#!/usr/bin/env zsh
# YES_ZSH
# NO_BASH
# NO_DASH

cutv() { ### @-
    [ $# -le 4 ] || { printf "%s\n" "$0: too many arguments" >&2; return 1; }
    local nel="${1?missing length parameter}"
    local f="${2?missing file parameter}"
    local g="cut."${${f##*/}%.*}".mp4"
    ffmpeg -hide_banner -i "$f" 2>&1 \
      | grep Duration \
      | grep -Eo '[0-9][0-9]:[0-9][0-9]:[0-9][0-9].[0-9][0-9]' | awk -F: '{print (($1*60+$2)*60+$3)+$4/100}' | read len
    [[ "$len" -gt 0 ]] || return 1
    echo "$g"
    ffmpeg \
      -hide_banner -loglevel warning -stats -stats_period 5 \
      -i "$f" -ss "$(((nel<len)*(len-nel)))" \
      -sn -dn -metadata = -map_chapters -1 -movflags +faststart \
      -ar 44100 -acodec libfdk_aac -b:a 256k -cutoff 20000 -af alimiter=level_in=2.5:level_out=0.9 \
      -maxrate 7680k -bufsize 9600k -vcodec libx264 -preset medium -crf 21 -vf scale=1280:720 \
      -threads 2 -y "$g" || return 1
    # -maxrate 7680k -bufsize 9600k -vcodec libx264 -preset medium -crf 21 -vf scale=1280:720
    # -maxrate 9600k -bufsize 12000k -vcodec libx264 -preset medium -crf 22 -vf scale=1280:720
}

[ "${SOURCING:-0}" -gt 0 ] || cutv "$@"