ffmpeg ops

ffmpeg-add-subs.sh

#
# Add subtitles from a .srt (i.e. extracted before) to a .mkv file
#

ffmpeg.exe \
  -i video.mkv                   # input 0 = video to use
  -sub_charenc 'UTF-8'           # support for UTF8 on subs
  -f srt                         # subtitle format srt (change to ass when needed)
  -i sub-file1.srt               # input 1 = subs1
  -i sub-file2.srt               # input 2 = subs2
  -map 0                         # use input 0 (video)
  -map 1:0  -map 2:0             # add the input 1 and 2 (subs) to input 0 (video)
  -c:v copy -c:a copy -c:s srt   # just copy the sources
  # Provide metadata/names for the subtitle tracks
  "-metadata:s:s:0" "language=eng" "-metadata:s:s:0" "handler_name=English"
  "-metadata:s:s:1" "language=es"  "-metadata:s:s:1" "handler_name=Spanish"
  out.mkv

ffmpeg-extract-sub.sh

# Extract a subtitle from a .mkv file
#
# -map X:s:Y means (https://trac.ffmpeg.org/wiki/Map)
# * X: Input index
# * s: subitle (v for video, a for audio)
# * Y: Stream index
# 0:s:0 = the 1st subtitle of the 1st stream

ffmpeg.exe -i INPUT_FILE.mkv -map 0:s:0 OUTPUT.srt

# To display 2 subs at the same time (i.e. 2 langs) use
# https://srtmerge.github.io/ to merge 2 .srt files (i.e. JP+EN into one)

ffmpeg-remove-audio-track.sh

# Remove an audio track from a .mkv file
#
# 0:a:1 = the 2nd audio of the 1st stream

ffmpeg.exe -i INPUT_FILE -map 0 -map -0:a:1 -c copy OUTPUT_FILE