Convert an audiofile with only the left channel to a two-channel audio file with ffmpeg.

By creating a stereo output from mono, the same audio info will be placed in both channels and the channels will be identical.

Check if ffmpeg is installed on your machine:

$ ffmpeg -version
ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers

If you do not have it, install from ffmpeg.org

Python users can use PIP install

pip install ffmpeg

Usage: Convert mono to stereo

ffmpeg -i mono.mp3 -ac 2 stereo.mp3