S-Video Connections have been common to higher-end Video Tape Recorders (VCRs). They are even more common on DVD players and recorder players.
This connection is second in quality to that of VGA connections.The difference in quality between RCA/Composite (yellow ended unless Apple which designates the red end) and s-video is more pronounced the higher the resolution being projected.
S-Video Cable. These can be confused with extension cables for keyboards, mice, and other round end serial cables.(The extension cables are PS2 cables. PS2 Cables have 6 prongs plus the black keys which align the plug in the port. S-Video has 4 prongs plus the black alignment "keys".)
Video cameras, especially digital video, also have these s-video ports. More and more televisions are being built with this port.
Following this trend more recent notebook computers are equipped with these ports. Some computers have only an "S-Video" port. These can send the picture of what is on their monitors to another display or video recorder. Higher end laptop computers have both "S-video" Out and "S-Video in". With an "S-Video IN" the computer with the right software can capture video from a camera, dvd or vhs player.
The Advantages of S-Video:
1. More portable cable. VGA cables are much more bulky.
2. S-Video has more uses.
You could have a couple of these cables in your accessory bag and use one for computer-projector connection and another to hook a high end vcr, a dvd, or a video camera (for live feed) to your projector. Many late-model televisions, especially larger screen have these ports so that if a projector is not really needed, the presenter could (if there is an s-video port on the computer) run an s-video cable from the notebook to the television. VGA would have to be converted to S-Video to accomplish the same feat.
3. In more complex presentations, s-video is simpler to configure with a video switch between output devices (that is, what will generate the image to be fed to the projector; e.g. computer, dvd, vcr, camera, etc)
Disadvantages of S-Video:
1. Cable extensions are limited to 25 feet without the use of an amplifier to boost the signal.
2. Some notebooks and many middle to lower end vcrs do not have this port built in.
3. Like VGA, S-Video carries no audio. For one cable that carries both video and audio, look for 1394 / "Firewire."
4. Older televisions do not have this port.