Pipe into Avisynth like opposite of avs2yuv???

I'm using an NLE that allows 'playing out' of projects without encoding via a command line player. I'd like to process the output through Avisynth and out to an encoder like x264. Any suggestions as to how this may be possible. Some sort of opposite to avs2yuv?

which NLE ? debugmode frameserver works for several NLE's

Reading from pipes with Avisynth is a somewhat risky proposition. First of all, Avisynth must know the number of frames immediately upon construction of the script environment. Secondly, Avisynth does not provide any way of enforcing linear access, so temporal filters may access frames out-of-order, which may (depending on frame caching) lead to insanity.