In audio production, limiting is an essential technique used to maintain the loudness of a track within a certain range. It helps prevent clipping and distortion, while still allowing the audio to sound punchy and dynamic.

One powerful library for audio processing in Python is pydub. It provides an easy-to-use interface for manipulating audio files. In this blog post, we’ll explore how to set up an audio limiter using pydub.

Installing pydub

Before we get started, we need to make sure that pydub is installed on our system. We can easily install it via pip by running the following command:

pip install pydub

Make sure you have the necessary dependencies, such as ffmpeg, installed as well. You can refer to the pydub documentation for more information on the installation process.

Setting Up an Audio Limiter

To set up an audio limiter using pydub, we need to follow a few steps. Let’s walk through them one by one:

1. Importing the necessary libraries

First, let’s start by importing the required libraries for our audio limiter:

from pydub import AudioSegment
from pydub.playback import play
from pydub.utils import ratio_to_db

We import the AudioSegment class from pydub to work with audio files, the play function to play the audio, and the ratio_to_db function to convert ratios to decibels.

2. Loading the audio file

Next, we need to load the audio file we want to apply the limiter to. Assuming our file is named input.wav, we can load it using the AudioSegment class:

audio = AudioSegment.from_wav("input.wav")

3. Applying the limiter

Now, let’s apply the limiter to our audio. We can use the apply_gain_stereo method of the AudioSegment class to set the maximum gain level:

limited_audio = audio.apply_gain_stereo(max_gain=ratio_to_db(0.8))

In this example, we set the maximum gain level to 0.8, which means the audio will be limited to 80% of its original loudness.

4. Exporting the limited audio

Finally, we need to export the limited audio to a file. We can use the export method of the AudioSegment class to save the audio to a new file:

limited_audio.export("output.wav", format="wav")

Now, the limited audio is saved as output.wav.

5. Playing the limited audio

If you want to listen to the limited audio without saving it to a file, you can use the play function from pydub.playback:

play(limited_audio)

This will play the limited audio directly in your default audio player.

Conclusion

In this blog post, we’ve learned how to set up an audio limiter using pydub in Python. We covered the steps of importing the necessary libraries, loading the audio file, applying the limiter, exporting the limited audio, and playing the limited audio. With pydub’s powerful features, you have the flexibility to adjust the loudness of your audio files to achieve the desired dynamic range.