What does "anamorphic" widescreen mean?

The DVD format is specially designed to support widescreen displays. Widescreen 16:9 video can be stored on the DVD disc in anamorphic form, meaning the picture is squeezed horizontally to fit the standard 4:3 rectangle, then unsqueezed during playback. This anamorphic squeezing results in less of the picture being wasted on the black letterbox mattes. DVD has a frame size designed for 1.33 display, so the video still has to be made to fit, but because it's only squeezed horizontally, 33% more pixels (25% of the total pixels in a video frame) are used to store active picture instead of black. Anamorphic video is best displayed on widescreen equipment, which stretches the video back out to its original width. Anamorphic video can be converted by the player for display on standard 4:3 TVs in letterbox or pan & scan form. If anamorphic video is shown unchanged on a standard 4:3 display, people will look tall and skinny as if they have been on a crash diet. The setup options of DVD ...  more