Add new libsoundtouch-based pitch plugin (#331335).

Original commit message from CVS:
Patch by: Wouter Paeson  <wouter at kangaroot dot net>
* configure.ac:
* ext/Makefile.am:
* ext/soundtouch/Makefile.am:
* ext/soundtouch/gstpitch.cc:
* ext/soundtouch/gstpitch.hh:
Add new libsoundtouch-based pitch plugin (#331335).

3 files changed, 806 insertions, 0 deletions

diff --git a/ext/soundtouch/Makefile.am b/ext/soundtouch/Makefile.am
new file mode 100644
index 000000000..d286bfce6
--- /dev/null
+++ b/ext/soundtouch/Makefile.am
@@ -0,0 +1,9 @@
+plugin_LTLIBRARIES = libgstpitch.la
+
+libgstpitch_la_SOURCES = gstpitch.cc
+
+libgstpitch_la_CXXFLAGS = @GST_CFLAGS@ @GST_BASE_CFLAGS@ @SOUNDTOUCH_CFLAGS@
+libgstpitch_la_LIBADD = @GST_LIBS@ @GST_BASE_LIBS@ @SOUNDTOUCH_LIBS@
+libgstpitch_la_LDFLAGS = @GST_PLUGIN_LDFLAGS@
+
+noinst_HEADERS = gstpitch.hh
diff --git a/ext/soundtouch/gstpitch.cc b/ext/soundtouch/gstpitch.cc
new file mode 100644
index 000000000..a0ad874d4
--- /dev/null
+++ b/ext/soundtouch/gstpitch.cc
@@ -0,0 +1,709 @@
+/* GStreamer pitch controller element
+ * Copyright (C) 2006 Wouter Paesen <wouter@blue-gate.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <gst/gst.h>
+#include "gstpitch.hh"
+#include <math.h>
+
+#define FLOAT_SAMPLES
+#include <soundtouch/SoundTouch.h>
+
+/* wtf ?
+#ifdef G_PARAM_READWRITE
+#  undef G_PARAM_READWRITE
+#endif
+#define G_PARAM_READWRITE ((GParamFlags)(G_PARAM_READABLE | G_PARAM_WRITABLE))
+*/
+
+GST_DEBUG_CATEGORY_STATIC (pitch_debug);
+#define GST_CAT_DEFAULT pitch_debug
+
+#define GST_PITCH_GET_PRIVATE(o) (o->priv)
+struct _GstPitchPrivate
+{
+  gfloat stream_time_ratio;
+
+    soundtouch::SoundTouch * st;
+};
+
+static GstElementDetails gst_pitch_details =
+GST_ELEMENT_DETAILS ("Pitch controller",
+    "Filter/Converter/Audio",
+    "Control the pitch of an audio stream",
+    "Wouter Paesen <wouter@kangaroot.net>");
+
+enum
+{
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0,
+  ARG_RATE,
+  ARG_TEMPO,
+  ARG_PITCH,
+};
+
+#define SUPPORTED_CAPS \
+GST_STATIC_CAPS( \
+  "audio/x-raw-float, " \
+    "rate = (int) [ 8000, 48000 ], " \
+    "channels = (int) [ 1, 2 ], " \
+    "endianness = (int) BYTE_ORDER, " \
+    "width = (int) 32, " \
+    "buffer-frames = (int) [ 0, MAX ]" \
+)
+
+static GstStaticPadTemplate gst_pitch_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    SUPPORTED_CAPS);
+
+static GstStaticPadTemplate gst_pitch_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    SUPPORTED_CAPS);
+
+static void gst_pitch_dispose (GObject * object);
+static void gst_pitch_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec);
+static void gst_pitch_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec);
+
+
+static gboolean gst_pitch_sink_setcaps (GstPad * pad, GstCaps * caps);
+static GstFlowReturn gst_pitch_chain (GstPad * pad, GstBuffer * buffer);
+static GstStateChangeReturn gst_pitch_change_state (GstElement * element,
+    GstStateChange transition);
+static gboolean gst_pitch_sink_event (GstPad * pad, GstEvent * event);
+static gboolean gst_pitch_src_event (GstPad * pad, GstEvent * event);
+
+static gboolean gst_pitch_src_query (GstPad * pad, GstQuery * query);
+static const GstQueryType *gst_pitch_get_query_types (GstPad * pad);
+
+GST_BOILERPLATE (GstPitch, gst_pitch, GstElement, GST_TYPE_ELEMENT);
+
+static void
+gst_pitch_base_init (gpointer g_class)
+{
+  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&gst_pitch_src_template));
+  gst_element_class_add_pad_template (gstelement_class,
+      gst_static_pad_template_get (&gst_pitch_sink_template));
+
+  gst_element_class_set_details (gstelement_class, &gst_pitch_details);
+}
+
+static void
+gst_pitch_class_init (GstPitchClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *element_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+  element_class = GST_ELEMENT_CLASS (klass);
+
+  gobject_class->set_property = gst_pitch_set_property;
+  gobject_class->get_property = gst_pitch_get_property;
+  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_pitch_dispose);
+  element_class->change_state = GST_DEBUG_FUNCPTR (gst_pitch_change_state);
+
+  g_object_class_install_property (gobject_class, ARG_PITCH,
+      g_param_spec_float ("pitch", "Pitch",
+          "Audio stream pitch", 0.1, 10.0, 1.0,
+          (GParamFlags) G_PARAM_READWRITE));
+
+  g_object_class_install_property (gobject_class, ARG_TEMPO,
+      g_param_spec_float ("tempo", "Tempo",
+          "Audio stream tempo", 0.1, 10.0, 1.0,
+          (GParamFlags) G_PARAM_READWRITE));
+
+  g_object_class_install_property (gobject_class, ARG_RATE,
+      g_param_spec_float ("rate", "Rate",
+          "Audio stream rate", 0.1, 10.0, 1.0,
+          (GParamFlags) G_PARAM_READWRITE));
+
+  g_type_class_add_private (gobject_class, sizeof (GstPitchPrivate));
+}
+
+static void
+gst_pitch_init (GstPitch * pitch, GstPitchClass * pitch_class)
+{
+  pitch->priv =
+      G_TYPE_INSTANCE_GET_PRIVATE ((pitch), GST_TYPE_PITCH, GstPitchPrivate);
+
+  pitch->sinkpad =
+      gst_pad_new_from_static_template (&gst_pitch_sink_template, "sink");
+  gst_pad_set_chain_function (pitch->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_chain));
+  gst_pad_set_event_function (pitch->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_sink_event));
+  gst_pad_set_setcaps_function (pitch->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_sink_setcaps));
+  gst_pad_set_getcaps_function (pitch->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));
+  gst_element_add_pad (GST_ELEMENT (pitch), pitch->sinkpad);
+
+  pitch->srcpad =
+      gst_pad_new_from_static_template (&gst_pitch_src_template, "src");
+  gst_pad_set_event_function (pitch->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_src_event));
+  gst_pad_set_query_type_function (pitch->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_get_query_types));
+  gst_pad_set_query_function (pitch->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_src_query));
+  gst_pad_set_setcaps_function (pitch->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pitch_sink_setcaps));
+  gst_pad_set_getcaps_function (pitch->srcpad,
+      GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));
+  gst_element_add_pad (GST_ELEMENT (pitch), pitch->srcpad);
+
+  pitch->priv->st = new soundtouch::SoundTouch ();
+
+  pitch->tempo = 1.0;
+  pitch->rate = 1.0;
+  pitch->pitch = 1.0;
+  pitch->next_buffer_time = 0;
+  pitch->next_buffer_offset = 0;
+
+  pitch->priv->st->setRate (pitch->rate);
+  pitch->priv->st->setTempo (pitch->tempo);
+  pitch->priv->st->setPitch (pitch->pitch);
+
+  pitch->priv->stream_time_ratio = 1.0;
+}
+
+
+static void
+gst_pitch_dispose (GObject * object)
+{
+  GstPitch *pitch = GST_PITCH (object);
+
+  if (pitch->priv->st) {
+    delete (pitch->priv->st);
+    pitch->priv->st = NULL;
+  }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+gst_pitch_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstPitch *pitch = GST_PITCH (object);
+
+  GST_OBJECT_LOCK (pitch);
+  switch (prop_id) {
+    case ARG_TEMPO:
+      pitch->tempo = g_value_get_float (value);
+      pitch->priv->stream_time_ratio = pitch->tempo * pitch->rate;
+      pitch->priv->st->setTempo (pitch->tempo);
+      break;
+    case ARG_RATE:
+      pitch->rate = g_value_get_float (value);
+      pitch->priv->stream_time_ratio = pitch->tempo * pitch->rate;
+      pitch->priv->st->setRate (pitch->rate);
+      break;
+    case ARG_PITCH:
+      pitch->pitch = g_value_get_float (value);
+      pitch->priv->st->setPitch (pitch->pitch);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+  GST_OBJECT_UNLOCK (pitch);
+}
+
+static void
+gst_pitch_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstPitch *pitch = GST_PITCH (object);
+
+  GST_OBJECT_LOCK (pitch);
+  switch (prop_id) {
+    case ARG_TEMPO:
+      g_value_set_float (value, pitch->tempo);
+      break;
+    case ARG_RATE:
+      g_value_set_float (value, pitch->rate);
+      break;
+    case ARG_PITCH:
+      g_value_set_float (value, pitch->pitch);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+  GST_OBJECT_UNLOCK (pitch);
+}
+
+static gboolean
+gst_pitch_sink_setcaps (GstPad * pad, GstCaps * caps)
+{
+  GstPitch *pitch;
+  GstPitchPrivate *priv;
+  GstStructure *structure;
+  GstPad *otherpad;
+  gint rate, channels;
+
+  pitch = GST_PITCH (GST_PAD_PARENT (pad));
+  priv = GST_PITCH_GET_PRIVATE (pitch);
+
+  otherpad = (pad == pitch->srcpad) ? pitch->sinkpad : pitch->srcpad;
+
+  if (!gst_pad_set_caps (otherpad, caps))
+    return FALSE;
+
+  structure = gst_caps_get_structure (caps, 0);
+
+  if (!gst_structure_get_int (structure, "rate", &rate) ||
+      !gst_structure_get_int (structure, "channels", &channels)) {
+    return FALSE;
+  }
+
+  GST_OBJECT_LOCK (pitch);
+
+  pitch->samplerate = rate;
+  pitch->channels = channels;
+
+  /* notify the soundtouch instance of this change */
+  priv->st->setSampleRate (rate);
+  priv->st->setChannels (channels);
+
+  /* calculate sample size */
+  pitch->sample_size = (sizeof (gfloat) * channels);
+  pitch->sample_duration = gst_util_uint64_scale_int (GST_SECOND, 1, rate);
+
+  GST_OBJECT_UNLOCK (pitch);
+
+  return TRUE;
+}
+
+/* send a buffer out */
+static GstFlowReturn
+gst_pitch_forward_buffer (GstPitch * pitch, GstBuffer * buffer)
+{
+  gint samples;
+
+  GST_BUFFER_TIMESTAMP (buffer) = pitch->next_buffer_time;
+  pitch->next_buffer_time += GST_BUFFER_DURATION (buffer);
+
+  samples = GST_BUFFER_OFFSET (buffer);
+  GST_BUFFER_OFFSET (buffer) = pitch->next_buffer_offset;
+  pitch->next_buffer_offset += samples;
+  GST_BUFFER_OFFSET_END (buffer) = pitch->next_buffer_offset;
+
+  gst_buffer_set_caps (buffer, GST_PAD_CAPS (pitch->srcpad));
+
+  GST_LOG ("pushing buffer [%" GST_TIME_FORMAT "]-[%" GST_TIME_FORMAT
+      "] (%d samples)", GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
+      GST_TIME_ARGS (pitch->next_buffer_time), samples);
+
+  return gst_pad_push (pitch->srcpad, buffer);
+}
+
+/* extract a buffer from soundtouch */
+static GstBuffer *
+gst_pitch_prepare_buffer (GstPitch * pitch)
+{
+  GstPitchPrivate *priv;
+  guint samples;
+  GstBuffer *buffer;
+
+  priv = GST_PITCH_GET_PRIVATE (pitch);
+
+  GST_LOG_OBJECT (pitch, "preparing buffer");
+
+  samples = pitch->priv->st->numSamples ();
+  if (samples == 0)
+    return NULL;;
+
+  buffer = gst_buffer_new_and_alloc (samples * pitch->sample_size);
+  samples =
+      priv->st->receiveSamples ((gfloat *) GST_BUFFER_DATA (buffer), samples);
+
+  if (samples <= 0)
+    return NULL;
+
+  GST_BUFFER_DURATION (buffer) = samples * pitch->sample_duration;
+  /* temporary store samples here, to avoid having to recalculate this */
+  GST_BUFFER_OFFSET (buffer) = (gint64) samples;
+
+  return buffer;
+}
+
+/* process the last samples, in a later stage we should make sure no more
+ * samples are sent out here as strictly necessary, because soundtouch could
+ * append zero samples, which could disturb looping.  */
+static GstFlowReturn
+gst_pitch_flush_buffer (GstPitch * pitch)
+{
+  GstBuffer *buffer;
+
+  GST_DEBUG_OBJECT (pitch, "flushing buffer");
+
+  if (pitch->next_buffer_offset == 0)
+    return GST_FLOW_OK;
+
+  pitch->priv->st->flush ();
+  buffer = gst_pitch_prepare_buffer (pitch);
+
+  if (!buffer)
+    return GST_FLOW_OK;
+
+  return gst_pitch_forward_buffer (pitch, buffer);
+}
+
+static gboolean
+gst_pitch_src_event (GstPad * pad, GstEvent * event)
+{
+  GstPitch *pitch;
+  gboolean res;
+
+  pitch = GST_PITCH (gst_pad_get_parent (pad));
+
+  GST_DEBUG_OBJECT (pad, "received %s event", GST_EVENT_TYPE_NAME (event));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_SEEK:{
+      /* transform the event upstream, according to the playback rate */
+      gdouble rate;
+      GstFormat format;
+      GstSeekFlags flags;
+      GstSeekType cur_type, stop_type;
+      gint64 cur, stop;
+      gfloat stream_time_ratio;
+
+      GST_OBJECT_LOCK (pitch);
+      stream_time_ratio = pitch->priv->stream_time_ratio;
+      GST_OBJECT_UNLOCK (pitch);
+
+      gst_event_parse_seek (event, &rate, &format, &flags,
+          &cur_type, &cur, &stop_type, &stop);
+
+      cur = (gint64) (cur * stream_time_ratio);
+      stop = (gint64) (stop * stream_time_ratio);
+
+      gst_event_unref (event);
+
+      event = gst_event_new_seek (rate, format, flags,
+          cur_type, cur, stop_type, stop);
+
+      res = gst_pad_event_default (pad, event);
+      break;
+    }
+    default:
+      res = gst_pad_event_default (pad, event);
+      break;
+  }
+
+  gst_object_unref (pitch);
+  return res;
+}
+
+/* generic convert function based on caps, no rate 
+ * used here 
+ */
+static gboolean
+gst_pitch_convert (GstPitch * pitch,
+    GstFormat src_format, gint64 src_value,
+    GstFormat * dst_format, gint64 * dst_value)
+{
+  gboolean res = TRUE;
+  GstClockTime sample_duration;
+  guint sample_size;
+
+  g_return_val_if_fail (dst_format && dst_value, FALSE);
+
+  GST_OBJECT_LOCK (pitch);
+  sample_duration = pitch->sample_duration;
+  sample_size = pitch->sample_size;
+  GST_OBJECT_UNLOCK (pitch);
+
+  if (sample_size == 0 || sample_duration == 0 ||
+      sample_duration == GST_CLOCK_TIME_NONE) {
+    return FALSE;
+  }
+
+  switch (src_format) {
+    case GST_FORMAT_BYTES:
+      switch (*dst_format) {
+        case GST_FORMAT_TIME:
+          *dst_value = src_value / sample_size;
+          *dst_value *= sample_duration;
+          break;
+        case GST_FORMAT_DEFAULT:
+          *dst_value = src_value / sample_size;
+          break;
+        default:
+          res = FALSE;
+          break;
+      }
+      break;
+    case GST_FORMAT_TIME:
+      switch (*dst_format) {
+        case GST_FORMAT_BYTES:
+          *dst_value = src_value / sample_duration;
+          *dst_value *= sample_size;
+          break;
+        case GST_FORMAT_DEFAULT:
+          *dst_value = src_value / sample_duration;
+          break;
+        default:
+          res = FALSE;
+          break;
+      }
+      break;
+    case GST_FORMAT_DEFAULT:
+      switch (*dst_format) {
+        case GST_FORMAT_BYTES:
+          *dst_value = src_value * sample_size;
+          break;
+        case GST_FORMAT_TIME:
+          *dst_value = src_value * sample_duration;
+          break;
+        default:
+          res = FALSE;
+          break;
+      }
+      break;
+    default:
+      res = FALSE;
+      break;
+  }
+
+  return res;
+}
+
+static const GstQueryType *
+gst_pitch_get_query_types (GstPad * pad)
+{
+  static const GstQueryType types[] = {
+    GST_QUERY_POSITION,
+    GST_QUERY_DURATION,
+    GST_QUERY_CONVERT,
+    GST_QUERY_NONE
+  };
+
+  return types;
+}
+
+static gboolean
+gst_pitch_src_query (GstPad * pad, GstQuery * query)
+{
+  GstPitch *pitch;
+  gboolean res = FALSE;
+  gfloat stream_time_ratio;
+  gint64 next_buffer_offset;
+
+  pitch = GST_PITCH (gst_pad_get_parent (pad));
+  GST_LOG ("%s query", GST_QUERY_TYPE_NAME (query));
+  GST_OBJECT_LOCK (pitch);
+  stream_time_ratio = pitch->priv->stream_time_ratio;
+  next_buffer_offset = pitch->next_buffer_offset;
+  GST_OBJECT_UNLOCK (pitch);
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_DURATION:{
+      GstFormat format;
+      gint64 duration;
+
+      if (!gst_pad_query_default (pad, query)) {
+        GST_DEBUG_OBJECT (pitch, "upstream provided no duration");
+        break;
+      }
+
+      gst_query_parse_duration (query, &format, &duration);
+
+      if (format != GST_FORMAT_TIME && format != GST_FORMAT_DEFAULT) {
+        GST_DEBUG_OBJECT (pitch, "not TIME or DEFAULT format");
+        break;
+      }
+      GST_LOG_OBJECT (pitch, "upstream duration: %" G_GINT64_FORMAT, duration);
+      duration = (gint64) (duration / stream_time_ratio);
+      GST_LOG_OBJECT (pitch, "our duration: %" G_GINT64_FORMAT, duration);
+      gst_query_set_duration (query, format, duration);
+      res = TRUE;
+      break;
+    }
+    case GST_QUERY_POSITION:{
+      GstFormat dst_format;
+      gint64 dst_value;
+
+      gst_query_parse_position (query, &dst_format, &dst_value);
+
+      if (dst_format != GST_FORMAT_TIME && dst_format != GST_FORMAT_DEFAULT) {
+        GST_DEBUG_OBJECT (pitch, "not TIME or DEFAULT format");
+        break;
+      }
+
+      if (dst_format != GST_FORMAT_DEFAULT) {
+        res = gst_pitch_convert (pitch, GST_FORMAT_DEFAULT,
+            next_buffer_offset, &dst_format, &dst_value);
+      } else {
+        dst_value = next_buffer_offset;
+        res = TRUE;
+      }
+
+      if (res) {
+        GST_LOG_OBJECT (pitch, "our position: %" G_GINT64_FORMAT, dst_value);
+        gst_query_set_position (query, dst_format, dst_value);
+      }
+      break;
+    }
+    case GST_QUERY_CONVERT:{
+      GstFormat src_format, dst_format;
+      gint64 src_value, dst_value;
+
+      gst_query_parse_convert (query, &src_format, &src_value,
+          &dst_format, NULL);
+
+      res = gst_pitch_convert (pitch, src_format, src_value,
+          &dst_format, &dst_value);
+
+      if (res) {
+        gst_query_set_convert (query, src_format, src_value,
+            dst_format, dst_value);
+      }
+      break;
+    }
+    default:
+      res = gst_pad_query_default (pad, query);
+      break;
+  }
+
+  gst_object_unref (pitch);
+  return res;
+}
+
+
+static gboolean
+gst_pitch_sink_event (GstPad * pad, GstEvent * event)
+{
+  gboolean res = TRUE;
+  GstPitch *pitch;
+
+  pitch = GST_PITCH (gst_pad_get_parent (pad));
+
+  GST_LOG_OBJECT (pad, "received %s event", GST_EVENT_TYPE_NAME (event));
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_NEWSEGMENT:
+    case GST_EVENT_EOS:
+      gst_pitch_flush_buffer (pitch);
+      break;
+    default:
+      break;
+  }
+
+  /* and forward it */
+  res = gst_pad_event_default (pad, event);
+
+  gst_object_unref (pitch);
+  return res;
+}
+
+static GstFlowReturn
+gst_pitch_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstPitch *pitch;
+  GstPitchPrivate *priv;
+
+  pitch = GST_PITCH (GST_PAD_PARENT (pad));
+  priv = GST_PITCH_GET_PRIVATE (pitch);
+
+  /* push the received samples on the soundtouch buffer */
+  GST_LOG_OBJECT (pitch, "incoming buffer (%d samples)",
+      (gint) (GST_BUFFER_SIZE (buffer) / pitch->sample_size));
+
+  priv->st->putSamples ((gfloat *) GST_BUFFER_DATA (buffer),
+      GST_BUFFER_SIZE (buffer) / pitch->sample_size);
+  gst_buffer_unref (buffer);
+
+  /* and try to extract some samples from the soundtouch buffer */
+  if (!priv->st->isEmpty ()) {
+    GstBuffer *out_buffer;
+
+    out_buffer = gst_pitch_prepare_buffer (pitch);
+    return gst_pitch_forward_buffer (pitch, out_buffer);
+  }
+
+  return GST_FLOW_OK;
+}
+
+static GstStateChangeReturn
+gst_pitch_change_state (GstElement * element, GstStateChange transition)
+{
+  GstStateChangeReturn ret;
+  GstPitch *pitch = GST_PITCH (element);
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      break;
+    case GST_STATE_CHANGE_READY_TO_PAUSED:
+      pitch->next_buffer_time = 0;
+      pitch->next_buffer_offset = 0;
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      break;
+    default:
+      break;
+  }
+
+  ret = parent_class->change_state (element, transition);
+  if (ret != GST_STATE_CHANGE_SUCCESS)
+    return ret;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+    case GST_STATE_CHANGE_READY_TO_NULL:
+    default:
+      break;
+  }
+
+  return ret;
+}
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (pitch_debug, "pitch", 0,
+      "audio pitch control element");
+
+  return gst_element_register (plugin, "pitch", GST_RANK_NONE, GST_TYPE_PITCH);
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "soundtouch",
+    "Audio Pitch Controller",
+    plugin_init, VERSION, "LGPL", GST_PACKAGE, GST_ORIGIN)
diff --git a/ext/soundtouch/gstpitch.hh b/ext/soundtouch/gstpitch.hh
new file mode 100644
index 000000000..24d42ba2f
--- /dev/null
+++ b/ext/soundtouch/gstpitch.hh
@@ -0,0 +1,88 @@
+/* GStreamer pitch controller element
+ * Copyright (C) 2006 Wouter Paesen <wouter@blue-gate.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __GST_PITCH_H__
+#define __GST_PITCH_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_PITCH \
+  (gst_pitch_get_type())
+#define GST_PITCH(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PITCH,GstPitch))
+#define GST_PITCH_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PITCH,GstPitchClass))
+#define GST_IS_PITCH(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PITCH))
+#define GST_IS_PITCH_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PITCH))
+
+typedef struct _GstPitch            GstPitch;
+typedef struct _GstPitchClass       GstPitchClass;
+typedef struct _GstPitchPrivate     GstPitchPrivate;
+
+
+struct _GstPitch
+{
+  GstElement element;
+
+  GstPad  *srcpad;
+  GstPad  *sinkpad;
+
+  /* parameter values */
+  gfloat   tempo;               /* time stretch 
+                                 * change the duration, without affecting the pitch
+                                 * > 1 makes the stream shorter
+                                 */
+
+  gfloat   rate;                /* change playback rate 
+                                 * resample
+                                 * > 1 makes the stream shorter
+                                 */
+
+  gfloat   pitch;               /* change pitch 
+                                 * change the pitch without affecting the
+                                 * duration, stream length doesn't change
+                                 */
+
+  /* values extracted from caps */
+  gint          samplerate;      /* samplerate                           */
+  gint          channels;        /* number of audio channels             */
+  gsize         sample_size;     /* number of bytes for a single sample  */
+  GstClockTime  sample_duration; /* time for 1 sample                    */
+
+  /* stream tracking */
+  GstClockTime  next_buffer_time;
+  gint64        next_buffer_offset;
+
+  GstPitchPrivate *priv;
+};
+
+struct _GstPitchClass 
+{
+  GstElementClass parent_class;
+};
+
+GType gst_pitch_get_type (void);
+
+G_END_DECLS
+
+#endif /* __GST_PITCH_H__ */