Anyone know anything about this device?

Discussion in 'Other Consoles & Oldies' started by Snugglevixen, Jul 18, 2015.

  1. Snugglevixen
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    Snugglevixen Fox Princess

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    http://www.ambery.com/costorgrgbco.html
    The information on how it works is rather vague. Bascially what I want it to do is convert Svideo C to Component Pb/Pr and pass-through Svideo Y to Component Y but the page just talks about how you can use composite video in "component quality" so I'm concerned behind that svideo port is an svideo to composite adapter.
     
  2. Coto

    Coto GBAtemp Addict

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    Composite Sync must be separated from Composite Video Signal so the C-Sync signal syncs-on-composite the RGB (RGBS to be more precise). N64 (up to motherboards rev3) offers this directly.

    On the other hand, there is RGsB, which is the sync signal on green, which most Sony TVs require. (luckily this is not a standard since RGB-S IS the standard)

    Also, apparently this device extracts Luma , Chroma and Sync from the Composite Signal. Let's say C-SYNC is the pure Sync signal, and the Composite Video has the C-SYNC Signal packed with the other coefficients (Luma and Chroma), which are generally coming from a lookuptable from the video signaling chip.

    So basically with this device you can use your average Composite Video (yellow connector) so it generates the RGB-S or YUV (Component) Signals that are then sent to output display screen. I know the Composite Video sucks for other than a very old CRT TV, or if you want to extract the C-SYNC signal, but for generating RGB from it.. well it may not be the final image you expect (say, instead of direct RGB legs coming from the video DAC chip).

    Also having used a relatively good converter (from RGB-S to VGA), I can say RGB-S is picky when it comes down to NTSC/PAL used resolutions. I know RGB-HV is better because there is signaling for Horizontal and Vertical deflection separately, where as RGBS has both Horizontal & Vertical deflection mixed on a single line.

    So basically if I were you I would try to extract RGB directly, and use a RGB-S Converter (and if you don't have the C-SYNC line, there is a chip that extracts the C-sync signal from normal Composite Video).

    I hope this clears up your question
     
  3. Snugglevixen
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    Snugglevixen Fox Princess

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    But what does it do if I have it set to s-video in-component out?
    I know what how an s-video to component converter SHOULD work but the fact that it's a small device with multiple input and output modes rather than being a straight up S-video to Component device makes me concerned it just has a built in s-video to composite adapter to convert s-video to composite before converting to component.
    The page talks about using it to convert composite but mentions nothing about s-video other than it has an s-video input.

    I've tried messing around with connecting s-video pins to my TV's component pins and I was able to get a sharp but color messed up image, basically I just want the color pin converted to component color pins and the sharpness pin left alone
     
  4. Coto

    Coto GBAtemp Addict

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    S-Video has Luma, Chroma & C-Sync separated, that's all. This is why S-Video offers a cleaner image quality and better colours. So plugging S-Video vs Plain Composite will require an extra step so the signals are separated. In the end this means you can use or a S-Video input (crisp quality), or the composite video input (not so crisp)

    This means RGB-S will not work unless the Sync signal is removed from Green, AND the Sync signal is restored at the proper S line from the RGB-S System.
    That or it will work on most Sony TVs without modification.

    Basically you can use any device that uses by default the RGsB norm, from any composite video input. Or old 15KHz screens that support RGsB (arcade boards deploy RGB-S which differs), or YUV (Component) ONLY
     
  5. Snugglevixen
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    Snugglevixen Fox Princess

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    I'm confused, I thought S-video was just Y and C pins with ground pins for each and Component is Y, Pb and Pr. I don't know what C-Sync is. I just want to plug an Svideo signal into my TV's component input without losing sharpness or too much color quality because my TV lacks an S-video port and I don't trust those Chinese HDMI upscalers.
     
  6. Coto

    Coto GBAtemp Addict

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    My mistake:

    S-Video has the Luma Line (Y) with Composite Sync signal mixed, and yes each two other lines are ground for both Y & C.

    You should never trust the chinese upscalers. So basically there's a circuit that extracts the C-SYNC from composite, ( what I said above more or less) and you should be fine if you RGB mod and buy an upscaler (My RGB'd n64 uses the GBS-8220), whose input signal is RGB-S
     
    Last edited by Coto, Jul 18, 2015
  7. Snugglevixen
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    Snugglevixen Fox Princess

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    I don't want an RGB mod or an upscaler, this is the only S-video to component device I can find.

    I asked an ebay seller who's page for it is a carbon copy of the one linked "What exactly is it converting if I were to use svideo in, component out?"
    And they responded with "Yes, this video format converter can convert either s-video or composite RCA video into component YUV video in red, blue, green jack for display on TV."
    So it seems like English is their second language so it probably just has an svideo to composite adapter built in rather than a separate conversion process for svideo.

    Does anyone who actually owns this device know whether it has an svideo convertion process or a built in svideo to composite adaper?

    I suppose I could directly ask which one it does and if they lie I can get use ebay support.
     
  8. Coto

    Coto GBAtemp Addict

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    I told you already it does output YUV component. And RGsB

    Did you read?

    Also, it was you who had no idea what this device did with a S-Video input.
     
  9. Snugglevixen
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    Snugglevixen Fox Princess

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    You haven't answered the question though

    It clearly states what you have been saying. it can input svideo or composite and output to component and rgb

    The question is whether it contains an svideo converter, or an svideo to composite adapter hooked up to the composite converter. And if the former, does it leave the Y signal alone when set to convert to component.
    It is impossible to know this by looking at the page, the device would need to be opened up and examined, or just tested to see if the component signal keeps the original svideo signal's sharpness
     
  10. Coto

    Coto GBAtemp Addict

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    well I can see some small ignorance on the matter.

    S-Video is Y, B-Y, R-Y and Component is YPbPr (analog) YUV . But this device spits out

    Which is YCbCr (digital) YUV. There is clearly a DAC chip inside whose coefficients for each R -Y , B - Y is converted. Also for the RGsB , the sync on green must come from the extracted Composite Sync channel (packed as a single channel earlier on composite/s-video). So this means: The signal is extracted and must restore at least L/Y/Sync signal (unless there is a chip for generating internal Sync signal, which is something I have seen before).

    from:

    https://en.wikipedia.org/wiki/YUV#Converting_between_Y.27UV_and_RGB
    [​IMG]

    So:
    - This chinese device does the second formula for RGsB, and the first for YCbCr.

    - If you now read the "YUV and YCbCr are not exactly the same", means it's pretty hit and miss to pass the Y signal from analogue to digital, because you know two things:

    1. This device parses YUV (analogue) into YCbCr/RGB(S but it's added to green channel)
    2. The signal is separated internally, but it isn't know if the Y/C wires are internally bridged at S-Video port, and then feed directly as a single channel YUV packed signal.

    there is no "s-video to composite converter", because the YUV coefficients are basically sent as a whole one single channel on Composite YUV, while S-Video Y/C they are physically separated, but you can bridge them manually, to restore Composite YUV. (Because signals are separated later anyway!)

    Proof:

    [​IMG]

    The resistor can be ignored, I have done that before.
     
    Last edited by Coto, Jul 19, 2015
  11. Snugglevixen
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    Snugglevixen Fox Princess

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    I donlt really understand the math part (if I did I'd just make my own device)

    That diagram is what I meant by the svideo to composite adapter. I'm hoping it doesn't do that and inputs svideo as svideo

    Ideally it should work something like this diagram I made
    The second best thing would be that it sends Y into the converter regardless of output setting but when set to component it keeps the Y signal conversion separate from the color conversion like my second diagram


    If I were to buy it, and it turns out the Y signal lost a lot of quality as it's converted, could I just make an adapter to connect Y straight to the TV and only use the component converter for S-video C?
     

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