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c++opencvvideo-capture

cvQueryFrame(capture) always returns null

Does anyone know why I keep getting null frames? I tried skipping the first five and still null. 

int _tmain(int argc, char** argv)
{
CvCapture *capture  = cvCaptureFromFile(argv[1]);

int fps = (int)cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
IplImage* frame;
cvNamedWindow("video", CV_WINDOW_AUTOSIZE);
while(1)
{
    frame = cvQueryFrame(capture);
    if(!frame)
        break;
    cvShowImage("video", frame);
    char c = cvWaitKey(1000/fps);
    if(c == 33)
        break;
}
cvReleaseCapture( &capture);
cvDestroyWindow( "video" );

return 0;
}
Solution

  • Video file must UNCOMPRESSED avi! So actually I was getting null frames because cvCapture returned a null because my input video file was not uncompressed.