Tom Fine wrote:
> I had a go-around on a related topic, about whether CDR's full of MP3's 
> get more damaged from over-time breakdown vs. audio CD's. My suggestion 
> was that since data is packed tighter on an MP3 CD due to the 
> lossy-compression format of the data, a relatively small glitch in the 
> CD would zap more audio content. I was told this is not the case but was 
> unconvinced by the argument -- which was basically that both audio and 
> data CD's have robust error correction and a glitch of the same physical 
> size would be correctable in both cases, or not. I still don't archive 
> anything in a lossy-compressed format.
> -- Tom Fine

1. Data CDs have an extra, robust layer of error correction missing from 
CD-DA. The probability of an error getting through is much lower for a 
(data) disc of compressed audio than for a CD-DA.

2. A single error on a CD-DA is highly localized and unlikely to be 
audible. A single error on a data file will have wider impact and may be 
audible or may make the file unplayable.

3. CD-DA players implement error concealment to suppress the audible 
effect of transient errors.

If your objective is a recording that sounds good despite errors, you 
may be better off with CD-DA. If your objective is exact reproduction of 
the source, a data disc is the better choice using either no compression 
or lossless compression.

May I again suggest that measuring error rate on a substantial batch of 
discs is a good way to determine how good they are and how likely they 
are to remain good over time. Repeating that measurement during storage 
is the best way to detect degradation before failure. While the level of 
testing offered by Media Sciences is ideal, in practical terms just 
tracking C1 and C2 error rates will suffice for most purposes.

[log in to unmask]