diff -r 000000000000 -r 0e761a78d257 gstreamer_core/gst/gstbin.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/gst/gstbin.c	Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,3497 @@
+/* GStreamer
+ *
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2004 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * gstbin.c: GstBin container object and support code
+ *
+ * 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * MT safe.
+ */
+
+/**
+ * SECTION:gstbin
+ * @short_description: Base class and element that can contain other elements
+ *
+ * #GstBin is an element that can contain other #GstElement, allowing them to be
+ * managed as a group.
+ * Pads from the child elements can be ghosted to the bin, see #GstGhostPad.
+ * This makes the bin look like any other elements and enables creation of
+ * higher-level abstraction elements.
+ *
+ * A new #GstBin is created with gst_bin_new(). Use a #GstPipeline instead if you
+ * want to create a toplevel bin because a normal bin doesn't have a bus or
+ * handle clock distribution of its own.
+ *
+ * After the bin has been created you will typically add elements to it with
+ * gst_bin_add(). You can remove elements with gst_bin_remove().
+ *
+ * An element can be retrieved from a bin with gst_bin_get_by_name(), using the
+ * elements name. gst_bin_get_by_name_recurse_up() is mainly used for internal
+ * purposes and will query the parent bins when the element is not found in the
+ * current bin.
+ *
+ * An iterator of elements in a bin can be retrieved with
+ * gst_bin_iterate_elements(). Various other iterators exist to retrieve the
+ * elements in a bin.
+ *
+ * gst_object_unref() is used to drop your reference to the bin.
+ *
+ * The <link linkend="GstBin-element-added">element-added</link> signal is
+ * fired whenever a new element is added to the bin. Likewise the <link
+ * linkend="GstBin-element-removed">element-removed</link> signal is fired
+ * whenever an element is removed from the bin.
+ *
+ * <refsect2><title>Notes</title>
+ * <para>
+ * A #GstBin internally intercepts every #GstMessage posted by its children and
+ * implements the following default behaviour for each of them:
+ * <variablelist>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_EOS</term>
+ *     <listitem><para>This message is only posted by sinks in the PLAYING
+ *     state. If all sinks posted the EOS message, this bin will post and EOS
+ *     message upwards.</para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_SEGMENT_START</term>
+ *     <listitem><para>just collected and never forwarded upwards.
+ *     The messages are used to decide when all elements have completed playback
+ *     of their segment.</para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_SEGMENT_DONE</term>
+ *     <listitem><para> Is posted by #GstBin when all elements that posted
+ *     a SEGMENT_START have posted a SEGMENT_DONE.</para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_DURATION</term>
+ *     <listitem><para> Is posted by an element that detected a change
+ *     in the stream duration. The default bin behaviour is to clear any
+ *     cached duration values so that the next duration query will perform
+ *     a full duration recalculation. The duration change is posted to the
+ *     application so that it can refetch the new duration with a duration
+ *     query.
+ *     </para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_CLOCK_LOST</term>
+ *     <listitem><para> This message is posted by an element when it
+ *     can no longer provide a clock. The default bin behaviour is to
+ *     check if the lost clock was the one provided by the bin. If so and
+ *     the bin is currently in the PLAYING state, the message is forwarded to
+ *     the bin parent.
+ *     This message is also generated when a clock provider is removed from
+ *     the bin. If this message is received by the application, it should
+ *     PAUSE the pipeline and set it back to PLAYING to force a new clock
+ *     distribution.
+ *     </para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_MESSAGE_CLOCK_PROVIDE</term>
+ *     <listitem><para> This message is generated when an element
+ *     can provide a clock. This mostly happens when a new clock
+ *     provider is added to the bin. The default behaviour of the bin is to
+ *     mark the currently selected clock as dirty, which will perform a clock
+ *     recalculation the next time the bin is asked to provide a clock.
+ *     This message is never sent tot the application but is forwarded to
+ *     the parent of the bin.
+ *     </para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>OTHERS</term>
+ *     <listitem><para> posted upwards.</para></listitem>
+ *   </varlistentry>
+ * </variablelist>
+ *
+ *
+ * A #GstBin implements the following default behaviour for answering to a
+ * #GstQuery:
+ * <variablelist>
+ *   <varlistentry>
+ *     <term>GST_QUERY_DURATION</term>
+ *     <listitem><para>If the query has been asked before with the same format
+ *     and the bin is a toplevel bin (ie. has no parent),
+ *     use the cached previous value. If no previous value was cached, the
+ *     query is sent to all sink elements in the bin and the MAXIMUM of all
+ *     values is returned. If the bin is a toplevel bin the value is cached.
+ *     If no sinks are available in the bin, the query fails.
+ *     </para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>GST_QUERY_POSITION</term>
+ *     <listitem><para>The query is sent to all sink elements in the bin and the
+ *     MAXIMUM of all values is returned. If no sinks are available in the bin,
+ *     the query fails.
+ *     </para></listitem>
+ *   </varlistentry>
+ *   <varlistentry>
+ *     <term>OTHERS</term>
+ *     <listitem><para>the query is forwarded to all sink elements, the result
+ *     of the first sink that answers the query successfully is returned. If no
+ *     sink is in the bin, the query fails.</para></listitem>
+ *   </varlistentry>
+ * </variablelist>
+ *
+ * A #GstBin will by default forward any event sent to it to all sink elements.
+ * If all the sinks return TRUE, the bin will also return TRUE, else FALSE is
+ * returned. If no sinks are in the bin, the event handler will return TRUE.
+ *
+ * </para>
+ * </refsect2>
+ *
+ * Last reviewed on 2006-04-28 (0.10.6)
+ */
+
+#include "gst_private.h"
+
+#include "gstevent.h"
+#include "gstbin.h"
+#include "gstmarshal.h"
+#include "gstxml.h"
+#include "gstinfo.h"
+#include "gsterror.h"
+
+#include "gstindex.h"
+#include "gstindexfactory.h"
+#include "gstutils.h"
+#include "gstchildproxy.h"
+
+#ifdef __SYMBIAN32__
+#include <glib_global.h>
+#endif
+
+/* enable for DURATION caching.
+ * FIXME currently too many elements don't update
+ * their duration when it changes so we return inaccurate values. */
+#undef DURATION_CACHING
+
+/* latency is by default enabled now.
+ * live-preroll and no-live-preroll in the environment var GST_COMPAT
+ * to enables or disable it respectively.
+ */
+static gboolean enable_latency = TRUE;
+
+GST_DEBUG_CATEGORY_STATIC (bin_debug);
+#define GST_CAT_DEFAULT bin_debug
+
+/* a bin is toplevel if it has no parent or when it is configured to behave like
+ * a toplevel bin */
+#define BIN_IS_TOPLEVEL(bin) ((GST_OBJECT_PARENT (bin) == NULL) || bin->priv->asynchandling)
+
+struct _GstBinPrivate
+{
+  gboolean asynchandling;
+};
+
+typedef struct
+{
+  GstBin *bin;
+  guint32 cookie;
+  GstState pending;
+} BinContinueData;
+
+static void gst_bin_dispose (GObject * object);
+
+static void gst_bin_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_bin_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static GstStateChangeReturn gst_bin_change_state_func (GstElement * element,
+    GstStateChange transition);
+static GstStateChangeReturn gst_bin_get_state_func (GstElement * element,
+    GstState * state, GstState * pending, GstClockTime timeout);
+static void bin_handle_async_done (GstBin * bin, GstStateChangeReturn ret);
+static void bin_handle_async_start (GstBin * bin, gboolean new_base_time);
+static void bin_push_state_continue (BinContinueData * data);
+
+static gboolean gst_bin_add_func (GstBin * bin, GstElement * element);
+static gboolean gst_bin_remove_func (GstBin * bin, GstElement * element);
+
+#ifndef GST_DISABLE_INDEX
+static void gst_bin_set_index_func (GstElement * element, GstIndex * index);
+#endif
+static GstClock *gst_bin_provide_clock_func (GstElement * element);
+static gboolean gst_bin_set_clock_func (GstElement * element, GstClock * clock);
+
+static void gst_bin_handle_message_func (GstBin * bin, GstMessage * message);
+static gboolean gst_bin_send_event (GstElement * element, GstEvent * event);
+static GstBusSyncReply bin_bus_handler (GstBus * bus,
+    GstMessage * message, GstBin * bin);
+static gboolean gst_bin_query (GstElement * element, GstQuery * query);
+
+#ifndef GST_DISABLE_LOADSAVE
+static xmlNodePtr gst_bin_save_thyself (GstObject * object, xmlNodePtr parent);
+static void gst_bin_restore_thyself (GstObject * object, xmlNodePtr self);
+#endif
+
+static void bin_remove_messages (GstBin * bin, GstObject * src,
+    GstMessageType types);
+static void gst_bin_continue_func (BinContinueData * data);
+static gint bin_element_is_sink (GstElement * child, GstBin * bin);
+static gint bin_element_is_src (GstElement * child, GstBin * bin);
+
+static GstIterator *gst_bin_sort_iterator_new (GstBin * bin);
+
+/* Bin signals and properties */
+enum
+{
+  ELEMENT_ADDED,
+  ELEMENT_REMOVED,
+  LAST_SIGNAL
+};
+
+#define DEFAULT_ASYNC_HANDLING	FALSE
+
+enum
+{
+  PROP_0,
+  PROP_ASYNC_HANDLING
+      /* FILL ME */
+};
+
+static void gst_bin_base_init (gpointer g_class);
+static void gst_bin_class_init (GstBinClass * klass);
+static void gst_bin_init (GstBin * bin);
+static void gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data);
+
+static GstElementClass *parent_class = NULL;
+static guint gst_bin_signals[LAST_SIGNAL] = { 0 };
+
+/**
+ * gst_bin_get_type:
+ *
+ * Returns: the type of #GstBin
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GType
+gst_bin_get_type (void)
+{
+  static GType gst_bin_type = 0;
+  const gchar *compat;
+
+  if (G_UNLIKELY (gst_bin_type == 0)) {
+    static const GTypeInfo bin_info = {
+      sizeof (GstBinClass),
+      gst_bin_base_init,
+      NULL,
+      (GClassInitFunc) gst_bin_class_init,
+      NULL,
+      NULL,
+      sizeof (GstBin),
+      0,
+      (GInstanceInitFunc) gst_bin_init,
+      NULL
+    };
+    static const GInterfaceInfo child_proxy_info = {
+      gst_bin_child_proxy_init,
+      NULL,
+      NULL
+    };
+
+    gst_bin_type =
+        g_type_register_static (GST_TYPE_ELEMENT, "GstBin", &bin_info, 0);
+
+    g_type_add_interface_static (gst_bin_type, GST_TYPE_CHILD_PROXY,
+        &child_proxy_info);
+
+    GST_DEBUG_CATEGORY_INIT (bin_debug, "bin", GST_DEBUG_BOLD,
+        "debugging info for the 'bin' container element");
+
+    /* compatibility stuff */
+    compat = g_getenv ("GST_COMPAT");
+    if (compat != NULL) {
+      if (strstr (compat, "no-live-preroll"))
+        enable_latency = FALSE;
+      else if (strstr (compat, "live-preroll"))
+        enable_latency = TRUE;
+    }
+  }
+  return gst_bin_type;
+}
+
+static void
+gst_bin_base_init (gpointer g_class)
+{
+  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details_simple (gstelement_class, "Generic bin",
+      "Generic/Bin",
+      "Simple container object",
+      "Erik Walthinsen <omega@cse.ogi.edu>,"
+      "Wim Taymans <wim.taymans@gmail.com>");
+}
+
+static GstObject *
+gst_bin_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
+    guint index)
+{
+  GstObject *res;
+  GstBin *bin;
+
+  bin = GST_BIN_CAST (child_proxy);
+
+  GST_OBJECT_LOCK (bin);
+  if ((res = g_list_nth_data (bin->children, index)))
+    gst_object_ref (res);
+  GST_OBJECT_UNLOCK (bin);
+
+  return res;
+}
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+guint
+gst_bin_child_proxy_get_children_count (GstChildProxy * child_proxy)
+{
+  guint num;
+  GstBin *bin;
+
+  bin = GST_BIN_CAST (child_proxy);
+
+  GST_OBJECT_LOCK (bin);
+  num = bin->numchildren;
+  GST_OBJECT_UNLOCK (bin);
+
+  return num;
+}
+
+static void
+gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data)
+{
+  GstChildProxyInterface *iface = g_iface;
+
+  iface->get_children_count = gst_bin_child_proxy_get_children_count;
+  iface->get_child_by_index = gst_bin_child_proxy_get_child_by_index;
+}
+
+static void
+gst_bin_class_init (GstBinClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstObjectClass *gstobject_class;
+  GstElementClass *gstelement_class;
+  GError *err;
+
+  gobject_class = (GObjectClass *) klass;
+  gstobject_class = (GstObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_bin_set_property);
+  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_bin_get_property);
+
+  /**
+   * GstBin:async-handling
+   *
+   * If set to #TRUE, the bin will handle asynchronous state changes.
+   * This should be used only if the bin subclass is modifying the state
+   * of its children on its own.
+   *
+   * Since: 0.10.13
+   */
+  g_object_class_install_property (gobject_class, PROP_ASYNC_HANDLING,
+      g_param_spec_boolean ("async-handling", "Async Handling",
+          "The bin will handle Asynchronous state changes",
+          DEFAULT_ASYNC_HANDLING, G_PARAM_READWRITE));
+
+  /**
+   * GstBin::element-added:
+   * @bin: the #GstBin
+   * @element: the #GstElement that was added to the bin
+   *
+   * Will be emitted after the element was added to the bin.
+   */
+  gst_bin_signals[ELEMENT_ADDED] =
+      g_signal_new ("element-added", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_added), NULL,
+      NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
+  /**
+   * GstBin::element-removed:
+   * @bin: the #GstBin
+   * @element: the #GstElement that was removed from the bin
+   *
+   * Will be emitted after the element was removed from the bin.
+   */
+  gst_bin_signals[ELEMENT_REMOVED] =
+      g_signal_new ("element-removed", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_removed), NULL,
+      NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
+
+  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_bin_dispose);
+
+#ifndef GST_DISABLE_LOADSAVE
+  gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_bin_save_thyself);
+  gstobject_class->restore_thyself =
+      GST_DEBUG_FUNCPTR (gst_bin_restore_thyself);
+#endif
+
+  gstelement_class->change_state =
+      GST_DEBUG_FUNCPTR (gst_bin_change_state_func);
+  gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state_func);
+#ifndef GST_DISABLE_INDEX
+  gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
+#endif
+  gstelement_class->provide_clock =
+      GST_DEBUG_FUNCPTR (gst_bin_provide_clock_func);
+  gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
+
+  gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
+  gstelement_class->query = GST_DEBUG_FUNCPTR (gst_bin_query);
+
+  klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
+  klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
+  klass->handle_message = GST_DEBUG_FUNCPTR (gst_bin_handle_message_func);
+
+  GST_DEBUG ("creating bin thread pool");
+  err = NULL;
+  klass->pool =
+      g_thread_pool_new ((GFunc) gst_bin_continue_func, NULL, -1, FALSE, &err);
+  if (err != NULL) {
+    g_critical ("could alloc threadpool %s", err->message);
+  }
+}
+
+static void
+gst_bin_init (GstBin * bin)
+{
+  GstBus *bus;
+
+  bin->numchildren = 0;
+  bin->children = NULL;
+  bin->children_cookie = 0;
+  bin->messages = NULL;
+  bin->provided_clock = NULL;
+  bin->clock_dirty = FALSE;
+
+  /* Set up a bus for listening to child elements */
+  bus = gst_bus_new ();
+  bin->child_bus = bus;
+  GST_DEBUG_OBJECT (bin, "using bus %" GST_PTR_FORMAT " to listen to children",
+      bus);
+  gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin);
+
+  bin->priv = g_new0 (GstBinPrivate, 1);
+  bin->priv->asynchandling = DEFAULT_ASYNC_HANDLING;
+}
+
+static void
+gst_bin_dispose (GObject * object)
+{
+  GstBin *bin = GST_BIN (object);
+  GstBus **child_bus_p = &bin->child_bus;
+  GstClock **provided_clock_p = &bin->provided_clock;
+  GstElement **clock_provider_p = &bin->clock_provider;
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
+
+  bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
+
+  gst_object_replace ((GstObject **) child_bus_p, NULL);
+  gst_object_replace ((GstObject **) provided_clock_p, NULL);
+  gst_object_replace ((GstObject **) clock_provider_p, NULL);
+
+  while (bin->children) {
+    gst_bin_remove (bin, GST_ELEMENT_CAST (bin->children->data));
+  }
+  if (G_UNLIKELY (bin->children != NULL)) {
+    g_critical ("could not remove elements from bin %s",
+        GST_STR_NULL (GST_OBJECT_NAME (object)));
+  }
+
+  if (bin->priv) {
+    g_free (bin->priv);
+    bin->priv = NULL;
+  }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+/**
+ * gst_bin_new:
+ * @name: the name of the new bin
+ *
+ * Creates a new bin with the given name.
+ *
+ * Returns: a new #GstBin
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstElement *
+gst_bin_new (const gchar * name)
+{
+  return gst_element_factory_make ("bin", name);
+}
+
+static void
+gst_bin_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstBin *gstbin;
+
+  gstbin = GST_BIN (object);
+
+  switch (prop_id) {
+    case PROP_ASYNC_HANDLING:
+      GST_OBJECT_LOCK (gstbin);
+      gstbin->priv->asynchandling = g_value_get_boolean (value);
+      GST_OBJECT_UNLOCK (gstbin);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_bin_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstBin *gstbin;
+
+  gstbin = GST_BIN (object);
+
+  switch (prop_id) {
+    case PROP_ASYNC_HANDLING:
+      GST_OBJECT_LOCK (gstbin);
+      g_value_set_boolean (value, gstbin->priv->asynchandling);
+      GST_OBJECT_UNLOCK (gstbin);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/* set the index on all elements in this bin
+ *
+ * MT safe
+ */
+#ifndef GST_DISABLE_INDEX
+static void
+gst_bin_set_index_func (GstElement * element, GstIndex * index)
+{
+  GstBin *bin;
+  GList *children;
+
+  bin = GST_BIN (element);
+
+  GST_OBJECT_LOCK (bin);
+  for (children = bin->children; children; children = g_list_next (children)) {
+    GstElement *child = GST_ELEMENT (children->data);
+
+    gst_element_set_index (child, index);
+  }
+  GST_OBJECT_UNLOCK (bin);
+}
+#endif
+
+/* set the clock on all elements in this bin
+ *
+ * MT safe
+ */
+static gboolean
+gst_bin_set_clock_func (GstElement * element, GstClock * clock)
+{
+  GList *children;
+  GstBin *bin;
+  gboolean res = TRUE;
+
+  bin = GST_BIN (element);
+
+  GST_OBJECT_LOCK (bin);
+  if (element->clock != clock) {
+    for (children = bin->children; children; children = g_list_next (children)) {
+      GstElement *child = GST_ELEMENT (children->data);
+
+      res &= gst_element_set_clock (child, clock);
+    }
+  }
+  GST_OBJECT_UNLOCK (bin);
+
+  return res;
+}
+
+/* get the clock for this bin by asking all of the children in this bin
+ *
+ * The ref of the returned clock in increased so unref after usage.
+ *
+ * We loop the elements in state order and pick the last clock we can
+ * get. This makes sure we get a clock from the source.
+ *
+ * MT safe
+ */
+static GstClock *
+gst_bin_provide_clock_func (GstElement * element)
+{
+  GstClock *result = NULL;
+  GstElement *provider = NULL;
+  GstBin *bin;
+  GstIterator *it;
+  gpointer val;
+  GstClock **provided_clock_p;
+  GstElement **clock_provider_p;
+
+  bin = GST_BIN (element);
+
+  GST_OBJECT_LOCK (bin);
+  if (!bin->clock_dirty)
+    goto not_dirty;
+
+  GST_DEBUG_OBJECT (bin, "finding new clock");
+
+  it = gst_bin_sort_iterator_new (bin);
+
+  while (it->next (it, &val) == GST_ITERATOR_OK) {
+    GstElement *child = GST_ELEMENT_CAST (val);
+    GstClock *clock;
+
+    clock = gst_element_provide_clock (child);
+    if (clock) {
+      GST_DEBUG_OBJECT (bin, "found candidate clock %p by element %s",
+          clock, GST_ELEMENT_NAME (child));
+      if (result) {
+        gst_object_unref (result);
+        gst_object_unref (provider);
+      }
+      result = clock;
+      provider = child;
+    } else {
+      gst_object_unref (child);
+    }
+  }
+
+  provided_clock_p = &bin->provided_clock;
+  clock_provider_p = &bin->clock_provider;
+  gst_object_replace ((GstObject **) provided_clock_p, (GstObject *) result);
+  gst_object_replace ((GstObject **) clock_provider_p, (GstObject *) provider);
+  bin->clock_dirty = FALSE;
+  GST_DEBUG_OBJECT (bin,
+      "provided new clock %" GST_PTR_FORMAT " by provider %" GST_PTR_FORMAT,
+      result, provider);
+  /* Provider is not being returned to caller, just the result */
+  if (provider)
+    gst_object_unref (provider);
+  GST_OBJECT_UNLOCK (bin);
+
+  gst_iterator_free (it);
+
+  return result;
+
+not_dirty:
+  {
+    if ((result = bin->provided_clock))
+      gst_object_ref (result);
+    GST_DEBUG_OBJECT (bin, "returning old clock %p", result);
+    GST_OBJECT_UNLOCK (bin);
+
+    return result;
+  }
+}
+
+/*
+ * functions for manipulating cached messages
+ */
+typedef struct
+{
+  GstObject *src;
+  GstMessageType types;
+} MessageFind;
+
+/* check if a message is of given src and type */
+static gint
+message_check (GstMessage * message, MessageFind * target)
+{
+  gboolean eq = TRUE;
+
+  if (target->src)
+    eq &= GST_MESSAGE_SRC (message) == target->src;
+  if (target->types)
+    eq &= (GST_MESSAGE_TYPE (message) & target->types) != 0;
+
+  return (eq ? 0 : 1);
+}
+
+static GList *
+find_message (GstBin * bin, GstObject * src, GstMessageType types)
+{
+  GList *result;
+  MessageFind find;
+
+  find.src = src;
+  find.types = types;
+
+  result = g_list_find_custom (bin->messages, &find,
+      (GCompareFunc) message_check);
+
+  if (result) {
+    GST_DEBUG_OBJECT (bin, "we found a message %p from %s matching types %08x",
+        result->data, GST_OBJECT_NAME (GST_MESSAGE_CAST (result->data)->src),
+        types);
+  } else {
+    GST_DEBUG_OBJECT (bin, "no message found matching types %08x", types);
+#ifndef GST_DISABLE_GST_DEBUG
+    {
+      guint i;
+
+      for (i = 0; i < 32; i++)
+        if (types & (1 << i))
+          GST_DEBUG_OBJECT (bin, "  %s", gst_message_type_get_name (1 << i));
+    }
+#endif
+  }
+
+  return result;
+}
+
+/* with LOCK, returns TRUE if message had a valid SRC, takes ref on
+ * the message.
+ *
+ * A message that is cached and has the same SRC and type is replaced
+ * by the given message.
+ */
+static gboolean
+bin_replace_message (GstBin * bin, GstMessage * message, GstMessageType types)
+{
+  GList *previous;
+  GstObject *src;
+  gboolean res = TRUE;
+  const gchar *name;
+
+  name = GST_MESSAGE_TYPE_NAME (message);
+
+  if ((src = GST_MESSAGE_SRC (message))) {
+    /* first find the previous message posted by this element */
+    if ((previous = find_message (bin, src, types))) {
+      /* if we found a previous message, replace it */
+      gst_message_unref (previous->data);
+      previous->data = message;
+
+      GST_DEBUG_OBJECT (bin, "replace old message %s from %s",
+          name, GST_ELEMENT_NAME (src));
+    } else {
+      /* keep new message */
+      bin->messages = g_list_prepend (bin->messages, message);
+
+      GST_DEBUG_OBJECT (bin, "got new message %p, %s from %s",
+          message, name, GST_ELEMENT_NAME (src));
+    }
+  } else {
+    GST_DEBUG_OBJECT (bin, "got message %s from (NULL), not processing", name);
+    res = FALSE;
+    gst_message_unref (message);
+  }
+  return res;
+}
+
+/* with LOCK. Remove all messages of given types */
+static void
+bin_remove_messages (GstBin * bin, GstObject * src, GstMessageType types)
+{
+  MessageFind find;
+  GList *walk, *next;
+
+  find.src = src;
+  find.types = types;
+
+  for (walk = bin->messages; walk; walk = next) {
+    GstMessage *message = (GstMessage *) walk->data;
+
+    next = g_list_next (walk);
+
+    if (message_check (message, &find) == 0) {
+      GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
+          "deleting message %p of types 0x%08x", message, types);
+      bin->messages = g_list_delete_link (bin->messages, walk);
+      gst_message_unref (message);
+    } else {
+      GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
+          "not deleting message %p of type 0x%08x", message,
+          GST_MESSAGE_TYPE (message));
+    }
+  }
+}
+
+
+/* Check if the bin is EOS. We do this by scanning all sinks and
+ * checking if they posted an EOS message.
+ *
+ * call with bin LOCK */
+static gboolean
+is_eos (GstBin * bin)
+{
+  gboolean result;
+  GList *walk;
+
+  result = TRUE;
+  for (walk = bin->children; walk; walk = g_list_next (walk)) {
+    GstElement *element;
+
+    element = GST_ELEMENT_CAST (walk->data);
+    if (bin_element_is_sink (element, bin) == 0) {
+      /* check if element posted EOS */
+      if (find_message (bin, GST_OBJECT_CAST (element), GST_MESSAGE_EOS)) {
+        GST_DEBUG ("sink '%s' posted EOS", GST_ELEMENT_NAME (element));
+      } else {
+        GST_DEBUG ("sink '%s' did not post EOS yet",
+            GST_ELEMENT_NAME (element));
+        result = FALSE;
+        break;
+      }
+    }
+  }
+  return result;
+}
+
+static void
+unlink_pads (GstPad * pad)
+{
+  GstPad *peer;
+
+  if ((peer = gst_pad_get_peer (pad))) {
+    if (gst_pad_get_direction (pad) == GST_PAD_SRC)
+      gst_pad_unlink (pad, peer);
+    else
+      gst_pad_unlink (peer, pad);
+    gst_object_unref (peer);
+  }
+  gst_object_unref (pad);
+}
+
+/* vmethod that adds an element to a bin
+ *
+ * MT safe
+ */
+static gboolean
+gst_bin_add_func (GstBin * bin, GstElement * element)
+{
+  gchar *elem_name;
+  GstIterator *it;
+  gboolean is_sink;
+  GstMessage *clock_message = NULL, *async_message = NULL;
+  GstStateChangeReturn ret;
+
+  GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
+
+  /* we obviously can't add ourself to ourself */
+  if (G_UNLIKELY (GST_ELEMENT_CAST (element) == GST_ELEMENT_CAST (bin)))
+    goto adding_itself;
+
+  /* get the element name to make sure it is unique in this bin. */
+  GST_OBJECT_LOCK (element);
+  elem_name = g_strdup (GST_ELEMENT_NAME (element));
+  is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
+  GST_OBJECT_UNLOCK (element);
+
+  GST_OBJECT_LOCK (bin);
+
+  /* then check to see if the element's name is already taken in the bin,
+   * we can safely take the lock here. This check is probably bogus because
+   * you can safely change the element name after this check and before setting
+   * the object parent. The window is very small though... */
+  if (G_UNLIKELY (!gst_object_check_uniqueness (bin->children, elem_name)))
+    goto duplicate_name;
+
+  /* set the element's parent and add the element to the bin's list of children */
+  if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (element),
+              GST_OBJECT_CAST (bin))))
+    goto had_parent;
+
+  /* if we add a sink we become a sink */
+  if (is_sink) {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was sink",
+        elem_name);
+    GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_IS_SINK);
+  }
+  if (gst_element_provides_clock (element)) {
+    GST_DEBUG_OBJECT (bin, "element \"%s\" can provide a clock", elem_name);
+    clock_message =
+        gst_message_new_clock_provide (GST_OBJECT_CAST (element), NULL, TRUE);
+  }
+
+  bin->children = g_list_prepend (bin->children, element);
+  bin->numchildren++;
+  bin->children_cookie++;
+
+  /* distribute the bus */
+  gst_element_set_bus (element, bin->child_bus);
+
+  /* propagate the current base_time and clock */
+  gst_element_set_base_time (element, GST_ELEMENT (bin)->base_time);
+  /* it's possible that the element did not accept the clock but
+   * that is not important right now. When the pipeline goes to PLAYING,
+   * a new clock will be selected */
+  gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
+
+  ret = GST_STATE_RETURN (bin);
+  /* no need to update the state if we are in error */
+  if (ret == GST_STATE_CHANGE_FAILURE)
+    goto no_state_recalc;
+
+  /* update the bin state, the new element could have been an ASYNC or
+   * NO_PREROLL element */
+  ret = GST_STATE_RETURN (element);
+  GST_DEBUG_OBJECT (bin, "added %s element",
+      gst_element_state_change_return_get_name (ret));
+
+  switch (ret) {
+    case GST_STATE_CHANGE_ASYNC:
+    {
+      /* create message to track this aync element when it posts an async-done
+       * message */
+      async_message =
+          gst_message_new_async_start (GST_OBJECT_CAST (element), FALSE);
+      break;
+    }
+    case GST_STATE_CHANGE_NO_PREROLL:
+      /* ignore all async elements we might have and commit our state */
+      bin_handle_async_done (bin, ret);
+      break;
+    case GST_STATE_CHANGE_FAILURE:
+      break;
+    default:
+      break;
+  }
+
+no_state_recalc:
+  GST_OBJECT_UNLOCK (bin);
+
+  /* post the messages on the bus of the element so that the bin can handle
+   * them */
+  if (clock_message)
+    gst_element_post_message (GST_ELEMENT_CAST (element), clock_message);
+
+  if (async_message)
+    gst_element_post_message (GST_ELEMENT_CAST (element), async_message);
+
+  /* unlink all linked pads */
+  it = gst_element_iterate_pads (element);
+  gst_iterator_foreach (it, (GFunc) unlink_pads, element);
+  gst_iterator_free (it);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "added element \"%s\"",
+      elem_name);
+  g_free (elem_name);
+
+  g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_ADDED], 0, element);
+
+  return TRUE;
+
+  /* ERROR handling here */
+adding_itself:
+  {
+    GST_OBJECT_LOCK (bin);
+    g_warning ("Cannot add bin %s to itself", GST_ELEMENT_NAME (bin));
+    GST_OBJECT_UNLOCK (bin);
+    return FALSE;
+  }
+duplicate_name:
+  {
+    g_warning ("Name %s is not unique in bin %s, not adding",
+        elem_name, GST_ELEMENT_NAME (bin));
+    GST_OBJECT_UNLOCK (bin);
+    g_free (elem_name);
+    return FALSE;
+  }
+had_parent:
+  {
+    g_warning ("Element %s already has parent", elem_name);
+    GST_OBJECT_UNLOCK (bin);
+    g_free (elem_name);
+    return FALSE;
+  }
+}
+
+/**
+ * gst_bin_add:
+ * @bin: a #GstBin
+ * @element: the #GstElement to add
+ *
+ * Adds the given element to the bin.  Sets the element's parent, and thus
+ * takes ownership of the element. An element can only be added to one bin.
+ *
+ * If the element's pads are linked to other pads, the pads will be unlinked
+ * before the element is added to the bin.
+ *
+ * MT safe.
+ *
+ * Returns: TRUE if the element could be added, FALSE if
+ * the bin does not want to accept the element.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_bin_add (GstBin * bin, GstElement * element)
+{
+  GstBinClass *bclass;
+  gboolean result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
+  g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
+
+  bclass = GST_BIN_GET_CLASS (bin);
+
+  if (G_UNLIKELY (bclass->add_element == NULL))
+    goto no_function;
+
+  GST_CAT_DEBUG (GST_CAT_PARENTAGE, "adding element %s to bin %s",
+      GST_STR_NULL (GST_ELEMENT_NAME (element)),
+      GST_STR_NULL (GST_ELEMENT_NAME (bin)));
+
+  result = bclass->add_element (bin, element);
+
+  return result;
+
+  /* ERROR handling */
+no_function:
+  {
+    g_warning ("adding elements to bin %s is not supported",
+        GST_ELEMENT_NAME (bin));
+    return FALSE;
+  }
+}
+
+/* remove an element from the bin
+ *
+ * MT safe
+ */
+static gboolean
+gst_bin_remove_func (GstBin * bin, GstElement * element)
+{
+  gchar *elem_name;
+  GstIterator *it;
+  gboolean is_sink, othersink, found;
+  GstMessage *clock_message = NULL;
+  GList *walk, *next;
+  gboolean other_async, this_async, have_no_preroll;
+  GstStateChangeReturn ret;
+
+  GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
+
+  GST_OBJECT_LOCK (element);
+  /* Check if the element is already being removed and immediately
+   * return */
+  if (G_UNLIKELY (GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_UNPARENTING)))
+    goto already_removing;
+
+  GST_OBJECT_FLAG_SET (element, GST_ELEMENT_UNPARENTING);
+  /* grab element name so we can print it */
+  elem_name = g_strdup (GST_ELEMENT_NAME (element));
+  is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
+  GST_OBJECT_UNLOCK (element);
+
+  /* unlink all linked pads */
+  it = gst_element_iterate_pads (element);
+  gst_iterator_foreach (it, (GFunc) unlink_pads, element);
+  gst_iterator_free (it);
+
+  GST_OBJECT_LOCK (bin);
+  found = FALSE;
+  othersink = FALSE;
+  have_no_preroll = FALSE;
+  /* iterate the elements, we collect which ones are async and no_preroll. We
+   * also remove the element when we find it. */
+  for (walk = bin->children; walk; walk = next) {
+    GstElement *child = GST_ELEMENT_CAST (walk->data);
+
+    next = g_list_next (walk);
+
+    if (child == element) {
+      found = TRUE;
+      /* remove the element */
+      bin->children = g_list_delete_link (bin->children, walk);
+    } else {
+      gboolean child_sink;
+
+      GST_OBJECT_LOCK (child);
+      child_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK);
+      /* when we remove a sink, check if there are other sinks. */
+      if (is_sink && !othersink && child_sink)
+        othersink = TRUE;
+      /* check if we have NO_PREROLL children */
+      if (GST_STATE_RETURN (child) == GST_STATE_CHANGE_NO_PREROLL)
+        have_no_preroll = TRUE;
+      GST_OBJECT_UNLOCK (child);
+    }
+  }
+
+  /* the element must have been in the bin's list of children */
+  if (G_UNLIKELY (!found))
+    goto not_in_bin;
+
+  /* we now removed the element from the list of elements, increment the cookie
+   * so that others can detect a change in the children list. */
+  bin->numchildren--;
+  bin->children_cookie++;
+
+  if (is_sink && !othersink) {
+    /* we're not a sink anymore */
+    GST_DEBUG_OBJECT (bin, "we removed the last sink");
+    GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_IS_SINK);
+  }
+
+  /* if the clock provider for this element is removed, we lost
+   * the clock as well, we need to inform the parent of this
+   * so that it can select a new clock */
+  if (bin->clock_provider == element) {
+    GST_DEBUG_OBJECT (bin, "element \"%s\" provided the clock", elem_name);
+    bin->clock_dirty = TRUE;
+    clock_message =
+        gst_message_new_clock_lost (GST_OBJECT_CAST (bin), bin->provided_clock);
+  }
+
+  /* remove messages for the element, if there was a pending ASYNC_START
+   * message we must see if removing the element caused the bin to lose its
+   * async state. */
+  this_async = FALSE;
+  other_async = FALSE;
+  for (walk = bin->messages; walk; walk = next) {
+    GstMessage *message = (GstMessage *) walk->data;
+    GstElement *src = GST_ELEMENT_CAST (GST_MESSAGE_SRC (message));
+
+    next = g_list_next (walk);
+
+    if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ASYNC_START) {
+      if (src == element)
+        this_async = TRUE;
+      else
+        other_async = TRUE;
+
+      GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
+          "looking at message %p", message);
+    }
+    if (src == element) {
+      /* delete all message types */
+      GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
+          "deleting message %p of element \"%s\"", message, elem_name);
+      bin->messages = g_list_delete_link (bin->messages, walk);
+      gst_message_unref (message);
+    }
+  }
+
+  /* get last return */
+  ret = GST_STATE_RETURN (bin);
+
+  /* no need to update the state if we are in error */
+  if (ret == GST_STATE_CHANGE_FAILURE)
+    goto no_state_recalc;
+
+  if (!other_async && this_async) {
+    /* all other elements were not async and we removed the async one,
+     * handle the async-done case because we are not async anymore now. */
+    GST_DEBUG_OBJECT (bin,
+        "we removed the last async element, have no_preroll %d",
+        have_no_preroll);
+
+    /* the current state return of the bin depends on if there are no_preroll
+     * elements in the pipeline or not */
+    if (have_no_preroll)
+      ret = GST_STATE_CHANGE_NO_PREROLL;
+    else
+      ret = GST_STATE_CHANGE_SUCCESS;
+
+    bin_handle_async_done (bin, ret);
+  } else {
+    GST_DEBUG_OBJECT (bin,
+        "recalc state preroll: %d, other async: %d, this async %d",
+        have_no_preroll, other_async, this_async);
+
+    if (have_no_preroll) {
+      ret = GST_STATE_CHANGE_NO_PREROLL;
+    } else if (other_async) {
+      /* there are other async elements and we were not doing an async state
+       * change, change our pending state and go async */
+      if (GST_STATE_PENDING (bin) == GST_STATE_VOID_PENDING) {
+        GST_STATE_NEXT (bin) = GST_STATE (bin);
+        GST_STATE_PENDING (bin) = GST_STATE (bin);
+      }
+      ret = GST_STATE_CHANGE_ASYNC;
+    }
+    GST_STATE_RETURN (bin) = ret;
+  }
+no_state_recalc:
+  GST_OBJECT_UNLOCK (bin);
+
+  if (clock_message)
+    gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message);
+
+  GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
+      elem_name);
+  g_free (elem_name);
+
+  gst_element_set_bus (element, NULL);
+
+  /* Clear the clock we provided to the element */
+  gst_element_set_clock (element, NULL);
+
+  /* we ref here because after the _unparent() the element can be disposed
+   * and we still need it to reset the UNPARENTING flag and fire a signal. */
+  gst_object_ref (element);
+  gst_object_unparent (GST_OBJECT_CAST (element));
+
+  GST_OBJECT_LOCK (element);
+  GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_UNPARENTING);
+  GST_OBJECT_UNLOCK (element);
+
+  g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_REMOVED], 0, element);
+
+  /* element is really out of our control now */
+  gst_object_unref (element);
+
+  return TRUE;
+
+  /* ERROR handling */
+not_in_bin:
+  {
+    g_warning ("Element %s is not in bin %s", elem_name,
+        GST_ELEMENT_NAME (bin));
+    GST_OBJECT_UNLOCK (bin);
+    g_free (elem_name);
+    return FALSE;
+  }
+already_removing:
+  {
+    GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "already removing child");
+    GST_OBJECT_UNLOCK (element);
+    return FALSE;
+  }
+}
+
+/**
+ * gst_bin_remove:
+ * @bin: a #GstBin
+ * @element: the #GstElement to remove
+ *
+ * Removes the element from the bin, unparenting it as well.
+ * Unparenting the element means that the element will be dereferenced,
+ * so if the bin holds the only reference to the element, the element
+ * will be freed in the process of removing it from the bin.  If you
+ * want the element to still exist after removing, you need to call
+ * gst_object_ref() before removing it from the bin.
+ *
+ * If the element's pads are linked to other pads, the pads will be unlinked
+ * before the element is removed from the bin.
+ *
+ * MT safe.
+ *
+ * Returns: TRUE if the element could be removed, FALSE if
+ * the bin does not want to remove the element.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_bin_remove (GstBin * bin, GstElement * element)
+{
+  GstBinClass *bclass;
+  gboolean result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
+  g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
+
+  bclass = GST_BIN_GET_CLASS (bin);
+
+  if (G_UNLIKELY (bclass->remove_element == NULL))
+    goto no_function;
+
+  GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s",
+      GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
+
+  result = bclass->remove_element (bin, element);
+
+  return result;
+
+  /* ERROR handling */
+no_function:
+  {
+    g_warning ("removing elements from bin %s is not supported",
+        GST_ELEMENT_NAME (bin));
+    return FALSE;
+  }
+}
+
+static GstIteratorItem
+iterate_child (GstIterator * it, GstElement * child)
+{
+  gst_object_ref (child);
+  return GST_ITERATOR_ITEM_PASS;
+}
+
+/**
+ * gst_bin_iterate_elements:
+ * @bin: a #GstBin
+ *
+ * Gets an iterator for the elements in this bin.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_elements (GstBin * bin)
+{
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  GST_OBJECT_LOCK (bin);
+  /* add ref because the iterator refs the bin. When the iterator
+   * is freed it will unref the bin again using the provided dispose
+   * function. */
+  gst_object_ref (bin);
+  result = gst_iterator_new_list (GST_TYPE_ELEMENT,
+      GST_OBJECT_GET_LOCK (bin),
+      &bin->children_cookie,
+      &bin->children,
+      bin,
+      (GstIteratorItemFunction) iterate_child,
+      (GstIteratorDisposeFunction) gst_object_unref);
+  GST_OBJECT_UNLOCK (bin);
+
+  return result;
+}
+
+static GstIteratorItem
+iterate_child_recurse (GstIterator * it, GstElement * child)
+{
+  gst_object_ref (child);
+  if (GST_IS_BIN (child)) {
+    GstIterator *other = gst_bin_iterate_recurse (GST_BIN (child));
+
+    gst_iterator_push (it, other);
+  }
+  return GST_ITERATOR_ITEM_PASS;
+}
+
+/**
+ * gst_bin_iterate_recurse:
+ * @bin: a #GstBin
+ *
+ * Gets an iterator for the elements in this bin.
+ * This iterator recurses into GstBin children.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_recurse (GstBin * bin)
+{
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  GST_OBJECT_LOCK (bin);
+  /* add ref because the iterator refs the bin. When the iterator
+   * is freed it will unref the bin again using the provided dispose
+   * function. */
+  gst_object_ref (bin);
+  result = gst_iterator_new_list (GST_TYPE_ELEMENT,
+      GST_OBJECT_GET_LOCK (bin),
+      &bin->children_cookie,
+      &bin->children,
+      bin,
+      (GstIteratorItemFunction) iterate_child_recurse,
+      (GstIteratorDisposeFunction) gst_object_unref);
+  GST_OBJECT_UNLOCK (bin);
+
+  return result;
+}
+
+/* returns 0 when TRUE because this is a GCompareFunc */
+/* MT safe */
+static gint
+bin_element_is_sink (GstElement * child, GstBin * bin)
+{
+  gboolean is_sink;
+
+  /* we lock the child here for the remainder of the function to
+   * get its name and flag safely. */
+  GST_OBJECT_LOCK (child);
+  is_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
+      "child %s %s sink", GST_OBJECT_NAME (child), is_sink ? "is" : "is not");
+
+  GST_OBJECT_UNLOCK (child);
+  return is_sink ? 0 : 1;
+}
+
+static gint
+sink_iterator_filter (GstElement * child, GstBin * bin)
+{
+  if (bin_element_is_sink (child, bin) == 0) {
+    /* returns 0 because this is a GCompareFunc */
+    return 0;
+  } else {
+    /* child carries a ref from gst_bin_iterate_elements -- drop if not passing
+       through */
+    gst_object_unref (child);
+    return 1;
+  }
+}
+
+/**
+ * gst_bin_iterate_sinks:
+ * @bin: a #GstBin
+ *
+ * Gets an iterator for all elements in the bin that have the
+ * #GST_ELEMENT_IS_SINK flag set.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_sinks (GstBin * bin)
+{
+  GstIterator *children;
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  children = gst_bin_iterate_elements (bin);
+  result = gst_iterator_filter (children,
+      (GCompareFunc) sink_iterator_filter, bin);
+
+  return result;
+}
+
+/* returns 0 when TRUE because this is a GCompareFunc */
+/* MT safe */
+static gint
+bin_element_is_src (GstElement * child, GstBin * bin)
+{
+  gboolean is_src = FALSE;
+
+  /* we lock the child here for the remainder of the function to
+   * get its name and flag safely. */
+  GST_OBJECT_LOCK (child);
+  if (!GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK) &&
+      !child->numsinkpads) {
+    is_src = TRUE;
+  }
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
+      "child %s %s src", GST_OBJECT_NAME (child), is_src ? "is" : "is not");
+
+  GST_OBJECT_UNLOCK (child);
+  return is_src ? 0 : 1;
+}
+
+static gint
+src_iterator_filter (GstElement * child, GstBin * bin)
+{
+  if (bin_element_is_src (child, bin) == 0) {
+    /* returns 0 because this is a GCompareFunc */
+    return 0;
+  } else {
+    /* child carries a ref from gst_bin_iterate_elements -- drop if not passing
+       through */
+    gst_object_unref (child);
+    return 1;
+  }
+}
+
+/**
+ * gst_bin_iterate_sources:
+ * @bin: a #GstBin
+ *
+ * Gets an iterator for all elements in the bin that have no sinkpads and have
+ * the #GST_ELEMENT_IS_SINK flag unset.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_sources (GstBin * bin)
+{
+  GstIterator *children;
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  children = gst_bin_iterate_elements (bin);
+  result = gst_iterator_filter (children,
+      (GCompareFunc) src_iterator_filter, bin);
+
+  return result;
+}
+
+/*
+ * MT safe
+ */
+static GstStateChangeReturn
+gst_bin_get_state_func (GstElement * element, GstState * state,
+    GstState * pending, GstClockTime timeout)
+{
+  GstStateChangeReturn ret;
+
+  GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "getting state");
+
+  ret = parent_class->get_state (element, state, pending, timeout);
+
+  return ret;
+}
+
+/***********************************************
+ * Topologically sorted iterator
+ * see http://en.wikipedia.org/wiki/Topological_sorting
+ *
+ * For each element in the graph, an entry is kept in a HashTable
+ * with its number of srcpad connections (degree).
+ * We then change state of all elements without dependencies
+ * (degree 0) and decrement the degree of all elements connected
+ * on the sinkpads. When an element reaches degree 0, its state is
+ * changed next.
+ * When all elements are handled the algorithm stops.
+ */
+typedef struct _GstBinSortIterator
+{
+  GstIterator it;
+  GQueue *queue;                /* elements queued for state change */
+  GstBin *bin;                  /* bin we iterate */
+  gint mode;                    /* adding or removing dependency */
+  GstElement *best;             /* next element with least dependencies */
+  gint best_deg;                /* best degree */
+  GHashTable *hash;             /* hashtable with element dependencies */
+} GstBinSortIterator;
+
+/* we add and subtract 1 to make sure we don't confuse NULL and 0 */
+#define HASH_SET_DEGREE(bit, elem, deg) \
+    g_hash_table_replace (bit->hash, elem, GINT_TO_POINTER(deg+1))
+#define HASH_GET_DEGREE(bit, elem) \
+    (GPOINTER_TO_INT(g_hash_table_lookup (bit->hash, elem))-1)
+
+/* add element to queue of next elements in the iterator.
+ * We push at the tail to give higher priority elements a
+ * chance first */
+static void
+add_to_queue (GstBinSortIterator * bit, GstElement * element)
+{
+  GST_DEBUG_OBJECT (bit->bin, "adding '%s' to queue",
+      GST_ELEMENT_NAME (element));
+  gst_object_ref (element);
+  g_queue_push_tail (bit->queue, element);
+  HASH_SET_DEGREE (bit, element, -1);
+}
+
+static void
+remove_from_queue (GstBinSortIterator * bit, GstElement * element)
+{
+  GList *find;
+
+  if ((find = g_queue_find (bit->queue, element))) {
+    GST_DEBUG_OBJECT (bit->bin, "removing '%s' from queue",
+        GST_ELEMENT_NAME (element));
+
+    g_queue_delete_link (bit->queue, find);
+    gst_object_unref (element);
+  } else {
+    GST_DEBUG_OBJECT (bit->bin, "unable to remove '%s' from queue",
+        GST_ELEMENT_NAME (element));
+  }
+}
+
+/* clear the queue, unref all objects as we took a ref when
+ * we added them to the queue */
+static void
+clear_queue (GQueue * queue)
+{
+  gpointer p;
+
+  while ((p = g_queue_pop_head (queue)))
+    gst_object_unref (p);
+}
+
+/* set all degrees to 0. Elements marked as a sink are
+ * added to the queue immediatly. Since we only look at the SINK flag of the
+ * element, it is possible that we add non-sinks to the queue. These will be
+ * removed from the queue again when we can prove that it provides data for some
+ * other element. */
+static void
+reset_degree (GstElement * element, GstBinSortIterator * bit)
+{
+  gboolean is_sink;
+
+  /* sinks are added right away */
+  GST_OBJECT_LOCK (element);
+  is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
+  GST_OBJECT_UNLOCK (element);
+
+  if (is_sink) {
+    add_to_queue (bit, element);
+  } else {
+    /* others are marked with 0 and handled when sinks are done */
+    HASH_SET_DEGREE (bit, element, 0);
+  }
+}
+
+/* adjust the degree of all elements connected to the given
+ * element. If a degree of an element drops to 0, it is
+ * added to the queue of elements to schedule next.
+ *
+ * We have to make sure not to cross the bin boundary this element
+ * belongs to.
+ */
+static void
+update_degree (GstElement * element, GstBinSortIterator * bit)
+{
+  gboolean linked = FALSE;
+
+  GST_OBJECT_LOCK (element);
+  /* don't touch degree if element has no sourcepads */
+  if (element->numsinkpads != 0) {
+    /* loop over all sinkpads, decrement degree for all connected
+     * elements in this bin */
+    GList *pads;
+
+    for (pads = element->sinkpads; pads; pads = g_list_next (pads)) {
+      GstPad *peer;
+
+      if ((peer = gst_pad_get_peer (GST_PAD_CAST (pads->data)))) {
+        GstElement *peer_element;
+
+        if ((peer_element = gst_pad_get_parent_element (peer))) {
+          GST_OBJECT_LOCK (peer_element);
+          /* check that we don't go outside of this bin */
+          if (GST_OBJECT_CAST (peer_element)->parent ==
+              GST_OBJECT_CAST (bit->bin)) {
+            gint old_deg, new_deg;
+
+            old_deg = HASH_GET_DEGREE (bit, peer_element);
+
+            /* check to see if we added an element as sink that was not really a
+             * sink because it was connected to some other element. */
+            if (old_deg == -1) {
+              remove_from_queue (bit, peer_element);
+              old_deg = 0;
+            }
+            new_deg = old_deg + bit->mode;
+
+            GST_DEBUG_OBJECT (bit->bin,
+                "change element %s, degree %d->%d, linked to %s",
+                GST_ELEMENT_NAME (peer_element), old_deg, new_deg,
+                GST_ELEMENT_NAME (element));
+
+            /* update degree */
+            if (new_deg == 0) {
+              /* degree hit 0, add to queue */
+              add_to_queue (bit, peer_element);
+            } else {
+              HASH_SET_DEGREE (bit, peer_element, new_deg);
+            }
+            linked = TRUE;
+          }
+          GST_OBJECT_UNLOCK (peer_element);
+          gst_object_unref (peer_element);
+        }
+        gst_object_unref (peer);
+      }
+    }
+  }
+  if (!linked) {
+    GST_DEBUG_OBJECT (bit->bin, "element %s not linked on any sinkpads",
+        GST_ELEMENT_NAME (element));
+  }
+  GST_OBJECT_UNLOCK (element);
+}
+
+/* find the next best element not handled yet. This is the one
+ * with the lowest non-negative degree */
+static void
+find_element (GstElement * element, GstBinSortIterator * bit)
+{
+  gint degree;
+
+  /* element is already handled */
+  if ((degree = HASH_GET_DEGREE (bit, element)) < 0)
+    return;
+
+  /* first element or element with smaller degree */
+  if (bit->best == NULL || bit->best_deg > degree) {
+    bit->best = element;
+    bit->best_deg = degree;
+  }
+}
+
+/* get next element in iterator. the returned element has the
+ * refcount increased */
+static GstIteratorResult
+gst_bin_sort_iterator_next (GstBinSortIterator * bit, gpointer * result)
+{
+  GstBin *bin = bit->bin;
+
+  /* empty queue, we have to find a next best element */
+  if (g_queue_is_empty (bit->queue)) {
+    GstElement *best;
+
+    bit->best = NULL;
+    bit->best_deg = G_MAXINT;
+    g_list_foreach (bin->children, (GFunc) find_element, bit);
+    if ((best = bit->best)) {
+      if (bit->best_deg != 0) {
+        /* we don't fail on this one yet */
+        GST_WARNING_OBJECT (bin, "loop dected in graph");
+        g_warning ("loop detected in the graph of bin %s!!",
+            GST_ELEMENT_NAME (bin));
+      }
+      /* best unhandled element, schedule as next element */
+      GST_DEBUG_OBJECT (bin, "queue empty, next best: %s",
+          GST_ELEMENT_NAME (best));
+      gst_object_ref (best);
+      HASH_SET_DEGREE (bit, best, -1);
+      *result = best;
+    } else {
+      GST_DEBUG_OBJECT (bin, "queue empty, elements exhausted");
+      /* no more unhandled elements, we are done */
+      return GST_ITERATOR_DONE;
+    }
+  } else {
+    /* everything added to the queue got reffed */
+    *result = g_queue_pop_head (bit->queue);
+  }
+
+  GST_DEBUG_OBJECT (bin, "queue head gives %s", GST_ELEMENT_NAME (*result));
+  /* update degrees of linked elements */
+  update_degree (GST_ELEMENT_CAST (*result), bit);
+
+  return GST_ITERATOR_OK;
+}
+
+/* clear queues, recalculate the degrees and restart. */
+static void
+gst_bin_sort_iterator_resync (GstBinSortIterator * bit)
+{
+  GstBin *bin = bit->bin;
+
+  GST_DEBUG_OBJECT (bin, "resync");
+  clear_queue (bit->queue);
+  /* reset degrees */
+  g_list_foreach (bin->children, (GFunc) reset_degree, bit);
+  /* calc degrees, incrementing */
+  bit->mode = 1;
+  g_list_foreach (bin->children, (GFunc) update_degree, bit);
+  /* for the rest of the function we decrement the degrees */
+  bit->mode = -1;
+}
+
+/* clear queues, unref bin and free iterator. */
+static void
+gst_bin_sort_iterator_free (GstBinSortIterator * bit)
+{
+  GstBin *bin = bit->bin;
+
+  GST_DEBUG_OBJECT (bin, "free");
+  clear_queue (bit->queue);
+  g_queue_free (bit->queue);
+  g_hash_table_destroy (bit->hash);
+  gst_object_unref (bin);
+  g_free (bit);
+}
+
+/* should be called with the bin LOCK held */
+static GstIterator *
+gst_bin_sort_iterator_new (GstBin * bin)
+{
+  GstBinSortIterator *result;
+
+  /* we don't need an ItemFunction because we ref the items in the _next
+   * method already */
+  result = (GstBinSortIterator *)
+      gst_iterator_new (sizeof (GstBinSortIterator),
+      GST_TYPE_ELEMENT,
+      GST_OBJECT_GET_LOCK (bin),
+      &bin->children_cookie,
+      (GstIteratorNextFunction) gst_bin_sort_iterator_next,
+      (GstIteratorItemFunction) NULL,
+      (GstIteratorResyncFunction) gst_bin_sort_iterator_resync,
+      (GstIteratorFreeFunction) gst_bin_sort_iterator_free);
+  result->queue = g_queue_new ();
+  result->hash = g_hash_table_new (NULL, NULL);
+  gst_object_ref (bin);
+  result->bin = bin;
+  gst_bin_sort_iterator_resync (result);
+
+  return (GstIterator *) result;
+}
+
+/**
+ * gst_bin_iterate_sorted:
+ * @bin: a #GstBin
+ *
+ * Gets an iterator for the elements in this bin in topologically
+ * sorted order. This means that the elements are returned from
+ * the most downstream elements (sinks) to the sources.
+ *
+ * This function is used internally to perform the state changes
+ * of the bin elements and for clock selection.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_sorted (GstBin * bin)
+{
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  GST_OBJECT_LOCK (bin);
+  result = gst_bin_sort_iterator_new (bin);
+  GST_OBJECT_UNLOCK (bin);
+
+  return result;
+}
+
+static GstStateChangeReturn
+gst_bin_element_set_state (GstBin * bin, GstElement * element,
+    GstClockTime base_time, GstState current, GstState next)
+{
+  GstStateChangeReturn ret;
+  gboolean locked;
+  GList *found;
+
+  /* peel off the locked flag */
+  GST_OBJECT_LOCK (element);
+  locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
+  /* get previous state return */
+  ret = GST_STATE_RETURN (element);
+  GST_OBJECT_UNLOCK (element);
+
+  /* skip locked elements */
+  if (G_UNLIKELY (locked))
+    goto locked;
+
+  /* if the element was no preroll, just start changing the state regardless
+   * if it had async elements (in the case of a bin) because they won't preroll
+   * anyway. */
+  if (G_UNLIKELY (ret == GST_STATE_CHANGE_NO_PREROLL)) {
+    GST_DEBUG_OBJECT (element, "element is NO_PREROLL, ignore async elements");
+    goto no_preroll;
+  }
+
+  GST_OBJECT_LOCK (bin);
+  /* the element was busy with an upwards async state change, we must wait for
+   * an ASYNC_DONE message before we attemp to change the state. */
+  if ((found =
+          find_message (bin, GST_OBJECT_CAST (element),
+              GST_MESSAGE_ASYNC_START))) {
+#ifndef GST_DISABLE_GST_DEBUG
+    GstMessage *message = GST_MESSAGE_CAST (found->data);
+
+    GST_DEBUG_OBJECT (element, "element message %p, %s async busy",
+        message, GST_ELEMENT_NAME (GST_MESSAGE_SRC (message)));
+#endif
+    /* only wait for upward state changes */
+    if (next > current) {
+      /* We found an async element check if we can force its state to change or
+       * if we have to wait for it to preroll. */
+      if (G_UNLIKELY (!enable_latency)) {
+        g_warning ("Future versions of GStreamer will wait for element \"%s\"\n"
+            "\tto preroll in order to perform correct latency calculations.\n"
+            "\tPlease verify that the application continues to work correctly by\n"
+            "\tsetting the environment variable GST_COMPAT to a value containing\n"
+            "\tthe string 'live-preroll'.", GST_ELEMENT_NAME (element));
+        goto no_latency;
+      }
+      goto was_busy;
+    }
+  }
+no_latency:
+  GST_OBJECT_UNLOCK (bin);
+
+no_preroll:
+  GST_DEBUG_OBJECT (bin,
+      "setting element %s to %s, base_time %" GST_TIME_FORMAT,
+      GST_ELEMENT_NAME (element), gst_element_state_get_name (next),
+      GST_TIME_ARGS (base_time));
+
+  /* set base_time on child */
+  gst_element_set_base_time (element, base_time);
+
+  /* change state */
+  ret = gst_element_set_state (element, next);
+
+  return ret;
+
+locked:
+  {
+    GST_DEBUG_OBJECT (element,
+        "element is locked, return previous return %s",
+        gst_element_state_change_return_get_name (ret));
+    return ret;
+  }
+was_busy:
+  {
+    GST_DEBUG_OBJECT (element, "element was busy, delaying state change");
+    GST_OBJECT_UNLOCK (bin);
+    return GST_STATE_CHANGE_ASYNC;
+  }
+}
+
+/* gst_iterator_fold functions for pads_activate
+ * Note how we don't stop the iterator when we fail an activation. This is
+ * probably a FIXME since when one pad activation fails, we don't want to
+ * continue our state change. */
+static gboolean
+activate_pads (GstPad * pad, GValue * ret, gboolean * active)
+{
+  if (!gst_pad_set_active (pad, *active))
+    g_value_set_boolean (ret, FALSE);
+  else if (!*active)
+    gst_pad_set_caps (pad, NULL);
+
+  /* unref the object that was reffed for us by _fold */
+  gst_object_unref (pad);
+  return TRUE;
+}
+
+/* returns false on error or early cutout (will never happen because the fold
+ * function always returns TRUE, see FIXME above) of the fold, true if all
+ * pads in @iter were (de)activated successfully. */
+static gboolean
+iterator_activate_fold_with_resync (GstIterator * iter, gpointer user_data)
+{
+  GstIteratorResult ires;
+  GValue ret = { 0 };
+
+  /* no need to unset this later, it's just a boolean */
+  g_value_init (&ret, G_TYPE_BOOLEAN);
+  g_value_set_boolean (&ret, TRUE);
+
+  while (1) {
+    ires = gst_iterator_fold (iter, (GstIteratorFoldFunction) activate_pads,
+        &ret, user_data);
+    switch (ires) {
+      case GST_ITERATOR_RESYNC:
+        /* need to reset the result again */
+        g_value_set_boolean (&ret, TRUE);
+        gst_iterator_resync (iter);
+        break;
+      case GST_ITERATOR_DONE:
+        /* all pads iterated, return collected value */
+        goto done;
+      default:
+        /* iterator returned _ERROR or premature end with _OK,
+         * mark an error and exit */
+        g_value_set_boolean (&ret, FALSE);
+        goto done;
+    }
+  }
+done:
+  /* return collected value */
+  return g_value_get_boolean (&ret);
+}
+
+/* is called with STATE_LOCK
+ */
+static gboolean
+gst_bin_src_pads_activate (GstBin * bin, gboolean active)
+{
+  GstIterator *iter;
+  gboolean fold_ok;
+
+  GST_DEBUG_OBJECT (bin, "src_pads_activate with active %d", active);
+
+  iter = gst_element_iterate_src_pads ((GstElement *) bin);
+  fold_ok = iterator_activate_fold_with_resync (iter, &active);
+  gst_iterator_free (iter);
+  if (G_UNLIKELY (!fold_ok))
+    goto failed;
+
+  GST_DEBUG_OBJECT (bin, "pads_activate successful");
+
+  return TRUE;
+
+  /* ERRORS */
+failed:
+  {
+    GST_DEBUG_OBJECT (bin, "source pads_activate failed");
+    return FALSE;
+  }
+}
+
+/* do latency correction. We do a latency query on the bin, and then send a
+ * LATENCY event on the elements fo configure them */
+static gboolean
+do_bin_latency (GstElement * element)
+{
+  GstQuery *query;
+  GstClockTime min_latency, max_latency;
+  gboolean res;
+
+  GST_DEBUG_OBJECT (element, "querying latency");
+
+  query = gst_query_new_latency ();
+  if ((res = gst_element_query (element, query))) {
+    gboolean live;
+
+    gst_query_parse_latency (query, &live, &min_latency, &max_latency);
+
+    GST_DEBUG_OBJECT (element,
+        "got min latency %" GST_TIME_FORMAT ", max latency %"
+        GST_TIME_FORMAT ", live %d", GST_TIME_ARGS (min_latency),
+        GST_TIME_ARGS (max_latency), live);
+
+    if (max_latency < min_latency) {
+      /* this is an impossible situation, some parts of the pipeline might not
+       * work correctly. We post a warning for now. */
+      GST_ELEMENT_WARNING (element, CORE, CLOCK, (NULL),
+          ("Impossible to configure latency: max %" GST_TIME_FORMAT " < min %"
+              GST_TIME_FORMAT ". Add queues or other buffering elements.",
+              GST_TIME_ARGS (max_latency), GST_TIME_ARGS (min_latency)));
+    }
+
+    /* configure latency on elements */
+    res = gst_element_send_event (element, gst_event_new_latency (min_latency));
+    if (res) {
+      GST_INFO_OBJECT (element, "configured latency of %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (min_latency));
+    } else {
+      GST_WARNING_OBJECT (element,
+          "failed to configure latency of %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (min_latency));
+      GST_ELEMENT_WARNING (element, CORE, CLOCK, (NULL),
+          ("Failed to configure latency of %" GST_TIME_FORMAT,
+              GST_TIME_ARGS (min_latency)));
+    }
+  } else {
+    /* this is not a real problem, we just don't configure any latency. */
+    GST_WARNING_OBJECT (element, "failed to query latency");
+  }
+  gst_query_unref (query);
+
+  return res;
+}
+
+static GstStateChangeReturn
+gst_bin_change_state_func (GstElement * element, GstStateChange transition)
+{
+  GstBin *bin;
+  GstStateChangeReturn ret;
+  GstState current, next;
+  gboolean have_async;
+  gboolean have_no_preroll;
+  GstClockTime base_time;
+  GstIterator *it;
+  gboolean done;
+
+  /* we don't need to take the STATE_LOCK, it is already taken */
+  current = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
+  next = (GstState) GST_STATE_TRANSITION_NEXT (transition);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
+      "changing state of children from %s to %s",
+      gst_element_state_get_name (current), gst_element_state_get_name (next));
+
+  bin = GST_BIN_CAST (element);
+
+  switch (next) {
+    case GST_STATE_PLAYING:
+    {
+      gboolean toplevel;
+
+      GST_OBJECT_LOCK (bin);
+      toplevel = BIN_IS_TOPLEVEL (bin);
+      GST_OBJECT_UNLOCK (bin);
+
+      if (toplevel)
+        do_bin_latency (element);
+      break;
+    }
+    case GST_STATE_PAUSED:
+      /* Clear EOS list on next PAUSED */
+      GST_OBJECT_LOCK (bin);
+      GST_DEBUG_OBJECT (element, "clearing EOS elements");
+      bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
+      GST_OBJECT_UNLOCK (bin);
+      if (current == GST_STATE_READY)
+        if (!(gst_bin_src_pads_activate (bin, TRUE)))
+          goto activate_failure;
+      break;
+    case GST_STATE_READY:
+      /* Clear message list on next READY */
+      GST_OBJECT_LOCK (bin);
+      GST_DEBUG_OBJECT (element, "clearing all cached messages");
+      bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
+      GST_OBJECT_UNLOCK (bin);
+      if (current == GST_STATE_PAUSED)
+        if (!(gst_bin_src_pads_activate (bin, FALSE)))
+          goto activate_failure;
+      break;
+    case GST_STATE_NULL:
+      if (current == GST_STATE_READY)
+        if (!(gst_bin_src_pads_activate (bin, FALSE)))
+          goto activate_failure;
+      break;
+    default:
+      break;
+  }
+
+  /* this flag is used to make the async state changes return immediatly. We
+   * don't want them to interfere with this state change */
+  GST_OBJECT_LOCK (bin);
+  bin->polling = TRUE;
+  GST_OBJECT_UNLOCK (bin);
+
+  /* iterate in state change order */
+  it = gst_bin_iterate_sorted (bin);
+
+  /* mark if we've seen an ASYNC element in the bin when we did a state change.
+   * Note how we don't reset this value when a resync happens, the reason being
+   * that the async element posted ASYNC_START and we want to post ASYNC_DONE
+   * even after a resync when the async element is gone */
+  have_async = FALSE;
+
+restart:
+  /* take base_time */
+  base_time = gst_element_get_base_time (element);
+
+  have_no_preroll = FALSE;
+
+  done = FALSE;
+  while (!done) {
+    gpointer data;
+
+    switch (gst_iterator_next (it, &data)) {
+      case GST_ITERATOR_OK:
+      {
+        GstElement *child;
+
+        child = GST_ELEMENT_CAST (data);
+
+        /* set state and base_time now */
+        ret = gst_bin_element_set_state (bin, child, base_time, current, next);
+
+        switch (ret) {
+          case GST_STATE_CHANGE_SUCCESS:
+            GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
+                "child '%s' changed state to %d(%s) successfully",
+                GST_ELEMENT_NAME (child), next,
+                gst_element_state_get_name (next));
+            break;
+          case GST_STATE_CHANGE_ASYNC:
+          {
+            GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
+                "child '%s' is changing state asynchronously to %s",
+                GST_ELEMENT_NAME (child), gst_element_state_get_name (next));
+            have_async = TRUE;
+            break;
+          }
+          case GST_STATE_CHANGE_FAILURE:
+            GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
+                "child '%s' failed to go to state %d(%s)",
+                GST_ELEMENT_NAME (child),
+                next, gst_element_state_get_name (next));
+            gst_object_unref (child);
+            goto done;
+          case GST_STATE_CHANGE_NO_PREROLL:
+            GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
+                "child '%s' changed state to %d(%s) successfully without preroll",
+                GST_ELEMENT_NAME (child), next,
+                gst_element_state_get_name (next));
+            have_no_preroll = TRUE;
+            break;
+          default:
+            g_assert_not_reached ();
+            break;
+        }
+        gst_object_unref (child);
+        break;
+      }
+      case GST_ITERATOR_RESYNC:
+        GST_CAT_DEBUG (GST_CAT_STATES, "iterator doing resync");
+        gst_iterator_resync (it);
+        goto restart;
+      default:
+      case GST_ITERATOR_DONE:
+        GST_CAT_DEBUG (GST_CAT_STATES, "iterator done");
+        done = TRUE;
+        break;
+    }
+  }
+
+  ret = parent_class->change_state (element, transition);
+  if (G_UNLIKELY (ret == GST_STATE_CHANGE_FAILURE))
+    goto done;
+
+  if (have_no_preroll) {
+    ret = GST_STATE_CHANGE_NO_PREROLL;
+  } else if (have_async) {
+    ret = GST_STATE_CHANGE_ASYNC;
+  }
+
+done:
+  gst_iterator_free (it);
+
+  GST_OBJECT_LOCK (bin);
+  bin->polling = FALSE;
+  if (ret != GST_STATE_CHANGE_ASYNC) {
+    /* no element returned ASYNC, we can just complete. */
+    GST_DEBUG_OBJECT (bin, "no async elements");
+    goto state_end;
+  }
+  /* when we get here an ASYNC element was found */
+  if (GST_STATE_TARGET (bin) <= GST_STATE_READY) {
+    /* we ignore ASYNC state changes when we go to READY or NULL */
+    GST_DEBUG_OBJECT (bin, "target state %s <= READY",
+        gst_element_state_get_name (GST_STATE_TARGET (bin)));
+    goto state_end;
+  }
+
+  GST_DEBUG_OBJECT (bin, "check async elements");
+  /* check if all elements managed to commit their state already */
+  if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
+    /* nothing found, remove all old ASYNC_DONE messages. This can happen when
+     * all the elements commited their state while we were doing the state
+     * change. We will still return ASYNC for consistency but we commit the
+     * state already so that a _get_state() will return immediatly. */
+    bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
+
+    GST_DEBUG_OBJECT (bin, "async elements commited");
+    bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS);
+  }
+
+state_end:
+  GST_OBJECT_UNLOCK (bin);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
+      "done changing bin's state from %s to %s, now in %s, ret %s",
+      gst_element_state_get_name (current),
+      gst_element_state_get_name (next),
+      gst_element_state_get_name (GST_STATE (element)),
+      gst_element_state_change_return_get_name (ret));
+
+  return ret;
+
+  /* ERRORS */
+activate_failure:
+  {
+    GST_CAT_WARNING_OBJECT (GST_CAT_STATES, element,
+        "failure (de)activating src pads");
+    return GST_STATE_CHANGE_FAILURE;
+  }
+}
+
+/*
+ * This function is a utility event handler for seek events.
+ * It will send the event to all sinks or sources depending on the
+ * event-direction.
+ *
+ * Applications are free to override this behaviour and
+ * implement their own seek handler, but this will work for
+ * pretty much all cases in practice.
+ */
+static gboolean
+gst_bin_send_event (GstElement * element, GstEvent * event)
+{
+  GstBin *bin = GST_BIN (element);
+  GstIterator *iter;
+  gboolean res = TRUE;
+  gboolean done = FALSE;
+
+  if (GST_EVENT_IS_DOWNSTREAM (event)) {
+    iter = gst_bin_iterate_sources (bin);
+    GST_DEBUG_OBJECT (bin, "Sending %s event to src children",
+        GST_EVENT_TYPE_NAME (event));
+  } else {
+    iter = gst_bin_iterate_sinks (bin);
+    GST_DEBUG_OBJECT (bin, "Sending %s event to sink children",
+        GST_EVENT_TYPE_NAME (event));
+  }
+
+  while (!done) {
+    gpointer data;
+
+    switch (gst_iterator_next (iter, &data)) {
+      case GST_ITERATOR_OK:
+      {
+        GstElement *child;
+
+        gst_event_ref (event);
+        child = GST_ELEMENT_CAST (data);
+        res &= gst_element_send_event (child, event);
+        gst_object_unref (child);
+        break;
+      }
+      case GST_ITERATOR_RESYNC:
+        gst_iterator_resync (iter);
+        res = TRUE;
+        break;
+      case GST_ITERATOR_DONE:
+        done = TRUE;
+        break;
+      case GST_ITERATOR_ERROR:
+        g_assert_not_reached ();
+        break;
+    }
+  }
+  gst_iterator_free (iter);
+  gst_event_unref (event);
+
+  return res;
+}
+
+/* this is the function called by the threadpool. When async elements commit
+ * their state, this function will attempt to bring the bin to the next state.
+ */
+static void
+gst_bin_continue_func (BinContinueData * data)
+{
+  GstBin *bin;
+  GstState current, next, pending;
+  GstStateChange transition;
+  GstStateChangeReturn ret;
+
+  bin = data->bin;
+  pending = data->pending;
+
+  GST_DEBUG_OBJECT (bin, "waiting for state lock");
+  GST_STATE_LOCK (bin);
+
+  GST_DEBUG_OBJECT (bin, "doing state continue");
+  GST_OBJECT_LOCK (bin);
+
+  /* if a new state change happened after this thread was scheduled, we return
+   * immediatly. */
+  if (data->cookie != GST_ELEMENT_CAST (bin)->state_cookie)
+    goto interrupted;
+
+  current = GST_STATE (bin);
+  next = GST_STATE_GET_NEXT (current, pending);
+  transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
+
+  GST_STATE_NEXT (bin) = next;
+  /* mark busy */
+  GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
+  GST_OBJECT_UNLOCK (bin);
+
+  GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
+      "continue state change %s to %s, final %s",
+      gst_element_state_get_name (current),
+      gst_element_state_get_name (next), gst_element_state_get_name (pending));
+
+  ret = gst_element_change_state (GST_ELEMENT_CAST (bin), transition);
+
+  GST_STATE_UNLOCK (bin);
+  GST_DEBUG_OBJECT (bin, "state continue done");
+  gst_object_unref (bin);
+  g_free (data);
+  return;
+
+interrupted:
+  {
+    GST_OBJECT_UNLOCK (bin);
+    GST_STATE_UNLOCK (bin);
+    GST_DEBUG_OBJECT (bin, "state continue aborted due to intervening change");
+    gst_object_unref (bin);
+    g_free (data);
+    return;
+  }
+}
+
+static GstBusSyncReply
+bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
+{
+  GstBinClass *bclass;
+
+  bclass = GST_BIN_GET_CLASS (bin);
+  if (bclass->handle_message)
+    bclass->handle_message (bin, message);
+  else
+    gst_message_unref (message);
+
+  return GST_BUS_DROP;
+}
+
+static void
+bin_push_state_continue (BinContinueData * data)
+{
+  GstBinClass *klass;
+  GstBin *bin;
+
+  /* ref was taken */
+  bin = data->bin;
+  klass = GST_BIN_GET_CLASS (bin);
+
+  GST_DEBUG_OBJECT (bin, "pushing continue on thread pool");
+  g_thread_pool_push (klass->pool, data, NULL);
+}
+
+/* an element started an async state change, if we were not busy with a state
+ * change, we perform a lost state.
+ * This function is called with the OBJECT lock.
+ */
+static void
+bin_handle_async_start (GstBin * bin, gboolean new_base_time)
+{
+  GstState old_state, new_state;
+  gboolean toplevel;
+  GstMessage *amessage = NULL;
+
+  if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
+    goto had_error;
+
+  /* get our toplevel state */
+  toplevel = BIN_IS_TOPLEVEL (bin);
+
+  /* prepare an ASYNC_START message, we always post the start message even if we
+   * are busy with a state change or when we are NO_PREROLL. */
+  if (!toplevel)
+    /* non toplevel bin, prepare async-start for the parent */
+    amessage =
+        gst_message_new_async_start (GST_OBJECT_CAST (bin), new_base_time);
+
+  if (bin->polling || GST_STATE_PENDING (bin) != GST_STATE_VOID_PENDING)
+    goto was_busy;
+
+  /* async starts are ignored when we are NO_PREROLL */
+  if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_NO_PREROLL)
+    goto was_no_preroll;
+
+
+  old_state = GST_STATE (bin);
+
+  /* when we PLAYING we go back to PAUSED, when preroll happens, we go back to
+   * PLAYING after optionally redistributing the base_time. */
+  if (old_state > GST_STATE_PAUSED)
+    new_state = GST_STATE_PAUSED;
+  else
+    new_state = old_state;
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
+      "lost state of %s, new %s", gst_element_state_get_name (old_state),
+      gst_element_state_get_name (new_state));
+
+  GST_STATE (bin) = new_state;
+  GST_STATE_NEXT (bin) = new_state;
+  GST_STATE_PENDING (bin) = new_state;
+  GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
+  GST_OBJECT_UNLOCK (bin);
+
+  /* post message */
+  gst_element_post_message (GST_ELEMENT_CAST (bin),
+      gst_message_new_state_changed (GST_OBJECT_CAST (bin),
+          new_state, new_state, new_state));
+
+post_start:
+  if (amessage) {
+    /* post our ASYNC_START. */
+    GST_DEBUG_OBJECT (bin, "posting ASYNC_START to parent");
+    gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
+  }
+  GST_OBJECT_LOCK (bin);
+
+  return;
+
+had_error:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
+    return;
+  }
+was_busy:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
+    GST_OBJECT_UNLOCK (bin);
+    goto post_start;
+  }
+was_no_preroll:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "ignoring, we are NO_PREROLL");
+    GST_OBJECT_UNLOCK (bin);
+    goto post_start;
+  }
+}
+
+/* this function is called when there are no more async elements in the bin. We
+ * post a state changed message and an ASYNC_DONE message.
+ * This function is called with the OBJECT lock.
+ */
+static void
+bin_handle_async_done (GstBin * bin, GstStateChangeReturn ret)
+{
+  GstState current, pending, target;
+  GstStateChangeReturn old_ret;
+  GstState old_state, old_next;
+  gboolean toplevel;
+  GstMessage *smessage = NULL, *amessage = NULL;
+  BinContinueData *cont = NULL;
+
+  if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
+    goto had_error;
+
+  pending = GST_STATE_PENDING (bin);
+
+  if (bin->polling)
+    goto was_busy;
+
+  /* check if there is something to commit */
+  if (pending == GST_STATE_VOID_PENDING)
+    goto nothing_pending;
+
+  old_ret = GST_STATE_RETURN (bin);
+  GST_STATE_RETURN (bin) = ret;
+
+  /* move to the next target state */
+  target = GST_STATE_TARGET (bin);
+  pending = GST_STATE_PENDING (bin) = target;
+
+  amessage = gst_message_new_async_done (GST_OBJECT_CAST (bin));
+
+  old_state = GST_STATE (bin);
+  /* this is the state we should go to next */
+  old_next = GST_STATE_NEXT (bin);
+
+  if (old_next != GST_STATE_PLAYING) {
+    GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
+        "committing state from %s to %s, old pending %s",
+        gst_element_state_get_name (old_state),
+        gst_element_state_get_name (old_next),
+        gst_element_state_get_name (pending));
+
+    /* update current state */
+    current = GST_STATE (bin) = old_next;
+  } else {
+    current = old_state;
+  }
+
+  /* get our toplevel state */
+  toplevel = BIN_IS_TOPLEVEL (bin);
+
+  /* see if we reached the final state. If we are not toplevel, we also have to
+   * stop here, the parent will continue our state. */
+  if ((pending == current) || !toplevel) {
+    GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
+        "completed state change, pending VOID");
+
+    /* mark VOID pending */
+    pending = GST_STATE_VOID_PENDING;
+    GST_STATE_PENDING (bin) = pending;
+    GST_STATE_NEXT (bin) = GST_STATE_VOID_PENDING;
+  } else {
+    GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
+        "continue state change, pending %s",
+        gst_element_state_get_name (pending));
+
+    cont = g_new0 (BinContinueData, 1);
+
+    /* ref to the bin */
+    cont->bin = gst_object_ref (bin);
+    /* cookie to detect concurrent state change */
+    cont->cookie = GST_ELEMENT_CAST (bin)->state_cookie;
+    /* pending target state */
+    cont->pending = pending;
+    /* mark busy */
+    GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
+    GST_STATE_NEXT (bin) = pending;
+  }
+
+  if (old_next != GST_STATE_PLAYING) {
+    if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
+      smessage = gst_message_new_state_changed (GST_OBJECT_CAST (bin),
+          old_state, old_next, pending);
+    }
+  }
+  GST_OBJECT_UNLOCK (bin);
+
+  if (smessage) {
+    GST_DEBUG_OBJECT (bin, "posting state change message");
+    gst_element_post_message (GST_ELEMENT_CAST (bin), smessage);
+  }
+  if (amessage) {
+    /* post our combined ASYNC_DONE when all is ASYNC_DONE. */
+    GST_DEBUG_OBJECT (bin, "posting ASYNC_DONE to parent");
+    gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
+  }
+
+  GST_OBJECT_LOCK (bin);
+  if (cont) {
+    /* toplevel, start continue state */
+    GST_DEBUG_OBJECT (bin, "all async-done, starting state continue");
+    bin_push_state_continue (cont);
+  } else {
+    GST_DEBUG_OBJECT (bin, "state change complete");
+    GST_STATE_BROADCAST (bin);
+  }
+  return;
+
+had_error:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
+    return;
+  }
+was_busy:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
+    return;
+  }
+nothing_pending:
+  {
+    GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "nothing pending");
+    return;
+  }
+}
+
+/* handle child messages:
+ *
+ * This method is called synchronously when a child posts a message on
+ * the internal bus.
+ *
+ * GST_MESSAGE_EOS: This message is only posted by sinks
+ *     in the PLAYING state. If all sinks posted the EOS message, post
+ *     one upwards.
+ *
+ * GST_MESSAGE_STATE_DIRTY: Deprecated
+ *
+ * GST_MESSAGE_SEGMENT_START: just collect, never forward upwards. If an
+ *     element posts segment_start twice, only the last message is kept.
+ *
+ * GST_MESSAGE_SEGMENT_DONE: replace SEGMENT_START message from same poster
+ *     with the segment_done message. If there are no more segment_start
+ *     messages, post segment_done message upwards.
+ *
+ * GST_MESSAGE_DURATION: remove all previously cached duration messages.
+ *     Whenever someone performs a duration query on the bin, we store the
+ *     result so we can answer it quicker the next time. Any element that
+ *     changes its duration marks our cached values invalid.
+ *     This message is also posted upwards. This is currently disabled
+ *     because too many elements don't post DURATION messages when the
+ *     duration changes.
+ *
+ * GST_MESSAGE_CLOCK_LOST: This message is posted by an element when it
+ *     can no longer provide a clock. The default bin behaviour is to
+ *     check if the lost clock was the one provided by the bin. If so and
+ *     we are currently in the PLAYING state, we forward the message to
+ *     our parent.
+ *     This message is also generated when we remove a clock provider from
+ *     a bin. If this message is received by the application, it should
+ *     PAUSE the pipeline and set it back to PLAYING to force a new clock
+ *     and a new base_time distribution.
+ *
+ * GST_MESSAGE_CLOCK_PROVIDE: This message is generated when an element
+ *     can provide a clock. This mostly happens when we add a new clock
+ *     provider to the bin. The default behaviour of the bin is to mark the
+ *     currently selected clock as dirty, which will perform a clock
+ *     recalculation the next time we are asked to provide a clock.
+ *     This message is never sent to the application but is forwarded to
+ *     the parent.
+ *
+ * GST_MESSAGE_ASYNC_START: Create an internal ELEMENT message that stores
+ *     the state of the element and the fact that the element will need a
+ *     new base_time. This message is not forwarded to the application.
+ *
+ * GST_MESSAGE_ASYNC_DONE: Find the internal ELEMENT message we kept for the
+ *     element when it posted ASYNC_START. If all elements are done, post a
+ *     ASYNC_DONE message to the parent.
+ *
+ * OTHER: post upwards.
+ */
+static void
+gst_bin_handle_message_func (GstBin * bin, GstMessage * message)
+{
+  GstObject *src;
+  GstMessageType type;
+
+  src = GST_MESSAGE_SRC (message);
+  type = GST_MESSAGE_TYPE (message);
+
+// Message src can be NULL
+  if(src)
+  GST_DEBUG_OBJECT (bin, "[msg %p] handling child %s message of type %s",
+      message, GST_ELEMENT_NAME (src), GST_MESSAGE_TYPE_NAME (message));
+  else
+  GST_DEBUG_OBJECT (bin, "[msg %p] handling child %s message of type %s",
+            message, "Null ", GST_MESSAGE_TYPE_NAME (message));
+  
+  switch (type) {
+    case GST_MESSAGE_EOS:
+    {
+      gboolean eos;
+
+      /* collect all eos messages from the children */
+      GST_OBJECT_LOCK (bin);
+      bin_replace_message (bin, message, GST_MESSAGE_EOS);
+      eos = is_eos (bin);
+      GST_OBJECT_UNLOCK (bin);
+
+      /* if we are completely EOS, we forward an EOS message */
+      if (eos) {
+        GST_DEBUG_OBJECT (bin, "all sinks posted EOS");
+        gst_element_post_message (GST_ELEMENT_CAST (bin),
+            gst_message_new_eos (GST_OBJECT_CAST (bin)));
+      }
+      break;
+    }
+    case GST_MESSAGE_STATE_DIRTY:
+    {
+      GST_WARNING_OBJECT (bin, "received deprecated STATE_DIRTY message");
+
+      /* free message */
+      gst_message_unref (message);
+      break;
+    }
+    case GST_MESSAGE_SEGMENT_START:
+      GST_OBJECT_LOCK (bin);
+      /* replace any previous segment_start message from this source
+       * with the new segment start message */
+      bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
+      GST_OBJECT_UNLOCK (bin);
+      break;
+    case GST_MESSAGE_SEGMENT_DONE:
+    {
+      gboolean post = FALSE;
+      GstFormat format;
+      gint64 position;
+
+      gst_message_parse_segment_done (message, &format, &position);
+
+      GST_OBJECT_LOCK (bin);
+      bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
+      /* if there are no more segment_start messages, everybody posted
+       * a segment_done and we can post one on the bus. */
+
+      /* we don't care who still has a pending segment start */
+      if (!find_message (bin, NULL, GST_MESSAGE_SEGMENT_START)) {
+        /* nothing found */
+        post = TRUE;
+        /* remove all old segment_done messages */
+        bin_remove_messages (bin, NULL, GST_MESSAGE_SEGMENT_DONE);
+      }
+      GST_OBJECT_UNLOCK (bin);
+      if (post) {
+        /* post segment done with latest format and position. */
+        gst_element_post_message (GST_ELEMENT_CAST (bin),
+            gst_message_new_segment_done (GST_OBJECT_CAST (bin),
+                format, position));
+      }
+      break;
+    }
+    case GST_MESSAGE_DURATION:
+    {
+      /* remove all cached duration messages, next time somebody asks
+       * for duration, we will recalculate. */
+      GST_OBJECT_LOCK (bin);
+      bin_remove_messages (bin, NULL, GST_MESSAGE_DURATION);
+      GST_OBJECT_UNLOCK (bin);
+      goto forward;
+    }
+    case GST_MESSAGE_CLOCK_LOST:
+    {
+      GstClock **provided_clock_p;
+      GstElement **clock_provider_p;
+      gboolean playing, provided, forward;
+      GstClock *clock;
+
+      gst_message_parse_clock_lost (message, &clock);
+
+      GST_OBJECT_LOCK (bin);
+      bin->clock_dirty = TRUE;
+      /* if we lost the clock that we provided, post to parent but
+       * only if we are PLAYING. */
+      provided = (clock == bin->provided_clock);
+      playing = (GST_STATE (bin) == GST_STATE_PLAYING);
+      forward = playing & provided;
+      if (provided) {
+        GST_DEBUG_OBJECT (bin,
+            "Lost clock %" GST_PTR_FORMAT " provided by %" GST_PTR_FORMAT,
+            bin->provided_clock, bin->clock_provider);
+        provided_clock_p = &bin->provided_clock;
+        clock_provider_p = &bin->clock_provider;
+        gst_object_replace ((GstObject **) provided_clock_p, NULL);
+        gst_object_replace ((GstObject **) clock_provider_p, NULL);
+      }
+      GST_DEBUG_OBJECT (bin, "provided %d, playing %d, forward %d",
+          provided, playing, forward);
+      GST_OBJECT_UNLOCK (bin);
+
+      if (forward)
+        goto forward;
+
+      /* free message */
+      gst_message_unref (message);
+      break;
+    }
+    case GST_MESSAGE_CLOCK_PROVIDE:
+    {
+      gboolean forward;
+
+      GST_OBJECT_LOCK (bin);
+      bin->clock_dirty = TRUE;
+      /* a new clock is available, post to parent but not
+       * to the application */
+      forward = GST_OBJECT_PARENT (bin) != NULL;
+      GST_OBJECT_UNLOCK (bin);
+
+      if (forward)
+        goto forward;
+
+      /* free message */
+      gst_message_unref (message);
+      break;
+    }
+    case GST_MESSAGE_ASYNC_START:
+    {
+      gboolean new_base_time;
+      GstState target;
+	if(src)
+      GST_DEBUG_OBJECT (bin, "ASYNC_START message %p, %s", message,
+          GST_OBJECT_NAME (src));
+	else
+	GST_DEBUG_OBJECT (bin, "ASYNC_START message %p, %s", message,
+          "Null Source");
+
+      gst_message_parse_async_start (message, &new_base_time);
+
+      GST_OBJECT_LOCK (bin);
+      /* we ignore the message if we are going to <= READY */
+      target = GST_STATE_TARGET (bin);
+      if (target <= GST_STATE_READY)
+        goto ignore_start_message;
+
+      /* takes ownership of the message */
+      bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
+
+      bin_handle_async_start (bin, new_base_time);
+      GST_OBJECT_UNLOCK (bin);
+      break;
+
+    ignore_start_message:
+      {
+        GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
+            gst_element_state_get_name (target));
+        GST_OBJECT_UNLOCK (bin);
+        gst_message_unref (message);
+        break;
+      }
+    }
+    case GST_MESSAGE_ASYNC_DONE:
+    {
+      GstState target;
+	  
+	  if(src)
+      GST_DEBUG_OBJECT (bin, "ASYNC_DONE message %p, %s", message,
+          GST_OBJECT_NAME (src));
+	  else
+	  GST_DEBUG_OBJECT (bin, "ASYNC_DONE message %p, %s", message,
+          "Null Source");
+
+      GST_OBJECT_LOCK (bin);
+      target = GST_STATE_TARGET (bin);
+      /* ignore messages if we are shutting down */
+      if (target <= GST_STATE_READY)
+        goto ignore_done_message;
+
+      bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
+      /* if there are no more ASYNC_START messages, everybody posted
+       * a ASYNC_DONE and we can post one on the bus. When checking, we
+       * don't care who still has a pending ASYNC_START */
+      if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
+        /* nothing found, remove all old ASYNC_DONE messages */
+        bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
+
+        GST_DEBUG_OBJECT (bin, "async elements commited");
+        bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS);
+      }
+      GST_OBJECT_UNLOCK (bin);
+      break;
+
+    ignore_done_message:
+      {
+        GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
+            gst_element_state_get_name (target));
+        GST_OBJECT_UNLOCK (bin);
+        gst_message_unref (message);
+        break;
+      }
+    }
+    default:
+      goto forward;
+  }
+  return;
+
+forward:
+  {
+    /* Send all other messages upward */
+    GST_DEBUG_OBJECT (bin, "posting message upward");
+    gst_element_post_message (GST_ELEMENT_CAST (bin), message);
+    return;
+  }
+}
+
+/* generic struct passed to all query fold methods */
+typedef struct
+{
+  GstQuery *query;
+  gint64 min;
+  gint64 max;
+  gboolean live;
+} QueryFold;
+
+typedef void (*QueryInitFunction) (GstBin * bin, QueryFold * fold);
+typedef void (*QueryDoneFunction) (GstBin * bin, QueryFold * fold);
+
+/* for duration/position we collect all durations/positions and take
+ * the MAX of all valid results */
+static void
+bin_query_min_max_init (GstBin * bin, QueryFold * fold)
+{
+  fold->min = 0;
+  fold->max = -1;
+  fold->live = FALSE;
+}
+
+static gboolean
+bin_query_duration_fold (GstElement * item, GValue * ret, QueryFold * fold)
+{
+  if (gst_element_query (item, fold->query)) {
+    gint64 duration;
+
+    g_value_set_boolean (ret, TRUE);
+
+    gst_query_parse_duration (fold->query, NULL, &duration);
+
+    GST_DEBUG_OBJECT (item, "got duration %" G_GINT64_FORMAT, duration);
+
+    if (duration > fold->max)
+      fold->max = duration;
+  }
+
+  gst_object_unref (item);
+  return TRUE;
+}
+static void
+bin_query_duration_done (GstBin * bin, QueryFold * fold)
+{
+  GstFormat format;
+
+  gst_query_parse_duration (fold->query, &format, NULL);
+  /* store max in query result */
+  gst_query_set_duration (fold->query, format, fold->max);
+
+  GST_DEBUG_OBJECT (bin, "max duration %" G_GINT64_FORMAT, fold->max);
+
+#ifdef DURATION_CACHING
+  /* and cache now */
+  GST_OBJECT_LOCK (bin);
+  bin->messages = g_list_prepend (bin->messages,
+      gst_message_new_duration (GST_OBJECT_CAST (bin), format, fold->max));
+  GST_OBJECT_UNLOCK (bin);
+#endif
+}
+
+static gboolean
+bin_query_position_fold (GstElement * item, GValue * ret, QueryFold * fold)
+{
+  if (gst_element_query (item, fold->query)) {
+    gint64 position;
+
+    g_value_set_boolean (ret, TRUE);
+
+    gst_query_parse_position (fold->query, NULL, &position);
+
+    GST_DEBUG_OBJECT (item, "got position %" G_GINT64_FORMAT, position);
+
+    if (position > fold->max)
+      fold->max = position;
+  }
+
+  gst_object_unref (item);
+  return TRUE;
+}
+static void
+bin_query_position_done (GstBin * bin, QueryFold * fold)
+{
+  GstFormat format;
+
+  gst_query_parse_position (fold->query, &format, NULL);
+  /* store max in query result */
+  gst_query_set_position (fold->query, format, fold->max);
+
+  GST_DEBUG_OBJECT (bin, "max position %" G_GINT64_FORMAT, fold->max);
+}
+
+static gboolean
+bin_query_latency_fold (GstElement * item, GValue * ret, QueryFold * fold)
+{
+  if (gst_element_query (item, fold->query)) {
+    GstClockTime min, max;
+    gboolean live;
+
+    gst_query_parse_latency (fold->query, &live, &min, &max);
+
+    GST_DEBUG_OBJECT (item,
+        "got latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
+        ", live %d", GST_TIME_ARGS (min), GST_TIME_ARGS (max), live);
+
+    /* for the combined latency we collect the MAX of all min latencies and
+     * the MIN of all max latencies */
+    if (min > fold->min)
+      fold->min = min;
+    if (fold->max == -1)
+      fold->max = max;
+    else if (max < fold->max)
+      fold->max = max;
+    if (fold->live == FALSE)
+      fold->live = live;
+  } else {
+    g_value_set_boolean (ret, FALSE);
+    GST_DEBUG_OBJECT (item, "failed query");
+  }
+
+  gst_object_unref (item);
+  return TRUE;
+}
+
+static void
+bin_query_latency_done (GstBin * bin, QueryFold * fold)
+{
+  /* store max in query result */
+  gst_query_set_latency (fold->query, fold->live, fold->min, fold->max);
+
+  GST_DEBUG_OBJECT (bin,
+      "latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
+      ", live %d", GST_TIME_ARGS (fold->min), GST_TIME_ARGS (fold->max),
+      fold->live);
+}
+
+/* generic fold, return first valid result */
+static gboolean
+bin_query_generic_fold (GstElement * item, GValue * ret, QueryFold * fold)
+{
+  gboolean res;
+
+  if ((res = gst_element_query (item, fold->query))) {
+    g_value_set_boolean (ret, TRUE);
+    GST_DEBUG_OBJECT (item, "answered query %p", fold->query);
+  }
+
+  gst_object_unref (item);
+
+  /* and stop as soon as we have a valid result */
+  return !res;
+}
+
+static gboolean
+gst_bin_query (GstElement * element, GstQuery * query)
+{
+  GstBin *bin = GST_BIN (element);
+  GstIterator *iter;
+  gboolean res = FALSE;
+  GstIteratorFoldFunction fold_func;
+  QueryInitFunction fold_init = NULL;
+  QueryDoneFunction fold_done = NULL;
+  QueryFold fold_data;
+  GValue ret = { 0 };
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_DURATION:
+    {
+#ifdef DURATION_CACHING
+      GList *cached;
+      GstFormat qformat;
+
+      gst_query_parse_duration (query, &qformat, NULL);
+
+      /* find cached duration query */
+      GST_OBJECT_LOCK (bin);
+      for (cached = bin->messages; cached; cached = g_list_next (cached)) {
+        GstMessage *message = (GstMessage *) cached->data;
+
+        if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_DURATION &&
+            GST_MESSAGE_SRC (message) == GST_OBJECT_CAST (bin)) {
+          GstFormat format;
+          gint64 duration;
+
+          gst_message_parse_duration (message, &format, &duration);
+
+          /* if cached same format, copy duration in query result */
+          if (format == qformat) {
+            GST_DEBUG_OBJECT (bin, "return cached duration %" G_GINT64_FORMAT,
+                duration);
+            GST_OBJECT_UNLOCK (bin);
+
+            gst_query_set_duration (query, qformat, duration);
+            res = TRUE;
+            goto exit;
+          }
+        }
+      }
+      GST_OBJECT_UNLOCK (bin);
+#endif
+      /* no cached value found, iterate and collect durations */
+      fold_func = (GstIteratorFoldFunction) bin_query_duration_fold;
+      fold_init = bin_query_min_max_init;
+      fold_done = bin_query_duration_done;
+      break;
+    }
+    case GST_QUERY_POSITION:
+    {
+      fold_func = (GstIteratorFoldFunction) bin_query_position_fold;
+      fold_init = bin_query_min_max_init;
+      fold_done = bin_query_position_done;
+      break;
+    }
+    case GST_QUERY_LATENCY:
+    {
+      fold_func = (GstIteratorFoldFunction) bin_query_latency_fold;
+      fold_init = bin_query_min_max_init;
+      fold_done = bin_query_latency_done;
+      res = TRUE;
+      break;
+    }
+    default:
+      fold_func = (GstIteratorFoldFunction) bin_query_generic_fold;
+      break;
+  }
+
+  fold_data.query = query;
+
+  g_value_init (&ret, G_TYPE_BOOLEAN);
+  g_value_set_boolean (&ret, res);
+
+  iter = gst_bin_iterate_sinks (bin);
+  GST_DEBUG_OBJECT (bin, "Sending query %p (type %s) to sink children",
+      query, GST_QUERY_TYPE_NAME (query));
+
+  if (fold_init)
+    fold_init (bin, &fold_data);
+
+  while (TRUE) {
+    GstIteratorResult ires;
+
+    ires = gst_iterator_fold (iter, fold_func, &ret, &fold_data);
+
+    switch (ires) {
+      case GST_ITERATOR_RESYNC:
+        gst_iterator_resync (iter);
+        if (fold_init)
+          fold_init (bin, &fold_data);
+        g_value_set_boolean (&ret, res);
+        break;
+      case GST_ITERATOR_OK:
+      case GST_ITERATOR_DONE:
+        res = g_value_get_boolean (&ret);
+        if (fold_done != NULL && res)
+          fold_done (bin, &fold_data);
+        goto done;
+      default:
+        res = FALSE;
+        goto done;
+    }
+  }
+done:
+  gst_iterator_free (iter);
+
+#ifdef DURATION_CACHING
+exit:
+#endif
+  GST_DEBUG_OBJECT (bin, "query %p result %d", query, res);
+
+  return res;
+}
+
+static gint
+compare_name (GstElement * element, const gchar * name)
+{
+  gint eq;
+
+  GST_OBJECT_LOCK (element);
+  eq = strcmp (GST_ELEMENT_NAME (element), name);
+  GST_OBJECT_UNLOCK (element);
+
+  if (eq != 0) {
+    gst_object_unref (element);
+  }
+  return eq;
+}
+
+/**
+ * gst_bin_get_by_name:
+ * @bin: a #GstBin
+ * @name: the element name to search for
+ *
+ * Gets the element with the given name from a bin. This
+ * function recurses into child bins.
+ *
+ * Returns NULL if no element with the given name is found in the bin.
+ *
+ * MT safe.  Caller owns returned reference.
+ *
+ * Returns: the #GstElement with the given name, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstElement *
+gst_bin_get_by_name (GstBin * bin, const gchar * name)
+{
+  GstIterator *children;
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+
+  GST_CAT_INFO (GST_CAT_PARENTAGE, "[%s]: looking up child element %s",
+      GST_ELEMENT_NAME (bin), name);
+
+  children = gst_bin_iterate_recurse (bin);
+  result = gst_iterator_find_custom (children,
+      (GCompareFunc) compare_name, (gpointer) name);
+  gst_iterator_free (children);
+
+  return GST_ELEMENT_CAST (result);
+}
+
+/**
+ * gst_bin_get_by_name_recurse_up:
+ * @bin: a #GstBin
+ * @name: the element name to search for
+ *
+ * Gets the element with the given name from this bin. If the
+ * element is not found, a recursion is performed on the parent bin.
+ *
+ * Returns NULL if:
+ * - no element with the given name is found in the bin
+ *
+ * MT safe.  Caller owns returned reference.
+ *
+ * Returns: the #GstElement with the given name, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstElement *
+gst_bin_get_by_name_recurse_up (GstBin * bin, const gchar * name)
+{
+  GstElement *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+  g_return_val_if_fail (name != NULL, NULL);
+
+  result = gst_bin_get_by_name (bin, name);
+
+  if (!result) {
+    GstObject *parent;
+
+    parent = gst_object_get_parent (GST_OBJECT_CAST (bin));
+    if (parent) {
+      if (GST_IS_BIN (parent)) {
+        result = gst_bin_get_by_name_recurse_up (GST_BIN_CAST (parent), name);
+      }
+      gst_object_unref (parent);
+    }
+  }
+
+  return result;
+}
+
+static gint
+compare_interface (GstElement * element, gpointer interface)
+{
+  GType interface_type = (GType) interface;
+  gint ret;
+
+  if (G_TYPE_CHECK_INSTANCE_TYPE (element, interface_type)) {
+    ret = 0;
+  } else {
+    /* we did not find the element, need to release the ref
+     * added by the iterator */
+    gst_object_unref (element);
+    ret = 1;
+  }
+  return ret;
+}
+
+/**
+ * gst_bin_get_by_interface:
+ * @bin: a #GstBin
+ * @iface: the #GType of an interface
+ *
+ * Looks for an element inside the bin that implements the given
+ * interface. If such an element is found, it returns the element.
+ * You can cast this element to the given interface afterwards.  If you want
+ * all elements that implement the interface, use
+ * gst_bin_iterate_all_by_interface(). This function recurses into child bins.
+ *
+ * MT safe.  Caller owns returned reference.
+ *
+ * Returns: A #GstElement inside the bin implementing the interface
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstElement *
+gst_bin_get_by_interface (GstBin * bin, GType iface)
+{
+  GstIterator *children;
+  gpointer result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+  g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
+
+  children = gst_bin_iterate_recurse (bin);
+  result = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
+      (gpointer) iface);
+  gst_iterator_free (children);
+
+  return GST_ELEMENT_CAST (result);
+}
+
+/**
+ * gst_bin_iterate_all_by_interface:
+ * @bin: a #GstBin
+ * @iface: the #GType of an interface
+ *
+ * Looks for all elements inside the bin that implements the given
+ * interface. You can safely cast all returned elements to the given interface.
+ * The function recurses inside child bins. The iterator will yield a series
+ * of #GstElement that should be unreffed after use.
+ *
+ * Each element yielded by the iterator will have its refcount increased, so
+ * unref after use.
+ *
+ * MT safe.  Caller owns returned value.
+ *
+ * Returns: a #GstIterator of #GstElement for all elements in the bin
+ *          implementing the given interface, or NULL
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstIterator *
+gst_bin_iterate_all_by_interface (GstBin * bin, GType iface)
+{
+  GstIterator *children;
+  GstIterator *result;
+
+  g_return_val_if_fail (GST_IS_BIN (bin), NULL);
+  g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
+
+  children = gst_bin_iterate_recurse (bin);
+  result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
+      (gpointer) iface);
+
+  return result;
+}
+
+#ifndef GST_DISABLE_LOADSAVE
+static xmlNodePtr
+gst_bin_save_thyself (GstObject * object, xmlNodePtr parent)
+{
+  GstBin *bin = GST_BIN (object);
+  xmlNodePtr childlist, elementnode;
+  GList *children;
+  GstElement *child;
+
+  if (GST_OBJECT_CLASS (parent_class)->save_thyself)
+    GST_OBJECT_CLASS (parent_class)->save_thyself (GST_OBJECT (bin), parent);
+
+  childlist = xmlNewChild (parent, NULL, (xmlChar *) "children", NULL);
+
+  GST_CAT_INFO (GST_CAT_XML, "[%s]: saving %d children",
+      GST_ELEMENT_NAME (bin), bin->numchildren);
+
+  children = bin->children;
+  while (children) {
+    child = GST_ELEMENT (children->data);
+    elementnode = xmlNewChild (childlist, NULL, (xmlChar *) "element", NULL);
+    gst_object_save_thyself (GST_OBJECT (child), elementnode);
+    children = g_list_next (children);
+  }
+  return childlist;
+}
+
+static void
+gst_bin_restore_thyself (GstObject * object, xmlNodePtr self)
+{
+  GstBin *bin = GST_BIN (object);
+  xmlNodePtr field = self->xmlChildrenNode;
+  xmlNodePtr childlist;
+
+  while (field) {
+    if (!strcmp ((char *) field->name, "children")) {
+      GST_CAT_INFO (GST_CAT_XML, "[%s]: loading children",
+          GST_ELEMENT_NAME (object));
+      childlist = field->xmlChildrenNode;
+      while (childlist) {
+        if (!strcmp ((char *) childlist->name, "element")) {
+          /* gst_xml_make_element will gst_bin_add() the element to ourself */
+          gst_xml_make_element (childlist, GST_OBJECT (bin));
+        }
+        childlist = childlist->next;
+      }
+    }
+
+    field = field->next;
+  }
+  if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
+    (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
+}
+#endif /* GST_DISABLE_LOADSAVE */