## GstDeviceProvider

GstDeviceProvider — A device provider

## Functions

gboolean | gst_device_provider_can_monitor ()
void | gst_device_provider_class_add_metadata ()
void | gst_device_provider_class_add_static_metadata ()
const gchar * | gst_device_provider_class_get_metadata ()
void | gst_device_provider_class_set_metadata ()
void | gst_device_provider_class_set_static_metadata ()
void | gst_device_provider_device_add ()
void | gst_device_provider_device_remove ()
void | gst_device_provider_device_changed ()
GstBus * | gst_device_provider_get_bus ()
GList * | gst_device_provider_get_devices ()
GstDeviceProviderFactory * | gst_device_provider_get_factory ()
const gchar * | gst_device_provider_get_metadata ()
gboolean | gst_device_provider_register ()
gboolean | gst_device_provider_start ()
void | gst_device_provider_stop ()

## Types and Values

struct | GstDeviceProvider
struct | GstDeviceProviderClass

## Includes

    #include <gst/gst.h>

## Description

A GstDeviceProvider subclass is provided by a plugin that handles devices if there is a way to programmatically list connected devices. It can also optionally provide updates to the list of connected devices.

Each GstDeviceProvider subclass is a singleton, a plugin should normally provide a single subclass for all devices.

Applications would normally use a GstDeviceMonitor to monitor devices from all relevant providers.

## Functions

### gst_device_provider_can_monitor ()

    gboolean
    gst_device_provider_can_monitor (GstDeviceProvider *provider);

### gst_device_provider_class_add_metadata ()

    void
    gst_device_provider_class_add_metadata
                                   (GstDeviceProviderClass *klass,
                                    const gchar *key,
                                    const gchar *value);

Set `key` with `value` as metadata in `klass` .

#### Parameters

klass | class to set metadata for |
key | the key to set |
value | the value to set |

Since: 1.4

### gst_device_provider_class_add_static_metadata ()

    void
    gst_device_provider_class_add_static_metadata
                                   (GstDeviceProviderClass *klass,
                                    const gchar *key,
                                    const gchar *value);

Set `key` with `value` as metadata in `klass` .

Same as `gst_device_provider_class_add_metadata()`, but `value` must be a static string or an inlined string, as it will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)

#### Parameters

klass | class to set metadata for |
key | the key to set |
value | the value to set. | [transfer full]

Since: 1.4

### gst_device_provider_class_get_metadata ()

    const gchar *
    gst_device_provider_class_get_metadata
                                   (GstDeviceProviderClass *klass,
                                    const gchar *key);

Get metadata with `key` in `klass` .

#### Parameters

klass | class to get metadata for |
key | the key to get |

#### Returns

the metadata for `key` .

[nullable]

Since: 1.4

### gst_device_provider_class_set_metadata ()

    void
    gst_device_provider_class_set_metadata
                                   (GstDeviceProviderClass *klass,
                                    const gchar *longname,
                                    const gchar *classification,
                                    const gchar *description,
                                    const gchar *author);

Sets the detailed information for a GstDeviceProviderClass.

> This function is for use in _class_init functions only.

#### Parameters

klass | class to set metadata for |
longname | The long English name of the device provider. E.g. "File Sink" |
classification | String describing the type of device provider, as an unordered list separated with slashes ('/'). See draft-klass.txt of the design docs for more details and common types. E.g: "Sink/File" |
description | Sentence describing the purpose of the device provider. E.g: "Write stream to a file" |
author | Name and contact details of the author(s). Use \n to separate multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>" |

Since: 1.4

### gst_device_provider_class_set_static_metadata ()

    void
    gst_device_provider_class_set_static_metadata
                                   (GstDeviceProviderClass *klass,
                                    const gchar *longname,
                                    const gchar *classification,
                                    const gchar *description,
                                    const gchar *author);

Sets the detailed information for a GstDeviceProviderClass.

> This function is for use in _class_init functions only.

Same as `gst_device_provider_class_set_metadata()`, but `longname` , `classification` , `description` , and `author` must be static strings or inlined strings, as they will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)

#### Parameters

klass | class to set metadata for |
longname | The long English name of the element. E.g. "File Sink". | [transfer full]
classification | String describing the type of element, as an unordered list separated with slashes ('/'). See draft-klass.txt of the design docs for more details and common types. E.g: "Sink/File". | [transfer full]
description | Sentence describing the purpose of the element. E.g: "Write stream to a file". | [transfer full]
author | Name and contact details of the author(s). Use \n to separate multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>". | [transfer full]

Since: 1.4

### gst_device_provider_device_add ()

    void
    gst_device_provider_device_add (GstDeviceProvider *provider,
                                    GstDevice *device);

Posts a message on the provider's GstBus to inform applications that a new device has been added.

This is for use by subclasses.

`device` 's reference count will be incremented, and any floating reference will be removed (see `gst_object_ref_sink()`).

#### Parameters

provider | a GstDeviceProvider |
device | a GstDevice that has been added. | [transfer floating]

Since: 1.4

### gst_device_provider_device_remove ()

    void
    gst_device_provider_device_remove (GstDeviceProvider *provider,
                                       GstDevice *device);

Posts a message on the provider's GstBus to inform applications that a device has been removed.

This is for use by subclasses.

#### Parameters

provider | a GstDeviceProvider |
device | a GstDevice that has been removed |

Since: 1.4

### gst_device_provider_device_changed ()

    void
    gst_device_provider_device_changed (GstDeviceProvider *provider,
                                        GstDevice *device,
                                        GstDevice *changed_device);

This function is used when `changed_device` was modified into its new form `device` . This will post a `DEVICE_CHANGED` message on the bus to let the application know that the device was modified. GstDevice is immutable for MT. safety purposes so this is an "atomic" way of letting the application know when a device was modified.

#### Parameters

device | the new version of `changed_device` . | [transfer none]
changed_device | the old version of the device that has been udpated. | [transfer floating]

Since: 1.16

### gst_device_provider_get_bus ()

    GstBus *
    gst_device_provider_get_bus (GstDeviceProvider *provider);

Gets the GstBus of this GstDeviceProvider

#### Parameters

provider | a GstDeviceProvider |

#### Returns

a GstBus.

[transfer full]

Since: 1.4

### gst_device_provider_get_devices ()

    GList *
    gst_device_provider_get_devices (GstDeviceProvider *provider);

Gets a list of devices that this provider understands. This may actually probe the hardware if the provider is not currently started.

#### Parameters

provider | A GstDeviceProvider |

#### Returns

a GList of GstDevice.

[transfer full][element-type GstDevice]

Since: 1.4

### gst_device_provider_get_factory ()

    GstDeviceProviderFactory *
    gst_device_provider_get_factory (GstDeviceProvider *provider);

Retrieves the factory that was used to create this device provider.

#### Parameters

provider | a GstDeviceProvider to request the device provider factory of. |

#### Returns

the GstDeviceProviderFactory used for creating this device provider. no refcounting is needed.

[transfer none]

Since: 1.4

### gst_device_provider_get_metadata ()

    const gchar *
    gst_device_provider_get_metadata (GstDeviceProvider *provider,
                                      const gchar *key);

Get metadata with `key` in `provider` .

#### Parameters

provider | provider to get metadata for |
key | the key to get |

#### Returns

the metadata for `key` .

Since: 1.14

### gst_device_provider_register ()

    gboolean
    gst_device_provider_register (GstPlugin *plugin,
                                  const gchar *name,
                                  guint rank,
                                  GType type);

Create a new device providerfactory capable of instantiating objects of the `type` and add the factory to `plugin` .

#### Parameters

plugin | GstPlugin to register the device provider with, or `NULL` for a static device provider. | [allow-none]
name | name of device providers of this type |
rank | rank of device provider (higher rank means more importance when autoplugging) |
type | GType of device provider to register |

#### Returns

`TRUE`, if the registering succeeded, `FALSE` on error

Since: 1.4

### gst_device_provider_start ()

    gboolean
    gst_device_provider_start (GstDeviceProvider *provider);

Starts providering the devices. This will cause GST_MESSAGE_DEVICE_ADDED and GST_MESSAGE_DEVICE_REMOVED messages to be posted on the provider's bus when devices are added or removed from the system.

Since the GstDeviceProvider is a singleton, `gst_device_provider_start()` may already have been called by another user of the object, `gst_device_provider_stop()` needs to be called the same number of times.

#### Parameters

provider | A GstDeviceProvider |

#### Returns

`TRUE` if the device providering could be started

Since: 1.4

### gst_device_provider_stop ()

    void
    gst_device_provider_stop (GstDeviceProvider *provider);

Decreases the use-count by one. If the use count reaches zero, this GstDeviceProvider will stop providering the devices. This needs to be called the same number of times that `gst_device_provider_start()` was called.

#### Parameters

provider | A GstDeviceProvider |

Since: 1.4

## Types and Values

### struct GstDeviceProvider

    struct GstDeviceProvider {
      GstObject         parent;

      /* Protected by the Object lock */
      GList *devices;
    };

The structure of the base GstDeviceProvider

#### Members

GstObject `parent`; | The parent GstObject |
GList *`devices`; | a GList of the GstDevice objects |

Since: 1.4

### struct GstDeviceProviderClass

    struct GstDeviceProviderClass {
      GstObjectClass    parent_class;

      GstDeviceProviderFactory     *factory;

      GList*      (*probe) (GstDeviceProvider * provider);

      gboolean    (*start) (GstDeviceProvider * provider);
      void        (*stop)  (GstDeviceProvider * provider);
    };

The structure of the base GstDeviceProviderClass

#### Members

GstDeviceProviderFactory *`factory`; | a pointer to the GstDeviceProviderFactory that creates this provider |
`probe` () | Returns a list of devices that are currently available. This should never block. |
`start` () | Starts monitoring for new devices. Only subclasses that can know that devices have been added or remove need to implement this method. |
`stop` () | Stops monitoring for new devices. Only subclasses that implement the `start()` method need to implement this method. |

Since: 1.4

## See Also

GstDevice, GstDeviceMonitor