Barcodes (part 2)

Time to dive further into the barcode information that is stored in Discogs. As I said in part 1: I didn't look much into this subject before, because of the potential huge number of errors I would uncover. After digging a bit further into the data I can confirm that there are indeed many releases with errors. But on the way I found a few interesting things that I want to share.

People can't enter data properly

It is surprising to see how many people added a barcode in the Barcode field and then added a '.' that is not part of the barcode and that even cannot be found in the picture: around 150. I have not even counted things like trailing spaces, soft hyphens (whyyyyy?), and so on.

Text representations of barcodes are not consistent

I looked into some of the descriptions of several barcodes, but they don't seem to describe the barcodes that are in the wild. For example, some EAN-13 barcodes have a '.' in them between the first 12 digits and the check digit, which can be seen on this release (AA side). In total 72 releases with this pattern were found.

Another variation I saw is where the EAN-13 is prefixed with a 'T' (for 'text'?) as can be seen on this ABC release. More than 7800 releases with this pattern were found. That's a bit more than expected.

Yet another variation is where the EAN-13 has 'M' appended, like on this release. There were about 500 releases where I could see this pattern. Another 68 have 'P', like this release.

People enter crap data

There are 591 fields where the barcode field contained a '.' or one or multiple '-' characters, or just spaces. I have no idea why they did this. The most likely explanation is to indicate there is no barcode (for which Discogs really should introduce a better system) or sloppiness.

After filtering (and before checking if these barcodes are actually valid) I still have around 60,000 entries that deserve a closer look. At first sight it is mostly:

rights societies
SID codes
matrix/runout

and a whole bunch of other things. It is a bit of a mixed bag.

In the next part I am going to dig deeper into the releases that I think have a valid barcode field.

Comments

SID codes (part 1)

One thing that I only learned about after using Discogs is the so called Source Identification Code, or SID. These codes were introduced in 1994 to combat piracy and to find out on which machines a CD was made. It was introduced by Philips and adopted by IFPI, and specifications are publicly available which clearly describe the two available SID codes (mastering SID code and mould SID code). Since quite a few months Discogs has two fields available in the " Barcode and Other Identifiers " (BaOI) section: Mould SID code Mastering SID code A few questions immediately popped up in my mind: how many releases don't have a SID field defined when there should be (for example, the free text field indicates it is a SID field)? how many releases have a SID field with values that should not be in the SID field? how many release have a SID field, but a wrong year (as SID codes were only introduced in 1994) how many vinyl releases have a SID code defined (which is impossi...

SPARS codes (part 1)

Let's talk about SPARS codes used on CDs (or CD-like formats). You have most likely seen it used, but maybe don't know its name. The SPARS code is a three letter code indicating if recording, mixing and mastering were analogue or digital. For example they could look like the ones below. There is not a fixed format, so there are other variants as well. Personally I am not paying too much attention to these codes (I simply do not care), but in the classical music world if something was labeled as DDD (so everything digital) companies could ask premium prices. That makes it interesting information to mine and unlock, which is something that Discogs does not allow people to do when searching (yet!) even though it could be a helpful filter. I wanted to see if it can be used as an identifier to tell releases apart (are there similar releases where the only difference is the SPARS code?). SPARS code in Discogs Since a few months SPARS is a separate field in the Discogs ...

Using matrix numbers of CDs to verify release years (1)

One of the first steps when making CDs is to produce a "glass master". From that (using a few more steps) a "stamper" is created which is then used to press the actual CDs. When looking at a CD you can often see text in a ring in the middle of the CD. This is the so called matrix which comes from the glass master. Apart from the matrix other text (like the IFPI mastering SID code) could possibly also come from the glass master. A bit of background information can be found on page 7 of the IFPI SID code implementation guide although I would also highly recommend watching some of the clips about glass masters on YouTube, which are highly informative. One company making a lot of these glass masters is Cinram . For most of their glass masters they stored the production date in matrix. This is good news, because it means that it could possibly be used to verify releases and see if the declared year of the release is right: it could never have been released before...

Vinyl & Data

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