I'm learning my way around the world of tagging, and I really appreciate Mp3Tag. But I have one question I can't find in the help file.
I see "Filename," "Path," "Tag," and some other columns displayed. What is the function of the "Tag" column, which in my case always shows "FLAC (FLAC)" ? I've studied the list of tags used in Mp3Tag and how they correspond to the tags used in various formats, and can't find a generic "Tag". I notice various options to copy filename to tag, trackname to tag, etc. So what is this for and is it written to the actual music file, or just something used internally by Mp3Tag?
A 'tag' is a separate area of byte characters, containing any data, prepended or appended to the existing music data in the media file.
There exist several types of 'tags':
FLAC, APE, ID3v1, ID3v2.3, ID3v2.4 and some others.
They all have their individual rules and standards, how they are internally structured and stored.
In general a 'tag' contains a list of 'tag-fields', which are 'name=value' pairs.
Some 'Tags' are only designed for a special file type, some can be used with different media file types.
The Mp3tag column "TagRead (TagTypes)" displays the information, what tag-types have been detected by Mp3tag in the current media file, and what tag-type has been currently read by Mp3tag.
Mp3tag's Converters and Actions work with the currently adjusted tag-type.
Regarding MP3 files Mp3tag works with the tag-type which is currently set to be read resp. set to be written. See Mp3tag/Extras/Options/Mpeg.
When working with FLAC files, Mp3tag reads and writes only the FLAC related tag-type named "VorbisComment".
The Tag column is only for informational use. If you right-click in the header of the columns you can get to their configuration and see the actual definition of each column. Then, if you go to this help page you can see an explanation of the variables used. You can also use the columns customization dialog to define new columns and to hide the default ones. Note that any column definition that has a blank "Field:" is not editable. You should see this for the Tag column.
First, you probably need an understanding of the terminology used by Mp3tag. The individual pieces of metadata, like ARTIST and ALBUM and TITLE are called "fields". "Tags" are the collection of fields. Different types of tags use different conventions for storing data.
Certain type of files can (or should) contain only one type of tag. A FLAC file should only contain a FLAC tag. An Mp3 file, on the other hand, can contain more than one type of tag. It can contain an ID3v1 tag and an ID3v2 tag, and possibly also an APE tag. The Tag column attempts to tell you the type(s) of tags found in the file and which one it read. For FLAC files it's generally of little use, although some files will sometimes have an ID3v2 tag. For Mp3 files it can be helpful to know what kind of tags a file contains. You'll also note that for Mp3 files you can designate which tags are read (under File > Options > Tags > Mpeg).
The terminology can be confusing, and you'll often see the term "tag" used to describe the different fields, even in these forums.
Thanks to both of you for your careful replies. Now I understand that "FLAC (FLAC)" entry, which I thought was rather strange. I always use FLAC files so I can hide the Tag column since it doesn't do anything useful for me.