It comes down to video resolution. The video most of us are used to seeing on our TVs today, called "standard definition," has at most 480 visible lines of detail, whereas "high definition" video has as many as 1,080. High definition video looks sharper and clearer than regular video, especially on big-screen displays. It actually comes in two different resolutions, called 1080p and 720p.

Most of the talk around high definition video has been associated with HDTV. But you can get high definition video today on a high-definition capable Windows XP–based computer. By simply connecting your computer to a high definition display, you can be watching movies in amazing quality, up to 6 times higher than that of today's DVDs!

The same compression technology that makes Windows Media the best format for streaming digital audio and video is being used to bring a whole new level of high definition entertainment to consumers through DVDs and downloadable online content. Today, movie studios are distributing Windows Media High Definition Video (WMV HD) movies on companion DVD-ROMs that are packaged along with the standard definition DVD-ROMs.

To take advantage of WMV HD, you might have to upgrade your computer to a system capable of playing back high definition video.

From Microsoft