videocapture error opening file

edit

dear, it just did not find your videofile (wrong path , probably).

the message above is just the place in the code, where the exception occurred.

the video file is in the project folder, where should i put it?

leave it there, instead look at the debugging settings of your project, and change the workingdir, so it starts from the same folder.

Or just skip placing files relatively to your executable at all and just pass along the abosute path to the file! Relative paths are the pitfall of every starting programmer.

not work, what to do?

the code is the next:

VideoCapture cap("video.avi"); // open the video file for reading

if ( !cap.isOpened() )  // if not success, exit program
{
     cout << "Cannot open the video file" << endl;
     return -1;
}

to others the code works

Change "video.avi" to the exact location, for example "/home/usr/data/video.avi" ...