Make a portable, lossy copy of your music library. https://elfakyn.com/music/organize-your-library

convert_library.sh

#!/usr/bin/env bash
# Make a portable, lossy copy of your music library. https://elfakyn.com/music/organize-your-library
SOURCE_DIR="/source/music/folder"
DEST_DIR="/destination/music/folder"
JOB_FILE="./conversion_jobs.txt"
ERROR_LOG="./conversion_errors.log"

> "$JOB_FILE"
> "$ERROR_LOG"

declare -a partial_files

convert_flac_to_opus() {
    local file="$1"
    local dest_opus_path="$2"

    partial_files+=("$dest_opus_path")

    if ! opusenc --quiet --vbr --bitrate 256 "$file" "$dest_opus_path" 2>&1 | tee -a "$ERROR_LOG"; then
        # If conversion failed, clean up the partially written file
        rm -f "$dest_opus_path" 2>/dev/null
    fi

    partial_files=("${partial_files[@]/$dest_opus_path}")
}

export -f convert_flac_to_opus
export ERROR_LOG

total_files=$(find "$SOURCE_DIR" -type f | wc -l)

files_processed=0
files_skipped=0
files_copied=0
flac_files_queued=0

trap 'echo -e "\nProcess interrupted. Exiting..."; clean_up_partial_files; kill 0' SIGINT

clean_up_partial_files() {
    echo "Cleaning up partially written files..."
    for file in "${partial_files[@]}"; do
        rm -f "$file"
        echo "Removed partial file: $file"
    done
}

echo -n "Processing files: "

find "$SOURCE_DIR" -type f | while IFS= read -r file; do
    relative_path="${file#$SOURCE_DIR/}"

    dest_path="$DEST_DIR/$relative_path"
    dest_folder=$(dirname "$dest_path")
    mkdir -p "$dest_folder"

    dest_opus_path="${dest_path%.flac}.opus"

    if [ "${file##*.}" == "flac" ]; then
        if [ -f "$dest_opus_path" ] && [ "$dest_opus_path" -nt "$file" ]; then
            # Skip the file if the destination file is newer
            files_skipped=$((files_skipped + 1))
        else
            echo "convert_flac_to_opus \"$file\" \"$dest_opus_path\"" >> "$JOB_FILE"
            flac_files_queued=$((flac_files_queued + 1))
        fi
    else
        # Check for non-FLAC files
        if [ -f "$dest_path" ] && [ "$dest_path" -nt "$file" ]; then
            # Skip the file if the destination file is newer
            files_skipped=$((files_skipped + 1))
        else
            partial_files+=("$dest_path")
            cp "$file" "$dest_path"
            partial_files=("${partial_files[@]/$dest_path}")
            files_copied=$((files_copied + 1))
        fi
    fi

    files_processed=$((files_processed + 1))
    echo -ne "\rProcessing files: $files_processed/$total_files (Copied: $files_copied, Skipped: $files_skipped, FLAC queued: $flac_files_queued)"
done

echo -e "\nDone copying files."
echo "Running conversions in parallel..."

cat "$JOB_FILE" | parallel --progress --eta --bar

# Update m3u and m3u8 playlists to reference .opus files instead of .flac
find "$DEST_DIR" -type f \( -iname "*.m3u" -o -iname "*.m3u8" \) -print0 | while IFS= read -r -d '' playlist; do
  sed -i 's/\.flac/\.opus/g' "$playlist"
  echo "Updated playlist: $playlist"
done