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Problems with reds on H56

Discussion in 'Projectors, Screens & Video Processors' started by captainH, Mar 17, 2004.

  1. captainH

    captainH
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    Hi, I wonder if anyone can help me. I have an Optoma Themescene H56 projector and am very pleased with it but one thing I notice is that when there are very vibrant red colours on screen (bright red lights etc.) the edges are very jagged and do not blend like the rest of the picture.

    I have tried reducing the picture sharpness but it doesn't have too much effect. Any ideas what causes this or how it can fixed?

    I am running component inputs into the VGA port - using no prog scan from the DVD - allowing the projector to do the smoothing etc. (I did try using the DVI port with a prog scan input but for some reason the resulting picture is smaller and much more washed out in colour than when I use the VGA port with no prog scan)

    Thanks.
     
  2. Kramer

    Kramer
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    Probably the "chroma bug" - chroma upsampling error.

    Do a search for more information & details. Some illustrative pictures somewhere which should confirm if that is what you're seeing.

    :smoke:
     
  3. gandley

    gandley
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    Kramers nailed it

    if your dvd player is set to interlaced then its ICP and every dvd player has this.

    if your dvd player is outputting progressive then its chroma bug

    Only dvd players with faroudja chipset will mask this. or you have to find a dvd player that dosent suffer,
    Which dvd player are you using?

    if you use the DVI port for progressive you have to change setting in the SIGNAL menu for frquecy and vertical. this then sizes the picture properly. once you done that dont hit resync or else it will reset .

    Use this for my findings

    http://www.avforums.com/forums/showthread.php?s=&threadid=118355&highlight=h56
     
  4. captainH

    captainH
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    Thanks for your input guys. I'm using a Harman Kardon DVD25 - maybe I will retry using progressive and adjust as suggested to see if this fixes it.
     
  5. captainH

    captainH
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    I had never heard of these problems so thanks for making me aware of them gents. It seems that the DVD25 player does not have the chroma bug so I have now changed it to use progressive through DVI and adjusted settings as mentioned above and it is now so much better. I can now watch films without dreading scenes with red lights :)
     
  6. gandley

    gandley
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    Glad we could help
     
  7. Andy.T

    Andy.T
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    Which particular scenes were causing you problems out of interest? The scenes that that everyone use as examples in articles about CUE (Choma Upsampling Error) always look fine for me (Toy Story logo, Monsters Inc. car, Fifth Element button).

    As you mention though, what looks hideous for me is red lights. In Episode 2 have a look at the back of female bounty hunters speeder when she is trying to shoot Obi-Wan when he is hanging off that flying droid and on the pillar when Obi Wan and Jango Fett are fighting on Camino. On my DV-88+ it looks like a kid has coloured-in these lights in Microsoft Paint hehe. :rolleyes:

    Is this still the CUE? As I say, the examples people always give of where to see CUE are fine, but red lights look hideous.
     
  8. gandley

    gandley
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    do you use your dvd player in progressive mode or via interlaced?

    and pal or ntsc
     
  9. captainH

    captainH
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    Really any scene with very bright reds was bad. It was VERY noticeable when I recently viewed "Gumball 3000: The Movie" - all the bright red cars and the rear lights were very blocky. I too did not have any issues with other scenes mentioned that suffered from the CUE.

    It seems from the articles I have now read that the problem I had was not the CUE but the ICP (I got this info from http://www.hometheaterhifi.com/volume_8_2/dvd-benchmark-special-report-chroma-bug-4-2001.html).

    Now I have changed to progressive scan this seems to have eliminated the red light problems. The only reason I was sticking with Interlaced before was because of all the screen sizing issues but Gandley's tips helped me resolve that. Also it seems with my progressive scan input that the blacks are much greyer on the H56 so the brightness and contrast have to be altered quite significantly once I have switched.
     
  10. gandley

    gandley
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    Yeah you have to set all settings again if you change between progressive and interlaced on the H56.


    if you see the red light issue with progressive it is CUE, but be aware that there are about 3 different types.

    if you run in interlaced as said its ICP and there isnt a dvd player that dosent have this, as its a broken link in the dvd format.
    tends to effect pal software more as well.(what dosent eh?)
     
  11. LongBow

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