What is Alpha Blending?
DVDs allow up to 32 channels of graphic overlays, called “subpictures,” to display additional user information (subtitles, captions, menus, etc.) over video. Each subpicture contains up to 16 simultaneous colors and each color has up to 14 levels of transparency, plus opaque. Alpha blending allows the graphic chip to set a level of transparency for each subpicture pixel as it was intended by the content producer of the DVD. The use of Alpha blending allows subpictures to display the same as on dedicated DVD players. Some graphics chips allow Alpha blending to occur in hardware; however, WinDVD can also use advanced software alpha blending to create the clearest, smoothest subpictures and highlights available.
