Convert audio Files using `ffmpeg`, `fzf` and `charmbracelet/gum`

audio_converter.sh

#!/usr/bin/env bash
trap 'exit 1' SIGINT

# Configuration
INDENT="    "
PRESETS_FILE="${HOME}/.config/audio_presets.json"
SYSTEM_PRESETS_DIR="/etc/audio_presets.d"
DEFAULT_PRESETS='{
  "presets": [
    {
      "name": "Standard MP3",
      "extension": "mp3",
      "options": ["-b:a", "192k"]
    },
    {
      "name": "High Quality Opus",
      "extension": "opus",
      "options": ["-b:a", "96k", "-vbr", "on"]
    },
    {
      "name": "CD Quality WAV",
      "extension": "wav",
      "options": ["-ar", "44100", "-ac", "2"]
    },
    {
      "name": "High Quality FLAC",
      "extension": "flac",
      "options": ["-compression_level", "5"]
    },
    {
      "name": "Low Quality AAC",
      "extension": "aac",
      "options": ["-b:a", "128k"]
    },
    {
      "name": "Podcast Quality OGG",
      "extension": "ogg",
      "options": ["-b:a", "64k"]
    },
    {
      "name": "MP3 to OGG",
      "extension": "ogg",
      "options": ["-qscale:a", "5"]
    },
    {
      "name": "OGG to MP3",
      "extension": "mp3",
      "options": ["-b:a", "192k"]
    },
    {
      "name": "MP3 to FLAC",
      "extension": "flac",
      "options": ["-compression_level", "5"]
    },
    {
      "name": "FLAC to MP3",
      "extension": "mp3",
      "options": ["-b:a", "192k"]
    },
    {
      "name": "AAC to MP3",
      "extension": "mp3",
      "options": ["-b:a", "192k"]
    }
  ]
}'

# Check dependencies
check_deps() {
  local missing=()
  command -v ffmpeg &>/dev/null || missing+=("ffmpeg")
  command -v gum &>/dev/null || missing+=("gum")
  command -v jq &>/dev/null || missing+=("jq")
  command -v fzf &>/dev/null || missing+=("fzf")

  if [ ${#missing[@]} -gt 0 ]; then
    gum style --foreground 196 "${INDENT}Error: Missing dependencies: ${missing[*]}"
    exit 1
  fi
}

# Select an inpuinit_presetst file using fzf
select_input_file() {
  local file
  file=$(find . -type f | fzf --height 40)
  echo "$file"
}

# Initialize or load presets
init_presets() {
  # Ensure user presets file exists
  if [ ! -f "$PRESETS_FILE" ]; then
    mkdir -p "$(dirname "$PRESETS_FILE")"
    echo "$DEFAULT_PRESETS" > "$PRESETS_FILE"
  fi

  # Load user presets (expects structure: { "presets": [ ... ] })
  local user_presets
  user_presets=$(jq -c '.presets' "$PRESETS_FILE")

  # Load system presets if available
  local sys_presets="[]"
  if [ -d "$SYSTEM_PRESETS_DIR" ]; then
    shopt -s nullglob
    json_files=("$SYSTEM_PRESETS_DIR"/*.json)
    shopt -u nullglob
    if [ ${#json_files[@]} -gt 0 ]; then
      sys_presets=$(jq -s 'map(.presets) | add' "${json_files[@]}")
    fi
  fi

  # Combine user and system presets into a stream of preset objects
  presets_data=$(jq -c -n --argjson user "$user_presets" --argjson sys "$sys_presets" '$user + $sys | .[]')
}

# Main conversion function
convert_audio() {
  gum style --bold --foreground 212 "${INDENT}🎵 Audio Conversion Wizard" --border=rounded
  echo

  # Select input file using fzf
  gum style --bold --foreground 212 "${INDENT}Select input audio file:"
  local input_file
  input_file=$(select_input_file)
  [ -f "$input_file" ] || { gum style --foreground 196 "${INDENT}Input file not found!"; exit 1; }

  # Use input file's directory as output destination
  local input_dir
  input_dir=$(dirname "$input_file")
  gum style --bold --foreground 212 "${INDENT}Output directory:"
  gum style --foreground 32 "${INDENT}$input_dir"
  echo

  # Ask if batch conversion is desired
  local batch_mode=false
  if gum confirm "${INDENT}Batch convert all files with the same extension in $input_dir?"; then
    batch_mode=true
  fi

  # Determine input file extension and select files
  local input_ext="${input_file##*.}"
  local files_to_convert=()
  if [ "$batch_mode" = true ]; then
    for f in "$input_dir"/*."$input_ext"; do
      [ -f "$f" ] && files_to_convert+=("$f")
    done
  else
    files_to_convert=("$input_file")
  fi

  # Format selection using presets
  gum style --bold --foreground 212 "${INDENT}Select output format:"
  local format_choice
  format_choice=$(echo -e "$presets_data\n{\"name\":\"Custom Format\",\"extension\":\"\"}" |
    jq -r '.name + " (" + .extension + ")"' |
    gum choose --height 10)
  local preset_name
  preset_name=$(echo "$format_choice" | cut -d'(' -f1 | xargs)
  local new_extension
  new_extension=$(echo "$format_choice" | grep -o '(.*)' | tr -d '() ')
  local ffmpeg_opts=()

  if [ "$preset_name" != "Custom Format" ]; then
    local preset_opts
    preset_opts=$(echo "$presets_data" |
      jq -r "select(.name == \"$preset_name\") | .options[]" )
    for opt in $preset_opts; do
      ffmpeg_opts+=("$opt")
    done
  else
    gum style --bold --foreground 212 "${INDENT}Enter custom file extension:"
    new_extension=$(gum input --placeholder "ext")
  fi

  # Additional ffmpeg options
  if gum confirm "${INDENT}Add extra ffmpeg options?"; then
    gum style --bold --foreground 212 "${INDENT}Enter extra options (space-separated):"
    local extra_opts
    extra_opts=$(gum input)
    for opt in $extra_opts; do
      ffmpeg_opts+=("$opt")
    done
  fi

  # Conversion summary
  gum style --foreground 212 "${INDENT}Conversion Summary:"
  gum format -- "${INDENT}| Files to convert: ${#files_to_convert[@]} file(s)
${INDENT}| Output Format: $(gum style --foreground 32 "$new_extension")
${INDENT}| Options: ${ffmpeg_opts[*]}"
  echo

  if gum confirm "${INDENT}Start conversion?"; then
    for file in "${files_to_convert[@]}"; do
      local base_name
      base_name=$(basename "$file" | sed 's/\(.*\)\..*/\1/')
      local output_path="${input_dir}/${base_name}.${new_extension}"
      local cmd=("ffmpeg" "-i" "$file" "${ffmpeg_opts[@]}" "-y" "$output_path")
      echo "${INDENT}Converting: $file -> $output_path"
      if "${cmd[@]}" 2>&1 | grep -i -v "deprecated"; then
        gum style --bold --foreground 46 "${INDENT}✅ Converted: $file"
      else
        gum style --bold --foreground 196 "${INDENT}❌ Failed: $file"
      fi
    done
  else
    gum style --italic --foreground 240 "${INDENT}Conversion canceled"
    exit 0
  fi
}

# Main execution
check_deps
init_presets
convert_audio