Capture from device and file with HW acceleration

videoio.cpp

@@ -17,6 +17,16 @@ bool VideoCapture_OpenWithAPI(VideoCapture v, const char* uri, int apiPreference
     return v->open(uri, apiPreference);
 }
 
+bool VideoCapture_OpenWithAPIParams(VideoCapture v, const char* uri, int apiPreference, int *paramsv, int paramsc) {
+    std::vector< int > params;
+
+    for( int i = 0; i< paramsc; i++) {
+        params.push_back(paramsv[i]);
+    }
+
+    return v->open(uri, apiPreference, params);
+}
+
 bool VideoCapture_OpenDevice(VideoCapture v, int device) {
     return v->open(device);
 }
@@ -25,6 +35,17 @@ bool VideoCapture_OpenDeviceWithAPI(VideoCapture v, int device, int apiPreferenc
     return v->open(device, apiPreference);
 }
 
+bool VideoCapture_OpenDeviceWithAPIParams(VideoCapture v, int device, int apiPreference, int *paramsv, int paramsc) {
+    std::vector< int > params;
+
+    for( int i = 0; i< paramsc; i++) {
+        params.push_back(paramsv[i]);
+    }
+
+    return v->open(device, apiPreference, params);
+}
+
+
 void VideoCapture_Set(VideoCapture v, int prop, double param) {
     v->set(prop, param);
 }

videoio.go

@@ -280,6 +280,12 @@ const (
 
 	// VideoCaptureBitrate displays the video bitrate in kbits/s. Read-only property.
 	VideoCaptureBitrate VideoCaptureProperties = 47
+
+	// VideoCaptureHWAcceleration Hardware acceleration type.
+	VideoCaptureHWAcceleration VideoCaptureProperties = 50
+
+	// VideoCaptureHWDevice Hardware device index (select GPU if multiple available).
+	VideoCaptureHWDevice VideoCaptureProperties = 51
 )
 
 // VideoCapture is a wrapper around the OpenCV VideoCapture class.
@@ -320,6 +326,21 @@ func VideoCaptureFileWithAPI(uri string, apiPreference VideoCaptureAPI) (vc *Vid
 	return
 }
 
+// VideoCaptureFileWithAPIParams opens a VideoCapture from a file and prepares
+// to start capturing. It returns error if it fails to open the file stored in uri path.
+func VideoCaptureFileWithAPIParams(uri string, apiPreference VideoCaptureAPI, params []VideoCaptureProperties) (vc *VideoCapture, err error) {
+	vc = &VideoCapture{p: C.VideoCapture_New()}
+
+	cURI := C.CString(uri)
+	defer C.free(unsafe.Pointer(cURI))
+
+	if !C.VideoCapture_OpenWithAPIParams(vc.p, cURI, C.int(apiPreference), (*C.int)(unsafe.Pointer(&params[0])), C.int(len(params))) {
+		err = fmt.Errorf("Error opening file: %s with api backend: %d", uri, apiPreference)
+	}
+
+	return
+}
+
 // VideoCaptureDevice opens a VideoCapture from a device and prepares
 // to start capturing. It returns error if it fails to open the video device.
 func VideoCaptureDevice(device int) (vc *VideoCapture, err error) {
@@ -332,7 +353,7 @@ func VideoCaptureDevice(device int) (vc *VideoCapture, err error) {
 	return
 }
 
-// VideoCaptureDevice opens a VideoCapture from a device with the api preference.
+// VideoCaptureDeviceWithAPI opens a VideoCapture from a device with the api preference.
 // It returns error if it fails to open the video device.
 func VideoCaptureDeviceWithAPI(device int, apiPreference VideoCaptureAPI) (vc *VideoCapture, err error) {
 	vc = &VideoCapture{p: C.VideoCapture_New()}
@@ -344,6 +365,18 @@ func VideoCaptureDeviceWithAPI(device int, apiPreference VideoCaptureAPI) (vc *V
 	return
 }
 
+// VideoCaptureDeviceWithAPIParams opens a VideoCapture from a device with the api preference.
+// It returns error if it fails to open the video device.
+func VideoCaptureDeviceWithAPIParams(device int, apiPreference VideoCaptureAPI, params []VideoCaptureProperties) (vc *VideoCapture, err error) {
+	vc = &VideoCapture{p: C.VideoCapture_New()}
+
+	if !C.VideoCapture_OpenDeviceWithAPIParams(vc.p, C.int(device), C.int(apiPreference), (*C.int)(unsafe.Pointer(&params[0])), C.int(len(params))) {
+		err = fmt.Errorf("Error opening device: %d with api backend: %d", device, apiPreference)
+	}
+
+	return
+}
+
 // Close VideoCapture object.
 func (v *VideoCapture) Close() error {
 	C.VideoCapture_Close(v.p)
@@ -491,6 +524,9 @@ func OpenVideoCapture(v interface{}) (*VideoCapture, error) {
 	}
 }
 
+// OpenVideoCaptureWithAPI return VideoCapture specified by device ID if v is a
+// number. Return VideoCapture created from video file, URL, or GStreamer
+// pipeline if v is a string.
 func OpenVideoCaptureWithAPI(v interface{}, apiPreference VideoCaptureAPI) (*VideoCapture, error) {
 	switch vv := v.(type) {
 	case int:
@@ -505,3 +541,22 @@ func OpenVideoCaptureWithAPI(v interface{}, apiPreference VideoCaptureAPI) (*Vid
 		return nil, errors.New("argument must be int or string")
 	}
 }
+
+// OpenVideoCaptureWithAPIParams return VideoCapture specified by device ID if v is a
+// number. Return VideoCapture created from video file, URL, or GStreamer
+// pipeline if v is a string.
+func OpenVideoCaptureWithAPIParams(v interface{}, apiPreference VideoCaptureAPI, params []VideoCaptureProperties) (*VideoCapture, error) {
+	switch vv := v.(type) {
+	case int:
+		return VideoCaptureDeviceWithAPIParams(vv, apiPreference, params)
+	case string:
+		id, err := strconv.Atoi(vv)
+		if err == nil {
+			return VideoCaptureDeviceWithAPIParams(id, apiPreference, params)
+		}
+		//TODO: params with files
+		return VideoCaptureFileWithAPIParams(vv, apiPreference, params)
+	default:
+		return nil, errors.New("argument must be int or string")
+	}
+}

videoio.h

@@ -21,8 +21,10 @@ VideoCapture VideoCapture_New();
 void VideoCapture_Close(VideoCapture v);
 bool VideoCapture_Open(VideoCapture v, const char* uri);
 bool VideoCapture_OpenWithAPI(VideoCapture v, const char* uri, int apiPreference);
+bool VideoCapture_OpenWithAPIParams(VideoCapture v, const char* uri, int apiPreference, int *paramsv, int paramsc);
 bool VideoCapture_OpenDevice(VideoCapture v, int device);
 bool VideoCapture_OpenDeviceWithAPI(VideoCapture v, int device, int apiPreference);
+bool VideoCapture_OpenDeviceWithAPIParams(VideoCapture v, int device, int apiPreference, int *paramsv, int paramsc);
 void VideoCapture_Set(VideoCapture v, int prop, double param);
 double VideoCapture_Get(VideoCapture v, int prop);
 int VideoCapture_IsOpened(VideoCapture v);

videoio_test.go

@@ -97,6 +97,18 @@ func TestVideoCaptureWithAPI(t *testing.T) {
 	})
 }
 
+func TestVideoCaptureWithAPIParams(t *testing.T) {
+	vc, _ := OpenVideoCaptureWithAPIParams(0, VideoCaptureAny, []VideoCaptureProperties{VideoCaptureHWAcceleration, 1, VideoCaptureHWDevice, 0})
+	defer vc.Close()
+
+}
+
+func TestVideoCaptureFileWithAPIParams(t *testing.T) {
+	vc, _ := OpenVideoCaptureWithAPIParams("images/small.mp4", VideoCaptureAny, []VideoCaptureProperties{VideoCaptureHWAcceleration, 1, VideoCaptureHWDevice, 0})
+	defer vc.Close()
+
+}
+
 func TestVideoCaptureFile(t *testing.T) {
 	vc, err := VideoCaptureFile("images/small.mp4")
 	defer vc.Close()