audio_converter.info

Let’s break down what this script does in detail. The script is named audio_converter.sh, authored by GJS (homelab-alpha), and its purpose is to convert audio files in various formats (m4a, mp3, wma) to MP3 format with specific settings for bitrate, sampling rate, and channel configuration.

Here’s a detailed explanation:

Script Metadata link

• Filename: audio_converter.sh
• Author: GJS (homelab-alpha)
• Date: May 18, 2024
• Version: 1.0.1
• Description: This script converts audio files in formats such as m4a, mp3, and wma to MP3 format with a bitrate of 128k, a sampling rate of 44.1kHz, and 2-channel audio.
• Dependencies: avconv, ffmpeg
• RAW Script: audio_converter.sh

Setup link

1. Enable Case-Insensitive Matching:

   shopt -s nocasematch
   

   This allows the script to match file extensions without regard to case (e.g., .MP3 and .mp3 are treated the same).

2. Define the Working Directory:

   working_directory="./mp3_converted"
   

   This sets the directory where the converted MP3 files will be stored.

3. Check and Create the Directory:

   if [ ! -d "$working_directory" ]; then
     echo "Convert directory does not exist: $working_directory"
     mkdir -p "$working_directory"
     echo "Convert directory created: $working_directory"
   fi
   

   This block checks if the specified directory exists. If it doesn’t, it creates the directory.

File Conversion link

4. Loop Through Files in the Current Directory:

   for i in *; do
   

   This loop iterates over each file in the current directory.

5. Case Statement for File Types:

   case $i in
   *.mp3)
   

   This part of the script handles files based on their extensions. Let’s break down each case:

   • MP3 Files:

     avconv -analyzeduration 999999999 -map_metadata 0 -i "$i" -vn -acodec libmp3lame -ac 2 -ab 128k -ar 44100 "$working_directory/$(basename "$i" .mp3).mp3"
     echo "$i converted to MP3"
     

     This converts MP3 files using avconv with specific parameters: 128k bitrate, 44.1kHz sampling rate, and 2 channels. The metadata is preserved, and the output file is saved in the specified directory.

   • M4A Files:

     ffmpeg -i "$i" -n -acodec libmp3lame -ab 128k "$working_directory/$(basename "$i" .m4a).mp3"
     echo "$i converted to MP3"
     

     This converts M4A files using ffmpeg with similar settings. The -n option prevents overwriting existing files.

   • WMA Files:

     avconv -analyzeduration 999999999 -map_metadata 0 -i "$i" -vn -acodec libmp3lame -ac 2 -ab 128k -ar 44100 "$working_directory/$(basename "$i" .wma).mp3"
     echo "$i converted to MP3"
     

     This converts WMA files using avconv with the same parameters as for MP3 files.

   • Unrecognized Files:

     echo "Skipping unrecognized file: $i"
     

     If the file doesn’t match any of the recognized extensions, the script skips it and prints a message.

Cleanup link

6. Disable Case-Insensitive Matching:

   shopt -u nocasematch
   

   This reverts the case-matching setting to its original state.

7. Exit the Script:

   exit 0
   

   This ends the script.

Conclusion link

The audio_converter.sh script is designed to automate the conversion of various audio file formats to MP3 with consistent settings. It ensures the converted files are stored in a designated directory, handles errors gracefully, and avoids overwriting existing files.

This script effectively converts various audio formats to MP3 while maintaining the original directory structure and handling errors gracefully.