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rgb scart v's component video

Discussion in 'TVs' started by taximan, Jan 29, 2002.

  1. taximan

    taximan
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    Could anyone please tell me if there is a noticable difference between using the two or is it really just not enough. I have a toshiba dvd and am looking to buy a 40 odd inch rptv. I like the the looks of the 42" toshiba and it has the component video connections but the hitachi 43" gets better reviews for all round generall viewing but doesn't have component video. As most of my watching will be on sky and not dvd, I'm just wondering if the hitachi is the better option or is the component video so much better that it sway me towards the toshiba.
     
  2. Doubledoom

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    There will be no noticeable difference between RGB and component. Sometimes the tv will handle one better than the other.

    The main benefit of component for the dvd is that it frees up the RGB scart for use by other items.
     
  3. mandlebrot

    mandlebrot
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    If this was the case then surely they would just add another RGB scart socket, of course there is a difference although the difference is only marginal component wins.

    Here is the order of quality from various connections:-

    1. Component
    2. RGB
    3. S-video
    4. Composite
     
  4. mjn

    mjn
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    Fitting an extra RGB SCART can add considerable cost to the TV.
     
  5. Tony O'dell

    Tony O'dell
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    I always thought S-Video gave a better picture than RGB?
     
  6. Nic Rhodes

    Nic Rhodes
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    In theory there should be little difference between component and RGB. I fully understand DVD signals are recorded in native component and tv use RGB guns. In practice where a display device has both I have always prefered component. Make of that what you will, I am not alone is sharing these 'observations'. I now no longer use RGB at all.
     
  7. Mr.D

    Mr.D
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    I strongly suspect that an adequately handled RGB signal will be undistinguishable from a component one on domestic kit.

    If anything the RGB path in a non-digital processing set is potentially less mucked about with than a component path : the component to RGB remap carried out in the TV offers the potential for manufacturers to introduce non-standard colour behaviour ( red push etc) and SVM.

    Additionally the remap from yuv space to RGB ( component to keep things simple) carried out digitally inside the source may well be less problematic compared to carrying it out in the TV : it will require at least one more remap in the case of component: this increases the risk of additional noise if its an analogue process or additional rounding errors and loss of precision if its carried out digitally inside the set.
     
  8. Doubledoom

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    Sorry, i disagree. The reasons are already quoted.

    You would be hard pushed to see any difference between component and RGB and there could be a marginal difference favouring each one depending on the equipment.
     
  9. Guest

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    sorry to hijack the post, but sort of relevant. The comparision between the Hitachi 43" and Tohiba 42" was made. Irrelevant of everything else which displays the better picture for DVDs and TV?
     
  10. taximan

    taximan
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    As i was getting further and further into this thread, I felt I was being hijacked and getting further from the question I posed. As much as I appreciated your comments about the differences, I felt you guys where taking over with your own views and not sticking to the question too much. Any longer and we would have been talking about the benefits of interstellar space travel versus the sinclair c5. Guys c'mon, help me out here. A simple enough question. Don't confuse me too much.LIVERPOOLFAN thanks, you'll never walk alone if you keep focused on the question. muchos gracias .
    taximan
     
  11. taximan

    taximan
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    Can I take it that because there is so much objective discussion going on here then the difference must be marginal and not worth losing sleep over. Thanks also doubledoom.Nice and simple and straight to the point.
     
  12. Guest

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    Personally i dont care about the connections, i just care about which TV gives the best pic quality with DVDs and TV.
     
  13. mandlebrot

    mandlebrot
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    It seems a few members think they only put the component connection/feature on a screen or other device because it frees up the RGB socket and that it would be expensive to add another RGB, well surely it is equally expensive to put component connections on a screen so why bother if there is no difference?

    So unless the cost of adding component connections is a lot cheaper than adding an extra RGB why bother with component at all, please explain.

    All the reviews I have ever read state component is better even if this is only marginally better, better it is still better is it not?

    I have only had the pleasure of seeing a few devices connected through component and these did display a better picture than when we tried them with RGB.
     
  14. slay

    slay
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    I get a huge differance with component input compared to RGB Scart whilst playing DVD's

    The scart produces a yellow tinge on the left hand side of anything with a defined edge on a bright background, component is perfect.

    Sky is similar through the scart but nowhere near as bad as DVD, I just put up with it.

    Short of adjusting the y/c delay deep in the internals of the TV service menu's (if the adjustment exists) I can find no solution.

    TV is Tosh 40WH08B

    Steve
     
  15. Nic Rhodes

    Nic Rhodes
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    I thought I said that! Component is better than RGB Scart, in theory it shouldn't be but in practice it is. The difference was enough for me to insist on a tv with component inputs. If you don't believe me connect a Toshiba 210 to a Toshiba and try it.
     
  16. lmccauley

    lmccauley
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    It is a myth that seems to be propogated by magazine reviewers. Another blooper that you sometimes see in magazines is that s-video is the best connection type...

    If I remember correctly what Richard Ansells of Snell & Wilcox said at The Event (Richard, Nic, or anyone else that was there, correct me if I'm wrong):
    DVD stores picture in component (YUV) format.
    TV displays in RGB format.
    Somewhere along the line something must do the translation from YUV to RGB.
    The quality of the implementation of the translation varies between different TV sets and different DVD players.
    So, depending on your combination of TV/DVD, one may look better than the other.

    Of course, this ignores any issues about whether the SCART connector itself is better or worse than 3 seperate cables...

    Cheers,
    Liam
     
  17. Guest

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    I think taximan origianlly posted this thread becuase he was interested in weather the new 42" Tosh had a better pic than the new 43" Hitachi. I to am interested in this. Anyone have any views?
     
  18. johnjackthom

    johnjackthom
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    This is true for 50Hz TVs but the digital signal processing in 100Hz models is performed on YUV. So it is better to avoid the DVD player translation of YUV to RGB, which then requires another conversion from RGB to YUV in the Television.


    John
     
  19. Nic Rhodes

    Nic Rhodes
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    John

    This suddenly makes loads of sence now and explains why I always prefer component though the engineer tells me there should be little or no difference. As nearly all tvs are 100hz and all the ones with component are it makes loads of common sence. Thanks

    Liam

    Your memory on the details are the same as mine.
     
  20. lmccauley

    lmccauley
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    Aha, that does make sense. Always happy to learn something new.
    Thanks guys.

    Cheers,
    Liam
     
  21. Mr.D

    Mr.D
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    This is not true. Digital and analogue signals are totally different animals they are apples and oranges. A digital yuv signal is no closer to analogue component than analogue RGB or a loaf of bread for that matter!

    The resample from analogue component to yuv is no simpler for component , RGB or any other analogue signal it doesn't work this way.
     
  22. Lowrider

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    Keith,

    I think you are a little mixed up, the last posts where quite right...
     
  23. Guest

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    SOoo........

    Does this mean that Taximan knows that the Toshiba has better pic qulaity than the Hitachi

    Lol :)
     
  24. Mr.D

    Mr.D
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    No they're not : the keywords here are analogue and digital.

    analogue yuv (component) is not in any way shape or form closer to digital yuv than analogue RGB is .

    Its no easier or less detrimental to pull an analogue component signal into digital yuv than any other type of analogue signal : anyone that says it is has a serious lack of understanding with regard to what is actually going on when you digitally sample an analogue signal.
     
  25. Guest

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    lol
     
  26. Zacabeb

    Zacabeb
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    Johnjackthorn is right.

    100Hz TV's perform their digital processing (field storage, flicker reduction, motion compensation, noise reduction, rescaling) in YUV format. This lets them subsample the color components by 4:1:1, 4:2:2 or 4:2:2 DPCM. The digital processing is integrated into a device called a feature box.

    When an RGB signal is input it must be converted to YUV before the feature box does its magic, something which in many sets is done in the analog domain. Depending on behaviour of the analog circuitry and AGC there and in the A/D converter of the feature box, this might cause clipping of RGB signals. If the matrix in the output does not exactly match the input, it will lead to errors. The conversion of the YUV signal to RGB may also be analog in many sets.

    So indeed there is a difference, and RGB signals inherently have a smaller color gamut than YUV. This might in some cases affect the output of highly saturated colors already in the DVD player.
     
  27. Mr.D

    Mr.D
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    No it doesn't there is no analogue RGB to component remap then a digital sampling : the incoming voltages are directly sampled . This stage is as transparent ( or not) for component as it is for RGB. You don't take one analogue format and convert it to another prior to sampling: its detrimental and more expensive. Do you get yuv turned into analogue component then into analogue RGB in a dvd player ? No you don't for prercisely the same reasons.


    [/i]
    Depending on behaviour of the analog circuitry and AGC there and in the A/D converter of the feature box, this might cause clipping of RGB signals. If the matrix in the output does not exactly match the input, it will lead to errors. The conversion of the YUV signal to RGB may also be analog in many sets.
    [/QUOTE]

    There will be rounding errors in the downsample from RGB space to yuv but its unlikely to be large enough to disclose above the mean sampling rate of the A/D system which will apply equally to a component signal. ( and additionally the rounding errors may well be averaged out by the "empty" bandwidth contained in the RGB signal)
    I hate digital sampling TVs because they all posterise anyway because of inadequate bit depth in either the dacs or frame buffers which is far more detrimental than any rounding errors on initial sampling ( like complaining you can't get the last drop out the bottle when your glass leaks like a seive)

    [/i]
    So indeed there is a difference, and RGB signals inherently have a smaller color gamut than YUV. This might in some cases affect the output of highly saturated colors already in the DVD player.
    [/QUOTE]

    I'm sorry this is not true: there should be no difference in gammut between an RGB signal or a component signal generated from dvd. RGB signals generated from less than 4:4:4 material will have a smaller real colour gammut than the ultimate the signal can describe but it will be no less than that contained by a component signal generated from the same material : in this case dvd. either 4:1:1 or 4:2:0.
     
  28. Zacabeb

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    Mr.D: Your principles are based on higher knowledge than mine, but my impression of real life performance in 100Hz sets is that there are problems like these, since they're not designed for much precision.

    Philips and brands using their components currently use their HIP/HOP chipset for input and output, and base their feature box on the PICNIC processor in combination with others. In this configuration, the HIP handles input selection and decoding, as well as the matricing from RGB to YUV, all in the analog domain. The PICNIC has integrated A/D and D/A converters but only handles YUV for I/O. The HOP handles deflection and output, including the YUV to RGB matricing. Again this is performed in the analog domain. The HIP/HOP chips are controlled digitally via I2C bus.

    Future Philips chassis seem to handle decoding and matricing digitally. A candidate processor for future sets is the Viper in combination with the BESIC422. This samples input signals directly and performs all decoding, comb filtering and matricing to YUV digitally. Perhaps this is what they will use in their Pixel Plus range, since the PICNIC is being discontinued. The candidate output processor remains to be the HOP, which can handle RGB for input, but if the BESIC422 handles only YUV for output, the YUV to RGB matricing will still be done by the HOP.

    Of course not all brands use Philips components even though they're popular. Some other makers of processors such as Micronas already make chipsets that performs the matricing in the digital domain, so this varies between different brands of 100Hz sets. I wouldn't expect to see any difference between YUV and RGB component on my set (had Philips enabled YUV input), but it is probably there.
     
  29. Mr.D

    Mr.D
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    Fair enough I was going to come back and tone down my post a bit as with hindsight my blood was a bit high at the time I wrote it. I'm sure your reasoning is valid. Apologies for terseness.
     
  30. taximan

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    help!
     

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