How to Use FFmpeg Vibrato Filter for Audio

This article provides a quick guide on how to use the vibrato audio filter in FFmpeg to apply frequency modulation to your audio files. You will learn the syntax of the filter, understand its key parameters for adjusting modulation speed and depth, and see practical command-line examples to help you achieve the perfect pitch-modulation effect.

Understanding the Vibrato Filter

The FFmpeg vibrato filter applies a sinusoidal frequency modulation to an audio stream, resulting in a pitch-shifting “vibrato” effect. This is commonly used in music production and sound design to add warmth, movement, or eerie, sci-fi sound effects to vocal and instrumental tracks.

The filter accepts two main parameters:

• f (frequency): Specifies the modulation frequency in Hertz (Hz). This controls how fast the pitch fluctuates. The valid range is 0.1 to 20000.0 Hz, with a default value of 5.0 Hz.
• d (depth): Specifies the modulation depth, which controls how far the pitch bends. The valid range is 0.0 to 1.0, with a default value of 0.5. Higher values result in more extreme pitch variation.

Basic Command Syntax

To apply the filter, use the -af (audio filter) flag followed by vibrato and your desired parameters in the following format:

ffmpeg -i input.wav -af "vibrato=f=frequency_value:d=depth_value" output.wav

Example 1: Standard Subtle Vibrato

To apply a standard, natural-sounding vibrato with a speed of 6 Hz and a subtle depth of 0.3, use this command:

ffmpeg -i input.mp3 -af "vibrato=f=6.0:d=0.3" output.mp3

Example 2: Extreme Pitch Modulation (Sci-Fi Effect)

If you want to create a dramatic, fast-wobbling sound effect, increase both the frequency and the depth:

ffmpeg -i input.wav -af "vibrato=f=12.0:d=0.8" output.wav

Example 3: Slow Chorus-Like Pitch Bend

For a slow, drifting pitch modulation that mimics a detuned tape or chorus effect, set a very low frequency and a moderate depth:

ffmpeg -i input.wav -af "vibrato=f=1.5:d=0.4" output.wav