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European HDTV - 720p or 1080i

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Anonymous
October 28, 2004 10:50:13 AM

Archived from groups: alt.video.digital-tv (More info?)

<http://www.tvtechnology.com/features/news/n_HDTV.shtml&...;

Sony:
"Movies, entertainment, kids, current affairs, docs and even
sport all work wonderfully well in interlaced form. 720p
will be a detour, not a migration."

Panasonic:
"The longer term trend is towards progressive production and
distribution. We believe it creates the best pictures for
the consumer."

Kirk Bayne
alt.video.digital-tv Home Page
<http://www.geocities.com/lislislislis/avdtv.htm&gt;
Anonymous
October 28, 2004 3:55:14 PM

Archived from groups: alt.video.digital-tv (More info?)

K. B. wrote:
> <http://www.tvtechnology.com/features/news/n_HDTV.shtml&...;
>
> Sony:
> "Movies, entertainment, kids, current affairs, docs and even
> sport all work wonderfully well in interlaced form. 720p
> will be a detour, not a migration."
>
> Panasonic:
> "The longer term trend is towards progressive production and
> distribution. We believe it creates the best pictures for
> the consumer."

Who knows?

Most European HDTV production is 1080/50i or 1080/25p at the moment.
However many European HD facilities are based on Thomson (was Philips)
Worldcams (LDK6000 mk IIs) which have those clever 4000ish line CCD sensors
that can run in either 1080 or 720 (they group different numbers of
horizontal scanlines together)

I suspect 720p for transmission (even if not for production) has some
potential benefits for transmission using DVB-T in 7MHz countries, as it
requires lower bandwith than 1080i? There has also been one recent EBU
report suggesting that since most HD displays are likely to be progressive
in Europe (flat panels and most domestic projectors are likely to be LCD,DLP
or Plasma progressive, only CRTs support interlace natively) a progressive
transmission system may be a sensible move - though 1080/50p would be the
ideal solution to this... (If bandwith was no limiting factor of course...)

Steve
October 28, 2004 3:55:15 PM

Archived from groups: alt.video.digital-tv (More info?)

"Stephen Neal" <stephen.neal@nospam.please.as-directed.com> wrote in message
news:clqj6h$cfr$1$8302bc10@news.demon.co.uk...
> K. B. wrote:
>> <http://www.tvtechnology.com/features/news/n_HDTV.shtml&...;
>>
>> Sony:
>> "Movies, entertainment, kids, current affairs, docs and even
>> sport all work wonderfully well in interlaced form. 720p
>> will be a detour, not a migration."
>>
>> Panasonic:
>> "The longer term trend is towards progressive production and
>> distribution. We believe it creates the best pictures for
>> the consumer."
>
> Who knows?
>
> Most European HDTV production is 1080/50i or 1080/25p at the moment.
> However many European HD facilities are based on Thomson (was Philips)
> Worldcams (LDK6000 mk IIs) which have those clever 4000ish line CCD
> sensors that can run in either 1080 or 720 (they group different numbers
> of horizontal scanlines together)
>
> I suspect 720p for transmission (even if not for production) has some
> potential benefits for transmission using DVB-T in 7MHz countries, as it
> requires lower bandwith than 1080i? There has also been one recent EBU
> report suggesting that since most HD displays are likely to be progressive
> in Europe (flat panels and most domestic projectors are likely to be
> LCD,DLP or Plasma progressive, only CRTs support interlace natively) a
> progressive transmission system may be a sensible move - though 1080/50p
> would be the ideal solution to this... (If bandwith was no limiting factor
> of course...)
>
> Steve
No, No No! a 1080p60/1080p24 system would be the ideal solution!!!!!

Richard.
Related resources
Anonymous
October 28, 2004 3:55:15 PM

Archived from groups: alt.video.digital-tv (More info?)

Stephen Neal wrote:

>
> I suspect 720p for transmission (even if not for production) has some
> potential benefits for transmission using DVB-T in 7MHz countries, as it
> requires lower bandwith than 1080i? There has also been one recent EBU
> report suggesting that since most HD displays are likely to be progressive
> in Europe (flat panels and most domestic projectors are likely to be LCD,DLP
> or Plasma progressive, only CRTs support interlace natively) a progressive
> transmission system may be a sensible move - though 1080/50p would be the
> ideal solution to this... (If bandwith was no limiting factor of course...)


Uh ... Europe uses COFDM, and they claim that it is perfect.

Since it is perfect, then there should be no problem
in transmitting 1080@50p. Especially since you have 7 or
8 MHZ channels.

(Note that actually that is quite silly ... you should
make the plunge and write specs to allow instant, no
glitch format switches so you can transmit either
720p (for sports) or 1080@25p (for everything else)
at the switch of a bit.

Doug McDonald
October 29, 2004 7:12:52 AM

Archived from groups: alt.video.digital-tv (More info?)

"K. B." <hotmail.com@lis2lis2> wrote in message
news:418095d5.9056093@netnews.worldnet.att.net...
> <http://www.tvtechnology.com/features/news/n_HDTV.shtml&...;
>
> Sony:
> "Movies, entertainment, kids, current affairs, docs and even
> sport all work wonderfully well in interlaced form. 720p
> will be a detour, not a migration."

1080p ;)  The problem is most modern display technologies inherently favour
progressive material, so it either means a less than optimal conversion going on
in consumer kit or keeping the emissions purely in progressive then leaving any
conversions to worthy kit on the broadcasters side.

The latest EBU tech review discusses this in some depth :-
http://www.ebu.ch/trev_home.html


Az.
October 29, 2004 7:34:08 AM

Archived from groups: alt.video.digital-tv (More info?)

"Doug McDonald" <mcdonald@SnPoAM_scs.uiuc.edu> wrote in message
news:clqtcd$d5s$1@news.ks.uiuc.edu...
> Stephen Neal wrote:
>
>>
>> I suspect 720p for transmission (even if not for production) has some
>> potential benefits for transmission using DVB-T in 7MHz countries, as it
>> requires lower bandwith than 1080i? There has also been one recent EBU
>> report suggesting that since most HD displays are likely to be progressive in
>> Europe (flat panels and most domestic projectors are likely to be LCD,DLP or
>> Plasma progressive, only CRTs support interlace natively) a progressive
>> transmission system may be a sensible move - though 1080/50p would be the
>> ideal solution to this... (If bandwith was no limiting factor of course...)
>
>
> Uh ... Europe uses COFDM, and they claim that it is perfect.
>
> Since it is perfect, then there should be no problem
> in transmitting 1080@50p. Especially since you have 7 or
> 8 MHZ channels.

It depends how you slice and dice the payload of course, regardless of
modulation. Like some US outlets, Australia has taken to shoehorning an SD
stream into their multiplexes, so you have the 23Mbps throughput of a 7Mhz
channel having to also include what some could call an over generous 7-8Mbps SD
stream.

<
> (Note that actually that is quite silly ... you should
> make the plunge and write specs to allow instant, no
> glitch format switches so you can transmit either
> 720p (for sports) or 1080@25p (for everything else)
> at the switch of a bit.

20 year old Peritel connectors manage to do auto widescreen switching without a
problem :/ 

I think that's already the case, to certify kit it also has to be capable of
displaying 60i material :-
http://www.hdtvforum.org/en/the_forum/label.html


Az.
Anonymous
October 30, 2004 4:42:39 PM

Archived from groups: alt.video.digital-tv (More info?)

"Doug McDonald" <mcdonald@SnPoAM_scs.uiuc.edu> wrote in message
news:clqtcd$d5s$1@news.ks.uiuc.edu...
> Stephen Neal wrote:
>
>>
>> I suspect 720p for transmission (even if not for production) has some
>> potential benefits for transmission using DVB-T in 7MHz countries, as it
>> requires lower bandwith than 1080i? There has also been one recent EBU
>> report suggesting that since most HD displays are likely to be
>> progressive in Europe (flat panels and most domestic projectors are
>> likely to be LCD,DLP or Plasma progressive, only CRTs support interlace
>> natively) a progressive transmission system may be a sensible move -
>> though 1080/50p would be the ideal solution to this... (If bandwith was
>> no limiting factor of course...)
> Uh ... Europe uses COFDM, and they claim that it is perfect.

Err - what has the robustness or otherwise of a transmission system got to
do with bandwith constraints? I don't think anyone has ever claimed that
COFDM supports an infinite data payload. It DOES allow reliable reception at
very low transmission powers - which are a real requirement in the UK where
our UHF-only 5 channel analogue transmission system has very little space
for high power transmissions of new services.

At the moment the UK DVB-T scheme uses 4 16QAM muxes (BBCx2, Crown
Castlex2) - carrying 18Mbs each in an 8Mhz channel (less data than an 8VSB
ATSC 6MHZ channel delivering 19Mbs - but covering a significantly wider
transmission area for a given power) whilst there are also 2 64QAM muxes
(ITV/C4 and C5/SDN) which carry 24Mbs in an 8Mhz channel, but cover a
smaller transmission area for a given transmitter power.

16QAM should deliver a single 1080/50i picture at a reasonable quality, or
carry a 720/50p stream and a single 576/50i stream again at reasonable
qualities. A 64 QAM mux should carry a 1080/50i picture and 2 576/50i
streams at reasonably quality, or conceivably 2 720/50p streams though this
is pushing things a bit. (All this using MPEG2)

I think squeezing a 1080/50p picture into 24Mbs is pushing it - though by
switching to MPEG4 (which is a real possibility in countries that haven't
yet switched to HD so have no legacy HD receivers in situ) it might be
possible to do this - AND squeeze in an MPEG2 SD simulcast for
compataibility with existing receivers. AIUI the DVB/MPEG2 transport
streams allow for data to be carried (say as IP packets) which would allow
existing DVB (COFDM in the case of DVB-T) transmitters and existing
distribution networks to be used for this - and also allow existing boxes to
display an SD simulcast. (Though a simulcast might be deemed a waste of
bandwith I guess)

>
> Since it is perfect, then there should be no problem
> in transmitting 1080@50p. Especially since you have 7 or
> 8 MHZ channels.
>
> (Note that actually that is quite silly ... you should
> make the plunge and write specs to allow instant, no
> glitch format switches so you can transmit either
> 720p (for sports) or 1080@25p (for everything else)
> at the switch of a bit.

Surely 1080/50p is better than 720/50p for all material - so if you have the
bandwith (say on satellite) then surely 720/50por 1080/25p is just a
cop-out - especially given the availability of 1080p panels, and the poor
quality motion rendition of 25p systems. You could easily run 1080/50p
production and downconvert to 720/50p for OTA (where bandwith is an issue)
keeping 1080/50p for other delivery methods (satellite and digital cable)
There is no frame/field conversion required, just a basic scale - so not an
expensive conversion.

On-the-fly format switching (we have on-the-fly aspect ratio switching
already in the UK - though differing methods are used on DVB-S and DVB-T in
the UK implementation) is another option I guess - there is no point wasting
bandwith using 50p for 25p originated material (though I suspect most modern
encoding systems will be designed to detect repeated frames anyway). I
wouldn't want my 1080line stuff restricted to 25p motion rendition though -
I'd rather have 50i available as an option as well if possible.

Steve
Anonymous
October 30, 2004 4:42:40 PM

Archived from groups: alt.video.digital-tv (More info?)

Stephen Neal wrote:

>>
>> Uh ... Europe uses COFDM, and they claim that it is perfect.
>
>
> Err - what has the robustness or otherwise of a transmission system got to
> do with bandwith constraints?


It has EVERYTHING to do with it. See Shannon's law. The wider the
bandwidth, the more error fixing coding can be done, at a constant
final payload bitrate.



>I don't think anyone has ever claimed that
> COFDM supports an infinite data payload. It DOES allow reliable reception at
> very low transmission powers - which are a real requirement in the UK where
> our UHF-only 5 channel analogue transmission system has very little space
> for high power transmissions of new services.

It allows reliable reception at low powers only a LOW BITRATES.
At the same bitrate COFDM requires twice the average power and three
times the peak power of 8-VSB.



Doug McDonald
Anonymous
November 1, 2004 12:29:14 AM

Archived from groups: alt.video.digital-tv (More info?)

Doug McDonald wrote:
> Stephen Neal wrote:
>
>>>
>>> Uh ... Europe uses COFDM, and they claim that it is perfect.
>>
>>
>> Err - what has the robustness or otherwise of a transmission system
>> got to do with bandwith constraints?
>
>
> It has EVERYTHING to do with it.

Yep - but that wasn't the question you framed. You claimed that Europe
claims COFDM is perfect - I don't think anyone has ever seriously made that
claim.

> See Shannon's law.

I'm pretty familiar with Shannon's law - though I am no longer an active
engineer (I work in a non-engineering role in the broadcast industry these
days) I did a degree in Information Sciences with shedloads of information
theory...

> The wider the
> bandwidth, the more error fixing coding can be done, at a constant
> final payload bitrate.

Yep - exactly the reason the UK has moved to 16QAM from 64QAM for some
muxes - to allow the very low power levels we can run to be more usefully
deployed in the real world. The benefits of COFDM with respect to
multi-path are still also valid. I'm not starting the old 8VSB vs COFDM
argument again - we are where we are. I do get a bit annoyed by the "Europe
claims their system is perfect, aren't they stupid" tone of some posts here.
Whether 8VSB or COFDM is better is never going to settle - we live in
different broadcast landscapes. However COFDM is working pretty well over
here - and the UK's COFDM system has the highest penetration in terms of DTT
homes per capita of any country in the world AIUI? It may not be the best,
though most regions chosing DTV schemes seem to plumping for an OFDM system,
it may not be perfect, but it is working, and seems to be quite popular.

AIUI 1080/50p carriage should be possible within a standard 8MHz COFDM
service using a more capable codec than MPEG2 - though of course this is
true for ATSC. I guess the difference is that because Europe is going HD
later than the US we are able to chose a newer codec for use with HD with an
existing modulation scheme for transmission? (If the US were to move away
from MPEG2 for HD but still use 8VSB ATSC modulation there would be a lot of
redundant HD MPEG2 receiver out there...)

Steve

Steve
!