TX1: Accessing on-board camera stream in C++/Python

Autonomous Machines Jetson & Embedded Systems Jetson TX1
1

Hello,

I read on the forums that gstreamer can be used to access the on-board camera stream
Is there some code/guideline available on how to access the camera feed and get frames for processing?
However I am facing errors while trying to do it in C++ and OpenCV2.4.11 that I compiled from source.

here is the error,

ubuntu@tegra-ubuntu:~/code/camera$ ./bin

(bin:16258): GStreamer-WARNING **: 0.10-style raw video caps are being created. Should be video/x-raw,format=(string).. now.
0123
Available Sensor modes : 
2592 x 1944 FR=30.000000 CF=0x10d9208a isAohdr=0
2592 x 1458 FR=30.000000 CF=0x10d9208a isAohdr=0
1280 x 720 FR=120.000000 CF=0x10d9208a isAohdr=0
2592 x 1944 FR=24.000000 CF=0x10d9208a isAohdr=1

NvCameraSrc: Trying To Set Default Camera Resolution. Selected 640x480 FrameRate = 30.000000 ...

GStreamer Plugin: Embedded video playback halted; module nvcamerasrc0 reported: Internal data flow error.
OpenCV Error: Unspecified error (GStreamer: unable to start pipeline
) in icvStartPipeline, file /home/ubuntu/opencv-2.4.11/modules/highgui/src/cap_gstreamer.cpp, line 383
terminate called after throwing an instance of 'cv::Exception'
  what():  /home/ubuntu/opencv-2.4.11/modules/highgui/src/cap_gstreamer.cpp:383: error: (-2) GStreamer: unable to start pipeline
 in function icvStartPipeline

Aborted
ubuntu@tegra-ubuntu:~/code/camera$

For the following code:

//using g++ opencv.cpp `pkg-config --cflags --libs opencv`
#include "opencv2/opencv.hpp"
#include <iostream>

using namespace std;
using namespace cv;

int main(int, char**)
{

    VideoCapture cap("nvcamerasrc ! 'video/x-raw, format=(string)RGB, width=(int)640, height=(int)480 ! ffmpegcolorspace ! video/x-raw-rgb ! appsink");
    
    const char* env = "GST_DEBUG=*:3";
    putenv((char*)env);
    cout<< "0";


    cout<< "1";
    if(!cap.isOpened())
    {
        cout << "cant open camera" << endl;
        return -1;
    }
        cout<<"2";

    Mat frame;
    for(;;)
    {
        cout <<"3";
        cap >> frame; // get a new frame from camera
        cout << "4";
        imwrite("1.png", frame); 
        cout<< "5";
}
    return 0;
}

Is there some code/guideline available on how to access the camera feed and get frames for processing?

Regards,
Ankit