    // The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
    /*

        This is an example that illustrates how to use the ffmpeg wrappers
        for taking screen grabs and plotting to a GUI window.
    */

    #include <cstdio>
    #include <dlib/media.h>
    #include <dlib/gui_widgets.h>

    using namespace std;
    using namespace dlib;

    int main()
    try
    {
        const auto demuxers              = ffmpeg::list_demuxers();
        const bool screen_grab_available = std::find(begin(demuxers), end(demuxers), "x11grab") != demuxers.end();

        if (screen_grab_available)
        {
            ffmpeg::demuxer::args args;
            args.filepath       = "";
            args.input_format   = "x11grab";

            ffmpeg::demuxer cap(args);
            if (!cap.is_open() || !cap.video_enabled())
            {
                printf("Failed to open demuxer for screen grab\n");
                return EXIT_FAILURE;
            }

            image_window win;

            ffmpeg::frame frame;
            array2d<rgb_pixel> img;

            while (cap.read(frame))
            {
                convert(frame, img);
                win.set_image(img);
            }
        }
        else
        {
            printf("Sorry your installation of ffmpeg doesn't support screen grab\n");
        }

        return EXIT_SUCCESS;
    }
    catch (const std::exception& e)
    {
        printf("%s\n", e.what());
        return EXIT_FAILURE;
    }