Interesting People mailing list archives

IP: Re: Copy-protected CDs quietly slip into stores


From: David Farber <dave () farber net>
Date: Wed, 18 Jul 2001 19:44:51 -0400



To: farber () cis upenn edu
cc: lauren () vortex com
Subject: Re: IP: Copy-protected CDs quietly slip into stores
Date: Wed, 18 Jul 2001 16:36:22 -0700
From: Lauren Weinstein <lauren () vortex com>

There are two particularly interesting technical aspects to
this issue:

  1) The copy-protection mechanism involved (as I understand it from
     published reports) attempts to avoid introducing any distortion for
     "ordinary" CD players, while introducing various forms of audible read
     errors when those audio CDs are played on CD-ROM drives.  This not only
     affects typical CD-ROM drives in standard computers and laptops, etc.,
     but also apparently some high-end consumer audio players that use CD-ROM
     technology in their units.

  2) The copy-protection effort seems to be largely predicated on the
     premise that if people can't make a first-generation digital copy, they
     won't copy at all and won't try to swap the material.  But of course,
     CDs can also be copied to MP3 files (or whatever) through an analog
     connection to a computer (albeit with more hassle in the absence of
     specialized software) with excellent audio quality.  All that the
     copy-protection system does is try to prevent a first-generation
     digital copy straight off the CD.  However, if instead an initial
     analog-generation copy is made, further digital copies could be made
     from that initial file without any audio interference as far as I
     know.  Would most users of file-swapping services (for example) notice
     any audio difference between these two modalities of copies?
     I suspect not.

So it would appear that the overall effective scope of the copy-protection
system may actually be fairly limited in terms of reducing piracy, while
still potentially creating hassles for significant numbers of legitimate
users who try to play their audio CDs on CD-ROM-based systems.

--Lauren--
Lauren Weinstein
lauren () pfir org or lauren () vortex com or lauren () privacyforum org
Co-Founder, PFIR: People For Internet Responsibility - http://www.pfir.org
Moderator, PRIVACY Forum - http://www.vortex.com
Member, ACM Committee on Computers and Public Policy







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