[opendtv] Re: Democrats Air Concerns About Analog Switchover
- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 20 Nov 2006 14:30:06 -0800
Gee, everybody else is telling me that MHEG was dead on arrival, and is
dying more and more every day. I think you might benefit from actually
seeing the dearth of MHEG applications in Europe today.
I seriously doubt that OCAP/ACAP/GEM was being developed while you were
working on ATSC projects. Even if they were, the fact that they now have a
common subclass where each operates definitely did not exist then: it was
only announced for the first time two years ago at the Tech Retreat.
And, "being developed" is a lot different than "working" well. Together.
There is at least one multi-vendor A/90 ACAP/OCAP/GEM field trial going on
today, but I've probably already said too much. When I talk to other
vendors, they ask "will this be something that really happens, or will it be
like MHEG?"
You and Mark are clearly incorrect about AC-3 receivers being not fully
compliant with the A/52 spec. Everything about permitting multiple audio
streams to be rendered in receivers was made optional. While 0 receivers
provide this service, every receiver that does not is fully compliant with
the spec; they just don't live up to the potential of what AC-3 can offer.
At least we now have products that handle the dialnorm issue.
If you think that captions work was "completed" years ago, you are likely to
be surprised in coming months. Due to non-disclosure requirements of one or
more groups in which I participate, I can comment no further.
I can say that the CEA-608-C spec is a horrible hodge-podge borne of the
necessity to maintain compatibility with legacy units.
The real world caption situation is troubled, to say the least, due to
screwy combinations of "optional" requirements in A/65 that are
countermanded by mandatory requirements in CEA-608 and 708, and the very
mandatory requirements of the FCC, which has the power to impose fines and
"gets" $20K or more for missing captions in certain situations.
Wanna have fun? Try to switch caption streams in real-time with
frame-accurate results, while maintaining compliance with MPEG-2, A/65,
A/53, CEA-608 and -708. Can you be blamed for the mess? :-)
John Willkie
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On
Behalf Of Craig Birkmaier
Sent: Sunday, November 19, 2006 4:09 AM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Democrats Air Concerns About Analog Switchover
At 11:42 AM -0800 11/18/06, John Willkie wrote:
>And, you have much work to get up to speed with what's going on now.
>
>ACAP/OCAP/GEM?
These were all being developed at the time I was working on the
standard. For what it is worth, only rather lame program guides have
actually been deployed in the U.S., while Europe is enjoying a wide
range of interactive services, mostly built around MHEG.
>Software Download Service?
>Data broadcast in general
I originated the data broadcast work in general, and in the ATSC
specifically. I spent about two years trying to help them re-invent
the wheel before giving up. I have several papers I presented at
SMPTE conference on this subject that I can share with you; these
papers lay out the general requirements and the services that can be
supported. The ATSC began work on A-90 in 1997. Unfortunately, the
work was dominated by companies intent on building the U.S. standard
around the DS-MCC data carousel work that had been completed in
Europe. We spun or wheels for several years before Rich Chernock was
able to get things focused on what became A-90. The standard is all
but unused today. The only work that is pertinent is relatd to the
ability to encapsulate IP data grams so that one can escape the
standard to do something useful.
>E/A-VSB
Talking about re-inventing the wheel...
>E/AC-3
Not my bag. Most of this was decided early on in the process. As Mark
points out, virtually ALL ATSC receivers are not fully compliant with
the services in the standard.
>VC-1/AVC
I was involved in both SMPTE and MPEG committee work when these
efforts started.
>Captions, etc.
This work was completed while I was working on other aspects of the
ATSC standard including the interlace/progressive task force and
T3/S6, which debated the SDTV formats that were added to the standard
in the summer of 1995.
Regards
Craig
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