With Vista Codec Package installed you will be able to use any media player (limited only by the players capabilities) to play DVD's, movies and video clips of any format. Streaming video (real and quicktime) is supported in web browsers. The Vista Codec Package is compatible with all versions of Windows XP. MKV playback is fully supported. Vista Codec Package does not contain a media player and it does not associate File -types. With this package installed you will be able to use any media player, limited only by the players' capabilities, to play all movies and video clips. Streaming video is supported in several formats in all popular web browsers. Users of VCP have the ability to choose what is installed and where to install it using the public redistributable. After installation you can select to remove specific portions without removing the entire package. You can also re-add the removed items at any time.