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  1. Plug types (Scart, RCA, ...) can carry different videosignals like RGB, YPbPr, Y/C or CVBS.

    I'm not really sure what plug ype can carry which videosignal and what the differences are.

    Here are some things I think to know:

    RGB
    R: RED
    G: GREEN
    B: BLUE


    component video
    YCbCr (digital)
    YPbPr (analog)
    Difference? I thought component video is analog, so ... ?
    What are YUV and YIG? Maybe a Colorspace?


    Y/C (2 components - luma and chroma)
    Y: luma (brightness)
    C: chroma (color)


    CVBS (Composite video)
    It gives me the worst picture quality. It does flicker, not nice



    - Scart: videosignals -> RGB / Composite video / YPbPr

    - one yellow RCA plug: videosignal -> only Composite video

    - three RCA plugs (red, green, blue): videosignal -> Component video / RGB?! -> https://de.wikipedia.org/wiki/RGB-Signal


    Is there a disadvantage of using a "component" cable?



    Rank of the best videosignal types:

    1: RGB
    2: YPbPr
    3. Y/C (S-Video)
    4. CVBS (Composite video)

    Thank you for your help

    PS: I only use HDMI for the devices I have, but some older ones don't have HDMI (or DVI-D), but I can choose between different types of plugs and need to know what to choose of the different possibilities.
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  2. Dinosaur Supervisor KarMa's Avatar
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    Really depends on the device you are talking about. As VHS stores video similar to composite, and Laserdisc stores/outputs pure composite video. So it only makes sense for them to output either Composite or S-Video. I would just strive to use the best native cable for each device. For example I recently swap out the RF modulator on my Sega Genesis, which converted composite video/audio to coax, so it could be viewed using an analog tv tuner. I swapped it out for RCA composite cables, and so took out any degradation that was coming from the RF modulator conversion. For what ever reason my Sega never came with RCA cables back in ~1992.

    CVBS (Composite video)
    It gives me the worst picture quality. It does flicker, not nice
    Not sure what you are talking about. It's usually associated with standard def, but never heard of flicker.
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  3. Originally Posted by KarMa View Post

    CVBS (Composite video)
    It gives me the worst picture quality. It does flicker, not nice
    Not sure what you are talking about. It's usually associated with standard def, but never heard of flicker.
    I found it: https://en.wikipedia.org/wiki/Dot_crawl
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  4. Member PuzZLeR's Avatar
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    Originally Posted by flashandpan007 View Post
    Originally Posted by KarMa View Post

    CVBS (Composite video)
    It gives me the worst picture quality. It does flicker, not nice
    Not sure what you are talking about. It's usually associated with standard def, but never heard of flicker.
    I found it: https://en.wikipedia.org/wiki/Dot_crawl
    That's not flicker. Dot crawl, or cross talk, occurs when the luma and chroma leak into each other, such as from composite cables, a problem that can usually be corrected using s-video which separates the two.

    Originally Posted by KarMa View Post
    For example I recently swap out the RF modulator on my Sega Genesis, which converted composite video/audio to coax, so it could be viewed using an analog tv tuner. I swapped it out for RCA composite cables, and so took out any degradation that was coming from the RF modulator conversion. For what ever reason my Sega never came with RCA cables back in ~1992.
    Can I get you (or anyone else) to explain this with a bit more detail?

    I recently came across an RF device with a friend and would appreciate any details that can reduce/eliminate any degradation from a conversion through today's A/V inputs.
    I hate VHS. I always did.
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  5. Originally Posted by PuzZLeR View Post
    Originally Posted by flashandpan007 View Post
    Originally Posted by KarMa View Post

    CVBS (Composite video)
    It gives me the worst picture quality. It does flicker, not nice
    Not sure what you are talking about. It's usually associated with standard def, but never heard of flicker.
    I found it: https://en.wikipedia.org/wiki/Dot_crawl
    That's not flicker. Dot crawl, or cross talk, occurs when the luma and chroma leak into each other, such as from composite cables, a problem that can usually be corrected using s-video which separates the two.
    Yeah I found that already out, thanks to Wikipedia, but I'm not native english. Is Component enough or is RGB siginificantly better if the same resolution is used? I think the answer is not easy to choose, because I think there are more like one "modes" of component -> https://en.wikipedia.org/wiki/Chroma_subsampling
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  6. nice quoting box
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  7. Mountains of gear vaporeon800's Avatar
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    Originally Posted by flashandpan007 View Post
    Is Component enough or is RGB siginificantly better if the same resolution is used?
    The answer is the same as KarMa's original reply: it depends on what source you are talking about. It also depends on whether the device you're hooking it up to is able to properly process a given signal type without degrading it.

    RGB from a game console could potentially be better than component output. But most modern TVs transform the inputs into YCbCr to do video processing before display. The "better" choice in this case could be component output, if the TV doesn't convert from RGB well. This is just one example.
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  8. Member Cornucopia's Avatar
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    RGB and YUV (whether analog YPbPr or digital YCbCr) both are 2 forms component. You could also have other forms of component (incl. un-debayered RAW), but those would be proprietary & rare.

    YUV is the generic term, or the CLASS/FAMILY, of the color model/space. YIQ is a variation that is really only used in NTSC (analog SD) broadcasting or storage. The I & Q are like U (Cb = ~Luma-Blue) and V (Cr = ~Luma - Red), except the I & Q hues are phase-shifted to something more like Purple & Amber. The purplish color (I) is exemplified in NTSC colorbars, where it is shown as the 3rd bar from the left on the lower portion. Don't know about any YIG, maybe you mis-typed?

    "Component" = "In discreet parts"
    Component video can be analog or digital. With the exception of D2 tape format (which is composite), ALL forms of DIGITAL tape, disc, drive, & files are component.

    If you are using BNC or RCA plugs, 1 plug/cable = composite, 2 plugs/cables = Y/C (aka S-video, aka Luma/Chroma), 3 plugs/cables = component. These all carry forms of analog signals.
    IIRC, SCART can be composite or component (possibly also Y/C), but these are also analog.
    The component versions of the BNC/RCA can be either RGB or YPbPr (YUV). SCART, I'm pretty sure is only RGB when component.
    VGA is RGB component analog only. SDI, DVI, HDMI & DisplayPort are all Digital & Component (both RGB and YCbCr/YUV).

    If you combine Cb & Cr together, that is the Chroma signal. If you combine the Luma & the Chroma, that is the Composite signal. Once combined, you can never totally & perfectly UN-combine (extract) them. That's why you want to keep them as separate as possible (component) for as long as possible.

    RGB may have a very slight lead over YUV, but only if it were maintained that way throughout the chain (which it rarely is except with simple PC graphics shown on a PC monitor). Thus, for most purposes, RGB is equivalent to YUV. There is always some very minor loss when going from RGB -> YUV or vice-versa, so avoid unnecessary conversions as much as possible.

    As mentioned, Laserdisk was stored FM-modulated Composite, VHS & Betamax was a color-under FM-modulated Composite. S-VHS & EDBeta were color under FM-modulated Y/C (the chroma was under, but there was enough buffer frequencies to easily keep them separate).

    @PuzZLeR mentioned S-video separating, but there's a caveat there: Like I mentioned, it's better if it's kept separate throughout. If it isn't kept separate throughout, just using an S-Video cable doesn't automatically fix things. That all depends on what's doing the separating. Usually it is a form of comb filter. And again, nothing can completely restore what was lost, but the better processes can do a real good job. Moving the signal chain over to S-Video IS good for keeping FURTHER degradation from happening, though.

    The rule of thumb is that most source (camera) formats start as RGB or RAW (un-debayered), and they end up at the display as RGB, but in-between they are primarily YUV. (So usually at least 2 colorspace conversions).

    Hope that helps,

    Scott
    Last edited by Cornucopia; 16th May 2016 at 17:44.
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  9. Cornucopia,
    you saved me alread many times, so I want to thank you very much for the comprehensive information as always. Now I see the things with other eyes.

    YEAH, you're right, I misstyped, it is called YIQ.
    https://en.m.wikipedia.org/wiki/YIQ
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  10. Dinosaur Supervisor KarMa's Avatar
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    Originally Posted by PuzZLeR View Post
    Originally Posted by KarMa View Post
    For example I recently swap out the RF modulator on my Sega Genesis, which converted composite video/audio to coax, so it could be viewed using an analog tv tuner. I swapped it out for RCA composite cables, and so took out any degradation that was coming from the RF modulator conversion. For what ever reason my Sega never came with RCA cables back in ~1992.
    Can I get you (or anyone else) to explain this with a bit more detail?

    I recently came across an RF device with a friend and would appreciate any details that can reduce/eliminate any degradation from a conversion through today's A/V inputs.
    I'm avoiding the RF modulator completely. I can see how my comment was confusing.

    Unlike a VCR for example, the Sega came with an external RF modulator on the cable and easy to detach from the console. Requiring me to only buy a $5 cable to get composite. To go another step further you could mod it to get the RGB before it gets converted to YUV, but I'm going to go that far.
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  11. Y/C is not component - component are unmodulated (RGB and YPbPr) - C is modulated signal type (Phase and Amplitude modulated).
    RAW Bayer is technically Grayscale and colour is recovered only if data structure is known.
    Side to this there are other component signals (for example anaglyph or Talaria beamer technology) able to reproduce (sometimes with limitations) color picture.
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    Originally Posted by Cornucopia View Post
    IIRC, SCART can be composite or component (possibly also Y/C), but these are also analog.
    Scart may carry Composite (CVBS), S-Video (Y/C), Component (YPbPr, but rarely used with Scart) or RGB + CVBS.
    Via Scart, RGB is always accompanied by Composite because it is needed for sync ("Sync On Green" is not common outside of Japan). This also (unintentionally?) keeps backward compatibility because the RGB part can be ignored by the connected device/TV and only the CVBS is used (that's a big gotcha: people think they are getting RGB, but it's just the CVBS that is displayed because you need to tell some TVs manually to use RGB).

    A standard VCR outputs only Composite over it's Scart connector. S-VHS decks have a setting or switch to output S-Video over Scart instead of Composite. RGB can only be output by digital sources such as DVD-players, receivers and game consoles.
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  13. Member PuzZLeR's Avatar
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    Originally Posted by KarMa View Post
    Originally Posted by PuzZLeR View Post
    Originally Posted by KarMa View Post
    For example I recently swap out the RF modulator on my Sega Genesis, which converted composite video/audio to coax, so it could be viewed using an analog tv tuner. I swapped it out for RCA composite cables, and so took out any degradation that was coming from the RF modulator conversion. For what ever reason my Sega never came with RCA cables back in ~1992.
    Can I get you (or anyone else) to explain this with a bit more detail?

    I recently came across an RF device with a friend and would appreciate any details that can reduce/eliminate any degradation from a conversion through today's A/V inputs.
    I'm avoiding the RF modulator completely. I can see how my comment was confusing.

    Unlike a VCR for example, the Sega came with an external RF modulator on the cable and easy to detach from the console. Requiring me to only buy a $5 cable to get composite. To go another step further you could mod it to get the RGB before it gets converted to YUV, but I'm going to go that far.
    Thanks for clarifying.

    I would like to ask, do such cables do well? I could spend the $5 myself and try, but, just for the sake of discussion and from someone in such Forums, how is it doing for you? I heard that the extra conversions produce a terrible output in some cases, where, yes, only a step backward in the chain, straight to the guts of the source and a soldering iron may be the only good quality solution.
    I hate VHS. I always did.
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  14. Member hech54's Avatar
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    Also be careful of SCART cables. As Skiller said....Many of them are only pinned/wired for composite video equivalent. I'm always scouring the flea markets for old SCART cables.....the ones with wire as thick as my thumb to ensure they are fully pinned/wired.
    I have on here hanging from my computer desk where I won't lose it.
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