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.
There are two DivX codecs; the regular MPEG-4 Part 2 DivX codec and the H.264/MPEG-4 AVC DivX Plus HD codec. It is one of several codecs commonly associated with "ripping", whereby audio and video multimedia are transferred to a hard disk and transcoded.
Divx Formats
Divx Media Formats
DivX 6 expanded the scope of DivX from including just a codec and a player by adding an optional media container format called "DivX Media Format" ("DMF") (with a .divx extension) that includes support for the following DVD-Video and VOB container like features. This media container format is used for the MPEG-4 Part 2 codec.
- 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.
DivX Plus HD
DivX Plus HD is a marketing name for a file type using the standard Matroska media container format (.mkv), rather than the proprietary DivX Media Format. DivX Plus HD files contain an H.264 video bitstream, AAC surround sound audio, and a number of XML-based attachments defining chapters, subtitles and meta data. This media container format is used for the H.264/MPEG-4 AVC codec.
Divx Profiles
DivX has defined profiles which are subsets of MPEG-4/AVI and H.264/Matroska standards. Because the grouping is a specific subset of what is in the standards, there are certification processes for each of the profiles that device manufacturers must follow. Hence all DivX certified devices bearing a DivX logo will adhere to one of the profiles outlined in the table below as would any tools that support the DivX profiles.
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