What Is S-Video?

Standard-definition S-video is declining in popularity

Close-up of s-video cable
Evan-Amos / Wikimedia Commons / Public Domain

S-video (short for Super-video) is an older type of video signal that's transmitted in varying electrical signals over wires to represent the original video. Newer video cables like HDMI transmit digital video signals in the form of numbers representing the original video signal.

The benefit of digital video is that the signal doesn't degrade from source to destination. It's also capable of transmitting much higher resolution video.

However, there are still electronics today that have S-video ports, so understanding the technology and how to use it can be very useful for troubleshooting problems you may have. For example, if your TV's S-video input has trouble finding a signal.

If you can afford it, upgrading your electronics to newer models capable of sending and receiving digital video will greatly enhance your video. This is prefered over trying to use older s-Video cables, since you'll be able to take full advantage of high definition technology built into modern television sets and computer monitors.

About S-Video

Closeup of S-video cable with audio cables included.
riceteck at morguefile.com

S-video technology, where the analog video signal in its original form over wires, it can only transmit standard definition video, which is a resolution of 480i or 576i.

S-video is an improvement over composite video, which carries all the video data (including both brightness and color information) in one signal over one wire. S-video carries brightness and color information as two separate signals, over two wires.

Because of this separation, video transferred by S-video is higher quality than that of composite video.

S-video has a variety of uses, including connecting computers, DVD players, video consoles, video cameras and VCRs to TVs.

The S-Video Port

A photo of a video card with an S-video port.

S video ports can be either 4, 7, or 9 pin. You can recognize them on your computer or TV because they're a round port with multiple holes and a slightly flat bottom.

Like composite video, which is typically the yellow cable in a three-plug wire setup, the S-video cable only carries the video signal. So, composite audio cables are still required (the red and white composite wires).

Using the S-video instead of the composite wire will provide much better color resolution.

Composite (yellow wire) video technology was based upon original television technology, where color was made possible by transmitting color information over a single wire. s-Video was an attempt to improve color in the signal by transmitting color information over a seperate wire.

How S-Video Works

How does S-video work?

The S-video cable transmits video via two synchronized signal and ground pairs, named Y and C.

  • Y is the luma signal, which carries the luminance. This is the brightness or black-and-white elements of the video. It also includes horizontal and vertical synchronization pulses.
  • C is the chroma signal, which carries the chrominance. This is the color portion of the picture. This signal includes both the saturation and hue elements of the video.

S-video is also known as 'component video' and 'Y/C' video.

If both your output device (computer, DVD player, or game console) and your input device (television) has an S-video port, you're in luck. All you need is an S-video cable with the correct number of holes at each end, and you can enjoy higher-quality video.

S-Video Not Finding a Signal

Hand holding remote control
ImFabio / Getty Images

To use S-video to connect audiovisual equipment, both devices must support S-video and have S-video ports or jacks. An S-video cable connects the two devices.

Even when you think you've connected everything correctly, your TV may still not be able to find the S-video signal.

The following is a checklist of some things you can try to resolve this issue.

  • Press Source or Input on your TV remote and make sure to select either composite or component input.
  • Double check the cable end and the port you've plugged in into. Are the number of holes the same? If not, you can purchase an adapter for that end.
  • Make sure your source device (computer or game console) is sending its video out through the S-video output port. Double check video settings.
  • If the device you're trying to connect doesn't have an S-video port, you can usually find an adapter that will convert composite video, digital ports, DisplayPort, or HDMI into an S-video cable that you can plug into your TV. You can also find adapters that convert from an S-video cable to HDMI or RGB input you can plug into your TV or computer monitor.

With the advent of HDMI and other digital video solutions, fewer electronics manufacturers are shipping devices with s-Video ports.

But until they're all gone, there are plenty of adapter and cable solutions to help you hook up older devices to new ones.