Thread Starter

Anand Sharma

Dear Listers,
Can anybody tell me what are the outputs S-Out, A-Out, and Composite video out available in the modern day video cards meant for. Thanks in advance.

Rich Anderson

I hate to disagree, but I wish to clear this up.

S Video: Uses a connector similar to a PS/2 style keyboard with a multi-conductor cable. It uses separate wires for the chroma (color) signal and the luminance (brightness) signals. These 2 signals (being separate) give a much better picture than "composite video" (see below). It is found on high-end video equipment, typically on S-
VHS video equipment and the new High Definition TV's. Don't confuse the S Video with S-VHS, they are 2 different things. The S in S-VHS stands for "Super". (S-VHS has more horizontal scan lines than regular VHS). I believe/but I am NOT positive that the "S" in S Video stands for "Separate". S Video does NOT carry audio.

Composite Video: This is a signal that I like to call "raw video" it uses an "RCA" connector. This is the same connector/signal that a monitor TV and a consumer VCR have. It uses RCA jacks that are called video out/video in. It is normally colored yellow. It is called composite video because both the chroma and luminance information are carried on a signal wire. Composite Video does
NOT carry audio.

A Out: If this jack is an RCA connector, and it is colored white or red, then I would suspect it would be an audio signal. If you have both white and red, then white is the left, and red is the right channel. If you only have the red, then it is a mono signal.

So, a typical home stereo VCR has 3 RCA connectors on it for Video In, and 3 RCA connectors on it for Video Out. The yellow
one is Composite Video. The red and white are the audio.

As far as the S Video connector... don't worry about it. You won't be able to use it unless you have some "ProSumer" equipment.

Rich Anderson
Automation Controls Programmer
Anamax Group

Greg Meister


The S-Out is S-Video, a high quality video output that is common on high-end TVs, VCR's, Laserdisc players, DVD players and video cameras. It uses a version of the mini-DIN connector.

The A-Out is your analog output used on common VGA video monitors. This is a high-density 15-pin D-shell connector.

The composite output uses an RCA-type connector and conforms to the NTSC and/or PAL composite video standards. The NTSC standard is used in North America, the PAL standard is used pretty much everywhere else. This type of interface is common on most TVs, VCR's and Laserdisc players and video cameras (both low and high-end products).

These three connectors simply allow you to output your computers' video output to a wide variety of displays and recorders, without the use of
external 'black boxes' to convert the signal to the different formats. If I were to put the three modes in order of video output quality it would be A-Out, S-Out, composite.

Contrary to one of the responses to your question, there is no audio output on any of these connectors.

I hope this helps.

Greg Meister
NAC Northern Automation Controls Inc.
[email protected]