Does emusic use watermarking ?
December 19, 2007 8:00 PM   Subscribe

Does watermark mp3s and if so, what is in the watermark and can you provide technical details on this watermarking ?
posted by pixx to Computers & Internet (18 answers total) 2 users marked this as a favorite
Wikipedia says "EMusic stores a record of user purchases on its internal servers, but does not place any purchaser information inside the tracks that are sold."
posted by danb at 8:06 PM on December 19, 2007

here's one interesting blogpost on the matter.

In the comments there is an Of Montreal song mentioned. try downloading it from emuisc and check the encoding to see if it matches the one in blog. I'd do it myself, but I have a storebought copy not a downloaded one.
posted by robotot at 8:16 PM on December 19, 2007

Check out this fine resource on audio watermarking.
posted by fourcheesemac at 8:55 PM on December 19, 2007

Humm, I'm not sure but it seems like an easy way to tell would be to download the same track using two different eMusic accounts and then comparing hashes. Although a difference in hashes wouldn't necessarily imply they were watermarked (there are other things that could cause them to be different), no difference would pretty much guarantee that they're clean.

Just make sure to get them from two different IP addresses, computers, etc., so that none of the information in a watermark would be the same.
posted by Kadin2048 at 9:04 PM on December 19, 2007

OK, I've just used downloaded that Of Montreal song mentioned above and I get a completely different hash to the one in the blog comments...

Seems they're certainly watermarking their audiobooks, so presumably they'd be doing it for the music too. Looks like they were doing it in 2000 anyway.

Doesn't really bother me though. Should it?
posted by ComfySofa at 2:51 AM on December 20, 2007

Response by poster: It's definatly their right but there are implications that are consumer unfriendly. Your name stays stamped on a file that can get accidentally lost and for which you could eventually be accused of infringement. It adds a serious burden of data destruction on the user. Your files may get stolen. Is there a mechanism for declaring that ? Kind of like saying that a CD bears your name forever and you do not have the right to loose it and you must physically destroy it when you are done with it. Also, I think it would be honest and quite effective in preventing copying to at least be upfront about it. But as with other DRM schemes, it is against the consumer.
posted by pixx at 4:13 AM on December 20, 2007

As of June 2007, they were not.
"We don't put any identifying info on our files," said Cathy Halgas Nevins, a spokesperson for eMusic.
posted by smackfu at 6:25 AM on December 20, 2007 [1 favorite]

here's one interesting blogpost on the matter.

Looking through that blogpost, aside from claiming that eMusic uses watermarking, they provide no evidence though the comments do provide some good insight.

I wouldn't be surprised if they watermarked books without watermarking music tracks. The book industry is very leary (even more so than the music industry) about filesharing to the point that Penguin pulled out of eMusic's book service shortly after it began because of the lack of DRM.

Doesn't every iTunes store track contain data about who bought the track?
posted by drezdn at 6:53 AM on December 20, 2007

I see that smackfu's link answers the itunes question.
posted by drezdn at 6:53 AM on December 20, 2007

I'm an emusic subscriber. One clicks the appropriate link and the songs begin downloading *immediately*. Surely, if watermarks were being added to the tracks I had picked, there would be some sort of a delay before downloading where the tracks were being watermarked. I'd say this is strong evidence that they don't alter the tracks for individual downloads.
posted by maryrosecook at 7:40 AM on December 20, 2007

Response by poster: I agree the downlaod speed is a good indicator. There would have to be a delay.. I am also a (happy) emusic subscriber.. Anyone want to test by downlading a given file and doing a checksum compare with me ?
posted by pixx at 8:21 AM on December 20, 2007

Response by poster: Actually, download speed is not a clear indicator as the files could have "serial numbers" built in advance..
posted by pixx at 8:23 AM on December 20, 2007

Send me a link to the track you want me to download and I'll do it.
posted by drezdn at 8:35 AM on December 20, 2007

Download it that is and send it to you for comparison.
posted by drezdn at 8:36 AM on December 20, 2007

I get an MD5 of c1d3b98f7470362b95c367a30dc86816 for the Of Montreal song mentioned, with file size 4712066 bytes. I think the reason this is different from the one in the post robotot linked to is because eMusic started including album art in the files fairly recently.
posted by yarmond at 9:28 PM on December 20, 2007

The hash I got for the Of Montreal track was c1d3b98f7470362b95c367a30dc86816 and the file size was 4,712,066 bytes too - so everything is hunky dory and emusic are not evil. Hooray!
posted by ComfySofa at 2:38 AM on December 21, 2007

There would have to be a delay

The simplest way to add an identifier is to add a tag to the ID3 fields. Not robust like a real audio watermark, which are intended to survive conversion from the MP3 format. But very quick to add, and if you use an ID3 field that is not normally shown to users, virtually invisible. I think this is how Amazon adds tracking info to their MP3s.
posted by smackfu at 7:40 AM on December 21, 2007

Response by poster: Thanks for testing people !

So for posterity as of December 21 2007, eMusic is NOT EVIL and does not seem to use watermarking at al.. Yay !
posted by pixx at 8:08 AM on December 21, 2007

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