[opendtv] Re: "we'll forever be stuck with by going ATSC"

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "OpenDTV (E-mail)" <opendtv@xxxxxxxxxxxxx>
  • Date: Mon, 10 Jan 2005 10:29:55 -0500

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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