The process that horizontally squeezes a widescreen (16:9) image so that it can be stored into a standard 4:3 aspect ratio DVD image frame. When played back on a 4:3 television, the DVD player usually restores the correct aspect ratio and generates black bars at the top and bottom of the frame. If the DVD player is set up incorrectly, the picture may be distorted, making objects appear thin and tall.
If content is viewed on a 16:9 display, the TV restores the anamorphic widescreen image to its original proportions. Non-anamorphic video played on the same television has not only the black bars at the top and bottom, but grey bars on the left and right because the video signal is more square than the television screen.