Merge pull request #19370 from OlivierLDff:patch-dshow-convertrgb

VideoCapture/DSHOW : Allow to set CAP_PROP_CONVERT_RGB before FOURCC/FPS/CHANNEL/WIDTH/HEIGHT.

* 🐛 cap_dshow : Allow to set CAP_PROP_CONVERT_RGB before FOURCC/FPS/CHANNEL

* 🐛 cap_dshow : fix g_VI.setConvertRGB not being called with correct boolean value on first property set.

* ✅ cap_dshow : Test CAP_PROP_CONVERT_RGB persistence

* 🚨 Fix cast from bool to double

* 🚨 Fix trailing whitespace

modules/videoio/src/cap_dshow.cpp

@@ -3341,6 +3341,7 @@ VideoCapture_DShow::VideoCapture_DShow(int index)
     , m_fourcc(-1)
     , m_widthSet(-1)
     , m_heightSet(-1)
+    , m_convertRGBSet(true)
 {
     CoInitialize(0);
     open(index);
@@ -3450,6 +3451,7 @@ bool VideoCapture_DShow::setProperty(int propIdx, double propVal)
             break;
         g_VI.stopDevice(m_index);
         g_VI.setupDevice(m_index,  cvFloor(propVal));
+        g_VI.setConvertRGB(m_index, m_convertRGBSet);
         break;
 
     case CV_CAP_PROP_FPS:
@@ -3463,6 +3465,7 @@ bool VideoCapture_DShow::setProperty(int propIdx, double propVal)
                 g_VI.setupDevice(m_index, m_widthSet, m_heightSet);
             else
                 g_VI.setupDevice(m_index);
+            g_VI.setConvertRGB(m_index, m_convertRGBSet);
         }
         return g_VI.isDeviceSetup(m_index);
     }
@@ -3481,7 +3484,11 @@ bool VideoCapture_DShow::setProperty(int propIdx, double propVal)
 
     case CV_CAP_PROP_CONVERT_RGB:
     {
-        return g_VI.setConvertRGB(m_index, cvRound(propVal) == 1);
+        const bool convertRgb = cvRound(propVal) == 1;
+        const bool success = g_VI.setConvertRGB(m_index, convertRgb);
+        if(success)
+            m_convertRGBSet = convertRgb;
+        return success;
     }
 
     }
@@ -3497,6 +3504,7 @@ bool VideoCapture_DShow::setProperty(int propIdx, double propVal)
                 g_VI.stopDevice(m_index);
                 g_VI.setIdealFramerate(m_index, fps);
                 g_VI.setupDeviceFourcc(m_index, m_width, m_height, m_fourcc);
+                g_VI.setConvertRGB(m_index, m_convertRGBSet);
             }
 
             bool success = g_VI.isDeviceSetup(m_index);
@@ -3602,6 +3610,7 @@ void VideoCapture_DShow::close()
         m_index = -1;
     }
     m_widthSet = m_heightSet = m_width = m_height = -1;
+    m_convertRGBSet = true;
 }
 
 Ptr<IVideoCapture> create_DShow_capture(int index)

modules/videoio/src/cap_dshow.hpp

@@ -37,6 +37,7 @@ protected:
 
     int m_index, m_width, m_height, m_fourcc;
     int m_widthSet, m_heightSet;
+    bool m_convertRGBSet;
     static videoInput g_VI;
 };
 

modules/videoio/test/test_camera.cpp

@@ -72,6 +72,27 @@ TEST(DISABLED_videoio_camera, basic)
     capture.release();
 }
 
+// Test that CAP_PROP_CONVERT_RGB remain to false (default is true) after other supported property are set.
+// The test use odd value to be almost sure to trigger code responsible for recreating the device.
+TEST(DISABLED_videoio_camera, dshow_convert_rgb_persistency)
+{
+    VideoCapture capture(CAP_DSHOW);
+    ASSERT_TRUE(capture.isOpened());
+    ASSERT_TRUE(capture.set(CAP_PROP_CONVERT_RGB, 0));
+    ASSERT_DOUBLE_EQ(capture.get(CAP_PROP_CONVERT_RGB), 0);
+    capture.set(CAP_PROP_FRAME_WIDTH, 641);
+    capture.set(CAP_PROP_FRAME_HEIGHT, 481);
+    capture.set(CAP_PROP_FPS, 31);
+    capture.set(CAP_PROP_CHANNEL, 1);
+    capture.set(cv::CAP_PROP_FOURCC, cv::VideoWriter::fourcc('Y', '1', '6', ' '));
+    std::cout << "Camera 0 via " << capture.getBackendName() << " backend" << std::endl;
+    std::cout << "Frame width: " << capture.get(CAP_PROP_FRAME_WIDTH) << std::endl;
+    std::cout << "     height: " << capture.get(CAP_PROP_FRAME_HEIGHT) << std::endl;
+    std::cout << "Capturing FPS: " << capture.get(CAP_PROP_FPS) << std::endl;
+    ASSERT_DOUBLE_EQ(capture.get(CAP_PROP_CONVERT_RGB), 0);
+    capture.release();
+}
+
 TEST(DISABLED_videoio_camera, v4l_read_mjpg)
 {
     VideoCapture capture(CAP_V4L2);