OT - S-Video lookin great

Stonefield wrote on 7/25/2006, 5:52 PM
I'm sure this will be funny to most of you. You all know how far behind the game I am with my little one chip Elura and very meager equipment that I have. So when I finally bought a second hand Sony Trinitron I was looking forward to the fact that I can finally use the S-Video connection instead of my RCA plugs.

I must say I love how much better it looks and it made me curious....what is S-Video doing to make a better signal that the yellow RCA connection isn't doing ?

Stan

Comments

johnmeyer wrote on 7/25/2006, 6:06 PM
The chroma and the luma (color and brightness) are on separate wires, instead of being combined together. The difference is seldom startling, and sometimes is completely nil, depending on whether the video source has stored the two signals separately or not, and also on whether the video source's "comb filter" (if it has one) does a better job of separating the signals than does your TV set.

Wikipedia has a nice short article.

I pretty much gave up worrying about S-Video a long time ago after doing extensive A/B tests. On some source material that was very sharp and had people wearing bright red clothing (the part of the composite signal that is toughest to separate), I was able to notice a small difference around the edges.

All that said, if you have S-video on both your source and your recorder, use it.

bakerbud9 wrote on 7/25/2006, 6:12 PM
S-Video separates the chroma (color) from the luminance (black-and-white)... it transmits them over separate wires. The yellow RCA plug is a "composite" video source, that is, the chroma and luminance are mixed together into one signal and sent over a single wire.

RGB-component video is even another step-up from S-Video, because RGB-component further separates the chroma signal into red and blue and transmits them on separate wires, for a total of three wires: red, blue and luminance (green).
fldave wrote on 7/25/2006, 6:25 PM
Much cleaner signal from my old DISH satellite receiver to my old 53" Sony TV. Much cleaner.

Without doing research (from my faulty memory) S-video is about 450-500 lines while RCA composite is about 250 (???)

On other matters, they now have this wonderful new technology that makes a pot of coffee at the exact time you tell it to, and this other gizmo that allows people calling you leave a voice recording if you can't pick up the phone in time:)
GlennChan wrote on 7/25/2006, 6:51 PM
The composite connection is prone to problems where luma information gets confused with chroma, and vice versa. You get false color where there is fine detail, moire patterns, and/or "hanging" dots.
riredale wrote on 7/25/2006, 7:29 PM
My dad loves his "WebTV" box that we bought him nearly a decade ago. It's a simple little box that uses a TV as the monitor for web pages and email. It does surprisingly well, considering the fundamental limitations.

It makes a HUGE difference whether the box is connected to the TV via composite or S-Video.

In the NTSC system, chroma information is inserted into the luminance channel in a way that an exotic, X-Y-Z decoder can completely separate at the receiver end (Z being the time axis). The problem is that nearly all TVs have much simpler decoders, which create a host of artifacts. On my dad's TV the most obvious artifact was the "crawly dots" around the edges of colored objects.
farss wrote on 7/25/2006, 7:47 PM
One very big trap with S-Video can be the quality of the S-Video cable itself. We've had one occasion when the signal coming out of the S-Video looked worse (like where have all the colors gone?) than the composite feed.
Turns out a lot of S-Video cable really cannot handle the 6+ MHz bandwidth needed. Some of them are labelled "for monitoring only", what that means exactly I'll never know, "Don't use for anything" would seem appropriate.
My only gripe with S-Video apart from the quality of the cables is that PIA connector.
Of course if you've got the capability component is the way to go, sure as heck makes a world of difference coming off DVB.

Bob.