Sowmya Shree's profile - activity

C4146 unary minus operator is applied to unsigned type, result still unsigned error encountered in opencv visual studio

C4146 unary minus operator is applied to unsigned type, result still unsigned error encountered in opencv visual studio

Here is my new code.

int main(void) {

cv::VideoCapture capVideo;

cv::Mat imgFrame;

capVideo.open("C:\Users\sbv\Documents\MyVideo.avi");

if (!capVideo.isOpened()) {
std::cout << "\nerror reading video file" << std::endl << std::endl;
_getch();
return(0); }

if (capVideo.get(CV_CAP_PROP_FRAME_COUNT) < 1) { std::cout << "\nerror: video file must have at least one frame"; _getch(); return(0); }

capVideo.read(imgFrame);

char chCheckForEscKey = 0;

while (capVideo.isOpened() && chCheckForEscKey != 27) {

cv::imshow("imgFrame", imgFrame);

if ((capVideo.get(CV_CAP_PROP_POS_FRAMES) + 1) < capVideo.get(CV_CAP_PROP_FRAME_COUNT)) 
        {
        capVideo.read(imgFrame);                          
}
else 
        {
         std::cout << "end of video\n";
         break;                                              
}

chCheckForEscKey = cv::waitKey(1);      
    }

if (chCheckForEscKey != 27) {
cv::waitKey(0);
} return(0);

}

error is coming as 'Error reading video file'. please solve this issue

Please tell me how a video file is played in Opencv. I tried using cvCapture. here is the following code I used. it is displaying 'video not opened'.

int main(int argc, char* argv[]) { CvCapture* capture = cvCreateFileCapture("C:\Users\sbv\Documents\MyVideo.avi");

IplImage* frame = NULL;

if (!capture)
{
    printf("Video Not Opened\n");
    return -1;
}

int width = (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH);
int height = (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT);
double fps = cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
int frame_count = (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_COUNT);

printf("Video Size = %d x %d\n", width, height);
printf("FPS = %f\nTotal Frames = %d\n", fps, frame_count);

while (1)
{
    frame = cvQueryFrame(capture);

    if (!frame)
    {
        printf("Capture Finished\n");
        break;
    }

    cvShowImage("video", frame);
    cvWaitKey(10);
}

cvReleaseCapture(&capture);
return 0;

}

Image read is working properly. but while writing an image in a particular location such as C or D drive. Error is 'failed to write image'. same issue for video read and write also. please help me to solve this issue.

Image write program

#include<opencv2/highgui/highgui.hpp>
#include<opencv2/core/core.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, const char** argv)
{
    Mat img(650, 600, CV_16UC3, Scalar(0, 50000, 50000)); 

    if (img.empty()) 
    {
        cout << "ERROR : Image cannot be loaded..!!" << endl;
        system("pause"); 
        return -1;
    }


    vector<int> compression_params; 

    compression_params.push_back(CV_IMWRITE_JPEG_QUALITY); 

    compression_params.push_back(98); 

    bool bSuccess = imwrite("C:\\Users\\sbv\\Documnents\\TestImage.jpg", img, compression_params); 

    if (!bSuccess)
    {

        cout << "ERROR : Failed to save the image" << endl;
        system("pause"); 

    }

    namedWindow("MyWindow", CV_WINDOW_AUTOSIZE); 
    imshow("MyWindow", img); 

    waitKey(0);  

    destroyWindow("MyWindow"); 

    return 0;
}


**Video write program**
#include<opencv2/core/core.hpp>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char* argv[])
{
    VideoCapture cap(0); 

    //VideoCapture cap("C:\\Users\\sbv\\Documents\\video.mp4");

    if (!cap.isOpened())  
    {
        cout << "ERROR: Cannot open the video file" << endl;
        return -1;
    }

    namedWindow("MyVideo", CV_WINDOW_AUTOSIZE); 

    double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH); 
    double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT); 

    cout << "Frame Size = " << dWidth << "x" << dHeight << endl;

    Size frameSize(static_cast<int>(dWidth), static_cast<int>(dHeight));

    VideoWriter VideoWriter("C:/MyVideo.avi", CV_FOURCC('P', 'I', 'M', '1'), 20, frameSize, true); 

    if (!VideoWriter.isOpened()) 
    {
        cout << "ERROR: Failed to write the video" << endl;
        return -1;
    }

    while (1)
    {

        Mat frame;

        bool bSuccess = cap.read(frame); 

        if (!bSuccess) 
        {
            cout << "ERROR: Cannot read a frame from video file" << endl;
            break;
        }

        VideoWriter.write(frame); 

        imshow("MyVideo", frame); 

        if (waitKey(10) == 27) 
        {
            cout << "esc key is pressed by user" << endl;
            break;
        }
    }

    return 0;

}

I am using Opencv for my project and for the first time. While using Opencv I faced problem as “Opencv_world330d.dll is missing” message is displayed as soon as I run the program. I also added "OpenCV-world330d.lib" in Properties => linker => input=>additional dependency. I couldn't able to solve this problem. Please help me to solve this issue.

Opencv_world330d.dll is present in the folder.

It is working. Thanks @Balaji R