## FsTransmitter

FsTransmitter — A transmitter object linked to a session

## Synopsis

    #include <gst/farsight/fs-transmitter.h>

                        FsTransmitter;
                        FsTransmitterClass;
    FsTransmitter*      fs_transmitter_new                  (const gchar *type,
                                                             guint components,
                                                             GError **error);
    FsStreamTransmitter* fs_transmitter_new_stream_transmitter
                                                            (FsTransmitter *transmitter,
                                                             FsParticipant *participant,
                                                             guint n_parameters,
                                                             GParameter *parameters,
                                                             GError **error);
    GType               fs_transmitter_get_stream_transmitter_type
                                                            (FsTransmitter *transmitter);
    void                fs_transmitter_emit_error           (FsTransmitter *transmitter,
                                                             gint error_no,
                                                             const gchar *error_msg,
                                                             const gchar *debug_msg);
    GstElement*         fs_transmitter_get_recvonly_filter  (FsTransmitter *transmitter,
                                                             guint component);
    char**              fs_transmitter_list_available       (void);

## Object Hierarchy

      GObject
       +----FsTransmitter

## Properties

      "components"               guint                 : Read / Write / Construct Only
      "gst-sink"                 GstElement*           : Read
      "gst-src"                  GstElement*           : Read

## Signals

      "error"                                          : Run Last
      "get-recvonly-filter"                            : Run Last

## Description

This object is the base implementation of a Farsight Transmitter. It needs to be derived and implement by a Farsight transmitter. A Farsight Transmitter provides a GStreamer network sink and source to be used for the Farsight Session. It creates FsStreamTransmitter objects which are used to set the different per-stream properties

## Details

### FsTransmitter

    typedef struct _FsTransmitter FsTransmitter;

All members are private, access them using methods and properties

### FsTransmitterClass

    typedef struct {
      GObjectClass parent_class;

      /*virtual functions */
      FsStreamTransmitter *(*new_stream_transmitter) (FsTransmitter *transmitter,
                                                      FsParticipant *participant,
                                                      guint n_parameters,
                                                      GParameter *parameters,
                                                      GError **error);
      GType (*get_stream_transmitter_type) (FsTransmitter *transmitter);
    } FsTransmitterClass;

You must override both methods in a subclass.

GObjectClass `parent_class`; | Our parent
`new_stream_transmitter` () | Creates a new FsStreamTransmitter
`get_stream_transmitter_type` () | Returns the GType of the stream transmitter created by this class (useful for bindings)

### fs_transmitter_new ()

    FsTransmitter*      fs_transmitter_new                  (const gchar *type,
                                                             guint components,
                                                             GError **error);

This function creates a new transmitter of the requested type. It will load the appropriate plugin as required.

`type` : | The type of transmitter to create
`components` : | The number of components to create
`error` : | location of a GError, or NULL if no error occured
Returns : | a newly-created FsTransmitter of the requested type (or NULL if there is an error)

### fs_transmitter_new_stream_transmitter ()

    FsStreamTransmitter* fs_transmitter_new_stream_transmitter
                                                            (FsTransmitter *transmitter,
                                                             FsParticipant *participant,
                                                             guint n_parameters,
                                                             GParameter *parameters,
                                                             GError **error);

This function will create a new FsStreamTransmitter element for a specific participant for this FsTransmitter

`transmitter` : | a FsTranmitter
`participant` : | the FsParticipant for which the FsStream using this new FsStreamTransmitter is created
`n_parameters` : | The number of parameters to pass to the newly created FsStreamTransmitter
`parameters` : | an array of GParameter
`error` : | location of a GError, or NULL if no error occured
Returns : | a new FsStreamTransmitter, or NULL if there is an error

### fs_transmitter_get_stream_transmitter_type ()

    GType               fs_transmitter_get_stream_transmitter_type
                                                            (FsTransmitter *transmitter);

This function returns the GObject type for the stream transmitter. This is meant for bindings that need to introspect the type of arguments that can be passed to the _new_stream_transmitter.

`transmitter` : | A FsTransmitter object
Returns : | the GType

### fs_transmitter_emit_error ()

    void                fs_transmitter_emit_error           (FsTransmitter *transmitter,
                                                             gint error_no,
                                                             const gchar *error_msg,
                                                             const gchar *debug_msg);

This function emit the "error" signal on a FsTransmitter, it should only be called by subclasses.

`transmitter` : | FsTransmitter on which to emit the error signal
`error_no` : | The number of the error
`error_msg` : | Error message to be displayed to user
`debug_msg` : | Debugging error message

### fs_transmitter_get_recvonly_filter ()

    GstElement*         fs_transmitter_get_recvonly_filter  (FsTransmitter *transmitter,
                                                             guint component);

Get the filter to add on the send pipeline if sending is disabled.

Only for use by subclasses.

`transmitter` : | A FsTransmitter object
`component` : | The component to get the filter for
Returns : | a GstElement to use as the filter or `NULL`

### fs_transmitter_list_available ()

    char**              fs_transmitter_list_available       (void);

Get the list of all available transmitters

Returns : | a newly allocated array of strings containing the list of all available transmitters or `NULL` if there are none. It should be freed with `g_strfreev()`.

## Property Details

### The `"components"` property

      "components"               guint                 : Read / Write / Construct Only

The number of components to create

Allowed values: [1,255]

Default value: 1

### The `"gst-sink"` property

      "gst-sink"                 GstElement*           : Read

A network source GstElement to be used by the FsSession These element's sink must have async=FALSE This element MUST provide a pad named "sink\`d`" per component. These pads number must start at 1 (the \`d` corresponds to the component number). These pads MUST be static pads.

### The `"gst-src"` property

      "gst-src"                  GstElement*           : Read

A network source GstElement to be used by the FsSession This element MUST provide a source pad named "src`d`" per component. These pads number must start at 1 (the `d` corresponds to the component number). These pads MUST be static pads.

## Signal Details

### The `"error"` signal

    void                user_function                      (FsTransmitter *self,
                                                            FsError        errorno,
                                                            gchar         *error_msg,
                                                            gchar         *debug_msg,
                                                            gpointer       user_data)      : Run Last

This signal is emitted in any error condition

`self` : | FsTransmitter that emitted the signal
`errorno` : | The number of the error
`error_msg` : | Error message to be displayed to user
`debug_msg` : | Debugging error message
`user_data` : | user data set when the signal handler was connected.

### The `"get-recvonly-filter"` signal

    GstElement*         user_function                      (FsTransmitter *self,
                                                            guint          component,
                                                            gpointer       user_data)      : Run Last

This signal is emitted when the transmitter wants to get a filter for to use if sending is disabled. If you want to drop all buffers, just don't listen to the signal.

This element should have a "sending" property that can be changed with the sending state of the stream. It should default to `TRUE`.

`self` : | FsTransmitter that emitted the signal
`component` : | The component that the filter will be used for
`user_data` : | user data set when the signal handler was connected.
Returns : | the GstElement to use as the filter, or `NULL` to drop everything