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HELP! Lossy or Lossless?

I have there a concert and I think its mp3 sourced, but im not sure. The file format is flac. Here is a picture of a spectral view of the file:


Could anybody tell me if this is the lossless version or a lossy mp3 sourced file?
Thx in advance!

HELP! Lossy or Lossless?

Reply #1
Well how large is the file? FLAC is considerably larger byte-wise.

HELP! Lossy or Lossless?

Reply #2
Adamn is talking about the source, not about the current format (flac, apparently). A lossless encoding of a lossy source is still very big.

There's a clear 16 KHz lowpass: it looks like a lossy encoding.

HELP! Lossy or Lossless?

Reply #3
Did you try Tau Analyser yet? You will need to burn an audio CD of the FLAC first...
Over thinking, over analyzing separates the body from the mind.

HELP! Lossy or Lossless?

Reply #4
Quote
Did you try Tau Analyser yet? You will need to burn an audio CD of the FLAC first...
[a href="index.php?act=findpost&pid=266251"][{POST_SNAPBACK}][/a]

Hi everybody!
Thx for all of your help.
No, i dont need to burn a audio CD first, there is another version of Tau Analyser, without GUI.
Tau Analyser says:
"This track looks like MPEG with probability 95%"

So does this mean its from a lossy source?

HELP! Lossy or Lossless?

Reply #5
Quote
So does this mean its from a lossy source?


Very likely, yes.

HELP! Lossy or Lossless?

Reply #6
I bet it has been mp3 (or some other lossy codec). The hard cutoff at 16kHz is typical.
Did you try auCDtect ? It can analyse wav files to see if they have been a lossy codec.

edit: I've just seen that Tau Analyser is based on the same algorithm like auCdtect, but isn't free.
I know that I know nothing. But how can I then know that ?

HELP! Lossy or Lossless?

Reply #7
If it's a live bootleg sort of thing, it could have been recorded by some dude with a digital recorder going directly to MP3 format or something. Later he converted it to FLAC since that's what all the bootleg trading is done in. Stupid? Yep.

HELP! Lossy or Lossless?

Reply #8
Quote
If it's a live bootleg sort of thing, it could have been recorded by some dude with a digital recorder going directly to MP3 format or something. Later he converted it to FLAC since that's what all the bootleg trading is done in. Stupid? Yep.
[a href="index.php?act=findpost&pid=266322"][{POST_SNAPBACK}][/a]

Is it possible, that a Minidisc recording of a show could look like mp3 sourced? Im using a Sony MD MZ-N10, LP2 mode ... this doesnt look like a lossy format. Never tried the LP4 mode.

HELP! Lossy or Lossless?

Reply #9
My Hauppage PVR 250 has a hard cutoff at around 16khz as well. Looks like MP3 in spectral view. Most likely though, your audio was mp3 sourced.

I have several "silver" cd's from Europe & Russia that are mp3 sourced. Some of the lossless stuff in trading circles was also mp3 sourced. Fortunately, it's a small amount.
flac>fb2k>kernel streaming>audiophile 2496>magni>dt990 pro

HELP! Lossy or Lossless?

Reply #10
As has been said, it's definitly possible that it's lossy sourced...BUT... It could also have also been recorded live at 32kHz.
"You can fight without ever winning, but never win without a fight."  Neil Peart  'Resist'

HELP! Lossy or Lossless?

Reply #11
iRiver IFP series flash recorders have a hard-cutoff at 16kHz as well, even at 320kbps. I noticed the same spectral profile as posted above when I was "ripping" some LP's direct to MP3.

HELP! Lossy or Lossless?

Reply #12
Quote
As has been said, it's definitly possible that it's lossy sourced...BUT... It could also have also been recorded live at 32kHz.
[a href="index.php?act=findpost&pid=266479"][{POST_SNAPBACK}][/a]


Although it's hard to judge by eyeballing it, I'd probably say that it is not a 32kHz recording. It appears that there is content to 16.5kHz in the graph; when recording at 32kHz, most encoders will roll off a little bit before 16kHz. But, I could be wrong.

HELP! Lossy or Lossless?

Reply #13
Quote
Is it possible, that a Minidisc recording of a show could look like mp3 sourced? Im using a Sony MD MZ-N10, LP2 mode ... this doesnt look like a lossy format. Never tried the LP4 mode.
[a href="index.php?act=findpost&pid=266432"][{POST_SNAPBACK}][/a]

Ah, that's a question for me.
I bet: No! (SP)
I own two hifi-MD recorders; both don't cause a hard cutoff at ~16kHz. MD-ATRAC is the only lossy format I've encountered so far which has this aspect. It is detected by auCDtect as being "lossy", though.
Please don't use LP modes, the quality is much worse there. The bitrate is then only 292/2=146kbps (LP2), well below the general limit of audibility at roughly 200kbps I think.
Quote
My Hauppage PVR 250 has a hard cutoff at around 16khz as well. Looks like MP3 in spectral view. Most likely though, your audio was mp3 sourced.
[a href="index.php?act=findpost&pid=266454"][{POST_SNAPBACK}][/a]

Is this a standalone hifi MD-recorder ? Hauppauge...  ?

Quote
As has been said, it's definitly possible that it's lossy sourced...BUT... It could also have also been recorded live at 32kHz.
[a href="index.php?act=findpost&pid=266479"][{POST_SNAPBACK}][/a]

Good point.
Could you, Adamn, offer a detailed screenshot ? 32kHz sampling can't have any content above 16kHz audio frequency...

edit: mmm..."audibility limit" seems to be no English word...What would you say instead ? audibleness ? transparency level ?
I know that I know nothing. But how can I then know that ?

HELP! Lossy or Lossless?

Reply #14
Quote
Could you, Adamn, offer a detailed screenshot ? 32kHz sampling can't have any content above 16kHz audio frequency...

Here is a frequency analysis of that file, hope this helps:


And for comparison, this is a file, i recorded with my Sony MD MZ-N10 in LP2 mode:

To this file, auCDtect says: "This track looks like CDDA with probability 100%"

HELP! Lossy or Lossless?

Reply #15
Quote
To this file, auCDtect says: "This track looks like CDDA with probability 100%"

Uh, uh..
Which ATRAC-type and which year is your MD-recorder ? I can hardly believe that auCDtect fails so thoroughly...even worse, it's LP. How did you transfer the MD-record to hard disc ? In an analog way ? On the other hand, it's good for MD-ATRAC if auCDtect can't detect it.
What I meant by "detailed" is a zoom-in to the 16000-16500Hz area on your first frequency view screenshot.
I know that I know nothing. But how can I then know that ?

HELP! Lossy or Lossless?

Reply #16
Quote
Quote
To this file, auCDtect says: "This track looks like CDDA with probability 100%"

Uh, uh..
Which ATRAC-type and which year is your MD-recorder ? I can hardly believe that auCDtect fails so thoroughly...even worse, it's LP. How did you transfer the MD-record to hard disc ? In an analog way ? On the other hand, it's good for MD-ATRAC if auCDtect can't detect it.
What I meant by "detailed" is a zoom-in to the 16000-16500Hz area on your first frequency view screenshot.
[a href="index.php?act=findpost&pid=266836"][{POST_SNAPBACK}][/a]

Year of the MD-Recorder: 9/2002
ATRAC-Type: ATRAC DSP Type-S
I transfered the MD-record to harddisk by a MD-deck, no, not analog, digital!

Screenshot of that other file will follow later.

thx again for all of your help!

HELP! Lossy or Lossless?

Reply #17
I'm having a similar issue with auCDtect ; maybe you guys can help me suss it out.

I have MoFi UltraDisc and UltraDisc-II gold CDs of Dark Side Of The Moon.  Out of sheer boredom, I ran auCDtect on both sets of EAC-ripped WAV files and the results are less than reassuring...

Result for MoFi UD CD:
Code: [Select]
auCDtect: CD records authenticity detector, version 0.8.2
Copyright (c) 2004 Oleg Berngardt. All rights reserved.
Copyright (c) 2004 Alexander Djourik. All rights reserved.
------------------------------------------------------------
Processing file:        [01 Speak To Me.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 86%

------------------------------------------------------------
Processing file:        [02 Breathe.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 89%

------------------------------------------------------------
Processing file:        [03 On The Run.wav]
Data analysis:          [100%]
------------------------------------------------------------
Could not qualify the source of this track.

------------------------------------------------------------
Processing file:        [04 Time.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 42%

------------------------------------------------------------
Processing file:        [05 The Great Gig In The Sky.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 100%

------------------------------------------------------------
Processing file:        [06 Money.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 99%

------------------------------------------------------------
Processing file:        [07 Us And Them.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 85%

------------------------------------------------------------
Processing file:        [08 Any Colour You Like.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 49%

------------------------------------------------------------
Processing file:        [09 Brain Damage.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 92%

------------------------------------------------------------
Processing file:        [10 Eclipse.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 100%

Why are the results so varied?
Check out tracks 5 & 6: CDDA @ 100% probability and MPEG @ 99% probability.
 
And when I scan the entire album as a single WAV file, I get this:
Code: [Select]
Processing file:        [UD.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 79%


 

The analysis for the UltraDisc II is no better.
Result for MoFi UD-II CD:
Code: [Select]
auCDtect: CD records authenticity detector, version 0.8.2
Copyright (c) 2004 Oleg Berngardt. All rights reserved.
Copyright (c) 2004 Alexander Djourik. All rights reserved.
------------------------------------------------------------
Processing file:        [01 Speak To Me.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 94%

------------------------------------------------------------
Processing file:        [02 Breathe.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 92%

------------------------------------------------------------
Processing file:        [03 On The Run.wav]
Data analysis:          [100%]
------------------------------------------------------------
Could not qualify the source of this track.

------------------------------------------------------------
Processing file:        [04 Time.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 49%

------------------------------------------------------------
Processing file:        [05 The Great Gig In The Sky.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 62%

------------------------------------------------------------
Processing file:        [06 Money.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 100%

------------------------------------------------------------
Processing file:        [07 Us And Them.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 89%

------------------------------------------------------------
Processing file:        [08 Any Colour You Like.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 92%

------------------------------------------------------------
Processing file:        [09 Brain Damage.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 73%

------------------------------------------------------------
Processing file:        [10 Eclipse.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 100%
Well, at least track 10 is consistent... 
But check out track 6 (UD-II): MPEG @ 100% probability?!  100% ?!?

And scanning the whole UD-II album as a WAV gives the same result as the UD WAV:
Code: [Select]
Processing file:        [UD-II.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 79%

So, I'm going to start testing a variety of different CDs, because these results definitely throw the accuracy of auCDtect into question.

But if any of you audio brahmins have any insight as to why this happens, please let me know.

Thanks in advance,

~esa
Clowns love haircuts; so should Lee Marvin's valet.

HELP! Lossy or Lossless?

Reply #18
OK, I found another one: The MoFi UltraDisc-II gold CD of Steely Dan's Aja.
 
Code: [Select]
auCDtect: CD records authenticity detector, version 0.8.2
Copyright (c) 2004 Oleg Berngardt. All rights reserved.
Copyright (c) 2004 Alexander Djourik. All rights reserved.
------------------------------------------------------------
Processing file:        [01 Black Cow.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 95%

------------------------------------------------------------
Processing file:        [02 Aja.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 99%

------------------------------------------------------------
Processing file:        [03 Deacon Blues.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 49%

------------------------------------------------------------
Processing file:        [04 Peg.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 43%

------------------------------------------------------------
Processing file:        [05 Home At Last.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 99%

------------------------------------------------------------
Processing file:        [06 I Got The News.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like CDDA with probability 76%

------------------------------------------------------------
Processing file:        [07 Josie.wav]
Data analysis:          [100%]
------------------------------------------------------------
This track looks like MPEG with probability 89%
Could it have something to do with the years these CDs were produced?
The MoFi CDs of Dark Side were issued in 1988 and Aja was issued in 1990.  I haven't found this problem on any of the later UltraDiscs I have (1990-1999)... 
Clowns love haircuts; so should Lee Marvin's valet.

HELP! Lossy or Lossless?

Reply #19
Could it be that auCDtect expects a special (newish, 90s-) style of mastering (sensible, since lossy codecs didn't exist before)? Special frequency content, which its calculations are based on ?
Are the recordings actually from 1988/90, or were they rereleased/remixed/remastered at that time ?
Frequency content has slowly changed since the 70s...
I assume this CDs are all CD-DA and auCDtect fails.
I know that I know nothing. But how can I then know that ?

HELP! Lossy or Lossless?

Reply #20
Thanks for the reply, precisionist...

Quote
Are the recordings actually from 1988/90, or were they rereleased/remixed/remastered at that time ?
The recordings are from 1973 and 1977 and MoFi uses the original mater tapes for their gold CDs, but AFAIK they do not alter the recordings in any way (for example, no remastering or remixing - just an exact copy of the master tape.)

Quote
Could it be that auCDtect expects a special (newish, 90s-) style of mastering (sensible, since lossy codecs didn't exist before)? Special frequency content, which its calculations are based on ?
[...]
Frequency content has slowly changed since the 70s...
No doubt, but could that be the reason auCDtect has such trouble with these CDs?

Quote
I assume this CDs are all CD-DA and auCDtect fails.
Correct.  Factory pressed; retail package.
Clowns love haircuts; so should Lee Marvin's valet.

HELP! Lossy or Lossless?

Reply #21
Quote
No doubt, but could that be the reason auCDtect has such trouble with these CDs?

I guess I'll analyze some old records with auCDtect...
Quote
Quote
I assume this CDs are all CD-DA and auCDtect fails.
Correct.  Factory pressed; retail package.
[a href="index.php?act=findpost&pid=269681"][{POST_SNAPBACK}][/a]

Actually I meant that at first the source of a CD's audio is not yet determined, whatever way one has got the CD. Lossy artefacts on factory pressed CDs bought in a 'normal' way (hifi-store...) are very unusual, thus the CDs should be real CD-DA; mastering engineers don't deal with data compression. Therefore auCDtect obviously fails.
I know that I know nothing. But how can I then know that ?

HELP! Lossy or Lossless?

Reply #22
Quote
I guess I'll analyze some old records with auCDtect...
Please let me know what you find out... 


Quote
Actually I meant that at first the source of a CD's audio is not yet determined, whatever way one has got the CD. Lossy artefacts on factory pressed CDs bought in a 'normal' way (hifi-store...) are very unusual, thus the CDs should be real CD-DA; mastering engineers don't deal with data compression. Therefore auCDtect obviously fails.
Agreed.


And earlier, I said:
Quote
The MoFi CDs of Dark Side were issued in 1988...
...but I have a correction.  I just found out that, while the UltraDisc of Dark Side was in fact issued in 1988, the UltraDisc-II was issued in 1993.

I was checking my discs against the description found here to verify authenticity, and they list the UD-II as being issued in 1993.

Thanks for your help, precisionist.
I hope we can get to the bottom of this; I don't like the idea of auCDtect giving false results all this time...
Clowns love haircuts; so should Lee Marvin's valet.

HELP! Lossy or Lossless?

Reply #23
Something even stranger IMO.

So I have that mp3 file:



I decoded it with foobar2000 to WAV (PCM, fixed-point), once with Dither and once without Dither. And here's what auCDtect reveals:



Can someone explain?

HELP! Lossy or Lossless?

Reply #24
Quote
So I have that mp3 file:
...
Can someone explain?
[{POST_SNAPBACK}][/a]
Certainly. Dither changes the frequency of the quantization noise - this change in the frequency distribution of the file probably fools auCDetect's MPEG detection algorithm. The graphs [a href="http://recpit.prosoundweb.com/viewtopic.php?t=1284]Here[/url] (from the HA FAQ) should clear things up.

 
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