igraphbuilder::renderfile()失败,vfw_e_bad_key-0x800403f2

继续调查 embedded WindowsMediaPlayer problem ,我正在尝试通过DirectShow进程内服务器进行简单的文件播放:

::CoInitializeEx(0, COINIT_MULTITHREADED);

CComPtr<IGraphBuilder> spGraph;
spGraph.CoCreateInstance(CLSID_FilterGraph, 0, CLSCTX_INPROC_SERVER);
CComQIPtr<IMediaControl> spMediaControl(spGraph);

// ... later:
spGraph->RenderFile(L"c:\\foo.wav", 0); // fails with VFW_E_BAD_KEY
spMediaControl->Run();

有趣的是,这在我测试的两个系统(windows xp 32&x64)上都运行得很好。
但是在我的实际用例中,它失败了,一个基于npapi的浏览器插件,即加载到firefox/chrome/opera中的dll。

有人知道这里会出什么问题吗?
或者有什么想法可以尝试?

更新: 也被问到 Microsoft forums .

小精灵:
IGraphBuilder::AddSourceFilter(path,path,&base) 以下注册表调用已失败(如进程监视器中所示):

"RegOpenKey","HKCU\Software\Classes\c","NAME NOT FOUND","Desired Access: Query Value, Maximum Allowed" 
"RegOpenKey","HKCU\Software\Classes\Media Type\Extensions\.wav","NAME NOT FOUND","Desired Access: Read" 
"RegOpenKey","HKCU\Software\Classes\Media Type","NAME NOT FOUND","Desired Access: Read"