If you download a video file say thru BitTorrent and find that you can play it; it is most likely because you donÃ¢â‚¬â„¢t have DivX installed.
DivX is a type of video encoding format that produces DVD and HDTV quality at a higher compression rate than other video encoders. Video files that are created with DivX end up being much smaller than those that are not, so it has become vary popular on the internet. Of course smaller files mean that the same content can be downloaded much faster then there larger counter parts.
Windows Media player will automatically download most codecs (COder / DECoder ) if they are missing; however this is not the case with DivX. You must download and install DivX manually to use it. Here is the link where you can find DivX:
Note: The free version is good enough to just play videos.