One of the fundamental problems in developing a plugin that deals with more than one frame at a time is that the plugin reportedly has no knowledge of which absolute frame it is currently working on. It only has a "progress" indication that is used to interpolate between keyframes. At least this is what I've been told by a couple of other developers.

BUT... there is a VV media generator (timecode) that apparently does have the ability to get absolute frame knowledge, since it can display the frame number (or time, etc.). How does it get that knowledge?