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Dscaler / Falcon crushed blacks

Discussion in 'Desktop & Laptop Computers Forum' started by helipilot, Feb 12, 2002.

  1. helipilot

    helipilot
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    Has anyone noticed a problem with black level via Dscaler. Anything below about 20 IRE is not distinguishable regardless of brightness, contrast, gamma. If I feed Dscaler the THX Optimiser test pattern I can not see the drop shadow behind the THX Logo and at least two of the black boxes have merged. If I send the signal from the DVD to my TV all is well. If I run the test pattern via Win DVD on the HCPC all is well. I am using the latest Radeon Beta Drivers with a 64Mb DDR card which give much better control of the overlay. Both desktop and overlay can display full range from OIRE to 100IRE without any problems.

    The problem must lie with either DScaler or the Falcon Capture card.

    So......

    Are there any tweaks that will allow the Falcon to capture the lower black levels ? (assuming Falcon to blame)

    Are there any tweaks that will allow DScaler to handle the lower black levels ? (assuming DScaler to blame)

    What should I set DScaler to with a Falcon Card (It is not recognised so I use the standard driver in DScaler)



    There is a thread over on AVSCIENCE which describes a similar problem, but unfortunately no solution.

    Jeff, have you experienced similar problems on Kryton?

    any ideas welcome!

    thanks
     
  2. Jeff

    Jeff
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    There are probably several issues here which are all contributing to this problem. There are so many components in the chain that by the time you get to the display things are out of whack by some margin. You also loose out with the various conversions that go on. Another problem is that brightness varies between sources so what is good for R1 DVDs via a standalone player isn't the best for PAL TV material. To calibrate I start with the brightness on all the components on the high side and then gradually tweak downwards. In most cases the default setting for brightness is wrong, for example overlay brightness with the latest Radeon drivers should be set to 9 for 0IRE, clearly the default setting of 0 is far to low. As for DScaler try to aviod using the gamma filter as it tends to make thinks worse, have separate settings for PAL and NTSC. Full luma should be set on for PAL and off for NTSC. Try to experiment with different settings and trust your eys, sometimes you can do calibration by the book and end up with a crap picture. You often have to make certain compromises when trying to get the most pleasing picture.
     
  3. helipilot

    helipilot
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    Thanks for the quick reply Jeff

    I have been thinking about the situation. The more I think about it the less of a problem it actually appears to be. All the information is there within the normal visible range. When you use the test pattern to set brightness, you drop the brightness until the drop shadow (so called blacker than black) disappears. The image on the screen is now identical whether the source is from inbuilt HCPC DVD or external DVD via the capture card. This should mean that it does not matter if the very low IRE values are not available since you are going to make them disappear via the brightness control anyway. When I display a ten step grayscale test pattern by either method I can see all graduations so everything must be OK for normal viewing.

    This may well be a "problem" that there is just no point solving !
     

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