sys/bluez/gsta2dpsink.c - imx-gst-plugins-bad - Git at Google

 /*
  *
  *  BlueZ - Bluetooth protocol stack for Linux
  *
  *  Copyright (C) 2004-2010  Marcel Holtmann <marcel@holtmann.org>
  *
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2.1 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
  *  Lesser General Public License for more details.
  *
  *  You should have received a copy of the GNU Lesser 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 <unistd.h>

 #include "gsta2dpsink.h"

 #include <gst/rtp/gstrtpbasepayload.h>

 GST_DEBUG_CATEGORY_STATIC (gst_a2dp_sink_debug);
 #define GST_CAT_DEFAULT gst_a2dp_sink_debug

 #define A2DP_SBC_RTP_PAYLOAD_TYPE 1

 #define DEFAULT_AUTOCONNECT TRUE

 enum
 {
   PROP_0,
   PROP_DEVICE,
   PROP_AUTOCONNECT,
   PROP_TRANSPORT
 };

 #define parent_class gst_a2dp_sink_parent_class
 G_DEFINE_TYPE (GstA2dpSink, gst_a2dp_sink, GST_TYPE_BIN);

 static GstStaticPadTemplate gst_a2dp_sink_factory =
     GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
     GST_STATIC_CAPS ("audio/x-sbc, "
         "rate = (int) { 16000, 32000, 44100, 48000 }, "
         "channels = (int) [ 1, 2 ], "
         "channel-mode = (string) { mono, dual, stereo, joint }, "
         "blocks = (int) { 4, 8, 12, 16 }, "
         "subbands = (int) { 4, 8 }, "
         "allocation-method = (string) { snr, loudness }, "
         "bitpool = (int) [ 2, " TEMPLATE_MAX_BITPOOL_STR " ]; " "audio/mpeg"));

 static gboolean gst_a2dp_sink_handle_event (GstPad * pad,
     GstObject * pad_parent, GstEvent * event);
 static gboolean gst_a2dp_sink_query (GstPad * pad, GstObject * parent,
     GstQuery * query);
 static GstCaps *gst_a2dp_sink_get_caps (GstA2dpSink * self);

 /*
  * Helper function to create elements, add to the bin and link it
  * to another element.
  */
 static GstElement *
 gst_a2dp_sink_init_element (GstA2dpSink * self, const gchar * elementname,
     const gchar * name)
 {
   GstElement *element;
   GstPad *sinkpad;

   GST_LOG_OBJECT (self, "Initializing %s", elementname);

   element = gst_element_factory_make (elementname, name);
   if (element == NULL) {
     GST_DEBUG_OBJECT (self, "Couldn't create %s", elementname);
     return NULL;
   }

   if (!gst_bin_add (GST_BIN (self), element)) {
     GST_DEBUG_OBJECT (self, "failed to add %s to the bin", elementname);
     goto cleanup_and_fail;
   }

   sinkpad = gst_element_get_static_pad (element, "sink");
   if (!gst_ghost_pad_set_target (GST_GHOST_PAD (self->ghostpad), sinkpad)) {
     GST_ERROR_OBJECT (self, "Failed to set target for ghost pad");
     goto remove_element_and_fail;
   }

   if (!gst_element_sync_state_with_parent (element)) {
     GST_DEBUG_OBJECT (self, "%s failed to go to playing", elementname);
     goto remove_element_and_fail;
   }

   return element;

 remove_element_and_fail:
   gst_element_set_state (element, GST_STATE_NULL);
   gst_bin_remove (GST_BIN (self), element);
   return NULL;

 cleanup_and_fail:
   g_object_unref (G_OBJECT (element));

   return NULL;
 }

 static void
 gst_a2dp_sink_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
   GstA2dpSink *self = GST_A2DP_SINK (object);

   switch (prop_id) {
     case PROP_DEVICE:
       if (self->sink != NULL)
         gst_avdtp_sink_set_device (self->sink, g_value_get_string (value));

       g_free (self->device);
       self->device = g_value_dup_string (value);
       break;

     case PROP_TRANSPORT:
       if (self->sink != NULL)
         gst_avdtp_sink_set_transport (self->sink, g_value_get_string (value));

       g_free (self->transport);
       self->transport = g_value_dup_string (value);
       break;

     case PROP_AUTOCONNECT:
       self->autoconnect = g_value_get_boolean (value);

       if (self->sink != NULL)
         g_object_set (G_OBJECT (self->sink), "auto-connect",
             self->autoconnect, NULL);
       break;

     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static void
 gst_a2dp_sink_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
   GstA2dpSink *self = GST_A2DP_SINK (object);
   gchar *device, *transport;

   switch (prop_id) {
     case PROP_DEVICE:
       if (self->sink != NULL) {
         device = gst_avdtp_sink_get_device (self->sink);
         if (device != NULL)
           g_value_take_string (value, device);
       }
       break;
     case PROP_AUTOCONNECT:
       if (self->sink != NULL)
         g_object_get (G_OBJECT (self->sink), "auto-connect",
             &self->autoconnect, NULL);

       g_value_set_boolean (value, self->autoconnect);
       break;
     case PROP_TRANSPORT:
       if (self->sink != NULL) {
         transport = gst_avdtp_sink_get_transport (self->sink);
         if (transport != NULL)
           g_value_take_string (value, transport);
       }
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static gboolean
 gst_a2dp_sink_init_ghost_pad (GstA2dpSink * self)
 {
   GstPadTemplate *templ;

   /* now we add a ghostpad */
   templ = gst_static_pad_template_get (&gst_a2dp_sink_factory);
   self->ghostpad = gst_ghost_pad_new_no_target_from_template ("sink", templ);
   g_object_unref (templ);

   /* the getcaps of our ghostpad must reflect the device caps */
   gst_pad_set_query_function (self->ghostpad, gst_a2dp_sink_query);

   gst_pad_set_event_function (self->ghostpad, gst_a2dp_sink_handle_event);

   if (!gst_element_add_pad (GST_ELEMENT (self), self->ghostpad))
     GST_ERROR_OBJECT (self, "failed to add ghostpad");

   return TRUE;
 }

 static void
 gst_a2dp_sink_remove_dynamic_elements (GstA2dpSink * self)
 {
   if (self->rtp) {
     GST_LOG_OBJECT (self, "removing rtp element from the bin");
     if (!gst_bin_remove (GST_BIN (self), GST_ELEMENT (self->rtp)))
       GST_WARNING_OBJECT (self, "failed to remove rtp " "element from bin");
     else
       self->rtp = NULL;
   }
 }

 static GstStateChangeReturn
 gst_a2dp_sink_change_state (GstElement * element, GstStateChange transition)
 {
   GstStateChangeReturn ret;
   GstA2dpSink *self = GST_A2DP_SINK (element);

   switch (transition) {
     case GST_STATE_CHANGE_READY_TO_PAUSED:
       self->taglist = gst_tag_list_new_empty ();
       break;

     case GST_STATE_CHANGE_NULL_TO_READY:
       if (self->device != NULL)
         gst_avdtp_sink_set_device (self->sink, self->device);

       if (self->transport != NULL)
         gst_avdtp_sink_set_transport (self->sink, self->transport);

       g_object_set (G_OBJECT (self->sink), "auto-connect",
           self->autoconnect, NULL);

       break;

     default:
       break;
   }

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

   switch (transition) {
     case GST_STATE_CHANGE_PAUSED_TO_READY:
       if (self->taglist) {
         gst_tag_list_unref (self->taglist);
         self->taglist = NULL;
       }
       break;

     case GST_STATE_CHANGE_READY_TO_NULL:
       gst_a2dp_sink_remove_dynamic_elements (self);

       break;
     default:
       break;
   }

   return ret;
 }

 static void
 gst_a2dp_sink_class_init (GstA2dpSinkClass * klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
   GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

   parent_class = g_type_class_peek_parent (klass);

   object_class->set_property = GST_DEBUG_FUNCPTR (gst_a2dp_sink_set_property);
   object_class->get_property = GST_DEBUG_FUNCPTR (gst_a2dp_sink_get_property);

   element_class->change_state = GST_DEBUG_FUNCPTR (gst_a2dp_sink_change_state);

   g_object_class_install_property (object_class, PROP_DEVICE,
       g_param_spec_string ("device", "Device",
           "Bluetooth remote device address", NULL, G_PARAM_READWRITE));

   g_object_class_install_property (object_class, PROP_AUTOCONNECT,
       g_param_spec_boolean ("auto-connect", "Auto-connect",
           "Automatically attempt to connect to device",
           DEFAULT_AUTOCONNECT, G_PARAM_READWRITE));

   g_object_class_install_property (object_class, PROP_TRANSPORT,
       g_param_spec_string ("transport", "Transport",
           "Use configured transport", NULL, G_PARAM_READWRITE));

   gst_element_class_set_static_metadata (element_class, "Bluetooth A2DP sink",
       "Sink/Audio", "Plays audio to an A2DP device",
       "Marcel Holtmann <marcel@holtmann.org>");

   GST_DEBUG_CATEGORY_INIT (gst_a2dp_sink_debug, "a2dpsink", 0,
       "A2DP sink element");

   gst_element_class_add_static_pad_template (element_class,
       &gst_a2dp_sink_factory);
 }

 GstCaps *
 gst_a2dp_sink_get_device_caps (GstA2dpSink * self)
 {
   return gst_avdtp_sink_get_device_caps (self->sink);
 }

 static GstCaps *
 gst_a2dp_sink_get_caps (GstA2dpSink * self)
 {
   GstCaps *caps = NULL;

   if (self->sink != NULL) {
     GST_LOG_OBJECT (self, "Getting device caps");
     caps = gst_a2dp_sink_get_device_caps (self);
   }

   if (!caps)
     caps = gst_static_pad_template_get_caps (&gst_a2dp_sink_factory);

   return caps;
 }

 static gboolean
 gst_a2dp_sink_init_avdtp_sink (GstA2dpSink * self)
 {
   GstElement *sink;

   if (self->sink == NULL)
     sink = gst_element_factory_make ("avdtpsink", "avdtpsink");
   else
     sink = GST_ELEMENT (self->sink);

   if (sink == NULL) {
     GST_ERROR_OBJECT (self, "Couldn't create avdtpsink");
     return FALSE;
   }

   if (!gst_bin_add (GST_BIN (self), sink)) {
     GST_ERROR_OBJECT (self, "failed to add avdtpsink " "to the bin");
     goto cleanup_and_fail;
   }

   self->sink = GST_AVDTP_SINK (sink);
   g_object_set (G_OBJECT (self->sink), "device", self->device, NULL);
   g_object_set (G_OBJECT (self->sink), "transport", self->transport, NULL);

   gst_element_sync_state_with_parent (sink);

   return TRUE;

 cleanup_and_fail:
   if (sink != NULL)
     g_object_unref (G_OBJECT (sink));

   return FALSE;
 }

 static gboolean
 gst_a2dp_sink_init_rtp_sbc_element (GstA2dpSink * self)
 {
   GstElement *rtppay;

   /* if we already have a rtp, we don't need a new one */
   if (self->rtp != NULL)
     return TRUE;

   rtppay = gst_a2dp_sink_init_element (self, "rtpsbcpay", "rtp");
   if (rtppay == NULL)
     return FALSE;

   self->rtp = rtppay;
   g_object_set (self->rtp, "min-frames", -1, NULL);

   gst_element_set_state (rtppay, GST_STATE_PAUSED);

   return TRUE;
 }

 static gboolean
 gst_a2dp_sink_init_rtp_mpeg_element (GstA2dpSink * self)
 {
   GstElement *rtppay;

   /* check if we don't need a new rtp */
   if (self->rtp)
     return TRUE;

   GST_LOG_OBJECT (self, "Initializing rtp mpeg element");

   rtppay = gst_a2dp_sink_init_element (self, "rtpmpapay", "rtp");
   if (rtppay == NULL)
     return FALSE;

   self->rtp = rtppay;

   gst_element_set_state (rtppay, GST_STATE_PAUSED);

   return TRUE;
 }

 static gboolean
 gst_a2dp_sink_init_dynamic_elements (GstA2dpSink * self, GstCaps * caps)
 {
   GstStructure *structure;
   GstEvent *event;
   gboolean crc;
   gchar *mode = NULL;

   structure = gst_caps_get_structure (caps, 0);

   /* first, we need to create our rtp payloader */
   if (gst_structure_has_name (structure, "audio/x-sbc")) {
     GST_LOG_OBJECT (self, "sbc media received");
     if (!gst_a2dp_sink_init_rtp_sbc_element (self))
       return FALSE;
   } else if (gst_structure_has_name (structure, "audio/mpeg")) {
     GST_LOG_OBJECT (self, "mp3 media received");
     if (!gst_a2dp_sink_init_rtp_mpeg_element (self))
       return FALSE;
   } else {
     GST_ERROR_OBJECT (self, "Unexpected media type");
     return FALSE;
   }

   if (!gst_element_link (GST_ELEMENT (self->rtp), GST_ELEMENT (self->sink))) {
     GST_ERROR_OBJECT (self, "couldn't link rtpsbcpay " "to avdtpsink");
     return FALSE;
   }

   /* check if we should push the taglist FIXME should we push this?
    * we can send the tags directly if needed */
   if (self->taglist != NULL && gst_structure_has_name (structure, "audio/mpeg")) {

     event = gst_event_new_tag (self->taglist);

     /* send directly the crc */
     if (gst_tag_list_get_boolean (self->taglist, "has-crc", &crc))
       gst_avdtp_sink_set_crc (self->sink, crc);

     if (gst_tag_list_get_string (self->taglist, "channel-mode", &mode))
       gst_avdtp_sink_set_channel_mode (self->sink, mode);

     gst_pad_send_event (self->ghostpad, event);

     self->taglist = NULL;
     g_free (mode);
   }

   g_object_set (self->rtp, "mtu",
       gst_avdtp_sink_get_link_mtu (self->sink), NULL);

   return TRUE;
 }

 static gboolean
 gst_a2dp_sink_handle_event (GstPad * pad, GstObject * pad_parent,
     GstEvent * event)
 {
   GstA2dpSink *self;
   GstTagList *taglist = NULL;

   self = GST_A2DP_SINK (pad_parent);

   if (GST_EVENT_TYPE (event) == GST_EVENT_TAG) {
     if (self->taglist == NULL)
       gst_event_parse_tag (event, &self->taglist);
     else {
       gst_event_parse_tag (event, &taglist);
       gst_tag_list_insert (self->taglist, taglist, GST_TAG_MERGE_REPLACE);
     }
   } else if (GST_EVENT_TYPE (event) == GST_EVENT_CAPS) {
     GstCaps *caps = NULL;

     gst_event_parse_caps (event, &caps);
     gst_a2dp_sink_init_dynamic_elements (self, caps);
   }

   return gst_pad_event_default (pad, pad_parent, event);
 }

 static gboolean
 gst_a2dp_sink_query (GstPad * pad, GstObject * parent, GstQuery * query)
 {
   GstA2dpSink *sink = GST_A2DP_SINK (parent);
   gboolean ret;

   if (GST_QUERY_TYPE (query) == GST_QUERY_CAPS) {
     GstCaps *caps;

     caps = gst_a2dp_sink_get_caps (sink);
     gst_query_set_caps_result (query, caps);
     gst_caps_unref (caps);
     ret = TRUE;
   } else {
     ret = gst_pad_query_default (pad, parent, query);
   }

   return ret;
 }

 static void
 gst_a2dp_sink_init (GstA2dpSink * self)
 {
   self->sink = NULL;
   self->rtp = NULL;
   self->device = NULL;
   self->transport = NULL;
   self->autoconnect = DEFAULT_AUTOCONNECT;
   self->taglist = NULL;
   self->ghostpad = NULL;

   gst_a2dp_sink_init_ghost_pad (self);

   gst_a2dp_sink_init_avdtp_sink (self);
 }
	/*
	*
	* BlueZ - Bluetooth protocol stack for Linux
	*
	* Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org>
	*
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser 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 <unistd.h>

	#include "gsta2dpsink.h"

	#include <gst/rtp/gstrtpbasepayload.h>

	GST_DEBUG_CATEGORY_STATIC (gst_a2dp_sink_debug);
	#define GST_CAT_DEFAULT gst_a2dp_sink_debug

	#define A2DP_SBC_RTP_PAYLOAD_TYPE 1

	#define DEFAULT_AUTOCONNECT TRUE

	enum
	{
	PROP_0,
	PROP_DEVICE,
	PROP_AUTOCONNECT,
	PROP_TRANSPORT
	};

	#define parent_class gst_a2dp_sink_parent_class
	G_DEFINE_TYPE (GstA2dpSink, gst_a2dp_sink, GST_TYPE_BIN);

	static GstStaticPadTemplate gst_a2dp_sink_factory =
	GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
	GST_STATIC_CAPS ("audio/x-sbc, "
	"rate = (int) { 16000, 32000, 44100, 48000 }, "
	"channels = (int) [ 1, 2 ], "
	"channel-mode = (string) { mono, dual, stereo, joint }, "
	"blocks = (int) { 4, 8, 12, 16 }, "
	"subbands = (int) { 4, 8 }, "
	"allocation-method = (string) { snr, loudness }, "
	"bitpool = (int) [ 2, " TEMPLATE_MAX_BITPOOL_STR " ]; " "audio/mpeg"));

	static gboolean gst_a2dp_sink_handle_event (GstPad * pad,
	GstObject * pad_parent, GstEvent * event);
	static gboolean gst_a2dp_sink_query (GstPad * pad, GstObject * parent,
	GstQuery * query);
	static GstCaps gst_a2dp_sink_get_caps (GstA2dpSink self);

	/*
	* Helper function to create elements, add to the bin and link it
	* to another element.
	*/
	static GstElement *
	gst_a2dp_sink_init_element (GstA2dpSink * self, const gchar * elementname,
	const gchar * name)
	{
	GstElement *element;
	GstPad *sinkpad;

	GST_LOG_OBJECT (self, "Initializing %s", elementname);

	element = gst_element_factory_make (elementname, name);
	if (element == NULL) {
	GST_DEBUG_OBJECT (self, "Couldn't create %s", elementname);
	return NULL;
	}

	if (!gst_bin_add (GST_BIN (self), element)) {
	GST_DEBUG_OBJECT (self, "failed to add %s to the bin", elementname);
	goto cleanup_and_fail;
	}

	sinkpad = gst_element_get_static_pad (element, "sink");
	if (!gst_ghost_pad_set_target (GST_GHOST_PAD (self->ghostpad), sinkpad)) {
	GST_ERROR_OBJECT (self, "Failed to set target for ghost pad");
	goto remove_element_and_fail;
	}

	if (!gst_element_sync_state_with_parent (element)) {
	GST_DEBUG_OBJECT (self, "%s failed to go to playing", elementname);
	goto remove_element_and_fail;
	}

	return element;

	remove_element_and_fail:
	gst_element_set_state (element, GST_STATE_NULL);
	gst_bin_remove (GST_BIN (self), element);
	return NULL;

	cleanup_and_fail:
	g_object_unref (G_OBJECT (element));

	return NULL;
	}

	static void
	gst_a2dp_sink_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec)
	{
	GstA2dpSink *self = GST_A2DP_SINK (object);

	switch (prop_id) {
	case PROP_DEVICE:
	if (self->sink != NULL)
	gst_avdtp_sink_set_device (self->sink, g_value_get_string (value));

	g_free (self->device);
	self->device = g_value_dup_string (value);
	break;

	case PROP_TRANSPORT:
	if (self->sink != NULL)
	gst_avdtp_sink_set_transport (self->sink, g_value_get_string (value));

	g_free (self->transport);
	self->transport = g_value_dup_string (value);
	break;

	case PROP_AUTOCONNECT:
	self->autoconnect = g_value_get_boolean (value);

	if (self->sink != NULL)
	g_object_set (G_OBJECT (self->sink), "auto-connect",
	self->autoconnect, NULL);
	break;

	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static void
	gst_a2dp_sink_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec)
	{
	GstA2dpSink *self = GST_A2DP_SINK (object);
	gchar device, transport;

	switch (prop_id) {
	case PROP_DEVICE:
	if (self->sink != NULL) {
	device = gst_avdtp_sink_get_device (self->sink);
	if (device != NULL)
	g_value_take_string (value, device);
	}
	break;
	case PROP_AUTOCONNECT:
	if (self->sink != NULL)
	g_object_get (G_OBJECT (self->sink), "auto-connect",
	&self->autoconnect, NULL);

	g_value_set_boolean (value, self->autoconnect);
	break;
	case PROP_TRANSPORT:
	if (self->sink != NULL) {
	transport = gst_avdtp_sink_get_transport (self->sink);
	if (transport != NULL)
	g_value_take_string (value, transport);
	}
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static gboolean
	gst_a2dp_sink_init_ghost_pad (GstA2dpSink * self)
	{
	GstPadTemplate *templ;

	/* now we add a ghostpad */
	templ = gst_static_pad_template_get (&gst_a2dp_sink_factory);
	self->ghostpad = gst_ghost_pad_new_no_target_from_template ("sink", templ);
	g_object_unref (templ);

	/* the getcaps of our ghostpad must reflect the device caps */
	gst_pad_set_query_function (self->ghostpad, gst_a2dp_sink_query);

	gst_pad_set_event_function (self->ghostpad, gst_a2dp_sink_handle_event);

	if (!gst_element_add_pad (GST_ELEMENT (self), self->ghostpad))
	GST_ERROR_OBJECT (self, "failed to add ghostpad");

	return TRUE;
	}

	static void
	gst_a2dp_sink_remove_dynamic_elements (GstA2dpSink * self)
	{
	if (self->rtp) {
	GST_LOG_OBJECT (self, "removing rtp element from the bin");
	if (!gst_bin_remove (GST_BIN (self), GST_ELEMENT (self->rtp)))
	GST_WARNING_OBJECT (self, "failed to remove rtp " "element from bin");
	else
	self->rtp = NULL;
	}
	}

	static GstStateChangeReturn
	gst_a2dp_sink_change_state (GstElement * element, GstStateChange transition)
	{
	GstStateChangeReturn ret;
	GstA2dpSink *self = GST_A2DP_SINK (element);

	switch (transition) {
	case GST_STATE_CHANGE_READY_TO_PAUSED:
	self->taglist = gst_tag_list_new_empty ();
	break;

	case GST_STATE_CHANGE_NULL_TO_READY:
	if (self->device != NULL)
	gst_avdtp_sink_set_device (self->sink, self->device);

	if (self->transport != NULL)
	gst_avdtp_sink_set_transport (self->sink, self->transport);

	g_object_set (G_OBJECT (self->sink), "auto-connect",
	self->autoconnect, NULL);

	break;

	default:
	break;
	}

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

	switch (transition) {
	case GST_STATE_CHANGE_PAUSED_TO_READY:
	if (self->taglist) {
	gst_tag_list_unref (self->taglist);
	self->taglist = NULL;
	}
	break;

	case GST_STATE_CHANGE_READY_TO_NULL:
	gst_a2dp_sink_remove_dynamic_elements (self);

	break;
	default:
	break;
	}

	return ret;
	}

	static void
	gst_a2dp_sink_class_init (GstA2dpSinkClass * klass)
	{
	GObjectClass *object_class = G_OBJECT_CLASS (klass);
	GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

	parent_class = g_type_class_peek_parent (klass);

	object_class->set_property = GST_DEBUG_FUNCPTR (gst_a2dp_sink_set_property);
	object_class->get_property = GST_DEBUG_FUNCPTR (gst_a2dp_sink_get_property);

	element_class->change_state = GST_DEBUG_FUNCPTR (gst_a2dp_sink_change_state);

	g_object_class_install_property (object_class, PROP_DEVICE,
	g_param_spec_string ("device", "Device",
	"Bluetooth remote device address", NULL, G_PARAM_READWRITE));

	g_object_class_install_property (object_class, PROP_AUTOCONNECT,
	g_param_spec_boolean ("auto-connect", "Auto-connect",
	"Automatically attempt to connect to device",
	DEFAULT_AUTOCONNECT, G_PARAM_READWRITE));

	g_object_class_install_property (object_class, PROP_TRANSPORT,
	g_param_spec_string ("transport", "Transport",
	"Use configured transport", NULL, G_PARAM_READWRITE));

	gst_element_class_set_static_metadata (element_class, "Bluetooth A2DP sink",
	"Sink/Audio", "Plays audio to an A2DP device",
	"Marcel Holtmann <marcel@holtmann.org>");

	GST_DEBUG_CATEGORY_INIT (gst_a2dp_sink_debug, "a2dpsink", 0,
	"A2DP sink element");

	gst_element_class_add_static_pad_template (element_class,
	&gst_a2dp_sink_factory);
	}

	GstCaps *
	gst_a2dp_sink_get_device_caps (GstA2dpSink * self)
	{
	return gst_avdtp_sink_get_device_caps (self->sink);
	}

	static GstCaps *
	gst_a2dp_sink_get_caps (GstA2dpSink * self)
	{
	GstCaps *caps = NULL;

	if (self->sink != NULL) {
	GST_LOG_OBJECT (self, "Getting device caps");
	caps = gst_a2dp_sink_get_device_caps (self);
	}

	if (!caps)
	caps = gst_static_pad_template_get_caps (&gst_a2dp_sink_factory);

	return caps;
	}

	static gboolean
	gst_a2dp_sink_init_avdtp_sink (GstA2dpSink * self)
	{
	GstElement *sink;

	if (self->sink == NULL)
	sink = gst_element_factory_make ("avdtpsink", "avdtpsink");
	else
	sink = GST_ELEMENT (self->sink);

	if (sink == NULL) {
	GST_ERROR_OBJECT (self, "Couldn't create avdtpsink");
	return FALSE;
	}

	if (!gst_bin_add (GST_BIN (self), sink)) {
	GST_ERROR_OBJECT (self, "failed to add avdtpsink " "to the bin");
	goto cleanup_and_fail;
	}

	self->sink = GST_AVDTP_SINK (sink);
	g_object_set (G_OBJECT (self->sink), "device", self->device, NULL);
	g_object_set (G_OBJECT (self->sink), "transport", self->transport, NULL);

	gst_element_sync_state_with_parent (sink);

	return TRUE;

	cleanup_and_fail:
	if (sink != NULL)
	g_object_unref (G_OBJECT (sink));

	return FALSE;
	}

	static gboolean
	gst_a2dp_sink_init_rtp_sbc_element (GstA2dpSink * self)
	{
	GstElement *rtppay;

	/* if we already have a rtp, we don't need a new one */
	if (self->rtp != NULL)
	return TRUE;

	rtppay = gst_a2dp_sink_init_element (self, "rtpsbcpay", "rtp");
	if (rtppay == NULL)
	return FALSE;

	self->rtp = rtppay;
	g_object_set (self->rtp, "min-frames", -1, NULL);

	gst_element_set_state (rtppay, GST_STATE_PAUSED);

	return TRUE;
	}

	static gboolean
	gst_a2dp_sink_init_rtp_mpeg_element (GstA2dpSink * self)
	{
	GstElement *rtppay;

	/* check if we don't need a new rtp */
	if (self->rtp)
	return TRUE;

	GST_LOG_OBJECT (self, "Initializing rtp mpeg element");

	rtppay = gst_a2dp_sink_init_element (self, "rtpmpapay", "rtp");
	if (rtppay == NULL)
	return FALSE;

	self->rtp = rtppay;

	gst_element_set_state (rtppay, GST_STATE_PAUSED);

	return TRUE;
	}

	static gboolean
	gst_a2dp_sink_init_dynamic_elements (GstA2dpSink * self, GstCaps * caps)
	{
	GstStructure *structure;
	GstEvent *event;
	gboolean crc;
	gchar *mode = NULL;

	structure = gst_caps_get_structure (caps, 0);

	/* first, we need to create our rtp payloader */
	if (gst_structure_has_name (structure, "audio/x-sbc")) {
	GST_LOG_OBJECT (self, "sbc media received");
	if (!gst_a2dp_sink_init_rtp_sbc_element (self))
	return FALSE;
	} else if (gst_structure_has_name (structure, "audio/mpeg")) {
	GST_LOG_OBJECT (self, "mp3 media received");
	if (!gst_a2dp_sink_init_rtp_mpeg_element (self))
	return FALSE;
	} else {
	GST_ERROR_OBJECT (self, "Unexpected media type");
	return FALSE;
	}

	if (!gst_element_link (GST_ELEMENT (self->rtp), GST_ELEMENT (self->sink))) {
	GST_ERROR_OBJECT (self, "couldn't link rtpsbcpay " "to avdtpsink");
	return FALSE;
	}

	/* check if we should push the taglist FIXME should we push this?
	* we can send the tags directly if needed */
	if (self->taglist != NULL && gst_structure_has_name (structure, "audio/mpeg")) {

	event = gst_event_new_tag (self->taglist);

	/* send directly the crc */
	if (gst_tag_list_get_boolean (self->taglist, "has-crc", &crc))
	gst_avdtp_sink_set_crc (self->sink, crc);

	if (gst_tag_list_get_string (self->taglist, "channel-mode", &mode))
	gst_avdtp_sink_set_channel_mode (self->sink, mode);

	gst_pad_send_event (self->ghostpad, event);

	self->taglist = NULL;
	g_free (mode);
	}

	g_object_set (self->rtp, "mtu",
	gst_avdtp_sink_get_link_mtu (self->sink), NULL);

	return TRUE;
	}

	static gboolean
	gst_a2dp_sink_handle_event (GstPad * pad, GstObject * pad_parent,
	GstEvent * event)
	{
	GstA2dpSink *self;
	GstTagList *taglist = NULL;

	self = GST_A2DP_SINK (pad_parent);

	if (GST_EVENT_TYPE (event) == GST_EVENT_TAG) {
	if (self->taglist == NULL)
	gst_event_parse_tag (event, &self->taglist);
	else {
	gst_event_parse_tag (event, &taglist);
	gst_tag_list_insert (self->taglist, taglist, GST_TAG_MERGE_REPLACE);
	}
	} else if (GST_EVENT_TYPE (event) == GST_EVENT_CAPS) {
	GstCaps *caps = NULL;

	gst_event_parse_caps (event, &caps);
	gst_a2dp_sink_init_dynamic_elements (self, caps);
	}

	return gst_pad_event_default (pad, pad_parent, event);
	}

	static gboolean
	gst_a2dp_sink_query (GstPad * pad, GstObject * parent, GstQuery * query)
	{
	GstA2dpSink *sink = GST_A2DP_SINK (parent);
	gboolean ret;

	if (GST_QUERY_TYPE (query) == GST_QUERY_CAPS) {
	GstCaps *caps;

	caps = gst_a2dp_sink_get_caps (sink);
	gst_query_set_caps_result (query, caps);
	gst_caps_unref (caps);
	ret = TRUE;
	} else {
	ret = gst_pad_query_default (pad, parent, query);
	}

	return ret;
	}

	static void
	gst_a2dp_sink_init (GstA2dpSink * self)
	{
	self->sink = NULL;
	self->rtp = NULL;
	self->device = NULL;
	self->transport = NULL;
	self->autoconnect = DEFAULT_AUTOCONNECT;
	self->taglist = NULL;
	self->ghostpad = NULL;

	gst_a2dp_sink_init_ghost_pad (self);

	gst_a2dp_sink_init_avdtp_sink (self);
	}