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AccurateRip approves normalized tracks. Detect if track is normalized?, [TOS #6: was “Detect Normalization” in G/Aud: no context, wrong board]
Hyouga
post Jun 12 2012, 12:48
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Hi

I have a question regarding normalization.

I've noticed AccurateRip gives "Accurately Ripped" results for normalized tracks.

Is there any way to detect if a track have been previously normalized? (Without taking .log in consideration)

Thanks.
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Porcus
post Jun 12 2012, 13:40
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QUOTE (Hyouga @ Jun 12 2012, 13:48) *
I've noticed AccurateRip gives "Accurately Ripped" results for normalized tracks.


Hard to help as long as you have not specified whether you are retro-checking using e.g. CUETools, whether you have burned a CD of normalized tracks and re-ripped, whether you have selected to apply normalization in the course of ripping (in which case you would effectively check first and normalize later) or whether you have verified that the tracks are indeed normalized (not merely tagged).


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Hyouga
post Jun 12 2012, 13:53
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Yes I should have been more specific.

I use CUETools for checking the files. However mine is not a specific question about CUETools, I'm asking if there's a known procedure or application to detect a posteriori if a sound file have been modified via normalization.
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pdq
post Jun 12 2012, 14:01
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If by normalization you mean increasing or decreasing the volume then the only way to detect it is by comparing against the original.
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spoon
post Jun 12 2012, 14:02
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A change in volume of the track would give a different CRC. If the track was clipping and no actual normalization took place the CRC would stay the same.


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Hyouga
post Jun 12 2012, 18:00
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Yes, in theory, that should be true, but I've ripped a bunch of normalized CDs, I've tested a downloaded normalized rip and the results are consistent.

I don't know the reasons of this, if the responsible is EAC, AccurateRip or that the verification matches are from normalized rips (which I doubt, the coincidence values are too high) but I'm still getting the same results.

Have anyone else make some check under the same conditions?
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greynol
post Jun 12 2012, 18:05
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So many of my original CDs are peak normalized, I really don't see how one can point the finger at AR or DAE software and cry foul.


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2Bdecided
post Jun 12 2012, 18:10
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QUOTE (greynol @ Jun 12 2012, 18:05) *
So many of my original CDs are peak normalized, I really don't see how one can point the finger at AR or DAE software and cry foul.
...and even if they're not quite 100% peak normalised, lots of software will only peak normalise the rip if the original peak is less than 98% (for example). That's -0.18dB FS. Lots of CDs are normalised to -0.1dB FS, so wouldn't be touched.


Hyouga, if you change the data, the AccurateRip CRC completely changes.

However, if you're looking at the AccurateRip values when ripping, these are calculated before any processing (normalising, scaling, lossy encoding!) for obvious reasons - so won't be affected by the normalisation. If you're checking the resulting files, these should be changed by the normalisation.

Sorry if this is all stating the obvious. Like you, I'm confused by what you're reporting.

Cheers,
David.

This post has been edited by 2Bdecided: Jun 12 2012, 18:12
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greynol
post Jun 12 2012, 18:20
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Regardless, AR was intended for checking original factory-pressed CDs. If that is what you're doing then this paranoia is rendered moot. If this is about checking illegally distributed material, I can't say I have any sympathy.

Now if it turns out that people are inadvertently peak normalizing or doing any other irreversible processing on rips that are verified by AR and are under the impession that they have perfect copies, that's another matter entirely.


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Hyouga
post Jun 12 2012, 23:49
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QUOTE
However, if you're looking at the AccurateRip values when ripping, these are calculated before any processing (normalising, scaling, lossy encoding!) for obvious reasons - so won't be affected by the normalisation. If you're checking the resulting files, these should be changed by the normalisation.


I'm getting the "Accurately ripped" results both when ripping (and normalizing) and afterwards with CUETools.

Anyway I understand that it makes sense that AccurateRip send those results, as they are not thechnically bad rips.
My main constern was to find a way to spot normalized tracks. I'll keep searching


Thanks everyone for your answers.
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Porcus
post Jun 13 2012, 06:03
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QUOTE (Hyouga @ Jun 13 2012, 00:49) *
ripping (and normalizing)


Again, are you sure you 'normalize'? The recommended thing to do, is to write ReplayGain tags, and that will only alter metadata.


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Goratrix
post Jun 13 2012, 10:14
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QUOTE (Hyouga @ Jun 13 2012, 00:49) *
I'm getting the "Accurately ripped" results both when ripping (and normalizing) and afterwards with CUETools.


That is very hard to believe. Could you post an example of two CUETools verifying logs of the same CD, one ripped without normalizing and one ripped with?

This post has been edited by Goratrix: Jun 13 2012, 10:15
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Porcus
post Jun 13 2012, 10:33
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QUOTE (Goratrix @ Jun 13 2012, 11:14) *
That is very hard to believe.


If it were reported to happen consistently, yes. But it is perfectly possible for tracks that are peak-normalized in the mastering. Again the OP needs to be more specific.


QUOTE (Goratrix @ Jun 13 2012, 11:14) *
Could you post an example of two CUETools verifying logs of the same CD, one ripped without normalizing and one ripped with?


That is certainly a good idea.

This post has been edited by Porcus: Jun 13 2012, 10:34


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