directshow不能播放MP4文件
这个问题网上有些讨论，但是都不太清楚，哪位高手给个比较详细的答案啊？

THX

附录：一个简单的directshow视频播放程序，可以支持.wmv，.avi等，但是不能播放MP4格式的文件，应该怎么改啊？

#include "stdafx.h"

#include <dshow.h>
void main(void)
{
IGraphBuilder *pGraph = NULL;
IMediaControl *pControl = NULL;
IMediaEvent *pEvent = NULL;

// Initialize the COM library.
HRESULT hr = CoInitialize(NULL);
if (FAILED(hr))
{
printf("ERROR - Could not initialize COM library");
return;
}

// Create the filter graph manager and query for interfaces.
hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER,
IID_IGraphBuilder, (void **)&pGraph);
if (FAILED(hr))
{
printf("ERROR - Could not create the Filter Graph Manager.");
return;
}

hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pControl);
hr = pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);

// Build the graph. IMPORTANT: Change this string to a file on your system.
hr = pGraph->RenderFile(L"D:\\VideoProcess\\TestVideo\\C18.mp4", NULL);
if (SUCCEEDED(hr))
{
// Run the graph.
hr = pControl->Run();
if (SUCCEEDED(hr))
{
// Wait for completion.
long evCode;
pEvent->WaitForCompletion(INFINITE, &evCode);

// Note: Do not use INFINITE in a real application, because it
// can block indefinitely.
}
}
pControl->Release();
pEvent->Release();
pGraph->Release();
CoUninitialize();
}





[解决办法]
你看看你的filter中有没有解码MP4的，在graph edit中先试试。没有的话在网上下一个filter注册上去再试！