initial commit

.gitignore

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+*~
+.DS_Store
+*.pkg.tar.zst
+*.pkg.tar.zst.sig

PKGBUILD

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+# Maintainer: Sebastian Hugentobler <shu@vanwa.ch>
+
+pkgname=music-compiler
+pkgver=0.1.0
+pkgrel=1
+pkgdesc="Transcode a directory tree to mp3."
+arch=("any")
+url="https://code.vanwa.ch"
+license=('MIT')
+depends=("ffmpeg" "bash")
+source=(
+  "music-compiler"
+)
+sha256sums=("7401e88c219ffc27066fbe424a9b6ea44377bec4130b3186e626a7b5714e2f31")
+
+package() {
+  cd "$srcdir/"
+
+  install -Dm 755 music-compiler "$pkgdir/usr/bin/music-compiler"
+}

music-compiler

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+#!/usr/bin/env bash
+set -o errexit
+
+source="./"
+dest=""
+nproc="$(nproc)"
+
+display_help() {
+  echo "Usage: $0 [option...] " >&2
+  echo
+  echo "   -s,   source directory [default: $source]"
+  echo "   -d,   destination directory (the structure of source will be replicated there)"
+  echo "   -n,   number of processes to use [default: $nproc]"
+  echo "   -h,   display this help and exit"
+  echo
+}
+
+parse_args() {
+  while getopts ":hs:d:n:" opt; do
+    case $opt in
+    h)
+      display_help
+      exit 0
+      ;;
+    s)
+      source=$OPTARG/
+      ;;
+    d)
+      dest=$OPTARG/
+      ;;
+    n)
+      nproc=$OPTARG
+      ;;
+    \?)
+      echo "Invalid option: -$OPTARG" >&2
+      display_help
+      exit 1
+      ;;
+    :)
+      echo "Option -$OPTARG requires an argument." >&2
+      display_help
+      exit 1
+      ;;
+    esac
+  done
+}
+
+transcode() {
+  local input="$1"
+  local source="$2"
+  local dest="$3"
+  local tmp_dest="${input/$source/$dest}"
+
+  for ending in %.flac %.m4a; do
+    tmp_dest="${tmp_dest/$ending/.mp3}"
+  done
+  local final_dest="$tmp_dest"
+
+  local parent_dir
+  parent_dir="$(dirname "$final_dest")"
+  [[ -d "$parent_dir" ]] || mkdir -p "$parent_dir"
+
+  ffmpeg -y -i "$input" -c:a libmp3lame -qscale:a 4 "$final_dest"
+}
+export -f transcode
+
+cover_process() {
+  local input="$1"
+  local source="$2"
+  local dest="$3"
+  local final_dest="${input/$source/$dest}"
+
+  local parent_dir
+  parent_dir="$(dirname "$final_dest")"
+  [[ -d "$parent_dir" ]] || mkdir -p "$parent_dir"
+
+  cp "$input" "$final_dest"
+}
+export -f cover_process
+
+parse_args "$@"
+
+SHELL="$(type -p bash) -exv" \
+  find "$source" -type f -name "*.flac" -o -name "*.mp3" -o -name "*.m4a" |
+  parallel -j"$nproc" transcode {} "$source" "$dest"
+
+SHELL=$(type -p bash) \
+  find "$source" -type f -name "cover.jpg" |
+  parallel -j"$nproc" cover_process {} "$source" "$dest"