diff --git a/modules/calib3d/include/opencv2/calib3d/calib3d.hpp b/modules/calib3d/include/opencv2/calib3d/calib3d.hpp
index 5e9c2f6657..c45d9ce98a 100644
--- a/modules/calib3d/include/opencv2/calib3d/calib3d.hpp
+++ b/modules/calib3d/include/opencv2/calib3d/calib3d.hpp
@@ -730,7 +730,7 @@ protected:
 
 //! filters off speckles (small regions of incorrectly computed disparity)
 CV_EXPORTS_W void filterSpeckles( InputOutputArray img, double newVal, int maxSpeckleSize, double maxDiff,
-                                  InputOutputArray buf=InputOutputArray() );
+                                  InputOutputArray buf=None() );
 
 //! computes valid disparity ROI from the valid ROIs of the rectified images (that are returned by cv::stereoRectify())
 CV_EXPORTS_W Rect getValidDisparityROI( Rect roi1, Rect roi2,
diff --git a/modules/core/src/persistence.cpp b/modules/core/src/persistence.cpp
index 6558b42f00..f6544e918d 100644
--- a/modules/core/src/persistence.cpp
+++ b/modules/core/src/persistence.cpp
@@ -1424,9 +1424,9 @@ icvYMLWrite( CvFileStorage* fs, const char* key, const char* data )
 
         for( i = 0; i < keylen; i++ )
         {
-            int c = key[i];
+            char c = key[i];
 
-            ptr[i] = (char)c;
+            ptr[i] = c;
             if( !cv_isalnum(c) && c != '-' && c != '_' && c != ' ' )
                 CV_Error( CV_StsBadArg, "Key names may only contain alphanumeric characters [a-zA-Z0-9], '-', '_' and ' '" );
         }
diff --git a/modules/features2d/src/orb.cpp b/modules/features2d/src/orb.cpp
index 2e6793e4a5..05d66ca05e 100644
--- a/modules/features2d/src/orb.cpp
+++ b/modules/features2d/src/orb.cpp
@@ -469,7 +469,7 @@ ORB::ORB(size_t n_features, const CommonParams & detector_params) :
   params_(detector_params), n_features_(n_features)
 {
   // fill the extractors and descriptors for the corresponding scales
-  float factor = 1.0 / params_.scale_factor_ / params_.scale_factor_;
+  float factor = (float)(1.0 / params_.scale_factor_ / params_.scale_factor_);
   int n_desired_features_per_scale = cvRound(n_features / ((std::pow(factor, int(params_.n_levels_)) - 1)
                                                  / (factor - 1)));
   n_features_per_level_.resize(detector_params.n_levels_);
diff --git a/modules/features2d/src/sift.cpp b/modules/features2d/src/sift.cpp
index 0f961d88a4..303f9af976 100644
--- a/modules/features2d/src/sift.cpp
+++ b/modules/features2d/src/sift.cpp
@@ -637,7 +637,7 @@ static struct feature* interp_extremum( IplImage*** dog_pyr, int octv,
 {
   struct feature* feat;
   struct detection_data* ddata;
-  double xi, xr, xc, contr;
+  double xi=0, xr=0, xc=0, contr;
   int i = 0;
 
   while( i < SIFT_MAX_INTERP_STEPS )
diff --git a/modules/imgproc/src/color.cpp b/modules/imgproc/src/color.cpp
index 97e33251d3..b9748c8a08 100644
--- a/modules/imgproc/src/color.cpp
+++ b/modules/imgproc/src/color.cpp
@@ -2653,12 +2653,12 @@ static void Bayer2RGB_VNG_8u( const Mat& srcmat, Mat& dstmat, int code )
 template<int R>
 struct YUV420i2BGR888Invoker
 {
-    Mat& dst;
+    Mat* dst;
     const uchar* my1, *muv;
     int width;
 
     YUV420i2BGR888Invoker(Mat& _dst, int _width, const uchar* _y1, const uchar* _uv)
-        : dst(_dst), my1(_y1), muv(_uv), width(_width) {}
+        : dst(&_dst), my1(_y1), muv(_uv), width(_width) {}
 
     void operator()(const BlockedRange& range) const
     {
@@ -2670,8 +2670,8 @@ struct YUV420i2BGR888Invoker
 
         for (int j = range.begin(); j < range.end(); j+=2, y1+=width*2, uv+=width)
         {
-            uchar* row1 = dst.ptr<uchar>(j);
-            uchar* row2 = dst.ptr<uchar>(j+1);
+            uchar* row1 = dst->ptr<uchar>(j);
+            uchar* row2 = dst->ptr<uchar>(j+1);
             const uchar* y2 = y1 + width;
 
             for(int i = 0; i < width; i+=2,row1+=6,row2+=6)
@@ -2710,12 +2710,12 @@ struct YUV420i2BGR888Invoker
 template<int R>
 struct YUV420i2BGRA8888Invoker
 {
-    Mat& dst;
+    Mat* dst;
     const uchar* my1, *muv;
     int width;
 
     YUV420i2BGRA8888Invoker(Mat& _dst, int _width, const uchar* _y1, const uchar* _uv)
-        : dst(_dst), my1(_y1), muv(_uv), width(_width) {}
+        : dst(&_dst), my1(_y1), muv(_uv), width(_width) {}
 
     void operator()(const BlockedRange& range) const
     {
@@ -2727,8 +2727,8 @@ struct YUV420i2BGRA8888Invoker
 
         for (int j = range.begin(); j < range.end(); j+=2, y1+=width*2, uv+=width)
         {
-            uchar* row1 = dst.ptr<uchar>(j);
-            uchar* row2 = dst.ptr<uchar>(j+1);
+            uchar* row1 = dst->ptr<uchar>(j);
+            uchar* row2 = dst->ptr<uchar>(j+1);
             const uchar* y2 = y1 + width;
 
             for(int i = 0; i < width; i+=2,row1+=8,row2+=8)
diff --git a/modules/video/src/bgfg_gaussmix2.cpp b/modules/video/src/bgfg_gaussmix2.cpp
index dbb1395845..9fcad2320b 100644
--- a/modules/video/src/bgfg_gaussmix2.cpp
+++ b/modules/video/src/bgfg_gaussmix2.cpp
@@ -1320,7 +1320,7 @@ void BackgroundSubtractorMOG2::getBackgroundImage(OutputArray backgroundImage) c
                     break;
             }
 
-            Vec3f val = Vec3f(meanVal[0], meanVal[1], meanVal[2]) * (1.0 / totalWeight);
+            Vec3f val = Vec3f((float)meanVal[0], (float)meanVal[1], (float)meanVal[2]) * (float)(1.0 / totalWeight);
             meanBackground.at<Vec3b>(row, col) = Vec3b(val);
             firstGaussianIdx += nmixtures;
         }
@@ -1343,7 +1343,7 @@ void BackgroundSubtractorMOG2::getBackgroundImage(OutputArray backgroundImage) c
         }
 
         default:
-            CV_Assert(false);
+            CV_Error(CV_StsUnsupportedFormat, "");
     }
 }
 
diff --git a/samples/cpp/video_homography.cpp b/samples/cpp/video_homography.cpp
index 1f9c020202..cee6b9b01e 100644
--- a/samples/cpp/video_homography.cpp
+++ b/samples/cpp/video_homography.cpp
@@ -160,7 +160,7 @@ int main(int ac, char ** av)
     {
         capture >> frame;
         if (frame.empty())
-            continue;
+            break;
 
         cvtColor(frame, gray, CV_RGB2GRAY);