[scbrg]

+1. This is a fantastic feature. I haven't even bothered learning the keybindings (perhaps I should), I just start with --sid1= and --sid2= and it works well enough.

Neither me nor my significant other are native English speakers, but we have different native languages. I'm comfortable enough with English, but like having English subtitles since I have a hard time with some dialects and occasionally just miss a word or two due to noisy audio. My SO likes having subtitles in their native language.

Being able to have multiple subtitles makes it possible for both of us to get the experience we like, at the cost of a little screen real estate. Well worth it.

[ksdnjweusdnkl21]

They are not default keybinds, but like any configuration can be cycled or set at runtime. Actually I don't use the keybindings much directly since my default config usually is fine, but have a remote GUI to configure it when needed.

[exikyut]

Depending on the aspect ratio of the video and playback viewport, you could move the subtitles into the potential black bar underneath.

If there is no black bar, you could get one of those long narrow LCDs off AliExpress, set up the driver, add it as an X display with the right positioning... and then drag the mpv window across that and the TV. Should work. Those little LCDs are just silly expensive though...