How to Apply High-Pass Filter in FFmpeg

This article provides a quick, step-by-step guide on how to use the FFmpeg command-line tool to apply a high-pass filter to an audio file. You will learn the exact command needed to eliminate low-frequency background noise and rumble below 80Hz, helping you achieve cleaner and more professional audio tracks.

The Basic Command for 80Hz Cutoff

To remove low-end rumble below 80Hz from an audio file, use FFmpeg’s audio filter (-af) flag with the highpass filter. Run the following command in your terminal:

ffmpeg -i input.mp3 -af "highpass=f=80" output.mp3

Command Breakdown

• -i input.mp3: Specifies the path to your input audio file.
• -af "highpass=f=80": Applies the audio filter. highpass is the filter name, and f=80 sets the cutoff frequency to 80 Hz. Any frequencies below this threshold will be attenuated.
• output.mp3: The name of the newly created, filtered audio file.

Increasing the Filter Steepness (Poles)

By default, the high-pass filter in FFmpeg uses a single-pole filter, which has a gentle roll-off. If you still hear low-end rumble, you can make the cutoff steeper by increasing the number of poles using the p parameter.

The number of poles can be set from 1 to 20 (the default is 2). To apply a sharper, double-pole cutoff at 80Hz, use this command:

ffmpeg -i input.mp3 -af "highpass=f=80:p=2" output.mp3

Applying the Filter to Video Files

If you are working with a video file and want to filter the audio without re-encoding the video track, you can copy the video stream directly. This saves processing time and preserves video quality:

ffmpeg -i input.mp4 -vcodec copy -af "highpass=f=80" output.mp4