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Re: HDTV



<< All the discussions about HDTV formats are terribly interesting, and I am
 reading them all with great interest. Can I, however, ask you all one
 question.
 
 Do you think there will ever be significant broadcast HDTV services? >>

I think a lot can be learned from the experiences of FM radio and NTSC color
TV.  In both cases, the services languished when initially offered; nobody
wanted a FM radio when all you could hear on it was simulcasts of AM radio
programming, and there wasn't much incentive to buy a color TV when most
programs were still black-and-white.

Stereo and a FCC ban on simulcasting forced FM stations to develop
"alternate" programming.  Turning it into an entirely new and different
service allowed it to take off, and several years ago it surpassed AM
completely.  Color TV in America received its biggest boost in 1960 when
David Sarnoff (president of RCA and NBC) acquired Walt Disney's extremely
popular program from ABC, where it had been broadcast in black-and-white.
 Shaped into "Walt Disney's Wonderful World Of Color" it made color
television something no self-respecting household could be without.  

It would appear that digital TV learned something from these lessons in that
it is capable of offering not just more, but very different services right
off the bat. The system itself is a lot like Internet protocol; its job is to
send out multiple streams of data packets, each having its own packet ID
(we'll be hearing a lot about these "PIDs" in the future, I'll bet).  So a
broadcasting station could be sending out a high definition image signal or
two, maybe a few standard definition signals, a dozen CD-quality digital
audio channels, and a whole lot of other unrelated data all at the same time.
 Each receiver will respond to the data from the PIDs it is capable of
handling and ignore everything else.  

Now anybody who tells you that the first "standard def" digital TVs will cost
no more than analog ones is probably being overly optimistic, but such sets
will catch on because they'll look a lot better than analog TV (about the
equivalent of delivering a decent baseband NTSC or PAL signal right to the
viewer's home), and will get a lot more channels.  True high definition TV is
going to cost more, so it probably won't make its appearance so soon, but as
long as broadcasters and cable operators use it for programming that is not
available on standard def, it should get off the ground too, particularly
since higher grade TV sets are supposed to be able to access the lower
definitions as well.

The use of PIDs also makes the system obsolescence-proof to a degree.  New
services can come along, and they will have new PIDs which will simply get
thrown into the data stream with everything else.  Existing sets will
continue to work with existing services they can still decode; adapters,
modifications, or new sets would only be required to get the new services.
 Will the 18 possible programming formats that have already been identified
all survive?  Will we have to buy two or three (or 18) different TVs to be
able to see all of them?  Or will program delivery via the Internet become a
reality and blast the existing broadcast TV structure to smithereens?  Nobody
knows, but it sure looks like it ain't gonna be boring!

So I suspect that at least initially there will be some confusion and some
reluctance to invest in new equipment on the part of consumers.  On the other
hand, a lot in this standard deliberately favors broadcasters and cable
operators -- particularly where they can rent some of the bandwidth for
non-video data applications that exist right now.  So I'd expect these
facilities to get built pretty quickly even though a full conversion to
digital costs more than most present-day TV stations are worth!   

As an aside, the new DTV standard calls for each station to handle 19
megabits/second in a 6 MHz channel -- quite a step up from the 28.8 or 33.6
kilobits/second of a current computer modem, but no match for a D-1 or D-2
data rate, especially if a station plans to send more than one data stream at
a time.  So it is obvious that there is going to be a lot of compression
going on, and the requirements for most programming probably won't be as
extreme as what we  consider "high definition" in a production and post
production sense.  So don't put that old telecine out to pasture just yet!

Christopher Bacon
DuArt Video