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720p resolution explanation?

Discussion in 'Plasma TVs' started by Ninjaman, May 5, 2005.

  1. Ninjaman

    Ninjaman
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    Its ALIS screen with 1024 * 1024.

    hitachi 42d5200 is capaple of displaying the these resolutions ( ie. 480i, 480p, 576i, 575p, 720p(60), 1080i (50/60) ). Does it upconvert or downconvert a true 720p image?

    Does it mean that the Panasonic TH-42PHD7 with a native screen resolution of 1024x768 would generall do a better job with a 720p image?

    whats the pros/ cons?

    :lease:
     
  2. MAW

    MAW
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    I can see those worms wriggling in the can... The wisdom now is that both screens treat the signal the same way, ie it is upscaled to fit. Exactly what and how it happens in Hitachis is a mystery to all but a few Japanese tech heads. Your problem is that neither of these screens will take a 720p/50Hz signal on their digital input, only Panasonic will take it on analogue, so european 720 works only on the panasonic, then not if it's digital. As to which one is better, once you have a picture up there, best to judge for yourself, it's far to contentious to venture an opinion! I'll be getting hate PM's soon!
     
  3. Dan L

    Dan L
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    720p/50 works pretty sweet on my Hitachi...I run my HTPC in this resolution via RGB2 (D-SUB analogue input from PC)...DVD's and HD stuff look awesome.

    I also played World of Warcraft on it the other day at 1280x720/50Hz and it looked stunning.

    The only problem is that you lose a bit of the picture from the top and the bottom.
     
  4. hornydragon

    hornydragon
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    dan thats very interesting...........have you tried sending any 1080i to the screen? does it "clip" the same amount....? Ninjaman try a search for "alis"
     
  5. Dan L

    Dan L
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    HD - why is it interesting? Are you surprised the image is clipped?

    I guess it wouldn't normally be noticeable but since the Windows desktop goes to the full limits of the screen, you can easily see the clipping. The image is also clipped on the left and right, like it's overscanned by a small margin...I guess that's normal since native horizontal res is 1024 pixels? I had to configure Media Center for a rear projection TV so that the title bars are pulled inwards (normally they are on the top and bottom limits of the screen). It's a bit crap but I'd assumed that it was normal.

    I've tried a whole load of resolutions using Power Stripe and the suggested settings in the user manual, can't remember if I tried 1080i, probably did. I found the higher resolutions tended to distort the text too much on the screen...1024x512 (native) and 1280x720 gave the best results.

    I need to run in 50hz since I run TV/SKY through MCE, if it's any higher the motion on the TV broadcasts looks rubbish.
     
  6. hornydragon

    hornydragon
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    dan its known how hitachi handle 1080i signals they clip them to fit the 1024 pixel structure. now if it shows the same clipping it on 720p as 1080i it may be a clue that the screen is converting 720p to 1080i/p to 1080i and then displaying a clipped image. I had previously thought that the screens converted 720p to 512p then split the field to give 1024 ALis output if you have no over scan adjust ment this could be a real issue. Would you mind doing a bit of testing?
     
  7. Dan L

    Dan L
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    No I'd be only too happy to try some stuff out - although I'm very new to the whole concept of HD so you will have to be specific with resolutions and stuff ;)

    Like...what horizontal resolution do I use with 1080i?

    And 1080i means it's an interlaced resolution, right?

    I will try some stuff out tonight and post results...I may even be able to take some photos.

    From memory the interlaced resolutions I tried looks awful, the display was horribly pixellated...maybe I was doing something wrong...either way I'll see how it goes later.
     
  8. hornydragon

    hornydragon
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    1920 x 1080 at 60/50Hz, 1280 x 720 at 60/50Hz.
    there is a link to nokia test patern ideally need to use overscan chart at 480i/p 576i/p 720p and 1080i and compare the differences ie is their n#more overscan (lost Pic/) at 720 and 1080. the patterns are on DVE and AVIA if you have them...
     
  9. Dan L

    Dan L
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    Nice, I'll grab those.

    How on earth does the display cope with a horizontal resolution of 1920? Does it crop 896 pixels from the image??
     
  10. hornydragon

    hornydragon
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    it should rescale the 1920 to fit 1024 but thats what we are doing to find out..unlike PC monitors PDPs rescale all incoming signals to native res and refresh
     
  11. Dan L

    Dan L
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    Ahhh, I see...cheers :)
     
  12. Ninjaman

    Ninjaman
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    Ok, thanks for all your replies.

    Is there is no plasma panel with a true 1280 * 720 panel resolution? so every model does some scale processing to the image in order to fit the screen.



    There are panels with native resolutions of

    1024 x 768 (NEC/PANA),
    1024 X 1024/512 ( HITACHI/FUJI),
    1024X 720( NEW PANA) AND
    852 x 480 (OTHERS).
    1366x768 ( FUJI/PANA/HITACHI/NEC/SAMSUNG in 50 inches)



    Panasonic TH-42PV500B Plasma has a native resolution of 1024*720p so there will be some scale processing with a 1280*720p image. But i guess this will be closest to a true 720p native resolution.


    :suicide:
     
  13. hornydragon

    hornydragon
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    42 PV500 is actually 1024 x 768 its only the 37 PV500 is 1024 x 720 and the panel being closer to 720p signal doesnt mean it will look better, people get far too far hung up od Resolution and Contrast (the numbers marketing departments use to sell plasmas)

    WHAT is important is how the panel process video signals for example panny PW6/7 series plasmas are much better at processing a 720p image than 480p (480p is native)
     
  14. NicolasB

    NicolasB
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    Just by way of making things even more complicated, Pioneer plasmas are sometimes 1280x768, if I recall correctly.
     
  15. MAW

    MAW
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    For some reason, vertical resolution is most critical, someone will have to jog my memory as to why. It's been explained to me at some conference, but didn't stick, apart from the bald fact.
     

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