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.

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class DeviceMonitor : ObjectGst {

protected

GstDeviceMonitor* gstDeviceMonitor;

GstDeviceMonitor* getDeviceMonitorStruct();

void* getStruct();

void setStruct(GObject* obj);

this(GstDeviceMonitor* gstDeviceMonitor, bool ownedRef);

static GType getType();

this();

uint addFilter(string classes, Caps caps);

Bus getBus();

ListG getDevices();

bool removeFilter(uint filterId);

bool start();

void stop();

}

Constructors

this this(GstDeviceMonitor* gstDeviceMonitor, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(): Create a new #GstDeviceMonitor

Members

Functions

addFilter uint addFilter(string classes, Caps caps): Adds a filter for which #GstDevice will be monitored, any device that matches all classes and the #GstCaps will be returned.
getBus Bus getBus(): Gets the #GstBus of this #GstDeviceMonitor
getDeviceMonitorStruct GstDeviceMonitor* getDeviceMonitorStruct(): Get the main Gtk struct
getDevices ListG 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.
getStruct void* getStruct(): the main Gtk struct as a void*
removeFilter bool removeFilter(uint filterId): Removes a filter from the #GstDeviceMonitor using the id that was returned by gst_device_monitor_add_filter().
setStruct void setStruct(GObject* obj): Undocumented in source. Be warned that the author may not have intended to support it.
start bool start(): Starts monitoring the devices, one this has succeeded, the %GST_MESSAGE_DEVICE_ADDED and %GST_MESSAGE_DEVICE_REMOVED messages will be emitted on the bus when the list of devices changes.
stop void stop(): Stops monitoring the devices.

Static functions

getType GType getType()

Variables

gstDeviceMonitor GstDeviceMonitor* gstDeviceMonitor;: the main Gtk struct

Inherited Members

From ObjectGst

gstObject GstObject* gstObject;: the main Gtk struct
getObjectGstStruct GstObject* getObjectGstStruct(): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
setStruct void setStruct(GObject* obj): Undocumented in source. Be warned that the author may not have intended to support it.
getType GType getType()
checkUniqueness bool checkUniqueness(ListG 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(ObjectG object, ObjectGst orig, 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.
refSink void* refSink(void* object): Increase the reference count of @object, and possibly remove the floating reference, if @object has a floating reference.
replace bool replace(ObjectGst oldobj, 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(ControlBinding binding): Attach the #GstControlBinding to the object. If there already was a #GstControlBinding for this property it will be replaced.
defaultError void defaultError(ErrorG error, string dbg): A default error function that uses g_printerr() to display the error message and the optional debug sting..
getControlBinding ControlBinding getControlBinding(string propertyName): Gets the corresponding #GstControlBinding for the property. This should be unreferenced again after use.
getControlRate GstClockTime 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_sync_values() inbetween. The length of the processing segment should be up to @control-rate nanoseconds.
getGValueArray bool getGValueArray(string propertyName, GstClockTime timestamp, GstClockTime interval, uint nValues, 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 g_free() the return value after usage. For a nameless object, this returns %NULL, which you can safely g_free() as well.
getParent ObjectGst getParent(): Returns the parent of @object. This function increases the refcount of the parent object so you should gst_object_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 Value getValue(string propertyName, GstClockTime timestamp): Gets the value for the given controlled property at the requested time.
getValueArray bool getValueArray(string propertyName, GstClockTime timestamp, GstClockTime interval, uint nValues, void* values): Gets a number of values for the given controlled property starting at the requested time. The array @values need to hold enough space for @n_values of the same type as the objects property's type.
hasActiveControlBindings bool hasActiveControlBindings(): Check if the @object has an active controlled properties.
hasAncestor bool hasAncestor(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.
doref ObjectGst doref(): Increments the reference count on @object. This function does not take the lock on @object because it relies on atomic refcounting.
removeControlBinding bool removeControlBinding(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_sync_values() 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_sync_values() will do nothing.
setControlRate void setControlRate(GstClockTime 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_sync_values() inbetween. 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(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_ref_sink()).
suggestNextSync GstClockTime suggestNextSync(): Returns a suggestion for timestamps where buffers should be split to get best controller results.
syncValues bool syncValues(GstClockTime 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.
unref void unref(): Decrements the reference count on @object. If reference count hits zero, destroy @object. This function does not take the lock on @object as it relies on atomic refcounting.
connectedSignals int[string] connectedSignals;: Undocumented in source.
onDeepNotifyListeners void delegate(ObjectGst, ParamSpec, ObjectGst)[] onDeepNotifyListeners;: Undocumented in source.
addOnDeepNotify void addOnDeepNotify(void delegate(ObjectGst, ParamSpec, ObjectGst) dlg, ConnectFlags connectFlags): The deep notify signal is used to be notified of property changes. It is typically attached to the toplevel bin to receive notifications from all the elements contained in that bin.
callBackDeepNotify void callBackDeepNotify(GstObject* objectgstStruct, GstObject* propObject, GParamSpec* prop, ObjectGst _objectgst): Undocumented in source. Be warned that the author may not have intended to support it.

Detailed Description

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); 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); 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; } ]|