Okay so I've had a bit of a headache with this one. For some reason Mp3Tag metadata isn't displaying correctly in File Explorer.
Some of it seems to work (Title, Artist, Year, Genre) but most of it doesn't seem to show at all. I've had to manually enter the data in File Explorer for most of the fields (on top of Mp3Tag metadata) which is tedious but manageable.
Here's the issue, copyright metadata isn't editable in File Explorer and it's one of the fields which chooses not to display/update. Any suggestions? I'm about ready to pull my teeth out.
That the copyright tag is not editable indicates that Windows Explorer just doesn't support reading or writing that tag to MP4 files. So if it's the requirement to have this available in Explorer you are probably out of luck (you can try bugging Microsoft about this of course). But if the goal is to have the copyright tag in the file you can use Mp3Tag to write that.
Somehow I doubt bugging Microsoft will prove fruitful in resolving this issue. It's possible to write copyright metadata to an Mp4 using Mp3tag, it just doesn't display in the File Explorer copyright field.
I believe that preventing copyright metadata editing within File Explorer is to protect copyright for files. There must be some way to add inherent copyright metadata to an Mp4 file otherwise why have that field in the first place?
The field is filled by MP3tag as this is covered by the standard for mp4 tags.
The problem we have here: The Window Explorer (a file managing program) does not read this field but prefers to take the information from a proprietary xml-solution.
So you see a genuine third party program display problem.