Fake webcam for adobe flash player

I would like to make a fake webcam or "software" webcam that would stream videos/music from a computer file. The flash player can stream a webcam but not video. The idea is to trick adobe flash into thinking it is streaming from a webcam, but instead stream a computer video file. This is for flash player only. What is the simplest way to do it. Does adobe flash uses directx interface to access the camera, and if 开发者_开发百科so is it possible to avoid making a windows driver?