Added WinRT support for videoio.

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

modules/videoio/include/opencv2/videoio.hpp

@@ -50,6 +50,7 @@
   @{
     @defgroup videoio_c C API
     @defgroup videoio_ios iOS glue
+    @defgroup videoio_winrt WinRT glue
   @}
 */
 
@@ -85,8 +86,9 @@ enum { CAP_ANY          = 0,     // autodetect
        CAP_AVFOUNDATION = 1200,  // AVFoundation framework for iOS (OS X Lion will have the same API)
        CAP_GIGANETIX    = 1300,  // Smartek Giganetix GigEVisionSDK
        CAP_MSMF         = 1400,  // Microsoft Media Foundation (via videoInput)
-       CAP_INTELPERC    = 1500,   // Intel Perceptual Computing SDK
-       CAP_OPENNI2      = 1600,   // OpenNI2 (for Kinect)
+       CAP_WINRT        = 1410,  // Microsoft Windows Runtime using Media Foundation
+       CAP_INTELPERC    = 1500,  // Intel Perceptual Computing SDK
+       CAP_OPENNI2      = 1600,  // OpenNI2 (for Kinect)
        CAP_OPENNI2_ASUS = 1610   // OpenNI2 (for Asus Xtion and Occipital Structure sensors)
      };
 

modules/videoio/include/opencv2/videoio/cap_winrt.hpp

+// Video support for Windows Runtime
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#include <ppl.h>
+#include <functional>
+#include <concrt.h>
+#include <agile.h>
+
+using namespace Windows::UI::Xaml::Controls;
+
+namespace cv
+{
+
+//! @addtogroup videoio_winrt
+//! @{
+
+enum {
+    OPEN_CAMERA = 300,
+    CLOSE_CAMERA,
+    UPDATE_IMAGE_ELEMENT,
+    SHOW_TRACKBAR
+};
+
+/********************************** WinRT API ************************************************/
+
+template <typename ...Args>
+CV_EXPORTS void winrt_startMessageLoop(std::function<void(Args...)>&& callback, Args... args);
+
+template <typename ...Args>
+CV_EXPORTS void winrt_startMessageLoop(void callback(Args...), Args... args);
+
+/** @brief
+@note
+    Sets the reporter method for the HighguiAssist singleton. Starts the main OpenCV as
+    an async thread in WinRT. See VideoCapture for the example of callback implementation.
+    Here is how the class can be used:
+@code
+    void cvMain()
+    {
+        Mat frame;
+        VideoCapture cam;
+        cam.open(0);
+
+        while (1)
+        {
+            cam >> frame;
+
+            // don't reprocess the same frame again
+            if (!cam.grab()) continue;
+
+            // your processing logic goes here
+
+            // obligatory step to get XAML image component updated
+            winrt_imshow();
+        }
+    }
+
+    MainPage::MainPage()
+    {
+        InitializeComponent();
+
+        cv::winrt_setFrameContainer(cvImage);
+        cv::winrt_startMessageLoop(cvMain);
+    }
+@endcode
+*/
+template
+CV_EXPORTS void winrt_startMessageLoop(void callback(void));
+
+/** @brief
+@note
+    Must be called from WinRT specific callback to handle image grabber state.
+    Here is how the class can be used:
+@code
+    MainPage::MainPage()
+    {
+        // ...
+        Window::Current->VisibilityChanged += ref new Windows::UI::Xaml::WindowVisibilityChangedEventHandler(this, &Application::MainPage::OnVisibilityChanged);
+        // ...
+    }
+
+    void Application::MainPage::OnVisibilityChanged(Platform::Object ^sender,
+        Windows::UI::Core::VisibilityChangedEventArgs ^e)
+    {
+        cv::winrt_onVisibilityChanged(e->Visible);
+    }
+@endcode
+*/
+CV_EXPORTS void winrt_onVisibilityChanged(bool visible);
+
+/** @brief
+@note
+    Must be called to assign WinRT control holding image you're working with.
+    Code sample is available for winrt_startMessageLoop().
+*/
+CV_EXPORTS void winrt_setFrameContainer(::Windows::UI::Xaml::Controls::Image^ image);
+
+/** @brief
+@note
+    Must be called to update attached image source.
+    Code sample is available for winrt_startMessageLoop().
+*/
+CV_EXPORTS void winrt_imshow();
+
+//! @} videoio_winrt
+
+} // cv
\ No newline at end of file

modules/videoio/src/cap.cpp

@@ -43,6 +43,13 @@
 #include "cap_intelperc.hpp"
 #include "cap_dshow.hpp"
 
+// All WinRT versions older than 8.0 should provide classes used for video support
+#if defined(WINRT) && !defined(WINRT_8_0)
+#   include "cap_winrt_capture.hpp"
+#   include "cap_winrt_bridge.hpp"
+#   define WINRT_VIDEO
+#endif
+
 #if defined _M_X64 && defined _MSC_VER && !defined CV_ICC
 #pragma optimize("",off)
 #pragma warning(disable: 4748)
@@ -508,6 +515,9 @@ static Ptr<IVideoCapture> IVideoCapture_create(int index)
 #endif
 #ifdef HAVE_INTELPERC
         CV_CAP_INTELPERC,
+#endif
+#ifdef WINRT_VIDEO
+        CAP_WINRT,
 #endif
         -1, -1
     };
@@ -526,6 +536,7 @@ static Ptr<IVideoCapture> IVideoCapture_create(int index)
     {
 #if defined(HAVE_DSHOW)        || \
     defined(HAVE_INTELPERC)    || \
+    defined(WINRT_VIDEO)         || \
     (0)
         Ptr<IVideoCapture> capture;
 
@@ -540,6 +551,13 @@ static Ptr<IVideoCapture> IVideoCapture_create(int index)
             case CV_CAP_INTELPERC:
                 capture = makePtr<VideoCapture_IntelPerC>();
                 break; // CV_CAP_INTEL_PERC
+#endif
+#ifdef WINRT_VIDEO
+        case CAP_WINRT:
+            capture = Ptr<IVideoCapture>(new cv::VideoCapture_WinRT(index));
+            if (capture)
+                return capture;
+            break; // CAP_WINRT
 #endif
         }
         if (capture && capture->isOpened())
@@ -664,7 +682,29 @@ bool VideoCapture::read(OutputArray image)
 
 VideoCapture& VideoCapture::operator >> (Mat& image)
 {
+#ifdef WINRT_VIDEO
+    if (grab())
+    {
+        if (retrieve(image))
+        {
+            std::lock_guard<std::mutex> lock(VideoioBridge::getInstance().inputBufferMutex);
+            VideoioBridge& bridge = VideoioBridge::getInstance();
+
+            // double buffering
+            bridge.swapInputBuffers();
+            auto p = bridge.frontInputPtr;
+
+            bridge.bIsFrameNew = false;
+
+            // needed here because setting Mat 'image' is not allowed by OutputArray in read()
+            Mat m(bridge.height, bridge.width, CV_8UC3, p);
+            image = m;
+        }
+    }
+#else
     read(image);
+#endif
+
     return *this;
 }
 
@@ -760,4 +800,4 @@ int VideoWriter::fourcc(char c1, char c2, char c3, char c4)
     return (c1 & 255) + ((c2 & 255) << 8) + ((c3 & 255) << 16) + ((c4 & 255) << 24);
 }
 
-}
+}
\ No newline at end of file

modules/videoio/src/cap_winrt/CaptureFrameGrabber.cpp

+// Copyright (c) Microsoft. All rights reserved.
+//
+// The MIT License (MIT)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "MediaStreamSink.hpp"
+#include "MediaSink.hpp"
+#include "CaptureFrameGrabber.hpp"
+
+using namespace Media;
+using namespace Platform;
+using namespace Windows::Foundation;
+using namespace Windows::Media;
+using namespace Windows::Media::Capture;
+using namespace Windows::Media::MediaProperties;
+using namespace concurrency;
+using namespace Microsoft::WRL::Details;
+using namespace Microsoft::WRL;
+
+task<Media::CaptureFrameGrabber^> Media::CaptureFrameGrabber::CreateAsync(_In_ MediaCapture^ capture, _In_ VideoEncodingProperties^ props, CaptureStreamType streamType)
+{
+    auto reader = ref new Media::CaptureFrameGrabber(capture, props, streamType);
+
+    auto profile = ref new MediaEncodingProfile();
+    profile->Video = props;
+
+    task<void> task;
+    if (reader->_streamType == CaptureStreamType::Preview)
+    {
+        task = create_task(capture->StartPreviewToCustomSinkAsync(profile, reader->_mediaExtension));
+    }
+    else
+    {
+        task = create_task(capture->StartRecordToCustomSinkAsync(profile, reader->_mediaExtension));
+    }
+
+    return task.then([reader]()
+    {
+        reader->_state = State::Started;
+        return reader;
+    });
+}
+
+Media::CaptureFrameGrabber::CaptureFrameGrabber(_In_ MediaCapture^ capture, _In_ VideoEncodingProperties^ props, CaptureStreamType streamType)
+: _state(State::Created)
+, _streamType(streamType)
+, _capture(capture)
+{
+    auto videoSampleHandler = ref new MediaSampleHandler(this, &Media::CaptureFrameGrabber::ProcessSample);
+
+    _mediaSink = Make<MediaSink>(nullptr, props, nullptr, videoSampleHandler);
+    _mediaExtension = reinterpret_cast<IMediaExtension^>(static_cast<AWM::IMediaExtension*>(_mediaSink.Get()));
+}
+
+Media::CaptureFrameGrabber::~CaptureFrameGrabber()
+{
+    if (_state == State::Started)
+    {
+        if (_streamType == CaptureStreamType::Preview)
+        {
+            (void)_capture->StopPreviewAsync();
+        }
+        else
+        {
+            (void)_capture->StopRecordAsync();
+        }
+    }
+
+    if (_mediaSink != nullptr)
+    {
+        (void)_mediaSink->Shutdown();
+        _mediaSink = nullptr;
+    }
+    _mediaExtension = nullptr;
+    _capture = nullptr;
+}
+
+void Media::CaptureFrameGrabber::ShowCameraSettings()
+{
+#if WINAPI_FAMILY!=WINAPI_FAMILY_PHONE_APP
+    if (_state == State::Started)
+    {
+        CameraOptionsUI::Show(_capture.Get());
+    }
+#endif
+}
+
+task<void> Media::CaptureFrameGrabber::FinishAsync()
+{
+    auto lock = _lock.LockExclusive();
+
+    if (_state != State::Started)
+    {
+        throw ref new COMException(E_UNEXPECTED, L"State");
+    }
+    _state = State::Closing;
+
+    if (_mediaSink != nullptr)
+    {
+        (void)_mediaSink->Shutdown();
+        _mediaSink = nullptr;
+    }
+    _mediaExtension = nullptr;
+
+    task<void> task;
+    if (_streamType == CaptureStreamType::Preview)
+    {
+        task = create_task(_capture->StopPreviewAsync());
+    }
+    else
+    {
+        task = create_task(_capture->StopRecordAsync());
+    }
+
+    return task.then([this]()
+    {
+        auto lock = _lock.LockExclusive();
+        _state = State::Closed;
+        _capture = nullptr;
+    });
+}
+
+task<ComPtr<IMF2DBuffer2>> Media::CaptureFrameGrabber::GetFrameAsync()
+{
+    auto lock = _lock.LockExclusive();
+
+    if (_state != State::Started)
+    {
+        throw ref new COMException(E_UNEXPECTED, L"State");
+    }
+
+    _mediaSink->RequestVideoSample();
+
+    task_completion_event<ComPtr<IMF2DBuffer2>> taskEvent;
+    _videoSampleRequestQueue.push(taskEvent);
+
+    return create_task(taskEvent);
+}
+
+void Media::CaptureFrameGrabber::ProcessSample(_In_ MediaSample^ sample)
+{
+    task_completion_event<ComPtr<IMF2DBuffer2>> t;
+
+    {
+        auto lock = _lock.LockExclusive();
+
+        t = _videoSampleRequestQueue.front();
+        _videoSampleRequestQueue.pop();
+    }
+
+    ComPtr<IMFMediaBuffer> buffer;
+    CHK(sample->Sample->ConvertToContiguousBuffer(&buffer));
+
+    // Dispatch without the lock taken to avoid deadlocks
+    t.set(As<IMF2DBuffer2>(buffer));
+}
\ No newline at end of file

modules/videoio/src/cap_winrt/CaptureFrameGrabber.hpp

+// Copyright (c) Microsoft. All rights reserved.
+//
+// The MIT License (MIT)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#pragma once
+
+#include "MFIncludes.hpp"
+
+
+namespace Media {
+
+class MediaSink;
+
+enum class CaptureStreamType
+{
+    Preview = 0,
+    Record
+};
+
+ref class CaptureFrameGrabber sealed
+{
+public:
+
+    // IClosable
+    virtual ~CaptureFrameGrabber();
+
+    virtual void ShowCameraSettings();
+
+internal:
+
+    static concurrency::task<CaptureFrameGrabber^> CreateAsync(_In_ WMC::MediaCapture^ capture, _In_ WMMp::VideoEncodingProperties^ props)
+    {
+        return CreateAsync(capture, props, CaptureStreamType::Preview);
+    }
+
+    static concurrency::task<CaptureFrameGrabber^> CreateAsync(_In_ WMC::MediaCapture^ capture, _In_ WMMp::VideoEncodingProperties^ props, CaptureStreamType streamType);
+
+    concurrency::task<MW::ComPtr<IMF2DBuffer2>> GetFrameAsync();
+    concurrency::task<void> FinishAsync();
+
+private:
+
+    CaptureFrameGrabber(_In_ WMC::MediaCapture^ capture, _In_ WMMp::VideoEncodingProperties^ props, CaptureStreamType streamType);
+
+    void ProcessSample(_In_ MediaSample^ sample);
+
+    Platform::Agile<WMC::MediaCapture> _capture;
+    ::Windows::Media::IMediaExtension^ _mediaExtension;
+
+    MW::ComPtr<MediaSink> _mediaSink;
+
+    CaptureStreamType _streamType;
+
+    enum class State
+    {
+        Created,
+        Started,
+        Closing,
+        Closed
+    } _state;
+
+    std::queue<concurrency::task_completion_event<MW::ComPtr<IMF2DBuffer2>>> _videoSampleRequestQueue;
+    AutoMF _mf;
+    MWW::SRWLock _lock;
+};
+
+}
\ No newline at end of file

modules/videoio/src/cap_winrt/MFIncludes.hpp

+// Header for standard system include files.
+
+// Copyright (c) Microsoft. All rights reserved.
+//
+// The MIT License (MIT)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#pragma once
+
+#include <collection.h>
+#include <ppltasks.h>
+
+#include <wrl\implements.h>
+#include <wrl\wrappers\corewrappers.h>
+#include <Roerrorapi.h>
+
+#include <queue>
+#include <sstream>
+
+#include <robuffer.h>
+
+#include <mfapi.h>
+#include <mfidl.h>
+#include <Mferror.h>
+
+#include <windows.media.h>
+#include <windows.media.mediaproperties.h>
+
+namespace AWM = ::ABI::Windows::Media;
+namespace AWMMp = ::ABI::Windows::Media::MediaProperties;
+namespace AWFC = ::ABI::Windows::Foundation::Collections;
+namespace MW = ::Microsoft::WRL;
+namespace MWD = ::Microsoft::WRL::Details;
+namespace MWW = ::Microsoft::WRL::Wrappers;
+namespace WMC = ::Windows::Media::Capture;
+namespace WF = ::Windows::Foundation;
+namespace WMMp = ::Windows::Media::MediaProperties;
+namespace WSS = ::Windows::Storage::Streams;
+
+// Exception-based error handling
+#define CHK(statement)  {HRESULT _hr = (statement); if (FAILED(_hr)) { throw ref new Platform::COMException(_hr); };}
+#define CHKNULL(p)  {if ((p) == nullptr) { throw ref new Platform::NullReferenceException(L#p); };}
+
+// Exception-free error handling
+#define CHK_RETURN(statement) {hr = (statement); if (FAILED(hr)) { return hr; };}
+
+// Cast a C++/CX msartpointer to an ABI smartpointer
+template<typename T, typename U>
+MW::ComPtr<T> As(U^ in)
+{
+    MW::ComPtr<T> out;
+    CHK(reinterpret_cast<IInspectable*>(in)->QueryInterface(IID_PPV_ARGS(&out)));
+    return out;
+}
+
+// Cast an ABI smartpointer
+template<typename T, typename U>
+Microsoft::WRL::ComPtr<T> As(const Microsoft::WRL::ComPtr<U>& in)
+{
+    Microsoft::WRL::ComPtr<T> out;
+    CHK(in.As(&out));
+    return out;
+}
+
+// Cast an ABI smartpointer
+template<typename T, typename U>
+Microsoft::WRL::ComPtr<T> As(U* in)
+{
+    Microsoft::WRL::ComPtr<T> out;
+    CHK(in->QueryInterface(IID_PPV_ARGS(&out)));
+    return out;
+}
+
+// Get access to bytes in IBuffer
+inline unsigned char* GetData(_In_ WSS::IBuffer^ buffer)
+{
+    unsigned char* bytes = nullptr;
+    CHK(As<WSS::IBufferByteAccess>(buffer)->Buffer(&bytes));
+    return bytes;
+}
+
+// Class to start and shutdown Media Foundation
+class AutoMF
+{
+public:
+    AutoMF()
+        : _bInitialized(false)
+    {
+        CHK(MFStartup(MF_VERSION));
+    }
+
+    ~AutoMF()
+    {
+        if (_bInitialized)
+        {
+            (void)MFShutdown();
+        }
+    }
+
+private:
+    bool _bInitialized;
+};
+
+// Class to track error origin
+template <size_t N>
+HRESULT OriginateError(__in HRESULT hr, __in wchar_t const (&str)[N])
+{
+    if (FAILED(hr))
+    {
+        ::RoOriginateErrorW(hr, N - 1, str);
+    }
+    return hr;
+}
+
+// Class to track error origin
+inline HRESULT OriginateError(__in HRESULT hr)
+{
+    if (FAILED(hr))
+    {
+        ::RoOriginateErrorW(hr, 0, nullptr);
+    }
+    return hr;
+}
+
+// Converts exceptions into HRESULTs
+template <typename Lambda>
+HRESULT ExceptionBoundary(Lambda&& lambda)
+{
+    try
+    {
+        lambda();
+        return S_OK;
+    }
+    catch (Platform::Exception^ e)
+    {
+        return e->HResult;
+    }
+    catch (const std::bad_alloc&)
+    {
+        return E_OUTOFMEMORY;
+    }
+    catch (const std::exception&)
+    {
+        return E_FAIL;
+    }
+}
+
+// Wraps an IMFSample in a C++/CX class to be able to define a callback delegate
+ref class MediaSample sealed
+{
+internal:
+    MW::ComPtr<IMFSample> Sample;
+};
+
+delegate void MediaSampleHandler(MediaSample^ sample);
\ No newline at end of file

modules/videoio/src/cap_winrt/MediaStreamSink.cpp

+// Copyright (c) Microsoft. All rights reserved.
+//
+// The MIT License (MIT)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "MediaStreamSink.hpp"
+#include "MFIncludes.hpp"
+
+using namespace Media;
+using namespace Microsoft::WRL;
+using namespace Platform;
+using namespace Windows::Foundation;
+
+MediaStreamSink::MediaStreamSink(
+    __in const MW::ComPtr<IMFMediaSink>& sink,
+    __in DWORD id,
+    __in const MW::ComPtr<IMFMediaType>& mt,
+    __in MediaSampleHandler^ sampleHandler
+    )
+    : _shutdown(false)
+    , _id(-1)
+    , _width(0)
+    , _height(0)
+{
+    CHK(MFCreateEventQueue(&_eventQueue));
+    CHK(MFCreateMediaType(&_curMT));
+
+    _UpdateMediaType(mt);
+
+    _sink = sink;
+    _id = id;
+    _sampleHandler = sampleHandler;
+}
+
+HRESULT MediaStreamSink::GetMediaSink(__deref_out IMFMediaSink **sink)
+{
+    return ExceptionBoundary([this, sink]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(sink);
+        *sink = nullptr;
+
+        _VerifyNotShutdown();
+
+        CHK(_sink.CopyTo(sink));
+    });
+}
+
+HRESULT MediaStreamSink::GetIdentifier(__out DWORD *identifier)
+{
+    return ExceptionBoundary([this, identifier]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(identifier);
+
+        _VerifyNotShutdown();
+
+        *identifier = _id;
+    });
+}
+
+HRESULT MediaStreamSink::GetMediaTypeHandler(__deref_out IMFMediaTypeHandler **handler)
+{
+    return ExceptionBoundary([this, handler]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(handler);
+        *handler = nullptr;
+
+        _VerifyNotShutdown();
+
+        *handler = this;
+        this->AddRef();
+
+    });
+}
+
+void MediaStreamSink::RequestSample()
+{
+    auto lock = _lock.LockExclusive();
+
+    _VerifyNotShutdown();
+
+    CHK(_eventQueue->QueueEventParamVar(MEStreamSinkRequestSample, GUID_NULL, S_OK, nullptr));
+}
+
+HRESULT MediaStreamSink::ProcessSample(__in_opt IMFSample *sample)
+{
+    return ExceptionBoundary([this, sample]()
+    {
+        MediaSampleHandler^ sampleHandler;
+        auto mediaSample = ref new MediaSample();
+
+        {
+            auto lock = _lock.LockExclusive();
+
+            _VerifyNotShutdown();
+
+            if (sample == nullptr)
+            {
+                return;
+            }
+
+            mediaSample->Sample = sample;
+            sampleHandler = _sampleHandler;
+        }
+
+        // Call back without the lock taken to avoid deadlocks
+        sampleHandler(mediaSample);
+    });
+}
+
+HRESULT MediaStreamSink::PlaceMarker(__in MFSTREAMSINK_MARKER_TYPE /*markerType*/, __in const PROPVARIANT * /*markerValue*/, __in const PROPVARIANT * contextValue)
+{
+    return ExceptionBoundary([this, contextValue]()
+    {
+        auto lock = _lock.LockExclusive();
+        CHKNULL(contextValue);
+
+        _VerifyNotShutdown();
+
+        CHK(_eventQueue->QueueEventParamVar(MEStreamSinkMarker, GUID_NULL, S_OK, contextValue));
+    });
+}
+
+HRESULT MediaStreamSink::Flush()
+{
+    return ExceptionBoundary([this]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        _VerifyNotShutdown();
+    });
+}
+
+HRESULT MediaStreamSink::GetEvent(__in DWORD flags, __deref_out IMFMediaEvent **event)
+{
+    return ExceptionBoundary([this, flags, event]()
+    {
+        CHKNULL(event);
+        *event = nullptr;
+
+        ComPtr<IMFMediaEventQueue> eventQueue;
+
+        {
+            auto lock = _lock.LockExclusive();
+
+            _VerifyNotShutdown();
+
+            eventQueue = _eventQueue;
+        }
+
+        // May block for a while
+        CHK(eventQueue->GetEvent(flags, event));
+    });
+}
+
+HRESULT MediaStreamSink::BeginGetEvent(__in IMFAsyncCallback *callback, __in_opt IUnknown *state)
+{
+    return ExceptionBoundary([this, callback, state]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        _VerifyNotShutdown();
+
+        CHK(_eventQueue->BeginGetEvent(callback, state));
+    });
+}
+
+
+HRESULT MediaStreamSink::EndGetEvent(__in IMFAsyncResult *result, __deref_out IMFMediaEvent **event)
+{
+    return ExceptionBoundary([this, result, event]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(event);
+        *event = nullptr;
+
+        _VerifyNotShutdown();
+
+        CHK(_eventQueue->EndGetEvent(result, event));
+    });
+}
+
+HRESULT MediaStreamSink::QueueEvent(
+    __in MediaEventType met,
+    __in REFGUID extendedType,
+    __in HRESULT status,
+    __in_opt const PROPVARIANT *value
+    )
+{
+    return ExceptionBoundary([this, met, extendedType, status, value]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        _VerifyNotShutdown();
+
+        CHK(_eventQueue->QueueEventParamVar(met, extendedType, status, value));
+    });
+}
+
+HRESULT MediaStreamSink::IsMediaTypeSupported(__in IMFMediaType *mediaType, __deref_out_opt  IMFMediaType **closestMediaType)
+{
+    bool supported = false;
+
+    HRESULT hr = ExceptionBoundary([this, mediaType, closestMediaType, &supported]()
+    {
+        auto lock = _lock.LockExclusive();
+        HRESULT hr = S_OK;
+
+        if (closestMediaType != nullptr)
+        {
+            *closestMediaType = nullptr;
+        }
+
+        CHKNULL(mediaType);
+
+        _VerifyNotShutdown();
+
+        supported = _IsMediaTypeSupported(mediaType);
+    });
+
+    // Avoid throwing an exception to return MF_E_INVALIDMEDIATYPE as this is not a exceptional case
+    return FAILED(hr) ? hr : supported ? S_OK : MF_E_INVALIDMEDIATYPE;
+}
+
+HRESULT MediaStreamSink::GetMediaTypeCount(__out DWORD *typeCount)
+{
+    return ExceptionBoundary([this, typeCount]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(typeCount);
+
+        _VerifyNotShutdown();
+
+        // No media type provided by default (app needs to specify it)
+        *typeCount = 0;
+    });
+}
+
+HRESULT MediaStreamSink::GetMediaTypeByIndex(__in DWORD /*index*/, __deref_out  IMFMediaType **mediaType)
+{
+    HRESULT hr = ExceptionBoundary([this, mediaType]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(mediaType);
+        *mediaType = nullptr;
+
+        _VerifyNotShutdown();
+    });
+
+    // Avoid throwing an exception to return MF_E_NO_MORE_TYPES as this is not a exceptional case
+    return FAILED(hr) ? hr : MF_E_NO_MORE_TYPES;
+}
+
+HRESULT MediaStreamSink::SetCurrentMediaType(__in IMFMediaType *mediaType)
+{
+    return ExceptionBoundary([this, mediaType]()
+    {
+        auto lock = _lock.LockExclusive();
+        HRESULT hr = S_OK;
+
+        CHKNULL(mediaType);
+
+        _VerifyNotShutdown();
+
+        if (!_IsMediaTypeSupported(mediaType))
+        {
+            CHK(MF_E_INVALIDMEDIATYPE);
+        }
+
+        _UpdateMediaType(mediaType);
+    });
+}
+
+HRESULT MediaStreamSink::GetCurrentMediaType(__deref_out_opt IMFMediaType **mediaType)
+{
+    return ExceptionBoundary([this, mediaType]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(mediaType);
+        *mediaType = nullptr;
+
+        _VerifyNotShutdown();
+
+        ComPtr<IMFMediaType> mt;
+        CHK(MFCreateMediaType(&mt));
+        CHK(_curMT->CopyAllItems(mt.Get()));
+        *mediaType = mt.Detach();
+    });
+}
+
+HRESULT MediaStreamSink::GetMajorType(__out GUID *majorType)
+{
+    return ExceptionBoundary([this, majorType]()
+    {
+        auto lock = _lock.LockExclusive();
+
+        CHKNULL(majorType);
+
+        _VerifyNotShutdown();
+
+        *majorType = _majorType;
+    });
+}
+
+void MediaStreamSink::InternalSetCurrentMediaType(__in const ComPtr<IMFMediaType>& mediaType)
+{
+    auto lock = _lock.LockExclusive();
+
+    CHKNULL(mediaType);
+
+    _VerifyNotShutdown();
+
+    _UpdateMediaType(mediaType);
+}
+
+void MediaStreamSink::Shutdown()
+{
+    auto lock = _lock.LockExclusive();
+
+    if (_shutdown)
+    {
+        return;
+    }
+    _shutdown = true;
+
+    (void)_eventQueue->Shutdown();
+    _eventQueue = nullptr;
+
+    _curMT = nullptr;
+    _sink = nullptr;
+    _sampleHandler = nullptr;
+}
+
+bool MediaStreamSink::_IsMediaTypeSupported(__in const ComPtr<IMFMediaType>& mt) const
+{
+    GUID majorType;
+    GUID subType;
+    if (SUCCEEDED(mt->GetGUID(MF_MT_MAJOR_TYPE, &majorType)) &&
+        SUCCEEDED(mt->GetGUID(MF_MT_SUBTYPE, &subType)) &&
+        (majorType == _majorType) &&
+        (subType == _subType))
+    {
+        return true;
+    }
+
+    return false;
+}
+
+void MediaStreamSink::_UpdateMediaType(__in const ComPtr<IMFMediaType>& mt)
+{
+    CHK(mt->GetGUID(MF_MT_MAJOR_TYPE, &_majorType));
+    CHK(mt->GetGUID(MF_MT_SUBTYPE, &_subType));
+
+    if (_majorType == MFMediaType_Video)
+    {
+        CHK(MFGetAttributeSize(mt.Get(), MF_MT_FRAME_SIZE, &_width, &_height));
+    }
+
+    CHK(mt->CopyAllItems(_curMT.Get()));
+}
\ No newline at end of file

modules/videoio/src/cap_winrt/MediaStreamSink.hpp

+// Copyright (c) Microsoft. All rights reserved.
+//
+// The MIT License (MIT)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#pragma once
+
+#include "MFIncludes.hpp"
+
+namespace Media {
+
+class MediaStreamSink WrlSealed :
+    public Microsoft::WRL::RuntimeClass<
+    Microsoft::WRL::RuntimeClassFlags<Microsoft::WRL::ClassicCom>,
+    IMFStreamSink,
+    IMFMediaEventGenerator,
+    IMFMediaTypeHandler
+    >
+{
+public:
+
+    MediaStreamSink(
+        __in const MW::ComPtr<IMFMediaSink>& sink,
+        __in DWORD id,
+        __in const MW::ComPtr<IMFMediaType>& mt,
+        __in MediaSampleHandler^ sampleHandler
+    );
+
+    //
+    // IMFStreamSink
+    //
+
+    IFACEMETHODIMP GetMediaSink(__deref_out IMFMediaSink **sink);
+    IFACEMETHODIMP GetIdentifier(__out DWORD *identifier);
+    IFACEMETHODIMP GetMediaTypeHandler(__deref_out IMFMediaTypeHandler **handler);
+    IFACEMETHODIMP ProcessSample(__in_opt IMFSample *sample);
+    IFACEMETHODIMP PlaceMarker(__in MFSTREAMSINK_MARKER_TYPE markerType, __in const PROPVARIANT * markerValue, __in const PROPVARIANT * contextValue);
+    IFACEMETHODIMP Flush();
+
+    //
+    // IMFMediaEventGenerator
+    //
+
+    IFACEMETHODIMP GetEvent(__in DWORD flags, __deref_out IMFMediaEvent **event);
+    IFACEMETHODIMP BeginGetEvent(__in IMFAsyncCallback *callback, __in_opt IUnknown *state);
+    IFACEMETHODIMP EndGetEvent(__in IMFAsyncResult *result, __deref_out IMFMediaEvent **event);
+    IFACEMETHODIMP QueueEvent(__in MediaEventType met, __in REFGUID extendedType, __in HRESULT status, __in_opt const PROPVARIANT *value);
+
+    //
+    // IMFMediaTypeHandler
+    //
+
+    IFACEMETHODIMP IsMediaTypeSupported(__in IMFMediaType *mediaType, __deref_out_opt  IMFMediaType **closestMediaType);
+    IFACEMETHODIMP GetMediaTypeCount(__out DWORD *typeCount);
+    IFACEMETHODIMP GetMediaTypeByIndex(__in DWORD index, __deref_out  IMFMediaType **mediaType);
+    IFACEMETHODIMP SetCurrentMediaType(__in IMFMediaType *mediaType);
+    IFACEMETHODIMP GetCurrentMediaType(__deref_out_opt IMFMediaType **mediaType);
+    IFACEMETHODIMP GetMajorType(__out GUID *majorType);
+
+    //
+    // Misc
+    //
+
+    void InternalSetCurrentMediaType(__in const MW::ComPtr<IMFMediaType>& mediaType);
+    void RequestSample();
+    void Shutdown();
+
+private:
+
+    bool _IsMediaTypeSupported(__in const MW::ComPtr<IMFMediaType>& mt) const;
+    void _UpdateMediaType(__in const MW::ComPtr<IMFMediaType>& mt);
+
+    void _VerifyNotShutdown()
+    {
+        if (_shutdown)
+        {
+            CHK(MF_E_SHUTDOWN);
+        }
+    }
+
+    MW::ComPtr<IMFMediaSink> _sink;
+    MW::ComPtr<IMFMediaEventQueue> _eventQueue;
+    MW::ComPtr<IMFMediaType> _curMT;
+
+    MediaSampleHandler^ _sampleHandler;
+
+    GUID _majorType;
+    GUID _subType;
+    unsigned int _width;
+    unsigned int _height;
+    DWORD _id;
+    bool _shutdown;
+
+    MWW::SRWLock _lock;
+};
+
+}
\ No newline at end of file

modules/videoio/src/cap_winrt_bridge.cpp

+// videoio to XAML bridge for OpenCV
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#include "opencv2\videoio\cap_winrt.hpp"
+#include "cap_winrt_capture.hpp"
+#include "cap_winrt_bridge.hpp"
+#include "cap_winrt_video.hpp"
+
+using namespace Windows::Foundation;
+using namespace Windows::Media::Capture;
+using namespace Windows::Media::MediaProperties;
+using namespace Windows::Devices::Enumeration;
+
+using namespace Windows::UI::Xaml::Media::Imaging;
+using namespace Microsoft::WRL;
+
+using namespace Platform;
+using namespace ::Concurrency;
+
+using namespace ::std;
+
+/***************************** VideoioBridge class ******************************/
+
+// non-blocking
+void VideoioBridge::requestForUIthreadAsync(int action, int widthp, int heightp)
+{
+    reporter.report(action);
+}
+
+VideoioBridge& VideoioBridge::getInstance()
+{
+    static VideoioBridge instance;
+    return instance;
+}
+
+void VideoioBridge::swapInputBuffers()
+{
+    // TODO: already locked, check validity
+    // lock_guard<mutex> lock(inputBufferMutex);
+    swap(backInputPtr, frontInputPtr);
+    //if (currentFrame != frameCounter)
+    //{
+    //    currentFrame = frameCounter;
+    //    swap(backInputPtr, frontInputPtr);
+    //}
+}
+
+void VideoioBridge::swapOutputBuffers()
+{
+    lock_guard<mutex> lock(outputBufferMutex);
+    swap(frontOutputBuffer, backOutputBuffer);
+}
+
+void VideoioBridge::allocateOutputBuffers()
+{
+    frontOutputBuffer = ref new WriteableBitmap(width, height);
+    backOutputBuffer = ref new WriteableBitmap(width, height);
+}
+
+void VideoioBridge::imshow()
+{
+    VideoioBridge::getInstance().swapOutputBuffers();
+    VideoioBridge::getInstance().requestForUIthreadAsync(cv::UPDATE_IMAGE_ELEMENT);
+}
+
+// end
\ No newline at end of file

modules/videoio/src/cap_winrt_bridge.hpp

+// videoio to XAML bridge for OpenCV
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+// this header is included in the XAML App, so it cannot include any
+// OpenCV headers, or a static assert will be raised
+
+#include <ppl.h>
+#include <ppltasks.h>
+#include <concrt.h>
+#include <agile.h>
+#include <opencv2\core.hpp>
+
+#include <mutex>
+#include <memory>
+#include <atomic>
+#include <functional>
+
+
+// Class VideoioBridge (singleton) is needed because the interface for
+// VideoCapture_WinRT in cap_winrt_capture.hpp is fixed by OpenCV.
+class VideoioBridge
+{
+public:
+
+    static VideoioBridge& getInstance();
+
+    // call after initialization
+    void setReporter(Concurrency::progress_reporter<int> pr) { reporter = pr; }
+
+    // to be called from cvMain via cap_winrt on bg thread - non-blocking (async)
+    void requestForUIthreadAsync( int action, int width=0, int height=0 );
+
+    // TODO: modify in window.cpp: void cv::imshow( const String& winname, InputArray _img )
+    void    imshow(/*cv::InputArray matToShow*/);   // shows Mat in the cvImage element
+    void    swapInputBuffers();
+    void    allocateOutputBuffers();
+    void    swapOutputBuffers();
+
+
+    int                         deviceIndex, width, height;
+    std::atomic<bool>           bIsFrameNew;
+    std::mutex                  inputBufferMutex;   // input is double buffered
+    unsigned char *             frontInputPtr;      // OpenCV reads this
+    unsigned char *             backInputPtr;       // Video grabber writes this
+    std::atomic<unsigned long>  frameCounter;
+    unsigned long               currentFrame;
+
+    std::mutex                  outputBufferMutex;  // output is double buffered
+    Windows::UI::Xaml::Media::Imaging::WriteableBitmap^ frontOutputBuffer;  // OpenCV write this
+    Windows::UI::Xaml::Media::Imaging::WriteableBitmap^ backOutputBuffer;   // XAML reads this
+    Windows::UI::Xaml::Controls::Image ^cvImage;
+
+private:
+
+    VideoioBridge() {
+        deviceIndex = 0;
+        width = 640;
+        height = 480;
+        deviceReady = false;
+        bIsFrameNew = false;
+        currentFrame = 0;
+        frameCounter = 0;
+    };
+
+    // singleton
+    VideoioBridge(VideoioBridge const &);
+    void operator=(const VideoioBridge &);
+
+    std::atomic<bool>   deviceReady;
+    Concurrency::progress_reporter<int> reporter;
+};
\ No newline at end of file

modules/videoio/src/cap_winrt_capture.cpp

+// Capture support for WinRT
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+
+#include "precomp.hpp"
+#include "cap_winrt_capture.hpp"
+#include "cap_winrt_bridge.hpp"
+#include "cap_winrt_video.hpp"
+#include <opencv2\videoio\cap_winrt.hpp>
+
+using namespace Windows::Foundation;
+using namespace Windows::Media::Capture;
+using namespace Windows::Media::MediaProperties;
+using namespace Windows::Devices::Enumeration;
+
+using namespace Platform;
+
+using namespace Windows::UI::Xaml::Media::Imaging;
+using namespace Microsoft::WRL;
+
+using namespace ::std;
+
+
+// nb. VideoCapture_WinRT is not a singleton, so the Mats are made file statics
+// we do not support more than one capture device simultaneously with the
+// design at this time
+
+// nb. inputBufferMutex was not able to guarantee that OpenCV Mats were
+// ready to accept data in the UI thread (memory access exceptions were thrown
+// even though buffer address was good).
+// Therefore allocation of Mats is also done on the UI thread before the video
+// device is initialized.
+
+static cv::Mat frontInputMat;
+static cv::Mat backInputMat;
+
+namespace cv {
+
+    /***************************** exported control functions ******************************/
+
+    template <typename ...Args>
+    void winrt_startMessageLoop(std::function<void(Args...)>&& callback, Args... args)
+    {
+        auto asyncTask = ::concurrency::create_async([=](::concurrency::progress_reporter<int> reporter)
+        {
+            VideoioBridge::getInstance().setReporter(reporter);
+
+            // frame reading loop
+            callback(args...);
+        });
+
+        asyncTask->Progress = ref new AsyncActionProgressHandler<int>([=](IAsyncActionWithProgress<int>^ act, int progress)
+        {
+            int action = progress;
+
+            // these actions will be processed on the UI thread asynchronously
+            switch (action)
+            {
+            case OPEN_CAMERA:
+                winrt_openCamera();
+                break;
+            case CLOSE_CAMERA:
+                winrt_closeGrabber();
+                break;
+            case UPDATE_IMAGE_ELEMENT:
+                winrt_updateFrameContainer();
+                break;
+            }
+        });
+    }
+
+    template <typename ...Args>
+    void winrt_startMessageLoop(void callback(Args...), Args... args)
+    {
+        winrt_startMessageLoop(std::function<void(Args...)>(callback), args...);
+    }
+
+    void winrt_onVisibilityChanged(bool visible) {
+        if (visible)
+        {
+            VideoioBridge& bridge = VideoioBridge::getInstance();
+
+            // only start the grabber if the camera was opened in OpenCV
+            if (bridge.backInputPtr != nullptr)
+            {
+                if (Video::getInstance().isStarted()) return;
+
+                int device = bridge.deviceIndex;
+                int width = bridge.width;
+                int height = bridge.height;
+
+                winrt_initGrabber(device, width, height);
+            }
+        } else
+        {
+            //grabberStarted = false;
+            winrt_closeGrabber();
+        }
+    }
+
+    void winrt_imshow() {
+        VideoioBridge::getInstance().imshow();
+    }
+
+    void winrt_setFrameContainer(::Windows::UI::Xaml::Controls::Image^ image) {
+        VideoioBridge::getInstance().cvImage = image;
+    }
+
+
+    /********************************* Internal helpers ************************************/
+
+    void winrt_updateFrameContainer()
+    {
+        // copy output Mat to WBM
+        winrt_copyOutput();
+
+        // set XAML image element with image WBM
+        VideoioBridge::getInstance().cvImage->Source = VideoioBridge::getInstance().backOutputBuffer;
+    }
+
+    // performed on UI thread
+    bool winrt_openCamera()
+    {
+        VideoioBridge& bridge = VideoioBridge::getInstance();
+
+        int device = bridge.deviceIndex;
+        int width = bridge.width;
+        int height = bridge.height;
+
+        // buffers must alloc'd on UI thread
+        winrt_allocateBuffers(width, height);
+
+        // nb. video capture device init must be done on UI thread;
+        if (!Video::getInstance().isStarted())
+        {
+            winrt_initGrabber(device, width, height);
+            return true;
+        }
+
+        return false;
+    }
+
+    // performed on UI thread
+    void winrt_allocateBuffers(int width, int height)
+    {
+        VideoioBridge& bridge = VideoioBridge::getInstance();
+
+        // allocate input Mats (bgra8 = CV_8UC4, RGB24 = CV_8UC3)
+        frontInputMat.create(height, width, CV_8UC3);
+        backInputMat.create(height, width, CV_8UC3);
+
+        bridge.frontInputPtr = frontInputMat.ptr(0);
+        bridge.backInputPtr = backInputMat.ptr(0);
+
+        bridge.allocateOutputBuffers();
+    }
+
+    // non-blocking
+    bool winrt_initGrabber(int device, int w, int h) {
+        // nb. Video class is not exported outside of this DLL
+        // due to complexities in the CaptureFrameGrabber ref class
+        // as written in the header not mixing well with pure C++ classes
+        return Video::getInstance().initGrabber(device, w, h);
+    }
+
+    void winrt_closeGrabber() {
+        Video::getInstance().closeGrabber();
+    }
+
+    // nb on UI thread
+    void winrt_copyOutput() {
+        Video::getInstance().CopyOutput();
+    }
+
+
+    /********************************* VideoCapture_WinRT class ****************************/
+
+    VideoCapture_WinRT::VideoCapture_WinRT(int device) : started(false)
+    {
+        VideoioBridge::getInstance().deviceIndex = device;
+    }
+
+    bool VideoCapture_WinRT::isOpened() const
+    {
+        return true; // started;
+    }
+
+    // grab a frame:
+    // this will NOT block per spec
+    // should be called on the image processing thread, not the UI thread
+    bool VideoCapture_WinRT::grabFrame()
+    {
+        // if device is not started we must return true so retrieveFrame() is called to start device
+        // nb. we cannot start the device here because we do not know the size of the input Mat
+        if (!started) return true;
+
+        if (VideoioBridge::getInstance().bIsFrameNew)
+        {
+            return true;
+        }
+
+        // nb. if blocking is to be added:
+        // unique_lock<mutex> lock(VideoioBridge::getInstance().frameReadyMutex);
+        // VideoioBridge::getInstance().frameReadyEvent.wait(lock);
+        return false;
+    }
+
+    // should be called on the image processing thread after grabFrame
+    // see VideoCapture::read
+    bool VideoCapture_WinRT::retrieveFrame(int channel, cv::OutputArray outArray)
+    {
+        if (!started) {
+
+            int width, height;
+            width = outArray.size().width;
+            height = outArray.size().height;
+            if (width == 0) width = 640;
+            if (height == 0) height = 480;
+
+            VideoioBridge::getInstance().width = width;
+            VideoioBridge::getInstance().height = height;
+
+            // nb. Mats will be alloc'd on UI thread
+
+            // request device init on UI thread - this does not block, and is async
+            VideoioBridge::getInstance().requestForUIthreadAsync(OPEN_CAMERA,
+                outArray.size().width, outArray.size().height);
+
+            started = true;
+            return false;
+        }
+
+        if (!started) return false;
+
+        return VideoioBridge::getInstance().bIsFrameNew;
+    }
+
+
+    bool VideoCapture_WinRT::setProperty(int property_id, double value)
+    {
+        switch (property_id)
+        {
+        case CAP_PROP_FRAME_WIDTH:
+            size.width = (int)value;
+            break;
+        case CAP_PROP_FRAME_HEIGHT:
+            size.height = (int)value;
+            break;
+        default:
+            return false;
+        }
+        return true;
+    }
+}
+
+// end
\ No newline at end of file

modules/videoio/src/cap_winrt_capture.hpp

+// Capture support for WinRT
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include "precomp.hpp"
+
+#include <mutex>
+#include <memory>
+#include <condition_variable>
+#include <atomic>
+
+#include <agile.h>
+
+
+// nb. implemented the newer IVideoCapture C++ interface so that we can work
+// directly with Mat, not the older C cv interface
+// (which may have added overhead for IPL file conversion)
+
+namespace cv {
+
+    /******************* Internal helpers **************************************/
+
+    void winrt_updateFrameContainer();
+    bool winrt_openCamera();
+    bool winrt_initGrabber(int device, int w, int h);
+    void winrt_closeGrabber();
+    void winrt_copyOutput();
+    void winrt_allocateBuffers(int width, int height);
+
+    /******************* VideoCapture_WinRT class ******************************/
+
+    class VideoCapture_WinRT : public IVideoCapture
+    {
+    public:
+        VideoCapture_WinRT() : started(false) {}
+        VideoCapture_WinRT(int device);
+        virtual ~VideoCapture_WinRT() {}
+
+        // from base class IVideoCapture
+        virtual double getProperty(int) { return 0; }
+        virtual bool setProperty(int, double);
+        virtual bool grabFrame();
+        virtual bool retrieveFrame(int channel, cv::OutputArray outArray);
+
+        // Return the type of the capture object
+        virtual int getCaptureDomain() { return CAP_WINRT; }
+
+        virtual bool isOpened() const;
+
+    protected:
+
+        bool                    started;
+        CvSize                  size;
+        int                     bytesPerPixel;
+        unsigned long           frameCurrent;
+        std::atomic<bool>       isFrameNew;
+    };
+}
\ No newline at end of file

modules/videoio/src/cap_winrt_video.hpp

+// Video support with XAML
+
+// Copyright (c) Microsoft Open Technologies, Inc.
+// All rights reserved.
+//
+// (3 - clause BSD License)
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted provided that
+// the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
+// following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+// following disclaimer in the documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or
+// promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED.IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include "cap_winrt/CaptureFrameGrabber.hpp"
+
+#include <mutex>
+#include <memory>
+
+class Video {
+public:
+
+    bool initGrabber(int device, int w, int h);
+    void closeGrabber();
+    bool isStarted();
+
+    // singleton
+    static Video &getInstance();
+
+    void CopyOutput();
+
+private:
+    // singleton
+    Video();
+
+    void _GrabFrameAsync(::Media::CaptureFrameGrabber^ frameGrabber);
+
+    bool listDevices();
+
+    Platform::Agile<Windows::Media::Capture::MediaCapture> m_capture;
+    Platform::Agile<Windows::Devices::Enumeration::DeviceInformationCollection> m_devices;
+
+    ::Media::CaptureFrameGrabber^ m_frameGrabber;
+
+    bool listDevicesTask();
+
+    bool					bChooseDevice;
+    bool 					bVerbose;
+    bool                    bFlipImageX;
+    //std::atomic<bool>       bGrabberInited;
+    int						m_deviceID;
+    int						attemptFramerate;
+    std::atomic<bool>       bIsFrameNew;
+    std::atomic<bool>       bGrabberInited;
+    std::atomic<bool>       bGrabberInitInProgress;
+    unsigned int			width, height;
+    int                     bytesPerPixel;
+
+};
\ No newline at end of file