... detect fake 320kbps MP3s

[Geert]

Hi,

I own a quite huge MP3 library. And I'm a freak if it comes to the quality of that library.
The quality of the tags, the covers and of course the sound itself.

Not so long ago I detected the "CovArt Ops" program and was able to detect quite some poor quality cover art and replaced it.

At last (but not least), I'm looking for a program that is able to detect poor audio quality.
These days lots of crappy audio is posted on the internet.
People download a webrip of 128kbps, re-encode it as 320kbps and post it again and hope it will be downloaded a lot.
If, on that kind of stuff, you use all kind of programs that detect and tell you the bitrate, you'll get 320kbps.
But we all know better.

Here's a screenshot of the frequency spectrum of a certain track of 320kbps (CBR) as produced by "Adobe Audition":

http://i53.tinypic.com/2wbxm69.png

And here's another screenshot of the frequency spectrum of exactly the same track in a "220kbps (VBR)" version:

http://i54.tinypic.com/24x12ye.png

When you compare the two, you are immediately able to unmask the first one as being a fake 320kbps version.
When I would have used a program to deduplicate my library, it would simply look at the bitrate and come back and tell me to keep the first and delete the second.
While the opposite is the right thing to do.

But of course, it's impossible to open each and every song of my library in Adobe Audition and look at it's quality.
Hence, who knows of a program that can (frequency)analyze my complete music library and tell me where the bad quality songs are located (whatever their disguising bitrate is)?

Thanks

[Anupam]

I have removed the mention of a commercial software, because it was unnecessary.

I have also replaced the images as links, because the size of the images was making the post go crazy.

I don't know about comparing spectrum of mp3 at all, but I am saying this from what I see, and from logic.

You are showing spectrum of a 320 kpbs mp3 CBR, and 220 kbps VBR. Already there is a difference in kbps, plus, CBR and VBR are different things, and work differently. I feel that their spectrum will of course differ.

If you should compare, then I feel that an original mp3 encoded at 320 kbps CBR, should be compared to a "fake" 320 kbps CBR, which has been converted from 128 kbps.

Someone please correct me, if I am wrong here... I am just saying this from logic.

[Anupam]

Don't know if this will help you, but here is a freeware program to find out quality of mp3 file based on spectrum. An article was posted by our editor arto65.

http://www.techsupportalert.com/How-...-an-audio-file

[Geert]

You are showing spectrum of a 320 kpbs mp3 CBR, and 220 kbps VBR. Already there is a difference in kbps, plus, CBR and VBR are different things, and work differently. I feel that their spectrum will of course differ.

If you should compare, then I feel that an original mp3 encoded at 320 kbps CBR, should be compared to a "fake" 320 kbps CBR, which has been converted from 128 kbps.

Correct, but to illustrate my point that doesn't really matter, imo.
Maybe I should have explained in more detail why I concluded

"When you compare the two, you are immediately able to unmask the first one as being a fake 320kbps version."

You clearly see in the first screenshot that all frequencies above 16000Hz have been removed while from the second screenshot you can derive that the track originally did contain them. (although it's a a "220kbps (VBR)" version)
So that first track can impossibly be a real 320kbps version.

Concerning the freeware "Spek" in the article of arto65: thanks for drawing my attention to that.
But unfortunately, it provides the same information as "Adobe Audition" and I have to feed the program each of my mp3 files manually.
I'm looking for a program that I point to my music directory and that - after some processing time - tells me what songs are missing the frequencies above eg. 16000Hz.