flac2mp3.sh

#!/bin/bash -eu

if [ "$#" -ne 3 ]; then
  echo "Usage: ./flac2mp3.sh <source_dir> <destination_dir> <bitrate>"
  exit 1
fi

SRC_DIR="$1"
DEST_DIR="$2"
BITRATE="$3"

if ! command -v ffmpeg >/dev/null 2>&1; then
  echo "ffmpeg is not installed. Please install it and try again."
  exit 1
fi

if ! command -v parallel >/dev/null 2>&1; then
  echo "GNU parallel is not installed. Please install it and try again."
  exit 1
fi

export SRC_DIR DEST_DIR BITRATE

convert_flac_to_mp3() {
  src_path="$1"
  rel_path=$(realpath --relative-to="$SRC_DIR" "$src_path")
  dest_path="$DEST_DIR/${rel_path%.flac}.mp3"

  if [ ! -f "$dest_path" ]; then
    mkdir -p "$(dirname "$dest_path")"
    ffmpeg -i "$src_path" -b:a "${BITRATE}k" "$dest_path" 2>/dev/null
    echo "Converted: $src_path -> $dest_path"
  else
    echo "Skipping (already converted): $src_path"
  fi
}

export -f convert_flac_to_mp3

copy_non_flac_files() {
  src_path="$1"
  rel_path=$(realpath --relative-to="$SRC_DIR" "$src_path")
  dest_path="$DEST_DIR/${rel_path%.flac}.mp3"

  if [ ! -f "$dest_path" ]; then
    mkdir -p "$(dirname "$dest_path")"
    cp "$src_path" "$dest_path"
    echo "Copied: $src_path -> $dest_path"
  else
    echo "Skipping (already copied): $src_path"
  fi
}

export -f copy_non_flac_files

total_files=$(find "$SRC_DIR" -type f -iname '*.flac' | wc -l)
echo "Total Flac files to process: $total_files"

find "$SRC_DIR" -type f -iname '*.flac' -print0 | \
  parallel --progress -0 convert_flac_to_mp3

total_files=$(find "$SRC_DIR" -type f -not -iname '*.flac' | wc -l)
echo "Total non-Flac files to process: $total_files"

find "$SRC_DIR" -type f -not -iname '*.flac' -print0 | \
  parallel --progress -0 copy_non_flac_files

echo "Conversion completed."