How to Use FFmpeg Vibrato Filter for Pitch Modulation

This guide explains how to use the vibrato audio filter in FFmpeg to apply pitch modulation to your audio files. You will learn the basic syntax, the key parameters for controlling the modulation’s speed and depth, and practical command-line examples to help you achieve the exact audio effect you need.

Understanding the Vibrato Filter

The FFmpeg vibrato filter modulates the pitch of an audio stream using a low-frequency oscillator (LFO). This creates a pulsating, wavering pitch effect commonly heard in music and vocal processing.

The filter accepts two primary parameters:

f (frequency): Controls the modulation frequency in Hertz (Hz), which dictates how fast the pitch wavers. The default value is 5.0 Hz. The allowed range is 0.1 to 20000.0 Hz.
d (depth): Controls the modulation depth, which dictates how drastically the pitch changes. The default value is 0.5. The allowed range is 0.0 to 1.0 (where 0.0 is no effect and 1.0 is maximum pitch modulation).

Basic Command Syntax

To apply the filter, use the -af (audio filter) flag followed by vibrato.

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

Practical Examples

1. Applying Default Vibrato

If you do not specify any parameters, FFmpeg will apply the default settings (5.0 Hz frequency and 0.5 depth).

ffmpeg -i input.mp3 -af "vibrato" output.mp3

2. Creating a Slow, Deep Vibrato

To create a slow, dramatic pitch bend, lower the frequency and increase the depth. This example sets the frequency to 2.0 Hz and the depth to 0.8.

ffmpeg -i input.wav -af "vibrato=f=2.0:d=0.8" output.wav

3. Creating a Fast, Subtle Vibrato (Tremolo-like Pitch Effect)

For a rapid, subtle shimmer, increase the frequency and decrease the depth. This example sets the frequency to 10.0 Hz and the depth to 0.2.

ffmpeg -i input.wav -af "vibrato=f=10.0:d=0.2" output.wav

4. Combining Vibrato with Video

If you are processing a video file and want to apply the vibrato filter to the audio stream while keeping the video stream untouched, use the following command:

ffmpeg -i input.mp4 -c:v copy -af "vibrato=f=6.0:d=0.4" output.mp4

(Note: -c:v copy ensures the video is stream-copied without re-encoding, saving time and preserving quality).