Playing music with Media Engine on Windows 8 - c++

Question

I am porting a Windows Phone 8 app to Windows 8 and it seems that Media Engine library works differently.
Here is my initialization code that works on WP8:
DX::ThrowIfFailed(
MFStartup(MF_VERSION)
);
ComPtr<IMFMediaEngineClassFactory> mediaEngineFactory;
ComPtr<IMFAttributes> mediaEngineAttributes;
// Create the class factory for the Media Engine.
DX::ThrowIfFailed(
CoCreateInstance(CLSID_MFMediaEngineClassFactory, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&mediaEngineFactory))
);
// Define configuration attributes.
DX::ThrowIfFailed(
MFCreateAttributes(&mediaEngineAttributes, 1)
);
ComPtr<MediaEngineNotify> notify = Make<MediaEngineNotify>();
ComPtr<IUnknown> unknownNotify;
DX::ThrowIfFailed(
notify.As(&unknownNotify)
);
DX::ThrowIfFailed(
mediaEngineAttributes->SetUnknown(MF_MEDIA_ENGINE_CALLBACK, unknownNotify.Get())
);
// Create the Media Engine.
DX::ThrowIfFailed(
mediaEngineFactory->CreateInstance(0, mediaEngineAttributes.Get(), &m_mediaEngine)
);
CreateInstance() throws 0xc00d36e6 exception ( MF_E_ATTRIBUTENOTFOUND ).
I've tried to search for samples for Media Engine playback of mp3s but can only find Video Playback samples.
Any ideas?

Answer 1

I figured out the missing attribute. I had to add MF_MEDIA_ENGINE_AUDIO_CATEGORY to specify what M the Media Engine is actually doing. Here is an example that works for both WP8 and WIN8:
#if PLATFORM_WINDOWS8
DX::ThrowIfFailed(
MFStartup(MF_VERSION)
);
#endif
ComPtr<IMFMediaEngineClassFactory> mediaEngineFactory;
ComPtr<IMFAttributes> mediaEngineAttributes;
// Create the class factory for the Media Engine.
DX::ThrowIfFailed(
CoCreateInstance(CLSID_MFMediaEngineClassFactory, nullptr, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&mediaEngineFactory))
);
// Define configuration attributes.
DX::ThrowIfFailed(
MFCreateAttributes(&mediaEngineAttributes, 1)
);
ComPtr<MediaEngineNotify> notify = Make<MediaEngineNotify>();
ComPtr<IUnknown> unknownNotify;
DX::ThrowIfFailed(
notify.As(&unknownNotify)
);
DX::ThrowIfFailed(
mediaEngineAttributes->SetUnknown(MF_MEDIA_ENGINE_CALLBACK, unknownNotify.Get())
);
DWORD flags=0;
#if PLATFORM_WINDOWS8
DX::ThrowIfFailed(
mediaEngineAttributes->SetUINT32(MF_MEDIA_ENGINE_AUDIO_CATEGORY, AudioCategory_GameMedia)
);
flags = MF_MEDIA_ENGINE_AUDIOONLY | MF_MEDIA_ENGINE_REAL_TIME_MODE;
#endif
// Create the Media Engine.
DX::ThrowIfFailed(
mediaEngineFactory->CreateInstance(flags, mediaEngineAttributes.Get(), &m_mediaEngine)
);