[BenAdamson]

Hey, I would like to test that my FLAC music collection obtained from various sources is actually all lossless FLAC files, converted directly from WAVs. Do you know of the best program to confirm that none of my files are 'fake lossless' - that is, converted from lossy mp3s etc.
 
Cheers!

 

[Dreaming Of A Better ...]

...

 

[BenAdamson]

Yeah, the problem is that some of the files are from friends, and some of those are pretty rare, which I'm unsure if a high-quality download or CD even exist of.

 

[J.Pocalypse]

I'd say, play the unsure flac files in foobar2000 and look at the bottom info bar. If the KHz aren't hovering around 44, then they're fakes. I have not tested this idea myself. It's just a theory that makes perfect sense to me.

 

[BenAdamson]

All of the files I tested with F2K were displaying as 44.1kHz precisely the whole song. This is fine, but what I have noticed is that nearly all of my mp3 files are also precisely 44.1kHz the whole way through. This doesn't seem to be a very good test! Surely it's just whatever sampling rate it was released at..?

 

[Roseval]

[size=10pt]If you see 44.1 all of the time, obvious Foobar is displaying the sample rate of the output file.[/size]
[size=10pt]What you need is the bitate of the audio file read.[/size]
[size=10pt]http://thewelltemperedcomputer.com/KB/BitRate.htm[/size]
 
[size=10pt]However this won’t help you.[/size]
[size=10pt]A simple example, take a 128 kbs MP3, convert it to WAV and you will have an audio file with 1411 kbs, the bitrate of a uncompressed format.[/size]
[size=10pt]This is what more or less happens when you play an MP3, it is expanded to raw PCM (16/44.1) otherwise the sound card don’t understand but of course expanding it back to this format won’t restore what has been lost in the compression.[/size]
 
[size=10pt]There are programs like AuCDTect.[/size]
[size=10pt]It can detect obvious artifacts like high roll of but I do think it only works reliable with low bit rate MP3.[/size]
[size=10pt]In essence this program is like us, having as much difficulties distinguishing between CD quality and high bitrate MP3.[/size]
[size=10pt]http://thewelltemperedcomputer.com/SW/Miscellaneous.htm[/size]
 

 

[th0m]

Quote:

I'd say, play the unsure flac files in foobar2000 and look at the bottom info bar. If the KHz aren't hovering around 44, then they're fakes. I have not tested this idea myself. It's just a theory that makes perfect sense to me.

 
That has nothing to do with the file being transcoded or not.
 
Detecting transcodes efficiently are actually quite tricky, but one way is to do a spectral analysis through Audacity, Audition or SoX and look for certain signs. There are guides for doing this if you google for it.
Looking for blocking and cut-off frequencies is one method: http://whatimg.com/images/54854744949039584031.gif

 

[BenAdamson]

Quote:

Originally Posted by Roseval /img/forum/go_quote.gif
 
There are programs like AuCDTect.
[size=10pt]It can detect obvious artifacts like high roll of but I do think it only works reliable with low bit rate MP3.[/size]
[size=10pt]In essence this program is like us, having as much difficulties distinguishing between CD quality and high bitrate MP3.[/size]
[size=10pt]http://thewelltemperedcomputer.com/SW/Miscellaneous.htm[/size]

Would you recommend AuCDTect? It seems like it was designed with exactly this use in mind.


Quote:

 http://whatimg.com/images/54854744949039584031.gif

That link is broken.
 

 

[th0m]

Quote:

That link is broken.

Try this one: http://i302.photobucket.com/albums/nn108/nissepelle/54854744949039584031.gif
 

 

[BenAdamson]

Quote:

Try this one: http://i302.photobucket.com/albums/nn108/nissepelle/54854744949039584031.gif
 

That is a very interesting image, clearly demonstrating the effect! I'll see if I can find anything with my music.
 
 

 

[gyrodec]

Ben
 
The good news is that there is such a program. It reads file information and can tell with 95% + accuracy if the FLAC came from a WAV/CD or MP3. It dets details from the header parts of the fiel, it doesn't analyze the audio stream.
 
The bad new is I can't remember what it is, and in the 4 minutes I had free to Google it for you, I couldn't find it. I also couldn't find it on my music PC at the moment.
 
If you can find the right key words, you will find it. "FLAC MP3 media information" doesn't find it.

 

[kevin8432]

Have you tried "Spectro"? It works for mp3 and flac.

 

[xnor]

This question keeps getting asked over and over again...... use the search.

 

[Assimilator702]

Quote:

don't know about a tester program, but i know one 100% foolproof way to get a real FLAC rip, buy the CD.
 
you'll have to wait a bit more for a useful reply.

That was THE WORST reply I've ever had the displeasure of reading on ANY FORUM  on ANY SUBJECT in the last 10 years.

 

 

[Assimilator702]

Quote:

Ben
 
The good news is that there is such a program. It reads file information and can tell with 95% + accuracy if the FLAC came from a WAV/CD or MP3. It dets details from the header parts of the fiel, it doesn't analyze the audio stream.
 
The bad new is I can't remember what it is, and in the 4 minutes I had free to Google it for you, I couldn't find it. I also couldn't find it on my music PC at the moment.
 
If you can find the right key words, you will find it. "FLAC MP3 media information" doesn't find it.

I use Flac Tester and Audio Checker.
 
Both work very well.