Re: [ARSCLIST] MP3

[Mike Richter <mrichter@xxxxxxx>]

Steven C. Barr(x) wrote:
> ----- Original Message ----- 
> From: <Mwcpc6@xxxxxxx>
> > It is the error correction feature of digital media that it
> > possible to store audio without degradation over time ... until someone
> forgets to
> > backup and it is completely gone forever.
> As I understand it (and I may not be correct)...so far, we have no data
> on life spans for the various media used to store digital information?
> However, I have a number of CD's that show NO visible evidence of
> physical damage or deterioration...but refuse to play some, most or
> all of their content without random "skipping" of parts...and these
> are pressed, not "burned" discs...

Whatever data may exist on longevity are the property of the respective 
manufacturers. They do not choose to disclose them.

Visible changes may exist without audible impact; most audible losses 
over time show little or no effect to the naked eye.

Note that there is error correction for audio as well as for data. The 
difference is an extra layer of ECC for data which makes the resulting 
disc more tolerant of error. That layer costs about 13% of capacity, 
explaining the difference in space needed for redbook WAVs and their 
equivalent as CD-DA.

There is a page on ECC in the primer at my WWW site:
  http://www.mrichter.com/cdr/primer/bits.htm
Other pages may also be of interest.

Mike
--
mrichter@xxxxxxx
http://www.mrichter.com/