ffmpeg -i Doktor.Suster.2001.1080p.HDTV.x264.AAC-BD4YU.mkv -map 0:s:0 subs.srt :
It sounds like you have a specific video file ( Doktor.Suster.2001.1080p.HDTV.x264.AAC-BD4YU.mkv ) and are looking for a helpful guide—most likely on how to play it, fix issues, or understand its technical details. Doktor.Suster.2001.1080p.HDTV.x264.AAC-BD4YU.mkv
VLC Media Player (free, open-source, plays almost anything). ffmpeg -i Doktor