DivX codec
This page is meant for newbies who wonder if they should install the DivX codec. If you know what codecs are all about, you won't need to read further.
Videos on the web
Compared to text, scripts, and even large images, videos need much more diskspace. Much, much more! Of course, sequences of hundreds of images make up huge files that require lots of bandwidth and quite a long time for downloading. Using a normal dial-up connection you will need at least a few minutes to download a video with several minutes length. Probably this sounds familiar if you are used to downloading MP3 music.
Compression
If a video is simply digitalised, it will consume excessive diskspace. Let's say that each pixel in each single image is described by a number coding its colour. Even more space is required for sound. On modern computers with several GB hard disks this is no problem, but on the web this is impossible. Of course, the images can be described with fewer words. A more concise description will be based on a special format and, for example say something like "the first 100 pixels are black" instead of "pixel 1 is black, pixel 2 is black, pixel 3 is black, ....". Even more conciseness (compression) is achieved by comparing consecutive images ("image 7 is the same as image 6 except for ..."). Let's compare this to translating a text into a language which is much more concise than he original one (for example, the same text in English should be shorter than the corresponding German source text - but with video compression the effect is much more significant). Usually, compression doesn't mean a loss of quality, it's just a way to store the same data with fewer bytes. Occasionally, compression methods may sacrifice a little bit of the quality in order to achieve a much greater compression rate.
What is a codec?
A codec is an algorithm for compressing data. In simpler words, it is a dictionary for the translation of the source into a much more concise language. A codec is not a program - if you have only a dictionary you can't read a foreign newspaper. You need a program which does the compression, like an interpreter. VirtualDub, for instance, is a free program for the compression of video files (you don't need it unless you want to produce videoclips yourself). Your player, e.g. Windows Media Player, is able to decompress the file in order to display it pixel-by-pixel on your screen. Both programs are excellent interpreters, but you have to supply them with the dictionary, i.e. the codec. Some codecs are distributed with the programs, but others are not included. DivX 5.0.2, which has been used here, is not included. This is because it is freeware and not a Microsoft product. It is one of the most powerful freely available codecs and has therefore been used here.
Why should I install DivX ?
DivX is a widely used software, and if you don't have it the reason is probably that you haven't downloaded many videos yet. Compression by DivX becomes more and more popular and saves heaps of bandwidth. It it something like MP3 for videos. DivX does no harm to your computer. It is not a program, it contains no spyware and doesn't transfer any data to anybody. Of course, it does not contain any virus. It is just 3 MB of software that does not interfere with any other programs. It is only called when you use a player in order to play a DivX encoded video. It will not create any icon and can easily be removed completely by the accompanying uninstall routine.
How to install DivX
It is very easy to install DivX. Simply go to http://www.divx.com/divx . There you choose DivX (DivX Pro is not necessary, but equally suitable), there is no need to select the version with Adware [1]. Click on "download" [2] and save the installation routine "DivX502Bundle.exe" to any folder on your hard disk (you may choose "Temp" and delete the file after the installation). With MS Internet Explorer you may also "open the file from its current location" without prior saving to your hard disk. Simply execute the program (double-click on "DivX502Bundle.exe" in the folder you selected) and follow the instructions. You can accept all default settings if you like. In one step you will be asked what software you want to install - you can select the codec and additionally the DivX Player. If you'd like to test the player (it will create a desktop icon), simply continue, otherwise uncheck the corresponding box and install the codec only. The player is not required to view the videos, as the codec will create a plugin in Windows Media Player or other players. In fact, the DivX player is not really suitable to view the videos on this site, because it can display the images but not produce the sound. After you have finished the installation you'll be able to watch any DivX encoded video. That's all, you don't have to do anything else. There is NO need to restart your computer after the installation.