Configure FFmpeg anequalizer Filter Parameters

This article provides a practical guide on how to configure the filter parameters for the FFmpeg anequalizer (audio equalizer) filter. You will learn the exact syntax structure, the meaning of each parameter like frequency, gain, and width, and how to apply these settings to specific audio channels using real-world command-line examples.

The anequalizer filter is a high-order parametric multiband audio equalizer. It allows you to precisely target and adjust specific frequency bands in your audio streams.

Parameter Syntax

The configuration string for the anequalizer filter consists of one or more band specifications separated by the pipe character (|). Each band is defined using key-value pairs in the following format:

c{channel_index} f={frequency} w={width} g={gain} t={type}
  • c (Channel): Specifies which audio channel the band applies to (0-based indexing). For example, c0 is the left channel, and c1 is the right channel. If you omit this, the band is applied to all channels.
  • f (Frequency): Sets the central frequency of the band in Hz.
  • w (Width): Sets the bandwidth of the filter in Hz.
  • g (Gain): Sets the gain in dB. Positive values boost the frequency, while negative values cut it.
  • t (Type): Sets the filter type using an integer:
    • 0: Butterworth (default)
    • 1: Chebyshev Type I
    • 2: Chebyshev Type II

Practical Examples

1. Global Single-Band Equalization

To boost a central frequency of 1000 Hz by 6 dB with a bandwidth of 200 Hz across all audio channels, use the following command:

ffmpeg -i input.wav -af "anequalizer=f=1000 w=200 g=6 t=1" output.wav

2. Multiband Equalization

To configure multiple frequency bands, separate each configuration block with a |. This example boosts bass at 100 Hz and cuts harsh mids at 3000 Hz:

ffmpeg -i input.wav -af "anequalizer=f=100 w=50 g=10 t=0|f=3000 w=500 g=-6 t=0" output.wav

3. Channel-Specific Equalization

You can target individual audio channels. The following command applies a 5 dB boost at 500 Hz to the left channel (c0) and a 3 dB cut at 2000 Hz to the right channel (c1):

ffmpeg -i input.wav -af "anequalizer=c0 f=500 w=100 g=5 t=0|c1 f=2000 w=300 g=-3 t=0" output.wav