GstDeviceMonitor

GstDeviceMonitor — A device monitor and prober

Functions

GstDeviceMonitor * gst_device_monitor_new ()
GstBus * gst_device_monitor_get_bus ()
guint gst_device_monitor_add_filter ()
gboolean gst_device_monitor_remove_filter ()
gboolean gst_device_monitor_start ()
void gst_device_monitor_stop ()
GList * gst_device_monitor_get_devices ()

Types and Values

struct GstDeviceMonitor
struct GstDeviceMonitorClass

Object Hierarchy







Includes


#include <gst/gst.h>







Description


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:



  

    
      

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

   gst_device_monitor_start (monitor);

   return monitor;
}

      

    
  











Functions




gst_device_monitor_new ()


GstDeviceMonitor *
gst_device_monitor_new (void);


Create a new GstDeviceMonitor




Returns


 a new device monitor. 


[transfer full]




Since 1.4








gst_device_monitor_get_bus ()


GstBus *
gst_device_monitor_get_bus (GstDeviceMonitor *monitor);


Gets the GstBus of this GstDeviceMonitor




Parameters











monitor


a GstDeviceProvider

 









Returns


 a GstBus. 


[transfer full]




Since 1.4








gst_device_monitor_add_filter ()


guint
gst_device_monitor_add_filter (GstDeviceMonitor *monitor,
                               const gchar *classes,
                               GstCaps *caps);


Adds a filter for which GstDevice will be monitored, any device that matches
all classes and the GstCaps will be returned.


Filters must be added before the GstDeviceMonitor is started.




Parameters












monitor


a device monitor

 





classes


 device classes to use as filter or NULL for any class. 

[allow-none]





caps


 the GstCaps to filter or NULL for ANY. 

[allow-none]










Returns


 The id of the new filter or 0 if no provider matched the filter's
classes.






Since 1.4








gst_device_monitor_remove_filter ()


gboolean
gst_device_monitor_remove_filter (GstDeviceMonitor *monitor,
                                  guint filter_id);


Removes a filter from the GstDeviceMonitor using the id that was returned
by gst_device_monitor_add_filter().




Parameters












monitor


a device monitor

 





filter_id


the id of the filter

 










Returns


 TRUE of the filter id was valid, FALSE otherwise






Since 1.4








gst_device_monitor_start ()


gboolean
gst_device_monitor_start (GstDeviceMonitor *monitor);


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.




Parameters











monitor


A GstDeviceMonitor

 









Returns


 TRUE if the device monitoring could be started






Since 1.4








gst_device_monitor_stop ()


void
gst_device_monitor_stop (GstDeviceMonitor *monitor);


Stops monitoring the devices.




Parameters











monitor


A GstDeviceProvider

 







Since 1.4








gst_device_monitor_get_devices ()


GList *
gst_device_monitor_get_devices (GstDeviceMonitor *monitor);


Gets a list of devices from all of the relevant monitors. This may actually
probe the hardware if the monitor is not currently started.




Parameters











monitor


A GstDeviceProvider

 









Returns


 a GList of
GstDevice. 


[transfer full][element-type GstDevice]




Since 1.4








Types and Values




struct GstDeviceMonitor


struct GstDeviceMonitor {
  GstObject                parent;
};



Opaque device monitor object structure.




Members











GstObject parent;


the parent GstObject structure

 







Since 1.4








struct GstDeviceMonitorClass


struct GstDeviceMonitorClass {
  GstObjectClass           parent_class;
};



Opaque device monitor class structure.




Members











GstObjectClass parent_class;


the parent GstObjectClass structure

 







Since 1.4








See Also


GstDevice, GstDeviceProvider









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