diff --git a/apps/createsamples/utility.cpp b/apps/createsamples/utility.cpp
index cf2bdebbf9..2226cd8c92 100644
--- a/apps/createsamples/utility.cpp
+++ b/apps/createsamples/utility.cpp
@@ -1270,7 +1270,7 @@ void cvCreateTrainingSamples( const char* filename,
                 if( showsamples )
                 {
                     cvShowImage( "Sample", &sample );
-                    if( cvWaitKey( 0 ) == 27 )
+                    if( (cvWaitKey( 0 ) & 0xFF) == 27 )
                     {
                         showsamples = 0;
                     }
@@ -1402,7 +1402,7 @@ void cvCreateTestSamples( const char* infoname,
                 if( showsamples )
                 {
                     cvShowImage( "Image", &cvbgreader->src );
-                    if( cvWaitKey( 0 ) == 27 )
+                    if( (cvWaitKey( 0 ) & 0xFF) == 27 )
                     {
                         showsamples = 0;
                     }
@@ -1525,7 +1525,7 @@ int cvCreateTrainingSamplesFromInfo( const char* infoname, const char* vecfilena
             if( showsamples )
             {
                 cvShowImage( "Sample", sample );
-                if( cvWaitKey( 0 ) == 27 )
+                if( (cvWaitKey( 0 ) & 0xFF) == 27 )
                 {
                     showsamples = 0;
                 }
@@ -1672,7 +1672,7 @@ void cvShowVecSamples( const char* filename, int winwidth, int winheight,
                 icvGetTraininDataFromVec( sample, &file );
                 if( scale != 1.0 ) cvResize( sample, scaled_sample, CV_INTER_LINEAR);
                 cvShowImage( "Sample", scaled_sample );
-                if( cvWaitKey( 0 ) == 27 ) break;
+                if( (cvWaitKey( 0 ) & 0xFF) == 27 ) break;
             }
             if( scaled_sample && scaled_sample != sample ) cvReleaseMat( &scaled_sample );
             cvReleaseMat( &sample );
@@ -1680,4 +1680,4 @@ void cvShowVecSamples( const char* filename, int winwidth, int winheight,
         }
         fclose( file.input );
     }
-}
\ No newline at end of file
+}
diff --git a/apps/interactive-calibration/calibPipeline.cpp b/apps/interactive-calibration/calibPipeline.cpp
index 1047bfce5f..a92dbffc2f 100644
--- a/apps/interactive-calibration/calibPipeline.cpp
+++ b/apps/interactive-calibration/calibPipeline.cpp
@@ -68,7 +68,7 @@ PipelineExitStatus CalibPipeline::start(std::vector<cv::Ptr<FrameProcessor> > pr
         for (std::vector<cv::Ptr<FrameProcessor> >::iterator it = processors.begin(); it != processors.end(); ++it)
             processedFrame = (*it)->processFrame(processedFrame);
         cv::imshow(mainWindowName, processedFrame);
-        int key = cv::waitKey(CAP_DELAY);
+        char key = (char)cv::waitKey(CAP_DELAY);
 
         if(key == 27) // esc
             return Finished;
diff --git a/doc/tutorials/imgproc/imgtrans/remap/remap.markdown b/doc/tutorials/imgproc/imgtrans/remap/remap.markdown
index 849157f077..34a0b90201 100644
--- a/doc/tutorials/imgproc/imgtrans/remap/remap.markdown
+++ b/doc/tutorials/imgproc/imgtrans/remap/remap.markdown
@@ -85,9 +85,9 @@ Explanation
     while( true )
     {
       /// Each 1 sec. Press ESC to exit the program
-      int c = waitKey( 1000 );
+      char c = (char)waitKey( 1000 );
 
-      if( (char)c == 27 )
+      if( c == 27 )
         { break; }
 
       /// Update map_x & map_y. Then apply remap
diff --git a/doc/tutorials/imgproc/pyramids/pyramids.markdown b/doc/tutorials/imgproc/pyramids/pyramids.markdown
index 69df1cda63..5210ec007d 100644
--- a/doc/tutorials/imgproc/pyramids/pyramids.markdown
+++ b/doc/tutorials/imgproc/pyramids/pyramids.markdown
@@ -93,6 +93,7 @@ Let's check the general structure of the program:
 
 -   Perform an infinite loop waiting for user input.
     @snippet cpp/tutorial_code/ImgProc/Pyramids.cpp infinite_loop
+
     Our program exits if the user presses *ESC*. Besides, it has two options:
 
     -   **Perform upsampling (after pressing 'u')**
diff --git a/modules/python/test/tst_scene_render.py b/modules/python/test/tst_scene_render.py
index 49cde80d25..25d5a4058e 100644
--- a/modules/python/test/tst_scene_render.py
+++ b/modules/python/test/tst_scene_render.py
@@ -113,7 +113,7 @@ if __name__ == '__main__':
         img = render.getNextFrame()
         cv2.imshow('img', img)
 
-        ch = 0xFF & cv2.waitKey(3)
-        if  ch == 27:
+        ch = cv2.waitKey(3)
+        if ch == 27:
             break
-    cv2.destroyAllWindows()
\ No newline at end of file
+    cv2.destroyAllWindows()
diff --git a/samples/cpp/3calibration.cpp b/samples/cpp/3calibration.cpp
index 7079b6d062..8affef17ff 100644
--- a/samples/cpp/3calibration.cpp
+++ b/samples/cpp/3calibration.cpp
@@ -351,7 +351,7 @@ int main( int argc, char** argv )
         for( k = 0; k < small_canvas.rows; k += 16 )
             line(small_canvas, Point(0, k), Point(small_canvas.cols, k), Scalar(0,255,0), 1);
         imshow("rectified", small_canvas);
-        int c = waitKey(0);
+        char c = (char)waitKey(0);
         if( c == 27 || c == 'q' || c == 'Q' )
             break;
     }
diff --git a/samples/cpp/calibration.cpp b/samples/cpp/calibration.cpp
index 415d8bb837..251ab83e72 100644
--- a/samples/cpp/calibration.cpp
+++ b/samples/cpp/calibration.cpp
@@ -493,9 +493,9 @@ int main( int argc, char** argv )
         }
 
         imshow("Image View", view);
-        int key = 0xff & waitKey(capture.isOpened() ? 50 : 500);
+        char key = (char)waitKey(capture.isOpened() ? 50 : 500);
 
-        if( (key & 255) == 27 )
+        if( key == 27 )
             break;
 
         if( key == 'u' && mode == CALIBRATED )
@@ -536,8 +536,8 @@ int main( int argc, char** argv )
             //undistort( view, rview, cameraMatrix, distCoeffs, cameraMatrix );
             remap(view, rview, map1, map2, INTER_LINEAR);
             imshow("Image View", rview);
-            int c = 0xff & waitKey();
-            if( (c & 255) == 27 || c == 'q' || c == 'Q' )
+            char c = (char)waitKey();
+            if( c == 27 || c == 'q' || c == 'Q' )
                 break;
         }
     }
diff --git a/samples/cpp/cloning_gui.cpp b/samples/cpp/cloning_gui.cpp
index 289eae8de0..4358abc33f 100644
--- a/samples/cpp/cloning_gui.cpp
+++ b/samples/cpp/cloning_gui.cpp
@@ -453,7 +453,7 @@ int main()
 
     for(;;)
     {
-        char key = (char) waitKey(0);
+        char key = (char)waitKey(0);
 
         if(key == 'd' && flag3 == 0)
         {
diff --git a/samples/cpp/convexhull.cpp b/samples/cpp/convexhull.cpp
index fd2275645d..f89e5b27bb 100644
--- a/samples/cpp/convexhull.cpp
+++ b/samples/cpp/convexhull.cpp
@@ -25,7 +25,6 @@ int main( int argc, char** argv )
 
     for(;;)
     {
-        char key;
         int i, count = (unsigned)rng%100 + 1;
 
         vector<Point> points;
@@ -58,7 +57,7 @@ int main( int argc, char** argv )
 
         imshow("hull", img);
 
-        key = (char)waitKey();
+        char key = (char)waitKey();
         if( key == 27 || key == 'q' || key == 'Q' ) // 'ESC'
             break;
     }
diff --git a/samples/cpp/detect_mser.cpp b/samples/cpp/detect_mser.cpp
index ce29db3d3b..04429ccc56 100644
--- a/samples/cpp/detect_mser.cpp
+++ b/samples/cpp/detect_mser.cpp
@@ -279,8 +279,8 @@ static void DrawOpenGLMSER(Mat img, Mat result)
     for (;;)
         {
         updateWindow("OpenGL");
-        int key = waitKey(40);
-        if ((key & 0xff) == 27)
+        char key = (char)waitKey(40);
+        if (key == 27)
             break;
         if (key == 0x20)
             rotateEnable = !rotateEnable;
diff --git a/samples/cpp/distrans.cpp b/samples/cpp/distrans.cpp
index 4bf4707ba6..21432642ec 100644
--- a/samples/cpp/distrans.cpp
+++ b/samples/cpp/distrans.cpp
@@ -133,7 +133,7 @@ int main( int argc, const char** argv )
         // Call to update the view
         onTrackbar(0, 0);
 
-        int c = waitKey(0) & 255;
+        char c = (char)waitKey(0);
 
         if( c == 27 )
             break;
diff --git a/samples/cpp/facedetect.cpp b/samples/cpp/facedetect.cpp
index 8f6a45666f..86d3284fc2 100644
--- a/samples/cpp/facedetect.cpp
+++ b/samples/cpp/facedetect.cpp
@@ -72,9 +72,9 @@ int main( int argc, const char** argv )
     }
     if( inputName.empty() || (isdigit(inputName[0]) && inputName.size() == 1) )
     {
-        int c = inputName.empty() ? 0 : inputName[0] - '0';
-        if(!capture.open(c))
-            cout << "Capture from camera #" <<  c << " didn't work" << endl;
+        int camera = inputName.empty() ? 0 : inputName[0] - '0';
+        if(!capture.open(camera))
+            cout << "Capture from camera #" <<  camera << " didn't work" << endl;
     }
     else if( inputName.size() )
     {
@@ -104,7 +104,7 @@ int main( int argc, const char** argv )
             Mat frame1 = frame.clone();
             detectAndDraw( frame1, cascade, nestedCascade, scale, tryflip );
 
-            int c = waitKey(10);
+            char c = (char)waitKey(10);
             if( c == 27 || c == 'q' || c == 'Q' )
                 break;
         }
@@ -127,7 +127,7 @@ int main( int argc, const char** argv )
                 char buf[1000+1];
                 while( fgets( buf, 1000, f ) )
                 {
-                    int len = (int)strlen(buf), c;
+                    int len = (int)strlen(buf);
                     while( len > 0 && isspace(buf[len-1]) )
                         len--;
                     buf[len] = '\0';
@@ -136,7 +136,7 @@ int main( int argc, const char** argv )
                     if( !image.empty() )
                     {
                         detectAndDraw( image, cascade, nestedCascade, scale, tryflip );
-                        c = waitKey(0);
+                        char c = (char)waitKey(0);
                         if( c == 27 || c == 'q' || c == 'Q' )
                             break;
                     }
diff --git a/samples/cpp/ffilldemo.cpp b/samples/cpp/ffilldemo.cpp
index d10d72e0eb..0cf315568d 100644
--- a/samples/cpp/ffilldemo.cpp
+++ b/samples/cpp/ffilldemo.cpp
@@ -105,13 +105,13 @@ int main( int argc, char** argv )
     {
         imshow("image", isColor ? image : gray);
 
-        int c = waitKey(0);
-        if( (c & 255) == 27 )
+        char c = (char)waitKey(0);
+        if( c == 27 )
         {
             cout << "Exiting ...\n";
             break;
         }
-        switch( (char)c )
+        switch( c )
         {
         case 'c':
             if( isColor )
diff --git a/samples/cpp/grabcut.cpp b/samples/cpp/grabcut.cpp
index 726906c6ff..54edbf61ec 100644
--- a/samples/cpp/grabcut.cpp
+++ b/samples/cpp/grabcut.cpp
@@ -306,8 +306,8 @@ int main( int argc, char** argv )
 
     for(;;)
     {
-        int c = waitKey(0);
-        switch( (char) c )
+        char c = (char)waitKey(0);
+        switch( c )
         {
         case '\x1b':
             cout << "Exiting ..." << endl;
diff --git a/samples/cpp/laplace.cpp b/samples/cpp/laplace.cpp
index 462f62804e..958fccb608 100644
--- a/samples/cpp/laplace.cpp
+++ b/samples/cpp/laplace.cpp
@@ -83,10 +83,10 @@ int main( int argc, char** argv )
         convertScaleAbs(laplace, result, (sigma+1)*0.25);
         imshow("Laplacian", result);
 
-        int c = waitKey(30);
+        char c = (char)waitKey(30);
         if( c == ' ' )
             smoothType = smoothType == GAUSSIAN ? BLUR : smoothType == BLUR ? MEDIAN : GAUSSIAN;
-        if( c == 'q' || c == 'Q' || (c & 255) == 27 )
+        if( c == 'q' || c == 'Q' || c == 27 )
             break;
     }
 
diff --git a/samples/cpp/morphology2.cpp b/samples/cpp/morphology2.cpp
index 8439080b2b..b7dc68f6c0 100644
--- a/samples/cpp/morphology2.cpp
+++ b/samples/cpp/morphology2.cpp
@@ -82,21 +82,19 @@ int main( int argc, char** argv )
 
     for(;;)
     {
-        int c;
-
         OpenClose(open_close_pos, 0);
         ErodeDilate(erode_dilate_pos, 0);
-        c = waitKey(0);
+        char c = (char)waitKey(0);
 
-        if( (char)c == 27 )
+        if( c == 27 )
             break;
-        if( (char)c == 'e' )
+        if( c == 'e' )
             element_shape = MORPH_ELLIPSE;
-        else if( (char)c == 'r' )
+        else if( c == 'r' )
             element_shape = MORPH_RECT;
-        else if( (char)c == 'c' )
+        else if( c == 'c' )
             element_shape = MORPH_CROSS;
-        else if( (char)c == ' ' )
+        else if( c == ' ' )
             element_shape = (element_shape + 1) % 3;
     }
 
diff --git a/samples/cpp/pca.cpp b/samples/cpp/pca.cpp
index b33a463211..fb2f585af8 100644
--- a/samples/cpp/pca.cpp
+++ b/samples/cpp/pca.cpp
@@ -183,9 +183,9 @@ int main(int argc, char** argv)
     // display until user presses q
     imshow(winName, reconstruction);
 
-    int key = 0;
+    char key = 0;
     while(key != 'q')
-        key = waitKey();
+        key = (char)waitKey();
 
    return 0;
 }
diff --git a/samples/cpp/phase_corr.cpp b/samples/cpp/phase_corr.cpp
index c3120fe084..f7356666c4 100644
--- a/samples/cpp/phase_corr.cpp
+++ b/samples/cpp/phase_corr.cpp
@@ -9,7 +9,7 @@ int main(int, char* [])
 {
     VideoCapture video(0);
     Mat frame, curr, prev, curr64f, prev64f, hann;
-    int key = 0;
+    char key;
 
     do
     {
@@ -37,10 +37,10 @@ int main(int, char* [])
         }
 
         imshow("phase shift", frame);
-        key = waitKey(2);
+        key = (char)waitKey(2);
 
         prev = curr.clone();
-    } while((char)key != 27); // Esc to exit...
+    } while(key != 27); // Esc to exit...
 
     return 0;
 }
diff --git a/samples/cpp/points_classifier.cpp b/samples/cpp/points_classifier.cpp
index c0270d084c..9945ba24f6 100644
--- a/samples/cpp/points_classifier.cpp
+++ b/samples/cpp/points_classifier.cpp
@@ -312,7 +312,7 @@ int main()
 
     for(;;)
     {
-        uchar key = (uchar)waitKey();
+        char key = (char)waitKey();
 
         if( key == 27 ) break;
 
diff --git a/samples/cpp/segment_objects.cpp b/samples/cpp/segment_objects.cpp
index 916283124f..32b2598740 100644
--- a/samples/cpp/segment_objects.cpp
+++ b/samples/cpp/segment_objects.cpp
@@ -105,7 +105,7 @@ int main(int argc, char** argv)
         refineSegments(tmp_frame, bgmask, out_frame);
         imshow("video", tmp_frame);
         imshow("segmented", out_frame);
-        int keycode = waitKey(30);
+        char keycode = (char)waitKey(30);
         if( keycode == 27 )
             break;
         if( keycode == ' ' )
diff --git a/samples/cpp/select3dobj.cpp b/samples/cpp/select3dobj.cpp
index b13697fec2..7df366b756 100644
--- a/samples/cpp/select3dobj.cpp
+++ b/samples/cpp/select3dobj.cpp
@@ -285,8 +285,8 @@ static int select3DBox(const string& windowname, const string& selWinName, const
         imshow(windowname, shownFrame);
         imshow(selWinName, selectedObjFrame);
 
-        int c = waitKey(30);
-        if( (c & 255) == 27 )
+        char c = (char)waitKey(30);
+        if( c == 27 )
         {
             nobjpt = 0;
         }
@@ -593,7 +593,7 @@ int main(int argc, char** argv)
 
         imshow("View", shownFrame);
         imshow("Selected Object", selectedObjFrame);
-        int c = waitKey(imageList.empty() && !box.empty() ? 30 : 300);
+        char c = (char)waitKey(imageList.empty() && !box.empty() ? 30 : 300);
         if( c == 'q' || c == 'Q' )
             break;
         if( c == '\r' || c == '\n' )
diff --git a/samples/cpp/smiledetect.cpp b/samples/cpp/smiledetect.cpp
index f2f0bbf076..9e0c3c8d92 100644
--- a/samples/cpp/smiledetect.cpp
+++ b/samples/cpp/smiledetect.cpp
@@ -99,7 +99,7 @@ int main( int argc, const char** argv )
             Mat frame1 = frame.clone();
             detectAndDraw( frame1, cascade, nestedCascade, scale, tryflip );
 
-            int c = waitKey(10);
+            char c = (char)waitKey(10);
             if( c == 27 || c == 'q' || c == 'Q' )
                 break;
         }
diff --git a/samples/cpp/squares.cpp b/samples/cpp/squares.cpp
index df8459caa4..dfa3c61e85 100644
--- a/samples/cpp/squares.cpp
+++ b/samples/cpp/squares.cpp
@@ -167,8 +167,8 @@ int main(int argc, char** argv)
         findSquares(image, squares);
         drawSquares(image, squares);
 
-        int c = waitKey();
-        if( (char)c == 27 )
+        char c = (char)waitKey();
+        if( c == 27 )
             break;
     }
 
diff --git a/samples/cpp/tutorial_code/ImgProc/Pyramids.cpp b/samples/cpp/tutorial_code/ImgProc/Pyramids.cpp
index d8067f9869..62c2fe5c01 100644
--- a/samples/cpp/tutorial_code/ImgProc/Pyramids.cpp
+++ b/samples/cpp/tutorial_code/ImgProc/Pyramids.cpp
@@ -45,26 +45,22 @@ int main( void )
   //![infinite_loop]
   for(;;)
   {
-    int c;
-    c = waitKey(0);
+    char c = (char)waitKey(0);
 
-    if( (char)c == 27 )
+    if( c == 27 )
       { break; }
-    if( (char)c == 'u' )
-      {
-        //![pyrup]
-        pyrUp( tmp, dst, Size( tmp.cols*2, tmp.rows*2 ) );
-        //![pyrup]
+    //![pyrup]
+    if( c == 'u' )
+      { pyrUp( tmp, dst, Size( tmp.cols*2, tmp.rows*2 ) );
         printf( "** Zoom In: Image x 2 \n" );
       }
-    else if( (char)c == 'd' )
-      {
-        //![pyrdown]
-        pyrDown( tmp, dst, Size( tmp.cols/2, tmp.rows/2 ) );
-        //![pyrdown]
+    //![pyrup]
+    //![pyrdown]
+    else if( c == 'd' )
+      { pyrDown( tmp, dst, Size( tmp.cols/2, tmp.rows/2 ) );
         printf( "** Zoom Out: Image / 2 \n" );
       }
-
+    //![pyrdown]
     imshow( window_name, dst );
 
     //![update_tmp]
diff --git a/samples/cpp/tutorial_code/ImgProc/Threshold.cpp b/samples/cpp/tutorial_code/ImgProc/Threshold.cpp
index cee1a51c9c..d057ebcdcf 100644
--- a/samples/cpp/tutorial_code/ImgProc/Threshold.cpp
+++ b/samples/cpp/tutorial_code/ImgProc/Threshold.cpp
@@ -60,9 +60,8 @@ int main( int, char** argv )
   /// Wait until user finishes program
   for(;;)
     {
-      int c;
-      c = waitKey( 20 );
-      if( (char)c == 27 )
+      char c = (char)waitKey( 20 );
+      if( c == 27 )
     { break; }
     }
 
diff --git a/samples/cpp/tutorial_code/ImgProc/Threshold_inRange.cpp b/samples/cpp/tutorial_code/ImgProc/Threshold_inRange.cpp
index 3801b30e7b..8935a04c6d 100644
--- a/samples/cpp/tutorial_code/ImgProc/Threshold_inRange.cpp
+++ b/samples/cpp/tutorial_code/ImgProc/Threshold_inRange.cpp
@@ -41,7 +41,7 @@ int main()
     createTrackbar("Low B","Object Detection", &low_b, 255, on_low_b_thresh_trackbar);
     createTrackbar("High B","Object Detection", &high_b, 255, on_high_b_thresh_trackbar);
     //! [trackbar]
-    while(char(waitKey(1))!='q'){
+    while((char)waitKey(1)!='q'){
         //! [while]
         cap>>frame;
         if(frame.empty())
diff --git a/samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp b/samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp
index 81bb3f8895..2911b9d1c0 100644
--- a/samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp
+++ b/samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp
@@ -90,7 +90,7 @@ int main(int argc, char** argv)
     // infinite loop to display
     // and refresh the content of the output image
     // until the user presses q or Q
-    int key = 0;
+    char key = 0;
     while(key != 'q' && key != 'Q')
     {
         // those paramaters cannot be =0
@@ -102,7 +102,7 @@ int main(int argc, char** argv)
         HoughDetection(src_gray, src, cannyThreshold, accumulatorThreshold);
 
         // get user key
-        key = waitKey(10);
+        key = (char)waitKey(10);
     }
 
     return 0;
diff --git a/samples/cpp/tutorial_code/ImgTrans/Remap_Demo.cpp b/samples/cpp/tutorial_code/ImgTrans/Remap_Demo.cpp
index b5a76faa47..afe7024e75 100644
--- a/samples/cpp/tutorial_code/ImgTrans/Remap_Demo.cpp
+++ b/samples/cpp/tutorial_code/ImgTrans/Remap_Demo.cpp
@@ -40,9 +40,9 @@ int main( int, char** argv )
   for(;;)
   {
     /// Each 1 sec. Press ESC to exit the program
-    int c = waitKey( 1000 );
+    char c = (char)waitKey( 1000 );
 
-    if( (char)c == 27 )
+    if( c == 27 )
       { break; }
 
     /// Update map_x & map_y. Then apply remap
diff --git a/samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp b/samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp
index 60a6d9fcb5..3b9ad0d5ce 100644
--- a/samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp
+++ b/samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp
@@ -23,9 +23,6 @@ RNG rng(12345);
  */
 int main( int, char** argv )
 {
-
-  int c;
-
   //![load]
   src = imread( argv[1], IMREAD_COLOR ); // Load an image
 
@@ -59,13 +56,12 @@ int main( int, char** argv )
   for(;;)
        {
          //![check_keypress]
-         c = waitKey(500);
-
-         if( (char)c == 27 )
+         char c = (char)waitKey(500);
+         if( c == 27 )
            { break; }
-         else if( (char)c == 'c' )
+         else if( c == 'c' )
            { borderType = BORDER_CONSTANT; }
-         else if( (char)c == 'r' )
+         else if( c == 'r' )
            { borderType = BORDER_REPLICATE; }
          //![check_keypress]
 
diff --git a/samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp b/samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp
index e1ceb0bf6d..81a6fc002f 100644
--- a/samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp
+++ b/samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp
@@ -25,8 +25,6 @@ int main ( int, char** argv )
   int kernel_size;
   const char* window_name = "filter2D Demo";
 
-  int c;
-
   //![load]
   src = imread( argv[1], IMREAD_COLOR ); // Load an image
 
@@ -45,9 +43,9 @@ int main ( int, char** argv )
   int ind = 0;
   for(;;)
        {
-         c = waitKey(500);
+         char c = (char)waitKey(500);
          /// Press 'ESC' to exit the program
-         if( (char)c == 27 )
+         if( c == 27 )
            { break; }
 
          //![update_kernel]
diff --git a/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp b/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp
index 4808e64135..de6f72bdbc 100644
--- a/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp
+++ b/samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp
@@ -180,7 +180,7 @@ int main(int argc, char *argv[])
 
   Mat frame, frame_vis;
 
-  while(cap.read(frame) && waitKey(30) != 27) // capture frame until ESC is pressed
+  while(cap.read(frame) && (char)waitKey(30) != 27) // capture frame until ESC is pressed
   {
 
     frame_vis = frame.clone();    // refresh visualisation frame
diff --git a/samples/cpp/tutorial_code/features2D/AKAZE_tracking/planar_tracking.cpp b/samples/cpp/tutorial_code/features2D/AKAZE_tracking/planar_tracking.cpp
index 4920e428cf..77bd9a6894 100755
--- a/samples/cpp/tutorial_code/features2D/AKAZE_tracking/planar_tracking.cpp
+++ b/samples/cpp/tutorial_code/features2D/AKAZE_tracking/planar_tracking.cpp
@@ -195,7 +195,7 @@ int main(int argc, char **argv)
         drawStatistics(orb_res, orb_draw_stats);
         vconcat(akaze_res, orb_res, res_frame);
         cv::imshow(video_name, res_frame);
-        if(cv::waitKey(1)==27) break; //quit on ESC button
+        if(waitKey(1)==27) break; //quit on ESC button
     }
     akaze_stats /= i - 1;
     orb_stats /= i - 1;
diff --git a/samples/cpp/tutorial_code/objectDetection/objectDetection.cpp b/samples/cpp/tutorial_code/objectDetection/objectDetection.cpp
index fbd76e4f08..fe321ec21d 100644
--- a/samples/cpp/tutorial_code/objectDetection/objectDetection.cpp
+++ b/samples/cpp/tutorial_code/objectDetection/objectDetection.cpp
@@ -44,8 +44,8 @@ int main( void )
         //-- 3. Apply the classifier to the frame
         detectAndDisplay( frame );
 
-        int c = waitKey(10);
-        if( (char)c == 27 ) { break; } // escape
+        char c = (char)waitKey(10);
+        if( c == 27 ) { break; } // escape
     }
     return 0;
 }
diff --git a/samples/cpp/tutorial_code/objectDetection/objectDetection2.cpp b/samples/cpp/tutorial_code/objectDetection/objectDetection2.cpp
index d28fa2bba6..e57139b18a 100644
--- a/samples/cpp/tutorial_code/objectDetection/objectDetection2.cpp
+++ b/samples/cpp/tutorial_code/objectDetection/objectDetection2.cpp
@@ -51,8 +51,8 @@ int main( void )
         detectAndDisplay( frame );
 
         //-- bail out if escape was pressed
-        int c = waitKey(10);
-        if( (char)c == 27 ) { break; }
+        char c = (char)waitKey(10);
+        if( c == 27 ) { break; }
     }
     return 0;
 }
diff --git a/samples/cpp/tutorial_code/photo/seamless_cloning/cloning_gui.cpp b/samples/cpp/tutorial_code/photo/seamless_cloning/cloning_gui.cpp
index 180cd69ce2..38ce2959a2 100644
--- a/samples/cpp/tutorial_code/photo/seamless_cloning/cloning_gui.cpp
+++ b/samples/cpp/tutorial_code/photo/seamless_cloning/cloning_gui.cpp
@@ -452,7 +452,7 @@ int main()
 
     for(;;)
     {
-        char key = (char) waitKey(0);
+        char key = (char)waitKey(0);
 
         if(key == 'd' && flag3 == 0)
         {
diff --git a/samples/cpp/tutorial_code/video/bg_sub.cpp b/samples/cpp/tutorial_code/video/bg_sub.cpp
index 94799f388b..bd511eb702 100644
--- a/samples/cpp/tutorial_code/video/bg_sub.cpp
+++ b/samples/cpp/tutorial_code/video/bg_sub.cpp
@@ -23,7 +23,7 @@ using namespace std;
 Mat frame; //current frame
 Mat fgMaskMOG2; //fg mask fg mask generated by MOG2 method
 Ptr<BackgroundSubtractor> pMOG2; //MOG2 Background subtractor
-int keyboard; //input from keyboard
+char keyboard; //input from keyboard
 
 /** Function Headers */
 void help();
@@ -98,7 +98,8 @@ void processVideo(char* videoFilename) {
         exit(EXIT_FAILURE);
     }
     //read input data. ESC or 'q' for quitting
-    while( (char)keyboard != 'q' && (char)keyboard != 27 ){
+    keyboard = 0;
+    while( keyboard != 'q' && keyboard != 27 ){
         //read the current frame
         if(!capture.read(frame)) {
             cerr << "Unable to read next frame." << endl;
@@ -119,7 +120,7 @@ void processVideo(char* videoFilename) {
         imshow("Frame", frame);
         imshow("FG Mask MOG 2", fgMaskMOG2);
         //get the input from the keyboard
-        keyboard = waitKey( 30 );
+        keyboard = (char)waitKey( 30 );
     }
     //delete capture object
     capture.release();
@@ -139,7 +140,8 @@ void processImages(char* fistFrameFilename) {
     //current image filename
     string fn(fistFrameFilename);
     //read input data. ESC or 'q' for quitting
-    while( (char)keyboard != 'q' && (char)keyboard != 27 ){
+    keyboard = 0;
+    while( keyboard != 'q' && keyboard != 27 ){
         //update the background model
         pMOG2->apply(frame, fgMaskMOG2);
         //get the frame number and write it on the current frame
@@ -162,7 +164,7 @@ void processImages(char* fistFrameFilename) {
         imshow("Frame", frame);
         imshow("FG Mask MOG 2", fgMaskMOG2);
         //get the input from the keyboard
-        keyboard = waitKey( 30 );
+        keyboard = (char)waitKey( 30 );
         //search for the next image in the sequence
         ostringstream oss;
         oss << (frameNumber + 1);
diff --git a/samples/cpp/tutorial_code/videoio/video-input-psnr-ssim/video-input-psnr-ssim.cpp b/samples/cpp/tutorial_code/videoio/video-input-psnr-ssim/video-input-psnr-ssim.cpp
index d3f3c21c09..be0b1a8a21 100644
--- a/samples/cpp/tutorial_code/videoio/video-input-psnr-ssim/video-input-psnr-ssim.cpp
+++ b/samples/cpp/tutorial_code/videoio/video-input-psnr-ssim/video-input-psnr-ssim.cpp
@@ -44,7 +44,6 @@ int main(int argc, char *argv[])
     conv << argv[3] << endl << argv[4];       // put in the strings
     conv >> psnrTriggerValue >> delay;        // take out the numbers
 
-    char c;
     int frameNum = -1;          // Frame counter
 
     VideoCapture captRefrnc(sourceReference), captUndTst(sourceCompareWith);
@@ -126,7 +125,7 @@ int main(int argc, char *argv[])
         imshow(WIN_RF, frameReference);
         imshow(WIN_UT, frameUnderTest);
 
-        c = (char)waitKey(delay);
+        char c = (char)waitKey(delay);
         if (c == 27) break;
     }
 
diff --git a/samples/cpp/watershed.cpp b/samples/cpp/watershed.cpp
index 9f2e69ec6b..0991bb0424 100644
--- a/samples/cpp/watershed.cpp
+++ b/samples/cpp/watershed.cpp
@@ -74,19 +74,19 @@ int main( int argc, char** argv )
 
     for(;;)
     {
-        int c = waitKey(0);
+        char c = (char)waitKey(0);
 
-        if( (char)c == 27 )
+        if( c == 27 )
             break;
 
-        if( (char)c == 'r' )
+        if( c == 'r' )
         {
             markerMask = Scalar::all(0);
             img0.copyTo(img);
             imshow( "image", img );
         }
 
-        if( (char)c == 'w' || (char)c == ' ' )
+        if( c == 'w' || c == ' ' )
         {
             int i, j, compCount = 0;
             vector<vector<Point> > contours;
diff --git a/samples/gpu/bgfg_segm.cpp b/samples/gpu/bgfg_segm.cpp
index 5383db7f0f..b7d9d7e9ae 100644
--- a/samples/gpu/bgfg_segm.cpp
+++ b/samples/gpu/bgfg_segm.cpp
@@ -161,7 +161,7 @@ int main(int argc, const char** argv)
         if (!bgimg.empty())
             imshow("mean background image", bgimg);
 
-        int key = waitKey(30);
+        char key = (char)waitKey(30);
         if (key == 27)
             break;
     }
diff --git a/samples/gpu/opengl.cpp b/samples/gpu/opengl.cpp
index 9e2c68c432..6bed4e367d 100644
--- a/samples/gpu/opengl.cpp
+++ b/samples/gpu/opengl.cpp
@@ -105,8 +105,8 @@ int main(int argc, char* argv[])
     for (;;)
     {
         updateWindow("OpenGL");
-        int key = waitKey(40);
-        if ((key & 0xff) == 27)
+        char key = (char)waitKey(40);
+        if (key == 27)
             break;
     }
 
diff --git a/samples/python/camshift.py b/samples/python/camshift.py
index d1298b9c27..d55c1ac76c 100755
--- a/samples/python/camshift.py
+++ b/samples/python/camshift.py
@@ -110,7 +110,7 @@ class App(object):
 
             cv2.imshow('camshift', vis)
 
-            ch = 0xFF & cv2.waitKey(5)
+            ch = cv2.waitKey(5)
             if ch == 27:
                 break
             if ch == ord('b'):
diff --git a/samples/python/coherence.py b/samples/python/coherence.py
index 8ca61fcb21..a1e34b86f4 100755
--- a/samples/python/coherence.py
+++ b/samples/python/coherence.py
@@ -77,7 +77,7 @@ if __name__ == '__main__':
     cv2.imshow('src', src)
     update()
     while True:
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == ord(' '):
             update()
         if ch == 27:
diff --git a/samples/python/color_histogram.py b/samples/python/color_histogram.py
index 9e691b7efe..c1e5d56e4c 100755
--- a/samples/python/color_histogram.py
+++ b/samples/python/color_histogram.py
@@ -56,7 +56,7 @@ if __name__ == '__main__':
         vis = hsv_map*h[:,:,np.newaxis] / 255.0
         cv2.imshow('hist', vis)
 
-        ch = 0xFF & cv2.waitKey(1)
+        ch = cv2.waitKey(1)
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/contours.py b/samples/python/contours.py
index 619108b245..73b9f2f821 100755
--- a/samples/python/contours.py
+++ b/samples/python/contours.py
@@ -66,5 +66,5 @@ if __name__ == '__main__':
     update(3)
     cv2.createTrackbar( "levels+3", "contours", 3, 7, update )
     cv2.imshow('image', img)
-    0xFF & cv2.waitKey()
+    cv2.waitKey()
     cv2.destroyAllWindows()
diff --git a/samples/python/deconvolution.py b/samples/python/deconvolution.py
index ce798538b8..74f51a714b 100755
--- a/samples/python/deconvolution.py
+++ b/samples/python/deconvolution.py
@@ -122,7 +122,7 @@ if __name__ == '__main__':
     update(None)
 
     while True:
-        ch = cv2.waitKey() & 0xFF
+        ch = cv2.waitKey()
         if ch == 27:
             break
         if ch == ord(' '):
diff --git a/samples/python/digits_video.py b/samples/python/digits_video.py
index 74b9d6993b..2f79cb5cc0 100755
--- a/samples/python/digits_video.py
+++ b/samples/python/digits_video.py
@@ -92,7 +92,7 @@ def main():
 
         cv2.imshow('frame', frame)
         cv2.imshow('bin', bin)
-        ch = cv2.waitKey(1) & 0xFF
+        ch = cv2.waitKey(1)
         if ch == 27:
             break
 
diff --git a/samples/python/distrans.py b/samples/python/distrans.py
index 00e173d523..8abe460eda 100755
--- a/samples/python/distrans.py
+++ b/samples/python/distrans.py
@@ -59,7 +59,7 @@ if __name__ == '__main__':
 
 
     while True:
-        ch = 0xFF & cv2.waitKey(50)
+        ch = cv2.waitKey(50)
         if ch == 27:
             break
         if ch == ord('v'):
diff --git a/samples/python/edge.py b/samples/python/edge.py
index c096fb46a7..b597729ee9 100755
--- a/samples/python/edge.py
+++ b/samples/python/edge.py
@@ -49,7 +49,7 @@ if __name__ == '__main__':
         vis = np.uint8(vis/2.)
         vis[edge != 0] = (0, 255, 0)
         cv2.imshow('edge', vis)
-        ch = cv2.waitKey(5) & 0xFF
+        ch = cv2.waitKey(5)
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/facedetect.py b/samples/python/facedetect.py
index 15187c62f4..0f79663d7b 100755
--- a/samples/python/facedetect.py
+++ b/samples/python/facedetect.py
@@ -68,6 +68,6 @@ if __name__ == '__main__':
         draw_str(vis, (20, 20), 'time: %.1f ms' % (dt*1000))
         cv2.imshow('facedetect', vis)
 
-        if 0xFF & cv2.waitKey(5) == 27:
+        if cv2.waitKey(5) == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/fitline.py b/samples/python/fitline.py
index 95fb2b8d10..c91144c2a0 100755
--- a/samples/python/fitline.py
+++ b/samples/python/fitline.py
@@ -88,7 +88,7 @@ if __name__ == '__main__':
     cv2.createTrackbar('outlier %', 'fit line', 30, 100, update)
     while True:
         update()
-        ch = cv2.waitKey(0) & 0xFF
+        ch = cv2.waitKey(0)
         if ch == ord('f'):
             if PY3:
                 cur_func_name = next(dist_func_names)
diff --git a/samples/python/floodfill.py b/samples/python/floodfill.py
index 161c6323f4..1b988d3763 100755
--- a/samples/python/floodfill.py
+++ b/samples/python/floodfill.py
@@ -66,7 +66,7 @@ if __name__ == '__main__':
     cv2.createTrackbar('hi', 'floodfill', 20, 255, update)
 
     while True:
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == 27:
             break
         if ch == ord('f'):
diff --git a/samples/python/gaussian_mix.py b/samples/python/gaussian_mix.py
index 64fbe23462..79c69fcdc1 100755
--- a/samples/python/gaussian_mix.py
+++ b/samples/python/gaussian_mix.py
@@ -63,7 +63,7 @@ if __name__ == '__main__':
             draw_gaussain(img, m, cov, (0, 0, 255))
 
         cv2.imshow('gaussian mixture', img)
-        ch = 0xFF & cv2.waitKey(0)
+        ch = cv2.waitKey(0)
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/grabcut.py b/samples/python/grabcut.py
index 19378e6cce..1a5c2d0b3a 100644
--- a/samples/python/grabcut.py
+++ b/samples/python/grabcut.py
@@ -129,7 +129,7 @@ if __name__ == '__main__':
 
         cv2.imshow('output',output)
         cv2.imshow('input',img)
-        k = 0xFF & cv2.waitKey(1)
+        k = cv2.waitKey(1)
 
         # key bindings
         if k == 27:         # esc to exit
diff --git a/samples/python/hist.py b/samples/python/hist.py
index 80cc6b4802..d1801c7e1b 100755
--- a/samples/python/hist.py
+++ b/samples/python/hist.py
@@ -84,7 +84,7 @@ if __name__ == '__main__':
 
     cv2.imshow('image',im)
     while True:
-        k = cv2.waitKey(0)&0xFF
+        k = cv2.waitKey(0)
         if k == ord('a'):
             curve = hist_curve(im)
             cv2.imshow('histogram',curve)
diff --git a/samples/python/inpaint.py b/samples/python/inpaint.py
index 0ca72f1a25..3b738bb141 100755
--- a/samples/python/inpaint.py
+++ b/samples/python/inpaint.py
@@ -41,7 +41,7 @@ if __name__ == '__main__':
     sketch = Sketcher('img', [img_mark, mark], lambda : ((255, 255, 255), 255))
 
     while True:
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == 27:
             break
         if ch == ord(' '):
diff --git a/samples/python/kalman.py b/samples/python/kalman.py
index be361ff068..96a6fa6fe4 100755
--- a/samples/python/kalman.py
+++ b/samples/python/kalman.py
@@ -90,7 +90,7 @@ if __name__ == "__main__":
             if code != -1:
                 break
 
-        if (code % 0x100) in [27, ord('q'), ord('Q')]:
+        if code in [27, ord('q'), ord('Q')]:
             break
 
     cv2.destroyWindow("Kalman")
diff --git a/samples/python/kmeans.py b/samples/python/kmeans.py
index b2e6b6618d..0fdc759b4e 100755
--- a/samples/python/kmeans.py
+++ b/samples/python/kmeans.py
@@ -44,7 +44,7 @@ if __name__ == '__main__':
             cv2.circle(img, (x, y), 1, c, -1)
 
         cv2.imshow('gaussian mixture', img)
-        ch = 0xFF & cv2.waitKey(0)
+        ch = cv2.waitKey(0)
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/lappyr.py b/samples/python/lappyr.py
index d8fde0f004..c68e5e8126 100755
--- a/samples/python/lappyr.py
+++ b/samples/python/lappyr.py
@@ -70,5 +70,5 @@ if __name__ == '__main__':
 
         cv2.imshow('laplacian pyramid filter', res)
 
-        if cv2.waitKey(1) & 0xFF == 27:
+        if cv2.waitKey(1) == 27:
             break
diff --git a/samples/python/lk_homography.py b/samples/python/lk_homography.py
index 3b940e415f..8cc3b695a7 100755
--- a/samples/python/lk_homography.py
+++ b/samples/python/lk_homography.py
@@ -90,7 +90,7 @@ class App:
 
             cv2.imshow('lk_homography', vis)
 
-            ch = 0xFF & cv2.waitKey(1)
+            ch = cv2.waitKey(1)
             if ch == 27:
                 break
             if ch == ord(' '):
diff --git a/samples/python/lk_track.py b/samples/python/lk_track.py
index 8aa94fe642..ffa7dfa248 100755
--- a/samples/python/lk_track.py
+++ b/samples/python/lk_track.py
@@ -85,7 +85,7 @@ class App:
             self.prev_gray = frame_gray
             cv2.imshow('lk_track', vis)
 
-            ch = 0xFF & cv2.waitKey(1)
+            ch = cv2.waitKey(1)
             if ch == 27:
                 break
 
diff --git a/samples/python/morphology.py b/samples/python/morphology.py
index be287d33d4..0b62784d2f 100755
--- a/samples/python/morphology.py
+++ b/samples/python/morphology.py
@@ -79,7 +79,7 @@ if __name__ == '__main__':
     cv2.createTrackbar('iters', 'morphology', 1, 10, update)
     update()
     while True:
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == 27:
             break
         if ch == ord('1'):
diff --git a/samples/python/mosse.py b/samples/python/mosse.py
index 29a3a697f1..46e22d3c06 100755
--- a/samples/python/mosse.py
+++ b/samples/python/mosse.py
@@ -176,7 +176,7 @@ class App:
             self.rect_sel.draw(vis)
 
             cv2.imshow('frame', vis)
-            ch = cv2.waitKey(10) & 0xFF
+            ch = cv2.waitKey(10)
             if ch == 27:
                 break
             if ch == ord(' '):
diff --git a/samples/python/mouse_and_match.py b/samples/python/mouse_and_match.py
index adbd8babee..f75b64cabf 100755
--- a/samples/python/mouse_and_match.py
+++ b/samples/python/mouse_and_match.py
@@ -78,6 +78,6 @@ if __name__ == '__main__':
             drag_start = None
             gray=cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
             cv2.imshow("gray",gray)
-            if (cv2.waitKey() & 255) == 27:
+            if cv2.waitKey() == 27:
                 break
     cv2.destroyAllWindows()
diff --git a/samples/python/mser.py b/samples/python/mser.py
index 1f0cb046a7..1c5c69bd9a 100755
--- a/samples/python/mser.py
+++ b/samples/python/mser.py
@@ -40,6 +40,6 @@ if __name__ == '__main__':
         cv2.polylines(vis, hulls, 1, (0, 255, 0))
 
         cv2.imshow('img', vis)
-        if 0xFF & cv2.waitKey(5) == 27:
+        if cv2.waitKey(5) == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/opt_flow.py b/samples/python/opt_flow.py
index be85262c91..3d4ef34dc2 100755
--- a/samples/python/opt_flow.py
+++ b/samples/python/opt_flow.py
@@ -83,7 +83,7 @@ if __name__ == '__main__':
             cur_glitch = warp_flow(cur_glitch, flow)
             cv2.imshow('glitch', cur_glitch)
 
-        ch = 0xFF & cv2.waitKey(5)
+        ch = cv2.waitKey(5)
         if ch == 27:
             break
         if ch == ord('1'):
diff --git a/samples/python/peopledetect.py b/samples/python/peopledetect.py
index 1cad95288b..84db09639e 100755
--- a/samples/python/peopledetect.py
+++ b/samples/python/peopledetect.py
@@ -65,7 +65,7 @@ if __name__ == '__main__':
         draw_detections(img, found_filtered, 3)
         print('%d (%d) found' % (len(found_filtered), len(found)))
         cv2.imshow('img', img)
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/plane_ar.py b/samples/python/plane_ar.py
index 7f2969cdd8..8994833c09 100755
--- a/samples/python/plane_ar.py
+++ b/samples/python/plane_ar.py
@@ -75,7 +75,7 @@ class App:
 
             self.rect_sel.draw(vis)
             cv2.imshow('plane', vis)
-            ch = cv2.waitKey(1) & 0xFF
+            ch = cv2.waitKey(1)
             if ch == ord(' '):
                 self.paused = not self.paused
             if ch == ord('c'):
diff --git a/samples/python/plane_tracker.py b/samples/python/plane_tracker.py
index f66f3829c8..e285c085d7 100755
--- a/samples/python/plane_tracker.py
+++ b/samples/python/plane_tracker.py
@@ -170,7 +170,7 @@ class App:
 
             self.rect_sel.draw(vis)
             cv2.imshow('plane', vis)
-            ch = cv2.waitKey(1) & 0xFF
+            ch = cv2.waitKey(1)
             if ch == ord(' '):
                 self.paused = not self.paused
             if ch == ord('c'):
diff --git a/samples/python/squares.py b/samples/python/squares.py
index cc33144deb..be28f1a3e7 100755
--- a/samples/python/squares.py
+++ b/samples/python/squares.py
@@ -49,7 +49,7 @@ if __name__ == '__main__':
         squares = find_squares(img)
         cv2.drawContours( img, squares, -1, (0, 255, 0), 3 )
         cv2.imshow('squares', img)
-        ch = 0xFF & cv2.waitKey()
+        ch = cv2.waitKey()
         if ch == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/tst_scene_render.py b/samples/python/tst_scene_render.py
index 78ce478a12..ce956f59d2 100644
--- a/samples/python/tst_scene_render.py
+++ b/samples/python/tst_scene_render.py
@@ -108,9 +108,9 @@ if __name__ == '__main__':
         img = render.getNextFrame()
         cv2.imshow('img', img)
 
-        ch = 0xFF & cv2.waitKey(3)
+        ch = cv2.waitKey(3)
         if  ch == 27:
             break
     #import os
     #print (os.environ['PYTHONPATH'])
-    cv2.destroyAllWindows()
\ No newline at end of file
+    cv2.destroyAllWindows()
diff --git a/samples/python/turing.py b/samples/python/turing.py
index f9926ba909..5733d056bd 100755
--- a/samples/python/turing.py
+++ b/samples/python/turing.py
@@ -69,6 +69,6 @@ if __name__ == '__main__':
         vis = a.copy()
         draw_str(vis, (20, 20), 'frame %d' % frame_i)
         cv2.imshow('a', vis)
-        if 0xFF & cv2.waitKey(5) == 27:
+        if cv2.waitKey(5) == 27:
             break
     cv2.destroyAllWindows()
diff --git a/samples/python/video.py b/samples/python/video.py
index bc0348fd93..be15641b11 100755
--- a/samples/python/video.py
+++ b/samples/python/video.py
@@ -217,7 +217,7 @@ if __name__ == '__main__':
             ret, img = cap.read()
             imgs.append(img)
             cv2.imshow('capture %d' % i, img)
-        ch = 0xFF & cv2.waitKey(1)
+        ch = cv2.waitKey(1)
         if ch == 27:
             break
         if ch == ord(' '):
diff --git a/samples/python/video_threaded.py b/samples/python/video_threaded.py
index 76d764b62d..896a5c3e99 100755
--- a/samples/python/video_threaded.py
+++ b/samples/python/video_threaded.py
@@ -81,7 +81,7 @@ if __name__ == '__main__':
             else:
                 task = DummyTask(process_frame(frame, t))
             pending.append(task)
-        ch = 0xFF & cv2.waitKey(1)
+        ch = cv2.waitKey(1)
         if ch == ord(' '):
             threaded_mode = not threaded_mode
         if ch == 27:
diff --git a/samples/python/video_v4l2.py b/samples/python/video_v4l2.py
index eed22d11b8..0af68e5d9d 100644
--- a/samples/python/video_v4l2.py
+++ b/samples/python/video_v4l2.py
@@ -58,10 +58,10 @@ while True:
     cv2.putText(img, "FPS: {}".format(fps), (15, 80), font, 1.0, color)
     cv2.imshow("Video", img)
 
-    k = 0xFF & cv2.waitKey(1)
+    k = cv2.waitKey(1)
 
     if k == 27:
         break
-    elif k == ord("g"):
+    elif k == ord('g'):
         convert_rgb = not convert_rgb
         cap.set(cv2.CAP_PROP_CONVERT_RGB, convert_rgb)
diff --git a/samples/python/watershed.py b/samples/python/watershed.py
index 134e499301..30be82cf0c 100755
--- a/samples/python/watershed.py
+++ b/samples/python/watershed.py
@@ -56,7 +56,7 @@ class App:
 
     def run(self):
         while cv2.getWindowProperty('img', 0) != -1 or cv2.getWindowProperty('watershed', 0) != -1:
-            ch = 0xFF & cv2.waitKey(50)
+            ch = cv2.waitKey(50)
             if ch == 27:
                 break
             if ch >= ord('1') and ch <= ord('7'):
diff --git a/samples/tapi/ufacedetect.cpp b/samples/tapi/ufacedetect.cpp
index 760ee7090d..874300ab77 100644
--- a/samples/tapi/ufacedetect.cpp
+++ b/samples/tapi/ufacedetect.cpp
@@ -78,9 +78,9 @@ int main( int argc, const char** argv )
 
     if( inputName.empty() || (isdigit(inputName[0]) && inputName.size() == 1) )
     {
-        int c = inputName.empty() ? 0 : inputName[0] - '0';
-        if(!capture.open(c))
-            cout << "Capture from camera #" <<  c << " didn't work" << endl;
+        int camera = inputName.empty() ? 0 : inputName[0] - '0';
+        if(!capture.open(camera))
+            cout << "Capture from camera #" <<  camera << " didn't work" << endl;
     }
     else
     {
@@ -105,7 +105,7 @@ int main( int argc, const char** argv )
 
             detectAndDraw( frame, canvas, cascade, nestedCascade, scale, tryflip );
 
-            int c = waitKey(10);
+            char c = (char)waitKey(10);
             if( c == 27 || c == 'q' || c == 'Q' )
                 break;
         }
@@ -128,7 +128,7 @@ int main( int argc, const char** argv )
                 char buf[1000+1];
                 while( fgets( buf, 1000, f ) )
                 {
-                    int len = (int)strlen(buf), c;
+                    int len = (int)strlen(buf);
                     while( len > 0 && isspace(buf[len-1]) )
                         len--;
                     buf[len] = '\0';
@@ -137,7 +137,7 @@ int main( int argc, const char** argv )
                     if( !image.empty() )
                     {
                         detectAndDraw( image, canvas, cascade, nestedCascade, scale, tryflip );
-                        c = waitKey(0);
+                        char c = (char)waitKey(0);
                         if( c == 27 || c == 'q' || c == 'Q' )
                             break;
                     }