I have understand because vlc crash to enable projectM: the cause is a wrong reference to a font in vlc.
In vlc settings: all settings, audio/visualization/projectm and to change the fonts in:
(i'm sorry if it is unclear but i have vlc in italian language).
After to reboot vlc and projectm works in vlc
Clementine i think it is same problem but i can't understabnd to change the reference to the fonts
If i understand this way i'll write here