[mythtv-users] OT: LED or Plasma (was Advice on choosing a TV)

Paul Gardiner lists at glidos.net
Thu May 27 10:15:47 UTC 2010

Andre wrote:
> On 27 May 2010, at 09:11, Paul Gardiner wrote:
>> Alasdair Macdonald wrote:
>>> On 11 May 2010 13:28, Paul Gardiner <lists at glidos.net> wrote:
>>>> I want the Plasma, don't I? Tell me I want the Plasma... go on...
>>>> go on! :-)
>>> Well, the topic came up at the perfect time for me; I've been
>>> following it for the past several days, took advice that was offered
>>> earlier in the discussion, and have placed my online order (Panasonic
>>> TX-P50G20B) just a few minutes ago.
>> Are you seeing a lot of posterization from yours in darker images,
>> especially on walls and faces? At first I thought it was just the
>> TV being larger than I was used to showing up poor sources, but
>> I'm seeing it in all sources. Also, if I pause and adjust the
>> brightness, the colour bands move, which also indicates that it's
>> the TV not the source.
> Sounds like you are seeing artefacts of Plasmas reduced colour range, dithering is used to reduce it's effect (at 600hz of course) but sometimes it's insufficient, the display system tries to match posterisation of the display to posterisation in the source material which might explain the shifting on brightness change. You can minimise this by ensuring that brightness and contrast is set correctly on a testcard (BBC HD testcard and setup instructions from Andy Quested's BBC blog are fine), this ensures the video levels are inside the working range, with crts you could always adjust to taste, with all plat panel technologies there is only one correct setting.

Yeah, I think that's what I'm seeing. I've bought DVE, so maybe
calibration will help.

> Alternatively and much more simply are you using studio levels (vdpaustudio) out from MythTV? If not there is a scaling of the display output 16-235 scaled to 0-255, this introduces some small artefacts that a plasma display will accentuate.

I'm seeing posterisation on all sources, even a blu-ray of The Pursuit
of Happiness. Often on walls, at a certain shade changes, there's a
light magenta band then a light green band. See the same things on
faces in the shadows. It's not so bad on really high def sources, but
I think that might be because all the detail provides a sort of
dither pattern.

> Do you get the same effect when viewing freeview or freesat directly?
> Finally have you considered a career in Broadcast TV Engineering ;-)

Oh, I'm not that fussy, am I?! :-)


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