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In comp.sys.next.programmer, mike@media-lab.mit.edu (Michael Hawley) writes:
>Anyone have the driver code to read digital data
>from audio CD's using the CD-ROM drive?
>Digitizing through the DSP is adequate but silly.

I don't think it's possible with the NeXT CD-ROM drive (or with
most CD-ROM drives for that matter.)

The problem is that CDs have a strange blocking.  If I remember the
numbers correctly, CDs use 24 byte frames. 98 frames form one subcode
block - which contains 2352 bytes of music data and 98 bytes of subcode
data.  75 of these blocks makes up exactly 1 second of stereo 44.1K
music.  CD-ROMs store only 2048 data bytes in each of these 2352 music
blocks.  As I understand it, the standard chips that are used in CD-ROM
drives to read data don't give you access to the extra bytes in each
block, so at best, you would on be getting 87% of the music data.

I've read that the CD-ROM drive on some SGI systems can read all
the music data, so at least someone has made a CD-ROM drive that
can read the music data, but I think it requires more than just
the right software driver.  I could be wrong however.. the NeXT
CD-ROM might be able to do it.

On a related subject, I heard that some of the "newer" NeXT CD-ROM
drives could read multi-session Kodak Photo-CDs.  Does anyone know
if this is true?

Curt

In article <30056@oasys.dt.navy.mil> curt@oasys.dt.navy.mil (Curt Welch) writes:
>I've read that the CD-ROM drive on some SGI systems can read all
>the music data, so at least someone has made a CD-ROM drive that
>can read the music data, but I think it requires more than just
>the right software driver.

The SGI and new Apple CD-ROM drives (Toshiba makes the SGI unit,
while Sony makes the Apple unit) supports the proper SCSI command
to access audio data from audio CDs.  I haven't tried it, but
someone mentioned in a comp.sys.mac.* newsgroup said that with
the newer Macs and the Apple 300i drive, he was able to
disconnect the supplied microphone and record directly from an
audio CD into a Mac SND file.  However it's done, it's certainly
possible--I didn't followup to find out what the sampling rate
was.


Ken
-- 
Kenneth K.F. Lui, klui@corp.hp.com                  3000 Hanover Street MS20BJ
Corporate Administrative Information Systems        Palo Alto, CA  94304   USA
Core Application Technologies                1(415)857-3230 Fax 1(415)852-8026

mike@media-lab.mit.edu (Michael Hawley) writes:
>Anyone have the driver code to read digital data
>from audio CD's using the CD-ROM drive?
>Digitizing through the DSP is adequate but silly.

This is, of course, highly desirable.
It's also illegal.
It's also possible, but requires a ROM change.
Anybody up for dissassembling and rewriting a ROM?
The next problem is how to distribute such a ROM,
since the music industry has persuaded the Feds that such a capability
is in the same category with bomb technology. <}:-)

Steve abell@netcom.com

In article <1993Jan22.195631.21751@netcom.com> abell@netcom.com (Steven T. Abell) writes:
>mike@media-lab.mit.edu (Michael Hawley) writes:
>>Anyone have the driver code to read digital data
>>from audio CD's using the CD-ROM drive?
>>Digitizing through the DSP is adequate but silly.
>
>This is, of course, highly desirable.
>It's also illegal.

Please explain why you believe that this is illegal?  It seems to me
that capturing the digital samples over the SCSI bus is not much
different in the legal sense than getting them over the serial optical
interface available on many CD players.  It seems to me that the "fair
use" provisions of copyright law would permit this for personal use.

As others have mentioned, you can buy CDROM and DAT drives from SGI
that allow you access to the sound samples.  If you ask the vendors of
the drives why they don't make it available, they'll tell you that
they don't believe there's a market for it.

louie

louie@sayshell.umd.edu (Louis A. Mamakos) writes:
>abell@netcom.com (Steven T. Abell) writes:
>>mike@media-lab.mit.edu (Michael Hawley) writes:
>>>Anyone have the driver code to read digital data
>>>from audio CD's using the CD-ROM drive?
>>>Digitizing through the DSP is adequate but silly.
>
>>This is, of course, highly desirable.
>>It's also illegal.

>Please explain why you believe that this is illegal?  It seems to me
>that capturing the digital samples over the SCSI bus is not much
>different in the legal sense than getting them over the serial optical
>interface available on many CD players.  It seems to me that the "fair
>use" provisions of copyright law would permit this for personal use.

>As others have mentioned, you can buy CDROM and DAT drives from SGI
>that allow you access to the sound samples.  If you ask the vendors of
>the drives why they don't make it available, they'll tell you that
>they don't believe there's a market for it.

I believe it is illegal because (so I was told) there is a law against it.
Maybe I'm misinformed, but I don't think so. Remember the big noise when
DAT was first coming out? The music industry was afraid that people were
going to make flawless copies of their wares, and various encoding schemes
were proposed to the gummint boys to make this difficult or impossible.

Yes, there are devices that output digital data, but I believe it is the
case that no *legal* consumer-grade devices are available that will
record those streams. You may ask whether this really makes any sense.
The answer is, of course, "No."

Yes, you can buy peripherals for an SGI that will do this, but that may
be because SGI has persuaded some bureaucrat that it is "professional
equipment", which lives by a different set of rules.

If I'm just flatulating here, somebody please straighten me out.

Steve abell@netcom.com

In article <1993Jan22.195631.21751@netcom.com> abell@netcom.com (Steven T. Abell) writes:
>mike@media-lab.mit.edu (Michael Hawley) writes:
>This is, of course, highly desirable.
>It's also illegal.

Why is it illegal?  Among other things:

1.  If I press an audio CD, I can do anything I damn well please with
    the data on it.

2.  If I own a CD, I have the right to have "archival" copies (ie tapes,
    other digital representations, etc.) as long as I don't distribute
    them to others.

Aside from the technical problems, there's no underlying legal problem
with it unless the user chooses to abuse it.




-- 
Sean T. Lamont                           |   "Don't oppress me, It's
zeno@genetics.washington.edu             |    'computer of color!' "
lamont@abstractsoft.com                  |_______________________________
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