Please show us some example titles how they look currently and how you would like to see it.
Maybe we can find a pattern to remove this composer part at each end of the title.
These are a few examples. All are genuine tracks in my collection without the track and disk numbers. They were formatted from the original CD's using MP3Tag originally in Disk-Track - Title - Artist format.
Tchaikovsky Nutcracker Suite, Op. 71a - Waltz Of The Flowers - Orchestre Symphonique De Montréal, Charles Dutoit & Pyotr Ilyich Tchaikovsky.mp3
Khachaturian Masquerade - Suite - Waltz - Armenian Philharmonic Orchestra, Loris Tjeknavorian & Aram Khachaturian.mp3
Tchaikovsky Swan Lake, Op. 20, Th.12 Act 1 - Waltz - Orchestre Symphonique De Montréal, Charles Dutoit & Pyotr Ilyich Tchaikovsky.mp3
Tchaikovsky Swan Lake, Op. 20, Th.12 Act 2 - No. 10 Scène (Moderato) - Orchestre Symphonique De Montréal, Charles Dutoit & Pyotr Ilyich Tchaikovsky.mp3
Grieg Peer Gynt, Op. 23 - No. 19, Solveig's Song - Mary-Anne Haeggander, San Francisco Symphony, Herbert Blomstedt & Edvard Grieg.mp3
Mozart Ave verum corpus, K.618 - The Choir of King's College, Cambridge, James Vivian, Stephen Cleobury & Wolfgang Amadeus Mozart.mp3
Mozart Serenade in G Major, K. 525 Eine kleine Nachtmusik - II. Romance (Andante) - Wiener Philharmoniker, Karl Böhm & Wolfgang Amadeus Mozart.mp3
You can use the converter or define actions. The converter gives you a preview of the result.
The unique delimiter before the composer at the end seems to be "&".
First I would fill the composer tagfield with the help of the converter Filename->Tag
As format string you wirite:
%dummy% & %composer%
Normally someone would build a new filename from the tags but you did not write whether you have the necessary tags filled.
So you can just cut off the composer from the filename with the converter Filename->Filename.
Old filename pattern: %1 & %2
New filename pattern: %1
I tend to use TITLE - ARTIST - ALBUM - YEAR - TRACK - GENRE - ALBUM ARTEIST - DISCNUMBER tags to formulate the folder/cd and rely on Musicbrains and DISCOGS to fill in the extras.
I have tried the %dummy% & %composer% coding wich only works if the composer comes after the & symbol.
Unfortunately many tracks I have have a / symbol in them. This is easily seen in the fields but not in the track name. I joins the words either side of the field when composing the final name, So instead of being for example Beatles/Tom Jones the file name shows BeatlesTom Jones. I therefore replace the / with an &. Therefore Tom Jones would become the composer which he isn't.
This Works "C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-02 - Tchaikovsky Swan Lake, Op. 20, Th.12 Act 1 - Waltz - Orchestre Symphonique De Montréal, Charles Dutoit & Pyotr Ilyich Tchaikovsky.mp3" ->
composer: Pyotr Ilyich Tchaikovsky
This Works "C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-03 - Khachaturian Masquerade - Suite - Waltz - Armenian Philharmonic Orchestra, Loris Tjeknavorian & Aram Khachaturian.mp3" ->
composer: Aram Khachaturian
This Does Not Work "C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-04 - Delibes Sylvia, Suite - 3. Pizzicati - Gothenburg Symphony Orchestra & Neeme Järvi.mp3" ->
composer: Neeme Järvi
This Does Not Work "C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-05 - J. Strauss II Tritsch-Tratsch-Polka, Op. 214 - Wiener Philharmoniker & Willi Boskovsky.mp3" ->
composer: Willi Boskovsky
As for your suggestion Filename->Filename. I'm not sure I understood it but i took i literally -
Result:
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-02 - Tchaikovsky Swan Lake, Op. 20, Th.12 Act 1 - Waltz - Orchestre Symphonique De Montréal, Charles Dutoit & Pyotr Ilyich Tchaikovsky.mp3" ->
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-02 - Tchaikovsky Swan Lake, Op. 20, Th.12 Act 1 - Waltz - Orchestre Symphonique De Montréal, Charles Dutoit.mp3"
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-03 - Khachaturian Masquerade - Suite - Waltz - Armenian Philharmonic Orchestra, Loris Tjeknavorian & Aram Khachaturian.mp3" ->
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-03 - Khachaturian Masquerade - Suite - Waltz - Armenian Philharmonic Orchestra, Loris Tjeknavorian.mp3"
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-04 - Delibes Sylvia, Suite - 3. Pizzicati - Gothenburg Symphony Orchestra & Neeme Järvi.mp3" ->
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-04 - Delibes Sylvia, Suite - 3. Pizzicati - Gothenburg Symphony Orchestra.mp3"
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-05 - J. Strauss II Tritsch-Tratsch-Polka, Op. 214 - Wiener Philharmoniker & Willi Boskovsky.mp3" ->
"C:\Users\User\Desktop\Various Artists - Classic FM - Waltzing Classics CD1\1-05 - J. Strauss II Tritsch-Tratsch-Polka, Op. 214 - Wiener Philharmoniker.mp3"
As with the first method it relies on the ampersand to delete / move what comes after it.
Its the front end and the back end of the file - if the composer - I want to get rid of. I do like the idea of moving the composer to the composer tag where it belongs but I don't use the composer field n the file name.
It doesn't account for some classical music where it seems to include the world and it's friends in the artist field.
What data do you have in the tag fields?
usually, MP3tag does not care about the filenames as they are something that the OS needs. And the OS wants to have a unique one and does not care about the sensibility of the presented data.
So if you have all the bits an pieces in the tag fields, write new filenames.
In all other cases: MP3tag cannot read and has now understanding that some strings represent an artist and others a composer and so on, so you would have to find a way to filter the files that show the same pattern and contents and then treat them in the corresponding way.
The screen shot above shows Track 1 of a straightforward Tchaikovsky track 1 AFTER going through Music Brains showing the extra tags,
The screen shot above shows Track 2 of a straightforward Tchaikovsky track BEFORE going through Music Brains showing the original tags
The data changed in MP3Tag is shown here
"Tchaikovsky Ballet Suites\1-119 - The Nutcracker Suite, Op. 71a I. Miniature Overture - French National Orchestra, Kiril Kondrashin.mp3" ->
"Tchaikovsky Ballet Suites [Explicit]\1-01 - The Nutcracker Suite, Op. 71a I. Miniature Overture - French National Orchestra, Kiril Kondrashin.mp3"
"Tchaikovsky Ballet Suites [Explicit]\1-2 - The Nutcracker Suite, Op. 71a II. March - French National Orchestra.mp3" ->
"Tchaikovsky Ballet Suites [Explicit]\1-02 - The Nutcracker Suite, Op. 71a II. March - French National Orchestra.mp3"
I would fill the composer field first.
and then you could use an action of the type "Format value" for _FILENAME with
Format string: $replace(%_filename%,%composer%,)
which would remove a string that can be found in the field COMPOSER from the filename ... provided they match.
I see, though, that you sometimes have abbreviated the composer name ... so you would have to cater for that as well somehow.
Ufortunateley different sources of CD and places like Music Brains and Discogs don’t give the same results for the composer.
I’ve spentt this evening sorting out J.S.Bach, J.S. Bach, J. S. Bach, Johann Sebastian Bach and several other variations of Mr Bach’s name 
This is the joy of maintaining a meticulous library!
I would lik to draw your attention to the filter function.
If you simply type in e.g. Beethoven in the filter, you will get all the files that have Beethovensomewhere in the properties, incl. the filename.
You could then select these and set the metadata right - in more or less 1 go, if you set a whole field.
For others, where the filter string is only part of the data you would have to replace all variations sequentially.
But before you start fiddling with the filename, I would really recommend to get the tag data right.
And then you create new filenames from the settled data.
orenkino
Had not thought of using filter to resolve the naming issue. That will go a long way to resolving my problem.
MotleyG
I just wish that recording companies would be consistent in naming. The problem I had was with ONE CD!
Well, all your examples had the ampersand as a separator before the composer and I wrote "seems to be".
I did explain why the ampersand appears but I did appreciate your assistance.