Cast Metadata - How to Handle Source Discrepancies

When PLEX grabs/assembles metadata from its various agents/sources, it is ultimately at the mercy of those sources as far as ensuring accuracy & consistency. But how can a PLEX user make corrections when the metadata itself is incorrect or inconsistent? I’ve come across this in particular with some foreign films, in which the titles and/or cast members’ names have – and sometimes don’t have – diacritics.

• Case in point: I have many films in my library featuring Japanese actor Toshiro Mifune. They all show up (the Kurosawa, Zatoichi & other films) when I click on his icon in the Cast lineup. In those film entries his name is spelled “Toshirō Mifune” with the diacritic on the second “o” of his first name.

But I recently added a movie in which his name is written without the diacritic, just “Toshiro Mifune.” When I click on his icon in that movie, the only Mifune title that shows up is that one movie.

According to the cast member link to his photo, it’s two different actors. The one with the diacritic (& all his movies) shows: actor=1296. But the newer one (Samurai Rebellion from 1967), shows: actor=91566.

Is there any way I can correct this? Manually add his name correctly spelled, along with all the other cast members, to the metadata myself using MKVToolNix? If I do that, will his & the other cast members’ additional movies show up properly when I click on them?

I believe I did a similar thing several years ago on an .mp4 movie, manually editing the metadata using kid3. As I recall, however, the corrections I made were exclusive to that movie only. When I brought up that movie in PMS, there were no pictures accompanying any of the cast, and neither did clicking on them take me to any of their other movies in my library.

Any suggestions/insight would be appreciated. TIA.

Movie metadata in plex come mainly from 2 sources:
IMDb.com and TheMovieDB.org
I’d start by comparing cast info of these 2 websites.
They both allow users to contribute corrections.

But before you do this, verify that the wrong actor is not supplied by your video file.
mp4/m4v files can have embedded metadata in them with a cast list.
Is the video file in such a container?

no, as I inferred in the fifth paragraph, it’s an MKV container. no metadata at all, except what I added, i.e., Title of Movie and Year.

Generally, it appears to me that PLEX grabs movie summary/cast info from IMDB, but TV info from thetvdb. So I infer from your reply that I correspond with IMDB. Although I have to say, I’ve tried more than once in the past to get IMDB to correct information, e.g., summaries, plot lines, etc., and they’ve been totally incompetent and/or unresponsive; as if there are a bunch of knuckleheads in charge. So based on those past experiences I probably won’t bother contacting them at all in regard to this issue.

but thank you Sir Moderator for your reply.