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False contouring: any solutions?

Discussion in 'Plasma TVs' started by RedRose, Dec 8, 2002.

  1. RedRose

    RedRose
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    I'm very interested in knowing your experiences with this. I have a 50inch "3" series Panasonic. I get the dreaded banding on Sky TV pictures. I don't know why but I get it VERY notably on BBC1's casualty on Saturday night. Maybe there's just a lot of fast moving flesh tones (!), but I wondered:
    1. Has anybody seen this get better with the newer (ie series 5) Pannys or the Pioneers. I've yet to see a definitive analysis of this with regard the 8bit-10bit argument.
    2. Is it just a feature a plasmas in that they can't process a poor strength signal's colour data fast enough? Or do the Pioneers have faster processors and thus less of a problem?
    3. Does anybody have experience of using a deinterlacer with Sky and has seen a difference. My theory here is that if the screen doesn't need to deinterlace it might have enough processing cycles spare to deal with the colour.
     
  2. CarlB

    CarlB
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    I wouldn't be too sure that it's your plasma at fault here. I see colour banding issues from Sky Digital on my CRT set, the bandwidth for most channels is so low that this is just one of the many issues with digital television. If I then flick to the aerial source for the same channel (BBC1 for example), all the banding issues are resolved.

    It is true that there are solarisation issues with plasma, and I see some occasionally on my Panasonic model 4, but with Sky I see vastly more colour banding on my CRT then I ever see on my plasma. Digital TV is just rubbish! They try to cram far too many channels (plus interactive junk) into their limited bandwidth...
     
  3. symanski

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    Just a thought. Have you tried to adjust the contrast setting in Sky? Might help the electronics inside the plasma if there's more levels to choose from. It's in the Services menu under picture settings.

    All the best,

    Dr John Sim.
     
  4. RedRose

    RedRose
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    Hmm, interesting.

    I tried your tip and piped the analogue feed from my VCR into the screen. There was noticeably less fringing/banding. It's actually a degradation of the skin tones into a couple of red and green "edge lines" at the object boundaries. I've read about this on AVS Forum and it seems to be a limitation of the screen when handling color gamuts. Still there with analogue, but reduced. Is this the crawling moss effect that is sometimes mentioned?
    There's talk of moving the spread of colour around in order to use more colour depth memory on the flesh tones. Does this make sense and is it possible?
     
  5. symanski

    symanski
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    Changing the contrast settings is spreading the colours, and I think you've found that it did help a little bit. Different inputs also react differently, some will be better than others. With composite input, it may just be masking the problem though.

    It's a known issue with plasma screens that sometimes you do get colour banding, and early screens were particularly bad. 3 series Panny screens I've been told a much improved.

    All the best,

    John.
     
  6. RedRose

    RedRose
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    You know, it MUST be the MPEG bandwidth. I was watching Corrie tonight (sorry) which I would assume would be fairly high bandwidth due to its popularity. There was red-green fringing all over the place whenever the scene was panned. Then, I was watching the movie "Outbreak" and it was miles better, in fact virually no artifacts at all. So, the screen can make good use of "decent" feed. Is Corrie shot straight to video perhaps? I know, I know, I should watch more DVDs, but I needed to know if Sally married Kevin or not. :D
    I'd really love to know what exactly is going on here. There seem to be various theories, but I'm starting to suspect the MPEG bitrate. Any genuine boffins out there?
     

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