How to Convert MIDI to MP3 in Python – A Quick Overview

To convert MIDI to MP3 in Python, two great ways is using the pydub and fluidsynth libraries:

• pydub is a high-level audio library that makes it easy to work with audio files.
• fluidsynth is a software synthesizer for generating audio from MIDI.

Here are three easy steps to convert MIDI to MP3 in Python:

🎵 Step 1: Install the pydub and fluidsynth libraries:

pip install pydub

You also need to install fluidsynth (see below, keep reading this article). The installation process for fluidsynth varies by operating system. For example, on Ubuntu, you can install it via apt:

sudo apt-get install fluidsynth

🎵 Step 2: Download a SoundFont file.

SoundFont files contain samples of musical instruments, and are required by fluidsynth to generate audio from MIDI. A popular free SoundFont is GeneralUser GS, which can be downloaded from the schristiancollins website.

🎵 Step 3: Convert MIDI to MP3.

Use the following Python code to convert a MIDI file to MP3:

import os
from pydub import AudioSegment

def midi_to_mp3(midi_file, soundfont, mp3_file):
    # Convert MIDI to WAV using fluidsynth
    wav_file = mp3_file.replace('.mp3', '.wav')
    os.system(f'fluidsynth -ni {soundfont} {midi_file} -F {wav_file} -r 44100')

    # Convert WAV to MP3 using pydub
    audio = AudioSegment.from_wav(wav_file)
    audio.export(mp3_file, format='mp3')

    # Remove temporary WAV file
    os.remove(wav_file)

# Example usage:
midi_file = 'input.mid'
soundfont = 'path/to/GeneralUser GS.sf2'
mp3_file = 'output.mp3'
midi_to_mp3(midi_file, soundfont, mp3_file)

Replace 'input.mid', 'path/to/GeneralUser GS.sf2', and 'output.mp3' with the appropriate file paths. This script will convert the specified MIDI file to MP3 using the specified SoundFont.

Let’s explore some background information and alternatives next. 👇

🎵 Understanding Midi to MP3 Conversion

MIDI (Musical Instrument Digital Interface) files are useful for creating and editing music notes, but they are not a conventional audio format like MP3.

• 🎼 MIDI files store musical information as digital data, such as note sequences, instrument choices, and timing instructions. MIDI files are the digital representations of musical compositions and store essential data, such as notes, pitch, and duration. These files play a significant role in music production, education, and research.
• 🎵 In contrast, MP3 files store compressed audio data, typically captured from a live performance or created synthetically.

Converting MIDI files to MP3 files allows you to play music on various devices, share them easily, and store them in a more accessible format. Plus, MP3 files are typically smaller in size compared to MIDI files, making them more suitable for distribution.

When converting from MIDI to MP3, your computer uses a software synthesizer to generate audio based on the MIDI data and then compress it into an MP3 file.

To perform this conversion using Python, you can utilize libraries such as midi2audio and FluidSynth synthesizer to process MIDI files, generate audio, and eventually save it in a desired format, like MP3. The midi2audio library provides a convenient command-line interface for fast conversions and batch processing.

💡 Note: There’s an essential difference in how MIDI and MP3 files store and represent audio data. While MIDI files provide instructions for recreating the music, MP3 files directly store the audio data, compressed for efficient storage and playback. This distinction shapes the conversion process, which requires synthesizing and compressing audio data from the digital instructions contained in the MIDI file.

Introduction to FluidSynth

FluidSynth Overview

FluidSynth is a powerful and easy-to-use software synthesizer that allows you to convert MIDI files into audio format with high-quality output. It is an open-source project and can be easily integrated into various applications, including Python projects, to generate music by processing MIDI events. With FluidSynth, you can load SoundFont files (usually with the extension .SF2) to define instruments and customize the sound generation process.

As a Python developer, you can leverage FluidSynth to add audio processing capabilities to your projects. By using a simple Python interface, you can create everything from command-line applications to more complex, GUI-based solutions. Example:

FluidSynth().midi_to_audio('input.mid', 'output.wav')

FluidSynth Synthesizer

The core of FluidSynth is its software synthesizer, which works similarly to a MIDI synthesizer. You load patches and set parameters, and then send NOTEON and NOTEOFF events to play notes. This allows you to create realistic audio output, mimicking the sound of a live performance or an electronic instrument.

To get started with FluidSynth in Python, consider using the midi2audio package, which provides an easy-to-use interface to FluidSynth. With midi2audio, you can easily convert MIDI files into audio format, or even play MIDI files directly, through a simple yet powerful API.

In your Python code, you’ll import FluidSynth and midi2audio, then load a SoundFont file to define your instrument. Once that’s done, you can send MIDI events to the synthesizer and either play the generated audio immediately or save it to a file for later playback.

💡 Resources: FluidSynth documentation and the midi2audio GitHub repository.

Installing Necessary Packages

Package Installation

To get started with converting MIDI to MP3 files in Python, you’ll need to install a few essential packages. First, you will need the midi2audio package. You can install it using pip by running the following command in your terminal or command prompt:

pip install midi2audio

This package will provide you with the necessary tools to easily synthesize MIDI files and convert them to audio formats like MP3 ¹.

Command Line Usage

Once you have installed the midi2audio package, you can start using its command-line interface (CLI). The CLI allows you to perform MIDI to audio conversion tasks quickly without having to manually write a Python script.

Here’s an example of a basic command that converts a MIDI file to an audio file:

midi2audio input.mid output.wav

By default, the output file will be in WAV format. If you want to generate an MP3 file instead, you’ll need to add an extra step. First, install the FFmpeg utility on your system. You can find the installation instructions here.

After installing FFmpeg, you can convert the WAV file to MP3 using the following command:

ffmpeg -i output.wav output.mp3

Now you have successfully converted a MIDI file to MP3 using the command-line tools provided by midi2audio and FFmpeg. With these powerful packages and CLI, you can easily automate and batch process multiple MIDI to MP3 conversions as needed.

Converting Midi to Audio with Midi2Audio

Using Midi2Audio

Midi2Audio is a helpful Python library that simplifies converting MIDI to audio files using the FluidSynth synthesizer. To start using Midi2Audio, first, you need to install it by running pip install midi2audio. Once installed, you can use the library’s Python and command-line interface for synthesizing MIDI files to audio or for just playing them.

Here is an example of how to use Midi2Audio in a Python script:

from midi2audio import FluidSynth

fs = FluidSynth()
fs.midi_to_audio('input.mid', 'output.wav')

In this example, you are configuring a FluidSynth instance and then using the midi_to_audio() method to convert an input MIDI file to an output WAV file.

Batch Processing

Midi2Audio shines when it comes to batch processing, allowing you to convert multiple MIDI files to audio in a single operation. To achieve this, you can simply iterate over a collection of MIDI files and call the midi_to_audio() method for each file.

For example:

from midi2audio import FluidSynth
import os

input_folder = 'midifiles/'
output_folder = 'audiofiles/'

fs = FluidSynth()

for file in os.listdir(input_folder):
    if file.endswith('.mid'):
        input_file = os.path.join(input_folder, file)
        output_file = os.path.join(output_folder, file.replace('.mid', '.wav'))
        fs.midi_to_audio(input_file, output_file)

Here, you are iterating through all the MIDI files in the “midifiles” directory and converting them into WAV audio files within the “audiofiles” directory.

Converting Midi to MP3 using Timidity

TiMidity++ is a powerful tool that can handle various Midi formats and transform them into MP3 files. Here, you’ll find information on the pros and cons of using TiMidity++, followed by a step-by-step process for conversion.

Pros and Cons of Using Timidity

Pros:

• Confidence in output quality: TiMidity++ is widely known for producing high-quality MP3 files from Midi input.
• Cross-platform support: It works seamlessly on Windows, Linux, and macOS, making it accessible to many users.
• Free and open-source: As a free and open-source tool, you don’t need to worry about licensing fees or limitations on its use.

Cons:

• Command-line interface: TiMidity++ has a command-line interface (CLI) which might prove challenging for users unfamiliar with command line tools.
• Less user-friendly: Due to the CLI nature of TiMidity++, it may not be as user-friendly as other software options that have a graphical user interface (GUI).

Step-by-Step Process

1. Install TiMidity++: Download and install TiMidity++ on your system. You can find installation instructions for various platforms on its official website.
2. Obtain your Midi file: Make sure you have the Midi file you’d like to convert to MP3 ready on your computer.
3. Open the command prompt or terminal: In your command prompt or terminal, navigate to the directory containing your Midi file.
4. Run the TiMidity++ command: Execute the following command in your command prompt or terminal, replacing <input.mid> with your Midi file and <output.mp3> with the desired output file name:

timidity <input.mid> -Ow -o - | ffmpeg -i - -acodec libmp3lame -ab 64k <output.mp3>

5. Enjoy your MP3 file: Once the process completes, you will find the converted MP3 file in the same directory as your original Midi file.

That’s it! You have now successfully converted a Midi file to MP3 using TiMidity++.

Additional Tools and Libraries

In this section, we’ll discuss some additional tools and libraries that can help you convert MIDI to MP3 in Python.

SOX and FFMPEG

SOX is a command-line utility that can process, play, and manipulate audio files. It supports various audio formats and can be used alongside other libraries to perform the MIDI to MP3 conversion. To use it in your project, you can either install its command line tool or use it as a Python library.

FFMPEG, on the other hand, is a powerful multimedia tool that can handle audio, video, and images. It also supports numerous formats, so you can use it to convert your MIDI files to MP3 or other formats.

Combine SOX and FFMPEG to effectively process and convert your MIDI files. First, use SOX to convert the MIDI files to an intermediary audio format, such as WAV. Then, utilize FFMPEG to convert the WAV files to MP3. This workflow ensures a smooth, efficient conversion process.

Libsndfile and Channels

Another useful library to consider is libsndfile, which is a C library for reading and writing files containing sampled sound. It supports many common audio formats, including WAV, AIFF, and more.

For Python developers, there is a wrapper library called pysoundfile that makes it easy to use libsndfile in your Python projects. Incorporating libsndfile with other MIDI processing libraries can help you build a complete MIDI to MP3 conversion solution.

When working with audio, you may also encounter different channels in audio files, such as mono, stereo, and surround sound. Libraries such as SOX, FFMPEG, and libsndfile can manage different channel configurations, ensuring your output MP3 files have the desired number of channels and audio quality.

Considerations for Different Operating Systems

When working with Python to convert MIDI to MP3 files, it’s essential to consider the differences and requirements for various operating systems. In this section, we’ll discuss specific considerations for Windows OS, Linux, and Ubuntu 20.04.

Windows OS

On Windows systems, you can use a package like midi2audio to easily convert MIDI files to audio formats like MP3. To install this package, run:

pip install midi2audio

Keep in mind that this package requires FluidSynth to work. You can install FluidSynth for Windows from here, and remember to set up your environment variables to enable the package to find FluidSynth’s libraries and executables. Finally, don’t forget to download a suitable soundfont file, as this will significantly impact the quality of the converted audio.

Linux

For Linux users, the process is similar to Windows. First, install midi2audio using pip:

pip install midi2audio

Next, you’ll need to install FluidSynth through your distribution’s package manager. For example, on Debian-based systems like Ubuntu, execute the following command:

sudo apt-get install fluidsynth

As with Windows, ensure you have a soundfont file that suits your needs. You can find several free soundfont files online. If you’re searching for an alternative command-line tool, consider using SoX – Sound eXchange as it’s versatile and well-suited for scripting and batch processing.

Ubuntu 20.04

In Ubuntu 20.04, the process is, for the most part, the same as other Linux distributions. Since Ubuntu is based on Debian, you can follow the installation process mentioned in the Linux section above.

To reiterate, install midi2audio using pip:

pip install midi2audio

Then, use the package manager to install FluidSynth:

sudo apt-get install fluidsynth

Remember to download your desired soundfont file to achieve the best audio quality for the converted MP3 files.

Frequently Asked Questions

How can I use FluidSynth to convert MIDI to MP3 in Python?

To use FluidSynth for MIDI to MP3 conversion in Python, first, you need to install the midi2audio library, which acts as a wrapper for FluidSynth. You can install this package using pip install midi2audio. Now, use the following code to perform the conversion:

from midi2audio import FluidSynth

fs = FluidSynth()
fs.midi_to_audio('input.mid', 'output.mp3')

For more customization options, check out the midi2audio‘s PyPI page.

What are the best Python libraries for MIDI to MP3 conversion?

The most popular Python libraries for MIDI to MP3 conversion are FluidSynth, which can be used with the midi2audio package, and Timidity++. FluidSynth is known for its ease of use and non-realtime synthesis. Timidity++ usually requires additional setup and configuration, but it is a powerful solution that is often used in Linux-based systems.

How do I extract notes from MIDI files using Python?

To extract notes from MIDI files, you can use the mido library. First, install it via pip install mido. The following code will help you to extract notes from a MIDI file:

import mido

midi_file = mido.MidiFile('input.mid')
for msg in midi_file.play():
    if msg.type == 'note_on':
        print('Note:', msg.note, 'Velocity:', msg.velocity)

Explore the mido documentation for more methods and options.

Can I convert MIDI to MP3 using VLC or Audacity with a Python script?

Yes, you can use VLC or Audacity for MIDI to MP3 conversion through a Python script. You can use the subprocess module to execute command-line arguments for both applications. However, these solutions require additional installations and might not be as streamlined as using dedicated Python libraries like FluidSynth.

Are there any free Python tools for MIDI to MP3 conversion?

There are several free Python libraries that offer MIDI to MP3 conversion. Some of the popular options include FluidSynth combined with the midi2audio package, Timidity++, and using subprocess to interact with command-line applications like VLC or Audacity.

How can I read text from MIDI files using Python?

To read text from MIDI files, you can again rely on the mido library. The following code snippet demonstrates how to extract text from a MIDI file:

import mido

midi_file = mido.MidiFile('input.mid')
for track in midi_file.tracks:
    for msg in track:
        if msg.type == 'text':
            print(msg.text)

By using mido, you can access various types of MIDI messages, including text events, and manipulate the MIDI data as needed.

Python offers utilities like Mido to help you analyze and transform MIDI files seamlessly. Using Mido, you can read, write, and edit MIDI files effectively. It enables you to extract valuable information, such as note sequences, instrument details, and timing data.

Mido provides a powerful interface to work with MIDI data. It is well-suited for dealing with MIDI processing-related tasks and can be integrated seamlessly into your Python projects.

💡 Recommended: Creating Audio Files with Mido in Python