S-Video connector

The S-video connectors/cables carry video using two synchronized signals, Y and C, and a ground pair.

Y is the luma signal that carries the brightness or black and white of the picture, including the sync pulses.

C is the color signal that carries the chromaticity – or coloring – of the picture. This signal contains two color difference components.

The luminance signal carries horizontal and vertical sync pulses in the same way as the composite video signal.

S-Video connector

In composite video, signals coexist at different frequencies. To achieve this, the luminance signal must be low-pass filtered to dull the image. Because S-Video shields the two as separate signals, such harmful low-pass filtering for brightness is unnecessary, although the chrominance signal still has limited bandwidth relative to component video.