S-Video and Audio Pinout
S-Video and audio leads are a popular way to connect devices to TVs. They are sometimes also called ‘S-VHS’ leads.
These lead with a 4 pin mini DIN connector and have a pair of wires, Y for luminance (brightness) and C for chrominance.
These cables are an improvement over basic composite video but have been supplanted by newer digital interfaces like HDMI. However, some older equipment still has S-Video output ports.
4-Pin
This type of lead (also known as an S-Video or S-VHS lead) is normally used to connect video devices such as camcorders, PC Video Grabber cards or DVD players to televisions or other video equipment. It carries two separate video signals called Luminance and Chrominance which together define the brightness and colour of an image.
The Luminance signal also carries horizontal and vertical sync pulses which are separate from the colour information. However, unlike component video, which carries the separate luminance and chrominance signals on dedicated frequencies, S-Video must combine these onto one shared subcarrier frequency of either 3.58 megahertz for NTSC or 4.43 megahertz for PAL. This severely limits the color resolution compared to component video.
Some older VCRs have SCART connectors which can be connected to an S-Video cable, but not all televisions which have these are wired to accept the signal. This is because they were designed to use the same pins for RGB, causing them to conflict with S-Video.
7-Pin
In addition to the four pins used for S-Video, some older graphics cards use a 7-pin mini-DIN connector that is incompatible with standard 4-pin S-Video cables. This is most often seen on older JVC S-VHS players and some SCART connections used in Europe until HDMI became more popular.
In this case the first three pins of the seven-pin connector are the same as the four pin S-Video and can carry composite, RGB or YPBPR signals. However, the last two pins of the connector are not standardized and can vary between different manufacturers.
These non-standard seven pin mini-DIN connectors are also commonly found on ATI Radeon video cards and some Dell laptops. Our 7-Pin to 4-Pin S-Video Adapter will fit these connectors and convert them to standard 4 pin s-video cables. Note that this adapter will only work with computers that can output s-video and not composite or digital audio (S/PDIF). Please check your laptop specifications before ordering.
9-Pin
Many older computers use a 9-pin connector for their video displays. These are usually called DB-9 connectors, although they are more commonly known as a “15-pin D-sub” or even just a ‘d-sub’ connector. These are often found on monitors that used the VGA interface, which is now obsolete and has been replaced by SVGA.
While this connector is used for video signals, it can also be found on other types of devices like serial ports, Atari-style digital joysticks and more. The pins are arranged in a single row, and they can be either male or female.
The VGA [Video Graphics Adapter] interface was introduced in 1987, and it was followed by Super VGA (SVGA) in 1990. The VGA interface sends digital signals to the monitor, while later standards like SVGA send analog signals. This is the reason that these earlier interfaces cannot display all SVGA modes on their screens. The following table lists the corresponding signals on the DB-9 pin connector.
Composite Video
Composite video is a single-channel analog signal that combines the luminance (brightness) and chrominance signals on one cable. It can be identified by a yellow cable and a red, white and blue connector, or the letters CVBS (color, video, blanking, sync). Audio is transmitted over a separate connection.
The luminance and chrominance signals are combined to save bandwidth. Luminance is encoded as a linear combination of line and frame synchronization pulses, while the chrominance signal is modulated on a subcarrier. This process is distinct from component video, which splits the signals into individual channels for better quality.
Composite connections can be found on older televisions and VCRs, as well as some newer devices that support only this format. The cable is typically paired with a stereo analog audio connector, which will allow you to transmit sound along with the video signal. Although it is capable of delivering strong signals, composite video can suffer from a lack of resolution and clarity when compared to S-Video or component video.