using videoinput from OpenCv - c++

Question

I’m looking for a simple way to use videoinput from OpenCv, because I read a lot of material from the net but still I’m very confused.
I’ve read that from release 2.3 it is part of OpenCv.
What does it mean?
I included “highgui.hpp” and declared “videoInput VI” (with HAVE_DSHOW
HAVE_VIDEOINPUT defined), but got error 'videoInput' not identified.
Then I included a "videoinput.h" file I found in the web and I got
“error LNK2001: simbolo esterno "public: __thiscall videoInput::~videoInput(void)" (??1videoInput##QAE#XZ) non risolto”
Have I to download libraries as well?
I thought it should be simpler given that it is “part of OpenCv”.

Answer 1

If you want to read and process the video frames I recommend you the VideoCapture class.
Here is an example with an edge detector:
#include "opencv2/opencv.hpp"
using namespace cv;
int main(int, char**)
{
VideoCapture cap("videofilename"); // open the video file
if(!cap.isOpened()) // check if we succeeded
return -1;
Mat edges;
namedWindow("edges",1);
for(;;)
{
Mat frame;
cap >> frame; // get a new frame from the video
cvtColor(frame, edges, CV_BGR2GRAY);
GaussianBlur(edges, edges, Size(7,7), 1.5, 1.5);
Canny(edges, edges, 0, 30, 3);
imshow("edges", edges);
if(waitKey(30) >= 0) break;
}
return 0;
}