DeviceMonitor

Applications should create a DeviceMonitor when they want to probe, list and monitor devices of a specific type.

The DeviceMonitor will create the appropriate DeviceProvider objects and manage them. It will then post messages on its Bus for devices that have been added and removed.

The device monitor will monitor all devices matching the filters that the application has set.

The basic use pattern of a device monitor is as follows:

  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;
  }

  GstDeviceMonitor *
  setup_raw_video_source_device_monitor (void) {
     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);

     gst_device_monitor_start (monitor);

     return monitor;
  }