lv2dynparam is a LV2 plugin interface extension that enables plugin parameters to appear and disappear (i.e. number of voices). It also allows nested grouping of parameters. Groups can be used for things like ADSR abstraction, i.e. group of 4 float parameters. The extension consists of a header describing the extension interface and libraries, one for plugins and one for hosts, to expose functionality in more usable, from programmer point of view, interface.