Sadly I have to edit my 5 star review because since some time in December, this extension no longer works properly. No matter what subtitles you select, the only subtitle that you get is a subscription demand for some subtitle site.
Very unfortunate, it was working perfectly before.

Update Feb 2024: Substital now works again but is subject to the opensubtitles API limit. Not ideal, but it's something.

Excellent add-on!
It does exactly what i need it to do.
I tried another one before this, but that one failed on all fronts.
(+Sub i believe it was called, not sure though)

good

Works well for youtube. I use whisper-ctranslate2 to generate subtitles for Youtube videos and this extension lets me use those subtitles directly in the browser.

works well, only issue is that you can't save synchronization settings so you have to always put it again when next episode starts which is annoying, also option to move the subtitles would be great.

Totally did not understand how the heck this should work. The add-on shows that there's a video running, I click for the subs, nothing happens. Repeated again and again and again, still nothing happened. Basically useless.

When i pick to upload my own subtitles, they always flicker. I want to use downloaded Japanese subtitles but the flickering is too bad. I'll update the review if tell me how to fix this.

It was working well before, but lately the option button at the bottom stopped working, so this is useless to me for now.

Edit: I went back to an earlier version and it's working again

I tried this on a YouTube video. The subtitles appear fine, but the menu doesn't work, so I could not change the background nor the size of the font. I tried it on Edge as well to see if it just clashed with other extensions, but it didn't work there either.

This add-on is really useful. I want it (the idea that adding a subtitle into a streaming that unsupported subtitle like bilibili.tv, etc) and try to find it on the Internet and I thought it did not exist or at least very hard to find. And I was so surprised when I found it. Thank you so much.

perfecto

Not a bad extension, I would've given it 5 stars if it enabled us to move subtitles along the screen.