filter 实现mpg4，h263,h264,divx等格式的解码，使用汇编内核，可能阅读起来有点麻烦，但filter部分使用的是标准的c++可以结合这些理解-filter realize mpg4, h263, h264, divx and other format decoder, use the compilation of the kernel, you may read up a little trouble, but the filter used is a standard