[opendtv] Re: New Thread: What becomes of Legacy Analog Equipment
- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 30 Nov 2007 19:37:49 -0800
You are missing much.
I don't see how you can use a different form of modulation within a single 6
Mhz channel and be backwards-compatible. Indeed, your friend Richard Bogner
was told in a face-to-face meeting with the FCC this week that he cannot use
FM modulation in the same channel as 8-VSB because no interference studies
have been made. (Richard told me this in a series of private email
messages, which I summarized in a message this week on my PSIP list.)
Also, I don't see how you could save bits by transmitting black and white
images, since chroma and luma are needed to make pictures, even if the
source is black and white.
The chroma formats permitted by MPEG-2 are 4:2:0, 4:2:2 and 4:4:4. They are
component: A matrix, block or single sample from one of the three matrices
(luminance and two chrominance) that make up a picture.
I note that one of the m/p/h proposals is from Qualcomm, which has spent
mightily - perhaps a billion dollars - on the MediaFlo demo infrastructure
in the U.S. It would be the height of "creative destruction" if their
proposal to the ATSC resulted in destroying that infrastructure or wasn't
compatible with it, nor wasn't backwards compatible with 8-VSB. I think
that trying to integrate a single-carrier system and a multiple-carrier
system into the same 6-Mhz channel is "mightily difficult" if not simply
impossible.
Perhaps you haven't thought much about it. I also note the news today that
Google has decided to bid in the next auction round. Perhaps that is behind
your newly-resurected interest in bashing 8-VSB and the parties that have to
make a business around it?
Hope this helps
John Willkie
_____
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Bob Miller
Enviado el: Friday, November 30, 2007 6:50 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: New Thread: What becomes of Legacy Analog Equipment
Sort of lets change the modulation and say we didn't by letting a completely
different modulation use all but a small part of the 6 MHz? Or am I missing
something?
Maybe it wasn't a joke when I was talking about doing an SD weather type
information channel in black and white to minimize bits used for SD and use
the rest with what, DTMB or some clone with a different name to disguise it
and MPEG3?
Bob Miller
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