Merge pull request #20546 from sivanov-work:initial_vpl_source

G-API: oneVPL (simplification) source base commit

* oneVPL source initial

* Fix compilation

* Fix compilation path

* Fix NO VPL compile

* Fix unused vars

* Fix unused vars in example

* Simplify oneVPL search: no custom path & download

* Fix standalone GAPI

* Apply comments

modules/gapi/src/streaming/onevpl/onevpl_source.cpp

@@ -0,0 +1,48 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2021 Intel Corporation
+
+#include <opencv2/gapi/streaming/onevpl/onevpl_source.hpp>
+
+#include "streaming/onevpl/onevpl_source_priv.hpp"
+
+namespace cv {
+namespace gapi {
+namespace wip {
+
+#ifdef HAVE_ONEVPL
+OneVPLSource::OneVPLSource(const std::string& filePath) :
+    OneVPLSource(std::unique_ptr<Priv>(new OneVPLSource::Priv(filePath))) {
+
+    if (filePath.empty()) {
+        util::throw_error(std::logic_error("Cannot create 'OneVPLSource' on empty source file name"));
+    }
+}
+#else
+OneVPLSource::OneVPLSource(const std::string&) {
+    GAPI_Assert(false && "Unsupported: G-API compiled without `WITH_GAPI_ONEVPL=ON`");
+}
+#endif
+
+OneVPLSource::OneVPLSource(std::unique_ptr<Priv>&& impl) :
+    IStreamSource(),
+    m_priv(std::move(impl)) {
+}
+
+OneVPLSource::~OneVPLSource() {
+}
+
+bool OneVPLSource::pull(cv::gapi::wip::Data& data)
+{
+    return m_priv->pull(data);
+}
+
+GMetaArg OneVPLSource::descr_of() const
+{
+    return m_priv->descr_of();
+}
+} // namespace wip
+} // namespace gapi
+} // namespace cv

modules/gapi/src/streaming/onevpl/onevpl_source_priv.cpp

@@ -0,0 +1,63 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2021 Intel Corporation
+
+#include <algorithm>
+#include <sstream>
+
+#include "streaming/onevpl/onevpl_source_priv.hpp"
+#include "logger.hpp"
+
+#ifndef HAVE_ONEVPL
+namespace cv {
+namespace gapi {
+namespace wip {
+bool OneVPLSource::Priv::pull(cv::gapi::wip::Data&) {
+    return true;
+}
+GMetaArg OneVPLSource::Priv::descr_of() const {
+    return {};
+}
+} // namespace wip
+} // namespace gapi
+} // namespace cv
+
+#else // HAVE_ONEVPL
+
+namespace cv {
+namespace gapi {
+namespace wip {
+OneVPLSource::Priv::Priv() :
+    mfx_handle(MFXLoad())
+{
+    GAPI_LOG_INFO(nullptr, "Initialized MFX handle: " << mfx_handle);
+    description_is_valid = false;
+}
+
+OneVPLSource::Priv::Priv(const std::string&) :
+    OneVPLSource::Priv()
+{
+}
+
+OneVPLSource::Priv::~Priv()
+{
+    GAPI_LOG_INFO(nullptr, "Unload MFX handle: " << mfx_handle);
+    MFXUnload(mfx_handle);
+}
+
+bool OneVPLSource::Priv::pull(cv::gapi::wip::Data&)
+{
+    return false;
+}
+
+GMetaArg OneVPLSource::Priv::descr_of() const
+{
+    return {};
+}
+} // namespace wip
+} // namespace gapi
+} // namespace cv
+
+#endif // HAVE_ONEVPL

modules/gapi/src/streaming/onevpl/onevpl_source_priv.hpp

@@ -0,0 +1,62 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2021 Intel Corporation
+
+#ifndef OPENCV_GAPI_STREAMING_ONEVPL_ONEVPL_SOURCE_PRIV_HPP
+#define OPENCV_GAPI_STREAMING_ONEVPL_ONEVPL_SOURCE_PRIV_HPP
+
+#include <stdio.h>
+
+#include <memory>
+#include <string>
+
+#include <opencv2/gapi/garg.hpp>
+#include <opencv2/gapi/streaming/meta.hpp>
+#include <opencv2/gapi/streaming/onevpl/onevpl_source.hpp>
+
+#ifdef HAVE_ONEVPL
+#if (MFX_VERSION >= 2000)
+#include <vpl/mfxdispatcher.h>
+#endif // MFX_VERSION
+
+#include <vpl/mfx.h>
+
+#include <vpl/mfxvideo.h>
+
+namespace cv {
+namespace gapi {
+namespace wip {
+
+struct OneVPLSource::Priv
+{
+    explicit Priv(const std::string& file_path);
+    ~Priv();
+
+    bool pull(cv::gapi::wip::Data& data);
+    GMetaArg descr_of() const;
+private:
+    Priv();
+    mfxLoader mfx_handle;
+    bool description_is_valid;
+};
+} // namespace wip
+} // namespace gapi
+} // namespace cv
+
+#else // HAVE_ONEVPL
+
+namespace cv {
+namespace gapi {
+namespace wip {
+struct OneVPLSource::Priv final
+{
+    bool pull(cv::gapi::wip::Data&);
+    GMetaArg descr_of() const;
+};
+} // namespace wip
+} // namespace gapi
+} // namespace cv
+#endif // HAVE_ONEVPL
+#endif // OPENCV_GAPI_STREAMING_ONEVPL_ONEVPL_SOURCE_PRIV_HPP