How to Use FFmpeg Bass and Treble Filters

Adjusting the equalization of an audio file is a common task that can be easily achieved using FFmpeg’s built-in command-line tools. This article provides a quick and straightforward guide on how to use the bass and treble audio filters in FFmpeg to boost or cut low and high frequencies, complete with practical command examples.

Understanding the Bass and Treble Filters

FFmpeg provides two specific audio filters, bass and treble, which act as shelving equalizers. They allow you to boost (increase volume) or cut (decrease volume) frequencies below or above a specific limit.

Both filters accept three primary parameters: * g (gain): The amount of boost or cut in decibels (dB). Positive numbers boost the frequency, while negative numbers cut it. * f (frequency): The central or shelf frequency in Hz. * w (width): The filter’s bandwidth or slope (often left at its default value of 0.5).

How to Use the Bass Filter

The bass filter targets low-frequency sounds (typically below 300 Hz). By default, it operates at a center frequency of 100 Hz.

To boost the bass by 8 dB at the default frequency of 100 Hz, use the following command:

ffmpeg -i input.mp3 -af "bass=g=8" output.mp3

To cut the bass by 5 dB at a custom frequency of 150 Hz to reduce muddiness, run:

ffmpeg -i input.mp3 -af "bass=g=-5:f=150" output.mp3

How to Use the Treble Filter

The treble filter targets high-frequency sounds. By default, it operates at a center frequency of 3000 Hz.

To boost the treble by 6 dB to add brightness to a track, use:

ffmpeg -i input.mp3 -af "treble=g=6" output.mp3

To cut harsh high frequencies by 10 dB at a custom frequency of 8000 Hz (8 kHz), use:

ffmpeg -i input.mp3 -af "treble=g=-10:f=8000" output.mp3

Combining Bass and Treble Adjustments

You can apply both filters simultaneously in a single command by chaining them together with a comma inside the audio filter (-af) argument.

To boost both the bass (by 6 dB at 80 Hz) and the treble (by 5 dB at 10,000 Hz) for a classic “smile” EQ curve, run:

ffmpeg -i input.mp3 -af "bass=g=6:f=80,treble=g=5:f=10000" output.mp3