Re: When is HDTV due out?

[Bob Myers <myers () fc hp com>]

Shigeki Misawa (misawa () physics16 berkeley edu) wrote:
> Er, I have a couple of questions about this "interim" broadcast standard.

> 1) Does this mean that HDTV over the airwaves and cable will be
>    using this interim standard during some "transition" period at 
>    the start of HDTV broadcasting, with the eventual goal of
>    broadcasting in the "final" format when the necessary
>    equipment comes "on line" ?

Exactly.

There are two things driving the need for a transition period under some
form of interim standard: first, we simply can't acheive 1920 x 1080 at
60 Hz progressive scan in any practical system today.  The cameras aren't
there, the receivers would be very expensive, and that's an AWFUL lot of
data to squeeze into a 6 MHz channel with existing compression technology,
esp. given the FCC's mandate that HDTV will coexist with NTSC for some time.

> 2) What effect does the interim standard have on receivers ?
>    Will people that buy interim HDTV receivers need to 
>    make a "hardware" upgrade to their TV to get it to
>    receive the final format? Who guarantees that the buyers
>    of interim TV's will actually be able to buy this necessary
>    upgrades ? Also, will these upgrades be "reasonable" in price
>    or will the consumer get "burned"?

This is not clear.  It may be perfectly possible that the first HDTV receivers
will be capable of receiving the final 1920 x 1080 proscan format, but will
display it in their own mode, whatever that may be.  It's pretty clear to
all how this would work with a 1920 x 1080 interlaced display; what's not
so obvious is that things could work just as well for a 1280 x 720 proscan
display, with a downconversion taking place in the receiver.  The final
image quality would be about the same in either case, since a 1920 x 1080
interlaced display doesn't really have any advantage over 720-line proscan,
and may actually be at a performance *dis*-advantage!

> 3) How will use of the "final" broadcast format be enforced?

The FCC has mandated a transition period during which HDTV and NTSC will
coexist; this is expected to be at least until 2008.  That gives at least
one logical point where the move to the final format might logically be
required, if it is practical by that time.  However, there really ISN'T any
clear plan for the transition right now, and many fear that a transition
format would remain entrenched for all time - bad news if the transition
standard is the wrong one.

>    One would think that broadcasters and equipment sellers would
>    be reluctant to use the final broadcast standard if it
>    will require additional capital investment or added cost
>    to the final product. (I.e., assuming that the HDTV thing
>    does catch on, what will prevent it from "getting stuck"
>    at the interim broadcast format?)

Well, one of the nice things about being digital is that all the pieces of
the system DON'T have to remain in tight lock-step, as has been the case
with the analog standards.  If the receivers are flexible enough right from
the start, and if the standard requires that the digital broadcast includes
headers & descriptors (which would tell the receiver such things as the format
of the data to follow, etc.), it is perfectly reasonable that stations would
"upgrade" when they can, driven by market demand.  But unless this IS clear
and included right from the start, you're right - we could get stuck!

> Looking at it from the perspective of a cynic, this multiple format
> system seems to be a great way to kill HDTV. There seems to be 
> numerous places where this whole process can be derailed, insert the
> normal FUD from the consumer perspective and voila, instant status quo.

Actually, if correctly implemented, a system allowing a hierarchy of related
standards and formats all under the same OVERALL standard could be one of
HDTV's biggest boons!  For example - why wouldn't you use, say, 512x288 for
a handheld "Watchman"-type display, if the standard can allow for a receiver
to do this?  


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers () fc hp com    Fort Collins, Colorado   |sentient life-form on this planet.