Which parts of DirectShow's Filter Graph Manager are thread safe?

The MSDN doesn't say. IGraphBuilder has a function Abort. That implies that at the very least it's safe to call Abort and any one other IGraphBuilder function at the same time. With this question, I want to obtain proof that Filter Graph Manager is thread开发者_如何学Go safer than that.

DirectShow is thread safe and is typically working on multiple threads even in simple scenarios. For example, a source filter typically owns its own worker thread and streams from there.