audio

Vidéo

→ Yt-dlp

# list subs
yt-dlp -F --list-sub https://www.arte.tv/fr/videos/075801-000-A/flee/
# download subs
--write-subs --sub-langs "fr" https://www.arte.tv/fr/videos/075801-000-A/flee/

Resulting vtt files can be merged simply by adding content from one into the other.

Peertube hanlde both vtt and srt.

→ Mkv

ffmpeg -i my-film.mkv -map 0:s:0 ~/my-film.srt

The first number is which input you select (0 is the first and only input in my command), second character is what type of stream you select (s is subtitles, a is audio, v is video), third is which stream you select out of those. So like this: -map input_file_index:stream_type_specifier:stream_index So the code above takes the Movie.mkv, then its subtitle streams, then the first subtitle stream. (counting starts with 0, because it's an index.)