Opening GoPro with AverMedia ExtremeCap UVC, e-cons , and on board camera on Jetson TX2

JetsonCamera.cpp

/*
Terminal gstreamer pipeline

GoPro - UVC
gst-launch-1.0 v4l2src device="/dev/video1" ! "video/x-raw,width=1920,height=1080,format=YUY2" ! nvvidconv ! 'video/x-raw(memory:NVMM),format=NV12' ! nvvidconv ! xvimagesink

E-cons camera
gst-launch-1.0 v4l2src device="/dev/video1" ! "video/x-raw,width=1920,height=1080,format=UYVY" ! nvvidconv ! 'video/x-raw(memory:NVMM),format=NV12' ! nvoverlaysink

Jetson on board camera
gst-launch-1.0 nvarguscamerasrc sensor-id=0 ! 'video/x-raw(memory:NVMM),width=1920, height=1080, framerate=30/1, format=NV12' ! nvoverlaysink -ev
*/

#include "opencv2/opencv.hpp"
#include <opencv2/highgui.hpp>
#include <iostream>
 
using namespace std;
using namespace cv;
 
int main(int argc, char *argv[]){
 
  // Create a VideoCapture object and open the input file
  // If the input is the web camera, pass 0 instead of the video file name
  string gst;
  string idx = argv[1];  
  string cam = argv[2];
  
  //GoPro UVC Camera format=YUY2
  if (cam == "1")
    gst =  "v4l2src device=/dev/video"+idx+" ! video/x-raw, width=(int)1920, height=(int)1080, format=(string)YUY2 ! videoconvert ! appsink";
  //E-Con Camera format=UYVY
  else if (cam == "2")
    gst =  "v4l2src device=/dev/video"+idx+" ! video/x-raw, width=(int)1920, height=(int)1080, format=(string)UYVY ! videoconvert ! appsink";
  //Jetson On board Camera format = nvarguscamerasrc (nvcamerasrc is deprecated in Jetpack 4.2)
  else if (cam == "3")
    gst = "nvarguscamerasrc ! video/x-raw(memory:NVMM), width=(int)1280, height=(int)720,format=(string)NV12, framerate=(fraction)24/1 ! nvvidconv ! video/x-raw, format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink";

  VideoCapture cap(gst); //Choose gst pipeline
    
  if(!cap.isOpened()){
    cout << "Error opening video stream or file" << endl;
    return -1;
  }
     
  while(1){
 
    Mat frame;
    cap >> frame;
  
    if (frame.empty())
      break;

    imshow( "Frame", frame );
 
    char c=(char)waitKey(25);
    if(c==27)
      break;
  }
  
  cap.release();
 
  destroyAllWindows();
     
  return 0;
}