DeviceMonitor

Added in version 1.4.

class DeviceMonitor(**properties: Any)

Superclasses: Object, InitiallyUnowned, Object

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;
}

Constructors

class DeviceMonitor

classmethod new() → DeviceMonitor: Create a new DeviceMonitor

Added in version 1.4.

Methods

class DeviceMonitor

add_filter(classes: str | None = None, caps: Caps | None = None) → int

Adds a filter for which Device will be monitored, any device that matches all these classes and the Caps will be returned.

If this function is called multiple times to add more filters, each will be matched independently. That is, adding more filters will not further restrict what devices are matched.

The Caps supported by the device as returned by get_caps() are not intersected with caps filters added using this function.

Filters must be added before the DeviceMonitor is started.

Added in version 1.4.

Parameters:

classes – device classes to use as filter or None for any class
caps – the Caps to filter or None for ANY

get_bus() → Bus: Gets the Bus of this DeviceMonitor

Added in version 1.4.

get_devices() → list[Device] | None: Gets a list of devices from all of the relevant monitors. This may actually probe the hardware if the monitor is not currently started.

Added in version 1.4.

get_providers() → list[str]

Get a list of the currently selected device provider factories.

This

Added in version 1.6.

get_show_all_devices() → bool: Get if monitor is currently showing all devices, even those from hidden providers.

Added in version 1.6.

remove_filter(filter_id: int) → bool

Removes a filter from the DeviceMonitor using the id that was returned by add_filter().

Added in version 1.4.

Parameters:: filter_id – the id of the filter

set_show_all_devices(show_all: bool) → None

Set if all devices should be visible, even those devices from hidden providers. Setting show_all to true might show some devices multiple times.

Added in version 1.6.

Parameters:: show_all – show all devices

start() → bool: Starts monitoring the devices, one this has succeeded, the DEVICE_ADDED and DEVICE_REMOVED messages will be emitted on the bus when the list of devices changes.

Added in version 1.4.

stop() → None: Stops monitoring the devices.

Added in version 1.4.

Properties

class DeviceMonitor

props.show_all: bool

Fields

class DeviceMonitor

parent: The parent Object structure

priv