Klarinet Archive - Posting 000642.txt from 2000/12

From: "Benjamin Maas" <benmaas@-----.com>
Subj: RE: [kl] CD-RW for music vs. data?
Date: Tue, 12 Dec 2000 19:32:57 -0500

> OK,
> Do the CD-RW drives write the special tax/copy-protect code
> on the CD-RW
> discs? Or could they? And then play those discs on any CD
> player? Or at least
> the ones that can physically read it. Didn't Compaq (?) get
> nailed on that issue
> in Germany in the last few weeks?
> Edward

Perhaps somebody can come up with a crack for it, but it is actually easier
to find the circuit in the burner and disable the copy protection. Many
burners also have an unpublished backdoor that disables the copy protection.

> I'm not sure how the copy-protect codes work. The Hhb I use can
> add a copy
> protect code to prevent digital duplication to another CD deck (I think
> that is what is does - Benjamin??), but that doesn't prevent
> duplication to
> a DAT and then back to a CD without the code - and use the CD for
> mastering
> other CDs.
>
> I'm not sure of the law in this regard - my question is more -
> how does the
> code work and what are its limitations?
>
> Sincerely,
> Roger Garrett

That copy code that the HHB can add is what the consumer CD decks would be
sensitive too... Also, consumer DAT machines (ie. Sony TCD-D7/8, etc..) are
sensitive to this.

The copy protection code (that is very easily broken) is called the Serial
Copy Management System (SCMS). It works by adding a flag bit into the
stream of music. Players can detect it, but you cannot hear it. You can
set that bit to represent any number of copies allowed, 1 copy allowed, or 0
copies allowed. If you make a copy of a 1 copy allowed disc, your new disc
will have the flag for 0 copies allowed.

Interestingly enough, SCMS is feeble enough that it can be stripped by
special boxes, most pro gear ignores it, and doesn't even transmit over an
AES/EBU digital line (or if it does, it is just ignored by the receiving end
as AES/EBU is a balanced digital connection).

Now for consumer recorders (ie. you walk into your local Circuit City to buy
a cd recorder), SCMS is quite definitely noticed. As I said in an earlier
post, to please the RIAA, the require a special tax on all CDs recorded by
these consumer recorders. The assumption was that they would be used for
the small-scale piracy of CDs (home use). Therefore, they wanted to get a
piece of the action and to make sure the artists would get something as
well. Thus the need for special "music" CDs. The tax has been paid on
these and it is coded into the disc in the same way that the manufacturing
info is coded in (on the extreme inner part).

Hope this helps clarify things a bit.

--Ben

Benjamin Maas
Freelance Clarinetist and Recording Engineer
Los Angeles, CA
benmaas@-----.com
http://www.fifthcircle.com

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