WLMFDS.dll

Source	src/WLMFDS/
CMake target	WLMFDS
Type	Win32 COM DLL (427 KB / 345 KB code in the original, 28+ RTTI classes)
Family	Media Foundation targets

At a glance

The Media Foundation / DirectShow bridge. Its job: let legacy DirectShow-encoded content play and transcode through the modern Media Foundation pipeline. Responsibilities documented in the public header:

• Filter-graph serialization (DirectShow graph description ↔ MF)
• DShow-to-MF source resolution — producing IMFSourceReaders over DirectShow media
• EVR (Enhanced Video Renderer) integration for hardware-accelerated preview

Public surface

The standard COM quartet (WLMFDS.def):

DllCanUnloadNow     DllGetClassObject
DllRegisterServer  DllUnregisterServer

Role in the pipeline

MovieMakerCore's DShowMFSourceReaderBuilder (in HMRAVSource) is the in-engine client: when a media file is not natively supported by MF, resolution falls through to this bridge — see the HMRAVSource flow.

Implementation notes

• Built with MSVC 11.0-era header conventions (STRICT, WIN32_LEAN_AND_MEAN, WINVER 0x0602), like the other media DLLs.
• COM status: DllGetClassObject currently returns CLASS_E_CLASSNOTAVAILABLE — no servable COM classes are implemented yet — and DllRegisterServer / DllUnregisterServer return S_OK without writing registration. The COM surface is a documented stub category (see Stub Design).

Testing

• tests/WLMFDS/ — per-module C++ tests.
• Contract coverage for COM activation in tests/mmr-python.

Analysis artifacts

analysis/WLMFDS/ (PDB GUID {41188442-2579-4939-8E66-6697FE148922}) and analysis/SharedMFDlls/.