I have some videos (mp4) with multiple language subtitles that can be read by an iphone. Users can select to view the subtitle and the language from the default iphone button in the video ui. I would like to be able to set a defalut programmatically, so that, for instance, an user can select a language just one time in the main screen and, from then on, all the videos will have that language subtitles on by default. I can't find anything in the official documentation.

I tought about some workarounds like renaming srt files but i don't think it's possible witouht copying all the video files in the user documents dir (not an option).