Subject: Re: More than you wanted to know about DAT, MD, DVD, Reverse Eng, etc
From: Brian Behlendorf <>
Date: Tue, 28 Apr 1998 11:32:03 -0700

At 03:10 PM 4/27/98 -0700, John Gilmore wrote:
>I record a lot of concerts, WITH
>the permission of the artists, but have to subvert my equipment to do
>it.  Every time I buy more blank MD's, I think again about how much I
>hate the system, and how I would instantly switch over to a freed
>random-access digital audio recording system if only some manufacturer
>would offer one!

DAT.  The Sony M1 portable DAT recorder is has professional-quality A/D
converters, has their proprietary 7-pin digital in/out which can be
converted to S/PDIF, and has *no*SCMS*.  It's $715 through a place over the
web.  I just ordered one actually.  DAT's are less expensive per minute
than MD's.

>I won't lengthen this message much on DVD, DIVX, and reverse
>engineering.  DVD video discs are encrypted using a "region key";
>there are six regions defined.  If you buy a German DVD, your US
>player won't play it since it doesn't have the European master key.
>This protects the movie companies' distribution systems so they can
>trickle out the product, market by market, without the millions of
>e.g. US discs, where the movie has been released for six months,
>escaping into the European or Asian markets where they're still
>charging "first-run" prices.

Yep, this is bad - though there are DVD players on the international market
(albeit at a markup - base price about $800) that claim to be able to play
DVD's from any of the regions, and also claims to be "future-proofed"
against changes by having programmable ROM's.  I don't know enough about
computer DVD drives to know whether the region decoding can be done in
software; if so, then it's conceivable that computer DVD players could be
made region-free as well.  

>DIVX is even more excessive.  It builds a royalty system on top of DVD.
>Instead of renting videos, you buy a DIVX disc at a video rental store.
>Your DIVX player will only play it for the 48 hours starting when you
>pop the disc in for the first time.  After that, it will charge a
>royalty to your credit card whenever you try to play the disc again.
>If you just wanted to "rent" it for 48 hours, you can throw the disc away.
>The player remembers the royalty payments and demands to be connected
>to a phone line to call an 800-number and dump them periodically; if you
>don't connect it, it refuses to play any discs until you do.
>The whole thing is secured by crypto to protect the intellectual property.

Yes, DIVX is really evil, it was a standard invented by Blockbuster and
their lawyers.  Even if you want to BUY the discs, which you can for the
same price as a regular DVD, you STILL have to connect to the 800-number to
verify your access.  Which means that if the company at the other end of
that 800 number goes south, suddenly your entire "investment" goes, well,
"poof".  Market forces will help not make that a total loss of course (I'm
sure some company will buy the database & access controls), but it's still
a rather terrifying prospect.

>Now the same gang is targeting computers (via the IEEE 1394 FireWire
>digital interface).  For an overview of these and related activities
>(e.g. Divx), see and search the DVD
>FAQ (HTML version) for FireWire and CGMS.

Eek.  Thanks for the references.


pure chewing satisfaction