[MOVED FROM GST-P-FARSIGHT] Add liveadder element

20080329004518-3e2dc-40e4746fe82bbc5a871f03fe6ff6048f436c9f85.gz

4 files changed, 1340 insertions, 0 deletions

diff --git a/gst/liveadder/.git-darcs-dir b/gst/liveadder/.git-darcs-dir
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/gst/liveadder/.git-darcs-dir
diff --git a/gst/liveadder/Makefile.am b/gst/liveadder/Makefile.am
new file mode 100644
index 000000000..3db27f485
--- /dev/null
+++ b/gst/liveadder/Makefile.am
@@ -0,0 +1,8 @@
+plugin_LTLIBRARIES = libgstliveadder.la
+
+libgstliveadder_la_SOURCES = liveadder.c
+libgstliveadder_la_CFLAGS = $(GST_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(ERROR_CFLAGS)
+libgstliveadder_la_LIBADD = $(GST_LIBS_LIBS)
+libgstliveadder_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS) $(GST_BASE_LIBS) $(GST_PLUGINS_BASE_LIBS) -lgstaudio-0.10
+
+noinst_HEADERS = liveadder.h
diff --git a/gst/liveadder/liveadder.c b/gst/liveadder/liveadder.c
new file mode 100644
index 000000000..861518d4c
--- /dev/null
+++ b/gst/liveadder/liveadder.c
@@ -0,0 +1,1228 @@
+/*
+ * Farsight Voice+Video library
+ *
+ *  Copyright 2008 Collabora Ltd
+ *  Copyright 2008 Nokia Corporation
+ *   @author: Olivier Crete <olivier.crete@collabora.co.uk>
+ *
+ * With parts copied from the adder plugin which is
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2001 Thomas <thomas@apestaart.org>
+ *               2005,2006 Wim Taymans <wim@fluendo.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "liveadder.h"
+
+#include <gst/audio/audio.h>
+
+#include <string.h>
+
+#define DEFAULT_LATENCY_MS 60
+
+GST_DEBUG_CATEGORY_STATIC (live_adder_debug);
+#define GST_CAT_DEFAULT (live_adder_debug)
+
+/* elementfactory information */
+static const GstElementDetails gst_live_adder_details =
+GST_ELEMENT_DETAILS (
+  "Live Adder element",
+  "Generic/Audio",
+  "Mixes live/discontinuous audio streams",
+  "Olivier Crete <olivier.crete@collabora.co.uk>");
+
+
+static GstStaticPadTemplate gst_live_adder_sink_template =
+    GST_STATIC_PAD_TEMPLATE ("sink%d",
+        GST_PAD_SINK,
+        GST_PAD_REQUEST,
+        GST_STATIC_CAPS (GST_AUDIO_INT_PAD_TEMPLATE_CAPS "; "
+            GST_AUDIO_FLOAT_PAD_TEMPLATE_CAPS)
+        );
+
+static GstStaticPadTemplate gst_live_adder_src_template =
+    GST_STATIC_PAD_TEMPLATE ("src",
+        GST_PAD_SRC,
+        GST_PAD_ALWAYS,
+        GST_STATIC_CAPS (GST_AUDIO_INT_PAD_TEMPLATE_CAPS "; "
+            GST_AUDIO_FLOAT_PAD_TEMPLATE_CAPS)
+        );
+
+/* Valve signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+enum
+{
+  PROP_0,
+  PROP_LATENCY,
+};
+
+typedef struct _GstLiveAdderPadPrivate
+{
+  GstSegment segment;
+  gboolean eos;
+
+  GstClockTime next_timestamp;
+
+} GstLiveAdderPadPrivate;
+
+
+GST_BOILERPLATE(GstLiveAdder, gst_live_adder, GstElement, GST_TYPE_ELEMENT);
+
+
+static void
+gst_live_adder_finalize (GObject * object);
+static void
+gst_live_adder_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec);
+static void
+gst_live_adder_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec);
+
+static GstPad *
+gst_live_adder_request_new_pad (GstElement * element, GstPadTemplate * templ,
+    const gchar * unused);
+static void
+gst_live_adder_release_pad (GstElement * element, GstPad * pad);
+static GstStateChangeReturn
+gst_live_adder_change_state (GstElement * element, GstStateChange transition);
+
+static gboolean
+gst_live_adder_setcaps (GstPad * pad, GstCaps * caps);
+static GstCaps *
+gst_live_adder_sink_getcaps (GstPad * pad);
+static gboolean
+gst_live_adder_src_activate_push (GstPad * pad, gboolean active);
+
+static void
+gst_live_adder_loop (gpointer data);
+static gboolean
+gst_live_adder_query (GstPad * pad, GstQuery * query);
+static gboolean
+gst_live_adder_sink_event (GstPad * pad, GstEvent * event);
+
+
+/* highest positive/lowest negative x-bit value we can use for clamping */
+#define MAX_INT_32  ((gint32) (0x7fffffff))
+#define MAX_INT_16  ((gint16) (0x7fff))
+#define MAX_INT_8   ((gint8)  (0x7f))
+#define MAX_UINT_32 ((guint32)(0xffffffff))
+#define MAX_UINT_16 ((guint16)(0xffff))
+#define MAX_UINT_8  ((guint8) (0xff))
+
+#define MIN_INT_32  ((gint32) (0x80000000))
+#define MIN_INT_16  ((gint16) (0x8000))
+#define MIN_INT_8   ((gint8)  (0x80))
+#define MIN_UINT_32 ((guint32)(0x00000000))
+#define MIN_UINT_16 ((guint16)(0x0000))
+#define MIN_UINT_8  ((guint8) (0x00))
+
+/* clipping versions */
+#define MAKE_FUNC(name,type,ttype,min,max)                      \
+static void name (type *out, type *in, gint bytes) {            \
+  gint i;                                                       \
+  for (i = 0; i < bytes / sizeof (type); i++)                   \
+    out[i] = CLAMP ((ttype)out[i] + (ttype)in[i], min, max);    \
+}
+
+/* non-clipping versions (for float) */
+#define MAKE_FUNC_NC(name,type,ttype)                           \
+static void name (type *out, type *in, gint bytes) {            \
+  gint i;                                                       \
+  for (i = 0; i < bytes / sizeof (type); i++)                   \
+    out[i] = (ttype)out[i] + (ttype)in[i];                      \
+}
+
+/* *INDENT-OFF* */
+MAKE_FUNC (add_int32, gint32, gint64, MIN_INT_32, MAX_INT_32)
+MAKE_FUNC (add_int16, gint16, gint32, MIN_INT_16, MAX_INT_16)
+MAKE_FUNC (add_int8, gint8, gint16, MIN_INT_8, MAX_INT_8)
+MAKE_FUNC (add_uint32, guint32, guint64, MIN_UINT_32, MAX_UINT_32)
+MAKE_FUNC (add_uint16, guint16, guint32, MIN_UINT_16, MAX_UINT_16)
+MAKE_FUNC (add_uint8, guint8, guint16, MIN_UINT_8, MAX_UINT_8)
+MAKE_FUNC_NC (add_float64, gdouble, gdouble)
+MAKE_FUNC_NC (add_float32, gfloat, gfloat)
+/* *INDENT-ON* */
+
+
+static void
+gst_live_adder_base_init (gpointer klass)
+{
+}
+
+static void
+gst_live_adder_class_init (GstLiveAdderClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  gobject_class->finalize = gst_live_adder_finalize;
+  gobject_class->set_property = gst_live_adder_set_property;
+  gobject_class->get_property = gst_live_adder_get_property;
+
+  gstelement_class = (GstElementClass *) klass;
+
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&gst_live_adder_src_template));
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&gst_live_adder_sink_template));
+  gst_element_class_set_details (gstelement_class, &gst_live_adder_details);
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gstelement_class->request_new_pad = gst_live_adder_request_new_pad;
+  gstelement_class->release_pad = gst_live_adder_release_pad;
+  gstelement_class->change_state = gst_live_adder_change_state;
+
+  g_object_class_install_property (gobject_class, PROP_LATENCY,
+      g_param_spec_uint ("latency", "Buffer latency in ms",
+          "Amount of data to buffer", 0, G_MAXUINT, DEFAULT_LATENCY_MS,
+          G_PARAM_READWRITE));
+
+  GST_DEBUG_CATEGORY_INIT
+      (live_adder_debug, "liveadder", 0, "Live Adder");
+
+}
+
+static void
+gst_live_adder_init (GstLiveAdder * adder, GstLiveAdderClass *klass)
+{
+  GstPadTemplate *template;
+
+  template = gst_static_pad_template_get (&gst_live_adder_src_template);
+  adder->srcpad = gst_pad_new_from_template (template, "src");
+  gst_object_unref (template);
+  gst_pad_set_getcaps_function (adder->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));
+  gst_pad_set_setcaps_function (adder->srcpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_setcaps));
+  gst_pad_set_query_function (adder->srcpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_query));
+  gst_pad_set_activatepush_function (adder->srcpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_src_activate_push));
+  gst_element_add_pad (GST_ELEMENT (adder), adder->srcpad);
+
+  adder->format = GST_LIVE_ADDER_FORMAT_UNSET;
+  adder->padcount = 0;
+  adder->func = NULL;
+  adder->not_empty_cond = g_cond_new ();
+
+  adder->next_timestamp = GST_CLOCK_TIME_NONE;
+
+  adder->latency_ms = DEFAULT_LATENCY_MS;
+
+  adder->buffers = g_queue_new ();
+}
+
+
+
+static void
+gst_live_adder_finalize (GObject * object)
+{
+  GstLiveAdder *adder = GST_LIVE_ADDER (object);
+
+  g_cond_free (adder->not_empty_cond);
+
+  g_queue_foreach (adder->buffers, (GFunc) gst_mini_object_unref, NULL);
+  g_queue_clear (adder->buffers);
+  g_queue_free (adder->buffers);
+
+  g_list_free (adder->sinkpads);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+
+static void
+gst_live_adder_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec)
+{
+  GstLiveAdder *adder = GST_LIVE_ADDER (object);
+
+  switch (prop_id) {
+    case PROP_LATENCY:
+    {
+      guint64 new_latency, old_latency;
+
+      new_latency = g_value_get_uint (value);
+
+      GST_OBJECT_LOCK (adder);
+      old_latency = adder->latency_ms;
+      adder->latency_ms = new_latency;
+      GST_OBJECT_UNLOCK (adder);
+
+      /* post message if latency changed, this will inform the parent pipeline
+       * that a latency reconfiguration is possible/needed. */
+      if (new_latency != old_latency) {
+        GST_DEBUG_OBJECT (adder, "latency changed to: %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (new_latency));
+
+        gst_element_post_message (GST_ELEMENT_CAST (adder),
+            gst_message_new_latency (GST_OBJECT_CAST (adder)));
+      }
+      break;
+    }
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+
+static void
+gst_live_adder_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec)
+{
+  GstLiveAdder *adder = GST_LIVE_ADDER (object);
+
+  switch (prop_id) {
+    case PROP_LATENCY:
+      GST_OBJECT_LOCK (adder);
+      g_value_set_uint (value, adder->latency_ms);
+      GST_OBJECT_UNLOCK (adder);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+
+/* we can only accept caps that we and downstream can handle. */
+static GstCaps *
+gst_live_adder_sink_getcaps (GstPad * pad)
+{
+  GstLiveAdder *adder;
+  GstCaps *result, *peercaps, *sinkcaps;
+
+  adder = GST_LIVE_ADDER (GST_PAD_PARENT (pad));
+
+  GST_OBJECT_LOCK (adder);
+  /* get the downstream possible caps */
+  peercaps = gst_pad_peer_get_caps (adder->srcpad);
+  /* get the allowed caps on this sinkpad, we use the fixed caps function so
+   * that it does not call recursively in this function. */
+  sinkcaps = gst_pad_get_fixed_caps_func (pad);
+  if (peercaps) {
+    /* if the peer has caps, intersect */
+    GST_DEBUG_OBJECT (adder, "intersecting peer and template caps");
+    result = gst_caps_intersect (peercaps, sinkcaps);
+    gst_caps_unref (peercaps);
+    gst_caps_unref (sinkcaps);
+  } else {
+    /* the peer has no caps (or there is no peer), just use the allowed caps
+     * of this sinkpad. */
+    GST_DEBUG_OBJECT (adder, "no peer caps, using sinkcaps");
+    result = sinkcaps;
+  }
+  GST_OBJECT_UNLOCK (adder);
+
+  return result;
+}
+
+/* the first caps we receive on any of the sinkpads will define the caps for all
+ * the other sinkpads because we can only mix streams with the same caps.
+ * */
+static gboolean
+gst_live_adder_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstLiveAdder *adder;
+  GList *pads;
+  GstStructure *structure;
+  const char *media_type;
+
+  adder = GST_LIVE_ADDER (GST_PAD_PARENT (pad));
+
+  GST_LOG_OBJECT (adder, "setting caps on pad %p,%s to %" GST_PTR_FORMAT, pad,
+      GST_PAD_NAME (pad), caps);
+
+  /* FIXME, see if the other pads can accept the format. Also lock the
+   * format on the other pads to this new format. */
+  GST_OBJECT_LOCK (adder);
+  pads = GST_ELEMENT (adder)->pads;
+  while (pads) {
+    GstPad *otherpad = GST_PAD (pads->data);
+
+    if (otherpad != pad) {
+      gst_caps_replace (&GST_PAD_CAPS (otherpad), caps);
+    }
+    gst_pad_use_fixed_caps (pad);
+
+    pads = g_list_next (pads);
+  }
+  GST_OBJECT_UNLOCK (adder);
+
+  /* parse caps now */
+  structure = gst_caps_get_structure (caps, 0);
+  media_type = gst_structure_get_name (structure);
+  if (strcmp (media_type, "audio/x-raw-int") == 0) {
+    GST_DEBUG_OBJECT (adder, "parse_caps sets adder to format int");
+    adder->format = GST_LIVE_ADDER_FORMAT_INT;
+    gst_structure_get_int (structure, "width", &adder->width);
+    gst_structure_get_int (structure, "depth", &adder->depth);
+    gst_structure_get_int (structure, "endianness", &adder->endianness);
+    gst_structure_get_boolean (structure, "signed", &adder->is_signed);
+
+    if (adder->endianness != G_BYTE_ORDER)
+      goto not_supported;
+
+    switch (adder->width) {
+      case 8:
+        adder->func = (adder->is_signed ?
+            (GstLiveAdderFunction) add_int8 : (GstLiveAdderFunction) add_uint8);
+        break;
+      case 16:
+        adder->func = (adder->is_signed ?
+            (GstLiveAdderFunction) add_int16 : (GstLiveAdderFunction) add_uint16);
+        break;
+      case 32:
+        adder->func = (adder->is_signed ?
+            (GstLiveAdderFunction) add_int32 : (GstLiveAdderFunction) add_uint32);
+        break;
+      default:
+        goto not_supported;
+    }
+  } else if (strcmp (media_type, "audio/x-raw-float") == 0) {
+    GST_DEBUG_OBJECT (adder, "parse_caps sets adder to format float");
+    adder->format = GST_LIVE_ADDER_FORMAT_FLOAT;
+    gst_structure_get_int (structure, "width", &adder->width);
+
+    switch (adder->width) {
+      case 32:
+        adder->func = (GstLiveAdderFunction) add_float32;
+        break;
+      case 64:
+        adder->func = (GstLiveAdderFunction) add_float64;
+        break;
+      default:
+        goto not_supported;
+    }
+  } else {
+    goto not_supported;
+  }
+
+  gst_structure_get_int (structure, "channels", &adder->channels);
+  gst_structure_get_int (structure, "rate", &adder->rate);
+  /* precalc bps */
+  adder->bps = (adder->width / 8) * adder->channels;
+
+  return TRUE;
+
+  /* ERRORS */
+not_supported:
+  {
+    GST_DEBUG_OBJECT (adder, "unsupported format set as caps");
+    return FALSE;
+  }
+}
+
+static void
+gst_live_adder_flush_start (GstLiveAdder * adder)
+{
+  GST_OBJECT_LOCK (adder);
+  /* mark ourselves as flushing */
+  adder->srcresult = GST_FLOW_WRONG_STATE;
+  GST_DEBUG_OBJECT (adder, "Disabling pop on queue");
+  /* unlock clock, we just unschedule, the entry will be released by the
+   * locking streaming thread. */
+  if (adder->clock_id)
+    gst_clock_id_unschedule (adder->clock_id);
+  GST_OBJECT_UNLOCK (adder);
+}
+
+static void
+gst_live_adder_flush_stop (GstLiveAdder * adder)
+{
+  GST_OBJECT_LOCK (adder);
+  GST_DEBUG_OBJECT (adder, "Enabling pop on queue");
+  /* Mark as non flushing */
+  adder->srcresult = GST_FLOW_OK;
+  GST_OBJECT_UNLOCK (adder);
+}
+
+static gboolean
+gst_live_adder_src_activate_push (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstLiveAdder *adder = NULL;
+
+  adder = GST_LIVE_ADDER (gst_pad_get_parent (pad));
+
+  if (active) {
+    /* allow data processing */
+    gst_live_adder_flush_stop (adder);
+
+    /* start pushing out buffers */
+    GST_DEBUG_OBJECT (adder, "Starting task on srcpad");
+    gst_pad_start_task (adder->srcpad,
+        (GstTaskFunction) gst_live_adder_loop, adder);
+  } else {
+    /* make sure all data processing stops ASAP */
+    gst_live_adder_flush_start (adder);
+
+    /* NOTE this will hardlock if the state change is called from the src pad
+     * task thread because we will _join() the thread. */
+    GST_DEBUG_OBJECT (adder, "Stopping task on srcpad");
+    result = gst_pad_stop_task (pad);
+  }
+
+  gst_object_unref (adder);
+
+  return result;
+}
+
+static gboolean
+gst_live_adder_sink_event (GstPad * pad, GstEvent * event)
+{
+  gboolean ret = TRUE;
+  GstLiveAdder *adder = NULL;
+  GstLiveAdderPadPrivate *padprivate = NULL;
+
+  adder = GST_LIVE_ADDER (gst_pad_get_parent (pad));
+
+  padprivate = gst_pad_get_element_private (pad);
+
+  if (!padprivate)
+    return FALSE;
+
+  GST_LOG_OBJECT (adder, "received %s", GST_EVENT_TYPE_NAME (event));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_NEWSEGMENT:
+    {
+      GstFormat format;
+      gdouble rate, arate;
+      gint64 start, stop, time;
+      gboolean update;
+
+      gst_event_parse_new_segment_full (event, &update, &rate, &arate, &format,
+          &start, &stop, &time);
+
+      /* we need time for now */
+      if (format != GST_FORMAT_TIME)
+        goto newseg_wrong_format;
+
+      GST_DEBUG_OBJECT (adder,
+          "newsegment: update %d, rate %g, arate %g, start %" GST_TIME_FORMAT
+          ", stop %" GST_TIME_FORMAT ", time %" GST_TIME_FORMAT,
+          update, rate, arate, GST_TIME_ARGS (start), GST_TIME_ARGS (stop),
+          GST_TIME_ARGS (time));
+
+      /* now configure the values, we need these to time the release of the
+       * buffers on the srcpad. */
+      GST_OBJECT_LOCK (adder);
+      gst_segment_set_newsegment_full (&padprivate->segment, update,
+          rate, arate, format, start, stop, time);
+      GST_OBJECT_UNLOCK (adder);
+
+      gst_event_unref (event);
+      break;
+    }
+    case GST_EVENT_FLUSH_START:
+      gst_live_adder_flush_start (adder);
+      ret = gst_pad_push_event (adder->srcpad, event);
+      break;
+    case GST_EVENT_FLUSH_STOP:
+      ret = gst_pad_push_event (adder->srcpad, event);
+      ret = gst_live_adder_src_activate_push (adder->srcpad, TRUE);
+      break;
+    case GST_EVENT_EOS:
+    {
+      GST_OBJECT_LOCK (adder);
+
+      ret = adder->srcresult == GST_FLOW_OK;
+      if (ret && !padprivate->eos) {
+        GST_DEBUG_OBJECT (adder, "queuing EOS");
+        padprivate->eos = TRUE;
+        g_cond_signal (adder->not_empty_cond);
+      } else if (padprivate->eos) {
+        GST_DEBUG_OBJECT (adder, "dropping EOS, we are already EOS");
+      } else {
+        GST_DEBUG_OBJECT (adder, "dropping EOS, reason %s",
+            gst_flow_get_name (adder->srcresult));
+      }
+
+      GST_OBJECT_UNLOCK (adder);
+
+      gst_event_unref (event);
+      break;
+    }
+    default:
+      ret = gst_pad_push_event (adder->srcpad, event);
+      break;
+  }
+
+done:
+  gst_object_unref (adder);
+
+  return ret;
+
+  /* ERRORS */
+newseg_wrong_format:
+  {
+    GST_DEBUG_OBJECT (adder, "received non TIME newsegment");
+    ret = FALSE;
+    goto done;
+  }
+}
+
+static gboolean
+gst_live_adder_query (GstPad * pad, GstQuery * query)
+{
+  GstLiveAdder *adder;
+  gboolean res = FALSE;
+
+  adder = GST_LIVE_ADDER (gst_pad_get_parent (pad));
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_LATENCY:
+    {
+      /* We need to send the query upstream and add the returned latency to our
+       * own */
+      GstClockTime min_latency = G_MAXUINT64, max_latency = 0;
+      gpointer item;
+      GstIterator *iter = NULL;
+      gboolean done = FALSE;
+
+      iter = gst_element_iterate_sink_pads (GST_ELEMENT (adder));
+
+      while (!done) {
+        switch (gst_iterator_next (iter, &item)) {
+          case GST_ITERATOR_OK:
+            {
+              GstPad *sinkpad = item;
+              GstClockTime pad_min_latency, pad_max_latency;
+              gboolean pad_us_live;
+
+              if (gst_pad_peer_query (sinkpad, query)) {
+                gst_query_parse_latency (query, &pad_us_live, &pad_min_latency,
+                    &pad_max_latency);
+
+                res = TRUE;
+
+                GST_DEBUG_OBJECT (adder, "Peer latency for pad %s: min %"
+                    GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
+                    GST_PAD_NAME (sinkpad),
+                    GST_TIME_ARGS (pad_min_latency), GST_TIME_ARGS (pad_max_latency));
+
+                min_latency = MIN (pad_min_latency, min_latency);
+                max_latency = MAX (pad_max_latency, max_latency);
+              }
+              gst_object_unref (item);
+            }
+            break;
+          case GST_ITERATOR_RESYNC:
+            min_latency = G_MAXUINT64;
+            max_latency = 0;
+
+            gst_iterator_resync (iter);
+            break;
+          case GST_ITERATOR_ERROR:
+            GST_ERROR_OBJECT (adder, "Error looping sink pads");
+            done = TRUE;
+            break;
+          case GST_ITERATOR_DONE:
+            done = TRUE;
+            break;
+        }
+      }
+      gst_iterator_free (iter);
+
+      if (res) {
+        if (min_latency == G_MAXUINT64)
+          min_latency = 0;
+
+        GST_OBJECT_LOCK (adder);
+        adder->peer_latency = min_latency;
+        min_latency += adder->latency_ms * GST_MSECOND;
+        GST_OBJECT_UNLOCK (adder);
+
+        max_latency = MAX (max_latency, min_latency);
+        gst_query_set_latency (query, TRUE, min_latency, max_latency);
+        GST_DEBUG_OBJECT (adder, "Calculated total latency : min %"
+            GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
+      }
+      break;
+    }
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+
+  gst_object_unref (adder);
+
+  return res;
+}
+
+static guint
+gst_live_adder_length_from_duration (GstLiveAdder *adder, GstClockTime duration)
+{
+  guint64 ret = (duration * adder->rate / GST_SECOND) * adder->bps;
+
+  return (guint) ret;
+}
+
+static GstFlowReturn
+gst_live_live_adder_chain (GstPad *pad, GstBuffer *buffer)
+{
+  GstLiveAdder *adder = GST_LIVE_ADDER (gst_pad_get_parent_element (pad));
+  GstLiveAdderPadPrivate *padprivate = NULL;
+  GstFlowReturn ret = GST_FLOW_OK;
+  GList *item = NULL;
+  GstClockTime skip = 0;
+
+  GST_OBJECT_LOCK (adder);
+
+  ret = adder->srcresult;
+
+  if (ret != GST_FLOW_OK)
+  {
+    gst_buffer_unref (buffer);
+    goto out;
+  }
+
+  padprivate = gst_pad_get_element_private (pad);
+
+  if (!padprivate)
+  {
+    ret = GST_FLOW_NOT_LINKED;
+    gst_buffer_unref (buffer);
+    goto out;
+  }
+
+  if (padprivate->eos)
+  {
+    GST_DEBUG_OBJECT (adder, "Received buffer after EOS");
+    ret = GST_FLOW_UNEXPECTED;
+    gst_buffer_unref (buffer);
+    goto out;
+  }
+
+  if (!GST_BUFFER_TIMESTAMP_IS_VALID(buffer)) {
+    GST_ELEMENT_ERROR (adder, STREAM, FAILED,
+        ("Buffer without a valid timestamp received"), (""));
+    ret = GST_FLOW_ERROR;
+    gst_buffer_unref (buffer);
+    goto out;
+  }
+
+  /* Just see if we receive invalid timestamp/durations */
+  if (GST_CLOCK_TIME_IS_VALID (padprivate->next_timestamp) &&
+      !GST_BUFFER_FLAG_IS_SET(buffer, GST_BUFFER_FLAG_DISCONT) &&
+      GST_BUFFER_TIMESTAMP(buffer) != padprivate->next_timestamp)
+    GST_ERROR_OBJECT (adder,
+        "Timestamp discontinuity without the DISCONT flag set"
+        " (expected %" GST_TIME_FORMAT ", got %" GST_TIME_FORMAT")",
+        GST_TIME_ARGS (padprivate->next_timestamp),
+        GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));
+
+  padprivate->next_timestamp = GST_BUFFER_TIMESTAMP (buffer) +
+      GST_BUFFER_DURATION (buffer);
+
+  buffer = gst_buffer_make_metadata_writable (buffer);
+
+  /*
+   * Lets clip the buffer to the segment (so we don't have to worry about
+   * cliping afterwards).
+   * This should also guarantee us that we'll have valid timestamps and
+   * durations afterwards
+   */
+
+  buffer = gst_audio_buffer_clip (buffer, &padprivate->segment, adder->rate,
+      adder->bps);
+
+  /*
+   * Make sure all incoming buffers share the same timestamping
+   */
+  GST_BUFFER_TIMESTAMP (buffer) = gst_segment_to_running_time (
+      &padprivate->segment, padprivate->segment.format,
+      GST_BUFFER_TIMESTAMP (buffer));
+
+
+  if (GST_CLOCK_TIME_IS_VALID (adder->next_timestamp) &&
+      GST_BUFFER_TIMESTAMP (buffer) < adder->next_timestamp) {
+    if (GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer) <
+        adder->next_timestamp) {
+      GST_DEBUG_OBJECT (adder, "Buffer is late, dropping (ts: %" GST_TIME_FORMAT
+          " duration: %" GST_TIME_FORMAT ")",
+          GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
+          GST_TIME_ARGS (GST_BUFFER_DURATION (buffer)));
+      gst_buffer_unref (buffer);
+      goto out;
+    } else {
+      skip = adder->next_timestamp - GST_BUFFER_TIMESTAMP (buffer);
+      GST_DEBUG_OBJECT (adder, "Buffer is partially late, skipping %"
+          GST_TIME_FORMAT,
+          GST_TIME_ARGS (skip));
+    }
+  }
+
+  /* If our new buffer's head is higher than the queue's head, lets wake up,
+   * we may not have to wait for as long
+   */
+  if (adder->clock_id &&
+      GST_BUFFER_TIMESTAMP (buffer) + skip <
+      GST_BUFFER_TIMESTAMP (g_queue_peek_head (adder->buffers)))
+    gst_clock_id_unschedule (adder->clock_id);
+
+  for (item = g_queue_peek_head_link (adder->buffers);
+       item;
+       item = g_list_next (item)) {
+    GstBuffer *oldbuffer = item->data;
+    GstClockTime old_skip = 0;
+    GstClockTime mix_duration = 0;
+    GstClockTime mix_start = 0;
+    GstClockTime mix_end = 0;
+
+    /* We haven't reached our place yet */
+    if (GST_BUFFER_TIMESTAMP (buffer) + skip >=
+        GST_BUFFER_TIMESTAMP (oldbuffer) + GST_BUFFER_DURATION (oldbuffer))
+      continue;
+
+    /* We're past our place, lets insert ouselves here */
+    if (GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer) <=
+        GST_BUFFER_TIMESTAMP (oldbuffer))
+      break;
+
+    /* if we reach this spot, we have overlap, so we must mix */
+
+    /* First make a subbuffer with the non-overlapping part */
+    if (GST_BUFFER_TIMESTAMP (buffer) + skip <
+        GST_BUFFER_TIMESTAMP (oldbuffer)) {
+      GstBuffer *subbuffer = NULL;
+      GstClockTime subbuffer_duration = GST_BUFFER_TIMESTAMP (oldbuffer) -
+          (GST_BUFFER_TIMESTAMP (buffer) + skip);
+
+      subbuffer = gst_buffer_create_sub (buffer,
+          gst_live_adder_length_from_duration (adder, skip),
+          gst_live_adder_length_from_duration (adder, subbuffer_duration));
+
+      GST_BUFFER_TIMESTAMP (subbuffer) = GST_BUFFER_TIMESTAMP (buffer) + skip;
+      GST_BUFFER_DURATION (subbuffer) = subbuffer_duration;
+
+      skip += subbuffer_duration;
+
+      g_queue_insert_before (adder->buffers, item, subbuffer);
+    }
+
+    /* Now we are on the overlapping part */
+    oldbuffer = gst_buffer_make_writable (oldbuffer);
+    item->data = oldbuffer;
+
+    old_skip = GST_BUFFER_TIMESTAMP (buffer) + skip -
+        GST_BUFFER_TIMESTAMP (oldbuffer);
+
+    if (GST_BUFFER_TIMESTAMP (buffer) + skip >
+        GST_BUFFER_TIMESTAMP (oldbuffer) + old_skip)
+      mix_start = GST_BUFFER_TIMESTAMP (buffer) + skip;
+    else
+      mix_start = GST_BUFFER_TIMESTAMP (oldbuffer) + old_skip;
+
+    if (GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer) <
+        GST_BUFFER_TIMESTAMP (oldbuffer) + GST_BUFFER_DURATION (oldbuffer))
+      mix_end = GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer);
+    else
+      mix_end = GST_BUFFER_TIMESTAMP (oldbuffer) +
+          GST_BUFFER_DURATION (oldbuffer);
+
+    mix_duration = mix_end - mix_start;
+
+    adder->func (GST_BUFFER_DATA (oldbuffer) +
+        gst_live_adder_length_from_duration (adder, old_skip),
+        GST_BUFFER_DATA (buffer) +
+        gst_live_adder_length_from_duration (adder, skip),
+        gst_live_adder_length_from_duration (adder, mix_duration));
+
+    skip += mix_duration;
+  }
+
+  g_cond_signal (adder->not_empty_cond);
+
+  if (skip == GST_BUFFER_DURATION (buffer)) {
+    gst_buffer_unref (buffer);
+  } else {
+    if (skip) {
+      GstClockTime subbuffer_duration = GST_BUFFER_DURATION (buffer) - skip;
+      GstClockTime subbuffer_ts = GST_BUFFER_TIMESTAMP (buffer) + skip;
+
+      buffer = gst_buffer_create_sub (buffer,
+          gst_live_adder_length_from_duration (adder, skip),
+          gst_live_adder_length_from_duration (adder, subbuffer_duration));
+      GST_BUFFER_TIMESTAMP (buffer) = subbuffer_ts;
+      GST_BUFFER_DURATION (buffer) = subbuffer_duration;
+    }
+
+    if (item)
+      g_queue_insert_before (adder->buffers, item, buffer);
+    else
+      g_queue_push_tail (adder->buffers, buffer);
+  }
+
+ out:
+
+  GST_OBJECT_UNLOCK (adder);
+  gst_object_unref (adder);
+
+  return ret;
+}
+
+/*
+ * This only works because the GstObject lock is taken
+ *
+ * It checks if all sink pads are EOS
+ */
+static gboolean
+check_eos_locked (GstLiveAdder *adder)
+{
+  GList *item;
+
+  for (item = adder->sinkpads;
+       item;
+       item = g_list_next (item))
+  {
+    GstPad *pad = item->data;
+    GstLiveAdderPadPrivate *padprivate = gst_pad_get_element_private (pad);
+
+    if (padprivate && padprivate->eos != TRUE)
+      return FALSE;
+  }
+
+  return TRUE;
+}
+
+static void
+gst_live_adder_loop (gpointer data)
+{
+  GstLiveAdder *adder = GST_LIVE_ADDER (data);
+  GstClockTime buffer_timestamp = 0;
+  GstClockTime sync_time = 0;
+  GstClock *clock = NULL;
+  GstClockID id = NULL;
+  GstClockReturn ret;
+  GstBuffer *buffer = NULL;
+  GstFlowReturn result;
+
+  GST_OBJECT_LOCK (adder);
+
+ again:
+
+  for (;;)
+  {
+    if (!g_queue_is_empty (adder->buffers))
+      break;
+    if (check_eos_locked (adder))
+      goto eos;
+    g_cond_wait (adder->not_empty_cond, GST_OBJECT_GET_LOCK(adder));
+  }
+
+  buffer_timestamp = GST_BUFFER_TIMESTAMP (g_queue_peek_head (adder->buffers));
+
+  clock = GST_ELEMENT_CLOCK (adder);
+  if (!clock)
+    /* let's just push if there is no clock */
+    goto push_buffer;
+
+  GST_DEBUG_OBJECT (adder, "sync to timestamp %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (buffer_timestamp));
+
+  sync_time = buffer_timestamp + GST_ELEMENT_CAST (adder)->base_time;
+  /* add latency, this includes our own latency and the peer latency. */
+  sync_time += adder->latency_ms * GST_MSECOND;
+  sync_time += adder->peer_latency;
+
+  /* create an entry for the clock */
+  id = adder->clock_id = gst_clock_new_single_shot_id (clock, sync_time);
+  GST_OBJECT_UNLOCK (adder);
+
+  ret = gst_clock_id_wait (id, NULL);
+
+  GST_OBJECT_LOCK (adder);
+
+  /* and free the entry */
+  gst_clock_id_unref (id);
+  adder->clock_id = NULL;
+
+  /* at this point, the clock could have been unlocked by a timeout, a new
+   * head element was added to the queue or because we are shutting down. Check
+   * for shutdown first. */
+
+  if (adder->srcresult != GST_FLOW_OK)
+    goto flushing;
+
+  if (ret == GST_CLOCK_UNSCHEDULED) {
+    GST_DEBUG_OBJECT (adder,
+        "Wait got unscheduled, will retry to push with new buffer");
+    goto again;
+  }
+
+  if (ret != GST_CLOCK_OK && ret != GST_CLOCK_EARLY)
+    goto clock_error;
+
+ push_buffer:
+
+  buffer = g_queue_pop_head (adder->buffers);
+
+  if (!buffer)
+    goto again;
+
+  if (GST_CLOCK_TIME_IS_VALID (adder->next_timestamp) &&
+      GST_BUFFER_TIMESTAMP (buffer) != adder->next_timestamp)
+  {
+    if (llabs (GST_BUFFER_TIMESTAMP (buffer) - adder->next_timestamp) <
+        GST_SECOND / adder->rate) {
+      GST_BUFFER_TIMESTAMP (buffer) = adder->next_timestamp;
+      GST_DEBUG_OBJECT (adder, "Correcting slight skew");
+      GST_BUFFER_FLAG_UNSET(buffer, GST_BUFFER_FLAG_DISCONT);
+    } else {
+      GST_BUFFER_FLAG_SET(buffer, GST_BUFFER_FLAG_DISCONT);
+      GST_DEBUG_OBJECT (adder, "Expected buffer at %" GST_TIME_FORMAT
+          ", but is at %" GST_TIME_FORMAT", setting discont",
+          GST_TIME_ARGS (adder->next_timestamp),
+          GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));
+    }
+  } else {
+    GST_DEBUG_OBJECT (adder, "Continuous buffer");
+    GST_BUFFER_FLAG_UNSET(buffer, GST_BUFFER_FLAG_DISCONT);
+  }
+
+  adder->next_timestamp = GST_BUFFER_TIMESTAMP (buffer) +
+      GST_BUFFER_DURATION (buffer);
+
+  GST_OBJECT_UNLOCK (adder);
+
+  result = gst_pad_push (adder->srcpad, buffer);
+  if (result != GST_FLOW_OK)
+    goto pause;
+
+  return;
+
+ flushing:
+  {
+    GST_DEBUG_OBJECT (adder, "we are flushing");
+    gst_pad_pause_task (adder->srcpad);
+    GST_OBJECT_UNLOCK (adder);
+    return;
+  }
+
+ clock_error:
+ {
+   GST_ELEMENT_ERROR (adder, STREAM, MUX, ("Error with the clock"),
+       ("Error with the clock: %d", ret));
+   GST_ERROR_OBJECT (adder, "Error with the clock: %d", ret);
+   gst_pad_pause_task (adder->srcpad);
+   GST_OBJECT_UNLOCK (adder);
+   return;
+ }
+
+ pause:
+  {
+    const gchar *reason = gst_flow_get_name (result);
+
+    GST_DEBUG_OBJECT (adder, "pausing task, reason %s", reason);
+
+    GST_OBJECT_LOCK (adder);
+
+    /* store result */
+    adder->srcresult = result;
+    /* we don't post errors or anything because upstream will do that for us
+     * when we pass the return value upstream. */
+    gst_pad_pause_task (adder->srcpad);
+    GST_OBJECT_UNLOCK (adder);
+    return;
+  }
+
+ eos:
+  {
+    /* store result, we are flushing now */
+    GST_DEBUG_OBJECT (adder, "We are EOS, pushing EOS downstream");
+    adder->srcresult = GST_FLOW_UNEXPECTED;
+    gst_pad_pause_task (adder->srcpad);
+    gst_pad_push_event (adder->srcpad, gst_event_new_eos ());
+    GST_OBJECT_UNLOCK (adder);
+    return;
+  }
+}
+
+static GstPad *
+gst_live_adder_request_new_pad (GstElement * element, GstPadTemplate * templ,
+    const gchar * unused)
+{
+  gchar *name;
+  GstLiveAdder *adder;
+  GstPad *newpad;
+  gint padcount;
+  GstLiveAdderPadPrivate *padprivate = NULL;
+
+  if (templ->direction != GST_PAD_SINK)
+    goto not_sink;
+
+  adder = GST_LIVE_ADDER (element);
+
+  /* increment pad counter */
+  padcount = g_atomic_int_exchange_and_add (&adder->padcount, 1);
+
+  name = g_strdup_printf ("sink%d", padcount);
+  newpad = gst_pad_new_from_template (templ, name);
+  GST_DEBUG_OBJECT (adder, "request new pad %s", name);
+  g_free (name);
+
+  gst_pad_set_getcaps_function (newpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_sink_getcaps));
+  gst_pad_set_setcaps_function (newpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_setcaps));
+  gst_pad_set_event_function (newpad,
+      GST_DEBUG_FUNCPTR (gst_live_adder_sink_event));
+
+  padprivate = g_new0 (GstLiveAdderPadPrivate, 1);
+
+  gst_segment_init (&padprivate->segment, GST_FORMAT_UNDEFINED);
+  padprivate->eos = FALSE;
+  padprivate->next_timestamp = GST_CLOCK_TIME_NONE;
+
+  gst_pad_set_element_private (newpad, padprivate);
+
+  gst_pad_set_chain_function (newpad, gst_live_live_adder_chain);
+
+  /* takes ownership of the pad */
+  if (!gst_element_add_pad (GST_ELEMENT (adder), newpad))
+    goto could_not_add;
+
+  GST_OBJECT_LOCK (adder);
+  adder->sinkpads = g_list_prepend (adder->sinkpads, newpad);
+  GST_OBJECT_UNLOCK (adder);
+
+  return newpad;
+
+  /* errors */
+not_sink:
+  {
+    g_warning ("gstadder: request new pad that is not a SINK pad\n");
+    return NULL;
+  }
+could_not_add:
+  {
+    GST_DEBUG_OBJECT (adder, "could not add pad");
+    gst_object_unref (newpad);
+    return NULL;
+  }
+}
+
+static void
+gst_live_adder_release_pad (GstElement * element, GstPad * pad)
+{
+  GstLiveAdder *adder;
+  GstLiveAdderPadPrivate *padprivate;
+
+  adder = GST_LIVE_ADDER (element);
+
+  GST_DEBUG_OBJECT (adder, "release pad %s:%s", GST_DEBUG_PAD_NAME (pad));
+
+  GST_OBJECT_LOCK (element);
+  padprivate = gst_pad_get_element_private (pad);
+  gst_pad_set_element_private (pad, NULL);
+    adder->sinkpads = g_list_remove_all (adder->sinkpads, pad);
+  GST_OBJECT_UNLOCK (element);
+
+  g_free (padprivate);
+
+  gst_element_remove_pad (element, pad);
+}
+
+static void
+reset_pad_private (gpointer data, gpointer user_data)
+{
+  GstPad *pad = data;
+  //GstLiveAdder *adder = user_data;
+  GstLiveAdderPadPrivate *padprivate;
+
+  padprivate = gst_pad_get_element_private (pad);
+
+  if (!padprivate)
+    return;
+
+  gst_segment_init (&padprivate->segment, GST_FORMAT_UNDEFINED);
+
+  padprivate->next_timestamp = GST_CLOCK_TIME_NONE;
+  padprivate->eos = FALSE;
+}
+
+static GstStateChangeReturn
+gst_live_adder_change_state (GstElement * element, GstStateChange transition)
+{
+  GstLiveAdder *adder;
+  GstStateChangeReturn ret;
+
+  adder = GST_LIVE_ADDER (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      {
+        GST_OBJECT_LOCK (adder);
+        adder->peer_latency = 0;
+        adder->next_timestamp = GST_CLOCK_TIME_NONE;
+        g_list_foreach (adder->sinkpads, reset_pad_private, adder);
+        GST_OBJECT_UNLOCK (adder);
+        break;
+      }
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      break;
+    default:
+      break;
+  }
+
+  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+
+  switch (transition) {
+    default:
+      break;
+  }
+
+  return ret;
+}
+
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  if (!gst_element_register (plugin, "liveadder", GST_RANK_NONE,
+          GST_TYPE_LIVE_ADDER)) {
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "liveadder",
+    "Adds multiple live discontinuous streams",
+    plugin_init, VERSION, "LGPL", "Farsight", "http://farsight.sf.net")
diff --git a/gst/liveadder/liveadder.h b/gst/liveadder/liveadder.h
new file mode 100644
index 000000000..3cb368410
--- /dev/null
+++ b/gst/liveadder/liveadder.h
@@ -0,0 +1,104 @@
+/*
+ * Farsight Voice+Video library
+ *
+ *  Copyright 2008 Collabora Ltd
+ *  Copyright 2008 Nokia Corporation
+ *   @author: Olivier Crete <olivier.crete@collabora.co.uk>
+ *
+ * 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.
+ *
+ */
+
+
+
+#ifndef __GST_LIVE_ADDER_H__
+#define __GST_LIVE_ADDER_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_LIVE_ADDER            (gst_live_adder_get_type())
+#define GST_LIVE_ADDER(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LIVE_ADDER,GstLiveAdder))
+#define GST_IS_LIVE_ADDER(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LIVE_ADDER))
+#define GST_LIVE_ADDER_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass) ,GST_TYPE_LIVE_ADDER,GstLiveAdderClass))
+#define GST_IS_LIVE_ADDER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass) ,GST_TYPE_LIVE_ADDER))
+#define GST_LIVE_ADDER_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj) ,GST_TYPE_LIVE_ADDER,GstLiveAdderClass))
+
+typedef struct _GstLiveAdder             GstLiveAdder;
+typedef struct _GstLiveAdderClass        GstLiveAdderClass;
+
+typedef enum {
+  GST_LIVE_ADDER_FORMAT_UNSET,
+  GST_LIVE_ADDER_FORMAT_INT,
+  GST_LIVE_ADDER_FORMAT_FLOAT
+} GstLiveAdderFormat;
+
+typedef void (*GstLiveAdderFunction) (gpointer out, gpointer in, guint size);
+
+/**
+ * GstLiveAdder:
+ *
+ * The adder object structure.
+ */
+struct _GstLiveAdder {
+  GstElement      element;
+
+  GstPad         *srcpad;
+  /* pad counter, used for creating unique request pads */
+  gint            padcount;
+  GList          *sinkpads;
+
+  GstFlowReturn   srcresult;
+  GstClockID      clock_id;
+
+  /* the queue is ordered head to tail */
+  GQueue         *buffers;
+  GCond          *not_empty_cond;
+
+  GstClockTime    next_timestamp;
+
+  /* the next are valid for both int and float */
+  GstLiveAdderFormat  format;
+  gint            rate;
+  gint            channels;
+  gint            width;
+  gint            endianness;
+
+  /* the next are valid only for format == GST_LIVE_ADDER_FORMAT_INT */
+  gint            depth;
+  gboolean        is_signed;
+
+  /* number of bytes per sample, actually width/8 * channels */
+  gint            bps;
+
+  /* function to add samples */
+  GstLiveAdderFunction func;
+
+  GstClockTime    latency_ms;
+  GstClockTime    peer_latency;
+};
+
+struct _GstLiveAdderClass {
+  GstElementClass parent_class;
+};
+
+GType    gst_live_adder_get_type (void);
+
+G_END_DECLS
+
+
+#endif /* __GST_LIVE_ADDER_H__ */