Add scaletempo plugin, which allows to scale the speed of audio without changing the pitch by handling seeks with a r...

Original commit message from CVS:
Patch by: Rov Juvano <rovjuvano at users dot sourceforge dot net>
* configure.ac:
* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-bad-plugins-docs.sgml:
* docs/plugins/gst-plugins-bad-plugins-sections.txt:
* docs/plugins/inspect/plugin-scaletempo.xml:
* examples/scaletempo/Makefile.am:
* examples/scaletempo/demo-gui.c: (pop_status_bar),
(status_bar_printf), (demo_gui_seek_bar_format), (update_position),
(demo_gui_seek_bar_change), (demo_gui_do_change_rate),
(demo_gui_do_set_rate), (demo_gui_do_rate_entered),
(demo_gui_do_toggle_advanced), (demo_gui_do_toggle_disabled),
(demo_gui_do_seek), (demo_gui_do_play), (demo_gui_do_pause),
(demo_gui_do_play_pause), (demo_gui_do_open_file),
(demo_gui_do_playlist_prev), (demo_gui_do_playlist_next),
(demo_gui_do_about_dialog), (demo_gui_do_quit),
(demo_gui_request_set_stride), (demo_gui_request_set_overlap),
(demo_gui_request_set_search), (demo_gui_rate_changed),
(demo_gui_playing_started), (demo_gui_playing_paused),
(demo_gui_playing_ended), (demo_gui_player_errored),
(demo_gui_stride_changed), (demo_gui_overlap_changed),
(demo_gui_search_changed), (demo_gui_set_player_func),
(demo_gui_set_playlist_func), (build_gvalue_array),
(create_action), (demo_gui_show_func), (demo_gui_set_player),
(demo_gui_set_playlist), (demo_gui_show), (demo_gui_get_property),
(demo_gui_set_property), (demo_gui_init), (demo_gui_class_init),
(demo_gui_get_type):
* examples/scaletempo/demo-gui.h:
* examples/scaletempo/demo-main.c: (handle_error_message),
(handle_quit), (main):
* examples/scaletempo/demo-player.c: (no_pipeline),
(demo_player_event_listener), (demo_player_state_changed_cb),
(demo_player_eos_cb), (demo_player_build_pipeline), (_set_rate),
(demo_player_scale_rate_func), (demo_player_set_rate_func),
(_set_state_and_wait), (demo_player_load_uri_func),
(demo_player_play_func), (demo_player_pause_func), (_seek_to),
(demo_player_seek_by_func), (demo_player_seek_to_func),
(demo_player_get_position_func), (demo_player_get_duration_func),
(demo_player_scale_rate), (demo_player_set_rate),
(demo_player_load_uri), (demo_player_play), (demo_player_pause),
(demo_player_seek_by), (demo_player_seek_to),
(demo_player_get_position), (demo_player_get_duration),
(demo_player_get_property), (demo_player_set_property),
(demo_player_init), (demo_player_class_init),
(demo_player_get_type):
* examples/scaletempo/demo-player.h:
* gst/scaletempo/Makefile.am:
* gst/scaletempo/gstscaletempo.c: (best_overlap_offset_float),
(best_overlap_offset_s16), (output_overlap_float),
(output_overlap_s16), (fill_queue), (reinit_buffers),
(gst_scaletempo_transform), (gst_scaletempo_transform_size),
(gst_scaletempo_sink_event), (gst_scaletempo_set_caps),
(gst_scaletempo_get_property), (gst_scaletempo_set_property),
(gst_scaletempo_base_init), (gst_scaletempo_class_init),
(gst_scaletempo_init):
* gst/scaletempo/gstscaletempo.h:
* gst/scaletempo/gstscaletempoplugin.c: (plugin_init):
Add scaletempo plugin, which allows to scale the speed of audio without
changing the pitch by handling seeks with a rate!=1.0.
Integrate it into the docs and add the example application for it.
Fixes bug #537700.

4 files changed, 884 insertions, 0 deletions

diff --git a/gst/scaletempo/Makefile.am b/gst/scaletempo/Makefile.am
new file mode 100644
index 000000000..a3c83993e
--- /dev/null
+++ b/gst/scaletempo/Makefile.am
@@ -0,0 +1,13 @@
+plugin_LTLIBRARIES = libgstscaletempoplugin.la
+
+# sources used to compile this plug-in
+libgstscaletempoplugin_la_SOURCES = gstscaletempoplugin.c gstscaletempo.c
+
+# flags used to compile this plugin
+# add other _CFLAGS and _LIBS as needed
+libgstscaletempoplugin_la_CFLAGS = $(GST_CFLAGS)
+libgstscaletempoplugin_la_LIBADD = $(GST_LIBS) $(GST_BASE_LIBS)
+libgstscaletempoplugin_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+
+# headers we need but don't want installed
+noinst_HEADERS = gstscaletempo.h
diff --git a/gst/scaletempo/gstscaletempo.c b/gst/scaletempo/gstscaletempo.c
new file mode 100644
index 000000000..923c2fd1e
--- /dev/null
+++ b/gst/scaletempo/gstscaletempo.c
@@ -0,0 +1,748 @@
+/*
+ * GStreamer
+ * Copyright (C) 2008 Rov Juvano <rovjuvano@users.sourceforge.net>
+ *
+ * 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:element-scaletempo
+ *
+ * <refsect2>
+ * <para>
+ * Scale tempo while maintaining pitch
+ * (WSOLA-like technique with cross correlation)
+ * Inspired by SoundTouch library by Olli Parviainen
+ * </para>
+ * <para>
+ * Use Sceletempo to apply playback rates without the chipmunk effect.
+ * </para>
+ * <title>Example pipelines</title>
+ * <para>
+ * <programlisting>
+ * filesrc location=media.ext ! decodebin name=d \
+ *     d. ! queue ! audioconvert ! audioresample ! scaletempo ! audioconvert ! audioresample ! autoaudiosink \
+ *     d. ! queue ! ffmpegcolorspace ! autovideosink
+ * </programlisting>
+ * OR
+ * <programlisting>
+ * playbin uri=... audio_sink="scaletempo ! audioconvert ! audioresample ! autoaudiosink"
+ * </programlisting>
+ * When an application sends a seek event with rate != 1.0, Scaletempo applies
+ * the rate change by scaling the tempo without scaling the pitch.
+ * </para>
+ * <para>
+ * Scaletempo works by producing audio in constant sized chunks (a "stride") but
+ * consuming chunks proportional to the playback rate.
+ * </para>
+ * <para>
+ * Scaletempo then smooths the output by blending the end of one stride with
+ * the next ("overlap").
+ * </para>
+ * <para>
+ * Scaletempo smooths the overlap further by searching within the input buffer
+ * for the best overlap position.  Scaletempo uses a statistical cross correlation
+ * (roughly a dot-product).  Scaletempo consumes most of its CPU cycles here.
+ * </para>
+ * </refsect2>
+ */
+
+/*
+ * Note: frame = audio key unit (i.e. one sample for each channel)
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <gst/base/gstbasetransform.h>
+#include <string.h>             /* for memset */
+
+#include "gstscaletempo.h"
+
+GST_DEBUG_CATEGORY_STATIC (gst_scaletempo_debug);
+#define GST_CAT_DEFAULT gst_scaletempo_debug
+
+/* Filter signals and args */
+enum
+{
+  LAST_SIGNAL
+};
+
+enum
+{
+  PROP_0,
+  PROP_RATE,
+  PROP_STRIDE,
+  PROP_OVERLAP,
+  PROP_SEARCH,
+};
+
+#define SUPPORTED_CAPS \
+GST_STATIC_CAPS ( \
+    "audio/x-raw-float, " \
+      "rate = (int) [ 1, MAX ], "       \
+      "channels = (int) [ 1, MAX ], " \
+      "endianness = (int) BYTE_ORDER, " \
+      "width = (int) 32;" \
+    "audio/x-raw-int, " \
+      "rate = (int) [ 1, MAX ], " \
+      "channels = (int) [ 1, MAX ], " \
+      "endianness = (int) BYTE_ORDER, " \
+      "width = (int) 16, " \
+      "depth = (int) 16, " \
+      "signed = (boolean) true;" \
+)
+
+static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    SUPPORTED_CAPS);
+
+static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    SUPPORTED_CAPS);
+
+#define DEBUG_INIT(bla) GST_DEBUG_CATEGORY_INIT (gst_scaletempo_debug, "scaletempo", 0, "scaletempo element");
+
+GST_BOILERPLATE_FULL (GstScaletempo, gst_scaletempo, GstBaseTransform,
+    GST_TYPE_BASE_TRANSFORM, DEBUG_INIT);
+
+typedef struct _GstScaletempoPrivate
+{
+  gdouble scale;
+  /* parameters */
+  guint ms_stride;
+  gdouble percent_overlap;
+  guint ms_search;
+  /* caps */
+  gboolean use_int;
+  guint samples_per_frame;      /* AKA number of channels */
+  guint bytes_per_sample;
+  guint bytes_per_frame;
+  guint sample_rate;
+  /* stride */
+  gdouble frames_stride_scaled;
+  gdouble frames_stride_error;
+  guint bytes_stride;
+  gdouble bytes_stride_scaled;
+  guint bytes_queue_max;
+  guint bytes_queued;
+  guint bytes_to_slide;
+  gint8 *buf_queue;
+  /* overlap */
+  guint samples_overlap;
+  guint samples_standing;
+  guint bytes_overlap;
+  guint bytes_standing;
+  gpointer buf_overlap;
+  gpointer table_blend;
+  void (*output_overlap) (GstScaletempo * scaletempo, gpointer out_buf,
+      guint bytes_off);
+  /* best overlap */
+  guint frames_search;
+  gpointer buf_pre_corr;
+  gpointer table_window;
+    guint (*best_overlap_offset) (GstScaletempo * scaletempo);
+  /* gstreamer */
+  gint64 segment_start;
+  /* threads */
+  gboolean reinit_buffers;
+} GstScaletempoPrivate;
+#define GST_SCALETEMPO_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), GST_TYPE_SCALETEMPO, GstScaletempoPrivate))
+
+
+static guint
+best_overlap_offset_float (GstScaletempo * scaletempo)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  gfloat *pw, *po, *ppc, *search_start;
+  gfloat best_corr = G_MININT;
+  guint best_off = 0;
+  gint i, off;
+
+  pw = p->table_window;
+  po = p->buf_overlap;
+  po += p->samples_per_frame;
+  ppc = p->buf_pre_corr;
+  for (i = p->samples_per_frame; i < p->samples_overlap; i++) {
+    *ppc++ = *pw++ * *po++;
+  }
+
+  search_start = (gfloat *) p->buf_queue + p->samples_per_frame;
+  for (off = 0; off < p->frames_search; off++) {
+    gfloat corr = 0;
+    gfloat *ps = search_start;
+    ppc = p->buf_pre_corr;
+    for (i = p->samples_per_frame; i < p->samples_overlap; i++) {
+      corr += *ppc++ * *ps++;
+    }
+    if (corr > best_corr) {
+      best_corr = corr;
+      best_off = off;
+    }
+    search_start += p->samples_per_frame;
+  }
+
+  return best_off * p->bytes_per_frame;
+}
+
+/* buffer padding for loop optimization: sizeof(gint32) * (loop_size - 1) */
+#define UNROLL_PADDING (4*3)
+static guint
+best_overlap_offset_s16 (GstScaletempo * scaletempo)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  gint32 *pw, *ppc;
+  gint16 *po, *search_start;
+  gint64 best_corr = G_MININT64;
+  guint best_off = 0;
+  guint off;
+  glong i;
+
+  pw = p->table_window;
+  po = p->buf_overlap;
+  po += p->samples_per_frame;
+  ppc = p->buf_pre_corr;
+  for (i = p->samples_per_frame; i < p->samples_overlap; i++) {
+    *ppc++ = (*pw++ * *po++) >> 15;
+  }
+
+  search_start = (gint16 *) p->buf_queue + p->samples_per_frame;
+  for (off = 0; off < p->frames_search; off++) {
+    gint64 corr = 0;
+    gint16 *ps = search_start;
+    ppc = p->buf_pre_corr;
+    ppc += p->samples_overlap - p->samples_per_frame;
+    ps += p->samples_overlap - p->samples_per_frame;
+    i = -(p->samples_overlap - p->samples_per_frame);
+    do {
+      corr += ppc[i + 0] * ps[i + 0];
+      corr += ppc[i + 1] * ps[i + 1];
+      corr += ppc[i + 2] * ps[i + 2];
+      corr += ppc[i + 3] * ps[i + 3];
+      i += 4;
+    } while (i < 0);
+    if (corr > best_corr) {
+      best_corr = corr;
+      best_off = off;
+    }
+    search_start += p->samples_per_frame;
+  }
+
+  return best_off * p->bytes_per_frame;
+}
+
+static void
+output_overlap_float (GstScaletempo * scaletempo,
+    gpointer buf_out, guint bytes_off)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  gfloat *pout = buf_out;
+  gfloat *pb = p->table_blend;
+  gfloat *po = p->buf_overlap;
+  gfloat *pin = (gfloat *) (p->buf_queue + bytes_off);
+  gint i;
+  for (i = 0; i < p->samples_overlap; i++) {
+    *pout++ = *po - *pb++ * (*po - *pin++);
+    po++;
+  }
+}
+
+static void
+output_overlap_s16 (GstScaletempo * scaletempo,
+    gpointer buf_out, guint bytes_off)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  gint16 *pout = buf_out;
+  gint32 *pb = p->table_blend;
+  gint16 *po = p->buf_overlap;
+  gint16 *pin = (gint16 *) (p->buf_queue + bytes_off);
+  gint i;
+  for (i = 0; i < p->samples_overlap; i++) {
+    *pout++ = *po - ((*pb++ * (*po - *pin++)) >> 16);
+    po++;
+  }
+}
+
+static guint
+fill_queue (GstScaletempo * scaletempo, GstBuffer * buf_in, guint offset)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  guint bytes_in = GST_BUFFER_SIZE (buf_in) - offset;
+  guint offset_unchanged = offset;
+
+  if (p->bytes_to_slide > 0) {
+    if (p->bytes_to_slide < p->bytes_queued) {
+      guint bytes_in_move = p->bytes_queued - p->bytes_to_slide;
+      memmove (p->buf_queue, p->buf_queue + p->bytes_to_slide, bytes_in_move);
+      p->bytes_to_slide = 0;
+      p->bytes_queued = bytes_in_move;
+    } else {
+      guint bytes_in_skip;
+      p->bytes_to_slide -= p->bytes_queued;
+      bytes_in_skip = MIN (p->bytes_to_slide, bytes_in);
+      p->bytes_queued = 0;
+      p->bytes_to_slide -= bytes_in_skip;
+      offset += bytes_in_skip;
+      bytes_in -= bytes_in_skip;
+    }
+  }
+
+  if (bytes_in > 0) {
+    guint bytes_in_copy = MIN (p->bytes_queue_max - p->bytes_queued, bytes_in);
+    memcpy (p->buf_queue + p->bytes_queued,
+        GST_BUFFER_DATA (buf_in) + offset, bytes_in_copy);
+    p->bytes_queued += bytes_in_copy;
+    offset += bytes_in_copy;
+  }
+
+  return offset - offset_unchanged;
+}
+
+static void
+reinit_buffers (GstScaletempo * scaletempo)
+{
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  gint i, j;
+  guint frames_overlap;
+  guint new_size;
+
+  guint frames_stride = p->ms_stride * p->sample_rate / 1000.0;
+  p->bytes_stride = frames_stride * p->bytes_per_frame;
+
+  /* overlap */
+  frames_overlap = frames_stride * p->percent_overlap;
+  if (frames_overlap < 1) {     /* if no overlap */
+    p->bytes_overlap = 0;
+    p->bytes_standing = p->bytes_stride;
+    p->samples_standing = p->bytes_standing / p->bytes_per_sample;
+    p->output_overlap = NULL;
+  } else {
+    guint prev_overlap = p->bytes_overlap;
+    p->bytes_overlap = frames_overlap * p->bytes_per_frame;
+    p->samples_overlap = frames_overlap * p->samples_per_frame;
+    p->bytes_standing = p->bytes_stride - p->bytes_overlap;
+    p->samples_standing = p->bytes_standing / p->bytes_per_sample;
+    p->buf_overlap = g_realloc (p->buf_overlap, p->bytes_overlap);
+    p->table_blend = g_realloc (p->table_blend, p->samples_overlap * 4);        /* sizeof (gint32|gfloat) */
+    if (p->bytes_overlap > prev_overlap) {
+      memset (p->buf_overlap + prev_overlap, 0,
+          p->bytes_overlap - prev_overlap);
+    }
+    if (p->use_int) {
+      gint32 *pb = p->table_blend;
+      gint64 blend = 0;
+      for (i = 0; i < frames_overlap; i++) {
+        gint32 v = blend / frames_overlap;
+        for (j = 0; j < p->samples_per_frame; j++) {
+          *pb++ = v;
+        }
+        blend += 65535;         /* 2^16 */
+      }
+      p->output_overlap = output_overlap_s16;
+    } else {
+      gfloat *pb = p->table_blend;
+      gfloat t = (gfloat) frames_overlap;
+      for (i = 0; i < frames_overlap; i++) {
+        gfloat v = i / t;
+        for (j = 0; j < p->samples_per_frame; j++) {
+          *pb++ = v;
+        }
+      }
+      p->output_overlap = output_overlap_float;
+    }
+  }
+
+  /* best overlap */
+  p->frames_search =
+      (frames_overlap <= 1) ? 0 : p->ms_search * p->sample_rate / 1000.0;
+  if (p->frames_search < 1) {   /* if no search */
+    p->best_overlap_offset = NULL;
+  } else {
+    guint bytes_pre_corr = (p->samples_overlap - p->samples_per_frame) * 4;     /* sizeof (gint32|gfloat) */
+    p->buf_pre_corr =
+        g_realloc (p->buf_pre_corr, bytes_pre_corr + UNROLL_PADDING);
+    p->table_window = g_realloc (p->table_window, bytes_pre_corr);
+    if (p->use_int) {
+      gint64 t = frames_overlap;
+      gint32 n = 8589934588LL / (t * t);        /* 4 * (2^31 - 1) / t^2 */
+      gint32 *pw;
+
+      memset (p->buf_pre_corr + bytes_pre_corr, 0, UNROLL_PADDING);
+      pw = p->table_window;
+      for (i = 1; i < frames_overlap; i++) {
+        gint32 v = (i * (t - i) * n) >> 15;
+        for (j = 0; j < p->samples_per_frame; j++) {
+          *pw++ = v;
+        }
+      }
+      p->best_overlap_offset = best_overlap_offset_s16;
+    } else {
+      gfloat *pw = p->table_window;
+      for (i = 1; i < frames_overlap; i++) {
+        gfloat v = i * (frames_overlap - i);
+        for (j = 0; j < p->samples_per_frame; j++) {
+          *pw++ = v;
+        }
+      }
+      p->best_overlap_offset = best_overlap_offset_float;
+    }
+  }
+
+  new_size =
+      (p->frames_search + frames_stride + frames_overlap) * p->bytes_per_frame;
+  if (p->bytes_queued > new_size) {
+    if (p->bytes_to_slide > p->bytes_queued) {
+      p->bytes_to_slide -= p->bytes_queued;
+      p->bytes_queued = 0;
+    } else {
+      guint new_queued = MIN (p->bytes_queued - p->bytes_to_slide, new_size);
+      memmove (p->buf_queue,
+          p->buf_queue + p->bytes_queued - new_queued, new_queued);
+      p->bytes_to_slide = 0;
+      p->bytes_queued = new_queued;
+    }
+  }
+  p->bytes_queue_max = new_size;
+  p->buf_queue = g_realloc (p->buf_queue, p->bytes_queue_max);
+
+  p->bytes_stride_scaled = p->bytes_stride * p->scale;
+  p->frames_stride_scaled = p->bytes_stride_scaled / p->bytes_per_frame;
+
+  GST_DEBUG
+      ("%.3f scale, %.3f stride_in, %i stride_out, %i standing, %i overlap, %i search, %i queue, %s mode",
+      p->scale, p->frames_stride_scaled,
+      (gint) (p->bytes_stride / p->bytes_per_frame),
+      (gint) (p->bytes_standing / p->bytes_per_frame),
+      (gint) (p->bytes_overlap / p->bytes_per_frame), p->frames_search,
+      (gint) (p->bytes_queue_max / p->bytes_per_frame),
+      (p->use_int ? "s16" : "float"));
+
+  p->reinit_buffers = FALSE;
+}
+
+
+/* GstBaseTransform vmethod implementations */
+static GstFlowReturn
+gst_scaletempo_transform (GstBaseTransform * trans,
+    GstBuffer * inbuf, GstBuffer * outbuf)
+{
+  GstScaletempo *scaletempo = GST_SCALETEMPO (trans);
+  GstScaletempoPrivate *p = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+
+  gint8 *pout = (gint8 *) GST_BUFFER_DATA (outbuf);
+  guint offset_in = fill_queue (scaletempo, inbuf, 0);
+  guint bytes_out = 0;
+  while (p->bytes_queued >= p->bytes_queue_max) {
+    guint bytes_off = 0;
+    gdouble frames_to_slide;
+    guint frames_to_stride_whole;
+
+    // output stride
+    if (p->output_overlap) {
+      if (p->best_overlap_offset) {
+        bytes_off = p->best_overlap_offset (scaletempo);
+      }
+      p->output_overlap (scaletempo, pout, bytes_off);
+    }
+    memcpy (pout + p->bytes_overlap,
+        p->buf_queue + bytes_off + p->bytes_overlap, p->bytes_standing);
+    pout += p->bytes_stride;
+    bytes_out += p->bytes_stride;
+
+    // input stride
+    memcpy (p->buf_overlap,
+        p->buf_queue + bytes_off + p->bytes_stride, p->bytes_overlap);
+    frames_to_slide = p->frames_stride_scaled + p->frames_stride_error;
+    frames_to_stride_whole = (gint) frames_to_slide;
+    p->bytes_to_slide = frames_to_stride_whole * p->bytes_per_frame;
+    p->frames_stride_error = frames_to_slide - frames_to_stride_whole;
+
+    offset_in += fill_queue (scaletempo, inbuf, offset_in);
+  }
+
+  GST_BUFFER_SIZE (outbuf) = bytes_out;
+  GST_BUFFER_TIMESTAMP (outbuf) =
+      (GST_BUFFER_TIMESTAMP (outbuf) - p->segment_start) / p->scale +
+      p->segment_start;
+  //GST_BUFFER_DURATION (outbuf)  = bytes_out * GST_SECOND / (p->bytes_per_frame * p->sample_rate);
+  return GST_FLOW_OK;
+}
+
+static gboolean
+gst_scaletempo_transform_size (GstBaseTransform * trans,
+    GstPadDirection direction,
+    GstCaps * caps, guint size, GstCaps * othercaps, guint * othersize)
+{
+  if (direction == GST_PAD_SINK) {
+    GstScaletempo *scaletempo = GST_SCALETEMPO (trans);
+    GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+    gint bytes_to_out;
+
+    if (priv->reinit_buffers)
+      reinit_buffers (scaletempo);
+
+    bytes_to_out = size + priv->bytes_queued - priv->bytes_to_slide;
+    if (bytes_to_out < (gint) priv->bytes_queue_max) {
+      *othersize = 0;
+    } else {
+      /* while (total_buffered - stride_length * n >= queue_max) n++ */
+      *othersize = priv->bytes_stride * ((guint) (
+              (bytes_to_out - priv->bytes_queue_max +
+                  /* rounding protection */ priv->bytes_per_frame)
+              / priv->bytes_stride_scaled) + 1);
+    }
+
+    return TRUE;
+  }
+  return FALSE;
+}
+
+static gboolean
+gst_scaletempo_sink_event (GstBaseTransform * trans, GstEvent * event)
+{
+  if (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT) {
+    GstScaletempo *scaletempo = GST_SCALETEMPO (trans);
+    GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+
+    gboolean update;
+    gdouble rate, applied_rate;
+    GstFormat format;
+    gint64 start, stop, position;
+
+    gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
+        &format, &start, &stop, &position);
+
+    if (priv->scale != rate) {
+      if (ABS (rate - 1.0) < 1e-10) {
+        priv->scale = 1.0;
+        gst_base_transform_set_passthrough (GST_BASE_TRANSFORM (scaletempo),
+            TRUE);
+      } else {
+        gst_base_transform_set_passthrough (GST_BASE_TRANSFORM (scaletempo),
+            FALSE);
+        priv->scale = rate;
+        priv->bytes_stride_scaled = priv->bytes_stride * priv->scale;
+        priv->frames_stride_scaled =
+            priv->bytes_stride_scaled / priv->bytes_per_frame;
+        GST_DEBUG ("%.3f scale, %.3f stride_in, %i stride_out", priv->scale,
+            priv->frames_stride_scaled,
+            (gint) (priv->bytes_stride / priv->bytes_per_frame));
+
+        priv->bytes_to_slide = 0;
+      }
+    }
+
+    if (priv->scale != 1.0) {
+      priv->segment_start = start;
+      applied_rate = priv->scale;
+      rate = 1.0;
+      //gst_event_unref (event);
+      event = gst_event_new_new_segment_full (update, rate, applied_rate,
+          format, start, stop, position);
+      gst_pad_push_event (GST_BASE_TRANSFORM_SRC_PAD (trans), event);
+      return FALSE;
+    }
+  }
+  parent_class->event (trans, event);
+  return TRUE;
+}
+
+static gboolean
+gst_scaletempo_set_caps (GstBaseTransform * trans,
+    GstCaps * incaps, GstCaps * outcaps)
+{
+  GstScaletempo *scaletempo = GST_SCALETEMPO (trans);
+  GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  GstStructure *s = gst_caps_get_structure (incaps, 0);
+
+  gint width, bps, nch, rate;
+  gboolean use_int;
+  const gchar *type = gst_structure_get_name (s);
+  if (g_str_equal (type, "audio/x-raw-int")) {
+    use_int = TRUE;
+    gst_structure_get_int (s, "depth", &width);
+  } else if (g_str_equal (type, "audio/x-raw-float")) {
+    use_int = FALSE;
+    gst_structure_get_int (s, "width", &width);
+  } else {
+    return FALSE;
+  }
+  bps = width / 8;
+
+  gst_structure_get_int (s, "channels", &nch);
+  gst_structure_get_int (s, "rate", &rate);
+
+  GST_DEBUG ("caps: %s seek, "
+      "%5" G_GUINT32_FORMAT " rate, "
+      "%2" G_GUINT32_FORMAT " nch, "
+      "%2" G_GUINT32_FORMAT " bps", type, rate, nch, bps);
+
+  if (rate != priv->sample_rate
+      || nch != priv->samples_per_frame
+      || bps != priv->bytes_per_sample || use_int != priv->use_int) {
+    priv->sample_rate = rate;
+    priv->samples_per_frame = nch;
+    priv->bytes_per_sample = bps;
+    priv->bytes_per_frame = nch * bps;
+    priv->use_int = use_int;
+    priv->reinit_buffers = TRUE;
+  }
+
+  return TRUE;
+}
+
+
+/* GObject vmethod implementations */
+static void
+gst_scaletempo_get_property (GObject * object,
+    guint prop_id, GValue * value, GParamSpec * pspec)
+{
+  GstScaletempo *scaletempo = GST_SCALETEMPO (object);
+  GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+
+  switch (prop_id) {
+    case PROP_RATE:
+      g_value_set_double (value, priv->scale);
+      break;
+    case PROP_STRIDE:
+      g_value_set_uint (value, priv->ms_stride);
+      break;
+    case PROP_OVERLAP:
+      g_value_set_double (value, priv->percent_overlap);
+      break;
+    case PROP_SEARCH:
+      g_value_set_uint (value, priv->ms_search);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_scaletempo_set_property (GObject * object,
+    guint prop_id, const GValue * value, GParamSpec * pspec)
+{
+  GstScaletempo *scaletempo = GST_SCALETEMPO (object);
+  GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+
+  switch (prop_id) {
+    case PROP_STRIDE:{
+      guint new_value = g_value_get_uint (value);
+      if (priv->ms_stride != new_value) {
+        priv->ms_stride = new_value;
+        priv->reinit_buffers = TRUE;
+      }
+      break;
+    }
+    case PROP_OVERLAP:{
+      gdouble new_value = g_value_get_double (value);
+      if (priv->percent_overlap != new_value) {
+        priv->percent_overlap = new_value;
+        priv->reinit_buffers = TRUE;
+      }
+      break;
+    }
+    case PROP_SEARCH:{
+      guint new_value = g_value_get_uint (value);
+      if (priv->ms_search != new_value) {
+        priv->ms_search = new_value;
+        priv->reinit_buffers = TRUE;
+      }
+      break;
+    }
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_scaletempo_base_init (gpointer klass)
+{
+  static GstElementDetails element_details = {
+    "Scaletempo",
+    "Filter/Effect/Rate",
+    "Sync audio tempo with playback rate",
+    "Rov Juvano <rovjuvano@users.sourceforge.net>"
+  };
+  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&src_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&sink_template));
+  gst_element_class_set_details (element_class, &element_details);
+}
+
+static void
+gst_scaletempo_class_init (GstScaletempoClass * klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  GstBaseTransformClass *basetransform_class = GST_BASE_TRANSFORM_CLASS (klass);
+
+  g_type_class_add_private (klass, sizeof (GstScaletempoPrivate));
+
+  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_scaletempo_get_property);
+  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_scaletempo_set_property);
+
+  g_object_class_install_property (gobject_class, PROP_RATE,
+      g_param_spec_double ("rate", "Playback Rate", "Current playback rate",
+          G_MININT, G_MAXINT, 1.0, G_PARAM_READABLE));
+
+  g_object_class_install_property (gobject_class, PROP_STRIDE,
+      g_param_spec_uint ("stride", "Stride Length",
+          "Length in milliseconds to output each stride", 1, 5000, 30,
+          G_PARAM_READWRITE));
+
+  g_object_class_install_property (gobject_class, PROP_OVERLAP,
+      g_param_spec_double ("overlap", "Overlap Length",
+          "Percentage of stride to overlap", 0, 1, .2, G_PARAM_READWRITE));
+
+  g_object_class_install_property (gobject_class, PROP_SEARCH,
+      g_param_spec_uint ("search", "Search Length",
+          "Length in milliseconds to search for best overlap position", 0, 500,
+          14, G_PARAM_READWRITE));
+
+  basetransform_class->event = GST_DEBUG_FUNCPTR (gst_scaletempo_sink_event);
+  basetransform_class->set_caps = GST_DEBUG_FUNCPTR (gst_scaletempo_set_caps);
+  basetransform_class->transform_size =
+      GST_DEBUG_FUNCPTR (gst_scaletempo_transform_size);
+  basetransform_class->transform = GST_DEBUG_FUNCPTR (gst_scaletempo_transform);
+}
+
+static void
+gst_scaletempo_init (GstScaletempo * scaletempo, GstScaletempoClass * klass)
+{
+  GstScaletempoPrivate *priv = GST_SCALETEMPO_GET_PRIVATE (scaletempo);
+  /* defaults */
+  priv->ms_stride = 30;
+  priv->percent_overlap = .2;
+  priv->ms_search = 14;
+
+  /* uninitialized */
+  priv->scale = 0;
+  priv->sample_rate = 0;
+  priv->frames_stride_error = 0;
+  priv->bytes_stride = 0;
+  priv->bytes_queued = 0;
+  priv->bytes_to_slide = 0;
+  priv->segment_start = 0;
+}
diff --git a/gst/scaletempo/gstscaletempo.h b/gst/scaletempo/gstscaletempo.h
new file mode 100644
index 000000000..af2e8bbf2
--- /dev/null
+++ b/gst/scaletempo/gstscaletempo.h
@@ -0,0 +1,49 @@
+/*
+ * GStreamer
+ * Copyright (C) 2008 Rov Juvano <rovjuvano@users.sourceforge.net>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_SCALETEMPO_H__
+#define __GST_SCALETEMPO_H__
+
+#include <gst/gst.h>
+#include <gst/base/gstbasetransform.h>
+
+G_BEGIN_DECLS
+#define GST_TYPE_SCALETEMPO            (gst_scaletempo_get_type())
+#define GST_SCALETEMPO(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj), GST_TYPE_SCALETEMPO, GstScaletempo))
+#define GST_SCALETEMPO_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),  GST_TYPE_SCALETEMPO, GstScaletempoClass))
+#define GST_IS_SCALETEMPO(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), GST_TYPE_SCALETEMPO))
+#define GST_IS_SCALETEMPO_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),  GST_TYPE_SCALETEMPO))
+typedef struct _GstScaletempo GstScaletempo;
+typedef struct _GstScaletempoClass GstScaletempoClass;
+
+struct _GstScaletempo
+{
+  GstBaseTransform element;
+};
+
+struct _GstScaletempoClass
+{
+  GstBaseTransformClass parent_class;
+};
+
+GType gst_scaletempo_get_type (void);
+
+G_END_DECLS
+#endif /* __GST_SCALETEMPO_H__ */
diff --git a/gst/scaletempo/gstscaletempoplugin.c b/gst/scaletempo/gstscaletempoplugin.c
new file mode 100644
index 000000000..24e16e8f6
--- /dev/null
+++ b/gst/scaletempo/gstscaletempoplugin.c
@@ -0,0 +1,74 @@
+/*
+ * GStreamer
+ * Copyright (C) 2008 Rov Juvano <rovjuvano@users.sourceforge.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Alternatively, the contents of this file may be used under the
+ * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
+ * which case the following provisions apply instead of the ones
+ * mentioned above:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <gst/gst.h>
+#include "gstscaletempo.h"
+
+/* entry point to initialize the plug-in
+ * initialize the plug-in itself
+ * register the element factories and pad templates
+ * register the features
+ *
+ * exchange the string 'plugin' with your elemnt name
+ */
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  return gst_element_register (plugin, "scaletempo", GST_RANK_NONE,
+      GST_TYPE_SCALETEMPO);
+}
+
+/* this is the structure that gstreamer looks for to register plugins
+ *
+ * exchange the strings 'plugin' and 'Template plugin' with you plugin name and
+ * description
+ */
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR,
+    "scaletempo", "Scale audio tempo in sync with playback rate",
+    plugin_init, VERSION, "LGPL", "GStreamer",
+    "http://gstreamer.freedesktop.org/")