ext/ogg/: Added an ogg muxer.

Original commit message from CVS:
* ext/ogg/gstogg.c: (plugin_init):
* ext/ogg/gstoggdemux.c: (gst_ogg_demux_plugin_init),
(gst_ogg_print):
* ext/ogg/gstoggmux.c: (gst_ogg_mux_get_type),
(gst_ogg_mux_base_init), (gst_ogg_mux_class_init),
(gst_ogg_mux_get_sink_event_masks), (gst_ogg_mux_init),
(gst_ogg_mux_sinkconnect), (gst_ogg_mux_pad_link),
(gst_ogg_mux_pad_unlink), (gst_ogg_mux_request_new_pad),
(gst_ogg_mux_handle_src_event), (gst_ogg_mux_next_buffer),
(gst_ogg_mux_push_page), (gst_ogg_mux_compare_pads),
(gst_ogg_mux_queue_pads), (gst_ogg_mux_loop),
(gst_ogg_mux_get_property), (gst_ogg_mux_set_property),
(gst_ogg_mux_change_state), (gst_ogg_mux_plugin_init):
Added an ogg muxer.
Small typo fixes in the demuxer.

ChangeLog

@@ -1,3 +1,21 @@
+2004-05-10  Wim Taymans  <wim@fluendo.com>
+
+	* ext/ogg/gstogg.c: (plugin_init):
+	* ext/ogg/gstoggdemux.c: (gst_ogg_demux_plugin_init),
+	(gst_ogg_print):
+	* ext/ogg/gstoggmux.c: (gst_ogg_mux_get_type),
+	(gst_ogg_mux_base_init), (gst_ogg_mux_class_init),
+	(gst_ogg_mux_get_sink_event_masks), (gst_ogg_mux_init),
+	(gst_ogg_mux_sinkconnect), (gst_ogg_mux_pad_link),
+	(gst_ogg_mux_pad_unlink), (gst_ogg_mux_request_new_pad),
+	(gst_ogg_mux_handle_src_event), (gst_ogg_mux_next_buffer),
+	(gst_ogg_mux_push_page), (gst_ogg_mux_compare_pads),
+	(gst_ogg_mux_queue_pads), (gst_ogg_mux_loop),
+	(gst_ogg_mux_get_property), (gst_ogg_mux_set_property),
+	(gst_ogg_mux_change_state), (gst_ogg_mux_plugin_init):
+	Added an ogg muxer.
+	Small typo fixes in the demuxer.
+
 2004-05-10  Wim Taymans  <wim@fluendo.com>
 
 	* ext/theora/theoraenc.c: (gst_theora_enc_class_init),

ext/ogg/gstogg.c

@@ -0,0 +1,44 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+
+extern gboolean gst_ogg_demux_plugin_init (GstPlugin * plugin);
+extern gboolean gst_ogg_mux_plugin_init (GstPlugin * plugin);
+
+GST_DEBUG_CATEGORY (vorbisdec_debug);
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  gst_ogg_demux_plugin_init (plugin);
+  gst_ogg_mux_plugin_init (plugin);
+
+  return TRUE;
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "ogg",
+    "ogg stream manipulation (info about ogg: http://xiph.org)",
+    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)

ext/ogg/gstoggdemux.c

@@ -25,7 +25,7 @@
 #include <gst/gst.h>
 #include <ogg/ogg.h>
 /* memcpy - if someone knows a way to get rid of it, please speak up 
- * note: the ogg docs even say you ned this... */
+ * note: the ogg docs even say you need this... */
 #include <string.h>
 
 GST_DEBUG_CATEGORY_STATIC (gst_ogg_demux_debug);
@@ -376,7 +376,8 @@ gst_ogg_demux_src_event (GstPad * pad, GstEvent * event)
 
       GST_OGG_SET_STATE (ogg, GST_OGG_STATE_SEEK);
       FOR_PAD_IN_CURRENT_CHAIN (ogg, pad,
-          pad->flags |= GST_OGG_PAD_NEEDS_DISCONT;);
+          pad->flags |= GST_OGG_PAD_NEEDS_DISCONT;
+          );
       GST_DEBUG_OBJECT (ogg, "initiating seeking to offset %" G_GUINT64_FORMAT,
           offset);
       ogg->seek_pad = cur;
@@ -423,7 +424,8 @@ gst_ogg_demux_handle_event (GstPad * pad, GstEvent * event)
       gst_event_unref (event);
       GST_FLAG_UNSET (ogg, GST_OGG_FLAG_WAIT_FOR_DISCONT);
       FOR_PAD_IN_CURRENT_CHAIN (ogg, pad,
-          pad->flags |= GST_OGG_PAD_NEEDS_DISCONT;);
+          pad->flags |= GST_OGG_PAD_NEEDS_DISCONT;
+          );
       break;
     case GST_EVENT_EOS:
       if (ogg->state == GST_OGG_STATE_SETUP) {
@@ -959,8 +961,8 @@ gst_ogg_type_find (ogg_packet * packet)
   return NULL;
 }
 
-static gboolean
+gboolean
-plugin_init (GstPlugin * plugin)
+gst_ogg_demux_plugin_init (GstPlugin * plugin)
 {
   GST_DEBUG_CATEGORY_INIT (gst_ogg_demux_debug, "oggdemux", 0, "ogg demuxer");
 
@@ -968,14 +970,9 @@ plugin_init (GstPlugin * plugin)
       GST_TYPE_OGG_DEMUX);
 }
 
-GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
-    GST_VERSION_MINOR,
-    "ogg",
-    "ogg stream manipulation (info about ogg: http://xiph.org)",
-    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)
-
 /* prints all info about the element */
-     static void gst_ogg_print (GstOggDemux * ogg)
+static void
+gst_ogg_print (GstOggDemux * ogg)
 {
   guint i;
   GSList *walk;

ext/ogg/gstoggmux.c

@@ -0,0 +1,678 @@
+/* OGG muxer plugin for GStreamer
+ * Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <ogg/ogg.h>
+/* memcpy - if someone knows a way to get rid of it, please speak up 
+ * note: the ogg docs even say you need this... */
+#include <string.h>
+#include <time.h>
+
+GST_DEBUG_CATEGORY_STATIC (gst_ogg_mux_debug);
+#define GST_CAT_DEFAULT gst_ogg_mux_debug
+
+#define GST_TYPE_OGG_MUX (gst_ogg_mux_get_type())
+#define GST_OGG_MUX(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_OGG_MUX, GstOggMux))
+#define GST_OGG_MUX_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_OGG_MUX, GstOggMux))
+#define GST_IS_OGG_MUX(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_OGG_MUX))
+#define GST_IS_OGG_MUX_CLASS(obj) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_OGG_MUX))
+
+typedef struct _GstOggMux GstOggMux;
+typedef struct _GstOggMuxClass GstOggMuxClass;
+
+/* all information needed for one ogg stream */
+typedef struct
+{
+  GstPad *pad;                  /* reference for this pad is held by element we belong to */
+
+  GstBuffer *buffer;            /* the queued buffer for this pad */
+
+  gint serial;
+  ogg_stream_state stream;
+  gint64 packetno;              /* number of next packet */
+  gint64 pageno;                /* number of next page */
+  gboolean eos;
+
+  guint state;                  /* state of the pad */
+}
+GstOggPad;
+
+typedef enum
+{
+  GST_OGG_PAD_STATE_CONTROL = 0,
+  GST_OGG_PAD_STATE_DATA = 1
+}
+GstOggPadState;
+
+struct _GstOggMux
+{
+  GstElement element;
+
+  /* pad */
+  GstPad *srcpad;
+
+  /* sinkpads, a GSList of GstOggPads */
+  GSList *sinkpads;
+
+  /* the pad we are currently pulling from to fill a page */
+  GstOggPad *pulling;
+
+  /* next timestamp for the page */
+  GstClockTime next_ts;
+
+  /* offset in stream */
+  guint64 offset;
+};
+
+typedef enum
+{
+  GST_OGG_FLAG_BOS = GST_ELEMENT_FLAG_LAST,
+  GST_OGG_FLAG_EOS
+}
+GstOggFlag;
+
+struct _GstOggMuxClass
+{
+  GstElementClass parent_class;
+};
+
+/* elementfactory information */
+static GstElementDetails gst_ogg_mux_details = GST_ELEMENT_DETAILS ("ogg muxer",
+    "Codec/Muxer",
+    "mux ogg streams (info about ogg: http://xiph.org)",
+    "Wim Taymans <wim@fluendo.com>");
+
+/* OggMux signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0,
+};
+
+static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/ogg")
+    );
+
+static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink_%d",
+    GST_PAD_SINK,
+    GST_PAD_REQUEST,
+    GST_STATIC_CAPS_ANY         /* we can take anything, really */
+    );
+
+static void gst_ogg_mux_base_init (gpointer g_class);
+static void gst_ogg_mux_class_init (GstOggMuxClass * klass);
+static void gst_ogg_mux_init (GstOggMux * ogg_mux);
+
+static void gst_ogg_mux_loop (GstElement * element);
+static gboolean gst_ogg_mux_handle_src_event (GstPad * pad, GstEvent * event);
+static GstPad *gst_ogg_mux_request_new_pad (GstElement * element,
+    GstPadTemplate * templ, const gchar * name);
+static void gst_ogg_mux_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec);
+static void gst_ogg_mux_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec);
+static GstElementStateReturn gst_ogg_mux_change_state (GstElement * element);
+
+static GstElementClass *parent_class = NULL;
+
+/*static guint gst_ogg_mux_signals[LAST_SIGNAL] = { 0 }; */
+
+GType
+gst_ogg_mux_get_type (void)
+{
+  static GType ogg_mux_type = 0;
+
+  if (!ogg_mux_type) {
+    static const GTypeInfo ogg_mux_info = {
+      sizeof (GstOggMuxClass),
+      gst_ogg_mux_base_init,
+      NULL,
+      (GClassInitFunc) gst_ogg_mux_class_init,
+      NULL,
+      NULL,
+      sizeof (GstOggMux),
+      0,
+      (GInstanceInitFunc) gst_ogg_mux_init,
+    };
+
+    ogg_mux_type =
+        g_type_register_static (GST_TYPE_ELEMENT, "GstOggMux", &ogg_mux_info,
+        0);
+  }
+  return ogg_mux_type;
+}
+
+static void
+gst_ogg_mux_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&src_factory));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&sink_factory));
+
+  gst_element_class_set_details (element_class, &gst_ogg_mux_details);
+}
+
+static void
+gst_ogg_mux_class_init (GstOggMuxClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
+
+  gstelement_class->request_new_pad = gst_ogg_mux_request_new_pad;
+
+  gstelement_class->change_state = gst_ogg_mux_change_state;
+
+  gstelement_class->get_property = gst_ogg_mux_get_property;
+  gstelement_class->set_property = gst_ogg_mux_set_property;
+}
+
+static const GstEventMask *
+gst_ogg_mux_get_sink_event_masks (GstPad * pad)
+{
+  static const GstEventMask gst_ogg_mux_sink_event_masks[] = {
+    {GST_EVENT_EOS, 0},
+    {0,}
+  };
+
+  return gst_ogg_mux_sink_event_masks;
+}
+
+static void
+gst_ogg_mux_init (GstOggMux * ogg_mux)
+{
+  GstElementClass *klass = GST_ELEMENT_GET_CLASS (ogg_mux);
+
+  ogg_mux->srcpad =
+      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
+          "src"), "src");
+  gst_pad_set_event_function (ogg_mux->srcpad, gst_ogg_mux_handle_src_event);
+  gst_element_add_pad (GST_ELEMENT (ogg_mux), ogg_mux->srcpad);
+
+  GST_FLAG_SET (GST_ELEMENT (ogg_mux), GST_ELEMENT_EVENT_AWARE);
+  GST_FLAG_SET (GST_ELEMENT (ogg_mux), GST_OGG_FLAG_BOS);
+
+  /* seed random number generator for creation of serial numbers */
+  srand (time (NULL));
+
+  ogg_mux->sinkpads = NULL;
+  ogg_mux->pulling = NULL;
+
+  gst_element_set_loop_function (GST_ELEMENT (ogg_mux), gst_ogg_mux_loop);
+}
+
+static GstPadLinkReturn
+gst_ogg_mux_sinkconnect (GstPad * pad, const GstCaps * vscaps)
+{
+  GstOggMux *ogg_mux;
+  GstStructure *structure;
+  const gchar *mimetype;
+
+  ogg_mux = GST_OGG_MUX (gst_pad_get_parent (pad));
+
+  GST_DEBUG ("ogg_mux: sinkconnect triggered on %s", gst_pad_get_name (pad));
+
+  structure = gst_caps_get_structure (vscaps, 0);
+  mimetype = gst_structure_get_name (structure);
+
+  return GST_PAD_LINK_OK;
+}
+
+static void
+gst_ogg_mux_pad_link (GstPad * pad, GstPad * peer, gpointer data)
+{
+  //GstOggMux *ogg_mux = GST_OGG_MUX (data);
+  const gchar *padname = gst_pad_get_name (pad);
+
+  GST_DEBUG ("pad '%s' connected", padname);
+}
+
+static void
+gst_ogg_mux_pad_unlink (GstPad * pad, GstPad * peer, gpointer data)
+{
+  //GstOggMux *ogg_mux = GST_OGG_MUX (data);
+  const gchar *padname = gst_pad_get_name (pad);
+
+  GST_DEBUG ("pad '%s' unlinked", padname);
+}
+
+static GstPad *
+gst_ogg_mux_request_new_pad (GstElement * element,
+    GstPadTemplate * templ, const gchar * req_name)
+{
+  GstOggMux *ogg_mux;
+  GstPad *newpad;
+  GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
+
+  g_return_val_if_fail (templ != NULL, NULL);
+
+  if (templ->direction != GST_PAD_SINK) {
+    g_warning ("ogg_mux: request pad that is not a SINK pad\n");
+    return NULL;
+  }
+
+  g_return_val_if_fail (GST_IS_OGG_MUX (element), NULL);
+
+  ogg_mux = GST_OGG_MUX (element);
+
+  if (templ == gst_element_class_get_pad_template (klass, "sink_%d")) {
+    gint serial;
+    gchar *name;
+
+    if (req_name == NULL || strlen (req_name) < 6) {
+      /* no name given when requesting the pad, use random serial number */
+      serial = rand ();
+    } else {
+      /* parse serial number from requested padname */
+      serial = atoi (&req_name[5]);
+    }
+    /* create new pad with the name */
+    name = g_strdup_printf ("sink_%d", serial);
+    newpad = gst_pad_new_from_template (templ, name);
+    g_free (name);
+
+    /* construct our own wrapper data structure for the pad to
+     * keep track of its status */
+    {
+      GstOggPad *oggpad = g_new0 (GstOggPad, 1);
+
+      oggpad->pad = newpad;
+      oggpad->serial = serial;
+      ogg_stream_init (&oggpad->stream, serial);
+      oggpad->packetno = 0;
+      oggpad->pageno = 0;
+      oggpad->eos = FALSE;
+      /* we assume there will be some control data first for this pad */
+      oggpad->state = GST_OGG_PAD_STATE_CONTROL;
+
+      /* save a pointer to our data in the pad */
+      gst_pad_set_element_private (newpad, oggpad);
+      /* store our data for the pad */
+      ogg_mux->sinkpads = g_slist_prepend (ogg_mux->sinkpads, oggpad);
+    }
+  } else {
+    g_warning ("ogg_mux: this is not our template!\n");
+    return NULL;
+  }
+
+  g_signal_connect (newpad, "linked",
+      G_CALLBACK (gst_ogg_mux_pad_link), (gpointer) ogg_mux);
+  g_signal_connect (newpad, "unlinked",
+      G_CALLBACK (gst_ogg_mux_pad_unlink), (gpointer) ogg_mux);
+
+  /* setup some pad functions */
+  gst_pad_set_link_function (newpad, gst_ogg_mux_sinkconnect);
+  gst_pad_set_event_mask_function (newpad, gst_ogg_mux_get_sink_event_masks);
+  /* dd the pad to the element */
+  gst_element_add_pad (element, newpad);
+
+  return newpad;
+}
+
+/* handle events */
+static gboolean
+gst_ogg_mux_handle_src_event (GstPad * pad, GstEvent * event)
+{
+  GstOggMux *ogg_mux;
+  GstEventType type;
+
+  ogg_mux = GST_OGG_MUX (gst_pad_get_parent (pad));
+
+  type = event ? GST_EVENT_TYPE (event) : GST_EVENT_UNKNOWN;
+
+  switch (type) {
+    case GST_EVENT_SEEK:
+      /* disable seeking for now */
+      return FALSE;
+    default:
+      break;
+  }
+
+  return gst_pad_event_default (pad, event);
+}
+
+static GstBuffer *
+gst_ogg_mux_next_buffer (GstOggPad * pad)
+{
+  GstData *data = NULL;
+
+  while (data == NULL) {
+    GST_LOG ("muxer: pulling %s:%s\n", GST_DEBUG_PAD_NAME (pad->pad));
+    data = gst_pad_pull (pad->pad);
+    /* if it's an event, handle it */
+    if (GST_IS_EVENT (data)) {
+      GstEventType type;
+      GstOggMux *ogg_mux;
+      GstEvent *event = GST_EVENT (data);
+
+      ogg_mux = GST_OGG_MUX (gst_pad_get_parent (pad->pad));
+      type = event ? GST_EVENT_TYPE (event) : GST_EVENT_UNKNOWN;
+
+      switch (type) {
+        case GST_EVENT_EOS:
+          return NULL;
+        default:
+          gst_pad_event_default (pad->pad, event);
+          break;
+      }
+      data = NULL;
+    }
+  }
+  return GST_BUFFER (data);
+}
+
+static void
+gst_ogg_mux_push_page (GstOggMux * mux, ogg_page * page)
+{
+  GstBuffer *buffer;
+
+  /* allocate space for header and body */
+  buffer = gst_pad_alloc_buffer (mux->srcpad, GST_BUFFER_OFFSET_NONE,
+      page->header_len + page->body_len);
+  memcpy (GST_BUFFER_DATA (buffer), page->header, page->header_len);
+  memcpy (GST_BUFFER_DATA (buffer) + page->header_len,
+      page->body, page->body_len);
+
+  /* next_ts was the timestamp of the first buffer put in this page */
+  GST_BUFFER_TIMESTAMP (buffer) = mux->next_ts;
+  GST_BUFFER_OFFSET (buffer) = mux->offset;
+  mux->offset += GST_BUFFER_SIZE (buffer);
+  GST_BUFFER_OFFSET_END (buffer) = mux->offset;
+
+  if (GST_PAD_IS_USABLE (mux->srcpad))
+    gst_pad_push (mux->srcpad, GST_DATA (buffer));
+  else
+    gst_buffer_unref (buffer);
+}
+
+/*
+ * Given two pads, compare the buffers queued on it and return 0 if they have
+ * an equal priority, 1 if the new pad is better, -1 if the old pad is better 
+ */
+static gint
+gst_ogg_mux_compare_pads (GstOggMux * ogg_mux, GstOggPad * old, GstOggPad * new)
+{
+  guint64 oldtime, newtime;
+
+  /* if the old pad doesn't contain anything or is even NULL, return 
+   * the new pad as best candidate and vice versa */
+  if (old == NULL || old->buffer == NULL)
+    return 1;
+  if (new == NULL || new->buffer == NULL)
+    return -1;
+
+  /* no timestamp on old buffer, it must go first */
+  oldtime = GST_BUFFER_TIMESTAMP (old->buffer);
+  if (oldtime == GST_CLOCK_TIME_NONE)
+    return -1;
+
+  /* no timestamp on new buffer, it must go first */
+  newtime = GST_BUFFER_TIMESTAMP (new->buffer);
+  if (newtime == GST_CLOCK_TIME_NONE)
+    return 1;
+
+  /* old buffer has higher timestamp, new one should go first */
+  if (newtime < oldtime)
+    return 1;
+  /* new buffer has higher timestamp, old one should go first */
+  else if (newtime > oldtime)
+    return -1;
+  else {
+    /* buffers with equal timestamps, prefer the pad that has the
+     * least number of pages muxed */
+    if (new->pageno < old->pageno)
+      return 1;
+    else if (new->pageno > old->pageno)
+      return -1;
+  }
+
+  /* same priority if all of the above failed */
+  return 0;
+}
+
+/* make sure a buffer is queued on all pads, returns a pointer to an oggpad
+ * that holds the best buffer or NULL when no pad was usable */
+static GstOggPad *
+gst_ogg_mux_queue_pads (GstOggMux * ogg_mux)
+{
+  GstOggPad *bestpad = NULL;
+  GSList *walk;
+
+  /* try to make sure we have a buffer from each usable pad first */
+  walk = ogg_mux->sinkpads;
+  while (walk) {
+    GstOggPad *pad = (GstOggPad *) walk->data;
+
+    walk = walk->next;
+
+    /* try to get a new buffer for this pad if needed and possible */
+    if (pad->buffer == NULL && GST_PAD_IS_USABLE (pad->pad)) {
+      pad->buffer = gst_ogg_mux_next_buffer (pad);
+      /* no next buffer, try another pad */
+      if (pad->buffer == NULL)
+        continue;
+    }
+
+    /* skip unusable pads */
+    if (!GST_PAD_IS_USABLE (pad->pad))
+      continue;
+
+    /* we should have a buffer now, see if it is the best pad to
+     * pull on */
+    if (pad->buffer != NULL) {
+      if (gst_ogg_mux_compare_pads (ogg_mux, bestpad, pad) > 0) {
+        bestpad = pad;
+      }
+    }
+  }
+  return bestpad;
+}
+
+/* basic idea:
+ *
+ * 1) find a pad to pull on, this is done by pulling on all pads and
+ *    looking at the buffers to decide which one should be muxed first.
+ * 2) store the selected pad and keep on pulling until we fill a 
+ *    complete ogg page. This is needed because the ogg spec says that
+ *    you should fill a complete page with data from the same logical
+ *    stream. When the page is filled, go back to 1).
+ * 3) before filling a packet, read ahead one more buffer to see if this
+ *    packet is the last of the stream.
+ */
+static void
+gst_ogg_mux_loop (GstElement * element)
+{
+  GstOggMux *ogg_mux;
+
+  ogg_mux = GST_OGG_MUX (element);
+
+  /* if we don't know which pad to pull on, find one */
+  if (ogg_mux->pulling == NULL) {
+    ogg_mux->pulling = gst_ogg_mux_queue_pads (ogg_mux);
+    /* remember timestamp of first buffer for this new pad */
+    if (ogg_mux->pulling != NULL) {
+      ogg_mux->next_ts = GST_BUFFER_TIMESTAMP (ogg_mux->pulling->buffer);
+    } else {
+      /* no pad to pull on, send EOS */
+      if (GST_PAD_IS_USABLE (ogg_mux->srcpad))
+        gst_pad_push (ogg_mux->srcpad,
+            GST_DATA (gst_event_new (GST_EVENT_EOS)));
+      gst_element_set_eos (element);
+      return;
+    }
+  }
+
+  /* we are pulling from a pad, continue to do so until a page
+   * has been filled and pushed */
+  if (ogg_mux->pulling != NULL) {
+    ogg_packet packet;
+    ogg_page page;
+    GstBuffer *buf, *tmpbuf;
+    GstOggPad *pad = ogg_mux->pulling;
+    gint ret;
+    GstOggPadState newstate;
+
+    /* now see if we have a buffer */
+    buf = pad->buffer;
+    if (buf == NULL) {
+      /* no buffer, get one */
+      buf = gst_ogg_mux_next_buffer (pad);
+      /* data exhausted on this pad (EOS) */
+      if (buf == NULL) {
+        /* stop pulling from the pad */
+        ogg_mux->pulling = NULL;
+        return;
+      }
+    }
+
+    /* ogg expects headers and data to be in a different page, we
+     * have no way of knowing headers from data here so we use the
+     * buffer control flag as a hint */
+    newstate = (pad->packetno < 3 ?
+        GST_OGG_PAD_STATE_CONTROL : GST_OGG_PAD_STATE_DATA);
+
+    if (newstate != pad->state) {
+      /* state switch, flush page */
+      while (ogg_stream_flush (&pad->stream, &page)) {
+        gst_ogg_mux_push_page (ogg_mux, &page);
+        pad->pageno++;
+      }
+      /* switching state */
+      pad->state = newstate;
+    }
+
+    /* create a packet from the buffer */
+    packet.packet = GST_BUFFER_DATA (buf);
+    packet.bytes = GST_BUFFER_SIZE (buf);
+    packet.granulepos = GST_BUFFER_OFFSET_END (buf);
+    /* mark BOS and packet number */
+    packet.b_o_s = (pad->packetno == 0);
+    packet.packetno = pad->packetno++;
+
+    /* read ahead one more buffer to find EOS */
+    tmpbuf = gst_ogg_mux_next_buffer (pad);
+    /* data exhausted on this pad */
+    if (tmpbuf == NULL) {
+      /* stop pulling from the pad */
+      ogg_mux->pulling = NULL;
+    }
+    /* mark EOS */
+    packet.e_o_s = (tmpbuf == NULL ? 1 : 0);
+
+    /* swap the packet in */
+    ogg_stream_packetin (&pad->stream, &packet);
+
+    /* don't need the old buffer anymore */
+    gst_buffer_unref (pad->buffer);
+    /* store new readahead buffer */
+    pad->buffer = tmpbuf;
+
+    /* create a page */
+    ret = ogg_stream_pageout (&pad->stream, &page);
+    if (ret > 0) {
+      /* we have a complete page now, we can push the page 
+       * and make sure to pull on a new pad the next time around */
+      gst_ogg_mux_push_page (ogg_mux, &page);
+      /* increment the page number counter */
+      pad->pageno++;
+      /* we're done pulling on this pad, make sure to choose a new 
+       * pad for pulling in the next iteration */
+      ogg_mux->pulling = NULL;
+    }
+  }
+}
+
+static void
+gst_ogg_mux_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec)
+{
+  switch (prop_id) {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_ogg_mux_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec)
+{
+  switch (prop_id) {
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static GstElementStateReturn
+gst_ogg_mux_change_state (GstElement * element)
+{
+  GstOggMux *ogg_mux;
+  gint transition = GST_STATE_TRANSITION (element);
+
+  g_return_val_if_fail (GST_IS_OGG_MUX (element), GST_STATE_FAILURE);
+
+  ogg_mux = GST_OGG_MUX (element);
+
+  switch (transition) {
+    case GST_STATE_NULL_TO_READY:
+    case GST_STATE_READY_TO_PAUSED:
+      ogg_mux->next_ts = 0;
+      ogg_mux->offset = 0;
+      ogg_mux->pulling = NULL;
+      break;
+    case GST_STATE_PAUSED_TO_PLAYING:
+    case GST_STATE_PLAYING_TO_PAUSED:
+    case GST_STATE_PAUSED_TO_READY:
+    case GST_STATE_READY_TO_NULL:
+      break;
+  }
+
+  if (GST_ELEMENT_CLASS (parent_class)->change_state)
+    return GST_ELEMENT_CLASS (parent_class)->change_state (element);
+
+  return GST_STATE_SUCCESS;
+}
+
+gboolean
+gst_ogg_mux_plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_ogg_mux_debug, "oggmux", 0, "ogg muxer");
+
+  return gst_element_register (plugin, "oggmux", GST_RANK_PRIMARY,
+      GST_TYPE_OGG_MUX);
+}