I have a DirectShow application that simply plays an Mp3. Now I want to be able to moniter the sound output so that I can get visualizations to 'follow' the music(much like winamp or the WindowsMediaPlayer does). How should I go about checking the speaker output so that I can do this? Is there a member function to do this?
NOTE: I'm NOT asking a graphics question, I got that alright.

Oh yea, Im using these:
IGraphBuilder *pGraph;
IMediaControl *pMediaControl;
IMediaEvent *pEvent;