Reducing Background Audio Noise Using Neural Networks

Daniel Opitz
Daniel Opitz
20 Aug 2023


If you’ve ever tried to record a podcast, an interview, or simply capture some ambient sounds, you’ll know the struggle of dealing with unwanted background noise. Fortunately, neural network models have come a long way and can now help us filter out that unwanted noise from our audio clips. In this article, we will look at how to reduce background noise from audio files using a pre-trained neural network model called arnndn with ffmpeg.


Getting Started

To begin with, we first need to download the necessary neural network model. Execute the following command to clone the repository containing the pre-trained models:

git clone

After downloading the repository, you’re all set to filter the noise from your audio files.

The ffmpeg Command

ffmpeg -i in.mp3 -af "arnndn=m='rnnoise-models/somnolent-hogwash-2018-09-01/sh.rnnn'" out.mp3

Breaking it down:

  1. ffmpeg - The audio and video processing tool.
  2. -i in.mp3 - Specifies the input audio file. Replace in.mp3 with your filename.
  3. -af - Represents audio filters.
  4. “arnndn=m=’rnnoise-models/somnolent-hogwash-2018-09-01/sh.rnnn’“ - The filter in use. arnndn stands for a neural network denoiser and the model (m) is the path to the neural network model we downloaded.
  5. out.mp3 - The output file name after noise reduction.

Automating the Task with PHP

If you have a bunch of .mp3 audio files that you wish to process, the task can be automated using a simple PHP script:

Filename: convert.php


foreach (glob('*.mp3') as $filename) {
    echo "File: $filename\n";

            'ffmpeg -i "%s" -af "arnndn=m=\'rnnoise-models/somnolent-hogwash-2018-09-01/sh.rnnn\'" "out_%s.mp3"',
            pathinfo($filename, PATHINFO_FILENAME)

This script will search for all files with the .mp3 extension in the current directory.

The exec command runs the ffmpeg command for each audio file to reduce the background noise and then saves the output in an .mp3 format, prefixed with out_.

To run the script, save it to a .php file, place it in the directory with your .mp3 files, and run it using the PHP CLI.

Note, this ffmpeg command also works with .m4p files.

php convert.php


With advancements in neural network models and tools like ffmpeg, it’s easier than ever to enhance the quality of our audio recordings by filtering out unwanted noise. Whether you’re a podcaster, content creator, or simply someone looking to improve their audio files, this method provides an efficient way to achieve clearer audio.

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