Tagging

A LP contains tracks, you can see them but if you want to know what is playing you have to look it up on the sleeve.
A CD works the same, you see a track number on the display but again, what is playing can be found on the sleeve.
All this media has to be shelved in some way but no matter what way you choose, there is only one way.

 

Audio files on a computer must be ‘shelved’ to. There is a certain file structure (often Artist > album > tracks) and the files (the individual tracks) have a name.
If you want to play a song, you browse the file structure until you have found it, start to play and probably the player displays the file name so you can see what is playing.
This is using computer audio in the same way as LPs or CDs, a fixed structure and no additional information about the song.

 

A song on a hard disk is a file. A file can be edited and that’s exactly what tagging does.
It add small pieces of information to the song like Album, Artist, Title, Genre, Year, Composer, etc.
Tags enable you to browse and sort  your collection in more than one way
If you move the song to a another device, the player reads the tags and knows at once what the content is.
You can include more information than a file name would allow for, like cover art.
Tagging your songs means you have the song and all the information about this song integrated in one file. This makes the song self documenting.

 

Read more: http://www.id3.org/

Songs, tags and library

Before any player can display your collection, it must know where your audio is located. You tell it which directories should be used and it starts to scan.
It has to know all the files and read all the tags.
This is a rather time consuming process.
To speed up the matter all the information is stored in a library, some kind of database.
Querying the database is much faster than scanning gigabytes of data.

In principle there is a one to one correspondence between the content of the library and the songs on the HD. In practice they might run out of sync. So there are options to reread all the tags from the files and to write all the library information to the corresponding files.

Albums don't exist

If you have used LPs, tapes, CDs for years it takes some time before you realise that there isn’t such thing as an album in computer audio. There are files (the songs) containing a piece of music and the tags.
So what is an album? A couple of songs with exactly the same description in the right tags.
The files might be in the same directory or not, or even on a different hard disk, there isn’t such a thing as an album in computer audio.

 

One day you buy a CD set with all the string quartets by Brahms and by Schumann. Where to store? Under Brahms or under Schumann?

In case of computer audio you don’t have that problem, just tag them different and there you are.

A song is a song is a song is a song.

Yes I know my Getrude Stein
Manipulating the content of a tag affects all the songs having this content. Sounds logical.
 
What happens if the interface allows you to edit an artist or a composer.
You change  Beethoven in to Beethoven, Ludwig van (1780-1829) and all songs with Beethoven as a composer will now display Beethoven, Ludwig van (1780-1829).
Sounds logical as tags operate at song level. This is probably exactly what you intended.

1

This interface has a nice feature, you can rate artist and sort them by rating.
I love the Alban Berg Quartet, lets give them a five star rating.
What happens is that all songs played by the Alban Berg Quartet gets a five star rating and of course overwrite your existing rating.
Sounds logical as tags operate at song level but this is probably not what you intended.

2

You see a genre like crossover and decided you are not in need of it. Let’s clean up this list and delete all those genres with just a couple of songs. This genre is deleted but all the songs having this genre are deleted to!
Sounds logical as tags operate at song level but this is probably not what you intended at all.

3

Well WMP is so kind to prompt you but there is a lot of player software deleting your songs without warning.

 

Manipulating the content of a tag affects all the songs having this content because a song is a song is a song but it might have consequences you won’t appreciate.

 

More on tagging can be found here and there