对两幅图像进行逼真的alpha混合，可以用于一些特效中。-two images of simulated alpha blending, can be used for some magic.

This source code describes how to dynamically mix two video files (.mpeg, .mpg, .avi and .dat). Mixing involves alpha-blending and stretching/shrinking and positioning of the two video streams, individually, using DirectShow s VMR9 filter. -This sour