Were composite video colors that bad, in practice?

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#15

Gemini:

When connecting a PAL Super Nintendo (SNES) to an American (NTSC) television, it is very common to get a washed-out or too-bright image, or sometimes no color at all

. This is due to the fundamental differences in how PAL and NTSC consoles and video cables process and transmit analog color signals.

The technical reason for the washed-out colors

The cause of the washed-out or overly bright image is an impedance mismatch between the console and the cable:

  • PAL SNES consoles are designed to work with a cable that has a specific 75-ohm load resistor on the video signal line.
  • NTSC SNES consoles and cables do not require or include this resistor, as the impedance is handled differently by the console and TV.
  • When you use a standard NTSC cable with a PAL console, the missing resistor causes the video signal’s voltage to be roughly twice the standard level. This overdriven signal results in a bright, washed-out, and desaturated picture on your TV
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#16

Oh, didn’t know about that. But in the video he is presumably also using a PAL TV.

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#17

Yeah and I think RGB would be washed out too if this was the problem. Maybe not if he was using some weird custom PAL to NTSC cable :stuck_out_tongue:

So yeah, I don’t know what’s going on.

#18

There’s a couple of other videos on his channel which are differently captured. I’ve been actually meaning to open a thread sometime where we can collect channels that capture from real hardware.

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#19

I think this is it. Some TVs may have had less aggressive comb filters or notch filters, so you’d have more artifacts but less desaturation.

More aggressive filtering: sharper, less artifacts, less saturated

This also explains the look of composite video on PVMs that lack a comb filter: perfectly well saturated, but all of the artifacts are present, and chroma smeared even though local (edge) contrast is sharp, due to the excellent sharpening circuit.

The chroma-smeared but sharp look is only seen on high-end displays without comb filters. These are meant to display the entire signal clearly, warts and all, for production purposes.

#20

that will be a nice thing! not only channels but also images (there was Calling all CRT owners: photos please! but it kinda random, I think it need to add index in OP to every post with the TV type and cables)

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#21

I believe they were referring to the filters inside the SNES, not inside the TV, since the TV has settings that undo any change from the filter. If those settings are wrong while watching TV, the user can fix it, but they won’t know whether their games look right or not, right?

This makes me realize part of the reason why some consoles other than SNES do a band pass on modulated chroma, instead of lowpassing before modulating. It ensures that the same change is done both on the reference colorburst and on the actual chroma information. The TV would then be able to correct for the exact right amplitude. When I used my Dazzle DVC100, OBS let me turn chroma AGC on or off. My 1985 Toshiba Blackstripe has a button that seems to toggle this too, but I’m not entirely sure if that’s what this is.

That brings up another problem of keeping the chroma signal at a certain nonstandard amplitude factor, which causes the luma and chroma artifacts to scale inverse-proportionally.

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#22

I’ll defend use of RGB/Component/S-video for PS2/Gamecube- I can think of very few games that used dithering on either system. Both could do transparencies and had no problem displaying a lot of colors simultaneously, etc.

Everything else, use composite to be on the safe side of seeing what the artists intended.

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#23

This makes sense, but the s-video (aka Y/C) signal shouldn’t need the same aggressive filtering required to separate the luma from the chroma in composite and RF, since they’re already separated, right? By that logic, it should have similar saturation to RGB, right?

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#24

Yep! Good point. I have no idea, lol. Maybe there is no NTSC color correction on these late model Wegas? Or it’s less aggressive?

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#25

I have a PAL PS2 and it still has the factory composite cable. Most TVs like 95% would accept either composite RCA or composite via scart. I’ve seen very few having s-video in PAL region (But there were cheap adapters that plug to scart and had an s-video reception). Scart was almost always there though.

That being said, s-video was a great alternative to RGB, looks fantastic from what I’ve seen.

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#26

S-Video is mostly a feature of bigger TVs (over 21") in PAL regions, and then in later years probably mostly incorporated into a second SCART port instead of a separate input.

Nintendo’s official connect options for PAL stand a bit out, because they are so mixed. SNES had apparently only official RF/Composite cables. Curiously, there was an official RGB cable for Japan…

N64 does output S-Video but no RGB.

Cube and Wii + Wii U don’t output S-Video.

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#27

Check it out here:

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#28

I wonder if all of the connections in that video were adjusted the same. The RGB one looks darker, even in gray values. If the brightness or contrast was set differently, that could also affect the look (especially after it’s been captured by a camera). It’s also possible that the SNES has different output levels for RGB.

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#29

SNES RGB definitely looks very different from the other outputs. The greens in particular are eye-searingly bright. I thought there was something with my Framemeister the first time I plugged it up over RGB lol

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#30

The colors are basically the same with this guy’s RGB mod on his crt - this is what we expected. Localized, blur-related desaturation. Not totally different colors. It’s mostly a difference in sharpness.

Source (https://m.youtube.com/watch?v=r5SXXBANvhk)

#31

Were composite video colors that bad, in practice?

Not by a long shot! Especially on my Commodore 1702 on NES, SNES, TurboGrafx16 or TurboDuo.

Which is why my presets look the way they look.

It wasn’t bad on many other contemporary TVs of the era I used either, for example from Sharp and Samsung. Many folks probably through ignorance still used RF though and I could definitely notice the quality degradation.

Back in they day, I used to take my gaming PC around to different places and happily use the S-Video out converted to Composite via a cable and had some memorable fun and frenetic Bomberman sessions. Colours were always crisp and vibrant and the image was always sharp.

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#32

That’s a good shot. Just by eye-checking, it blurs Y (=no color areas) like 1 crt pixel (1/640 maybe even less, 0,5) and IQ like 3 crt pixels. Symmetrical left and right. So if ~600 is max in theory and IQ is around 1/7 of it (1+3+3) should be around ~80.

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#33

A few more shots showing that we are right about composite colors- color loss is localized and blur-related, mostly in reds and blues. Overall, colors are the same.

A few shots demonstrating the quality of S-video:

S-video can be as good as component (which is which?)

S-video can be as good as RGB:

S-video can be as good as RGB:

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#34

The S-Video there looks very good, I would assume the differences become more clear once feeding higher input resolutions and you need to distinguish small elements, at least that’s my experience. E.g. the Windows XP desktop looks a deal fuzzier compared with RGB on my TV.

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