🚀 go-pugleaf

billd@fps.com (Bill Davidson) writes:

[ To Glenn, who said that NTSC pix are ok, it's the signal quality that bites ]

>I disagree completely.  Resolution is sickly compared to what it could
>be.  Have you ever seen a high resolution screen?  Laser disks are as
>good as it gets on a regular TV but the resoulution is still pitiful.
>The pixels are huge and there's no signal that can possibly fix that.
>Maybe I'm spoiled by looking at 1000+ line computer screens so much
>(I'd like HDTV to be even higher resolution but that would *really* be
>expensive).

You're spoiled. Think about what HDTV is going to get used for: NOT for
computer graphics. It will be BROADCAST and nobody in his right mind is
going to need to broadcast 24 bit megapixel to the general public....

Don't ask broadcast television to transmit N pixels of RGB, because it won't.
It transmits real world images which do not have a pixel resolution, and does
pretty good job if the signal is intact. These pictures also don't change
colors very fast the way graphics can, and NTSC was designed to exploit both
that and the inherent color resolution of our eyes. Once you get used to
megapixel displays, you really do notice the fringing on NTSC but IMHO it is a
small price to pay for the picture quality you get for the price in both
circuitry and broadcast power.

I agree with Glenn. The key is preserving the NTSC signal quality, improving
the color synchronization, and expanding the picture to cinema size. A
standard with these features will gain instant acceptance from its market
and is feasible to implement. Transmitting RGB quality pictures is expensive
and pointless because your picture quality will get nuked right away anyway.
The other nice thing about low resolution on NTSC is that it is robust against
noise. RGB video that normally requires shielded cable is not.

[ Glenn wrote this ]
>>  I commend the FCC for requiring that the new format signals be backwards
>>compatible, but I think that the standard could easily offer more than just
>>backwards compatibility.

>How long do we have to carry around the baggage of a standard that was
>designed so long ago that it can't even get the colors right most of
>the time?

That's because your TV's color decoder sucks or the signal was recorded
by a lousy camera. If you continue to insist that television deliver
workstation quality color graphics then I suggest you invent a new standard to
implement it, because HDTV will not be used for graphics by most of its
intended market.

> Color was an add-on and the implementation suffered in order
>to maintain compatibility with old black and white sets.

Oh? How would you have done it? You forget the installed base of black
and white TV sets, and the inherent cost difference which causes b&w sets
to still be manufactured and sold to this day. There is also transmission
bandwidth to consider.

> At some point
>you have to say "enough is enough".  We can do so much better now.  We
>know a lot more about video signals than we did when NTSC was designed.

Very true. But what you are suggesting is impractical overkill that gratifies
graphics purists and is engineering hell to the standards committee.

>Also, the frame rate is annoying.  It destroys resolution when
>converting 24 frame/sec film to video due to frame mixing.  I want a
>standard with at least 1000 lines and a 72Hz frame rate.  Wide screen
>would be nice for films and square pixels would be nice for computer
>graphics.

Your frame rate is a good idea, because the primary benefit of HDTV will be
movie quality video rentals and cable. I don't know if a full 1000 lines
would be required, and I somehow doubt it. 800 sounds ok for a wide picture
but I'll defer to the movie experts.

Where do you get square pixels? You're practically asking them to define an
exact display and graphics transmission standard along with it! Who's going to
use that, besides Pixar and Apple Computer?

> Why suffer with the old forever?

Because it addresses the realities of its intended use much more effectively
than what you're suggesting could ever hope to.

> Just because most people
>won't be able to afford it is rediculous.  Most people couldn't afford
>pocket calculators when they first came out (or TV's, or cars or most
>other major new technologies).

No, it's the installed base. You can't just tell them to buy new boxes because
they'll tell you go screw. After all, if you talk them into paying you for a
whole new set of equipment, couldn't you just do it again in 20 years when this
standard is 'obsolete'?

> We need to define a standard that is
>good and is doable and which can be foreseen to become cheap with time.
>It doesn't have to be cheap now.

Yes it does. We want movie quality television, more or less cheap, and now.

> It would be nice if it was an
>international standard as well so that video tapes and laserdisks will
>work anywhere.  It took CD's 5-6 years to really break into the US market.
>A lot of people thought they were rediculous when they first became
>available.  They were very expensive (both the players and the disks).
>Now it's getting hard to find records stores that have more vinyl than
>aluminum coated plastic.  It took laser video even longer (it's back
>and gaining a lot of momentum right now).  HDTV will be the same story.

No it won't. You just mentioned some storage mediums, which are dislpayed
through cables to a monitor nearby. These can have almost infinite quality
because the wires are shielded and the signal quality does not degrade.
As soon as you broadcast via radio, you have many engineering restrictions
on your picture quality; NTSC addresses them very well regardless of its age as
a standard. It does lack signal correction, but for many people the improved
quality and wider screen will make them happy campers.

>We have generations of people now who grew up watching TV and they are
>getting more and more demanding of quality video.

They can get it from a laser disk, or on their computer's monitor. In the world
of broadcast television it will end up more like Glenn's idea, because without
signal correction all the resolution in the world won't look much better than
NTSC anyway, especially when you start throwing noise and ghosts and other
radio phenomena at the signal.

The basic point I'm making is: there's a fundamental difference between your
monitor cable and a radio transmitter. You can't get the quality of a shielded
cable from a radio transmission unless you use very good error correction and
even then it takes a lot of power and bandwidth to transmit. I can see a few
special purpose channels to do this but for consumer television it is simply
not worth the cost.

What you want deserves its own standard. The quality you'd like to see cannot
be broadcast cost-effectively so why not declare it to be only for storage
media and then go all out on the picture quality: 24 bit color, 2Kx1K pixel,
CD-ROM or better error correction, etc..

But please do not ask anyone to figure out how to transmit it via radio. Its
time will come when cable and fiber optic networks become the standard means
of communication. Until then, 'NTSC on steroids' will be the better choice for
movies and television.

Todd Whitesel
toddpw @ tybalt.caltech.edu