Introduction

In this tutorial, we will learn how to convert an MP4 video file to an MP3 audio file using the Fluent FFMpeg library in Node.js. The Fluent FFMpeg library is an open-source library that utilizes the FFmpeg library in the background for audio and video conversion tasks. Converting video files to audio files is a common requirement, and this library provides a simple and efficient solution. We will walk through the installation and setup process, step-by-step instructions for extracting the audio and converting the video, and how to save the converted file. Additionally, we will explore handling callback methods, running the FFmpeg script, and testing different audio formats.

1. Installing the Fluent FFMpeg Library

To begin, we need to install the Fluent FFMpeg library as it will be the Core component for our video to audio conversion. The installation process is straightforward, and we will guide You through it.

2. Setting up the Node.js Project

Before we start writing code, we need to set up a Node.js project. We will Create a Package .json file to manage our project dependencies and install the required libraries using NPM.

3. Extracting the File Name

Once our project is set up, we will write code to extract the file name from the command line arguments. This will allow us to specify the video file we want to convert to audio. We will create a function to extract the base name of the file without the extension.

4. Converting the Video to MP3

With the file name extracted, we can now start working on the conversion process. Using the Fluent FFMpeg library, we will invoke a method that will convert the video file to an MP3 audio file. We will explore the flexibility of the library to handle different audio formats.

5. Saving the Converted File

Once the conversion process is complete, we need to save the converted file. We will invoke another method from the Fluent FFMpeg library to automatically create the file at the specified location. We will also implement a callback function to display a message when the conversion is completed.

6. Handling Callback Methods

In addition to the conversion process, the Fluent FFMpeg library provides callback methods for error handling and progress tracking. We will explore how to handle these callbacks and display Relevant messages or progress bars during the conversion.

7. Running the FFmpeg Script

To execute our FFmpeg script, we will write an anonymous function that will automatically run when we execute our Node.js script. This function will handle the command line arguments, invoke the necessary methods from the Fluent FFMpeg library, and display relevant messages Based on the progress of the conversion process.

8. Testing Different Audio Formats

As Mentioned earlier, the Fluent FFMpeg library supports various audio formats. We will run tests on different formats, such as WAV and OGG, to observe the differences in file sizes and conversion time.

9. Conclusion

In this tutorial, we have learned how to convert MP4 video files to MP3 audio files using the Fluent FFMpeg library in Node.js. We have explored the installation process, set up a Node.js project, and implemented the necessary code for audio extraction, conversion, and file saving. Additionally, we have discussed handling callback methods, running the FFmpeg script, and testing different audio formats. By following this tutorial, you will be able to convert video files to audio files effortlessly.

Article

Introduction

Have you ever come across a situation where you need to extract the audio from a video file? Perhaps you only need the audio for a particular project or want to convert a video file to a more portable audio format. In this tutorial, we will explore how to convert MP4 video files to MP3 audio files using the Fluent FFMpeg library in Node.js. By the end of this tutorial, you will have a solid understanding of video to audio conversion and how to handle different audio formats. So, let's get started!

Installing the Fluent FFMpeg Library

Before we dive into the code, we need to install the Fluent FFMpeg library. This library is built on top of the popular FFmpeg library, which is widely used for audio and video processing tasks. To install the Fluent FFMpeg library, we can simply run the following command in our Node.js project:

npm install fluent-ffmpeg

Once the installation is complete, We Are ready to set up our project.

Setting up the Node.js Project

To begin, we need to create a new Node.js project. Open your preferred command line interface and navigate to the directory where you want to create your project. Once you are in the desired directory, run the following command:

npm init -y

This command will create a new package.json file, which will manage our project dependencies. The -y flag will automatically generate the package.json file with default values. Once the command completes, you will see the newly created package.json file in your project directory.

Extracting the File Name

Now that our project is set up, let's move on to writing some code. The first step is to extract the file name of the video we want to convert to audio. To do this, we will create a function that takes the command line arguments and extracts the base name of the file without the extension. This will allow us to conveniently refer to the file name throughout the conversion process.

function extractFileName(filePath) {
  // Logic to extract the base name without the extension
  // ...
  return baseName;
// Usage
const fileName = extractFileName(process.argv[2]);
console.log(`File name: ${fileName}`);

In the above code snippet, the extractFileName function takes the file path as an argument and returns the base name. We achieve this by using STRING manipulation methods like substring and lastIndexOf . Next, we invoke the extractFileName function by passing the Second command line argument ( process.argv[2] ), which represents the file path. Finally, we log the extracted file name to the console for verification.

Converting the Video to MP3

Now that we have the file name extracted, we can move on to the conversion process. Using the Fluent FFMpeg library, we can easily convert the video file to an MP3 audio file. The library provides a convenient toFormat method that allows us to specify the desired output format. In our case, we want to convert the video to an MP3 audio file.

const ffmpeg = require('fluent-ffmpeg');
ffmpeg(process.argv[2])
  .toFormat('mp3')
  .saveToFile(`audio/${fileName}.mp3`)
  .on('end', () => {
    console.log('Conversion completed');
In the above code snippet, we require the fluent-ffmpeg library and invoke it with the video file path as an argument. Next, we chain the toFormat method and specify the output format as mp3. Finally, we use the saveToFile method to save the converted file to a specific location. In this case, we save it under the audio directory with the same file name and an .mp3 extension. We also attach an event listener for the 'end' event to display a message once the conversion is completed.
Saving the Converted File
Now that we have specified the output format and location, we need to handle the saving process. Luckily, the Fluent FFMpeg library takes care of this for us. When we invoke the saveToFile method, it automatically creates the file at the specified location. We can also provide a callback function to be executed when the file saving process is complete.
ffmpeg(process.argv[2])
  .toFormat('mp3')
  .saveToFile(`audio/${fileName}.mp3`, () => {
    console.log('Conversion completed');
In the above code snippet, we simply remove the event listener and pass a callback function as the second argument to the saveToFile method. This callback function will be executed once the conversion and file saving process is complete. Inside the callback function, we log a message to indicate that the conversion is completed.
Handling Callback Methods
Apart from handling the completion of the conversion process, the Fluent FFMpeg library also provides callback methods for error handling and progress tracking. In case of any errors, we can utilize the 'error' event to display the error message. Additionally, we can track the progress of the conversion by utilizing the 'progress' event.
ffmpeg(process.argv[2])
  .toFormat('mp3')
  .saveToFile(`audio/${fileName}.mp3`)
  .on('error', (err) => {
    console.error('An error occurred:', err.message);
  .on('progress', (progress) => {
    console.log(`Conversion progress: ${progress.percent}%`);
  .on('end', () => {
    console.log('Conversion completed');
In the above code snippet, we attach an event listener for the 'error' event and log the error message to the console using console.error. Similarly, we attach an event listener for the 'progress' event and log the progress percentage to the console. We retain the 'end' event listener to log the completion message.
Running the FFmpeg Script
Now that our code is ready, we can execute our Node.js script to convert the video file to an MP3 audio file. Before doing so, we need to provide the path of the video file as a command line argument. Assuming our Node.js script is named index.js and we want to convert a video file named video.mp4, we can run the following command:
node index.js video.mp4
Upon running the command, the script will automatically extract the file name, convert the video file to an MP3 audio file, and save the converted file under the audio directory. The progress and completion messages will be displayed in the console.
Testing Different Audio Formats
One of the advantages of using the Fluent FFMpeg library is its flexibility in handling different audio formats. To test different audio formats, we simply specify the desired format when invoking the toFormat method. For example, to convert a video file to a WAV audio file, we can modify the code as follows:
ffmpeg(process.argv[2])
  .toFormat('wav')
  .saveToFile(`audio/${fileName}.wav`)
  .on('end', () => {
    console.log('Conversion completed');
In the above code snippet, we change the format argument of the toFormat method to 'wav' and update the file extension to .wav in the saveToFile method. We can similarly test other audio formats supported by the Fluent FFMpeg library.
Conclusion
Congratulations! You have successfully learned how to convert MP4 video files to MP3 audio files using the Fluent FFMpeg library in Node.js. Throughout this tutorial, we have covered various aspects of video to audio conversion, including installation and setup, file name extraction, conversion process, file saving, handling callbacks, running the FFmpeg script, and testing different audio formats. By following this tutorial, you now have the knowledge and tools to effortlessly extract audio from video files for your projects. Happy coding!