user/mp4_make_small.sh

   1 #!/bin/bash
   2 # Desc: Reëncodes .mp4 videos in a specified directory to reduce size.
   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]_small.mp4
   8 # Version: 0.0.3
   9 # Depends: GNU parallel 20231122, ffmpeg 6.1.1
  10 # Ref/Attrb:
  11 declare -g dir_in dir_out;
  12
  13 check_input() {
  14     dir_in="$1";
  15     if [[ ! -d "$dir_in" ]]; then echo "FATAL:Not a dir:$dir_in" 1>&2; exit 1; fi;
  16     if [[ $# -le 0 ]]; then echo "FATAL:Insufficient args:$#" 1>&2; exit 1; fi;
  17     if [[ $# -eq 2 ]]; then
  18         dir_out="$2";
  19     else
  20         dir_out="${dir_in}/out_small";
  21     fi;
  22     export dir_out;
  23
  24     mkdir -p "$dir_out";
  25     declare -p dir_in dir_out;  # debug
  26 };
  27 convert_video() {
  28     find "$dir_in" -mindepth 1 -maxdepth 1 -type f -iname "*.mp4" | \
  29         parallel -j25% job_ffmpeg "{}" "$path_out";
  30 };
  31 job_ffmpeg() {
  32     path_in="$1";
  33     path_out="$2";
  34     file_in="$(basename "$path_in")";
  35     path_out="${dir_out}/${file_in%.[mM][pP]4}"_small.mp4;
  36
  37     declare -p path_in path_out file_in dir_out path_out;
  38     ffmpeg -nostdin -i "$path_in" -c:v libx264 -preset veryslow -crf 26 -pix_fmt yuv420p "$path_out";
  39 };
  40 export -f job_ffmpeg;
  41
  42 main() {
  43     SECONDS=0;
  44     ti="$(date -Is)";
  45     check_input "$@";
  46     convert_video;
  47     tf="$(date -Is)";
  48     printf "%s\n" "STATUS:Finished in $SECONDS seconds with status $?.";
  49     printf "%s\n%s\n%s\n" "STATUS:Job start and end times:" "$ti" "$f";
  50 };
  51
  52 main "$@";
  53
  54 # Author: Steven Baltakatei Sandoval
  55 # License: GPLv3+