一个最简单的DirectShow的Filter源程序，适合初学者学习如何编写自己的Filter。-One of the most simple of Filter DirectShow source for beginners to learn how to write your own Filter.

directshow开发，一个不带pin的空filter.主要是方便初学者了解filter的架构。-the directshow develop, without pin empty the filter is easy for beginners to understand the filter architecture.

this code is a sample for directshow filter transform that i use in my project