VGA vs S-video - quality differences?

Hello,

S-Video is basically Composite Video. That is the same video signal used by just about all your lower-end and older consumer electronics.

It is good. At least when you are talking about low-resolution video that does not need to be crisp and sharp.

This is fine for VHS tapes, and even some video game systems.

But, if you want sharp, crisp, defined, and high-resolution images, then you should definitely stay away from S-Video. Go with Digital or VGA.

There really is no comparison. S-Video is the bottom of the line. It's slightly better than plain composite. But, not much.

I hope this helps.

VGA may give better video quality than S-Video since the color bandwidth limitations will be gone.

The previous poster stated that S-Video was basically composite video, but there is a pretty good quality jump from composite to S-video because the luminance and chrominance aren't mixed together, so you don't get the annoying "dot crawl" and the sacrifice of high-frequency detail in order to get the color in the signal.

VGA should give a picture quality as good as component video, freeing you from the color bandwidth limitations of the lower forms of video connections. This, however, assumes, that both the computer does a good job of translating the source into VGA, and the TV does a good job of processing the VGA input.


Mac Mini Intel Dual Core 1.66GHz 2GB, MacBook Intel Dual Core 1.83GHz 1GB Mac OS X (10.4.7)

Hello,

Thanks both of you.

You're welcome.

I will look at the cost of running the VGA cable
through the wall, maybe I can pull it through using
one of the existing cables.

Keep in-mind the VGA signals can only span short distances without a signal booster / amplifier. I think the safe range is 10 feet. Beyond that, perhaps 15-feet total before the drop in quality really starts to suffer terribly.

I've never pushed it more than about 10 feet myself. And, I could see minor degradation at that point.

They do have a variety of means to move VGA signals much further. Some are just boosters, others are VGA to Ethernet solutions like:

http://www.networktechinc.com/vga-extender.html

I've been checking out the progressive vs interlaced
issue too - it appears that s-video can only be
interlaced (?).

I do believe you are correct that S-Video is Interlaced.

I assume that the Mac Mini will read a DVD,
de-interlace it since computer monitors are never
interlaced, then re-interlace it when converting to
S-video. Is that right? If so, that must affect the
quality!?

That sounds perfectly logical to me.

You might also find this short discussion of some use:

http://www.diyaudio.com/forums/showthread/t-37537.html

And, if you move up to the root level (main level) of the forum in that group, they may have some other helpful information as you browse around.

I hope this helps.

Let us know if you have other questions.


P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.

Yes, S-Video is interlaced. S-Video will allow a high bandwidth luminance component (4.2 MHz or higher, depending on what your device will put out), but the chrominance will probably be limited to 600 KHz.

If your display is only 640 by 480, you won't be able to display more than the equivalent of 4.23 MHz NTSC analog video bandwidth anyway. The advantage of the VGA connection will allow your color bandwidth to equal your luminance bandwidth if your device is capable of producing that quality of a signal (such as for a computer display, although no consumer standard-definition video sources have a color bandwidth equal to their luminance bandwidth). Originally, the I component was to be 1.5 MHz and the Q component was to be 600 KHz, but usually, both are 600 KHz. The color shading from an NTSC video source is only capable of changing at a much slower rate horizontallly than the luminance (one seventh for a standard broadcast). For DVDs, the color resolution is half the luminance resolution in BOTH the horizontal and vertical directions, but that's still quite as bit more color information than in a standard braodcast, which is what makes DVD look so good compared to them (that and the lack of time-base error).

As mentioned before, the VGA at 640 by 480 should be progressive, so your TV won't have to convert from interlaced to progressive. If this conversion is done in the digital domain before conversation to analog, the results can be considerably better than a TV doing it by resampling the analog signal and converting it.