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.wav to CD or DVD a good idea for archiving?

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Anonymous
June 2, 2005 2:23:05 AM

Archived from groups: rec.audio.pro (More info?)

As the subject says...I saw a post here a couple of years ago from someone
playing with Ampex tape but got written off for saving to a lossy
compression format. I'm thinking of doing the same but with .wav files to
either CD or DVD discs...good idea?


John
Anonymous
June 2, 2005 2:23:06 AM

Archived from groups: rec.audio.pro (More info?)

Hi John,
If you back up.wavs to either cd or dvd as a data disc, you are
bascially just transfering the same information thats on your drive to
a removeable format. The .wav is still a wav whether its on a harddrive
or a data disc.
As long as you save it as data in Toast or whatever, the file will
remain the same.
Cheers,
D.Slevin
Anonymous
June 2, 2005 2:23:06 AM

Archived from groups: rec.audio.pro (More info?)

Hi John,
If you back up.wavs to either cd or dvd as a data disc, you are
bascially just transfering the same information thats on your drive to
a removeable format. The .wav is still a wav whether its on a harddrive
or a data disc.
As long as you save it as data in Toast or whatever, the file will
remain the same.
Cheers,
D.Slevin
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Anonymous
June 2, 2005 2:23:06 AM

Archived from groups: rec.audio.pro (More info?)

hi John,

yeah as studiorat says... identical copies is what you want.

the only thing is, make sure u 'copy' the original wavs and don't
'save-as' or something just for safety! depending on the software
being used, u may end up with a different quality wav (24bit ->
16bit)...

and use good CDR's i've read stories of the disc's fading away - so for
master copies best spend a bit more £

cheers,

Luke
Anonymous
June 2, 2005 2:23:06 AM

Archived from groups: rec.audio.pro (More info?)

Well there are lossless compression formats but in general this is fine.
Some people don't feel that CD/DVD media is a good option for long-term
archiving (20 years+) because the oxygen trapped between the substrate
layers will eventually oxidize and destroy the data. I personally do not
know if this is true or not. But burned media for sure has a certain
lifespan due to the dyes used in the disks as the storage medium.

I heard once that the Library of Congress was still archiving music using
records instead of digital or optical media formats, for these reasons.
Although susceptible to heat or breakage, they will pretty much last forever
outside of that. Again, who knows if this is true.

So maybe the answer is to archive all of your material onto records. Haha.

-Ben

"John T" <hotflashesnil@hotmail.com> wrote in message
news:429da8a9$0$26242$afc38c87@news.optusnet.com.au...
> As the subject says...I saw a post here a couple of years ago from someone
> playing with Ampex tape but got written off for saving to a lossy
> compression format. I'm thinking of doing the same but with .wav files to
> either CD or DVD discs...good idea?
>
>
> John
>
>
Anonymous
June 2, 2005 4:07:26 PM

Archived from groups: rec.audio.pro (More info?)

Thanks Luke and studiorat, much appreciated!


John
Anonymous
June 4, 2005 5:50:39 AM

Archived from groups: rec.audio.pro (More info?)

A few thoughts on archiving:

0) Try to start with media you have at least _reasonable_ trust in. No
bargain-bin no-name media; it _MAY_ be fine, but if you're going to the
trouble of archiving stuff that's not a great bet to take. "When you
want a bargain in the worst possible way, that's generally the way you
get it."

1) Use a recording format with error recovery codes (data CD), not one
which attempts to interpolate past errors (audio CD). Or, if you're
feeling paranoid, burn both. Data CD is more likely to be perfectly
playable after being slightly damaged, audio is more likely to be at
least _partly_ playable after being severely damaged. (I've got an audio
CD which was pretty badly beaten up and run over; I was able to pull 8
of the 12 tracks off it in reasonably listable condition without trying
very hard. Let's hear it for interpolation...)

2) Remember, digital-to-digital copying is lossless. So any time you're
nervous about how much life is left in your media, just recopy to fresh
media, thereby resetting the clock. Yeah, it's a hassle unless you've
either got a relatively small pile of archives or some form of automated
media handling system, but fighting entropy takes energy...

3) If you're archiving for the long term, store compatable hardware and
software with the media. Think how you'd feel if you had the archived
master but no device that could read it and no software which still
understood that file format... or if that software only ran on a
processor which is no longer available. (See also point 2; periodic
recopying is an opportunity to move the data to new media and new formats.)

4) Consider where and how you're storing the physical media. If you're
serious about this, consider burning multiple copies and storing the
extras off-site so if the building burns down you're left with more than
a puddle of plastic, and/or investing in a "media chest" which is
designed to protect these materials from a fire (a normal
good-enough-for-papers box is inadequate for computer or photographic
media).
Anonymous
June 4, 2005 12:55:51 PM

Archived from groups: rec.audio.pro (More info?)

Joe Kesselman wrote:
>
> 2) Remember, digital-to-digital copying is lossless. So any time you're
> nervous about how much life is left in your media, just recopy to fresh
> media, thereby resetting the clock. Yeah, it's a hassle unless you've
> either got a relatively small pile of archives or some form of automated
> media handling system, but fighting entropy takes energy...

WAV files have no inherent error correction. Compute and store
checksums for them, preferably on separate media. Run a scripted
process regularly to verify the archive integrity. This gets difficult
or impossible with large numbers of optical disks.
June 4, 2005 7:10:01 PM

Archived from groups: rec.audio.pro (More info?)

If you are archiving then there is a difference between CD and DVD
lifetimes. I believe the latter are intended for 100 years whereas many
have had less than happy experiences with old CDs. At high resolution
you do not get much on a CD. I would suggest DVD is the better option.
Anonymous
June 4, 2005 9:34:05 PM

Archived from groups: rec.audio.pro (More info?)

Kurt Albershardt <kurt@nv.net> wrote:
>Joe Kesselman wrote:
>>
>> 2) Remember, digital-to-digital copying is lossless. So any time you're
>> nervous about how much life is left in your media, just recopy to fresh
>> media, thereby resetting the clock. Yeah, it's a hassle unless you've
>> either got a relatively small pile of archives or some form of automated
>> media handling system, but fighting entropy takes energy...
>
>WAV files have no inherent error correction. Compute and store
>checksums for them, preferably on separate media. Run a scripted
>process regularly to verify the archive integrity. This gets difficult
>or impossible with large numbers of optical disks.

That's what the filesystem is for!
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
June 5, 2005 3:33:50 AM

Archived from groups: rec.audio.pro (More info?)

andy wrote:
> If you are archiving then there is a difference between CD and DVD
> lifetimes.

I suspect there's less difference between those than between
brands/qualities of CD media, but I haven't checked the literature
recently. (They shouldn't be _that_ different if a single drive can
happily burn both...?)

DVDs are certainly more convenient since they're higher density. On the
other hand, increased density does mean increases vulnerability to a
Small Random Event unless the ECC has also been beefed up...
Anonymous
June 5, 2005 3:35:39 AM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:
> That's what the filesystem is for!

Yep. What gets onto disk is not necessarily just the bits you provided.
I _think_ data CD filesystems do carry some error correction coding, but
I'd have to dig out the spec or consult my nonresident expert to be sure.
Anonymous
June 5, 2005 12:35:01 PM

Archived from groups: rec.audio.pro (More info?)

Joe Kesselman <keshlam-nospam@comcast.net> wrote:
>Scott Dorsey wrote:
>> That's what the filesystem is for!
>
>Yep. What gets onto disk is not necessarily just the bits you provided.
>I _think_ data CD filesystems do carry some error correction coding, but
>I'd have to dig out the spec or consult my nonresident expert to be sure.

They do a huge amount of it. The error rate on the CD is high enough
that it just plain wouldn't work if they didn't.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
June 5, 2005 12:50:21 PM

Archived from groups: rec.audio.pro (More info?)

In article <F8SdnTwDfLKX7j_fRVn-hQ@comcast.com>, Joe Kesselman wrote:
>Scott Dorsey wrote:
>> That's what the filesystem is for!
>
>Yep. What gets onto disk is not necessarily just the bits you provided.
>I _think_ data CD filesystems do carry some error correction coding, but
>I'd have to dig out the spec or consult my nonresident expert to be sure.

CD-ROM has an extra ECC layer beyond audio CD at the hardware level. At
the filesystem level there is no additional ECC or EDC.

-- Adam
Anonymous
June 5, 2005 2:00:51 PM

Archived from groups: rec.audio.pro (More info?)

Joe Kesselman wrote:
>
> Yep. What gets onto disk is not necessarily just the bits you provided.
> I _think_ data CD filesystems do carry some error correction coding, but
> I'd have to dig out the spec or consult my nonresident expert to be sure.

Not the filesystem exactly, but when a CD is written in data format (as
opposed to audio), a different (or additional) low level error
correction mechanism is used, which can fully correct higher error rates
by using more redundancy. That's why the raw capacity of a CD with a
file system on it is 650Mb, while for audio it is 750Mb.

--
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