多线程时Filter的怪异问题

[gaofg]

相关代码如下：
UINT CFilterGraph::WaitingThrd(void * pParam)
{
CFilterGraph * pGraph = (CFilterGraph *) pParam;
if (pGraph != NULL && pGraph->m_pDataList != NULL)
{
::WaitForSingleObject(pGraph->m_pDataList->m_hBufEnough, INFINITE);
if (!pGraph->IsRunning())
{
pGraph->Run();
/*
long evCode = 0;
pGraph->m_pME->WaitForCompletion(INFINITE, &evCode);
*/
}
}
return 1;
}


bool CFilterGraph::StartGraph(void)
{
...
// Waiting for event to start filter graph，等待一定的数据后才开始run filter
::AfxBeginThread((AFX_THREADPROC)CFilterGraph::WaitingThrd, this);
...
}


UINT GraphThread( LPVOID pParam )
{
AfxOleInit();
CFilterGraph *pthrd = (CFilterGraph *)pParam;

if(!pthrd->BuildGraph())
{
AfxMessageBox("Build Filter Graph Manager Failed!");
return FALSE;
}

if(!pthrd->StartGraph())
{
AfxMessageBox("Filter Graph Manager Was not Started!");
return FALSE;
}

// Sleep(60000); //如果没有则没有图像显示
return 0;
}


对话框通过如下方式来创建线程：
m_pGraph = new CFilterGraph();
m_pGraph->SetVideoWndOwner(GetDlgItem(IDC_PICTURE)->GetSafeHwnd()); // 窗口句柄
AfxBeginThread(GraphThread, (LPVOID)m_pGraph);

问题是：如果没有上面的Sleep语句，则没有图像播放出，但Filter已经创建了。加上Sleep后则在
指定的时间后停止播放。但是这种方式显然不是解决问题的办法。而且即使如上注释中使用WaitForCompletion也还是不行。而以前对Filter不采用单独线程即在对话框中直接创建并运行则是正常的。

请指教，谢谢了！