I`m new to media foundation and C++. But I want to create a virtual video capture device which can be used by Microsoft Expression Encoder. Can you tell me in which direction to look? I think it should be something working asynchronously and a source will be byte stream from mobile device. Thanks in advance.
I don't think you want to look into Media Foundation for this. Expression Encoder uses a richer API to capture video with, DirectShow. You want a virtual DirectShow camera, which was discussed multiple times and has a simple sample project to start from.
Supported USB Capture Devices Expression Encoder 4:
Any device that provides a dshow filter is supported by EE4. Currently, there is no list currently available of supported devices, though most usb devices have little to no issues with encoder.