It's not clear to me (without rereading zillions of posts here) how this actually works. But the way I want it to work, is to have the subtitles on/off setting remembered on a per-video (file) basis.

When I watch a great Italian film, I want the subtitles every time I play it. But not so for English or (most) French videos. The ideal interface would remember my viewing preference per-video.

Cheers