Index: libs/gst/base/gstbaseparse.c
===================================================================
--- libs/gst/base/gstbaseparse.c	(revision 0)
+++ libs/gst/base/gstbaseparse.c	(revision 6859)
@@ -0,0 +1,1438 @@
+/* GStreamer
+ * Copyright (C) 2008 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Stefan Kost <stefan.kost@nokia.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.
+ */
+
+/**
+ * SECTION:gstbaseparse
+ * @short_description: Base class for stream parsers
+ * @see_also: #GstBaseTransform
+ *
+ * This base class is for parser elements that process data and splits it 
+ * into separate audio/video/whatever frames.
+ *
+ * It provides for:
+ * <itemizedlist>
+ *   <listitem><para>One sinkpad and one srcpad</para></listitem>
+ *   <listitem><para>Handles state changes</para></listitem>
+ *   <listitem><para>Does flushing</para></listitem>
+ *   <listitem><para>Push mode</para></listitem>
+ *   <listitem><para>Pull mode</para></listitem>
+ *   <listitem><para>Handles events (NEWSEGMENT/EOS/FLUSH)</para></listitem>
+ *   <listitem><para>Handles seeking in both modes</para></listitem>
+ *   <listitem><para>
+ *        Handles POSITION/DURATION/SEEKING/FORMAT/CONVERT queries
+ *   </para></listitem>
+ * </itemizedlist>
+ *
+ * The purpose of this base class is to provide a basic functionality of
+ * a parser and share a lot of rather complex code.
+ *
+ * Description of the parsing mechanism:
+ * <orderedlist>
+ * <listitem>
+ *   <itemizedlist><title>Set-up phase</title>
+ *   <listitem><para>
+ *     GstBaseParse class calls @set_sink_caps to inform the subclass about
+ *     incoming sinkpad caps. Subclass should set the srcpad caps accordingly.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     GstBaseParse calls @start to inform subclass that data processing is
+ *     about to start now.
+ *   </para></listitem>
+ *   <listitem><para>
+ *      At least in this point subclass needs to tell the GstBaseParse class
+ *      how big data chunks it wants to receive (min_frame_size). It can do 
+ *      this with @gst_base_parse_set_min_frame_size.
+ *   </para></listitem>
+ *   <listitem><para>
+ *      GstBaseParse class sets up appropriate data passing mode (pull/push)
+ *      and starts to process the data.
+ *   </para></listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * <listitem>
+ *   <itemizedlist>
+ *   <title>Parsing phase</title>
+ *     <listitem><para>
+ *       GstBaseParse gathers at least min_frame_size bytes of data either 
+ *       by pulling it from upstream or collecting buffers into internal
+ *       #GstAdapter.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       A buffer of min_frame_size bytes is passed to subclass with
+ *       @check_valid_frame. Subclass checks the contents and returns TRUE
+ *       if the buffer contains a valid frame. It also needs to set the
+ *       @framesize according to the detected frame size. If buffer didn't
+ *       contain a valid frame, this call should must FALSE and optionally
+ *       set the @skipsize value to inform base class that how many bytes
+ *       it needs to skip in order to find a valid frame.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       After valid frame is found, it will be passed again to subclass with
+ *       @parse_frame call. Now subclass is responsible for parsing the
+ *       frame contents and setting the buffer timestamp, duration and caps.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       Finally the buffer can be pushed downstream and parsing loop starts
+ *       over again.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       During the parsing process GstBaseClass will handle both srcpad and
+ *       sinkpad events. They will be passed to subclass if @event or
+ *       @src_event callbacks have been provided.
+ *     </para></listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * <listitem>
+ *   <itemizedlist><title>Shutdown phase</title>
+ *   <listitem><para>
+ *     GstBaseParse class calls @stop to inform the subclass that data
+ *     parsing will be stopped.
+ *   </para></listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * </orderedlist>
+ *
+ * Subclass is responsible for providing pad template caps for
+ * source and sink pads. The pads need to be named "sink" and "src". It also 
+ * needs to set the fixed caps on srcpad, when the format is ensured (e.g. 
+ * when base class calls subclass' @set_sink_caps function).
+ *
+ * This base class uses GST_FORMAT_DEFAULT as a meaning of frames. So,
+ * subclass conversion routine needs to know that conversion from
+ * GST_FORMAT_TIME to GST_FORMAT_DEFAULT must return the
+ * frame number that can be found from the given byte position.
+ *
+ * GstBaseParse uses subclasses conversion methods also for seeking. If
+ * subclass doesn't provide @convert function, seeking will get disabled.
+ *
+ * Subclass @start and @stop functions will be called to inform the beginning
+ * and end of data processing.
+ *
+ * Things that subclass need to take care of:
+ * <itemizedlist>
+ *   <listitem><para>Provide pad templates</para></listitem>
+ *   <listitem><para>
+ *      Fixate the source pad caps when appropriate
+ *   </para></listitem>
+ *   <listitem><para>
+ *      Inform base class how big data chunks should be retrieved. This is
+ *      done with @gst_base_parse_set_min_frame_size function.
+ *   </para></listitem>
+ *   <listitem><para>
+ *      Examine data chunks passed to subclass with @check_valid_frame
+ *      and tell if they contain a valid frame
+ *   </para></listitem>
+ *   <listitem><para>
+ *      Set the caps and timestamp to frame that is passed to subclass with
+ *      @parse_frame function.
+ *   </para></listitem>
+ *   <listitem><para>Provide conversion functions</para></listitem>
+ *   <listitem><para>
+ *      Update the duration information with @gst_base_parse_set_duration
+ *   </para></listitem>
+ * </itemizedlist>
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "../../../gst/gst_private.h"
+#include "../../../gst/gst-i18n-lib.h"
+#include "gstbaseparse.h"
+#include <gst/gstmarshal.h>
+
+GST_DEBUG_CATEGORY_STATIC (gst_base_parse_debug);
+#define GST_CAT_DEFAULT gst_base_parse_debug
+
+
+/* Supported formats */
+static GstFormat fmtlist[] = {
+  GST_FORMAT_DEFAULT,
+  GST_FORMAT_BYTES,
+  GST_FORMAT_TIME,
+  0
+};
+
+#define GST_BASE_PARSE_GET_PRIVATE(obj)  \
+    (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BASE_PARSE, GstBaseParsePrivate))
+
+struct _GstBaseParsePrivate
+{
+  GstActivateMode pad_mode;
+  gint64 duration;
+  GstFormat duration_fmt;
+  guint min_frame_size;
+  gboolean discont;
+  gboolean flushing;
+  gint64 offset;
+  gint64 pending_offset;
+};
+
+static GstElementClass *parent_class = NULL;
+
+static void gst_base_parse_base_init (gpointer g_class);
+static void gst_base_parse_class_init (GstBaseParseClass * klass);
+static void gst_base_parse_init (GstBaseParse * parse,
+    GstBaseParseClass * klass);
+
+GType
+gst_base_parse_get_type (void)
+{
+  static GType base_parse_type = 0;
+
+  if (!base_parse_type) {
+    static const GTypeInfo base_parse_info = {
+      sizeof (GstBaseParseClass),
+      (GBaseInitFunc) gst_base_parse_base_init,
+      NULL,
+      (GClassInitFunc) gst_base_parse_class_init,
+      NULL,
+      NULL,
+      sizeof (GstBaseParse),
+      0,
+      (GInstanceInitFunc) gst_base_parse_init,
+    };
+
+    base_parse_type = g_type_register_static (GST_TYPE_ELEMENT,
+        "GstBaseParse", &base_parse_info, G_TYPE_FLAG_ABSTRACT);
+  }
+  return base_parse_type;
+}
+
+static void gst_base_parse_finalize (GObject * object);
+
+static gboolean gst_base_parse_sink_activate (GstPad * sinkpad);
+static gboolean gst_base_parse_sink_activate_push (GstPad * pad,
+    gboolean active);
+static gboolean gst_base_parse_sink_activate_pull (GstPad * pad,
+    gboolean active);
+static gboolean gst_base_parse_handle_seek (GstBaseParse * parse,
+    GstEvent * event);
+
+static gboolean gst_base_parse_src_event (GstPad * pad, GstEvent * event);
+static gboolean gst_base_parse_sink_event (GstPad * pad, GstEvent * event);
+static gboolean gst_base_parse_query (GstPad * pad, GstQuery * query);
+static gboolean gst_base_parse_sink_setcaps (GstPad * pad, GstCaps * caps);
+static const GstQueryType * gst_base_parse_get_querytypes (GstPad * pad);
+
+static GstFlowReturn gst_base_parse_chain (GstPad * pad, GstBuffer * buffer);
+static void gst_base_parse_loop (GstPad * pad);
+
+static gboolean gst_base_parse_check_frame (GstBaseParse *parse,
+    GstBuffer *buffer, guint *framesize, guint *skipsize);
+
+static gboolean gst_base_parse_parse_frame (GstBaseParse *parse,
+    GstBuffer *buffer);
+
+static gboolean gst_base_parse_sink_eventfunc (GstBaseParse * parse,
+    GstEvent * event);
+
+static gboolean gst_base_parse_src_eventfunc (GstBaseParse * parse,
+    GstEvent * event);
+
+
+static void
+gst_base_parse_base_init (gpointer g_class)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_base_parse_debug, "baseparse", 0,
+      "baseparse element");
+}
+
+static void
+gst_base_parse_finalize (GObject * object)
+{
+  GstBaseParse *parse;
+
+  parse = GST_BASE_PARSE (object);
+  g_mutex_free (parse->parse_lock);
+  gst_adapter_clear (parse->adapter);
+  g_object_unref (parse->adapter);
+
+  if (parse->pending_segment) {
+    GstEvent **eventp = &parse->pending_segment;
+    gst_event_replace (eventp, NULL);
+  }
+  if (parse->close_segment) {
+    GstEvent **eventp = &parse->close_segment;
+    gst_event_replace (eventp, NULL);
+  }
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_base_parse_class_init (GstBaseParseClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+  g_type_class_add_private (klass, sizeof (GstBaseParsePrivate));
+  parent_class = g_type_class_peek_parent (klass);
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_base_parse_finalize);
+
+  /* Default handlers */
+  klass->check_valid_frame = gst_base_parse_check_frame;
+  klass->parse_frame = gst_base_parse_parse_frame;
+  klass->event = gst_base_parse_sink_eventfunc;
+  klass->src_event = gst_base_parse_src_eventfunc;
+}
+
+static void
+gst_base_parse_init (GstBaseParse * parse,
+    GstBaseParseClass * bclass)
+{
+  GstPadTemplate *pad_template;
+
+  GST_DEBUG ("gst_base_parse_init");
+
+  parse->priv = GST_BASE_PARSE_GET_PRIVATE (parse);
+
+  pad_template =
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (bclass), "sink");
+  g_return_if_fail (pad_template != NULL);
+  parse->sinkpad = gst_pad_new_from_template (pad_template, "sink");
+  gst_pad_set_event_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_sink_event));
+  gst_pad_set_setcaps_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_sink_setcaps));
+  gst_pad_set_chain_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_chain));
+  gst_pad_set_activate_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_sink_activate));
+  gst_pad_set_activatepush_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_sink_activate_push));
+  gst_pad_set_activatepull_function (parse->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_sink_activate_pull));
+  gst_element_add_pad (GST_ELEMENT (parse), parse->sinkpad);
+
+  GST_DEBUG ("sinkpad created");
+
+  pad_template =
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (bclass), "src");
+  g_return_if_fail (pad_template != NULL);
+  parse->srcpad = gst_pad_new_from_template (pad_template, "src");
+  gst_pad_set_event_function (parse->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_src_event));
+  gst_pad_set_query_type_function (parse->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_get_querytypes));
+  gst_pad_set_query_function (parse->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_parse_query));
+  gst_element_add_pad (GST_ELEMENT (parse), parse->srcpad);
+  GST_DEBUG ("src created");
+
+  parse->parse_lock = g_mutex_new ();
+  parse->adapter = gst_adapter_new ();
+  parse->pending_segment = NULL;
+  parse->close_segment = NULL;
+
+  parse->priv->pad_mode = GST_ACTIVATE_NONE;
+  parse->priv->duration = -1;
+  parse->priv->min_frame_size = 1;
+  parse->priv->discont = FALSE;
+  parse->priv->flushing = FALSE;
+  parse->priv->offset = 0;
+  GST_DEBUG ("init ok");
+}
+
+
+
+/**
+ * gst_base_parse_check_frame:
+ * @parse: #GstBaseParse.
+ * @buffer: GstBuffer.
+ * @framesize:
+ * @skipsize:
+ *
+ * Default callback for check_valid_frame.
+ * 
+ * Returns: Always TRUE.
+ */
+static gboolean
+gst_base_parse_check_frame (GstBaseParse *parse,
+                            GstBuffer *buffer,
+                            guint *framesize,
+                            guint *skipsize)
+{
+  *framesize = GST_BUFFER_SIZE (buffer);
+  *skipsize = 0;
+  return TRUE;
+}
+
+
+/**
+ * gst_base_parse_parse_frame:
+ * @parse: #GstBaseParse
+ * @buffer: #GstBuffer
+ *
+ */
+static gboolean
+gst_base_parse_parse_frame (GstBaseParse *parse, GstBuffer *buffer)
+{
+  /* FIXME: Could we even _try_ to do something clever here? */
+  GST_BUFFER_TIMESTAMP (buffer) = GST_CLOCK_TIME_NONE;
+  GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
+  gst_buffer_set_caps (buffer, GST_PAD_CAPS (parse->srcpad));
+  return TRUE;
+}
+
+
+/**
+ * gst_base_parse_bytepos_to_time:
+ * @parse: #GstBaseParse.
+ * @bytepos: Position (in bytes) to be converted.
+ * @pos_in_time: #GstClockTime pointer where the result is set.
+ *
+ * Convert given byte position into #GstClockTime format.
+ * 
+ * Returns: TRUE if conversion succeeded.
+ */
+static gboolean
+gst_base_parse_bytepos_to_time (GstBaseParse *parse, gint64 bytepos,
+                                GstClockTime *pos_in_time)
+{
+  GstBaseParseClass *klass;
+  gboolean res = FALSE;
+
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  if (klass->convert) {
+    res = klass->convert (parse, GST_FORMAT_BYTES, bytepos,
+                          GST_FORMAT_TIME, pos_in_time);
+  }
+  return res;
+}
+
+
+/**
+ * gst_base_parse_sink_event:
+ * @pad: #GstPad.
+ * @event: #GstEvent.
+ *
+ * Handler for sink pad events.
+ *
+ * Returns: TRUE if the event was handled.
+ */
+static gboolean
+gst_base_parse_sink_event (GstPad * pad, GstEvent * event)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *bclass;
+  gboolean handled = FALSE;
+  gboolean ret = TRUE;
+
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  bclass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  GST_DEBUG ("handling event %d", GST_EVENT_TYPE (event));
+
+  if (bclass->event)
+    handled = bclass->event (parse, event);
+
+  if (!handled)
+    ret = gst_pad_push_event (parse->srcpad, event);
+
+  gst_object_unref (parse);
+  GST_DEBUG ("event handled");
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_sink_eventfunc:
+ * @parse: #GstBaseParse.
+ * @event: #GstEvent.
+ *
+ * Returns: TRUE if the event was handled and not need forwarding.
+ */
+static gboolean
+gst_base_parse_sink_eventfunc (GstBaseParse * parse, GstEvent * event)
+{
+  gboolean handled = FALSE;
+  GstEvent **eventp;
+
+  switch (GST_EVENT_TYPE (event))
+  {
+    case GST_EVENT_NEWSEGMENT:
+    {
+      gdouble rate, applied_rate;
+      GstFormat format;
+      gint64 start, stop, pos;
+      gboolean update;
+
+      gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
+                                        &format, &start, &stop, &pos);
+
+
+      if (format == GST_FORMAT_BYTES) {
+        GstClockTime seg_start, seg_stop, seg_pos;
+
+        /* stop time is allowed to be open-ended, but not start & pos */
+        seg_stop = GST_CLOCK_TIME_NONE;
+        parse->priv->pending_offset = pos;
+
+        if (gst_base_parse_bytepos_to_time (parse, start, &seg_start) &&
+            gst_base_parse_bytepos_to_time (parse, pos, &seg_pos))
+        {
+          gst_event_unref (event);
+          event = gst_event_new_new_segment_full (update, rate, applied_rate,
+              GST_FORMAT_TIME, seg_start, seg_stop, seg_pos);
+          format = GST_FORMAT_TIME;
+          GST_DEBUG_OBJECT (parse, "Converted incoming segment to TIME. "
+              "start = %" GST_TIME_FORMAT ", stop = %" GST_TIME_FORMAT
+                  ", pos = %" GST_TIME_FORMAT, GST_TIME_ARGS (seg_start),
+                  GST_TIME_ARGS (seg_stop), GST_TIME_ARGS (seg_pos));
+        }
+      }
+
+      if (format != GST_FORMAT_TIME) {
+        /* Unknown incoming segment format. Output a default open-ended 
+        * TIME segment */
+        gst_event_unref (event);
+        event = gst_event_new_new_segment_full (update, rate, applied_rate,
+            GST_FORMAT_TIME, 0, GST_CLOCK_TIME_NONE, 0);
+      }
+
+      gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
+                                        &format, &start, &stop, &pos);
+
+      gst_segment_set_newsegment_full (&parse->segment, update, rate,
+                                       applied_rate, format, start, stop, pos);
+
+      GST_DEBUG_OBJECT (parse, "Created newseg rate %g, applied rate %g, "
+          "format %d, start = %" GST_TIME_FORMAT ", stop = %" GST_TIME_FORMAT
+          ", pos = %" GST_TIME_FORMAT, rate, applied_rate, format,
+          GST_TIME_ARGS (start), GST_TIME_ARGS (stop), GST_TIME_ARGS (pos));
+
+      /* save the segment for later, right before we push a new buffer so that
+       * the caps are fixed and the next linked element can receive
+       * the segment. */
+      eventp = &parse->pending_segment;
+      gst_event_replace (eventp, event);
+      gst_event_unref (event);
+      handled = TRUE;
+      break;
+    }
+
+    case GST_EVENT_FLUSH_START:
+      parse->priv->flushing = TRUE;
+      /* Wait for _chain() to exit by taking the srcpad STREAM_LOCK */
+      GST_PAD_STREAM_LOCK (parse->srcpad);
+      handled = gst_pad_push_event (parse->srcpad, event);
+      GST_PAD_STREAM_UNLOCK (parse->srcpad);
+      break;
+
+    case GST_EVENT_FLUSH_STOP:
+      gst_adapter_clear (parse->adapter);
+      parse->priv->flushing = FALSE;
+      parse->priv->discont = TRUE;
+      break;
+
+    default:
+      break;
+  }
+
+  return handled;
+}
+
+
+/**
+ * gst_base_parse_src_event:
+ * @pad: #GstPad.
+ * @event: #GstEvent.
+ *
+ * Handler for source pad events.
+ *
+ * Returns: TRUE if the event was handled.
+ */
+static gboolean
+gst_base_parse_src_event (GstPad * pad, GstEvent * event)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *bclass;
+  gboolean handled = FALSE;
+  gboolean ret = TRUE;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  bclass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  GST_DEBUG ("event %d, %s", GST_EVENT_TYPE (event),
+             GST_EVENT_TYPE_NAME (event));
+
+  if (bclass->src_event)
+    handled = bclass->src_event (parse, event);
+
+  if (!handled)
+    ret = gst_pad_push_event (parse->sinkpad, event);
+
+  gst_object_unref (parse);
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_src_eventfunc:
+ * @parse: #GstBaseParse.
+ * @event: #GstEvent
+ *
+ * Returns: TRUE if the event was handled and can be dropped.
+ */
+static gboolean
+gst_base_parse_src_eventfunc (GstBaseParse * parse, GstEvent * event)
+{
+  gboolean handled = FALSE;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+    {
+      handled = gst_base_parse_handle_seek (parse, event);
+      gst_event_unref (event);
+      break;
+    }
+    default:
+      break;
+  }
+  return handled;
+}
+
+
+/**
+ * gst_base_parse_handle_and_push_buffer:
+ * @parse: #GstBaseParse.
+ * @klass: #GstBaseParseClass.
+ * @buffer: #GstBuffer.
+ *
+ * Returns: #GstFlowReturn
+ */
+static GstFlowReturn
+gst_base_parse_handle_and_push_buffer (GstBaseParse *parse,
+                                       GstBaseParseClass *klass,
+                                       GstBuffer *buffer)
+{
+  GstFlowReturn ret;
+
+  if (parse->priv->discont) {
+    GST_DEBUG_OBJECT (parse, "marking DISCONT");
+    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+    parse->priv->discont = FALSE;
+  }
+
+  ret = klass->parse_frame (parse, buffer);
+
+  /* FIXME. Check the output buffer for any missing metadata */
+
+  if (ret == GST_FLOW_OK) {
+    ret = gst_pad_push (parse->srcpad, buffer);
+    GST_LOG ("frame pushed: %d", ret);
+  }
+  else {
+    gst_buffer_unref (buffer);
+  }
+
+  /* convert internal flow to OK and mark discont for the next buffer. */
+  if (ret == GST_BASE_PARSE_FLOW_DROPPED) {
+    parse->priv->discont = TRUE;
+    ret = GST_FLOW_OK;
+  }
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_chain:
+ * @pad: #GstPad.
+ * @buffer: #GstBuffer.
+ *
+ * Returns: #GstFlowReturn.
+ */
+static GstFlowReturn
+gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstBaseParseClass *bclass;
+  GstBaseParse *parse;
+  GstFlowReturn ret = GST_FLOW_OK;
+  GstBuffer *outbuf = NULL;
+  GstBuffer *tmpbuf = NULL;
+  guint fsize = 0, skip = 0;
+  const guint8 *data;
+  guint min_size;
+
+  parse = GST_BASE_PARSE (GST_OBJECT_PARENT (pad));
+  bclass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  GST_LOG ("buffer size: %d, offset = %lld",
+           GST_BUFFER_SIZE(buffer), GST_BUFFER_OFFSET (buffer));
+
+
+  if (parse->pending_segment) {
+    GST_DEBUG ("chain pushing a pending segment");
+    gst_pad_push_event (parse->srcpad, parse->pending_segment);
+    parse->pending_segment = NULL;
+    parse->priv->offset = parse->priv->pending_offset;
+
+    /* Make sure that adapter doesn't have any old data after
+       newsegment has been pushed */
+
+    /* FIXME: when non-flushing seek occurs, chain is still processing the
+       data from old segment. If this processing loop is then interrupted
+       (e.g. paused), chain function exists and next time it gets called
+       all this old data gets lost and playback continues from new segment */
+    gst_adapter_clear (parse->adapter);
+  }
+
+  gst_adapter_push (parse->adapter, buffer);
+
+  GST_BASE_PARSE_LOCK (parse);
+  min_size = parse->priv->min_frame_size;
+  GST_BASE_PARSE_UNLOCK (parse);
+
+  /* Parse and push as many frames as possible */
+  /* Stop either when adapter is empty or we are flushing */
+  while (!parse->priv->flushing) {
+
+    /* Synchronization loop */
+    for (;;) {
+      /* Collect at least min_frame_size bytes */
+      if (gst_adapter_available (parse->adapter) < min_size)
+      {
+        GST_DEBUG ("not enough data available (only %d bytes)",
+                   gst_adapter_available (parse->adapter));
+        goto done;
+      }
+
+      data = gst_adapter_peek (parse->adapter, min_size);
+      tmpbuf = gst_buffer_new_and_alloc (min_size);
+      memcpy (GST_BUFFER_DATA (tmpbuf), data, min_size);
+
+      skip = 0;
+      if (bclass->check_valid_frame (parse, tmpbuf, &fsize, &skip)) {
+        gst_buffer_unref (tmpbuf);
+        break;
+      }
+      gst_buffer_unref (tmpbuf);
+      if (skip) {
+        GST_LOG ("finding sync, skipping %d bytes", skip);
+        gst_adapter_flush (parse->adapter, skip);
+        parse->priv->offset += skip;
+      } else {
+        GST_LOG ("finding sync, skipping 1 byte");
+        gst_adapter_flush (parse->adapter, 1);
+        parse->priv->offset++;
+      }
+    }
+
+    if (skip) {
+      GST_LOG ("skipping %d bytes", skip);
+      gst_adapter_flush (parse->adapter, skip);
+      parse->priv->offset += skip;
+    }
+
+    /* Grab lock to prevent a race with FLUSH_START handler */
+    GST_PAD_STREAM_LOCK (parse->srcpad);
+
+    /* FLUSH_START event causes the "flushing" flag to be set. In this
+     * case we can leave the frame pushing loop */
+    if (parse->priv->flushing) {
+      GST_PAD_STREAM_UNLOCK (parse->srcpad);
+      break;
+    }
+
+    /* FIXME: Would it be more efficient to make a subbuffer instead? */
+    outbuf = gst_adapter_take_buffer (parse->adapter, fsize);
+
+    /* Subclass may want to know the data offset */
+    GST_BUFFER_OFFSET (outbuf) = parse->priv->offset;
+    parse->priv->offset += fsize;
+
+    ret = gst_base_parse_handle_and_push_buffer (parse, bclass, outbuf);
+    GST_PAD_STREAM_UNLOCK (parse->srcpad);
+
+    if (ret != GST_FLOW_OK) {
+      GST_LOG ("push returned %d", ret);
+      break;
+    }
+  }
+
+done:
+  GST_LOG ("chain leaving");
+  return ret;
+}
+
+
+
+/**
+ * gst_base_parse_loop:
+ * @pad: GstPad
+ *
+ */
+static void
+gst_base_parse_loop (GstPad * pad)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *klass;
+  GstBuffer *buffer, *outbuf;
+  gboolean ret = FALSE;
+  guint fsize = 0, skip = 0, min_size;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  if (parse->close_segment) {
+    GST_DEBUG ("loop sending close segment");
+    gst_pad_push_event (parse->srcpad, parse->close_segment);
+    parse->close_segment = NULL;
+  }
+
+  if (parse->pending_segment) {
+    GST_DEBUG ("loop push pending segment");
+    gst_pad_push_event (parse->srcpad, parse->pending_segment);
+    parse->pending_segment = NULL;
+  }
+
+  GST_BASE_PARSE_LOCK (parse);
+  min_size = parse->priv->min_frame_size;
+  GST_BASE_PARSE_UNLOCK (parse);
+
+  /* TODO: Check if we reach segment stop limit */
+
+  while (TRUE) {
+    ret = gst_pad_pull_range (parse->sinkpad, parse->priv->offset,
+                              min_size, &buffer);
+
+    if (ret == GST_FLOW_UNEXPECTED)
+      goto eos;
+    else if (ret != GST_FLOW_OK)
+      goto need_pause;
+
+    /* EOS */
+    if (GST_BUFFER_SIZE (buffer) < min_size) {
+      gst_buffer_unref (buffer);
+      goto eos;
+    }
+
+    skip = 0;
+    if (klass->check_valid_frame (parse, buffer, &fsize, &skip)) {
+      break;
+    }
+    if (skip) {
+      GST_LOG ("finding sync, skipping %d bytes", skip);
+      parse->priv->offset += skip;
+    } else {
+      GST_LOG ("finding sync, skipping 1 byte");
+      parse->priv->offset++;
+    }
+    GST_DEBUG_OBJECT (parse, "finding sync...");
+    gst_buffer_unref (buffer);
+  }
+
+  if (fsize < GST_BUFFER_SIZE (buffer)) {
+    outbuf = gst_buffer_create_sub (buffer, 0, fsize);
+    gst_buffer_unref (buffer);
+  }
+  else {
+    outbuf = buffer;
+  }
+
+  parse->priv->offset += fsize + skip;
+
+  /* This always unrefs the outbuf, even if error occurs */
+  ret = gst_base_parse_handle_and_push_buffer (parse, klass, outbuf);
+
+  if (ret != GST_FLOW_OK) {
+    GST_DEBUG_OBJECT (parse, "flow: %s", gst_flow_get_name (ret));
+    if (GST_FLOW_IS_FATAL (ret)) {
+      GST_ELEMENT_ERROR (parse, STREAM, FAILED, (NULL),
+                         ("streaming task paused, reason: %s",
+                          gst_flow_get_name (ret)));
+      gst_pad_push_event (pad, gst_event_new_eos ());
+    }
+    goto need_pause;
+  }
+  else {
+    /* Update current running segment position */
+    gst_segment_set_last_stop (&parse->segment, GST_FORMAT_TIME,
+                                GST_BUFFER_TIMESTAMP (outbuf) +
+                                    GST_BUFFER_DURATION (outbuf));
+  }
+
+  gst_object_unref (parse);
+  return;
+
+need_pause:
+  {
+    GST_LOG_OBJECT (parse, "pausing task");
+    gst_pad_pause_task (pad);
+    gst_object_unref (parse);
+    return;
+  }
+eos:
+  {
+    GST_LOG_OBJECT (parse, "pausing task %d", ret);
+    gst_pad_push_event (parse->srcpad, gst_event_new_eos ());
+    gst_pad_pause_task (pad);
+    gst_object_unref (parse);
+    return;
+  }
+}
+
+
+/**
+ * gst_base_parse_sink_activate:
+ * @sinkpad: #GstPad to be activated.
+ *
+ * Returns: TRUE if activation succeeded.
+ */
+static gboolean
+gst_base_parse_sink_activate (GstPad * sinkpad)
+{
+  GstBaseParse *parse;
+  gboolean result = TRUE;
+
+  GST_DEBUG ("sink activate");
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (sinkpad));
+
+  if (gst_pad_check_pull_range (sinkpad)) {
+    GST_DEBUG ("trying to activate in pull mode");
+    result = gst_pad_activate_pull (sinkpad, TRUE);
+  } else {
+    GST_DEBUG ("trying to activate in push mode");
+    result = gst_pad_activate_push (sinkpad, TRUE);
+  }
+
+  GST_DEBUG ("sink activate return %d", result);
+  gst_object_unref (parse);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_activate:
+ * @parse: #GstBaseParse.
+ * @active: TRUE if element will be activated, FALSE if disactivated.
+ *
+ * Returns: TRUE if the operation succeeded.
+ */
+static gboolean
+gst_base_parse_activate (GstBaseParse *parse, gboolean active)
+{
+  GstBaseParseClass *klass;
+  gboolean result = FALSE;
+
+  GST_DEBUG ("activate");
+
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  if (active) {
+    if (parse->priv->pad_mode == GST_ACTIVATE_NONE && klass->start)
+      result = klass->start (parse);
+
+    GST_OBJECT_LOCK (parse);
+    gst_segment_init (&parse->segment, GST_FORMAT_TIME);
+    parse->priv->duration = -1;
+    parse->priv->discont = FALSE;
+    parse->priv->flushing = FALSE;
+    parse->priv->offset = 0;
+    GST_OBJECT_UNLOCK (parse);
+  }
+  else {
+    /* We must make sure streaming has finished before resetting things
+    * and calling the ::stop vfunc */
+    GST_PAD_STREAM_LOCK (parse->sinkpad);
+    GST_PAD_STREAM_UNLOCK (parse->sinkpad);
+
+    if (parse->priv->pad_mode != GST_ACTIVATE_NONE && klass->stop)
+      result = klass->stop (parse);
+
+    parse->priv->pad_mode = GST_ACTIVATE_NONE;
+  }
+  GST_DEBUG ("activate: %d", result);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_sink_activate_push:
+ * @pad: #GstPad.
+ * @active:
+ *
+ * Returns: TRUE if activation succeeded.
+ */
+static gboolean
+gst_base_parse_sink_activate_push (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstBaseParse *parse;
+
+  GST_DEBUG ("sink activate push");
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+
+  result = gst_base_parse_activate (parse, active);
+
+  if (result)
+    parse->priv->pad_mode = active ? GST_ACTIVATE_PUSH : GST_ACTIVATE_NONE;
+
+  gst_object_unref (parse);
+  GST_DEBUG ("sink activate push: %d", result);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_sink_activate_pull:
+ * @sinkpad: #GstPad to be activated.
+ * @active:
+ *
+ * Returns: TRUE if activation succeeded.
+ */
+static gboolean
+gst_base_parse_sink_activate_pull (GstPad * sinkpad, gboolean active)
+{
+  gboolean result = FALSE;
+  GstBaseParse *parse;
+
+  GST_DEBUG ("activate pull");
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (sinkpad));
+
+  result = gst_base_parse_activate (parse, active);
+
+  if (result) {
+    if (active) {
+      result &= gst_pad_start_task (sinkpad,
+                                    (GstTaskFunction) gst_base_parse_loop,
+                                    sinkpad);
+    } else {
+      result &= gst_pad_stop_task (sinkpad);
+    }
+  }
+
+  if (result)
+    parse->priv->pad_mode = active ? GST_ACTIVATE_PULL : GST_ACTIVATE_NONE;
+
+  gst_object_unref (parse);
+  GST_DEBUG ("sink activate pull: %d", result);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_set_duration:
+ * @parse: #GstBaseParse.
+ * @fmt: #GstFormat.
+ * @duration: duration value.
+ *
+ * Sets the duration of the currently playing media.
+ */
+void gst_base_parse_set_duration (GstBaseParse *parse,
+                                  GstFormat fmt,
+                                  gint64 duration)
+{
+  g_return_if_fail (parse != NULL);
+
+  GST_BASE_PARSE_LOCK (parse);
+  parse->priv->duration = duration;
+  parse->priv->duration_fmt = fmt;
+  GST_DEBUG_OBJECT (parse, "set duration: %lld", duration);
+  GST_BASE_PARSE_UNLOCK (parse);
+}
+
+
+/**
+ * gst_base_parse_set_min_frame_size:
+ * @parse: #GstBaseParse.
+ * @min_size: Minimum size of the data that this base class should give to
+ *            subclass.
+ *
+ * Subclass can use this function to tell the base class that it needs to
+ * give at least #min_size buffers.
+ */
+void gst_base_parse_set_min_frame_size (GstBaseParse *parse, guint min_size)
+{
+  g_return_if_fail (parse != NULL);
+
+  GST_BASE_PARSE_LOCK (parse);
+  parse->priv->min_frame_size = min_size;
+  GST_DEBUG_OBJECT (parse, "set frame_min_size: %d", min_size);
+  GST_BASE_PARSE_UNLOCK (parse);
+}
+
+
+/**
+ * gst_base_parse_get_querytypes:
+ * @pad: GstPad
+ *
+ * Returns: A table of #GstQueryType items describing supported query types.
+ */
+static const GstQueryType *
+gst_base_parse_get_querytypes (GstPad * pad)
+{
+  static const GstQueryType list[] = {
+    GST_QUERY_POSITION,
+    GST_QUERY_DURATION,
+    GST_QUERY_FORMATS,
+    GST_QUERY_SEEKING,
+    GST_QUERY_CONVERT,
+    0
+  };
+
+  return list;
+}
+
+
+/**
+ * gst_base_parse_query:
+ * @pad: #GstPad.
+ * @query: #GstQuery.
+ *
+ * Returns: TRUE on success.
+ */
+static gboolean
+gst_base_parse_query (GstPad * pad, GstQuery * query)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *klass;
+  gboolean res = FALSE;
+
+  parse = GST_BASE_PARSE (GST_PAD_PARENT (pad));
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  /* If subclass doesn't provide conversion function we can't reply
+     to the query either */
+  if (!klass->convert) {
+    return FALSE;
+  }
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_POSITION:
+    {
+      gint64 dest_value;
+      GstFormat format;
+
+      GST_DEBUG ("position query");
+
+      gst_query_parse_position (query, &format, NULL);
+
+      if (format != GST_FORMAT_TIME) {
+        return gst_pad_query_default (pad, query);
+      }
+
+      /* priv->offset is updated in both PUSH/PULL modes */
+      res = klass->convert (parse, GST_FORMAT_TIME, parse->priv->offset,
+                            GST_FORMAT_TIME, &dest_value);
+
+      if (res)
+        gst_query_set_position (query, GST_FORMAT_TIME, dest_value);
+
+      break;
+    }
+    case GST_QUERY_DURATION:
+    {
+      GstFormat format;
+
+      GST_DEBUG ("duration query");
+
+      gst_query_parse_duration (query, &format, NULL);
+
+      g_mutex_lock (parse->parse_lock);
+      if (parse->priv->duration != -1 &&
+          format == parse->priv->duration_fmt)
+      {
+        gst_query_set_duration (query, parse->priv->duration_fmt,
+                                parse->priv->duration);
+        g_mutex_unlock (parse->parse_lock);
+        res = TRUE;
+      }
+      else {
+        g_mutex_unlock (parse->parse_lock);
+        res = gst_pad_query_default (pad, query);
+      }
+      break;
+    }
+    case GST_QUERY_SEEKING:
+    {
+      GstFormat fmt;
+
+      GST_DEBUG ("seeking query");
+
+      gst_query_parse_seeking (query, &fmt, NULL, NULL, NULL);
+
+      if (fmt != GST_FORMAT_TIME || parse->priv->pad_mode != GST_ACTIVATE_PULL)
+      {
+        return gst_pad_query_default (pad, query);
+      }
+
+      gst_query_set_seeking (query, GST_FORMAT_TIME, TRUE, 0,
+                             (parse->priv->duration == -1) ?
+                                 GST_CLOCK_TIME_NONE : parse->priv->duration);
+      res = TRUE;
+      break;
+    }
+    case GST_QUERY_FORMATS:
+      gst_query_set_formatsv (query, 3, fmtlist);
+      res = TRUE;
+      break;
+
+    case GST_QUERY_CONVERT:
+    {
+      GstFormat src_format, dest_format;
+      gint64 src_value, dest_value;
+
+      gst_query_parse_convert (query, &src_format, &src_value,
+                               &dest_format, &dest_value);
+
+      /* We require all those values to be given */
+      if (src_format && src_value && dest_format && dest_value ) {
+        res = klass->convert (parse, src_format, src_value,
+                              dest_format, &dest_value);
+        if (res) {
+          gst_query_set_convert (query, src_format, src_value,
+                                 dest_format, dest_value);
+        }
+      }
+      break;
+    }
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+  return res;
+}
+
+
+/**
+ * gst_base_parse_handle_seek:
+ * @parse: #GstBaseParse.
+ * @event: #GstEvent.
+ *
+ * Returns: TRUE if seek succeeded.
+ */
+static gboolean
+gst_base_parse_handle_seek (GstBaseParse * parse, GstEvent * event)
+{
+  GstBaseParseClass *klass;
+  gdouble rate;
+  GstFormat format;
+  GstSeekFlags flags;
+  GstSeekType cur_type = GST_SEEK_TYPE_NONE, stop_type;
+  gboolean flush, update, res = TRUE;
+  gint64 cur, stop, seekpos;
+  GstSegment seeksegment = { 0, };
+
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  gst_event_parse_seek (event, &rate, &format, &flags,
+                        &cur_type, &cur, &stop_type, &stop);
+
+  /* no negative rates yet */
+  if (rate < 0.0)
+    goto negative_rate;
+
+  if (cur_type != GST_SEEK_TYPE_SET)
+    goto wrong_type;
+
+  /* For any format other than TIME, see if upstream handles
+   * it directly or fail. For TIME, try upstream, but do it ourselves if
+   * it fails upstream */
+  if (format != GST_FORMAT_TIME) {
+    gst_event_ref (event);
+    return gst_pad_push_event (parse->sinkpad, event);
+  }
+  else {
+    gst_event_ref (event);
+    if (gst_pad_push_event (parse->sinkpad, event))
+      return TRUE;
+  }
+
+  /* get flush flag */
+  flush = flags & GST_SEEK_FLAG_FLUSH;
+
+  GstFormat dstformat = GST_FORMAT_BYTES;
+  if (!gst_pad_query_convert (parse->srcpad, format, cur,
+                              &dstformat, &seekpos))
+  {
+    GST_DEBUG ("conversion failed");
+    return FALSE;
+  }
+
+  GST_DEBUG ("seek position %lld in bytes: %lld", cur, seekpos);
+
+  if (parse->priv->pad_mode == GST_ACTIVATE_PULL) {
+    gint64 last_stop;
+
+    GST_DEBUG ("seek in PULL mode");
+
+    if (flush) {
+      if (parse->srcpad) {
+        GST_DEBUG ("sending flush start");
+        gst_pad_push_event (parse->srcpad, gst_event_new_flush_start ());
+      }
+    }
+    else {
+      gst_pad_pause_task (parse->sinkpad);
+    }
+
+    /* we should now be able to grab the streaming thread because we stopped it
+     * with the above flush/pause code */
+    GST_PAD_STREAM_LOCK (parse->sinkpad);
+
+    /* save current position */
+    last_stop = parse->segment.last_stop;
+    GST_DEBUG ("stopped streaming at %" G_GINT64_FORMAT, last_stop);
+
+    /* copy segment, we need this because we still need the old
+     * segment when we close the current segment. */
+    memcpy (&seeksegment, &parse->segment, sizeof (GstSegment));
+
+    GST_DEBUG ("configuring seek");
+    gst_segment_set_seek (&seeksegment, rate, format, flags,
+                          cur_type, cur, stop_type, stop, &update);
+
+    /* figure out the last position we need to play. If it's configured (stop !=
+     * -1), use that, else we play until the total duration of the file */
+    if ((stop = seeksegment.stop) == -1)
+      stop = seeksegment.duration;
+
+    parse->priv->offset = seekpos;
+
+    /* prepare for streaming again */
+    if (flush) {
+      GST_DEBUG ("sending flush stop");
+      gst_pad_push_event (parse->srcpad, gst_event_new_flush_stop ());
+    }
+    else {
+      if (parse->close_segment)
+        gst_event_unref (parse->close_segment);
+
+      parse->close_segment = gst_event_new_new_segment (TRUE,
+          parse->segment.rate, parse->segment.format,
+          parse->segment.accum, parse->segment.last_stop,
+          parse->segment.accum);
+
+      /* keep track of our last_stop */
+      seeksegment.accum = parse->segment.last_stop;
+
+      GST_DEBUG_OBJECT (parse, "Created close seg format %d, "
+          "start = %" GST_TIME_FORMAT ", stop = %" GST_TIME_FORMAT
+          ", pos = %" GST_TIME_FORMAT, format,
+          GST_TIME_ARGS (parse->segment.accum),
+          GST_TIME_ARGS (parse->segment.last_stop),
+          GST_TIME_ARGS (parse->segment.accum));
+    }
+
+    memcpy (&parse->segment, &seeksegment, sizeof (GstSegment));
+
+    /* store the newsegment event so it can be sent from the streaming thread.*/
+    if (parse->pending_segment)
+      gst_event_unref (parse->pending_segment);
+
+    /* This will be sent later in _loop() */
+    parse->pending_segment =
+        gst_event_new_new_segment (FALSE, parse->segment.rate,
+                                   parse->segment.format,
+                                   parse->segment.last_stop, stop,
+                                   parse->segment.last_stop);
+
+    GST_DEBUG_OBJECT (parse, "Created newseg format %d, "
+        "start = %" GST_TIME_FORMAT ", stop = %" GST_TIME_FORMAT
+        ", pos = %" GST_TIME_FORMAT, format,
+        GST_TIME_ARGS (parse->segment.last_stop),
+        GST_TIME_ARGS (stop),
+        GST_TIME_ARGS (parse->segment.last_stop));
+
+    /* mark discont if we are going to stream from another position. */
+    if (last_stop != parse->segment.last_stop) {
+      GST_DEBUG ("mark DISCONT, we did a seek to another position");
+      parse->priv->discont = TRUE;
+    }
+
+    /* Start streaming thread if paused */
+    gst_pad_start_task (parse->sinkpad,
+                        (GstTaskFunction) gst_base_parse_loop,
+                         parse->sinkpad);
+
+    GST_PAD_STREAM_UNLOCK (parse->sinkpad);
+  }
+  else {
+    /* The only thing we need to do in PUSH-mode is to send the
+       seek event (in bytes) to upstream. Segment / flush handling happens
+       in corresponding src event handlers */
+    GST_DEBUG ("seek in PUSH mode");
+    GstEvent *new_event = gst_event_new_seek(rate, GST_FORMAT_BYTES, flush,
+                                             GST_SEEK_TYPE_SET, seekpos,
+                                             stop_type, stop);
+
+    res = gst_pad_push_event (parse->sinkpad, new_event);
+  }
+
+done:
+  return res;
+
+  /* ERRORS */
+negative_rate:
+  {
+    GST_DEBUG ("negative playback rates are not supported yet.");
+    res = FALSE;
+    goto done;
+  }
+wrong_type:
+  {
+    GST_DEBUG ("unsupported seek type.");
+    res = FALSE;
+    goto done;
+  }
+}
+
+
+/**
+ * gst_base_parse_sink_setcaps:
+ * @pad: #GstPad.
+ * @caps: #GstCaps.
+ *
+ * Returns: TRUE if caps were accepted.
+ */
+static gboolean
+gst_base_parse_sink_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *klass;
+  gboolean res = TRUE;
+
+  gchar *caps_str = gst_caps_to_string (caps);
+  GST_DEBUG ("setcaps: %s", caps_str);
+  g_free (caps_str);
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  if (klass->set_sink_caps)
+    res = klass->set_sink_caps (parse, caps);
+
+  parse->negotiated = res;
+  gst_object_unref (parse);
+  return gst_pad_set_caps (pad, caps);
+}
+
Index: libs/gst/base/gstbaseparse.h
===================================================================
--- libs/gst/base/gstbaseparse.h	(revision 0)
+++ libs/gst/base/gstbaseparse.h	(revision 6859)
@@ -0,0 +1,226 @@
+/* GStreamer
+ * Copyright (C) 2008 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Stefan Kost <stefan.kost@nokia.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.
+ */
+
+#ifndef __GST_BASE_PARSE_H__
+#define __GST_BASE_PARSE_H__
+
+#include <gst/gst.h>
+#include <gst/base/gstadapter.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_BASE_PARSE		   (gst_base_parse_get_type())
+#define GST_BASE_PARSE(obj)		   (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BASE_PARSE,GstBaseParse))
+#define GST_BASE_PARSE_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_BASE_PARSE,GstBaseParseClass))
+#define GST_BASE_PARSE_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj),GST_TYPE_BASE_PARSE,GstBaseParseClass))
+#define GST_IS_BASE_PARSE(obj)	   (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BASE_PARSE))
+#define GST_IS_BASE_PARSE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BASE_PARSE))
+#define GST_BASE_PARSE_CAST(obj)	((GstBaseParse *)(obj))
+
+/**
+ * GST_BASE_PARSE_SINK_NAME:
+ *
+ * the name of the templates for the sink pad
+ */
+#define GST_BASE_PARSE_SINK_NAME	"sink"
+/**
+ * GST_BASE_PARSE_SRC_NAME:
+ *
+ * the name of the templates for the source pad
+ */
+#define GST_BASE_PARSE_SRC_NAME	"src"
+
+/**
+ * GST_BASE_PARSE_SRC_PAD:
+ * @obj: base parse instance
+ *
+ * Gives the pointer to the source #GstPad object of the element.
+ *
+ * Since: 0.10.17
+ */
+#define GST_BASE_PARSE_SRC_PAD(obj)		(GST_BASE_PARSE_CAST (obj)->srcpad)
+
+/**
+ * GST_BASE_PARSE_SINK_PAD:
+ * @obj: base parse instance
+ *
+ * Gives the pointer to the sink #GstPad object of the element.
+ *
+ * Since: 0.10.17
+ */
+#define GST_BASE_PARSE_SINK_PAD(obj)	(GST_BASE_PARSE_CAST (obj)->sinkpad)
+
+/**
+ * GST_BASE_PARSE_FLOW_DROPPED:
+ *
+ * A #GstFlowReturn that can be returned from parse_frame to
+ * indicate that no output buffer was generated.
+ *
+ * Since: 0.10.17
+ */
+#define GST_BASE_PARSE_FLOW_DROPPED   GST_FLOW_CUSTOM_SUCCESS
+
+/**
+ * GST_BASE_PARSE_LOCK:
+ * @obj: base parse instance
+ *
+ * Obtain a lock to protect the parse function from concurrent access.
+ *
+ * Since: 0.10.17
+ */
+#define GST_BASE_PARSE_LOCK(obj)   g_mutex_lock (GST_BASE_PARSE_CAST (obj)->parse_lock)
+
+/**
+ * GST_BASE_PARSE_UNLOCK:
+ * @obj: base parse instance
+ *
+ * Release the lock that protects the parse function from concurrent access.
+ *
+ * Since: 0.10.17
+ */
+#define GST_BASE_PARSE_UNLOCK(obj) g_mutex_unlock (GST_BASE_PARSE_CAST (obj)->parse_lock)
+
+typedef struct _GstBaseParse GstBaseParse;
+typedef struct _GstBaseParseClass GstBaseParseClass;
+typedef struct _GstBaseParsePrivate GstBaseParsePrivate;
+
+/**
+ * GstBaseParse:
+ * @element: the parent element.
+ *
+ * The opaque #GstBaseParse data structure.
+ */
+struct _GstBaseParse {
+  GstElement	 element;
+  GstAdapter   *adapter;
+
+  /*< protected >*/
+  /* source and sink pads */
+  GstPad	*sinkpad;
+  GstPad	*srcpad;
+
+  /* MT-protected (with STREAM_LOCK) */
+  GstSegment     segment;
+
+  /* Newsegment event to be sent after SEEK */
+  GstEvent       *pending_segment;
+
+  /* Segment event that closes the running segment prior to SEEK */
+  GstEvent       *close_segment;
+
+  /* Caps nego done already? */
+  gboolean   negotiated;
+
+  GMutex	*parse_lock;
+
+  /*< private >*/
+  GstBaseParsePrivate *priv;
+
+};
+
+/**
+ * GstBaseParseClass:
+ * @start:          Optional.
+ *                  Called when the element starts processing.
+ *                  Allows opening external resources.
+ * @stop:           Optional.
+ *                  Called when the element stops processing.
+ *                  Allows closing external resources.
+ * @set_sink_caps:  allows the subclass to be notified of the actual caps set.
+ * @check_valid_frame:  Check if the given piece of data contains a valid
+ *                      frame.
+ * @parse_frame:    Parse the already checked frame. Subclass need to
+ *                  set the buffer timestamp, duration, caps and possibly
+ *                  other necessary metadata.
+ * @convert:        Optional.
+ *                  Convert between formats.
+ * @find_frame:     Optional.
+ *                  Finds a frame. Gets a position passed and should return
+ *                  TRUE and the offset in bytes where this position is.
+ *                  Will only be called in pull mode and the subclass can pull
+ *                  whatever it wants from upstream. If not implemented,
+ *                  the base class will implement it by calling
+ *                  @check_valid_frame and @parse_frame to find the wanted
+ *                  frame and build a seek table.
+ * @event:          Optional.
+ *                  Event handler on the sink pad. This function should return
+ *                  TRUE if the event was handled and can be dropped.
+ * @src_event:      Optional.
+ *                  Event handler on the source pad. Should return TRUE
+ *                  if the event was handled and can be dropped.
+ *
+ * Subclasses can override any of the available virtual methods or not, as
+ * needed. At minimum @check_valid_frame and @parse_frame needs to be
+ * overridden.
+ */
+struct _GstBaseParseClass {
+  GstElementClass parent_class;
+
+  /*< public >*/
+  /* virtual methods for subclasses */
+
+  gboolean      (*start)              (GstBaseParse *parse);
+
+  gboolean      (*stop)               (GstBaseParse *parse);
+
+  gboolean      (*set_sink_caps)      (GstBaseParse *parse,
+                                       GstCaps *caps);
+
+  gboolean      (*check_valid_frame)  (GstBaseParse *parse,
+                                       GstBuffer *buffer,
+                                       guint *framesize,
+                                       guint *skipsize);
+
+  GstFlowReturn (*parse_frame)        (GstBaseParse *parse,
+                                       GstBuffer *buffer);
+
+  gboolean      (*convert)            (GstBaseParse * parse,
+                                       GstFormat src_format,
+                                       gint64 src_value,
+                                       GstFormat dest_format,
+                                       gint64 * dest_value);
+
+  gboolean      (*find_frame)         (GstBaseParse *parse,
+                                       GstFormat src_format,
+                                       gint64 src_value,
+                                       gint64 * dest_value);
+
+  gboolean      (*event)              (GstBaseParse *parse,
+                                       GstEvent *event);
+
+  gboolean      (*src_event)          (GstBaseParse *parse,
+                                       GstEvent *event);
+
+};
+
+GType           gst_base_parse_get_type         (void);
+
+
+void gst_base_parse_set_duration (GstBaseParse *parse,
+                                  GstFormat fmt,
+                                  gint64 duration);
+
+void gst_base_parse_set_min_frame_size (GstBaseParse *parse,
+                                        guint min_size);
+
+G_END_DECLS
+
+#endif /* __GST_BASE_PARSE_H__ */
Index: libs/gst/base/Makefile.am
===================================================================
--- libs/gst/base/Makefile.am	(revision 6761)
+++ libs/gst/base/Makefile.am	(revision 6859)
@@ -10,7 +10,8 @@
 	gstcollectpads.c	\
 	gstpushsrc.c		\
 	gsttypefindhelper.c	\
-	gstdataqueue.c
+	gstdataqueue.c		\
+	gstbaseparse.c
 
 libgstbase_@GST_MAJORMINOR@_la_CFLAGS = $(GST_OBJ_CFLAGS)
 libgstbase_@GST_MAJORMINOR@_la_LIBADD = $(GST_OBJ_LIBS)
@@ -27,7 +28,8 @@
 	gstcollectpads.h	\
 	gstpushsrc.h		\
 	gsttypefindhelper.h	\
-	gstdataqueue.h
+	gstdataqueue.h		\
+	gstbaseparse.h
 
 CLEANFILES = *.gcno *.gcda *.gcov
 
Index: docs/libs/gstreamer-libs-sections.txt
===================================================================
--- docs/libs/gstreamer-libs-sections.txt	(revision 6761)
+++ docs/libs/gstreamer-libs-sections.txt	(revision 6859)
@@ -221,6 +221,40 @@
 
 
 <SECTION>
+<FILE>gstbaseparse</FILE>
+<TITLE>GstBaseParse</TITLE>
+<INCLUDE>gst/base/gstbaseparse.h</INCLUDE>
+GstBaseParse
+GstBaseParseClass
+
+gst_base_parse_set_duration
+gst_base_parse_set_min_frame_size
+
+GST_BASE_PARSE_SINK_NAME
+GST_BASE_PARSE_SRC_NAME
+GST_BASE_PARSE_SINK_PAD
+GST_BASE_PARSE_SRC_PAD
+
+GST_BASE_PARSE_FLOW_DROPPED
+
+GST_BASE_PARSE_LOCK
+GST_BASE_PARSE_UNLOCK
+
+<SUBSECTION Standard>
+GST_BASE_PARSE
+GST_IS_BASE_PARSE
+GST_TYPE_BASE_PARSE
+GST_BASE_PARSE_CLASS
+GST_IS_BASE_PARSE_CLASS
+GST_BASE_PARSE_GET_CLASS
+GST_BASE_PARSE_CAST
+<SUBSECTION Private>
+GstBaseParsePrivate
+gst_base_parse_get_type
+</SECTION>
+
+
+<SECTION>
 <FILE>gstbasesrc</FILE>
 <TITLE>GstBaseSrc</TITLE>
 <INCLUDE>gst/base/gstbasesrc.h</INCLUDE>
Index: docs/libs/gstreamer-libs.types
===================================================================
--- docs/libs/gstreamer-libs.types	(revision 6761)
+++ docs/libs/gstreamer-libs.types	(revision 6859)
@@ -10,6 +10,8 @@
 gst_lfo_control_source_get_type
 #include <gst/base/gstadapter.h>
 gst_adapter_get_type
+#include <gst/base/gstbaseparse.h>
+gst_base_parse_get_type
 #include <gst/base/gstbasesrc.h>
 gst_base_src_get_type
 #include <gst/base/gstbasesink.h>
Index: docs/libs/gstreamer-libs-docs.sgml
===================================================================
--- docs/libs/gstreamer-libs-docs.sgml	(revision 6761)
+++ docs/libs/gstreamer-libs-docs.sgml	(revision 6859)
@@ -5,6 +5,7 @@
 %version-entities;
 
 <!ENTITY GstAdapter SYSTEM "xml/gstadapter.xml">
+<!ENTITY GstBaseParse SYSTEM "xml/gstbaseparse.xml">
 <!ENTITY GstBaseSrc SYSTEM "xml/gstbasesrc.xml">
 <!ENTITY GstBaseSink SYSTEM "xml/gstbasesink.xml">
 <!ENTITY GstBaseTransform SYSTEM "xml/gstbasetransform.xml">
@@ -58,6 +59,7 @@
         by elements and utillity classes that are most useful for plugin developers.
       </para>
 
+      &GstBaseParse;
       &GstBaseSrc;
       &GstBaseSink;
       &GstBaseTransform;

