[luau] Duplicating Music CD

MonMotha monmotha at indy.rr.com
Wed Nov 27 20:28:00 PST 2002


W. Wayne Liauh wrote:
> Reading an audio CD is much more complicated than we thought.  (Think 
> about it, even xcdroast is not able to do direct copying of audio CDs.) 
> The problem I am having now appears to be that the xcdroast that came 
> with RH 8.0 is broken.  I installed the "updated" xcdroast rpms which 
> seems to throw everything in further chaos--now everything is broken, 
> including cdrecord.
> 
> I don't think you can access an audio CD without going through cdda2wav 
> or cdparanoia or other equivalent programs.  Insert an audio CD, run any 
> CD player program, then do a kdf, and you will find out that the CDROM 
> is not even mounted.
> 

This is correct.  There is no filesystem on audio CDs to mount nor is 
the data stored in the same way as the CD-ROM standard.  CD Audio takes 
advantage of the fact that the data type is known to pack more data into 
the same space and still have acceptable ECC (which is how many copy 
protection algorithms work, by munging the ECC so intelligent devices 
will choke on it).

cdparanoia or cdda2wav use the reader's "rip" function to have it read 
the CD audio digitally (sometimes at very high speeds, sometimes at 1x, 
sometimes somewhere in between) and get a PCM data stream back.  This is 
different from the normal play CD functionality which has the drive 
itself do a D/A conversion and put an analog signal out the little CD 
audio cable (not the SPDIF one, but the 4 pin analog one).

--MonMotha
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