I can’t tell if this is an issue with the server (asustor) or player (nVidia Shield 2019) and have no way of testing other combos at the moment, but I have a set of MKVs with Russian and Korean audio tracks, the default audio track is set as Korean in all of them, none of the tracks are forced, but Plex is defaulting to the Russian track for all of them no matter what. I’m not seeing any reason this could be happening in my server or player settings.
edit: I’ve since tried in the browser player (rarely use it, forgot it was a thing), and it’s the same.
I don’t know exactly how Plex picks tracks (I’m sure some dev/Ninja will be along to say how), but I think it has very little to do with the “default” flag in your file.
I believe Plex mostly ignores the “default” flag in files. (I think that the specification for the flag is intended to indicate which particular track in a language should be played. That is, if you have 3 English tracks and 3 French tracks, you might have a “default” flag on one English and one French track, to indicate which is the “primary” track for that language.)
Plex instead relies on your account’s language preference to pick the (first? default?) track in your selected language. If no track exists in your preferred language, I think Plex just picks the first in the file.
I only have English tracks myself, so I haven’t had an opportunity to experiment to find out the Plex behavior, but I reasoned out the possible behavior based on how I’d have programmed Plex if I were to do it.
For audio, Plex ignores the default, forced, commentary, etc. flags. It picks the first track that matches the account language settings. If there is no match, then it picks the first track in the file. If you manually choose a track, Plex remembers the choice and uses it the next time you play the same file.
There are additional settings for TV shows.
Edit the show (pencil icon) → Advanced.
There are settings for Preferred audio language, Preferred subtitle language, and Auto-select subtitle mode.
I’ve not used them, but my understanding is the choices override the account settings, and apply to all episodes of the show. So, for example, you could pick Korean as the preferred audio language and Plex would choose the Korean audio track for all episodes.
But only for your account, not for any other accounts (managed users, maybe, but definitely any invited users). If you are making these settings on your server for your users, it’s something to keep in mind.
OK, but there’s nothing set in my account saying my preferred language is Russian over Korean, and I’ve (since) gone through these files and set the Russian track to disabled, but it’s still being prioritized. the only thing that stopped the Russian track from being selected is remuxing the files without the Russian track.
If the two audio tracks in your file do not match your preferred audio track, Plex simply picks the first track it finds, regardless of “default” flag or “disabled” flag or anything. In my experience, the only flag Plex cares about is the “forced” subtitle track flag.
Maybe it looks at the “default” flag if there are multiple tracks in a single language. IIRC, the “default” flag is only intended in the mkv spec to indicate which of multiple identical language tracks to pick over another.
