Video Connectors Tutorial

Separated Video (S-Video)

S-Video provides better image quality than composite video. The composite video signal uses only two wires, one carrying the video signal and the other one being the ground. On S-Video, three wires are used: one for carrying the image in black-and-white, one for carrying the color information signal, and the third is the ground. Hence the name of this standard, separated video.

All current TV sets and video projectors have this connector, but you should use it only if your TV or video projector and the device you want to connect to it don’t offer a better connection option, such as component video, DVI or HDMI.

Figure 12: S-Video connector on a TV set

Figure 13: S-Video connector on a DVD player

Some older video cards have an S-Video output, as you can see in Figure 14. On video cards with video capture function (a.k.a. VIVO) or with component video outputs, this very same connector is also used for these functions. The standard S-Video connector has four pins. If the S-Video connector from your video card has more than four pins, that means your video card has component video or video capture functions. We’ll talk more about this on the next page.

Figure 14: S-Video connector on a video card

S-Video is the best way to connect your PC to an old analog TV set, provided your TV set and your video card don’t support component video (see next page). However, keep in mind that the image quality of CRT-based TV sets is far below any video monitor. There are two reasons. First, analog TVs work at 640×480 resolution (a.k.a. 480i or SDTV), lower than the most common screen resolutions nowadays. Second, analog TV sets work with interlaced scanning, while video monitors work with non-interlaced scanning (a.k.a. progressive scanning), which provides far better video quality. Therefore, for connecting PCs to TVs and video projectors, you should use the DVI or HDMI connectors, as we will explain later. (If your video projector doesn’t feature either of these connectors, then the option is to use the VGA connection, which is usually found on video projectors but not on TV sets.)

In Figure 15, we see the standard S-Video connector and cable. The S-Video signal can be transformed into composite video by using an adapter (shown in Figures 16 and 17). It is useful to connect a video source that only has S-Video output to a TV set that doesn’t have an S-Video input or vice versa.

Figure 15: S-Video connector and cable

Figure 16: S-Video to composite video adapter

Figure 17: This cable provides S-Video at one end and composite video at the other