DirectShow中的视频捕捉之三

为了创建可以预览视频的graph，可以调用下面的代码：

ICaptureGraphBuilder2 *pBuild;		//Capture Graph Builder
//Initialize pBuild(not shown)
...
IBaseFilter *pCap;									//Video capture filter
hr = pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video,
												pCap, NULL, NULL);