device-provider.c

#include <gst/gst.h>
#include <stdio.h>
#include <string.h>

static gboolean
my_bus_func (GstBus * bus, GstMessage * message, gpointer user_data)
{
    GstDevice *device;
    gchar *name;

    switch (GST_MESSAGE_TYPE (message)) {
    case GST_MESSAGE_DEVICE_ADDED:
        gst_message_parse_device_added (message, &device);
        name = gst_device_get_display_name (device);
        g_print("Device added: %s\n", name);
        g_free (name);
        gst_object_unref (device);
        break;
    case GST_MESSAGE_DEVICE_REMOVED:
        gst_message_parse_device_removed (message, &device);
        name = gst_device_get_display_name (device);
        g_print("Device removed: %s\n", name);
        g_free (name);
        gst_object_unref (device);
        break;
    default:
        break;
    }

    return G_SOURCE_CONTINUE;
}

int main()
{
    GstDeviceMonitor *monitor;
    GstBus *bus;
    GstCaps *caps;

    monitor = gst_device_monitor_new();
    bus = gst_device_monitor_get_bus (monitor);
    gst_bus_add_watch (bus, my_bus_func, NULL);
    gst_object_unref(bus);

    caps = gst_caps_new_empty_simple ("video/x-raw");
    gst_device_monitor_add_filter (monitor, "Video/Source", caps);
    gst_caps_unref (caps);

    if(gst_device_monitor_start(monitor))
        printf("Monitor started\n");
    else
        printf("Monitor failed to start\n");
        return 0;

    g_autofree GList *devices = gst_device_monitor_get_devices(monitor);

    for (int i = 0; i < g_list_length(devices); i++)
    {
        GstDevice *device = g_list_nth_data(devices, i);
        printf("device: %s", gst_device_get_display_name(device));
    }

    gst_device_monitor_stop(monitor);

    return 0;
}