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/* -*- 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, 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/
*
* For the window functions see
* http://en.wikipedia.org/wiki/Window_function
*/
/**
* SECTION:element-audiowsincband
*
* Attenuates all frequencies outside (bandpass) or inside (bandreject) of a frequency
* band. 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 bandpass and bandreject 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-1.0 audiotestsrc freq=1500 ! audioconvert ! audiosincband mode=band-pass lower-frequency=3000 upper-frequency=10000 length=501 window=blackman ! audioconvert ! alsasink
* gst-launch-1.0 filesrc location="melo1.ogg" ! oggdemux ! vorbisdec ! audioconvert ! audiowsincband mode=band-reject lower-frequency=59 upper-frequency=61 length=10001 window=hamming ! audioconvert ! alsasink
* gst-launch-1.0 audiotestsrc wave=white-noise ! audioconvert ! audiowsincband mode=band-pass lower-frequency=1000 upper-frequency=2000 length=31 ! 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 "audiowsincband.h"
#include "gst/glib-compat-private.h"
#define GST_CAT_DEFAULT gst_gst_audio_wsincband_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
enum
{
PROP_0,
PROP_LENGTH,
PROP_LOWER_FREQUENCY,
PROP_UPPER_FREQUENCY,
PROP_MODE,
PROP_WINDOW
};
enum
{
MODE_BAND_PASS = 0,
MODE_BAND_REJECT
};
#define GST_TYPE_AUDIO_WSINC_BAND_MODE (gst_gst_audio_wsincband_mode_get_type ())
static GType
gst_gst_audio_wsincband_mode_get_type (void)
{
static GType gtype = 0;
if (gtype == 0) {
static const GEnumValue values[] = {
{MODE_BAND_PASS, "Band pass (default)",
"band-pass"},
{MODE_BAND_REJECT, "Band reject",
"band-reject"},
{0, NULL, NULL}
};
gtype = g_enum_register_static ("GstAudioWSincBandMode", values);
}
return gtype;
}
enum
{
WINDOW_HAMMING = 0,
WINDOW_BLACKMAN,
WINDOW_GAUSSIAN,
WINDOW_COSINE,
WINDOW_HANN
};
#define GST_TYPE_AUDIO_WSINC_BAND_WINDOW (gst_gst_audio_wsincband_window_get_type ())
static GType
gst_gst_audio_wsincband_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"},
{WINDOW_GAUSSIAN, "Gaussian window",
"gaussian"},
{WINDOW_COSINE, "Cosine window",
"cosine"},
{WINDOW_HANN, "Hann window",
"hann"},
{0, NULL, NULL}
};
gtype = g_enum_register_static ("GstAudioWSincBandWindow", values);
}
return gtype;
}
#define gst_audio_wsincband_parent_class parent_class
G_DEFINE_TYPE (GstAudioWSincBand, gst_audio_wsincband,
GST_TYPE_AUDIO_FX_BASE_FIR_FILTER);
static void gst_audio_wsincband_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_audio_wsincband_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_audio_wsincband_finalize (GObject * object);
static gboolean gst_audio_wsincband_setup (GstAudioFilter * base,
const GstAudioInfo * info);
#define POW2(x) (x)*(x)
static void
gst_audio_wsincband_class_init (GstAudioWSincBandClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
GstElementClass *gstelement_class = (GstElementClass *) klass;
GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
GST_DEBUG_CATEGORY_INIT (gst_gst_audio_wsincband_debug, "audiowsincband", 0,
"Band-pass and Band-reject Windowed sinc filter plugin");
gobject_class->set_property = gst_audio_wsincband_set_property;
gobject_class->get_property = gst_audio_wsincband_get_property;
gobject_class->finalize = gst_audio_wsincband_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_LOWER_FREQUENCY,
g_param_spec_float ("lower-frequency", "Lower Frequency",
"Cut-off lower frequency (Hz)", 0.0, 100000.0, 0,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_UPPER_FREQUENCY,
g_param_spec_float ("upper-frequency", "Upper Frequency",
"Cut-off upper frequency (Hz)", 0.0, 100000.0, 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,
256000, 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",
"Band pass or band reject mode", GST_TYPE_AUDIO_WSINC_BAND_MODE,
MODE_BAND_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_BAND_WINDOW,
WINDOW_HAMMING,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
gst_element_class_set_static_metadata (gstelement_class,
"Band pass & band reject filter", "Filter/Effect/Audio",
"Band pass and band reject 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>");
filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_wsincband_setup);
}
static void
gst_audio_wsincband_init (GstAudioWSincBand * self)
{
self->kernel_length = 101;
self->lower_frequency = 0.0;
self->upper_frequency = 0.0;
self->mode = MODE_BAND_PASS;
self->window = WINDOW_HAMMING;
g_mutex_init (&self->lock);
}
static void
gst_audio_wsincband_build_kernel (GstAudioWSincBand * self,
const GstAudioInfo * info)
{
gint i = 0;
gdouble sum = 0.0;
gint len = 0;
gdouble *kernel_lp, *kernel_hp;
gdouble w;
gdouble *kernel;
gint rate, channels;
len = self->kernel_length;
if (info) {
rate = GST_AUDIO_INFO_RATE (info);
channels = GST_AUDIO_INFO_CHANNELS (info);
} else {
rate = GST_AUDIO_FILTER_RATE (self);
channels = GST_AUDIO_FILTER_CHANNELS (self);
}
if (rate == 0) {
GST_DEBUG ("rate not set yet");
return;
}
if (channels == 0) {
GST_DEBUG ("channels not set yet");
return;
}
/* Clamp frequencies */
self->lower_frequency = CLAMP (self->lower_frequency, 0.0, rate / 2);
self->upper_frequency = CLAMP (self->upper_frequency, 0.0, rate / 2);
if (self->lower_frequency > self->upper_frequency) {
gint tmp = self->lower_frequency;
self->lower_frequency = self->upper_frequency;
self->upper_frequency = tmp;
}
GST_DEBUG ("gst_audio_wsincband: initializing filter kernel of length %d "
"with lower frequency %.2lf Hz "
", upper frequency %.2lf Hz for mode %s",
len, self->lower_frequency, self->upper_frequency,
(self->mode == MODE_BAND_PASS) ? "band-pass" : "band-reject");
/* fill the lp kernel */
w = 2 * G_PI * (self->lower_frequency / rate);
kernel_lp = g_new (gdouble, len);
for (i = 0; i < len; ++i) {
if (i == (len - 1) / 2.0)
kernel_lp[i] = w;
else
kernel_lp[i] = sin (w * (i - (len - 1) / 2.0)) / (i - (len - 1) / 2.0);
/* windowing */
switch (self->window) {
case WINDOW_HAMMING:
kernel_lp[i] *= (0.54 - 0.46 * cos (2 * G_PI * i / (len - 1)));
break;
case WINDOW_BLACKMAN:
kernel_lp[i] *= (0.42 - 0.5 * cos (2 * G_PI * i / (len - 1)) +
0.08 * cos (4 * G_PI * i / (len - 1)));
break;
case WINDOW_GAUSSIAN:
kernel_lp[i] *= exp (-0.5 * POW2 (3.0 / len * (2 * i - (len - 1))));
break;
case WINDOW_COSINE:
kernel_lp[i] *= cos (G_PI * i / (len - 1) - G_PI / 2);
break;
case WINDOW_HANN:
kernel_lp[i] *= 0.5 * (1 - cos (2 * G_PI * i / (len - 1)));
break;
}
}
/* normalize for unity gain at DC */
sum = 0.0;
for (i = 0; i < len; ++i)
sum += kernel_lp[i];
for (i = 0; i < len; ++i)
kernel_lp[i] /= sum;
/* fill the hp kernel */
w = 2 * G_PI * (self->upper_frequency / rate);
kernel_hp = g_new (gdouble, len);
for (i = 0; i < len; ++i) {
if (i == (len - 1) / 2.0)
kernel_hp[i] = w;
else
kernel_hp[i] = sin (w * (i - (len - 1) / 2.0)) / (i - (len - 1) / 2.0);
/* Windowing */
switch (self->window) {
case WINDOW_HAMMING:
kernel_hp[i] *= (0.54 - 0.46 * cos (2 * G_PI * i / (len - 1)));
break;
case WINDOW_BLACKMAN:
kernel_hp[i] *= (0.42 - 0.5 * cos (2 * G_PI * i / (len - 1)) +
0.08 * cos (4 * G_PI * i / (len - 1)));
break;
case WINDOW_GAUSSIAN:
kernel_hp[i] *= exp (-0.5 * POW2 (3.0 / len * (2 * i - (len - 1))));
break;
case WINDOW_COSINE:
kernel_hp[i] *= cos (G_PI * i / (len - 1) - G_PI / 2);
break;
case WINDOW_HANN:
kernel_hp[i] *= 0.5 * (1 - cos (2 * G_PI * i / (len - 1)));
break;
}
}
/* normalize for unity gain at DC */
sum = 0.0;
for (i = 0; i < len; ++i)
sum += kernel_hp[i];
for (i = 0; i < len; ++i)
kernel_hp[i] /= sum;
/* do spectral inversion to go from lowpass to highpass */
for (i = 0; i < len; ++i)
kernel_hp[i] = -kernel_hp[i];
if (len % 2 == 1) {
kernel_hp[(len - 1) / 2] += 1.0;
} else {
kernel_hp[len / 2 - 1] += 0.5;
kernel_hp[len / 2] += 0.5;
}
/* combine the two kernels */
kernel = g_new (gdouble, len);
for (i = 0; i < len; ++i)
kernel[i] = kernel_lp[i] + kernel_hp[i];
/* free the helper kernels */
g_free (kernel_lp);
g_free (kernel_hp);
/* do spectral inversion to go from bandreject to bandpass
* if specified */
if (self->mode == MODE_BAND_PASS) {
for (i = 0; i < len; ++i)
kernel[i] = -kernel[i];
kernel[len / 2] += 1;
}
gst_audio_fx_base_fir_filter_set_kernel (GST_AUDIO_FX_BASE_FIR_FILTER (self),
kernel, self->kernel_length, (len - 1) / 2, info);
}
/* GstAudioFilter vmethod implementations */
/* get notified of caps and plug in the correct process function */
static gboolean
gst_audio_wsincband_setup (GstAudioFilter * base, const GstAudioInfo * info)
{
GstAudioWSincBand *self = GST_AUDIO_WSINC_BAND (base);
gst_audio_wsincband_build_kernel (self, info);
return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, info);
}
static void
gst_audio_wsincband_finalize (GObject * object)
{
GstAudioWSincBand *self = GST_AUDIO_WSINC_BAND (object);
g_mutex_clear (&self->lock);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_audio_wsincband_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstAudioWSincBand *self = GST_AUDIO_WSINC_BAND (object);
g_return_if_fail (GST_IS_AUDIO_WSINC_BAND (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_wsincband_build_kernel (self, NULL);
}
g_mutex_unlock (&self->lock);
break;
}
case PROP_LOWER_FREQUENCY:
g_mutex_lock (&self->lock);
self->lower_frequency = g_value_get_float (value);
gst_audio_wsincband_build_kernel (self, NULL);
g_mutex_unlock (&self->lock);
break;
case PROP_UPPER_FREQUENCY:
g_mutex_lock (&self->lock);
self->upper_frequency = g_value_get_float (value);
gst_audio_wsincband_build_kernel (self, NULL);
g_mutex_unlock (&self->lock);
break;
case PROP_MODE:
g_mutex_lock (&self->lock);
self->mode = g_value_get_enum (value);
gst_audio_wsincband_build_kernel (self, NULL);
g_mutex_unlock (&self->lock);
break;
case PROP_WINDOW:
g_mutex_lock (&self->lock);
self->window = g_value_get_enum (value);
gst_audio_wsincband_build_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_wsincband_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstAudioWSincBand *self = GST_AUDIO_WSINC_BAND (object);
switch (prop_id) {
case PROP_LENGTH:
g_value_set_int (value, self->kernel_length);
break;
case PROP_LOWER_FREQUENCY:
g_value_set_float (value, self->lower_frequency);
break;
case PROP_UPPER_FREQUENCY:
g_value_set_float (value, self->upper_frequency);
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;
}
}