"Doug McDonald" wrote in message
...
R. Mark Clayton wrote:


Like we had quadriphonic radio broadcasts in the seventies. I would
guess that more than 99% of broadcast TV in the US is 525 line.

Nowhere near 99%. Prime time is about half true HDTV. Prime time
is 1/8 of the day, so 1/2 of 1/8 is 1/16, which is 6%. There
are also HDTV broadcasts outside prime time, including much sports,
including at some time on Sunday as many as 10 different
HDTV broadcasts, one afternoon soap opera (yes, I know),
and Jay Leno, soon Letterman too.

Now cable and satellite are probably much closer to 99% LDTV
(LDTV means worse resolution than NTSC.)


Er you seem to be rubetting and accepting my point at the same time. There
are loads of channels in the US (EU too), but just what percentage of the
overall output is HDTV? 1% I would guess. Is CNN HD? NBC, CBS your local
station etc.

Well dream on. More likely that the Europeans (these days tending to
include the French) will get it right.

Come to you senses, come to America, and look at our HDTV.

We have it too, though not much yet.


BTW France Supervision did some trial broadcasts using DMAC in the mid
nineties - very realistic pictures.


Your jaw will fall off.

Doug McDonald

No, although I have quad preamps picked up at an RSGB show for 80p. The
point was that these were on the QS? standard that was never adopted. I
likewise suspect that the US HD system will be superseded quite soon.

The only thing I see happening in the near future with US HDTV is
migration to 1080p instead of 1080i. By "near" I mean decades.

Eric

In message
Doug McDonald wrote:

Out of interest, which U.S. City benefitted from a regular off-air
television broadcast service using electronically sourced pictures
before November 1936 ?

None ... that's what I said. Can you read?

Show me where your word "None" appears in the paragraph you wrote below,
and which I replied to :

I realize that you had a small "official" broadcast
effort in one city in what, 1936. But you did not
actually get the electronic part done right before
the US.

G.

--
http://www.rat.org.uk gareth at lightfox dot plus dot com

"Gareth Rowlands" wrote in message
...
In message
Doug McDonald wrote:

Out of interest, which U.S. City benefitted from a regular off-air
television broadcast service using electronically sourced pictures
before November 1936 ?

None ... that's what I said. Can you read?

Show me where your word "None" appears in the paragraph you wrote below,
and which I replied to :

I realize that you had a small "official" broadcast
effort in one city in what, 1936. But you did not
actually get the electronic part done right before
the US.

G.

--
http://www.rat.org.uk gareth at lightfox dot plus dot com


Well, if you are ever in Schenectady, NY, feel free to visit the Palace
Theater, where GE's late 1930's TV hardware is on public display (not
functioning mind you). That city started TV in the States, although there
were very few people who could see the broadcasts.

Richard.

In message
Richard wrote:

Well, if you are ever in Schenectady, NY, feel free to visit the Palace
Theater, where GE's late 1930's TV hardware is on public display (not
functioning mind you).

Thank you. I have friends in the Broadcast industry living and working
in the NYC area, and would welcome the chance.

I must admit to being somewhat intrigued by your statement that NTSC
"provides more accurate color".

Can you enlighten me as to which specific aspect of PAL encoding is
responsible for providing 'inaccurate color' ?

Thanks,

Gareth.

--
http://www.rat.org.uk gareth at lightfox dot plus dot com

Gareth Rowlands wrote:
In message
Richard wrote:

Well, if you are ever in Schenectady, NY, feel free to visit the
Palace Theater, where GE's late 1930's TV hardware is on public
display (not functioning mind you).

Thank you. I have friends in the Broadcast industry living and
working in the NYC area, and would welcome the chance.

I must admit to being somewhat intrigued by your statement that NTSC
"provides more accurate color".

Can you enlighten me as to which specific aspect of PAL encoding is
responsible for providing 'inaccurate color' ?

Thanks,

Gareth.


Reluctantly entering the fray...

Equal-band color subcarriers? Certainly arguable, since I'm pretty sure
all modern NTSC sets use equal-band decoding.

In any case it's not fair to say 'inaccurate' as much as 'theoretically
less accurate', since neither system is all that 'accurate'.

NYC to Schenectady is roughly London to Manchester, BTW

--
Jim

"J.Michael Davison" wrote in message
...

"Doug McDonald" wrote in message
...
But, of course, PAL was simply infeasible as a consumer
technology in 1950-1953 when color TV was developed ...
and we note, NOT developed by Europeans, who simply
adapted the ideas of the Americans (even, of course, SECAM,
which used a subcarrier and split luma-chroma rather than
actual RGB).
Eh !
ALL monochrome compatible colour TV systems use split luma-chroma with the
chroma carried by a sub-carrier system.
Monochrome compatibility was the cornerstone of NTSC, PAL and SECAM so
black
and white TV owners were not denied a TV service. Frame sequential RGB
systems were not deemed to be compatible or practicable for that matter.
Mike Davison.

Trivial, perhaps: The US NASA used a color-wheel system for some of the
Apollo TV transmissions from the moon. I don't know if it was frame
sequential
or field sequential -- I thought field-sequential.

In article ,
Doug McDonald writes:
R. Mark Clayton wrote:


Like we had quadriphonic radio broadcasts in the seventies. I would guess
that more than 99% of broadcast TV in the US is 525 line.

Nowhere near 99%. Prime time is about half true HDTV. Prime time
is 1/8 of the day, so 1/2 of 1/8 is 1/16, which is 6%. There
are also HDTV broadcasts outside prime time, including much sports,
including at some time on Sunday as many as 10 different
HDTV broadcasts, one afternoon soap opera (yes, I know),
and Jay Leno, soon Letterman too.

During my recent visit to the UK (just returned today), I realized
that even our HDTV (16:9) shows are NOT necessarily shown in 16:9 and/or
PALPlus in UK.


Come to you senses, come to America, and look at our HDTV.

Your jaw will fall off.

PALPlus looks okay (on 100Hz TV), but it is far far far from HD. I had
also noticed that the 100Hz TV showed obtrusive scanlines (even small
screen, Loewe TV), yet I don't see a visible scanline on my own TV,
even displaying NTSC on the HDTV. Any kind of artifacting, including
visible scanlines, helps to confuse or distract the human vision system.

The flicker still persists (on 50Hz TV sets), but the 100Hz display
(perhaps imperfect, however) makes the PAL video look generally better.
My travelling companion (a co-worker) initially thought I was very
wrong about the 'flickerfest' problem until I informed him that our
hotel (Aztec in Bristol) seemed to provide each of us with 100Hz TV sets.
Initially, I was somewhat worried about my reputation when I looked at my
first true UK TV set in 21yrs, and it took a few minutes (1-2minutes) for me
to realize that it was a 100Hz TV. Star Trek, Next Generation (even with
NTSC composite 60i post production), didn't really look bad. Apparently,
they took advantage of NTSC 3D combing to remove the NTSC artifacting,
and did a good quality conversion. To me, the TNG broadcasts looked
little different from pristine NTSC reception of the same thing using
my HDTV.

Perhaps the worst case that I saw was a transcoded King of Queens. It
looked horrendous, perhaps even worse than the early Dr Who looked
here. (Given that show is done in 24p, and that looked like a moderatly
current episode, then there is NO excuse for artifacting other than doing
something silly like
24p(original) -- 60i(US submaster) -- 50(i/p) (broadcast)-- 100i (tv)
There is almost NO excuse for using a 60i scan in the process.

Also, some morning news shows are done in PAL, and the conversion
to digital is done without 3D comb (there aren't any commodity PAL
3D combs, however a few SPECIALTY devices.) The color flashing even
on non moving subjects still persisted, even on the digital version.
In the US, the concept of providing a moderately high end, composite
`video analog capable TV set without a 3D comb would result in almost
a totally failed product.

John

In article ,
"R. Mark Clayton" writes:

"Doug McDonald" wrote in message
...
Richard wrote:

Indeed, and it is uncorrectable if it's a differential phase errro,
which
is why NTSC is so crap.


snip

The NTSC system of that day DID require that the equipment with its
myriads of overheated vacuum bottles (and no feedback!) be kept
in tune ACTIVELY ... meaning that somebody had to check it. That was
the only actual problem ... PAL would have allowed sloppiness
to be covered up.

No PAL was designed so that such active adjustment was not required.

For a valid, simple datapoint: I was just watching a few TV
shows over the last week (in the UK), and was appalled at the
color accuracy, esp wrt flesh tones. I saw more green faces
on the 100Hz Loewe TV set than I have seen in the US in the
last year :-). The variation in skin tone was quite dependent
on the TV show, and the variation is worse than I have recently
seen on consumer NTSC TV sets.

It is obvious that the idea that you don't "have to worry about
color" has devolved into the idea that one doesn't have to check the
adjustments on the studio cameras.

Which is better: a system that was susceptable to color shifts,
production engineers are always concerned about color quality, but
the electronic problems that caused them had been stabilized
until it isnt a problem or instead, a system that can deal with some
color shifts (hiding phase shift problems), yet not worry about
basic quality control at the origination. I believe that one
TV show where I saw excessive shift in face tone was gmtv.

Truly, the 100Hz TV makes PAL50 viewable, and most of the
"artifacting" *might* result from better ability to perceive
the defects because the visual system isn't having to filter
out all of the flicker. I might have seen some double image
issues. One odd thing: that wierd, fuzzy look of non-US
'football' games persisted into SOME of the games on TV
in the UK. They also (SOMETIMES) see those fuzzy images!!!

For a real buzz (even though I HATE Am.Football) is to look
at a good 1080i rendition of Am Football games with all of the
crowd shots.

John

In article ,
Gareth Rowlands writes:
In message
Richard wrote:

Well, if you are ever in Schenectady, NY, feel free to visit the Palace
Theater, where GE's late 1930's TV hardware is on public display (not
functioning mind you).

Thank you. I have friends in the Broadcast industry living and working
in the NYC area, and would welcome the chance.

I must admit to being somewhat intrigued by your statement that NTSC
"provides more accurate color".

PAL TV sets just cannot give an accurate green (period.) Claiming that
NTSC is perfect would be wrong, but it is amazing when you do an a-b
with a closer-to-NTSC phosphor gamut. On phosphor based displays, the gamut
issue is problematical with practical, safe, low cost phosphors. On
filter based designs, I suspect that there is more freedom.


Can you enlighten me as to which specific aspect of PAL encoding is
responsible for providing 'inaccurate color' ?

Actually, the fact that PAL isn't as completely decoded as NTSC
kind-of makes those color flashes more likely (which even appeared on
some apparently digital broadcasts due to BBC not using their cool
3D comb and/or not using component instead of composite in critical
parts of the infrastructure.) That kind of color flashing artifact
provides an essentially TOTAL FAILURE on the section of the scene.

Perception-wise, color on NORMAL scenes, assuming non-3D comb solvable
situations, NTSC and PAL aren't that different. As technology is improved
(e.g. motion prediction or equivalent is included to allow 3D combing
to work on PAL50), then NTSC decoding will also be improved. The
major hole in coming with 3D combs on NTSC is that the decoding drops
to the level of 2D comb on the portions of the scene that change too
much.

(The advantage of 3D comb isn't just related to color, but
the luma detail is also higher because of the elimination of the diagonal
detail problem -- essentially chopping off the diagonal detail at around
the chroma subcarrier frequency. Other, non color aspects of 3D combs is
off topic, however.)

John