gst_plugins_base/ext/ogg/gstoggdemux.c
branchRCL_3
changeset 30 7e817e7e631c
parent 0 0e761a78d257
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/ext/ogg/gstoggdemux.c	Wed Sep 01 12:16:41 2010 +0100
@@ -0,0 +1,3323 @@
+/* GStreamer
+ * Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
+ *
+ * gstoggdemux.c: ogg stream demuxer
+ *
+ * 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.
+ */
+
+/**
+ * SECTION:element-oggdemux
+ * @short_description: a demuxer for ogg files
+ *
+ * <refsect2>
+ * <para>
+ * This element demuxes ogg files into their encoded audio and video components.
+ * </para>
+ * <title>Example pipelines</title>
+ * <para>
+ * <programlisting>
+ * gst-launch -v filesrc location=test.ogg ! oggdemux ! vorbisdec ! audioconvert ! alsasink
+ * </programlisting>
+ * Decodes the vorbis audio stored inside an ogg container.
+ * </para>
+ * </refsect2>
+ *
+ * Last reviewed on 2006-12-30 (0.10.5)
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include <string.h>
+#include <gst/gst-i18n-plugin.h>
+#include <gst/base/gsttypefindhelper.h>
+
+#include "gstoggdemux.h"
+
+static const GstElementDetails gst_ogg_demux_details =
+GST_ELEMENT_DETAILS ("Ogg demuxer",
+    "Codec/Demuxer",
+    "demux ogg streams (info about ogg: http://xiph.org)",
+    "Wim Taymans <wim@fluendo.com>");
+
+#define CHUNKSIZE (8500)        /* this is out of vorbisfile */
+#define SKELETON_FISHEAD_SIZE 64
+#define SKELETON_FISBONE_MIN_SIZE 52
+
+#define GST_FLOW_LIMIT GST_FLOW_CUSTOM_ERROR
+
+GST_DEBUG_CATEGORY_STATIC (gst_ogg_demux_debug);
+GST_DEBUG_CATEGORY_STATIC (gst_ogg_demux_setup_debug);
+#define GST_CAT_DEFAULT gst_ogg_demux_debug
+
+static ogg_page *
+gst_ogg_page_copy (ogg_page * page)
+{
+  ogg_page *p = g_new0 (ogg_page, 1);
+
+  /* make a copy of the page */
+  p->header = g_memdup (page->header, page->header_len);
+  p->header_len = page->header_len;
+  p->body = g_memdup (page->body, page->body_len);
+  p->body_len = page->body_len;
+
+  return p;
+}
+
+static void
+gst_ogg_page_free (ogg_page * page)
+{
+  g_free (page->header);
+  g_free (page->body);
+  g_free (page);
+}
+
+static GstStaticPadTemplate internaltemplate =
+GST_STATIC_PAD_TEMPLATE ("internal",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS_ANY);
+
+static gboolean gst_ogg_demux_collect_chain_info (GstOggDemux * ogg,
+    GstOggChain * chain);
+static gboolean gst_ogg_demux_activate_chain (GstOggDemux * ogg,
+    GstOggChain * chain, GstEvent * event);
+static void gst_ogg_chain_mark_discont (GstOggChain * chain);
+
+static gboolean gst_ogg_demux_perform_seek (GstOggDemux * ogg,
+    GstEvent * event);
+static gboolean gst_ogg_demux_receive_event (GstElement * element,
+    GstEvent * event);
+
+static void gst_ogg_pad_class_init (GstOggPadClass * klass);
+static void gst_ogg_pad_init (GstOggPad * pad);
+static void gst_ogg_pad_dispose (GObject * object);
+static void gst_ogg_pad_finalize (GObject * object);
+
+#if 0
+static const GstFormat *gst_ogg_pad_formats (GstPad * pad);
+static const GstEventMask *gst_ogg_pad_event_masks (GstPad * pad);
+#endif
+static const GstQueryType *gst_ogg_pad_query_types (GstPad * pad);
+static gboolean gst_ogg_pad_src_query (GstPad * pad, GstQuery * query);
+static gboolean gst_ogg_pad_event (GstPad * pad, GstEvent * event);
+static GstCaps *gst_ogg_pad_getcaps (GstPad * pad);
+static GstOggPad *gst_ogg_chain_get_stream (GstOggChain * chain,
+    glong serialno);
+
+static gboolean gst_ogg_pad_query_convert (GstOggPad * pad,
+    GstFormat src_format, gint64 src_val,
+    GstFormat * dest_format, gint64 * dest_val);
+static GstClockTime gst_annodex_granule_to_time (gint64 granulepos,
+    gint64 granulerate_n, gint64 granulerate_d, guint8 granuleshift);
+
+static GstFlowReturn gst_ogg_demux_combine_flows (GstOggDemux * ogg,
+    GstOggPad * pad, GstFlowReturn ret);
+
+static GstPadClass *ogg_pad_parent_class = NULL;
+
+static GType
+gst_ogg_pad_get_type (void)
+{
+  static GType ogg_pad_type = 0;
+
+  if (!ogg_pad_type) {
+    static const GTypeInfo ogg_pad_info = {
+      sizeof (GstOggPadClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_ogg_pad_class_init,
+      NULL,
+      NULL,
+      sizeof (GstOggPad),
+      0,
+      (GInstanceInitFunc) gst_ogg_pad_init,
+    };
+
+    ogg_pad_type =
+        g_type_register_static (GST_TYPE_PAD, "GstOggPad", &ogg_pad_info, 0);
+  }
+  return ogg_pad_type;
+}
+
+static void
+gst_ogg_pad_class_init (GstOggPadClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  ogg_pad_parent_class = g_type_class_peek_parent (klass);
+
+  gobject_class->dispose = gst_ogg_pad_dispose;
+  gobject_class->finalize = gst_ogg_pad_finalize;
+}
+
+static void
+gst_ogg_pad_init (GstOggPad * pad)
+{
+  gst_pad_set_event_function (GST_PAD (pad),
+      GST_DEBUG_FUNCPTR (gst_ogg_pad_event));
+  gst_pad_set_getcaps_function (GST_PAD (pad),
+      GST_DEBUG_FUNCPTR (gst_ogg_pad_getcaps));
+  gst_pad_set_query_type_function (GST_PAD (pad),
+      GST_DEBUG_FUNCPTR (gst_ogg_pad_query_types));
+  gst_pad_set_query_function (GST_PAD (pad),
+      GST_DEBUG_FUNCPTR (gst_ogg_pad_src_query));
+
+  pad->mode = GST_OGG_PAD_MODE_INIT;
+
+  pad->first_granule = -1;
+  pad->current_granule = -1;
+
+  pad->start_time = GST_CLOCK_TIME_NONE;
+  pad->first_time = GST_CLOCK_TIME_NONE;
+
+  pad->have_type = FALSE;
+  pad->continued = NULL;
+  pad->headers = NULL;
+}
+
+static void
+gst_ogg_pad_dispose (GObject * object)
+{
+  GstOggPad *pad = GST_OGG_PAD (object);
+  GstPad **elem_pad_p;
+  GstElement **element_p;
+  GstPad **elem_out_p;
+
+  if (pad->element)
+    gst_element_set_state (pad->element, GST_STATE_NULL);
+
+  elem_pad_p = &pad->elem_pad;
+  element_p = &pad->element;
+  elem_out_p = &pad->elem_out;
+  gst_object_replace ((GstObject **) elem_pad_p, NULL);
+  gst_object_replace ((GstObject **) element_p, NULL);
+  gst_object_replace ((GstObject **) elem_out_p, NULL);
+
+  pad->chain = NULL;
+  pad->ogg = NULL;
+
+  g_list_foreach (pad->headers, (GFunc) gst_mini_object_unref, NULL);
+  g_list_free (pad->headers);
+  pad->headers = NULL;
+
+  /* clear continued pages */
+  g_list_foreach (pad->continued, (GFunc) gst_ogg_page_free, NULL);
+  g_list_free (pad->continued);
+  pad->continued = NULL;
+
+  ogg_stream_reset (&pad->stream);
+
+  G_OBJECT_CLASS (ogg_pad_parent_class)->dispose (object);
+}
+
+static void
+gst_ogg_pad_finalize (GObject * object)
+{
+  GstOggPad *pad = GST_OGG_PAD (object);
+
+  ogg_stream_clear (&pad->stream);
+
+  G_OBJECT_CLASS (ogg_pad_parent_class)->finalize (object);
+}
+
+#if 0
+static const GstFormat *
+gst_ogg_pad_formats (GstPad * pad)
+{
+  static GstFormat src_formats[] = {
+    GST_FORMAT_DEFAULT,         /* time */
+    GST_FORMAT_TIME,            /* granulepos */
+    0
+  };
+  static GstFormat sink_formats[] = {
+    GST_FORMAT_BYTES,
+    GST_FORMAT_DEFAULT,         /* bytes */
+    0
+  };
+
+  return (GST_PAD_IS_SRC (pad) ? src_formats : sink_formats);
+}
+#endif
+
+#if 0
+static const GstEventMask *
+gst_ogg_pad_event_masks (GstPad * pad)
+{
+  static const GstEventMask src_event_masks[] = {
+    {GST_EVENT_SEEK, GST_SEEK_METHOD_SET | GST_SEEK_FLAG_FLUSH},
+    {0,}
+  };
+
+  return src_event_masks;
+}
+#endif
+
+static const GstQueryType *
+gst_ogg_pad_query_types (GstPad * pad)
+{
+  static const GstQueryType query_types[] = {
+    GST_QUERY_DURATION,
+    GST_QUERY_SEEKING,
+    0
+  };
+
+  return query_types;
+}
+
+static GstCaps *
+gst_ogg_pad_getcaps (GstPad * pad)
+{
+  return gst_caps_ref (GST_PAD_CAPS (pad));
+}
+
+static gboolean
+gst_ogg_pad_src_query (GstPad * pad, GstQuery * query)
+{
+  gboolean res = TRUE;
+  GstOggDemux *ogg;
+  GstOggPad *cur;
+
+  ogg = GST_OGG_DEMUX (gst_pad_get_parent (pad));
+  cur = GST_OGG_PAD (pad);
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_DURATION:
+    {
+      GstFormat format;
+
+      gst_query_parse_duration (query, &format, NULL);
+      /* can only get position in time */
+      if (format != GST_FORMAT_TIME)
+        goto wrong_format;
+
+      /* can only return the total time position */
+      /* FIXME, return time for this specific stream */
+      gst_query_set_duration (query, GST_FORMAT_TIME, ogg->total_time);
+      break;
+    }
+    case GST_QUERY_SEEKING:
+    {
+      GstFormat format;
+
+      gst_query_parse_seeking (query, &format, NULL, NULL, NULL);
+      if (format == GST_FORMAT_TIME) {
+        gst_query_set_seeking (query, GST_FORMAT_TIME, ogg->seekable,
+            0, ogg->total_time);
+      } else {
+        res = FALSE;
+      }
+      break;
+    }
+
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+done:
+  gst_object_unref (ogg);
+
+  return res;
+
+  /* ERRORS */
+wrong_format:
+  {
+    GST_DEBUG_OBJECT (ogg, "only query duration on TIME is supported");
+    res = FALSE;
+    goto done;
+  }
+}
+
+static gboolean
+gst_ogg_demux_receive_event (GstElement * element, GstEvent * event)
+{
+  gboolean res;
+  GstOggDemux *ogg;
+
+  ogg = GST_OGG_DEMUX (element);
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+      /* can't seek if we are not seekable, FIXME could pass the
+       * seek query upstream after converting it to bytes using
+       * the average bitrate of the stream. */
+      if (!ogg->seekable) {
+        GST_DEBUG_OBJECT (ogg, "seek on non seekable stream");
+        goto error;
+      }
+
+      /* now do the seek */
+      res = gst_ogg_demux_perform_seek (ogg, event);
+      gst_event_unref (event);
+      break;
+    default:
+      GST_DEBUG_OBJECT (ogg, "We only handle seek events here");
+      goto error;
+  }
+
+  return res;
+
+  /* ERRORS */
+error:
+  {
+    GST_DEBUG_OBJECT (ogg, "error handling event");
+    gst_event_unref (event);
+    return FALSE;
+  }
+}
+
+static gboolean
+gst_ogg_pad_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res;
+  GstOggDemux *ogg;
+  GstOggPad *cur;
+
+  ogg = GST_OGG_DEMUX (gst_pad_get_parent (pad));
+  cur = GST_OGG_PAD (pad);
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+      /* can't seek if we are not seekable, FIXME could pass the
+       * seek query upstream after converting it to bytes using
+       * the average bitrate of the stream. */
+      if (!ogg->seekable) {
+        GST_DEBUG_OBJECT (ogg, "seek on non seekable stream");
+        goto error;
+      }
+
+      /* now do the seek */
+      res = gst_ogg_demux_perform_seek (ogg, event);
+      gst_event_unref (event);
+      break;
+    default:
+      res = gst_pad_event_default (pad, event);
+      break;
+  }
+done:
+  gst_object_unref (ogg);
+
+  return res;
+
+  /* ERRORS */
+error:
+  {
+    GST_DEBUG_OBJECT (ogg, "error handling event");
+    gst_event_unref (event);
+    res = FALSE;
+    goto done;
+  }
+}
+
+static void
+gst_ogg_pad_reset (GstOggPad * pad)
+{
+  ogg_stream_reset (&pad->stream);
+
+  /* clear continued pages */
+  g_list_foreach (pad->continued, (GFunc) gst_ogg_page_free, NULL);
+  g_list_free (pad->continued);
+  pad->continued = NULL;
+
+  pad->last_ret = GST_FLOW_OK;
+}
+
+/* the filter function for selecting the elements we can use in
+ * autoplugging */
+static gboolean
+gst_ogg_demux_factory_filter (GstPluginFeature * feature, GstCaps * caps)
+{
+  guint rank;
+  const gchar *klass;
+
+  /* we only care about element factories */
+  if (!GST_IS_ELEMENT_FACTORY (feature))
+    return FALSE;
+
+  klass = gst_element_factory_get_klass (GST_ELEMENT_FACTORY (feature));
+  /* only demuxers and decoders can play */
+  if (strstr (klass, "Demux") == NULL &&
+      strstr (klass, "Decoder") == NULL && strstr (klass, "Parse") == NULL) {
+    return FALSE;
+  }
+
+  /* only select elements with autoplugging rank */
+  rank = gst_plugin_feature_get_rank (feature);
+  if (rank < GST_RANK_MARGINAL)
+    return FALSE;
+
+  GST_DEBUG ("checking factory %s", GST_PLUGIN_FEATURE_NAME (feature));
+  /* now see if it is compatible with the caps */
+  {
+    GstElementFactory *factory = GST_ELEMENT_FACTORY (feature);
+    const GList *templates;
+    GList *walk;
+
+    /* get the templates from the element factory */
+    templates = gst_element_factory_get_static_pad_templates (factory);
+
+    for (walk = (GList *) templates; walk; walk = g_list_next (walk)) {
+      GstStaticPadTemplate *templ = walk->data;
+
+      /* we only care about the sink templates */
+      if (templ->direction == GST_PAD_SINK) {
+        GstCaps *intersect;
+        GstCaps *scaps;
+        gboolean empty;
+
+        /* try to intersect the caps with the caps of the template */
+        scaps = gst_static_caps_get (&templ->static_caps);
+        intersect = gst_caps_intersect (caps, scaps);
+        gst_caps_unref (scaps);
+
+        empty = gst_caps_is_empty (intersect);
+        gst_caps_unref (intersect);
+
+        /* check if the intersection is empty */
+        if (!empty) {
+          /* non empty intersection, we can use this element */
+          goto found;
+        }
+      }
+    }
+  }
+  return FALSE;
+
+found:
+  return TRUE;
+}
+
+/* function used to sort element features */
+static gint
+compare_ranks (GstPluginFeature * f1, GstPluginFeature * f2)
+{
+  gint diff;
+
+  diff = gst_plugin_feature_get_rank (f2) - gst_plugin_feature_get_rank (f1);
+  if (diff != 0)
+    return diff;
+  return strcmp (gst_plugin_feature_get_name (f2),
+      gst_plugin_feature_get_name (f1));
+}
+
+/* called when the skeleton fishead is found. Caller ensures the packet is
+ * precisely the correct size; we don't re-check this here. */
+static void
+gst_ogg_pad_parse_skeleton_fishead (GstOggPad * pad, ogg_packet * packet)
+{
+  GstOggDemux *ogg = pad->ogg;
+  guint8 *data = packet->packet;
+  guint16 major, minor;
+  gint64 prestime_n, prestime_d;
+  gint64 basetime_n, basetime_d;
+
+  /* skip "fishead\0" */
+  data += 8;
+  major = GST_READ_UINT16_LE (data);
+  data += 2;
+  minor = GST_READ_UINT16_LE (data);
+  data += 2;
+  prestime_n = (gint64) GST_READ_UINT64_LE (data);
+  data += 8;
+  prestime_d = (gint64) GST_READ_UINT64_LE (data);
+  data += 8;
+  basetime_n = (gint64) GST_READ_UINT64_LE (data);
+  data += 8;
+  basetime_d = (gint64) GST_READ_UINT64_LE (data);
+  data += 8;
+
+  ogg->basetime = gst_util_uint64_scale (GST_SECOND, basetime_n, basetime_d);
+  ogg->have_fishead = TRUE;
+  pad->is_skeleton = TRUE;
+  pad->start_time = GST_CLOCK_TIME_NONE;
+  pad->first_granule = -1;
+  pad->first_time = GST_CLOCK_TIME_NONE;
+  GST_INFO_OBJECT (ogg, "skeleton fishead parsed (basetime: %"
+      GST_TIME_FORMAT ")", GST_TIME_ARGS (ogg->basetime));
+}
+
+/* function called when a skeleton fisbone is found. Caller ensures that
+ * the packet length is sufficient */
+static void
+gst_ogg_pad_parse_skeleton_fisbone (GstOggPad * pad, ogg_packet * packet)
+{
+  GstOggPad *fisbone_pad;
+  gint64 start_granule;
+  guint32 serialno;
+  guint8 *data = packet->packet;
+
+  /* skip "fisbone\0" */
+  data += 8;
+  /* skip headers offset */
+  data += 4;
+  serialno = GST_READ_UINT32_LE (data);
+
+  fisbone_pad = gst_ogg_chain_get_stream (pad->chain, serialno);
+  if (fisbone_pad) {
+    if (fisbone_pad->have_fisbone)
+      /* already parsed */
+      return;
+
+    fisbone_pad->have_fisbone = TRUE;
+
+    data += 4;
+    /* skip number of headers */
+    data += 4;
+    fisbone_pad->granulerate_n = GST_READ_UINT64_LE (data);
+    data += 8;
+    fisbone_pad->granulerate_d = GST_READ_UINT64_LE (data);
+    data += 8;
+    start_granule = GST_READ_UINT64_LE (data);
+    data += 8;
+    fisbone_pad->preroll = GST_READ_UINT32_LE (data);
+    data += 4;
+    fisbone_pad->granuleshift = GST_READ_UINT8 (data);
+    data += 1;
+    /* padding */
+    data += 3;
+
+    fisbone_pad->start_time = gst_annodex_granule_to_time (start_granule,
+        fisbone_pad->granulerate_n, fisbone_pad->granulerate_d,
+        fisbone_pad->granuleshift);
+
+    GST_INFO_OBJECT (pad->ogg, "skeleton fisbone parsed "
+        "(serialno: %08x start time: %" GST_TIME_FORMAT
+        " granulerate_n: %" G_GINT64_FORMAT " granulerate_d: %" G_GINT64_FORMAT
+        " preroll: %" G_GUINT32_FORMAT " granuleshift: %d)",
+        serialno, GST_TIME_ARGS (fisbone_pad->start_time),
+        fisbone_pad->granulerate_n, fisbone_pad->granulerate_d,
+        fisbone_pad->preroll, fisbone_pad->granuleshift);
+  } else {
+    GST_WARNING_OBJECT (pad->ogg,
+        "found skeleton fisbone for an unknown stream %" G_GUINT32_FORMAT,
+        serialno);
+  }
+}
+
+/* function called to convert a granulepos to a timestamp */
+static gboolean
+gst_ogg_pad_query_convert (GstOggPad * pad, GstFormat src_format,
+    gint64 src_val, GstFormat * dest_format, gint64 * dest_val)
+{
+  gboolean res;
+
+  if (src_val == -1) {
+    *dest_val = -1;
+    return TRUE;
+  }
+
+  if (!pad->have_fisbone && pad->elem_pad == NULL)
+    return FALSE;
+
+  switch (src_format) {
+    case GST_FORMAT_DEFAULT:
+      if (pad->have_fisbone && *dest_format == GST_FORMAT_TIME) {
+        *dest_val = gst_annodex_granule_to_time (src_val,
+            pad->granulerate_n, pad->granulerate_d, pad->granuleshift);
+
+        res = TRUE;
+      } else {
+        if (pad->elem_pad == NULL)
+          res = FALSE;
+        else
+          res = gst_pad_query_convert (pad->elem_pad, src_format, src_val,
+              dest_format, dest_val);
+      }
+
+      break;
+    default:
+      if (pad->elem_pad == NULL)
+        res = FALSE;
+      else
+        res = gst_pad_query_convert (pad->elem_pad, src_format, src_val,
+            dest_format, dest_val);
+  }
+
+  return res;
+}
+
+/* function called by the internal decoder elements when it outputs
+ * a buffer. We use it to get the first timestamp of the stream 
+ */
+static GstFlowReturn
+gst_ogg_pad_internal_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstOggPad *oggpad;
+  GstOggDemux *ogg;
+  GstClockTime timestamp;
+
+  oggpad = gst_pad_get_element_private (pad);
+  ogg = GST_OGG_DEMUX (oggpad->ogg);
+
+  timestamp = GST_BUFFER_TIMESTAMP (buffer);
+  GST_DEBUG_OBJECT (oggpad, "received buffer from internal pad, TS=%"
+      GST_TIME_FORMAT "=%" G_GINT64_FORMAT, GST_TIME_ARGS (timestamp),
+      timestamp);
+
+  if (oggpad->start_time == GST_CLOCK_TIME_NONE) {
+    oggpad->start_time = timestamp;
+    GST_DEBUG_OBJECT (oggpad, "new start time: %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (timestamp));
+  }
+
+  gst_buffer_unref (buffer);
+
+  return GST_FLOW_OK;
+}
+
+static void
+internal_element_pad_added_cb (GstElement * element, GstPad * pad,
+    GstOggPad * oggpad)
+{
+  if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
+    if (!(gst_pad_link (pad, oggpad->elem_out) == GST_PAD_LINK_OK)) {
+      GST_ERROR ("Really couldn't find a valid pad");
+    }
+    oggpad->dynamic = FALSE;
+    g_signal_handler_disconnect (element, oggpad->padaddedid);
+    oggpad->padaddedid = 0;
+  }
+}
+
+/* runs typefind on the packet, which is assumed to be the first
+ * packet in the stream.
+ * 
+ * Based on the type returned from the typefind function, an element
+ * is created to help in conversion between granulepos and timestamps
+ * so that we can do decent seeking.
+ */
+static gboolean
+gst_ogg_pad_typefind (GstOggPad * pad, ogg_packet * packet)
+{
+  GstBuffer *buf;
+  GstCaps *caps;
+  GstElement *element = NULL;
+
+#ifndef GST_DISABLE_GST_DEBUG
+  GstOggDemux *ogg = pad->ogg;
+#endif
+
+  if (GST_PAD_CAPS (pad) != NULL)
+    return TRUE;
+
+  /* The ogg spec defines that the first packet of an ogg stream must identify
+   * the stream. Therefore ogg can use a simplified approach to typefinding
+   * and only needs to check the first packet */
+  buf = gst_buffer_new ();
+  GST_BUFFER_DATA (buf) = packet->packet;
+  GST_BUFFER_SIZE (buf) = packet->bytes;
+  GST_BUFFER_OFFSET (buf) = 0;
+
+  caps = gst_type_find_helper_for_buffer (GST_OBJECT (pad), buf, NULL);
+  gst_buffer_unref (buf);
+
+  if (caps == NULL) {
+    GST_WARNING_OBJECT (ogg,
+        "couldn't find caps for stream with serial %08x", pad->serialno);
+    caps = gst_caps_new_simple ("application/octet-stream", NULL);
+  } else {
+    /* ogg requires you to use a decoder element to define the
+     * meaning of granulepos etc so we make one. We also do this if
+     * we are in the streaming mode to calculate the first timestamp. */
+    GList *factories;
+
+    GST_LOG_OBJECT (ogg, "found caps: %" GST_PTR_FORMAT, caps);
+
+    /* first filter out the interesting element factories */
+    factories = gst_default_registry_feature_filter (
+        (GstPluginFeatureFilter) gst_ogg_demux_factory_filter, FALSE, caps);
+
+    /* sort them according to their ranks */
+    factories = g_list_sort (factories, (GCompareFunc) compare_ranks);
+
+    /* then pick the first factory to create an element */
+    if (factories) {
+      element =
+          gst_element_factory_create (GST_ELEMENT_FACTORY (factories->data),
+          NULL);
+      if (element) {
+        GstPadTemplate *template;
+
+        /* this is ours */
+        gst_object_ref (element);
+        gst_object_sink (GST_OBJECT (element));
+
+        /* FIXME, it might not be named "sink" */
+        pad->elem_pad = gst_element_get_pad (element, "sink");
+        gst_element_set_state (element, GST_STATE_PAUSED);
+        template = gst_static_pad_template_get (&internaltemplate);
+        pad->elem_out = gst_pad_new_from_template (template, "internal");
+        gst_pad_set_chain_function (pad->elem_out, gst_ogg_pad_internal_chain);
+        gst_pad_set_element_private (pad->elem_out, pad);
+        gst_pad_set_active (pad->elem_out, TRUE);
+        gst_object_unref (template);
+
+        /* and this pad may not be named src.. */
+        /* And it might also not exist at this time... */
+        {
+          GstPad *p;
+
+          p = gst_element_get_pad (element, "src");
+          if (p) {
+            gst_pad_link (p, pad->elem_out);
+            gst_object_unref (p);
+          } else {
+            pad->dynamic = TRUE;
+            pad->padaddedid = g_signal_connect (G_OBJECT (element),
+                "pad-added", G_CALLBACK (internal_element_pad_added_cb), pad);
+          }
+        }
+      }
+    }
+    g_list_free (factories);
+  }
+  pad->element = element;
+
+  gst_pad_set_caps (GST_PAD (pad), caps);
+  gst_caps_unref (caps);
+
+  return TRUE;
+}
+
+/* send packet to internal element */
+static GstFlowReturn
+gst_ogg_demux_chain_elem_pad (GstOggPad * pad, ogg_packet * packet)
+{
+  GstBuffer *buf;
+  GstFlowReturn ret;
+
+#ifndef GST_DISABLE_GST_DEBUG
+  GstOggDemux *ogg = pad->ogg;
+#endif
+
+  /* initialize our internal decoder with packets */
+  if (!pad->elem_pad)
+    goto no_decoder;
+
+  GST_DEBUG_OBJECT (ogg, "%p init decoder serial %08x", pad, pad->serialno);
+
+  buf = gst_buffer_new_and_alloc (packet->bytes);
+  memcpy (GST_BUFFER_DATA (buf), packet->packet, packet->bytes);
+  gst_buffer_set_caps (buf, GST_PAD_CAPS (pad));
+  GST_BUFFER_OFFSET (buf) = -1;
+  GST_BUFFER_OFFSET_END (buf) = packet->granulepos;
+
+  ret = gst_pad_chain (pad->elem_pad, buf);
+  if (GST_FLOW_IS_FATAL (ret))
+    goto decoder_error;
+
+  return ret;
+
+no_decoder:
+  {
+    GST_WARNING_OBJECT (ogg,
+        "pad %p does not have elem_pad, no decoder ?", pad);
+    return GST_FLOW_ERROR;
+  }
+decoder_error:
+  {
+    GST_WARNING_OBJECT (ogg, "internal decoder error");
+    return GST_FLOW_ERROR;
+  }
+}
+
+/* queue data, basically takes the packet, puts it in a buffer and store the
+ * buffer in the headers list.
+ */
+static GstFlowReturn
+gst_ogg_demux_queue_data (GstOggPad * pad, ogg_packet * packet)
+{
+  GstBuffer *buf;
+
+#ifndef GST_DISABLE_GST_DEBUG
+  GstOggDemux *ogg = pad->ogg;
+#endif
+
+  GST_DEBUG_OBJECT (ogg, "%p queueing data serial %08x", pad, pad->serialno);
+
+  buf = gst_buffer_new_and_alloc (packet->bytes);
+  memcpy (buf->data, packet->packet, packet->bytes);
+  GST_BUFFER_OFFSET (buf) = -1;
+  GST_BUFFER_OFFSET_END (buf) = packet->granulepos;
+  pad->headers = g_list_append (pad->headers, buf);
+
+  /* we are ok now */
+  return GST_FLOW_OK;
+}
+
+/* send packet to internal element */
+static GstFlowReturn
+gst_ogg_demux_chain_peer (GstOggPad * pad, ogg_packet * packet)
+{
+  GstBuffer *buf;
+  GstFlowReturn ret, cret;
+  GstOggDemux *ogg = pad->ogg;
+  GstFormat format;
+  gint64 current_time;
+  GstOggChain *chain;
+
+  GST_DEBUG_OBJECT (ogg,
+      "%p streaming to peer serial %08x", pad, pad->serialno);
+
+  ret =
+      gst_pad_alloc_buffer_and_set_caps (GST_PAD_CAST (pad),
+      GST_BUFFER_OFFSET_NONE, packet->bytes, GST_PAD_CAPS (pad), &buf);
+
+  /* combine flows */
+  cret = gst_ogg_demux_combine_flows (ogg, pad, ret);
+  if (ret != GST_FLOW_OK)
+    goto no_buffer;
+
+  /* copy packet in buffer */
+  memcpy (buf->data, packet->packet, packet->bytes);
+
+  GST_BUFFER_OFFSET (buf) = -1;
+  GST_BUFFER_OFFSET_END (buf) = packet->granulepos;
+
+  /* Mark discont on the buffer */
+  if (pad->discont) {
+    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
+    pad->discont = FALSE;
+  }
+
+  ret = gst_pad_push (GST_PAD_CAST (pad), buf);
+
+  /* combine flows */
+  cret = gst_ogg_demux_combine_flows (ogg, pad, ret);
+
+  /* we're done with skeleton stuff */
+  if (pad->is_skeleton)
+    goto done;
+
+  /* check if valid granulepos, then we can calculate the current
+   * position */
+  if (packet->granulepos < 0)
+    goto done;
+
+  /* store current granule pos */
+  ogg->current_granule = packet->granulepos;
+
+  /* convert to time */
+  format = GST_FORMAT_TIME;
+  if (!gst_ogg_pad_query_convert (pad,
+          GST_FORMAT_DEFAULT, packet->granulepos, &format,
+          (gint64 *) & current_time))
+    goto convert_failed;
+
+  /* convert to stream time */
+  if ((chain = pad->chain))
+    current_time = current_time - chain->segment_start + chain->begin_time;
+
+  /* and store as the current position */
+  gst_segment_set_last_stop (&ogg->segment, GST_FORMAT_TIME, current_time);
+
+  GST_DEBUG_OBJECT (ogg, "ogg current time %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (current_time));
+
+done:
+  /* return combined flow result */
+  return cret;
+
+  /* special cases */
+no_buffer:
+  {
+    GST_DEBUG_OBJECT (ogg,
+        "%p could not get buffer from peer %08x, %d (%s), combined %d (%s)",
+        pad, pad->serialno, ret, gst_flow_get_name (ret),
+        cret, gst_flow_get_name (cret));
+    goto done;
+  }
+convert_failed:
+  {
+    GST_WARNING_OBJECT (ogg, "could not convert granulepos to time");
+    goto done;
+  }
+}
+
+/* submit a packet to the oggpad, this function will run the
+ * typefind code for the pad if this is the first packet for this
+ * stream 
+ */
+static GstFlowReturn
+gst_ogg_pad_submit_packet (GstOggPad * pad, ogg_packet * packet)
+{
+  gint64 granule;
+  GstFlowReturn ret;
+
+  GstOggDemux *ogg = pad->ogg;
+
+  GST_DEBUG_OBJECT (ogg, "%p submit packet serial %08x", pad, pad->serialno);
+
+  if (!pad->have_type) {
+    if (!ogg->have_fishead && packet->bytes == SKELETON_FISHEAD_SIZE &&
+        !memcmp (packet->packet, "fishead\0", 8)) {
+      gst_ogg_pad_parse_skeleton_fishead (pad, packet);
+    }
+    gst_ogg_pad_typefind (pad, packet);
+    pad->have_type = TRUE;
+  }
+
+  if (ogg->have_fishead && packet->bytes >= SKELETON_FISBONE_MIN_SIZE &&
+      !memcmp (packet->packet, "fisbone\0", 8)) {
+    gst_ogg_pad_parse_skeleton_fisbone (pad, packet);
+  }
+
+  granule = packet->granulepos;
+  if (granule != -1) {
+    GST_DEBUG_OBJECT (ogg, "%p has granulepos %" G_GINT64_FORMAT, pad, granule);
+    ogg->current_granule = granule;
+    pad->current_granule = granule;
+    /* granulepos 0 and -1 are considered header packets.
+     * Note that since theora is busted, it can create non-header
+     * packets with 0 granulepos. We will correct for this when our
+     * internal decoder produced a frame and we don't have a
+     * granulepos because in that case the granulpos must have been 0 */
+    if (pad->first_granule == -1 && granule != 0) {
+      GST_DEBUG_OBJECT (ogg, "%p found first granulepos %" G_GINT64_FORMAT, pad,
+          granule);
+      pad->first_granule = granule;
+    }
+  }
+
+  if (granule != -1 && memcmp (packet->packet, "KW-DIRAC", 8) == 0) {
+    return GST_FLOW_OK;
+  }
+
+  /* no start time known, stream to internal plugin to
+   * get time. always stream to the skeleton decoder */
+  if (pad->start_time == GST_CLOCK_TIME_NONE || pad->is_skeleton) {
+    ret = gst_ogg_demux_chain_elem_pad (pad, packet);
+  }
+  /* we know the start_time of the pad data, see if we
+   * can activate the complete chain if this is a dynamic
+   * chain. */
+  if (pad->start_time != GST_CLOCK_TIME_NONE) {
+    GstOggChain *chain = pad->chain;
+
+    /* correction for busted ogg, if the internal decoder outputed
+     * a timestamp but we did not get a granulepos, it must have
+     * been 0 and the time is therefore also 0 */
+    if (pad->first_granule == -1) {
+      GST_DEBUG_OBJECT (ogg, "%p found start time without granulepos", pad);
+      pad->first_granule = 0;
+      pad->first_time = 0;
+    }
+
+    /* check if complete chain has start time */
+    if (chain == ogg->building_chain) {
+
+      /* see if we have enough info to activate the chain, we have enough info
+       * when all streams have a valid start time. */
+      if (gst_ogg_demux_collect_chain_info (ogg, chain)) {
+        GstEvent *event;
+
+        GST_DEBUG_OBJECT (ogg, "segment_start: %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (chain->segment_start));
+        GST_DEBUG_OBJECT (ogg, "segment_stop:  %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (chain->segment_stop));
+        GST_DEBUG_OBJECT (ogg, "segment_time:  %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (chain->begin_time));
+
+        /* create the newsegment event we are going to send out */
+        event = gst_event_new_new_segment (FALSE, ogg->segment.rate,
+            GST_FORMAT_TIME, chain->segment_start, chain->segment_stop,
+            chain->begin_time);
+
+        gst_ogg_demux_activate_chain (ogg, chain, event);
+
+        ogg->building_chain = NULL;
+      }
+    }
+  }
+
+  /* if we are building a chain, store buffer for when we activate
+   * it. This path is taken if we operate in streaming mode. */
+  if (ogg->building_chain) {
+    ret = gst_ogg_demux_queue_data (pad, packet);
+  }
+  /* else we are completely streaming to the peer */
+  else {
+    ret = gst_ogg_demux_chain_peer (pad, packet);
+  }
+  return ret;
+}
+
+/* flush at most @npackets from the stream layer. All packets if 
+ * @npackets is 0;
+ */
+static GstFlowReturn
+gst_ogg_pad_stream_out (GstOggPad * pad, gint npackets)
+{
+  GstFlowReturn result = GST_FLOW_OK;
+  gboolean done = FALSE;
+  GstOggDemux *ogg;
+
+  ogg = pad->ogg;
+
+  while (!done) {
+    int ret;
+    ogg_packet packet;
+
+    ret = ogg_stream_packetout (&pad->stream, &packet);
+    switch (ret) {
+      case 0:
+        GST_LOG_OBJECT (ogg, "packetout done");
+        done = TRUE;
+        break;
+      case -1:
+        GST_LOG_OBJECT (ogg, "packetout discont");
+        gst_ogg_chain_mark_discont (pad->chain);
+        break;
+      case 1:
+        GST_LOG_OBJECT (ogg, "packetout gave packet of size %ld", packet.bytes);
+        result = gst_ogg_pad_submit_packet (pad, &packet);
+        if (GST_FLOW_IS_FATAL (result))
+          goto could_not_submit;
+        break;
+      default:
+        GST_WARNING_OBJECT (ogg,
+            "invalid return value %d for ogg_stream_packetout, resetting stream",
+            ret);
+        gst_ogg_pad_reset (pad);
+        break;
+    }
+    if (npackets > 0) {
+      npackets--;
+      done = (npackets == 0);
+    }
+  }
+  return result;
+
+  /* ERRORS */
+could_not_submit:
+  {
+    GST_WARNING_OBJECT (ogg,
+        "could not submit packet for stream %08x, error: %d", pad->serialno,
+        result);
+    gst_ogg_pad_reset (pad);
+    return result;
+  }
+}
+
+/* submit a page to an oggpad, this function will then submit all
+ * the packets in the page.
+ */
+static GstFlowReturn
+gst_ogg_pad_submit_page (GstOggPad * pad, ogg_page * page)
+{
+  GstFlowReturn result = GST_FLOW_OK;
+  GstOggDemux *ogg;
+  gboolean continued = FALSE;
+
+  ogg = pad->ogg;
+
+  /* for negative rates we read pages backwards and must therefore be carefull
+   * with continued pages */
+  if (ogg->segment.rate < 0.0) {
+    gint npackets;
+
+    continued = ogg_page_continued (page);
+
+    /* number of completed packets in the page */
+    npackets = ogg_page_packets (page);
+    if (!continued) {
+      /* page is not continued so it contains at least one packet start. It's
+       * possible that no packet ends on this page (npackets == 0). In that
+       * case, the next (continued) page(s) we kept contain the remainder of the
+       * packets. We mark npackets=1 to make us start decoding the pages in the
+       * remainder of the algorithm. */
+      if (npackets == 0)
+        npackets = 1;
+    }
+    GST_LOG_OBJECT (ogg, "continued: %d, %d packets", continued, npackets);
+
+    if (npackets == 0) {
+      GST_LOG_OBJECT (ogg, "no decodable packets, we need a previous page");
+      goto done;
+    }
+  }
+
+  if (ogg_stream_pagein (&pad->stream, page) != 0)
+    goto choked;
+
+  /* flush all packets in the stream layer, this might not give a packet if
+   * the page had no packets finishing on the page (npackets == 0). */
+  result = gst_ogg_pad_stream_out (pad, 0);
+
+  if (pad->continued) {
+    ogg_packet packet;
+
+    /* now send the continued pages to the stream layer */
+    while (pad->continued) {
+      ogg_page *p = (ogg_page *) pad->continued->data;
+
+      GST_LOG_OBJECT (ogg, "submitting continued page %p", p);
+      if (ogg_stream_pagein (&pad->stream, p) != 0)
+        goto choked;
+
+      pad->continued = g_list_delete_link (pad->continued, pad->continued);
+
+      /* free the page */
+      gst_ogg_page_free (p);
+    }
+
+    GST_LOG_OBJECT (ogg, "flushing last continued packet");
+    /* flush 1 continued packet in the stream layer */
+    result = gst_ogg_pad_stream_out (pad, 1);
+
+    /* flush all remaining packets, we pushed them in the previous round.
+     * We don't use _reset() because we still want to get the discont when
+     * we submit a next page. */
+    while (ogg_stream_packetout (&pad->stream, &packet) != 0);
+  }
+
+done:
+  /* keep continued pages (only in reverse mode) */
+  if (continued) {
+    ogg_page *p = gst_ogg_page_copy (page);
+
+    GST_LOG_OBJECT (ogg, "keeping continued page %p", p);
+    pad->continued = g_list_prepend (pad->continued, p);
+  }
+
+  return result;
+
+choked:
+  {
+    GST_WARNING_OBJECT (ogg,
+        "ogg stream choked on page (serial %08x), resetting stream",
+        pad->serialno);
+    gst_ogg_pad_reset (pad);
+    /* we continue to recover */
+    return GST_FLOW_OK;
+  }
+}
+
+
+static GstOggChain *
+gst_ogg_chain_new (GstOggDemux * ogg)
+{
+  GstOggChain *chain = g_new0 (GstOggChain, 1);
+
+  GST_DEBUG_OBJECT (ogg, "creating new chain %p", chain);
+  chain->ogg = ogg;
+  chain->offset = -1;
+  chain->bytes = -1;
+  chain->have_bos = FALSE;
+  chain->streams = g_array_new (FALSE, TRUE, sizeof (GstOggPad *));
+  chain->begin_time = GST_CLOCK_TIME_NONE;
+  chain->segment_start = GST_CLOCK_TIME_NONE;
+  chain->segment_stop = GST_CLOCK_TIME_NONE;
+  chain->total_time = GST_CLOCK_TIME_NONE;
+
+  return chain;
+}
+
+static void
+gst_ogg_chain_free (GstOggChain * chain)
+{
+  gint i;
+
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    gst_object_unref (pad);
+  }
+  g_array_free (chain->streams, TRUE);
+  g_free (chain);
+}
+
+static void
+gst_ogg_chain_mark_discont (GstOggChain * chain)
+{
+  gint i;
+
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    pad->discont = TRUE;
+  }
+}
+
+static void
+gst_ogg_chain_reset (GstOggChain * chain)
+{
+  gint i;
+
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    gst_ogg_pad_reset (pad);
+  }
+}
+
+static GstOggPad *
+gst_ogg_chain_new_stream (GstOggChain * chain, glong serialno)
+{
+  GstOggPad *ret;
+  GstTagList *list;
+  gchar *name;
+
+  GST_DEBUG_OBJECT (chain->ogg, "creating new stream %08lx in chain %p",
+      serialno, chain);
+
+  ret = g_object_new (GST_TYPE_OGG_PAD, NULL);
+  /* we own this one */
+  gst_object_ref (ret);
+  gst_object_sink (ret);
+
+  GST_PAD_DIRECTION (ret) = GST_PAD_SRC;
+  ret->discont = TRUE;
+
+  ret->chain = chain;
+  ret->ogg = chain->ogg;
+
+  ret->serialno = serialno;
+  if (ogg_stream_init (&ret->stream, serialno) != 0)
+    goto init_failed;
+
+  name = g_strdup_printf ("serial_%08lx", serialno);
+  gst_object_set_name (GST_OBJECT (ret), name);
+  g_free (name);
+
+  /* FIXME: either do something with it or remove it */
+  list = gst_tag_list_new ();
+  gst_tag_list_add (list, GST_TAG_MERGE_REPLACE, GST_TAG_SERIAL, serialno,
+      NULL);
+  gst_tag_list_free (list);
+
+  GST_DEBUG_OBJECT (chain->ogg,
+      "created new ogg src %p for stream with serial %08lx", ret, serialno);
+
+  g_array_append_val (chain->streams, ret);
+
+  return ret;
+
+  /* ERRORS */
+init_failed:
+  {
+    GST_ERROR ("Could not initialize ogg_stream struct for serial %08lx.",
+        serialno);
+    gst_object_unref (ret);
+    return NULL;
+  }
+}
+
+static GstOggPad *
+gst_ogg_chain_get_stream (GstOggChain * chain, glong serialno)
+{
+  gint i;
+
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    if (pad->serialno == serialno)
+      return pad;
+  }
+  return NULL;
+}
+
+static gboolean
+gst_ogg_chain_has_stream (GstOggChain * chain, glong serialno)
+{
+  return gst_ogg_chain_get_stream (chain, serialno) != NULL;
+}
+
+#define CURRENT_CHAIN(ogg) (&g_array_index ((ogg)->chains, GstOggChain, (ogg)->current_chain))
+
+/* signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0
+      /* FILL ME */
+};
+
+static GstStaticPadTemplate ogg_demux_src_template_factory =
+GST_STATIC_PAD_TEMPLATE ("src_%d",
+    GST_PAD_SRC,
+    GST_PAD_SOMETIMES,
+    GST_STATIC_CAPS_ANY);
+
+static GstStaticPadTemplate ogg_demux_sink_template_factory =
+    GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/ogg; application/x-annodex")
+    );
+
+static void gst_ogg_demux_finalize (GObject * object);
+
+//static const GstEventMask *gst_ogg_demux_get_event_masks (GstPad * pad);
+//static const GstQueryType *gst_ogg_demux_get_query_types (GstPad * pad);
+static GstFlowReturn gst_ogg_demux_read_chain (GstOggDemux * ogg,
+    GstOggChain ** chain);
+static GstFlowReturn gst_ogg_demux_read_end_chain (GstOggDemux * ogg,
+    GstOggChain * chain);
+
+static gboolean gst_ogg_demux_sink_event (GstPad * pad, GstEvent * event);
+static void gst_ogg_demux_loop (GstOggPad * pad);
+static GstFlowReturn gst_ogg_demux_chain (GstPad * pad, GstBuffer * buffer);
+static gboolean gst_ogg_demux_sink_activate (GstPad * sinkpad);
+static gboolean gst_ogg_demux_sink_activate_pull (GstPad * sinkpad,
+    gboolean active);
+static gboolean gst_ogg_demux_sink_activate_push (GstPad * sinkpad,
+    gboolean active);
+static GstStateChangeReturn gst_ogg_demux_change_state (GstElement * element,
+    GstStateChange transition);
+static void gst_ogg_demux_send_event (GstOggDemux * ogg, GstEvent * event);
+
+static void gst_ogg_print (GstOggDemux * demux);
+
+GST_BOILERPLATE (GstOggDemux, gst_ogg_demux, GstElement, GST_TYPE_ELEMENT);
+
+static void
+gst_ogg_demux_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details (element_class, &gst_ogg_demux_details);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&ogg_demux_sink_template_factory));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&ogg_demux_src_template_factory));
+}
+static void
+gst_ogg_demux_class_init (GstOggDemuxClass * klass)
+{
+  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gstelement_class->change_state = gst_ogg_demux_change_state;
+  gstelement_class->send_event = gst_ogg_demux_receive_event;
+
+  gobject_class->finalize = gst_ogg_demux_finalize;
+}
+
+static void
+gst_ogg_demux_init (GstOggDemux * ogg, GstOggDemuxClass * g_class)
+{
+  /* create the sink pad */
+  ogg->sinkpad =
+      gst_pad_new_from_static_template (&ogg_demux_sink_template_factory,
+      "sink");
+
+  gst_pad_set_event_function (ogg->sinkpad, gst_ogg_demux_sink_event);
+  gst_pad_set_chain_function (ogg->sinkpad, gst_ogg_demux_chain);
+  gst_pad_set_activate_function (ogg->sinkpad, gst_ogg_demux_sink_activate);
+  gst_pad_set_activatepull_function (ogg->sinkpad,
+      gst_ogg_demux_sink_activate_pull);
+  gst_pad_set_activatepush_function (ogg->sinkpad,
+      gst_ogg_demux_sink_activate_push);
+  gst_element_add_pad (GST_ELEMENT (ogg), ogg->sinkpad);
+
+  ogg->chain_lock = g_mutex_new ();
+  ogg->chains = g_array_new (FALSE, TRUE, sizeof (GstOggChain *));
+
+  ogg->newsegment = NULL;
+}
+
+static void
+gst_ogg_demux_finalize (GObject * object)
+{
+  GstOggDemux *ogg;
+
+  ogg = GST_OGG_DEMUX (object);
+
+  g_array_free (ogg->chains, TRUE);
+  g_mutex_free (ogg->chain_lock);
+  ogg_sync_clear (&ogg->sync);
+
+  if (ogg->newsegment)
+    gst_event_unref (ogg->newsegment);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static gboolean
+gst_ogg_demux_sink_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res;
+  GstOggDemux *ogg;
+
+  ogg = GST_OGG_DEMUX (gst_pad_get_parent (pad));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_NEWSEGMENT:
+      /* FIXME */
+      GST_DEBUG_OBJECT (ogg, "got a new segment event");
+      ogg_sync_reset (&ogg->sync);
+      gst_event_unref (event);
+      res = TRUE;
+      break;
+    case GST_EVENT_EOS:
+    default:
+      res = gst_pad_event_default (pad, event);
+      break;
+  }
+  gst_object_unref (ogg);
+
+  return res;
+}
+
+/* submit the given buffer to the ogg sync.
+ *
+ * Returns the number of bytes submited.
+ */
+static GstFlowReturn
+gst_ogg_demux_submit_buffer (GstOggDemux * ogg, GstBuffer * buffer)
+{
+  gint size;
+  guint8 *data;
+  gchar *oggbuffer;
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  size = GST_BUFFER_SIZE (buffer);
+  data = GST_BUFFER_DATA (buffer);
+
+  GST_DEBUG_OBJECT (ogg, "submitting %u bytes", size);
+  if (G_UNLIKELY (size == 0))
+    goto done;
+
+  oggbuffer = ogg_sync_buffer (&ogg->sync, size);
+  if (G_UNLIKELY (oggbuffer == NULL))
+    goto no_buffer;
+
+  memcpy (oggbuffer, data, size);
+  if (G_UNLIKELY (ogg_sync_wrote (&ogg->sync, size) < 0))
+    goto write_failed;
+
+done:
+  gst_buffer_unref (buffer);
+
+  return ret;
+
+  /* ERRORS */
+no_buffer:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DECODE,
+        (NULL), ("failed to get ogg sync buffer"));
+    ret = GST_FLOW_ERROR;
+    goto done;
+  }
+write_failed:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DECODE,
+        (NULL), ("failed to write %d bytes to the sync buffer", size));
+    ret = GST_FLOW_ERROR;
+    goto done;
+  }
+}
+
+/* in random access mode this code updates the current read position
+ * and resets the ogg sync buffer so that the next read will happen
+ * from this new location.
+ */
+static void
+gst_ogg_demux_seek (GstOggDemux * ogg, gint64 offset)
+{
+  GST_LOG_OBJECT (ogg, "seeking to %" G_GINT64_FORMAT, offset);
+
+  ogg->offset = offset;
+  ogg_sync_reset (&ogg->sync);
+}
+
+/* read more data from the current offset and submit to
+ * the ogg sync layer.
+ */
+static GstFlowReturn
+gst_ogg_demux_get_data (GstOggDemux * ogg)
+{
+  GstFlowReturn ret;
+  GstBuffer *buffer;
+
+  GST_LOG_OBJECT (ogg, "get data %" G_GINT64_FORMAT " %" G_GINT64_FORMAT,
+      ogg->offset, ogg->length);
+  if (ogg->offset == ogg->length)
+    goto eos;
+
+  ret = gst_pad_pull_range (ogg->sinkpad, ogg->offset, CHUNKSIZE, &buffer);
+  if (ret != GST_FLOW_OK)
+    goto error;
+
+  ret = gst_ogg_demux_submit_buffer (ogg, buffer);
+
+  return ret;
+
+  /* ERROR */
+eos:
+  {
+    GST_LOG_OBJECT (ogg, "reached EOS");
+    return GST_FLOW_UNEXPECTED;
+  }
+error:
+  {
+    GST_WARNING_OBJECT (ogg, "got %d (%s) from pull range", ret,
+        gst_flow_get_name (ret));
+    return ret;
+  }
+}
+
+/* Read the next page from the current offset.
+ * boundary: number of bytes ahead we allow looking for;
+ * -1 if no boundary
+ *
+ * @offset will contain the offset the next page starts at when this function
+ * returns GST_FLOW_OK.
+ *
+ * GST_FLOW_UNEXPECTED is returned on EOS.
+ *
+ * GST_FLOW_LIMIT is returned when we did not find a page before the
+ * boundary. If @boundary is -1, this is never returned.
+ *
+ * Any other error returned while retrieving data from the peer is returned as
+ * is.
+ */
+static GstFlowReturn
+gst_ogg_demux_get_next_page (GstOggDemux * ogg, ogg_page * og, gint64 boundary,
+    gint64 * offset)
+{
+  gint64 end_offset = 0;
+  GstFlowReturn ret;
+
+  GST_LOG_OBJECT (ogg,
+      "get next page, current offset %" G_GINT64_FORMAT ", bytes boundary %"
+      G_GINT64_FORMAT, ogg->offset, boundary);
+
+  if (boundary > 0)
+    end_offset = ogg->offset + boundary;
+
+  while (TRUE) {
+    glong more;
+
+    if (boundary > 0 && ogg->offset >= end_offset)
+      goto boundary_reached;
+
+    more = ogg_sync_pageseek (&ogg->sync, og);
+
+    GST_LOG_OBJECT (ogg, "pageseek gave %ld", more);
+
+    if (more < 0) {
+      /* skipped n bytes */
+      GST_LOG_OBJECT (ogg, "skipped %ld bytes", more);
+      ogg->offset -= more;
+    } else if (more == 0) {
+      /* we need more data */
+      if (boundary == 0)
+        goto boundary_reached;
+
+      GST_LOG_OBJECT (ogg, "need more data");
+      ret = gst_ogg_demux_get_data (ogg);
+      if (ret != GST_FLOW_OK)
+        break;
+    } else {
+      gint64 res_offset = ogg->offset;
+
+      /* got a page.  Return the offset at the page beginning,
+         advance the internal offset past the page end */
+      if (offset)
+        *offset = res_offset;
+      ret = GST_FLOW_OK;
+
+      ogg->offset += more;
+      /* need to reset as we do not keep track of the bytes we
+       * sent to the sync layer */
+      ogg_sync_reset (&ogg->sync);
+
+      GST_LOG_OBJECT (ogg,
+          "got page at %" G_GINT64_FORMAT ", serial %08x, end at %"
+          G_GINT64_FORMAT ", granule %" G_GINT64_FORMAT, res_offset,
+          ogg_page_serialno (og), ogg->offset, ogg_page_granulepos (og));
+      break;
+    }
+  }
+  GST_LOG_OBJECT (ogg, "returning %d", ret);
+
+  return ret;
+
+  /* ERRORS */
+boundary_reached:
+  {
+    GST_LOG_OBJECT (ogg,
+        "offset %" G_GINT64_FORMAT " >= end_offset %" G_GINT64_FORMAT,
+        ogg->offset, end_offset);
+    return GST_FLOW_LIMIT;
+  }
+}
+
+/* from the current offset, find the previous page, seeking backwards
+ * until we find the page. 
+ */
+static GstFlowReturn
+gst_ogg_demux_get_prev_page (GstOggDemux * ogg, ogg_page * og, gint64 * offset)
+{
+  GstFlowReturn ret;
+  gint64 begin = ogg->offset;
+  gint64 end = begin;
+  gint64 cur_offset = -1;
+
+  while (cur_offset == -1) {
+    begin -= CHUNKSIZE;
+    if (begin < 0)
+      begin = 0;
+
+    /* seek CHUNKSIZE back */
+    gst_ogg_demux_seek (ogg, begin);
+
+    /* now continue reading until we run out of data, if we find a page
+     * start, we save it. It might not be the final page as there could be
+     * another page after this one. */
+    while (ogg->offset < end) {
+      gint64 new_offset;
+
+      ret =
+          gst_ogg_demux_get_next_page (ogg, og, end - ogg->offset, &new_offset);
+      /* we hit the upper limit, offset contains the last page start */
+      if (ret == GST_FLOW_LIMIT)
+        break;
+      /* something went wrong */
+      if (ret == GST_FLOW_UNEXPECTED)
+        new_offset = 0;
+      else if (ret != GST_FLOW_OK)
+        return ret;
+
+      /* offset is next page start */
+      cur_offset = new_offset;
+    }
+  }
+
+  /* we have the offset.  Actually snork and hold the page now */
+  gst_ogg_demux_seek (ogg, cur_offset);
+  ret = gst_ogg_demux_get_next_page (ogg, og, -1, NULL);
+  if (ret != GST_FLOW_OK)
+    /* this shouldn't be possible */
+    return ret;
+
+  if (offset)
+    *offset = cur_offset;
+
+  return ret;
+}
+
+static gboolean
+gst_ogg_demux_deactivate_current_chain (GstOggDemux * ogg)
+{
+  gint i;
+  GstOggChain *chain = ogg->current_chain;
+
+  if (chain == NULL)
+    return TRUE;
+
+  GST_DEBUG_OBJECT (ogg, "deactivating chain %p", chain);
+
+  /* send EOS on all the pads */
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    gst_pad_push_event (GST_PAD_CAST (pad), gst_event_new_eos ());
+
+    GST_DEBUG_OBJECT (ogg, "removing pad %" GST_PTR_FORMAT, pad);
+
+    /* deactivate first */
+    gst_pad_set_active (GST_PAD_CAST (pad), FALSE);
+
+    gst_element_remove_pad (GST_ELEMENT (ogg), GST_PAD_CAST (pad));
+  }
+  /* if we cannot seek back to the chain, we can destroy the chain 
+   * completely */
+  if (!ogg->seekable) {
+    gst_ogg_chain_free (chain);
+  }
+  ogg->current_chain = NULL;
+
+  return TRUE;
+}
+
+static gboolean
+gst_ogg_demux_activate_chain (GstOggDemux * ogg, GstOggChain * chain,
+    GstEvent * event)
+{
+  gint i;
+
+  if (chain == ogg->current_chain) {
+    if (event)
+      gst_event_unref (event);
+    return TRUE;
+  }
+
+  gst_ogg_demux_deactivate_current_chain (ogg);
+
+  /* FIXME, should not be called with NULL */
+  if (chain == NULL) {
+    ogg->current_chain = chain;
+    return TRUE;
+  }
+
+  GST_DEBUG_OBJECT (ogg, "activating chain %p", chain);
+
+  /* first add the pads */
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad;
+
+    pad = g_array_index (chain->streams, GstOggPad *, i);
+    GST_DEBUG_OBJECT (ogg, "adding pad %" GST_PTR_FORMAT, pad);
+
+    /* mark discont */
+    pad->discont = TRUE;
+    pad->last_ret = GST_FLOW_OK;
+
+    /* activate first */
+    gst_pad_set_active (GST_PAD_CAST (pad), TRUE);
+
+    gst_element_add_pad (GST_ELEMENT (ogg), GST_PAD_CAST (pad));
+  }
+
+  gst_element_no_more_pads (GST_ELEMENT (ogg));
+  ogg->current_chain = chain;
+
+  /* FIXME, must be sent from the streaming thread */
+  if (event)
+    gst_ogg_demux_send_event (ogg, event);
+
+  GST_DEBUG_OBJECT (ogg, "starting chain");
+
+  /* then send out any queued buffers */
+  for (i = 0; i < chain->streams->len; i++) {
+    GList *headers;
+    GstOggPad *pad;
+
+    pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    for (headers = pad->headers; headers; headers = g_list_next (headers)) {
+      GstBuffer *buffer = GST_BUFFER (headers->data);
+
+      if (pad->discont) {
+        GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+        pad->discont = FALSE;
+      }
+
+      /* we don't care about the return value here */
+      gst_pad_push (GST_PAD_CAST (pad), buffer);
+    }
+    /* and free the headers */
+    g_list_free (pad->headers);
+    pad->headers = NULL;
+  }
+  return TRUE;
+}
+
+/* 
+ * do seek to time @position, return FALSE or chain and TRUE
+ */
+static gboolean
+gst_ogg_demux_do_seek (GstOggDemux * ogg, gint64 position, gboolean accurate,
+    GstOggChain ** rchain)
+{
+  GstOggChain *chain = NULL;
+  gint64 begin, end;
+  gint64 begintime, endtime;
+  gint64 target;
+  gint64 best;
+  gint64 total;
+  gint64 result = 0;
+  GstFlowReturn ret;
+  gint i;
+
+  /* first find the chain to search in */
+  total = ogg->total_time;
+  if (ogg->chains->len == 0)
+    goto no_chains;
+
+  for (i = ogg->chains->len - 1; i >= 0; i--) {
+    chain = g_array_index (ogg->chains, GstOggChain *, i);
+    total -= chain->total_time;
+    if (position >= total)
+      break;
+  }
+
+  begin = chain->offset;
+  end = chain->end_offset;
+  begintime = chain->begin_time;
+  endtime = chain->begin_time + chain->total_time;
+  target = position - total + begintime;
+  if (accurate) {
+    /* FIXME, seek 4 seconds early to catch keyframes, better implement
+     * keyframe detection. */
+    target = target - (gint64) 4 *GST_SECOND;
+  }
+  target = MAX (target, 0);
+  best = begin;
+
+  GST_DEBUG_OBJECT (ogg,
+      "seeking to %" GST_TIME_FORMAT " in chain %p",
+      GST_TIME_ARGS (position), chain);
+  GST_DEBUG_OBJECT (ogg,
+      "chain offset %" G_GINT64_FORMAT ", end offset %" G_GINT64_FORMAT, begin,
+      end);
+  GST_DEBUG_OBJECT (ogg,
+      "chain begin time %" GST_TIME_FORMAT ", end time %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (begintime), GST_TIME_ARGS (endtime));
+  GST_DEBUG_OBJECT (ogg, "target %" GST_TIME_FORMAT, GST_TIME_ARGS (target));
+
+  /* perform the seek */
+  while (begin < end) {
+    gint64 bisect;
+
+    if ((end - begin < CHUNKSIZE) || (endtime == begintime)) {
+      bisect = begin;
+    } else {
+      /* take a (pretty decent) guess, avoiding overflow */
+      gint64 rate = (end - begin) * GST_MSECOND / (endtime - begintime);
+
+      bisect = (target - begintime) / GST_MSECOND * rate + begin - CHUNKSIZE;
+
+      if (bisect <= begin)
+        bisect = begin;
+      GST_DEBUG_OBJECT (ogg, "Initial guess: %" G_GINT64_FORMAT, bisect);
+    }
+    gst_ogg_demux_seek (ogg, bisect);
+
+    while (begin < end) {
+      ogg_page og;
+
+      GST_DEBUG_OBJECT (ogg,
+          "after seek, bisect %" G_GINT64_FORMAT ", begin %" G_GINT64_FORMAT
+          ", end %" G_GINT64_FORMAT, bisect, begin, end);
+
+      ret = gst_ogg_demux_get_next_page (ogg, &og, end - ogg->offset, &result);
+      GST_LOG_OBJECT (ogg, "looking for next page returned %" G_GINT64_FORMAT,
+          result);
+
+      if (ret == GST_FLOW_LIMIT) {
+        /* we hit the upper limit, go back a bit */
+        if (bisect <= begin + 1) {
+          end = begin;          /* found it */
+        } else {
+          if (bisect == 0)
+            goto seek_error;
+
+          bisect -= CHUNKSIZE;
+          if (bisect <= begin)
+            bisect = begin + 1;
+
+          gst_ogg_demux_seek (ogg, bisect);
+        }
+      } else if (ret == GST_FLOW_OK) {
+        /* found offset of next ogg page */
+        gint64 granulepos;
+        GstClockTime granuletime;
+        GstFormat format;
+        GstOggPad *pad;
+
+        GST_LOG_OBJECT (ogg, "found next ogg page at %" G_GINT64_FORMAT,
+            result);
+        granulepos = ogg_page_granulepos (&og);
+        if (granulepos == -1) {
+          GST_LOG_OBJECT (ogg, "granulepos of next page is -1");
+          continue;
+        }
+
+        pad = gst_ogg_chain_get_stream (chain, ogg_page_serialno (&og));
+        if (pad == NULL || pad->is_skeleton)
+          continue;
+
+        format = GST_FORMAT_TIME;
+        if (!gst_ogg_pad_query_convert (pad,
+                GST_FORMAT_DEFAULT, granulepos, &format,
+                (gint64 *) & granuletime)) {
+          GST_WARNING_OBJECT (ogg, "could not convert granulepos to time");
+          granuletime = target;
+        } else {
+          if (granuletime < pad->start_time)
+            continue;
+          GST_LOG_OBJECT (ogg, "granulepos %" G_GINT64_FORMAT " maps to time %"
+              GST_TIME_FORMAT, granulepos, GST_TIME_ARGS (granuletime));
+
+          granuletime -= pad->start_time;
+        }
+
+        GST_DEBUG_OBJECT (ogg,
+            "found page with granule %" G_GINT64_FORMAT " and time %"
+            GST_TIME_FORMAT, granulepos, GST_TIME_ARGS (granuletime));
+
+        if (granuletime < target) {
+          best = result;        /* raw offset of packet with granulepos */
+          begin = ogg->offset;  /* raw offset of next page */
+          begintime = granuletime;
+
+          if (target - begintime > GST_SECOND)
+            break;
+
+          bisect = begin;       /* *not* begin + 1 */
+        } else {
+          if (bisect <= begin + 1) {
+            end = begin;        /* found it */
+          } else {
+            if (end == ogg->offset) {   /* we're pretty close - we'd be stuck in */
+              end = result;
+              bisect -= CHUNKSIZE;      /* an endless loop otherwise. */
+              if (bisect <= begin)
+                bisect = begin + 1;
+              gst_ogg_demux_seek (ogg, bisect);
+            } else {
+              end = result;
+              endtime = granuletime;
+              break;
+            }
+          }
+        }
+      } else
+        goto seek_error;
+    }
+  }
+
+  ogg->offset = best;
+  *rchain = chain;
+
+  return TRUE;
+
+no_chains:
+  {
+    GST_DEBUG_OBJECT (ogg, "no chains");
+    return FALSE;
+  }
+seek_error:
+  {
+    GST_DEBUG_OBJECT (ogg, "got a seek error");
+    return FALSE;
+  }
+}
+
+/* does not take ownership of the event */
+static gboolean
+gst_ogg_demux_perform_seek (GstOggDemux * ogg, GstEvent * event)
+{
+  GstOggChain *chain = NULL;
+  gboolean res;
+  gboolean flush, accurate;
+  GstFormat format;
+  gdouble rate;
+  GstSeekFlags flags;
+  GstSeekType cur_type, stop_type;
+  gint64 cur, stop;
+  gboolean update;
+
+  if (event) {
+    GST_DEBUG_OBJECT (ogg, "seek with event");
+
+    gst_event_parse_seek (event, &rate, &format, &flags,
+        &cur_type, &cur, &stop_type, &stop);
+
+    /* we can only seek on time */
+    if (format != GST_FORMAT_TIME) {
+      GST_DEBUG_OBJECT (ogg, "can only seek on TIME");
+      goto error;
+    }
+  } else {
+    GST_DEBUG_OBJECT (ogg, "seek without event");
+
+    flags = 0;
+    rate = 1.0;
+  }
+
+  GST_DEBUG_OBJECT (ogg, "seek, rate %g", rate);
+
+  flush = flags & GST_SEEK_FLAG_FLUSH;
+  accurate = flags & GST_SEEK_FLAG_ACCURATE;
+
+  /* first step is to unlock the streaming thread if it is
+   * blocked in a chain call, we do this by starting the flush. because
+   * we cannot yet hold any streaming lock, we have to protect the chains
+   * with their own lock. */
+  if (flush) {
+    gint i;
+
+    gst_pad_push_event (ogg->sinkpad, gst_event_new_flush_start ());
+
+    GST_CHAIN_LOCK (ogg);
+    for (i = 0; i < ogg->chains->len; i++) {
+      GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+      gint j;
+
+      for (j = 0; j < chain->streams->len; j++) {
+        GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, j);
+
+        gst_pad_push_event (GST_PAD (pad), gst_event_new_flush_start ());
+      }
+    }
+    GST_CHAIN_UNLOCK (ogg);
+  } else {
+    gst_pad_pause_task (ogg->sinkpad);
+  }
+
+  /* now grab the stream lock so that streaming cannot continue, for
+   * non flushing seeks when the element is in PAUSED this could block
+   * forever. */
+  GST_PAD_STREAM_LOCK (ogg->sinkpad);
+
+  if (ogg->segment_running && !flush) {
+    /* create the segment event to close the current segment */
+    if ((chain = ogg->current_chain)) {
+      GstEvent *newseg;
+
+      newseg = gst_event_new_new_segment (TRUE, ogg->segment.rate,
+          GST_FORMAT_TIME, ogg->segment.start + chain->segment_start,
+          ogg->segment.last_stop + chain->segment_start, ogg->segment.time);
+
+      /* send segment on old chain, FIXME, must be sent from streaming thread. */
+      gst_ogg_demux_send_event (ogg, newseg);
+    }
+  }
+
+  if (event) {
+    gst_segment_set_seek (&ogg->segment, rate, format, flags,
+        cur_type, cur, stop_type, stop, &update);
+  }
+
+  GST_DEBUG_OBJECT (ogg, "segment positions set to %" GST_TIME_FORMAT "-%"
+      GST_TIME_FORMAT, GST_TIME_ARGS (ogg->segment.start),
+      GST_TIME_ARGS (ogg->segment.stop));
+
+  /* we need to stop flushing on the srcpad as we're going to use it
+   * next. We can do this as we have the STREAM lock now. */
+  gst_pad_push_event (ogg->sinkpad, gst_event_new_flush_stop ());
+
+  {
+    gint i;
+
+    /* reset all ogg streams now, need to do this from within the lock to
+     * make sure the streaming thread is not messing with the stream */
+    for (i = 0; i < ogg->chains->len; i++) {
+      GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+
+      gst_ogg_chain_reset (chain);
+    }
+  }
+
+  res = gst_ogg_demux_do_seek (ogg, ogg->segment.last_stop, accurate, &chain);
+
+  /* seek failed, make sure we continue the current chain */
+  if (!res) {
+    chain = ogg->current_chain;
+  }
+
+  if (!chain)
+    goto no_chain;
+
+  /* now we have a new position, prepare for streaming again */
+  {
+    GstEvent *event;
+    gint64 stop;
+    gint64 start;
+    gint64 last_stop, begin_time;
+
+    /* we have to send the flush to the old chain, not the new one */
+    if (flush)
+      gst_ogg_demux_send_event (ogg, gst_event_new_flush_stop ());
+
+    /* we need this to see how far inside the chain we need to start */
+    if (chain->begin_time != GST_CLOCK_TIME_NONE)
+      begin_time = chain->begin_time;
+    else
+      begin_time = 0;
+
+    /* segment.start gives the start over all chains, we calculate the amount
+     * of time into this chain we need to start */
+    start = ogg->segment.start - begin_time;
+    if (chain->segment_start != GST_CLOCK_TIME_NONE)
+      start += chain->segment_start;
+
+    if ((stop = ogg->segment.stop) == -1)
+      stop = ogg->segment.duration;
+
+    /* segment.stop gives the stop time over all chains, calculate the amount of
+     * time we need to stop in this chain */
+    if (stop != -1) {
+      if (stop > begin_time)
+        stop -= begin_time;
+      else
+        stop = 0;
+      stop += chain->segment_start;
+      /* we must stop when this chain ends and switch to the next chain to play
+       * the remainder of the segment. */
+      stop = MIN (stop, chain->segment_stop);
+    }
+
+    last_stop = ogg->segment.last_stop - begin_time;
+    if (chain->segment_start != GST_CLOCK_TIME_NONE)
+      last_stop += chain->segment_start;
+
+    /* create the segment event we are going to send out */
+    if (ogg->segment.rate >= 0.0)
+      event = gst_event_new_new_segment (FALSE, ogg->segment.rate,
+          ogg->segment.format, last_stop, stop, ogg->segment.time);
+    else
+      event = gst_event_new_new_segment (FALSE, ogg->segment.rate,
+          ogg->segment.format, start, last_stop, ogg->segment.time);
+
+    if (chain != ogg->current_chain) {
+      /* switch to different chain, send segment on new chain */
+      gst_ogg_demux_activate_chain (ogg, chain, event);
+    } else {
+      /* mark discont and send segment on current chain */
+      gst_ogg_chain_mark_discont (chain);
+      /* This event should be sent from the streaming thread (sink pad task) */
+      if (ogg->newsegment)
+        gst_event_unref (ogg->newsegment);
+      ogg->newsegment = event;
+    }
+
+    /* notify start of new segment */
+    if (ogg->segment.flags & GST_SEEK_FLAG_SEGMENT) {
+      gst_element_post_message (GST_ELEMENT (ogg),
+          gst_message_new_segment_start (GST_OBJECT (ogg),
+              GST_FORMAT_TIME, ogg->segment.last_stop));
+    }
+
+    ogg->segment_running = TRUE;
+    /* restart our task since it might have been stopped when we did the 
+     * flush. */
+    gst_pad_start_task (ogg->sinkpad, (GstTaskFunction) gst_ogg_demux_loop,
+        ogg->sinkpad);
+  }
+
+  /* streaming can continue now */
+  GST_PAD_STREAM_UNLOCK (ogg->sinkpad);
+
+  return res;
+
+error:
+  {
+    GST_DEBUG_OBJECT (ogg, "seek failed");
+    return FALSE;
+  }
+no_chain:
+  {
+    GST_DEBUG_OBJECT (ogg, "no chain to seek in");
+    GST_PAD_STREAM_UNLOCK (ogg->sinkpad);
+    return FALSE;
+  }
+}
+
+/* finds each bitstream link one at a time using a bisection search
+ * (has to begin by knowing the offset of the lb's initial page).
+ * Recurses for each link so it can alloc the link storage after
+ * finding them all, then unroll and fill the cache at the same time 
+ */
+static GstFlowReturn
+gst_ogg_demux_bisect_forward_serialno (GstOggDemux * ogg,
+    gint64 begin, gint64 searched, gint64 end, GstOggChain * chain, glong m)
+{
+  gint64 endsearched = end;
+  gint64 next = end;
+  ogg_page og;
+  GstFlowReturn ret;
+  gint64 offset;
+  GstOggChain *nextchain;
+
+  GST_LOG_OBJECT (ogg,
+      "bisect begin: %" G_GINT64_FORMAT ", searched: %" G_GINT64_FORMAT
+      ", end %" G_GINT64_FORMAT ", chain: %p", begin, searched, end, chain);
+
+  /* the below guards against garbage seperating the last and
+   * first pages of two links. */
+  while (searched < endsearched) {
+    gint64 bisect;
+
+    if (endsearched - searched < CHUNKSIZE) {
+      bisect = searched;
+    } else {
+      bisect = (searched + endsearched) / 2;
+    }
+
+    gst_ogg_demux_seek (ogg, bisect);
+    ret = gst_ogg_demux_get_next_page (ogg, &og, -1, &offset);
+
+    if (ret == GST_FLOW_UNEXPECTED) {
+      endsearched = bisect;
+    } else if (ret == GST_FLOW_OK) {
+      glong serial = ogg_page_serialno (&og);
+
+      if (!gst_ogg_chain_has_stream (chain, serial)) {
+        endsearched = bisect;
+        next = offset;
+      } else {
+        searched = offset + og.header_len + og.body_len;
+      }
+    } else
+      return ret;
+  }
+
+  GST_LOG_OBJECT (ogg, "current chain ends at %" G_GINT64_FORMAT, searched);
+
+  chain->end_offset = searched;
+  ret = gst_ogg_demux_read_end_chain (ogg, chain);
+  if (ret != GST_FLOW_OK)
+    return ret;
+
+  GST_LOG_OBJECT (ogg, "found begin at %" G_GINT64_FORMAT, next);
+
+  gst_ogg_demux_seek (ogg, next);
+  ret = gst_ogg_demux_read_chain (ogg, &nextchain);
+  if (ret == GST_FLOW_UNEXPECTED) {
+    nextchain = NULL;
+    ret = GST_FLOW_OK;
+    GST_LOG_OBJECT (ogg, "no next chain");
+  } else if (ret != GST_FLOW_OK)
+    goto done;
+
+  if (searched < end && nextchain != NULL) {
+    ret = gst_ogg_demux_bisect_forward_serialno (ogg, next, ogg->offset,
+        end, nextchain, m + 1);
+    if (ret != GST_FLOW_OK)
+      goto done;
+  }
+  GST_LOG_OBJECT (ogg, "adding chain %p", chain);
+
+  g_array_insert_val (ogg->chains, 0, chain);
+
+done:
+  return ret;
+}
+
+/* read a chain from the ogg file. This code will
+ * read all BOS pages and will create and return a GstOggChain 
+ * structure with the results. 
+ * 
+ * This function will also read N pages from each stream in the
+ * chain and submit them to the decoders. When the decoder has
+ * decoded the first buffer, we know the timestamp of the first
+ * page in the chain.
+ */
+static GstFlowReturn
+gst_ogg_demux_read_chain (GstOggDemux * ogg, GstOggChain ** res_chain)
+{
+  GstFlowReturn ret;
+  GstOggChain *chain = NULL;
+  gint64 offset = ogg->offset;
+  ogg_page op;
+  gboolean done;
+  gint i;
+
+  GST_LOG_OBJECT (ogg, "reading chain at %" G_GINT64_FORMAT, offset);
+
+  /* first read the BOS pages, do typefind on them, create
+   * the decoders, send data to the decoders. */
+  while (TRUE) {
+    GstOggPad *pad;
+    glong serial;
+
+    ret = gst_ogg_demux_get_next_page (ogg, &op, -1, NULL);
+    if (ret != GST_FLOW_OK) {
+      GST_WARNING_OBJECT (ogg, "problem reading BOS page: ret=%d", ret);
+      break;
+    }
+    if (!ogg_page_bos (&op)) {
+      GST_WARNING_OBJECT (ogg, "page is not BOS page");
+      break;
+    }
+
+    if (chain == NULL) {
+      chain = gst_ogg_chain_new (ogg);
+      chain->offset = offset;
+    }
+
+    serial = ogg_page_serialno (&op);
+    if (gst_ogg_chain_get_stream (chain, serial) != NULL) {
+      GST_WARNING_OBJECT (ogg, "found serial %08lx BOS page twice, ignoring",
+          serial);
+      continue;
+    }
+
+    pad = gst_ogg_chain_new_stream (chain, serial);
+    gst_ogg_pad_submit_page (pad, &op);
+  }
+
+  if (ret != GST_FLOW_OK || chain == NULL) {
+    if (ret != GST_FLOW_UNEXPECTED) {
+      GST_WARNING_OBJECT (ogg, "failed to read chain");
+    } else {
+      GST_DEBUG_OBJECT (ogg, "done reading chains");
+    }
+    if (chain) {
+      gst_ogg_chain_free (chain);
+    }
+    if (res_chain)
+      *res_chain = NULL;
+    return ret;
+  }
+
+  chain->have_bos = TRUE;
+  GST_LOG_OBJECT (ogg, "read bos pages, init decoder now");
+
+  /* now read pages until we receive a buffer from each of the
+   * stream decoders, this will tell us the timestamp of the
+   * first packet in the chain then */
+
+  /* save the offset to the first non bos page in the chain: if searching for
+   * pad->first_time we read past the end of the chain, we'll seek back to this
+   * position
+   */
+  offset = ogg->offset;
+
+  done = FALSE;
+  while (!done) {
+    glong serial;
+    gboolean known_serial = FALSE;
+    GstFlowReturn ret;
+
+    serial = ogg_page_serialno (&op);
+    done = TRUE;
+    for (i = 0; i < chain->streams->len; i++) {
+      GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+      GST_LOG_OBJECT (ogg, "serial %08x time %" GST_TIME_FORMAT, pad->serialno,
+          GST_TIME_ARGS (pad->start_time));
+
+      if (pad->serialno == serial) {
+        known_serial = TRUE;
+
+        /* submit the page now, this will fill in the start_time when the
+         * internal decoder finds it */
+        gst_ogg_pad_submit_page (pad, &op);
+
+        if (!pad->is_skeleton && pad->start_time == -1 && ogg_page_eos (&op)) {
+          /* got EOS on a pad before we could find its start_time.
+           * We have no chance of finding a start_time for every pad so
+           * stop searching for the other start_time(s).
+           */
+          done = TRUE;
+          break;
+        }
+      }
+      /* the timestamp will be filled in when we submit the pages */
+      if (!pad->is_skeleton)
+        done &= (pad->start_time != GST_CLOCK_TIME_NONE);
+
+      GST_LOG_OBJECT (ogg, "done %08x now %d", pad->serialno, done);
+    }
+
+    /* we read a page not belonging to the current chain: seek back to the
+     * beginning of the chain
+     */
+    if (!known_serial) {
+      GST_LOG_OBJECT (ogg, "unknown serial %08lx", serial);
+      gst_ogg_demux_seek (ogg, offset);
+      break;
+    }
+
+    if (!done) {
+      ret = gst_ogg_demux_get_next_page (ogg, &op, -1, NULL);
+      if (ret != GST_FLOW_OK)
+        break;
+    }
+  }
+  GST_LOG_OBJECT (ogg, "done reading chain");
+  /* now we can fill in the missing info using queries */
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+    GstFormat target;
+
+    if (pad->is_skeleton)
+      continue;
+
+    GST_LOG_OBJECT (ogg, "convert first granule %" G_GUINT64_FORMAT " to time ",
+        pad->first_granule);
+
+    target = GST_FORMAT_TIME;
+    if (!gst_ogg_pad_query_convert (pad,
+            GST_FORMAT_DEFAULT, pad->first_granule, &target,
+            (gint64 *) & pad->first_time)) {
+      GST_WARNING_OBJECT (ogg, "could not convert granulepos to time");
+    } else {
+      GST_LOG_OBJECT (ogg, "converted to first time %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (pad->first_time));
+    }
+
+    pad->mode = GST_OGG_PAD_MODE_STREAMING;
+  }
+
+  if (res_chain)
+    *res_chain = chain;
+
+  return GST_FLOW_OK;
+}
+
+/* read the last pages from the ogg stream to get the final
+ * page end_offsets.
+ */
+static GstFlowReturn
+gst_ogg_demux_read_end_chain (GstOggDemux * ogg, GstOggChain * chain)
+{
+  gint64 begin = chain->end_offset;
+  gint64 end = begin;
+  gint64 last_granule = -1;
+  GstOggPad *last_pad = NULL;
+  GstFormat target;
+  GstFlowReturn ret;
+  gboolean done = FALSE;
+  ogg_page og;
+  gint i;
+
+  while (!done) {
+    begin -= CHUNKSIZE;
+    if (begin < 0)
+      begin = 0;
+
+    gst_ogg_demux_seek (ogg, begin);
+
+    /* now continue reading until we run out of data, if we find a page
+     * start, we save it. It might not be the final page as there could be
+     * another page after this one. */
+    while (ogg->offset < end) {
+      ret = gst_ogg_demux_get_next_page (ogg, &og, end - ogg->offset, NULL);
+
+      if (ret == GST_FLOW_LIMIT)
+        break;
+      if (ret != GST_FLOW_OK)
+        return ret;
+
+      for (i = 0; i < chain->streams->len; i++) {
+        GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+        if (pad->is_skeleton)
+          continue;
+
+        if (pad->serialno == ogg_page_serialno (&og)) {
+          gint64 granulepos = ogg_page_granulepos (&og);
+
+          if (last_granule < granulepos) {
+            last_granule = granulepos;
+            last_pad = pad;
+          }
+          done = TRUE;
+          break;
+        }
+      }
+    }
+  }
+
+  target = GST_FORMAT_TIME;
+  if (last_granule == -1 || !gst_ogg_pad_query_convert (last_pad,
+          GST_FORMAT_DEFAULT, last_granule, &target,
+          (gint64 *) & chain->segment_stop)) {
+    GST_WARNING_OBJECT (ogg, "could not convert granulepos to time");
+    chain->segment_stop = GST_CLOCK_TIME_NONE;
+  }
+
+  return GST_FLOW_OK;
+}
+
+/* find a pad with a given serial number
+ */
+static GstOggPad *
+gst_ogg_demux_find_pad (GstOggDemux * ogg, int serialno)
+{
+  GstOggPad *pad;
+  gint i;
+
+  /* first look in building chain if any */
+  if (ogg->building_chain) {
+    pad = gst_ogg_chain_get_stream (ogg->building_chain, serialno);
+    if (pad)
+      return pad;
+  }
+
+  /* then look in current chain if any */
+  if (ogg->current_chain) {
+    pad = gst_ogg_chain_get_stream (ogg->current_chain, serialno);
+    if (pad)
+      return pad;
+  }
+
+  for (i = 0; i < ogg->chains->len; i++) {
+    GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+
+    pad = gst_ogg_chain_get_stream (chain, serialno);
+    if (pad)
+      return pad;
+  }
+  return NULL;
+}
+
+/* find a chain with a given serial number
+ */
+static GstOggChain *
+gst_ogg_demux_find_chain (GstOggDemux * ogg, int serialno)
+{
+  GstOggPad *pad;
+
+  pad = gst_ogg_demux_find_pad (ogg, serialno);
+  if (pad) {
+    return pad->chain;
+  }
+  return NULL;
+}
+
+/* returns TRUE if all streams have valid start time */
+static gboolean
+gst_ogg_demux_collect_chain_info (GstOggDemux * ogg, GstOggChain * chain)
+{
+  gint i;
+  gboolean res = TRUE;
+
+  chain->total_time = GST_CLOCK_TIME_NONE;
+  chain->segment_start = G_MAXUINT64;
+
+  GST_DEBUG_OBJECT (ogg, "trying to collect chain info");
+
+  for (i = 0; i < chain->streams->len; i++) {
+    GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+    if (pad->is_skeleton)
+      continue;
+
+    /*  can do this if the pad start time is not defined */
+    if (pad->start_time == GST_CLOCK_TIME_NONE)
+      res = FALSE;
+    else
+      chain->segment_start = MIN (chain->segment_start, pad->start_time);
+  }
+
+  if (chain->segment_stop != GST_CLOCK_TIME_NONE
+      && chain->segment_start != G_MAXUINT64)
+    chain->total_time = chain->segment_stop - chain->segment_start;
+
+  GST_DEBUG_OBJECT (ogg, "return %d", res);
+
+  return res;
+}
+
+static void
+gst_ogg_demux_collect_info (GstOggDemux * ogg)
+{
+  gint i;
+
+  /* collect all info */
+  ogg->total_time = 0;
+
+  for (i = 0; i < ogg->chains->len; i++) {
+    GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+
+    chain->begin_time = ogg->total_time;
+
+    gst_ogg_demux_collect_chain_info (ogg, chain);
+
+    ogg->total_time += chain->total_time;
+  }
+  gst_segment_set_duration (&ogg->segment, GST_FORMAT_TIME, ogg->total_time);
+}
+
+/* find all the chains in the ogg file, this reads the first and
+ * last page of the ogg stream, if they match then the ogg file has
+ * just one chain, else we do a binary search for all chains.
+ */
+static GstFlowReturn
+gst_ogg_demux_find_chains (GstOggDemux * ogg)
+{
+  ogg_page og;
+  GstPad *peer;
+  GstFormat format;
+  gboolean res;
+  gulong serialno;
+  GstOggChain *chain;
+  GstFlowReturn ret;
+
+  /* get peer to figure out length */
+  if ((peer = gst_pad_get_peer (ogg->sinkpad)) == NULL)
+    goto no_peer;
+
+  /* find length to read last page, we store this for later use. */
+  format = GST_FORMAT_BYTES;
+  res = gst_pad_query_duration (peer, &format, &ogg->length);
+  gst_object_unref (peer);
+  if (!res || ogg->length <= 0)
+    goto no_length;
+
+  GST_DEBUG_OBJECT (ogg, "file length %" G_GINT64_FORMAT, ogg->length);
+
+  /* read chain from offset 0, this is the first chain of the
+   * ogg file. */
+  gst_ogg_demux_seek (ogg, 0);
+  ret = gst_ogg_demux_read_chain (ogg, &chain);
+  if (ret != GST_FLOW_OK)
+    goto no_first_chain;
+
+  /* read page from end offset, we use this page to check if its serial
+   * number is contained in the first chain. If this is the case then
+   * this ogg is not a chained ogg and we can skip the scanning. */
+  gst_ogg_demux_seek (ogg, ogg->length);
+  ret = gst_ogg_demux_get_prev_page (ogg, &og, NULL);
+  if (ret != GST_FLOW_OK)
+    goto no_last_page;
+
+  serialno = ogg_page_serialno (&og);
+
+  if (!gst_ogg_chain_has_stream (chain, serialno)) {
+    /* the last page is not in the first stream, this means we should
+     * find all the chains in this chained ogg. */
+    ret =
+        gst_ogg_demux_bisect_forward_serialno (ogg, 0, 0, ogg->length, chain,
+        0);
+  } else {
+    /* we still call this function here but with an empty range so that
+     * we can reuse the setup code in this routine. */
+    ret =
+        gst_ogg_demux_bisect_forward_serialno (ogg, 0, ogg->length, ogg->length,
+        chain, 0);
+  }
+  if (ret != GST_FLOW_OK)
+    goto done;
+
+  /* all fine, collect and print */
+  gst_ogg_demux_collect_info (ogg);
+
+  /* dump our chains and streams */
+  gst_ogg_print (ogg);
+
+done:
+  return ret;
+
+  /*** error cases ***/
+no_peer:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DEMUX, (NULL), ("we don't have a peer"));
+    return GST_FLOW_NOT_LINKED;
+  }
+no_length:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DEMUX, (NULL), ("can't get file length"));
+    return GST_FLOW_NOT_SUPPORTED;
+  }
+no_first_chain:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DEMUX, (NULL), ("can't get first chain"));
+    return GST_FLOW_ERROR;
+  }
+no_last_page:
+  {
+    GST_DEBUG_OBJECT (ogg, "can't get last page");
+    if (chain)
+      gst_ogg_chain_free (chain);
+    return ret;
+  }
+}
+
+static GstFlowReturn
+gst_ogg_demux_handle_page (GstOggDemux * ogg, ogg_page * page)
+{
+  GstOggPad *pad;
+  gint64 granule;
+  guint serialno;
+  GstFlowReturn result = GST_FLOW_OK;
+
+  serialno = ogg_page_serialno (page);
+  granule = ogg_page_granulepos (page);
+
+  GST_LOG_OBJECT (ogg,
+      "processing ogg page (serial %08x, pageno %ld, granulepos %"
+      G_GINT64_FORMAT ", bos %d)",
+      serialno, ogg_page_pageno (page), granule, ogg_page_bos (page));
+
+  if (ogg_page_bos (page)) {
+    GstOggChain *chain;
+
+    /* first page */
+    /* see if we know about the chain already */
+    chain = gst_ogg_demux_find_chain (ogg, serialno);
+    if (chain) {
+      GstEvent *event;
+
+      /* create the newsegment event we are going to send out */
+      event = gst_event_new_new_segment (FALSE, ogg->segment.rate,
+          GST_FORMAT_TIME, chain->segment_start, chain->segment_stop,
+          chain->begin_time);
+
+      GST_DEBUG_OBJECT (ogg,
+          "segment: start %" GST_TIME_FORMAT ", stop %" GST_TIME_FORMAT
+          ", time %" GST_TIME_FORMAT, GST_TIME_ARGS (chain->segment_start),
+          GST_TIME_ARGS (chain->segment_stop),
+          GST_TIME_ARGS (chain->begin_time));
+
+      /* activate it as it means we have a non-header */
+      gst_ogg_demux_activate_chain (ogg, chain, event);
+      pad = gst_ogg_demux_find_pad (ogg, serialno);
+    } else {
+      GstClockTime chain_time;
+      GstOggChain *current_chain;
+      gint64 current_time;
+
+      /* this can only happen in non-seekabe mode */
+      if (ogg->seekable)
+        goto unknown_chain;
+
+      current_chain = ogg->current_chain;
+      current_time = ogg->segment.last_stop;
+
+      if (current_chain) {
+        /* remove existing pads */
+        gst_ogg_demux_deactivate_current_chain (ogg);
+      }
+      /* time of new chain is current time */
+      chain_time = current_time;
+
+      if (ogg->building_chain == NULL) {
+        GstOggChain *newchain;
+
+        newchain = gst_ogg_chain_new (ogg);
+        newchain->offset = 0;
+        /* set new chain begin time aligned with end time of old chain */
+        newchain->begin_time = chain_time;
+        GST_DEBUG_OBJECT (ogg, "new chain, begin time %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (chain_time));
+
+        /* and this is the one we are building now */
+        ogg->building_chain = newchain;
+      }
+      pad = gst_ogg_chain_new_stream (ogg->building_chain, serialno);
+    }
+  } else {
+    pad = gst_ogg_demux_find_pad (ogg, serialno);
+  }
+  if (pad) {
+    result = gst_ogg_pad_submit_page (pad, page);
+  } else {
+    /* no pad, this is pretty fatal. This means an ogg page without bos
+     * has been seen for this serialno. could just ignore it too... */
+    goto unknown_pad;
+  }
+  return result;
+
+  /* ERRORS */
+unknown_chain:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DECODE,
+        (NULL), ("unknown ogg chain for serial %08x detected", serialno));
+    return GST_FLOW_ERROR;
+  }
+unknown_pad:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DECODE,
+        (NULL), ("unknown ogg pad for serial %08x detected", serialno));
+    return GST_FLOW_ERROR;
+  }
+}
+
+/* streaming mode, receive a buffer, parse it, create pads for
+ * the serialno, submit pages and packets to the oggpads
+ */
+static GstFlowReturn
+gst_ogg_demux_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstOggDemux *ogg;
+  gint ret;
+  GstFlowReturn result = GST_FLOW_OK;
+
+  ogg = GST_OGG_DEMUX (GST_OBJECT_PARENT (pad));
+
+  GST_DEBUG_OBJECT (ogg, "chain");
+  result = gst_ogg_demux_submit_buffer (ogg, buffer);
+
+  while (result == GST_FLOW_OK) {
+    ogg_page page;
+
+    ret = ogg_sync_pageout (&ogg->sync, &page);
+    if (ret == 0)
+      /* need more data */
+      break;
+    if (ret == -1) {
+      /* discontinuity in the pages */
+      GST_DEBUG_OBJECT (ogg, "discont in page found, continuing");
+    } else {
+      result = gst_ogg_demux_handle_page (ogg, &page);
+    }
+  }
+  return result;
+}
+
+static void
+gst_ogg_demux_send_event (GstOggDemux * ogg, GstEvent * event)
+{
+  GstOggChain *chain = ogg->current_chain;
+
+  if (chain) {
+    gint i;
+
+    for (i = 0; i < chain->streams->len; i++) {
+      GstOggPad *pad = g_array_index (chain->streams, GstOggPad *, i);
+
+      gst_event_ref (event);
+      GST_DEBUG_OBJECT (ogg, "Pushing event on pad %p", pad);
+      gst_pad_push_event (GST_PAD (pad), event);
+    }
+  }
+  gst_event_unref (event);
+}
+
+static GstFlowReturn
+gst_ogg_demux_combine_flows (GstOggDemux * ogg, GstOggPad * pad,
+    GstFlowReturn ret)
+{
+  GstOggChain *chain;
+
+  /* store the value */
+  pad->last_ret = ret;
+
+  /* any other error that is not-linked can be returned right
+   * away */
+  if (ret != GST_FLOW_NOT_LINKED)
+    goto done;
+
+  /* only return NOT_LINKED if all other pads returned NOT_LINKED */
+  chain = ogg->current_chain;
+  if (chain) {
+    gint i;
+
+    for (i = 0; i < chain->streams->len; i++) {
+      GstOggPad *opad = g_array_index (chain->streams, GstOggPad *, i);
+
+      ret = opad->last_ret;
+      /* some other return value (must be SUCCESS but we can return
+       * other values as well) */
+      if (ret != GST_FLOW_NOT_LINKED)
+        goto done;
+    }
+    /* if we get here, all other pads were unlinked and we return
+     * NOT_LINKED then */
+  }
+done:
+  return ret;
+}
+
+static GstFlowReturn
+gst_ogg_demux_loop_forward (GstOggDemux * ogg)
+{
+  GstFlowReturn ret;
+  GstBuffer *buffer;
+
+  if (ogg->offset == ogg->length) {
+    GST_LOG_OBJECT (ogg, "no more data to pull %" G_GINT64_FORMAT
+        " == %" G_GINT64_FORMAT, ogg->offset, ogg->length);
+    ret = GST_FLOW_UNEXPECTED;
+    goto done;
+  }
+
+  GST_LOG_OBJECT (ogg, "pull data %" G_GINT64_FORMAT, ogg->offset);
+  ret = gst_pad_pull_range (ogg->sinkpad, ogg->offset, CHUNKSIZE, &buffer);
+  if (ret != GST_FLOW_OK) {
+    GST_LOG_OBJECT (ogg, "Failed pull_range");
+    goto done;
+  }
+
+  ogg->offset += GST_BUFFER_SIZE (buffer);
+
+  if (G_UNLIKELY (ogg->newsegment)) {
+    gst_ogg_demux_send_event (ogg, ogg->newsegment);
+    ogg->newsegment = NULL;
+  }
+
+  ret = gst_ogg_demux_chain (ogg->sinkpad, buffer);
+  if (ret != GST_FLOW_OK) {
+    GST_LOG_OBJECT (ogg, "Failed demux_chain");
+    goto done;
+  }
+
+  /* check for the end of the segment */
+  if (ogg->segment.stop != -1 && ogg->segment.last_stop != -1) {
+    if (ogg->segment.last_stop > ogg->segment.stop) {
+      ret = GST_FLOW_UNEXPECTED;
+      goto done;
+    }
+  }
+done:
+  return ret;
+}
+
+/* reverse mode.
+ *
+ * We read the pages backwards and send the packets forwards. The first packet
+ * in the page will be pushed with the DISCONT flag set.
+ *
+ * Special care has to be taken for continued pages, which we can only decode
+ * when we have the previous page(s).
+ */
+static GstFlowReturn
+gst_ogg_demux_loop_reverse (GstOggDemux * ogg)
+{
+  GstFlowReturn ret;
+  ogg_page page;
+  gint64 offset;
+
+  if (ogg->offset == 0) {
+    GST_LOG_OBJECT (ogg, "no more data to pull %" G_GINT64_FORMAT
+        " == 0", ogg->offset);
+    ret = GST_FLOW_UNEXPECTED;
+    goto done;
+  }
+
+  GST_LOG_OBJECT (ogg, "read page from %" G_GINT64_FORMAT, ogg->offset);
+  ret = gst_ogg_demux_get_prev_page (ogg, &page, &offset);
+  if (ret != GST_FLOW_OK)
+    goto done;
+
+  ogg->offset = offset;
+
+  if (G_UNLIKELY (ogg->newsegment)) {
+    gst_ogg_demux_send_event (ogg, ogg->newsegment);
+    ogg->newsegment = NULL;
+  }
+
+  ret = gst_ogg_demux_handle_page (ogg, &page);
+  if (ret != GST_FLOW_OK)
+    goto done;
+
+  /* check for the end of the segment */
+  if (ogg->segment.start != -1 && ogg->segment.last_stop != -1) {
+    if (ogg->segment.last_stop <= ogg->segment.start) {
+      ret = GST_FLOW_UNEXPECTED;
+      goto done;
+    }
+  }
+done:
+  return ret;
+}
+
+/* random access code
+ *
+ * - first find all the chains and streams by scanning the file.
+ * - then get and chain buffers, just like the streaming case.
+ * - when seeking, we can use the chain info to perform the seek.
+ */
+static void
+gst_ogg_demux_loop (GstOggPad * pad)
+{
+  GstOggDemux *ogg;
+  GstFlowReturn ret;
+  GstEvent *event;
+
+  ogg = GST_OGG_DEMUX (GST_OBJECT_PARENT (pad));
+
+  if (ogg->need_chains) {
+    gboolean res;
+
+    /* this is the only place where we write chains and thus need to lock. */
+    GST_CHAIN_LOCK (ogg);
+    ret = gst_ogg_demux_find_chains (ogg);
+    GST_CHAIN_UNLOCK (ogg);
+    if (ret != GST_FLOW_OK)
+      goto chain_read_failed;
+
+    ogg->need_chains = FALSE;
+
+    GST_OBJECT_LOCK (ogg);
+    ogg->running = TRUE;
+    event = ogg->event;
+    ogg->event = NULL;
+    GST_OBJECT_UNLOCK (ogg);
+
+    /* and seek to configured positions without FLUSH */
+    res = gst_ogg_demux_perform_seek (ogg, event);
+    if (event)
+      gst_event_unref (event);
+
+    if (!res)
+      goto seek_failed;
+  }
+
+  if (ogg->segment.rate >= 0.0)
+    ret = gst_ogg_demux_loop_forward (ogg);
+  else
+    ret = gst_ogg_demux_loop_reverse (ogg);
+
+  if (ret != GST_FLOW_OK)
+    goto pause;
+
+  return;
+
+  /* ERRORS */
+chain_read_failed:
+  {
+    /* error was posted */
+    goto pause;
+  }
+seek_failed:
+  {
+    GST_ELEMENT_ERROR (ogg, STREAM, DEMUX, (NULL),
+        ("failed to start demuxing ogg"));
+    ret = GST_FLOW_ERROR;
+    goto pause;
+  }
+pause:
+  {
+    const gchar *reason = gst_flow_get_name (ret);
+
+    GST_LOG_OBJECT (ogg, "pausing task, reason %s", reason);
+    ogg->segment_running = FALSE;
+    gst_pad_pause_task (ogg->sinkpad);
+
+    if (GST_FLOW_IS_FATAL (ret) || ret == GST_FLOW_NOT_LINKED) {
+      if (ret == GST_FLOW_UNEXPECTED) {
+        /* perform EOS logic */
+        if (ogg->segment.flags & GST_SEEK_FLAG_SEGMENT) {
+          gint64 stop;
+
+          /* for segment playback we need to post when (in stream time)
+           * we stopped, this is either stop (when set) or the duration. */
+          if ((stop = ogg->segment.stop) == -1)
+            stop = ogg->segment.duration;
+
+          GST_LOG_OBJECT (ogg, "Sending segment done, at end of segment");
+          gst_element_post_message (GST_ELEMENT (ogg),
+              gst_message_new_segment_done (GST_OBJECT (ogg), GST_FORMAT_TIME,
+                  stop));
+        } else {
+          /* normal playback, send EOS to all linked pads */
+          GST_LOG_OBJECT (ogg, "Sending EOS, at end of stream");
+          gst_ogg_demux_send_event (ogg, gst_event_new_eos ());
+        }
+      } else {
+        GST_ELEMENT_ERROR (ogg, STREAM, FAILED,
+            (_("Internal data stream error.")),
+            ("stream stopped, reason %s", reason));
+        gst_ogg_demux_send_event (ogg, gst_event_new_eos ());
+      }
+    }
+    return;
+  }
+}
+
+static void
+gst_ogg_demux_clear_chains (GstOggDemux * ogg)
+{
+  gint i;
+
+  gst_ogg_demux_deactivate_current_chain (ogg);
+
+  GST_CHAIN_LOCK (ogg);
+  for (i = 0; i < ogg->chains->len; i++) {
+    GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+
+    gst_ogg_chain_free (chain);
+  }
+  ogg->chains = g_array_set_size (ogg->chains, 0);
+  GST_CHAIN_UNLOCK (ogg);
+}
+
+/* this function is called when the pad is activated and should start
+ * processing data.
+ *
+ * We check if we can do random access to decide if we work push or
+ * pull based.
+ */
+static gboolean
+gst_ogg_demux_sink_activate (GstPad * sinkpad)
+{
+  if (gst_pad_check_pull_range (sinkpad)) {
+    GST_DEBUG_OBJECT (sinkpad, "activating pull");
+    return gst_pad_activate_pull (sinkpad, TRUE);
+  } else {
+    GST_DEBUG_OBJECT (sinkpad, "activating push");
+    return gst_pad_activate_push (sinkpad, TRUE);
+  }
+}
+
+/* this function gets called when we activate ourselves in push mode.
+ * We cannot seek (ourselves) in the stream */
+static gboolean
+gst_ogg_demux_sink_activate_push (GstPad * sinkpad, gboolean active)
+{
+  GstOggDemux *ogg;
+
+  ogg = GST_OGG_DEMUX (GST_OBJECT_PARENT (sinkpad));
+
+  ogg->seekable = FALSE;
+
+  return TRUE;
+}
+
+/* this function gets called when we activate ourselves in pull mode.
+ * We can perform  random access to the resource and we start a task
+ * to start reading */
+static gboolean
+gst_ogg_demux_sink_activate_pull (GstPad * sinkpad, gboolean active)
+{
+  GstOggDemux *ogg;
+
+  ogg = GST_OGG_DEMUX (GST_OBJECT_PARENT (sinkpad));
+
+  if (active) {
+    ogg->need_chains = TRUE;
+    ogg->seekable = TRUE;
+
+    return gst_pad_start_task (sinkpad, (GstTaskFunction) gst_ogg_demux_loop,
+        sinkpad);
+  } else {
+    return gst_pad_stop_task (sinkpad);
+  }
+}
+
+static GstStateChangeReturn
+gst_ogg_demux_change_state (GstElement * element, GstStateChange transition)
+{
+  GstOggDemux *ogg;
+  GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
+
+  ogg = GST_OGG_DEMUX (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      ogg->basetime = 0;
+      ogg->have_fishead = FALSE;
+      ogg_sync_init (&ogg->sync);
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      ogg_sync_reset (&ogg->sync);
+      ogg->current_granule = -1;
+      ogg->running = FALSE;
+      ogg->segment_running = FALSE;
+      gst_segment_init (&ogg->segment, GST_FORMAT_TIME);
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      break;
+    default:
+      break;
+  }
+
+  result = parent_class->change_state (element, transition);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      gst_ogg_demux_clear_chains (ogg);
+      GST_OBJECT_LOCK (ogg);
+      ogg->running = FALSE;
+      ogg->segment_running = FALSE;
+      ogg->have_fishead = FALSE;
+      GST_OBJECT_UNLOCK (ogg);
+      break;
+    case GST_STATE_CHANGE_READY_TO_NULL:
+      ogg_sync_clear (&ogg->sync);
+      break;
+    default:
+      break;
+  }
+  return result;
+}
+
+static GstClockTime
+gst_annodex_granule_to_time (gint64 granulepos, gint64 granulerate_n,
+    gint64 granulerate_d, guint8 granuleshift)
+{
+  gint64 keyindex, keyoffset;
+  gint64 granulerate;
+  GstClockTime res;
+
+  if (granulepos == 0 || granulerate_n == 0 || granulerate_d == 0)
+    return 0;
+
+  if (granuleshift != 0) {
+    keyindex = granulepos >> granuleshift;
+    keyoffset = granulepos - (keyindex << granuleshift);
+    granulepos = keyindex + keyoffset;
+  }
+
+  /* GST_SECOND / (granulerate_n / granulerate_d) */
+  granulerate = gst_util_uint64_scale (GST_SECOND,
+      granulerate_d, granulerate_n);
+  res = gst_util_uint64_scale (granulepos, granulerate, 1);
+  return res;
+}
+
+gboolean
+gst_ogg_demux_plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_ogg_demux_debug, "oggdemux", 0, "ogg demuxer");
+  GST_DEBUG_CATEGORY_INIT (gst_ogg_demux_setup_debug, "oggdemux_setup", 0,
+      "ogg demuxer setup stage when parsing pipeline");
+
+#if ENABLE_NLS
+  GST_DEBUG ("binding text domain %s to locale dir %s", GETTEXT_PACKAGE,
+      LOCALEDIR);
+  bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
+#endif
+
+  return gst_element_register (plugin, "oggdemux", GST_RANK_PRIMARY,
+      GST_TYPE_OGG_DEMUX);
+}
+
+/* prints all info about the element */
+#undef GST_CAT_DEFAULT
+#define GST_CAT_DEFAULT gst_ogg_demux_setup_debug
+
+#ifdef GST_DISABLE_GST_DEBUG
+
+static void
+gst_ogg_print (GstOggDemux * ogg)
+{
+  /* NOP */
+}
+
+#else /* !GST_DISABLE_GST_DEBUG */
+
+static void
+gst_ogg_print (GstOggDemux * ogg)
+{
+  guint j, i;
+
+  GST_INFO_OBJECT (ogg, "%u chains", ogg->chains->len);
+  GST_INFO_OBJECT (ogg, " total time: %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (ogg->total_time));
+
+  for (i = 0; i < ogg->chains->len; i++) {
+    GstOggChain *chain = g_array_index (ogg->chains, GstOggChain *, i);
+
+    GST_INFO_OBJECT (ogg, " chain %d (%u streams):", i, chain->streams->len);
+    GST_INFO_OBJECT (ogg, "  offset: %" G_GINT64_FORMAT " - %" G_GINT64_FORMAT,
+        chain->offset, chain->end_offset);
+    GST_INFO_OBJECT (ogg, "  begin time: %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (chain->begin_time));
+    GST_INFO_OBJECT (ogg, "  total time: %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (chain->total_time));
+    GST_INFO_OBJECT (ogg, "  segment start: %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (chain->segment_start));
+    GST_INFO_OBJECT (ogg, "  segment stop:  %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (chain->segment_stop));
+
+    for (j = 0; j < chain->streams->len; j++) {
+      GstOggPad *stream = g_array_index (chain->streams, GstOggPad *, j);
+
+      GST_INFO_OBJECT (ogg, "  stream %08x:", stream->serialno);
+      GST_INFO_OBJECT (ogg, "   start time:       %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (stream->start_time));
+      GST_INFO_OBJECT (ogg, "   first granulepos: %" G_GINT64_FORMAT,
+          stream->first_granule);
+      GST_INFO_OBJECT (ogg, "   first time:       %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (stream->first_time));
+    }
+  }
+}
+#endif /* GST_DISABLE_GST_DEBUG */