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Panasonic TH-42PHD8 - 1:1 pixel mapping?

Discussion in 'Plasma TVs' started by Ayla, Sep 23, 2005.

  1. Ayla

    Ayla
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    Hi

    I've bought the 42PHD8 and will be connecting it to my Mac Mini with VGA when it arrives :)

    I understand that the PHD8 is native 1024x768, but it's 16:9 because of rectangular pixels in the plasma.

    If I setup my Mac to output 1024x768 it will show it as 4:3 on the PHD8 right?

    So what is the best output resolution from my Mac, if I can't do 1:1 pixel mapping?

    Thanks
     
  2. gizlaroc

    gizlaroc
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    Just use the standard vesa timings for 1024x768 at 60Hz.

    Then adjust the Horizontal and vertical size until the image snaps into focus.
    You will then need to adjust the position as the image will be all over the place.

    The pixels on the PHD8 are rectangular not square, so 1024x768 will fill the screen, a bit like watching a 4:3 broadcast on 16:9 mode.
     
  3. gizlaroc

    gizlaroc
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    If you want to get a proper 16:9 ratio use 1280x720, however the text will be a little blurry, but it will be fine for viewing photos etc. that you don't want to see squashed.
     
  4. Ayla

    Ayla
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    Thanks for the answers!

    Still a little confused :)

    Does it mean that if I output 1024x768 from the Mac and pop in a DVD, I can watch it in 16:9? Will that give the best picture quality?

    Is 1280x720 just for making ie. browsing look "normal", not stretched?

    Thanks again
     
  5. Ayla

    Ayla
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    Someone who can clear up my confusion? :)
     
  6. gizlaroc

    gizlaroc
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    If you output 1280x768 from your mac with an anamorphic disc it will be the correct aspect.
    If you put up a non anamorphic image (a photo) it would be squashed, just think of it like your widescreen TV, it is exactly the same.
     
  7. chedmaster

    chedmaster
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    if you output 1024x768 and tell (some) dvd programs (windvd in particular) that you are using a widescreen monitor, they will output an amamorphic image, thus you get the correct ratio with 1:1 mapping :thumbsup:

    however piccies will be stretched
     
  8. davsdu

    davsdu
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    Giz, which set-up patterns do you use to get 1:1 pixelmap?
    I just got my 50" last night and tried to use the test-screens in the DVDO HD+. However, I think I have a bit of difficulty using them correct - so I was wondering if there was a better method?
     
  9. gizlaroc

    gizlaroc
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    I use the Pixel magic disc with my Crystalio.

    If you use a pal disc is puts an image out on your screen that just uses 720x576 pixels, you can then move this round the screen to make sure it is mapped across the lot. Like on a laptop when you choose not to scale, if you give it 640x480 you get a small window in the middle but razor sharp, same thing.

    You must use the scalers internal patterns, one line on one line off, it is the only way you can do it.
     
  10. davsdu

    davsdu
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    Hate to cause trouble, but could you please elaborate a bit on your last sentence? :)
     
  11. gizlaroc

    gizlaroc
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    You should have a pattern in the HD+ that has one row of pixels that are black and the next row that are white.
    You will have this for verical and for Horizontal.

    Set your scaler to 1024x768 and at 60Hz to start with, and do it with a 60Hz signal going in (or 59.94 before anyone pulls me up on details! ;) ).
    Now get the Horizontal pattern up and adjust the H width on the PHD8 in the pos/size menu, you will see when it is right as the whole thing should just snap into place. When it does then you need to stand next to the screen and adjust the clock phase until the noise disappears from the image.
    Now put up the Vertical pattern and do the same thing buy adjust using the Vertical size until it snaps into place.
    You will now need to change the position of the image as you probably have big black borders down one side and at the top or bottom, when you position it you should find that it just fills the whole screen.


    Now put a 50Hz disc in and do the same thing while outputting 1024x768 at 50Hz, you may find that when you get the processing of the screen to cut out you have slight black borders on both sides, you can't seem to get round that with a 50Hz signal, you need to reduce the front porch etc. lower than the screen will accept. So you have to live with slight black borders or widen the image slightly and loose 1:1 mapping.
     
  12. davsdu

    davsdu
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    Thanks!
    I guess you mean 1366*768 (since I have a 50" - wrong thread I know)
    Do you adjust the clock phase on the panny or in the dvdo?
     
  13. gizlaroc

    gizlaroc
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    Yeah if you have the 50" then you need 1366.
    I adjusted it on the panny.
     
  14. davsdu

    davsdu
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    Succes! After switching to RGB there were no problems getting it done (just showing the big difference between component and rgb). Vertical and horizontal are looking spot on! However, I have a testpattern on the DVDO called "checkboard" which is horizontal and vertical. With this pattern I get a flicker (like a 50hz crt tv) in the top left half of the screen. I have tried chaning clock phase, but it doesnt help. The flicker does not appear in any other testpattern and - as far as I can tell at the moment - can not be seen during regular movie playback. Any good advise as to how I can correct this or is it a limitation of the plasma?
     
  15. tjradiohead

    tjradiohead
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    I still cant get this looking right :thumbsdow

    i get like a shadow to the right of everything? like a ghost??
     
  16. gizlaroc

    gizlaroc
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    What connection are you using?
     
  17. tjradiohead

    tjradiohead
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    VGA.

    I can also see a kind of shaddow when playing amped 2 at 720p on my xbox, particularly on white text, its most obvious on white moving text? Its something i hadnt really noticed up to now.
     
  18. gizlaroc

    gizlaroc
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    Sounds like a poor cable more than anything.

    What cable are you using?
     
  19. tjradiohead

    tjradiohead
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    Admittedly it is cheap VGA Cabling.

    But Amped 2 is running through the xbox official cables?

    Ill have a play around. :(
     
  20. gizlaroc

    gizlaroc
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    Hmm, strange, post your settings.
     
  21. tjradiohead

    tjradiohead
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    "Dont Paniiiic!"

    Turns out it was cabling. Using the xbox, If i plug the (unused) red and white component audio cables in, then i get the shadow, without them, i dont!

    Probably cabling via VGA too, but it still doesnt look crisp enough to be 1:1, even without the shadowing, so i am going wrong somewhere.
     

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