DeviceMonitor

Applications should create a #GstDeviceMonitor when they want to probe, list and monitor devices of a specific type. The #GstDeviceMonitor will create the appropriate #GstDeviceProvider objects and manage them. It will then post messages on its #GstBus 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;
}

class DeviceMonitor : ObjectGst {

this();

uint addFilter(string classes, gst.caps.Caps caps);

gst.bus.Bus getBus();

gst.device.Device[] getDevices();

string[] getProviders();

bool getShowAllDevices();

bool removeFilter(uint filterId);

void setShowAllDevices(bool showAll);

bool start();

void stop();

}

Constructors

this this(): Create a new #GstDeviceMonitor

Members

Functions

addFilter uint addFilter(string classes, gst.caps.Caps caps): Adds a filter for which #GstDevice will be monitored, any device that matches all these classes and the #GstCaps will be returned.
getBus gst.bus.Bus getBus(): Gets the #GstBus of this #GstDeviceMonitor
getDevices gst.device.Device[] getDevices(): Gets a list of devices from all of the relevant monitors. This may actually probe the hardware if the monitor is not currently started.
getProviders string[] getProviders(): Get a list of the currently selected device provider factories.
getShowAllDevices bool getShowAllDevices(): Get if monitor is currently showing all devices, even those from hidden providers.
removeFilter bool removeFilter(uint filterId): Removes a filter from the #GstDeviceMonitor using the id that was returned by gst.device_monitor.DeviceMonitor.addFilter.
setShowAllDevices void setShowAllDevices(bool showAll): Set if all devices should be visible, even those devices from hidden providers. Setting show_all to true might show some devices multiple times.
start bool start(): Starts monitoring the devices, one this has succeeded, the gst.types.MessageType.DeviceAdded and gst.types.MessageType.DeviceRemoved messages will be emitted on the bus when the list of devices changes.
stop void stop(): Stops monitoring the devices.

Inherited Members

From ObjectGst

checkUniqueness bool checkUniqueness(gst.object.ObjectGst[] list, string name): Checks to see if there is any object named name in list. This function does not do any locking of any kind. You might want to protect the provided list with the lock of the owner of the list. This function will lock each #GstObject in the list to compare the name, so be careful when passing a list with a locked object.
defaultDeepNotify void defaultDeepNotify(gobject.object.ObjectG object, gst.object.ObjectGst orig, gobject.param_spec.ParamSpec pspec, string[] excludedProps): A default deep_notify signal callback for an object. The user data should contain a pointer to an array of strings that should be excluded from the notify. The default handler will print the new value of the property using g_print.
replace bool replace(gst.object.ObjectGst oldobj, gst.object.ObjectGst newobj): Atomically modifies a pointer to point to a new object. The reference count of oldobj is decreased and the reference count of newobj is increased.
addControlBinding bool addControlBinding(gst.control_binding.ControlBinding binding): Attach the #GstControlBinding to the object. If there already was a #GstControlBinding for this property it will be replaced.
defaultError void defaultError(glib.error.ErrorG error, string debug_): A default error function that uses glib.global.printerr to display the error message and the optional debug string..
getControlBinding gst.control_binding.ControlBinding getControlBinding(string propertyName): Gets the corresponding #GstControlBinding for the property. This should be unreferenced again after use.
getControlRate gst.types.ClockTime getControlRate(): Obtain the control-rate for this object. Audio processing #GstElement objects will use this rate to sub-divide their processing loop and call gst.object.ObjectGst.syncValues in between. The length of the processing segment should be up to control-rate nanoseconds.
getGValueArray bool getGValueArray(string propertyName, gst.types.ClockTime timestamp, gst.types.ClockTime interval, gobject.value.Value[] values): Gets a number of #GValues for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of #GValue.
getName string getName(): Returns a copy of the name of object. Caller should glib.global.gfree the return value after usage. For a nameless object, this returns null, which you can safely glib.global.gfree as well.
getParent gst.object.ObjectGst getParent(): Returns the parent of object. This function increases the refcount of the parent object so you should gst.object.ObjectGst.unref it after usage.
getPathString string getPathString(): Generates a string describing the path of object in the object hierarchy. Only useful (or used) for debugging.
getValue gobject.value.Value getValue(string propertyName, gst.types.ClockTime timestamp): Gets the value for the given controlled property at the requested time.
hasActiveControlBindings bool hasActiveControlBindings(): Check if the object has active controlled properties.
hasAncestor bool hasAncestor(gst.object.ObjectGst ancestor): Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a #GstElement is inside a #GstPipeline.
hasAsAncestor bool hasAsAncestor(gst.object.ObjectGst ancestor): Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a #GstElement is inside a #GstPipeline.
hasAsParent bool hasAsParent(gst.object.ObjectGst parent): Check if parent is the parent of object. E.g. a #GstElement can check if it owns a given #GstPad.
removeControlBinding bool removeControlBinding(gst.control_binding.ControlBinding binding): Removes the corresponding #GstControlBinding. If it was the last ref of the binding, it will be disposed.
setControlBindingDisabled void setControlBindingDisabled(string propertyName, bool disabled): This function is used to disable the control bindings on a property for some time, i.e. gst.object.ObjectGst.syncValues will do nothing for the property.
setControlBindingsDisabled void setControlBindingsDisabled(bool disabled): This function is used to disable all controlled properties of the object for some time, i.e. gst.object.ObjectGst.syncValues will do nothing.
setControlRate void setControlRate(gst.types.ClockTime controlRate): Change the control-rate for this object. Audio processing #GstElement objects will use this rate to sub-divide their processing loop and call gst.object.ObjectGst.syncValues in between. The length of the processing segment should be up to control-rate nanoseconds.
setName bool setName(string name): Sets the name of object, or gives object a guaranteed unique name (if name is null). This function makes a copy of the provided name, so the caller retains ownership of the name it sent.
setParent bool setParent(gst.object.ObjectGst parent): Sets the parent of object to parent. The object's reference count will be incremented, and any floating reference will be removed (see gst.object.ObjectGst.refSink).
suggestNextSync gst.types.ClockTime suggestNextSync(): Returns a suggestion for timestamps where buffers should be split to get best controller results.
syncValues bool syncValues(gst.types.ClockTime timestamp): Sets the properties of the object, according to the #GstControlSources that (maybe) handle them and for the given timestamp.
unparent void unparent(): Clear the parent of object, removing the associated reference. This function decreases the refcount of object.
connectDeepNotify ulong connectDeepNotify(string detail, T callback, Flag!"After" after): Connect to DeepNotify signal.

gst device_monitor classes

DeviceMonitor