Currently I have a library mainly in English and I would like to make these films dubbed in Spanish, the problem is that they are in 4k and it is difficult to find releases in Spanish with a quality higher than 720p in the most common free places.
First of all I would like to clarify that I don’t know how the multilanguage system works in Radarr, but, would it be possible to get a spanish version of low quality video, extract its audio and leave it in the same folder so that Jellyfin can choose between multiple video tracks in the player? And is there a way to configure all this automatically in Radarr?
If you’re using torrents, I’d say your best bet would be to try to get into a Spanish private tracker and redownload everything. The ones I’m in have absolutely everything in 4k with dual audio, one being Spanish and the other being the original audio (generally English). I’m aware it might take a while to get into a good one, but once you’re in, you’ll have everything you need.