DX50 is a secondary fourcc code for DivX 5.xx and can be played back with DivX 5.xx
If you need a codec package that gives you support for all the major video formats in use these days go to http://www.cole2k.net
You can play DivX 5.xx using an installation of FFDShow, only:
There is absolutely no requirement to install the free DivX 5 codec, unless you’re intending to encode some video using it.
The free version of DivX 5 comes packed with Spyware and Ad-ware, it is not good. Avoid it.
> The free version of DivX 5 comes packed with Spyware and Ad-ware, it is not good. Avoid it.
This may have been true a long time ago, but is no longer true. I think DivXNetworks have made enough money to stop relying on spy/ad-ware for revenue.