Definition: DivX

(1) A family of video codecs, formats and software from DivXNetworks, Inc., San Diego, California that is popular for downloading movies from the Internet. Based on MPEG-4, DivX can compress a DVD movie to fit on a CD, and DivX HD can reduce an HD movie to fit on a DVD. The DivX software provides tools for encoding in DivX and MPEG-4, as well as a player for DivX, MPEG-4 and other video formats.

In the late 1990s, DivX was the first video codec for the Windows AVI container format that provided strong compression along with good picture quality. Enabling acceptable video to be streamed over the Internet, DivX quickly became the predominant video compression method for the AVI format (see AVI).

DivX Formats: AVI and MKV Containers
From its development as a codec, DivX evolved into a specification for the AVI container that uses the DivX or Xvid codecs and MP3 or AC-3 audio. Developers creating DivX Media Format (DMF) AVI files, which use an .AVI or .DIVX file extension, adhere to the DivX encoding guidelines. The DivX format also became popular on Divx-certified consumer electronics devices, including DVD and Blu-ray players, portable video players and mobile phones.

The newer DivX Plus HD format uses the MKV/Matroska container with H.264 video and AAC audio (see Matroska). DivX Plus HD supports multilingual subtitles, surround sound and multiple audio tracks and titles. Like the DivX format, encoders must comply with certain specifications.

Size Comparison
The following table of file sizes comes from an actual video that was available on the Web in multiple formats. Note that the iPod and PSP formats support only tiny screens. See XviD.

                               File Size
   Format                        (MB)

   PlayStation Portable (PSP)     42
   iPod                           55

   DivX                           61
   MPEG-4                        130
   QuickTime (MOV)               135
   Windows Media (WMV)           191

(2) (Divx) (DIgital Video EXpress) A DVD rental system rolled out in 1998 and taken off the market one year later due to poor sales. A joint venture of Circuit City and a Los Angeles entertainment law firm, Divx was a special type of DVD disc playable only in a Divx-enabled DVD player. Consumers paid a rental charge for the non-returnable disc, which was good for two days after its first viewing. Additional time as well as unlimited use could be purchased via modem from the Divx player. A major problem was that Divx discs registered to a specific machine could not be played on other Divx players.

(3) A copy of the DVD copy protection decryption algorithm that was lifted from a media player and passed around hacker sites. The Divx name was used in honor of the defunct Digital Video Express system.