difference between IMFSourceReader API and MFTEnumEx, finding decoders

Hi,

I have some troubles, finding decoders for "MFVideoFormat_DV25", "MFVideoFormat_DV50", "MFVideoFormat_DV100" as well as "MFVideoFormat_HEVC".

MFT_REGISTER_TYPE_INFO info = { MFMediaType_Video, subtype };
UINT32 unFlags = MFT_ENUM_FLAG_SYNCMFT | MFT_ENUM_FLAG_HARDWARE | MFT_ENUM_FLAG_SORTANDFILTER;

hr = MFTEnumEx(MFT_CATEGORY_VIDEO_DECODER, unFlags,
        &info, // Input type
        NULL, // Output type
        &ppActivate, &count);

"count" is always 0 for these GUIDs.

If I use the IMFSourceReader API, I can read and decode such video files with the GUID "MFVideoFormat_DV25" and "MFVideoFormat_DV50". The GUID subtype (MF_MT_SUBTYPE) of the IMFSourceReader API is as expected  {30357664-0000-0010-8000-00AA00389B71} - MFVideoFormat_DV50 - for example.

I couldn`t test the two other formats, because I do not have such files (at the moment). Do you know the difference between the IMFSourceReader API and MFTEnumEx? Why is the IMFSourceReader API able to find a decoder and the MFTEnumEx failed?

best regards

saoirse