Levelator was proprietary software released free of charge by a now defunct company. Levelator processed spoken audio files so the audio sounded correctly leveled for podcasts. It was a central tool in my podcast creation pipeline for more than twelve years.
When the 32-bit version of Levelator software stopped working on macOS Catalina, the time was right to put together the frequency analysis, AIFF I/O and JSON I/O in the Ape SDK to create an open source program that worked like Levelator.
Level Ape Source Code