My favorite music player is undoubtedly Spotify. It is not a secret that its Linux support might not be the best and that some artists have just decided not to upload the music in the service. One of them is Tool, one of my favorite bands, too. I recently decided to play my Tool mp3 files with Spotify as local files and they were not playing. In order to fix that one has to:

  1. Add deb http://ftp.us.debian.org/debian jessie main to /etc/apt/sources.list.
  2. Install the following packages:
sudo apt install libavcodec-extra-56 libavformat56

Problem solved. This is working for me with Debian unstable in 2019.