Out of the box installation was not working, use Synaptic to install instead.
- Install Asunder through Synaptic
- Install Lame and Lame-Doc through Synaptic
$ sudo apt-get install asunder lame
For Rhythmbox on Ubuntu 19.04
- $ sudo apt-get install gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-tools
