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From: grahaf@otago.ac.nz
Newsgroups: sci.electronics
Subject: Re: Digital Audio Tape stuff
Message-ID: <1991Jun27.163835.626@otago.ac.nz>
Date: 27 Jun 91 05:47:09 GMT
References: <4870@inews.intel.com> <31848@hydra.gatech.EDU>
Organization: University of Otago, Dunedin, New Zealand
Lines: 31

In article <31848@hydra.gatech.EDU>, gt8021a@prism.gatech.EDU (EASON) writes:
> 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.
> 

Very curious. I have seen a number of high end audio CD players with Digital
Out connectors on the back. I have seen them playing CDs through an amp which
has the appropriate hardware without any audio leads. The sugestion is that the
Digital Out is raw data and the amp does the A/D conversion. I have no idea if
this is what actually happens but there is only one cable to the amp from the
player. The connectors are just phono plugs and the cable is standard audio. It
may be possible to get the data this way. Not as fast or convienient as a
CD-ROM but....

Good luck,

Graham.