Question

I’m trying to play a video using opencv (the video is an avi file stored on the disk). However, the program stops execution on the following line in cap_ffmppeg.cpp:

if(!ffmpegCapture ||
   !icvRetrieveFrame_FFMPEG_p(ffmpegCapture,&data,&step,&width,&height,&cn))
   return 0;

The error is: Access violation reading location… so a seg fault is occurring the first time capture >> frame is run.

Here is the program:

#include<iostream>
#include<fstream>
#include<cv.h>
#include<highgui.h>
#include<opencv2/nonfree/features2d.hpp>
using namespace std;
using namespace cv;


int main(int argc, char *argv[])
{
    if (argc <= 1)
    {
        printf("Usage: %s video\n", argv[0]);
        return -1;
    }

    VideoCapture capture(argv[1]);


    if(!capture.isOpened())
    {
        printf("Failed to open the video\n");
        return -1;
    }

    for(;;)
    {
        Mat frame;
        capture >> frame; // get a new frame from camera
    }

    return 0;
}

Any idea what I’m doing wrong?

Answer 1

Turned out that OpenCV couldn’t play the uncompressed video. Compressed it and all is well… don’t know why the original problem exists tho.