--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_good/gst/audiofx/audiowsinclimit.c	Fri Apr 16 15:15:52 2010 +0300
@@ -0,0 +1,373 @@
+/* -*- c-basic-offset: 2 -*-
+ * 
+ * GStreamer
+ * Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
+ *               2006 Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>
+ *               2007-2009 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.
+ * 
+ * 
+ * this windowed sinc filter is taken from the freely downloadable DSP book,
+ * "The Scientist and Engineer's Guide to Digital Signal Processing",
+ * chapter 16
+ * available at http://www.dspguide.com/
+ *
+ */
+
+/**
+ * SECTION:element-audiowsinclimit
+ *
+ * Attenuates all frequencies above the cutoff frequency (low-pass) or all frequencies below the
+ * cutoff frequency (high-pass). The length parameter controls the rolloff, the window parameter
+ * controls rolloff and stopband attenuation. The Hamming window provides a faster rolloff but a bit
+ * worse stopband attenuation, the other way around for the Blackman window.
+ *
+ * This element has the advantage over the Chebyshev lowpass and highpass filter that it has
+ * a much better rolloff when using a larger kernel size and almost linear phase. The only
+ * disadvantage is the much slower execution time with larger kernels.
+ *
+ * <refsect2>
+ * <title>Example launch line</title>
+ * |[
+ * gst-launch audiotestsrc freq=1500 ! audioconvert ! audiowsinclimit mode=low-pass frequency=1000 length=501 ! audioconvert ! alsasink
+ * gst-launch filesrc location="melo1.ogg" ! oggdemux ! vorbisdec ! audioconvert ! audiowsinclimit mode=high-pass frequency=15000 length=501 ! audioconvert ! alsasink
+ * gst-launch audiotestsrc wave=white-noise ! audioconvert ! audiowsinclimit mode=low-pass frequency=1000 length=10001 window=blackman ! audioconvert ! alsasink
+ * ]|
+ * </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 "audiowsinclimit.h"
+
+#define GST_CAT_DEFAULT gst_audio_wsinclimit_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+enum
+{
+  PROP_0,
+  PROP_LENGTH,
+  PROP_FREQUENCY,
+  PROP_MODE,
+  PROP_WINDOW
+};
+
+enum
+{
+  MODE_LOW_PASS = 0,
+  MODE_HIGH_PASS
+};
+
+#define GST_TYPE_AUDIO_WSINC_LIMIT_MODE (gst_audio_wsinclimit_mode_get_type ())
+static GType
+gst_audio_wsinclimit_mode_get_type (void)
+{
+  static GType gtype = 0;
+
+  if (gtype == 0) {
+    static const GEnumValue values[] = {
+      {MODE_LOW_PASS, "Low pass (default)",
+          "low-pass"},
+      {MODE_HIGH_PASS, "High pass",
+          "high-pass"},
+      {0, NULL, NULL}
+    };
+
+    gtype = g_enum_register_static ("GstAudioWSincLimitMode", values);
+  }
+  return gtype;
+}
+
+enum
+{
+  WINDOW_HAMMING = 0,
+  WINDOW_BLACKMAN
+};
+
+#define GST_TYPE_AUDIO_WSINC_LIMIT_WINDOW (gst_audio_wsinclimit_window_get_type ())
+static GType
+gst_audio_wsinclimit_window_get_type (void)
+{
+  static GType gtype = 0;
+
+  if (gtype == 0) {
+    static const GEnumValue values[] = {
+      {WINDOW_HAMMING, "Hamming window (default)",
+          "hamming"},
+      {WINDOW_BLACKMAN, "Blackman window",
+          "blackman"},
+      {0, NULL, NULL}
+    };
+
+    gtype = g_enum_register_static ("GstAudioWSincLimitWindow", values);
+  }
+  return gtype;
+}
+
+#define DEBUG_INIT(bla) \
+  GST_DEBUG_CATEGORY_INIT (gst_audio_wsinclimit_debug, "audiowsinclimit", 0, \
+      "Low-pass and High-pass Windowed sinc filter plugin");
+
+GST_BOILERPLATE_FULL (GstAudioWSincLimit, gst_audio_wsinclimit, GstAudioFilter,
+    GST_TYPE_AUDIO_FX_BASE_FIR_FILTER, DEBUG_INIT);
+
+static void gst_audio_wsinclimit_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_audio_wsinclimit_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_audio_wsinclimit_finalize (GObject * object);
+
+static gboolean gst_audio_wsinclimit_setup (GstAudioFilter * base,
+    GstRingBufferSpec * format);
+
+/* Element class */
+
+static void
+gst_audio_wsinclimit_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  gst_element_class_set_details_simple (element_class,
+      "Low pass & high pass filter", "Filter/Effect/Audio",
+      "Low pass and high pass windowed sinc filter",
+      "Thomas Vander Stichele <thomas at apestaart dot org>, "
+      "Steven W. Smith, "
+      "Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>, "
+      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
+}
+
+static void
+gst_audio_wsinclimit_class_init (GstAudioWSincLimitClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
+
+  gobject_class->set_property = gst_audio_wsinclimit_set_property;
+  gobject_class->get_property = gst_audio_wsinclimit_get_property;
+  gobject_class->finalize = gst_audio_wsinclimit_finalize;
+
+  /* FIXME: Don't use the complete possible range but restrict the upper boundary
+   * so automatically generated UIs can use a slider */
+  g_object_class_install_property (gobject_class, PROP_FREQUENCY,
+      g_param_spec_float ("cutoff", "Cutoff",
+          "Cut-off Frequency (Hz)", 0.0, 100000.0, 0.0,
+          G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_LENGTH,
+      g_param_spec_int ("length", "Length",
+          "Filter kernel length, will be rounded to the next odd number",
+          3, 50000, 101,
+          G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_MODE,
+      g_param_spec_enum ("mode", "Mode",
+          "Low pass or high pass mode", GST_TYPE_AUDIO_WSINC_LIMIT_MODE,
+          MODE_LOW_PASS,
+          G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_WINDOW,
+      g_param_spec_enum ("window", "Window",
+          "Window function to use", GST_TYPE_AUDIO_WSINC_LIMIT_WINDOW,
+          WINDOW_HAMMING,
+          G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
+
+  filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_wsinclimit_setup);
+}
+
+static void
+gst_audio_wsinclimit_init (GstAudioWSincLimit * self,
+    GstAudioWSincLimitClass * g_class)
+{
+  self->mode = MODE_LOW_PASS;
+  self->window = WINDOW_HAMMING;
+  self->kernel_length = 101;
+  self->cutoff = 0.0;
+
+  self->lock = g_mutex_new ();
+}
+
+static void
+gst_audio_wsinclimit_build_kernel (GstAudioWSincLimit * self)
+{
+  gint i = 0;
+  gdouble sum = 0.0;
+  gint len = 0;
+  gdouble w;
+  gdouble *kernel = NULL;
+
+  len = self->kernel_length;
+
+  if (GST_AUDIO_FILTER (self)->format.rate == 0) {
+    GST_DEBUG ("rate not set yet");
+    return;
+  }
+
+  if (GST_AUDIO_FILTER (self)->format.channels == 0) {
+    GST_DEBUG ("channels not set yet");
+    return;
+  }
+
+  /* Clamp cutoff frequency between 0 and the nyquist frequency */
+  self->cutoff =
+      CLAMP (self->cutoff, 0.0, GST_AUDIO_FILTER (self)->format.rate / 2);
+
+  GST_DEBUG ("gst_audio_wsinclimit_: initializing filter kernel of length %d "
+      "with cutoff %.2lf Hz "
+      "for mode %s",
+      len, self->cutoff,
+      (self->mode == MODE_LOW_PASS) ? "low-pass" : "high-pass");
+
+  /* fill the kernel */
+  w = 2 * M_PI * (self->cutoff / GST_AUDIO_FILTER (self)->format.rate);
+
+  kernel = g_new (gdouble, len);
+
+  for (i = 0; i < len; ++i) {
+    if (i == len / 2)
+      kernel[i] = w;
+    else
+      kernel[i] = sin (w * (i - len / 2)) / (i - len / 2);
+    /* windowing */
+    if (self->window == WINDOW_HAMMING)
+      kernel[i] *= (0.54 - 0.46 * cos (2 * M_PI * i / len));
+    else
+      kernel[i] *= (0.42 - 0.5 * cos (2 * M_PI * i / len) +
+          0.08 * cos (4 * M_PI * i / len));
+  }
+
+  /* normalize for unity gain at DC */
+  for (i = 0; i < len; ++i)
+    sum += kernel[i];
+  for (i = 0; i < len; ++i)
+    kernel[i] /= sum;
+
+  /* convert to highpass if specified */
+  if (self->mode == MODE_HIGH_PASS) {
+    for (i = 0; i < len; ++i)
+      kernel[i] = -kernel[i];
+    kernel[len / 2] += 1.0;
+  }
+
+  gst_audio_fx_base_fir_filter_set_kernel (GST_AUDIO_FX_BASE_FIR_FILTER (self),
+      kernel, self->kernel_length, (len - 1) / 2);
+}
+
+/* GstAudioFilter vmethod implementations */
+
+/* get notified of caps and plug in the correct process function */
+static gboolean
+gst_audio_wsinclimit_setup (GstAudioFilter * base, GstRingBufferSpec * format)
+{
+  GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (base);
+
+  gst_audio_wsinclimit_build_kernel (self);
+
+  return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
+}
+
+static void
+gst_audio_wsinclimit_finalize (GObject * object)
+{
+  GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
+
+  g_mutex_free (self->lock);
+  self->lock = NULL;
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_audio_wsinclimit_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
+
+  g_return_if_fail (GST_IS_AUDIO_WSINC_LIMIT (self));
+
+  switch (prop_id) {
+    case PROP_LENGTH:{
+      gint val;
+
+      g_mutex_lock (self->lock);
+      val = g_value_get_int (value);
+      if (val % 2 == 0)
+        val++;
+
+      if (val != self->kernel_length) {
+        gst_audio_fx_base_fir_filter_push_residue (GST_AUDIO_FX_BASE_FIR_FILTER
+            (self));
+        self->kernel_length = val;
+        gst_audio_wsinclimit_build_kernel (self);
+      }
+      g_mutex_unlock (self->lock);
+      break;
+    }
+    case PROP_FREQUENCY:
+      g_mutex_lock (self->lock);
+      self->cutoff = g_value_get_float (value);
+      gst_audio_wsinclimit_build_kernel (self);
+      g_mutex_unlock (self->lock);
+      break;
+    case PROP_MODE:
+      g_mutex_lock (self->lock);
+      self->mode = g_value_get_enum (value);
+      gst_audio_wsinclimit_build_kernel (self);
+      g_mutex_unlock (self->lock);
+      break;
+    case PROP_WINDOW:
+      g_mutex_lock (self->lock);
+      self->window = g_value_get_enum (value);
+      gst_audio_wsinclimit_build_kernel (self);
+      g_mutex_unlock (self->lock);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_audio_wsinclimit_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
+
+  switch (prop_id) {
+    case PROP_LENGTH:
+      g_value_set_int (value, self->kernel_length);
+      break;
+    case PROP_FREQUENCY:
+      g_value_set_float (value, self->cutoff);
+      break;
+    case PROP_MODE:
+      g_value_set_enum (value, self->mode);
+      break;
+    case PROP_WINDOW:
+      g_value_set_enum (value, self->window);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}