MP3Gain

MP3Gain is an audio normalization software tool. The tool is available on multiple platforms and is free software. It analyzes the MP3 and reversibly changes its volume. The volume can be adjusted for single files or as album where all files would have the same perceived loudness. It is an implementation of ReplayGain. In 2015 Debian and Ubuntu removed it from their repositories due to a lack of an active maintainer.