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Pinholes in the metallic layer of a CD no longer contain music, Split from Topic ID #96812 (TOS #5)
jayess
post Sep 4 2012, 05:44
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QUOTE (Satellite_6 @ Sep 3 2012, 20:37) *
CD's!!!!!!!!!! Obviously the way to go.


You're absolutely correct, CD's are the way to go, but they aren't the perfect solution either. Most of my collection was bought used and I'm always shopping for new (used) stuff, but it's crazy to see how bad CD's deteriorate. That old stuff from the 80's and 90's, especially the discs with the chrome tops, hold them up to a light source and it's crazy to see how many of them have pinholes, which means there's no longer any music in that hole. And I'm talking about discs that in many cases don't have a scratch on them.
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greynol
post Sep 4 2012, 06:13
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There was never any "music" in the spot where the pinhole is to begin with. The data is distributed.

There's a post somewhere on the forum about how large a hole can theoretically be before error-free data can no longer be recovered.

Feel free to google CIRC if you feel so inclined. smile.gif


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jayess
post Sep 4 2012, 13:23
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QUOTE (greynol @ Sep 4 2012, 00:13) *
There was never any "music" in the spot where the pinhole is to begin with. The data is distributed.

There's a post somewhere on the forum about how large a hole can theoretically be before error-free data can no longer be recovered.

Feel free to google CIRC if you feel so inclined. smile.gif


Really?

Then why do these "pinhole" discs always fail Accuraterip or otherwise get poor rip scores?

The clue is when they start doing frames during ripping.

Furthermore, until I created a database that I could access when shopping I made the mistake of buying more than one copy of several discs (at least 25 or so) mistakenly, not realizing I already had it. That happens if you try to keep 2,000 titles or so in your head. And the results of getting to test two identical discs, one with pinholes and one without, is the pinholes are in fact degradation.

This post has been edited by jayess: Sep 4 2012, 13:29
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Porcus
post Sep 4 2012, 13:30
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QUOTE (jayess @ Sep 4 2012, 14:23) *
Then why do these "pinhole" discs always fail Accuraterip or otherwise get poor rip scores?


Because a CD with its reflective layer damaged, seldom is ruined just at a single tiny spot and nowhere else, and if so should be, then most of us would just be happy about the AR match rather than looking for pinholes?


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jayess
post Sep 4 2012, 13:48
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QUOTE (Porcus @ Sep 4 2012, 07:30) *
QUOTE (jayess @ Sep 4 2012, 14:23) *
Then why do these "pinhole" discs always fail Accuraterip or otherwise get poor rip scores?


Because a CD with its reflective layer damaged, seldom is ruined just at a single tiny spot and nowhere else, and if so should be, then most of us would just be happy about the AR match rather than looking for pinholes?


As I understand it, a CD is made up of minutes, seconds, and frames, with 75 frames being equal to one second of music. And CD players treat errors (pinholes, scratches that don't cause skips etc.) as silence, so by just putting a pinhole disc in a player, you're not going to hear the errors. On the other hand, with Accuraterip looking for every single CRC, then pinholes start becoming quite obvious from my experience.
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2Bdecided
post Sep 4 2012, 14:35
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QUOTE (greynol @ Sep 4 2012, 06:13) *
Feel free to google CIRC if you feel so inclined. smile.gif
He might get on better googling CRC?

You're unlikely to get just one pinhole, and it's unlikely that every actual gap is easily visible - so by the time you can see pinholes in your CDs, it's possible there are uncorrectable read errors too (due to clusters of gaps that the error correction can't fix).

That said, my first CD, manufactured by PDO in 1988 is visibly wrecked - yet all but one track passes AccurateRip (track 5 out of 10, interestingly - even though the damage is mostly starting at the edge and progressing inwards).

Cheers,
David.
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greynol
post Sep 4 2012, 15:45
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QUOTE (2Bdecided @ Sep 4 2012, 06:35) *
He might get on better googling CRC?

If he could be bothered to do even that much.


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jayess
post Sep 4 2012, 16:10
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QUOTE (greynol @ Sep 4 2012, 09:45) *
QUOTE (2Bdecided @ Sep 4 2012, 06:35) *
He might get on better googling CRC?

If he could be bothered to do even that much.


I did run some Google searches Greynol and they produced nothing more than "opinions."

I have this question for you: I give you two identical CD's of which you can keep one for your music collection, one has pinholes and one doesn't, which one would you keep (or be willing to pay for)?

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greynol
post Sep 4 2012, 16:28
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QUOTE (jayess @ Sep 4 2012, 08:10) *
I have this question for you: I give you two identical CD's of which you can keep one for your music collection, one has pinholes and one doesn't, which one would you keep (or be willing to pay for)?

Your question is completely irrelevant to the fact that you still don't have the faintest idea how data is organized on a CD.

I'd like to think the article in wikipedia would have been a result.

This post has been edited by greynol: Sep 4 2012, 16:28


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jayess
post Sep 4 2012, 16:29
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QUOTE (greynol @ Sep 4 2012, 10:28) *
QUOTE (jayess @ Sep 4 2012, 08:10) *
I have this question for you: I give you two identical CD's of which you can keep one for your music collection, one has pinholes and one doesn't, which one would you keep (or be willing to pay for)?

Your question is completely irrelevant to the point that you still don't have the faintest idea how data is organized on a CD.

I'd like to think the article in wikipedia would have been a result.


About those CRC's...

"Hold the CD up to a light. If you can see light through scratches or pinholes in the label, you have label-side scratches.

This damage cannot be repaired. The reflective layer has been removed. No optical pickup, no matter how good it is, can ever read data without a reflective layer present.
"

http://wiki.slimdevices.com/index.php/Repairing_damaged_CDs
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greynol
post Sep 4 2012, 16:31
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CIRC

I didn't know Logitech was in charge of wikipedia.

This post has been edited by greynol: Sep 4 2012, 16:33


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jayess
post Sep 4 2012, 16:38
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QUOTE (greynol @ Sep 4 2012, 10:31) *
CIRC

I didn't know Logitech was in charge of wikipedia.



QUOTE (greynol @ Sep 4 2012, 00:13) *
There was never any "music" in the spot where the pinhole is to begin with. The data is distributed.


Which is it?
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greynol
post Sep 4 2012, 16:39
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There is no contradiction in describing Cross-Interleaved Reed-Solomon Coding as data being distributed. There is no contradiction in saying music does not exist at a fixed point either.

At this point I don't care what you choose to do with this information, just leave it out of this discussion. I suggested you research the concept on your own time in order to keep the discussion from getting bogged down with debate, especially one fueled with anecdotes. Yet we got this anyway. rolleyes.gif


My take on the actual topic at hand: Aren't itunes purchases DRM-free? Regardless, buyer be aware!
(EDIT: No longer relevant due to thread split)

This post has been edited by greynol: Sep 5 2012, 04:27


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2Bdecided
post Sep 4 2012, 19:25
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QUOTE (jayess @ Sep 4 2012, 16:29) *
About those CRC's...

"Hold the CD up to a light. If you can see light through scratches or pinholes in the label, you have label-side scratches.

This damage cannot be repaired. The reflective layer has been removed. No optical pickup, no matter how good it is, can ever read data without a reflective layer present.
"

http://wiki.slimdevices.com/index.php/Repairing_damaged_CDs
That's explaining that you can't polish those label-side scratches away (as opposed to read-side scratches, that can often be polished away). It's not saying whether the error-corrected data will be recoverable or not. (though presumably you wouldn't get the polish out unless there were read errors).

As greynol says, you really need to understand how CDs work. They are designed so that a single reasonably narrow radial scratch is perfectly recoverable. It does not change the output audio data at all. It is undetectable on the digital output of a CD player.

Cheers,
David.
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jayess
post Sep 4 2012, 20:22
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QUOTE (2Bdecided @ Sep 4 2012, 13:25) *
QUOTE (jayess @ Sep 4 2012, 16:29) *
About those CRC's...

"Hold the CD up to a light. If you can see light through scratches or pinholes in the label, you have label-side scratches.

This damage cannot be repaired. The reflective layer has been removed. No optical pickup, no matter how good it is, can ever read data without a reflective layer present.
"

http://wiki.slimdevices.com/index.php/Repairing_damaged_CDs
That's explaining that you can't polish those label-side scratches away (as opposed to read-side scratches, that can often be polished away). It's not saying whether the error-corrected data will be recoverable or not. (though presumably you wouldn't get the polish out unless there were read errors).

As greynol says, you really need to understand how CDs work. They are designed so that a single reasonably narrow radial scratch is perfectly recoverable. It does not change the output audio data at all. It is undetectable on the digital output of a CD player.

Cheers,
David.


We're not discussing it in the context of playing the music, we're discussing it in the context of ripping the music. How is error correction going to replace something that isn't there? Sure, it can create silence in place of the error and blend it into the track, but again where is the data that was in what is now a pinhole?
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[JAZ]
post Sep 4 2012, 21:53
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QUOTE (jayess @ Sep 4 2012, 21:22) *
We're not discussing it in the context of playing the music, we're discussing it in the context of ripping the music. How is error correction going to replace something that isn't there? Sure, it can create silence in place of the error and blend it into the track, but again where is the data that was in what is now a pinhole?


You really should read the information you're told to read.

For each 8 bits stored in a CD, there is 14 pits/valleys, and this data is not stored in a strictly sequential way.

No one is saying that data can be recovered in every case. What is being said is that the CD layer (i.e. the physical data on a CD) was designed from the begining to be fault tolerant.
Later on, with CD-Data, this was improved and added still more data recovery tools (Which is the reason why an 80 minutes CD stores only 740MB while 80 min * 60min/sec * 176.4KB/s = 807.5MB)
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db1989
post Sep 5 2012, 00:09
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Split as a great example of why ToS5 exists, I think.
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greynol
post Sep 5 2012, 02:30
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QUOTE ([JAZ] @ Sep 4 2012, 13:53) *
For each 8 bits stored in a CD, there is 14 pits/valleys, and this data is not stored in a strictly sequential way.

That's EFM, not CIRC. There is no redundancy for error correction there, rather it is there to prevent pit-land combinations that may be confused with other pit-land combinations. CIRC is where there are two levels of redundancy, the second of which, IIRC is distributed. Again(!) this distribution is done to protect against radial scratches and, yes(!) those pesky pin-holes.

When the data can't be recovered, linear interpolation is done (different from silence, despite what armchair experts will tell you). When interpolation can't be done then silence is substituted until data can be acquired again.

Do with this as you will.




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Glenn Gundlach
post Sep 5 2012, 04:46
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QUOTE (jayess @ Sep 4 2012, 07:29) *
About those CRC's...

"Hold the CD up to a light. If you can see light through scratches or pinholes in the label, you have label-side scratches.

This damage cannot be repaired. The reflective layer has been removed. No optical pickup, no matter how good it is, can ever read data without a reflective layer present.
"

http://wiki.slimdevices.com/index.php/Repairing_damaged_CDs


You know you're being kind of snotty. Greynol is trying to get you to find out how the data is arranged on a CD. You seem to think it's like an LP so a hole is a gap in the data. It is but unlike the LP, there is redundancy built in. I seem to recall in the early days one of the tests was how big a hole could be drilled in a CD before you lost data and it was around 1/8 of an inch - a lot bigger than your pinholes. Would I be willing to buy a disc with visible pinholes? It wouldn't bother me at all.

If you bother to look up and understand how a CD works, you'll find it was done by pretty smart people for use by pretty careless people. The discs are quite tolerant of abuse on the bottom side (where it's played from ) and the label side is more fragile though I've only wrecked one disc in 29 years. BTW ALL the discs I bought in the '80s still play fine. The oldest is from April '83.

G
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jayess
post Sep 8 2012, 23:34
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QUOTE (Glenn Gundlach @ Sep 4 2012, 22:46) *
QUOTE (jayess @ Sep 4 2012, 07:29) *
About those CRC's...

"Hold the CD up to a light. If you can see light through scratches or pinholes in the label, you have label-side scratches.

This damage cannot be repaired. The reflective layer has been removed. No optical pickup, no matter how good it is, can ever read data without a reflective layer present.
"

http://wiki.slimdevices.com/index.php/Repairing_damaged_CDs


You know you're being kind of snotty. Greynol is trying to get you to find out how the data is arranged on a CD. You seem to think it's like an LP so a hole is a gap in the data. It is but unlike the LP, there is redundancy built in. I seem to recall in the early days one of the tests was how big a hole could be drilled in a CD before you lost data and it was around 1/8 of an inch - a lot bigger than your pinholes. Would I be willing to buy a disc with visible pinholes? It wouldn't bother me at all.

If you bother to look up and understand how a CD works, you'll find it was done by pretty smart people for use by pretty careless people. The discs are quite tolerant of abuse on the bottom side (where it's played from ) and the label side is more fragile though I've only wrecked one disc in 29 years. BTW ALL the discs I bought in the '80s still play fine. The oldest is from April '83.

G


And you're being rather dense, along with some others. As I said, the discs with pinholes can't pass muster when it comes to ripping them with Accuraterip verification. You guys can sing and dance all day about "playing the discs," but again, that's not the issue. The issue is ripping music with no loss of data due to pinholes.

Let's see you back up your claim. Rip a music CD, record the Accuraterip results, then drill a 1/8" hole, or better yet multiple holes, in it and record the results again. Post the whole thing in a Youtube video. That'll get my attention and prove you guys are doing more than blowing air into a paper bag.
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greynol
post Sep 9 2012, 00:04
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If you go back to your original post you will see that I addressed your erroneous assumption about how data is laid out on a CD.

Instead of being gracious about the correction, you've decided to play a game of bait and switch.

It isn't us who are looking dense in this discussion, just as sure as you aren't able to rip some of your discs. wink.gif

This post has been edited by greynol: Sep 9 2012, 00:06


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greynol
post Sep 9 2012, 01:32
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QUOTE (jayess @ Sep 8 2012, 15:34) *
You guys can sing and dance all day about "playing the discs," but again, that's not the issue. The issue is ripping music with no loss of data due to pinholes.

We made no distinction between ripping and playing because there is no distinction. The data doesn't magically rearrange itself because the disc was put into a cd-rom drive.


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Tahnru
post Sep 9 2012, 03:05
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QUOTE (jayess @ Sep 8 2012, 20:57) *
That would depend on if you were using the ASIO, Wasabi, or Direct Sound driver.


None of these technologies has anything to do with RAID.

Let's be honest here, what are you looking for? Are you avoiding doing research because of pride? Are you just lazy and can't be bothered to understand the questions you're asking?

There is no real discussion happening here.
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EagleScout1998
post Sep 9 2012, 03:06
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Not that it would add anything important to the debate, but I have, in the past, accurately ripped CDs with pinholes. The fact that they are present doesn't automatically render the disc a coaster.
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jayess
post Sep 9 2012, 03:14
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QUOTE (EagleScout1998 @ Sep 8 2012, 21:06) *
Not that it would add anything important to the debate, but I have, in the past, accurately ripped CDs with pinholes. The fact that they are present doesn't automatically render the disc a coaster.


My own personal experience: since I've started doing the so-called light test inspection for holes instead of just looking for scratches, my failure rate on buying used discs has went to zero. And I buy a lot of them; probably at least 50 per month.
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