Starting with Windows 98, Microsoft have bundled a DVD Navigation Player on the Windows CD.
This player is not an real MPEG2 decoder as most players are, it's only a front end for use with
pre-installed DirectShow Audio/Video filters.
Microsoft didn't really bother with any fancy features, or even file playback. The player is just
a very simple navigation control, probably used as a sample code for creation of DVD Players under
Since this is only a front-end player, there it does not come with it's own Audio/Video decoding filters
and must rely on pre-installed (and compatible) filters. Not all actual DVD Players come with compatible
filters, and even those that do, don't always play at their best when using the built-in windows player.
Basically, if you are serious about DVD Playback, you should get a real decoder such as PowerDVD or WinDVD.