Is there a way to setup a plugin to anycrhronnously receive video frames from a specified pipe?

i'm assuming that by "pipe" you mean an external source as opposed to AE being the source.

if that is indeed the case, then the issue if reconciling the random AE render calls, and the async pipe.

for the async pipe, you can setup a separate thread (regular c++ thread, nothing to do with the AE SKD), and have it read/write data to some pre-allocated memory. with a mutex, you can access that memory from both the async pipe and AE's calls. if you want to "force" AE to talk to the pipe thread asap, you can use AEGP_CauseIdleRoutinesToBeCalled(). (look it up in the docs)

as for sending and fetching frames, this is a bit of a design challange.

ae would call your plugin to render at some pretty random times, and in not in sequential order. if you want to send away whatever was just rendered, that's pretty straight foreward. lock the mutex and write to the pipe buffer.

however, if your plug-in requires some external frame that is still unavailble at the time of the render call... eeesh... now you need to choose between a couple of bad options: either stalling until the async thread fetches the frame, or telling AE the render failed, which would terminate the current render/preview.

so, in regards to using external async-gotten frames in an AE render, you need to plan the work scheme well so that you would minize occurences where not all required resources are available to the plugin at the time of a render call.