Windows Media Foundation using IMFTransform to decode mp4 movie frames to 2D textures

I'm trying to decode an mp4 video using Windows Media Foundation classes and converting frames in to 2D textures that can be used by a DirectX shader for rendering. I've been able to read the source stream using MFCreateSourceReaderfromURL and been able to read the media type of the stream which has its major type MFMEdiaType_Video and minor type as MFVideoFormat_H264 as expected.

I'm now needing to convert this format in to an RGB format that could be used to initialise a D3D11_TEXTURE2D resource and resource view which can then be passed to a HLSL pixel shader for sampling. I've tired using the IMFTransform class to do the conversion for me but when I try to set the output type on the transform to any MFVideoFormat_RGB variant I get an error. I've also tried setting a new output type on the source reader and just Sampling that hoping to get a sample in the correct format but again I've had no luck.

So my questions would be:

• Is this type of conversion possible?

• Can this be done through the IMFTransform/SourceReader classes like I've tired above and do I just need to tweak the code or do I need to do this type of conversion manually?

• Is this the best way to go about feeding video texture data in to a shader for sampling or is there an easier alternative that I've not thought about.

The OS being used is Windows 7 so I can't use the SourceReaderEx or ID3D11VideoDevice interface because as far as I'm aware these solutions only seem available on Windows 8.

Any help/pointers in the right direction would be greatly appreciated, I can also provide some source code if necessary.