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Topic: True or fake high quality music ? (Read 29326 times) previous topic - next topic
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True or fake high quality music ?

Dear all,
I got some troubles with flac file  , coz I do not know it's really real or fake.(It took me a long time to download, so I do not want to be a victim of cheating  ). So I use Audio Checker and Spectro. They infact showed two different results, Audio Checker was 99% CDDA, but Spectro was 60% original.
Here it is :





True or fake high quality music ?

Reply #1
I dont want to spam, but I think here is a more clearly example : The Audio Checker gave the result 100% but the spectrum given by Spectro looks like mp3's one  , the bit rate is 1,441 kbps 




True or fake high quality music ?

Reply #2
Such questions come up occasionally on HA.. The short answer is that you can't know for sure whether something is a "genuine" FLAC or a transcode, those programs are merely (good) guessers.
Probably the best thing you can do is compare the files to those from another (trusted) source.

Also, you're misinterpreting the info from that spectrum analyzer. 60% size means 60% of the WAV. And the bitrate of FLAC and WAV will of course be different, that's the whole point of compression.

True or fake high quality music ?

Reply #3
With Spectro you're just looking at frequency content in the two graphs. The 2nd screenshot is showing a recording without much high-frequency content, except for one little spike. Maybe the recording never had much treble content, or it did but has had noise reduction applied to it, or maybe it was taken from a radio broadcast. Or maybe it was subjected to lossy encoding at one point. I find Spectro to be useful for comparing two different lossy versions of the same recording, rather than spotting transcodes, although I've used it for that, too.

AudioChecker is a front end for AuCDtect (Google it). It performs statistical analysis of the frequency content, looking for suspicious patterns. The percentage it gives you is based on its own criteria and isn't really a percentage guarantee of anything. Try it on files you've created yourself, both lossless and lossy, and see what results it gives. I found that it wasn't all that reliable; the presence or absence of high-frequency content can really affect the numbers it gives.

If you're worried about the authenticity of music you get from questionable sources, there's an adage about gift horses that could be said to apply.

True or fake high quality music ?

Reply #4
The only way you can be absolutely sure that a FLAC is from a lossless source is if you do the encoding yourself.

Otherwise, that's what you get for going on warezzzzzzzz torrent sites and downloading that stuff illegally.


True or fake high quality music ?

Reply #5
The only way you can be absolutely sure that a FLAC is from a lossless source is if you do the encoding yourself.

Otherwise, that's what you get for going on warezzzzzzzz torrent sites and downloading that stuff illegally.

there are some sites that offer Flac download legally, such as bandcamp and Live Metallica.


True or fake high quality music ?

Reply #7
there are some sites that offer Flac download legally, such as bandcamp and Live Metallica.


True.  However, people that use "coz" and "plzzzzzz" in their posts rarely visit and BUY from legitimate FLAC download sites.

True or fake high quality music ?

Reply #8
Look at the line going across the ~16kHz mark especially near the end. Looks like the source was topped at 16kHz and higher frequencies were guessed and overlaid. ...Unless there is just background noise as if a CRT TV was in the background while the sound was recorded.
Mixing audio perfectly doesn't take more than onboard.

True or fake high quality music ?

Reply #9
I downloaded the Spectro and tested with FLAC files I have. All of them are straight from CDs I own, and none of them are over 70%, lol.

As others said, they are just good guessers.

True or fake high quality music ?

Reply #10
I downloaded the Spectro and tested with FLAC files I have. All of them are straight from CDs I own, and none of them are over 70%, lol.

*facepalm*

you're misinterpreting the info from that spectrum analyzer. 60% size means [the size of the FLAC is] 60% [of the size] of the WAV.


In other words, the percentage shown by Spectro has nothing to do with the percentage reported by AudioChecker. Spectro is just saying how big the file is, compared to the decompressed version. For example, if the FLAC is 7MB and the audio data you get out of it is 10MB, Spectro will say
Size: 7.00MB (70% of original)
Original Size: 10.00MB

It's not particularly useful info.

True or fake high quality music ?

Reply #11
Look at the line going across the ~16kHz mark especially near the end. Looks like the source was topped at 16kHz and higher frequencies were guessed and overlaid. ...Unless there is just background noise as if a CRT TV was in the background while the sound was recorded.
Presumably the latter; I fail to see why a lowpass followed by some kind of guessed reconstruction would create such a line.

True or fake high quality music ?

Reply #12
You know what, IMHO, you should buy that album in a original physical CD format and rip it on your own. That way, you won't have to go to sleepless nights thinking whether you downloaded a fake FLAC-encoded music. And also by doing that, you'll be more than a 100% sure it's genuine FLAC 
sin(α) = v sound/v object = Mach No.

True or fake high quality music ?

Reply #13
You know what, IMHO, you should buy that album in a original physical CD format and rip it on your own. That way, you won't have to go to sleepless nights thinking whether you downloaded a fake FLAC-encoded music. And also by doing that, you'll be more than a 100% sure it's genuine FLAC 


Not really. I've seen tracks that appeared to be MP3s on a legitimate album. These were some old live recordings added as a bonus and I guess that they didn't survive losslessly, but it shows that buying a CD is not a warranty of anything....though I have to add that I'm not 100% certain they were indeed MP3s. You never know.

True or fake high quality music ?

Reply #14
Not a guarantee, sure—and I’ve seen that too (and seen threads here about it)—but I would suppose that lossy-sourced tracks on CDs are relatively rare (perhaps very). Plus, music enthusiasts may well be interested in that; whereas none care if someone else’s pirated music is not authentic or about helping them to investigate that possibility! That’s a risk that comes with the territory.

True or fake high quality music ?

Reply #15
Very rare indeed.
sin(α) = v sound/v object = Mach No.

True or fake high quality music ?

Reply #16
Maybe this can help you in detecting what is "fake" lossless audio:
http://www.flickr.com/photos/60080664@N04/5485470134/

It's WAV file from an MP3 320kbps CBR source, and an original FLAC ripped from an original CD. Note that the fake WAV has a cut thoughout the track in 22kHz meaning it has retained the psychoacoustic tricks applied to its MP3 source. On the other hand, the original FLAC retains its full quality. This is probably the best example to know what is FAKE lossless file.
sin(α) = v sound/v object = Mach No.

True or fake high quality music ?

Reply #17
Maybe this can help you in detecting what is "fake" lossless audio:
http://www.flickr.com/photos/60080664@N04/5485470134/

It's WAV file from an MP3 320kbps CBR source, and an original FLAC ripped from an original CD. Note that the fake WAV has a cut thoughout the track in 22kHz meaning it has retained the psychoacoustic tricks applied to its MP3 source. On the other hand, the original FLAC retains its full quality. This is probably the best example to know what is FAKE lossless file.
Plenty of legitimate releases roll off the treble below 22kHz. Some even 20kHz. Not usually completely - the difference should be visible with close inspection.

Looking at this the other way round, I wonder how low a bitrate mp3 I could pass off as lossless, by adding fake hi-frequencies etc?

Cheers,
David.

True or fake high quality music ?

Reply #18
Looking at this the other way round, I wonder how low a bitrate mp3 I could pass off as lossless, by adding fake hi-frequencies etc?


The following spectrograph is from a processed 192kbps CBR MP3. I see no reason why I couldn't replicate this process with 128 or maybe even lower. If I were honestly trying hard to dupe someone, I'd fix the little bump at 16kHz, but meh, this works as proof-of-concept, and as concrete evidence why you should never trust a spectrogram to determine a transcode.



You cannot use spectrographic analysis to prove anything when it comes to lossy audio.

Not a guarantee, sure—and I’ve seen that too (and seen threads here about it)—but I would suppose that lossy-sourced tracks on CDs are relatively rare (perhaps very).
I bought a pressed, pirate CD sourced from MP3 off of eBay once. Orbital's Blue Album, FWIW. I got bit because there was an MP3 release that had certain tracks on it. I wanted the certain tracks, but the MP3 release was bogus. However, some enterprising soul over in Asia (I forget where) took that bogus release and pressed it. I mistook the eBay sale as a legit release and bought it. It was silver and silkscreened and everything! Not even a burn. The packaging had no catalog number info or anything.

True or fake high quality music ?

Reply #19
Looking at this the other way round, I wonder how low a bitrate mp3 I could pass off as lossless, by adding fake hi-frequencies etc?

Well, as you know, a good way to please the spectrograph types is to use an aggressive LossyWAV setting on an mp3, lossy on top of lossy which adds plenty of stuff to "re-fill" the spectrum. Perhaps a strap-line for lossyWAV - "half the filesize of lossless compression AND it makes your spectrograph look even better than the original". 

C.
PC = TAK + LossyWAV  ::  Portable = Opus (130)

True or fake high quality music ?

Reply #20
Hi,

If you want to be sure about the quality of FLAC, why don't take a WAV file (rip a track from a CD to a WAV), encode that WAV to FLAC, and then decode the FLAC back to WAV again.  Than do a bit-by-bit comparison of the 2 WAV files.  They should be the same.  FLAC is nothing but a compressor/decompressor like WinZip or something like that (except it's in the form of a codec).

If you download stuff (bittorrents etc...), you will never know what the source is, and you can not do a qualified judgement on it.

Regards,
Peter




True or fake high quality music ?

Reply #21
After my (several and probably embarrassing  ) failed attempts, what's the bottomline? Could we know if it is true or FAKE?
sin(α) = v sound/v object = Mach No.

True or fake high quality music ?

Reply #22
@thesurfingalien: That wasn't what he asked about. He wanted to know how you can tell if a lossless file had been encoded from a lossy file.

@SonicBoom!: The bottom line is that you can sometimes make a guess that has a fair chance of being right, but there is no sure-fire way to tell.

True or fake high quality music ?

Reply #23
@SonicBoom!: The bottom line is that you can sometimes make a guess that has a fair chance of being right, but there is no sure-fire way to tell.
...and it's far easier to be able to say "this is sourced from lossy audio" (when there are obvious clues), than it is to say "this has never been lossy-ly encoded" (because someone could have hidden all the clues, or it was such high quality lossy that there were few clues to start with).


True or fake high quality music ?

Reply #24
If you want to be sure about the quality of FLAC, why don't take a WAV file (rip a track from a CD to a WAV), encode that WAV to FLAC, and then decode the FLAC back to WAV again.  Than do a bit-by-bit comparison of the 2 WAV files.  They should be the same.  FLAC is nothing but a compressor/decompressor like WinZip or something like that (except it's in the form of a codec).

If you download stuff (bittorrents etc...), you will never know what the source is, and you can not do a qualified judgement on it.
I think we're being charitable, and assuming that at least some people are interested in finding whether a legitimate source (CD, legally downloaded FLAC, etc) is truly lossless. In a few instances, it's clear they're not.

If someone downloads a lossless file illegally, and it sounds fine and looks fine, but they're still worried it might be a lossy version and this impacts their enjoyment, then they've largely created their own torture. I wonder who is putting out not-really-lossless lossless files, so good quality that you can't hear the problem, with all the clues removed? And if you can't hear the problem....?! Also, if a tree falls down in a forest with no one there, does it really make a noise?

etc

Cheers,
David.

 
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