How to properly use a hardware accelerated Media Foundation Source Reader to decode a video?

Question

I\'m in the process of writing a hardware accelerated h264 decoder using Media Foundation\'s Source Reader, but have encountered a problem. I followed this tutorial and supporte

Answer 1

Your code is correct, conceptually, with the only remark - and it's not quite obvious - that Media Foundation decoder is multithreaded. You are feeding it with a single threaded version of Direct3D device. You have to work it around or you get what you are currently getting: access violations and freezes, that is undefined behavior.

    // NOTE: No single threading
    handle_result(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 
        (0 * D3D11_CREATE_DEVICE_SINGLETHREADED) | D3D11_CREATE_DEVICE_VIDEO_SUPPORT,
        levels, ARRAYSIZE(levels), D3D11_SDK_VERSION, &device, nullptr, nullptr));

    // NOTE: Getting ready for multi-threaded operation
    const CComQIPtr pMultithread = device;
    pMultithread->SetMultithreadProtected(TRUE);

Also note that this straightforward code sample has a performance bottleneck around the lines you added for getting contiguous buffer. Apparently it's your move to get access to the data... however behavior by design is that decoded data is already in video memory, and your transfer to system memory is an expensive operation. That is, you added a severe performance hit to the loop. You will be interested in checking validity of data this way, and when it comes to performance benchmarking you should rather comment that out.