Merge pull request #12623 from sturkmen72:videoio-4

modules/videoio/include/opencv2/videoio.hpp

@@ -617,14 +617,7 @@ public:
     CV_WRAP VideoCapture();
 
     /** @overload
-    @brief  Open video file or a capturing device or a IP video stream for video capturing
-
-    Same as VideoCapture(const String& filename, int apiPreference) but using default Capture API backends
-    */
-    CV_WRAP VideoCapture(const String& filename);
-
-    /** @overload
-    @brief  Open video file or a capturing device or a IP video stream for video capturing with API Preference
+    @brief  Opens a video file or a capturing device or an IP video stream for video capturing with API Preference
 
     @param filename it can be:
     - name of video file (eg. `video.avi`)
@@ -636,18 +629,19 @@ public:
     implementation if multiple are available: e.g. cv::CAP_FFMPEG or cv::CAP_IMAGES or cv::CAP_DSHOW.
     @sa The list of supported API backends cv::VideoCaptureAPIs
     */
-    CV_WRAP VideoCapture(const String& filename, int apiPreference);
+    CV_WRAP VideoCapture(const String& filename, int apiPreference = CAP_ANY);
 
     /** @overload
-    @brief  Open a camera for video capturing
+    @brief  Opens a camera for video capturing
 
-    @param index camera_id + domain_offset (CAP_*) id of the video capturing device to open. To open default camera using default backend just pass 0.
-    Use a `domain_offset` to enforce a specific reader implementation if multiple are available like cv::CAP_FFMPEG or cv::CAP_IMAGES or cv::CAP_DSHOW.
-    e.g. to open Camera 1 using the MS Media Foundation API use `index = 1 + cv::CAP_MSMF`
+    @param index id of the video capturing device to open. To open default camera using default backend just pass 0.
+    (to backward compatibility usage of camera_id + domain_offset (CAP_*) is valid when apiPreference is CAP_ANY)
+    @param apiPreference preferred Capture API backends to use. Can be used to enforce a specific reader
+    implementation if multiple are available: e.g. cv::CAP_DSHOW or cv::CAP_MSMF or cv::CAP_V4L.
 
     @sa The list of supported API backends cv::VideoCaptureAPIs
     */
-    CV_WRAP VideoCapture(int index);
+    CV_WRAP VideoCapture(int index, int apiPreference = CAP_ANY);
 
     /** @brief Default destructor
 
@@ -655,37 +649,27 @@ public:
     */
     virtual ~VideoCapture();
 
-    /** @brief  Open video file or a capturing device or a IP video stream for video capturing
+    /** @brief  Opens a video file or a capturing device or an IP video stream for video capturing.
 
     @overload
 
-    Parameters are same as the constructor VideoCapture(const String& filename)
+    Parameters are same as the constructor VideoCapture(const String& filename, int apiPreference = CAP_ANY)
     @return `true` if the file has been successfully opened
 
     The method first calls VideoCapture::release to close the already opened file or camera.
      */
-    CV_WRAP virtual bool open(const String& filename);
+    CV_WRAP virtual bool open(const String& filename, int apiPreference = CAP_ANY);
 
-    /** @brief  Open a camera for video capturing
+    /** @brief  Opens a camera for video capturing
 
     @overload
 
-    Parameters are same as the constructor VideoCapture(int index)
+    Parameters are same as the constructor VideoCapture(int index, int apiPreference = CAP_ANY)
     @return `true` if the camera has been successfully opened.
 
     The method first calls VideoCapture::release to close the already opened file or camera.
     */
-    CV_WRAP virtual bool open(int index);
-
-   /** @brief  Open a camera for video capturing
-
-    @overload
-
-    Parameters are similar as the constructor VideoCapture(int index),except it takes an additional argument apiPreference.
-    Definitely, is same as open(int index) where `index=cameraNum + apiPreference`
-    @return `true` if the camera has been successfully opened.
-    */
-    CV_WRAP bool open(int cameraNum, int apiPreference);
+    CV_WRAP virtual bool open(int index, int apiPreference = CAP_ANY);
 
     /** @brief Returns true if video capturing has been initialized already.
 
@@ -798,17 +782,6 @@ public:
     */
     CV_WRAP virtual double get(int propId) const;
 
-    /** @brief Open video file or a capturing device or a IP video stream for video capturing with API Preference
-
-    @overload
-
-    Parameters are same as the constructor VideoCapture(const String& filename, int apiPreference)
-    @return `true` if the file has been successfully opened
-
-    The method first calls VideoCapture::release to close the already opened file or camera.
-    */
-    CV_WRAP virtual bool open(const String& filename, int apiPreference);
-
     /** @brief Returns used backend API name
 
      @note Stream should be opened.
@@ -915,6 +888,11 @@ public:
     */
     virtual VideoWriter& operator << (const Mat& image);
 
+    /** @overload
+    @sa write
+    */
+    virtual VideoWriter& operator << (const UMat& image);
+
     /** @brief Writes the next video frame
 
     @param image The written frame. In general, color images are expected in BGR format.
@@ -922,7 +900,7 @@ public:
     The function/method writes the specified image to video file. It must have the same size as has
     been specified when opening the video writer.
      */
-    CV_WRAP virtual void write(const Mat& image);
+    CV_WRAP virtual void write(InputArray image);
 
     /** @brief Sets a property in the VideoWriter.
 

modules/videoio/src/cap.cpp

@@ -59,16 +59,10 @@ VideoCapture::VideoCapture(const String& filename, int apiPreference)
     open(filename, apiPreference);
 }
 
-VideoCapture::VideoCapture(const String& filename)
+VideoCapture::VideoCapture(int index, int apiPreference)
 {
     CV_TRACE_FUNCTION();
-    open(filename, CAP_ANY);
-}
-
-VideoCapture::VideoCapture(int index)
-{
-    CV_TRACE_FUNCTION();
-    open(index);
+    open(index, apiPreference);
 }
 
 VideoCapture::~VideoCapture()
@@ -110,19 +104,23 @@ bool VideoCapture::open(const String& filename, int apiPreference)
     return false;
 }
 
-bool VideoCapture::open(const String& filename)
-{
-    CV_TRACE_FUNCTION();
-
-    return open(filename, CAP_ANY);
-}
-
 bool  VideoCapture::open(int cameraNum, int apiPreference)
 {
     CV_TRACE_FUNCTION();
 
     if (isOpened()) release();
 
+    if(apiPreference==CAP_ANY)
+    {
+        // interpret preferred interface (0 = autodetect)
+        int backendID = (cameraNum / 100) * 100;
+        if (backendID)
+        {
+            cameraNum %= 100;
+            apiPreference = backendID;
+        }
+    }
+
     const std::vector<VideoBackendInfo> backends = cv::videoio_registry::getAvailableBackends_CaptureByIndex();
     for (size_t i = 0; i < backends.size(); i++)
     {
@@ -148,20 +146,6 @@ bool  VideoCapture::open(int cameraNum, int apiPreference)
     return false;
 }
 
-bool VideoCapture::open(int index)
-{
-    CV_TRACE_FUNCTION();
-
-    // interpret preferred interface (0 = autodetect)
-    int backendID = (index / 100) * 100;
-    if (backendID)
-    {
-        index %= 100;
-    }
-
-    return open(index, backendID);
-}
-
 bool VideoCapture::isOpened() const
 {
     if (!icap.empty())
@@ -268,7 +252,7 @@ VideoCapture& VideoCapture::operator >> (UMat& image)
 
 bool VideoCapture::set(int propId, double value)
 {
-    CV_CheckNE(propId, (int)CAP_PROP_BACKEND, "Can set read-only property");
+    CV_CheckNE(propId, (int)CAP_PROP_BACKEND, "Can't set read-only property");
 
     if (!icap.empty())
         return icap->setProperty(propId, value);
@@ -367,7 +351,7 @@ bool VideoWriter::isOpened() const
 
 bool VideoWriter::set(int propId, double value)
 {
-    CV_CheckNE(propId, (int)CAP_PROP_BACKEND, "Can set read-only property");
+    CV_CheckNE(propId, (int)CAP_PROP_BACKEND, "Can't set read-only property");
 
     if (!iwriter.empty())
         return iwriter->setProperty(propId, value);
@@ -403,7 +387,7 @@ String VideoWriter::getBackendName() const
     return cv::videoio_registry::getBackendName((VideoCaptureAPIs)api);
 }
 
-void VideoWriter::write(const Mat& image)
+void VideoWriter::write(InputArray image)
 {
     CV_INSTRUMENT_REGION();
 
@@ -411,7 +395,7 @@ void VideoWriter::write(const Mat& image)
         iwriter->write(image);
     else
     {
-        IplImage _img = cvIplImage(image);
+        IplImage _img = cvIplImage(image.getMat());
         cvWriteFrame(writer, &_img);
     }
 }
@@ -424,6 +408,13 @@ VideoWriter& VideoWriter::operator << (const Mat& image)
     return *this;
 }
 
+VideoWriter& VideoWriter::operator << (const UMat& image)
+{
+    CV_INSTRUMENT_REGION();
+    write(image);
+    return *this;
+}
+
 // FIXIT OpenCV 4.0: make inline
 int VideoWriter::fourcc(char c1, char c2, char c3, char c4)
 {

samples/tapi/hog.cpp

@@ -64,7 +64,7 @@ int main(int argc, char** argv)
         "{ v video     | ../data/vtest.avi | use video as input }"
         "{ g gray      |                | convert image to gray one or not}"
         "{ s scale     | 1.0            | resize the image before detect}"
-        "{ o output    |                | specify output path when input is images}";
+        "{ o output    |   output.avi   | specify output path when input is images}";
     CommandLineParser cmd(argc, argv, keys);
     if (cmd.has("help"))
     {
@@ -175,8 +175,7 @@ void App::run()
                 throw runtime_error(string("can't open image file: " + img_source));
         }
 
-        UMat img_aux, img;
-        Mat img_to_show;
+        UMat img_aux, img, img_to_show;
 
         // Iterate over all frames
         while (running && !frame.empty())
@@ -209,8 +208,7 @@ void App::run()
             // Draw positive classified windows
             for (size_t i = 0; i < found.size(); i++)
             {
-                Rect r = found[i];
-                rectangle(img_to_show, r.tl(), r.br(), Scalar(0, 255, 0), 3);
+                rectangle(img_to_show, found[i], Scalar(0, 255, 0), 3);
             }
 
             putText(img_to_show, ocl::useOpenCL() ? "Mode: OpenCL"  : "Mode: CPU", Point(5, 25), FONT_HERSHEY_SIMPLEX, 1., Scalar(255, 100, 0), 2);
@@ -241,7 +239,7 @@ void App::run()
                     if (make_gray) cvtColor(img_to_show, img, COLOR_GRAY2BGR);
                     else cvtColor(img_to_show, img, COLOR_BGRA2BGR);
 
-                    video_writer << img.getMat(ACCESS_READ);
+                    video_writer << img;
                 }
             }