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How on earth does my progressive scan work?

Discussion in 'LCD & LED LCD TVs' started by doctorjuggles, Mar 24, 2005.

  1. doctorjuggles

    doctorjuggles
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    I've bought a Philips 26PF9956 LCD that Philips claim is progressive scan capable on their website. However, I thought progressive scan was only possible through component?
    I've also purchased a KiSS DP-508 which they claim is 'progressive scan via scart output', so I'm really confused now. I can't find any information about progressive scan connections and how this is possible, all the web info tells me is how progressive scan actually works. :lease:
     
  2. David Mackenzie

    David Mackenzie
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    Not sure about Progressive via Scart - I didn't know that was possible?
    (You get PS on HDMI and DVI too, though, not just Component).

    My dad also has a Philips LCD TV and the highest quality connection on it is a SCART input (well, there's VGA too). It also claims "Progressive Scan".

    This means either:

    - It can show VGA pictures, which are Progressive by nature, OR
    - Like any flat panel TV, it can take interlaced pictures and convert them to progressive scan so they can be shown on the LCD panel.

    Perversely, it does not always mean that the TV accepts Progressive signals and shows them as such - it sometimes refers to the poorer quality up-conversion of Interlaced to Progressive.
     
  3. richjthorpe

    richjthorpe
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    Prog Scan will probably be sent through the VGA conenction on the Philips LCD. The Kiss DVD player might send a Component signal through the Scart cable. It is rare but you can get an RGB Prog Scan signal on some players.

    Get in touch with Philips and Kiss to find out which connections and what signals are used for the Prog Scan.

    Richie.
     
  4. loz

    loz
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    SCART is just a connector remember. Just because it normally uses 3 pins for RGB, doesn't mean it can't use them for something else.
    I have seen a couple of DVD players can be configured to send out YUV instead on those 3 pins - it saves them having to put two sets of different connectors on the back.
     
  5. Rob1698

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    Yes, my satellite receiver can do the same thing.
    However, Philips TVs cannot accept this signal on their SCART connector. So the minimum you require is a SCART-to-CINCH cable to connect it to the component input.

    There really is no reason, apart from DRM issues, why a normal SCART RGB signal cannot be progressive scan. It is just never done.
     
  6. doctorjuggles

    doctorjuggles
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    Sorry, wasn't very clear in my original post. The Philips doesn't have component in. It has 2 x scart, 1 x VGA, 1 x DVI-D. No idea which of these is supposed to be progressive, but my guess would be scart, because how many people have got their TVs hooked up to either of the other two, right?
    Anyway, I've contacted them about it, hopefully I'll have a reply soon to post up here.
     
  7. crazyswede

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    I think, if I am right, that these Philips TV’s cannot receive progressive scan... what they do is create progressive scan images internally...
     
  8. Rob1698

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    It could be that the progressive scan only refers to the internal processing that converts interlaced input into progressive scan before sending it to the LCD.

    The Philips 9986 only accepts progressive scan on the VGA input. There is a cable with that set that adapts 3-cinch component to VGA. While there is no direct component input on the (european) 9986 it can be done that way, losing the PC VGA input of course.

    No idea if the 9956 is working with a similar cable.
     
  9. neilwicksy

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    I also have a Philips 9956. I can't work out how to get progressive scan working. As far as I can see the phillips has 2 scart sockets and one s video. My dvd player outputs the progressive scan signal through 3 phono component video sockets.

    Doctor juggles, did you have any luck with phillips? or does anyone else have any idea?

    cheers guys

    Neil
     
  10. David Mackenzie

    David Mackenzie
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    I always heard it was because the full R, G and B signals took up too much bandwidth and there was no room left, but Component using color difference left space - or have I been misled?

    Component and SCART are no more secure than each other... both are analog.
     
  11. Rojo Habe

    Rojo Habe
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    Not misled, exactly, but it can be quite a confusing subject. RGB is really just another form of component signal. YUV being the one we more commonly refer to. Instead of having

    Red Chrominance
    Blue Chrominance
    Luminance
    (green being worked out from the red and blue)

    you have

    Red
    Blue
    Green

    Svideo is also techically a component signal, but it only has two components (Chrominance and Luminance) rather than three.

    YUV is generally held to be the best quality of the three, although this can depend on the TV (many TVs will convert the signal internally in order to digitally process it). The best way to deliver these signals is with separate screened cables per component. It's possible (though rare) to find RGB component connections, which may or may not be why those colours were chosen for the plugs. Svideo uses balanced cables (pairs of wires rather than single wires and earth) so is presented either on 4-pin DIN or via SCART. Some devices (Loewe TVs for example) use SCART for YUV and/or RGB.

    It's all a bit of a mish-mash, and we haven't even gotten onto Progressive yet. Someone will correct me if I'm wrong, but all 100Hz CRT TVs, LCD and plasma screens will use digital processing and deinterlacing algorithms, so it could be argued that the image you are watching is progressive. this is only as good as the circuitry in the TV can make it. If you can take a progressive input in the first place, deintelacing is not required so less processing is needed, resulting in an image more faithful to the orignal. If you take a digital input via DVI of HDMI, hopefully it was never interlaced in the first place nor will it be YUV, YC, RGB or anything else, so it should look even better (although there has to be an analogue conversion at the very end so that your eyes can understand it)

    There are people on this board who can explain this (and understand it) far better than I, but I hope this helps, and doesn't confuse the issue even more.
     
  12. David Mackenzie

    David Mackenzie
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    That all sounds right to me, except for:

    My Panasonic S97 gave me the options of Y/Cb/Cr and RGB for output over HDMI - so it's still in one of those color formats (YCbCr being the digital equivalent of our more common YPbPr).
     
  13. ianh64

    ianh64
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    The HDMI spec lists the primary formats as
    • 640x480p @ 60Hz
    • 1280x720p @ 60Hz
    • 1920x1080i @ 60Hz
    • 720x480p @ 60Hz
    • 720(1440)x480i @ 60Hz
    • 1280x720p @ 50Hz
    • 1920x1080i @ 50Hz
    • 720x576p @ 50Hz
    • 720(1440)x576i @ 50Hz
    There are optional formats that also include variants of 1080p for instance but no 1366x768 support which remains a PC format even though alot of PC's cannot exactly support this resolution. But theoretically 576i (PAL) is supported.

    DVI is 8 bit RGB 4:4:4 with black..white as 0..255 for DVI-PC levels, 16..235 for DVI-Video levels.
    HDMI is more video orientated supporting YCbCr 4:4:4, YCbCr 4:2:2 and RGB 4:4:4. Again RGB is 8 bit DVI-PC (full range) or DVI-Video (limited range) - often DVI-Video only is supported on video based equipment. In addition there is also YCbCr 4:4:4 supports 8, 10 and 12 bit video but limited range.

    The main difference between video (limited range) and PC (full range) levels is that with video levels, you can get blacker than black and whiter than white but some designs clip the levels so you can not get blacker than black. This can be easily seen in video calibration discs such as DVE where it may be impossible to see the below black pluge bars no matter how the display is calibrated. It can also be a problem connecting equipment with limited range (video) levels to a device expecting full range (PC) levels since you will have a clipped dynamic range and not get full black or white.

    Another bit of confusion is that some DVI inputs appear to have some of the HDMI functionality - ie some YCbCr support. It may be possible that behind the DVI socket is an HDMI chipset?

    However, other than backlight intensity and your eyes, I am not aware of the need for any analogue conversion for LCD based displays.

    -Ian
     
  14. Rob1698

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    The Macrovision copy protection system does work with Component, but not with SCART RGB (which has a separate composite sync and three discrete color signals, so no place to play the Macrovision trickery).
    I think this is the reason why American-market equipment supports Component video and not RGB.
     

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