S-Video carries a standard definition only video signal on a 4 or 7 pin mini-DIN interconnect. S-Video carries two analog video signals; luminance and chrominance. Luminance (Y) provides the picture’s intensity data while chrominance (C) provides the color information. Hence, S-Video is sometimes called Y/C. The two video signals allow S-Video to have a clearer picture than composite’s single video signal, but not as clear as component’s three video signals.
The composite signal is capable of transmitting standard definition video only, and is frequently seen using the RCA interconnect. Composite video combines Luminance (Y) and Chrominance (C) into one analog video signal. Luminance (Y) provides the picture’s intensity data while chrominance (C) provides the color information. The composite video is then encoded into a standard format called NTSC in America and PAL in Europe. Combining the video signals into one reduces the quality of video when compared to S-Video’s two signals or component’s three signals.
Unknown by most Americans, SCART is a European–only interconnect that brings RGB, composite, S-Video, and analog audio signals all into one connector. Before SCART, many countries had their own specific video or audio interconnect. SCART was developed to bring a video and audio interconnect standard across Europe. Technically, it is possible for SCART to output high definition video using the RGB video signals, or by outputting a component video signal using the RGB pins. However, SCART is designed to be a standard definition only interface. Digital surround sound is also not possible since SCART carries analog signals only.