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Re: HDTV WHY???
- To: telecine at sun.alegria.com
- Subject: Re: HDTV WHY???
- From: KA2IQB at aol.com
- Date: Mon, 29 Sep 1997 15:41:48 -0400 (EDT)
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At the New York SMPTE meeting last week, which was dedicated to digital disk
recorders, the subject of HDTV came up. A few of the remarks were relevant
to this discussion, so ...
Two of the three manufacturers said that they could do HDTV by paralleling
their current designs, which seems to be an industry-wide approach, by the
way. But since six times the number of bits for HDTV = six times the bucks,
there haven't been many takers, also an industry-wide trend. Actually only
one HDTV DDR has been sold so far, and that was to CBS.
All three seemed to feel that HDTV broadcasting is a long, long way off (if
ever). In fact, one of the three pointed out that even the 18 MHz/360 MBit
version of good old ITU-R/BT.601may not go very far. Why pay for a whole new
layer of incompatible equipment when it's only going to end up making the
data compressor at the TV transmitter work harder and probably not look any
better at the receiver?
I think those who say HDTV has to come no matter what the public says or
wants are missing one very important point: the laws of physics are not
subject to anybody's hopes or dreams. If you're going to economically cover
the maximum possible service area with terrestrial broadcasting, there's only
so much data you can pack into a channel. That magic number is 20
megabits/sec, which has to be shared between audio, video, and any anciliary
services a TV station wants to offer. Now compression algorithms may get to
be very much more clever than they are now, and the hardware will surely
improve, but beyond a certain point, there is only so much you can expect
from one-fourteenth the bandwidth of a D-1 VTR. If after all is said and
done and super-compressed HDTV looks about the same as moderately compressed
525/625, nobody is going to invest six times more money on HDTV.
Indeed, the opposite might be what actually happens: given the fact that
those same 20 Mbit ATV channels can be used to carry several
standard-resolution TV signals simultaneously instead of one HDTV signal,
more money may be spent on 525/60 and 625/50 formats in the future than ever
before. Somebody might have to make a bunch of new programming to fill all
those channels up!
Maybe HDTV would have half a chance if satellite and cable operators could
afford to do as they pleased. Or if the FCC allocated more spectrum space to
fewer TV channels. But the satellites and cable companies are stymied; the
industry is still primarily broadcast-oriented. Politicians have already
balanced future federal budgets on anticipated revenue of future sales of
existing TV channels, so the possibility of wider TV channels bigger is nil.
Channel data rate limitations won't exist to nearly to the same degree as
they do now if the FCC allows for many more low-power TV transmitters to be
built to improve the signal-to-noise ratio at receiving antennas. Just as is
the case with computer modems, the better your "connection," the faster you
can run before the error rate catches up with you. But they won't be able to
take this step until 2006 or beyond because of problems they're already
running into with digital TV interfering with the existing NTSC services.
To those who say, "look what happened in the case of FM," or "look what
happened in the case of color TV," I say, "look what happened in the case of
AM stereo!" Just because we can do something, and even find somebody to
invest in it, doesn't mean consumers will buy it. There has to be a reason
first. If that reason can be supplied, great, we'll all be high def by the
time we retire. But if nobody comes up with a valid reason (reasonably
priced equipment that works, in conjunction with programming that is worth
buying the equipment for), then I'd expect television to evolve to a digital
version of what we have now, and stop there.
As an aside, I am about the exact opposite of a "videophile." My entire
inventory of household video equipment consists of a 1969-vintage General
Electric "portacolor" TV (tube version), a "high tech" Zenith 19" System 3 TV
from 1977, and a 1982 JVC top loading VHS deck. Plus two black-and-white
antiques, a 1946 RCA 630TS, and a 1949 Admiral 5" set that has been in the
family since it was new. But this motley bunch of video detritus is mostly
pushed aside in favor of a collection of 16mm and 35mm sound film projectors
with all the necessary auxiliaries, and a healthy assortment of vintage
titles to watch. My take on "home theater," and it didn't cost anywhere near
the price of a HDTV receiver, nor did I have to wait for it!
Thanks to Michael Mazur for support of the TIG
TIG subscriber count is 855 on Mon Sep 29 12:41:55 PDT 1997
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