[Paranoia] Audio data varies from drive to drive?

[Laurent Charrière]

Paolo Saggese wrote:
> are you sure that the differences you see are not just in the "silence" 
> at the beginning (and/or at the end) of the track and/or a "byte‐shift" 
> between the files?
> 
> try comparing the wav files using "shncmp -s": 

I'm ashamed to report that indeed the difference in audio data was only 
caused by differences in silence at the beginning and at the end of the 
track. I.e., the tracks have the same number of bytes but there is a 
variable number of 0x00 bytes at the beginning depending on the drive. 
This is compensated by a variable number of 0x00 bytes at the end of the 
track.

snhcmp reports this as "extra samples" which is a little misleading 
since the number of samples is the same for each track (the WAV header 
is identical, and the byte length is the same). In any event the number 
of "extra samples" seems to always be the same for a same drive, on 3 
discs I tried.

I apologize for the false alarm.

Is there a way to know the exact offset added by each drive, and 
compensate for it while ripping? Comparing files only yields a relative 
offset between each drive. I tried running cdparanoia --analyze-drive 
but didn't see a clear indication of what the offset measured is, or if 
indeed it was measured at all.