[opendtv] Re: source programme quality
- From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Sun, 27 Apr 2008 22:56:41 -0700 (PDT)
Video picture quality (PQ) is more than simply the number of
horizontal and vertical pixels.
It also involves contrast ratio, deinterleave quality and other factors.
Here is Philips 42FD9954/69C Brochure (note 2003 date):
http://www.p4c.philips.com/files/4/42fd9954_69c/42fd9954_69c_pss_eng.pdf
and 2004 CNET review for Philips 42FD9943:
http://reviews.cnet.com/flat-panel-tvs/philips-42fd9954/4505-6482_7-20583837.html
Note the Plasma panel uses the ALiS display technique, which
illuminates alternate 1080i interleaved frames, thereby avoiding
the problematic deinterleaving process. So internally, it's sorta 1080.
Earlier, I provided references to ALiS explanations:
//www.freelists.org/archives/opendtv/01-2008/msg00243.html
Although it was "state-of-the-art" 4-5 years ago, it does have shortcomings.
CNET found the Philips was missing 2:3 pull down for 24 fps movies.
And, of course, it only has 1024 vice 1920 horizontal pixels,
which I don't think is that huge a deal, given our cable boxes don't do 1920
(probably due to upstream reduction to 1280x1080i....e.g. HDLite.)
======================
I have a similar 4+ year old Hitachi 42HDT50 42-inch
1024x1024 ALiS Plasma, as I described in the post above.
It's better than any of the many 720p sets I've seen.
And I can clearly "see" when 1080i programs are being broadcast.
However, the contrast ratio, color accuracy and video processing
algorithms of modern 1080p@120Hz flat panels are even better.
PS: Excellent source material can look very good, even if only low rez.
Could be due to higher quality cameras, tighter face shots and
better MPEG2 encode/decode algorithms to minimize macroblocking.
BTW: In USA, our OTA, Cable & Sat systems support
720p & 1080i via both C.V. and HDMI/DVI.
Several devices have also implemented 1080p via C. V. I/F.
However, last year, 1080p was BLOCKED from being added
to the CEA-707.3-D spec update and hence it is not likely to ever
appear on Blu-Ray/SAT/Cable C.V. interfaces.
HDMI/DVI (and similar new I/Fs) are ONLY way to convey protected 1080p:
http://www.cepro.com/article/cea_puts_kibosh_on_1080p_over_component
holl_ands
=================================
Barry Wilkins <barry.barrywilkins@xxxxxxxxx> wrote: Hi Richard,
I am sorry if any of my previous email was confusing. Firstly, my screen is a
Philips 42" Plasma model 42FD9954/69C with DVI but no HDMI. It is not the
screen but the STB that does the down scaling on component output which was
forced upon the Freeview consortium by the HDCP powers. (If no HDMI input with
HDCP on the screen then 576i via component output only.) Do you have this
restriction there?
I am not saying that the image will not look better on a native 1920 x 1080
plasma/LCD if perhaps it was a really "good" screen. It is just that the only
screen that I have been able to compare mine to that actually does use the HDMI
input, from the same type STB, running the same demo programme, looked markedly
inferior. (mainly motion artifacts but lacked general clarity) My only
explanation for this is that the 42" LCD in question must be an inferior model
although the pixel size looked fairly fine. The shop I viewed this in had no
statement of the screen resolution.
Why am I having such difficulty in viewing the HD content on suitable
reference screens you might ask? Answer: Because strangely, very few retailers
of high end screens show much interest in Freeview HD. I tell them they must be
nuts to turn down a perfect opportunity to demo the capability of their high
end stock but they look at me lamely and say "Not company policy" or "We might
when the STBs become available" or some other idiotic reason.
I've been expecting to be blown away by the sheer difference in image quality
of the latest screen technology coupled to the HD broadcasts but so far my
screen is pretty much up with the best. My screen does lack high contrast ratio
compared to the latest models but I do not oversaturate colour and keep the
brightness at a respectable level.
Barry Wilkins
On Mon, Apr 28, 2008 at 2:00 PM, Richard Hollandsworth <holl_ands@xxxxxxxxx>
wrote:
What is manufacturer & model number of your 1024x1024 HDTV???
How do you know it downscales 1080i to 576i?
holl_ands
==================================
Barry Wilkins <barry.barrywilkins@xxxxxxxxx> wrote: To complicate this issue is
the fact that my screen is only 1024 x 1024 42" with no HDMI. I use the
component inputs from the STB which down scales the image to 576i.
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
Other related posts:
