If the subtitles are actual subtitles and not dubs, you can extract timestamps from the audio with a model such as whisper + timestamp support. You could then optimize the overlap of timestamps in the subtitle format (e. g. SRT) with the timestamps provided by the model. That would give you a best fit delay, potentially even shifting over time.
Given that you’re in a browser and don’t even have access to the subtitle data, that’s a purely theoretical exercise. While it might be possible to retrieve the subtitles from the site / API the browser is using and then set the delay in the browser component as well, that’d be far too much effort vs. switching to a better playback method.
If the audio is in a different language, all bets are off, there is nothing to sync against. Translations also won’t help, since there are multiple ways to translate any given source material, and the origin and length don’t match up between languages, naturally.
Lumidaub@feddit.org 1 week ago
I get that but I wouldn’t know any such way. There are dedicated subtitle tools that can sync audio and text but those need the files. Failing that you can only do it by ear.
If the subtitle file was downloaded from opensubtitles automatically, there’s also the very real possibility that it’s the wrong file. It might be the correct movie but the subtitles might be synced to a different framerate and there’d be no way for you to know.