[opendtv] Re: source programme quality
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sun, 27 Apr 2008 20:06:25 -0400
Barry Wilkins wrote:
> The situation here to start with is that we have a mix of SD
> at 576i, HD at 720p and HD at 1080i source content. This is
> all transmitted as either 720p or 1080i via upscalers where
> needed.
Hi Barry. Here are my observations as a viewer (not a broadcaster):
My new LG TV tells me in what mode a broadcast is being transmitted.
Assuming it is correct, all of our programs here are *not* upconverted,
as yours appear to be.
Typically, but not always, the -1 subchannel of each multiplex is
transmitted as 720p or as 1080i, and the program content may be HD or
upconverted SD. The other subchannels are typically transmitted as 480i.
It appears to be that when SD content is upconverted, it is transmitted
as 4:3 rather than 16:9, just judging from the detail in the image. It
seems that all true HD content is 16:9. (One of our local stations
transmits five 480i multicasts only, nothing upconverted.)
> Some supposedly SD source material can look exceedingly
> good, i.e. better than my best looking PAL SD dvd from my
> collection.
Certainly has been my experience here as well. And some SD looks very
similar to analog TV broadcast, minus the ghost. It's strikingly bad
compared to other SD material.
> The HD source material at 1080i, i.e. Boston Legal for
> instance, is extraordinarily good imagery. So is some
> Aussie HD content.
>
> 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.
> Nevertheless, I can clearly differentiate between the
> better image quality on my screen and that of a 42" LCD
> connected directly via HDMI to the same type of STB
> running the same demo HD programme content.
>
> What I am getting at here is that in 3 weeks of looking,
> I have not been able to find a demonstration of HD
> source material received on a STB connected via HDMI to
> a 1080 x 1920 resolution LCD/plasma screen that improves
> over what I am seeing.(And I am delighted in what I see).
> If and when I do see a significant difference from a
> better screen set-up I shall be "over the moon" knowing I
> can make a difference by upgrading the screen later..
I believe it. Your LCD panel should be more than adequate. If I
understand what you're comparing, you have determined that OTA HDTV, via
HDMI, on a 1024p panel is about as good as OTA HDTV on a 1080p panel.
First off, tests in the past have shown that 720p and 1080i are roughly
comparable in quality. So, if you find that converting either of these
to 1024p (1.05 Mpel) gives results similar to converting to 1080p, I
wouldn't be a bit surprised. IMO, if there's any reason to go up to 1920
X 1080 in a 42" display, it would be to view BluRay disks, from a 1080p
player, up close. For broadcast TV, shouldn't provide any meaningful
improvement.
There is a small difference, though, that I have noticed. In comparing
1366 X 768 (also 1.05 Mpels) to 1080p panels from the same manufacturer,
and standing close in, concentrating on brightly lit parts of the scene,
the 1080p screen looks smoother. In the 768p screen, standing close, you
can see individual pixels more readily. I pointed this out to my wife,
and she noticed it too. But at normal seating distance, with the 42"
panel, the individual pixels disappear. Exactly as the math says they
should.
> Also, what HD I see is easily better than the quality of
> image viewed at any of the local cinemas. So what has
> been the general impression of the image quality of the
> best ATSC content. Are you all very impressed? How close
> does it get to Blue Ray quality at 1080i? What screen
> resolutions are you viewing this on?
I've been impressed ever since first seeing HD in stores. Most people
are, as far as I can tell. Most comments I've seen are that live sports
are especially impressive as HD.
Bottom line: I always take negative comments from habitual critics with
a huge grain of salt.
Unrelated example: last night, we went to see "88 Minutes," with Al
Pacino. It got some pretty bad reviews, but we went in spite of these.
Well, it was a great movie. Plenty of suspense, perfectly fine acting. I
have no idea what drug those moron critics were on, but no doubt they
will dissuade many people from going to see it. Their loss.
Bert
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