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When I got my Sega Saturn way back, it came with a video cable that is S-VIDEO in the Saturn end and SCART in the TV end (no adapter). It has always given me very crisp and nice picture on all the TVs I have used it on, better than the other consoles such as SNES/PS/N64, which all end with RCA (red/white/yellow) cables that go into a SCART adapter and then into the TV.

My understanding is that "S-VIDEO" is somewhere in between "composite" (RCA or white/red/yellow) and "component" (RGB) cables in terms of signal quality.

However, modern TVs no longer even have one single SCART connector, so I could not even connect my Saturn to the current TV to compare it with the following.

So I recently bought a different video cable for my Saturn, which (of course) has the same S-VIDEO connector in the Saturn end (it's the only way the Saturn outputs video), but instead of SCART in the TV end, it has just the plain old RCA cables (yellow, white, red), just like my other consoles. Which can either be plugged directly into the TV or into a SCART adapter which is then plugged into the TV.

So that must mean that the new cable has a composite video signal, right? In other words, more "bleedy" than the "pure" S-VIDEO signal with the old cable, which is "S-VIDEO" all the way?

I wish I had a way to test this, take photos and compare myself to be sure, but the next best thing is to ask here. I'm 99% sure I've got it right, but who knows? Maybe I just imagined the "crisp picture" that the Saturn always seemed to produce with the old cable, and maybe it's just converted to a plain old "RCA" signal inside of it?

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  • It's actually a 10-pin mini-DIN on the Saturn side, and it carries Y/V, composite, RGBS, and audio L/R.
    – snips-n-snails
    Commented Jul 17, 2021 at 20:08
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    Is it really connceted as S-Video on Saturn end, or do you mean the mini-DIN connector which has all kinds of video outputs? SCART supports composite, RGB, and later TVs also support S-Video. It's possible you had a RGB cable.
    – Justme
    Commented Jul 17, 2021 at 20:28
  • Well, I thought it was S-VIDEO in the Saturn end, but now I'm anything but sure.
    – Terreon
    Commented Jul 17, 2021 at 20:39
  • @Terreon Anyway, if there is RCA connector at the TV end, it will definitely be composite, and it has the worst quality of what is available. So, in the likely case that the SCART did not use composite, but either RGB or S-Video, the SCART was better. In the unlikely case that SCART did use composite, then the quality would be exactly identical. Do note that only the yellow RCA carries video. The white and red RCA are just for left and right audio.
    – Justme
    Commented Jul 17, 2021 at 20:49
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    As snips mentions there is RGBS on the Saturn and with SCART and most TV will have used the RGBS, which of course gives the best transmission. Then again, the cable may carry everything there is, so it't up to the TV configuration. Most TV do prefer RGB over S-Video over Composite, depending on whats present. If the old TV is still around, it might be possible to look up in some configuration menue which source is used.
    – Raffzahn
    Commented Jul 17, 2021 at 23:18

2 Answers 2

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So let's sort out the way all those signals work.

  • RGB uses three lines, R for the "red" signal, G for the "green" signal, and B for the blue signal. Each signal's amplitude directly corresponds to the intensity of the electron beam used by the TV to excite the corresponding phosphor for this color.

  • S-Video uses two lines, Y for luminance (intensity), and C for chrominance (color). To get all colors with a single line, color is encoded as phase and amplitate onto a color carrier frequency.

  • Composite uses a single line, with the same encoding for color as S-Video, and the luminance mixed it in the frequency range below the color carrier. This means the luminance is bandwidth limited, making it less "crisp" than the others. (This is more or less the signal that you got out of a terrestrial broadcast).

For red/white/yellow RCA connections, yellow is usually the composite signal and red/white are for the stereo audio signal. (Though there are also RCA connections for RGB and a fourth system called "component", but those have differently colored plugs).

Now SCART supports all of these (composite, S-Video, RGB, and component). That's why "I have a SCART cable" alone really doesn't tell you anything about what system is used.

That said, if you had an S-Video to SCART cable, it likely passed through both the C and the Y signal, giving you the crisp picture.

While if you put an red/white/yellow RCA cable into a SCART adapter, the yellow composite signal stays the composite signal, giving you a picture that's less crisp.

And a cable with S-Video on the one end and red/white/yellow RCA on the other end will downmix the C and Y signal into a single composite signal (that can easily be done with a capacity), again giving you a picture that's less crisp.

So if you want a crisp picture from an S-Video signal with a modern LCD TV, you either need something that samples the analog S-Video signal directly (without converting it to composite first), and then converts it to HDMI; or you need a TV that has these ways of conversions built-in (I have one of those). Still, this picture will be different compared to the picture you see on an analog TV, because of the analog/digital conversion that needs to happen.

So the only way to give you the original experience is to somehow get your hands on an analog TV (or monitor).

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    Good answer, but it's worth double checking the OP's info. The Sega Saturn video port pinout looks kinda like S-Video, but it's 11 pins with most things SCART has: L/R audio, composite, S-Video, RGB and sync: gamesx.com/wiki/doku.php?id=av:saturnav
    – Nick Westgate
    Commented Jul 18, 2021 at 7:38
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    @NickWestgate That''s correct - So, the Saturn's video port in essence is very close to SCART. Video quality depends meinly on how the cable is wired - I find it, however, important to mention that S-Video is, in principle, closer to composite than to RGB because composite just overlays the Chroma and Luma signals of S-Video into one.
    – tofro
    Commented Jul 18, 2021 at 7:53
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    @tofro: I should've made my point clearer. I suppose this answer is trying to address the (title) question posed by the OP, but in actuality he was almost certainly comparing his experience with (analogue) RGB to composite. The entire S-Video topic is his misinterpretation of the Saturn output port. The question is ill-posed, really.
    – Nick Westgate
    Commented Jul 18, 2021 at 8:30
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    It may well be that the original cable was passing all 3 signals from the Saturn to the TV and the TV was selecting the best, e.g. RGB.
    – Mark Williams
    Commented Jul 18, 2021 at 10:34
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    @Justme: I'm just another oldish software guy, but I've heard the low-pass filter stuff from older hardware guys over the years. Here's one source: "One of the initial separation techniques used was the Low Pass/High Pass Filter technique to separate the luminance and chrominance signals from the composite video signal. The was the simplest and least costly to implement when color TV was first available."
    – Nick Westgate
    Commented Jul 19, 2021 at 1:11
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If you can get a converter to render either S-video or SCART to component or HDMI, those should give the best possible quality. Converting S-video to composite would be a definite downgrade, though the severity would depend upon the type of content being displayed and the system's resolution.

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