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is it possible to detect mp3 sourced CDs?
sony666
post Oct 14 2003, 06:28
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QUOTE (LordSyl @ Dec 14 2002, 02:51 PM)
The frequency analysis is also an accurate way of telling if a CD is mp3 sourced: any original disc always reaches fully 22050Hz without cutting the 20+Khz area.

That's absolutely not true, I have a couple of original CDs from the early 80's that are lowpassed at 18KHz, for example (Dio - Holy Diver and The Last in Line)

Nevertheless, on most mp3 based files you might note a clear line at 16KHz, and not a lot of content above it.

This post has been edited by sony666: Oct 14 2003, 06:30
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Jojo
post Oct 14 2003, 13:02
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QUOTE (sony666 @ Oct 13 2003, 09:28 PM)
Nevertheless, on most mp3 based files you might note a clear line at 16KHz, and not a lot of content above it.

This is not exactly true, though. I have original CD's that have no frequencies higher than 16 kHz…for instance, some songs of the "Bloodhound Gang", but also newer peaces!


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MuMart
post Oct 14 2003, 14:33
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A good realtime spectrascope is an easy way to tell (baudline is good on linux,
there are probably plenty of winamp vis plugins for this).

MP3 has a very "steppy" frequency response due to freq-domain quantization,
and it is very easy to tell visually when PCM has been through an mp3 encoder.

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Martin
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Cyaneyes
post Oct 15 2003, 06:20
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Another thing to consider: if a show was recorded with a DAT at 32khz, the frequencies will cut off at 16. So a cut at 16khz isn't always a 100% reliable clue.
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cd-rw.org
post Feb 9 2005, 07:34
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Sorry to bounce an ancient thread, but...

Is just my imagination, or was the some time ago (perhaps a year or so?) a software introduced on this site which was used to analyze audio/cd content and "guess" if the audio has been lossly compressed at some point of production?

I have this feeling that I saw this kind of program some time ago, but I am now unable to find it. The search terms just don't cut it:" mp3, lossy, compression, etc.".

Anyone recall this one? I want to wipe clean my CD-R collection of lossy stuff.


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M
post Feb 9 2005, 07:54
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QUOTE (cd-rw.org @ Feb 9 2005, 01:34 AM)
Sorry to bounce an ancient thread, but...

Is just my imagination, or was the some time ago (perhaps a year or so?) a software introduced on this site which was used to analyze audio/cd content and "guess" if the audio has been lossly compressed at some point of production?

I have this feeling that I saw this kind of program some time ago, but I am now unable to find it. The search terms just don't cut it:" mp3, lossy, compression, etc.".

Anyone recall this one? I want to wipe clean my CD-R collection of lossy stuff.
*

Sure. It's auCDtect (command line, freeware)/Tau Analyzer (shareware, GUI-based).

- M.

This post has been edited by M: Feb 9 2005, 07:55
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esa372
post Feb 9 2005, 17:50
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QUOTE (M @ Feb 8 2005, 10:54 PM)
QUOTE (cd-rw.org @ Feb 9 2005, 01:34 AM)
I want to wipe clean my CD-R collection of lossy stuff.
Sure. It's auCDtect (command line, freeware)/Tau Analyzer (shareware, GUI-based).
auCDtect seems to be a great program, but (just so you know) I found three factory-pressed CDs that auCDtect reported as possibly being MPEG. So be careful; it's not 100% accurate.

Here's the link to my findings:
http://www.hydrogenaudio.org/forums/index....ndpost&p=269169


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