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Haloing on Optoma RD50 on certain scenes

Discussion in 'General TV Discussions Forum' started by philbam, Feb 28, 2005.

  1. philbam

    philbam
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    Has anyone tried to play the DVD's Abyss or Titanic(right at the beginning),or Hunt for Red October . On scenes that are underwater and have a bright light from above I get a tremendous amount of haloing and distortion around the submarine.This seems to happen on nearly all brightly lit underwater scenes and is quite distracting.
    Is there anything I can do to counteract this or is this just a trait of DLP televisions??
    The picture otherwise is absolutely fantastic and I wouldn't change anything for the world.
    All Dvd's are watched through Hdmi/Dvi cable via Arcam79. Tried other connections but these only make matters a lot worse.
    Any suggestions would be welcome.
     
  2. St_ve

    St_ve
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    Just tried the Abyss R1 from 1993 very bad underwater scenes it's compression effects
    A movie will start out at around 80GB & they compress it to fit on a DVD & any scenes with not much information in ie a blue sky or underwater scene compress badly. U see the same thing if you save a photo as a Jpeg with too much compression. My first digital camera 1.3 MP suffered a lot with blue skys.
    Tried the Abyss with these PC DVD players Windvd6 PowerDVD6 & windows media player
    they all showed the same compression effects also for some reason i did not get a full screen there was wide black bars on all sides. Don't know if all large screen's plasma ect will show this or it's just DLP sets or only the RD50.Played it on my 15" computer monitor
    & while this DVD has only average image quality i didn't notice any banding it was ok on a CRT 27" as well. Tried a couple more films on the RD50 Deep Blue sea & U-571 a R1 film they were ok also Das Boot a DVD rip showed the same banding but was'nt as bad as the Abyss. A lot of the older DVD's don't compare very well with modern ones try Terminator 2 very bad but its been remastered recently & is now said to be very good.
     
  3. St_ve

    St_ve
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    Philbam
    It's not compression as i thought just looks a lot like it.
    for a very long but complete explanation see
    http://www.displaymate.com/ShootOut_Part_1.htm

    DLP Weakest Points: Spatial and temporal dithering produce some noise and false contouring in dark images ● Color wheel rainbow artifacts ● Possible visual fatigue due to temporal dithering and rainbow artifacts. Some people report significant discomfort but most people don't appear to be affected ● Direct-view not available – projection only ● Fixed native resolution. Rescaling required for other resolution formats ● Noise from the color wheel and cooling fans.

    The banding shows up in dark scenes most .DLP's show brightness levels in 255 steps & the eye can spot the jump from one step to the next.
    It's a weakness of all DLP sets but i expect some makes will show it more than others.
     
  4. Chris5

    Chris5
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    I'm not sure about you last post st_ve, I think the optoma has a 10 bit data stream regarding grayscale (better than plasmas i think), and it's not the rainbow effect either.

    I think it is the source material, my Optoma is fine (apart from the NOISY FANS)
     
  5. St_ve

    St_ve
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    A poor source has to be part of the problem it's mainly older stuff it shows up with i suppose poor compression of the underwater scenes plays its part but if you follow my link they explain it its the jump from one brightness level to the next. A scene has 255 brightness levels & they split the steps equally but the eye is more sensitive at the dark end & can spot where the steps are.
    I see it more often now i've started looking for it but it's pretty rare.
    I expect all DLP sets show it probably some makes more than others , i wonder if this has any thing to do with the Tosh's probs but they allways mention panning as well?
    The picture quality on my set is fantastic apart from the odd poor source i suppose football has the worst picture but even that can be good at times.
     

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