$trim() works on the contents of a field, not the fieldname.
$trim() also works only in generating format strings but not matching format strings - for the import of data from files a matching format string is required.
See here for more descriptions of format strings:
esp. the part
" Format strings are used in two ways in Mp3tag, matching format strings and generating format strings.
Matching format strings are used for simple pattern matching of existing strings, e.g., file names to import tags from or lines in a text file that describe tag contents to be imported.
Generating format strings are used to create new strings, e.g., file names when renaming, field contents when formatting tag fields, data when exporting, but also file names for playlists or cover images that are parameterized with tag contents. Generating format strings can be combined with scripting functions."
Modification date is a OS file system function. Usually any time a file is changed for any reason this date reflects the current date and time. This is with or without using mp3tag.
In the options for mp3tag there is a setting that you can check so that this date is not changed when saving from mp3tag. However this means most other software will not find any reason to update.
Since you are seeing the genre update I doubt this is the cause here. I am more inclined to believe that additional characters are being used during the import as has been discussed already.
Clearly if three different player programs are unable to see the updated tag info for any field, there is a mismatch between what is expected and what has been written.
I can very much confirm that both the composer and conductor fields when saved directly from mp3tag are very much visible in MusicBee using mp3, FLAC, and m4a files when tested on my side.
This leads back to something in your environment that is causing the mismatch to occur. Since you are depending on an import from a csv file to harness this external data you will need to comb through that to determine if the error can be found in the naming there.
As an alternative test, use the tag panel in mp3tag to manually type in the Composer and Conductor data and save it. (You may need to add these fields to your panel as I cannot recall if they are there by default). For the test file, can MusicBee now see these changes? If yes the problem is definetly in your csv source data.
//Just some pseudocode during the import to cleanup fieldnames
$fieldname = str_replace('%', '', $import_fieldname);
$fieldname = '%'.trim($fieldname).'%'
Is that not possible in mp3tag, sanitizing a fieldname seems crucial, to me.
@mattiebear I feel with you, if this is what happened in your import, would frustrate me too.
And I'm glad I learned something -- hope you read this and get your imports to work soon.
Field name placeholders for actions. are always lower case and enclosed within percent symbol characters such as %composer% or %conductor% for mp3tag formatting. Reference simply to their names is in all caps such as COMPOSER or CONDUCTOR.
I do not think that there is a rule about the case of a field name.
Here in the forum we try to use a certain style to distinguish between a semantic reference to e.g. a composer, the contents of the field %composer% or the field name COMPOSER.
Some applications require field names to be all capitals if the field names are not identified by tokens but by their real name which is e.g. the case for vorbis comments in flac files.
These field names can adapted with an action of the type "Case conversion" for _FIELDNAME.
For a discussion on the case of field names, please open a new thread.
Please upload it to one of the public and free transfer websites (like WeTransfer.com or swisstransfer.com) and then share the link to your upload here.
As for there being Conductor and Conductors, I did this in error trying to fix the problem myself before asking for help as a reference on another sources said the tag was conductors rather than conductor.
To get usable results, please clear your test songs every time completely from MusicBee and MediaMonkey. Then import your new/updated version.
Otherwise you don't know if the new file was imported and the metadata refreshed or of they are still displayed from the internal database.
