The audio/ffmpeg-normalize port
ffmpeg-normalize-1.23.0p1 – audio normalization
This program normalizes media files using FFmpeg to a certain loudness level
using the EBU R128 loudness normalization procedure. It can also perform
RMS-based normalization (where the mean is lifted or attenuated), or peak
normalization to a certain target level. Batch processing of several input
files is possible, including video files.