Add FLAC parser, based on GstBaseParse. Also add the bit and byte reader that will be added to libgstbase later.

Original commit message from CVS:
* configure.ac:
* gst/flacparse/Makefile.am:
* gst/flacparse/gstbaseparse.c: (gst_base_parse_get_type),
(gst_base_parse_base_init), (gst_base_parse_base_finalize),
(gst_base_parse_finalize), (gst_base_parse_class_init),
(gst_base_parse_init), (gst_base_parse_check_frame),
(gst_base_parse_parse_frame), (gst_base_parse_bytepos_to_time),
(gst_base_parse_sink_event), (gst_base_parse_sink_eventfunc),
(gst_base_parse_src_event), (gst_base_parse_src_eventfunc),
(gst_base_parse_is_seekable), (gst_base_parse_push_buffer),
(gst_base_parse_handle_and_push_buffer), (gst_base_parse_drain),
(gst_base_parse_chain), (gst_base_parse_pull_range),
(gst_base_parse_loop), (gst_base_parse_sink_activate),
(gst_base_parse_activate), (gst_base_parse_sink_activate_push),
(gst_base_parse_sink_activate_pull), (gst_base_parse_set_duration),
(gst_base_parse_set_min_frame_size),
(gst_base_parse_get_querytypes), (gst_base_parse_query),
(gst_base_parse_handle_seek), (gst_base_parse_sink_setcaps):
* gst/flacparse/gstbaseparse.h:
* gst/flacparse/gstbitreader.c: (gst_bit_reader_new),
(gst_bit_reader_new_from_buffer), (gst_bit_reader_free),
(gst_bit_reader_init), (gst_bit_reader_init_from_buffer),
(gst_bit_reader_set_pos), (gst_bit_reader_get_pos),
(gst_bit_reader_get_remaining), (gst_bit_reader_skip),
(gst_bit_reader_skip_to_byte):
* gst/flacparse/gstbitreader.h:
* gst/flacparse/gstbytereader.c: (GDOUBLE_SWAP_LE_BE),
(GFLOAT_SWAP_LE_BE), (gst_byte_reader_new),
(gst_byte_reader_new_from_buffer), (gst_byte_reader_free),
(gst_byte_reader_init), (gst_byte_reader_init_from_buffer),
(gst_byte_reader_set_pos), (gst_byte_reader_get_pos),
(gst_byte_reader_get_remaining), (gst_byte_reader_skip),
(gst_byte_reader_get_uint8), (gst_byte_reader_get_int8),
(gst_byte_reader_peek_uint8), (gst_byte_reader_peek_int8),
(gst_byte_reader_get_uint24_le), (gst_byte_reader_get_uint24_be),
(gst_byte_reader_get_int24_le), (gst_byte_reader_get_int24_be),
(gst_byte_reader_peek_uint24_le), (gst_byte_reader_peek_uint24_be),
(gst_byte_reader_peek_int24_le), (gst_byte_reader_peek_int24_be):
* gst/flacparse/gstbytereader.h:
* gst/flacparse/gstflac.c: (plugin_init):
* gst/flacparse/gstflacparse.c: (gst_flac_parse_base_init),
(gst_flac_parse_class_init), (gst_flac_parse_init),
(gst_flac_parse_finalize), (gst_flac_parse_start),
(gst_flac_parse_stop), (gst_flac_parse_get_frame_size),
(gst_flac_parse_check_valid_frame),
(gst_flac_parse_handle_streaminfo),
(gst_flac_parse_handle_vorbiscomment),
(gst_flac_parse_handle_picture), (_value_array_append_buffer),
(gst_flac_parse_handle_headers), (gst_flac_parse_generate_headers),
(gst_flac_parse_parse_frame):
* gst/flacparse/gstflacparse.h:
Add FLAC parser, based on GstBaseParse. Also add the bit and byte reader
that will be added to libgstbase later.
The FLAC parser is currently not 100% bug free and fails to get the
correct frame size for some frames in some streams.

1 files changed, 1763 insertions, 0 deletions

diff --git a/gst/flacparse/gstbaseparse.c b/gst/flacparse/gstbaseparse.c
new file mode 100644
index 00000000..dd990ab3
--- /dev/null
+++ b/gst/flacparse/gstbaseparse.c
@@ -0,0 +1,1763 @@
+/* GStreamer
+ * Copyright (C) 2008 Nokia Corporation. All rights reserved.
+ *   Contact: Stefan Kost <stefan.kost@nokia.com>
+ * Copyright (C) 2008 Sebastian Dröge <sebastian.droege@collabora.co.uk>.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * 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 must return 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. The passed buffer
+ *       is read-only.
+ *     </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>
+ *
+ */
+
+/* TODO:
+ *  - Better segment handling:
+ *    - NEWSEGMENT for gaps
+ *    - Not NEWSEGMENT starting at 0 but at first frame timestamp
+ *  - GstIndex support
+ *  - Seek table generation and subclass seek entry injection
+ *  - Accurate seeking
+ *  - In push mode provide a queue of adapter-"queued" buffers for upstream
+ *    buffer metadata
+ *  - Handle upstream timestamps
+ *  - Bitrate tracking => inaccurate seeking, inaccurate duration calculation
+ *  - Let subclass decide if frames outside the segment should be dropped
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "gstbaseparse.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;
+
+  GList *pending_events;
+
+  GstBuffer *cache;
+
+  GstAdapter *adapter;
+
+  guint64 bitrate_sum;
+  guint64 avg_bitrate;
+};
+
+struct _GstBaseParseClassPrivate
+{
+  gpointer _padding;
+};
+
+static GstElementClass *parent_class = NULL;
+
+static void gst_base_parse_base_init (gpointer g_class);
+static void gst_base_parse_base_finalize (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,
+      (GBaseFinalizeFunc) gst_base_parse_base_finalize,
+      (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,
+        "GstFlacBaseParse", &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, gint * 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 gboolean gst_base_parse_is_seekable (GstBaseParse * parse);
+
+static void gst_base_parse_drain (GstBaseParse * parse);
+
+static void
+gst_base_parse_base_init (gpointer g_class)
+{
+  GstBaseParseClass *klass = GST_BASE_PARSE_CLASS (g_class);
+  GstBaseParseClassPrivate *priv;
+
+  GST_DEBUG_CATEGORY_INIT (gst_base_parse_debug, "flacbaseparse", 0,
+      "baseparse element");
+
+  /* TODO: Remove this once GObject supports class private data */
+  priv = g_slice_new0 (GstBaseParseClassPrivate);
+  if (klass->priv)
+    memcpy (priv, klass->priv, sizeof (GstBaseParseClassPrivate));
+  klass->priv = priv;
+}
+
+static void
+gst_base_parse_base_finalize (gpointer g_class)
+{
+  GstBaseParseClass *klass = GST_BASE_PARSE_CLASS (g_class);
+
+  g_slice_free (GstBaseParseClassPrivate, klass->priv);
+  klass->priv = NULL;
+}
+
+static void
+gst_base_parse_finalize (GObject * object)
+{
+  GstBaseParse *parse = GST_BASE_PARSE (object);
+
+  g_mutex_free (parse->parse_lock);
+  g_object_unref (parse->priv->adapter);
+
+  if (parse->pending_segment) {
+    gst_event_replace (&parse->pending_segment, NULL);
+  }
+  if (parse->close_segment) {
+    gst_event_replace (&parse->close_segment, NULL);
+  }
+
+  if (parse->priv->cache) {
+    gst_buffer_unref (parse->priv->cache);
+    parse->priv->cache = NULL;
+  }
+
+  g_list_foreach (parse->priv->pending_events, (GFunc) gst_mini_object_unref,
+      NULL);
+  g_list_free (parse->priv->pending_events);
+  parse->priv->pending_events = 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;
+  klass->is_seekable = gst_base_parse_is_seekable;
+}
+
+static void
+gst_base_parse_init (GstBaseParse * parse, GstBaseParseClass * bclass)
+{
+  GstPadTemplate *pad_template;
+
+  GST_DEBUG_OBJECT (parse, "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_OBJECT (parse, "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_OBJECT (parse, "src created");
+
+  parse->parse_lock = g_mutex_new ();
+  parse->priv->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_OBJECT (parse, "init ok");
+}
+
+
+
+/**
+ * gst_base_parse_check_frame:
+ * @parse: #GstBaseParse.
+ * @buffer: GstBuffer.
+ * @framesize: This will be set to tell the found frame size in bytes.
+ * @skipsize: Output parameter that tells how much data needs to be skipped
+ *            in order to find the following frame header.
+ *
+ * Default callback for check_valid_frame.
+ * 
+ * Returns: Always TRUE.
+ */
+static gboolean
+gst_base_parse_check_frame (GstBaseParse * parse,
+    GstBuffer * buffer, guint * framesize, gint * skipsize)
+{
+  *framesize = GST_BUFFER_SIZE (buffer);
+  *skipsize = 0;
+  return TRUE;
+}
+
+
+/**
+ * gst_base_parse_parse_frame:
+ * @parse: #GstBaseParse.
+ * @buffer: #GstBuffer.
+ *
+ * Default callback for parse_frame.
+ */
+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;
+  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, (gint64 *) pos_in_time);
+  }
+  return res;
+}
+
+
+/**
+ * gst_base_parse_sink_event:
+ * @pad: #GstPad that received the event.
+ * @event: #GstEvent to be handled.
+ *
+ * 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_OBJECT (parse, "handling event %d", GST_EVENT_TYPE (event));
+
+  /* Cache all events except EOS, NEWSEGMENT and FLUSH_STOP if we have a
+   * pending segment */
+  if (parse->pending_segment && GST_EVENT_TYPE (event) != GST_EVENT_EOS
+      && GST_EVENT_TYPE (event) != GST_EVENT_NEWSEGMENT
+      && GST_EVENT_TYPE (event) != GST_EVENT_FLUSH_START
+      && GST_EVENT_TYPE (event) != GST_EVENT_FLUSH_STOP) {
+    parse->priv->pending_events =
+        g_list_append (parse->priv->pending_events, event);
+    ret = TRUE;
+  } else {
+
+    if (bclass->event)
+      handled = bclass->event (parse, event);
+
+    if (!handled)
+      ret = gst_pad_event_default (pad, event);
+  }
+
+  gst_object_unref (parse);
+  GST_DEBUG_OBJECT (parse, "event handled");
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_sink_eventfunc:
+ * @parse: #GstBaseParse.
+ * @event: #GstEvent to be handled.
+ *
+ * Element-level event handler function.
+ *
+ * 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->priv->adapter);
+      parse->priv->flushing = FALSE;
+      parse->priv->discont = TRUE;
+      break;
+
+    case GST_EVENT_EOS:
+      gst_base_parse_drain (parse);
+      break;
+
+    default:
+      break;
+  }
+
+  return handled;
+}
+
+
+/**
+ * gst_base_parse_src_event:
+ * @pad: #GstPad that received the event.
+ * @event: #GstEvent that was received.
+ *
+ * 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_OBJECT (parse, "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_event_default (pad, event);
+
+  gst_object_unref (parse);
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_src_eventfunc:
+ * @parse: #GstBaseParse.
+ * @event: #GstEvent that was received.
+ *
+ * Default srcpad event handler.
+ *
+ * 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;
+  GstBaseParseClass *bclass;
+
+  bclass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+    {
+      if (bclass->is_seekable (parse)) {
+        handled = gst_base_parse_handle_seek (parse, event);
+        gst_event_unref (event);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+  return handled;
+}
+
+
+/**
+ * gst_base_parse_is_seekable:
+ * @parse: #GstBaseParse.
+ *
+ * Default handler for is_seekable.
+ *
+ * Returns: Always TRUE.
+ */
+static gboolean
+gst_base_parse_is_seekable (GstBaseParse * parse)
+{
+  return TRUE;
+}
+
+/**
+ * gst_base_parse_push_buffer:
+ * @parse: #GstBaseParse.
+ * @buffer: #GstBuffer.
+ *
+ * Pushes @buffer on the srcpad and updates the internal state.
+ *
+ * This must be called with srcpad STREAM_LOCK held.
+ *
+ * Returns: #GstFlowReturn
+ */
+GstFlowReturn
+gst_base_parse_push_buffer (GstBaseParse * parse, GstBuffer * buffer)
+{
+  GstClockTime last_stop = GST_CLOCK_TIME_NONE;
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  g_return_val_if_fail (GST_PAD_CAPS (parse->srcpad), GST_FLOW_ERROR);
+
+  if (parse->priv->pad_mode == GST_ACTIVATE_PULL) {
+    if (parse->close_segment) {
+      GST_DEBUG_OBJECT (parse, "loop sending close segment");
+      gst_pad_push_event (parse->srcpad, parse->close_segment);
+      parse->close_segment = NULL;
+    }
+
+    if (parse->pending_segment) {
+      GST_DEBUG_OBJECT (parse, "loop push pending segment");
+      gst_pad_push_event (parse->srcpad, parse->pending_segment);
+      parse->pending_segment = NULL;
+    }
+  } else {
+    if (parse->pending_segment) {
+      GST_DEBUG_OBJECT (parse, "chain pushing a pending segment");
+      gst_pad_push_event (parse->srcpad, parse->pending_segment);
+      parse->pending_segment = NULL;
+    }
+  }
+
+  if (parse->priv->pending_events) {
+    GList *l;
+
+    for (l = parse->priv->pending_events; l != NULL; l = l->next) {
+      gst_pad_push_event (parse->srcpad, GST_EVENT (l->data));
+    }
+    g_list_free (parse->priv->pending_events);
+    parse->priv->pending_events = NULL;
+  }
+
+  if (GST_BUFFER_TIMESTAMP_IS_VALID (buffer))
+    last_stop = GST_BUFFER_TIMESTAMP (buffer);
+  if (last_stop != GST_CLOCK_TIME_NONE && GST_BUFFER_DURATION_IS_VALID (buffer))
+    last_stop += GST_BUFFER_DURATION (buffer);
+
+  gst_buffer_set_caps (buffer, GST_PAD_CAPS (parse->srcpad));
+
+  /* TODO: Add to seek table */
+
+  if (GST_BUFFER_TIMESTAMP_IS_VALID (buffer) &&
+      GST_CLOCK_TIME_IS_VALID (parse->segment.stop) &&
+      GST_BUFFER_TIMESTAMP (buffer) > parse->segment.stop) {
+    GST_LOG_OBJECT (parse, "Dropped frame, after segment");
+    gst_buffer_unref (buffer);
+  } else if (GST_BUFFER_TIMESTAMP_IS_VALID (buffer) &&
+      GST_BUFFER_DURATION_IS_VALID (buffer) &&
+      GST_CLOCK_TIME_IS_VALID (parse->segment.start) &&
+      GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION_IS_VALID (buffer)
+      < parse->segment.start) {
+    /* FIXME: subclass needs way to override the start as downstream might
+     * need frames before for proper decoding */
+    GST_LOG_OBJECT (parse, "Dropped frame, before segment");
+    gst_buffer_unref (buffer);
+  } else {
+    guint size = GST_BUFFER_SIZE (buffer);
+
+    ret = gst_pad_push (parse->srcpad, buffer);
+
+    GST_LOG_OBJECT (parse, "frame (%d bytes) pushed: %s", size,
+        gst_flow_get_name (ret));
+  }
+
+  /* Update current running segment position */
+  if (ret == GST_FLOW_OK && last_stop != GST_CLOCK_TIME_NONE)
+    gst_segment_set_last_stop (&parse->segment, GST_FORMAT_TIME, last_stop);
+
+  return ret;
+}
+
+/**
+ * gst_base_parse_handle_and_push_buffer:
+ * @parse: #GstBaseParse.
+ * @klass: #GstBaseParseClass.
+ * @buffer: #GstBuffer.
+ *
+ * Parses the frame from given buffer and pushes it forward. Also performs
+ * timestamp handling and checks the segment limits.
+ *
+ * This is called with srcpad STREAM_LOCK held.
+ *
+ * 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;
+  }
+
+  /* FIXME: Set upstream timestamp if possible */
+
+  ret = klass->parse_frame (parse, 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;
+  }
+
+  g_return_val_if_fail (GST_PAD_CAPS (parse->srcpad), GST_FLOW_ERROR);
+
+  ret = gst_base_parse_push_buffer (parse, buffer);
+
+  return ret;
+}
+
+
+/**
+ * gst_base_parse_drain:
+ * @parse: #GstBaseParse.
+ *
+ * Drains the adapter until it is empty. It decreases the min_frame_size to
+ * match the current adapter size and calls chain method until the adapter
+ * is emptied or chain returns with error.
+ */
+static void
+gst_base_parse_drain (GstBaseParse * parse)
+{
+  guint avail;
+
+  for (;;) {
+    avail = gst_adapter_available (parse->priv->adapter);
+    if (!avail)
+      break;
+
+    gst_base_parse_set_min_frame_size (parse, avail);
+    if (gst_base_parse_chain (parse->sinkpad, NULL) != GST_FLOW_OK) {
+      break;
+    }
+  }
+}
+
+
+/**
+ * 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;
+  gint skip = -1;
+  const guint8 *data;
+  guint min_size;
+
+  parse = GST_BASE_PARSE (GST_OBJECT_PARENT (pad));
+  bclass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  /* Make sure that adapter doesn't have any old data after
+     newsegment has been received and update our offset */
+  if (parse->pending_segment) {
+    gst_adapter_clear (parse->priv->adapter);
+    parse->priv->offset = parse->priv->pending_offset;
+  }
+
+  if (buffer) {
+    GST_LOG_OBJECT (parse, "buffer size: %d, offset = %lld",
+        GST_BUFFER_SIZE (buffer), GST_BUFFER_OFFSET (buffer));
+
+
+    gst_adapter_push (parse->priv->adapter, buffer);
+  }
+
+  /* Parse and push as many frames as possible */
+  /* Stop either when adapter is empty or we are flushing */
+  while (!parse->priv->flushing) {
+    tmpbuf = gst_buffer_new ();
+
+    /* Synchronization loop */
+    for (;;) {
+
+      GST_BASE_PARSE_LOCK (parse);
+      min_size = parse->priv->min_frame_size;
+      GST_BASE_PARSE_UNLOCK (parse);
+
+      /* Collect at least min_frame_size bytes */
+      if (gst_adapter_available (parse->priv->adapter) < min_size) {
+        GST_DEBUG_OBJECT (parse, "not enough data available (only %d bytes)",
+            gst_adapter_available (parse->priv->adapter));
+        gst_buffer_unref (tmpbuf);
+        goto done;
+      }
+
+      data = gst_adapter_peek (parse->priv->adapter, min_size);
+      GST_BUFFER_DATA (tmpbuf) = (guint8 *) data;
+      GST_BUFFER_SIZE (tmpbuf) = min_size;
+      GST_BUFFER_OFFSET (tmpbuf) = parse->priv->offset;
+      GST_BUFFER_FLAG_SET (tmpbuf, GST_MINI_OBJECT_FLAG_READONLY);
+
+      if (parse->priv->discont) {
+        GST_DEBUG_OBJECT (parse, "marking DISCONT");
+        GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+      }
+
+      skip = -1;
+      if (bclass->check_valid_frame (parse, tmpbuf, &fsize, &skip)) {
+        break;
+      }
+      if (skip > 0) {
+        GST_LOG_OBJECT (parse, "finding sync, skipping %d bytes", skip);
+        gst_adapter_flush (parse->priv->adapter, skip);
+        parse->priv->offset += skip;
+      } else if (skip == -1) {
+        /* subclass didn't touch this value. By default we skip 1 byte */
+        GST_LOG_OBJECT (parse, "finding sync, skipping 1 byte");
+        gst_adapter_flush (parse->priv->adapter, 1);
+        parse->priv->offset++;
+      }
+      /* There is a possibility that subclass set the skip value to zero.
+         This means that it has probably found a frame but wants to ask
+         more data (by increasing the min_size) to be sure of this. */
+    }
+    gst_buffer_unref (tmpbuf);
+    tmpbuf = NULL;
+
+    if (skip > 0) {
+      /* Subclass found the sync, but still wants to skip some data */
+      GST_LOG_OBJECT (parse, "skipping %d bytes", skip);
+      gst_adapter_flush (parse->priv->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->priv->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_OBJECT (parse, "push returned %d", ret);
+      break;
+    }
+  }
+
+done:
+  GST_LOG_OBJECT (parse, "chain leaving");
+  return ret;
+}
+
+static GstFlowReturn
+gst_base_parse_pull_range (GstBaseParse * parse, guint size,
+    GstBuffer ** buffer)
+{
+  GstFlowReturn ret = GST_FLOW_OK;
+
+  g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
+
+  /* Caching here actually makes much less difference than one would expect.
+   * We do it mainly to avoid pulling buffers of 1 byte all the time */
+  if (parse->priv->cache) {
+    guint64 cache_offset = GST_BUFFER_OFFSET (parse->priv->cache);
+    guint cache_size = GST_BUFFER_SIZE (parse->priv->cache);
+
+    if (cache_offset <= parse->priv->offset &&
+        (parse->priv->offset + size) < (cache_offset + cache_size)) {
+      *buffer = gst_buffer_create_sub (parse->priv->cache,
+          parse->priv->offset - cache_offset, size);
+      GST_BUFFER_OFFSET (*buffer) = parse->priv->offset;
+      return GST_FLOW_OK;
+    }
+    /* not enough data in the cache, free cache and get a new one */
+    gst_buffer_unref (parse->priv->cache);
+    parse->priv->cache = NULL;
+  }
+
+  /* refill the cache */
+  ret =
+      gst_pad_pull_range (parse->sinkpad, parse->priv->offset, MAX (size,
+          64 * 1024), &parse->priv->cache);
+  if (ret != GST_FLOW_OK) {
+    parse->priv->cache = NULL;
+    return ret;
+  }
+
+  if (GST_BUFFER_SIZE (parse->priv->cache) >= size) {
+    *buffer = gst_buffer_create_sub (parse->priv->cache, 0, size);
+    GST_BUFFER_OFFSET (*buffer) = parse->priv->offset;
+    return GST_FLOW_OK;
+  }
+
+  /* Not possible to get enough data, try a last time with
+   * requesting exactly the size we need */
+  gst_buffer_unref (parse->priv->cache);
+  parse->priv->cache = NULL;
+
+  ret = gst_pad_pull_range (parse->sinkpad, parse->priv->offset, size,
+      &parse->priv->cache);
+
+  if (ret != GST_FLOW_OK) {
+    GST_DEBUG_OBJECT (parse, "pull_range returned %d", ret);
+    *buffer = NULL;
+    return ret;
+  }
+
+  if (GST_BUFFER_SIZE (parse->priv->cache) < size) {
+    GST_WARNING_OBJECT (parse, "Dropping short buffer at offset %"
+        G_GUINT64_FORMAT ": wanted %u bytes, got %u bytes", parse->priv->offset,
+        size, GST_BUFFER_SIZE (parse->priv->cache));
+
+    gst_buffer_unref (parse->priv->cache);
+    parse->priv->cache = NULL;
+
+    *buffer = NULL;
+    return GST_FLOW_UNEXPECTED;
+  }
+
+  *buffer = gst_buffer_create_sub (parse->priv->cache, 0, size);
+  GST_BUFFER_OFFSET (*buffer) = parse->priv->offset;
+
+  return GST_FLOW_OK;
+}
+
+/**
+ * gst_base_parse_loop:
+ * @pad: GstPad
+ *
+ * Loop that is used in pull mode to retrieve data from upstream.
+ */
+static void
+gst_base_parse_loop (GstPad * pad)
+{
+  GstBaseParse *parse;
+  GstBaseParseClass *klass;
+  GstBuffer *buffer, *outbuf;
+  gboolean ret = FALSE;
+  guint fsize = 0, min_size;
+  gint skip = 0;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  /* TODO: Check if we reach segment stop limit */
+
+  while (TRUE) {
+
+    GST_BASE_PARSE_LOCK (parse);
+    min_size = parse->priv->min_frame_size;
+    GST_BASE_PARSE_UNLOCK (parse);
+
+    ret = gst_base_parse_pull_range (parse, min_size, &buffer);
+
+    if (ret == GST_FLOW_UNEXPECTED)
+      goto eos;
+    else if (ret != GST_FLOW_OK)
+      goto need_pause;
+
+    if (parse->priv->discont) {
+      GST_DEBUG_OBJECT (parse, "marking DISCONT");
+      GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+    }
+
+    skip = -1;
+    if (klass->check_valid_frame (parse, buffer, &fsize, &skip)) {
+      break;
+    }
+    if (skip > 0) {
+      GST_LOG_OBJECT (parse, "finding sync, skipping %d bytes", skip);
+      parse->priv->offset += skip;
+    } else if (skip == -1) {
+      GST_LOG_OBJECT (parse, "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_OFFSET (outbuf) = GST_BUFFER_OFFSET (buffer);
+    gst_buffer_unref (buffer);
+  } else {
+    gst_buffer_unref (buffer);
+    ret = gst_base_parse_pull_range (parse, fsize, &outbuf);
+
+    if (ret == GST_FLOW_UNEXPECTED)
+      goto eos;
+    else if (ret != GST_FLOW_OK)
+      goto need_pause;
+  }
+
+  parse->priv->offset += fsize;
+
+  /* Does the subclass want to skip too? */
+  if (skip > 0)
+    parse->priv->offset += 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 (parse->srcpad, gst_event_new_eos ());
+    }
+    goto need_pause;
+  }
+
+  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;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (sinkpad));
+
+  GST_DEBUG_OBJECT (parse, "sink activate");
+
+  if (gst_pad_check_pull_range (sinkpad)) {
+    GST_DEBUG_OBJECT (parse, "trying to activate in pull mode");
+    result = gst_pad_activate_pull (sinkpad, TRUE);
+  } else {
+    GST_DEBUG_OBJECT (parse, "trying to activate in push mode");
+    result = gst_pad_activate_push (sinkpad, TRUE);
+  }
+
+  GST_DEBUG_OBJECT (parse, "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_OBJECT (parse, "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;
+
+    if (parse->pending_segment)
+      gst_event_unref (parse->pending_segment);
+
+    parse->pending_segment =
+        gst_event_new_new_segment (FALSE, parse->segment.rate,
+        parse->segment.format,
+        parse->segment.start, parse->segment.stop, parse->segment.last_stop);
+
+    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);
+
+    g_list_foreach (parse->priv->pending_events, (GFunc) gst_mini_object_unref,
+        NULL);
+    g_list_free (parse->priv->pending_events);
+    parse->priv->pending_events = NULL;
+
+    if (parse->priv->cache) {
+      gst_buffer_unref (parse->priv->cache);
+      parse->priv->cache = NULL;
+    }
+
+    parse->priv->pad_mode = GST_ACTIVATE_NONE;
+  }
+  GST_DEBUG_OBJECT (parse, "activate: %d", result);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_sink_activate_push:
+ * @pad: #GstPad to be (de)activated.
+ * @active: TRUE when activating, FALSE when deactivating.
+ *
+ * Returns: TRUE if (de)activation succeeded.
+ */
+static gboolean
+gst_base_parse_sink_activate_push (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstBaseParse *parse;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+
+  GST_DEBUG_OBJECT (parse, "sink activate push");
+
+  result = gst_base_parse_activate (parse, active);
+
+  if (result)
+    parse->priv->pad_mode = active ? GST_ACTIVATE_PUSH : GST_ACTIVATE_NONE;
+
+  GST_DEBUG_OBJECT (parse, "sink activate push: %d", result);
+
+  gst_object_unref (parse);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_sink_activate_pull:
+ * @sinkpad: #GstPad to be (de)activated.
+ * @active: TRUE when activating, FALSE when deactivating.
+ *
+ * Returns: TRUE if (de)activation succeeded.
+ */
+static gboolean
+gst_base_parse_sink_activate_pull (GstPad * sinkpad, gboolean active)
+{
+  gboolean result = FALSE;
+  GstBaseParse *parse;
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (sinkpad));
+
+  GST_DEBUG_OBJECT (parse, "activate pull");
+
+  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_DEBUG_OBJECT (parse, "sink activate pull: %d", result);
+
+  gst_object_unref (parse);
+  return result;
+}
+
+
+/**
+ * gst_base_parse_set_duration:
+ * @parse: #GstBaseParse.
+ * @fmt: #GstFormat.
+ * @duration: duration value.
+ *
+ * Sets the duration of the currently playing media. Subclass can use this
+ * when it notices a change in the media duration.
+ */
+void
+gst_base_parse_set_duration (GstBaseParse * parse,
+    GstFormat fmt, gint64 duration)
+{
+  g_return_if_fail (parse != NULL);
+
+  GST_BASE_PARSE_LOCK (parse);
+  if (duration != parse->priv->duration) {
+    GstMessage *m;
+
+    m = gst_message_new_duration (GST_OBJECT (parse), fmt, duration);
+    gst_element_post_message (GST_ELEMENT (parse), m);
+
+    /* TODO: what about duration tag? */
+  }
+  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_LOG_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_OBJECT (parse, "position query");
+
+      gst_query_parse_position (query, &format, NULL);
+
+      g_mutex_lock (parse->parse_lock);
+
+      if (format == GST_FORMAT_BYTES) {
+        dest_value = parse->priv->offset;
+        res = TRUE;
+      } else if (format == parse->segment.format &&
+          GST_CLOCK_TIME_IS_VALID (parse->segment.last_stop)) {
+        dest_value = parse->segment.last_stop;
+        res = TRUE;
+      } else {
+        /* priv->offset is updated in both PUSH/PULL modes */
+        res = klass->convert (parse, GST_FORMAT_BYTES, parse->priv->offset,
+            format, &dest_value);
+      }
+      g_mutex_unlock (parse->parse_lock);
+
+      if (res)
+        gst_query_set_position (query, format, dest_value);
+      else
+        res = gst_pad_query_default (pad, query);
+
+      break;
+    }
+    case GST_QUERY_DURATION:
+    {
+      GstFormat format;
+      gint64 dest_value;
+
+      GST_DEBUG_OBJECT (parse, "duration query");
+
+      gst_query_parse_duration (query, &format, NULL);
+
+      g_mutex_lock (parse->parse_lock);
+
+      if (format == GST_FORMAT_BYTES) {
+        res = gst_pad_query_peer_duration (parse->sinkpad, &format,
+            &dest_value);
+      } else if (parse->priv->duration != -1 &&
+          format == parse->priv->duration_fmt) {
+        dest_value = parse->priv->duration;
+        res = TRUE;
+      } else if (parse->priv->duration != -1) {
+        res = klass->convert (parse, parse->priv->duration_fmt,
+            parse->priv->duration, format, &dest_value);
+      }
+
+      g_mutex_unlock (parse->parse_lock);
+
+      if (res)
+        gst_query_set_duration (query, format, dest_value);
+      else
+        res = gst_pad_query_default (pad, query);
+      break;
+    }
+    case GST_QUERY_SEEKING:
+    {
+      GstFormat fmt;
+      gboolean seekable = FALSE;
+
+      GST_DEBUG_OBJECT (parse, "seeking query");
+
+      gst_query_parse_seeking (query, &fmt, NULL, NULL, NULL);
+
+      if (fmt != GST_FORMAT_TIME) {
+        return gst_pad_query_default (pad, query);
+      }
+
+      seekable = klass->is_seekable (parse);
+
+      /* TODO: could this duration be calculated/converted if subclass
+         hasn't given it? */
+      gst_query_set_seeking (query, GST_FORMAT_TIME, seekable, 0,
+          (parse->priv->duration == -1) ?
+          GST_CLOCK_TIME_NONE : parse->priv->duration);
+
+      GST_DEBUG_OBJECT (parse, "seekable: %d", seekable);
+      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);
+
+      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, };
+  GstFormat dstformat;
+
+  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;
+
+  dstformat = GST_FORMAT_BYTES;
+  if (!gst_pad_query_convert (parse->srcpad, format, cur, &dstformat, &seekpos)) {
+    GST_DEBUG_OBJECT (parse, "conversion failed");
+    return FALSE;
+  }
+
+  GST_DEBUG_OBJECT (parse, "seek position %lld in bytes: %lld", cur, seekpos);
+
+  if (parse->priv->pad_mode == GST_ACTIVATE_PULL) {
+    gint64 last_stop;
+
+    GST_DEBUG_OBJECT (parse, "seek in PULL mode");
+
+    if (flush) {
+      if (parse->srcpad) {
+        GST_DEBUG_OBJECT (parse, "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_OBJECT (parse, "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_OBJECT (parse, "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_OBJECT (parse, "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_OBJECT (parse,
+          "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 {
+    GstEvent *new_event;
+    /* 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_OBJECT (parse, "seek in PUSH mode");
+    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_OBJECT (parse, "negative playback rates are not supported yet.");
+    res = FALSE;
+    goto done;
+  }
+wrong_type:
+  {
+    GST_DEBUG_OBJECT (parse, "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);
+  g_free (caps_str);
+
+  parse = GST_BASE_PARSE (gst_pad_get_parent (pad));
+  klass = GST_BASE_PARSE_GET_CLASS (parse);
+
+  GST_DEBUG_OBJECT (parse, "setcaps: %s", caps_str);
+
+  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);
+}