[opendtv] Re: Frames Per Second of 720P
- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sun, 27 Jul 2008 10:19:15 -0700
I should have also pointed out that there will no doubt be future
improvements on enhancements for home viewing in the ATSC space, but that --
aside from still-lingering reception issues -- it works pretty damn good.
John Willkie
-----Mensaje original-----
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Craig Birkmaier
Enviado el: Sunday, July 27, 2008 7:09 AM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: Frames Per Second of 720P
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?"
Really?
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
>screen.
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All standards are out of date in this time frame at the time they are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
>U.S.
Really?
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
>so.
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.
Regards
Craig
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