interoperability OpenVX samples added

samples/CMakeLists.txt

@@ -22,6 +22,10 @@ if((NOT ANDROID) AND HAVE_OPENGL)
   add_subdirectory(opengl)
 endif()
 
+if(HAVE_OPENVX)
+  add_subdirectory(openvx)
+endif()
+
 if(UNIX AND NOT ANDROID AND (HAVE_VA OR HAVE_VA_INTEL))
   add_subdirectory(va_intel)
 endif()

samples/openvx/CMakeLists.txt

+cmake_minimum_required(VERSION 2.8.9)
+
+set(OPENCV_OPENVX_SAMPLE_REQUIRED_DEPS opencv_core opencv_imgproc opencv_imgcodecs opencv_videoio opencv_highgui)
+
+ocv_check_dependencies(${OPENCV_OPENVX_SAMPLE_REQUIRED_DEPS})
+
+if(BUILD_EXAMPLES AND OCV_DEPENDENCIES_FOUND)
+  set(group "openvx")
+  set(name_wrapped "interop")
+  set(name_orig "interop_orig")
+  set(name_video "interop_video")
+
+  project("${group}_sample")
+
+  ocv_include_modules_recurse(${OPENCV_OPENVX_SAMPLE_REQUIRED_DEPS})
+
+  add_definitions(-DIVX_USE_OPENCV)
+
+  file(GLOB srcs_wrapped wrappers.cpp *.hpp)
+  file(GLOB srcs_orig  no_wrappers.cpp *.hpp)
+  file(GLOB srcs_video wrappers_video.cpp *.hpp)
+
+  MACRO(OPENVX_DEFINE_SAMPLE name srcs)
+    set(target "example_${group}_${name}")
+	add_executable(${target} ${srcs})
+    ocv_target_link_libraries(${target} ${OPENCV_LINKER_LIBS} ${OPENCV_OPENVX_SAMPLE_REQUIRED_DEPS} ${OPENVX_LIBRARIES})
+    if(ENABLE_SOLUTION_FOLDERS)
+        set_target_properties(${target} PROPERTIES FOLDER "samples//${group}")
+    endif()
+  ENDMACRO()
+
+  OPENVX_DEFINE_SAMPLE(${name_wrapped} ${srcs_wrapped})
+  OPENVX_DEFINE_SAMPLE(${name_orig} ${srcs_orig})
+  OPENVX_DEFINE_SAMPLE(${name_video} ${srcs_video})
+
+endif()

samples/openvx/no_wrappers.cpp

+#include <iostream>
+#include <stdexcept>
+
+//OpenVX includes
+#include <VX/vx.h>
+
+//OpenCV includes
+#include "opencv2/core.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/imgcodecs.hpp"
+#include "opencv2/highgui.hpp"
+
+#ifndef VX_VERSION_1_1
+const vx_enum VX_IMAGE_FORMAT = VX_IMAGE_ATTRIBUTE_FORMAT;
+const vx_enum VX_IMAGE_WIDTH  = VX_IMAGE_ATTRIBUTE_WIDTH;
+const vx_enum VX_IMAGE_HEIGHT = VX_IMAGE_ATTRIBUTE_HEIGHT;
+const vx_enum VX_MEMORY_TYPE_HOST = VX_IMPORT_TYPE_HOST;
+const vx_enum VX_MEMORY_TYPE_NONE = VX_IMPORT_TYPE_NONE;
+const vx_enum VX_THRESHOLD_THRESHOLD_VALUE = VX_THRESHOLD_ATTRIBUTE_THRESHOLD_VALUE;
+const vx_enum VX_THRESHOLD_THRESHOLD_LOWER = VX_THRESHOLD_ATTRIBUTE_THRESHOLD_LOWER;
+const vx_enum VX_THRESHOLD_THRESHOLD_UPPER = VX_THRESHOLD_ATTRIBUTE_THRESHOLD_UPPER;
+typedef uintptr_t vx_map_id;
+#endif
+
+enum UserMemoryMode
+{
+    COPY, MAP_TO_VX
+};
+
+vx_image convertCvMatToVxImage(vx_context context, cv::Mat image, bool toCopy)
+{
+    if (!(!image.empty() && image.dims <= 2 && image.channels() == 1))
+        throw std::runtime_error("Invalid format");
+
+    vx_uint32 width  = image.cols;
+    vx_uint32 height = image.rows;
+
+    vx_df_image color;
+    switch (image.depth())
+    {
+    case CV_8U:
+        color = VX_DF_IMAGE_U8;
+        break;
+    case CV_16U:
+        color = VX_DF_IMAGE_U16;
+        break;
+    case CV_16S:
+        color = VX_DF_IMAGE_S16;
+        break;
+    case CV_32S:
+        color = VX_DF_IMAGE_S32;
+        break;
+    default:
+        throw std::runtime_error("Invalid format");
+        break;
+    }
+
+    vx_imagepatch_addressing_t addr;
+    addr.dim_x = width;
+    addr.dim_y = height;
+    addr.stride_x = (vx_uint32)image.elemSize();
+    addr.stride_y = (vx_uint32)image.step.p[0];
+    vx_uint8* ovxData = image.data;
+
+    vx_image ovxImage;
+    if (toCopy)
+    {
+        ovxImage = vxCreateImage(context, width, height, color);
+        if (vxGetStatus((vx_reference)ovxImage) != VX_SUCCESS)
+            throw std::runtime_error("Failed to create image");
+        vx_rectangle_t rect;
+
+        vx_status status = vxGetValidRegionImage(ovxImage, &rect);
+        if (status != VX_SUCCESS)
+            throw std::runtime_error("Failed to get valid region");
+
+#ifdef VX_VERSION_1_1
+        status = vxCopyImagePatch(ovxImage, &rect, 0, &addr, ovxData, VX_WRITE_ONLY, VX_MEMORY_TYPE_HOST);
+        if (status != VX_SUCCESS)
+            throw std::runtime_error("Failed to copy image patch");
+#else
+        status = vxAccessImagePatch(ovxImage, &rect, 0, &addr, (void**)&ovxData, VX_WRITE_ONLY);
+        if (status != VX_SUCCESS)
+            throw std::runtime_error("Failed to access image patch");
+        status = vxCommitImagePatch(ovxImage, &rect, 0, &addr, ovxData);
+        if (status != VX_SUCCESS)
+            throw std::runtime_error("Failed to commit image patch");
+#endif
+    }
+    else
+    {
+#ifdef VX_VERSION_1_1
+        ovxImage = vxCreateImageFromHandle(context, color, &addr, (void*const*)&ovxData, VX_MEMORY_TYPE_HOST);
+#else
+        ovxImage = vxCreateImageFromHandle(context, color, &addr, (void**)&ovxData, VX_MEMORY_TYPE_HOST);
+#endif
+        if (vxGetStatus((vx_reference)ovxImage) != VX_SUCCESS)
+            throw std::runtime_error("Failed to create image from handle");
+    }
+
+    return ovxImage;
+}
+
+
+cv::Mat copyVxImageToCvMat(vx_image ovxImage)
+{
+    vx_status status;
+    vx_df_image df_image = 0;
+    vx_uint32 width, height;
+    status = vxQueryImage(ovxImage, VX_IMAGE_FORMAT, &df_image, sizeof(vx_df_image));
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to query image");
+    status = vxQueryImage(ovxImage, VX_IMAGE_WIDTH, &width, sizeof(vx_uint32));
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to query image");
+    status = vxQueryImage(ovxImage, VX_IMAGE_HEIGHT, &height, sizeof(vx_uint32));
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to query image");
+
+    if (!(width > 0 && height > 0)) throw std::runtime_error("Invalid format");
+
+    int depth;
+    switch (df_image)
+    {
+    case VX_DF_IMAGE_U8:
+        depth = CV_8U;
+        break;
+    case VX_DF_IMAGE_U16:
+        depth = CV_16U;
+        break;
+    case VX_DF_IMAGE_S16:
+        depth = CV_16S;
+        break;
+    case VX_DF_IMAGE_S32:
+        depth = CV_32S;
+        break;
+    default:
+        throw std::runtime_error("Invalid format");
+        break;
+    }
+
+    cv::Mat image(height, width, CV_MAKE_TYPE(depth, 1));
+
+    vx_rectangle_t rect;
+    rect.start_x = rect.start_y = 0;
+    rect.end_x = width; rect.end_y = height;
+
+    vx_imagepatch_addressing_t addr;
+    addr.dim_x = width;
+    addr.dim_y = height;
+    addr.stride_x = (vx_uint32)image.elemSize();
+    addr.stride_y = (vx_uint32)image.step.p[0];
+    vx_uint8* matData = image.data;
+
+#ifdef VX_VERSION_1_1
+    status = vxCopyImagePatch(ovxImage, &rect, 0, &addr, matData, VX_READ_ONLY, VX_MEMORY_TYPE_HOST);
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to copy image patch");
+#else
+    status = vxAccessImagePatch(ovxImage, &rect, 0, &addr, (void**)&matData, VX_READ_ONLY);
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to access image patch");
+    status = vxCommitImagePatch(ovxImage, &rect, 0, &addr, matData);
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to commit image patch");
+#endif
+
+    return image;
+}
+
+
+void swapVxImage(vx_image ovxImage)
+{
+#ifdef VX_VERSION_1_1
+    vx_status status;
+    vx_memory_type_e memType;
+    status = vxQueryImage(ovxImage, VX_IMAGE_MEMORY_TYPE, &memType, sizeof(vx_memory_type_e));
+    if (status != VX_SUCCESS)
+        throw std::runtime_error("Failed to query image");
+    if (memType == VX_MEMORY_TYPE_NONE)
+    {
+        //was created by copying user data
+        throw std::runtime_error("Image wasn't created from user handle");
+    }
+    else
+    {
+        //was created from user handle
+        status = vxSwapImageHandle(ovxImage, NULL, NULL, 0);
+        if (status != VX_SUCCESS)
+            throw std::runtime_error("Failed to swap image handle");
+    }
+#else
+    //not supported until OpenVX 1.1
+    (void) ovxImage;
+#endif
+}
+
+
+vx_status createProcessingGraph(vx_image inputImage, vx_image outputImage, vx_graph& graph)
+{
+    vx_status status;
+    vx_context context = vxGetContext((vx_reference)inputImage);
+    status = vxGetStatus((vx_reference)context);
+    if(status != VX_SUCCESS) return status;
+
+    graph = vxCreateGraph(context);
+    status = vxGetStatus((vx_reference)graph);
+    if (status != VX_SUCCESS) return status;
+
+    vx_uint32 width, height;
+    status = vxQueryImage(inputImage, VX_IMAGE_WIDTH, &width, sizeof(vx_uint32));
+    if (status != VX_SUCCESS) return status;
+    status = vxQueryImage(inputImage, VX_IMAGE_HEIGHT, &height, sizeof(vx_uint32));
+    if (status != VX_SUCCESS) return status;
+
+    // Intermediate images
+    vx_image
+        smoothed  = vxCreateVirtualImage(graph, 0, 0, VX_DF_IMAGE_VIRT),
+        cannied   = vxCreateVirtualImage(graph, 0, 0, VX_DF_IMAGE_VIRT),
+        halfImg   = vxCreateImage(context, width, height, VX_DF_IMAGE_U8),
+        halfCanny = vxCreateImage(context, width, height, VX_DF_IMAGE_U8);
+
+    vx_image virtualImages[] = {smoothed, cannied, halfImg, halfCanny};
+    for(size_t i = 0; i < sizeof(virtualImages)/sizeof(vx_image); i++)
+    {
+        status = vxGetStatus((vx_reference)virtualImages[i]);
+        if (status != VX_SUCCESS) return status;
+    }
+
+    // Constants
+    vx_uint32 threshValue = 50;
+    vx_threshold thresh = vxCreateThreshold(context, VX_THRESHOLD_TYPE_BINARY, VX_TYPE_UINT8);
+    vxSetThresholdAttribute(thresh, VX_THRESHOLD_THRESHOLD_VALUE,
+                            &threshValue, sizeof(threshValue));
+
+    vx_uint32 threshCannyMin = 127;
+    vx_uint32 threshCannyMax = 192;
+    vx_threshold threshCanny = vxCreateThreshold(context, VX_THRESHOLD_TYPE_RANGE, VX_TYPE_UINT8);
+    vxSetThresholdAttribute(threshCanny, VX_THRESHOLD_THRESHOLD_LOWER, &threshCannyMin,
+                            sizeof(threshCannyMin));
+    vxSetThresholdAttribute(threshCanny, VX_THRESHOLD_THRESHOLD_UPPER, &threshCannyMax,
+                            sizeof(threshCannyMax));
+    vx_float32 alphaValue = 0.5;
+    vx_scalar alpha = vxCreateScalar(context, VX_TYPE_FLOAT32, &alphaValue);
+
+    // Sequence of meaningless image operations
+    vx_node nodes[] = {
+        vxGaussian3x3Node(graph, inputImage, smoothed),
+        vxCannyEdgeDetectorNode(graph, smoothed, threshCanny, 3, VX_NORM_L2, cannied),
+        vxAccumulateWeightedImageNode(graph, inputImage, alpha, halfImg),
+        vxAccumulateWeightedImageNode(graph, cannied, alpha, halfCanny),
+        vxAddNode(graph, halfImg, halfCanny, VX_CONVERT_POLICY_SATURATE, outputImage)
+    };
+
+    for (size_t i = 0; i < sizeof(nodes) / sizeof(vx_node); i++)
+    {
+        status = vxGetStatus((vx_reference)nodes[i]);
+        if (status != VX_SUCCESS) return status;
+    }
+
+    status = vxVerifyGraph(graph);
+    return status;
+}
+
+
+int ovxDemo(std::string inputPath, UserMemoryMode mode)
+{
+    cv::Mat image = cv::imread(inputPath, cv::IMREAD_GRAYSCALE);
+    if (image.empty()) return -1;
+
+    //check image format
+    if (image.depth() != CV_8U || image.channels() != 1) return -1;
+
+    vx_status status;
+    vx_context context = vxCreateContext();
+    status = vxGetStatus((vx_reference)context);
+    if (status != VX_SUCCESS) return status;
+
+    //put user data from cv::Mat to vx_image
+    vx_image ovxImage;
+    ovxImage = convertCvMatToVxImage(context, image, mode == COPY);
+
+    vx_uint32 width = image.cols, height = image.rows;
+
+    vx_image ovxResult;
+    cv::Mat output;
+    if (mode == COPY)
+    {
+        //we will copy data from vx_image to cv::Mat
+        ovxResult = vxCreateImage(context, width, height, VX_DF_IMAGE_U8);
+        if (vxGetStatus((vx_reference)ovxResult) != VX_SUCCESS)
+            throw std::runtime_error("Failed to create image");
+    }
+    else
+    {
+        //create vx_image based on user data, no copying required
+        output = cv::Mat(height, width, CV_8U, cv::Scalar(0));
+        ovxResult = convertCvMatToVxImage(context, output, false);
+    }
+
+    vx_graph graph;
+    status = createProcessingGraph(ovxImage, ovxResult, graph);
+    if (status != VX_SUCCESS) return status;
+
+    // Graph execution
+    status = vxProcessGraph(graph);
+    if (status != VX_SUCCESS) return status;
+
+    //getting resulting image in cv::Mat
+    if (mode == COPY)
+    {
+        output = copyVxImageToCvMat(ovxResult);
+    }
+    else
+    {
+        //we should take user memory back from vx_image before using it (even before reading)
+        swapVxImage(ovxResult);
+    }
+
+    //here output goes
+    cv::imshow("processing result", output);
+    cv::waitKey(0);
+
+    //we need to take user memory back before releasing the image
+    if (mode == MAP_TO_VX)
+        swapVxImage(ovxImage);
+
+    cv::destroyAllWindows();
+
+    status = vxReleaseContext(&context);
+    return status;
+}
+
+
+int main(int argc, char *argv[])
+{
+    const std::string keys =
+        "{help h usage ? | | }"
+        "{image    | <none> | image to be processed}"
+        "{mode | copy | user memory interaction mode: \n"
+        "copy: create VX images and copy data to/from them\n"
+        "map_to_vx: use handles to user-allocated memory}"
+        ;
+
+    cv::CommandLineParser parser(argc, argv, keys);
+    parser.about("OpenVX interoperability sample demonstrating standard OpenVX API."
+                 "The application loads an image, processes it with OpenVX graph and outputs result in a window");
+    if (parser.has("help"))
+    {
+        parser.printMessage();
+        return 0;
+    }
+    std::string imgPath = parser.get<std::string>("image");
+    std::string modeString = parser.get<std::string>("mode");
+    UserMemoryMode mode;
+    if(modeString == "copy")
+    {
+        mode = COPY;
+    }
+    else if(modeString == "map_to_vx")
+    {
+        mode = MAP_TO_VX;
+    }
+    else if(modeString == "map_from_vx")
+    {
+        std::cerr << modeString << " is not implemented in this sample" << std::endl;
+        return -1;
+    }
+    else
+    {
+        std::cerr << modeString << ": unknown memory mode" << std::endl;
+        return -1;
+    }
+
+    if (!parser.check())
+    {
+        parser.printErrors();
+        return -1;
+    }
+
+    return ovxDemo(imgPath, mode);
+}

samples/openvx/wrappers.cpp

+#include <iostream>
+#include <stdexcept>
+
+//wrappers
+#include "ivx.hpp"
+
+//OpenCV includes
+#include "opencv2/core.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/imgcodecs.hpp"
+#include "opencv2/highgui.hpp"
+
+enum UserMemoryMode
+{
+    COPY, MAP_TO_VX, MAP_FROM_VX
+};
+
+ivx::Graph createProcessingGraph(ivx::Image& inputImage, ivx::Image& outputImage)
+{
+    using namespace ivx;
+
+    Context context = inputImage.getContext();
+
+    Graph graph = Graph::create(context);
+
+    vx_uint32 width  = inputImage.width();
+    vx_uint32 height = inputImage.height();
+
+    // Intermediate images
+    Image
+        smoothed  = Image::createVirtual(graph),
+        cannied   = Image::createVirtual(graph),
+        halfImg   = Image::create(context, width, height, VX_DF_IMAGE_U8),
+        halfCanny = Image::create(context, width, height, VX_DF_IMAGE_U8);
+
+    // Constants
+    vx_uint32 threshCannyMin = 127;
+    vx_uint32 threshCannyMax = 192;
+    Threshold threshCanny = Threshold::createRange(context, VX_TYPE_UINT8, threshCannyMin, threshCannyMax);
+
+    ivx::Scalar alpha = ivx::Scalar::create<VX_TYPE_FLOAT32>(context, 0.5);
+
+    // Sequence of some image operations
+    // Node can also be added in function-like style
+    nodes::gaussian3x3(graph, inputImage, smoothed);
+    Node::create(graph, VX_KERNEL_CANNY_EDGE_DETECTOR, smoothed, threshCanny,
+                 ivx::Scalar::create<VX_TYPE_INT32>(context, 3),
+                 ivx::Scalar::create<VX_TYPE_ENUM>(context, VX_NORM_L2), cannied);
+    Node::create(graph, VX_KERNEL_ACCUMULATE_WEIGHTED, inputImage, alpha, halfImg);
+    Node::create(graph, VX_KERNEL_ACCUMULATE_WEIGHTED, cannied, alpha, halfCanny);
+    Node::create(graph, VX_KERNEL_ADD, halfImg, halfCanny,
+                 ivx::Scalar::create<VX_TYPE_ENUM>(context, VX_CONVERT_POLICY_SATURATE), outputImage);
+
+    graph.verify();
+
+    return graph;
+}
+
+
+int ovxDemo(std::string inputPath, UserMemoryMode mode)
+{
+    using namespace cv;
+    using namespace ivx;
+
+    Mat image = imread(inputPath, IMREAD_GRAYSCALE);
+    if (image.empty()) return -1;
+
+    //check image format
+    if (image.depth() != CV_8U || image.channels() != 1) return -1;
+
+    try
+    {
+        Context context = Context::create();
+        //put user data from cv::Mat to vx_image
+        vx_df_image color = Image::matTypeToFormat(image.type());
+        vx_uint32 width = image.cols, height = image.rows;
+        Image ivxImage;
+        if (mode == COPY)
+        {
+            ivxImage = Image::create(context, width, height, color);
+            ivxImage.copyFrom(0, image);
+        }
+        else
+        {
+            vx_imagepatch_addressing_t addressing = Image::createAddressing(image);
+            const std::vector<vx_imagepatch_addressing_t> addrs(1, addressing);
+            const std::vector<void*> ptrs(1, image.data);
+            ivxImage = Image::createFromHandle(context, color, addrs, ptrs);
+        }
+
+        Image ivxResult;
+        Image::Patch resultPatch;
+        Mat output;
+        if (mode == COPY || mode == MAP_FROM_VX)
+        {
+            //we will copy or map data from vx_image to cv::Mat
+            ivxResult = ivx::Image::create(context, width, height, VX_DF_IMAGE_U8);
+        }
+        else // if (mode == MAP_TO_VX)
+        {
+            //create vx_image based on user data, no copying required
+            output = cv::Mat(height, width, CV_8U, cv::Scalar(0));
+            vx_imagepatch_addressing_t addressing = Image::createAddressing(output);
+            const std::vector<vx_imagepatch_addressing_t> addrs(1, addressing);
+            const std::vector<void*> ptrs(1, output.data);
+            ivxResult = Image::createFromHandle(context, Image::matTypeToFormat(CV_8U), addrs, ptrs);
+        }
+
+        Graph graph = createProcessingGraph(ivxImage, ivxResult);
+
+        // Graph execution
+        graph.process();
+
+        //getting resulting image in cv::Mat
+        if (mode == COPY)
+        {
+            ivxResult.copyTo(0, output);
+        }
+        else if (mode == MAP_FROM_VX)
+        {
+            //create cv::Mat based on vx_image mapped data
+            resultPatch.map(ivxResult, 0, ivxResult.getValidRegion());
+            //generally this is very bad idea!
+            //but in our case unmap() won't happen until output is in use
+            output = resultPatch.getMat();
+        }
+        else // if (mode == MAP_TO_VX)
+        {
+#ifdef VX_VERSION_1_1
+            //we should take user memory back from vx_image before using it (even before reading)
+            ivxResult.swapHandle();
+#endif
+        }
+
+        //here output goes
+        cv::imshow("processing result", output);
+        cv::waitKey(0);
+
+        cv::destroyAllWindows();
+
+#ifdef VX_VERSION_1_1
+        if (mode != COPY)
+        {
+            //we should take user memory back before release
+            //(it's not done automatically according to standard)
+            ivxImage.swapHandle();
+            if (mode == MAP_TO_VX) ivxResult.swapHandle();
+        }
+#endif
+
+        //the line is unnecessary since unmapping is done on destruction of patch
+        //resultPatch.unmap();
+    }
+    catch (const ivx::RuntimeError& e)
+    {
+        std::cerr << "Error: code = " << e.status() << ", message = " << e.what() << std::endl;
+        return e.status();
+    }
+    catch (const ivx::WrapperError& e)
+    {
+        std::cerr << "Error: message = " << e.what() << std::endl;
+        return -1;
+    }
+
+    return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+    const std::string keys =
+        "{help h usage ? | | }"
+        "{image    | <none> | image to be processed}"
+        "{mode | copy | user memory interaction mode: \n"
+        "copy: create VX images and copy data to/from them\n"
+        "map_to_vx: use handles to user-allocated memory\n"
+        "map_from_vx: map resulting VX image to user memory}"
+        ;
+
+    cv::CommandLineParser parser(argc, argv, keys);
+    parser.about("OpenVX interoperability sample demonstrating OpenVX wrappers usage."
+                 "The application loads an image, processes it with OpenVX graph and outputs result in a window");
+    if (parser.has("help"))
+    {
+        parser.printMessage();
+        return 0;
+    }
+    std::string imgPath = parser.get<std::string>("image");
+    std::string modeString = parser.get<std::string>("mode");
+    UserMemoryMode mode;
+    if(modeString == "copy")
+    {
+        mode = COPY;
+    }
+    else if(modeString == "map_to_vx")
+    {
+        mode = MAP_TO_VX;
+    }
+    else if(modeString == "map_from_vx")
+    {
+        mode = MAP_FROM_VX;
+    }
+    else
+    {
+        std::cerr << modeString << ": unknown memory mode" << std::endl;
+        return -1;
+    }
+
+    if (!parser.check())
+    {
+        parser.printErrors();
+        return -1;
+    }
+
+    return ovxDemo(imgPath, mode);
+}

samples/openvx/wrappers_video.cpp

+#include <iostream>
+#include <stdexcept>
+
+//wrappers
+#include "ivx.hpp"
+
+//OpenCV includes
+#include "opencv2/core.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/imgcodecs.hpp"
+#include "opencv2/highgui.hpp"
+
+enum UserMemoryMode
+{
+    COPY, MAP_TO_VX, MAP_FROM_VX
+};
+
+ivx::Graph createProcessingGraph(ivx::Image& inputImage, ivx::Image& outputImage)
+{
+    using namespace ivx;
+
+    Context context = inputImage.getContext();
+
+    Graph graph = Graph::create(context);
+
+    vx_uint32 width  = inputImage.width();
+    vx_uint32 height = inputImage.height();
+
+    // Intermediate images
+    Image
+        yuv       = Image::createVirtual(graph, 0, 0, VX_DF_IMAGE_YUV4),
+        gray      = Image::createVirtual(graph),
+        smoothed  = Image::createVirtual(graph),
+        cannied   = Image::createVirtual(graph),
+        halfImg   = Image::create(context, width, height, VX_DF_IMAGE_U8),
+        halfCanny = Image::create(context, width, height, VX_DF_IMAGE_U8);
+
+    // Constants
+    vx_uint32 threshCannyMin = 127;
+    vx_uint32 threshCannyMax = 192;
+    Threshold threshCanny = Threshold::createRange(context, VX_TYPE_UINT8, threshCannyMin, threshCannyMax);
+
+    ivx::Scalar alpha = ivx::Scalar::create<VX_TYPE_FLOAT32>(context, 0.5);
+
+    // Sequence of some image operations
+    Node::create(graph, VX_KERNEL_COLOR_CONVERT, inputImage, yuv);
+    Node::create(graph, VX_KERNEL_CHANNEL_EXTRACT, yuv,
+                 ivx::Scalar::create<VX_TYPE_ENUM>(context, VX_CHANNEL_Y), gray);
+    //node can also be added in function-like style
+    nodes::gaussian3x3(graph, gray, smoothed);
+    Node::create(graph, VX_KERNEL_CANNY_EDGE_DETECTOR, smoothed, threshCanny,
+                 ivx::Scalar::create<VX_TYPE_INT32>(context, 3),
+                 ivx::Scalar::create<VX_TYPE_ENUM>(context, VX_NORM_L2), cannied);
+    Node::create(graph, VX_KERNEL_ACCUMULATE_WEIGHTED, gray, alpha, halfImg);
+    Node::create(graph, VX_KERNEL_ACCUMULATE_WEIGHTED, cannied, alpha, halfCanny);
+    Node::create(graph, VX_KERNEL_ADD, halfImg, halfCanny,
+                 ivx::Scalar::create<VX_TYPE_ENUM>(context, VX_CONVERT_POLICY_SATURATE), outputImage);
+
+    graph.verify();
+
+    return graph;
+}
+
+
+int ovxDemo(std::string inputPath, UserMemoryMode mode)
+{
+    using namespace cv;
+    using namespace ivx;
+
+    Mat frame;
+    VideoCapture vc(inputPath);
+    if (!vc.isOpened())
+        return -1;
+
+    vc >> frame;
+    if (frame.empty()) return -1;
+
+    //check frame format
+    if (frame.type() != CV_8UC3) return -1;
+
+    try
+    {
+        Context context = Context::create();
+        //put user data from cv::Mat to vx_image
+        vx_df_image color = Image::matTypeToFormat(frame.type());
+        vx_uint32 width = frame.cols, height = frame.rows;
+        Image ivxImage;
+        if (mode == COPY)
+        {
+            ivxImage = Image::create(context, width, height, color);
+        }
+        else
+        {
+            vx_imagepatch_addressing_t addressing = Image::createAddressing(frame);
+            const std::vector<vx_imagepatch_addressing_t> addrs(1, addressing);
+            const std::vector<void*> ptrs(1, frame.data);
+            ivxImage = Image::createFromHandle(context, color, addrs, ptrs);
+        }
+
+        Image ivxResult;
+
+        Mat output;
+        if (mode == COPY || mode == MAP_FROM_VX)
+        {
+            //we will copy or map data from vx_image to cv::Mat
+            ivxResult = ivx::Image::create(context, width, height, VX_DF_IMAGE_U8);
+        }
+        else // if (mode == MAP_TO_VX)
+        {
+            //create vx_image based on user data, no copying required
+            output = cv::Mat(height, width, CV_8U, cv::Scalar(0));
+            vx_imagepatch_addressing_t addressing = Image::createAddressing(output);
+            const std::vector<vx_imagepatch_addressing_t> addrs(1, addressing);
+            const std::vector<void*> ptrs(1, output.data);
+            ivxResult = Image::createFromHandle(context, Image::matTypeToFormat(CV_8U), addrs, ptrs);
+        }
+
+        Graph graph = createProcessingGraph(ivxImage, ivxResult);
+
+        std::vector<void*> ptrs;
+
+        bool stop = false;
+        while (!stop)
+        {
+            if (mode == COPY) ivxImage.copyFrom(0, frame);
+
+            // Graph execution
+            graph.process();
+
+            //getting resulting image in cv::Mat
+            Image::Patch resultPatch;
+            std::vector<void*> prevPtrs;
+            if (mode == COPY)
+            {
+                ivxResult.copyTo(0, output);
+            }
+            else if (mode == MAP_FROM_VX)
+            {
+                //create cv::Mat based on vx_image mapped data
+                resultPatch.map(ivxResult, 0, ivxResult.getValidRegion(), VX_READ_AND_WRITE);
+                //generally this is very bad idea!
+                //but in our case unmap() won't happen until output is in use
+                output = resultPatch.getMat();
+            }
+            else // if(mode == MAP_TO_VX)
+            {
+#ifdef VX_VERSION_1_1
+                //we should take user memory back from vx_image before using it (even before reading)
+                ivxResult.swapHandle(ptrs, prevPtrs);
+#endif
+            }
+
+            //here output goes
+            imshow("press q to quit", output);
+            if ((char)waitKey(1) == 'q') stop = true;
+
+#ifdef VX_VERSION_1_1
+            //restore handle
+            if (mode == MAP_TO_VX)
+            {
+                ivxResult.swapHandle(prevPtrs);
+            }
+#endif
+
+            //this line is unnecessary since unmapping is done on destruction of patch
+            //resultPatch.unmap();
+
+            //grab next frame
+            Mat temp = frame;
+            vc >> frame;
+            if (frame.empty()) stop = true;
+            if (mode != COPY && frame.data != temp.data)
+            {
+                //frame was reallocated, pointer to data changed
+                frame.copyTo(temp);
+            }
+        }
+
+        destroyAllWindows();
+
+#ifdef VX_VERSION_1_1
+        if (mode != COPY)
+        {
+            //we should take user memory back before release
+            //(it's not done automatically according to standard)
+            ivxImage.swapHandle();
+            if (mode == MAP_TO_VX) ivxResult.swapHandle();
+        }
+#endif
+    }
+    catch (const ivx::RuntimeError& e)
+    {
+        std::cerr << "Error: code = " << e.status() << ", message = " << e.what() << std::endl;
+        return e.status();
+    }
+    catch (const ivx::WrapperError& e)
+    {
+        std::cerr << "Error: message = " << e.what() << std::endl;
+        return -1;
+    }
+
+    return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+    const std::string keys =
+        "{help h usage ? | | }"
+        "{video    | <none> | video file to be processed}"
+        "{mode | copy | user memory interaction mode: \n"
+        "copy: create VX images and copy data to/from them\n"
+        "map_to_vx: use handles to user-allocated memory\n"
+        "map_from_vx: map resulting VX image to user memory}"
+        ;
+
+    cv::CommandLineParser parser(argc, argv, keys);
+    parser.about("OpenVX interoperability sample demonstrating OpenVX wrappers usage."
+                 "The application opens a video and processes it with OpenVX graph while outputting result in a window");
+    if (parser.has("help"))
+    {
+        parser.printMessage();
+        return 0;
+    }
+    std::string videoPath = parser.get<std::string>("video");
+    std::string modeString = parser.get<std::string>("mode");
+    UserMemoryMode mode;
+    if(modeString == "copy")
+    {
+        mode = COPY;
+    }
+    else if(modeString == "map_to_vx")
+    {
+        mode = MAP_TO_VX;
+    }
+    else if(modeString == "map_from_vx")
+    {
+        mode = MAP_FROM_VX;
+    }
+    else
+    {
+        std::cerr << modeString << ": unknown memory mode" << std::endl;
+        return -1;
+    }
+
+    if (!parser.check())
+    {
+        parser.printErrors();
+        return -1;
+    }
+
+    return ovxDemo(videoPath, mode);
+}