The luminance signal and modulated chrominance subcarrier information are carried on separate signal/ground pairs. The luminance signal is effectively a black-and-white television signal with the timing of a colour composite video signal. Because the luminance signal is carried on a separate wire, it does not need to be low-pass filtered to prevent crosstalk between high-frequency luminance information and the colour subcarrier.
This allows a higher bandwidth to be used for the luminance information, and also eliminates the colour crosstalk problem.
The luminance performance of S-Video is similar to analog component video, but the chrominance performance retains most of the other defects of composite video, apart from the crosstalk problem.
S-Video signals are generally connected using 4-pin mini-DIN connectors using a 75 ohm termination impedance. The pins in the connectors bend easily, hence care must be taken when plugging the cables in--else a pin is likely to bend, causing the loss of color, corruption of the signal, or complete loss of the signal.
S-Video is commonly used on consumer DVD players, VTRss, and modern game consoles. It is also available on some professional equipment and computer video capture and playback cards.
See also
This entry contains some text from FOLDOC, used by permission.