ISO Files - Subtitle and Audio Language

Hi,

I have around 2.000 ISO images (UHD, BD, DVD) in my Jellyfin library, I use Jellyfin to build and steer the library and to "cast" the ISOs to a Oppo 203 Player.

Thing is, Jellyfin is able to partly detect and extract metadata information from the ISO, but the language of the subtitles and the language of the audio is not shown.

In the Audio dropbox i see the audio streams with the format (e.g. DTS HD-MA 5.1) but not the actual language (e.g. English). Same for the subtitles, the different subtitles are listed in the dropbox for "Subtitles" but all are listed as "Undefined - PGSUB"

I know the info is in the ISO itself, since TMM5 is able to extract it. The NFO generated by TMM5 also contains the information, but apparently Jellyfin is not reading those tags from the NFO anyway.

Apologies if this has been discussed in the past, but the search didn't return any result.

Thanks!