I understand the point regarding synonyms and euphemisms, but for PRODUCER specifically I’m interested in a movie / film producer. I do use PUBLISHER, but I use it for Distributor or Releasing Agent, for instance.
ARTIST passes from Mp3tag to Plex on its own - it doesn’t have to be tucked way inside iTunMOVI. So I don’t use ACTOR. But it seems that Plex adds DIRECTOR from iTunMOVI to the list of ARTISTS that come through directly, in addition to displaying Director properly. It’s not really a problem for me, it’s just an interesting quirk. I was just wondering Plex would do the same thing if I were to use (e.g.) ACTOR instead of ARTIST. After all, a DIRECTOR can in fact be considered an ARTIST but unless the DIRECTOR also plays a cameo role in the film (as Alfred Hitchcock often did), he or she is not usually considered an ACTOR.
@arb - I’m using “Create iTunMOVI” now and it seems that “PUBLISHER” is somehow ending up as “STUDIO”. Is that a function of iTunMOVI”?
No, ACTOR isn’t supported by Plex and the action requires it. Try transferring ARTIST to ACTOR then removing ARTIST to see what happens.
Yeah, I made the action use COPYRIGHT for “studio”. If COPYRIGHT isn’t there, it’ll use TVNETWORK and PUBLISHER to make an equivalent.
I’m sorry @arb, I’m not making my point clearly. I’m perfectly OK with the way Mp3tag and Plex handle ARTIST together - the handoff from Mp3tag to Plex works correctly at least 98 percent of the time. I only wish the Mp3tag → Plex handoff worked as well for other data elements. As of right now (and it’s subject to change), I don’t need to push ARTIST through “Create iTunMOVI” in order to get performers/actors/cast (usw.) from Mp3tag to Plex. I’m just not sure why DIRECTOR ends up in the list of artists on the Plex end of the handoff. That said, the CSV (comma-separated values) used by Mp3tag for ARTISTs work very well so IMO it would be safe as well as consistent if your admittedly excellent Action were to allow commas as delimiters (in addition to and not instead of) the semicolon and various configurations of slashes. (That’s just an observation).
I guess I should mention that the final target client app for me is the Plex app on a ROKU TV. That’s where I see the list of ARTISTs and the “where-used’ functionality appears. I also use the Plex client app that runs on Windows PCs, which provides more editing and control options than the Plex-on-ROKU app, and the Plex-on-ROKU app has a more sophisticated metadata display (but hardly any maintenance) capabilities. So the various different (and I emphasize “different”) Plex client apps are part of the problem when discussing Plex.
Do you (or @arb) happen to know if Plex reads the ©wrt tag? And if not (and I haven’t been able to make it work, so far) does the “Create iTunMOVI” action read the COMPOSE field?
If I pull up the "Customize" > Mp3tag Options > Mapping" table and enter "ID3v2" in the Tag column, "ALBUM" in the Source Column, and "STUDIO" in the Target column (WITHOUT the quotation marks), will that cause Mp3tag to copy the value of ALBUM to STUDIO in the mp4 metadata?
(Off the subject but I’m curious - does “Ohrenkino” - which I think translates literally to “ear movie” - mean “audio recording”?)
I’ve checked Plex on Windows and Roku: you’ve lost me, there’s no artists section visible anywhere in the video libraries, whatever “where-used” is and I’m clueless how to get an ARTIST tag showing up despite it being possible. 
Is it a custom agent for local media, older version of Plex you’re using…?
Otherwise, please show us an image of Extended Tags from an example file that’s having issues with the mix-up and an image of your Mapping from Options. Maybe something’s getting mixed up that way before Plex is involved. I know it doesn’t bother you but it’s interesting.
Yes.
No, I just tried it myself in Plex. Nothing I’ve read online says it works.
It does now! I’ve made another version for you that supports COMPOSER as well as WRITER, with comma-delimiter support:
Create iTunMOVI - Commas.mta (2.2 KB)
I do my best to use up-to-date versions of all software I use, including (especially) Mp3tag. I have been sending Florian a small honorarium after I download each new version.
Below is a snip of my mp3tag screen, it shows what I use each field for and the internal name of the field I’m using. The tag panel shows only a part of iTunMOVI but I’m using your new action to create it
Following is a photograph of my Roku TV running the Plex app and it shows info for one of the mp4 vids in the screen snap above. The arrow keys on the Roku remote control the cursor. The “where used” list pops up for any of the 5 ARTIST “cast and crew” members are selected. if you expand the photo you’ll see that above the “Watch” button it says “Directed by Dudley Director” which is awsome. And now I notice that the label does say “cast and crew” so that means that director is considered an ARTIST so he’s included in the list of artists even though actor/performer ARTISTS go directly from Mp3tag to Plex, and the DIRECTOR goes from Mp3tag to Plex via the iTunMOVI tag (thanks to you). Note that Plex is known for having different apps behaving in different ways, so if your Plex app isn’t running on a Roku TV, it could look different than mine. For whatever it’s worth my test bed mp4 files are snippets from the movie “Dune” so if you’re a Dune fan the artwork might look familiar
Here's the XML that your new Action created - so it picked up the screenwriter from the COMPOSER field but I don't think it made it to the Plex screen
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>studio</key>
<string>Florian Releasing</string>
<key>directors</key>
<array>
<dict>
<key>name</key>
<string>Dudley Director</string>
</dict>
</array>
<key>screenwriters</key>
<array>
<dict>
<key>name</key>
<string>Rex Writer</string>
</dict>
</array>
</dict>
</plist>
As an mp4 user (and not an mp3 user), mapping "Publisher" to "Studio" doesn't work for me. For commercial movies, "STUDIO" refers to the organization that puts the movie "in the can" - that is, creates the movie. "PUBLISHER" is a.k.a. "distribution company" or "releasing company" is the entity that is responsible getting the movie in front of the people who pay (one way or another) to see it. These days many studios do their own distribution, but historically production and distribution were performed by separate legal entities, and especially for films destined for release internationally, multiple PUBLISHERs distribute the same movie. Today, there are sometimes multiple distribution channels in the same country - e.g., theaters vs Netflix vs DVD/blu-ray, etc. So: is there any way to stop "Create iTunMOVI.mta" from automatically copying "ID3v2 PUBLISHER" to "ID3v2 STUDIO"?
Alternatively, do you know of a tag that I can use for the movie distributor? Is there a tag named Distributor?
I ran my test again and comma-separated directors work awesome with your updated Action - the two directors I entered both ended up on the screen in the line above Watch - and they were both also present on the Cast & Crew Line. And that’s not all - the WRITER ended up in the cast & crew as well - I’m guessing I forgot to save the XML when I tested it before. Woo hoo!!!
I also decided to bite the bullet and open up your “Create iTunMOVI.mta” Action file in Notepad and I guess I could probably find and delete the PUBLISHER → STUDIO part myself but I’m not sure I’m up to messing with your work without shooting myself in the foot
It is not recommended at all to open (and edit) an action outside the MP3tag action editor. Too many things could go wrong.
Riiight, I get now what you mean about ARTIST and DIRECTOR combining… that section combines all known credits. It’s very consistent over all the apps. 
There is no official "ID3v2 STUDIO", you’re referring to the “studio” section of ITUNMOVI which is a completely different type of data. Delete your mapping of PUBLISHER → STUDIO and we’ll go over options.
I ultimately use COPYRIGHT which combines several appropriate fields. If you’re not keen on that, make a custom one called STUDIO or DISTRIBUTOR. Your call. Either way means you can free up PUBLISHER from being remapped.
That… is a fair point and I apologise as I’m used to editing Actions with Notepad as I know the syntax. And it makes better sense teaching you how to edit the action for your future use.
I’d suggest using Actions → Actions → Double-click “Create iTunMOVI - Commas” and you’ll see this:
That 5th line down inserts tags into the “studio” section. Replace it with this and change copyright to whatever custom tag you want to use then hit OK → OK → Close:
%mp3tagfix%[\t\t<key>studio</key>$replace($char(13)$char(10)\t\t<string>$meta_sep(copyright,',' ),/,',' ,; ,',' ,;,',' )</string>$char(13)$char(10)]
Don't bother with Notepad.
...but if you’re feeling bold, in this instance it’s easy-ish to edit from Notepad. I’ll just point out the differences though being the line needs the 1= at the front and it uses \t for a Tab character. That’s two of the things that can go wrong 
You can also easily rename the Action from Action groups or from the file itself in the actions folder if you want.
No worries, I don’t want to ever edit “Create iTunMOVI.mta” at all. I learned early on the pitfalls of messing with code written by someone else, especially in a language with which I’m not familiar. I was just reading the code, but it’s interesting to know that an action editor exists.
I can replace line 5 following your instructions but to be perfectly honest I don’t have a clue as to what the modification is accomplishing, which is precisely why I’m not comfortable modifying code written by others. I don’t know what a “custom tag” is or how a custom tag works with regard to Mp3tag and Plex, etc. I know there’s some Mp3tag documentation and I suppose I should to dig into it but I don’t really know where to start. Maybe I should quit and be happy with what I have. I’ve been using “Album” for “Studio” for some time now, and maybe that’s good enough. Thanks very much for your help, it’s deeply appreciated.
That's totally fine 
It would’ve been to use just the COPYRIGHT tag for the “studio” part of ITUNMOVI. I’ll make this my last input then as the topic’s went on long enough and a solution’s been found.
Please just give this a try as it’s worth it. To make a custom tag, use Extended Tags, click the little star icon to “Add field…” and type its name into Field. While it won’t get seen by Plex or any other software, Mp3Tag will see it no problem and it can be used in Actions or whatever way you want to store and manipulate your data:
I’d strongly advise against using ALBUM as a work-around as Plex uses it for Collections which is really useful for viewing different videos from your libraries put together, like all the Star Wars films, the Star Wars TV shows, everything Star Wars… it’s better functionality for you to use properly.
So here’s one last treat:
Create iTunMOVI - CamdenTommy.mta (2.1 KB)
This will use your new STUDIO tag instead of TVNETWORK, PUBLISHER or COPYRIGHT for the “studio” section of your ITUNMOVI. Use it, don’t use it, not fussed cause you’ve got something working for you. 
And I’m glad it’s working for you finally! Truthfully, reading your topics from over the years helped me look into the problems towards developing this solution (and towards a lot of stuff in the TMDB web source) so thanks to you too 
@arb- I do understand and appreciate your position, but I populated the ALBUM tag with studio names precisely BECAUSE I want Plex to organize my library by STUDIO, so I’m very happy with the way it works. I’ve worked out my own scheme for series within studio name, etc. I’ve also saved and will start using your new version of “Create iTunMOVI, and I’m grateful to you for coding it. And yes I think it’s time to close out this discussion. Thanks to you and ohrenkino (“sound track”??) and everyone else who has contributed.
Post Script: I’ve asked Copilot to summarize the 100 entries in this thread. So for my part in closing, I’m posting it here:
Coda: Summary of Findings on MP4 Director/Writer Tagging
After a lot of testing, discussion, and help from the community — especially @arb — I’m happy to report that we now have a workable, repeatable method for getting DIRECTOR and WRITER metadata from Mp3tag into Plex for MP4 files.
The final solution isn’t the one we originally expected, but it does bridge the gap between Mp3tag and Plex in a reliable way. Given how fragmented MP4 tagging has become over the years — with overlapping standards, legacy atoms, vendor‑specific fields, and multiple interpretations of the same concepts — it’s honestly remarkable that any tag editor and any media server can communicate at all. But with some persistence (and a few workarounds for the workarounds), we got there.
Here’s the distilled outcome:
• DIRECTOR and WRITER now populate correctly in Plex when delivered through a properly structured iTunMOVI XML block.
• The XML schema Plex expects is not the same as the MP4 atom names or Mp3tag’s internal field names. Plex uses its own key names (e.g., DIRECTORS, plural), which must be matched exactly.
• arb’s Mp3tag Action (“Create iTunMOVI.mta”) generates XML in the correct Apple‑style plist format, and with a few adjustments, it can automate the process cleanly.
• The concept has been proven: Mp3tag → iTunMOVI XML → Plex works for DIRECTOR and WRITER, and further fields (PRODUCER, COPYRIGHT DATE, etc.) are now testable.
• The remaining open question is identifying the full set of XML key names Plex recognizes. DIRECTORS is confirmed; PRODUCERS, WRITERS, and others appear likely, but need verification. I’ve asked @arb for insight into where these names originate and why they differ from the standard MP4 atom names.
This has been a surprisingly deep dive into the intersection of tagging standards, Plex’s ingestion rules, and Mp3tag’s flexibility — and most of the key insights were already sitting in the community’s posts, just waiting for the right context to make sense.
Thanks to everyone who contributed knowledge, examples, or encouragement along the way. I’ll continue testing additional fields, but for now, the core goal — getting DIRECTOR and WRITER from Mp3tag into Plex (and more besides!) — is achieved.