I'm running Rhythmbox 3.4.2 (the latest version in Synaptic) on 18.04.6 LTS 32-bit.
The application opens without any apparent issues, my Music Library loads fine, and I can select and 'play' any of the tracks (both MP3 and WMA). However, there is no sound. This is a recent problem which now happens most of the time, although sound will randomly return without me doing anything.
I've tried uninstalling and reinstalling Rhythmbox, and I've made sure that the application isn't muted in the sound settings.
Related packages that are installed and up to date are:
gir1.2-rb-3.0
librhythmbox-core10
rhythmbox-data
rhythmbox-plugin-alternative-toolbar
rhythmbox-plugins
The same issue also affects Clementine. By contrast, there's always sound when using VLC or Audacious to play music files.
If anybody has any suggestions for a fix, I'd be very grateful.
Welcome to the community
For what I can conclude from your description, it must be a codec issue.
Both clementine and rhythmbox are depending on gstreamer
VLC and audacious both depend on libav.
It is, ofcourse, a bug. But since 18.04 is end-of-life there is not really a chance of getting it fixed.
However: You could try to install the "gstreamer1.0-libav" and see if that fixes things.
This is a gstreamer-codec that is actually a wrapper around the libav codecs.
It just might do the job.
sudo apt install gstreamer1.0-libav
Disclaimer: Now, I used to run 18.04/32bit on my almost 18 years old single-core+HT P4/32bit laptop but I changed it to Antix when 18.04 went end of life, 20.04 did not support 32-bit at all and Trisquel/32bit (MATE desktop) turned out to be a bit sluggish due to gtk3. So I am not able to test anything I propose here. Also, I've never used Clementine or Rhythmbox.
If you absolutely need a 32bit version of a distro with mate-desktop, your best bet is Trisquel. It is not as polished as Ubuntu-Mate but is pretty good (better than the debian version), and ...well... for 32-bit there is not much choice left. beggars can't be choosers eh?
