rtpbin: add support for AUX sender and receiver

AUX elements are elements that can be inserted into the rtpbin pipeline right before or after 1 or more session elements. The AUX elements are essential for implementing functionality such as error correction (FEC) and retransmission (RTX). Fixes https://bugzilla.gnome.org/show_bug.cgi?id=711087
2024-11-30 13:41:48 +00:00 · 2013-12-31 12:31:25 +01:00 · 2013-12-31 12:31:25 +01:00 · d08e05b4ef
commit d08e05b4ef
parent 841f9ad050
2 changed files with 412 additions and 150 deletions
--- a/gst/rtpmanager/gstrtpbin.c
+++ b/gst/rtpmanager/gstrtpbin.c
@ -259,6 +259,9 @@ enum

  SIGNAL_NEW_JITTERBUFFER,

+  SIGNAL_REQUEST_AUX_SENDER,
+  SIGNAL_REQUEST_AUX_RECEIVER,
+
  LAST_SIGNAL
 };

@ -1983,6 +1986,41 @@ gst_rtp_bin_class_init (GstRtpBinClass * klass)
          new_jitterbuffer), NULL, NULL, g_cclosure_marshal_generic,
      G_TYPE_NONE, 3, GST_TYPE_ELEMENT, G_TYPE_UINT, G_TYPE_UINT);

+  /**
+   * GstRtpBin::request-aux-sender:
+   * @rtpbin: the object which received the signal
+   * @session: the session
+   *
+   * Request an AUX sender element for the given @session. The AUX
+   * element will be added to the bin.
+   *
+   * If no handler is connected, no AUX element will be used.
+   *
+   * Since: 1.4
+   */
+  gst_rtp_bin_signals[SIGNAL_REQUEST_AUX_SENDER] =
+      g_signal_new ("request-aux-sender", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstRtpBinClass,
+          request_aux_sender), _gst_element_accumulator, NULL,
+      g_cclosure_marshal_generic, GST_TYPE_ELEMENT, 1, G_TYPE_UINT);
+  /**
+   * GstRtpBin::request-aux-receiver:
+   * @rtpbin: the object which received the signal
+   * @session: the session
+   *
+   * Request an AUX receiver element for the given @session. The AUX
+   * element will be added to the bin.
+   *
+   * If no handler is connected, no AUX element will be used.
+   *
+   * Since: 1.4
+   */
+  gst_rtp_bin_signals[SIGNAL_REQUEST_AUX_RECEIVER] =
+      g_signal_new ("request-aux-receiver", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstRtpBinClass,
+          request_aux_receiver), _gst_element_accumulator, NULL,
+      g_cclosure_marshal_generic, GST_TYPE_ELEMENT, 1, G_TYPE_UINT);
+
  g_object_class_install_property (gobject_class, PROP_SDES,
      g_param_spec_boxed ("sdes", "SDES",
          "The SDES items of this session",
@ -2856,6 +2894,91 @@ no_stream:
  }
 }

+static gboolean
+complete_session_sink (GstRtpBin * rtpbin, GstRtpBinSession * session)
+{
+  gchar *gname;
+  guint sessid = session->id;
+  GstPad *recv_rtp_sink;
+  GstElement *decoder;
+  GstElementClass *klass;
+  GstPadTemplate *templ;
+
+  /* get recv_rtp pad and store */
+  session->recv_rtp_sink =
+      gst_element_get_request_pad (session->session, "recv_rtp_sink");
+  if (session->recv_rtp_sink == NULL)
+    goto pad_failed;
+
+  g_signal_connect (session->recv_rtp_sink, "notify::caps",
+      (GCallback) caps_changed, session);
+
+  GST_DEBUG_OBJECT (rtpbin, "requesting RTP decoder");
+  decoder = session_request_element (session, SIGNAL_REQUEST_RTP_DECODER);
+  if (decoder) {
+    GstPad *decsrc, *decsink;
+    GstPadLinkReturn ret;
+
+    GST_DEBUG_OBJECT (rtpbin, "linking RTP decoder");
+    decsink = gst_element_get_static_pad (decoder, "rtp_sink");
+    if (decsink == NULL)
+      goto dec_sink_failed;
+
+    recv_rtp_sink = decsink;
+
+    decsrc = gst_element_get_static_pad (decoder, "rtp_src");
+    if (decsrc == NULL)
+      goto dec_src_failed;
+
+    ret = gst_pad_link (decsrc, session->recv_rtp_sink);
+    gst_object_unref (decsrc);
+
+    if (ret != GST_PAD_LINK_OK)
+      goto dec_link_failed;
+
+  } else {
+    GST_DEBUG_OBJECT (rtpbin, "no RTP decoder given");
+    recv_rtp_sink = gst_object_ref (session->recv_rtp_sink);
+  }
+
+  GST_DEBUG_OBJECT (rtpbin, "ghosting session sink pad");
+  klass = GST_ELEMENT_GET_CLASS (rtpbin);
+  gname = g_strdup_printf ("recv_rtp_sink_%u", sessid);
+  templ = gst_element_class_get_pad_template (klass, "recv_rtp_sink_%u");
+  session->recv_rtp_sink_ghost =
+      gst_ghost_pad_new_from_template (gname, recv_rtp_sink, templ);
+  gst_object_unref (recv_rtp_sink);
+  gst_pad_set_active (session->recv_rtp_sink_ghost, TRUE);
+  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->recv_rtp_sink_ghost);
+  g_free (gname);
+
+  return TRUE;
+
+  /* ERRORS */
+pad_failed:
+  {
+    g_warning ("rtpbin: failed to get session recv_rtp_sink pad");
+    return FALSE;
+  }
+dec_sink_failed:
+  {
+    g_warning ("rtpbin: failed to get decoder sink pad for session %d", sessid);
+    return FALSE;
+  }
+dec_src_failed:
+  {
+    g_warning ("rtpbin: failed to get decoder src pad for session %d", sessid);
+    gst_object_unref (recv_rtp_sink);
+    return FALSE;
+  }
+dec_link_failed:
+  {
+    g_warning ("rtpbin: failed to link rtp decoder for session %d", sessid);
+    gst_object_unref (recv_rtp_sink);
+    return FALSE;
+  }
+}
+
 /* Create a pad for receiving RTP for the session in @name. Must be called with
 * RTP_BIN_LOCK.
 */
@ -2863,8 +2986,8 @@ static GstPad *
 create_recv_rtp (GstRtpBin * rtpbin, GstPadTemplate * templ, const gchar * name)
 {
  guint sessid;
-  GstElement *decoder;
-  GstPad *sinkdpad, *decsink;
+  GstElement *aux;
+  GstPad *recv_rtp_src;
  GstRtpBinSession *session;

  /* first get the session number */
@ -2887,69 +3010,61 @@ create_recv_rtp (GstRtpBin * rtpbin, GstPadTemplate * templ, const gchar * name)
  if (session->recv_rtp_sink_ghost != NULL)
    return session->recv_rtp_sink_ghost;

-  GST_DEBUG_OBJECT (rtpbin, "getting RTP sink pad");
-  /* get recv_rtp pad and store */
-  session->recv_rtp_sink =
-      gst_element_get_request_pad (session->session, "recv_rtp_sink");
-  if (session->recv_rtp_sink == NULL)
-    goto pad_failed;
+  /* setup the session sink pad */
+  if (!complete_session_sink (rtpbin, session))
+    goto session_sink_failed;

-  g_signal_connect (session->recv_rtp_sink, "notify::caps",
-      (GCallback) caps_changed, session);
-
-  GST_DEBUG_OBJECT (rtpbin, "requesting RTP decoder");
-  decoder = session_request_element (session, SIGNAL_REQUEST_RTP_DECODER);
-  if (decoder) {
-    GstPad *decsrc;
-    GstPadLinkReturn ret;
-
-    GST_DEBUG_OBJECT (rtpbin, "linking RTP decoder");
-    decsink = gst_element_get_static_pad (decoder, "rtp_sink");
-    decsrc = gst_element_get_static_pad (decoder, "rtp_src");
-
-    if (decsink == NULL)
-      goto dec_sink_failed;
-
-    if (decsrc == NULL)
-      goto dec_src_failed;
-
-    ret = gst_pad_link (decsrc, session->recv_rtp_sink);
-    gst_object_unref (decsrc);
-
-    if (ret != GST_PAD_LINK_OK)
-      goto dec_link_failed;
-  } else {
-    GST_DEBUG_OBJECT (rtpbin, "no RTP decoder given");
-    decsink = gst_object_ref (session->recv_rtp_sink);
-  }
-
-  GST_DEBUG_OBJECT (rtpbin, "getting RTP src pad");
-  /* get srcpad, link to SSRCDemux */
  session->recv_rtp_src =
      gst_element_get_static_pad (session->session, "recv_rtp_src");
  if (session->recv_rtp_src == NULL)
-    goto src_pad_failed;
+    goto pad_failed;

-  GST_DEBUG_OBJECT (rtpbin, "getting demuxer RTP sink pad");
-  sinkdpad = gst_element_get_static_pad (session->demux, "sink");
-  GST_DEBUG_OBJECT (rtpbin, "linking demuxer RTP sink pad");
-  gst_pad_link_full (session->recv_rtp_src, sinkdpad,
-      GST_PAD_LINK_CHECK_NOTHING);
-  gst_object_unref (sinkdpad);
+  /* find out if we need AUX elements or if we can go into the SSRC demuxer
+   * directly */
+  aux = session_request_element (session, SIGNAL_REQUEST_AUX_RECEIVER);
+  if (aux) {
+    gchar *pname;
+    GstPad *auxsink;
+    GstPadLinkReturn ret;

-  /* connect to the new-ssrc-pad signal of the SSRC demuxer */
-  session->demux_newpad_sig = g_signal_connect (session->demux,
-      "new-ssrc-pad", (GCallback) new_ssrc_pad_found, session);
-  session->demux_padremoved_sig = g_signal_connect (session->demux,
-      "removed-ssrc-pad", (GCallback) ssrc_demux_pad_removed, session);
+    GST_DEBUG_OBJECT (rtpbin, "linking AUX receiver");

-  GST_DEBUG_OBJECT (rtpbin, "ghosting session sink pad");
-  session->recv_rtp_sink_ghost =
-      gst_ghost_pad_new_from_template (name, decsink, templ);
-  gst_object_unref (decsink);
-  gst_pad_set_active (session->recv_rtp_sink_ghost, TRUE);
-  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->recv_rtp_sink_ghost);
+    pname = g_strdup_printf ("sink_%d", sessid);
+    auxsink = gst_element_get_static_pad (aux, pname);
+    g_free (pname);
+    if (auxsink == NULL)
+      goto aux_sink_failed;

+    ret = gst_pad_link (session->recv_rtp_src, auxsink);
+    gst_object_unref (auxsink);
+    if (ret != GST_PAD_LINK_OK)
+      goto aux_link_failed;
+
+    /* this can be NULL when this AUX element is not to be linked to
+     * an SSRC demuxer */
+    pname = g_strdup_printf ("src_%d", sessid);
+    recv_rtp_src = gst_element_get_static_pad (aux, pname);
+    g_free (pname);
+  } else {
+    recv_rtp_src = gst_object_ref (session->recv_rtp_src);
+  }
+
+  if (recv_rtp_src) {
+    GstPad *sinkdpad;
+
+    GST_DEBUG_OBJECT (rtpbin, "getting demuxer RTP sink pad");
+    sinkdpad = gst_element_get_static_pad (session->demux, "sink");
+    GST_DEBUG_OBJECT (rtpbin, "linking demuxer RTP sink pad");
+    gst_pad_link_full (recv_rtp_src, sinkdpad, GST_PAD_LINK_CHECK_NOTHING);
+    gst_object_unref (recv_rtp_src);
+    gst_object_unref (sinkdpad);
+
+    /* connect to the new-ssrc-pad signal of the SSRC demuxer */
+    session->demux_newpad_sig = g_signal_connect (session->demux,
+        "new-ssrc-pad", (GCallback) new_ssrc_pad_found, session);
+    session->demux_padremoved_sig = g_signal_connect (session->demux,
+        "removed-ssrc-pad", (GCallback) ssrc_demux_pad_removed, session);
+  }
  return session->recv_rtp_sink_ghost;

  /* ERRORS */
@ -2963,32 +3078,24 @@ create_error:
    /* create_session already warned */
    return NULL;
  }
+session_sink_failed:
+  {
+    /* warning already done */
+    return NULL;
+  }
 pad_failed:
  {
-    g_warning ("rtpbin: failed to get session rtp_sink pad");
+    g_warning ("rtpbin: failed to get session recv_rtp_src pad");
    return NULL;
  }
-dec_sink_failed:
+aux_sink_failed:
  {
-    g_warning ("rtpbin: failed to get decoder sink pad for session %d", sessid);
+    g_warning ("rtpbin: failed to get AUX sink pad for session %d", sessid);
    return NULL;
  }
-dec_src_failed:
+aux_link_failed:
  {
-    g_warning ("rtpbin: failed to get decoder src pad for session %d", sessid);
-    gst_object_unref (decsink);
-    return NULL;
-  }
-dec_link_failed:
-  {
-    g_warning ("rtpbin: failed to link rtp decoder for session %d", sessid);
-    gst_object_unref (decsink);
-    return NULL;
-  }
-src_pad_failed:
-  {
-    g_warning ("rtpbin: failed to get session rtp_src pad");
-    gst_object_unref (decsink);
+    g_warning ("rtpbin: failed to link AUX pad to session %d", sessid);
    return NULL;
  }
 }
@ -3168,18 +3275,195 @@ remove_recv_rtcp (GstRtpBin * rtpbin, GstRtpBinSession * session)
  }
 }

+static gboolean
+complete_session_src (GstRtpBin * rtpbin, GstRtpBinSession * session)
+{
+  gchar *gname;
+  guint sessid = session->id;
+  GstPad *send_rtp_src;
+  GstElement *encoder;
+  GstElementClass *klass;
+  GstPadTemplate *templ;
+
+  /* get srcpad */
+  session->send_rtp_src =
+      gst_element_get_static_pad (session->session, "send_rtp_src");
+  if (session->send_rtp_src == NULL)
+    goto no_srcpad;
+
+  GST_DEBUG_OBJECT (rtpbin, "getting RTP encoder");
+  encoder = session_request_element (session, SIGNAL_REQUEST_RTP_ENCODER);
+  if (encoder) {
+    gchar *ename;
+    GstPad *encsrc, *encsink;
+    GstPadLinkReturn ret;
+
+    GST_DEBUG_OBJECT (rtpbin, "linking RTP encoder");
+    ename = g_strdup_printf ("rtp_src_%d", sessid);
+    encsrc = gst_element_get_static_pad (encoder, ename);
+    g_free (ename);
+
+    if (encsrc == NULL)
+      goto enc_src_failed;
+
+    send_rtp_src = encsrc;
+
+    ename = g_strdup_printf ("rtp_sink_%d", sessid);
+    encsink = gst_element_get_static_pad (encoder, ename);
+    g_free (ename);
+    if (encsink == NULL)
+      goto enc_sink_failed;
+
+    ret = gst_pad_link (session->send_rtp_src, encsink);
+    gst_object_unref (encsink);
+
+    if (ret != GST_PAD_LINK_OK)
+      goto enc_link_failed;
+  } else {
+    GST_DEBUG_OBJECT (rtpbin, "no RTP encoder given");
+    send_rtp_src = gst_object_ref (session->send_rtp_src);
+  }
+
+  /* ghost the new source pad */
+  klass = GST_ELEMENT_GET_CLASS (rtpbin);
+  gname = g_strdup_printf ("send_rtp_src_%u", sessid);
+  templ = gst_element_class_get_pad_template (klass, "send_rtp_src_%u");
+  session->send_rtp_src_ghost =
+      gst_ghost_pad_new_from_template (gname, send_rtp_src, templ);
+  gst_object_unref (send_rtp_src);
+  gst_pad_set_active (session->send_rtp_src_ghost, TRUE);
+  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->send_rtp_src_ghost);
+  g_free (gname);
+
+  return TRUE;
+
+  /* ERRORS */
+no_srcpad:
+  {
+    g_warning ("rtpbin: failed to get rtp source pad for session %d", sessid);
+    return FALSE;
+  }
+enc_src_failed:
+  {
+    g_warning ("rtpbin: failed to get encoder src pad for session %d", sessid);
+    return FALSE;
+  }
+enc_sink_failed:
+  {
+    g_warning ("rtpbin: failed to get encoder sink pad for session %d", sessid);
+    gst_object_unref (send_rtp_src);
+    return FALSE;
+  }
+enc_link_failed:
+  {
+    g_warning ("rtpbin: failed to link rtp encoder for session %d", sessid);
+    gst_object_unref (send_rtp_src);
+    return FALSE;
+  }
+}
+
+static gboolean
+setup_aux_sender_fold (const GValue * item, GValue * result, gpointer user_data)
+{
+  GstPad *pad;
+  gchar *name;
+  guint sessid;
+  GstRtpBinSession *session = user_data, *newsess;
+  GstRtpBin *rtpbin = session->bin;
+  GstPadLinkReturn ret;
+
+  pad = g_value_get_object (item);
+  name = gst_pad_get_name (pad);
+
+  if (name == NULL || sscanf (name, "src_%u", &sessid) != 1)
+    goto no_name;
+
+  g_free (name);
+
+  newsess = find_session_by_id (rtpbin, sessid);
+  if (newsess == NULL) {
+    /* create new session */
+    newsess = create_session (rtpbin, sessid);
+    if (newsess == NULL)
+      goto create_error;
+  } else if (newsess->send_rtp_sink != NULL)
+    goto existing_session;
+
+  /* get send_rtp pad and store */
+  newsess->send_rtp_sink =
+      gst_element_get_request_pad (newsess->session, "send_rtp_sink");
+  if (newsess->send_rtp_sink == NULL)
+    goto pad_failed;
+
+  ret = gst_pad_link (pad, newsess->send_rtp_sink);
+  if (ret != GST_PAD_LINK_OK)
+    goto aux_link_failed;
+
+  if (!complete_session_src (rtpbin, newsess))
+    goto session_src_failed;
+
+  return TRUE;
+
+  /* ERRORS */
+no_name:
+  {
+    GST_WARNING ("ignoring invalid pad name %s", GST_STR_NULL (name));
+    g_free (name);
+    return TRUE;
+  }
+create_error:
+  {
+    /* create_session already warned */
+    return FALSE;
+  }
+existing_session:
+  {
+    g_warning ("rtpbin: session %d is already a sender", sessid);
+    return FALSE;
+  }
+pad_failed:
+  {
+    g_warning ("rtpbin: failed to get session pad for session %d", sessid);
+    return FALSE;
+  }
+aux_link_failed:
+  {
+    g_warning ("rtpbin: failed to link AUX for session %d", sessid);
+    return FALSE;
+  }
+session_src_failed:
+  {
+    g_warning ("rtpbin: failed to complete AUX for session %d", sessid);
+    return FALSE;
+  }
+}
+
+static gboolean
+setup_aux_sender (GstRtpBin * rtpbin, GstRtpBinSession * session,
+    GstElement * aux)
+{
+  GstIterator *it;
+  GValue result = { 0, };
+  GstIteratorResult res;
+
+  it = gst_element_iterate_src_pads (aux);
+  res = gst_iterator_fold (it, setup_aux_sender_fold, &result, session);
+  gst_iterator_free (it);
+
+  return res == GST_ITERATOR_DONE;
+}
+
 /* Create a pad for sending RTP for the session in @name. Must be called with
 * RTP_BIN_LOCK.
 */
 static GstPad *
 create_send_rtp (GstRtpBin * rtpbin, GstPadTemplate * templ, const gchar * name)
 {
-  gchar *gname;
+  gchar *pname;
  guint sessid;
-  GstPad *encsrc;
-  GstElement *encoder;
+  GstPad *send_rtp_sink;
+  GstElement *aux;
  GstRtpBinSession *session;
-  GstElementClass *klass;

  /* first get the session number */
  if (name == NULL || sscanf (name, "send_rtp_sink_%u", &sessid) != 1)
@ -3198,64 +3482,41 @@ create_send_rtp (GstRtpBin * rtpbin, GstPadTemplate * templ, const gchar * name)
  if (session->send_rtp_sink_ghost != NULL)
    return session->send_rtp_sink_ghost;

-  /* get send_rtp pad and store */
-  session->send_rtp_sink =
-      gst_element_get_request_pad (session->session, "send_rtp_sink");
-  if (session->send_rtp_sink == NULL)
-    goto pad_failed;
+  /* check if we are already using this session as a sender */
+  if (session->send_rtp_sink != NULL)
+    goto existing_session;

-  session->send_rtp_sink_ghost =
-      gst_ghost_pad_new_from_template (name, session->send_rtp_sink, templ);
-  gst_pad_set_active (session->send_rtp_sink_ghost, TRUE);
-  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->send_rtp_sink_ghost);
+  GST_DEBUG_OBJECT (rtpbin, "getting RTP AUX sender");
+  aux = session_request_element (session, SIGNAL_REQUEST_AUX_SENDER);
+  if (aux) {
+    GST_DEBUG_OBJECT (rtpbin, "linking AUX sender");
+    if (!setup_aux_sender (rtpbin, session, aux))
+      goto aux_session_failed;

-  /* get srcpad */
-  session->send_rtp_src =
-      gst_element_get_static_pad (session->session, "send_rtp_src");
-  if (session->send_rtp_src == NULL)
-    goto no_srcpad;
+    pname = g_strdup_printf ("sink_%d", sessid);
+    send_rtp_sink = gst_element_get_static_pad (aux, pname);
+    g_free (pname);

-  GST_DEBUG_OBJECT (rtpbin, "getting RTP encoder");
-  encoder = session_request_element (session, SIGNAL_REQUEST_RTP_ENCODER);
-  if (encoder) {
-    gchar *ename;
-    GstPad *encsink;
-    GstPadLinkReturn ret;
-
-    GST_DEBUG_OBJECT (rtpbin, "linking RTP encoder");
-    ename = g_strdup_printf ("rtp_sink_%d", sessid);
-    encsink = gst_element_get_static_pad (encoder, ename);
-    g_free (ename);
-    ename = g_strdup_printf ("rtp_src_%d", sessid);
-    encsrc = gst_element_get_static_pad (encoder, ename);
-    g_free (ename);
-
-    if (encsrc == NULL)
-      goto enc_src_failed;
-
-    if (encsink == NULL)
-      goto enc_sink_failed;
-
-    ret = gst_pad_link (session->send_rtp_src, encsink);
-    gst_object_unref (encsink);
-
-    if (ret != GST_PAD_LINK_OK)
-      goto enc_link_failed;
+    if (send_rtp_sink == NULL)
+      goto aux_sink_failed;
  } else {
-    GST_DEBUG_OBJECT (rtpbin, "no RTP encoder given");
-    encsrc = gst_object_ref (session->send_rtp_src);
+    /* get send_rtp pad and store */
+    session->send_rtp_sink =
+        gst_element_get_request_pad (session->session, "send_rtp_sink");
+    if (session->send_rtp_sink == NULL)
+      goto pad_failed;
+
+    if (!complete_session_src (rtpbin, session))
+      goto session_src_failed;
+
+    send_rtp_sink = gst_object_ref (session->send_rtp_sink);
  }

-  /* ghost the new source pad */
-  klass = GST_ELEMENT_GET_CLASS (rtpbin);
-  gname = g_strdup_printf ("send_rtp_src_%u", sessid);
-  templ = gst_element_class_get_pad_template (klass, "send_rtp_src_%u");
-  session->send_rtp_src_ghost =
-      gst_ghost_pad_new_from_template (gname, encsrc, templ);
-  gst_object_unref (encsrc);
-  gst_pad_set_active (session->send_rtp_src_ghost, TRUE);
-  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->send_rtp_src_ghost);
-  g_free (gname);
+  session->send_rtp_sink_ghost =
+      gst_ghost_pad_new_from_template (name, send_rtp_sink, templ);
+  gst_object_unref (send_rtp_sink);
+  gst_pad_set_active (session->send_rtp_sink_ghost, TRUE);
+  gst_element_add_pad (GST_ELEMENT_CAST (rtpbin), session->send_rtp_sink_ghost);

  return session->send_rtp_sink_ghost;

@ -3270,31 +3531,29 @@ create_error:
    /* create_session already warned */
    return NULL;
  }
+existing_session:
+  {
+    g_warning ("rtpbin: session %d is already in use", sessid);
+    return NULL;
+  }
+aux_session_failed:
+  {
+    g_warning ("rtpbin: failed to get AUX sink pad for session %d", sessid);
+    return NULL;
+  }
+aux_sink_failed:
+  {
+    g_warning ("rtpbin: failed to get AUX sink pad for session %d", sessid);
+    return NULL;
+  }
 pad_failed:
  {
    g_warning ("rtpbin: failed to get session pad for session %d", sessid);
    return NULL;
  }
-no_srcpad:
+session_src_failed:
  {
-    g_warning ("rtpbin: failed to get rtp source pad for session %d", sessid);
-    return NULL;
-  }
-enc_src_failed:
-  {
-    g_warning ("rtpbin: failed to get encoder src pad for session %d", sessid);
-    return NULL;
-  }
-enc_sink_failed:
-  {
-    g_warning ("rtpbin: failed to get encoder sink pad for session %d", sessid);
-    gst_object_unref (encsrc);
-    return NULL;
-  }
-enc_link_failed:
-  {
-    g_warning ("rtpbin: failed to link rtp encoder for session %d", sessid);
-    gst_object_unref (encsrc);
+    g_warning ("rtpbin: failed to setup source pads for session %d", sessid);
    return NULL;
  }
 }
--- a/gst/rtpmanager/gstrtpbin.h
+++ b/gst/rtpmanager/gstrtpbin.h
@ -103,6 +103,9 @@ struct _GstRtpBinClass {
  GstElement* (*request_rtp_decoder)  (GstRtpBin *rtpbin, guint session);
  GstElement* (*request_rtcp_encoder) (GstRtpBin *rtpbin, guint session);
  GstElement* (*request_rtcp_decoder) (GstRtpBin *rtpbin, guint session);
+
+  GstElement* (*request_aux_sender)   (GstRtpBin *rtpbin, guint session);
+  GstElement* (*request_aux_receiver) (GstRtpBin *rtpbin, guint session);
 };

 GType gst_rtp_bin_get_type (void);