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EAC: Some Test/Copy CRC values don't match but all tracks play fin, does CRC match really matter or is it just an obsessive exercise
derty2
post Aug 3 2013, 03:32
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I ripped a 2-disc compilation to FLAC(tracks+.cue) with EAC .
Both discs were clean, shiny and new looking, and I cleaned away fingerprints and such with tissue paper before placing in drive .

My EAC options were:
Burst Mode, Get drive offset info from AccurateRip database, Append Gaps To Previous Track

My EAC actions for each disc were done in 3 steps:
[1] Detect Gaps
[2] Create CUE Sheet > Multiple WAV Files With Gaps (Noncompliant)
[3] Test & Copy Selected Tracks

For both discs, my observations of EAC running through the rip in Burst Mode looked normal; I did not see EAC stumble or slow down to a crawl at any stage.
I dragged the ripped tracks into foobar2000 and played . . . all sounded normal; none of the tracks had audible errors.

Looking at the EAC log, I notice that the TEST CRC and COPY CRC for a couple of tracks did not match.
Does it really matter? Does it really have any importance?
I notice many many people get hung up about "accuracy" and "perfection" with their EAC ripping but at the end of the day it all seems like a an obsessive exercise to me.

What I am trying to say here is that, fundamentally, if EAC has managed to rip the whole disc at a brisk pace and you have all tracks sitting on your hard drive as FLAC files and you drag the lot into foobar2000 and play them and they all sound fine . . . . . then that is that, the job is done, you have what you wanted . . . . all other aspects come across to me as an obsessive hair-splitting exercise.

Furthermore, I would be quite happy to burn my tracks (using the CUE) back to an audio CD and be satisfied . . . irrespective of the LOG info telling me some tracks had mis-matching CRC values.

I find the obsession with "perfect" a big waste of time . IMHO, the only thing that is "perfect" is the original physical manufactured Audio CD; everything else is a less-than-perfect copy which is aurally indistinguishable from the original.
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nastea
post Aug 3 2013, 04:07
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"the only thing that is "perfect" is the original physical manufactured Audio CD; everything else is a less-than-perfect copy"
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When, at the end of a rip EAC says: All tracks accurately ripped
you got a perfect rip, right?
In my opinion, an error free rip on the harddrive is just as perfect as the original cd.

For every cd you once bought, you should be able to copy the music error free to the HDD.
I'm hoping AccurateRip will someday replace misread data with correct data. smile.gif

(sorry, the Quote button didn't work)

This post has been edited by nastea: Aug 3 2013, 04:10
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gib
post Aug 3 2013, 05:02
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I'm curious, what exactly is the purpose of this post? There's really no question or help needed here. It sounds like you're really just fishing for external validation; someone to tell you it's ok if you are satisfied with a rip that is probably not an accurate bit-for-bit copy of the disc.

Well, hey, if you are satisfied with a rip that is probably not accurate, that's a-ok.

I hope that helps.
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AndyH-ha
post Aug 3 2013, 05:43
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I have yet to find any problems through listening if the test and copy CRC values agree. Thus, they are the easiest way to be sure there are no problem errors if either, the computer is not on-line to check, or if the CD isn't found in the AccurateRip database.

On the other hand, I get the data off a great many CDs using a computer that is not on-line. When the calculated values don't match I try again on another optical drive, and if that doesn't bring satisfaction, on a third drive. When the calculated values still won't agree, I have to spend much more time by listening to the tracks.

The majority of those come out alright. If there are errors, they are not significant enough to hear -- or there may be a slight crackle or two from one or two missing samples, something I probably would not notice if I wasn't listening for problems. I don't care about such minor discrepancies.

There are however, occasionally tracks with much more serious problems, a BIG unpleasant noise, or many such noises, from missing samples and/or snippets simply missing in silence. These problems are more likely when the drive has slowed considerably while extracting some, or even most, of the CD's content, but that slowing down isn't a definite sign, either. The tracks may still come out fine (or even with matching CRC values) from a very slow Test & Copy run.

... and, sometimes when the extraction speed is high, the non-matching CRCs are the only sign of a serious problem.
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mjb2006
post Aug 3 2013, 09:03
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QUOTE (derty2 @ Aug 2 2013, 20:32) *
[1] Detect Gaps
[2] Create CUE Sheet

No need for the first step. When EAC creates a cue sheet, it does a gap detection pass automatically so it can put in the correct INDEX 00 values. The values won't show up in the main window or log file, but they are cached for any additional cue sheet generation until you eject the disc.

Once you're confident EAC is configured to use a good gap detection method (one that gives you reasonable values and isn't too slow), you really don't need to do it anymore, and I suggest re-enabling Beginner mode. This really needs to be changed to eliminate the word "beginner", because it has nothing to do with how advanced you are, but rather whether you have extremely unusual ripping needs.

Manual gap detection is mainly for examining CD-Rs that you suspect have been burned in TAO mode, where the burner has added extra silence between the tracks. And you'd only want to find out if they exist if you plan to remove those gaps during the rip, which also means foregoing the use of AccurateRip. So, if you want to use AccurateRip, or you want to remove those gaps after the rip, or if you're ripping CD-Rs you know are burned in DAO mode, or if you're ripping ordinary pressed CDs, then manual gap detection has no usefulness, as far as I can tell.

This post has been edited by mjb2006: Aug 3 2013, 09:17
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derty2
post Aug 3 2013, 09:31
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Thanks everybody for the answers so far +++

I would like to reinforce my initial post with a real-life example:
QUOTE
* Put an Audio CD in drive.

* Run EAC 1.0beta3 Setup Wizard.

* Choose to install no optional components (uncheck all) ... ie: No "freedb Metadata Plugin", No "GD3 Metadata Plugin", No "CDRDAO", No "FLAC", No "AccurateRip", No "CTDB Plugin".

* Immediately close "Welcome to the EAC setup wizard" window

* EAC Main GUI opens ... the Drive and the Audio CD data have automatically loaded

* Action 1: Detect Gaps .. 'Detect Gaps' window runs ... operation successful

* Action 2: Create CUE Sheet > Multiple WAV Files With Gaps (Noncompliant) ... dialog window opens ... file saved to "C:\Test EAC\Unknown Title.cue" ... operation successful

* Action 3: Test & Copy Selected Tracks > Uncompressed ... 'Extracting Audio Data' window runs briskly to completion and I press the 'OK' button ... 'Status and Error Messages' window self-opens and I press 'Create Log' button and file is saved to "C:\Test EAC\Unknown Artist - Unknown Title.log" and I close this window.

* Looking at EAC main GUI before closing, I view the 'Read CRC' and 'Test CRC' columns; they are identical for every track.

* Looking at the output LOG file, I see "No errors occurred" at the end of the file.

* Looking at the output directory, all tracks are auto-saved by EAC as "C:\Test EAC\01 Track01.wav|02 Track02.wav|03 Track03.wav|..."

* Run foobar2000 audio player, create a new playlist and drag in all the WAV files and play . . . all tracks sounds great!


As far as I am concerned, for all practical purposes, I have a perfect lossless rip of the tracks from this CD, the tracks are aurally perfect, and aurally identical to what is on the CD!
I did not give one shit about configuring anything . . . not one thing, nothing, zilch.
As I said before in my initial post, people waste their lives over tweaking this software (EAC) and this "perfect accurate" phenomenon but in the end they get NOTHING MORE than what I got!
From a userland perspective, the vast majority of articles, discussions, and technical guidance about EAC are nothing more than obsessive hair-splitting time-wasting brain-fucking exercises.
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greynol
post Aug 3 2013, 09:52
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The practical benefit of secure ripping is that you have a reasonable assurance that there will not be audible problems without having to listen to the entire extraction. Perhaps this doesn't mean much to those who only rip a couple of titles every once in a while.

Let's not forget that a secure method of ripping may provide rips that are free of audible defects which may not have occurred otherwise. This obviously won't happen with burst t&c, but that is not the only method of secure ripping.

This post has been edited by greynol: Aug 3 2013, 10:03


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