CD song information - how do it know?

I’ve been importing my CD’s into iTunes today and I was pretty impressed at the way that no matter what CD I popped into the player, it knew the artist, album, and genre of whatever disk.

Amazingly, it even worked with my college buddy’s garage band CD made way back in 1992, back when a CD player was still a novelty on a PC, long before iTunes was a even gleam in Steve Jobs’s eye. I know for a fact this physical CD was pressed in 1992 in a small run of 500 and iTunes still picked up my buddy’s name, the album name, and every track name. I was floored.

So how does this magic actually work?

Just for kicks, next time you put put a CD in, unplug the computer from the internet. I belive that’s where it get’s it’s info.

That makes it even more amazing. The obscure CD of which I speak, like many others I imported tonight, were pressed and distributed before the Web (1992).

So does that mean somebody went back and… um… for lack of a better term, keyed the information into teh intarwebs after the fact?

They’ll be using either CDDB or Freedb, both or which generate a unique DiscID for each CD based on number of tracks and track length. iTunes or whatever app queries the online database for that ID.

How are CDs entered into these databases? Like Wikipedia, really: the public submit them. If you look at a long series of CDs by a single artist, for instance, you’ll notice differences in details, content, and who they consider the artist to be in some cases. For instance I have about 30 CDs of The Goon Show; the Artist is variously listed as The Goons, Goons, The Goon Show, or Goon Show, presumably depending on the whim of whoever submitted it.

Some how the information got into a database. Someone keyed the information in at some point in time. More than likely what happened is that someone who bought, or otherwise obtained a copy of the CD, put it into mp3 format, or otherwise scanned the music to thier favorite digital music format. In so doing, Itunes, Musicmatch, or what-ever they used, uploaded the album, title, artist, and track information into its own database, which in-turn was uploade to a bigger database at some point in time.

I use musicmatch, and musicmatch, connects with its server to find out album information, and if it can’t find the information, it ques me to provide that information.

I had friends in the local music industry at one time, and they were a little chaffed that I would make mp3’s of their music, so I can listen to it when I want to. They too where even more chaffed that thier music from the early 90’s was on CDDB (CD Database.) Oh well suck it up, they all have families now, and wouldn’t want to wear spandex even if they could.

Yes, CDDB is user created. I’ve gone in there and corrected a couple things myself.

CDDB still doesn’t get all of the cd’s though. This spring I wanted my cd’s on the hard drive at a different sample rate, so I had to redo time from scratch. I had about 6 that wouldnn’t recognise and had to enter data. Years ago there would have been maybe forty in the collection that didn’t have entries. I entred all those manualy and sent it to the data base at the time. I think it’s as good as it will get though. some percentage isn’t going to work in the end.

As others have mentioned, this goes way back before iTunes. Almost ever since you could pop a music CD in your computer’s CD-ROM drive, there has been the capability to look up the information on the internet and display it for you.

I remember once having a chuckle over the results, when I put in a CD by Peter, Paul and Mary. The software apparently saw the comma after “Peter” and assumed that was a last name, so the artist was shown as “Paul and Mary Peter.”

iTunes in particular seems to use this database:

(see here: Mac - Official Apple Support )

There is also CD Text which just includes the information right on the cd. This is the system some home and auto cd players use to display song information.

It is hard to believe such a thing was never concieved with the original red book specification of CD’s and had to wait until 1996! It goes to show what a truely outdated concept CDs really are. They just produced a digital version of analogue formats without grasping the very basic informational advantages of digital media.

I do not know if Itunes uses this to find cd information, but it will rip CDs in CD Text format.

… which is the commercial name for the original CDDB, as noted in the Wiki article I linked.

Yes, the original Redbook format only knows the number of tracks, timings, and an pointer so that it can quickly seek them. No meta-data whatsoever. So to find a CD in the database, the match is done against #tracks and their timings.

I think that CDDB/Gracenote has become so pervasive that some record companies now provide them with the information about their CDs as soon as they are released, to ensure that the information there is correct.

I listen to enough obscure music that occasionally I have to be the one to submit the data to gracenote/cddb. I’m careful not to include any mistakes, but it’s true that I occasionally have to correct data that my iTunes has downloaded. Know what I hate? when different people have submitted data for different discs in a multi-disk set, with different formats for author or composer or genre or whatever. Hate that.

The band method book that I teach beginners with includes CD’s for each instrument. The first year we used this book, a student came back saying she put her disc in her computer and the songs were all wrong. It seems that the flute disc for this particular book was linked to the song titles and artwork for the movie 8 Mile. Not only was the track list wrong, but it was for a very un-kid-friendly sort of album.

Supposedly, the book publisher was very upset about this.

My son uses freedb via pcdj to rip CDs into his computer based DJ system. I’m always surprised that the “pre radio release” CD subscription service CDs he gets are already cataloged. I have also noticed though that some old and obscure cds titles sometimes come up misidentified.

and homemade CDs can come up with anything. He tried to rip a song back into the system after burning it on to a CD from itunes and it showed up as some old polka music.