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gstreamer/gst/audiofx/audiochebband.c
Tim-Philipp Müller 37409d4d65 Don't use deprecated GLib API
2012-01-22 23:32:51 +00:00

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/*
* GStreamer
* Copyright (C) 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.
*/
/*
* Chebyshev type 1 filter design based on
* "The Scientist and Engineer's Guide to DSP", Chapter 20.
* http://www.dspguide.com/
*
* For type 2 and Chebyshev filters in general read
* http://en.wikipedia.org/wiki/Chebyshev_filter
*
* Transformation from lowpass to bandpass/bandreject:
* http://docs.dewresearch.com/DspHelp/html/IDH_LinearSystems_LowpassToBandPassZ.htm
* http://docs.dewresearch.com/DspHelp/html/IDH_LinearSystems_LowpassToBandStopZ.htm
*
*/
/**
* SECTION:element-audiochebband
*
* Attenuates all frequencies outside (bandpass) or inside (bandreject) of a frequency
* band. The number of poles and the ripple parameter control the rolloff.
*
* This element has the advantage over the windowed sinc bandpass and bandreject filter that it is
* much faster and produces almost as good results. It's only disadvantages are the highly
* non-linear phase and the slower rolloff compared to a windowed sinc filter with a large kernel.
*
* For type 1 the ripple parameter specifies how much ripple in dB is allowed in the passband, i.e.
* some frequencies in the passband will be amplified by that value. A higher ripple value will allow
* a faster rolloff.
*
* For type 2 the ripple parameter specifies the stopband attenuation. In the stopband the gain will
* be at most this value. A lower ripple value will allow a faster rolloff.
*
* As a special case, a Chebyshev type 1 filter with no ripple is a Butterworth filter.
*
* <note>
* Be warned that a too large number of poles can produce noise. The most poles are possible with
* a cutoff frequency at a quarter of the sampling rate.
* </note>
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch audiotestsrc freq=1500 ! audioconvert ! audiochebband mode=band-pass lower-frequency=1000 upper-frequenc=6000 poles=4 ! audioconvert ! alsasink
* gst-launch filesrc location="melo1.ogg" ! oggdemux ! vorbisdec ! audioconvert ! audiochebband mode=band-reject lower-frequency=1000 upper-frequency=4000 ripple=0.2 ! audioconvert ! alsasink
* gst-launch audiotestsrc wave=white-noise ! audioconvert ! audiochebband mode=band-pass lower-frequency=1000 upper-frequency=4000 type=2 ! audioconvert ! alsasink
* ]|
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <gst/gst.h>
#include <gst/base/gstbasetransform.h>
#include <gst/audio/audio.h>
#include <gst/audio/gstaudiofilter.h>
#include <math.h>
#include "math_compat.h"
#include "audiochebband.h"
#include "gst/glib-compat-private.h"
#define GST_CAT_DEFAULT gst_audio_cheb_band_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
enum
{
PROP_0,
PROP_MODE,
PROP_TYPE,
PROP_LOWER_FREQUENCY,
PROP_UPPER_FREQUENCY,
PROP_RIPPLE,
PROP_POLES
};
#define gst_audio_cheb_band_parent_class parent_class
G_DEFINE_TYPE (GstAudioChebBand, gst_audio_cheb_band,
GST_TYPE_AUDIO_FX_BASE_IIR_FILTER);
static void gst_audio_cheb_band_set_property (GObject * object,
guint prop_id, const GValue * value, GParamSpec * pspec);
static void gst_audio_cheb_band_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec);
static void gst_audio_cheb_band_finalize (GObject * object);
static gboolean gst_audio_cheb_band_setup (GstAudioFilter * filter,
const GstAudioInfo * info);
enum
{
MODE_BAND_PASS = 0,
MODE_BAND_REJECT
};
#define GST_TYPE_AUDIO_CHEBYSHEV_FREQ_BAND_MODE (gst_audio_cheb_band_mode_get_type ())
static GType
gst_audio_cheb_band_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 ("GstAudioChebBandMode", values);
}
return gtype;
}
/* GObject vmethod implementations */
static void
gst_audio_cheb_band_class_init (GstAudioChebBandClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
GstElementClass *gstelement_class = (GstElementClass *) klass;
GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
GST_DEBUG_CATEGORY_INIT (gst_audio_cheb_band_debug, "audiochebband", 0,
"audiochebband element");
gobject_class->set_property = gst_audio_cheb_band_set_property;
gobject_class->get_property = gst_audio_cheb_band_get_property;
gobject_class->finalize = gst_audio_cheb_band_finalize;
g_object_class_install_property (gobject_class, PROP_MODE,
g_param_spec_enum ("mode", "Mode",
"Low pass or high pass mode", GST_TYPE_AUDIO_CHEBYSHEV_FREQ_BAND_MODE,
MODE_BAND_PASS,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_TYPE,
g_param_spec_int ("type", "Type", "Type of the chebychev filter", 1, 2, 1,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
/* FIXME: Don't use the complete possible range but restrict the upper boundary
* so automatically generated UIs can use a slider without */
g_object_class_install_property (gobject_class, PROP_LOWER_FREQUENCY,
g_param_spec_float ("lower-frequency", "Lower frequency",
"Start frequency of the band (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_UPPER_FREQUENCY,
g_param_spec_float ("upper-frequency", "Upper frequency",
"Stop frequency of the band (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_RIPPLE,
g_param_spec_float ("ripple", "Ripple", "Amount of ripple (dB)", 0.0,
200.0, 0.25,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
/* FIXME: What to do about this upper boundary? With a frequencies near
* rate/4 32 poles are completely possible, with frequencies very low
* or very high 16 poles already produces only noise */
g_object_class_install_property (gobject_class, PROP_POLES,
g_param_spec_int ("poles", "Poles",
"Number of poles to use, will be rounded up to the next multiply of four",
4, 32, 4,
G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
gst_element_class_set_details_simple (gstelement_class,
"Band pass & band reject filter", "Filter/Effect/Audio",
"Chebyshev band pass and band reject filter",
"Sebastian Dröge <sebastian.droege@collabora.co.uk>");
filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_cheb_band_setup);
}
static void
gst_audio_cheb_band_init (GstAudioChebBand * filter)
{
filter->lower_frequency = filter->upper_frequency = 0.0;
filter->mode = MODE_BAND_PASS;
filter->type = 1;
filter->poles = 4;
filter->ripple = 0.25;
g_mutex_init (&filter->lock);
}
static void
generate_biquad_coefficients (GstAudioChebBand * filter,
gint p, gdouble * b0, gdouble * b1, gdouble * b2, gdouble * b3,
gdouble * b4, gdouble * a1, gdouble * a2, gdouble * a3, gdouble * a4)
{
gint np = filter->poles / 2;
gdouble ripple = filter->ripple;
gint rate = GST_AUDIO_FILTER_RATE (filter);
/* pole location in s-plane */
gdouble rp, ip;
/* zero location in s-plane */
gdouble iz = 0.0;
/* transfer function coefficients for the z-plane */
gdouble x0, x1, x2, y1, y2;
gint type = filter->type;
/* Calculate pole location for lowpass at frequency 1 */
{
gdouble angle = (G_PI / 2.0) * (2.0 * p - 1) / np;
rp = -sin (angle);
ip = cos (angle);
}
/* If we allow ripple, move the pole from the unit
* circle to an ellipse and keep cutoff at frequency 1 */
if (ripple > 0 && type == 1) {
gdouble es, vx;
es = sqrt (pow (10.0, ripple / 10.0) - 1.0);
vx = (1.0 / np) * asinh (1.0 / es);
rp = rp * sinh (vx);
ip = ip * cosh (vx);
} else if (type == 2) {
gdouble es, vx;
es = sqrt (pow (10.0, ripple / 10.0) - 1.0);
vx = (1.0 / np) * asinh (es);
rp = rp * sinh (vx);
ip = ip * cosh (vx);
}
/* Calculate inverse of the pole location to move from
* type I to type II */
if (type == 2) {
gdouble mag2 = rp * rp + ip * ip;
rp /= mag2;
ip /= mag2;
}
/* Calculate zero location for frequency 1 on the
* unit circle for type 2 */
if (type == 2) {
gdouble angle = G_PI / (np * 2.0) + ((p - 1) * G_PI) / (np);
gdouble mag2;
iz = cos (angle);
mag2 = iz * iz;
iz /= mag2;
}
/* Convert from s-domain to z-domain by
* using the bilinear Z-transform, i.e.
* substitute s by (2/t)*((z-1)/(z+1))
* with t = 2 * tan(0.5).
*/
if (type == 1) {
gdouble t, m, d;
t = 2.0 * tan (0.5);
m = rp * rp + ip * ip;
d = 4.0 - 4.0 * rp * t + m * t * t;
x0 = (t * t) / d;
x1 = 2.0 * x0;
x2 = x0;
y1 = (8.0 - 2.0 * m * t * t) / d;
y2 = (-4.0 - 4.0 * rp * t - m * t * t) / d;
} else {
gdouble t, m, d;
t = 2.0 * tan (0.5);
m = rp * rp + ip * ip;
d = 4.0 - 4.0 * rp * t + m * t * t;
x0 = (t * t * iz * iz + 4.0) / d;
x1 = (-8.0 + 2.0 * iz * iz * t * t) / d;
x2 = x0;
y1 = (8.0 - 2.0 * m * t * t) / d;
y2 = (-4.0 - 4.0 * rp * t - m * t * t) / d;
}
/* Convert from lowpass at frequency 1 to either bandpass
* or band reject.
*
* For bandpass substitute z^(-1) with:
*
* -2 -1
* -z + alpha * z - beta
* ----------------------------
* -2 -1
* beta * z - alpha * z + 1
*
* alpha = (2*a*b)/(1+b)
* beta = (b-1)/(b+1)
* a = cos((w1 + w0)/2) / cos((w1 - w0)/2)
* b = tan(1/2) * cot((w1 - w0)/2)
*
* For bandreject substitute z^(-1) with:
*
* -2 -1
* z - alpha * z + beta
* ----------------------------
* -2 -1
* beta * z - alpha * z + 1
*
* alpha = (2*a)/(1+b)
* beta = (1-b)/(1+b)
* a = cos((w1 + w0)/2) / cos((w1 - w0)/2)
* b = tan(1/2) * tan((w1 - w0)/2)
*
*/
{
gdouble a, b, d;
gdouble alpha, beta;
gdouble w0 = 2.0 * G_PI * (filter->lower_frequency / rate);
gdouble w1 = 2.0 * G_PI * (filter->upper_frequency / rate);
if (filter->mode == MODE_BAND_PASS) {
a = cos ((w1 + w0) / 2.0) / cos ((w1 - w0) / 2.0);
b = tan (1.0 / 2.0) / tan ((w1 - w0) / 2.0);
alpha = (2.0 * a * b) / (1.0 + b);
beta = (b - 1.0) / (b + 1.0);
d = 1.0 + beta * (y1 - beta * y2);
*b0 = (x0 + beta * (-x1 + beta * x2)) / d;
*b1 = (alpha * (-2.0 * x0 + x1 + beta * x1 - 2.0 * beta * x2)) / d;
*b2 =
(-x1 - beta * beta * x1 + 2.0 * beta * (x0 + x2) +
alpha * alpha * (x0 - x1 + x2)) / d;
*b3 = (alpha * (x1 + beta * (-2.0 * x0 + x1) - 2.0 * x2)) / d;
*b4 = (beta * (beta * x0 - x1) + x2) / d;
*a1 = (alpha * (2.0 + y1 + beta * y1 - 2.0 * beta * y2)) / d;
*a2 =
(-y1 - beta * beta * y1 - alpha * alpha * (1.0 + y1 - y2) +
2.0 * beta * (-1.0 + y2)) / d;
*a3 = (alpha * (y1 + beta * (2.0 + y1) - 2.0 * y2)) / d;
*a4 = (-beta * beta - beta * y1 + y2) / d;
} else {
a = cos ((w1 + w0) / 2.0) / cos ((w1 - w0) / 2.0);
b = tan (1.0 / 2.0) * tan ((w1 - w0) / 2.0);
alpha = (2.0 * a) / (1.0 + b);
beta = (1.0 - b) / (1.0 + b);
d = -1.0 + beta * (beta * y2 + y1);
*b0 = (-x0 - beta * x1 - beta * beta * x2) / d;
*b1 = (alpha * (2.0 * x0 + x1 + beta * x1 + 2.0 * beta * x2)) / d;
*b2 =
(-x1 - beta * beta * x1 - 2.0 * beta * (x0 + x2) -
alpha * alpha * (x0 + x1 + x2)) / d;
*b3 = (alpha * (x1 + beta * (2.0 * x0 + x1) + 2.0 * x2)) / d;
*b4 = (-beta * beta * x0 - beta * x1 - x2) / d;
*a1 = (alpha * (-2.0 + y1 + beta * y1 + 2.0 * beta * y2)) / d;
*a2 =
-(y1 + beta * beta * y1 + 2.0 * beta * (-1.0 + y2) +
alpha * alpha * (-1.0 + y1 + y2)) / d;
*a3 = (alpha * (beta * (-2.0 + y1) + y1 + 2.0 * y2)) / d;
*a4 = -(-beta * beta + beta * y1 + y2) / d;
}
}
}
static void
generate_coefficients (GstAudioChebBand * filter)
{
gint rate = GST_AUDIO_FILTER_RATE (filter);
if (rate == 0) {
gdouble *a = g_new0 (gdouble, 1);
gdouble *b = g_new0 (gdouble, 1);
a[0] = 1.0;
b[0] = 1.0;
gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
(filter), a, 1, b, 1);
GST_LOG_OBJECT (filter, "rate was not set yet");
return;
}
if (filter->upper_frequency <= filter->lower_frequency) {
gdouble *a = g_new0 (gdouble, 1);
gdouble *b = g_new0 (gdouble, 1);
a[0] = 1.0;
b[0] = (filter->mode == MODE_BAND_PASS) ? 0.0 : 1.0;
gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
(filter), a, 1, b, 1);
GST_LOG_OBJECT (filter, "frequency band had no or negative dimension");
return;
}
if (filter->upper_frequency > rate / 2) {
filter->upper_frequency = rate / 2;
GST_LOG_OBJECT (filter, "clipped upper frequency to nyquist frequency");
}
if (filter->lower_frequency < 0.0) {
filter->lower_frequency = 0.0;
GST_LOG_OBJECT (filter, "clipped lower frequency to 0.0");
}
/* Calculate coefficients for the chebyshev filter */
{
gint np = filter->poles;
gdouble *a, *b;
gint i, p;
a = g_new0 (gdouble, np + 5);
b = g_new0 (gdouble, np + 5);
/* Calculate transfer function coefficients */
a[4] = 1.0;
b[4] = 1.0;
for (p = 1; p <= np / 4; p++) {
gdouble b0, b1, b2, b3, b4, a1, a2, a3, a4;
gdouble *ta = g_new0 (gdouble, np + 5);
gdouble *tb = g_new0 (gdouble, np + 5);
generate_biquad_coefficients (filter, p, &b0, &b1, &b2, &b3, &b4, &a1,
&a2, &a3, &a4);
memcpy (ta, a, sizeof (gdouble) * (np + 5));
memcpy (tb, b, sizeof (gdouble) * (np + 5));
/* add the new coefficients for the new two poles
* to the cascade by multiplication of the transfer
* functions */
for (i = 4; i < np + 5; i++) {
b[i] =
b0 * tb[i] + b1 * tb[i - 1] + b2 * tb[i - 2] + b3 * tb[i - 3] +
b4 * tb[i - 4];
a[i] =
ta[i] - a1 * ta[i - 1] - a2 * ta[i - 2] - a3 * ta[i - 3] -
a4 * ta[i - 4];
}
g_free (ta);
g_free (tb);
}
/* Move coefficients to the beginning of the array to move from
* the transfer function's coefficients to the difference
* equation's coefficients */
for (i = 0; i <= np; i++) {
a[i] = a[i + 4];
b[i] = b[i + 4];
}
/* Normalize to unity gain at frequency 0 and frequency
* 0.5 for bandreject and unity gain at band center frequency
* for bandpass */
if (filter->mode == MODE_BAND_REJECT) {
/* gain is sqrt(H(0)*H(0.5)) */
gdouble gain1 =
gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1, b, np + 1,
1.0, 0.0);
gdouble gain2 =
gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1, b, np + 1,
-1.0, 0.0);
gain1 = sqrt (gain1 * gain2);
for (i = 0; i <= np; i++) {
b[i] /= gain1;
}
} else {
/* gain is H(wc), wc = center frequency */
gdouble w1 = 2.0 * G_PI * (filter->lower_frequency / rate);
gdouble w2 = 2.0 * G_PI * (filter->upper_frequency / rate);
gdouble w0 = (w2 + w1) / 2.0;
gdouble zr = cos (w0), zi = sin (w0);
gdouble gain =
gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1, b, np + 1, zr,
zi);
for (i = 0; i <= np; i++) {
b[i] /= gain;
}
}
gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
(filter), a, np + 1, b, np + 1);
GST_LOG_OBJECT (filter,
"Generated IIR coefficients for the Chebyshev filter");
GST_LOG_OBJECT (filter,
"mode: %s, type: %d, poles: %d, lower-frequency: %.2f Hz, upper-frequency: %.2f Hz, ripple: %.2f dB",
(filter->mode == MODE_BAND_PASS) ? "band-pass" : "band-reject",
filter->type, filter->poles, filter->lower_frequency,
filter->upper_frequency, filter->ripple);
GST_LOG_OBJECT (filter, "%.2f dB gain @ 0Hz",
20.0 * log10 (gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1, b,
np + 1, 1.0, 0.0)));
{
gdouble w1 = 2.0 * G_PI * (filter->lower_frequency / rate);
gdouble w2 = 2.0 * G_PI * (filter->upper_frequency / rate);
gdouble w0 = (w2 + w1) / 2.0;
gdouble zr, zi;
zr = cos (w1);
zi = sin (w1);
GST_LOG_OBJECT (filter, "%.2f dB gain @ %dHz",
20.0 * log10 (gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1,
b, np + 1, zr, zi)), (int) filter->lower_frequency);
zr = cos (w0);
zi = sin (w0);
GST_LOG_OBJECT (filter, "%.2f dB gain @ %dHz",
20.0 * log10 (gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1,
b, np + 1, zr, zi)),
(int) ((filter->lower_frequency + filter->upper_frequency) / 2.0));
zr = cos (w2);
zi = sin (w2);
GST_LOG_OBJECT (filter, "%.2f dB gain @ %dHz",
20.0 * log10 (gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1,
b, np + 1, zr, zi)), (int) filter->upper_frequency);
}
GST_LOG_OBJECT (filter, "%.2f dB gain @ %dHz",
20.0 * log10 (gst_audio_fx_base_iir_filter_calculate_gain (a, np + 1, b,
np + 1, -1.0, 0.0)), rate / 2);
}
}
static void
gst_audio_cheb_band_finalize (GObject * object)
{
GstAudioChebBand *filter = GST_AUDIO_CHEB_BAND (object);
g_mutex_clear (&filter->lock);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_audio_cheb_band_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstAudioChebBand *filter = GST_AUDIO_CHEB_BAND (object);
switch (prop_id) {
case PROP_MODE:
g_mutex_lock (&filter->lock);
filter->mode = g_value_get_enum (value);
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
case PROP_TYPE:
g_mutex_lock (&filter->lock);
filter->type = g_value_get_int (value);
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
case PROP_LOWER_FREQUENCY:
g_mutex_lock (&filter->lock);
filter->lower_frequency = g_value_get_float (value);
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
case PROP_UPPER_FREQUENCY:
g_mutex_lock (&filter->lock);
filter->upper_frequency = g_value_get_float (value);
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
case PROP_RIPPLE:
g_mutex_lock (&filter->lock);
filter->ripple = g_value_get_float (value);
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
case PROP_POLES:
g_mutex_lock (&filter->lock);
filter->poles = GST_ROUND_UP_4 (g_value_get_int (value));
generate_coefficients (filter);
g_mutex_unlock (&filter->lock);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_audio_cheb_band_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstAudioChebBand *filter = GST_AUDIO_CHEB_BAND (object);
switch (prop_id) {
case PROP_MODE:
g_value_set_enum (value, filter->mode);
break;
case PROP_TYPE:
g_value_set_int (value, filter->type);
break;
case PROP_LOWER_FREQUENCY:
g_value_set_float (value, filter->lower_frequency);
break;
case PROP_UPPER_FREQUENCY:
g_value_set_float (value, filter->upper_frequency);
break;
case PROP_RIPPLE:
g_value_set_float (value, filter->ripple);
break;
case PROP_POLES:
g_value_set_int (value, filter->poles);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/* GstAudioFilter vmethod implementations */
static gboolean
gst_audio_cheb_band_setup (GstAudioFilter * base, const GstAudioInfo * info)
{
GstAudioChebBand *filter = GST_AUDIO_CHEB_BAND (base);
generate_coefficients (filter);
return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, info);
}
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