volumewheel lets you to use the mouse wheel to control the volume level in Totem (>= 3.12)

Install these dependencies:

sudo apt-get install gir1.2-clutter-1.0 gir1.2-gtkclutter-1.0 gir1.2-gtk-3.0 gir1.2-peas-1.0 gir1.2-pango-1.0

Download the repository and move the volumewheel directory to:

~/.local/share/totem/plugins/

and then you can enable it in Totem → Preferences → Plugins → Volume Wheel