c++ - Random frame of Video AR Drone is empty and then can't get a new image with OpenCV -

i'm doing simple program print ar.drone video during flight on computer.

it works during few seconds , then, randomly, program abort because frame empty. decided test it, now, when frame empty, following frames empty too.

here simple code :

int main(void) {   cv::videocapture cap;   cv::mat image;    if (!cap.open("tcp://192.168.1.1:5555"))     {       printf("ar.drone error connect\n");       return -1;     }    takeoff();    while (42)     {       cap >> image;        if (!image.empty())         {            cv::imshow("ar.drone", image);            std::cout << "ok" << std::endl;         }       else         std::cout << "error" << std::endl;       cv::waitkey(1);     }       return 0; } 

my output :

>ok >ok >[...] >ok >err >err >err 

but should :

>ok >ok >[...] >ok >err   // okay got error ? ... >ok    // ... give new frame :) >ok 

why fail forever?

if don't protect error “opencv error: bad flag” , abort. connection on ar.drone tcp, can't slow down waitkey...

any idea?

i got same issue when wanted stable video stream ar.drone 2.0 took time, realized frame missing because drone consider connection lost after 2 seconds without @ command. if open stream , nothing more fine (the stream good), after send @ command after 2 second drone disconnect. need send example hovering command drone if no other command sent keep connection alive.