MOC doesn't recognize mp3 files?

Forums:

MOC version: 
2.6-alpha3

I'm running Ubuntu 18.04 LTS with i3-gaps on an old MacBook Pro (2010ish). In terminal, ls shows that I have an mp3 file named 'Deep Field' (quotes are shown in terminal as well, and that's the name of the song) but in MOC it doesn't recognize that I have an mp3 in that directory. Does anyone have any ideas? This same problem occurred on Cmus, but still no clue how to fix this.

If MOC doesn't show mp3 files, it suggests that mp3 decoder was not installed. As far as I know Ubuntu installs it by default (in /usr/lib/x86_64-linux-gnu/moc/decoder_plugins/libmp3_decoder.so according to https://packages.ubuntu.com/bionic/amd64/moc/filelist). If you don't have anything funny in .moc/config file it probably means there is some problem with libmad library. You can check if the plugin was loaded by running MOC via mocp -SF and check the "Loaded xx decoders:" line.

You can start MOC client in other window and try to navigate to the directory with the mp3 file and see if some error message appears in the first window.