I need to deploy an app that has Phonon dynamically linked on a windows platform. I am not compiling Qt from source but am using the Qt SDK as is.

For now...
I have QtCore, QtGui, QtOpenGL, and Phonon DLLS in the same directory as the application.
I have the phonon_backend directory, with it's contents, there too.

When I move this tree to a non-development machine (read: Qt SDK not installed) the MediaWidget just does not show. Everything works on my development machine.

What piece am I missing? A plugin? Another DLL?

Phonon::BackendCapabilities::availableMimeTypes() tells me a list of types, so I know it sees the phonon_backend DLLs.