ext/webrtc/transportreceivebin.c - imx-gst-plugins-bad - Git at Google

 /* GStreamer
  * Copyright (C) 2017 Matthew Waters <matthew@centricular.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif

 #include "transportreceivebin.h"
 #include "utils.h"

 /*
  * ,----------------------------transport_receive_%u-----------------------------,
  * ;       (rtp)                                                                 ;
  * ;  ,---nicesrc----,  ,-capsfilter-,  ,----dtlssrtpdec----,      ,--funnel--,  ;
  * ;  ;          src o--o sink   src o--o sink      rtp_src o------o sink_0   ;  ;
  * ;  '--------------'  '------------'  ;                   ;      ;      src o--o rtp_src
  * ;                                    ;          rtcp_src o-, ,--o sink_1   ;  ;
  * ;                                    '-------------------' ; ;  '----------'  ;
  * ;                                                          ; ;  ,--funnel--,  ;
  * ;                                                          '-+--o sink_0   ;  ;
  * ;                                                          ,-'  ;      src o--o rtcp_src
  * ;       (rtcp)                                             ;  ,-o sink_1   ;  ;
  * ;  ,---nicesrc----,  ,-capsfilter-,  ,----dtlssrtpdec----, ;  ; '----------'  ;
  * ;  ;          src o--o sink   src o--o sink      rtp_src o-'  ;               ;
  * ;  '--------------'  '------------'  ;                   ;    ;               ;
  * ;                                    ;          rtcp_src o----'               ;
  * ;                                    '-------------------'                    ;
  * '-----------------------------------------------------------------------------'
  *
  * Do we really wnat to be *that* permissive in what we accept?
  *
  * FIXME: When and how do we want to clear the possibly stored buffers?
  */

 #define GST_CAT_DEFAULT gst_webrtc_transport_receive_bin_debug
 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

 #define transport_receive_bin_parent_class parent_class
 G_DEFINE_TYPE_WITH_CODE (TransportReceiveBin, transport_receive_bin,
     GST_TYPE_BIN,
     GST_DEBUG_CATEGORY_INIT (gst_webrtc_transport_receive_bin_debug,
         "webrtctransportreceivebin", 0, "webrtctransportreceivebin");
     );

 static GstStaticPadTemplate rtp_sink_template =
 GST_STATIC_PAD_TEMPLATE ("rtp_src",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS ("application/x-rtp"));

 static GstStaticPadTemplate rtcp_sink_template =
 GST_STATIC_PAD_TEMPLATE ("rtcp_src",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS ("application/x-rtp"));

 enum
 {
   PROP_0,
   PROP_STREAM,
 };

 static const gchar *
 _receive_state_to_string (ReceiveState state)
 {
   switch (state) {
     case RECEIVE_STATE_BLOCK:
       return "block";
     case RECEIVE_STATE_DROP:
       return "drop";
     case RECEIVE_STATE_PASS:
       return "pass";
     default:
       return "Unknown";
   }
 }

 static GstPadProbeReturn
 pad_block (GstPad * pad, GstPadProbeInfo * info, TransportReceiveBin * receive)
 {
   GstPadProbeReturn ret;

   g_mutex_lock (&receive->pad_block_lock);
   while (receive->receive_state == RECEIVE_STATE_BLOCK) {
     g_cond_wait (&receive->pad_block_cond, &receive->pad_block_lock);
     GST_DEBUG_OBJECT (pad, "probe waited. new state %s",
         _receive_state_to_string (receive->receive_state));
   }
   ret = GST_PAD_PROBE_PASS;

   if (receive->receive_state == RECEIVE_STATE_DROP) {
     ret = GST_PAD_PROBE_DROP;
   } else if (receive->receive_state == RECEIVE_STATE_PASS) {
     ret = GST_PAD_PROBE_OK;
   }

   g_mutex_unlock (&receive->pad_block_lock);

   return ret;
 }

 void
 transport_receive_bin_set_receive_state (TransportReceiveBin * receive,
     ReceiveState state)
 {
   g_mutex_lock (&receive->pad_block_lock);
   receive->receive_state = state;
   GST_DEBUG_OBJECT (receive, "changing receive state to %s",
       _receive_state_to_string (state));
   g_cond_signal (&receive->pad_block_cond);
   g_mutex_unlock (&receive->pad_block_lock);
 }

 static void
 transport_receive_bin_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
   TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

   GST_OBJECT_LOCK (receive);
   switch (prop_id) {
     case PROP_STREAM:
       /* XXX: weak-ref this? */
       receive->stream = TRANSPORT_STREAM (g_value_get_object (value));
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
   GST_OBJECT_UNLOCK (receive);
 }

 static void
 transport_receive_bin_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
   TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

   GST_OBJECT_LOCK (receive);
   switch (prop_id) {
     case PROP_STREAM:
       g_value_set_object (value, receive->stream);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
   GST_OBJECT_UNLOCK (receive);
 }

 static void
 transport_receive_bin_finalize (GObject * object)
 {
   TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

   g_mutex_clear (&receive->pad_block_lock);
   g_cond_clear (&receive->pad_block_cond);

   G_OBJECT_CLASS (parent_class)->finalize (object);
 }

 static GstStateChangeReturn
 transport_receive_bin_change_state (GstElement * element,
     GstStateChange transition)
 {
   TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (element);
   GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

   GST_DEBUG ("changing state: %s => %s",
       gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
       gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));

   switch (transition) {
     case GST_STATE_CHANGE_NULL_TO_READY:{
       GstElement *elem;

       receive->rtp_block =
           _create_pad_block (GST_ELEMENT (receive), receive->rtp_src, 0, NULL,
           NULL);
       receive->rtp_block->block_id =
           gst_pad_add_probe (receive->rtp_src, GST_PAD_PROBE_TYPE_ALL_BOTH,
           (GstPadProbeCallback) pad_block, receive, NULL);

       /* XXX: because nice needs the nicesrc internal main loop running in order
        * correctly STUN... */
       /* FIXME: this races with the pad exposure later and may get not-linked */
       elem = receive->stream->transport->transport->src;
       gst_element_set_locked_state (elem, TRUE);
       gst_element_set_state (elem, GST_STATE_PLAYING);
       elem = receive->stream->rtcp_transport->transport->src;
       gst_element_set_locked_state (elem, TRUE);
       gst_element_set_state (elem, GST_STATE_PLAYING);
       break;
     }
     default:
       break;
   }

   ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
   if (ret == GST_STATE_CHANGE_FAILURE)
     return ret;

   switch (transition) {
     case GST_STATE_CHANGE_READY_TO_NULL:{
       GstElement *elem;

       elem = receive->stream->transport->transport->src;
       gst_element_set_locked_state (elem, FALSE);
       gst_element_set_state (elem, GST_STATE_NULL);
       elem = receive->stream->rtcp_transport->transport->src;
       gst_element_set_locked_state (elem, FALSE);
       gst_element_set_state (elem, GST_STATE_NULL);

       if (receive->rtp_block)
         _free_pad_block (receive->rtp_block);
       receive->rtp_block = NULL;
       break;
     }
     default:
       break;
   }

   return ret;
 }

 static void
 rtp_queue_overrun (GstElement * queue, TransportReceiveBin * receive)
 {
   GST_WARNING_OBJECT (receive, "Internal receive queue overrun. Dropping data");
 }

 static void
 transport_receive_bin_constructed (GObject * object)
 {
   TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);
   GstWebRTCDTLSTransport *transport;
   GstPad *ghost, *pad;
   GstElement *capsfilter, *funnel, *queue;
   GstCaps *caps;

   g_return_if_fail (receive->stream);

   /* link ice src, dtlsrtp together for rtp */
   transport = receive->stream->transport;
   gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->dtlssrtpdec));

   capsfilter = gst_element_factory_make ("capsfilter", NULL);
   caps = gst_caps_new_empty_simple ("application/x-rtp");
   g_object_set (capsfilter, "caps", caps, NULL);
   gst_caps_unref (caps);

   gst_bin_add (GST_BIN (receive), GST_ELEMENT (capsfilter));
   if (!gst_element_link_pads (capsfilter, "src", transport->dtlssrtpdec,
           "sink"))
     g_warn_if_reached ();

   gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->transport->src));

   if (!gst_element_link_pads (GST_ELEMENT (transport->transport->src), "src",
           GST_ELEMENT (capsfilter), "sink"))
     g_warn_if_reached ();

   /* link ice src, dtlsrtp together for rtcp */
   transport = receive->stream->rtcp_transport;
   gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->dtlssrtpdec));

   capsfilter = gst_element_factory_make ("capsfilter", NULL);
   caps = gst_caps_new_empty_simple ("application/x-rtcp");
   g_object_set (capsfilter, "caps", caps, NULL);
   gst_caps_unref (caps);

   gst_bin_add (GST_BIN (receive), GST_ELEMENT (capsfilter));
   if (!gst_element_link_pads (capsfilter, "src", transport->dtlssrtpdec,
           "sink"))
     g_warn_if_reached ();

   gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->transport->src));

   if (!gst_element_link_pads (GST_ELEMENT (transport->transport->src), "src",
           GST_ELEMENT (capsfilter), "sink"))
     g_warn_if_reached ();

   /* create funnel for rtp_src */
   funnel = gst_element_factory_make ("funnel", NULL);
   gst_bin_add (GST_BIN (receive), funnel);
   if (!gst_element_link_pads (receive->stream->transport->dtlssrtpdec,
           "rtp_src", funnel, "sink_0"))
     g_warn_if_reached ();
   if (!gst_element_link_pads (receive->stream->rtcp_transport->dtlssrtpdec,
           "rtp_src", funnel, "sink_1"))
     g_warn_if_reached ();

   queue = gst_element_factory_make ("queue", NULL);
   /* FIXME: make this configurable? */
   g_object_set (queue, "leaky", 2, "max-size-time", (guint64) 0,
       "max-size-buffers", 0, "max-size-bytes", 5 * 1024 * 1024, NULL);
   g_signal_connect (queue, "overrun", G_CALLBACK (rtp_queue_overrun), receive);
   gst_bin_add (GST_BIN (receive), queue);
   if (!gst_element_link_pads (funnel, "src", queue, "sink"))
     g_warn_if_reached ();

   pad = gst_element_get_static_pad (queue, "src");
   receive->rtp_src = gst_ghost_pad_new ("rtp_src", pad);

   gst_element_add_pad (GST_ELEMENT (receive), receive->rtp_src);
   gst_object_unref (pad);

   /* create funnel for rtcp_src */
   funnel = gst_element_factory_make ("funnel", NULL);
   gst_bin_add (GST_BIN (receive), funnel);
   if (!gst_element_link_pads (receive->stream->transport->dtlssrtpdec,
           "rtcp_src", funnel, "sink_0"))
     g_warn_if_reached ();
   if (!gst_element_link_pads (receive->stream->rtcp_transport->dtlssrtpdec,
           "rtcp_src", funnel, "sink_1"))
     g_warn_if_reached ();

   pad = gst_element_get_static_pad (funnel, "src");
   ghost = gst_ghost_pad_new ("rtcp_src", pad);
   gst_element_add_pad (GST_ELEMENT (receive), ghost);
   gst_object_unref (pad);

   G_OBJECT_CLASS (parent_class)->constructed (object);
 }

 static void
 transport_receive_bin_class_init (TransportReceiveBinClass * klass)
 {
   GObjectClass *gobject_class = (GObjectClass *) klass;
   GstElementClass *element_class = (GstElementClass *) klass;

   element_class->change_state = transport_receive_bin_change_state;

   gst_element_class_add_static_pad_template (element_class, &rtp_sink_template);
   gst_element_class_add_static_pad_template (element_class,
       &rtcp_sink_template);

   gst_element_class_set_metadata (element_class, "WebRTC Transport Receive Bin",
       "Filter/Network/WebRTC", "A bin for webrtc connections",
       "Matthew Waters <matthew@centricular.com>");

   gobject_class->constructed = transport_receive_bin_constructed;
   gobject_class->get_property = transport_receive_bin_get_property;
   gobject_class->set_property = transport_receive_bin_set_property;
   gobject_class->finalize = transport_receive_bin_finalize;

   g_object_class_install_property (gobject_class,
       PROP_STREAM,
       g_param_spec_object ("stream", "Stream",
           "The TransportStream for this receiveing bin",
           transport_stream_get_type (),
           G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
 }

 static void
 transport_receive_bin_init (TransportReceiveBin * receive)
 {
   g_mutex_init (&receive->pad_block_lock);
   g_cond_init (&receive->pad_block_cond);
 }
	/* GStreamer
	* Copyright (C) 2017 Matthew Waters <matthew@centricular.com>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	#ifdef HAVE_CONFIG_H
	# include "config.h"
	#endif

	#include "transportreceivebin.h"
	#include "utils.h"

	/*
	* ,----------------------------transport_receive_%u-----------------------------,
	* ; (rtp) ;
	* ; ,---nicesrc----, ,-capsfilter-, ,----dtlssrtpdec----, ,--funnel--, ;
	* ; ; src o--o sink src o--o sink rtp_src o------o sink_0 ; ;
	* ; '--------------' '------------' ; ; ; src o--o rtp_src
	* ; ; rtcp_src o-, ,--o sink_1 ; ;
	* ; '-------------------' ; ; '----------' ;
	* ; ; ; ,--funnel--, ;
	* ; '-+--o sink_0 ; ;
	* ; ,-' ; src o--o rtcp_src
	* ; (rtcp) ; ,-o sink_1 ; ;
	* ; ,---nicesrc----, ,-capsfilter-, ,----dtlssrtpdec----, ; ; '----------' ;
	* ; ; src o--o sink src o--o sink rtp_src o-' ; ;
	* ; '--------------' '------------' ; ; ; ;
	* ; ; rtcp_src o----' ;
	* ; '-------------------' ;
	* '-----------------------------------------------------------------------------'
	*
	* Do we really wnat to be that permissive in what we accept?
	*
	* FIXME: When and how do we want to clear the possibly stored buffers?
	*/

	#define GST_CAT_DEFAULT gst_webrtc_transport_receive_bin_debug
	GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

	#define transport_receive_bin_parent_class parent_class
	G_DEFINE_TYPE_WITH_CODE (TransportReceiveBin, transport_receive_bin,
	GST_TYPE_BIN,
	GST_DEBUG_CATEGORY_INIT (gst_webrtc_transport_receive_bin_debug,
	"webrtctransportreceivebin", 0, "webrtctransportreceivebin");
	);

	static GstStaticPadTemplate rtp_sink_template =
	GST_STATIC_PAD_TEMPLATE ("rtp_src",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS ("application/x-rtp"));

	static GstStaticPadTemplate rtcp_sink_template =
	GST_STATIC_PAD_TEMPLATE ("rtcp_src",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS ("application/x-rtp"));

	enum
	{
	PROP_0,
	PROP_STREAM,
	};

	static const gchar *
	_receive_state_to_string (ReceiveState state)
	{
	switch (state) {
	case RECEIVE_STATE_BLOCK:
	return "block";
	case RECEIVE_STATE_DROP:
	return "drop";
	case RECEIVE_STATE_PASS:
	return "pass";
	default:
	return "Unknown";
	}
	}

	static GstPadProbeReturn
	pad_block (GstPad * pad, GstPadProbeInfo * info, TransportReceiveBin * receive)
	{
	GstPadProbeReturn ret;

	g_mutex_lock (&receive->pad_block_lock);
	while (receive->receive_state == RECEIVE_STATE_BLOCK) {
	g_cond_wait (&receive->pad_block_cond, &receive->pad_block_lock);
	GST_DEBUG_OBJECT (pad, "probe waited. new state %s",
	_receive_state_to_string (receive->receive_state));
	}
	ret = GST_PAD_PROBE_PASS;

	if (receive->receive_state == RECEIVE_STATE_DROP) {
	ret = GST_PAD_PROBE_DROP;
	} else if (receive->receive_state == RECEIVE_STATE_PASS) {
	ret = GST_PAD_PROBE_OK;
	}

	g_mutex_unlock (&receive->pad_block_lock);

	return ret;
	}

	void
	transport_receive_bin_set_receive_state (TransportReceiveBin * receive,
	ReceiveState state)
	{
	g_mutex_lock (&receive->pad_block_lock);
	receive->receive_state = state;
	GST_DEBUG_OBJECT (receive, "changing receive state to %s",
	_receive_state_to_string (state));
	g_cond_signal (&receive->pad_block_cond);
	g_mutex_unlock (&receive->pad_block_lock);
	}

	static void
	transport_receive_bin_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec)
	{
	TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

	GST_OBJECT_LOCK (receive);
	switch (prop_id) {
	case PROP_STREAM:
	/* XXX: weak-ref this? */
	receive->stream = TRANSPORT_STREAM (g_value_get_object (value));
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	GST_OBJECT_UNLOCK (receive);
	}

	static void
	transport_receive_bin_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec)
	{
	TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

	GST_OBJECT_LOCK (receive);
	switch (prop_id) {
	case PROP_STREAM:
	g_value_set_object (value, receive->stream);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	GST_OBJECT_UNLOCK (receive);
	}

	static void
	transport_receive_bin_finalize (GObject * object)
	{
	TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);

	g_mutex_clear (&receive->pad_block_lock);
	g_cond_clear (&receive->pad_block_cond);

	G_OBJECT_CLASS (parent_class)->finalize (object);
	}

	static GstStateChangeReturn
	transport_receive_bin_change_state (GstElement * element,
	GstStateChange transition)
	{
	TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (element);
	GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

	GST_DEBUG ("changing state: %s => %s",
	gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
	gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));

	switch (transition) {
	case GST_STATE_CHANGE_NULL_TO_READY:{
	GstElement *elem;

	receive->rtp_block =
	_create_pad_block (GST_ELEMENT (receive), receive->rtp_src, 0, NULL,
	NULL);
	receive->rtp_block->block_id =
	gst_pad_add_probe (receive->rtp_src, GST_PAD_PROBE_TYPE_ALL_BOTH,
	(GstPadProbeCallback) pad_block, receive, NULL);

	/* XXX: because nice needs the nicesrc internal main loop running in order
	* correctly STUN... */
	/* FIXME: this races with the pad exposure later and may get not-linked */
	elem = receive->stream->transport->transport->src;
	gst_element_set_locked_state (elem, TRUE);
	gst_element_set_state (elem, GST_STATE_PLAYING);
	elem = receive->stream->rtcp_transport->transport->src;
	gst_element_set_locked_state (elem, TRUE);
	gst_element_set_state (elem, GST_STATE_PLAYING);
	break;
	}
	default:
	break;
	}

	ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
	if (ret == GST_STATE_CHANGE_FAILURE)
	return ret;

	switch (transition) {
	case GST_STATE_CHANGE_READY_TO_NULL:{
	GstElement *elem;

	elem = receive->stream->transport->transport->src;
	gst_element_set_locked_state (elem, FALSE);
	gst_element_set_state (elem, GST_STATE_NULL);
	elem = receive->stream->rtcp_transport->transport->src;
	gst_element_set_locked_state (elem, FALSE);
	gst_element_set_state (elem, GST_STATE_NULL);

	if (receive->rtp_block)
	_free_pad_block (receive->rtp_block);
	receive->rtp_block = NULL;
	break;
	}
	default:
	break;
	}

	return ret;
	}

	static void
	rtp_queue_overrun (GstElement * queue, TransportReceiveBin * receive)
	{
	GST_WARNING_OBJECT (receive, "Internal receive queue overrun. Dropping data");
	}

	static void
	transport_receive_bin_constructed (GObject * object)
	{
	TransportReceiveBin *receive = TRANSPORT_RECEIVE_BIN (object);
	GstWebRTCDTLSTransport *transport;
	GstPad ghost, pad;
	GstElement capsfilter, funnel, *queue;
	GstCaps *caps;

	g_return_if_fail (receive->stream);

	/* link ice src, dtlsrtp together for rtp */
	transport = receive->stream->transport;
	gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->dtlssrtpdec));

	capsfilter = gst_element_factory_make ("capsfilter", NULL);
	caps = gst_caps_new_empty_simple ("application/x-rtp");
	g_object_set (capsfilter, "caps", caps, NULL);
	gst_caps_unref (caps);

	gst_bin_add (GST_BIN (receive), GST_ELEMENT (capsfilter));
	if (!gst_element_link_pads (capsfilter, "src", transport->dtlssrtpdec,
	"sink"))
	g_warn_if_reached ();

	gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->transport->src));

	if (!gst_element_link_pads (GST_ELEMENT (transport->transport->src), "src",
	GST_ELEMENT (capsfilter), "sink"))
	g_warn_if_reached ();

	/* link ice src, dtlsrtp together for rtcp */
	transport = receive->stream->rtcp_transport;
	gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->dtlssrtpdec));

	capsfilter = gst_element_factory_make ("capsfilter", NULL);
	caps = gst_caps_new_empty_simple ("application/x-rtcp");
	g_object_set (capsfilter, "caps", caps, NULL);
	gst_caps_unref (caps);

	gst_bin_add (GST_BIN (receive), GST_ELEMENT (capsfilter));
	if (!gst_element_link_pads (capsfilter, "src", transport->dtlssrtpdec,
	"sink"))
	g_warn_if_reached ();

	gst_bin_add (GST_BIN (receive), GST_ELEMENT (transport->transport->src));

	if (!gst_element_link_pads (GST_ELEMENT (transport->transport->src), "src",
	GST_ELEMENT (capsfilter), "sink"))
	g_warn_if_reached ();

	/* create funnel for rtp_src */
	funnel = gst_element_factory_make ("funnel", NULL);
	gst_bin_add (GST_BIN (receive), funnel);
	if (!gst_element_link_pads (receive->stream->transport->dtlssrtpdec,
	"rtp_src", funnel, "sink_0"))
	g_warn_if_reached ();
	if (!gst_element_link_pads (receive->stream->rtcp_transport->dtlssrtpdec,
	"rtp_src", funnel, "sink_1"))
	g_warn_if_reached ();

	queue = gst_element_factory_make ("queue", NULL);
	/* FIXME: make this configurable? */
	g_object_set (queue, "leaky", 2, "max-size-time", (guint64) 0,
	"max-size-buffers", 0, "max-size-bytes", 5 * 1024 * 1024, NULL);
	g_signal_connect (queue, "overrun", G_CALLBACK (rtp_queue_overrun), receive);
	gst_bin_add (GST_BIN (receive), queue);
	if (!gst_element_link_pads (funnel, "src", queue, "sink"))
	g_warn_if_reached ();

	pad = gst_element_get_static_pad (queue, "src");
	receive->rtp_src = gst_ghost_pad_new ("rtp_src", pad);

	gst_element_add_pad (GST_ELEMENT (receive), receive->rtp_src);
	gst_object_unref (pad);

	/* create funnel for rtcp_src */
	funnel = gst_element_factory_make ("funnel", NULL);
	gst_bin_add (GST_BIN (receive), funnel);
	if (!gst_element_link_pads (receive->stream->transport->dtlssrtpdec,
	"rtcp_src", funnel, "sink_0"))
	g_warn_if_reached ();
	if (!gst_element_link_pads (receive->stream->rtcp_transport->dtlssrtpdec,
	"rtcp_src", funnel, "sink_1"))
	g_warn_if_reached ();

	pad = gst_element_get_static_pad (funnel, "src");
	ghost = gst_ghost_pad_new ("rtcp_src", pad);
	gst_element_add_pad (GST_ELEMENT (receive), ghost);
	gst_object_unref (pad);

	G_OBJECT_CLASS (parent_class)->constructed (object);
	}

	static void
	transport_receive_bin_class_init (TransportReceiveBinClass * klass)
	{
	GObjectClass gobject_class = (GObjectClass ) klass;
	GstElementClass element_class = (GstElementClass ) klass;

	element_class->change_state = transport_receive_bin_change_state;

	gst_element_class_add_static_pad_template (element_class, &rtp_sink_template);
	gst_element_class_add_static_pad_template (element_class,
	&rtcp_sink_template);

	gst_element_class_set_metadata (element_class, "WebRTC Transport Receive Bin",
	"Filter/Network/WebRTC", "A bin for webrtc connections",
	"Matthew Waters <matthew@centricular.com>");

	gobject_class->constructed = transport_receive_bin_constructed;
	gobject_class->get_property = transport_receive_bin_get_property;
	gobject_class->set_property = transport_receive_bin_set_property;
	gobject_class->finalize = transport_receive_bin_finalize;

	g_object_class_install_property (gobject_class,
	PROP_STREAM,
	g_param_spec_object ("stream", "Stream",
	"The TransportStream for this receiveing bin",
	transport_stream_get_type (),
	G_PARAM_READWRITE \| G_PARAM_CONSTRUCT_ONLY \| G_PARAM_STATIC_STRINGS));
	}

	static void
	transport_receive_bin_init (TransportReceiveBin * receive)
	{
	g_mutex_init (&receive->pad_block_lock);
	g_cond_init (&receive->pad_block_cond);
	}