[opendtv] Re: 1080p @ 60 is Next?

  • From: Olivier Houot <olho_avatar_i@xxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Sat, 12 May 2007 02:24:41 +0200

Mr. Hoffmann,

first i have to say i like the EBU demo principle, especially the way the sources have been elaborated. I just regret the big screen behaviour has not been given due attention. It should not be dismissed out of hand, but tested, and the results should be an input to the final decision .

I don't mean that the difference between SDTV and HDTV is invisible on a 50 inch screen, i say that HDTV is primarily about having a bigger picture. As often mentionned on this reflector, the initial target was a 30° viewing angle.
Some NHK links on the matter:
http://www.dibeg.org/techp/Documents/Brazil010618/Attachment1-HDTV.PDF
http://www.nhk.or.jp/digital/en/technical_report/pdf/ibc200502.pdf

It would be impractical for people to sit close enough to a 50 inch panel to get this angle, but it has been also mentionned that people sit closer when the screen is bigger. Link to one such study :
http://www.tid.es/documentos/boletin/numero6_4.pdf

I don't doubt there are serious studies showing a trend towards such and such flat panel sizes here and now. But i will remark that HDTV front projector prices have been falling to mass market level in the latest years, which to me is an indication that many people are buying them too.


You can for example get a Sanyo PLV-Z5 for 1100 euros (french site, sorry)
http://www.magma.fr/?module=boutique&act=details&pid=1009689

Prices for flat panels on the same site :
http://www.magma.fr/?module=boutique&act=details&pid=1009689

The prices are close, but in the recent past , i remember panels to be rather more expensive than projectors on average.

Now the PLV-Z5 can project a 2.5m wide picture from a distance of 3.7m with the maximum zoom setting. With some more room for the body of the projector, we would be around 4 m. However, to view a 2.5m wide screen under an angle of 30°, you must be at 4.83 m. Allow some room for the back of an armchair, and you are at 5 m. So you need a minimum surface of 5 x 2.5 = 12.5 m2.

I've found a (french, sorry again) document regarding european housing statistics :
http://www.union-hlm.org/structu/m-europe.nsf/62569fb6fa5eb929c12566e20077b9ba/b6b27a4cd30cd8d4c1256875001bdd32/$FILE/statistiques%20logement%20UE.pdf

In France, for example, section 2.1 says the average surface is 88 m2, and section 2.2 that the average number of rooms is 4. That would be some 22 m2 per room, and we should keep in mind that the living room is often bigger than the others. But even a 20 m2 room could provide a 4 x 5 m arrangement.

The living room often tends to have a TV-centric organization. So i am not convinced people wouldn't be prepared for a little reorganization for such a big screen A 2.5m wide thing would be 2.5 *9/16 = 1.4 m high. If the ceiling is at 2.5m, you still have 1.1 m under it to put some waist-high furniture. The screen could be masked with some pretty curtain when not in use, or rolled up and would even leave 0.75 m on each side with a 4m wall (well, i guess you have to put the
speakers somewhere, if not under the screen).

Note that if you have less than 5m length available, you need the high
resolution even more. Of course, you can upconvert, but then you are not providing the eye of the observer with all the information he is able to capture.

I would point out once again to the possibility of having live events broadcast to public audiences either in digital theaters, or in village halls, where there are no such size limits . This is part of the business model of some companies like VTHR or euro1080/exq1. But there is no need for small villages to pay a subscription if public channels have sufficiently high quality for the purpose.

Also, i doubt that the people making the bulk of  flat panels statistics
are those leaving in the smallest appartments, considering the average price. Again this may be just a passing trend. If someone gets a chance to see a big screen movie at a friend's, what will he feel like when back in front of his own smaller, fixed-size, perhaps more expensive flat panel ? The friend may also come the next day with his projector under the arm to do a local demo. Try to move that bulky and fragile flat panel in the same way! As the years go by, a plasma panel will gradually lose its luminosity and picture quality. Nothing to do but to trash it and buy a new one. But the friend can change the lamp in his projector for a fraction of the price and enjoy it for many more years.
So perhaps, after the first enthusiasm, people will reconsider.

Also, there may be some disruptive technologies on the way : laser projectors which would be free of the limitations of current optics (we may aim for more than 30° then ), and always the possibility of having a virtual big screen using goggles. With the mobility trend, this concept may make a come back.

A serious broadcaster should invest money in a production tool that will outlive the passing trends, and will not force a renewal of the entire receiver base if some unplanned but predictable evolution occurs. it may make sense to broadcast 720p at the moment, but ideally the receiver should not go dark if a switch to 1080p is
decided later.

By the way have you heard that they are talking about 3D again ? Broadcasting in 1080p would make it easier to switch to stereoscopic 1080i in case of need . Ain't it nice? :-)


From: "Hoffmann, Hans" <hoffmann@xxxxxx>

Dear Mr. Houot,

this is a very interesting contribution to the discussion.

The reality is however that European homes will not cope the size of the
screen you propose.
Any broadcaster has to consider business aspects such as maximum needed
bandwidth for transmission (= money to pay). Consequently it important to
consider the "major population display size" in consumers homes. Any serious
broadcasters has also to consider that the major population are not "geeks".

If you buy some reports of GfK, displayserach etc. then you will find that
the major sales of display are in area of ~ 37 inch diagonal with an trend
to ~ 42 inch. The display we used with 50 and 52 inch were already above the
majority. We cannot expect that homes will become bigger, thus the space for
large displays (or even a wall/screen for projector systems) is rather
limited.

We have also seen that the TV experience with good HDTV on the screens we
used in the tests makes a difference to SDTV and in fact is appreciated by
the assessors. Please send me the scientific data which you have used for
your statements. This should be interesting.

In conclusion, I have to say that your arguments do not hold against the
results of the tests for TV broadcasting applications.

Hans Hoffmann




-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Olivier Houot
Sent: 10 May 2007 22:37
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: 1080p @ 60 is Next?


Those relatively small flat screens used in the EBU tests may be very trendy, but any self-respecting HD geek would only contemplate a picture with at least a 2.5 meter base.


Also, consider that some "live" events might be retransmitted in digital theaters on a cinema-sized screen.


I understand it would have been difficult to set up a demo with three 10 meters wide screens, but at least 2 x 2.5 m above one another could have been considered.


Big screens would be more revealing of resolution deficiencies, and the conclusions would have offered some security margins when applied to smaller ones.


I don't think the choice of the more appropriate standard should be based on the present market trends, especially in an industry where things can change so quickly.


Watching a 1.27 m screen (diagonal), even in high definition, does not fundamuntally change the TV experience. With a 2.5 m screen (width), it really begins to fell like you're at the movies.


A sizeable fraction of the early HD adopters have opted for a big picture (which means front projectors at the moment), and EBU should not make a choice that would clearly expose limitations in such viewing conditions.


Perhaps the final conclusions would not be very different, but at least the test should be made.


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