[opendtv] Re: Frames Per Second of 720P

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Sun, 27 Jul 2008 10:09:26 -0400

At 10:07 AM -0700 7/26/08, John Willkie wrote:
It's totally absurd to mention the deprivation of legacy receivers in this
context; it's like asking "how will color cameras affect black and white
television sets?"


The important question to ask in this content is what is being done to enhance the the ATSC standard for fixed receivers in the home? Or to be more precise, will broadcasters support any enhancement that will not work for legacy receivers?

Clearly, h.264 is a desirable enhancement for both the new M/H service and for fixed receivers. One must ask whether broadcasters will use this codec for full resolution HD broadcasts, knowing that legacy receiver will go black (or blue screen).

Let me give you an example that I can talk freely about.  When you shoot for
small screens, you "shoot bigger" than when you shoot for a large screen.
When shooting someone's face, you would tend to make their face fill more of
the screen than if you were shooting for a large, or even room-filling

This illustrates how out of touch you are John. My iPhone screen has more resolution than most NTSC displays. I seriously doubt that image capture and framing techniques will change because of mobile. By the way, I used to think that way about the web on mobile devices, until Apple solved the problem, making it possible to view ANY web page on a small screen.

But this does not prevent some content creators from building web pages optimized for small screens, just as there will be a new genre of short form video for mobile devices.

So, if you think that there's much utility in showing a screen-filling face
on a large, room-filling tv set, rock on. \

Apparently many directors of cinematography have no problem filling a movie screen with a face...

All standards are out of date in this time frame at the time they are
adopted.  But that's not the real problem with standards.  "I love
standards, there are just too many of them" is the real problem.  But,
thankfully, there is only one standard for digital tv transmission in the


The ATSC standard uses h.262 encoding for video.

DirecTV and DISH are using both h.262 and h.264 encoding for digital TV transmissions.

Apple is using h.264 for selling and renting TV shows and movies to the masses.

Others are using Windows Media for digital TV.

And Flash is being used by YouTube and others.

I guess John is just focused on terrestrial broadcasters, who now capture less than 1/3 of the digital TV audience (full day ratings, not just prime time).

And did I mention that the new ATSC mobile standard has competition too...

Back to the ESG (electronic service guide).  Wouldn't it be cool if the same
devices all over the world could employ the same bits to render an ESG?  If
that ESG would work over the web, over the air, and be usable on WiFi
devices, mobile phones, web browsers, wireless routers, etc. etc., and be
able to provide programming information on broadcasts, regardless of
modulation or channel coding?  There is already such an electronic service
guide system, and I could even talk about it without violating the ATSC NDA.
But I won't.  "Already" might be an exaggeration, but only by a few weeks or

I think Google is working on this...


If you think that 8-VSB is more efficient than a modulation scheme that you
know nothing about, one wonders about your sanity.  It seems to me that,
since the payload of any modulation scheme for tv is largely carrying video
(something like 95% or more of a program service is video) that the more
relevant figure is the efficiency of video compression and how that is
packetized.  I suspect that you don't mean to imply that MPEG-2 is more
bit-efficient than MPEG-4.\

Uhhhhh John...

8-VSB is significantly more bit efficient than any of the proposals for mobile/hand held. Depending on the constellation that will be used there will be an additional 25% to 50% bit penalty for the ruggedized modes of the mobile standard.

What I MEANT TO IMPLY - actually I clearly stated it - is that it would be possible to offer a movie download service that would deliver the bits using 8-VSB to maximize bits per hertz, and also use h.2645 for encoding, which would maximize compression efficiency relative to MPEG-2.

Obviously, no legacy receiver would be able to view these movies, but that's OK.

I said this in the context that some manufacturers will most likely build the new ATSC enhancements into their fixed receivers. This will allow these fixed displays to use all of the new services offered for the mobile/hand held market, and to decode h.264 bitstreams that can be delivered with 8-VSB, the M/H modulation, a DBS broadcast, cable in the near future, and Internet download. This assumes that the M/H standard will use h.264, which I believe to be a safe assumption at this time.

I doubt that a broadcasters would be concerned about the incompatibility of legacy receivers with h.264 bitstreams delivered using 8-VSB, if these bitstreams are a separate paid service like Moviebeam.

I think that it's unlikely that "new receivers 'may" be able to take
advantage of the new mobile bits to improve their ability to tune to any DTV
channel "  The ATSC M/H process had three different modulation/coding
schemes to consider.  I know not much about the Thomson proposal, and I
haven't bothered to look it up.  I know a bit more about the Harris/LG MPH
proposal, and I know quite a bit about the A-VSB proposal thanks to one R&S
engineer I talked to at NAB that provided me with an 8mb powerpoint
presentation.  (And, I've talked with several Samsung consultants over the
years that their proposal has been pending.)

What has ANY of this to do with the possibility that ATSC M/H features may be incorporated into future fixed receivers?

To the best of my knowledge, nothing in these proposals would have aided the
ability to tune into any legacy programming.  Indeed, if we are talking
about the early phases of the A-VSB proposal, it would have lessened if not
merely prevented the ability to tune into legacy broadcasts.

This is NOT my understanding. I have been told that several of the techniques that are being evaluated for the M/H standard can also be used to help guide the equalizer in the tuner, even if the goal is to capture an 8-VSB portion of the modulated signal. Time will tell.

From what I see today -- and not knowing about the layers of approval before
this stuff becomes public -- ATSC M/H is a "whole new ballgame."

Hmmmm... I believe I said much the same thing, and was reprimanded by Mr. Aitkin:

"Where did you get the notion that almost everything had to change?"

I would also note that just about any improvement in digital modulation or
coding (DVB-H, DVB-T2) doesn't work with well, if at all, with legacy
receivers.  So, that ain't an ATSC issue per se.

The nature of extensibility is to add to existing functionality without breaking it. This allows us to continuously upgrade consumer devices to do new things, but not break existing devices - you just need to upgrade if you want the new stuff.


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