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View Full Version : Weird coincidence?




benpatient
Mar 10, 2005, 12:34 PM
So today I was doing a little...questionable recording on my PC. I have a CD that has LOTS of encryption on it to keep it from working in computers (so that I guess it doesn't end up on the internet?) at all.

I want it on my mp3 player and my iTunes library, but I dont' want to re-buy the CD, right? So I have a 10 dollar walkman CD player and a 3 dollar stereo patch cable.

I recorded the entire album as a single track in WAV format on my PC, and then split the tracks in the Nero CD burning software that I have. I just made rough guesses where the tracks changed, and there was a little bit of white space at the start and end of the recording. I then went and put CD_TEXT information on the tracks and the album (because I have a 100-disc CD changer that reads CD_Text, and my PC's burner will write it (which iTunes won't do on my G5).

Well, I put the burned CD with the guess-work track splits in my G5 and it came up with the album info from CDDB!!!

I seriously doubt that everything "matched up" numbers-wise between my hand-done track splitting and the "official" release of this 14-track CD (Which shouldn't be in CDDB at all if you think about it)

The weird thing is, if it somehow read the CD-text, then it also had to get more info from the CDDB, because iTunes knew the genre and release date, etc....stuff I didn't put in the CD_TEXT information.

Interesting/unexpected ability. Can a G5 superdrive read CD-Text info? Most drives cannot, in my experience...especially on computers...



iGary
Mar 10, 2005, 01:09 PM
It gets it from the Internet, to the best of my knowledge.

benpatient
Mar 10, 2005, 03:01 PM
you seem to not understand my question.

iTunes uses the CDDB look-up service to find CD track and album info online. It does this by reading the length (in seconds) of each track, and the ordering of those tracks. This works very well for commercial CDs which have on average 10-12 tracks. The unique combination of track lengths and number of tracks in a particular order act as a sort of identification for the CDDB look-up module, which can then determine the appropriate mp3 tag info and send it to iTunes.

Because of the way this system works, and it's limitations, the smaller the CD and the fewer number of tracks it has to compare against, the more likely it is to come up with an incorrect (or multiple) "diagnosis" on any particular disc.

Burn a single song to an audio CD, and put it back into your machine. iTunes will use CDDB to look up your CD, and it will return multiple entires for commercially-released singles that happen to be exactly the same length as the song you burned. The system is defeated.

Also, if you have a mix CD or a CD that hasn't made it into the CDDB database yet, then you will either get "no match" and iTunes will leave the track names "Track 1" and so on, or it will return a different CD that happens to have the exact same number of tracks of the same length in the same order. The system is defeated.

I did something that should have appeared to the CDDB system as something other than the album it actually was. The only way that iTunes could have gotten what it did from that disc is if it is capable of reading CD-Text. I have never heard of this, and would be surprised if it were true.

The other possibility, although I think it is unlikely, is that I got REALLY lucky in my track splitting placement, and got every track exactly correct, including the starting and ending points of the disc. This seems very unlikely to me.

I was wondering if anyone had any data on iTunes and CD-Text.