说明：  本例提供了使用directshow代替opencv的vfw 的源代码,与转化为iplimage格式的算法. 实验中发现opencv的cvCaptureFromCAM 使用的是vfw,采用消息机制,速度较慢,测试发现fps只有 9-12左右,太慢了. 发现经过使用directshow后速度提升到60帧/s。
(Provided in this case the use of DirectShow to replace the VFW opencv source code, and translated into algorithms iplimage format. Opencv experiment found the cvCaptureFromCAM using vfw, the use of information mechanism to slow fps test found that only about 9-12, too slow. discovered through the use of DirectShow to speed after 60/s.)