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Author Topic: 3 secure rips, 1 differs  (Read 1917 times)

Von

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3 secure rips, 1 differs
« on: October 22, 2011, 05:08:18 pm »

I rip in secure mode.
I ripped an album three times, all of them reported with no re-tries. The resulting wav files all have matching md5 checksums respectively, except for one track from one rip.

I don't have any tools installed for bit comparing the files, but I trust the md5 sums.

How can the file be different from the other two?

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Von

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Re: 3 secure rips, 1 differs
« Reply #1 on: October 28, 2011, 04:22:57 pm »

I just wanted to add that a fourth rip matched the third rip. So I have two different sets of two identical rips. MC16 reported no re-tries in all cases. The CD in question doesn't have a single scratch.

Could this be a case of some section being hard to read, but always being read as either X or Y, without MC16 noticing any problem?

I haven't been able to hear any flaws or differences. But then again I have no exact position to listen to since no unreliable data was reported.

For those of you who want to say "if you can't hear any difference, why bother?" - I get your point. But I would still like to know what could be causing this.
 :)
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Frobozz

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Re: 3 secure rips, 1 differs
« Reply #2 on: October 28, 2011, 05:18:47 pm »

The same can happen when using EAC (Exact Audio Copy) as well.  I had one disc that did that with EAC.  Rip it with drive X and it would get one result.  Rip it with drive Y and get a different result.  Both rips reported no errors.  CRCs for one track were different.  The differences were consistent across re-rips with each drive.  Weird.  I've only run across one disc that behaved like that.  EAC has AccurateRip so I was able to figure out which rip was the right one.

Try ripping in MC to a CUE and use CUETools to try to verify which of your rips is right.  CUETools might be able to tell you which one is good.
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Von

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Re: 3 secure rips, 1 differs
« Reply #3 on: October 28, 2011, 06:15:36 pm »

The same can happen when using EAC (Exact Audio Copy) as well.  I had one disc that did that with EAC.

That has happened to me as well with EAC.

Try ripping in MC to a CUE and use CUETools to try to verify which of your rips is right.  CUETools might be able to tell you which one is good.

Thanks for the tip. What exactly can CUETools do to say which rip is more correct?

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Frobozz

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Re: 3 secure rips, 1 differs
« Reply #4 on: October 28, 2011, 07:13:33 pm »

CUETools can compare the rip against AccurateRip data to identify which rip is good.  CUETools isn't perfect.  If the CD has a pre-gap before the first track then the comparison can be off.  So it's possible for CUETools not to be able to verify a rip even if the rip is good.

You can also use CUETools to generate a fake CUE sheet from the individual tracks.  Then you can use the fake generated CUE sheet to attempt to verify a rip.
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Listener

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Re: 3 secure rips, 1 differs
« Reply #5 on: October 28, 2011, 08:04:45 pm »

I rip in secure mode.
I ripped an album three times, all of them reported with no re-tries. The resulting wav files all have matching md5 checksums respectively, except for one track from one rip.

Before jumping to any conclusions, you should compare the audio content of the files rather than the entire WAV files.  The non-audio portion of the WAV files might be different.  I believe that EAC and Foobar may have commands for comparing the audio content of WAV files.

Bill
 

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