user/mp4_make480.sh

   1 #!/bin/bash
   2 # Desc: Reëncodes .mp4 videos in a specified directory.
   3 # Usage: mp4_make480.sh [dir in] [dir out]
   4 # Input: arg1  dir  input dir
   5 #        arg2  dir  output dir (optional)
   6 # Output: dir   ./out/
   7 #         file  ./out/[files]_480.mp4
   8 # Version: 0.1.2
   9 # Depends: GNU parallel 20161222, ffmpeg 4.3.6-0
  10 # Ref/Attrb: [1]: FFmpeg wiki: https://trac.ffmpeg.org/wiki/Scaling
  11 declare -g dir_in dir_out;
  12
  13 check_input() {
  14     dir_in="$1";
  15     if [[ $# -le 0 ]]; then echo "FATAL:Insufficient args:$#" 1>&2; exit 1; fi;
  16     if [[ $# -eq 2 ]]; then
  17         dir_out="$2";
  18     else
  19         dir_out="./out_480";
  20     fi;
  21     export dir_out;
  22     if [[ ! -d "$dir_in" ]]; then echo "FATAL:Not a dir:$dir_in" 1>&2; exit 1; fi;
  23     mkdir -p "$dir_out";
  24     declare -p dir_in dir_out;  # debug
  25 };
  26 convert_video() {
  27     find "$dir_in" -mindepth 1 -maxdepth 1 -type f -iname "*.mp4" | \
  28         parallel job_ffmpeg "{}" "$path_out";
  29 };
  30 job_ffmpeg() {
  31     path_in="$1";
  32     path_out="$2";
  33     file_in="$(basename "$path_in")";
  34     path_out=./"$dir_out"/"${file_in%.mp4}"_480.mp4;
  35     opt_scale="scale=-2:480";  # See [1]
  36     declare -p path_in path_out file_in dir_out path_out opt_scale;
  37     ffmpeg -nostdin -i "$path_in" -vf "$opt_scale" "$path_out";
  38 };
  39 export -f job_ffmpeg;
  40
  41 main() {
  42     check_input "$@";
  43     convert_video;
  44 };
  45
  46 main "$@";
  47
  48 # Author: Steven Baltakatei Sandoval
  49 # License: GPLv3+