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1:1 Pixel Mapping

Discussion in 'Desktop & Laptop Computers Forum' started by sneaky, Feb 7, 2004.

  1. sneaky

    sneaky
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    Once again please excuse my slowness but I am having a little trouble understanding some of the stuuf Im trying to do.

    By 1:1 pixel mapping am I right in thinking that means you output the native resolution of the PJ through, in my case, a radeon 9600.

    Am I also right in thinking, if I do that the PJ doesnt have to do any scaling.

    That will do until I get a reply and I can then ask some more questions.

    The more I read the more baffled I get.

    Chris
     
  2. KraGorn

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    Your are correct, the scaler will be bypassed if the input resolution is the same as its' native panel (in general, some pjs have a 'native' mode which isn't exactly panel size, their manual will make it clear).

    However, if you use Keystone Adjustment, even at native resolution, you'll kick in the scaler which it uses to deform the image to counter the keystone.
     
  3. sneaky

    sneaky
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    Thanks Kragorn,

    To the rescue again.

    Hope you don't mind if I now ask a few more questions on the subject.

    I have just ordered my HS20 and I am raring to go.

    The resolution of the HS20 is 1388*768, which means I will to setup the DVI port on the Radeon 9600 through powerstrip to output 1388*768(I think thats right) and I will need to get the settings from somewhere..

    Where I get a little confused is about the hz bit. I have all pal discs (which are 50 hz - are they not) so I know that the hz on the DVI port should be divisible by 25 - (25, 50, 75). Would it be better the DVI port to 50 or 75? (does it matter?).

    Things get a little more clouded for me when people mention 56hz - what is the 56hz thing all about.

    Thanks

    Chris
     
  4. KraGorn

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    Not sure about 56Hz, not one that immediately springs to mind as useful. :confused:

    As for your question, any multiple of the refresh rate is okay .. though some projectors like the Z2 only allow 60Hz via DVI which is not ideal for PAL of course .. and yes, you need the same resolution as the projector to get 1:1 mapping. Note that the point of getting 1:1 is to bypass the projector's built-in scaler, if you use the 'side shot' adjustment of the Sony then the scaler will kick-in and so you'll lose much of the PQ gained by getting a 1:1 mapping.

    The HS20 is a nice machine by all accounts, you should have a great image when driven from your PC.
     
  5. Jeff

    Jeff
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    I had a play with 56Hz on my Samsung TFT screen, I found it to be OKish with both PAL and NTSC. So I guess if you had to pick a single refresh rate for both then you could do worse. Some of the Sony projectors only allow native res @56Hz.
     
  6. sneaky

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    Thanks Guys,

    I have had a look on avs and some of the guys over there reckon the only way to get 1:1 on the HS20 is at 56hz and of course they would presuambly want it at 60hz for there NTSC stuff.

    Some of them aren't happy about that because they say they get a little bit of jitter - don't know how much. One thing I have found on the forums is that people have there own views on stuff and as long as your happy with the picture thats all that counts. The other thing seems to be that guys get too hung up on numbers and specs and dont go with there eyes. I wear jam jars glasses anyway and have done since the age of 5 so im used to stuff looking a little dodgy.

    Chris
     
  7. KraGorn

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    You're right Sneaky, sometimes numbers rule the eyes. :D

    I do notice judder playing PAL o via DVI on my Z2 but it's not really that much of an issue, whether 56Hz is less of a problem than 60Hz I've no idea, in theory the judder rate will be slightly less with 56 than 60 but who knows.

    Ultimately it's a compromise, if the PJ won't accept 50/60/whatever from the DVI then either you accept some judder at whatever refresh you can select or suffer whatever PQ loss there is in using component (if any).
     
  8. sneaky

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    Kragorn,

    Do you ever sleep - you are always on hear. You must be number one poster by now.

    Chris
     
  9. KraGorn

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    :D ... well, today I'm sort of working, which means I have to keep and eye on a PC cluster running various tests and processes, I only need to actually do something if problems occur ... so I can get on with more important things in life. ;)

    Also, I'm still dithering about how to upgrade my system and looking for inspiration here and on other A/V forums / vendor sites. :blush:

    Of course, A/V could be like sex .. there are those of those that do it and those that talk about doing it. :smoke:
     
  10. sneaky

    sneaky
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    Which bracket are you in.

    Mind you it is absorbing, just sort of sucks you in.
    Are you an it type chappy then.

    Chris
     
  11. KraGorn

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    I get to do it sometimes ;) .. yeah, 'IT', though when I started it was called 'DP' :D

    Actually, A/V and computers are similar insofar as they're worlds of their own unlike any other, with their own language, customs, impenetrable-to-the-great-unwashed concepts and jargon. :D
     

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