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WAV and ISObuster with scratched CDs
markf
post Nov 1 2006, 00:06
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I'm ripping my CD collection to WAV files. I chose WAV because I would prefer to have an absolute copy of the CD without having to compress and decompress, although I did consider FLAC. Anyway, some of my CDs are kind of old and will not make an entirely errorless copy with EAC. If I used ISObuster to make a copy of the original CD, burned the image to CD, and ripped the new CD using EAC, what would be the significance as far as quality? I seem to almost always get scratches out using ISObuster and it makes WAV files anyway.

I'm curious because I saw another post here (http://www.hydrogenaudio.org/forums/index.php?showtopic=45164&hl=ISObuster) by Cosmo claiming that ISObuster images are not perfect images of the CD. ("An image extracted by ISObuster, even though it reports that a 100% successful copy was made, cannot be assumed to be a correct 1:1 copy of the original audio data.")

Can someone please explain this further? I prefer not to take mild abrasives, toothpaste, etc. to these CDs. Thanks.

Mark
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dreamliner77
post Nov 1 2006, 00:26
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Isobuster will not give you a perfect rip. You will be making a copy of the cd with all the skips and then trying to rip this new copy that will not appear to have physical errors.

EAC is designed for audio extraction, stick with that.


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markf
post Nov 1 2006, 19:29
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QUOTE (dreamliner77 @ Oct 31 2006, 15:26) *
Isobuster will not give you a perfect rip. You will be making a copy of the cd with all the skips and then trying to rip this new copy that will not appear to have physical errors.

EAC is designed for audio extraction, stick with that.


I'm not quite following you, though. This is similar to the other poster ("Cosmo"). I understand the conclusion but not how you got there.

For instance, I had a CD with one track that skipped. I used ISObuster to rip the CD and the skipping track no longer skipped in the problem location and everything sounded fine. The resulting tracks were also WAV files on my computer. ISObuster (1) eliminated the problem skip and (2) I got WAV files. Burning the WAV files to CD and then re-ripping the new CD with EAC, everything sounded fine.

The CD that I burned from the resulting ISObuster files did not have the skips from the original CD and the new CD had no physical errors as it was brand new. I'm not trying to be difficult, just trying to understand what's going on.

By the way, Neil Peart rocks.

Mark
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greynol
post Nov 1 2006, 19:36
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You're working under the assumption that Isobuster ripped the disc without errors. How do you know this to be true?

As a crude sanity check, have you used Isobuster to rip an image twice and compared the results?

This post has been edited by greynol: Nov 1 2006, 19:36


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markf
post Nov 1 2006, 23:15
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QUOTE (greynol @ Nov 1 2006, 10:36) *
You're working under the assumption that Isobuster ripped the disc without errors. How do you know this to be true?

As a crude sanity check, have you used Isobuster to rip an image twice and compared the results?


I'm not sure that ISObuster would rip the CD without error, as would be reported by EAC. ISObuster just rips and it's over. If there are problem spots that it cannot resolve, it gives you the option of how to proceed. I have not ripped a CD with ISObuster twice and compared the results. Would this yield wildly different results? I'll try it later today.

From an aural perspective, the CD starts out scratched and the affected file reflects this. After using ISObuster, there is no scratch and the files sound fine (and they're WAV).

I understand now from both of you that when I rip the CD using ISObuster, I am potentially (probably) recording errors. However, it sounds fine. How can it sound fine and still have errors? (I swear I'm not trying to be a pest; I just don't understand)

If I stuck with EAC as advised earlier and I had a scratched CD, am I then back to toothpaste and drugstore/hardware store compounds that coincidentally fix scratch CDs? I can research those methods on my own; I just wondered what the answer is and wish I had been more careful with those stupid CDs. Thanks.

Mark
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dreamliner77
post Nov 1 2006, 23:21
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QUOTE (markf @ Nov 1 2006, 18:15) *
How can it sound fine and still have errors? (I swear I'm not trying to be a pest; I just don't understand)


The CD standard allows for errors (C1, C2). A cd player is designed to interpolate when there are errors. So, even though you can't hear the error, they can still be there.


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markf
post Nov 1 2006, 23:36
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QUOTE (dreamliner77 @ Nov 1 2006, 14:21) *
QUOTE (markf @ Nov 1 2006, 18:15) *
How can it sound fine and still have errors? (I swear I'm not trying to be a pest; I just don't understand)


The CD standard allows for errors (C1, C2). A cd player is designed to interpolate when there are errors. So, even though you can't hear the error, they can still be there.


OK, thanks for the info and putting up with all my questions.

Mark
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bhoar
post Nov 1 2006, 23:42
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Mark-

EAC and ISO Buster are doing different things.

EAC tries to do what it is named for: EXACT audio copy. If errors are encountered, it will continue to retry to get the original audio data with varying levels of thoroughness and results, depending on the disc, drive and the settings chosen in EAC.

ISO Buster, on the other hand, does not care if the ripped data is accurate. If unrecoverable errors are encountered, ISO Buster is probably attempting to fill them in with average values so that the errors in the rip are less likely to be audible. Note that EAC has this capability, in post-processing, but it's a manual cleaning process, as the author figures the user would want to listen and decide where and when glitch-removal algorithms should be applied.

Within the context of audio extraction, EAC is a more complex tool. However, proper configuration for your environment and needs is essential in getting great results.

If you don't care about the "exactness" of the extraction and are happy if the tool does its best to cover up any data errors from the CD, then ISO Buster will probably fit the bill for you.

And there's really no reason I can think of to rip with ISO Buster, then use EAC. I can think of reasons to rip with EAC, perform a CD image extraction, and then mount the WAV as a virtual CD for use other tools (e.g. iTunes integration, or checking EAC image rip againt Accurate RIP with a tracks extraction)

Shorter version: ISO Buster automatically fixes errors for you, which means most times the fixes are close to, but not exactly, the data that was not readable. EAC allows you to fix errors if you want to do so. If you've configured EAC well and run the right types of extractions, they'll take longer, but it many cases the rip that had errors covered up by ISO Buster would be extracted without errors in EAC.

-brendan

This post has been edited by bhoar: Nov 1 2006, 23:45


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markf
post Nov 3 2006, 06:55
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QUOTE (bhoar @ Nov 1 2006, 14:42) *
Mark-

EAC and ISO Buster are doing different things.

EAC tries to do what it is named for: EXACT audio copy. If errors are encountered, it will continue to retry to get the original audio data with varying levels of thoroughness and results, depending on the disc, drive and the settings chosen in EAC.

ISO Buster, on the other hand, does not care if the ripped data is accurate. If unrecoverable errors are encountered, ISO Buster is probably attempting to fill them in with average values so that the errors in the rip are less likely to be audible. Note that EAC has this capability, in post-processing, but it's a manual cleaning process, as the author figures the user would want to listen and decide where and when glitch-removal algorithms should be applied.

Within the context of audio extraction, EAC is a more complex tool. However, proper configuration for your environment and needs is essential in getting great results.

If you don't care about the "exactness" of the extraction and are happy if the tool does its best to cover up any data errors from the CD, then ISO Buster will probably fit the bill for you.

And there's really no reason I can think of to rip with ISO Buster, then use EAC. I can think of reasons to rip with EAC, perform a CD image extraction, and then mount the WAV as a virtual CD for use other tools (e.g. iTunes integration, or checking EAC image rip againt Accurate RIP with a tracks extraction)

Shorter version: ISO Buster automatically fixes errors for you, which means most times the fixes are close to, but not exactly, the data that was not readable. EAC allows you to fix errors if you want to do so. If you've configured EAC well and run the right types of extractions, they'll take longer, but it many cases the rip that had errors covered up by ISO Buster would be extracted without errors in EAC.

-brendan


Brendan,

Thanks for that explanation. I care about having an exact copy but I haven't been clear on EAC and ISObuster until I posed the question in this forum. I've got a better understanding now and I appreciate the responses.

Now, you said "that EAC has this capability [to fill in unrecoverable errors], in post-processing, but it's a manual cleaning process, as the author figures the user would want to listen and decide where and when glitch-removal algorithms should be applied." Could you point me to a link or manual where I could read more about this? Thanks.

Mark
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