videoio: decreased log level for failed backends in VideoCapture and VideoWriter open

modules/videoio/src/cap.cpp

@@ -161,7 +161,7 @@ bool VideoCapture::open(const String& filename, int apiPreference, const std::ve
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised OpenCV exception:\n\n%s\n",
                                               info.name, e.what()));
                 }
@@ -171,7 +171,7 @@ bool VideoCapture::open(const String& filename, int apiPreference, const std::ve
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
+                    CV_LOG_WARNING(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
                                                     info.name, e.what()));
                 }
                 catch (...)
@@ -180,7 +180,7 @@ bool VideoCapture::open(const String& filename, int apiPreference, const std::ve
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised unknown C++ exception!\n\n",
                                               info.name));
                 }
@@ -299,7 +299,7 @@ bool VideoCapture::open(int cameraNum, int apiPreference, const std::vector<int>
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised OpenCV exception:\n\n%s\n",
                                               info.name, e.what()));
                 }
@@ -309,7 +309,7 @@ bool VideoCapture::open(int cameraNum, int apiPreference, const std::vector<int>
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
+                    CV_LOG_WARNING(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
                                                     info.name, e.what()));
                 }
                 catch (...)
@@ -318,7 +318,7 @@ bool VideoCapture::open(int cameraNum, int apiPreference, const std::vector<int>
                     {
                         throw;
                     }
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised unknown C++ exception!\n\n",
                                               info.name));
                 }
@@ -640,18 +640,18 @@ bool VideoWriter::open(const String& filename, int apiPreference, int fourcc, do
                 }
                 catch (const cv::Exception& e)
                 {
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised OpenCV exception:\n\n%s\n",
                                               info.name, e.what()));
                 }
                 catch (const std::exception& e)
                 {
-                    CV_LOG_ERROR(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
+                    CV_LOG_WARNING(NULL, cv::format("VIDEOIO(%s): raised C++ exception:\n\n%s\n",
                                                     info.name, e.what()));
                 }
                 catch (...)
                 {
-                    CV_LOG_ERROR(NULL,
+                    CV_LOG_WARNING(NULL,
                                    cv::format("VIDEOIO(%s): raised unknown C++ exception!\n\n",
                                               info.name));
                 }