WMV HD stands for Windows Media Video High-Definition. Just what makes high definition video different? 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 480/576 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. http://www.microsoft.com/windows/win...uthdvideo.aspx