A clear understanding of today’s video signals

With the growth of home theatre, video cameras and the consumer electronics market many of today's computers and peripherals (especially LCDs) have multiple video input options available to them. Here is a clearer picture of what these signals represent.

Composite video, also referred to as baseband or RCA video, is the most common of all video signals.
A composite video signal consists of an analog waveform that conveys the image data in a conventional National Television Standards Committee (NTSC) television signal. Composite video contains chrominance (hue and saturation) and luminance (brightness) information, along with synchronization
and blanking pulses, all together in a single signal.

Composite video is the standard that connects almost all consumer video equipment through a phono-jack, also known as an RCA connector. In composite video, interference between the chrominance and luminance information is inevitable resulting in poor quality video when signals are weak. The cable has 3 jacks: yellow, white, and red. One jack sends the audio (left), the second the stereo (right), and the third the video, respectively.
The picture quality is decent but pales in comparison to S-Video

S-Video (Super-Video, Super-VHS) and sometimes referred to as Y/C Video was introduced in the 1980s and solved some of the problems that were inherent with composite video. S-Video provides better color separation and a much cleaner signal by keeping the transmitted luminance and chrominance video signals separated.

Today, S-Video signals are generally connected using 4-pin mini-DIN connectors using a 75 ohm termination impedance. S-Video provides for a high quality method of delivering a clean crisp video signal.

Component video improves the picture quality even more than S-Video. Component refers to video transmitted as three separate signals (subsignals if you prefer) to represent all colors. The first component video was RGB since the three signals represented pure red, pure green, and pure blue content respectively. Today, most video experts use the term "component video" as short for "analog component video" consisting of the three signals Y (luminance), Pr or R-Y, and Pb or B-Y. For NTSC or PAL (interlaced video formats) the Y signal is the same as that used to construct composite video or that found in S-Video.

The most common connection from DVD players is three RCA-type jacks.

(For a very technical explanation of color television and component video, seeTektronix's Web site.)