From 42e88e4dc65f6b2ab1d8fa6a1974fc7b795631cc Mon Sep 17 00:00:00 2001
From: Steven Baltakatei Sandoval <baltakatei@gmail.com>
Date: Thu, 11 Apr 2024 16:59:32 +0000
Subject: [PATCH] feat(user/mp4_make480.sh):Use GNU parallel, split into
 functions

---
 user/mp4_make480.sh | 56 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 43 insertions(+), 13 deletions(-)

diff --git a/user/mp4_make480.sh b/user/mp4_make480.sh
index 8fc75ed..abe5120 100644
--- a/user/mp4_make480.sh
+++ b/user/mp4_make480.sh
@@ -1,19 +1,49 @@
 #!/bin/bash
 # Desc: Reëncodes .mp4 videos in a specified directory.
-# Usage: mp4_make480.sh [dir]
+# Usage: mp4_make480.sh [dir in] [dir out]
+# Input: arg1  dir  input dir
+#        arg2  dir  output dir (optional)
 # Output: dir   ./out/
 #         file  ./out/[files]_480.mp4
-# Version: 0.0.1
+# Version: 0.1.0
+# Depends: GNU parallel 20161222, ffmpeg 4.3.6-0
+# Ref/Attrb: [1]: FFmpeg wiki: https://trac.ffmpeg.org/wiki/Scaling
+declare -g dir_in dir_out;
 
-dir_in="$1";
-dir_out="./out";
-if [[ $# -ne 1 ]]; then echo "FATAL:No dir specified." 1>&2; exit 1; fi;
-if [[ ! -d "$dir_in" ]]; then echo "FATAL:Not a dir:$dir_in" 1>&2; exit 1; fi;
-mkdir -p "$dir_out";
-declare -p dir_in dir_out;  # debug
+check_input() {
+    dir_in="$1";
+    if [[ $# -le 0 ]]; then echo "FATAL:Insufficient args:$#" 1>&2; exit 1; fi;
+    if [[ $# -eq 2 ]]; then
+        dir_out="$2";
+    else
+        dir_out="./out_480";
+    fi;
+    export dir_out;
+    if [[ ! -d "$dir_in" ]]; then echo "FATAL:Not a dir:$dir_in" 1>&2; exit 1; fi;
+    mkdir -p "$dir_out";
+    declare -p dir_in dir_out;  # debug
+};
+convert_video() {
+    find "$dir_in" -mindepth 1 -maxdepth 1 -type f -name "*.mp4" | \
+        parallel job_ffmpeg "{}" "$path_out";
+};
+job_ffmpeg() {
+    path_in="$1";
+    path_out="$2";
+    file_in="$(basename "$path_in")";
+    path_out=./"$dir_out"/"${file_in%.mp4}"_480.mp4;
+    opt_scale="scale=-2:480";  # See [1]
+    declare -p path_in path_out file_in dir_out path_out opt_scale;
+    ffmpeg -nostdin -i "$path_in" -vf "$opt_scale" -c:a copy "$path_out" 1>/dev/random 2>&1;
+};
+export -f job_ffmpeg;
 
-while read -r line; do
-    path_out=./"$dir_out"/"${line%.mp4}"_480.mp4;
-    declare -p line path_out;  # debug
-    ffmpeg -nostdin -i "$dir_in" -vf "scale=-2:480" -c:a copy "$path_out";
-done < <(find . -mindepth 1 -maxdepth 1 -type f -name "*.mp4")
+main() {
+    check_input "$@";
+    convert_video;
+};
+
+main "$@";
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+
-- 
2.30.2