A codec (from coder/decoder)is an algorithm, or method, for compressing media files so they take up less space and can be more easily stored or transmitted over the Internet. Most codecs trade a loss of quality in return for increased compression.
The most famous codec of all is MP3, which has revolutionised the distribution of music. Technically, MP3 is actually one small part of a family of codecs called MPEG, which has been developed for the digital storage of video information (see July issue, page 24). MPEG-4 is the latest and most efficient in a line of video codecs, and DivX is an offshoot of it that has the potential to do for movies what MP3 has done for music.
Using DivX, a 30-minute TV program can be compressed to around 30MB and a full-length movie can be made to fit on a CD, without significant loss of quality. Many enthusiasts have encoded their favourite movies, video clips and TV programs using DivX, and made them available for downloading.
To play these files, you need to obtain and install a compatible media player and the DivX codec. These can be downloaded from many sources on the Net, including www.divx.com and www.projectmayo.com. There are two main types for Windows users: the DivX Playa, which is a stand-alone media player that can show DivX files, and DivX for Windows, which is a plug-in that allows an existing program, such as Windows Media Player version 6.2 or later, to decode DivX. The installation files for both of these programs are available on this month's cover CD. An even later version, DivX 4.0 beta, was released just as we went to press, and can be downloaded from www.divx.com.
Installation of both versions is quite straightforward - if you already have Windows Media Player, the DivX for Windows setup program will automatically register the codec with the application. The Playa, of course, is self-contained. Both proved able to play most downloaded DivX files with good quality reproduction on an 800MHz Pentium III.
Some files wouldn't work, evidently due to having been created with a different version of DivX. Experienced DivX users can rectify this problem by searching for different versions of the codec on the Net, and installing a number of them. With a wide enough net of codec versions, you'll be able to play almost any video file format that's out there.
DivX for Windows 0.3 and DivX Playa 0.5