[opendtv] Re: "we'll forever be stuck with by going ATSC"
- From: "Tom McMahon" <TLM@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 10 Jan 2005 07:37:14 -0800
You fail to factor which European (and other DVB) countries have started DTV
and which haven't even started yet (thereby giving them
far more options).
The Main ATSC Standard doesn't support any advanced video codecs so your ATSC
options aren't enabled.
Your bitrate figures are in error.
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On
Behalf Of Manfredi, Albert E
Sent: Monday, January 10, 2005 7:30 AM
To: OpenDTV (E-mail)
Subject: [opendtv] Re: "we'll forever be stuck with by going ATSC"
Tom McMahon wrote:
> Another thing that came out at CES 2005 was the fact that the forced,
> non-market-driven, premature US jump to ATSC HD has effectively locked
> in US DTV terrestrial MPEG-2 for the rest of our natural lives.
> ...
> Europe's delay on terrestrial HD means they can adopt more enlightened
> compression technologies for their HD services, thereby enabling a
> great deal of latitude on quality and channel capacity and business
> operations management. They are going to use H.264/AVC.
Sorry, Tom, but this is one of those glass half full glass half empty
situations, and you have ignored the other half.
Europe's decision to delay HD introduction means that they will "forever" be
saddled with having to transmit simultaneous MPEG-2 SD
streams, to keep the SD-only sets from going black. So in both Europe and
Australia, HD will come at the expense of enforced
simulcasts. Since AVC is at most twice as effective as MPEG-2, and in some
cases only 50 percent better, enforced parallel program
streams, one SD MPEG-2, the other HD AVC, won't save much, and might actually
require more bandwidth than having a single HD stream
compatible with all receivers.
Simple arithmetic:
MPEG-2 HD stream compatible with all sets requires 10 to 19 Mb/s, the lower
figure being non-sports.
MPEG-2 SD + AVC HD requires about 5 + 6 Mb/s to
5 + 12 Mb/s, which means about 11 to 17 Mb/s total.
Is there some compelling argument to go to separate streams?
> While the ATSC might someday offer a new standard for mobile (EVSB)
> services using an advanced video codec(s), it is unlikely that can do
> anything for the legacy, mainstream HD part of the ATSC standard in
> this country. The installed base of ATSC HD receivers cannot change,
> and, short of terrestrial simulcasting HD using an advanced video
> codec (which won't make a whit of business sense), there's no way out
> of that MPEG-2 box.
Broadcasters *can* take the European approach in the US, just as easily as they
can in Europe. Use MPEG-2 just for an SD
transmissions, use AVC or VC-1 for HD parallel streams. ATSC can easily
accommodate this. The only question is whether it buys you
anything.
US HD users *can* be forced to buy STBs which support AVC or VC-1, to keep HD
programming on their HD sets.
This would, at worst, p*ss off a lot of HD owners.
And with good reason.
Bert
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