the release of the "OpenDivX" codec and source code on January 15, 2001. OpenDivX was hosted as an open-source project on the Project Mayo web site hosted at projectmayo.com (the name comes from "mayonnaise", because, according to Rota, DivX and mayonnaise are both "French and very hard to make." ). The company's internal developers and some external developers worked jointly on OpenDivX for the next several months, but the project eventually stagnated.
In early 2001, DivX employee "Sparky" wrote a new and improved version of the codec's encoding algorithm known as "encore2". This code was included in the OpenDivX public source repository for a brief time, but then was abruptly removed. The explanation from DivX at the time was that "the community really wants a Winamp, not a Linux." It was at this point that the project forked. That summer, Rota left the French Riviera and moved to San Diego "with nothing but a pack of cigarettes" where he and Greenhall founded what would eventually become DivX, Inc.
DivX took the encore2 code and developed it into DivX 4.0, initially released in July 2001. Other developers who had participated in OpenDivX took encore2 and started a new project—Xvid—that started with the same encoding core. DivX, Inc. has since continued to develop the DivX codec, releasing DivX 5.0 in March 2002. By the release of version 5.2.1 on September 8, 2004, the DivX codec was substantially feature-complete. Changes since then have tended to focus on speed, and encouraging wider hardware player support.
This new "DivX Media Format" also came with a "DivX Ultra Certified" profile, and all "Ultra" certified players must support all "DivX Media Format" features. While video encoded with the DivX codec is an MPEG-4 video stream, the DivX Media Format is analogous to media container formats such as Apple's QuickTime. In much the same way that media formats such as DVD specify MPEG-2 video as a part of their specification, the DivX Media Format specifies MPEG-4-compatible video as a part of its specification. However, despite the use of the ".divx" extension, this format is an extension to the AVI file format. The methods of including multiple audio and even subtitle tracks involve storing the data in RIFF headers and other such AVI hacks which have been known for quite a while, such that even VirtualDubMod supports them. DivX, Inc. did this on purpose to keep at least partial backwards compatibility with AVI, so that players that do not support the new features available to the .divx container format (like interactive menus, chapter points and XSUB subtitles) can at least play that primary video stream (usually the main movie if the DMF file contains multiple video streams like special features like bonus materials). Of course, the DivX codec and tools like Dr.DivX still support the traditional method of creating standard AVI files.
The DivX codec and DivX Player are available for free at the DivX website. Paying customers can access additional features of the DivX codec in the registered version, known as DivX Pro, and can also use DivX Converter, a one-click encoding application as a revamp of Dr.DivX and associated encoding tools (such as the Electrokompressiongraph, or EKG, which helped increase the viewability of highly compressed high-motion scenes). The latest version of DivX Converter for Windows is 6.5, and the latest version of DivX Converter for Mac is 1.2. Current versions however do access a domain name server.
|Handheld||Portable||Home Theater||High Def|
|Max. resolution||(px×px×Hz)||176×144×15||352×240×30, 352×288×25||720×480×30, 720×576×25||720×480×30, 720×576×25||1280×720×30; 6.5: 1920×1080×30|
|Max. average bitrate||(Mbit/s)||0.2||0.768||4||4||4|
|Max. peak bitrate||(Mbit/s)||0.4||2||8||8||20|
|Min. VBV buffer size||(KiB)||33||128||384||384||768|
While DivX has long been renowned for its excellent video quality, its free and open source equivalent Xvid today offers comparable quality, also based on MPEG-4 Part 2 (MPEG-4 ASP). In a series of subjective quality tests at Doom9.org between 2003 and 2005, the DivX codec was beaten by Xvid every year. Similar tests were not undertaken for newer versions.
The open source library libavcodec can decode and encode MPEG-4 video that can be encoded and decoded with DivX (and other MPEG-4 codecs, such as Xvid or libavcodec MPEG-4). Combined with image postprocessing code from the MPlayer project, it has been packaged into a DirectShow filter called ffdshow, which can be used for playback with most Windows video players. This library is highly customizable and offers a great variety of features to advanced users.
Since the standardization of H.264/MPEG-4 AVC, also known as MPEG-4 Part 10, a new generation of codecs has arisen, such as x264 and Nero AG's Nero Digital AVC codec. Despite being at a relatively early stage of development, these codecs out-performed DivX in Doom9's 2005 quality test, thanks to the more advanced features of MPEG-4 Part 10. Part 10's advanced features come at a cost: AVC decoding is two to three times more CPU intensive compared to MPEG-4 ASP; lightweight algorithms used in faster modes of DivX (or Xvid) codec allow one to achieve reasonable quality in a small fraction of time required to take advantage of all features of AVC. So far, DivX Labs has released a new alpha of a new codec based on the H.264 specification.
Due to the generally hostile opinion towards adware on the Internet, DivXNetworks announced on the DivX web site that, from July 15, 2004, no further DivX software would incorporate any adware. Free versions of DivX Pro before 5.2 typically contained spyware. From 5.2 onwards, including version 6, no spyware was included. When accessed in April 2007, the Professional version of DivX was only available in the form of a paid release or a 15-day free trial with no adware included. The DivX Player remains available in a long-term free license.