supercut

#!/bin/bash
set -euo pipefail #strict mode
# this script takes as arguments
# 1 the file to do a supercut of
# 2 a file of start and end times
#  (one pair per line, seperated by whitespace,
#  arbitrary comments permitted after end)
# 3 output file (out.mkv by default, clobbers)
# the script outputs a file called out.mkv
#  (will clobber existing file of same name)

# note that this script is LOSSY, SLOW, and NOT ESPECIALLY WELL-TESTED

infile="$1"
timefile="$2"
outfile=${3:-out.mkv}
tmpdir="supercut.tmp"

mkdir "$tmpdir"

declare -i i
i=0
while read -r from to comments; do
    ffmpeg -loglevel error -i "$infile" -ss "$from" -to "$to" "$tmpdir"/"$(printf '%08d' $i)""$outfile" < /dev/null #have to pipe dev null into ffmpeg so it doesn't eat stdin, for some reason.
    # encountered unexpected behavior when I tried to use input (fast) ss
    # also encountered unexpected behavior when I tried to use -c:a copy
    #   or lossless video, or almost anything.
    # one must always expect the unexpected.
    i+=1
done < "$timefile"

( cd "$tmpdir" ; vid-cat "$outfile" ; mv "$outfile" .. )

rm -r "$tmpdir"