rtpdtmfsrc

rtpdtmfsrc — Generates RTP DTMF packets

Synopsis

struct              GstRTPDTMFSrc;

Object Hierarchy

  GObject
   +----GInitiallyUnowned
         +----GstObject
               +----GstElement
                     +----GstBaseSrc
                           +----GstRTPDTMFSrc

Properties

  "clock-rate"               guint                 : Read / Write
  "packet-redundancy"        guint                 : Read / Write
  "pt"                       guint                 : Read / Write
  "seqnum"                   guint                 : Read
  "seqnum-offset"            gint                  : Read / Write
  "ssrc"                     guint                 : Read / Write
  "timestamp"                guint                 : Read
  "timestamp-offset"         gint                  : Read / Write

Description

The RTPDTMFSrc element generates RTP DTMF (RFC 2833) event packets on request from application. The application communicates the beginning and end of a DTMF event using custom upstream gstreamer events. To report a DTMF event, an application must send an event of type GST_EVENT_CUSTOM_UPSTREAM, having a structure of name "dtmf-event" with fields set according to the following table:

Name GType Possible values Purpose
type G_TYPE_INT 0-1 The application uses this field to specify which of the two methods specified in RFC 2833 to use. The value should be 0 for tones and 1 for named events. Tones are specified by their frequencies and events are specied by their number. This element can only take events as input. Do not confuse with "method" which specified the output.
number G_TYPE_INT 0-15 The event number.
volume G_TYPE_INT 0-36 This field describes the power level of the tone, expressed in dBm0 after dropping the sign. Power levels range from 0 to -63 dBm0. The range of valid DTMF is from 0 to -36 dBm0. Can be omitted if start is set to FALSE.
start G_TYPE_BOOLEAN True or False Whether the event is starting or ending.
method G_TYPE_INT 1 The method used for sending event, this element will react if this field is absent or 1.

For example, the following code informs the pipeline (and in turn, the RTPDTMFSrc element inside the pipeline) about the start of an RTP DTMF named event '1' of volume -25 dBm0:

structure = gst_structure_new ("dtmf-event",
                   "type", G_TYPE_INT, 1,
                   "number", G_TYPE_INT, 1,
                   "volume", G_TYPE_INT, 25,
                   "start", G_TYPE_BOOLEAN, TRUE, NULL);

event = gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM, structure);
gst_element_send_event (pipeline, event);

When a DTMF tone actually starts or stop, a "dtmf-event-processed" element GstMessage with the same fields as the "dtmf-event" GstEvent that was used to request the event. Also, if any event has not been processed when the element goes from the PAUSED to the READY state, then a "dtmf-event-dropped" message is posted on the GstBus in the order that they were received.

Synopsis

Element Information

plugin

dtmf

author

Zeeshan Ali <zeeshan.ali@nokia.com>

class

Source/Network

Element Pads

name

src

direction

source

presence

always

details

application/x-rtp, media=(string)audio, payload=(int)[ 96, 127 ], clock-rate=(int)[ 0, 2147483647 ], encoding-name=(string)TELEPHONE-EVENT

Details

struct GstRTPDTMFSrc

struct GstRTPDTMFSrc;

The opaque GstRTPDTMFSrc data structure.

Property Details

The "clock-rate" property

  "clock-rate"               guint                 : Read / Write

The clock-rate at which to generate the dtmf packets.

Default value: 8000


The "packet-redundancy" property

  "packet-redundancy"        guint                 : Read / Write

Number of packets to send to indicate start and stop dtmf events.

Allowed values: [1,5]

Default value: 1


The "pt" property

  "pt"                       guint                 : Read / Write

The payload type of the packets.

Allowed values: <= 128

Default value: 96


The "seqnum" property

  "seqnum"                   guint                 : Read

The RTP sequence number of the last processed packet.

Default value: 0


The "seqnum-offset" property

  "seqnum-offset"            gint                  : Read / Write

Offset to add to all outgoing seqnum (-1 = random).

Allowed values: >= G_MAXULONG

Default value: -1


The "ssrc" property

  "ssrc"                     guint                 : Read / Write

The SSRC of the packets (-1 == random).

Default value: 4294967295


The "timestamp" property

  "timestamp"                guint                 : Read

The RTP timestamp of the last processed packet.

Default value: 0


The "timestamp-offset" property

  "timestamp-offset"         gint                  : Read / Write

Offset to add to all outgoing timestamps (-1 = random).

Allowed values: >= G_MAXULONG

Default value: -1

See Also

dtmfsrc, rtpdtmfdepay, rtpdtmfmux