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Topic: Regular CDs with lossy compression (Read 43479 times) previous topic - next topic
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Regular CDs with lossy compression

Reply #26
How does this "ringing" effect sound?
It sounds like it's ringing.

Here are comments from people who have actually heard it(!)
http://ff123.net/ringing.html

and pictures...
http://ff123.net/ringing_graph.html

Cheers,
David.
Ok, thanks. Now I think I know what you mean. I always thought it would belong to what I call "flanging" - though I´ve never heard it that sharp and so high. I didn´t observe these effects with G.I. Joe so far... but then I listened with loudspeakers and not with my headphone. If an MP3 encoder was used, does Lame still produce these artifacts anyway?
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #27
I agree, this track is clearly compressed. Very very sad, in my opinion. This would be a no-go for me, especially if I'd have to pay 15 Euros for it.

Indeed, the track could originate from a 44.1- or 48-kHz MP3. Looking at .halverhahn's image upload and my Audition plot, I can see blocking with a length of around 1100 samples (i.e. roughly 2x576 or 2x576x(44.1/48)) and band-wise gating during the quiet passage around second 19 - 22. The borders of these bands are at around (as measured visually in Audition) 6.5ish, 8.0ish?, 9.6, 11.5, 13.8, and 16 kHz. Does anyone have the scale factor band borders for MP3? Do they coincide?

Actually, exporting to 192-kb CBR MP3 in Audition 1.x gives a spectrogram very similar to the upload.

Update: Found the scale factor band tables here. Sorry, couldn't wait

Code: [Select]
Tables.hs

tableScaleBandBoundLong 44100 = [  0,   4,   8,  12,  16,  20,  24,  30,
                                  36,  44,  52,  62,  74,  90, 110, 134,
                                 162, 196, 238, 288, 342, 418, 576]
tableScaleBandBoundLong 48000 = [  0,   4,   8,  12,  16,  20,  24,  30,
                                  36,  42,  50,  60,  72,  88, 106, 128,
                                 156, 190, 230, 276, 330, 384, 576]

If we take the 48000 table, we get:

24 kHz * 156 / 576 =  6.50 kHz
24 kHz * 190 / 576 =  7.92 kHz
24 kHz * 230 / 576 =  9.58 kHz
24 kHz * 276 / 576 = 11.50 kHz
24 kHz * 330 / 576 = 13.75 kHz
24 kHz * 384 / 576 = 16.00 kHz

Bingo! It's a 48-kHz MP3 decoded to 44.1-kHz. Probably 192 kbps. Ouch...

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #28
I agree, this track is clearly compressed. Very very sad, in my opinion. This would be a no-go for me, especially if I'd have to pay 15 Euros for it.

Indeed, the track could originate from a 44.1- or 48-kHz MP3. Looking at .halverhahn's image upload and my Audition plot, I can see blocking with a length of around 1100 samples (i.e. roughly 2x576 or 2x576x(44.1/48)) and band-wise gating during the quiet passage around second 19 - 22. The borders of these bands are at around (as measured visually in Audition) 6.5ish, 8.0ish?, 9.6, 11.5, 13.8, and 16 kHz. Does anyone have the scale factor band borders for MP3? Do they coincide?

Actually, exporting to 192-kb CBR MP3 in Audition 1.x gives a spectrogram very similar to the upload.

Update: Found the scale factor band tables here. Sorry, couldn't wait

Code: [Select]
Tables.hs

tableScaleBandBoundLong 44100 = [  0,   4,   8,  12,  16,  20,  24,  30,
                                  36,  44,  52,  62,  74,  90, 110, 134,
                                 162, 196, 238, 288, 342, 418, 576]
tableScaleBandBoundLong 48000 = [  0,   4,   8,  12,  16,  20,  24,  30,
                                  36,  42,  50,  60,  72,  88, 106, 128,
                                 156, 190, 230, 276, 330, 384, 576]

If we take the 48000 table, we get:

24 kHz * 156 / 576 =  6.50 kHz
24 kHz * 190 / 576 =  7.92 kHz
24 kHz * 230 / 576 =  9.58 kHz
24 kHz * 276 / 576 = 11.50 kHz
24 kHz * 330 / 576 = 13.75 kHz
24 kHz * 384 / 576 = 16.00 kHz

Bingo! It's a 48-kHz MP3 decoded to 44.1-kHz. Probably 192 kbps. Ouch...

Chris
Wow! That was really impressive work. You guys are great!! Then we know for sure it is MP3 - and I´m also quite sure that the codec used is the original one from the Fraunhofer Institute. Look at the scan I provided of the cover - ProTools was used and Digidesign offers an MP3-option for it. This option uses the Fraunhofer encoder. It´s only a guess and not really proof though...

But how stupid to decode a 48 kHz-file to 44.1. But when decoding happens like that, is there any sampling rate conversion involved or is it something different which converts the sample rates? Or does it mean that the music simply is too fast?

Oh, I forgot... I did some proper listening with my headphones. Besides some pumping and several distortions I´m pretty sure I´ve heard some artifacts which could be described as "gating". Does something like this exists with MP3? I did not hear some "ringing" so far - but then there´s a lot of synthesized parts in the music and the string sections of Alan Silvestri always sound like they are "ringing" or "grainy".

When I´m back at home I´ll provide some further samples.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #29
Thanks!  Well, I'm pretty sure they resampled to 44.1 kHz when decoding the 48-kHz MP3. Haven't heard the uncompressed version, but this one doesn't sound too fast to me.

Now that you know it's an MP3, you shouldn't trust your hearing any more  Assuming it's 192 kbps, it probably sounds just fine, and compression artifacts, if any, are probably only audible in direct comparison to the uncompressed version... which unfortunately we don't have. I don't hear any artifacts. But I agree with 2Bdecided, some people might find the sound dull due to the bandwidth limitation.

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #30
Now that you know it's an MP3, you shouldn't trust your hearing any more  Assuming it's 192 kbps, it probably sounds just fine, and compression artifacts, if any, are probably only audible in direct comparison to the uncompressed version... which unfortunately we don't have. I don't hear any artifacts. But I agree with 2Bdecided, some people might find the sound dull due to the bandwidth limitation.

Chris
That´s exactly the problem. How can someone know how the original sound was? No one (aside from the composer, producer and several other people) don´t know the original. So we can´t compare. And I don´t know that much about MP3 that I could safely assume about artifacts. I could some years ago when I started with computer audio but since then the codecs have developed and they are much better now.

At least that´s the case with LAME. I don´t know about the codec from Fraunhofer institute if that one is still developed besides adding capabilites like surround or else.

As I said, there is something which sounds like artifacts but I´m not so sure. It could be "ringing" but it also could be the for Alan Silvestri typical high frequency strings. When I´ll upload more sample I´ll also provide a sample from "Van Helsing", recorded in 2004 with similar dynamics and from the same team. Maybe one can draw conclusions from that.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #31
another visual representation:


 

Regular CDs with lossy compression

Reply #32
Varèse is notorious for being economical. 

"Economical"... so that's the expression for asking the full bundle of euros for compressed content. 

Regular CDs with lossy compression

Reply #33
Since when do we hear music with our eyes?  I listened to the clip and it didn't sound bad.  As for what you see in the lowpass--I've seen an album in the past with a similar cutoff from an original pressed cd, and it didn't sound any worse than if it had the info all the way to 22khz.  I think the engineers know what they're doing...and Varese is a good label.
foobar 0.9.6.8
FLAC -5
LAME 3.98 -V3

Regular CDs with lossy compression

Reply #34
Since when do we hear music with our eyes?  I listened to the clip and it didn't sound bad.  As for what you see in the lowpass--I've seen an album in the past with a similar cutoff from an original pressed cd, and it didn't sound any worse than if it had the info all the way to 22khz.  I think the engineers know what they're doing...and Varese is a good label.


Well I also doubt that I'd be able to notice any artefacts (I mostly can't ABX lame -V5 from the original) but thats not really the point. I'd still be very peeved if I bought a pressed CD that was mastered from 192kbps mp3's. You think the "engineers knew what they were doing" well I very much doubt it, this is almost certainly a stuff up. Regardless of whether problems are immediately audible or not this is still a bad situation. What about ripping this CD to mp3's, you're going to have to transcode lossy to lossy just to do that - it's just plain wrong! If I had a CD like that I could see myself using lossless compression for situations where I'd otherwise use lossy - just to avoid transcoding - and then to add insult I'd know that my 800kpbs lossless files were really only 192kbps mp3 quality. Personally I'd be very unhappy with that purchase.

Regular CDs with lossy compression

Reply #35
I've seen an album in the past with a similar cutoff from an original pressed cd, and it didn't sound any worse than if it had the info all the way to 22khz.

How do you know that? Do you have the version with 22-kHz bandwidth available?

A young colleague at work recently gave low grades to an item in a blind test, while the other participants didn't. When I asked him why, he said the item sounded dull compared to the original. Well, the test item had a 16-kHz lowpass applied to it. That was basically the only artifact. So, again, even if something sounds "not any worse" to you, it might actually sound worse to someone else.

I agree with uart, when I buy a CD, I expect the highest quality possible via that medium given the original recording. Nothing less.

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #36
I've seen an album in the past with a similar cutoff from an original pressed cd, and it didn't sound any worse than if it had the info all the way to 22khz.

How do you know that? Do you have the version with 22-kHz bandwidth available?



That was a goof on my part when I wrote that.    No of course I don't have anything else to compare it against.  What I'm saying is, the only reason I even knew there was a cut in the frequency is I ran a spectro on a track, and had I not done that, I would've been none the wiser about the cutoff.  Its not that LeAnn Rimes' early work cd sounds bad.  It could've been the recording equipment that had limits because these came before she made it big in 1995.

You're right though, you should be able to get the whole thing, and any modern equipment would not have blocking like you see.  I don't understand it either.
foobar 0.9.6.8
FLAC -5
LAME 3.98 -V3

Regular CDs with lossy compression

Reply #37
So, finally the promised additional excerpts. You can find them here.

I don´t know if you can hear the same things as me but I´m under the impression that the high violins (given the fact that they are on the left side (as it is custom with the standard orchestra)) seem to wander around sometimes. Would that be typical for MP3? Or is it more a sign of the Dolby Surround processor used for this recording? Then there is the percussion (not the synthesized percussion, the one from "real" instruments) which sounds strange (for the lack of a better word). In the excerpt "The JOEs mobilize 3" there is a strange warbling artifact which not necessarily has to be a compression artifact.

When the percussion kicks in on some parts the violins seem to lose their "air" and their brilliance.

I have to admit that some of these things could very well come from processing via some DSP used in the production and not necessarily from the compression. Without a reference this is very hard but I´m under the impression that the whole score sounds kind of bright, a bit thin (apart from the overpowering deep bass) without the air that normally comes with a bright sound.

For comparison I also offered an excerpt from "Van Helsing", released in 2004. The style is quite similar (even the tonality) with less synthesizers but the same overall frequency response.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #38
What software was the CD ripped to WAV?  Is the CD copy-protected?  If ever, please don't throw TOS #9 on me, but if the CD is copy-protected, and was ripped altogether, one may get a resulting rip with 16kHz lowpass even if the CD has tracks with full frequency spectrum.  The culprit: another set of compressed audio files hidden within the CD, which surfaces when one rips a particular CD, instead of the original uncompressed tracks, when ripped improperly.

Just my 2 cents worth though.

EDIT:  Just browsed the CD on Amazon, its playtime is beyond 70 minutes, so I guess there won't be enough space for a data part on the CD, and therefore, may not be copy-controlled.
"Listen to me...
Never take unsolicited advice..."

Regular CDs with lossy compression

Reply #39
What software was the CD ripped to WAV?  Is the CD copy-protected?  If ever, please don't throw TOS #9 on me, but if the CD is copy-protected, and was ripped altogether, one may get a resulting rip with 16kHz lowpass even if the CD has tracks with full frequency spectrum.  The culprit: another set of compressed audio files hidden within the CD, which surfaces when one rips a particular CD, instead of the original uncompressed tracks, when ripped improperly.


Thats not how a copy protected CD works.  If you try to rip one of those, either you get the actual PCM, or else it errors out.

Regular CDs with lossy compression

Reply #40
What software was the CD ripped to WAV?  Is the CD copy-protected?  If ever, please don't throw TOS #9 on me, but if the CD is copy-protected, and was ripped altogether, one may get a resulting rip with 16kHz lowpass even if the CD has tracks with full frequency spectrum.  The culprit: another set of compressed audio files hidden within the CD, which surfaces when one rips a particular CD, instead of the original uncompressed tracks, when ripped improperly.


Thats not how a copy protected CD works.  If you try to rip one of those, either you get the actual PCM, or else it errors out.
Exactly. No copy protection on the disc. Extracting was done with EAC.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #41
Cavaille, how many tracks on the Joe CD seem to be MP3 compressed? All of them?

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #42
Cavaille, how many tracks on the Joe CD seem to be MP3 compressed? All of them?

Chris
While some say, only half of the tracks are compressed I can say that the whole CD has a frequency cutoff at 16 kHz. There is a difference though that has nothing to do with the lossy compression: the first 9 tracks are mastered differently. They are dynamically compressed with brickwall filtering with 0.2 dB to 0 dbFS left. All 12 tracks coming after that leave 0.5 dB to 0 dBFS.

But the MP3 compression is applied to the whole CD. Why do you ask?

EDIT: Here is the frequency response for the whole CD:


I seem to be mistaken. The last tracks seem to be coming from a lossless source.

Indeed, starting with track 15 to the last track 21 everything is lossless with fully frequency content. From approximately 70 minutes of music this still makes 50 minutes of lossy compressed music. Thank you for the question because if you wouldn´t have asked it I would have continued to say that the whole CD is lossy.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #43
Maybe Patricia Sullivan Fourstar got so used to the sound of her iPod that she applied this on purpose as it sounds "just right" to her ears.  Kind of like Portishead did in the 90's, when they pressed their studio masters on vinyl first and then sold the needle drop on CD. Next thing will be producers re-recording music from little mobile phone speakers before releasing, because that's supposed to sound as kids are used it.

Regular CDs with lossy compression

Reply #44
I know of a vinyl release that's cut from mp3s because the producer lost the masters.

And some Aphex Twin CD releases are mastered from cassette tape.

Regular CDs with lossy compression

Reply #45
Kung Fu Records' CD reissue of Alkaline Trio's Maybe I'll Catch Fire shows clear signs of being MP3-sourced.

Regular CDs with lossy compression

Reply #46
Indeed, starting with track 15 to the last track 21 everything is lossless with fully frequency content. From approximately 70 minutes of music this still makes 50 minutes of lossy compressed music. Thank you for the question because if you wouldn´t have asked it I would have continued to say that the whole CD is lossy.

Thanks! Interesting. What is also interesting: In the "Mobilize" track excerpts you uploaded, I can see that every single brickwall-limited waveform peak extends to precisely -0.50 dB. This shows that the mastering house was using MP3s as their source for most of the tracks (i.e. lossy compression was there before the limiting). Now let's recap.

The audiophile community tells us that even a 192-kbps MP3 is far from being transparent (source). However, a supposedly acclaimed mastering engineer obviously did not get suspicious about the sound of her mastering product, partially made from MP3s in the range of 192 kbps. Now, either

- said mastering engineer did not have a choice (had to use MP3s for half of the tracks, which I seriously doubt), or
- said mastering engineer has (or at least had) no clue what a spectrogram is and what its benefits are, and does not have the ears to distinguish an MP3 from an uncompressed source, and therefore made a serious mistake (I'm pretty sure of that), or
- contrary to the beliefs of some (or most?) of the audiophile community, an MP3 can be transparent even if it is almost one hour long (I'm pretty sure of that as well)

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #47
Indeed, starting with track 15 to the last track 21 everything is lossless with fully frequency content. From approximately 70 minutes of music this still makes 50 minutes of lossy compressed music. Thank you for the question because if you wouldn´t have asked it I would have continued to say that the whole CD is lossy.

Thanks! Interesting. What is also interesting: In the "Mobilize" track excerpts you uploaded, I can see that every single brickwall-limited waveform peak extends to precisely -0.50 dB. This shows that the mastering house was using MP3s as their source for most of the tracks (i.e. lossy compression was there before the limiting). Now let's recap.

The audiophile community tells us that even a 192-kbps MP3 is far from being transparent (source). However, a supposedly acclaimed mastering engineer obviously did not get suspicious about the sound of her mastering product, partially made from MP3s in the range of 192 kbps. Now, either

- said mastering engineer did not have a choice (had to use MP3s for half of the tracks, which I seriously doubt), or
- said mastering engineer has (or at least had) no clue what a spectrogram is and what its benefits are, and does not have the ears to distinguish an MP3 from an uncompressed source, and therefore made a serious mistake (I'm pretty sure of that), or
- contrary to the beliefs of some (or most?) of the audiophile community, an MP3 can be transparent even if it is almost one hour long (I'm pretty sure of that as well)

Chris
The first possibility is the one I´d expect the most from Varèse Sarabande. I truly believe that the mastering engineer did recognize the problem (almost every DAW has a spectogram or at least a frequency meter and a mastering engineer would literally have to be blind) and she did inform Varèse about that. They in turn said "We don´t care. Our buyers won´t hear it anyway because we doesn´t. And providing them with lossless tracks would be more costly". So the mastering house had to use this source. Remember, many mastering engineers are destroying material on purpose (Loudness-War) because the money givers say so. Same case here IMO.

And please be careful. You can´t say that audiophiles are generally stupid because of this CD. I´d describe myself as a parttime audiophile. And it is true, I wouldn´t have recognized the compression on this disc if I wouldn´t rip and upsample every little tidbit that goes inside my DVD-ROM. But this fact alone is no proof that MP3 is transparent. It is merely a staunch proof of the fact how conditioned we are. I expect pristine sound on CD and from years of buying CDs I grew accustomed to the fact that there is lossless music on them. Up until now, this was true for 99.999999 %. So the simple experience of having lossless CDs for around 20 years created a placebo effect. Yes, the same placebo effect that normally creates sound differences with some dubious little thingis. A placebo effect of listening to pristine sound.

Truth to be told, the sound is perfectly allright. But I still wouldn´t say that it is transparent. It is really good, but not transparent. Once you know about the possibility of an imperfect CD you can search for artifacts and that´s what I did. Another truth to be told, I don´t know many artifacts when I hear them. During researching this CD I found that MP3 actually had evolved. Music sounds really good even with 160 kbps and for the live of me, I can´t hear a difference from 16/44.1 to 320 kbps MP3. Now I´m using WavPack lossy for two years. And WavPack lossy does have other artifacts (in fact, only one). I had to listen to some selfmade MP3s with a low bitrate to find out again how MP3-artifacts sound.

So, since I´m not experienced in this matter I came here to find out where the artifacts are. But as one person said, it is difficult without a reference.

I for my part have given up. Varèse will not remaster this CD, they will not answer my mails. Instead I created with the help of WaveLabs Spectralizer additional frequencies above 16 kHz which were mixed afterwards into the lossy stuff. I think it sounds better but I didn´t bother to actually compare that (besides, I did use a bit of equalizing to hide possible effects).

Forgive me for the bashing of your conclusions but I couldn´t let the comment about audiophiles be written there without reply. In my mind it was what happens here all the time, only this time the other way round.
marlene-d.blogspot.com

Regular CDs with lossy compression

Reply #48
And please be careful. You can´t say that audiophiles are generally stupid because of this CD. ... But this fact alone is no proof that MP3 is transparent.

Cavaille, I never said or even implied that audiophiles are stupid! Sorry if I was unclear. What I wanted to express is that lossly compressed audio can be transparent, or in other words, of more than sufficient quality, even to a mastering engineer which is used to high-quality recordings (as the "G.I. Joe issue" showed). It seems that some (of course not all) audiophiles don't want us to believe that. Of course that's no proof that it always is transparent.

The thing with Varèse: Why would providing the mastering house with lossless tracks instead of MP3s be be more costly? Transmission over the Internet has never been faster. If it's the producer's fault, they could easily have re-sent the tracks at no extra cost. Unless the mastering engineer already mastered the MP3s... which is what I think happened.

But I give you that, a good mastering engineer would probably never apply loudness-war compression levels from personal belief, but only because the money-givers want it that way.

Chris
If I don't reply to your reply, it means I agree with you.

Regular CDs with lossy compression

Reply #49
But I give you that, a good mastering engineer would probably never apply loudness-war compression levels from personal belief, but only because the money-givers want it that way.

I'd like to believe that, but in a thread at some hi-fi forum (linked from here some time ago and I don't remember either forum, exact comments or anything), users/testers(/other mastering engineers?) were praising a mastering engineers work high above the sky for it's "hotness" - Which are mastering-engineers general term for "compression/limiter-abuse".

Quote
- said mastering engineer has (or at least had) no clue what a spectrogram is and what its benefits are, and does not have the ears to distinguish an MP3 from an uncompressed source, and therefore made a serious mistake (I'm pretty sure of that)

It seems to me (from the spectrogram) that the lossless-part recording has picked up a 16khz sine probably from a tube-tv... Which leads me to think that more than said "mastering "engineer"" both have no idea of what a spectrogram is (and should look like) and lost hearing ability at these frequencies.

A great example of this is Celine Dion's "A new day has come (radio edit)", which has a VERY LOUD 16khz sine in most chorus which are driving ME crazy, but surely didn't do anything to the "mastering "engineer"".
Can't wait for a HD-AAC encoder :P