how to caputre video from usb camera in MJPEG pixel format - c++

Question

i working in stereo cameras project (connect two usb cameras to my laptop) but the proplem is my web cameras format are "YUYV" and this format did't support that to run two cameras togther so how i do that ? that's my code in c++ and opencv3
#include <opencv2/opencv.hpp>
/**
* #file main.cpp
* #brief OpenCV Stereo Webcam.
* #author Martin Peris (http://www.martinperis.com)
* #date 21/08/2011
*/
/*
main.cpp - Implement a simple stereo webcam with OpenCV and C++
Copyright (c) 2011 Martin Peris (http://www.martinperis.com).
All right reserved.
This application is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This application is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this application; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
//This works for me on OpenCV 2.0 with 2 Logicool webcams.
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <vector>
#include <iostream>
#include <sstream>
#include <opencv2/video/background_segm.hpp>
#include <opencv2/video/background_segm.hpp>
#include "cv.h"
#include "highgui.h"
#include <iostream>
//Maybe in OpenCV2.2 the correct include statement would be:
//#include "opencv2/opencv.hpp"
int main(int, char**)
{
cv::VideoCapture capLeft(4); // open the Left camera
cv::VideoCapture capRight(2); // open the Right camera
if(!capLeft.isOpened() || !capRight.isOpened()) // check if we succeeded
{
std::cerr << "ERROR: Could not open cameras." << std::endl;
return -1;
}
capLeft.set(CV_CAP_PROP_FPS, 25);
capRight.set(CV_CAP_PROP_FPS, 25);
// Values taken from output of Version 1 and used to setup the exact same parameters with the exact same values!
capLeft.set(CV_CAP_PROP_FRAME_WIDTH, 320);
capLeft.set(CV_CAP_PROP_FRAME_HEIGHT, 240);
capRight.set(CV_CAP_PROP_FRAME_WIDTH, 320);
capRight.set(CV_CAP_PROP_FRAME_HEIGHT, 240);
cv::namedWindow("Left",1);
cv::namedWindow("Right",1);
for(;;)
{
bool isValid = true;
cv::Mat frameLeft;
cv::Mat frameRight;
try
{
capLeft >> frameLeft; // get a new frame from left camera
capRight >> frameRight; //get a new frame from right camera
}
catch( cv::Exception& e )
{
std::cout << "An exception occurred. Ignoring frame. " << e.err << std::endl;
isValid = false;
}
if (isValid)
{
try
{
cv::imshow("Left", frameLeft);
cv::imshow("Right", frameRight);
/************************************************************
* This is the place for all the cool stuff that you *
* want to do with your stereo images *
************************************************************/
//TODO:...
}
catch( cv::Exception& e )
{
/************************************************************
* Sometimes an "Unrecognized or unsuported array type" *
* exception is received so we handle it to avoid dying *
************************************************************/
std::cout << "An exception occurred. Ignoring frame. " << e.err << std::endl;
}
}
if(cv::waitKey(30) >= 0) break;
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;
}