[Spirou]

FernetMenta applied a fix for legacy OpenGL to pvr.vdr.vnsi. See https://github.com/FernetMenta/pvr.vdr.v...44433b352c
Looks the same fix is required for visualization.spectrum to make it work with legacy OpenGL on Ubuntu 16.04.3.

[spiff]

thanks. this was already in the queue and has been merged.