Video Formats

• A television signal presents a synchronizing signal, along with brightness and color information to a viewing screen. The format of a television signal details how those signals are presented to the screen. The most common formats include composite video, which mixes all the information onto a single cable, S-video which uses two signals, and component video which uses three.
  
  

S-Video

• In the S-video format, the synchronization and brightness information travel on one cable labeled "Y." The color information travels on another cable labeled "C." Separating the two -- the meaning of the "S" -- allows more information to be presented to the screen with less chance of interference caused by mixing signals. S-video creates a higher quality picture than composite video, but not as high a quality as component video.
  
  

Four-Pin S-Video Connector

• A four-pin S-video connector transports the Y and C signals from one component to another. When viewing an S-video connector with the alignment key pointed up, the bottom-right pin is number one, and the pins then count clockwise. Pins one and two carry the grounds for the two signals. Pin three carries the Y or luminance signal and pin four carries the C or chrominance signal.
  
  

Seven-Pin S-Video Connector

• A seven-pin connector carries the same signals on pins one through four, but may have other signals on the remaining three pins, depending on the application. Video cards for computers use the same seven-pin connector. But many people mistakenly label this connector S-video. In reality, it can be programmed to carry any other video format and not carry S-video at all. For the exact connections to one of these connectors, you must consult the manual for your computer or video card. See various pinouts at WeetHet and Clear Cloud.