Traditional television sets have a 4:3 aspect ratio. Widescreen television sets have a 16:9 aspect ratio.
Based upon pixel resolution, color resolution, color detail, black level reproduction and a virtual lack of color noise, the DVD picture is nearly 3 times better than conventional VHS.
DVD is a format that will provide significant picture quality advantages when connected to your television set via the S-Video connectors. Your DVD player must have S-Video output to take advantage of this capability. Remember that the color detail signal is so rich, you will find that you do not need to turn your sharpness control up when watching DVD. In fact, in many television sets, you will optimize picture quality by turning the sharpness control off!
DVD is mastered as CCIR601 4:2:2 digital component video and utilizes 100% MPEG-2 data reduction. The digital component video signal of DVD has the capability to rival the best studio masters.
Video : Aspect ratio explained