Recursive, "multithreaded" music converter in bash. 1:1 Copies everything that isn't a flac to keep ur box art scans, covers and already lossy files.

flac_to_ogg.sh

#! /usr/bin/env nix-shell
#! nix-shell -i bash -p opusTools

# Set source and target directories
src_dir="/vol/ikea/Media/Music/Ready"
target_dir="/vol/ikea/Media/Music/Essa"

# Number of allowed threads
max_threads=2

# Semaphore function to limit the number of threads
# YES WE HAVE FUCKING SEMAPHORES IN BASH HOLYYYYYYY SHIT
semaphore() {
    while [ $(jobs | wc -l) -ge $max_threads ]; do
        sleep 1
    done
}

# Function to convert FLAC to OGG Opus
convert_flac_to_opus() {
    flac_file="$1"
    ogg_opus_file="${flac_file%.*}.opus"
    opusenc --bitrate 192 "$flac_file" "$ogg_opus_file"
}

# Function to process directories and files
process_directory() {
    local src="$1"
    local dest="$2"

    # Create target directory structure if it doesn't exist
    mkdir -p "$dest"

    # Loop through files and subdirectories
    for file in "$src"/*; do
        if [[ -d "$file" ]]; then
            # If it's a directory, recursively process it
            semaphore
            process_directory "$file" "$dest/$(basename "$file")" &
        elif [[ "${file##*.}" == "flac" ]]; then
            # If it's a FLAC file, convert it to OGG Opus and preserve the directory structure
            semaphore
            convert_flac_to_opus "$file"
            mkdir -p "$dest"
            mv "${file%.*}.opus" "$dest" &
        else
            # If it's not a FLAC file, copy it to the target structure
            semaphore
            cp "$file" "$dest" &
        fi
    done

    # Wait for all background processes to finish
    wait
}

# Run the conversion process
process_directory "$src_dir" "$target_dir"