S-Video uses four pins and offers a better picture than composite video. It is a good choice for older devices that don’t have HDMI or component video connections.
S-Video connectors are generally 4 pin mini-DIN plugs that require 75 ohm termination impedance. They are similar to those used on Apple Desktop Bus for Macintosh computers.
Luminance is the part of the video signal that carries the black and white elements of the picture. It also carries horizontal and vertical synchronization pulses. S-video uses separate signals for luminance and chrominance, which is an improvement over composite video. This allows for better color resolution than standard analog signals.
The luminance and chrominance signals are transmitted on separate lines in the S-Video connector. There are two different types of S-Video connectors: the standard 4-pin and the lockable S-video, which has a collar that can be pulled down to prevent accidental disconnection. The standard 4-pin connector is pin compatible with the standard mini-DIN plug that comes on many laptops and PCs.
The luma line is the one with the RCA male connectors, while the chroma line has the SCART female connector. It is not easy to find a cable that supports both of these connections, but if you’re willing to make your own, it’s relatively inexpensive to do so. You’ll need an S-video lead, an ordinary audio cable with RCA male connectors and a SCART cable (check the other post for more information on these). You may also want some heat shrinking tubing, wire strippers and soldering equipment. The DIN plugs used in S-Video are hollow and look like small tubes, which makes them easier to solder onto than solid pins.
The chrominance (C) component of the video signal is what gives the image its color. It is not transmitted separately from luminance, but rather is combined with the Y component to form a composite video signal. The Y signal contains values for brightness (luminescence) and the C signal decodes them into red, green, and blue values. The human visual system is less sensitive to changes in the position of color than to brightness, so the color information can be sampled at a lower rate.
S-Video uses separate wires to carry the luminance and chrominance signals, providing better quality than composite video. This is because the S-Video signal does not have to use the same bandwidth for both the Y and the C signals, as it does with composite video. This allows the Y signal to be low-pass filtered without dulling the image, which is not possible with the more common composite format.
The chroma signal is at a higher voltage level than the luma signal, and may require a resistor in series to reduce the voltage to a safe level for your device. A value of 330 ohms is commonly used. This will prevent the chroma signal from overpowering the luminance signal and producing a checkered pattern across the screen.
A standard analog video signal must pass through many steps and filters before it reaches its destination, which can cause the signal to lose quality. S-video separates the brightness and color information into two signals that travel over two wires, which helps to prevent this loss of data. This results in better image and color quality than composite video.
S-video also provides a better connection than composite video for audio. The separate audio cable means that you can use your existing stereo headphones with your new device, which eliminates the need for additional adapters. This is a big advantage for people who want to watch TV in their rooms without disturbing others with the sound from the television.
There are a few different types of S-video connectors, but the most common is the 4-pin mini DIN connector. This can be found on devices such as video cameras and PC video grabber cards. It is a very common plug and can be easily purchased from most electronics stores. There are also “combo” s-video jacks that combine other connection types such as RCA, RGB and YPbPR (all use the same pins), stereo analog audio and the Apple desktop bus used on Macintosh computers. The latter are not compatible with a standard four pin S-video plug and may only accept a seven-pin connector or have an extra three sockets that don’t carry any S-Video signals.