#!/bin/bash

CODEC="-c:v libx265 -pix_fmt yuv420p10le"
FORMAT="matroska"
LENGTH=2
HOST=":"

if [ "$#" -eq 0 ]; then
  exit
fi

while [ "$#" -gt 0 ]; do
  case "$1" in
    -h) HOST+=",$2"; shift 2;;
    -o) OUTPUT="$2"; shift 2;;
    -c) CODEC="$2"; shift 2;;
    -a) CODEC+=" $2"; shift 2;;
    -l) LENGTH="$2"; shift 2;;
    -f) FORMAT="$2"; shift 2;;
    -y) OVERWRITE="-y"; shift 1;;

    --host=*) HOST+=",${1#*=}"; shift 1;;
    --output=*) OUTPUT="${1#*=}"; shift 1;;
    --codec=*) CODEC="${1#*=}"; shift 1;;
    --append=*) CODEC+=" ${1#*=}"; shift 1;;
    --length=*) LENGTH="${1#*=}"; shift 1;;
    --format=*) FORMAT="${1#*=}"; shift 1;;
    --host|--output|--length|--codec|--append|--format) echo "$1 requires an argument" >&2; exit 1;;

    -*) echo "invalid option: $1" >&2; exit 1;;
    *) INPUT="$1"; shift 1;;
  esac
done

TMPDIR="$(mktemp -d)"

if [ -z "$OUTPUT" ]; then
  OUTPUT="${INPUT%.*}".mkv
fi

ffmpeg -i "$INPUT" -map 0:v -map 0:a -c copy -f segment -segment_time $LENGTH -segment_format matroska -reset_timestamps 1 "${TMPDIR}/segment-%03d.0"
parallel -j 1 -S "$HOST" --transfer --return "{.}.1" --cleanup --no-notice "ffmpeg -i {} $CODEC -f $FORMAT {.}.1" ::: "${TMPDIR}"/segment-*.0

for i in "${TMPDIR}"/segment-*.1; do
        echo "file $i" >> "${TMPDIR}"/concat.txt
done

ffmpeg -f concat -safe 0 -i "${TMPDIR}"/concat.txt -c copy $OVERWRITE "$OUTPUT"
rm -rf "${TMPDIR}"