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Trick to Spot fake 320kbps Mp3 file

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kaushik

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got some mp3 tracks.played with CD player...they are showing 320kbps sample..but your ears does not agree

well they are probably fake...high bit rate MP3...so what to do to spot the nut!

well,

i use use cool edit pro. It visually displays how strong the frequency is. For a legitimate 320 file it should show that it cuts off no less than 18k. Most 128-192 bit files you find off the internet cut off around 16k or lower. If I check a 256-320 file which has a reading at 16k or lower then I know its a misrepresentation or fraud. Some of these fake 320s may not actually be re-encodes. Some may just be encoded from cheap encoding software.

..any other tricks ?
 
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cmsajith

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Hi Kaushik,

I am also from Bangalore. From where can we get the mp3s encoded in 320kpbs? If its available through any shops, how can we identify it from the normal mp3s?

thanks
Sajith
 

Anil kumar

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Hi Kaushik, you can also check the bitrate from windows media player. MP3 is good to listen on a portable devices like ipod or MP3 players & not on audiophile setups.



 
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kaushik

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anil,


i know in properties we can see bitrate ... that may be fake .....

take say 96kbps Mp3 >use a mp3 encoder >encode to 320kbps

n we get a fake 320kbps mp3


the trick i posted ..to evaluate the content quality in mp3
Kaushik
 

kaushik

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Hi Kaushik,

I am also from Bangalore. From where can we get the mp3s encoded in 320kpbs? If its available through any shops, how can we identify it from the normal mp3s?

thanks
Sajith
i am not sure whr u get mp3 at 320kbps ..in Bangalore.
well there are illegal ways to get original CD replicas :Din bangalore ,
i dont want to include such info in this forum ,

legally
but in landmark/planetM etc they sell mp3s not sure about bit rate
or ,

you can buy downloads of hiQ mp3 at sites like buy.com
 

vj_box

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I use sound forge to rip my own mp3s from audio cds.You also have Acid pro for some advanced solutions,where you can mix and master your mp3s at higher bit rates.mp3s are fine for computer music,but when it comes to hearing in a HT speakers,i would always prefer the cd audio or the dvd audio.
And most of the mp3s u buy in the market are 128 kbps,rarely u find the 320s and as kaushik told most of em are fake encoded.
Vj
 

bandobast

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Even 320kbps MP3, quality depends on source and converter.

If file is converted from source in lower quality or first coverted to MIDI from CD then WAV from MIDI then MP# from WAV then not, I mean not directly from CD, then naturally sound will become poor even you encorded it at 320kbps.

So don't rely on free MP3 file and blame others.

You must encord MP3 directly from CD yourself, if you want to have good quality.

Though you might know it already but I just paste link.

This encorder enables you to make MP3 directly from CD.

CDex | Open Source Digital Audio CD Extractor with more than 32,000,000 downloads
 

ajinkya

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i use use cool edit pro. It visually displays how strong the frequency is. For a legitimate 320 file it should show that it cuts off no less than 18k. Most 128-192 bit files you find off the internet cut off around 16k or lower. If I check a 256-320 file which has a reading at 16k or lower then I know its a misrepresentation or fraud.
Kaushik,
Why should the higher end frequency be an indicator of bitrate? Isn't the frequency an indicator of what is present in the music? Let us say I have a genuine 320kbps mp3 which contains only, say organ music with low freq. content that does not go above 10K. Then your software will show cutoff below 18K which is fine because the music contains only 10K upper frequencies. The mp3 is still genuine and is encoded at 320Kbps. How does one get around this problem? Unless I misunderstand what frequency is being represented by the cooledit s/w.
 

mister_moonlight

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Using spectral analysis (Audacity is my program of choice, and its multi platform) one can usually see a cut off at 16Khz as the signature of a 128kbps mp3 source and 21Khz as the signature of Lossless.

One problem in using this "cut off" level method is that the same cut off which characterises lossy encodes may also be the result of a poor quality recording - a bootleg of a live show or a bad 'third world' vinyl master.


What has not been discussed is the 'blocky' appearance of the spectral analysis of lossy rips which is noticeable only when you zoom in close enough. IMHO this is a more reliable way to detect whether a file which purports to be lossless has in fact been transcoded from a lossy rip, and may even be a useful way to detect re-encodes from lower to higher bitrate mp3s (although this is much harder whatever method you use).

The image below illustrates what I mean. The track (from an album by Philip Glass) was ripped from CD to flac and a 1 second sample was saved to 320 kbps LAME mp3 and 128 kbps FhG mp3 and then in each case saved again to flac. The spectral analysis was done at full screen on a monitor with resolution of 1280 x 1024. Each of the three strips below is of the same 0.15 of a second.

FLAC / 320 mp3 / 128 mp3 compared



And here are bigger strips of the three spectral analyses. The zoom level is the same - bigger simply means that what is shown here is around 0.5 of a second - and NOT the whole track!

FLAC


320Kbps LAME mp3


128Kbps FhG mp3




thanks to the users at w********.fm for the material used to construct this guide.

peace.
 

Stuge

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in b/w size of the file also gives you idea whether it is 320kpbs or not .

correlate it with the total play back time of the song with the size of the file .

Well ,secondly as said by the first poster if you listen a lot and not a noob at all, you can find out just by listening .
 
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ajinkya

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I'm still not clear what frequencies the spectral analysis is plotting. If they are the frequencies contained in the music content, then my earlier question still remains...what about music content that does not have any high freq. or harmonics?
 

kaushik

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Kaushik,
Why should the higher end frequency be an indicator of bitrate? Isn't the frequency an indicator of what is present in the music? Let us say I have a genuine 320kbps mp3 which contains only, say organ music with low freq. content that does not go above 10K. Then your software will show cutoff below 18K which is fine because the music contains only 10K upper frequencies. The mp3 is still genuine and is encoded at 320Kbps. How does one get around this problem? Unless I misunderstand what frequency is being represented by the cooledit s/w.
yes u r correct....actually my technique is suitable 4 files with mixture of freq/instruments,u have to know that there are instruments that r beyond 13k or so... else for files having only mid freq, some other technique is needed....

some one told size is an indicator...but re-encoding may be used to increase size,also i agree CD encoder is one key factor that effects quality....


in case u do ur own cd >mp3..
recommended rippers are :Accurate rip,EAC.
 

mister_moonlight

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Kaushik,
Why should the higher end frequency be an indicator of bitrate? Isn't the frequency an indicator of what is present in the music? Let us say I have a genuine 320kbps mp3 which contains only, say organ music with low freq. content that does not go above 10K. Then your software will show cutoff below 18K which is fine because the music contains only 10K upper frequencies. The mp3 is still genuine and is encoded at 320Kbps. How does one get around this problem? Unless I misunderstand what frequency is being represented by the cooledit s/w.
I'm still not clear what frequencies the spectral analysis is plotting. If they are the frequencies contained in the music content, then my earlier question still remains...what about music content that does not have any high freq. or harmonics?
you are correct in saying that spectral analysis alone will not be enough to determine bitrate if higher frequencies are simply not present.

however, noting the characteristic of the spectral analysis of 320 vs 128, it can clearly be noted that there is 'blocks' present, much more clearly in 128 as opposed to 320. In the flac it can be noted that there is no blocking present. Hence even if a 128 file is transcoded to 320, bocks will be present in the spectral analysis.

Also, since we are only looking for the telltale sign of blocks, the absence of higher level frequencies, >13k, is pretty much a non issue as this effect is present throughout the frequency spectrum.

It is virtually impossible to tell the actual bitrate of a track, but using kaushiks method and what i have suggested might make it a little easier to narrow it down.

hope this helps

peace



edit: i will try and find some track with only low-ish frequency presence(<13k) and demonstrate the method i had mentioned. any suggestions?
 
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ajinkya

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Thanks to both. That clears up the slight doubt in my mind. For a bass heavy track, Bassotronics' "Base, I Love you" might be one with low freq. But it has some electronica so don't know what the higher cut-off is.
 
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