Modifying pedestrian demo code to accept usb webcam as input

[R__A]

Hi

I am working on pedestrian demo code. It accepts a video file as input. How can I modify it open the webcam and start using it? 

std::unique_ptr<ImageReader> video = ImageReader::CreateImageReaderForPath(video_path);

Thanks

[R__A]

Hi

I have been able to modify the code to accept the live camera feed as input instead of a video file. I basically modified below lines:

// Opening video
	//std::unique_ptr<ImageReader> video = ImageReader::CreateImageReaderForPath(video_path);
	//cv::Mat video = cv::imread("cam", cv::IMREAD_COLOR);
	//cv::VideoCapture cap(1);
	
	//PT_CHECK(video->IsOpened()) << "failed to open video: " << video_path;

	//double video_fps = video->GetFrameRate();
	double video_fps = 29.5634;
	//if (first_frame > 0) video->SetFrameIndex(first_frame);
	//if (should_show)
	//{
		//std::cout << "To close the application, press 'CTRL+C' or any key with focus on the output window" << std::endl;
	//}
	int frame_idx = 0;
	for (;;)
	{
		//auto pair = video->Read();
		//cv::Mat frame = pair.first;
		//int frame_idx = pair.second;
		cv::VideoCapture cap;
		cap.open(0);
		cv::Mat frame;
		cap.read(frame);
		if (frame.empty())
			break;
		frame_idx = frame_idx + 1;
		/*
		PT_CHECK(frame_idx >= first_frame);

		if ((last_frame >= 0) && (frame_idx > last_frame)) {
			std::cout << "Frame " << frame_idx << " is greater than last_frame = "
				<< last_frame << " -- break";
			break;
		}*/

This build successfully with no errors. When I run the project, I was able to open the camera but terminal kept on showing below error:

InferenceEngine:
        API version ............ 1.6
        Build .................. 23224
Loading plugin CPU

        API version ............ 1.6
        Build .................. 23224
        Description ....... MKLDNNPlugin
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback
[ WARN:0] terminating async callback

Also the webcam was also turning on and then going off continuously. What does this means and how can I resolve this issue.? Thanks 

[Shubha_R_Intel]

Dear R, A,

Why not study the smart classroom demo which uses webcam by default ?

The smart classroom demo uses ImageGrabber to accomplish what you want. video_path is determined from the -i passed in by the user, which ultimately gets stored in FLAGS_i.

log::info << "Reading video '" << video_path << "'" << slog::endl;
        ImageGrabber cap(video_path);
        if (!cap.IsOpened()) {
            slog::err << "Cannot open the video" << slog::endl;
            return 1;
        }

Hope it helps. Thanks for using OpenVino !

Shubha