Add audioiirfilter and audiofirfilter elements which allow generic IIR/FIR filters to be implemented by providing the...

Original commit message from CVS:
* configure.ac:
* gst/audiofx/Makefile.am:
* gst/audiofx/audiofirfilter.c: (gst_audio_fir_filter_base_init),
(gst_audio_fir_filter_class_init),
(gst_audio_fir_filter_update_kernel), (gst_audio_fir_filter_init),
(gst_audio_fir_filter_setup), (gst_audio_fir_filter_finalize),
(gst_audio_fir_filter_set_property),
(gst_audio_fir_filter_get_property):
* gst/audiofx/audiofirfilter.h:
* gst/audiofx/audiofx.c: (plugin_init):
* gst/audiofx/audioiirfilter.c: (gst_audio_iir_filter_base_init),
(gst_audio_iir_filter_class_init),
(gst_audio_iir_filter_update_coefficients),
(gst_audio_iir_filter_init), (gst_audio_iir_filter_setup),
(gst_audio_iir_filter_finalize),
(gst_audio_iir_filter_set_property),
(gst_audio_iir_filter_get_property):
* gst/audiofx/audioiirfilter.h:
Add audioiirfilter and audiofirfilter elements which allow
generic IIR/FIR filters to be implemented by providing the
filter coefficients. Fixes bug #567577.
* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-good-plugins-docs.sgml:
* docs/plugins/gst-plugins-good-plugins-sections.txt:
* docs/plugins/gst-plugins-good-plugins.args:
* docs/plugins/gst-plugins-good-plugins.hierarchy:
* docs/plugins/gst-plugins-good-plugins.signals:
* docs/plugins/inspect/plugin-alaw.xml:
* docs/plugins/inspect/plugin-audiofx.xml:
* docs/plugins/inspect/plugin-avi.xml:
* docs/plugins/inspect/plugin-flac.xml:
* docs/plugins/inspect/plugin-mulaw.xml:
* docs/plugins/inspect/plugin-video4linux2.xml:
* docs/plugins/inspect/plugin-wavparse.xml:
Add documentation for the audioiirfilter and audiofirfilter
elements.
* tests/check/Makefile.am:
* tests/check/elements/audiofirfilter.c: (on_message),
(on_rate_changed), (on_handoff), (GST_START_TEST),
(audiofirfilter_suite):
* tests/check/elements/audioiirfilter.c: (on_message),
(on_rate_changed), (on_handoff), (GST_START_TEST),
(audioiirfilter_suite):
* tests/examples/Makefile.am:
* tests/examples/audiofx/Makefile.am:
* tests/examples/audiofx/firfilter-example.c: (on_message),
(on_rate_changed), (main):
* tests/examples/audiofx/iirfilter-example.c: (on_message),
(on_rate_changed), (main):
Add unit tests and example applications for the two filter
elements.

6 files changed, 719 insertions, 2 deletions

diff --git a/gst/audiofx/Makefile.am b/gst/audiofx/Makefile.am
index d93d3e9a..0ba4f1f3 100644
--- a/gst/audiofx/Makefile.am
+++ b/gst/audiofx/Makefile.am
@@ -12,9 +12,11 @@ libgstaudiofx_la_SOURCES = audiofx.c\
 	audiofxbaseiirfilter.c \
 	audiocheblimit.c \
 	audiochebband.c \
+	audioiirfilter.c \
 	audiofxbasefirfilter.c \
 	audiowsincband.c \
-	audiowsinclimit.c
+	audiowsinclimit.c \
+	audiofirfilter.c
 
 # flags used to compile this plugin
 libgstaudiofx_la_CFLAGS = $(GST_CFLAGS) \
@@ -39,8 +41,10 @@ noinst_HEADERS = audiopanorama.h \
 	audiofxbaseiirfilter.h \
 	audiocheblimit.h \
 	audiochebband.h \
+	audioiirfilter.h \
 	audiofxbasefirfilter.h \
 	audiowsincband.h \
         audiowsinclimit.h \
+	audiofirfilter.h \
 	math_compat.h
 
diff --git a/gst/audiofx/audiofirfilter.c b/gst/audiofx/audiofirfilter.c
new file mode 100644
index 00000000..3ee4d832
--- /dev/null
+++ b/gst/audiofx/audiofirfilter.c
@@ -0,0 +1,273 @@
+/* 
+ * GStreamer
+ * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * 
+ */
+
+/**
+ * SECTION:element-audiofirfilter
+ * @short_description: Generic audio FIR filter
+ *
+ * <refsect2>
+ * <para>
+ * audiofirfilter implements a generic audio <ulink url="http://en.wikipedia.org/wiki/Finite_impulse_response">FIR filter</ulink>. Before usage the
+ * "kernel" property has to be set to the filter kernel that should be
+ * used and the "latency" property has to be set to the latency (in samples)
+ * that is introduced by the filter kernel. Setting a latency of n samples
+ * will lead to the first n samples being dropped from the output and
+ * n samples added to the end.
+ * </para>
+ * <para>
+ * The filter kernel describes the impulse response of the filter. To
+ * calculate the frequency response of the filter you have to calculate
+ * the Fourier Transform of the impulse response.
+ * </para>
+ * <para>
+ * To change the filter kernel whenever the sampling rate changes the
+ * "rate-changed" signal can be used. This should be done for most
+ * FIR filters as they're depending on the sampling rate.
+ * </para>
+ * <title>Example application</title>
+ * <para>
+ * <include xmlns="http://www.w3.org/2003/XInclude" href="element-firfilter-example.xml" />
+ * </para>
+ * </refsect2>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+#include <math.h>
+#include <gst/gst.h>
+#include <gst/audio/gstaudiofilter.h>
+#include <gst/controller/gstcontroller.h>
+
+#include "audiofirfilter.h"
+
+#define GST_CAT_DEFAULT gst_audio_fir_filter_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+enum
+{
+  SIGNAL_RATE_CHANGED,
+  LAST_SIGNAL
+};
+
+enum
+{
+  PROP_0,
+  PROP_KERNEL,
+  PROP_LATENCY
+};
+
+static guint gst_audio_fir_filter_signals[LAST_SIGNAL] = { 0, };
+
+#define DEBUG_INIT(bla) \
+  GST_DEBUG_CATEGORY_INIT (gst_audio_fir_filter_debug, "audiofirfilter", 0, \
+      "Generic audio FIR filter plugin");
+
+GST_BOILERPLATE_FULL (GstAudioFIRFilter, gst_audio_fir_filter, GstAudioFilter,
+    GST_TYPE_AUDIO_FX_BASE_FIR_FILTER, DEBUG_INIT);
+
+static void gst_audio_fir_filter_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_audio_fir_filter_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_audio_fir_filter_finalize (GObject * object);
+
+static gboolean gst_audio_fir_filter_setup (GstAudioFilter * base,
+    GstRingBufferSpec * format);
+
+/* Element class */
+static void
+gst_audio_fir_filter_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details_simple (element_class,
+      "Audio FIR filter", "Filter/Effect/Audio",
+      "Generic audio FIR filter with custom filter kernel",
+      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
+}
+
+static void
+gst_audio_fir_filter_class_init (GstAudioFIRFilterClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
+
+  gobject_class->set_property = gst_audio_fir_filter_set_property;
+  gobject_class->get_property = gst_audio_fir_filter_get_property;
+  gobject_class->finalize = gst_audio_fir_filter_finalize;
+
+  g_object_class_install_property (gobject_class, PROP_KERNEL,
+      g_param_spec_value_array ("kernel", "Filter Kernel",
+          "Filter kernel for the FIR filter",
+          g_param_spec_double ("Element", "Filter Kernel Element",
+              "Element of the filter kernel", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
+              G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_LATENCY,
+      g_param_spec_uint64 ("latency", "Latecy",
+          "Filter latency in samples",
+          0, G_MAXUINT64, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_fir_filter_setup);
+
+  /**
+   * GstAudioFIRFilter::rate-changed:
+   * @filter: the filter on which the signal is emitted
+   * @rate: the new sampling rate
+   *
+   * Will be emitted when the sampling rate changes. The callbacks
+   * will be called from the streaming thread and processing will
+   * stop until the event is handled.
+   */
+  gst_audio_fir_filter_signals[SIGNAL_RATE_CHANGED] =
+      g_signal_new ("rate-changed", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAudioFIRFilterClass, rate_changed),
+      NULL, NULL, gst_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
+}
+
+static void
+gst_audio_fir_filter_update_kernel (GstAudioFIRFilter * self, GValueArray * va)
+{
+  gdouble *kernel;
+  guint i;
+
+  gst_audio_fx_base_fir_filter_push_residue (GST_AUDIO_FX_BASE_FIR_FILTER
+      (self));
+
+  if (va) {
+    if (self->kernel)
+      g_value_array_free (self->kernel);
+
+    self->kernel = va;
+  }
+
+  kernel = g_new (gdouble, self->kernel->n_values);
+
+  for (i = 0; i < self->kernel->n_values; i++) {
+    GValue *v = g_value_array_get_nth (self->kernel, i);
+    kernel[i] = g_value_get_double (v);
+  }
+
+  gst_audio_fx_base_fir_filter_set_kernel (GST_AUDIO_FX_BASE_FIR_FILTER (self),
+      kernel, self->kernel->n_values, self->latency);
+}
+
+static void
+gst_audio_fir_filter_init (GstAudioFIRFilter * self,
+    GstAudioFIRFilterClass * g_class)
+{
+  GValue v = { 0, };
+  GValueArray *va;
+
+  self->latency = 0;
+  va = g_value_array_new (1);
+
+  g_value_init (&v, G_TYPE_DOUBLE);
+  g_value_set_double (&v, 1.0);
+  g_value_array_append (va, &v);
+  g_value_unset (&v);
+  gst_audio_fir_filter_update_kernel (self, va);
+
+  self->lock = g_mutex_new ();
+}
+
+/* GstAudioFilter vmethod implementations */
+
+/* get notified of caps and plug in the correct process function */
+static gboolean
+gst_audio_fir_filter_setup (GstAudioFilter * base, GstRingBufferSpec * format)
+{
+  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (base);
+
+  if (self->rate != format->rate) {
+    g_signal_emit (G_OBJECT (self),
+        gst_audio_fir_filter_signals[SIGNAL_RATE_CHANGED], 0, format->rate);
+    self->rate = format->rate;
+  }
+
+  return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
+}
+
+static void
+gst_audio_fir_filter_finalize (GObject * object)
+{
+  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);
+
+  g_mutex_free (self->lock);
+  self->lock = NULL;
+
+  if (self->kernel)
+    g_value_array_free (self->kernel);
+  self->kernel = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_audio_fir_filter_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);
+
+  g_return_if_fail (GST_IS_AUDIO_FIR_FILTER (self));
+
+  switch (prop_id) {
+    case PROP_KERNEL:
+      g_mutex_lock (self->lock);
+      gst_audio_fx_base_fir_filter_push_residue (GST_AUDIO_FX_BASE_FIR_FILTER
+          (self));
+
+      gst_audio_fir_filter_update_kernel (self, g_value_dup_boxed (value));
+      g_mutex_unlock (self->lock);
+      break;
+    case PROP_LATENCY:
+      g_mutex_lock (self->lock);
+      self->latency = g_value_get_uint64 (value);
+      gst_audio_fir_filter_update_kernel (self, NULL);
+      g_mutex_unlock (self->lock);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_audio_fir_filter_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);
+
+  switch (prop_id) {
+    case PROP_KERNEL:
+      g_value_set_boxed (value, self->kernel);
+      break;
+    case PROP_LATENCY:
+      g_value_set_uint64 (value, self->latency);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
diff --git a/gst/audiofx/audiofirfilter.h b/gst/audiofx/audiofirfilter.h
new file mode 100644
index 00000000..d1d896c0
--- /dev/null
+++ b/gst/audiofx/audiofirfilter.h
@@ -0,0 +1,72 @@
+/* 
+ * GStreamer
+ * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * 
+ */
+
+#ifndef __GST_AUDIO_FIR_FILTER_H__
+#define __GST_AUDIO_FIR_FILTER_H__
+
+#include <gst/gst.h>
+#include <gst/audio/gstaudiofilter.h>
+
+#include "audiofxbasefirfilter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_AUDIO_FIR_FILTER \
+  (gst_audio_fir_filter_get_type())
+#define GST_AUDIO_FIR_FILTER(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AUDIO_FIR_FILTER,GstAudioFIRFilter))
+#define GST_AUDIO_FIR_FILTER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AUDIO_FIR_FILTER,GstAudioFIRFilterClass))
+#define GST_IS_AUDIO_FIR_FILTER(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AUDIO_FIR_FILTER))
+#define GST_IS_AUDIO_FIR_FILTER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AUDIO_FIR_FILTER))
+
+typedef struct _GstAudioFIRFilter GstAudioFIRFilter;
+typedef struct _GstAudioFIRFilterClass GstAudioFIRFilterClass;
+
+/**
+ * GstAudioFIRFilter:
+ *
+ * Opaque data structure.
+ */
+struct _GstAudioFIRFilter {
+  GstAudioFXBaseFIRFilter parent;
+
+  GValueArray *kernel;
+  guint64 latency;
+
+  /* < private > */
+  GMutex *lock;
+  gint rate;
+};
+
+struct _GstAudioFIRFilterClass {
+  GstAudioFXBaseFIRFilterClass parent;
+
+  void (*rate_changed) (GstElement * element, gint rate);
+};
+
+GType gst_audio_fir_filter_get_type (void);
+
+G_END_DECLS
+
+#endif /* __GST_AUDIO_FIR_FILTER_H__ */
diff --git a/gst/audiofx/audiofx.c b/gst/audiofx/audiofx.c
index 43d1b0cc..62b70761 100644
--- a/gst/audiofx/audiofx.c
+++ b/gst/audiofx/audiofx.c
@@ -32,8 +32,10 @@
 #include "audiodynamic.h"
 #include "audiocheblimit.h"
 #include "audiochebband.h"
+#include "audioiirfilter.h"
 #include "audiowsincband.h"
 #include "audiowsinclimit.h"
+#include "audiofirfilter.h"
 
 /* entry point to initialize the plug-in
  * initialize the plug-in itself
@@ -60,10 +62,14 @@ plugin_init (GstPlugin * plugin)
           GST_TYPE_AUDIO_CHEB_LIMIT) &&
       gst_element_register (plugin, "audiochebband", GST_RANK_NONE,
           GST_TYPE_AUDIO_CHEB_BAND) &&
+      gst_element_register (plugin, "audioiirfilter", GST_RANK_NONE,
+          GST_TYPE_AUDIO_IIR_FILTER) &&
       gst_element_register (plugin, "audiowsinclimit", GST_RANK_NONE,
           GST_TYPE_AUDIO_WSINC_LIMIT) &&
       gst_element_register (plugin, "audiowsincband", GST_RANK_NONE,
-          GST_TYPE_AUDIO_WSINC_BAND));
+          GST_TYPE_AUDIO_WSINC_BAND) &&
+      gst_element_register (plugin, "audiofirfilter", GST_RANK_NONE,
+          GST_TYPE_AUDIO_FIR_FILTER));
 }
 
 GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
diff --git a/gst/audiofx/audioiirfilter.c b/gst/audiofx/audioiirfilter.c
new file mode 100644
index 00000000..76112c6f
--- /dev/null
+++ b/gst/audiofx/audioiirfilter.c
@@ -0,0 +1,291 @@
+/* 
+ * GStreamer
+ * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * 
+ */
+
+/**
+ * SECTION:element-audioiirfilter
+ * @short_description: Generic audio IIR filter
+ *
+ * <refsect2>
+ * <para>
+ * audioiirfilter implements a generic audio <ulink url="http://en.wikipedia.org/wiki/Infinite_impulse_response">IIR filter</ulink>. Before usage the
+ * "a" and "b" properties have to be set to the filter coefficients that
+ * should be used.
+ * </para>
+ * <para>
+ * The filter coefficients describe the numerator and denominator of the
+ * transfer function.
+ * </para>
+ * <para>
+ * To change the filter coefficients whenever the sampling rate changes the
+ * "rate-changed" signal can be used. This should be done for most
+ * IIR filters as they're depending on the sampling rate.
+ * </para>
+ * <title>Example application</title>
+ * <para>
+ * <include xmlns="http://www.w3.org/2003/XInclude" href="element-iirfilter-example.xml" />
+ * </para>
+ * </refsect2>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+#include <math.h>
+#include <gst/gst.h>
+#include <gst/audio/gstaudiofilter.h>
+#include <gst/controller/gstcontroller.h>
+
+#include "audioiirfilter.h"
+
+#define GST_CAT_DEFAULT gst_audio_iir_filter_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+enum
+{
+  SIGNAL_RATE_CHANGED,
+  LAST_SIGNAL
+};
+
+enum
+{
+  PROP_0,
+  PROP_A,
+  PROP_B
+};
+
+static guint gst_audio_iir_filter_signals[LAST_SIGNAL] = { 0, };
+
+#define DEBUG_INIT(bla) \
+  GST_DEBUG_CATEGORY_INIT (gst_audio_iir_filter_debug, "audioiirfilter", 0, \
+      "Generic audio IIR filter plugin");
+
+GST_BOILERPLATE_FULL (GstAudioIIRFilter, gst_audio_iir_filter, GstAudioFilter,
+    GST_TYPE_AUDIO_FX_BASE_IIR_FILTER, DEBUG_INIT);
+
+static void gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_audio_iir_filter_finalize (GObject * object);
+
+static gboolean gst_audio_iir_filter_setup (GstAudioFilter * base,
+    GstRingBufferSpec * format);
+
+/* Element class */
+static void
+gst_audio_iir_filter_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details_simple (element_class,
+      "Audio IIR filter", "Filter/Effect/Audio",
+      "Generic audio IIR filter with custom filter kernel",
+      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
+}
+
+static void
+gst_audio_iir_filter_class_init (GstAudioIIRFilterClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
+
+  gobject_class->set_property = gst_audio_iir_filter_set_property;
+  gobject_class->get_property = gst_audio_iir_filter_get_property;
+  gobject_class->finalize = gst_audio_iir_filter_finalize;
+
+  g_object_class_install_property (gobject_class, PROP_A,
+      g_param_spec_value_array ("a", "A",
+          "Filter coefficients (numerator of transfer function)",
+          g_param_spec_double ("Coefficient", "Filter Coefficient",
+              "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
+              G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_B,
+      g_param_spec_value_array ("b", "B",
+          "Filter coefficients (denominator of transfer function)",
+          g_param_spec_double ("Coefficient", "Filter Coefficient",
+              "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
+              G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_iir_filter_setup);
+
+  /**
+   * GstAudioIIRFilter::rate-changed:
+   * @filter: the filter on which the signal is emitted
+   * @rate: the new sampling rate
+   *
+   * Will be emitted when the sampling rate changes. The callbacks
+   * will be called from the streaming thread and processing will
+   * stop until the event is handled.
+   */
+  gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED] =
+      g_signal_new ("rate-changed", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAudioIIRFilterClass, rate_changed),
+      NULL, NULL, gst_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
+}
+
+static void
+gst_audio_iir_filter_update_coefficients (GstAudioIIRFilter * self,
+    GValueArray * va, GValueArray * vb)
+{
+  gdouble *a = NULL, *b = NULL;
+  guint i;
+
+  if (va) {
+    if (self->a)
+      g_value_array_free (self->a);
+
+    self->a = va;
+  }
+  if (vb) {
+    if (self->b)
+      g_value_array_free (self->b);
+
+    self->b = vb;
+  }
+
+  if (self->a && self->a->n_values > 0)
+    a = g_new (gdouble, self->a->n_values);
+  if (self->b && self->b->n_values > 0)
+    b = g_new (gdouble, self->b->n_values);
+
+  if (self->a) {
+    for (i = 0; i < self->a->n_values; i++) {
+      GValue *v = g_value_array_get_nth (self->a, i);
+      a[i] = g_value_get_double (v);
+    }
+  }
+
+  if (self->b) {
+    for (i = 0; i < self->b->n_values; i++) {
+      GValue *v = g_value_array_get_nth (self->b, i);
+      b[i] = g_value_get_double (v);
+    }
+  }
+
+  gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
+      (self), a, (self->a) ? self->a->n_values : 0, b,
+      (self->b) ? self->b->n_values : 0);
+}
+
+static void
+gst_audio_iir_filter_init (GstAudioIIRFilter * self,
+    GstAudioIIRFilterClass * g_class)
+{
+  GValue v = { 0, };
+  GValueArray *a, *b;
+
+  a = g_value_array_new (1);
+
+  g_value_init (&v, G_TYPE_DOUBLE);
+  g_value_set_double (&v, 1.0);
+  g_value_array_append (a, &v);
+  g_value_unset (&v);
+
+  b = NULL;
+  gst_audio_iir_filter_update_coefficients (self, a, b);
+
+  self->lock = g_mutex_new ();
+}
+
+/* GstAudioFilter vmethod implementations */
+
+/* get notified of caps and plug in the correct process function */
+static gboolean
+gst_audio_iir_filter_setup (GstAudioFilter * base, GstRingBufferSpec * format)
+{
+  GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (base);
+
+  if (self->rate != format->rate) {
+    g_signal_emit (G_OBJECT (self),
+        gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED], 0, format->rate);
+    self->rate = format->rate;
+  }
+
+  return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
+}
+
+static void
+gst_audio_iir_filter_finalize (GObject * object)
+{
+  GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
+
+  g_mutex_free (self->lock);
+  self->lock = NULL;
+
+  if (self->a)
+    g_value_array_free (self->a);
+  self->a = NULL;
+  if (self->b)
+    g_value_array_free (self->b);
+  self->b = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
+
+  g_return_if_fail (GST_IS_AUDIO_IIR_FILTER (self));
+
+  switch (prop_id) {
+    case PROP_A:
+      g_mutex_lock (self->lock);
+      gst_audio_iir_filter_update_coefficients (self, g_value_dup_boxed (value),
+          NULL);
+      g_mutex_unlock (self->lock);
+      break;
+    case PROP_B:
+      g_mutex_lock (self->lock);
+      gst_audio_iir_filter_update_coefficients (self, NULL,
+          g_value_dup_boxed (value));
+      g_mutex_unlock (self->lock);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
+
+  switch (prop_id) {
+    case PROP_A:
+      g_value_set_boxed (value, self->a);
+      break;
+    case PROP_B:
+      g_value_set_boxed (value, self->b);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
diff --git a/gst/audiofx/audioiirfilter.h b/gst/audiofx/audioiirfilter.h
new file mode 100644
index 00000000..607edf27
--- /dev/null
+++ b/gst/audiofx/audioiirfilter.h
@@ -0,0 +1,71 @@
+/* 
+ * GStreamer
+ * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * 
+ */
+
+#ifndef __GST_AUDIO_IIR_FILTER_H__
+#define __GST_AUDIO_IIR_FILTER_H__
+
+#include <gst/gst.h>
+#include <gst/audio/gstaudiofilter.h>
+
+#include "audiofxbaseiirfilter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_AUDIO_IIR_FILTER \
+  (gst_audio_iir_filter_get_type())
+#define GST_AUDIO_IIR_FILTER(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AUDIO_IIR_FILTER,GstAudioIIRFilter))
+#define GST_AUDIO_IIR_FILTER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AUDIO_IIR_FILTER,GstAudioIIRFilterClass))
+#define GST_IS_AUDIO_IIR_FILTER(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AUDIO_IIR_FILTER))
+#define GST_IS_AUDIO_IIR_FILTER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AUDIO_IIR_FILTER))
+
+typedef struct _GstAudioIIRFilter GstAudioIIRFilter;
+typedef struct _GstAudioIIRFilterClass GstAudioIIRFilterClass;
+
+/**
+ * GstAudioIIRFilter:
+ *
+ * Opaque data structure.
+ */
+struct _GstAudioIIRFilter {
+  GstAudioFXBaseIIRFilter parent;
+
+  GValueArray *a, *b;
+
+  /* < private > */
+  GMutex *lock;
+  gint rate;
+};
+
+struct _GstAudioIIRFilterClass {
+  GstAudioFXBaseIIRFilterClass parent;
+
+  void (*rate_changed) (GstElement * element, gint rate);
+};
+
+GType gst_audio_iir_filter_get_type (void);
+
+G_END_DECLS
+
+#endif /* __GST_AUDIO_IIR_FILTER_H__ */