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DivX

Developer(s)	DivX, Inc.
Stable release	7.1 / 2009-09-26; 57 days ago
Operating system	Cross-platform
Type	Codec/Media format/Media player
License	Proprietary
Website	DivX.com

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, 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.

[edit] History

The "DivX" brand is distinct from "DIVX" (Digital Video Express), an unrelated attempt by the now defunct U.S. retailer Circuit City to develop a video rental system requiring special discs and players.^[1] The winking emoticon in the early "DivX ;-)" codec name was a tongue-in-cheek reference to the failed DIVX system.^[2] 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.^[3][4] It is pronounced DIV-ex.

[edit] Early works

DivX ;-) (not DivX) 3.11 Alpha and later 3.xx versions refers to a hacked version of the Microsoft MPEG-4 Version 3 video codec (MPEG-4v3, Microsoft internal numbering scheme, unrelated to MPEG-4 parts) from Windows Media Tools 4 codecs.^[5][6] The video codec, which was actually not MPEG-4 compliant, was extracted around 1998 by French hacker Jerome Rota (also known as Gej) at Montpellier. The Microsoft codec originally required that the compressed output be put in an ASF file. It 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".^[7]

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.

[edit] Later works

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." ^[7]). 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"^[8] where he and Greenhall founded what would eventually become DivX, Inc.^[7]

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.^[9] Changes since then have tended to focus on speed, and encouraging wider hardware player support, while the company has also focused its time on the formats and next generation codecs.

[edit] DivX formats

[edit] DivX Media Format (DMF)

DivX Media Format

Filename extension	.divx
Type code	DIVX
Developed by	DivX, Inc.
Type of format	media container
Container for	DivX encoded video and other media
Extended from	Matroska, AVI

DivX 6 expanded the scope of DivX from including just a codec and a player by adding a media container format. This optional new file format introduced with DivX 6 is called "DivX Media Format" ("DMF") (with a .divx extension) that includes support for the following DVD-Video and VOB container like features.

• DivX Media Format (DMF) features:
  • Interactive video menus
  • Multiple subtitles (XSUB)
  • Multiple audio tracks
  • Multiple video streams (for special features like bonus/extra content, just like on DVD-Video movies)
  • Chapter points
  • Other metadata (XTAG)
  • Multiple format
  • Partial backwards compatibility with AVI

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.

[edit] DivX Subtitles (XSUB)

DivX, Inc. has, since DivX 6, added its own proprietary subtitle tracks that it calls "XSUB" (which has also been trademarked as XSUB)^{[citation needed]}. These subtitles are not text-based like many other subtitles, instead they are bitmap (digital image) based like vobsub subtitles for DVD-Video are. And like vobsubs for DVD-Video are supposed to be, XSUB does not come in standalone files but are only embedded in .divx containers, which can be created with Dr. DivX, (Dr. DivX can actually convert/encode XSUB from vobsubs inside DVD-Video). A .divx container can contain multiple XSUB subtitles in several languages.

[edit] DivX profiles

DivX has defined many profiles, which are sets of MPEG-4 features as determined by DivX. Because the grouping is different from what is specified in the MPEG-4 standard, there is a DivX-specific device certification process for device manufacturers.^[10] DivX's profiles differ from the standardized profiles of the ISO/IEC MPEG-4 international standard.

[edit] DivX Plus HD

DivX Plus HD is a DivX implementation of the Matroska video format, which they define as an .mkv file that contains an H.264 video bitstream, AAC surround sound audio, and a number of XML-based attachments defining chapters, subtitles and meta data.^[11]

[edit] DivX Video on Demand

DivX Video on Demand (DivX VOD) is DivX's verison of digital rights management (DRM), which allows content owners to control distribution in an effort to thwart piracy. DivX, Inc. has received format approval from major Hollywood studios including Sony, Paramount and Lionsgate, which has allowed content retailers to sell protected videos that will play on current and previous generations of DivX certified devices.^[12]

[edit] Playback software

DivX Player

Stable release	7.1 / 2009-09-26
Operating system	Mac OS X, Windows
Type	DivX media player
Website	http://www.divx.com/

The DivX codec and DivX Player are available for free at the DivX website.

On the 6th of January 2009, DivX 7 was released, which added H.264 video, AAC audio and Matroska container support, surpassing the restrictions of their previous formats.^[13]

[edit] DivX Player

DivX Player is a standalone media player for DivX encoded video. The player was created by DivX, Inc. and can be downloaded from the company's website. The Mac OS X version was introduced with DivX 6.5 on 2006-05-25. The precursor of this player is The Playa, one media player made by the Proyect Mayo team, that later became DivXNetworks.

[edit] Features

• Bundled playback of DivX (.divx/.avi) with .mp3 audio and DivX Plus (.mkv) with AAC audio
  • Other video formats playable via DirectShow
• Burn video discs
• Mouse gestures to control video (Mac OS X only)
• Media manager (Windows only)
• Play any QuickTime supported file (Mac OS X only)
• Play video as desktop background (Mac OS X only)
• Manage certified DivX devices to enable playback of purchased/protected content
• Playback of purchased/protected video content

[edit] DivX Plus Web player

DivX has also released the DivX Plus Web Player (formerly known as the DivX Browser Plug-In or DivX Web Player) demonstrating HD playback live inside major browsers for Windows and Mac OS.^[14]

[edit] Features

• Plug-in loads in Internet Explorer, Firefox and Chrome
• Plays embedded DivX/Xvid encoded .divx or .avi files with MP3 audio
• Also plays embedded DivX Plus HD, or H.264 video with AAC audio in .mkv

[edit] Hardware support

DivX, Inc. markets a certification program to consumer electronics and IC manufacturers for the purpose of guaranteed compatibility and playback of video files that fall within DivX profiles. Devices that have been DivX certified usually brandish one of the following marks:^[15]

• DivX Certified
• DivX Certified for HD
• DivX Plus HD
• DivX Connected
• DivX Certified for DivX Ultra

DivX certified devices have included DVD players, car stereos, mobile phones, televisions, blu-ray players, and even alarm clocks.^[16]

Aside from verifying proper decoding of DivX files, the certification also confirms the device can play back DivX Video on Demand content, which includes Hollywood content that can be purchased from Internet retailers.^[17]

[edit] Gaming system compatibility

On December 4, 2007, native MPEG-4 ASP playback support was added to the Xbox 360,^[18] allowing it to play video encoded with DivX and other MPEG-4 ASP codecs.^[19]

On December 17, 2007, firmware upgrade 2.10 was released for the Sony Playstation 3, which included official DivX Certification. Firmware version 2.50 (released on October 15, 2008) included support for the DivX Video on Demand (DivX VOD) service, and firmware version 2.60 (released on January 20, 2009) included official DivX Certification and updated Profile support to version 3.11.^[20]

[edit] Encoding applications

[edit] DivX Converter

DivX Converter is a drag-and-drop transcoding application included as part of the DivX 7 software bundle. Although DivX for Windows and DivX for Mac both include DivX Converter, only DivX for Windows includes an option for encoding to DivX Plus HD.

[edit] Features

• Bundled input support of uncompressed .avi and H.264/MKV
  • Optional plug-in can be purchased to enable MPEG-2 as input
  • Other inputs supported via DirectShow
• Outputs DivX (.divx with MP3 audio) for free
• Outputs DivX Plus HD (.mkv with AAC audio) for 15 days with option for upgrade (Windows only)
• Customers that pay for DivX Pro can access additional features of the DivX codec in Video for Windows applications

[edit] DivX H.264 Encoder

When using DivX 7 in the converter the only option available is to limit filesize, but the more configurable DivX264.exe CLI client is available from DivX Labs.^[21] Since it can only create raw H.264 streams a Matroska muxer must be used.

[edit] Dr. DivX OSS

Dr. DivX is an application created by DivX, Inc. that is capable of transcoding many video formats to DivX encoded video. The original closed source Dr. DivX terminated at version 1.06 for DivX 5.21, that was the last version of DivX capable of running under Windows 9x/Me. An open source version has been made, which supports DivX 6. Dr. DivX offers greatly expanded features over the free DivX Converter application, that was bundled with the codec from version 6 onwards.^[22]

Other applications exist, such as AutoGK, VirtualDub, TMPGEnc and DVDx.

[edit] Competitors

The main competitors in the proprietary commercial video compression software market are Microsoft's Windows Media Video series, and Apple Inc.'s QuickTime.

While the DivX codec has long been renowned for its excellent video quality, the free and open source Xvid codec offers comparable quality. Both the DivX encoder and the Xvid encoder are compliant with MPEG-4 Part 2 (MPEG-4 ASP). However, the most commonly used DivX encoding profile (Home Theater)^[23] does not employ the same MPEG-4 ASP features enabled in the most commonly used Xvid encoding profile (home).^[24] In a series of subjective quality tests at Doom9.org between 2003 and 2005, the DivX encoder was beaten by the Xvid encoder every year.^[25] 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.

[edit] Adware in versions before 5.2

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At one point^[when?], DivXNetworks offered for download an "ad supported" version of their DivX Professional product free of charge.^{[citation needed]} The ads were delivered by the GAIN ad server software.^{[citation needed]} Users could select the "ad supported" download rather than the commercial professional version or the free version. Additionally, users were informed during installation of the ad-supported version that the Gator software would be installed on their PC and were presented with a license agreement to which they had to consent in order to continue the installation.

DivXNetworks announced on the DivX web site that, from 15 July 2004, no further DivX software would incorporate adware. 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.^{[citation needed]} The DivX Player remains available free of charge.

[edit] See also

DivX, Inc.

Related technologies

• Audio Video Interleave (.AVI)
• Matroska (.MKV)
• MPEG-4 Part 2
• H.264/MPEG-4 AVC
• Xvid
• FFmpeg
• ffdshow

General Topics

• List of codecs
• Comparison of video codecs
• Container format (digital)
• Comparison of container formats

[edit] References

[edit] External links

• DivX Labs Community DivX website, with betas and ongoing projects
• DivX resources at the Open Directory Project