[Gllug] When a CD is not a CD

[Liam Smit]

> While looking in Borders, I came across a set of CDs that had a Copy
> Controlled logo. Being curious, I bought one of each.
> Playing on an old CD player seems OK.
> 
> cdparanoia -Z n
> will capture the data of track n to a .wav file.
> However, this file then has the corruption signal audible.
> It is a crack of noise that seems to be in different places at different times
> depending on the track. Sounds like a needle on a record player is jumping
> for dust.
> 
> Has anyone else come across this?

I've read of it. They intentionally insert errors into the tracks to
prevent playing the CD back on a computer.

> Why can I not hear this on the old CD player?

Error correction / noise suppression of the CD player kicks in renders
it inaudible, I believe this is analogue process..

> Apart from connecting a lead from the CD player headphones to a Line In and
> watching the sound level is not too high, is there an easier way to listen to
> this under Linux?

Put the CD in your CD player and record the cleaned analogue signal
off of it as a WAV and then burn to CD. Will be a slight degradation
in quality, whether you can discern it is another matter entirely.
 
cheers
Liam
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