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Re: Official Message From Comcast-- a question)
From: David Farber <dave () farber net>
Date: Mon, 15 Sep 2008 19:30:43 -0400

Begin forwarded message:

From: Lauren Weinstein <lauren () vortex com>
Date: September 15, 2008 6:42:25 PM EDT
To: dave () farber net
Cc: lauren () vortex com
Subject: SDV (was: Re: [IP] Re: Official Message From Comcast-- a question)

From: Dan Ritter <dsr () tao merseine nu>
All this screams out for Switched Digital Video (over IP or over
QAM), in which the provider makes multicast streams available
for viewing. If no one in a cable neighborhood is watching one
of the 400 channels that no one watches, no bandwidth is


Switched Digital Video (SDV) has its own interesting attributes,
some of which are also potentially anti-competitive.  First, I'll
note that IPTV systems (like AT&T U-verse) are fundamentally
designed to take advantage of distributed architectures.  U-verse
has its own major problems though -- like the fact that even after
the recent upgrades it's limited to no more than two HD streams to a
household (plus a number of SD streams) on a single copper pair.

While there may be ways to boost this again without compromising
video quality too much, AT&T seems to have underestimated the speed
with which HD transmissions would themselves become the "normal"
fare for most viewers (and indeed, the Comcast/TW bandwidth caps
seem to be similarly using standard definition programming as their
benchmarks, rather than more realistic HD numbers).

But SDV itself has been embroiled in a battle between CableLabs and
third-party companies like TiVo who depend on CableCARDs for access
to cable company programming.  External "tuning adapters" to deal
with SDV have just now started becoming available since I wrote (a
bit over a year ago):

Important Warning Regarding New HD TiVo and Cable System Incompatibilities

and shortly thereafter:

The Coax Straightjacket: Stopping Cable Copy-Protection Abuse

Ihe issues of third-party access to VOD/PPV, etc. programming vs.
cable industry demands that only *their* software be allowed to
access these facilities are still very much in play (the "keyword"
in these disputes is "OCAP" - OpenCable Applications Platform).

Just ask me if you want more info on these areas.  Thanks.

Lauren Weinstein
lauren () vortex com or lauren () pfir org
Tel: +1 (818) 225-2800
Co-Founder, PFIR
  - People For Internet Responsibility - http://www.pfir.org
Co-Founder, NNSquad
  - Network Neutrality Squad - http://www.nnsquad.org
Founder, PRIVACY Forum - http://www.vortex.com
Member, ACM Committee on Computers and Public Policy
Lauren's Blog: http://lauren.vortex.com

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