gstreamer_core/libs/gst/base/gstbasetransform.c
changeset 0 0e761a78d257
child 8 4a7fac7dd34a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/libs/gst/base/gstbasetransform.c	Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,2023 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2000 Wim Taymans <wtay@chello.be>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *                    2005 Andy Wingo <wingo@fluendo.com>
+ *                    2005 Thomas Vander Stichele <thomas at apestaart dot org>
+ *
+ * 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:gstbasetransform
+ * @short_description: Base class for simple transform filters
+ * @see_also: #GstBaseSrc, #GstBaseSink
+ *
+ * This base class is for filter elements that process data.
+ *
+ * It provides for:
+ * <itemizedlist>
+ *   <listitem><para>one sinkpad and one srcpad</para></listitem>
+ *   <listitem><para>
+ *      Possible formats on sink and source pad implemented
+ *      with custom transform_caps function. By default uses
+ *      same format on sink and source.
+ *   </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 if the sub-class transform can operate on arbitrary data
+ *    </para></listitem>
+ * </itemizedlist>
+ *
+ * Use Cases:
+ * <orderedlist>
+ * <listitem>
+ *   <itemizedlist><title>Passthrough mode</title>
+ *   <listitem><para>
+ *     Element has no interest in modifying the buffer. It may want to inspect it,
+ *     in which case the element should have a transform_ip function. If there
+ *     is no transform_ip function in passthrough mode, the buffer is pushed
+ *     intact.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     On the GstBaseTransformClass is the passthrough_on_same_caps variable
+ *     which will automatically set/unset passthrough based on whether the
+ *     element negotiates the same caps on both pads.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     passthrough_on_same_caps on an element that doesn't implement a
+ *     transform_caps function is useful for elements that only inspect data
+ *     (such as level)
+ *   </para></listitem>
+ *   </itemizedlist>
+ *   <itemizedlist>
+ *   <title>Example elements</title>
+ *     <listitem>Level</listitem>
+ *     <listitem>Videoscale, audioconvert, ffmpegcolorspace, audioresample in
+ *     certain modes.</listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * <listitem>
+ *   <itemizedlist>
+ *     <title>Modifications in-place - input buffer and output buffer are the
+ *     same thing.</title>
+ *   <listitem><para>
+ *     The element must implement a transform_ip function.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     Output buffer size must <= input buffer size
+ *   </para></listitem>
+ *   <listitem><para>
+ *     If the always_in_place flag is set, non-writable buffers will be copied
+ *     and passed to the transform_ip function, otherwise a new buffer will be
+ *     created and the transform function called.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     Incoming writable buffers will be passed to the transform_ip function
+ *     immediately.  </para></listitem>
+ *   <listitem><para>
+ *     only implementing transform_ip and not transform implies always_in_place
+ *     = TRUE
+ *   </para></listitem>
+ *   </itemizedlist>
+ *   <itemizedlist>
+ *   <title>Example elements</title>
+ *     <listitem>Volume</listitem>
+ *     <listitem>Audioconvert in certain modes (signed/unsigned
+ *     conversion)</listitem>
+ *     <listitem>ffmpegcolorspace in certain modes (endianness
+ *     swapping)</listitem>
+ *   </itemizedlist>
+ *  </listitem>
+ * <listitem>
+ *   <itemizedlist>
+ *   <title>Modifications only to the caps/metadata of a buffer</title>
+ *   <listitem><para>
+ *     The element does not require writable data, but non-writable buffers
+ *     should be subbuffered so that the meta-information can be replaced.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     Elements wishing to operate in this mode should replace the
+ *     prepare_output_buffer method to create subbuffers of the input buffer
+ *     and set always_in_place to TRUE
+ *   </para></listitem>
+ *   </itemizedlist>
+ *   <itemizedlist>
+ *   <title>Example elements</title>
+ *     <listitem>Capsfilter when setting caps on outgoing buffers that have
+ *     none.</listitem>
+ *     <listitem>identity when it is going to re-timestamp buffers by
+ *     datarate.</listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * <listitem>
+ *   <itemizedlist><title>Normal mode</title>
+ *   <listitem><para>
+ *     always_in_place flag is not set, or there is no transform_ip function
+ *   </para></listitem>
+ *   <listitem><para>
+ *     Element will receive an input buffer and output buffer to operate on.
+ *   </para></listitem>
+ *   <listitem><para>
+ *     Output buffer is allocated by calling the prepare_output_buffer function.
+ *   </para></listitem>
+ *   </itemizedlist>
+ *   <itemizedlist>
+ *   <title>Example elements</title>
+ *     <listitem>Videoscale, ffmpegcolorspace, audioconvert when doing
+ *     scaling/conversions</listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * <listitem>
+ *   <itemizedlist><title>Special output buffer allocations</title>
+ *   <listitem><para>
+ *     Elements which need to do special allocation of their output buffers
+ *     other than what gst_buffer_pad_alloc allows should implement a
+ *     prepare_output_buffer method, which calls the parent implementation and
+ *     passes the newly allocated buffer.
+ *   </para></listitem>
+ *   </itemizedlist>
+ *   <itemizedlist>
+ *   <title>Example elements</title>
+ *     <listitem>efence</listitem>
+ *   </itemizedlist>
+ * </listitem>
+ * </orderedlist>
+ *
+ * <itemizedlist><title>Sub-class settable flags on GstBaseTransform</title>
+ * <listitem><para>
+ *   <itemizedlist><title>passthrough</title>
+ *     <listitem><para>
+ *       Implies that in the current configuration, the sub-class is not
+ *       interested in modifying the buffers.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       Elements which are always in passthrough mode whenever the same caps
+ *       has been negotiated on both pads can set the class variable
+ *       passthrough_on_same_caps to have this behaviour automatically.
+ *     </para></listitem>
+ *   </itemizedlist>
+ * </para></listitem>
+ * <listitem><para>
+ *   <itemizedlist><title>always_in_place</title>
+ *     <listitem><para>
+ *       Determines whether a non-writable buffer will be copied before passing
+ *       to the transform_ip function.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       Implied TRUE if no transform function is implemented.
+ *     </para></listitem>
+ *     <listitem><para>
+ *       Implied FALSE if ONLY transform function is implemented.
+ *     </para></listitem>
+ *   </itemizedlist>
+ * </para></listitem>
+ * </itemizedlist>
+ *
+*/
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#ifdef __SYMBIAN32__
+#include <gst_global.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+
+#include "../../../gst/gst_private.h"
+#include "../../../gst/gst-i18n-lib.h"
+#include "gstbasetransform.h"
+#include <gst/gstmarshal.h>
+
+#ifdef __SYMBIAN32__
+#include <glib_global.h>
+#include <gobject_global.h>
+#endif
+GST_DEBUG_CATEGORY_STATIC (gst_base_transform_debug);
+#ifndef __SYMBIAN32__
+#define GST_CAT_DEFAULT gst_base_transform_debug
+#endif
+
+/* BaseTransform signals and args */
+enum
+{
+  /* FILL ME */
+  LAST_SIGNAL
+};
+
+#define DEFAULT_PROP_QOS	FALSE
+
+enum
+{
+  PROP_0,
+  PROP_QOS
+};
+
+#define GST_BASE_TRANSFORM_GET_PRIVATE(obj)  \
+    (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BASE_TRANSFORM, GstBaseTransformPrivate))
+
+struct _GstBaseTransformPrivate
+{
+  /* QoS *//* with LOCK */
+  gboolean qos_enabled;
+  gdouble proportion;
+  GstClockTime earliest_time;
+  /* previous buffer had a discont */
+  gboolean discont;
+
+  GstActivateMode pad_mode;
+
+  gboolean gap_aware;
+};
+
+static GstElementClass *parent_class = NULL;
+
+static void gst_base_transform_class_init (GstBaseTransformClass * klass);
+static void gst_base_transform_init (GstBaseTransform * trans,
+    GstBaseTransformClass * klass);
+static GstFlowReturn gst_base_transform_prepare_output_buffer (GstBaseTransform
+    * trans, GstBuffer * input, gint size, GstCaps * caps, GstBuffer ** buf);
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+GType
+gst_base_transform_get_type (void)
+{
+  static GType base_transform_type = 0;
+
+  if (!base_transform_type) {
+    static const GTypeInfo base_transform_info = {
+      sizeof (GstBaseTransformClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_base_transform_class_init,
+      NULL,
+      NULL,
+      sizeof (GstBaseTransform),
+      0,
+      (GInstanceInitFunc) gst_base_transform_init,
+    };
+
+    base_transform_type = g_type_register_static (GST_TYPE_ELEMENT,
+        "GstBaseTransform", &base_transform_info, G_TYPE_FLAG_ABSTRACT);
+  }
+  return base_transform_type;
+}
+
+static void gst_base_transform_finalize (GObject * object);
+static void gst_base_transform_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_base_transform_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static gboolean gst_base_transform_src_activate_pull (GstPad * pad,
+    gboolean active);
+static gboolean gst_base_transform_sink_activate_push (GstPad * pad,
+    gboolean active);
+static gboolean gst_base_transform_activate (GstBaseTransform * trans,
+    gboolean active);
+static gboolean gst_base_transform_get_unit_size (GstBaseTransform * trans,
+    GstCaps * caps, guint * size);
+
+static gboolean gst_base_transform_src_event (GstPad * pad, GstEvent * event);
+static gboolean gst_base_transform_src_eventfunc (GstBaseTransform * trans,
+    GstEvent * event);
+static gboolean gst_base_transform_sink_event (GstPad * pad, GstEvent * event);
+static gboolean gst_base_transform_sink_eventfunc (GstBaseTransform * trans,
+    GstEvent * event);
+static gboolean gst_base_transform_check_get_range (GstPad * pad);
+static GstFlowReturn gst_base_transform_getrange (GstPad * pad, guint64 offset,
+    guint length, GstBuffer ** buffer);
+static GstFlowReturn gst_base_transform_chain (GstPad * pad,
+    GstBuffer * buffer);
+static GstCaps *gst_base_transform_getcaps (GstPad * pad);
+static gboolean gst_base_transform_setcaps (GstPad * pad, GstCaps * caps);
+static GstFlowReturn gst_base_transform_buffer_alloc (GstPad * pad,
+    guint64 offset, guint size, GstCaps * caps, GstBuffer ** buf);
+
+/* static guint gst_base_transform_signals[LAST_SIGNAL] = { 0 }; */
+
+static void
+gst_base_transform_finalize (GObject * object)
+{
+  GstBaseTransform *trans;
+
+  trans = GST_BASE_TRANSFORM (object);
+
+  g_mutex_free (trans->transform_lock);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_base_transform_class_init (GstBaseTransformClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+
+  GST_DEBUG_CATEGORY_INIT (gst_base_transform_debug, "basetransform", 0,
+      "basetransform element");
+
+  g_type_class_add_private (klass, sizeof (GstBaseTransformPrivate));
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gobject_class->set_property =
+      GST_DEBUG_FUNCPTR (gst_base_transform_set_property);
+  gobject_class->get_property =
+      GST_DEBUG_FUNCPTR (gst_base_transform_get_property);
+
+  g_object_class_install_property (gobject_class, PROP_QOS,
+      g_param_spec_boolean ("qos", "QoS", "Handle Quality-of-Service events",
+          DEFAULT_PROP_QOS, G_PARAM_READWRITE));
+
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_base_transform_finalize);
+
+  klass->passthrough_on_same_caps = FALSE;
+  klass->event = GST_DEBUG_FUNCPTR (gst_base_transform_sink_eventfunc);
+  klass->src_event = GST_DEBUG_FUNCPTR (gst_base_transform_src_eventfunc);
+}
+
+static void
+gst_base_transform_init (GstBaseTransform * trans,
+    GstBaseTransformClass * bclass)
+{
+  GstPadTemplate *pad_template;
+
+  GST_DEBUG ("gst_base_transform_init");
+
+  trans->priv = GST_BASE_TRANSFORM_GET_PRIVATE (trans);
+
+  pad_template =
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (bclass), "sink");
+  g_return_if_fail (pad_template != NULL);
+  trans->sinkpad = gst_pad_new_from_template (pad_template, "sink");
+  gst_pad_set_getcaps_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_getcaps));
+  gst_pad_set_setcaps_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_setcaps));
+  gst_pad_set_event_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_sink_event));
+  gst_pad_set_chain_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_chain));
+  gst_pad_set_activatepush_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_sink_activate_push));
+  gst_pad_set_bufferalloc_function (trans->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_buffer_alloc));
+  gst_element_add_pad (GST_ELEMENT (trans), trans->sinkpad);
+
+  pad_template =
+      gst_element_class_get_pad_template (GST_ELEMENT_CLASS (bclass), "src");
+  g_return_if_fail (pad_template != NULL);
+  trans->srcpad = gst_pad_new_from_template (pad_template, "src");
+  gst_pad_set_getcaps_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_getcaps));
+  gst_pad_set_setcaps_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_setcaps));
+  gst_pad_set_event_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_src_event));
+  gst_pad_set_checkgetrange_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_check_get_range));
+  gst_pad_set_getrange_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_getrange));
+  gst_pad_set_activatepull_function (trans->srcpad,
+      GST_DEBUG_FUNCPTR (gst_base_transform_src_activate_pull));
+  gst_element_add_pad (GST_ELEMENT (trans), trans->srcpad);
+
+  trans->transform_lock = g_mutex_new ();
+  trans->delay_configure = FALSE;
+  trans->pending_configure = FALSE;
+  trans->priv->qos_enabled = DEFAULT_PROP_QOS;
+  trans->cache_caps1 = NULL;
+  trans->cache_caps2 = NULL;
+  trans->priv->pad_mode = GST_ACTIVATE_NONE;
+  trans->priv->gap_aware = FALSE;
+
+  trans->passthrough = FALSE;
+  if (bclass->transform == NULL) {
+    /* If no transform function, always_in_place is TRUE */
+    GST_DEBUG_OBJECT (trans, "setting in_place TRUE");
+    trans->always_in_place = TRUE;
+
+    if (bclass->transform_ip == NULL)
+      trans->passthrough = TRUE;
+  }
+}
+
+/* given @caps on the src or sink pad (given by @direction)
+ * calculate the possible caps on the other pad.
+ *
+ * Returns new caps, unref after usage.
+ */
+static GstCaps *
+gst_base_transform_transform_caps (GstBaseTransform * trans,
+    GstPadDirection direction, GstCaps * caps)
+{
+  GstCaps *ret;
+  GstBaseTransformClass *klass;
+
+  klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  /* if there is a custom transform function, use this */
+  if (klass->transform_caps) {
+    GstCaps *temp;
+    gint i;
+
+    /* start with empty caps */
+    ret = gst_caps_new_empty ();
+    GST_DEBUG_OBJECT (trans, "transform caps (direction = %d)", direction);
+
+    if (gst_caps_is_any (caps)) {
+      /* for any caps we still have to call the transform function */
+      GST_DEBUG_OBJECT (trans, "from: ANY");
+      temp = klass->transform_caps (trans, direction, caps);
+      GST_DEBUG_OBJECT (trans, "  to: %" GST_PTR_FORMAT, temp);
+
+      temp = gst_caps_make_writable (temp);
+      gst_caps_append (ret, temp);
+    } else {
+      /* we send caps with just one structure to the transform
+       * function as this is easier for the element */
+      for (i = 0; i < gst_caps_get_size (caps); i++) {
+        GstCaps *nth;
+
+        nth = gst_caps_copy_nth (caps, i);
+        GST_DEBUG_OBJECT (trans, "from[%d]: %" GST_PTR_FORMAT, i, nth);
+        temp = klass->transform_caps (trans, direction, nth);
+        gst_caps_unref (nth);
+        GST_DEBUG_OBJECT (trans, "  to[%d]: %" GST_PTR_FORMAT, i, temp);
+
+        temp = gst_caps_make_writable (temp);
+        /* FIXME: here we need to only append those structures, that are not yet
+         * in there
+         * gst_caps_append (ret, temp);
+         */
+        gst_caps_merge (ret, temp);
+      }
+      GST_DEBUG_OBJECT (trans, "merged: (%d)", gst_caps_get_size (ret));
+      /* now simplify caps
+         gst_caps_do_simplify (ret);
+         GST_DEBUG_OBJECT (trans, "simplified: (%d)", gst_caps_get_size (ret));
+       */
+    }
+  } else {
+    /* else use the identity transform */
+    ret = gst_caps_ref (caps);
+  }
+
+  GST_DEBUG_OBJECT (trans, "to: (%d) %" GST_PTR_FORMAT, gst_caps_get_size (ret),
+      ret);
+
+  return ret;
+}
+
+static gboolean
+gst_base_transform_transform_size (GstBaseTransform * trans,
+    GstPadDirection direction, GstCaps * caps,
+    guint size, GstCaps * othercaps, guint * othersize)
+{
+  guint inunitsize, outunitsize, units;
+  GstBaseTransformClass *klass;
+  gboolean ret;
+
+  klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  GST_DEBUG_OBJECT (trans, "asked to transform size %d for caps %"
+      GST_PTR_FORMAT " to size for caps %" GST_PTR_FORMAT " in direction %s",
+      size, caps, othercaps, direction == GST_PAD_SRC ? "SRC" : "SINK");
+
+  /* if there is a custom transform function, use this */
+  if (klass->transform_size) {
+    ret = klass->transform_size (trans, direction, caps, size, othercaps,
+        othersize);
+  } else {
+    if (!gst_base_transform_get_unit_size (trans, caps, &inunitsize))
+      goto no_in_size;
+
+    GST_DEBUG_OBJECT (trans, "input size %d, input unit size %d", size,
+        inunitsize);
+
+    if (inunitsize == 0 || (size % inunitsize != 0))
+      goto no_multiple;
+
+    units = size / inunitsize;
+    if (!gst_base_transform_get_unit_size (trans, othercaps, &outunitsize))
+      goto no_out_size;
+
+    *othersize = units * outunitsize;
+    GST_DEBUG_OBJECT (trans, "transformed size to %d", *othersize);
+
+    ret = TRUE;
+  }
+  return ret;
+
+  /* ERRORS */
+no_in_size:
+  {
+    GST_DEBUG_OBJECT (trans, "could not get in_size");
+    g_warning ("%s: could not get in_size", GST_ELEMENT_NAME (trans));
+    return FALSE;
+  }
+no_multiple:
+  {
+    GST_DEBUG_OBJECT (trans, "Size %u is not a multiple of unit size %u", size,
+        inunitsize);
+    g_warning ("%s: size %u is not a multiple of unit size %u",
+        GST_ELEMENT_NAME (trans), size, inunitsize);
+    return FALSE;
+  }
+no_out_size:
+  {
+    GST_DEBUG_OBJECT (trans, "could not get out_size");
+    g_warning ("%s: could not get out_size", GST_ELEMENT_NAME (trans));
+    return FALSE;
+  }
+}
+
+static GstCaps *
+gst_base_transform_getcaps (GstPad * pad)
+{
+  GstBaseTransform *trans;
+  GstPad *otherpad;
+  GstCaps *caps;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  otherpad = (pad == trans->srcpad) ? trans->sinkpad : trans->srcpad;
+
+  /* we can do what the peer can */
+  caps = gst_pad_peer_get_caps (otherpad);
+  if (caps) {
+    GstCaps *temp;
+    const GstCaps *templ;
+
+    GST_DEBUG_OBJECT (pad, "peer caps  %" GST_PTR_FORMAT, caps);
+
+    /* filtered against our padtemplate */
+    templ = gst_pad_get_pad_template_caps (otherpad);
+    GST_DEBUG_OBJECT (pad, "our template  %" GST_PTR_FORMAT, templ);
+    temp = gst_caps_intersect (caps, templ);
+    GST_DEBUG_OBJECT (pad, "intersected %" GST_PTR_FORMAT, temp);
+    gst_caps_unref (caps);
+    /* then see what we can transform this to */
+    caps = gst_base_transform_transform_caps (trans,
+        GST_PAD_DIRECTION (otherpad), temp);
+    GST_DEBUG_OBJECT (pad, "transformed  %" GST_PTR_FORMAT, caps);
+    gst_caps_unref (temp);
+    if (caps == NULL)
+      goto done;
+
+    /* and filter against the template again */
+    templ = gst_pad_get_pad_template_caps (pad);
+    GST_DEBUG_OBJECT (pad, "our template  %" GST_PTR_FORMAT, templ);
+    temp = gst_caps_intersect (caps, templ);
+    GST_DEBUG_OBJECT (pad, "intersected %" GST_PTR_FORMAT, temp);
+    gst_caps_unref (caps);
+    /* this is what we can do */
+    caps = temp;
+  } else {
+    /* no peer, our padtemplate is enough then */
+    caps = gst_caps_copy (gst_pad_get_pad_template_caps (pad));
+  }
+
+done:
+  GST_DEBUG_OBJECT (trans, "returning  %" GST_PTR_FORMAT, caps);
+
+  gst_object_unref (trans);
+
+  return caps;
+}
+
+/* function triggered when the in and out caps are negotiated and need
+ * to be configured in the subclass. */
+static gboolean
+gst_base_transform_configure_caps (GstBaseTransform * trans, GstCaps * in,
+    GstCaps * out)
+{
+  gboolean ret = TRUE;
+  GstBaseTransformClass *klass;
+
+  klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  /* clear the cache */
+  gst_caps_replace (&trans->cache_caps1, NULL);
+  gst_caps_replace (&trans->cache_caps2, NULL);
+
+  /* If we've a transform_ip method and same input/output caps, set in_place
+   * by default. If for some reason the sub-class prefers using a transform
+   * function, it can clear the in place flag in the set_caps */
+  gst_base_transform_set_in_place (trans,
+      klass->transform_ip && trans->have_same_caps);
+
+  /* Set the passthrough if the class wants passthrough_on_same_caps
+   * and we have the same caps on each pad */
+  if (klass->passthrough_on_same_caps)
+    gst_base_transform_set_passthrough (trans, trans->have_same_caps);
+
+  /* now configure the element with the caps */
+  if (klass->set_caps) {
+    GST_DEBUG_OBJECT (trans, "Calling set_caps method to setup caps");
+    ret = klass->set_caps (trans, in, out);
+  }
+
+  trans->negotiated = ret;
+
+  return ret;
+}
+
+/* called when new caps arrive on the sink or source pad */
+static gboolean
+gst_base_transform_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstBaseTransform *trans;
+  GstBaseTransformClass *klass;
+  GstPad *otherpad, *otherpeer;
+  GstCaps *othercaps = NULL;
+  gboolean ret = TRUE;
+  gboolean peer_checked = FALSE;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+  klass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  otherpad = (pad == trans->srcpad) ? trans->sinkpad : trans->srcpad;
+  otherpeer = gst_pad_get_peer (otherpad);
+
+  /* if we get called recursively, we bail out now to avoid an
+   * infinite loop. */
+  if (GST_PAD_IS_IN_SETCAPS (otherpad))
+    goto done;
+
+  /* caps must be fixed here */
+  if (!gst_caps_is_fixed (caps))
+    goto unfixed_caps;
+
+  /* see how we can transform the input caps. */
+  othercaps = gst_base_transform_transform_caps (trans,
+      GST_PAD_DIRECTION (pad), caps);
+
+  /* The caps we can actually output is the intersection of the transformed
+   * caps with the pad template for the pad */
+  if (othercaps) {
+    GstCaps *intersect;
+    const GstCaps *templ_caps;
+
+    templ_caps = gst_pad_get_pad_template_caps (otherpad);
+    intersect = gst_caps_intersect (othercaps, templ_caps);
+
+    gst_caps_unref (othercaps);
+    othercaps = intersect;
+  }
+
+  /* check if transform is empty */
+  if (!othercaps || gst_caps_is_empty (othercaps))
+    goto no_transform;
+
+  /* if the othercaps are not fixed, we need to fixate them, first attempt
+   * is by attempting passthrough if the othercaps are a superset of caps. */
+  if (!gst_caps_is_fixed (othercaps)) {
+    GstCaps *temp;
+
+    GST_DEBUG_OBJECT (trans,
+        "transform returned non fixed  %" GST_PTR_FORMAT, othercaps);
+
+    /* see if the target caps are a superset of the source caps, in this
+     * case we can try to perform passthrough */
+    temp = gst_caps_intersect (othercaps, caps);
+    GST_DEBUG_OBJECT (trans, "intersect returned %" GST_PTR_FORMAT, temp);
+    if (temp) {
+      if (!gst_caps_is_empty (temp) && otherpeer) {
+        GST_DEBUG_OBJECT (trans, "try passthrough with %" GST_PTR_FORMAT, caps);
+        /* try passthrough. we know it's fixed, because caps is fixed */
+        if (gst_pad_accept_caps (otherpeer, caps)) {
+          GST_DEBUG_OBJECT (trans, "peer accepted %" GST_PTR_FORMAT, caps);
+          /* peer accepted unmodified caps, we free the original non-fixed
+           * caps and work with the passthrough caps */
+          gst_caps_unref (othercaps);
+          othercaps = gst_caps_ref (caps);
+          /* mark that we checked othercaps with the peer, this
+           * makes sure we don't call accept_caps again with these same
+           * caps */
+          peer_checked = TRUE;
+        } else {
+          GST_DEBUG_OBJECT (trans,
+              "peer did not accept %" GST_PTR_FORMAT, caps);
+        }
+      }
+      gst_caps_unref (temp);
+    }
+  }
+
+  /* second attempt at fixation is done by intersecting with
+   * the peer caps */
+  if (!gst_caps_is_fixed (othercaps) && otherpeer) {
+    /* intersect against what the peer can do */
+    GstCaps *peercaps;
+    GstCaps *intersect;
+
+    GST_DEBUG_OBJECT (trans, "othercaps now %" GST_PTR_FORMAT, othercaps);
+
+    peercaps = gst_pad_get_caps (otherpeer);
+    intersect = gst_caps_intersect (peercaps, othercaps);
+    gst_caps_unref (peercaps);
+    gst_caps_unref (othercaps);
+    othercaps = intersect;
+    peer_checked = FALSE;
+
+    GST_DEBUG_OBJECT (trans,
+        "filtering against peer yields %" GST_PTR_FORMAT, othercaps);
+  }
+
+  if (gst_caps_is_empty (othercaps))
+    goto no_transform_possible;
+
+  /* third attempt at fixation, call the fixate vmethod and
+   * ultimately call the pad fixate function. */
+  if (!gst_caps_is_fixed (othercaps)) {
+    GstCaps *temp;
+
+    GST_DEBUG_OBJECT (trans,
+        "trying to fixate %" GST_PTR_FORMAT " on pad %s:%s",
+        othercaps, GST_DEBUG_PAD_NAME (otherpad));
+
+    /* since we have no other way to fixate left, we might as well just take
+     * the first of the caps list and fixate that */
+
+    /* FIXME: when fixating using the vmethod, it might make sense to fixate
+     * each of the caps; but Wim doesn't see a use case for that yet */
+    temp = gst_caps_copy_nth (othercaps, 0);
+    gst_caps_unref (othercaps);
+    othercaps = temp;
+    peer_checked = FALSE;
+
+    if (klass->fixate_caps) {
+      GST_DEBUG_OBJECT (trans, "trying to fixate %" GST_PTR_FORMAT
+          " using caps %" GST_PTR_FORMAT
+          " on pad %s:%s using fixate_caps vmethod", othercaps, caps,
+          GST_DEBUG_PAD_NAME (otherpad));
+      klass->fixate_caps (trans, GST_PAD_DIRECTION (pad), caps, othercaps);
+    }
+    /* if still not fixed, no other option but to let the default pad fixate
+     * function do its job */
+    if (!gst_caps_is_fixed (othercaps)) {
+      GST_DEBUG_OBJECT (trans, "trying to fixate %" GST_PTR_FORMAT
+          " on pad %s:%s using gst_pad_fixate_caps", othercaps,
+          GST_DEBUG_PAD_NAME (otherpad));
+      gst_pad_fixate_caps (otherpad, othercaps);
+    }
+    GST_DEBUG_OBJECT (trans, "after fixating %" GST_PTR_FORMAT, othercaps);
+  }
+
+  /* caps should be fixed now, if not we have to fail. */
+  if (!gst_caps_is_fixed (othercaps))
+    goto could_not_fixate;
+
+  /* and peer should accept, don't check again if we already checked the
+   * othercaps against the peer. */
+  if (!peer_checked && otherpeer && !gst_pad_accept_caps (otherpeer, othercaps))
+    goto peer_no_accept;
+
+  GST_DEBUG_OBJECT (trans, "Input caps were %" GST_PTR_FORMAT
+      ", and got final caps %" GST_PTR_FORMAT, caps, othercaps);
+
+  trans->have_same_caps = gst_caps_is_equal (caps, othercaps);
+  GST_DEBUG_OBJECT (trans, "have_same_caps: %d", trans->have_same_caps);
+
+  /* see if we have to configure the element now */
+  if (!trans->delay_configure) {
+    GstCaps *incaps, *outcaps;
+
+    /* make sure in and out caps are correct */
+    if (pad == trans->sinkpad) {
+      incaps = caps;
+      outcaps = othercaps;
+    } else {
+      incaps = othercaps;
+      outcaps = caps;
+    }
+    /* call configure now */
+    if (!(ret = gst_base_transform_configure_caps (trans, incaps, outcaps)))
+      goto failed_configure;
+  } else {
+    /* set pending configure, the configure will happen later with the
+     * caps we set on the pads above. */
+    trans->pending_configure = TRUE;
+  }
+
+  /* we know this will work, we implement the setcaps */
+  gst_pad_set_caps (otherpad, othercaps);
+
+  if (pad == trans->srcpad && trans->priv->pad_mode == GST_ACTIVATE_PULL) {
+    ret &= gst_pad_set_caps (otherpeer, othercaps);
+    if (!ret) {
+      GST_INFO_OBJECT (trans, "otherpeer setcaps(%" GST_PTR_FORMAT ") failed",
+          othercaps);
+    }
+  }
+
+done:
+  if (otherpeer)
+    gst_object_unref (otherpeer);
+  if (othercaps)
+    gst_caps_unref (othercaps);
+
+  trans->negotiated = ret;
+
+  gst_object_unref (trans);
+
+  return ret;
+
+  /* ERRORS */
+unfixed_caps:
+  {
+    GST_DEBUG_OBJECT (trans, "caps are not fixed  %" GST_PTR_FORMAT, caps);
+    ret = FALSE;
+    goto done;
+  }
+no_transform:
+  {
+    GST_DEBUG_OBJECT (trans,
+        "transform returned useless  %" GST_PTR_FORMAT, othercaps);
+    ret = FALSE;
+    goto done;
+  }
+no_transform_possible:
+  {
+    GST_DEBUG_OBJECT (trans,
+        "transform could not transform %" GST_PTR_FORMAT
+        " in anything we support", caps);
+    ret = FALSE;
+    goto done;
+  }
+could_not_fixate:
+  {
+    GST_ERROR_OBJECT (trans, "FAILED to fixate %" GST_PTR_FORMAT, othercaps);
+    ret = FALSE;
+    goto done;
+  }
+peer_no_accept:
+  {
+    GST_DEBUG_OBJECT (trans, "FAILED to get peer of %" GST_PTR_FORMAT
+        " to accept %" GST_PTR_FORMAT, otherpad, othercaps);
+    ret = FALSE;
+    goto done;
+  }
+failed_configure:
+  {
+    GST_DEBUG_OBJECT (trans, "FAILED to configure caps %" GST_PTR_FORMAT
+        " to accept %" GST_PTR_FORMAT, otherpad, othercaps);
+    ret = FALSE;
+    goto done;
+  }
+}
+
+/* Allocate a buffer using gst_pad_alloc_buffer
+ *
+ * This function does not do renegotiation on the source pad
+ *
+ * The output buffer is always writable. outbuf can be equal to
+ * inbuf, the caller should be prepared for this and perform 
+ * appropriate refcounting.
+ */
+static GstFlowReturn
+gst_base_transform_prepare_output_buffer (GstBaseTransform * trans,
+    GstBuffer * in_buf, gint out_size, GstCaps * out_caps, GstBuffer ** out_buf)
+{
+  GstBaseTransformClass *bclass;
+  GstFlowReturn ret = GST_FLOW_OK;
+  gboolean copy_inbuf = FALSE;
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  /* we cannot reconfigure the element yet as we are still processing
+   * the old buffer. We will therefore delay the reconfiguration of the
+   * element until we have processed this last buffer. */
+  trans->delay_configure = TRUE;
+
+  /* out_caps is the caps of the src pad gathered through the GST_PAD_CAPS 
+     macro. If a set_caps occurs during this function this caps will become
+     invalid. We want to keep them during preparation of the output buffer. */
+  if (out_caps)
+    gst_caps_ref (out_caps);
+
+  /* see if the subclass wants to alloc a buffer */
+  if (bclass->prepare_output_buffer) {
+    ret =
+        bclass->prepare_output_buffer (trans, in_buf, out_size, out_caps,
+        out_buf);
+    if (ret != GST_FLOW_OK)
+      goto done;
+
+    /* decrease refcount again if vmethod returned refcounted in_buf. This
+     * is because we need to make sure that the buffer is writable for the
+     * in_place transform. The docs of the vmethod say that you should return
+     * a reffed inbuf, which is exactly what we don't want :), oh well.. */
+    if (in_buf == *out_buf)
+      gst_buffer_unref (in_buf);
+  }
+
+  /* See if we want to prepare the buffer for in place output */
+  if (*out_buf == NULL && GST_BUFFER_SIZE (in_buf) == out_size
+      && bclass->transform_ip) {
+    if (gst_buffer_is_writable (in_buf)) {
+      if (trans->have_same_caps) {
+        /* Input buffer is already writable and caps are the same, return input as
+         * output buffer. We don't take an additional ref since that would make the
+         * output buffer not writable anymore. Caller should be prepared to deal
+         * with proper refcounting of input/output buffers. */
+        *out_buf = in_buf;
+        GST_LOG_OBJECT (trans, "reuse input buffer");
+      } else {
+        /* Writable buffer, but need to change caps => subbuffer */
+        *out_buf = gst_buffer_create_sub (in_buf, 0, GST_BUFFER_SIZE (in_buf));
+        gst_caps_replace (&GST_BUFFER_CAPS (*out_buf), out_caps);
+        GST_LOG_OBJECT (trans, "created sub-buffer of input buffer");
+      }
+      /* we are done now */
+      goto done;
+    } else {
+      /* Make a writable buffer below and copy the data */
+      copy_inbuf = TRUE;
+      GST_LOG_OBJECT (trans, "need to copy input buffer to new output buffer");
+    }
+  }
+
+  if (*out_buf == NULL) {
+    /* Sub-class didn't already provide a buffer for us. Make one */
+    ret = gst_pad_alloc_buffer (trans->srcpad,
+        GST_BUFFER_OFFSET (in_buf), out_size, out_caps, out_buf);
+    if (ret != GST_FLOW_OK || *out_buf == NULL)
+      goto done;
+
+    /* allocated buffer could be of different caps than what we requested */
+    if (G_UNLIKELY (!gst_caps_is_equal (out_caps, GST_BUFFER_CAPS (*out_buf)))) {
+      /* FIXME, it is possible we can reconfigure the transform with new caps at this
+       * point but for now we just create a buffer ourselves */
+      gst_buffer_unref (*out_buf);
+      *out_buf = gst_buffer_new_and_alloc (out_size);
+      gst_buffer_set_caps (*out_buf, out_caps);
+    }
+  }
+
+  /* If the output buffer metadata is modifiable, copy timestamps and
+   * buffer flags */
+  if (*out_buf != in_buf && gst_buffer_is_metadata_writable (*out_buf)) {
+
+    if (copy_inbuf && gst_buffer_is_writable (*out_buf))
+      memcpy (GST_BUFFER_DATA (*out_buf), GST_BUFFER_DATA (in_buf), out_size);
+
+    gst_buffer_copy_metadata (*out_buf, in_buf,
+        GST_BUFFER_COPY_FLAGS | GST_BUFFER_COPY_TIMESTAMPS);
+
+    /* Unset the GAP flag if the element is _not_ GAP aware. Otherwise
+     * it might create an output buffer that does not contain neutral data
+     * but still has the GAP flag on it! */
+    if (!trans->priv->gap_aware)
+      GST_BUFFER_FLAG_UNSET (*out_buf, GST_BUFFER_FLAG_GAP);
+  }
+
+done:
+  if (out_caps)
+    gst_caps_unref (out_caps);
+
+  trans->delay_configure = FALSE;
+
+  return ret;
+}
+
+/* Given @caps calcultate the size of one unit.
+ *
+ * For video caps, this is the size of one frame (and thus one buffer).
+ * For audio caps, this is the size of one sample.
+ *
+ * These values are cached since they do not change and the calculation
+ * potentially involves parsing caps and other expensive stuff.
+ *
+ * We have two cache locations to store the size, one for the source caps
+ * and one for the sink caps.
+ *
+ * this function returns FALSE if no size could be calculated.
+ */
+static gboolean
+gst_base_transform_get_unit_size (GstBaseTransform * trans, GstCaps * caps,
+    guint * size)
+{
+  gboolean res = FALSE;
+  GstBaseTransformClass *bclass;
+
+  /* see if we have the result cached */
+  if (trans->cache_caps1 == caps) {
+    *size = trans->cache_caps1_size;
+    GST_DEBUG_OBJECT (trans, "returned %d from first cache", *size);
+    return TRUE;
+  }
+  if (trans->cache_caps2 == caps) {
+    *size = trans->cache_caps2_size;
+    GST_DEBUG_OBJECT (trans, "returned %d from second cached", *size);
+    return TRUE;
+  }
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+  if (bclass->get_unit_size) {
+    res = bclass->get_unit_size (trans, caps, size);
+//    GST_DEBUG_OBJECT (trans, "caps %" GST_PTR_FORMAT
+//        ") has unit size %d, result %s", caps, *size, res ? "TRUE" : "FALSE");
+
+    if (res) {
+      /* and cache the values */
+      if (trans->cache_caps1 == NULL) {
+        gst_caps_replace (&trans->cache_caps1, caps);
+        trans->cache_caps1_size = *size;
+        GST_DEBUG_OBJECT (trans, "caching %d in first cache", *size);
+      } else if (trans->cache_caps2 == NULL) {
+        gst_caps_replace (&trans->cache_caps2, caps);
+        trans->cache_caps2_size = *size;
+        GST_DEBUG_OBJECT (trans, "caching %d in second cache", *size);
+      } else {
+        GST_DEBUG_OBJECT (trans, "no free spot to cache unit_size");
+      }
+    }
+  } else {
+    GST_DEBUG_OBJECT (trans, "Sub-class does not implement get_unit_size");
+  }
+  return res;
+}
+
+/* your upstream peer wants to send you a buffer
+ * that buffer has the given offset, size and caps
+ * you're requested to allocate a buffer
+ */
+static GstFlowReturn
+gst_base_transform_buffer_alloc (GstPad * pad, guint64 offset, guint size,
+    GstCaps * caps, GstBuffer ** buf)
+{
+  GstBaseTransform *trans;
+  GstFlowReturn res;
+  guint new_size;
+  gboolean issinkcaps = TRUE;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  /* we cannot run this when we are transforming data and as such doing 
+   * another negotiation in the transform method. */
+  g_mutex_lock (trans->transform_lock);
+
+  *buf = NULL;
+
+  GST_DEBUG_OBJECT (trans, "allocating a buffer of size %d ...", size);
+  if (offset == GST_BUFFER_OFFSET_NONE)
+    GST_DEBUG_OBJECT (trans, "... and offset NONE");
+  else
+    GST_DEBUG_OBJECT (trans, "... and offset %" G_GUINT64_FORMAT, offset);
+
+  /* if have_same_caps was previously set to TRUE we need to double check if it
+   * hasn't changed */
+  if (trans->have_same_caps) {
+    GstCaps *sinkcaps;
+
+    GST_OBJECT_LOCK (trans->sinkpad);
+    sinkcaps = GST_PAD_CAPS (trans->sinkpad);
+    issinkcaps = sinkcaps && (gst_caps_is_equal (sinkcaps, caps));
+    GST_OBJECT_UNLOCK (trans->sinkpad);
+  }
+
+  /* before any buffers are pushed, have_same_caps is TRUE; allocating can trigger
+   * a renegotiation and change that to FALSE */
+
+  /* bilboed: This seems wrong, from all debug logs, have_same_caps is
+   * initialized to FALSE */
+
+  /* checking against trans->have_same_caps is not enough !! It should also
+   *  check to see if the requested caps are equal to the sink caps */
+  if (trans->have_same_caps && issinkcaps) {
+    /* request a buffer with the same caps */
+    GST_DEBUG_OBJECT (trans, "requesting buffer with same caps, size %d", size);
+
+    res =
+        gst_pad_alloc_buffer_and_set_caps (trans->srcpad, offset, size, caps,
+        buf);
+  } else {
+    /* if we are configured, request a buffer with the src caps */
+    GstCaps *srccaps;
+    GstCaps *sinkcaps;
+    gboolean configured;
+
+    /* take lock, peek if the caps are ok */
+    GST_OBJECT_LOCK (trans->sinkpad);
+    sinkcaps = GST_PAD_CAPS (trans->sinkpad);
+    configured = (sinkcaps == NULL || gst_caps_is_equal (sinkcaps, caps));
+    GST_OBJECT_UNLOCK (trans->sinkpad);
+    if (!configured)
+      goto not_configured;
+
+    /* take lock on srcpad to grab the caps, caps can change when pushing a
+     * buffer. */
+    GST_OBJECT_LOCK (trans->srcpad);
+    if ((srccaps = GST_PAD_CAPS (trans->srcpad)))
+      gst_caps_ref (srccaps);
+    GST_OBJECT_UNLOCK (trans->srcpad);
+    if (!srccaps)
+      goto not_configured;
+
+    GST_DEBUG_OBJECT (trans, "calling transform_size");
+    if (!gst_base_transform_transform_size (trans,
+            GST_PAD_DIRECTION (pad), caps, size, srccaps, &new_size)) {
+      gst_caps_unref (srccaps);
+      goto unknown_size;
+    }
+
+    res =
+        gst_pad_alloc_buffer_and_set_caps (trans->srcpad, offset, new_size,
+        srccaps, buf);
+
+    gst_caps_unref (srccaps);
+  }
+
+  if (res == GST_FLOW_OK && !trans->have_same_caps) {
+    /* note that we might have had same caps before, but calling the
+       alloc_buffer caused setcaps to switch us out of in_place -- in any case
+       the alloc_buffer served to transmit caps information but we can't use the
+       buffer. fall through and allocate a buffer corresponding to our sink
+       caps, if any */
+    GstCaps *sinkcaps;
+    GstCaps *srccaps;
+
+    GST_OBJECT_LOCK (trans->sinkpad);
+    if ((sinkcaps = GST_PAD_CAPS (trans->sinkpad)))
+      gst_caps_ref (sinkcaps);
+    GST_OBJECT_UNLOCK (trans->sinkpad);
+    if (!sinkcaps)
+      goto not_configured;
+
+    GST_OBJECT_LOCK (trans->srcpad);
+    if ((srccaps = GST_PAD_CAPS (trans->srcpad)))
+      gst_caps_ref (srccaps);
+    GST_OBJECT_UNLOCK (trans->srcpad);
+    if (!srccaps) {
+      gst_caps_unref (sinkcaps);
+      goto not_configured;
+    }
+
+    if (!gst_base_transform_transform_size (trans,
+            GST_PAD_DIRECTION (trans->srcpad), srccaps, GST_BUFFER_SIZE (*buf),
+            sinkcaps, &new_size)) {
+      gst_caps_unref (srccaps);
+      gst_caps_unref (sinkcaps);
+      goto unknown_size;
+    }
+    /* don't need the caps anymore now */
+    gst_caps_unref (srccaps);
+
+    gst_buffer_unref (*buf);
+
+    *buf = gst_buffer_new_and_alloc (new_size);
+    GST_BUFFER_OFFSET (*buf) = offset;
+    /* set caps, gives away the ref */
+    GST_BUFFER_CAPS (*buf) = sinkcaps;
+
+    res = GST_FLOW_OK;
+  }
+
+done:
+  g_mutex_unlock (trans->transform_lock);
+  gst_object_unref (trans);
+
+  return res;
+
+not_configured:
+  {
+    /* let the default allocator handle it... */
+    GST_DEBUG_OBJECT (trans, "not configured");
+    gst_buffer_replace (buf, NULL);
+    if (trans->passthrough) {
+      /* ...by calling alloc_buffer without setting caps on the src pad, which
+       * will force negotiation in the chain function. */
+      res = gst_pad_alloc_buffer (trans->srcpad, offset, size, caps, buf);
+    } else {
+      /* ...by letting the default handler create a buffer */
+      res = GST_FLOW_OK;
+    }
+    goto done;
+  }
+unknown_size:
+  {
+    /* let the default allocator handle it... */
+    GST_DEBUG_OBJECT (trans, "unknown size");
+    gst_buffer_replace (buf, NULL);
+    if (trans->passthrough) {
+      /* ...by calling alloc_buffer without setting caps on the src pad, which
+       * will force negotiation in the chain function. */
+      res = gst_pad_alloc_buffer (trans->srcpad, offset, size, caps, buf);
+    } else {
+      /* ...by letting the default handler create a buffer */
+      res = GST_FLOW_OK;
+    }
+    goto done;
+  }
+}
+
+static gboolean
+gst_base_transform_sink_event (GstPad * pad, GstEvent * event)
+{
+  GstBaseTransform *trans;
+  GstBaseTransformClass *bclass;
+  gboolean ret = TRUE;
+  gboolean forward = TRUE;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  if (bclass->event)
+    forward = bclass->event (trans, event);
+
+  /* FIXME, do this in the default event handler so the subclass can do
+   * something different. */
+  if (forward)
+    ret = gst_pad_push_event (trans->srcpad, event);
+
+  gst_object_unref (trans);
+
+  return ret;
+}
+
+static gboolean
+gst_base_transform_sink_eventfunc (GstBaseTransform * trans, GstEvent * event)
+{
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_FLUSH_START:
+      break;
+    case GST_EVENT_FLUSH_STOP:
+      GST_OBJECT_LOCK (trans);
+      /* reset QoS parameters */
+      trans->priv->proportion = 1.0;
+      trans->priv->earliest_time = -1;
+      trans->priv->discont = FALSE;
+      GST_OBJECT_UNLOCK (trans);
+      /* we need new segment info after the flush. */
+      trans->have_newsegment = FALSE;
+      gst_segment_init (&trans->segment, GST_FORMAT_UNDEFINED);
+      break;
+    case GST_EVENT_EOS:
+      break;
+    case GST_EVENT_TAG:
+      break;
+    case GST_EVENT_NEWSEGMENT:
+    {
+      GstFormat format;
+      gdouble rate, arate;
+      gint64 start, stop, time;
+      gboolean update;
+
+      gst_event_parse_new_segment_full (event, &update, &rate, &arate, &format,
+          &start, &stop, &time);
+
+      trans->have_newsegment = TRUE;
+
+      gst_segment_set_newsegment_full (&trans->segment, update, rate, arate,
+          format, start, stop, time);
+
+      if (format == GST_FORMAT_TIME) {
+        GST_DEBUG_OBJECT (trans, "received TIME NEW_SEGMENT %" GST_TIME_FORMAT
+            " -- %" GST_TIME_FORMAT ", time %" GST_TIME_FORMAT
+            ", accum %" GST_TIME_FORMAT,
+            GST_TIME_ARGS (trans->segment.start),
+            GST_TIME_ARGS (trans->segment.stop),
+            GST_TIME_ARGS (trans->segment.time),
+            GST_TIME_ARGS (trans->segment.accum));
+      } else {
+        GST_DEBUG_OBJECT (trans, "received NEW_SEGMENT %" G_GINT64_FORMAT
+            " -- %" G_GINT64_FORMAT ", time %" G_GINT64_FORMAT
+            ", accum %" G_GINT64_FORMAT,
+            trans->segment.start, trans->segment.stop,
+            trans->segment.time, trans->segment.accum);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_base_transform_src_event (GstPad * pad, GstEvent * event)
+{
+  GstBaseTransform *trans;
+  GstBaseTransformClass *bclass;
+  gboolean ret = TRUE;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  if (bclass->src_event)
+    ret = bclass->src_event (trans, event);
+
+  gst_object_unref (trans);
+
+  return ret;
+}
+
+static gboolean
+gst_base_transform_src_eventfunc (GstBaseTransform * trans, GstEvent * event)
+{
+  gboolean ret;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:
+      break;
+    case GST_EVENT_NAVIGATION:
+      break;
+    case GST_EVENT_QOS:
+    {
+      gdouble proportion;
+      GstClockTimeDiff diff;
+      GstClockTime timestamp;
+
+      gst_event_parse_qos (event, &proportion, &diff, &timestamp);
+      gst_base_transform_update_qos (trans, proportion, diff, timestamp);
+      break;
+    }
+    default:
+      break;
+  }
+
+  ret = gst_pad_push_event (trans->sinkpad, event);
+
+  return ret;
+}
+
+static GstFlowReturn
+gst_base_transform_handle_buffer (GstBaseTransform * trans, GstBuffer * inbuf,
+    GstBuffer ** outbuf)
+{
+  GstBaseTransformClass *bclass;
+  GstFlowReturn ret = GST_FLOW_OK;
+  guint out_size;
+  gboolean want_in_place;
+  GstClockTime qostime;
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  if (GST_BUFFER_OFFSET_IS_VALID (inbuf))
+    GST_LOG_OBJECT (trans, "handling buffer %p of size %d and offset %"
+        G_GUINT64_FORMAT, inbuf, GST_BUFFER_SIZE (inbuf),
+        GST_BUFFER_OFFSET (inbuf));
+  else
+    GST_LOG_OBJECT (trans, "handling buffer %p of size %d and offset NONE",
+        inbuf, GST_BUFFER_SIZE (inbuf));
+
+  /* Don't allow buffer handling before negotiation, except in passthrough mode
+   * or if the class doesn't implement a set_caps function (in which case it doesn't
+   * care about caps)
+   */
+  if (!trans->negotiated && !trans->passthrough && (bclass->set_caps != NULL))
+    goto not_negotiated;
+
+  /* Set discont flag so we can mark the outgoing buffer */
+  if (GST_BUFFER_IS_DISCONT (inbuf)) {
+    GST_LOG_OBJECT (trans, "got DISCONT buffer %p", inbuf);
+    trans->priv->discont = TRUE;
+  }
+
+  /* can only do QoS if the segment is in TIME */
+  if (trans->segment.format != GST_FORMAT_TIME)
+    goto no_qos;
+
+  qostime = gst_segment_to_running_time (&trans->segment, GST_FORMAT_TIME,
+      GST_BUFFER_TIMESTAMP (inbuf));
+
+  if (qostime != -1) {
+    gboolean need_skip;
+    GstClockTime earliest_time;
+
+    GST_OBJECT_LOCK (trans);
+    earliest_time = trans->priv->earliest_time;
+    /* check for QoS, don't perform conversion for buffers
+     * that are known to be late. */
+    need_skip = trans->priv->qos_enabled &&
+        earliest_time != -1 && qostime != -1 && qostime <= earliest_time;
+    GST_OBJECT_UNLOCK (trans);
+
+    if (need_skip) {
+      GST_CAT_DEBUG_OBJECT (GST_CAT_QOS, trans, "skipping transform: qostime %"
+          GST_TIME_FORMAT " <= %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (qostime), GST_TIME_ARGS (earliest_time));
+      /* mark discont for next buffer */
+      trans->priv->discont = TRUE;
+      goto skip;
+    }
+  }
+
+no_qos:
+  if (trans->passthrough) {
+    /* In passthrough mode, give transform_ip a look at the
+     * buffer, without making it writable, or just push the
+     * data through */
+    GST_LOG_OBJECT (trans, "element is in passthrough mode");
+
+    if (bclass->transform_ip)
+      ret = bclass->transform_ip (trans, inbuf);
+
+    *outbuf = inbuf;
+
+    goto done;
+  }
+
+  want_in_place = (bclass->transform_ip != NULL) && trans->always_in_place;
+  *outbuf = NULL;
+
+  if (want_in_place) {
+    /* If want_in_place is TRUE, we may need to prepare a new output buffer
+     * Sub-classes can implement a prepare_output_buffer function as they
+     * wish. */
+    GST_LOG_OBJECT (trans, "doing inplace transform");
+
+    ret = gst_base_transform_prepare_output_buffer (trans, inbuf,
+        GST_BUFFER_SIZE (inbuf), GST_PAD_CAPS (trans->srcpad), outbuf);
+    if (G_UNLIKELY (ret != GST_FLOW_OK))
+      goto no_buffer;
+
+    ret = bclass->transform_ip (trans, *outbuf);
+
+  } else {
+    GST_LOG_OBJECT (trans, "doing non-inplace transform");
+
+    /* not transforming inplace, figure out the output size */
+    if (trans->always_in_place) {
+      out_size = GST_BUFFER_SIZE (inbuf);
+    } else {
+      if (!gst_base_transform_transform_size (trans,
+              GST_PAD_DIRECTION (trans->sinkpad), GST_PAD_CAPS (trans->sinkpad),
+              GST_BUFFER_SIZE (inbuf), GST_PAD_CAPS (trans->srcpad),
+              &out_size)) {
+        /* we have an error */
+        goto no_size;
+      }
+    }
+
+    /* no in place transform, get buffer, this might renegotiate. */
+    ret = gst_base_transform_prepare_output_buffer (trans, inbuf, out_size,
+        GST_PAD_CAPS (trans->srcpad), outbuf);
+    if (ret != GST_FLOW_OK)
+      goto no_buffer;
+
+    if (bclass->transform)
+      ret = bclass->transform (trans, inbuf, *outbuf);
+    else
+      ret = GST_FLOW_NOT_SUPPORTED;
+  }
+
+  /* if we got renegotiated we can configure now */
+  if (trans->pending_configure) {
+    gboolean success;
+
+    success =
+        gst_base_transform_configure_caps (trans,
+        GST_PAD_CAPS (trans->sinkpad), GST_PAD_CAPS (trans->srcpad));
+
+    trans->pending_configure = FALSE;
+
+    if (!success)
+      goto configure_failed;
+  }
+
+skip:
+  /* only unref input buffer if we allocated a new outbuf buffer */
+  if (*outbuf != inbuf)
+    gst_buffer_unref (inbuf);
+
+done:
+  return ret;
+
+  /* ERRORS */
+not_negotiated:
+  {
+    gst_buffer_unref (inbuf);
+    GST_ELEMENT_ERROR (trans, STREAM, NOT_IMPLEMENTED,
+        ("not negotiated"), ("not negotiated"));
+    return GST_FLOW_NOT_NEGOTIATED;
+  }
+no_size:
+  {
+    gst_buffer_unref (inbuf);
+    GST_ELEMENT_ERROR (trans, STREAM, NOT_IMPLEMENTED,
+        ("subclass did not specify output size"),
+        ("subclass did not specify output size"));
+    return GST_FLOW_ERROR;
+  }
+no_buffer:
+  {
+    gst_buffer_unref (inbuf);
+    GST_DEBUG_OBJECT (trans, "could not get buffer from pool: %s",
+        gst_flow_get_name (ret));
+    return ret;
+  }
+configure_failed:
+  {
+    if (*outbuf != inbuf)
+      gst_buffer_unref (inbuf);
+    GST_DEBUG_OBJECT (trans, "could not negotiate");
+    return GST_FLOW_NOT_NEGOTIATED;
+  }
+}
+
+static gboolean
+gst_base_transform_check_get_range (GstPad * pad)
+{
+  GstBaseTransform *trans;
+  gboolean ret;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  ret = gst_pad_check_pull_range (trans->sinkpad);
+
+  gst_object_unref (trans);
+
+  return ret;
+}
+
+/* FIXME, getrange is broken, need to pull range from the other
+ * end based on the transform_size result.
+ */
+static GstFlowReturn
+gst_base_transform_getrange (GstPad * pad, guint64 offset,
+    guint length, GstBuffer ** buffer)
+{
+  GstBaseTransform *trans;
+  GstFlowReturn ret;
+  GstBuffer *inbuf;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  ret = gst_pad_pull_range (trans->sinkpad, offset, length, &inbuf);
+  if (ret == GST_FLOW_OK) {
+    g_mutex_lock (trans->transform_lock);
+    ret = gst_base_transform_handle_buffer (trans, inbuf, buffer);
+    g_mutex_unlock (trans->transform_lock);
+  }
+
+  gst_object_unref (trans);
+
+  return ret;
+}
+
+static GstFlowReturn
+gst_base_transform_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstBaseTransform *trans;
+  GstFlowReturn ret;
+  GstClockTime last_stop = GST_CLOCK_TIME_NONE;
+  GstBuffer *outbuf = NULL;
+
+  trans = GST_BASE_TRANSFORM (GST_OBJECT_PARENT (pad));
+
+  /* calculate end position of the incoming buffer */
+  if (GST_BUFFER_TIMESTAMP (buffer) != GST_CLOCK_TIME_NONE) {
+    if (GST_BUFFER_DURATION (buffer) != GST_CLOCK_TIME_NONE)
+      last_stop = GST_BUFFER_TIMESTAMP (buffer) + GST_BUFFER_DURATION (buffer);
+    else
+      last_stop = GST_BUFFER_TIMESTAMP (buffer);
+  }
+
+  /* protect transform method and concurrent buffer alloc */
+  g_mutex_lock (trans->transform_lock);
+  ret = gst_base_transform_handle_buffer (trans, buffer, &outbuf);
+  g_mutex_unlock (trans->transform_lock);
+
+  /* outbuf can be NULL, this means a dropped buffer, if we have a buffer but
+   * GST_BASE_TRANSFORM_FLOW_DROPPED we will not push either. */
+  if (outbuf != NULL) {
+    if ((ret == GST_FLOW_OK)) {
+      /* Remember last stop position */
+      if ((last_stop != GST_CLOCK_TIME_NONE) &&
+          (trans->segment.format == GST_FORMAT_TIME))
+        gst_segment_set_last_stop (&trans->segment, GST_FORMAT_TIME, last_stop);
+
+      /* apply DISCONT flag if the buffer is not yet marked as such */
+      if (trans->priv->discont) {
+        if (!GST_BUFFER_IS_DISCONT (outbuf)) {
+          outbuf = gst_buffer_make_metadata_writable (outbuf);
+          GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DISCONT);
+        }
+        trans->priv->discont = FALSE;
+      }
+      ret = gst_pad_push (trans->srcpad, outbuf);
+    } else
+      gst_buffer_unref (outbuf);
+  }
+
+  /* convert internal flow to OK and mark discont for the next buffer. */
+  if (ret == GST_BASE_TRANSFORM_FLOW_DROPPED) {
+    trans->priv->discont = TRUE;
+    ret = GST_FLOW_OK;
+  }
+
+  return ret;
+}
+
+static void
+gst_base_transform_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstBaseTransform *trans;
+
+  trans = GST_BASE_TRANSFORM (object);
+
+  switch (prop_id) {
+    case PROP_QOS:
+      gst_base_transform_set_qos_enabled (trans, g_value_get_boolean (value));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_base_transform_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstBaseTransform *trans;
+
+  trans = GST_BASE_TRANSFORM (object);
+
+  switch (prop_id) {
+    case PROP_QOS:
+      g_value_set_boolean (value, gst_base_transform_is_qos_enabled (trans));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/* not a vmethod of anything, just an internal method */
+static gboolean
+gst_base_transform_activate (GstBaseTransform * trans, gboolean active)
+{
+  GstBaseTransformClass *bclass;
+  gboolean result = TRUE;
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  if (active) {
+    if (trans->priv->pad_mode == GST_ACTIVATE_NONE && bclass->start)
+      result &= bclass->start (trans);
+
+    GST_OBJECT_LOCK (trans);
+
+    if (GST_PAD_CAPS (trans->sinkpad) && GST_PAD_CAPS (trans->srcpad))
+      trans->have_same_caps =
+          gst_caps_is_equal (GST_PAD_CAPS (trans->sinkpad),
+          GST_PAD_CAPS (trans->srcpad)) || trans->passthrough;
+    else
+      trans->have_same_caps = trans->passthrough;
+    GST_DEBUG_OBJECT (trans, "have_same_caps %d", trans->have_same_caps);
+    trans->negotiated = FALSE;
+    trans->have_newsegment = FALSE;
+    gst_segment_init (&trans->segment, GST_FORMAT_UNDEFINED);
+    trans->priv->proportion = 1.0;
+    trans->priv->earliest_time = -1;
+    trans->priv->discont = FALSE;
+
+    GST_OBJECT_UNLOCK (trans);
+  } else {
+    /* We must make sure streaming has finished before resetting things
+     * and calling the ::stop vfunc */
+    GST_PAD_STREAM_LOCK (trans->sinkpad);
+    GST_PAD_STREAM_UNLOCK (trans->sinkpad);
+
+    trans->have_same_caps = FALSE;
+    /* We can only reset the passthrough mode if the instance told us to 
+       handle it in configure_caps */
+    if (bclass->passthrough_on_same_caps) {
+      gst_base_transform_set_passthrough (trans, FALSE);
+    }
+    gst_caps_replace (&trans->cache_caps1, NULL);
+    gst_caps_replace (&trans->cache_caps2, NULL);
+
+    if (trans->priv->pad_mode != GST_ACTIVATE_NONE && bclass->stop)
+      result &= bclass->stop (trans);
+  }
+
+  return result;
+}
+
+static gboolean
+gst_base_transform_sink_activate_push (GstPad * pad, gboolean active)
+{
+  gboolean result = TRUE;
+  GstBaseTransform *trans;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  result = gst_base_transform_activate (trans, active);
+
+  if (result)
+    trans->priv->pad_mode = active ? GST_ACTIVATE_PUSH : GST_ACTIVATE_NONE;
+
+  gst_object_unref (trans);
+
+  return result;
+}
+
+static gboolean
+gst_base_transform_src_activate_pull (GstPad * pad, gboolean active)
+{
+  gboolean result = FALSE;
+  GstBaseTransform *trans;
+
+  trans = GST_BASE_TRANSFORM (gst_pad_get_parent (pad));
+
+  result = gst_pad_activate_pull (trans->sinkpad, active);
+
+  if (result)
+    result &= gst_base_transform_activate (trans, active);
+
+  if (result)
+    trans->priv->pad_mode = active ? GST_ACTIVATE_PULL : GST_ACTIVATE_NONE;
+
+  gst_object_unref (trans);
+
+  return result;
+}
+
+/**
+ * gst_base_transform_set_passthrough:
+ * @trans: the #GstBaseTransform to set
+ * @passthrough: boolean indicating passthrough mode.
+ *
+ * Set passthrough mode for this filter by default. This is mostly
+ * useful for filters that do not care about negotiation.
+ *
+ * Always TRUE for filters which don't implement either a transform
+ * or transform_ip method.
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_base_transform_set_passthrough (GstBaseTransform * trans,
+    gboolean passthrough)
+{
+  GstBaseTransformClass *bclass;
+
+  g_return_if_fail (trans != NULL);
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  GST_OBJECT_LOCK (trans);
+  if (passthrough == FALSE) {
+    if (bclass->transform_ip || bclass->transform)
+      trans->passthrough = FALSE;
+  } else {
+    trans->passthrough = TRUE;
+  }
+
+  GST_DEBUG_OBJECT (trans, "set passthrough %d", trans->passthrough);
+  GST_OBJECT_UNLOCK (trans);
+}
+
+/**
+ * gst_base_transform_is_passthrough:
+ * @trans: the #GstBaseTransform to query
+ *
+ * See if @trans is configured as a passthrough transform.
+ *
+ * Returns: TRUE is the transform is configured in passthrough mode.
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_base_transform_is_passthrough (GstBaseTransform * trans)
+{
+  gboolean result;
+
+  g_return_val_if_fail (trans != NULL, FALSE);
+
+  GST_OBJECT_LOCK (trans);
+  result = trans->passthrough;
+  GST_OBJECT_UNLOCK (trans);
+
+  return result;
+}
+
+/**
+ * gst_base_transform_set_in_place:
+ * @trans: the #GstBaseTransform to modify
+ * @in_place: Boolean value indicating that we would like to operate
+ * on in_place buffers.
+ *
+ * Determines whether a non-writable buffer will be copied before passing
+ * to the transform_ip function.
+ * <itemizedlist>
+ *   <listitem>Always TRUE if no transform function is implemented.</listitem>
+ *   <listitem>Always FALSE if ONLY transform_ip function is implemented.</listitem>
+ * </itemizedlist>
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_base_transform_set_in_place (GstBaseTransform * trans, gboolean in_place)
+{
+  GstBaseTransformClass *bclass;
+
+  g_return_if_fail (trans != NULL);
+
+  bclass = GST_BASE_TRANSFORM_GET_CLASS (trans);
+
+  GST_OBJECT_LOCK (trans);
+
+  if (in_place) {
+    if (bclass->transform_ip) {
+      GST_DEBUG_OBJECT (trans, "setting in_place TRUE");
+      trans->always_in_place = TRUE;
+    }
+  } else {
+    if (bclass->transform) {
+      GST_DEBUG_OBJECT (trans, "setting in_place FALSE");
+      trans->always_in_place = FALSE;
+    }
+  }
+
+  GST_OBJECT_UNLOCK (trans);
+}
+
+/**
+ * gst_base_transform_is_in_place:
+ * @trans: the #GstBaseTransform to query
+ *
+ * See if @trans is configured as a in_place transform.
+ *
+ * Returns: TRUE is the transform is configured in in_place mode.
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_base_transform_is_in_place (GstBaseTransform * trans)
+{
+  gboolean result;
+
+  g_return_val_if_fail (trans != NULL, FALSE);
+
+  GST_OBJECT_LOCK (trans);
+  result = trans->always_in_place;
+  GST_OBJECT_UNLOCK (trans);
+
+  return result;
+}
+
+/**
+ * gst_base_transform_update_qos:
+ * @trans: a #GstBaseTransform
+ * @proportion: the proportion
+ * @diff: the diff against the clock
+ * @timestamp: the timestamp of the buffer generating the QoS
+ *
+ * Set the QoS parameters in the transform.
+ *
+ * Since: 0.10.5
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_base_transform_update_qos (GstBaseTransform * trans,
+    gdouble proportion, GstClockTimeDiff diff, GstClockTime timestamp)
+{
+
+  g_return_if_fail (trans != NULL);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_QOS, trans,
+      "qos: proportion: %lf, diff %" G_GINT64_FORMAT ", timestamp %"
+      GST_TIME_FORMAT, proportion, diff, GST_TIME_ARGS (timestamp));
+
+  GST_OBJECT_LOCK (trans);
+  trans->priv->proportion = proportion;
+  trans->priv->earliest_time = timestamp + diff;
+  GST_OBJECT_UNLOCK (trans);
+}
+
+/**
+ * gst_base_transform_set_qos_enabled:
+ * @trans: a #GstBaseTransform
+ * @enabled: new state
+ *
+ * Enable or disable QoS handling in the transform.
+ *
+ * Since: 0.10.5
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_base_transform_set_qos_enabled (GstBaseTransform * trans, gboolean enabled)
+{
+  g_return_if_fail (trans != NULL);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_QOS, trans, "enabled: %d", enabled);
+
+  GST_OBJECT_LOCK (trans);
+  trans->priv->qos_enabled = enabled;
+  GST_OBJECT_UNLOCK (trans);
+}
+
+/**
+ * gst_base_transform_is_qos_enabled:
+ * @trans: a #GstBaseTransform
+ *
+ * Queries if the transform will handle QoS.
+ *
+ * Returns: TRUE if QoS is enabled.
+ *
+ * Since: 0.10.5
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_base_transform_is_qos_enabled (GstBaseTransform * trans)
+{
+  gboolean result;
+
+  g_return_val_if_fail (trans != NULL, FALSE);
+
+  GST_OBJECT_LOCK (trans);
+  result = trans->priv->qos_enabled;
+  GST_OBJECT_UNLOCK (trans);
+
+  return result;
+}
+
+/**
+ * gst_base_transform_set_gap_aware:
+ * @trans: a #GstBaseTransform
+ * @gap_aware: New state
+ *
+ * If @gap_aware is %FALSE (as it is by default) subclasses will never get
+ * output buffers with the %GST_BUFFER_FLAG_GAP flag set.
+ *
+ * If set to %TRUE elements must handle output buffers with this flag set
+ * correctly, i.e. they can assume that the buffer contains neutral data
+ * but must unset the flag if the output is no neutral data.
+ * Since: 0.10.16
+ *
+ * MT safe.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_base_transform_set_gap_aware (GstBaseTransform * trans, gboolean gap_aware)
+{
+  g_return_if_fail (trans != NULL);
+
+  GST_OBJECT_LOCK (trans);
+  trans->priv->gap_aware = gap_aware;
+  GST_DEBUG_OBJECT (trans, "set gap aware %d", trans->priv->gap_aware);
+  GST_OBJECT_UNLOCK (trans);
+}