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Watermarking: what do we know?

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andreasmaaan

andreasmaaan

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I have both Tidal and Qobuz. Don’t know how to snip. Tidal has, just checked, 3 months trial for €1. I will owe you a beer for that one :)

Haha fair enough. Am on holiday in Krakow at the moment but will get onto this first thing in the new year :)
 

Soniclife

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Problem is, I don’t subscribe to Tidal! If anyone does subscribe, and can provide some snippets for comparison, I’d be happy to see if I can get any meaningful data out (no promises I have the skill to do so however).
I have tidal and can help with this, I've just tested with audacity recording the wasapi stream, PM when you have time.
 
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andreasmaaan

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I have tidal and can help with this, I've just tested with audacity recording the wasapi stream, PM when you have time.

Nice! Thanks. Is it possible to record anything there of which you have a purchased copy of the same master at the same resolution? I need both pieces of the puzzle to compare them :)
 

Soniclife

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Nice! Thanks. Is it possible to record anything there of which you have a purchased copy of the same master at the same resolution? I need both pieces of the puzzle to compare them :)
Any specific label that might be worth starting with? Most of my music is not on major labels so it might be an interesting challenge.
 

Soniclife

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Tidal has watermarks, from what I can tell at least.

I finally got around to doing some comparisons, thanks to Delta Wave, which turns out to be so easy to use this idiot got sensible results out of it.

An example of what a delta sounds like, mp3. Sounds like a scratchy old modem to me, with some music way underneath.

And they look like this.
Screenshot 2019-04-10 17.22.37.png

Screenshot 2019-04-10 17.41.00.png
 

amirm

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I finally got around to doing some comparisons, thanks to Delta Wave, which turns out to be so easy to use this idiot got sensible results out of it.
Very clever use of the tool!
 

Soniclife

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I'd like to know if Qobuz also suffers this, I expect it does. From what I could see MQA tracks are not watermarked, and the one track I looked at on Deutsche Grammophon as a classical test wasn't marked either, but it was a quiet track which might stop the marking kicking in.

Who has thoughts as to the audibility of this, 50db down from the full scale sounds like it's probably well masked.
 

hvbias

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Tidal has watermarks, from what I can tell at least.

I finally got around to doing some comparisons, thanks to Delta Wave, which turns out to be so easy to use this idiot got sensible results out of it.

An example of what a delta sounds like, mp3. Sounds like a scratchy old modem to me, with some music way underneath.

And they look like this.
View attachment 24715
View attachment 24716

Can you post more information how you generated this? Or is it just opening a music file in the program :)
 

Soniclife

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Can you post more information how you generated this? Or is it just opening a music file in the program :)
I took a flac file I had ripped from CD, then captured the play back of that track in roon using audacity recording what was sent to the soundcard. Then I compared this using delta wave, this gave a deep null. I then recorded the same track playing from tidal, and compared that to the flac, the results of that are above.

I wasn't confident in all cases that I was comparing the same master, so I did my best to try and pick things that were unlikely, as I thought to have had a remaster. I was able to get deep nulls between flac and tidal with some tracks, so not so tracks have the watermark.
 

RussellH

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My company (microsoft) participated in the first round of call for proposals for watermarks for music. For the longest time, content owners keep thinking this is a way of copy protection. It is not. All you can do is trace the content to the one with or without watermark. We (tech companies) adamantly fought the notion of using it for "copy control" and for the most part won. Proposals for example to only play music that has the official mark in them were thrown back at content owners and not implemented.

Back to watermark, it has multiple vectors:

1. How long of a mark needs to be inserted. 8 bits is easier than 64 bits. The more bits needed to be inserted, the more bits in music will need to change.

2. What is the shortest duration of music where the mark can be detected. Content owners want the shortest duration but from fidelity point of view, we want to hide the bits where they are least audible. If it takes 30 seconds, so be it. But this lengthens the forensic work to find the mark so there is always pressure to insert the mark/detect it in fewest seconds (e.g. 10).

3. How much CPU it takes to detect it. This is so that cheap embedded devices can find the mark and act on it. As is typically the case, simpler algorithm is less sophisticated in its ability to hide the mark.

4. Patent liability (i.e. risk of claims).

5. Cost of using the mark both in content and devices.

6. Resilience to damage due to data errors or transformation (e.g. encoding into MP3). For this reason, the mark data is hugely replicated. So what starts at 64 bits to be embedded, may turn out to be 64,000 bits you need to embed in the music.

All of these factors come into play before a label chooses a mark to embed. When at Microsoft, we proposed a sophisticated scheme that we thought did well in all of this but required a lot of CPU cycles. We lost out to a much simpler scheme that we thought was not sufficient at all.

I don't know what watermark technology is used these days. But the goal is always to reduce its audibility. To put it in context, it would be a lot easier to hear MP3 compression than a watermark. So I don't think most people will be bothered by it.


"So I don't think most people will be bothered by it. "

That turned out to be wrong for classical fans. For solo piano, I would much rather listen to mp3 128 bps un-watermarked than Hi Res watermarked!
 

Kvalsvoll

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I took a flac file I had ripped from CD, then captured the play back of that track in roon using audacity recording what was sent to the soundcard. Then I compared this using delta wave, this gave a deep null. I then recorded the same track playing from tidal, and compared that to the flac, the results of that are above.

I wasn't confident in all cases that I was comparing the same master, so I did my best to try and pick things that were unlikely, as I thought to have had a remaster. I was able to get deep nulls between flac and tidal with some tracks, so not so tracks have the watermark.

Interesting. I did a Tidal compare once, and found it to be bit-perfect. Which of course only shows that it is possible to get a bit-perfect streaming, but that is obviously not necessary the case for all music.

I seen no obvious flaws in your analysis. If they were different masters, the difference should be much larger, and also be present at higher frequencies. So unless someone can point out some kind of error in this analysis, this shows indeed that the tracks are different.
 

Soniclife

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I seen no obvious flaws in your analysis. If they were different masters, the difference should be much larger, and also be present at higher frequencies. So unless someone can point out some kind of error in this analysis, this shows indeed that the tracks are different.
I was hoping someone else would repeat my test, to confirm or refute my claim, I'm open to the idea I did something wrong.
 

Purité Audio

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I recently discussed watermarking with a senior representative of Universal Music, he said there was watermarking, years ago but believed it had stopped , years ago, I have asked him to confirm the current situation.
Keith
 

hvbias

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I was hoping someone else would repeat my test, to confirm or refute my claim, I'm open to the idea I did something wrong.

I have been meaning to, but been quite busy.

I recently discussed watermarking with a senior representative of Universal Music, he said there was watermarking, years ago but believed it had stopped , years ago, I have asked him to confirm the current situation.
Keith

He was not being truthful (or maybe simply didn't know). I heard it on some Tidal classical streams. Try it on string quartets (really any chamber music), solo piano or violin. Those are the easiest to hear it on, but any trained listener will be able to pick it up on most classical recordings that have it.

Even with hi-res downloads from the Universal label, I only know of one instance where a HDTracks download that was watermarked was corrected and the proper non-watermarked files sent to the customer.
 

Purité Audio

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Perhaps you could post a link to some recently released watermarked and non watermarked versions and I can again put the question to him?
Keith
 

Soniclife

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Perhaps you could post a link to some recently released watermarked and non watermarked versions and I can again put the question to him?
Keith
I used Incesticide by Nirvana when I did my test above, they were on Geffen, I'm unaware of any remaster being done on this album. Make sure you ask about streaming specifically, and not just CD.
 

Kvalsvoll

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I was hoping someone else would repeat my test, to confirm or refute my claim, I'm open to the idea I did something wrong.

One can only guess what is going on behind the scenes. A likely scenario is that Tidal has little control of what material is made available, this is up to the content providers and owners of the music. So it would be possible for one provider to watermark content intended specifically for Tidal streaming, for the purpose of seeing where copies that violate copyright originate from.
 

Soniclife

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One can only guess what is going on behind the scenes. A likely scenario is that Tidal has little control of what material is made available, this is up to the content providers and owners of the music. So it would be possible for one provider to watermark content intended specifically for Tidal streaming, for the purpose of seeing where copies that violate copyright originate from.
I'm sure it's the labels doing it before handing over to tidal etc, as it's limited to specific labels. I'd like to know if qobuz is affected.
 
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