
Optical Disc Data Rot: Burned CDs going bad - walterbell
https://www.howtogeek.com/682807/the-cds-you-burned-are-going-bad-heres-what-you-need-to-do/
======
euix
Man I used to burn so many cds back in the day. I remember when I was kid and
the first cd-recorders came out, they cost something like 2000 dollars and
burnt cds at 1x speed. It would take hours to burn a cd and sometimes they
would turn out as duds. The blank discs only held 650 MB (which was quite a
bit back then) and were also expensive.

There was also a special type of blank disc, the re-writable blank disc which
was something like 10 bucks a pop at future shop.

I had a enterprising career in school at one point burning shared music mp3s
that I pulled from Napster and selling them to friends.

~~~
glouwbug
Were you selling Metallica by chance

~~~
Lammy
Infinite loop detected: Napster bad, but money good?

------
pmoriarty
When I record to DVDs, I always add error correction using dvdisaster.[1]

In addition, I sometimes have par2 files[2] on the DVD as well, though it's
probably better to just have additional dvdisaster ECC instead.

It's a good idea to periodically go through all your old backups and transfer
them to new media, or at least make sure the old media still works and start
recovery on them right away if they don't.

[1] - [http://dvdisaster.net/](http://dvdisaster.net/)

[2] -
[https://github.com/Parchive/par2cmdline](https://github.com/Parchive/par2cmdline)

~~~
sloshnmosh
I had pretty good luck using a program that could be programmed to extract all
readable sectors first and then go over and over damaged areas to try and
recover the data. I can’t recall the name of it but it had a picture of the
developers cat on the GUI. (If it is one of the ones you mentioned already I
apologize) Bad link on dvd disaster.

~~~
walterbell
Archive link:
[https://web.archive.org/web/20180428070843/http://dvdisaster...](https://web.archive.org/web/20180428070843/http://dvdisaster.net/en/index.html)

------
chenxiaolong
I've been meaning to try M-DISCs [0] after I found out that my BD drive
supports burning them. Apparently, they last longer than normal discs because
the drives burn "a permanent hole in the material, rather than changing the
color of a dye".

I don't use optical discs much anymore, but I still like the idea of archiving
things like family pictures on read-only media once in a while.

[0]
[https://en.wikipedia.org/wiki/M-DISC](https://en.wikipedia.org/wiki/M-DISC)

~~~
throwaway9d0291
M-DISC is mostly irrelevant these days unless you want to use DVD for some
reason.

The biggest benefit of M-DISC for DVDs was that it didn't use an organic dye,
as those dyes tend to decay over time. The dominant BD-R recording mechanism
(HTL) uses an inorganic recording medium so isn't affected by this problem.

There are differences in how BD-Rs are manufactured that can lead to big
differences in longevity [0] but there are regular retail BD-Rs that
outperform M-DISC in accelerated aging tests [1]. There are also DVD variants
that outperform M-DISC [2].

Also, M-DISC hasn't produced any evidence for their BD-R discs. For their DVDs
there were a few scientific studies they could point to that demonstrated
their longevity, for BD-R they have no such evidence.

[0]: [https://www.lne.fr/sites/default/files/inline-files/etude-
qu...](https://www.lne.fr/sites/default/files/inline-files/etude-qualite-
bd-r.pdf)

[1]: [https://www.lne.fr/sites/default/files/inline-files/etude-
qu...](https://www.lne.fr/sites/default/files/inline-files/etude-qualite-dvd-
bd-nov-2012-lambert.pdf)

[2]: [https://www.lne.fr/sites/default/files/inline-
files/syylex-g...](https://www.lne.fr/sites/default/files/inline-files/syylex-
glass-dvd-accelerated-aging-report.pdf)

~~~
Hamuko
So basically I want to buy Panasonic or Sony HTL BDs for archiving and store
them somewhere dark and dry?

Unfortunately that data is eight years old and I'm not even sure if Panasonic
and Sony even make BD-Rs anymore. Seeing a lot of out of stock Japanese
imports on Amazon.de for both of them. I can really only find Verbatim BD-Rs
and they didn't really perform that well in the comparisons.

I've actually been interested in BD archiving for a bit but haven't gotten
into it yet because of the initial costs. I have about 1.1 TB of data that I'd
like to archive for the long-term.

~~~
throwaway9d0291
They're both definitely making them. If you got to a retail store in Japan,
they'll have a HUGE section filled with BD-Rs and if you search Amazon JP you
can see that tons of them are in stock.

You can always import them yourself. Tenso and Buyee both work great.

I think it's just that the western market doesn't care for them much, so you
don't see anybody bothering to import them for you.

~~~
fomine3
x50 HTL BD-R (indicated as "non-organic") for video by SONY is sold on 3355
JPY. Possibly Amazon.co.jp supports international shipping.

[https://www.amazon.co.jp/dp/B01H8A8HH2/](https://www.amazon.co.jp/dp/B01H8A8HH2/)

------
daneel_w
I have friends who I remember always insisting on burning their CDs and DVDs
at the maximum speed the discs allowed for, and they all had problems with
their discs dying with time, some very soon, some after a year or two. No
matter what brand. Conversely, I never burned any of my CDs or DVDs at more
than half their advertised maximum speed, and so far I've yet to run into a
single disc dying from age. Some of these discs are now 20 years old, and they
still read/play fine.

My theory - and this is just a theory as I don't really know what's going on -
is that the dyes in CD-Rs and DVD-Rs after laser exposure slowly regress back
towards the original transparent state, and that very "fast" dyes combined
with a very short exposure time ("up to 52x speed!") emphasizes this problem,
while giving the dyes a longer exposure time prevents it by simply burning the
dye opaque beyond "recovery".

------
gitowiec
At the beginning of current year I dumped my data which I have written to CDs
in years 1997-99. The CD where dark green or blue, one or two were golden. All
this disks were written with 1x or 2x speed. Then I had access to the Yamaha
CDR102 burner which was SCSI. Burning disks then was a fragile process
involving a lot of mumbling prayers. I dumped to harddrive about 100 disks...
it was all MP3 and AVI files. One disk had a hole in its reflecting layer the
size of cross-section of a matchstick, nevertheless I could read whole disk. I
don't think I will throw away these disks. I will just put them in my
basement. Who knows how long that 2.5 inch harddrive will be in working
conditions :)

~~~
bfuclusion
I remember in 1998 ordering my Yamaha COD and waiting out in the cold
Minnesota snow to get it from the UPS driver, then paying 1$/disk. Total cost
per GB amortized over the life of the drive was like 2$ since a newer faster
model came out 3 months later. Now I get pissed if storage is more than about
0.04$/gb. Times have changed.

------
korethr
A thought occurred to me on a recovery method while reading this article: If
you had a disc that was marginal, where it might or might not read correctly
depending on the phase of the moon, would it be possible to do something like
take multiple raw images of the disc, perhaps using multiple different drives,
and collectively use the images so captured to isolate out the bad parts and
splice together a valid image file?

Or am I failing to grok the degree to which It's Complicated?

~~~
gruez
Yeah, apparently there's software that does that to get a rip that's identical
bit for bit.

[http://www.exactaudiocopy.de/en/index.php/overview/basic-
tec...](http://www.exactaudiocopy.de/en/index.php/overview/basic-
technology/extraction-technology/)

[http://www.accuraterip.com/](http://www.accuraterip.com/)

~~~
stordoff
For audio CDs, there's also CueTools, which can repair slightly damaged rips
(I assume it stores some parity information). I have a CD where that appears
to have either two slightly different pressings or a bad batch, and one has an
audible click at the end of one of the tracks. CueTools detects this error,
and lets me fix it.

------
Scoundreller
I’m surprised there’s nothing about storage conditions.

Is it the plastic or the metals breaking down? If it’s plastic, humidity
probably has a bigger impact.

Lower temps are almost always better. Freezer is good. Hard to say if an
oxygen absorber is helpful.

Or could sparge your container with nitrogen.

~~~
chiph
I still have some CDs from the early/mid 1980's that play, and I think this is
because of two reasons: 1) Not many people owned players back then, so
pressing plants weren't under much pressure from high demand, so pressing
quality was higher. 2) I stored them in their jewel cases oriented vertically
on the shelf, supported by the plastic fingers of the case - so no sagging
from being stored horizontally. And this was indoors, away from sunlight.

So far as home-burned CDs, they haven't lasted as well. Mostly because I
didn't take as good care of them - I didn't have $18 or more invested in them
(typical new music CD price in the 80's & 90's) so they were just tossed in a
drawer.

------
tomotomo
By coincidence, I'd been looking into the problem of bitrot and what options
exist. Hard drives are a starting point and last longer than removable discs.
If going for optical, M-DISC seems to be by far the best option.

[https://uncentered.saigonist.com/decentralize-your-data-
part...](https://uncentered.saigonist.com/decentralize-your-data-part-1.html)
[https://uncentered.saigonist.com/decentralize-your-data-
part...](https://uncentered.saigonist.com/decentralize-your-data-part-2.html)

------
jamesu
I still have a few spindles of CD-R's probably topping out at 15 years old now
- managed to burn copies of linux for some old machines earlier on in the year
though with no errors.

Really doubt I will end up using much more of them at this rate though besides
using them as "retro" coasters.

------
rawfan
I noticed that some CDs/DVDs are already going bad after very few years in the
early 2000s, so I put everything on harddisks, recovered broken stuff with
ddrescue and was done with writable optical media.

------
BuildTheRobots
Can anyone recommend encoding settings for archiving DVD-Video discs created
on a recorder?

I've taken dd images, but can't find a reasonable "archival" h265 profile that
doesn't come out larger than the original.

~~~
Lammy
I've been meaning to write up a page on how to do this, but basically:

\- Take an ISO rip and never delete it since any additional encoding is a new
derivative work of your data.

\- Run it through MakeMKV to get a Matroska file for each title

\- Assuming a video source (e.g. recorded TV shows or camcorder footage) use
QTGMC to deinterlace the video from 60 fields per second to 60 frames per
second. This will approximate the original look on today's screens by
simulating the slight delay in the dimming of a CRT's phosphors after the
electron beam excites them.

\- Crop the video if any black bars are present. Many DVDs have 8px of dead
area on the left and right edges because they are rooted in the D-1 4:2:2
standard and often have a program area resolution of 702 or 704x480:
[https://en.wikipedia.org/wiki/D-1_(Sony)](https://en.wikipedia.org/wiki/D-1_\(Sony\))

\- Convert the chroma from SD colorspace to HD colorspace to avoid them
looking washed-out on modern displays:
[https://en.wikipedia.org/wiki/Rec._601](https://en.wikipedia.org/wiki/Rec._601)

\- Decide how to handle the aspect ratio. People use "anamorphic" to mean
"widescreen DVD" but that's kinda a misnomer because all DVDs are anamorphic:
its 720x480 pixel resolution is 3:2, halfway between 16:9 and 4:3. Each title
sets a flag telling the display to stretch it ±18.6%, depending. You can leave
it like this, setting the same DAR flag, but I've come to prefer resizing it
myself to a square-pixel resolution since I'm usually cropping it anyway and
VapourSynth will do a way better job than most displays can do on the fly. I
also dislike the idea of throwing away horizontal pixel data by resizing 4:3
video down from 720x480 to 640x480, so some times I stretch it vertically
instead, to 720x540 (or 720x544 with 4px black along the bottom if you want to
follow the ATSC 3.0 HEVC recommendations).

\- Encode the video with x265. I have a personal "SD" tuning that I've been
working on and would love to share once I can get some example clips together
:)

\- Encode the probably-AC3 audio with FDK-AAC. I find it handles voices and
other things better than faac thanks to its low-pass step, but for very high-
bitrate sources (like concert DVDs) I disable that by using VBR-5:
[http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AA...](http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC)

\- Mux your new streams together into a new MKV, and take a moment to fill in
all the metadata fields the container provides. You can even attach a JPEG
named "cover.jpg" and have it display as the icon in Explorer!

~~~
walterbell
Thanks for the writeup! Would BD be much different? Do you recommend
converting x264 to x265 for Blu-Ray sources?

~~~
Lammy
BDs usually aren't interlaced or overscanned, so the hard part is done for you
:)

I do usually re-encode from from AVC to HEVC but with a more usual HD tuning.
Not mine, but check out
[https://docs.google.com/spreadsheets/d/1u9fKNsRcLgc-1oVV5GhB...](https://docs.google.com/spreadsheets/d/1u9fKNsRcLgc-1oVV5GhBgoPGO9vLpcn-x3NUgTmeC-0/edit#gid=0)

------
abeppu
> Sometimes, CD- and DVD-Rs were burned at high speeds with high error rates
> that were normally fixed on the fly by error-correcting code. This can make
> it more difficult for modern optical disc drives to read them, so try them
> on an older drive, if possible.

Does that mean drives were first made with relatively robust ECC, and they
just stopped using it for later drives? What would be the motivation to drop
that?

------
calyth2018
In my past, I've purchased some high quality CD-Rs used by studios. Not sure
if they made a difference though. I didn't see any definitive information with
a quick search.

I've long since abandoned using optical as a form of stroage...

------
walterbell
Is there good Linux software for cataloging offline media and identifying
duplicates? On Windows/Mac/iOS there is the venerable (since 2000)
[http://abemeda.com](http://abemeda.com).

------
at_a_remove
I always burned at the slowest possible speed, with all of the error-checking
if it was available, on the best media I could find. As a strategy, it largely
paid off. More expensive, more time-consuming, less frustrating later.

------
jccalhoun
last year I spent a while ripping all my burned disks to redundant harddrives.
I had to use isobuster on a couple but having multiple redundant backups helps
me sleep better at night.

------
Grazester
I dont know how my cheap burnt CD's from the early 2000's are still fine but
some of my pressed CD's are suffering from Disc rot!

~~~
daveslash
How common is Disc Rot for pressed CD's?

~~~
tobyhinloopen
I regularly buy 2nd hand audio CDs as old as the 80’s and never had a bad one

~~~
caseyohara
Probably survivorship bias as the only old CDs for sale today are in good
shape

~~~
lb1lf
-Still only anecdata, but I've been buying lots of music on CD since the late eighties, the oldest I know of was pressed in late 1983 sometime. (Which is only a year or so after the introduction of the CD anyway)

In sum, some 3,800 CDs. I ripped them all a couple of years ago - I had
problems with a handful, but EAC eventually got them all to disk. I examined
the troublesome ones, but no (visual) signs of disc rot.

------
mehrdadn
Anybody know how BDs fare?

~~~
zozbot234
Many BD-R's ought to fare quite well wrt. archival, with a better-behaving
substrate than CD-R or DVD-R. You may want to look for more detailed info to
ensure that this applies to your disks, though,

------
toolslive
vinyl records are having their revenge.

~~~
gruez
Isn't that trading one failure mode for another? While vinyl records won't rot
over time, they do wear down, and thus the sound quality deteriorates each
time you play it.

~~~
laumars
In theory, yes. But in practice it’s not at any rate that most people should
worry about. Plus some records are more durable than others.

One could extend the vinyl argument and say there’s no such thing as a storage
medium without a failure mode. Cassettes have problems, HDDs can fail, even
solid state systems only have a limited life. The best we can do is backup.

~~~
toolslive
> The best we can do is backup.

No. The best you can do is use mathematics to compensate. In essence represent
the data as a set of equations and generate extra ones that will be useful in
case you lose one. They have been doing this for decades in telecom/storage.

~~~
laumars
And as I already said, storage will always be subject to fail.

You can have 10 TB of parity for a 1 MB file but if that data isn’t
distributed then you’re still vulnerable.

So the problem is analog vs digital nor the lack of mathematics in vinyl; it’s
that ultimately any form of storage media requires a physical device and
physical devices are bound to the problems of the physical world.

This, by the way, is also why Amazon has multiple data centres in any given
region. Why backups should always be stored off site, and why DR solutions are
based in different physical premises.

