People counting not working

I have down loaded program from https://github.com/saimj7/People-Counting-in-Real-Time. Following observation and looking for solution to problem…
Video streaming working fine. nvcc --version responded fine.
People-counting working fine with demo video.
Not starting video streaming getting following error.
[INFO] Starting the live stream…
[ WARN:0] global /home/nvidia/host/build_opencv/nv_opencv/modules/videoio/src/cap_gstreamer.cpp (1757) handleMessage OpenCV | GStreamer warning: Embedded video playback halted; module v4l2src0 reported: Internal data stream error.
[ WARN:0] global /home/nvidia/host/build_opencv/nv_opencv/modules/videoio/src/cap_gstreamer.cpp (886) open OpenCV | GStreamer warning: unable to start pipeline
[ WARN:0] global /home/nvidia/host/build_opencv/nv_opencv/modules/videoio/src/cap_gstreamer.cpp (480) isPipelinePlaying OpenCV | GStreamer warning: GStreamer: pipeline have not been created

Both cap_gstreamer.cpp and cap.cpp file copied in created folder file path --/home/nvidia/host/build_opencv/nv_opencv/modules/videoio/src/ . Please help/inform, how to make use of it and make it working.