AVS is a plugin, yes - my Winamp v2.75 came with two "visualisation" plugins, vis_avs.dll and vis_nsfs.dll which I found in Program Files\Winamp\Plugins
underneath which in Program Files\Winamp\Plugins\avs
came a whole load of ready made presets *.avs
(NB I found that vis_nsfs.dll tended to crash sometimes; but vis_avs seems stable)
The fun thing about AVS is that it has an editor so you can play with it...
Try looking in Preferences
down to Plugins>Visualisation: there's a link "get plugins" on mine...
or, if you find you have AVS listed on that screen it might need to be selected to enable it (first time after install...)
if you have it selected, the quick start is CtrlShiftK; then double-click in the AVS window to get to the editor; then set up for fullscreen using the editor menus (absolutely no idea how much of this is the same in later versions!)
best wishes, HJ.
AVS editor screen: set fullscreen mode before using fullscreen! render superscope does many things
(both ~120k jpg)