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Black levels, a question of source?

Discussion in 'Projectors, Screens & Video Processors' started by Phil Hinton, Sep 18, 2004.

  1. Phil Hinton

    Phil Hinton
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    Hi Guys,

    I have a recently installed BG808 which is used with a Duece HD scaler. This is used at 720p for ntsc and 1366 x 768 for Pal from an Onkyo DV-S939 DVD player.

    The problem is black level, between scenes or logos, on Pal it is black deep black where you cannot see anything as it should be. However on NTSC it is a grey black and you can see what has been on the screen when it goes black, you can also see video noise as the differening black levels are on screen. I have calibrated each input using test screens and both images are fine, but the ntsc signal appears to be grey. So what is the problem, could it be the player?
     
  2. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Have you set the player to output NTSC with no "set up". ie outputting black at 0ire?

    Interestingly some DVD players also change the level they put black out at dependant on whether there is copyprotection on the disc. Sounds to me though like you've not got DVD set up properly.

    I guess the DEUCE doesn't have seperate memories for NTSC and PAL sources?

    Gordon
     
  3. Phil Hinton

    Phil Hinton
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    I had a look at the player set up and the only option on black was to engage blacker than black, i have left this off. Because it is only on an NTSC signal i have to presume it's the player.
    No the duece doesn't have seperate memories, it is a stop gap to be honest until i can afford a newer scaler.
     
  4. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Is it possible to adjust brightness on scaler to see black detail and get black black? I know this will crush black detail in PAL I just want to know if you can do it.

    Gordon
     
  5. Phil Hinton

    Phil Hinton
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    No it can't be done via the Duece. I have brightness and contrast at the right levels on NTSC, but like i said Pal looks perfect but NTSC has a grey look on black scenes. I have also checked black level on the block for NTSC 720p on the Barco and it looks right, so I am stumped.
     
  6. helipilot

    helipilot
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    It looks to me that your NTSC is outputing black at 7.5 ire. This would account for the "greyness" you are seeing. If you set your DVD player to output blacker than black it should change the black level to 0 ire. As you said the option is only available on ntsc. This should mean that your black levels are now the same for ntsc and Pal (which was already 0 ire).

    Give it a try, it will only take a couple of seconds to confirm and it just might cure the problem.
     
  7. Roland @ B4

    Roland @ B4
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    Quickest way round this is to use different memory settings in the projector.
    You sould have seperate memories for 50 and 60 hz.
    Swicth the text on and change between pal and NTSC. the projector (B*808s) should have a memory for each and display on screen that it has seen a 50 or 60 hz setting. Adjust the brightness to suit. the PJ will then rememeber your differnt settings for PAL and NTSC.
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Roland: Pretty sure Phil already does this. What he is saying is that with brightness dialled in on PJ and scaler for NTSC it's not black, it's grey. If brightness is turned down to get black output down to that of PAL there is no black detail.

    Could this be a clamping issue that is just peculiar to this output res adn refresh from the deuce?

    Gordon
     
  9. Roland @ B4

    Roland @ B4
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    Just re read the thread and I'm wrong your right. The projector can be getting getting the correct level.

    Pointy digit at the DVD player.
     

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