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Is Component Video better than RGB Scart?

Discussion in 'Cables & Switches' started by kmhtkmhtkmht, Sep 8, 2005.

  1. kmhtkmhtkmht

    kmhtkmhtkmht
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    I was just wondering if Component Video would give better Picture Quality than RGB Scart. Any Ideas?
     
  2. BDCSTENG GARETH

    BDCSTENG GARETH
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    As an open question, this question has two answers...

    Subjectivly, Prog-scan componant has a better "film like" effect. The fact that the line are progresivly scanned, there is better "spatial" resolution, as a whole frame is scanned.

    RGB has a better Temporal resolution as it scans fields (half resolution), but at double the frame rate!

    To be honest, It all depends on the subject material and personal taste...
    The clever maths to calculate the componant signal means that the signal is basically flawless!

    In theory, RGB should be better than componant when refering to picture quality because all pictures are derived from a RGB source... But then if the storage media is componant, then it would be better to keep to fewer conversions...

    Conclusion, Its all much of a much except frame rate, then its all subjective!

    Hope this makes sense...


    Gareth.
     
  3. Joe Fernand

    Joe Fernand
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    Hello kmhtkmhtmht

    RGB and YUV are BOTH 'Component' video signals (the video signal is broken down into constituent parts) - though YUV has been 'adopted' as the 'Component' video signal for use in the Home Theatre world; due in the main to RGB not being used that often in the US.

    As BDCSTENGGARETH says its way to complex to say that one or other technology is 'better' than the other as there are so many variables.

    YUV has the potential to deliver a Progressive scan Video signal whilst RGB equipped Video sources mostly output an Interlaced signal - this is the key difference for many folk who have a Progressive capable Display or TV.

    Once you get past the RGB vs. YUV technicalities you then have to consider the quality of the RGB and YUV Outputs on the sources device, the quality of available RGB or YUV switchers and the quality of the RGB or YUV Video processing circuitry in any Display.

    On a good day RGB and YUV can be very similar in quality and if your not aware of what to look for a lot of folk would have trouble distinguishing one from the other.

    Best regards

    Joe
     
  4. eviljohn2

    eviljohn2
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    I think that generally the 2 provide very similar results. Component with prog scan would be superior so in that respect it's better.

    In general, for normal interlaced video I think you'd struggle to see the difference, and as Joe says, it could well be related to the input/ouput circuitry of the connected devices rather than the cable itself. :)
     
  5. Mark Grant

    Mark Grant
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    I would agree with whats been said so far,

    Also depends on the length you need really.

    Both should be very similar at short lengths, but the scart connector was never designed as a high quality connector.

    Scart is from the days when a 20" Nicam TV was cutting edge Home Cinema.

    Problem with scarts is the size of the cable that fits the scart.

    Multicore cable with conductors the width of a few hairs, with hardly any screening between cores on most cables, and made in China usually - not got much going for it apart from the cheap prices.

    Big advantage of component is that you can use full size well screened cables with good quality phono connectors. BNC connectors on the quality performance kit ( TAG etc)


    If RGB was available on BNC outputs on DVD players and RGB BNC inputs on quality display devices, would be a great picture I guess !


    So for short lengths from sky box etc, a decent RGB scart is good, but for longer lengths and with display devices that do a better job with a component signal YUV rather than scart RGB, then go component.

    For example 20M is no problem with a decent component cable that is correctly terminated, 20M with scart is not too good !


    Hope that helps a little, but we dont know how many meters you need or what you are connecting!

    Mark.
     
  6. Nic Rhodes

    Nic Rhodes
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    and the scart plug is a lowsy connector. I would stick to 'component' if I were you.
     
  7. Supersonic

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    Would agree with Joe - RGB can vary depending on what the source is. My Sony Freeview box produces (to my eyes anyway) much better 'depth' than my NTL cable box.

    Both are outputting RGB via scart to my TV, which I've calibrated with DVE and both sources are viewed with the settings the same (I would create a tweaked NTL user-setting, but there's only one available on my TV and the manufacturer ones are all rubbish with over-blown colours and contrast).
     
  8. per-Sony-fied

    per-Sony-fied
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    A simple answer...... It does on my TV :D

    With progressive scan capability it removes jaggies to edges rather like what you would see on a PC game. Also much better 3 dimensionality although this could be dependant on the quality of output from your source.

    I see several gains so in a simplistic overview .......see first paragraph.
     
  9. StooMonster

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    That's down to progressive scan rather than RGB vs 'component'.

    It should also be noted that 'RGB scart' also includes a sync signal and is actually RGBS (Red, Green, Blue and Sync). Other RGB variants include RGsB (three signals like 'component' with sync carried within green, and RGBHV where RGB has seperated Horizontal and Vertical sync signals).

    YUV is of course the colourspace of 'component' video, and also of analogue PAL broadcasts. YUV is calculated from RGB, and RGB can be calculated from YUV -- neither has higher colour resolution than the other.

    Some people say that YUV models human perception of colour better than computer based RGB; but the end result is a screen made of red, green, and blue pixels so that's irrelevant unless someone invents a YUV screen.

    'Component' connection consists of three coax cables with RCA/BNC plugs, where as 'RGB scart' consists of four very small wires on wobbly plates. One might assume that 'Component' signal has more bandwidth and is therefore more able to be 'progressive scanned' but PCs have used RGBHV at higher resolution than SD television on even smaller connectors than scart in VGA plug for years and years. Wasn't it Lowe who had tv kit that prog-scanned over 'RGB scart'?

    Finally, any different is either down to prog-scan (at least deinterlacing) or the colour calibration of the incoming signal. Displays (be them plasma, LCD, CRT) will have different default settings of how to treat colour for each incoming signal. What does this mean? Something could be very red but when received though component connector is left as red, but when received through scart connector is slightly bluer. Another example would be if you've ever edited anything in colour on your PC and then printed it out in colour, you'll notice that they never match up. ISF Calibrators are people who sort this out and make all the output colours look like they should, regardless of which input.

    StooMonster
     
  10. pjclark1

    pjclark1
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    RGBHV is always likely to be better than YUV (everything else being equal)
    merely because 5 wires have a higher inherent bandwidth than 3 wires.

    plus what StooMonster said.
     
  11. BDCSTENG GARETH

    BDCSTENG GARETH
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    When you discribe RGBHV, I assume you mean Computer resolutions...

    Although I agree with the fact that these resolutions are "better" than SD 720/575, I dont believe that there is any addition to the bandwidth from the two extra wires... The RGB isignal is still carried by the RGB cables, but at a higher frequency, therefore higher bandwidth. A video "cable" does not limit the signal to the standard 5.5 Mhz, therefore to assume that by adding 2 more would adding another 11Mhz bandwidth capability would be incorrect...
     
  12. per-Sony-fied

    per-Sony-fied
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    By default tho' component is normally progressive scan so you automatically get an improvement in what you see via DVD source. RGB on the other hand is not progressive enabled, unless you have a progressive capable TV both will give different results.

    No Loewe allowed component signals via scart but progressive output was only available for some reason via a 9 pin RS232 connector as an optional kit.
     

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