This script lets you easily load the automatic captions generated by youtube for its videos, either interactively or automatically with preconfigured languages.
It could work for other video providers as well as long as youtube-dl (or yt-dlp, depending on
your setup) populates the JSON it returns to mpv with the subtitles URLs.
This script uses the Lua 5.1 luasocket and luasec modules to download the subtitles directly
from the youtube URL.
Alternatively, if either of these modules is missing, the script downloads the subtitles via yt-dlp.
Note that the yt-dlp solution is a bit slower.
For the time being should not work by default on systems other than Linux due to the method used to cache subs files.
Setting the cache_dir option might help but this is not tested.
Just copy ytsub.lua in your mpv scripts directory.
Hit alt+y to fire up the mpv console selector with the list
of available languages. The subtitles for the selected language are downloaded, added as a track
and the track is selected as primary subtitles.
When hitting alt+shift+y, the script loads the subtitles
for the original language of the video as primary subtitle track and the subtitles for a source
language as secondary subtitle track.
load_autosub_binding: key binding used to select a language and load subtitles. Seempvmanual for the key bindings syntax.autoload_autosub_binding: key binding used to load subtitles with automatic language selection.source_lang: the source language used when loading subtitles automatically. 2-letter code as used by Youtube.cache_dir: path where the subtitles files are cached.
To set a script option, use the --scripts-opts (see man mpv) command-line argument, that can also
be set in mpv.conf.
For instance, use on the command-line:
mpv https://youtu.be/<ytid> --script-opts=ytsub-source_lang=en
And to set it permanently, add in your mpv.conf the line:
script-opts=ytsub-source_lang=en
As two simultaneous subtitles tracks can clutter the video a bit, remember you can set the subtitles font size,
with shift+g and shift+f by default.