What tags are¶
Tags are descriptive data stored with an audio file: a title, artist, album, track number or embedded picture. The audio stream, the file's path and a player's library records are separate things. Understanding that separation makes an unexpected display easier to diagnose.
One recording, several descriptions¶
Imagine a copied file named 07 - Old Label.mp3 whose stored title is
Paper Boats. Those names can disagree without the audio being different.
A player might show the tag title, a filename fallback or its own cached
library information. Check which source it is using before changing every
copy of the file.
OpenTag's tag fields describe the file; changing TITLE does not automatically
rename it. A file-list filename edit or a rename converter changes its path
without automatically changing the title. An export creates another output;
it does not turn the report text into saved tags.
Fields hold values¶
A field name identifies the kind of information. A value is its content.
ARTIST and ALBUMARTIST are different fields, not two spellings of the
same credit. A field can have several values, such as two artists, rather
than one string containing punctuation.
This practice snapshot distinguishes stored metadata from information computed for the current file:
| Kind | Name | Values |
|---|---|---|
| Metadata | TITLE |
["Paper Boats"] |
| Metadata | ARTIST |
["Juniper Vale","Mira Solberg"] |
| Metadata | ALBUM |
["Harbour Lights"] |
| Metadata | TRACK |
["3/8"] |
| Information | _FILENAME_EXT |
["07 - Old Label.mp3"] |
The brackets illustrate lists, not characters to type into the tag panel.
TRACK=3/8 here is one value describing track and total. Two ARTIST values
carry separate credits. A semicolon inside one value remains punctuation
unless an operation explicitly splits it.
Reading a value is not writing it¶
Format strings read fields and calculate text. For the snapshot above:
| Format string | Calculated text |
|---|---|
%title% |
Paper Boats |
%artist% |
Juniper Vale |
$meta_sep(artist,' & ') |
Juniper Vale & Mira Solberg |
%_filename_ext% |
07 - Old Label.mp3 |
$num(%track%,2) - %title% |
03 - Paper Boats |
A bare placeholder reads the first value; $meta_sep intentionally joins
the artist list for this display. Calculating 03 - Paper Boats does not
rename the file. A converter or action has to use that result as a naming
target and be applied before a path changes.
Information placeholders such as %_filename_ext%, %_codec% and
%_bitrate% come from the file or operation. Typing a tag field named
CODEC does not transcode the audio. Use the documented naming targets
when a path change is intended, rather than treating all displayed
information as writable tag fields.
The field name and native storage are different¶
TITLE is a logical name. A mapping connects it to native storage: for
example, ID3v2 TIT2 or an MP4 title item. A filename extension is not a
universal tag format. One MP3 can contain several tag blocks with different
values, and different readers can prioritize them differently.
Tag formats explains those choices. The field reference explains meanings and mappings. A successful text calculation does not prove that every destination format can store multiple values, long Unicode text, artwork or custom fields.
Pending edits and saved files¶
In the tag panel, typing stages edits for the selection. Save tags writes the selected pending changes. Extended tags… can show several values explicitly. Actions and applied converters have their own immediate-write behavior; they do not all wait for Save tags.
A player's old library display does not establish that a save failed, and an updated OpenTag display alone does not establish a completed disk write. Inspect the operation result, read the file back, and check the receiving player's import/cache behavior when displays disagree.
Work on copies while learning. Native-format and source-access limitations still apply; retained backups matter beyond the current desktop undo session.