CoCreateInstance hangs when called from OnThreadCreate

Question

I have a problem with CoCreateInstance which doesn't ever return after being called. Its called from a overriden method of CSourceStream::OnThreadCreate

I think the problem is that I try to use COM inside a seperate thread but I am not sure. How do I use COM inside another thread? Here is the call stack and how I call the function anyways. I checked that CoInitialiseEx returns S_FALSE, so com is running on that thread.

HRESULT hr = CoCreateInstance(CLSID_FilterGraph, NULL,
        CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pGraph));

I found out that if I use CoCreateInstance in another method(CSourceStream::FillBuffer) that runs on the same thread it works but I don't know why.

When CoCreateInstance hangs, its stuck on WaitForMultipleObjectsEx, like so:

Answer 1

Like Simon said in the comments, changing CLSID_FilterGraph to CLSID_FilterGraphNoThread removed the deadlock.