Configure FFmpeg Loudnorm True Peak and Loudness Range

This article provides a practical guide on how to configure the True Peak (tp) and Loudness Range (lra) target parameters in FFmpeg’s loudnorm filter. You will learn the correct command-line syntax for both single-pass and two-pass audio normalization to meet specific broadcast or streaming standards.

The loudnorm filter in FFmpeg is an automatic loudness normalization filter that complies with the EBU R128 standard. To customize the output audio to your specific target requirements, you must define the target parameters within the filter argument.

Key Parameters

• i (Integrated Loudness): The target integrated loudness in LUFS. The default is -24.0.
• lra (Loudness Range): The target loudness range in LU. The default is 7.0.
• tp (True Peak): The target maximum true peak in dBTP. The default is -2.0.

Basic Syntax (Single-Pass)

For a quick, single-pass normalization where you set the True Peak to -1.0 dBTP and Loudness Range to 15.0 LU, use the following syntax:

ffmpeg -i input.wav -filter:a loudnorm=i=-24:tp=-1.0:lra=15.0 output.wav

In this example: * i=-24 sets the target integrated loudness to -24 LUFS. * tp=-1.0 limits the maximum true peak to -1.0 dBTP. * lra=15.0 sets the allowed loudness dynamic range to 15 LU.

Recommended Workflow (Two-Pass)

While single-pass is fast, it relies on estimation. For professional-grade compliance, a two-pass approach is highly recommended.

Pass 1: Analyze the Audio Run the filter with print_format=json to analyze the input file’s current properties.

ffmpeg -i input.wav -filter:a loudnorm=print_format=json -f null -

This command outputs JSON data in your terminal containing measured values such as input_i, input_lra, input_tp, and input_thresh.

Pass 2: Apply Normalization with Targets Use the measured values from Pass 1 along with your desired tp and lra targets to perform the final normalization.

ffmpeg -i input.wav -filter:a loudnorm=i=-24:tp=-1.5:lra=10.0:measured_i=-18.5:measured_tp=1.2:measured_lra=12.1:measured_thresh=-29.4 output.wav

By providing the measured input values to the filter, FFmpeg can precisely adjust the audio to meet your exact tp and lra targets without unexpected compression or clipping.