New tags

Hello

I would like to know if its safe to create completely new tag fields?

Right now I use MP3 and FLAC format. Most of tags are used by both formats [and other], but there are some fields "indigenous" to either MP3 or FLAC. So, knowing that I don't use tag that are not mutual. But [for example] I need 3-4 different tag fields for the year [don't ask why]. And to accommodate my needs I'm using of course the YEAR tag and also [for example] PUBLISHER, which in Mp3tag I display using a name like "Year+" [as both the name of the column and the field in tag panel]. And it works; as long as I do not have the need to use the PUBLISHER tag for putting in it the real publishing information

But I was wondering if it is safe to create a new tag field called [for example] YEAR+? The only downside right now that I could think of is that a non-standard tag will not be dispalayed on a LCD panel of a player and maybe some programs will not see it either. But I'm afraid that in time, it would come to my attention, that there is some glitch acting up when dealing with non-standard fields; and as a result my data would be somehow lost or corrupted

Any thoughts on that?

If you need user defined storage places in a media tag, then create and name such tag-fields as you like it, but make sure not to use well-known common standard names, which probably could be overwritten by other applications.
If an application works well behaved, then it will not touch tag-fields by itself, which are not common standard names.
The tag-field names ... "YEAR+" or "YEAR++" or "YEAR+-?+" ...
look rather ugly, but in Mp3tag they seem to be valid ID3 tag-field names.

DD.20150218.1837.CET

Unfortunately it turns out, that my precious Winamp doesn't display other tags than those official [ID3v2, Vorbis, etc.]

So I have to stick to this workaround: create in panel tag a position with Field value of some tag that I don't use [language, publisher, whatever], describe its name as both >>year + / language<< [so that I don't forget what field I am really using], make Winamp display >>language<< [which is my year+]