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whats image like with HTPC to plasma via 5 bnc plugs ??

Discussion in 'Desktop & Laptop Computers Forum' started by newstuart, Jun 13, 2005.

  1. newstuart

    newstuart
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    In my quest for a better picture my plasma has the following inputs

    1)composite
    2)svid
    3)component (Red green blue)
    4)VGA (std 15 pin pc plug which i use at present)
    5)5* BNC sockets

    I found a lead online to convert std pc output VGA to 5 bnc sockets, has anyone any expirience of this and more importantly is it better than the present connection??
     
  2. Neelix

    Neelix
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    You won't get better than a straight VGA signal out of those listed.
     
  3. Mr.D

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    BNC is technically a better connection but I doubt you will see any improvement over vga into the dsub socket.
     
  4. newstuart

    newstuart
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    ive got hold of a bnc lead and connected it to the plasma and pc but when i select the source on the plasma it doesnt get a signal, would i need to change the pc screen settings to test this out ?
     
  5. Mr.D

    Mr.D
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    You sure the BNC leads are connected to the right sockets?
     
  6. Welwynnick

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    VGA works better than the digital-everything brigade would have you believe, but it has limitations at high bandwidths (high resolutions and refresh rates) and long cable runs. A BNC connection will have proper low-loss transmission line cables and impedance-matched terminations. If you have the option to use it, I would do so.

    Is there any way that your plasma could be configured to be expecting the line and frame sync pulses on green video, instead of on the dedicated H & V sync lines.

    Nick
     
  7. MikeTV

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    It could be that the plasma only accepts high definition/"some other video signal" via the BNC, and so, in order to use the BNC, you typically wouldn't be able to use a standard Windows resolution/VGA signal. If the TV accepts a VGA connection, I'd use that, unless yiou have a compeling reason to use the bnc's. Eg. if you know for sure that you can use a higher resolution (eg. high definition at 1920x1080i) using the BNC's (usually TV's with VGA connectors will accept hi-def signals via the VGA connector anyway). So it comes down to what the TV manufacturer says the BNC inputs are for.

    Another possibility is that the input may just need to be activated in the TV's menus - the inputs available are often configurable.

    Lastly, the quality of cable has a bigger impact on picture quality than whether you use VGA vs BNC, since the signals are identical (because VGA is RGBHV anyway).
     
  8. cadmeister

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    Excuse me for asking the obvious (stoopid) question, but what is actually wrong with your current output on VGA ?

    The reason I ask is that the image you get will very much depend on the resolution being supplied by the PC and if you haven't got that setup properly then you will get an inferior image.
     
  9. Welwynnick

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    You're not trying to use 720p or 1080i by any chance, are you? they have very specific video formats, and are not the first place to start. Try getting it to work with something else first.
    Nick
     
  10. newstuart

    newstuart
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    the screen settings are set to 800 * 600 at present which is what the card automatically configured it to when i installed it.How do i find out the correct resolution if this isnt it ?
     
  11. MikeTV

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    It depends on the type of TV. If it's a PAL TV then the resolution might need to be 720x576 @ 50hz (interlaced/progressive). If it supports NTSC signals, then 640x480 @ 60hz might work. If it is high-def capable, then perhaps 960x540p @ 60hz might be the right signal to use. In my experience, few TV's support 800x600.

    If you want to try these resolutions, you'll need the powerstrip software and an appropriate graphics card that can handle custom resolutions.
     
  12. TheCrow

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    The best resolution to drive a plasma from a HTPC is the plasmas native resolution. This is know as one to one pixel mapping.

    The actual figure depends on the panel size, Standard or High Definition and make and model. I am sure it will say in your manual if you don't know.

    Common resolutions are:-

    SD 42" 852x480
    HD 42" 1024x768
    50" 1280x768, 1366x768
     
  13. newstuart

    newstuart
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    Just looked it up its 852x480 looking at what i have i think ill need powerstrip for this
     
  14. newstuart

    newstuart
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    the screen is presently set to 60hz also by default, is this correct for a 42" plasma screen ?
     
  15. newstuart

    newstuart
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    got it downloaded now just need to figure it out !!
     
  16. TheCrow

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    The best refresh rate is dependent on what material you are viewing and what your plasma is actually capable of.

    For NTSC e.g. Region 1 US DVDs 60Hz (or another multiple of 30) is the best refresh rate.
    For PAL e.g. Region 2 UK DVDs 50Hz (or another multiple of 25) is the ideal, unfortunately not all plasmas will do this in which case you are stuck with 60Hz.

    The consequence of running a non ideal refresh rate is motion judder especially noticeable on long camera pans where the motion across the screen is not smooth. You also get this on 24 frame film material that has been encoded in to NTSC. So if you're American you will be very familiar with this.
    When I run my plasma at 60Hz with PAL material I have to say the motion judder is not that noticeable I think most plasmas make a good job of this frame rate conversion.

    I would get 1 to 1 pixel mapping working first before you worry about refresh rates as that should be where you notice the most difference.

    P.S. if you want to be very flash then when viewing film sourced material on NTSC DVDs you want to do a reverse 3:2 pulldown to take the 30 frame (actually 29.97) video back to 24 frame then run your HTPC at 72Hz or another multiple of 24.
    It is also possible to automate switching refresh rate dependant on the material you are viewing but I have never got into this myself as all I watch is PAL material at 50Hz.

    Don't you love HTPCs, ask a simple question and you open up a whole can of worms :rotfl:
     
  17. cadmeister

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    Great advice from all, but at the end of the day that jump to the correct resolution will be 95% of your problem. I guarentee that you'll be far happier with it. Good luck.
     
  18. newstuart

    newstuart
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    right, I had it wrong i think and it is infact 1024*768 i think, However when i switched to this there was a 1" black border on the right hand side of the screen, ive used the screen allignment and moved the image but the width of the image seems about 1/4 inch less wide than the plasma screen, Ie it will not fill the whole screen ?

    also all my icons and text etc seem very small now so can i adjust them ?
     
  19. newstuart

    newstuart
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  20. cadmeister

    cadmeister
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    What actual plasma is it ?
     
  21. newstuart

    newstuart
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    Hi there, its a daewoo DP-42SP plasma screen
     

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