How to Use the Treble Filter in FFmpeg

This guide explains how to use the treble audio filter in FFmpeg to adjust the high-frequency components of your audio files. You will learn the basic syntax of the filter, its key parameters—including gain, frequency, and width—and practical command-line examples for boosting or cutting treble in your media.

Understanding the Treble Filter

The treble filter in FFmpeg is a high-shelving equalizer. It allows you to boost or attenuate audio frequencies above a specified threshold. This is useful for brightening muddy audio (boosting treble) or reducing harsh high-pitched noises and sibilance (cutting treble).

Treble Filter Parameters

The filter accepts several options, which can be specified as key=value pairs separated by colons:

• g or gain: Sets the audio boost or attenuation in dB. Positive values boost the treble, while negative values reduce it. The default is 0.
• f or frequency: Sets the filter’s central frequency in Hz. Frequencies around and above this limit will be affected by the gain. The default is 3000 Hz.
• w or width: Sets the bandwidth/slope of the filter. The default is 0.5.
• t or width_type: Defines the unit of the width parameter. Options include h (Hz), q (Q-factor), o (octave), and s (slope). The default is o.

Practical Examples

To apply the treble filter, use the audio filter flag (-af or -filter:a) in your FFmpeg command.

1. Boost Treble

To boost the high frequencies by 6 dB using the default frequency threshold of 3000 Hz, run:

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

2. Cut Treble

To reduce harsh high frequencies by 8 dB to make the audio sound warmer, use a negative gain value:

ffmpeg -i input.wav -af "treble=g=-8" output.wav

3. Adjust Target Frequency and Width

To target higher frequencies (such as those above 5000 Hz) with a custom width of 1.0 octave and boost them by 5 dB, define the parameters explicitly:

ffmpeg -i input.mp4 -af "treble=g=5:f=5000:w=1.0" -c:v copy output.mp4

(Note: The -c:v copy option is used here to copy the video stream without re-encoding it, which speeds up the process).