Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!ncar!gatech!prism!gt8021a
From: gt8021a@prism.gatech.EDU (EASON)
Newsgroups: sci.electronics
Subject: Re: Digital Audio Tape stuff
Message-ID: <31848@hydra.gatech.EDU>
Date: 26 Jun 91 21:09:51 GMT
References: <4870@inews.intel.com>
Organization: Georgia Institute of Technology
Lines: 29

In article <4870@inews.intel.com> dpuchals@demos.intel.com (Douglas R. Puchalski) writes:
>I have a few questions relating to digital audio and standard
>audio casettes.
>1) Does anybody know how to read raw audio data from a CD in a
>   CD-ROM player on a rs6000 or a dec3100 so that the audio
>   waveform(s) can be analyzed?

I've been working with Hitachi CD-ROM drives for close to a year now, 
writing a driver and higher software.  Every ROM or audio block on a CD 
has, associated with the data, a subcode which tells the type of data
in the block, and whether or not a digital copy of the data is allowed.
Every audio CD I have looked at has the "no copy bit" set to 0 (no copy
allowed), and the drive returns an error status when a request is made
to read those blocks.  You can give the drive an audio play command
(built-in D/A converter & headphone jack), and everything plays fine,
but you can't get a digital copy of the audio.

This may be a Hitachi-specific hardware copy protection implementation, 
but it would not surprise me at all if (most/all) other CD-ROM manufacturers
had this, too.  Rather disappointing to a DSP student!

Anyone know the RS-6000 in particular?  Who makes their drives?  BTW, we have
one in our lab here, so I could check later if no one else knows.

-- 
Bill Eason - EE (DSP) grad student
Georgia Institute of Technology, Atlanta Georgia, 30332
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