core(libva): use dynamic loader

modules/core/src/va_intel.cpp

@@ -33,6 +33,17 @@ using namespace cv;
 #endif
 #endif
 
+#ifdef HAVE_VA
+#ifndef OPENCV_LIBVA_LINK
+#include "va_wrapper.impl.hpp"
+#else
+namespace cv { namespace detail {
+static void init_libva() { /* nothing */ }
+}}  // namespace
+#endif
+using namespace cv::detail;
+#endif
+
 namespace cv { namespace va_intel {
 
 #ifdef HAVE_VA_INTEL
@@ -54,6 +65,8 @@ Context& initializeContextFromVA(VADisplay display, bool tryInterop)
 #if !defined(HAVE_VA)
     NO_VA_SUPPORT_ERROR;
 #else  // !HAVE_VA
+    init_libva();
+
 #   ifdef HAVE_VA_INTEL
     contextInitialized = false;
     if (tryInterop)
@@ -507,6 +520,8 @@ void convertToVASurface(VADisplay display, InputArray src, VASurfaceID surface,
 #if !defined(HAVE_VA)
     NO_VA_SUPPORT_ERROR;
 #else  // !HAVE_VA
+    init_libva();
+
     const int stype = CV_8UC3;
 
     int srcType = src.type();
@@ -611,6 +626,8 @@ void convertFromVASurface(VADisplay display, VASurfaceID surface, Size size, Out
 #if !defined(HAVE_VA)
     NO_VA_SUPPORT_ERROR;
 #else  // !HAVE_VA
+    init_libva();
+
     const int dtype = CV_8UC3;
 
     // TODO Need to specify ACCESS_WRITE here somehow to prevent useless data copying!

modules/core/src/va_wrapper.impl.hpp

@@ -0,0 +1,85 @@
+// 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.
+
+//
+// Not a standalone header, part of va_intel.cpp
+//
+
+#include "opencv2/core/utils/plugin_loader.private.hpp"  // DynamicLib
+
+namespace cv { namespace detail {
+
+typedef VAStatus (*FN_vaDeriveImage)(VADisplay dpy, VASurfaceID surface, VAImage *image);
+typedef VAStatus (*FN_vaDestroyImage)(VADisplay dpy, VAImageID image);
+typedef VAStatus (*FN_vaMapBuffer)(VADisplay dpy, VABufferID buf_id, void **pbuf);
+typedef VAStatus (*FN_vaSyncSurface)(VADisplay dpy, VASurfaceID render_target);
+typedef VAStatus (*FN_vaUnmapBuffer)(VADisplay dpy, VABufferID buf_id);
+
+static FN_vaDeriveImage fn_vaDeriveImage = NULL;
+static FN_vaDestroyImage fn_vaDestroyImage = NULL;
+static FN_vaMapBuffer fn_vaMapBuffer = NULL;
+static FN_vaSyncSurface fn_vaSyncSurface = NULL;
+static FN_vaUnmapBuffer fn_vaUnmapBuffer = NULL;
+
+#define vaDeriveImage fn_vaDeriveImage
+#define vaDestroyImage fn_vaDestroyImage
+#define vaMapBuffer fn_vaMapBuffer
+#define vaSyncSurface fn_vaSyncSurface
+#define vaUnmapBuffer fn_vaUnmapBuffer
+
+
+static std::shared_ptr<cv::plugin::impl::DynamicLib> loadLibVA()
+{
+    std::shared_ptr<cv::plugin::impl::DynamicLib> lib;
+    const char* envPath = getenv("OPENCV_LIBVA_RUNTIME");
+    if (envPath)
+    {
+        lib = std::make_shared<cv::plugin::impl::DynamicLib>(envPath);
+        return lib;
+    }
+    static const char* const candidates[] = {
+        "libva.so",
+        "libva.so.2",
+        "libva.so.1",
+    };
+    for (int i = 0; i < 3; ++i)
+    {
+        lib = std::make_shared<cv::plugin::impl::DynamicLib>(candidates[i]);
+        if (lib->isLoaded())
+            break;
+    }
+    return lib;
+}
+static void init_libva()
+{
+    static bool initialized = false;
+    static auto library = loadLibVA();
+    if (!initialized)
+    {
+        if (!library || !library->isLoaded())
+        {
+            library.reset();
+            CV_Error(cv::Error::StsBadFunc, "OpenCV can't load VA library (libva)");
+        }
+        auto& lib = *library.get();
+#define VA_LOAD_SYMBOL(name) fn_ ## name = reinterpret_cast<FN_ ## name>(lib.getSymbol(#name)); \
+        if (!fn_ ## name) \
+        { \
+            library.reset(); \
+            initialized = true; \
+            CV_Error_(cv::Error::StsBadFunc, ("OpenCV can't load VA library (libva), missing symbol: %s", #name)); \
+        }
+
+        VA_LOAD_SYMBOL(vaDeriveImage);
+        VA_LOAD_SYMBOL(vaDestroyImage);
+        VA_LOAD_SYMBOL(vaMapBuffer);
+        VA_LOAD_SYMBOL(vaSyncSurface);
+        VA_LOAD_SYMBOL(vaUnmapBuffer);
+        initialized = true;
+    }
+    if (!library)
+        CV_Error(cv::Error::StsBadFunc, "OpenCV can't load/initialize VA library (libva)");
+}
+
+}}  // namespace