Executar no Terminal:
sudo add-apt-repository ppa:jon-severinsson/ffmpeg
sudo apt-get update
sudo apt-get install ffmpeg
Editar o arquivo
~/.config/openbox/lubuntu-rc.xml
Exemplo:
<keybind key="C-Super_L">
<action name="Execute">
<command>lxpanelctl run</command>
</action>
</keybind>