aggregator: Add new GstAggregator base class

This base class has been added to a newly created libgstbadbase library

Co-Authored by: Mathieu Duponchelle <mathieu.duponchelle@opencreed.com>

https://bugzilla.gnome.org/show_bug.cgi?id=731917

11 files changed, 2704 insertions, 2 deletions

diff --git a/configure.ac b/configure.ac
index b0fdd3181..a28b9bd32 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3221,6 +3221,7 @@ gst-libs/gst/codecparsers/Makefile
 gst-libs/gst/mpegts/Makefile
 gst-libs/gst/uridownloader/Makefile
 gst-libs/gst/wayland/Makefile
+gst-libs/gst/base/Makefile
 sys/Makefile
 sys/dshowdecwrapper/Makefile
 sys/acmenc/Makefile
@@ -3359,6 +3360,8 @@ pkgconfig/gstreamer-mpegts.pc
 pkgconfig/gstreamer-mpegts-uninstalled.pc
 pkgconfig/gstreamer-wayland.pc
 pkgconfig/gstreamer-wayland-uninstalled.pc
+pkgconfig/gstreamer-bad-base.pc
+pkgconfig/gstreamer-bad-base-uninstalled.pc
 tools/Makefile
 m4/Makefile
 )
diff --git a/docs/libs/gst-plugins-bad-libs-docs.sgml b/docs/libs/gst-plugins-bad-libs-docs.sgml
index 44c2cd66c..7ef65da68 100644
--- a/docs/libs/gst-plugins-bad-libs-docs.sgml
+++ b/docs/libs/gst-plugins-bad-libs-docs.sgml
@@ -57,6 +57,12 @@
       <xi:include href="xml/gstinsertbin.xml" />
     </chapter>
 
+    <chapter id="base">
+      <title>GStreamer Base classes from gst-plugins-bad</title>
+      <xi:include href="xml/gstaggregator.xml" />
+      <xi:include href="xml/gstaggregatorpad.xml" />
+    </chapter>
+
     <chapter id="gl">
       <title>OpenGL Helper Library</title>
       <xi:include href="xml/gstglapi.xml"/>
diff --git a/docs/libs/gst-plugins-bad-libs-sections.txt b/docs/libs/gst-plugins-bad-libs-sections.txt
index c54978eee..de8168687 100644
--- a/docs/libs/gst-plugins-bad-libs-sections.txt
+++ b/docs/libs/gst-plugins-bad-libs-sections.txt
@@ -1290,3 +1290,38 @@ gst_gl_window_x11_get_type
 GstGLWindowX11Private
 x11_event_source_new
 </SECTION>
+
+<SECTION>
+<FILE>gstaggregator</FILE>
+<TITLE>GstAggregator</TITLE>
+GstAggregator
+GstAggregatorClass
+gst_aggregator_finish_buffer
+gst_aggregator_set_src_caps
+gst_aggregator_iterate_sinkpads
+<SUBSECTION Standard>
+GST_IS_AGGREGATOR
+GST_IS_AGGREGATOR_CLASS
+GST_TYPE_AGGREGATOR
+GST_AGGREGATOR
+GST_AGGREGATOR_CLASS
+GST_AGGREGATOR_GET_CLASS
+gst_aggregator_get_type
+</SECTION>
+
+<SECTION>
+<FILE>gstaggregatorpad</FILE>
+<TITLE>GstAggregatorPad</TITLE>
+GstAggregatorPad
+GstAggregatorPadClass
+gst_aggregator_pad_steal_buffer
+gst_aggregator_pad_get_buffer
+<SUBSECTION Standard>
+GST_IS_AGGREGATOR_PAD
+GST_IS_AGGREGATOR_PAD_CLASS
+GST_TYPE_AGGREGATOR_PAD
+GST_AGGREGATOR_PAD
+GST_AGGREGATOR_PAD_CLASS
+GST_AGGREGATOR_PAD_GET_CLASS
+gst_aggregator_pad_get_type
+</SECTION>
diff --git a/gst-libs/gst/Makefile.am b/gst-libs/gst/Makefile.am
index 93abc17bf..7932f418f 100644
--- a/gst-libs/gst/Makefile.am
+++ b/gst-libs/gst/Makefile.am
@@ -11,8 +11,8 @@ WAYLAND_DIR=wayland
 endif
 
 SUBDIRS = interfaces basecamerabinsrc codecparsers \
-	 insertbin uridownloader mpegts $(GL_DIR) $(WAYLAND_DIR)
+	 insertbin uridownloader mpegts base $(GL_DIR) $(WAYLAND_DIR)
 
 noinst_HEADERS = gst-i18n-plugin.h gettext.h glib-compat-private.h
 DIST_SUBDIRS = interfaces gl basecamerabinsrc codecparsers \
-	insertbin uridownloader mpegts wayland
+	insertbin uridownloader mpegts wayland base
diff --git a/gst-libs/gst/base/Makefile.am b/gst-libs/gst/base/Makefile.am
new file mode 100644
index 000000000..c71197b47
--- /dev/null
+++ b/gst-libs/gst/base/Makefile.am
@@ -0,0 +1,21 @@
+lib_LTLIBRARIES = libgstbadbase-@GST_API_VERSION@.la
+
+libgstbadbase_@GST_API_VERSION@_la_SOURCES = \
+	gstaggregator.c
+
+libgstbadbase_@GST_API_VERSION@_la_CFLAGS = $(GST_CFLAGS)
+libgstbadbase_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS)
+libgstbadbase_@GST_API_VERSION@_la_LDFLAGS = $(GST_LDFLAGS)
+
+libgstbadbase_@GST_API_VERSION@includedir = $(includedir)/gstreamer-@GST_API_VERSION@/gst/badbase/
+libgstbadbase_@GST_API_VERSION@include_HEADERS =	\
+	gstaggregator.h
+
+EXTRA_DIST = 
+
+CLEANFILES = *.gcno *.gcda *.gcov
+
+%.c.gcov: .libs/libgstbadbase_@GST_API_VERSION@_la-%.gcda %.c
+	$(GCOV) -b -f -o $^ > $@.out
+
+gcov: $(libgstbadbase_@GST_API_VERSION@_la_SOURCES:=.gcov)
diff --git a/gst-libs/gst/base/gstaggregator.c b/gst-libs/gst/base/gstaggregator.c
new file mode 100644
index 000000000..c5663840a
--- /dev/null
+++ b/gst-libs/gst/base/gstaggregator.c
@@ -0,0 +1,1323 @@
+/* GStreamer
+ * Copyright (C) 2014 Mathieu Duponchelle <mathieu.duponchelle@opencreed.com>
+ * Copyright (C) 2014 Thibault Saunier <tsaunier@gnome.org>
+ *
+ * gstaggregator.c:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+/**
+ * SECTION: gstaggregator
+ * @short_description: manages a set of pads with the purpose of
+ * aggregating their buffers.
+ * @see_also: gstcollectpads for historical reasons.
+ *
+ * Manages a set of pads with the purpose of aggregating their buffers.
+ * Control is given to the subclass when all pads have data.
+ * <itemizedlist>
+ *  <listitem><para>
+ *    Base class for mixers and muxers. Implementers should at least implement
+ *    the aggregate () vmethod.
+ *  </para></listitem>
+ *  <listitem><para>
+ *    When data is queued on all pads, tha aggregate vmethod is called.
+ *  </para></listitem>
+ *  <listitem><para>
+ *    One can peek at the data on any given GstAggregatorPad with the
+ *    gst_aggregator_pad_get_buffer () method, and take ownership of it
+ *    with the gst_aggregator_pad_steal_buffer () method. When a buffer
+ *    has been taken with steal_buffer (), a new buffer can be queued
+ *    on that pad.
+ *  </para></listitem>
+ *  <listitem><para>
+ *    If the subclass wishes to push a buffer downstream in its aggregate
+ *    implementation, it should do so through the
+ *    gst_aggregator_finish_buffer () method. This method will take care
+ *    of sending and ordering mandatory events such as stream start, caps
+ *    and segment.
+ *  </para></listitem>
+ *  <listitem><para>
+ *    Same goes for EOS events, which should not be pushed directly by the
+ *    subclass, it should instead return GST_FLOW_EOS in its aggregate
+ *    implementation.
+ *  </para></listitem>
+ * </itemizedlist>
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <string.h>             /* strlen */
+
+#include "gstaggregator.h"
+
+
+/*  Might become API */
+static void gst_aggregator_merge_tags (GstAggregator * aggregator,
+    const GstTagList * tags, GstTagMergeMode mode);
+
+GST_DEBUG_CATEGORY_STATIC (aggregator_debug);
+#define GST_CAT_DEFAULT aggregator_debug
+
+/* GstAggregatorPad definitions */
+#define PAD_LOCK_EVENT(pad)   G_STMT_START {                            \
+  GST_LOG_OBJECT (pad, "Taking EVENT lock from thread %p",              \
+        g_thread_self());                                               \
+  g_mutex_lock(&pad->priv->event_lock);                                 \
+  GST_LOG_OBJECT (pad, "Took EVENT lock from thread %p",              \
+        g_thread_self());                                               \
+  } G_STMT_END
+
+#define PAD_UNLOCK_EVENT(pad)  G_STMT_START {                           \
+  GST_LOG_OBJECT (pad, "Releasing EVENT lock from thread %p",          \
+        g_thread_self());                                               \
+  g_mutex_unlock(&pad->priv->event_lock);                               \
+  GST_LOG_OBJECT (pad, "Release EVENT lock from thread %p",          \
+        g_thread_self());                                               \
+  } G_STMT_END
+
+
+#define PAD_WAIT_EVENT(pad)   G_STMT_START {                            \
+  GST_LOG_OBJECT (pad, "Waiting for EVENT on thread %p",               \
+        g_thread_self());                                               \
+  g_cond_wait(&(((GstAggregatorPad* )pad)->priv->event_cond),       \
+      &(pad->priv->event_lock));                                        \
+  GST_LOG_OBJECT (pad, "DONE Waiting for EVENT on thread %p",               \
+        g_thread_self());                                               \
+  } G_STMT_END
+
+#define PAD_BROADCAST_EVENT(pad) {                                          \
+  GST_LOG_OBJECT (pad, "Signaling EVENT from thread %p",               \
+        g_thread_self());                                                   \
+  g_cond_broadcast(&(((GstAggregatorPad* )pad)->priv->event_cond)); \
+  }
+
+struct _GstAggregatorPadPrivate
+{
+  gboolean pending_flush_start;
+  gboolean pending_flush_stop;
+  gboolean pending_eos;
+  gboolean flushing;
+
+  GMutex event_lock;
+  GCond event_cond;
+};
+
+static gboolean
+_aggpad_flush (GstAggregatorPad * aggpad, GstAggregator * agg)
+{
+  GstAggregatorPadClass *klass = GST_AGGREGATOR_PAD_GET_CLASS (aggpad);
+
+  aggpad->eos = FALSE;
+  aggpad->priv->flushing = FALSE;
+
+  if (klass->flush)
+    return klass->flush (aggpad, agg);
+
+  return TRUE;
+}
+
+/*************************************
+ * GstAggregator implementation  *
+ *************************************/
+static GstElementClass *aggregator_parent_class = NULL;
+
+#define MAIN_CONTEXT_LOCK(self) G_STMT_START {                       \
+  GST_LOG_OBJECT (self, "Getting MAIN_CONTEXT_LOCK in thread %p",    \
+        g_thread_self());                                            \
+  g_mutex_lock(&((GstAggregator*)self)->priv->mcontext_lock);    \
+  GST_LOG_OBJECT (self, "Got MAIN_CONTEXT_LOCK in thread %p",        \
+        g_thread_self());                                            \
+} G_STMT_END
+
+#define MAIN_CONTEXT_UNLOCK(self) G_STMT_START {                     \
+  g_mutex_unlock(&((GstAggregator*)self)->priv->mcontext_lock);  \
+  GST_LOG_OBJECT (self, "Unlocked MAIN_CONTEXT_LOCK in thread %p",   \
+        g_thread_self());                                            \
+} G_STMT_END
+
+struct _GstAggregatorPrivate
+{
+  gint padcount;
+
+  GMainContext *mcontext;
+
+  /* Our state is >= PAUSED */
+  gboolean running;
+
+  /* Ensure that when we remove all sources from the maincontext
+   * we can not add any source, avoiding:
+   * "g_source_attach: assertion '!SOURCE_DESTROYED (source)' failed" */
+  GMutex mcontext_lock;
+
+  gboolean send_stream_start;
+  gboolean send_segment;
+  gboolean flush_seeking;
+  gboolean pending_flush_start;
+  gboolean send_eos;
+  GstFlowReturn flow_return;
+
+  GstCaps *srccaps;
+
+  GstTagList *tags;
+  gboolean tags_changed;
+};
+
+typedef struct
+{
+  GstEvent *event;
+  gboolean result;
+  gboolean flush;
+} EventData;
+
+/**
+ * gst_aggregator_iterate_sinkpads:
+ * @self: The #GstAggregator
+ * @func: The function to call.
+ * @user_data: The data to pass to @func.
+ *
+ * Iterate the sinkpads of aggregator to call a function on them.
+ *
+ * This method guarantees that @func will be called only once for each
+ * sink pad.
+ */
+gboolean
+gst_aggregator_iterate_sinkpads (GstAggregator * self,
+    GstAggregatorPadForeachFunc func, gpointer user_data)
+{
+  gboolean result = FALSE;
+  GstIterator *iter;
+  gboolean done = FALSE;
+  GValue item = { 0, };
+  GList *seen_pads = NULL;
+
+  iter = gst_element_iterate_sink_pads (GST_ELEMENT (self));
+
+  if (!iter)
+    goto no_iter;
+
+  while (!done) {
+    switch (gst_iterator_next (iter, &item)) {
+      case GST_ITERATOR_OK:
+      {
+        GstPad *pad;
+
+        pad = g_value_get_object (&item);
+
+        /* if already pushed, skip. FIXME, find something faster to tag pads */
+        if (pad == NULL || g_list_find (seen_pads, pad)) {
+          g_value_reset (&item);
+          break;
+        }
+
+        GST_LOG_OBJECT (self, "calling function on pad %s:%s",
+            GST_DEBUG_PAD_NAME (pad));
+        result = func (self, pad, user_data);
+
+        done = !result;
+
+        seen_pads = g_list_prepend (seen_pads, pad);
+
+        g_value_reset (&item);
+        break;
+      }
+      case GST_ITERATOR_RESYNC:
+        gst_iterator_resync (iter);
+        break;
+      case GST_ITERATOR_ERROR:
+        GST_ERROR_OBJECT (self,
+            "Could not iterate over internally linked pads");
+        done = TRUE;
+        break;
+      case GST_ITERATOR_DONE:
+        done = TRUE;
+        break;
+    }
+  }
+  g_value_unset (&item);
+  gst_iterator_free (iter);
+
+  if (seen_pads == NULL) {
+    GST_DEBUG_OBJECT (self, "No pad seen");
+    return FALSE;
+  }
+
+  g_list_free (seen_pads);
+
+no_iter:
+  return result;
+}
+
+static inline gboolean
+_check_all_pads_with_data_or_eos (GstAggregator * self,
+    GstAggregatorPad * aggpad)
+{
+  if (aggpad->buffer || aggpad->eos) {
+    return TRUE;
+  }
+
+  GST_LOG_OBJECT (aggpad, "Not ready to be aggregated");
+
+  return FALSE;
+}
+
+/**
+ * gst_aggregator_set_src_caps:
+ * @self: The #GstAggregator
+ * @caps: The #GstCaps to set later on the src pad.
+ *
+ * Sets the caps to be used on the src pad.
+ */
+void
+gst_aggregator_set_src_caps (GstAggregator * self, GstCaps * caps)
+{
+  gst_caps_replace (&self->priv->srccaps, caps);
+}
+
+static void
+_reset_flow_values (GstAggregator * self)
+{
+  self->priv->send_stream_start = TRUE;
+  self->priv->send_segment = TRUE;
+  gst_segment_init (&self->segment, GST_FORMAT_TIME);
+}
+
+static inline void
+_push_mandatory_events (GstAggregator * self)
+{
+  GstAggregatorPrivate *priv = self->priv;
+
+  if (g_atomic_int_get (&self->priv->send_stream_start)) {
+    gchar s_id[32];
+
+    GST_INFO_OBJECT (self, "pushing stream start");
+    /* stream-start (FIXME: create id based on input ids) */
+    g_snprintf (s_id, sizeof (s_id), "agg-%08x", g_random_int ());
+    if (!gst_pad_push_event (self->srcpad, gst_event_new_stream_start (s_id))) {
+      GST_WARNING_OBJECT (self->srcpad, "Sending stream start event failed");
+    }
+    g_atomic_int_set (&self->priv->send_stream_start, FALSE);
+  }
+
+  if (self->priv->srccaps) {
+
+    GST_INFO_OBJECT (self, "pushing caps: %" GST_PTR_FORMAT,
+        self->priv->srccaps);
+    if (!gst_pad_push_event (self->srcpad,
+            gst_event_new_caps (self->priv->srccaps))) {
+      GST_WARNING_OBJECT (self->srcpad, "Sending caps event failed");
+    }
+    self->priv->srccaps = NULL;
+  }
+
+  if (g_atomic_int_get (&self->priv->send_segment)) {
+    if (!g_atomic_int_get (&self->priv->flush_seeking)) {
+      GST_INFO_OBJECT (self, "pushing segment");
+      gst_pad_push_event (self->srcpad, gst_event_new_segment (&self->segment));
+      g_atomic_int_set (&self->priv->send_segment, FALSE);
+    }
+  }
+
+  if (priv->tags && priv->tags_changed) {
+    gst_pad_push_event (self->srcpad,
+        gst_event_new_tag (gst_tag_list_ref (priv->tags)));
+    priv->tags_changed = FALSE;
+  }
+}
+
+/**
+ * gst_aggregator_finish_buffer:
+ * @self: The #GstAggregator
+ * @buffer: the #GstBuffer to push.
+ *
+ * This method will take care of sending mandatory events before pushing
+ * the provided buffer.
+ */
+GstFlowReturn
+gst_aggregator_finish_buffer (GstAggregator * self, GstBuffer * buffer)
+{
+  _push_mandatory_events (self);
+
+  if (!g_atomic_int_get (&self->priv->flush_seeking) &&
+      gst_pad_is_active (self->srcpad)) {
+    GST_TRACE_OBJECT (self, "pushing buffer %" GST_PTR_FORMAT, buffer);
+    return gst_pad_push (self->srcpad, buffer);
+  } else {
+    GST_INFO_OBJECT (self, "Not pushing (active: %i, flushing: %i)",
+        g_atomic_int_get (&self->priv->flush_seeking),
+        gst_pad_is_active (self->srcpad));
+    return GST_FLOW_OK;
+  }
+}
+
+static void
+_push_eos (GstAggregator * self)
+{
+  _push_mandatory_events (self);
+
+  self->priv->send_eos = FALSE;
+  gst_pad_push_event (self->srcpad, gst_event_new_eos ());
+}
+
+static void
+_remove_all_sources (GstAggregator * self)
+{
+  GSource *source;
+
+  MAIN_CONTEXT_LOCK (self);
+  while ((source =
+          g_main_context_find_source_by_user_data (self->priv->mcontext,
+              self))) {
+    g_source_destroy (source);
+  }
+  MAIN_CONTEXT_UNLOCK (self);
+}
+
+static gboolean
+aggregate_func (GstAggregator * self)
+{
+  GstAggregatorPrivate *priv = self->priv;
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (self);
+
+  GST_LOG_OBJECT (self, "Checking aggregate");
+  while (priv->send_eos && gst_aggregator_iterate_sinkpads (self,
+          (GstAggregatorPadForeachFunc) _check_all_pads_with_data_or_eos,
+          NULL) && priv->running) {
+    GST_TRACE_OBJECT (self, "Actually aggregating!");
+
+    priv->flow_return = klass->aggregate (self);
+
+    if (priv->flow_return == GST_FLOW_EOS) {
+      g_main_context_wakeup (self->priv->mcontext);
+      _remove_all_sources (self);
+      _push_eos (self);
+    }
+
+    if (priv->flow_return == GST_FLOW_FLUSHING &&
+        g_atomic_int_get (&priv->flush_seeking))
+      priv->flow_return = GST_FLOW_OK;
+
+    GST_LOG_OBJECT (self, "flow return is %s",
+        gst_flow_get_name (priv->flow_return));
+
+    if (priv->flow_return != GST_FLOW_OK)
+      break;
+  }
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+iterate_main_context_func (GstAggregator * self)
+{
+  if (self->priv->running == FALSE) {
+    GST_DEBUG_OBJECT (self, "Not running anymore");
+
+    return;
+  }
+
+  g_main_context_iteration (self->priv->mcontext, TRUE);
+}
+
+static gboolean
+_start (GstAggregator * self)
+{
+  self->priv->running = TRUE;
+  self->priv->send_stream_start = TRUE;
+  self->priv->send_segment = TRUE;
+  self->priv->send_eos = TRUE;
+  self->priv->srccaps = NULL;
+
+  return TRUE;
+}
+
+static gboolean
+_check_pending_flush_stop (GstAggregatorPad * pad)
+{
+  return (!pad->priv->pending_flush_stop && !pad->priv->pending_flush_start);
+}
+
+static gboolean
+_stop_srcpad_task (GstAggregator * self, GstEvent * flush_start)
+{
+  gboolean res = TRUE;
+
+  GST_INFO_OBJECT (self, "%s srcpad task",
+      flush_start ? "Pausing" : "Stopping");
+
+  self->priv->running = FALSE;
+
+  /*  Clean the stack of GSource set on the MainContext */
+  g_main_context_wakeup (self->priv->mcontext);
+  _remove_all_sources (self);
+  if (flush_start) {
+    res = gst_pad_push_event (self->srcpad, flush_start);
+  }
+
+  gst_pad_stop_task (self->srcpad);
+
+  return res;
+}
+
+static void
+_start_srcpad_task (GstAggregator * self)
+{
+  GST_INFO_OBJECT (self, "Starting srcpad task");
+
+  self->priv->running = TRUE;
+  gst_pad_start_task (GST_PAD (self->srcpad),
+      (GstTaskFunction) iterate_main_context_func, self, NULL);
+}
+
+static inline void
+_add_aggregate_gsource (GstAggregator * self)
+{
+  MAIN_CONTEXT_LOCK (self);
+  g_main_context_invoke (self->priv->mcontext, (GSourceFunc) aggregate_func,
+      self);
+  MAIN_CONTEXT_UNLOCK (self);
+}
+
+static GstFlowReturn
+_flush (GstAggregator * self)
+{
+  GstFlowReturn ret = GST_FLOW_OK;
+  GstAggregatorPrivate *priv = self->priv;
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (self);
+
+  GST_DEBUG_OBJECT (self, "Flushing everything");
+  g_atomic_int_set (&priv->send_segment, TRUE);
+  g_atomic_int_set (&priv->flush_seeking, FALSE);
+  g_atomic_int_set (&priv->tags_changed, FALSE);
+  if (klass->flush)
+    ret = klass->flush (self);
+
+  return ret;
+}
+
+static gboolean
+_all_flush_stop_received (GstAggregator * self)
+{
+  GList *tmp;
+  GstAggregatorPad *tmppad;
+
+  GST_OBJECT_LOCK (self);
+  for (tmp = GST_ELEMENT (self)->sinkpads; tmp; tmp = tmp->next) {
+    tmppad = (GstAggregatorPad *) tmp->data;
+
+    if (_check_pending_flush_stop (tmppad) == FALSE) {
+      GST_DEBUG_OBJECT (tmppad, "Is not last %i -- %i",
+          tmppad->priv->pending_flush_start, tmppad->priv->pending_flush_stop);
+      GST_OBJECT_UNLOCK (self);
+      return FALSE;
+    }
+  }
+  GST_OBJECT_UNLOCK (self);
+
+  return TRUE;
+}
+
+/* GstAggregator vmethods default implementations */
+static gboolean
+_sink_event (GstAggregator * self, GstAggregatorPad * aggpad, GstEvent * event)
+{
+  gboolean res = TRUE;
+  GstPad *pad = GST_PAD (aggpad);
+  GstAggregatorPrivate *priv = self->priv;
+  GstAggregatorPadPrivate *padpriv = aggpad->priv;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_FLUSH_START:
+    {
+      GstBuffer *tmpbuf;
+
+      g_atomic_int_set (&aggpad->priv->flushing, TRUE);
+      /*  Remove pad buffer and wake up the streaming thread */
+      tmpbuf = gst_aggregator_pad_steal_buffer (aggpad);
+      gst_buffer_replace (&tmpbuf, NULL);
+      if (g_atomic_int_compare_and_exchange (&padpriv->pending_flush_start,
+              TRUE, FALSE) == TRUE) {
+        GST_DEBUG_OBJECT (aggpad, "Expecting FLUSH_STOP now");
+        g_atomic_int_set (&padpriv->pending_flush_stop, TRUE);
+      }
+
+      if (g_atomic_int_get (&priv->flush_seeking)) {
+        /* If flush_seeking we forward the first FLUSH_START */
+        if (g_atomic_int_compare_and_exchange (&priv->pending_flush_start,
+                TRUE, FALSE) == TRUE) {
+
+          GST_DEBUG_OBJECT (self, "Flushing, pausing srcpad task");
+          priv->flow_return = GST_FLOW_OK;
+          _stop_srcpad_task (self, event);
+
+          GST_INFO_OBJECT (self, "Getting STREAM_LOCK while seeking");
+          GST_PAD_STREAM_LOCK (self->srcpad);
+          GST_LOG_OBJECT (self, "GOT STREAM_LOCK");
+          event = NULL;
+          goto eat;
+        }
+      }
+
+      /* We forward only in one case: right after flush_seeking */
+      goto eat;
+    }
+    case GST_EVENT_FLUSH_STOP:
+    {
+      GST_DEBUG_OBJECT (aggpad, "Got FLUSH_STOP");
+
+      _aggpad_flush (aggpad, self);
+      if (g_atomic_int_get (&priv->flush_seeking)) {
+        g_atomic_int_set (&aggpad->priv->pending_flush_stop, FALSE);
+
+        if (g_atomic_int_get (&priv->flush_seeking)) {
+          if (_all_flush_stop_received (self)) {
+            /* That means we received FLUSH_STOP/FLUSH_STOP on
+             * all sinkpads -- Seeking is Done... sending FLUSH_STOP */
+            _flush (self);
+            gst_pad_push_event (self->srcpad, event);
+            priv->send_eos = TRUE;
+            event = NULL;
+            _add_aggregate_gsource (self);
+
+            GST_INFO_OBJECT (self, "Releasing source pad STREAM_LOCK");
+            GST_PAD_STREAM_UNLOCK (self->srcpad);
+            _start_srcpad_task (self);
+          }
+        }
+      }
+
+      /* We never forward the event */
+      goto eat;
+    }
+    case GST_EVENT_EOS:
+    {
+      GST_DEBUG_OBJECT (aggpad, "EOS");
+
+      /* We still have a buffer, and we don't want the subclass to have to
+       * check for it. Mark pending_eos, eos will be set when steal_buffer is
+       * called
+       */
+      PAD_LOCK_EVENT (aggpad);
+      if (!aggpad->buffer) {
+        aggpad->eos = TRUE;
+      } else {
+        aggpad->priv->pending_eos = TRUE;
+      }
+      PAD_UNLOCK_EVENT (aggpad);
+
+      _add_aggregate_gsource (self);
+      goto eat;
+    }
+    case GST_EVENT_SEGMENT:
+    {
+      gst_event_copy_segment (event, &aggpad->segment);
+      PAD_UNLOCK_EVENT (aggpad);
+
+      goto eat;
+    }
+    case GST_EVENT_STREAM_START:
+    {
+      goto eat;
+    }
+    case GST_EVENT_TAG:
+    {
+      GstTagList *tags;
+
+      gst_event_parse_tag (event, &tags);
+
+      if (gst_tag_list_get_scope (tags) == GST_TAG_SCOPE_STREAM) {
+        gst_aggregator_merge_tags (self, tags, GST_TAG_MERGE_REPLACE);
+        gst_event_unref (event);
+        event = NULL;
+        goto eat;
+      }
+      break;
+    }
+    default:
+    {
+      break;
+    }
+  }
+
+  GST_DEBUG_OBJECT (pad, "Forwarding event: %" GST_PTR_FORMAT, event);
+  return gst_pad_event_default (pad, GST_OBJECT (self), event);
+
+eat:
+  GST_DEBUG_OBJECT (pad, "Eating event: %" GST_PTR_FORMAT, event);
+  if (event)
+    gst_event_unref (event);
+
+  return res;
+}
+
+static gboolean
+_stop (GstAggregator * agg)
+{
+  _reset_flow_values (agg);
+
+  return TRUE;
+}
+
+/* GstElement vmethods implementations */
+static GstStateChangeReturn
+_change_state (GstElement * element, GstStateChange transition)
+{
+  GstStateChangeReturn ret;
+  GstAggregator *self = GST_AGGREGATOR (element);
+  GstAggregatorClass *agg_class = GST_AGGREGATOR_GET_CLASS (self);
+
+
+  switch (transition) {
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      agg_class->start (self);
+      break;
+    default:
+      break;
+  }
+
+  if ((ret =
+          GST_ELEMENT_CLASS (aggregator_parent_class)->change_state (element,
+              transition)) == GST_STATE_CHANGE_FAILURE)
+    goto failure;
+
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      agg_class->stop (self);
+      break;
+    default:
+      break;
+  }
+
+  return ret;
+
+failure:
+  {
+    GST_ERROR_OBJECT (element, "parent failed state change");
+    return ret;
+  }
+}
+
+static void
+_release_pad (GstElement * element, GstPad * pad)
+{
+  GstBuffer *tmpbuf;
+
+  GstAggregator *self = GST_AGGREGATOR (element);
+  GstAggregatorPad *aggpad = GST_AGGREGATOR_PAD (pad);
+
+  GST_INFO_OBJECT (pad, "Removing pad");
+
+  g_atomic_int_set (&aggpad->priv->flushing, TRUE);
+  tmpbuf = gst_aggregator_pad_steal_buffer (aggpad);
+  gst_buffer_replace (&tmpbuf, NULL);
+  gst_element_remove_pad (element, pad);
+
+  /* Something changed make sure we try to aggregate */
+  _add_aggregate_gsource (self);
+}
+
+static GstPad *
+_request_new_pad (GstElement * element,
+    GstPadTemplate * templ, const gchar * req_name, const GstCaps * caps)
+{
+  GstAggregator *self;
+  GstAggregatorPad *agg_pad;
+
+  GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
+  GstAggregatorPrivate *priv = GST_AGGREGATOR (element)->priv;
+
+  self = GST_AGGREGATOR (element);
+
+  if (templ == gst_element_class_get_pad_template (klass, "sink_%u")) {
+    guint serial = 0;
+    gchar *name = NULL;
+
+    GST_OBJECT_LOCK (element);
+    if (req_name == NULL || strlen (req_name) < 6
+        || !g_str_has_prefix (req_name, "sink_")) {
+      /* no name given when requesting the pad, use next available int */
+      priv->padcount++;
+    } else {
+      /* parse serial number from requested padname */
+      serial = g_ascii_strtoull (&req_name[5], NULL, 10);
+      if (serial >= priv->padcount)
+        priv->padcount = serial + 1;
+    }
+
+    name = g_strdup_printf ("sink_%u", priv->padcount);
+    agg_pad = g_object_new (GST_AGGREGATOR_GET_CLASS (self)->sinkpads_type,
+        "name", name, "direction", GST_PAD_SINK, "template", templ, NULL);
+    g_free (name);
+    GST_OBJECT_UNLOCK (element);
+
+  } else {
+    return NULL;
+  }
+
+  GST_DEBUG_OBJECT (element, "Adding pad %s", GST_PAD_NAME (agg_pad));
+
+  if (priv->running)
+    gst_pad_set_active (GST_PAD (agg_pad), TRUE);
+
+  /* add the pad to the element */
+  gst_element_add_pad (element, GST_PAD (agg_pad));
+
+  return GST_PAD (agg_pad);
+}
+
+static gboolean
+_src_query (GstAggregator * self, GstQuery * query)
+{
+  gboolean res = TRUE;
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_SEEKING:
+    {
+      GstFormat format;
+
+      /* don't pass it along as some (file)sink might claim it does
+       * whereas with a collectpads in between that will not likely work */
+      gst_query_parse_seeking (query, &format, NULL, NULL, NULL);
+      gst_query_set_seeking (query, format, FALSE, 0, -1);
+      res = TRUE;
+
+      goto discard;
+    }
+    default:
+      break;
+  }
+
+  return gst_pad_query_default (self->srcpad, GST_OBJECT (self), query);
+
+discard:
+  return res;
+}
+
+static gboolean
+event_forward_func (GstPad * pad, EventData * evdata)
+{
+  gboolean ret = TRUE;
+  GstPad *peer = gst_pad_get_peer (pad);
+  GstAggregatorPadPrivate *padpriv = GST_AGGREGATOR_PAD (pad)->priv;
+
+  if (peer) {
+    ret = gst_pad_send_event (peer, gst_event_ref (evdata->event));
+    GST_DEBUG_OBJECT (pad, "return of event push is %d", ret);
+    gst_object_unref (peer);
+  }
+
+  evdata->result &= ret;
+
+  if (ret == FALSE) {
+    if (GST_EVENT_TYPE (evdata->event) == GST_EVENT_SEEK)
+      GST_ERROR_OBJECT (pad, "Event %" GST_PTR_FORMAT " failed", evdata->event);
+    else
+      GST_INFO_OBJECT (pad, "Event %" GST_PTR_FORMAT " failed", evdata->event);
+
+    if (evdata->flush) {
+      padpriv->pending_flush_start = FALSE;
+      padpriv->pending_flush_stop = FALSE;
+    }
+  }
+
+  /* Always send to all pads */
+  return FALSE;
+}
+
+static gboolean
+_set_flush_pending (GstAggregator * self, GstAggregatorPad * pad,
+    gpointer udata)
+{
+  pad->priv->pending_flush_start = TRUE;
+  pad->priv->pending_flush_stop = FALSE;
+
+  return TRUE;
+}
+
+static gboolean
+_forward_event_to_all_sinkpads (GstAggregator * self, GstEvent * event,
+    gboolean flush)
+{
+  EventData evdata;
+
+  evdata.event = event;
+  evdata.result = TRUE;
+  evdata.flush = flush;
+
+  /* We first need to set all pads as flushing in a first pass
+   * as flush_start flush_stop is sometimes sent synchronously
+   * while we send the seek event */
+  if (flush)
+    gst_aggregator_iterate_sinkpads (self,
+        (GstAggregatorPadForeachFunc) _set_flush_pending, NULL);
+  gst_pad_forward (self->srcpad, (GstPadForwardFunction) event_forward_func,
+      &evdata);
+
+  gst_event_unref (event);
+
+  return evdata.result;
+}
+
+static gboolean
+_do_seek (GstAggregator * self, GstEvent * event)
+{
+  gdouble rate;
+  GstFormat fmt;
+  GstSeekFlags flags;
+  GstSeekType start_type, stop_type;
+  gint64 start, stop;
+  gboolean flush;
+  gboolean res;
+  GstAggregatorPrivate *priv = self->priv;
+
+  gst_event_parse_seek (event, &rate, &fmt, &flags, &start_type,
+      &start, &stop_type, &stop);
+
+  GST_INFO_OBJECT (self, "starting SEEK");
+
+  flush = flags & GST_SEEK_FLAG_FLUSH;
+
+  if (flush) {
+    g_atomic_int_set (&priv->pending_flush_start, TRUE);
+    g_atomic_int_set (&priv->flush_seeking, TRUE);
+  }
+
+  gst_segment_do_seek (&self->segment, rate, fmt, flags, start_type, start,
+      stop_type, stop, NULL);
+
+  /* forward the seek upstream */
+  res = _forward_event_to_all_sinkpads (self, event, flush);
+  event = NULL;
+
+  if (!res) {
+    g_atomic_int_set (&priv->flush_seeking, FALSE);
+    g_atomic_int_set (&priv->pending_flush_start, FALSE);
+  }
+
+  GST_INFO_OBJECT (self, "seek done, result: %d", res);
+
+  return res;
+}
+
+static gboolean
+_src_event (GstAggregator * self, GstEvent * event)
+{
+  gboolean res = TRUE;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+    {
+      res = _do_seek (self, event);
+      event = NULL;
+      goto done;
+    }
+    case GST_EVENT_NAVIGATION:
+    {
+      /* navigation is rather pointless. */
+      res = FALSE;
+      gst_event_unref (event);
+      goto done;
+    }
+    default:
+    {
+      break;
+    }
+  }
+
+  return _forward_event_to_all_sinkpads (self, event, FALSE);
+
+done:
+  return res;
+}
+
+static gboolean
+src_event_func (GstPad * pad, GstObject * parent, GstEvent * event)
+{
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (parent);
+
+  return klass->src_event (GST_AGGREGATOR (parent), event);
+}
+
+static gboolean
+src_query_func (GstPad * pad, GstObject * parent, GstQuery * query)
+{
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (parent);
+
+  return klass->src_query (GST_AGGREGATOR (parent), query);
+}
+
+static gboolean
+src_activate_mode (GstPad * pad,
+    GstObject * parent, GstPadMode mode, gboolean active)
+{
+  GstAggregator *self = GST_AGGREGATOR (parent);
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (parent);
+
+  if (klass->src_activate) {
+    if (klass->src_activate (self, mode, active) == FALSE) {
+      return FALSE;
+    }
+  }
+
+  if (active == TRUE) {
+    switch (mode) {
+      case GST_PAD_MODE_PUSH:
+      {
+        GST_INFO_OBJECT (pad, "Activating pad!");
+        _start_srcpad_task (self);
+        return TRUE;
+      }
+      default:
+      {
+        GST_ERROR_OBJECT (pad, "Only supported mode is PUSH");
+        return FALSE;
+      }
+    }
+  }
+
+  /* deactivating */
+  GST_INFO_OBJECT (self, "Deactivating srcpad");
+  _stop_srcpad_task (self, FALSE);
+
+  return TRUE;
+}
+
+static gboolean
+_sink_query (GstAggregator * self, GstAggregatorPad * aggpad, GstQuery * query)
+{
+  GstPad *pad = GST_PAD (aggpad);
+
+  return gst_pad_query_default (pad, GST_OBJECT (self), query);
+}
+
+/* GObject vmethods implementations */
+static void
+gst_aggregator_class_init (GstAggregatorClass * klass)
+{
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+
+  aggregator_parent_class = g_type_class_peek_parent (klass);
+  g_type_class_add_private (klass, sizeof (GstAggregatorPrivate));
+
+  GST_DEBUG_CATEGORY_INIT (aggregator_debug, "aggregator",
+      GST_DEBUG_FG_MAGENTA, "GstAggregator");
+
+  klass->sinkpads_type = GST_TYPE_AGGREGATOR_PAD;
+  klass->start = _start;
+  klass->stop = _stop;
+
+  klass->sink_event = _sink_event;
+  klass->sink_query = _sink_query;
+
+  klass->src_event = _src_event;
+  klass->src_query = _src_query;
+
+  gstelement_class->request_new_pad = GST_DEBUG_FUNCPTR (_request_new_pad);
+  gstelement_class->release_pad = GST_DEBUG_FUNCPTR (_release_pad);
+  gstelement_class->change_state = GST_DEBUG_FUNCPTR (_change_state);
+}
+
+static void
+gst_aggregator_init (GstAggregator * self, GstAggregatorClass * klass)
+{
+  GstPadTemplate *pad_template;
+  GstAggregatorPrivate *priv;
+
+  g_return_if_fail (klass->aggregate != NULL);
+
+  self->priv =
+      G_TYPE_INSTANCE_GET_PRIVATE (self, GST_TYPE_AGGREGATOR,
+      GstAggregatorPrivate);
+
+  priv = self->priv;
+
+  pad_template =
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (klass), "src");
+  g_return_if_fail (pad_template != NULL);
+
+  priv->padcount = -1;
+  priv->tags_changed = FALSE;
+  _reset_flow_values (self);
+
+  priv->mcontext = g_main_context_new ();
+  self->srcpad = gst_pad_new_from_template (pad_template, "src");
+
+  gst_pad_set_event_function (self->srcpad,
+      GST_DEBUG_FUNCPTR ((GstPadEventFunction) src_event_func));
+  gst_pad_set_query_function (self->srcpad,
+      GST_DEBUG_FUNCPTR ((GstPadQueryFunction) src_query_func));
+  gst_pad_set_activatemode_function (self->srcpad,
+      GST_DEBUG_FUNCPTR ((GstPadActivateModeFunction) src_activate_mode));
+
+  gst_element_add_pad (GST_ELEMENT (self), self->srcpad);
+}
+
+/* we can't use G_DEFINE_ABSTRACT_TYPE because we need the klass in the _init
+ * method to get to the padtemplates */
+GType
+gst_aggregator_get_type (void)
+{
+  static volatile gsize type = 0;
+
+  if (g_once_init_enter (&type)) {
+    GType _type;
+    static const GTypeInfo info = {
+      sizeof (GstAggregatorClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_aggregator_class_init,
+      NULL,
+      NULL,
+      sizeof (GstAggregator),
+      0,
+      (GInstanceInitFunc) gst_aggregator_init,
+    };
+
+    _type = g_type_register_static (GST_TYPE_ELEMENT,
+        "GstAggregator", &info, G_TYPE_FLAG_ABSTRACT);
+    g_once_init_leave (&type, _type);
+  }
+  return type;
+}
+
+static GstFlowReturn
+_chain (GstPad * pad, GstObject * object, GstBuffer * buffer)
+{
+  GstBuffer *actual_buf = buffer;
+  GstAggregator *self = GST_AGGREGATOR (object);
+  GstAggregatorPrivate *priv = self->priv;
+  GstAggregatorPad *aggpad = GST_AGGREGATOR_PAD (pad);
+  GstAggregatorClass *aggclass = GST_AGGREGATOR_GET_CLASS (object);
+
+  GST_DEBUG_OBJECT (aggpad, "Start chaining a buffer %" GST_PTR_FORMAT, buffer);
+
+  if (g_atomic_int_get (&aggpad->priv->flushing) == TRUE)
+    goto flushing;
+
+  if (g_atomic_int_get (&aggpad->priv->pending_eos) == TRUE)
+    goto eos;
+
+  PAD_LOCK_EVENT (aggpad);
+  if (aggpad->buffer) {
+    GST_DEBUG_OBJECT (aggpad, "Waiting for buffer to be consumed");
+    PAD_WAIT_EVENT (aggpad);
+  }
+  PAD_UNLOCK_EVENT (aggpad);
+
+  if (g_atomic_int_get (&aggpad->priv->flushing) == TRUE)
+    goto flushing;
+
+
+  if (aggclass->clip) {
+    aggclass->clip (self, aggpad, buffer, &actual_buf);
+  }
+
+  PAD_LOCK_EVENT (aggpad);
+  if (aggpad->buffer)
+    gst_buffer_unref (aggpad->buffer);
+  aggpad->buffer = actual_buf;
+  PAD_UNLOCK_EVENT (aggpad);
+
+  _add_aggregate_gsource (self);
+
+  GST_DEBUG_OBJECT (aggpad, "Done chaining");
+
+  return priv->flow_return;
+
+flushing:
+
+  GST_DEBUG_OBJECT (aggpad, "We are flushing");
+
+  return GST_FLOW_FLUSHING;
+
+eos:
+
+  GST_DEBUG_OBJECT (pad, "We are EOS already...");
+
+  return GST_FLOW_EOS;
+}
+
+static gboolean
+pad_query_func (GstPad * pad, GstObject * parent, GstQuery * query)
+{
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (parent);
+
+  return klass->sink_query (GST_AGGREGATOR (parent),
+      GST_AGGREGATOR_PAD (pad), query);
+}
+
+static gboolean
+pad_event_func (GstPad * pad, GstObject * parent, GstEvent * event)
+{
+  GstAggregatorClass *klass = GST_AGGREGATOR_GET_CLASS (parent);
+
+  return klass->sink_event (GST_AGGREGATOR (parent),
+      GST_AGGREGATOR_PAD (pad), event);
+}
+
+static gboolean
+pad_activate_mode_func (GstPad * pad,
+    GstObject * parent, GstPadMode mode, gboolean active)
+{
+  GstAggregatorPad *aggpad = GST_AGGREGATOR_PAD (pad);
+
+  if (active == FALSE) {
+    PAD_LOCK_EVENT (aggpad);
+    g_atomic_int_set (&aggpad->priv->flushing, TRUE);
+    gst_buffer_replace (&aggpad->buffer, NULL);
+    PAD_BROADCAST_EVENT (aggpad);
+    PAD_UNLOCK_EVENT (aggpad);
+  } else {
+    g_atomic_int_set (&aggpad->priv->flushing, FALSE);
+    PAD_LOCK_EVENT (aggpad);
+    PAD_BROADCAST_EVENT (aggpad);
+    PAD_UNLOCK_EVENT (aggpad);
+  }
+
+  return TRUE;
+}
+
+/***********************************
+ * GstAggregatorPad implementation  *
+ ************************************/
+G_DEFINE_TYPE (GstAggregatorPad, gst_aggregator_pad, GST_TYPE_PAD);
+
+static void
+_pad_constructed (GObject * object)
+{
+  GstPad *pad = GST_PAD (object);
+
+  gst_pad_set_chain_function (pad,
+      GST_DEBUG_FUNCPTR ((GstPadChainFunction) _chain));
+  gst_pad_set_event_function (pad,
+      GST_DEBUG_FUNCPTR ((GstPadEventFunction) pad_event_func));
+  gst_pad_set_query_function (pad,
+      GST_DEBUG_FUNCPTR ((GstPadQueryFunction) pad_query_func));
+  gst_pad_set_activatemode_function (pad,
+      GST_DEBUG_FUNCPTR ((GstPadActivateModeFunction) pad_activate_mode_func));
+}
+
+static void
+gst_aggregator_pad_class_init (GstAggregatorPadClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+
+  g_type_class_add_private (klass, sizeof (GstAggregatorPadPrivate));
+
+  gobject_class->constructed = GST_DEBUG_FUNCPTR (_pad_constructed);
+}
+
+static void
+gst_aggregator_pad_init (GstAggregatorPad * pad)
+{
+  pad->priv =
+      G_TYPE_INSTANCE_GET_PRIVATE (pad, GST_TYPE_AGGREGATOR_PAD,
+      GstAggregatorPadPrivate);
+
+  pad->buffer = NULL;
+  g_mutex_init (&pad->priv->event_lock);
+  g_cond_init (&pad->priv->event_cond);
+
+}
+
+/**
+ * gst_aggregator_pad_steal_buffer:
+ * @pad: the pad to get buffer from
+ *
+ * Steal the ref to the buffer currently queued in @pad.
+ *
+ * Returns: (transfer full): The buffer in @pad or NULL if no buffer was
+ *   queued. You should unref the buffer after usage.
+ */
+GstBuffer *
+gst_aggregator_pad_steal_buffer (GstAggregatorPad * pad)
+{
+  GstBuffer *buffer = NULL;
+
+  PAD_LOCK_EVENT (pad);
+  if (pad->buffer) {
+    GST_TRACE_OBJECT (pad, "Consuming buffer");
+    buffer = pad->buffer;
+    pad->buffer = NULL;
+    if (pad->priv->pending_eos) {
+      pad->priv->pending_eos = FALSE;
+      pad->eos = TRUE;
+    }
+    PAD_BROADCAST_EVENT (pad);
+    GST_DEBUG_OBJECT (pad, "Consummed: %" GST_PTR_FORMAT, buffer);
+  }
+  PAD_UNLOCK_EVENT (pad);
+
+  return buffer;
+}
+
+/**
+ * gst_aggregator_pad_get_buffer:
+ * @pad: the pad to get buffer from
+ *
+ * Returns: (transfer full): A reference to the buffer in @pad or
+ * NULL if no buffer was queued. You should unref the buffer after
+ * usage.
+ */
+GstBuffer *
+gst_aggregator_pad_get_buffer (GstAggregatorPad * pad)
+{
+  GstBuffer *buffer = NULL;
+
+  PAD_LOCK_EVENT (pad);
+  if (pad->buffer)
+    buffer = gst_buffer_ref (pad->buffer);
+  PAD_UNLOCK_EVENT (pad);
+
+  return buffer;
+}
+
+/**
+ * gst_aggregator_merge_tags:
+ * @self: a #GstAggregator
+ * @tags: a #GstTagList to merge
+ * @mode: the #GstTagMergeMode to use
+ *
+ * Adds tags to so-called pending tags, which will be processed
+ * before pushing out data downstream.
+ *
+ * Note that this is provided for convenience, and the subclass is
+ * not required to use this and can still do tag handling on its own.
+ *
+ * MT safe.
+ */
+void
+gst_aggregator_merge_tags (GstAggregator * self,
+    const GstTagList * tags, GstTagMergeMode mode)
+{
+  GstTagList *otags;
+
+  g_return_if_fail (GST_IS_AGGREGATOR (self));
+  g_return_if_fail (tags == NULL || GST_IS_TAG_LIST (tags));
+
+  /* FIXME Check if we can use OBJECT lock here! */
+  GST_OBJECT_LOCK (self);
+  if (tags)
+    GST_DEBUG_OBJECT (self, "merging tags %" GST_PTR_FORMAT, tags);
+  otags = self->priv->tags;
+  self->priv->tags = gst_tag_list_merge (self->priv->tags, tags, mode);
+  if (otags)
+    gst_tag_list_unref (otags);
+  self->priv->tags_changed = TRUE;
+  GST_OBJECT_UNLOCK (self);
+}
diff --git a/gst-libs/gst/base/gstaggregator.h b/gst-libs/gst/base/gstaggregator.h
new file mode 100644
index 000000000..3965ccc48
--- /dev/null
+++ b/gst-libs/gst/base/gstaggregator.h
@@ -0,0 +1,256 @@
+/* GStreamer
+ * Copyright (C) 2014 Mathieu Duponchelle <mathieu.duponchelle@oencreed.com>
+ * Copyright (C) 2014 Thibault Saunier <tsaunier@gnome.org>
+ *
+ * gstaggregator.c:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_AGGREGATOR_H__
+#define __GST_AGGREGATOR_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+/**************************
+ * GstAggregator Structs  *
+ *************************/
+
+typedef struct _GstAggregator GstAggregator;
+typedef struct _GstAggregatorPrivate GstAggregatorPrivate;
+typedef struct _GstAggregatorClass GstAggregatorClass;
+
+/************************
+ * GstAggregatorPad API *
+ ***********************/
+
+#define GST_TYPE_AGGREGATOR_PAD            (gst_aggregator_pad_get_type())
+#define GST_AGGREGATOR_PAD(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AGGREGATOR_PAD, GstAggregatorPad))
+#define GST_AGGREGATOR_PAD_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AGGREGATOR_PAD, GstAggregatorPadClass))
+#define GST_AGGREGATOR_PAD_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),GST_TYPE_AGGREGATOR_PAD, GstAggregatorPadClass))
+#define GST_IS_AGGREGATOR_PAD(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AGGREGATOR_PAD))
+#define GST_IS_AGGREGATOR_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AGGREGATOR_PAD))
+
+/****************************
+ * GstAggregatorPad Structs *
+ ***************************/
+
+typedef struct _GstAggregatorPad GstAggregatorPad;
+typedef struct _GstAggregatorPadClass GstAggregatorPadClass;
+typedef struct _GstAggregatorPadPrivate GstAggregatorPadPrivate;
+
+/**
+ * GstAggregatorPad:
+ * @buffer: currently queued buffer.
+ * @segment: last segment received.
+ *
+ * The implementation the GstPad to use with #GstAggregator
+ */
+struct _GstAggregatorPad
+{
+  GstPad                       parent;
+
+  GstBuffer                 *  buffer;
+  GstSegment                   segment;
+  gboolean                     eos;
+
+  /* < Private > */
+  GstAggregatorPadPrivate   *  priv;
+
+  gpointer _gst_reserved[GST_PADDING];
+};
+
+/**
+ * GstAggregatorPadClass:
+ * @flush:    Optional
+ *            Called when the pad has received a flush stop, this is the place
+ *            to flush any information specific to the pad, it allows for individual
+ *            pads to be flushed while others might not be.
+ *
+ */
+struct _GstAggregatorPadClass
+{
+  GstPadClass   parent_class;
+
+  GstFlowReturn (*flush)     (GstAggregatorPad * aggpad, GstAggregator * aggregator);
+
+  /*< private >*/
+  gpointer      _gst_reserved[GST_PADDING];
+};
+
+GType gst_aggregator_pad_get_type           (void);
+
+/****************************
+ * GstAggregatorPad methods *
+ ***************************/
+
+GstBuffer * gst_aggregator_pad_steal_buffer (GstAggregatorPad *  pad);
+GstBuffer * gst_aggregator_pad_get_buffer   (GstAggregatorPad *  pad);
+
+/*********************
+ * GstAggregator API *
+ ********************/
+
+#define GST_TYPE_AGGREGATOR            (gst_aggregator_get_type())
+#define GST_AGGREGATOR(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AGGREGATOR,GstAggregator))
+#define GST_AGGREGATOR_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AGGREGATOR,GstAggregatorClass))
+#define GST_AGGREGATOR_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),GST_TYPE_AGGREGATOR,GstAggregatorClass))
+#define GST_IS_AGGREGATOR(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AGGREGATOR))
+#define GST_IS_AGGREGATOR_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AGGREGATOR))
+
+#define GST_FLOW_CUSTOM_SUCCESS        GST_FLOW_NOT_HANDLED
+
+/**
+ * GstAggregator:
+ * @aggregator_pads: #GList of #GstAggregatorPad managed by this #GstAggregator.
+ *
+ * Collectpads object.
+ */
+struct _GstAggregator
+{
+  GstElement               parent;
+
+  GstPad                *  srcpad;
+
+  GstSegment               segment;
+
+  /*< private >*/
+  GstAggregatorPrivate  *  priv;
+
+  gpointer                 _gst_reserved[GST_PADDING];
+};
+
+/**
+ * GstAggregatorClass:
+ * @sinkpads_type:  Optional.
+ *                  The type of the pads that should be created when
+ *                  GstElement.request_new_pad is called.
+ * @flush:          Optional.
+ *                  Called after a succesful flushing seek, once all the flush
+ *                  stops have been received. Flush pad-specific data in
+ *                  #GstAggregatorPad->flush.
+ * @clip:           Optional.
+ *                  Called when a buffer is received on a sink pad, the task
+ *                  of clipping it and translating it to the current segment
+ *                  falls on the subclass.
+ * @sink_event:     Optional.
+ *                  Called when an event is received on a sink pad, the subclass
+ *                  should always chain up.
+ * @sink_query:     Optional.
+ *                  Called when a query is received on a sink pad, the subclass
+ *                  should always chain up.
+ * @src_event:      Optional.
+ *                  Called when an event is received on the src pad, the subclass
+ *                  should always chain up.
+ * @src_query:      Optional.
+ *                  Called when a query is received on the src pad, the subclass
+ *                  should always chain up.
+ * @src_activate:   Optional.
+ *                  Called when the src pad is activated, it will start/stop its
+ *                  pad task right after that call.
+ * @aggregate:      Mandatory.
+ *                  Called when buffers are queued on all sinkpads. Classes
+ *                  should iterate the GstElement->sinkpads and peek or steal
+ *                  buffers from the #GstAggregatorPads. If the subclass returns
+ *                  GST_FLOW_EOS, sending of the eos event will be taken care
+ *                  of. Once / if a buffer has been constructed from the
+ *                  aggregated buffers, the subclass should call _finish_buffer.
+ * @stop:           Optional.
+ *                  Should be linked up first. Called when the
+ *                  element goes from PAUSED to READY. The subclass should free
+ *                  all resources and reset its state.
+ * @start:          Optional.
+ *                  Should be linked up first. Called when the element goes from
+ *                  READY to PAUSED. The subclass should get ready to process
+ *                  aggregated buffers.
+ *
+ * The aggregator base class will handle in a thread-safe way all manners of
+ * concurrent flushes, seeks, pad additions and removals, leaving to the
+ * subclass the responsibility of clipping buffers, and aggregating buffers in
+ * the way the implementor sees fit.
+ *
+ * It will also take care of event ordering (stream-start, segment, eos).
+ *
+ * Basically, a basic implementation will override @aggregate, and call
+ * _finish_buffer from inside that function.
+ */
+struct _GstAggregatorClass {
+  GstElementClass   parent_class;
+
+  GType             sinkpads_type;
+
+  GstFlowReturn     (*flush)          (GstAggregator    *  aggregator);
+
+  GstFlowReturn     (*clip)           (GstAggregator    *  agg,
+                                       GstAggregatorPad *  bpad,
+                                       GstBuffer        *  buf,
+                                       GstBuffer        ** outbuf);
+
+  /* sinkpads virtual methods */
+  gboolean          (*sink_event)     (GstAggregator    *  aggregate,
+                                       GstAggregatorPad *  bpad,
+                                       GstEvent         *  event);
+
+  gboolean          (*sink_query)     (GstAggregator    *  aggregate,
+                                       GstAggregatorPad *  bpad,
+                                       GstQuery         *  query);
+
+  /* srcpad virtual methods */
+  gboolean          (*src_event)      (GstAggregator    *  aggregate,
+                                       GstEvent         *  event);
+
+  gboolean          (*src_query)      (GstAggregator    *  aggregate,
+                                       GstQuery         *  query);
+
+  gboolean          (*src_activate)   (GstAggregator    *  aggregator,
+                                       GstPadMode          mode,
+                                       gboolean            active);
+
+  GstFlowReturn     (*aggregate)      (GstAggregator    *  aggregator);
+
+  gboolean          (*stop)           (GstAggregator    *  aggregator);
+
+  gboolean          (*start)          (GstAggregator    *  aggregator);
+
+  /*< private >*/
+  gpointer          _gst_reserved[GST_PADDING];
+};
+
+/*************************
+ * GstAggregator methods *
+ ************************/
+
+GstFlowReturn  gst_aggregator_finish_buffer         (GstAggregator                *  agg,
+                                                     GstBuffer                    *  buffer);
+void           gst_aggregator_set_src_caps          (GstAggregator                *  agg,
+                                                     GstCaps                      *  caps);
+
+GType gst_aggregator_get_type(void);
+
+/* API that should eventually land in GstElement itself*/
+typedef gboolean (*GstAggregatorPadForeachFunc)    (GstAggregator                 *  self,
+                                                    GstPad                        *  pad,
+                                                    gpointer                         user_data);
+gboolean gst_aggregator_iterate_sinkpads           (GstAggregator                 *  self,
+                                                    GstAggregatorPadForeachFunc      func,
+                                                    gpointer                         user_data);
+
+
+G_END_DECLS
+
+#endif /* __GST_AGGREGATOR_H__ */
diff --git a/pkgconfig/gstreamer-bad-base-uninstalled.pc.in b/pkgconfig/gstreamer-bad-base-uninstalled.pc.in
new file mode 100644
index 000000000..560eb13bd
--- /dev/null
+++ b/pkgconfig/gstreamer-bad-base-uninstalled.pc.in
@@ -0,0 +1,15 @@
+prefix=
+exec_prefix=
+libdir=${pcfiledir}/../gst-libs/gst/base
+includedir=${pcfiledir}/../gst-libs
+pluginsdir=${pcfiledir}/..
+
+Name: GStreamer bad base classes, uninstalled
+Description: Bad base classes for GStreamer elements, Not Installed
+Version: @VERSION@
+Requires: gstreamer-@GST_API_VERSION@
+
+Libs: -L${libdir} ${libdir}/libgstbadbase-@GST_API_VERSION@.la @BADBASE_LIBS@
+Cflags: -I${includedir} -I@srcdir@/.. @BADBASE_CFLAGS@
+
+libraries=badbase
diff --git a/pkgconfig/gstreamer-bad-base.pc.in b/pkgconfig/gstreamer-bad-base.pc.in
new file mode 100644
index 000000000..a03013b2b
--- /dev/null
+++ b/pkgconfig/gstreamer-bad-base.pc.in
@@ -0,0 +1,15 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/gstreamer-@GST_API_VERSION@
+pluginsdir=@libdir@/gstreamer-@GST_API_VERSION@
+
+Name: GStreamer bad base classes, uninstalled
+Description: Bad base classes for GStreamer elements, Not Installed
+Version: @VERSION@
+Requires: gstreamer-@GST_API_VERSION@
+
+Libs: -L${libdir} ${libdir}/libgstbadbase-@GST_API_VERSION@.la @BADBASE_LIBS@
+Cflags: -I${includedir} -I@srcdir@/.. @BADBASE_CFLAGS@
+
+libraries=badbase
diff --git a/tests/check/Makefile.am b/tests/check/Makefile.am
index e7b77edba..6233d013c 100644
--- a/tests/check/Makefile.am
+++ b/tests/check/Makefile.am
@@ -244,6 +244,7 @@ check_PROGRAMS = \
 	libs/mpegts \
 	libs/h264parser \
 	libs/vp8parser \
+	libs/aggregator \
 	$(check_uvch264) \
 	libs/vc1parser \
 	$(check_schro) \
@@ -455,6 +456,16 @@ libs_gstglupload_LDADD = \
 	$(GST_PLUGINS_BASE_LIBS) -lgstvideo-$(GST_API_VERSION) \
 	$(GST_BASE_LIBS) $(GST_LIBS) $(LDADD)
 
+libs_aggregator_LDADD = \
+	$(top_builddir)/gst-libs/gst/base/libgstbadbase-@GST_API_VERSION@.la \
+	$(GST_PLUGINS_BASE_LIBS) \
+	$(GST_BASE_LIBS) $(GST_LIBS) $(LDADD)
+
+libs_aggregator_CFLAGS = \
+	$(GST_PLUGINS_BAD_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) \
+	-DGST_USE_UNSTABLE_API \
+	$(GST_BASE_CFLAGS) $(GST_CFLAGS) $(AM_CFLAGS)
+
 distclean-local-orc:
 	rm -rf orc
 
diff --git a/tests/check/libs/aggregator.c b/tests/check/libs/aggregator.c
new file mode 100644
index 000000000..c0b0bdbba
--- /dev/null
+++ b/tests/check/libs/aggregator.c
@@ -0,0 +1,1017 @@
+/*
+ * aggregator.c - GstAggregator testsuite
+ * Copyright (C) 2006 Alessandro Decina <alessandro.d@gmail.com>
+ * Copyright (C) 2014 Mathieu Duponchelle <mathieu.duponchelle@oencreed.com>
+ * Copyright (C) 2014 Thibault Saunier <tsaunier@opencreed.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <gst/check/gstcheck.h>
+#include <gst/base/gstaggregator.h>
+
+/* dummy aggregator based element */
+
+#define GST_TYPE_TEST_AGGREGATOR            (gst_test_aggregator_get_type ())
+#define GST_TEST_AGGREGATOR(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_TEST_AGGREGATOR, GstTestAggregator))
+#define GST_TEST_AGGREGATOR_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_TEST_AGGREGATOR, GstTestAggregatorClass))
+#define GST_TEST_AGGREGATOR_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_TEST_AGGREGATOR, GstTestAggregatorClass))
+
+#define fail_error_message(msg)     \
+  G_STMT_START {        \
+    GError *error;        \
+    gst_message_parse_error(msg, &error, NULL);       \
+    fail_unless(FALSE, "Error Message from %s : %s",      \
+    GST_OBJECT_NAME (GST_MESSAGE_SRC(msg)), error->message); \
+    g_error_free (error);           \
+  } G_STMT_END;
+
+typedef struct _GstTestAggregator GstTestAggregator;
+typedef struct _GstTestAggregatorClass GstTestAggregatorClass;
+
+static GType gst_test_aggregator_get_type (void);
+
+#define BUFFER_DURATION 100000000       /* 10 frames per second */
+
+struct _GstTestAggregator
+{
+  GstAggregator parent;
+
+  guint64 timestamp;
+};
+
+struct _GstTestAggregatorClass
+{
+  GstAggregatorClass parent_class;
+};
+
+static GstFlowReturn
+gst_test_aggregator_aggregate (GstAggregator * aggregator)
+{
+  GstIterator *iter;
+  gboolean all_eos = TRUE;
+  GstTestAggregator *testagg;
+  GstBuffer *buf;
+
+  gboolean done_iterating = FALSE;
+
+  testagg = GST_TEST_AGGREGATOR (aggregator);
+
+  iter = gst_element_iterate_sink_pads (GST_ELEMENT (testagg));
+  while (!done_iterating) {
+    GstBuffer *buffer;
+    GValue value = { 0, };
+    GstAggregatorPad *pad;
+
+    switch (gst_iterator_next (iter, &value)) {
+      case GST_ITERATOR_OK:
+        pad = g_value_get_object (&value);
+
+        if (pad->eos == FALSE)
+          all_eos = FALSE;
+        buffer = gst_aggregator_pad_steal_buffer (pad);
+        gst_buffer_replace (&buffer, NULL);
+
+        g_value_reset (&value);
+        break;
+      case GST_ITERATOR_RESYNC:
+        gst_iterator_resync (iter);
+        break;
+      case GST_ITERATOR_ERROR:
+        GST_WARNING_OBJECT (testagg, "Sinkpads iteration error");
+        done_iterating = TRUE;
+        break;
+      case GST_ITERATOR_DONE:
+        done_iterating = TRUE;
+        break;
+    }
+  }
+  gst_iterator_free (iter);
+
+  if (all_eos == TRUE) {
+    GST_ERROR_OBJECT (testagg, "no data available, must be EOS");
+    gst_pad_push_event (aggregator->srcpad, gst_event_new_eos ());
+    return GST_FLOW_EOS;
+  }
+
+  buf = gst_buffer_new ();
+  GST_BUFFER_TIMESTAMP (buf) = testagg->timestamp;
+  GST_BUFFER_DURATION (buf) = BUFFER_DURATION;
+  testagg->timestamp += BUFFER_DURATION;
+
+  gst_aggregator_finish_buffer (aggregator, buf);
+
+  /* We just check finish_frame return FLOW_OK */
+  return GST_FLOW_OK;
+}
+
+#define gst_test_aggregator_parent_class parent_class
+G_DEFINE_TYPE (GstTestAggregator, gst_test_aggregator, GST_TYPE_AGGREGATOR);
+
+static void
+gst_test_aggregator_class_init (GstTestAggregatorClass * klass)
+{
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstAggregatorClass *base_aggregator_class = (GstAggregatorClass *) klass;
+
+  static GstStaticPadTemplate _src_template =
+      GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
+      GST_STATIC_CAPS_ANY);
+
+  static GstStaticPadTemplate _sink_template =
+      GST_STATIC_PAD_TEMPLATE ("sink_%u", GST_PAD_SINK, GST_PAD_REQUEST,
+      GST_STATIC_CAPS_ANY);
+
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&_src_template));
+
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&_sink_template));
+
+  gst_element_class_set_static_metadata (gstelement_class, "Aggregator",
+      "Testing", "Combine N buffers", "Stefan Sauer <ensonic@users.sf.net>");
+
+  base_aggregator_class->aggregate =
+      GST_DEBUG_FUNCPTR (gst_test_aggregator_aggregate);
+}
+
+static void
+gst_test_aggregator_init (GstTestAggregator * self)
+{
+  GstAggregator *agg = GST_AGGREGATOR (self);
+  gst_segment_init (&agg->segment, GST_FORMAT_BYTES);
+  self->timestamp = 0;
+}
+
+static gboolean
+gst_test_aggregator_plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "testaggregator", GST_RANK_NONE,
+      GST_TYPE_TEST_AGGREGATOR);
+}
+
+static gboolean
+gst_test_aggregator_plugin_register (void)
+{
+  return gst_plugin_register_static (GST_VERSION_MAJOR,
+      GST_VERSION_MINOR,
+      "testaggregator",
+      "Combine buffers",
+      gst_test_aggregator_plugin_init,
+      VERSION, GST_LICENSE, PACKAGE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN);
+}
+
+typedef struct
+{
+  GstEvent *event;
+  GstBuffer *buffer;
+  GstElement *aggregator;
+  GstPad *sinkpad, *srcpad;
+  GstFlowReturn expected_result;
+
+  /*                       ------------------
+   * -----------   --------|--              |
+   * | srcpad | -- | sinkpad |  aggregator  |
+   * -----------   --------|--              |
+   *                       ------------------
+   *  This is for 1 Chain, we can have several
+   */
+} ChainData;
+
+typedef struct
+{
+  GMainLoop *ml;
+  GstPad *srcpad,               /* srcpad of the GstAggregator */
+   *sinkpad;                    /* fake sinkpad to which GstAggregator.srcpad is linked */
+  guint timeout_id;
+  GstElement *aggregator;
+
+  /* -----------------|
+   * |             ----------    -----------
+   * | aggregator  | srcpad | -- | sinkpad |
+   * |             ----------    -----------
+   * -----------------|
+   */
+
+  gint flush_start_events, flush_stop_events;
+} TestData;
+
+static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+
+static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+
+static gpointer
+push_buffer (gpointer user_data)
+{
+  GstFlowReturn flow;
+  GstCaps *caps;
+  ChainData *chain_data = (ChainData *) user_data;
+  GstSegment segment;
+
+  gst_pad_push_event (chain_data->srcpad, gst_event_new_stream_start ("test"));
+
+  caps = gst_caps_new_empty_simple ("foo/x-bar");
+  gst_pad_push_event (chain_data->srcpad, gst_event_new_caps (caps));
+  gst_caps_unref (caps);
+
+  gst_segment_init (&segment, GST_FORMAT_TIME);
+  gst_pad_push_event (chain_data->srcpad, gst_event_new_segment (&segment));
+
+  GST_DEBUG ("Pushing buffer on pad: %s:%s",
+      GST_DEBUG_PAD_NAME (chain_data->sinkpad));
+  flow = gst_pad_push (chain_data->srcpad, chain_data->buffer);
+  fail_unless (flow == chain_data->expected_result,
+      "got flow %s instead of %s on %s:%s", gst_flow_get_name (flow),
+      gst_flow_get_name (chain_data->expected_result),
+      GST_DEBUG_PAD_NAME (chain_data->sinkpad));
+  chain_data->buffer = NULL;
+
+  return NULL;
+}
+
+static gpointer
+push_event (gpointer user_data)
+{
+  ChainData *chain_data = (ChainData *) user_data;
+
+  GST_ERROR_OBJECT (chain_data->srcpad, "Pushing event: %"
+      GST_PTR_FORMAT, chain_data->event);
+  fail_unless (gst_pad_push_event (chain_data->srcpad,
+          chain_data->event) == TRUE);
+
+  return NULL;
+}
+
+static gboolean
+_aggregate_timeout (GMainLoop * ml)
+{
+  g_main_loop_quit (ml);
+
+  fail_unless ("No buffer found on aggregator.srcpad -> TIMEOUT" == NULL);
+
+  return FALSE;
+}
+
+static gboolean
+_quit (GMainLoop * ml)
+{
+  GST_DEBUG ("QUITING ML");
+  g_main_loop_quit (ml);
+
+  return G_SOURCE_REMOVE;
+}
+
+static GstPadProbeReturn
+_aggregated_cb (GstPad * pad, GstPadProbeInfo * info, GMainLoop * ml)
+{
+  GST_DEBUG ("SHould quit ML");
+  g_idle_add ((GSourceFunc) _quit, ml);
+
+  return GST_PAD_PROBE_REMOVE;
+}
+
+static GstPadProbeReturn
+downstream_probe_cb (GstPad * pad, GstPadProbeInfo * info, TestData * test)
+{
+  GST_DEBUG ("PROBING ");
+  if (info->type & GST_PAD_PROBE_TYPE_EVENT_FLUSH) {
+    if (GST_EVENT_TYPE (GST_PAD_PROBE_INFO_EVENT (info)) ==
+        GST_EVENT_FLUSH_START) {
+
+      g_atomic_int_inc (&test->flush_start_events);
+      GST_DEBUG ("==========> FLUSH: %i", test->flush_start_events);
+    } else if (GST_EVENT_TYPE (GST_PAD_PROBE_INFO_EVENT (info)) ==
+        GST_EVENT_FLUSH_STOP)
+      g_atomic_int_inc (&test->flush_stop_events);
+  }
+
+  return GST_PAD_PROBE_DROP;
+}
+
+/*
+ * Not thread safe, will create a new ChainData which contains
+ * an activated src pad linked to a requested sink pad of @agg, and
+ * a newly allocated buffer ready to be pushed. Caller needs to
+ * clear with _chain_data_clear after.
+ */
+static void
+_chain_data_init (ChainData * data, GstElement * agg)
+{
+  static gint num_src_pads = 0;
+  gchar *pad_name = g_strdup_printf ("src%d", num_src_pads);
+
+  num_src_pads += 1;
+
+  data->srcpad = gst_pad_new_from_static_template (&srctemplate, pad_name);
+  g_free (pad_name);
+  gst_pad_set_active (data->srcpad, TRUE);
+  data->aggregator = agg;
+  data->buffer = gst_buffer_new ();
+  data->sinkpad = gst_element_get_request_pad (agg, "sink_%u");
+  fail_unless (GST_IS_PAD (data->sinkpad));
+  fail_unless (gst_pad_link (data->srcpad, data->sinkpad) == GST_PAD_LINK_OK);
+}
+
+static void
+_chain_data_clear (ChainData * data)
+{
+  if (data->buffer)
+    gst_buffer_unref (data->buffer);
+  if (data->srcpad)
+    gst_object_unref (data->srcpad);
+  if (data->sinkpad)
+    gst_object_unref (data->sinkpad);
+}
+
+static void
+_test_data_init (TestData * test, gboolean needs_flushing)
+{
+  test->aggregator = gst_element_factory_make ("testaggregator", NULL);
+  gst_element_set_state (test->aggregator, GST_STATE_PLAYING);
+  test->ml = g_main_loop_new (NULL, TRUE);
+  test->srcpad = GST_AGGREGATOR (test->aggregator)->srcpad;
+
+  GST_DEBUG ("Srcpad: %p", test->srcpad);
+
+  if (needs_flushing) {
+    static gint num_sink_pads = 0;
+    gchar *pad_name = g_strdup_printf ("sink%d", num_sink_pads);
+
+    num_sink_pads += 1;
+    test->sinkpad = gst_pad_new_from_static_template (&sinktemplate, pad_name);
+    g_free (pad_name);
+    fail_unless (gst_pad_link (test->srcpad, test->sinkpad) == GST_PAD_LINK_OK);
+    gst_pad_add_probe (test->srcpad, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM |
+        GST_PAD_PROBE_TYPE_DATA_DOWNSTREAM |
+        GST_PAD_PROBE_TYPE_EVENT_FLUSH,
+        (GstPadProbeCallback) downstream_probe_cb, test, NULL);
+  } else {
+    gst_pad_add_probe (test->srcpad, GST_PAD_PROBE_TYPE_BUFFER,
+        (GstPadProbeCallback) _aggregated_cb, test->ml, NULL);
+  }
+
+
+  test->timeout_id =
+      g_timeout_add (1000, (GSourceFunc) _aggregate_timeout, test->ml);
+}
+
+static void
+_test_data_clear (TestData * test)
+{
+  gst_element_set_state (test->aggregator, GST_STATE_NULL);
+  gst_object_unref (test->aggregator);
+
+  g_main_loop_unref (test->ml);
+}
+
+GST_START_TEST (test_aggregate)
+{
+  GThread *thread1, *thread2;
+
+  ChainData data1 = { 0, };
+  ChainData data2 = { 0, };
+  TestData test = { 0, };
+
+  _test_data_init (&test, FALSE);
+  _chain_data_init (&data1, test.aggregator);
+  _chain_data_init (&data2, test.aggregator);
+
+  thread1 = g_thread_try_new ("gst-check", push_buffer, &data1, NULL);
+  thread2 = g_thread_try_new ("gst-check", push_buffer, &data2, NULL);
+
+  g_main_loop_run (test.ml);
+  g_source_remove (test.timeout_id);
+
+
+  /* these will return immediately as when the data is popped the threads are
+   * unlocked and will terminate */
+  g_thread_join (thread1);
+  g_thread_join (thread2);
+
+  _chain_data_clear (&data1);
+  _chain_data_clear (&data2);
+  _test_data_clear (&test);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_aggregate_eos)
+{
+  GThread *thread1, *thread2;
+
+  ChainData data1 = { 0, };
+  ChainData data2 = { 0, };
+  TestData test = { 0, };
+
+  _test_data_init (&test, FALSE);
+  _chain_data_init (&data1, test.aggregator);
+  _chain_data_init (&data2, test.aggregator);
+
+  data2.event = gst_event_new_eos ();
+
+  thread1 = g_thread_try_new ("gst-check", push_buffer, &data1, NULL);
+  thread2 = g_thread_try_new ("gst-check", push_event, &data2, NULL);
+
+  g_main_loop_run (test.ml);
+  g_source_remove (test.timeout_id);
+
+  /* these will return immediately as when the data is popped the threads are
+   * unlocked and will terminate */
+  g_thread_join (thread1);
+  g_thread_join (thread2);
+
+  _chain_data_clear (&data1);
+  _chain_data_clear (&data2);
+  _test_data_clear (&test);
+}
+
+GST_END_TEST;
+
+#define NUM_BUFFERS 3
+static void
+handoff (GstElement * fakesink, GstBuffer * buf, GstPad * pad, guint * count)
+{
+  *count = *count + 1;
+  GST_DEBUG ("HANDOFF: %i", *count);
+}
+
+/* Test a linear pipeline using aggregator */
+GST_START_TEST (test_linear_pipeline)
+{
+  GstBus *bus;
+  GstMessage *msg;
+  GstElement *pipeline, *src, *agg, *sink;
+
+  gint count = 0;
+
+  pipeline = gst_pipeline_new ("pipeline");
+  src = gst_check_setup_element ("fakesrc");
+  g_object_set (src, "num-buffers", NUM_BUFFERS, "sizetype", 2, "sizemax", 4,
+      NULL);
+  agg = gst_check_setup_element ("testaggregator");
+  sink = gst_check_setup_element ("fakesink");
+  g_object_set (sink, "signal-handoffs", TRUE, NULL);
+  g_signal_connect (sink, "handoff", (GCallback) handoff, &count);
+
+  fail_unless (gst_bin_add (GST_BIN (pipeline), src));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), agg));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), sink));
+  fail_unless (gst_element_link (src, agg));
+  fail_unless (gst_element_link (agg, sink));
+
+  bus = gst_element_get_bus (pipeline);
+  fail_if (bus == NULL);
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  msg = gst_bus_poll (bus, GST_MESSAGE_EOS | GST_MESSAGE_ERROR, -1);
+  fail_if (GST_MESSAGE_TYPE (msg) != GST_MESSAGE_EOS);
+  gst_message_unref (msg);
+
+  fail_unless_equals_int (count, NUM_BUFFERS);
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (bus);
+  gst_object_unref (pipeline);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_two_src_pipeline)
+{
+  GstBus *bus;
+  GstMessage *msg;
+  GstElement *pipeline, *src, *src1, *agg, *sink;
+
+  gint count = 0;
+
+  pipeline = gst_pipeline_new ("pipeline");
+  src = gst_element_factory_make ("fakesrc", NULL);
+  g_object_set (src, "num-buffers", NUM_BUFFERS, "sizetype", 2, "sizemax", 4,
+      NULL);
+
+  src1 = gst_element_factory_make ("fakesrc", NULL);
+  g_object_set (src1, "num-buffers", NUM_BUFFERS + 1, "sizetype", 2, "sizemax",
+      4, NULL);
+
+  agg = gst_check_setup_element ("testaggregator");
+  sink = gst_check_setup_element ("fakesink");
+  g_object_set (sink, "signal-handoffs", TRUE, NULL);
+  g_signal_connect (sink, "handoff", (GCallback) handoff, &count);
+
+  fail_unless (gst_bin_add (GST_BIN (pipeline), src));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), src1));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), agg));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), sink));
+  fail_unless (gst_element_link (src, agg));
+  fail_unless (gst_element_link (src1, agg));
+  fail_unless (gst_element_link (agg, sink));
+
+  bus = gst_element_get_bus (pipeline);
+  fail_if (bus == NULL);
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  msg = gst_bus_poll (bus, GST_MESSAGE_EOS | GST_MESSAGE_ERROR, -1);
+  fail_if (GST_MESSAGE_TYPE (msg) != GST_MESSAGE_EOS);
+  gst_message_unref (msg);
+
+  fail_unless_equals_int (count, NUM_BUFFERS + 1);
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (bus);
+  gst_object_unref (pipeline);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_flushing_seek)
+{
+  GstEvent *event;
+  GThread *thread1, *thread2;
+
+  ChainData data1 = { 0, };
+  ChainData data2 = { 0, };
+  TestData test = { 0, };
+
+  _test_data_init (&test, TRUE);
+
+  /* Queue a buffer in agg:sink_1. Then do a flushing seek and check that the
+   * new flushing seek logic is triggered. On the first FLUSH_START call the
+   * buffers queued in collectpads should get flushed. Only one FLUSH_START and
+   * one FLUSH_STOP should be forwarded downstream.
+   */
+  _chain_data_init (&data1, test.aggregator);
+  _chain_data_init (&data2, test.aggregator);
+  GST_BUFFER_TIMESTAMP (data2.buffer) = 0;
+
+  gst_segment_init (&GST_AGGREGATOR (test.aggregator)->segment,
+      GST_FORMAT_TIME);
+  /* now do a successful flushing seek */
+  event = gst_event_new_seek (1, GST_FORMAT_TIME, GST_SEEK_FLAG_FLUSH,
+      GST_SEEK_TYPE_SET, 0, GST_SEEK_TYPE_SET, 10 * GST_SECOND);
+  fail_unless (gst_pad_send_event (test.srcpad, event));
+
+  /* flushing starts once one of the upstream elements sends the first
+   * FLUSH_START */
+  fail_unless_equals_int (test.flush_start_events, 0);
+  fail_unless_equals_int (test.flush_stop_events, 0);
+
+  /* flush ogg:sink_0. This flushs collectpads, calls ::flush() and sends
+   * FLUSH_START downstream */
+  GST_DEBUG ("Flushing: %s:%s", GST_DEBUG_PAD_NAME (data2.sinkpad));
+  fail_unless (gst_pad_push_event (data2.srcpad, gst_event_new_flush_start ()));
+
+  /* expect this buffer to be flushed */
+  data2.expected_result = GST_FLOW_FLUSHING;
+  thread2 = g_thread_try_new ("gst-check", push_buffer, &data2, NULL);
+
+  fail_unless (gst_pad_push_event (data1.srcpad, gst_event_new_flush_start ()));
+  fail_unless_equals_int (test.flush_start_events, 1);
+  fail_unless_equals_int (test.flush_stop_events, 0);
+
+  /* the first FLUSH_STOP is not forwarded downstream */
+  fail_unless (gst_pad_push_event (data1.srcpad,
+          gst_event_new_flush_stop (TRUE)));
+  fail_unless_equals_int (test.flush_start_events, 1);
+  fail_unless_equals_int (test.flush_stop_events, 0);
+
+  /* at this point even the other pad agg:sink_1 should be flushing so thread2
+   * should have stopped */
+  g_thread_join (thread2);
+
+  /* push a buffer on agg:sink_0 to trigger one collect after flushing to verify
+   * that flushing completes once all the pads have been flushed */
+  thread1 = g_thread_try_new ("gst-check", push_buffer, &data1, NULL);
+
+  /* flush agg:sink_1 as well. This completes the flushing seek so a FLUSH_STOP is
+   * sent downstream */
+  gst_pad_push_event (data2.srcpad, gst_event_new_flush_stop (TRUE));
+
+  /* and the last FLUSH_STOP is forwarded downstream */
+  fail_unless_equals_int (test.flush_start_events, 1);
+
+  /*  Check collected */
+  gst_pad_add_probe (test.srcpad, GST_PAD_PROBE_TYPE_BUFFER,
+      (GstPadProbeCallback) _aggregated_cb, test.ml, NULL);
+
+  data2.event = gst_event_new_eos ();
+  thread2 = g_thread_try_new ("gst-check", push_event, &data2, NULL);
+
+  g_main_loop_run (test.ml);
+  g_source_remove (test.timeout_id);
+
+  fail_unless_equals_int (test.flush_stop_events, 1);
+
+  /* these will return immediately as at this point the threads have been
+   * unlocked and are finished */
+  g_thread_join (thread1);
+  g_thread_join (thread2);
+
+  _test_data_clear (&test);
+
+}
+
+GST_END_TEST;
+
+static void
+infinite_seek (guint num_srcs, guint num_seeks)
+{
+  GstBus *bus;
+  GstMessage *message;
+  GstElement *pipeline, *src, *agg, *sink;
+
+  gint count = 0, i;
+  gboolean seek_res, carry_on = TRUE;
+
+  gst_init (NULL, NULL);
+
+  pipeline = gst_pipeline_new ("pipeline");
+
+  agg = gst_check_setup_element ("testaggregator");
+  sink = gst_check_setup_element ("fakesink");
+
+  fail_unless (gst_bin_add (GST_BIN (pipeline), agg));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), sink));
+  fail_unless (gst_element_link (agg, sink));
+
+  for (i = 0; i < num_srcs; i++) {
+    src = gst_element_factory_make ("fakesrc", NULL);
+    g_object_set (src, "sizetype", 2, "sizemax", 4, NULL);
+    fail_unless (gst_bin_add (GST_BIN (pipeline), src));
+    fail_unless (gst_element_link (src, agg));
+  }
+
+  bus = gst_element_get_bus (pipeline);
+  fail_if (bus == NULL);
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+  while (count < num_seeks && carry_on) {
+    message = gst_bus_poll (bus, GST_MESSAGE_ANY, GST_SECOND / 10);
+    if (message) {
+      switch (GST_MESSAGE_TYPE (message)) {
+        case GST_MESSAGE_EOS:
+        {
+          /* we should check if we really finished here */
+          GST_WARNING ("Got an EOS");
+          carry_on = FALSE;
+          break;
+        }
+        case GST_MESSAGE_STATE_CHANGED:
+        {
+          GstState new;
+
+          if (GST_MESSAGE_SRC (message) == GST_OBJECT (pipeline)) {
+            gst_message_parse_state_changed (message, NULL, &new, NULL);
+
+            if (new != GST_STATE_PLAYING)
+              break;
+
+            GST_INFO ("Seeking (num: %i)", count);
+            seek_res =
+                gst_element_seek_simple (sink, GST_FORMAT_BYTES,
+                GST_SEEK_FLAG_FLUSH | GST_SEEK_FLAG_ACCURATE, 0);
+            GST_INFO ("seek result is : %d", seek_res);
+            fail_unless (seek_res != 0);
+            count++;
+          }
+
+          break;
+        }
+        case GST_MESSAGE_ERROR:
+          GST_ERROR ("Error on the bus: %" GST_PTR_FORMAT, message);
+          carry_on = FALSE;
+          fail_error_message (message);
+          break;
+        default:
+          break;
+      }
+      gst_message_unref (message);
+    }
+  }
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (bus);
+  gst_object_unref (pipeline);
+}
+
+GST_START_TEST (test_infinite_seek)
+{
+  infinite_seek (2, 500);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_infinite_seek_50_src)
+{
+  infinite_seek (50, 100);
+}
+
+GST_END_TEST;
+
+typedef struct
+{
+  GstElement *agg, *src, *pipeline;
+  GCond *cond;
+  GMutex *lock;
+} RemoveElementData;
+
+static GstPadProbeReturn
+pad_probe_cb (GstPad * pad, GstPadProbeInfo * info, RemoveElementData * data)
+{
+  GstPad *peer;
+
+  GST_INFO_OBJECT (pad, "Removing pad");
+
+  peer = gst_pad_get_peer (pad);
+  gst_pad_unlink (pad, peer);
+  gst_element_release_request_pad (data->agg, peer);
+  fail_unless (gst_bin_remove (GST_BIN (data->pipeline), data->src));
+
+  g_mutex_lock (data->lock);
+  g_cond_broadcast (data->cond);
+  g_mutex_unlock (data->lock);
+
+  return GST_PAD_PROBE_OK;
+}
+
+GST_START_TEST (test_add_remove)
+{
+  /* Used to notify that we removed the pad from  */
+  GCond cond;
+  GMutex lock;
+
+  GstBus *bus;
+  GstState state;
+  GstMessage *message;
+  gboolean carry_on = TRUE;
+  guint num_iterations = 100;
+
+  GstPad *pad;
+  GstElement *pipeline, *src, *src1 = NULL, *agg, *sink;
+
+  gint count = 0;
+
+  gst_init (NULL, NULL);
+  g_mutex_init (&lock);
+  g_cond_init (&cond);
+
+  pipeline = gst_pipeline_new ("pipeline");
+
+  agg = gst_check_setup_element ("testaggregator");
+  sink = gst_check_setup_element ("fakesink");
+
+  fail_unless (gst_bin_add (GST_BIN (pipeline), agg));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), sink));
+  fail_unless (gst_element_link (agg, sink));
+
+  bus = gst_element_get_bus (pipeline);
+  while (count < num_iterations) {
+
+    src = gst_element_factory_make ("fakesrc", NULL);
+    g_object_set (src, "num-buffers", 100000, "sizetype", 2, "sizemax", 4,
+        NULL);
+    gst_element_set_locked_state (src, TRUE);
+    fail_unless (gst_bin_add (GST_BIN (pipeline), src));
+    fail_unless (gst_element_link (src, agg));
+    gst_element_set_locked_state (src, FALSE);
+    fail_unless (gst_element_sync_state_with_parent (src));
+
+    if (count == 0)
+      gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+    /* Now make sure the seek happend */
+    carry_on = TRUE;
+    do {
+      message = gst_bus_timed_pop (bus, -1);
+      switch (GST_MESSAGE_TYPE (message)) {
+        case GST_MESSAGE_EOS:
+        {
+          /* we should check if we really finished here */
+          GST_WARNING ("Got an EOS");
+          carry_on = FALSE;
+          break;
+        }
+        case GST_MESSAGE_STATE_CHANGED:
+        {
+          if (GST_MESSAGE_SRC (message) == GST_OBJECT (pipeline)) {
+            gst_message_parse_state_changed (message, NULL, &state, NULL);
+
+            if (state == GST_STATE_PLAYING) {
+              RemoveElementData data;
+
+              carry_on = FALSE;
+              if (count == 0) {
+                GST_DEBUG ("First run, not removing any element yet");
+
+                break;
+              }
+
+              data.src = gst_object_ref (src1);
+              data.agg = agg;
+              data.lock = &lock;
+              data.cond = &cond;
+              data.pipeline = pipeline;
+              pad = gst_element_get_static_pad (data.src, "src");
+
+              g_mutex_lock (&lock);
+              gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM,
+                  (GstPadProbeCallback) pad_probe_cb, &data, NULL);
+              GST_INFO ("Waiting for %" GST_PTR_FORMAT " %s", pad,
+                  gst_element_state_get_name (GST_STATE (data.src)));
+              g_cond_wait (&cond, &lock);
+              g_mutex_unlock (&lock);
+
+              /*  We can not set state from the streaming thread so we
+               *  need to make sure that the source has been removed
+               *  before setting its state to NULL */
+              gst_element_set_state (data.src, GST_STATE_NULL);
+
+              gst_object_unref (data.src);
+            }
+          }
+
+          break;
+        }
+        case GST_MESSAGE_ERROR:
+        {
+          GST_ERROR ("Error on the bus: %" GST_PTR_FORMAT, message);
+          carry_on = FALSE;
+          fail_error_message (message);
+          break;
+        }
+        default:
+          break;
+      }
+
+      gst_message_unref (message);
+    } while (carry_on);
+
+    GST_INFO ("Seeking");
+    fail_unless (gst_element_seek_simple (pipeline, GST_FORMAT_BYTES,
+            GST_SEEK_FLAG_FLUSH | GST_SEEK_FLAG_ACCURATE, 0));
+
+    count++;
+    src1 = src;
+  }
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (bus);
+  gst_object_unref (pipeline);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_change_state_intensive)
+{
+  GstBus *bus;
+  GstMessage *message;
+  GstElement *pipeline, *src, *agg, *sink;
+
+  gint i, state_i = 0, num_srcs = 3;
+  gboolean carry_on = TRUE, ready = FALSE;
+  GstStateChangeReturn state_return;
+  GstState wanted_state, wanted_states[] = {
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PAUSED, GST_STATE_READY,
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PAUSED, GST_STATE_READY,
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PAUSED, GST_STATE_READY,
+    GST_STATE_PAUSED, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_READY,
+    GST_STATE_PAUSED, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_NULL,
+    GST_STATE_PAUSED, GST_STATE_NULL, GST_STATE_PAUSED, GST_STATE_NULL,
+    GST_STATE_PAUSED, GST_STATE_NULL, GST_STATE_PAUSED, GST_STATE_NULL,
+    GST_STATE_PAUSED, GST_STATE_NULL, GST_STATE_PLAYING, GST_STATE_NULL,
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PLAYING, GST_STATE_NULL,
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PLAYING, GST_STATE_NULL,
+    GST_STATE_PLAYING, GST_STATE_NULL, GST_STATE_PLAYING, GST_STATE_NULL,
+  };
+
+  gst_init (NULL, NULL);
+
+  pipeline = gst_pipeline_new ("pipeline");
+
+  agg = gst_check_setup_element ("testaggregator");
+  sink = gst_check_setup_element ("fakesink");
+
+  fail_unless (gst_bin_add (GST_BIN (pipeline), agg));
+  fail_unless (gst_bin_add (GST_BIN (pipeline), sink));
+  fail_unless (gst_element_link (agg, sink));
+
+  for (i = 0; i < num_srcs; i++) {
+    src = gst_element_factory_make ("fakesrc", NULL);
+    g_object_set (src, "sizetype", 2, "sizemax", 4, NULL);
+    fail_unless (gst_bin_add (GST_BIN (pipeline), src));
+    fail_unless (gst_element_link (src, agg));
+  }
+
+  bus = gst_element_get_bus (pipeline);
+  fail_if (bus == NULL);
+
+  wanted_state = wanted_states[state_i++];
+  state_return = gst_element_set_state (pipeline, wanted_state);
+
+  while (state_i < G_N_ELEMENTS (wanted_states) && carry_on) {
+    if (state_return == GST_STATE_CHANGE_SUCCESS && ready) {
+      wanted_state = wanted_states[state_i++];
+      fail_unless (gst_element_set_state (pipeline, wanted_state),
+          GST_STATE_CHANGE_SUCCESS);
+      GST_INFO ("Wanted state: %s", gst_element_state_get_name (wanted_state));
+    }
+
+    message = gst_bus_poll (bus, GST_MESSAGE_ANY, GST_SECOND / 10);
+    if (message) {
+      switch (GST_MESSAGE_TYPE (message)) {
+        case GST_MESSAGE_EOS:
+        {
+          /* we should check if we really finished here */
+          GST_WARNING ("Got an EOS");
+          carry_on = FALSE;
+          break;
+        }
+        case GST_MESSAGE_STATE_CHANGED:
+        {
+          GstState new;
+
+          if (GST_MESSAGE_SRC (message) == GST_OBJECT (pipeline)) {
+            gst_message_parse_state_changed (message, NULL, &new, NULL);
+
+            if (new != wanted_state) {
+              ready = FALSE;
+              break;
+            }
+
+            GST_DEBUG ("State %s reached",
+                gst_element_state_get_name (wanted_state));
+            wanted_state = wanted_states[state_i++];
+            GST_DEBUG ("Wanted state: %s",
+                gst_element_state_get_name (wanted_state));
+            state_return = gst_element_set_state (pipeline, wanted_state);
+            fail_unless (state_return == GST_STATE_CHANGE_SUCCESS ||
+                state_return == GST_STATE_CHANGE_ASYNC);
+            ready = TRUE;
+          }
+
+          break;
+        }
+        case GST_MESSAGE_ERROR:
+          GST_ERROR ("Error on the bus: %" GST_PTR_FORMAT, message);
+          carry_on = FALSE;
+          break;
+        default:
+          break;
+      }
+      gst_message_unref (message);
+    }
+  }
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (bus);
+  gst_object_unref (pipeline);
+}
+
+GST_END_TEST;
+
+static Suite *
+gst_aggregator_suite (void)
+{
+  Suite *suite;
+  TCase *general;
+
+  gst_test_aggregator_plugin_register ();
+
+  suite = suite_create ("GstAggregator");
+
+  general = tcase_create ("general");
+  suite_add_tcase (suite, general);
+  tcase_add_test (general, test_aggregate);
+  tcase_add_test (general, test_aggregate_eos);
+  tcase_add_test (general, test_flushing_seek);
+  tcase_add_test (general, test_infinite_seek);
+  tcase_add_test (general, test_infinite_seek_50_src);
+  tcase_add_test (general, test_linear_pipeline);
+  tcase_add_test (general, test_two_src_pipeline);
+  tcase_add_test (general, test_add_remove);
+  tcase_add_test (general, test_change_state_intensive);
+
+  return suite;
+}
+
+GST_CHECK_MAIN (gst_aggregator);