I managed to create the subtitle file, using different language with one single FFMPEG command:
ffmpeg -y -loglevel "repeat+info" -i "file:Intervista.mp4" -i "file:Intervista_fr.srt" -i "file:Intervista_en.srt" -i "file:Intervista_it.srt" -c copy -map 0 -dn -map "-0:s" -map "-0:d" -map "1:0" "-metadata:s:s:0" "language=FR" "-metadata:s:s:0" "handler_name=French" "-metadata:s:s:0" "title=French" -map "2:0" "-metadata:s:s:1" "language=ENG" "-metadata:s:s:1" "handler_name=English" "-metadata:s:s:1" "title=English" -map "3:0" "-metadata:s:s:2" "language=ITA" "-metadata:s:s:2" "handler_name=Italiano" "-metadata:s:s:2" "title=Italiano" "file:output.mp4" For some reason, the default subtitles shown when I start the video is English, which is the one in the middle. How do I set the default subtitle file to Italian?
