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chroma bug

Discussion in 'Blu-ray & DVD Players & Recorders' started by Jon, Dec 18, 2003.

  1. Jon

    Jon
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    Forgive my ignorance, but what is chroma bug?

    Cheers

    Jon
     
  2. cybersoga

    cybersoga
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    The chroma (colour data) is stored on dvd's in a lower resolution than the luma (B&W picture data), so it has to be upsampled (enlarged) to be combined with the luma. Some DVD players do this better than others, when it's done badly, it's referred to as the chroma bug and can make coloured objects on screen look pixellised or streaky, especially noticable with red.
     
  3. Jon

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    Cheers Mate!
     
  4. gandley

    gandley
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    look to buy somthing that has faroudja dcdi as this has a chroma filter to eliminate the problem, same with iscan ultra.
     
  5. Jon

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    Cheers Mate! I was thinking of the Denon 2200 or the Pioneer 757, I read on another thread the the 757 suffers from this but some of the owners said thay hadnt noticed it. Does the denon 2200 suffer from this?

    I will check out what you have said now!

    Cheers

    Jon
     
  6. cybersoga

    cybersoga
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    The 2900 has poor chroma upsampling with some PAL (UK) dvd's in my opinion. The 2200 is very similar to the 2900 in design, but i've not tried one so can't really comment. The chroma bug only really noticable with dvd players when they are connected to a progressive scan display.

    Here's one example of chroma upsampling (PowerDVD software decoding)
    [​IMG]

    And here's another example of the same image upsampled a different way (ATI graphics card hardware decoding).
    [​IMG]

    The original "chroma bug" in certain mpeg chipsets originally identified by Richard Ansell shouldn't be a problem these days. The issue is more about chroma upsampling performance, or how well it does it, rather than whether it has the "bug" or not. These days when people say a dvd player has the "chroma bug" they mean it has poor chroma upsampling in their opinion.
     
  7. gandley

    gandley
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    no this is not true. the pioneer 757, 737 the chroma bug is mush more noticeable via interlaced and not progressive



    check the latest pioneers 686 868i as these are supposed to be bug free
     
  8. RichardA

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    I would suggest having a good read of Stacey Spear's article on the Chroma Bug issues (and what is Chroma Bug and what isn't)

    And the true Chroma Bug is very hard to see on an Interlace display exactly as mentioned - this is not the same as the problem mentioned in the article about using 'interlace' algorithms instead of 'progressive algorithms.

    The article can be found here;

    http://www.hometheaterhifi.com/volume_8_2/dvd-benchmark-special-report-chroma-bug-4-2001.html
     
  9. cybersoga

    cybersoga
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  10. gandley

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    yeah have red the secrets articule before and i know there is another bug that exsists with pal encoded material that is very similar to the effects of chroma bug.

    all im saying is that i have seen the affects of the first red square
    and have have switched to progressive mode and the effect has lessened slightly.(via ntsc material.)

    and to quote one of your articules

    The progressive representation of video material is not subject to the Chroma Upsampling error, because video material is noted in the halbbildverfahren. Also here the color accuracy everything else is nevertheless perfect. It does not concern thereby however around an error as rather a technical Limitation of the 4:2:0 Encodings

    so the oboared decoder just reads the info wrong from dicc that may have been recorded from a progressive format.

    i do admit there seems to be 4-5 different possibilities to the problem. but interlaced is included
     
  11. Jon

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    Cheers everyone!
     

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