Automatic subtitle selection improvements

[JeWe37]

Feature description

It would make sense to automatically select subtitles for videos based on user preferences.

Examples

For instance a user, that only knows English and German, will want English or German non-forced subtitles if they are watching a Spanish show. Similarly, forced subtitles should always be automatically selected if their language matches the audio language and the user knows that language. Technically speaking default subtitles should always be turned on, but I find the tagging for those to be generally too inconsistent as to be worth considering. If two subtitles are of the same preference, some ranking should be done, perhaps based on the subtitle codec, preferring e.g. typically higher quality .ass subtitles. For accessibility, the user should probably be able to choose whether to prefer CC/SDH or non-CC/SDH subs.

References

For an approach for how to do the sorting, see for instance jellyfin/jellyfin#11072.

[zoriya]

There is already an option for this:

Do you want improvements over this option? Right now, there is no CC/SDH special handling.

Forced subtitles are not automatically enabled when you select the corresponding audio, it could make a nice addition.

[JeWe37]

Ah, I missed that one. Then indeed, let's change this to "Automatic subtitle selection improvements". Most of the ideas, SDH, handling multiple known languages, forced subtitle handling, as well as only activating subtitles for unknown languages still apply.