Nikolay Sivov (@nsivov) commented about dlls/mf/tests/transform.c:
+ ULONG h264_encoded_data_len; + IMFTransform *transform; + LONGLONG duration, time; + DWORD output_status; + ULONG i, j, ret; + HRESULT hr; + + hr = CoInitialize(NULL); + ok(hr == S_OK, "Failed to initialize, hr %#lx.\n", hr); + + winetest_push_context("h264dec timestamps"); + + /* Test when no framerate is provided and samples contain no timestamps */ + if (FAILED(hr = CoCreateInstance(class_id, NULL, CLSCTX_INPROC_SERVER, + &IID_IMFTransform, (void **)&transform))) + goto failed; I think you can use CLSID_ symbol directly here, if you don't plan to reuse testing function for other decoders.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/7563#note_98519