This is my personal blog. The views expressed on this page are mine alone.
Update, April 8, 2013: Can you hear it? Take the watermark listening test.
Update, January 14, 2015: Check out the results of the listening test.
A while ago, I wrote about my confusion regarding Weird Spotify Compression Artifacts. It turns out the artifacts I was hearing are not due to compression, but a result of audio watermarks that Universal Music Group embeds in digitally distributed tracks. This watermark is embedded in UMG tracks on Rdio, Spotify, iTunes, Tidal, and others. The watermark can also be heard in Universal tracks broadcast over FM radio. Universal Music recordings make up about 25% of most online catalogs, and its labels include Interscope, The Island Def Jam, Universal Republic, Verve, GRP, Impulse!, Decca, Deutsche Grammophon, Geffen, etc.
What the watermark sounds like
Spectrogram of the difference between a watermarked and unwatermarked UMG track. The energy is concentrated in two bands between about 1 khz and 3.5 khz - where the human ear is most sensitive.
UMG uses a spread spectrum watermark, a technique explained in detail in this Microsoft research paper. The watermark scheme modulates the total energy in two different bands, 1khz to 2.3 khz and 2.3 to 3.6 khz. The energy is concentrated in the most perceptually sensitive frequencies because that makes it more difficult to attack or remove without significant audible distortion.
The energy is increased or reduced in 0.04 second blocks. The result can be characterized as a fluttering, tremolo sound. Listen closely to the original vs. watermarked audio samples and try to focus on the 1 khz to 3.6 khz noise range. It helps to wear headphones in a quiet environment.
Audio samples
Here is a short sample (excerpt: Three Doors Down - When You're Young). These are lossless original and watermarked files; what you hear is not a result of compression.
Original:
Watermarked:
If the difference between the two isn't clear, here it is by itself:
Difference:
The character of the watermark may seem subtle during this short sample, but through the duration of an entire song it becomes more familiar and more annoying. Check out my original post on the subject for more examples.
Technical details
The watermark does not start until 1 second into the audio. After this the signal is divided into 0.08 second blocks. Each block is divided in two: some amount of energy is added to the first half and the same amount is subtracted from the second half. This coding scheme allows blind detection (without access to the original file). The actual information in the watermark is not easily recovered because it is modulated by a pseudo random sequence, which is generated by a secret key.
I did a little searching and it seems this watermarking technology is provided by MarkAny, a Korean company that has developed their own watermarks out of university research, and purchased some watermarking patents from Digimark.
Removing the watermark
Since the watermark creates audible distortion, it's worthwhile to try to reduce it. I wrote a MATLAB script that analyzes the block energy and applies some smoothing. This is the result:
Watermarked:
Restored:
More discussion
Hydrogenaudio forums on watermarking
UMG Watermarks audiophile files, pisses off paying customers
Why do labels watermark tracks? Watermarking simplifies copyright enforcement by letting a company track music on peer-to-peer networks. "It gives them the ability to put pressure on policy makers and ISPs to do filtering," says Fred Von Lohmann, an Electronic Frontier Foundation attorney. That may be about the best explanation you will find. See DRM Is Dead, But Watermarks Rise From Its Ashes
Most listeners probably don't notice the watermark in the music they listen to. The audibility of the watermark is very content-dependent; classical, and solo piano in particular, are affected most severely. I've seen complaints on classical music forums with descriptions calling out the characteristic fluttering of the watermark. These listeners might be acutely aware of these sound quality problems, but blame lossy compression or streaming services.
I don't think there is anything inherently wrong with watermarking. The problem is with this particular poorly tested implementation. It is unfortunate considering the amount of engineering effort that goes into every music production.
Alex Jimenez
/ February 4, 2012 QuoteThank you for figuring this out. I use Spotify and like many had thought something was wrong with the streaming codec. It's also being used on iTunes, judging by a recent LA Philharmonic download of Wagner excerpts--the irritating flutter is there too.
Taylor Perkins
/ June 12, 2012 QuoteThis is great analysis.
bozmillar
/ September 10, 2012 QuoteI've been wondering what this flutter was for a long time. Thanks for putting this up. I always just figured it was a compression issue, but when I upgraded spotify to the "high quality streaming" and it was still there, I got suspicious and found this.
George
/ September 28, 2012 QuoteHi;
How did you obtain a difference wav ? What tool did you use ? I have a CD and an official download and wanted to check for myself.
Thanks;
George
Kasper Holbek Jensen
/ October 4, 2012 QuoteVery nice brief analasys for non-soundtechies like myself, I was wondering if the smoothing script is of up grabs. Or would that violate some term/law?
Matt
/ October 4, 2012 QuoteI didn't post the script since distributing it would probably violate the DMCA, but it is pretty easy to duplicate if you know how to work with audio in the frequency domain...
Matt
/ October 4, 2012 QuoteI generated the difference audio by aligning the signal of the original and watermarked audio and subtracting them. You can do this in any wave audio editor like Audacity or Adobe Audition, but the sample alignment is the most important part.
Kasper Holbek Jensen
/ October 5, 2012 QuoteI wouldn't know where to start. It is a strange thing that the real quality audio is now reserved for the pirates. This industry really knows how to hit a target.
B. B. Pedersen
/ May 13, 2013 QuoteThanks, shared.
George W
/ May 13, 2013 QuoteI think they thought they were really clever this time. Since virtually all music consumption today is via online listening, (read Youtube &Co) so people neither notice nor care.
Most of the few who actually pay for music are playing it through the laptop USB speakers, (read Spotify &Co) which often aren't exactly HIFI. And most grown-ups don't hear the difference anyway. (I tested the given samples with Sony headphones. And my hearing is flat to a 12kHz personal cutoff, which is average for my age.)
So, the only ones to really suffer must have good hearing and a proper stereo set. But many of them do actually buy CDs, so that's even better for the industry. :-/
Now, I do agree about watermarking in general. I think it is OK to watermark your intellectual (or alas, your artists' intellectual) property, but it shouldn't degrade paid-for music.
At any rate, this is a step towards sanity compared to copy protection. I think we are on our way to a better future because every year an old boss retires, and instead comes a younger one, who's presumably seen computers as a child.
Matt
/ May 14, 2013 QuoteGeorge - I want to offer a small counterpoint to a few of your statements. It might be that listeners with poor hearing or cheap stereos actually hear the watermark more prominently. Consider that a cheap stereo system will have a low and high frequency roll off, such that only the midrange is left over; the watermark is concentrated in the middle, unaffected. However, played over a hi-fi system, there's more energy in the highs and lows, and that's just more energy that might mask the watermark in the middle. Likewise, for someone with some hearing loss, unless their hearing loss lands right on 1 to 3.6 kHz, they're simply going to be deaf to acoustic energy that would otherwise serve to mask the watermark.
Pål Bråtelund
/ May 15, 2013 QuoteThanks for this analysis, Matt. All this is in a lossless domain - got any thoughts on how the most popular codecs (AAC, Vorbis and MP3) reacts to spread spectrum watermarks?
Matt
/ May 15, 2013 QuoteThe watermark is designed to withstand lossy compression. You'll still be able to hear it in a 64 kbps MP3, for example.
RM
/ June 6, 2013 QuoteThanks a lot for the info given here.
I recently subscribed to Qobuz because they are the only ones who stream lossless. However, the Universal tracks do have the digital watermark. Listen to the first seconds of Shostakovich's 8th symphony conducted by Valery Gergiev (Philips). It's simply unlistenable. I'm not willing to pay for audio that is degraded in such a way. Bad for Qobuz which is really a great site otherwise.
RM
/ June 6, 2013 QuoteSorry. I have to correct my statement above about watermarking at Qobuz.
I bought one track I had on CD (Track 1 of Boulez' Miracoulous Mandarin on DG). I did an inverted mix paste, and the result was digital silence. So obviously they were bit-identical. So at least with this one example, there is no digital watermarking of Universal tracks at Qobuz.
Maybe the Gergiev is just a crappy recording (I can't compare).
Kevin E
/ July 16, 2013 QuoteThanks for this! I can't believe there hasn't been more uproar over this. There is an Avett Brothers single on the radio these days that has such horrendous watermarking that I want to rip my hair out every time i hear it.
If anything, watermarking will just incite more piracy. From now on, I certainly won't buy anything under the UMG umbrella on Amazon or iTunes.
q2
/ July 31, 2013 QuoteWhat's the name of the piece in the first audio example of your A-B test?
Matt
/ July 31, 2013 QuoteIt is by Ravel. Daphnis et Chloe - Troisième partie (Part 3) - I. Lent.
q2
/ July 31, 2013 QuoteThanks!
tahrey
/ September 5, 2013 QuoteSo that's why some songs on the radio (and played by less classy wedding DJs :D) have sounded so crap of late...
frodowiz
/ November 19, 2013 Quotefreedom isnt free. if no one bought music from distributors who watermark, AND let them know why, and demanded money back for distorting their music purchase. you get the idea.. people can complain all they want but big industry is only going to get worse, more greedy. however, you can count on greedy business to do whatever they need to do to maximize profits and that means no watermarks if no money is made from them. with the current dictatorship here in america run by the entertainment giants, you are in for a long fight.
barring that, here is my other suggestion. develop software that writes watermarks in the same fashion as the watermarks you are trying to remove. use this software to write new watermarks. various tweaks, namely phase change for the method above and other tweaks for other methods. the idea is to erase, or minimize or overwrite(depending on type) the added watermark enough it fails at its original purpose. this isnt so difficult to conceptualize and a case can be made for removing the watermark as it borders on malware in part by allowing other code on websites for instance or media players to target ads at you. it is malware. but sadly, while the author of the site and a few others do their share in educating, the masses still go back for good kick in the a** only to send the message to the music industry that they are willing to put up with it. yes, shake your fists and type at the top of your lungs friends. no hurry and grab lady gaga's latest.
dual lufsig
/ December 25, 2013 QuoteFuxk UMG.
Some suggestion on the listening test: Some type of music (piano) can easily reveal the watermark while some (fast/percussive/loud) are much harder to identify that I actually gave up testing. It's better to add an "I can't hear" option to make the statistics more useful. Also, can you publish your statistics to show which music clips have the highest identification rate? Thanks.
Bucket O'Toules
/ January 1, 2014 QuoteThis entire post. Yes. Unless we hit them in the pocketbook. Good luck on that because certain demographics only care about the hype that the record companies and other big industry creates. Without thinking and nearly as a majority bloc, they buy into the bling, the rims, the grills, the twerking, the stupid antics, and other "culture" and prop up the corporations. We were given brains for a reason, and unfortunately, a majority of the population still operates on a base, animal level. Big Industry, as a creature of its own, adapts easily to this highly positive reward/response cycle.
So ... unless we stop consuming ... we will have to suffer for our pleasures.
Philly Bob
/ January 13, 2014 QuoteVerance has one also that was used in the MLP section of DVD-Audio discs.
It's purpose was to prevent copying of the discs.
When a copied disc was played in a unit that detected the watermark, the playback would halt after 15 or 30 seconds.
This watermark too, was noticeable.
It is reported that it too, was able to be beaten.
John Kristian
/ February 24, 2014 QuoteThank you for a very good summary.
I was wondering if you could analyze this track:
http://open.spotify.com/track/439riMf3Je9jTGdLQ1xDBd
It has noise at a very low frequency that makes your subwoofer/bass "pulsate" constantly. It's easier to see it on your woofer than to hear it. It's a bit scary when you're playing at high volume, you might reach your drivers XMAX.
I don't know if this is a bug in the mix or a watermark. It's the same phenomenon on both spotify and Wimp HiFi (lossless)
John Kristian
/ February 24, 2014 QuoteI scored 15/16 on the watermark test on the first try (track 12 was difficult). I'm astonished how bad this watermark affects the sound quality.
A half bad MP3 rip would often sound better. It's clear and simple fraud if you ask me.
Matt
/ March 7, 2014 QuoteHi John, the tracks are randomized, but you're probably talking about one of the electronic tracks. The audibility of the watermark is very content-dependent. Solo piano and classical are affected most severely.
Rainer
/ November 30, 2014 QuoteI downloaded Claudio Abbado's Symphony Edition (DG) from Qobuz in flac format. I was wondering why none of the albums verified ok with the Cuetools database. In an audio editor, I compared one track which I also have on CD (Mahler 4) with the download. There it was: Small deviations that form a regular pattern much like in the image above.
I feel cheated, I must say. I'm an audiophile paying for the stuff, so don't expect degraded quality by digital watermarks. My confidence in buying digital downloads is gone. Dear Universal Music Group: This is really stupid.
Reactorcore
/ January 14, 2015 QuoteAww, I thought this going to be a parody, where the watermark turned out to be some evil satanic chanting sound. : p
Blue Spike
/ February 7, 2015 QuoteSome reasons for audibility has to do with how modulation of the audio needs subsequent noise shaping (if the MSFT paper is believed). Green Room's Tony Faulkner observed these artifacts famously during the days of SDMI. There are inaudibile approaches that are deployed and available. Lots of #innovation in this field required patented technologies.
Blue Spike
/ February 7, 2015 QuoteForgot. We did one of our earliest deployments (tested at Criteria Studios) with 'Cane Records. Had a party at Hard Rock for the introduction of the 1995 release. Jim Progris (sp) was our contact (the Co was not yet Blue Spike) and UM had graduate student and good friend Eric Alexandrakis do the testing as he produced that release. It's discussed in the August 7, 1995 New York Times by journalist Denise Caruso (http://www.nytimes.com/1995/08/07/business/technology-digital-commerce-2-plans-for-watermarks-which-can-bind-proof.html)
Great that you are willing to discuss this. We've got profiles on most of the deployed systems.
ERIC ALEXANDRAKIS
/ February 7, 2015 QuoteTake it from Scott Moskowitz of BlueSpike. He invented the bloody thing, and together we put out the first digitally watermarked CD in 1995. 20 years ago...and 20 years ago upon its first implementation, this type of horrible garbling noise didn't exist. Why anyone would deploy something as noisy as this, with noise shaping after modulation, instead of encoding, makes no sense. It's like taking my vintage car and drilling holes in the doors and frames, to run padlocks through for protection.
Charles Hansen
/ June 11, 2015 QuoteWow -- this is incredible! Don't these guys get it? Audible watermarks were a disaster 15 years ago and they are repeating the same mistake?
Thanks so much for this. This deserves much more attention and some concerted action. Unacceptable behavior from UMG.
Did they ask the artists if they minded if their music was butchered?
Coincoin
/ July 23, 2015 QuoteUnfortunately nobody gives a shit anymore because they think it's compression. People are so used to crappy music unaffected by this problem that they will never fix it this time around. I can't stand listening to anything from UMG anymore. They butchered wonderful music to a pulp.
yh
/ December 10, 2015 QuoteI'll sincerelt admit that, when it is not isolated, I fail to hear it 😀 (meaning that the average listener won't be bothered either, in my opinion).
Michael Woodley
/ May 12, 2016 QuoteWell, if UMG had chosen to use Intrasonics audio watermarking technology, which is based on echo modulation and not DSSS (noise modulation), there would be no audibility in these tracks.
Find out why echo-mod is superior: http://www.intrasonics.com/how-it-works/
Don Ho
/ June 12, 2016 QuoteThe silence on this matter is deafening when this question is asked of Pono.
A High Definition music player AND download service.
BUT
Offend someone in their socail forum and watch how fast they respond to THAT.
http://WWW.PONOSUCKS.COM
Nigel
/ October 27, 2016 QuoteThank goodness I found this blog and associated 'can you tell' test! I only scored 12/16 but it was a noisy less than ideal listening environment. I was just about to splash out on Tidal "HiFi" having been with Spotify for a few years, but am having second thoughts! The tremolo flutter effect on strings and tape hiss on one on my standard test pieces (Mercury Living Presence recording of 1812 overture the latest 1955? one) is almost beyond belief. Same recording on Spot at 320k shows no such sign. Shame because I was starting to be convinced by Tidal until I started hearing this flutter effect on more and more tracks. So I won't be continuing after the trial. Thanks for all the analysis etc , I shall be keeping an eye on things to see what if anything Tidal does about it.
Nigel
/ October 28, 2016 QuoteAfter careful listening in a quiet room on Sennheiser 540s I can detect the watermark on the Spotify 320kbps track but much less objectionable than Tidal HiFi. Maybe a case of lossless revealing 'warts n all'?!
Daniel Brown
/ December 2, 2016 QuoteMatt,
Thank you so much for your work, and publicising this horrible watermarking practice from UMG and its subsidiaries.
I primarily listen to CDs or flac rips from those CDs, or streaming radio that happens to not have any corrupted UMG content, so I never ever had a chance to hear any of these artifacts. I decided to try Tidal, and am initially impressed, ~2 weeks in to the 30 day trial. I though it would be perfect to have for holiday season/parties.
Then I got to a few tracks that just didnt sound right, the whole album sounded funny. Figured it was some compression, or an upsampled version of a previously compressed file they were sneaking in even though it was "Hifi lossless CD quality FLAC" So I went back to look at some of the Tidal vs Spotify reviews, and found a link to your site in my travels.
I did your A/B test and scored 16/16 listening on ~25 year old $100 Denon headphones plugged into the headphone out on my PC in a quiet home office. Yay. But alas, I cant ever un-hear this noise now that I know exactly what it is. I cant dismiss it as oh a bad encoding, or a screw up in something or snuck in compression, or an upsampled copy of an originally compressed file ( which I suspect a lot ).
Anyways, thank you again for exposing and testing and proving the UMG shenanigans. I am passing this info along to anyone I know who cares at all about music.
Echoing what I have seen a few others post online.. this should be a "scandal" and UMG should undo this nonsense.
Thanks,
Daniel Brown
Tor
/ December 6, 2016 QuoteHi.
I first Heard these artifacts with a song I found online a few years a go, I first thought it was Itunes m4a compression.
Now I got a subscribtion to Apple Music, and I've Heard the artifacts in some of the songs.
Go and listen to a song by Owl City called Peppermint Winter.
I don't Think this song has ever been released on cd. It was only released as a single a few years a go, and yes I definetly hear the watermark artifacts, especially at the beginning of the song.
James H
/ February 23, 2017 QuoteWhat service did the watermarked sample file come from in the example above (Rdio, Spotify, iTunes, Tidal?).
And is this still happening with current releases?
a listener
/ February 27, 2017 QuoteYes, the watermarking is still happening. It's also being used by UMG on high resolution releases.
Jochen Goerdts
/ March 22, 2017 QuoteThanks, Matt, heaps for pointing this out. On my Electro Voice Sentry III I have thought the tweeters would have been subsidiarized into a no-brainer.
LG
Jochen
Bob Marley
/ April 12, 2017 QuoteIs there a software or a foobar2000 plugin (like a DVD watermark plugin) for detecting UMG's watermark?
Any examples of HiRes songs with audible watermark?
Honestly I haven't noticed any audible watermarking on HiRes tracks so far and Mastered For iTunes tracks seem to be clean from it. At the same time I've noticed obvious watermark on a CD of Black Sabbath's "13" album! Awful stuff really.
Paul
/ May 26, 2017 QuoteWell now, I guess, I will always be a bit biased especially when I listen to my Qobuz purchased tracks - especially the ones under UMG label...
Although I could not identify the watermarked track in the listening test on every sample - for the ones where I COULD identify it, it was really annoying. Thanks for that post, for the listening test and for enlightening me.
Now I wander what would be the best way to get around watermarked music when buying an album: In the last month I switched over to not buying CDs any more but buying the music on Qobuz instead. But having that watermarking in mind, wouldn't it be better to go back to CDs again and ripping them into my flac collection? I did not find any information if CDs also suffer from watermarking, or if only online / download content is affected.
betorov
/ August 4, 2017 QuoteI must say, I can't hear this thing anymore on Spotify. Is this thing history then? Or maybe someone has a super obvious example to share.
Peter
/ August 8, 2017 QuoteI listened to Mahlers 5th symphony on Tidal HiFi this evening. The 1993 recording by Abbado with the Berliner Philharmoniker for DG. It's also on Spotify.
Is what I am hearing in the trumpet solo in the beginning of the first movement (0:17~0:21) the watermark effect? I thought something was wrong with my DAC.
Matt
/ August 8, 2017 QuoteYes, listening now, that's the watermark.
Peter
/ August 9, 2017 QuoteThat's ridiculous. Here I am subscribed to a HiFi streaming service... It's clearly audible, all throughout the performance. Very sad. I can't imagine artists not being furious and protesting about this. Anything known about that? Especially in classical music.
Where in the process is this watermarking added? Is it certain that the coding isn't also added to CD masters? I mean, these company's know that CD's get ripped and and up on the net, so...
Peter
/ August 9, 2017 QuoteI do want to add that I am completely for record companies trying to protect their recordings against piracy, by the way.
I am trying to support these companies and the music business as much as I can. This is precisely why I am so dissapointed by this.
CyberGene
/ August 10, 2017 QuoteI just posted the following on the Apple communities where there's a link to this website.
I've been having the same problem with DG records on the Apple Music streaming service since the very beginning of the service. I always thought it was due to some AAC-encoding issues and I've reported that to Apple and we had a long conversation going as far as me sending them my own CD-rip excerpt of the same record with no audio issues for them to compare against their version. Ultimately they acknowledged they can hear the difference (the particular record in question is the 17-CD set of complete Chopin music where this is audible all the time since there's a lot of mellow solo piano passages almost everywhere). Here's their answer:
They never mentioned about any digital watermarking so I thought it was just something like DG using wrong sample rate conversion or whatever but I grew so tired of this problem that I started avoiding their releases and preferred other classical music labels on Apple Music. But whenever I encounter this problem, which is audible on more than half the DG releases, I get very irritated. It is today that I was finally fed up and decided to search on the Internet if there are other people who have this problem and here I am.
What can I say, this is just totally unacceptable. This is the kind of behavior that can make me enraged to the point I will intentionally reject UMG releases and will force myself to listen to other music companies.
Andrew
/ January 9, 2018 QuoteI'm hearing extremely obvious artifacts now on broadcast radio, especially when you hear audience applause or other complex sounds. It just started on WBZ exactly after iHeart Radio (screw them), bought the station (RIP). But before that, very obvious on NPR (Wait, wait, Don't Tell Me, for example). Is this watermarking too? What is it? They are killing broadcast radio now.