[opendtv] Re: Let the games begin

  • From: John Willkie <johnwillkie@xxxxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Thu, 16 Nov 2006 11:56:13 -0800 (GMT-08:00)

Yes, they will "adhere" to MPEG-2 in the robust channel.  But then, I know what 
that term means, and you don't

Even if they use an MPEG-4 codec, they will still conform to MPEG-2 in the 
program service.

John Willkie

-----Original Message-----
>From: Bob Miller <robmxa@xxxxxxxxx>
>Sent: Nov 10, 2006 9:33 PM
>To: opendtv@xxxxxxxxxxxxx
>Subject: [opendtv] Re: Let the games begin
>Listen, lets get real. If any broadcaster was to seriously consider
>using A-VSB what would they do with it?
>Lets say they use it to simulcast their regular programming in a
>robust mode so it is receivable for almost everyone. Are they going to
>adhere to MPEG2 in this 1.5 Mbps robust channel?
>I doubt it. I think we break company with compatibility right there.
>Yes A-VSB is backward compatible in theory but not in practice. We can
>have our cake and eat it now. We can preach compatibility while going
>If I were a broadcaster and resigned to live with 8-VSB and A-VSB I
>would go full A-VSB with one SD MPEG2 program using minimal bits and
>use the rest with MPEG4 all at 1/2.
>How does that come out? Up to one Mbps up front cost. 18.39/2 = 9.20
>Mbps or more of which you need 3 Mbps for the required SD MPEG2 and
>you have 6.20 Mbps or more left for a robust MPEG4.
>You can do a robust 720P with that right? Good for the speed limit
>maybe. Maybe you could really crimp that MPEG2 by going with a B&W
>weather and traffic map updated once an hour. Then you might get 8
>Mbps or more for the MPEG4 side.
>Of course this would not be in the spirit of staying the course with
>legacy receivers. How long after the death of OTA do these legacy
>receivers still control the discussion? It would seem that we should
>be doing our utmost to stop the injection of more of these legacy
>receivers into the OTA bloodstream instead of offering a subsidy for
>doing so.
>Bob Miller
>On 11/10/06, Bob Miller <robmxa@xxxxxxxxx> wrote:
>> On 11/10/06, Manfredi, Albert E <albert.e.manfredi@xxxxxxxxxx> wrote:
>> > John Shutt wrote:
>> >
>> > > Bob had 5th gen LG boxes, using the same LG block that is in the
>> > > DirecTV boxes. Bob's problem was that those "5th generation"
>> > > chips didn't work nearly as well as the prototype "Cold Fusion"
>> > > 5th generation box that got both Mark Schubin and Sinclair so
>> > > darned excited two years ago.
>> >
>> > I know he tried some no-name clones with the 5th gen LG chip, and that
>> > those clones didn't do "as well as" the prototype. But that doesn't mean
>> > they are crap, either. We have all surmised the reason to be that they
>> > weren't using the better tuner designs.
>> >
>> > AND
>> >
>> > The 5th gen LG-based USB receivers for PCs have been reviewed by the
>> > trade press on several occasions, and they all do very well. I keep
>> > repeating, over and over, that reception of TV stations from 80 Km using
>> > only a (single) indoor antenna, reliably, from these LG 5th gen-based
>> > designs is nothing to sneeze at.
>> >
>> > AND
>> >
>> > The 5th gen LG do not measure as well as the Samsung Gemini in certain
>> > very key areas.
>> >
>> > AND
>> >
>> > The training techniques used in 5th gen sets can also be improved upon,
>> > at least as far as I know, even without changing anything in the bit
>> > stream.
>> >
>> > Put all of this together and it is ridiculous to think that the only way
>> > to get acceptable DTT here is to use only A-VSB. That's just the sort of
>> > annoying rhetoric certain politicians seem to crave. I try to ignore it
>> > and not respond to it. I try.
>> >
>> > A-VSB is instead comparable to either HM or to 16-QAM modes in COFDM.
>> >
>> > For example, tuning the spectral efficiency down gradually to increase
>> > robustness, using the SRS mode of A-VSB, is very similar to increasing
>> > FEC in COFDM, and even backing down to 16-QAM. Same gradual improvement
>> > in robustness.
>> >
>> > Yes, A-VSB can be used. No, it is not mandatory. And if you are after
>> > spectral efficiency, you want to minimize use of A-VSB.
>> >
>> > Bert
>> >
>> > Minimal use of both 8-VSB and A-VSB is recommended and most likely.
>> Bob Miller
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