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windowed sinc bandpass filter

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Original commit message from CVS:
windowed sinc bandpass filter
This commit is contained in:
Thomas Vander Stichele 2002-06-27 14:15:51 +00:00
parent 0f022be747
commit cd8df64059
2 changed files with 679 additions and 0 deletions
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368
gst/audiofx/audiowsincband.c Normal file
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/* -*- c-basic-offset: 2 -*-
* GStreamer
* Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
*
* 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/
*/
/* FIXME:
* - this filter is totally unoptimized !
* - we do not destroy the allocated memory for filters and residue
* - this might be improved upon with bytestream
*/
#include <gst/gst.h>
#include "gstfilter.h"
#include <math.h> /* M_PI */
#include <string.h> /* memmove */
GstElementDetails gst_bpwsinc_details = {
"BPWSinc",
"Filter/Audio/Effect",
"Band-Pass Windowed sinc filter",
VERSION,
"Thomas <thomas@apestaart.org>",
"(C) 2002 Steven W. Smith",
};
enum {
/* FILL ME */
LAST_SIGNAL
};
enum {
ARG_0,
ARG_LENGTH,
ARG_LOWER_FREQUENCY,
ARG_UPPER_FREQUENCY,
};
#define GST_TYPE_BPWSINC \
(gst_bpwsinc_get_type())
#define GST_BPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BPWSINC,GstBPWSinc))
#define GST_BPWSINC_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ULAW,GstBPWSinc))
#define GST_IS_BPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BPWSINC))
#define GST_IS_BPWSINC_CLASS(obj) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BPWSINC))
typedef struct _GstBPWSinc GstBPWSinc;
typedef struct _GstBPWSincClass GstBPWSincClass;
struct _GstBPWSinc
{
GstElement element;
GstPad *sinkpad, *srcpad;
double frequency;
double lower_frequency, upper_frequency;
int wing_size; /* length of a "wing" of the filter;
actual length is 2 * wing_size + 1 */
gfloat *residue; /* buffer for left-over samples from previous buffer */
double *kernel;
};
struct _GstBPWSincClass
{
GstElementClass parent_class;
};
static void gst_bpwsinc_class_init (GstBPWSincClass * klass);
static void gst_bpwsinc_init (GstBPWSinc * filter);
static void gst_bpwsinc_set_property (GObject * object, guint prop_id,
const GValue * value,
GParamSpec * pspec);
static void gst_bpwsinc_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_bpwsinc_chain (GstPad * pad, GstBuffer * buf);
static GstPadConnectReturn
gst_bpwsinc_sink_connect (GstPad * pad, GstCaps * caps);
static GstElementClass *parent_class = NULL;
/*static guint gst_bpwsinc_signals[LAST_SIGNAL] = { 0 }; */
GType gst_bpwsinc_get_type (void)
{
static GType bpwsinc_type = 0;
if (!bpwsinc_type) {
static const GTypeInfo bpwsinc_info = {
sizeof (GstBPWSincClass), NULL, NULL,
(GClassInitFunc) gst_bpwsinc_class_init, NULL, NULL,
sizeof (GstBPWSinc), 0,
(GInstanceInitFunc) gst_bpwsinc_init,
};
bpwsinc_type = g_type_register_static (GST_TYPE_ELEMENT, "GstBPWSinc",
&bpwsinc_info, 0);
}
return bpwsinc_type;
}
static void
gst_bpwsinc_class_init (GstBPWSincClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_LOWER_FREQUENCY,
g_param_spec_double ("lower-frequency", "Lower Frequency",
"Cut-off lower frequency (relative to sample rate)",
0.0, 0.5,
0, G_PARAM_READWRITE));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_UPPER_FREQUENCY,
g_param_spec_double ("upper-frequency", "Upper Frequency",
"Cut-off upper frequency (relative to sample rate)",
0.0, 0.5,
0, G_PARAM_READWRITE));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_LENGTH,
g_param_spec_int ("length", "Length",
"N such that the filter length = 2N + 1",
1, G_MAXINT,
1, G_PARAM_READWRITE));
gobject_class->set_property = gst_bpwsinc_set_property;
gobject_class->get_property = gst_bpwsinc_get_property;
}
static void
gst_bpwsinc_init (GstBPWSinc * filter)
{
filter->sinkpad = gst_pad_new_from_template (gst_filter_sink_factory (), "sink");
gst_pad_set_chain_function (filter->sinkpad, gst_bpwsinc_chain);
gst_pad_set_connect_function (filter->sinkpad, gst_bpwsinc_sink_connect);
gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);
filter->srcpad = gst_pad_new_from_template (gst_filter_src_factory (), "src");
gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);
filter->wing_size = 50;
filter->lower_frequency = 0.25;
filter->upper_frequency = 0.3;
filter->kernel = NULL;
}
static GstPadConnectReturn
gst_bpwsinc_sink_connect (GstPad * pad, GstCaps * caps)
{
int i = 0;
double sum = 0.0;
int len = 0;
double *kernel_lp, *kernel_hp;
GstBPWSinc *filter = GST_BPWSINC (gst_pad_get_parent (pad));
g_assert (GST_IS_PAD (pad));
g_assert (caps != NULL);
if (!GST_CAPS_IS_FIXED (caps))
return GST_PAD_CONNECT_DELAYED;
if (gst_pad_try_set_caps (filter->srcpad, caps))
{
len = filter->wing_size;
/* fill the lp kernel */
GST_DEBUG (GST_CAT_PLUGIN_INFO,
"bpwsinc: initializing LP kernel of length %d with cut-off %f",
len * 2 + 1, filter->lower_frequency);
kernel_lp = (double *) g_malloc (sizeof (double) * (2 * len + 1));
for (i = 0; i <= len * 2; ++i)
{
if (i == len)
kernel_lp[i] = 2 * M_PI * filter->lower_frequency;
else
kernel_lp[i] = sin (2 * M_PI * filter->lower_frequency * (i - len))
/ (i - len);
/* Blackman windowing */
kernel_lp[i] *= (0.42 - 0.5 * cos (M_PI * i / len)
+ 0.08 * cos (2 * M_PI * i / len));
}
/* normalize for unity gain at DC
* FIXME: sure this is not supposed to be quadratic ? */
sum = 0.0;
for (i = 0; i <= len * 2; ++i) sum += kernel_lp[i];
for (i = 0; i <= len * 2; ++i) kernel_lp[i] /= sum;
/* fill the hp kernel */
GST_DEBUG (GST_CAT_PLUGIN_INFO,
"bpwsinc: initializing HP kernel of length %d with cut-off %f",
len * 2 + 1, filter->upper_frequency);
kernel_hp = (double *) g_malloc (sizeof (double) * (2 * len + 1));
for (i = 0; i <= len * 2; ++i)
{
if (i == len)
kernel_hp[i] = 2 * M_PI * filter->upper_frequency;
else
kernel_hp[i] = sin (2 * M_PI * filter->upper_frequency * (i - len))
/ (i - len);
/* Blackman windowing */
kernel_hp[i] *= (0.42 - 0.5 * cos (M_PI * i / len)
+ 0.08 * cos (2 * M_PI * i / len));
}
/* normalize for unity gain at DC
* FIXME: sure this is not supposed to be quadratic ? */
sum = 0.0;
for (i = 0; i <= len * 2; ++i) sum += kernel_hp[i];
for (i = 0; i <= len * 2; ++i) kernel_hp[i] /= sum;
/* do spectral inversion to get a HP filter */
for (i = 0; i <= len * 2; ++i) kernel_hp[i] = -kernel_hp[i];
kernel_hp[len] += 1;
/* combine the two filters */
filter->kernel = (double *) g_malloc (sizeof (double) * (2 * len + 1));
for (i = 0; i <= len * 2; ++i)
filter->kernel[i] = kernel_lp[i] + kernel_hp[i];
/* do spectral inversion to go from band reject to bandpass */
for (i = 0; i <= len * 2; ++i) filter->kernel[i] = -filter->kernel[i];
filter->kernel[len] += 1;
/* free the helper kernels */
g_free (kernel_lp);
g_free (kernel_hp);
/* set up the residue memory space */
filter->residue = (gfloat *) g_malloc (sizeof (gfloat) * (len * 2 + 1));
for (i = 0; i <= len * 2; ++i) filter->residue[i] = 0.0;
return GST_PAD_CONNECT_OK;
}
return GST_PAD_CONNECT_REFUSED;
}
static void
gst_bpwsinc_chain (GstPad * pad, GstBuffer * buf)
{
GstBPWSinc *filter;
gfloat *src;
gfloat *input;
gint residue_samples;
gint input_samples;
gint total_samples;
int i, j;
filter = GST_BPWSINC (gst_pad_get_parent (pad));
/* FIXME: out of laziness, we copy the left-over bit from last buffer
* together with the incoming buffer to a new buffer to make the loop
* easy; this could be a lot more optimized though
* to make amends we keep the incoming buffer around and write our
* output samples there */
src = (gfloat *) GST_BUFFER_DATA (buf);
residue_samples = filter->wing_size * 2 + 1;
input_samples = GST_BUFFER_SIZE (buf) / sizeof (gfloat);
total_samples = residue_samples + input_samples;
input = (gfloat *) g_malloc (sizeof (gfloat) * total_samples);
/* copy the left-over bit */
memcpy (input, filter->residue, sizeof (gfloat) * residue_samples);
/* copy the new buffer */
memcpy (&input[residue_samples], src, sizeof (gfloat) * input_samples);
/* copy the tail of the current input buffer to the residue */
memcpy (filter->residue, &src[input_samples - residue_samples],
sizeof (gfloat) * residue_samples);
/* convolution */
/* since we copied the previous set of samples we needed before the actual
* input data, we need to add the filter length to our indices for input */
for (i = 0; i < input_samples; ++i)
{
src[i] = 0.0;
for (j = 0; j < residue_samples; ++j)
src[i] += input[i - j + residue_samples] * filter->kernel[j];
}
g_free (input);
gst_pad_push (filter->srcpad, buf);
}
static void
gst_bpwsinc_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec)
{
GstBPWSinc *filter;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_BPWSINC (object));
filter = GST_BPWSINC (object);
switch (prop_id) {
case ARG_LENGTH:
filter->wing_size = g_value_get_int (value);
break;
case ARG_LOWER_FREQUENCY:
filter->lower_frequency = g_value_get_double (value);
break;
case ARG_UPPER_FREQUENCY:
filter->upper_frequency = g_value_get_double (value);
break;
default:
break;
}
}
static void
gst_bpwsinc_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec)
{
GstBPWSinc *filter;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_BPWSINC (object));
filter = GST_BPWSINC (object);
switch (prop_id) {
case ARG_LENGTH:
g_value_set_int (value, filter->wing_size);
break;
case ARG_LOWER_FREQUENCY:
g_value_set_double (value, filter->lower_frequency);
break;
case ARG_UPPER_FREQUENCY:
g_value_set_double (value, filter->upper_frequency);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}

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gst/audiofx/audiowsinclimit.c Normal file
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/* -*- c-basic-offset: 2 -*-
* GStreamer
* Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
*
* 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/
*/
/* FIXME:
* - this filter is totally unoptimized !
* - we do not destroy the allocated memory for filters and residue
* - this might be improved upon with bytestream
*/
#include <gst/gst.h>
#include "gstfilter.h"
#include <math.h> /* M_PI */
#include <string.h> /* memmove */
GstElementDetails gst_lpwsinc_details = {
"LPWSinc",
"Filter/Audio/Effect",
"Low-pass Windowed sinc filter",
VERSION,
"Thomas <thomas@apestaart.org>",
"(C) 2002 Steven W. Smith",
};
enum {
/* FILL ME */
LAST_SIGNAL
};
enum {
ARG_0,
ARG_LENGTH,
ARG_FREQUENCY,
};
#define GST_TYPE_LPWSINC \
(gst_lpwsinc_get_type())
#define GST_LPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LPWSINC,GstLPWSinc))
#define GST_LPWSINC_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ULAW,GstLPWSinc))
#define GST_IS_LPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LPWSINC))
#define GST_IS_LPWSINC_CLASS(obj) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_LPWSINC))
typedef struct _GstLPWSinc GstLPWSinc;
typedef struct _GstLPWSincClass GstLPWSincClass;
struct _GstLPWSinc
{
GstElement element;
GstPad *sinkpad, *srcpad;
double frequency;
int wing_size; /* length of a "wing" of the filter;
actual length is 2 * wing_size + 1 */
gfloat *residue; /* buffer for left-over samples from previous buffer */
double *kernel;
};
struct _GstLPWSincClass
{
GstElementClass parent_class;
};
static void gst_lpwsinc_class_init (GstLPWSincClass * klass);
static void gst_lpwsinc_init (GstLPWSinc * filter);
static void gst_lpwsinc_set_property (GObject * object, guint prop_id,
const GValue * value,
GParamSpec * pspec);
static void gst_lpwsinc_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_lpwsinc_chain (GstPad * pad, GstBuffer * buf);
static GstPadConnectReturn
gst_lpwsinc_sink_connect (GstPad * pad, GstCaps * caps);
static GstElementClass *parent_class = NULL;
/*static guint gst_lpwsinc_signals[LAST_SIGNAL] = { 0 }; */
GType gst_lpwsinc_get_type (void)
{
static GType lpwsinc_type = 0;
if (!lpwsinc_type) {
static const GTypeInfo lpwsinc_info = {
sizeof (GstLPWSincClass), NULL, NULL,
(GClassInitFunc) gst_lpwsinc_class_init, NULL, NULL,
sizeof (GstLPWSinc), 0,
(GInstanceInitFunc) gst_lpwsinc_init,
};
lpwsinc_type = g_type_register_static (GST_TYPE_ELEMENT, "GstLPWSinc",
&lpwsinc_info, 0);
}
return lpwsinc_type;
}
static void
gst_lpwsinc_class_init (GstLPWSincClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FREQUENCY,
g_param_spec_double ("frequency", "Frequency",
"Cut-off Frequency relative to sample rate)",
0.0, 0.5,
0, G_PARAM_READWRITE));
g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_LENGTH,
g_param_spec_int ("length", "Length",
"N such that the filter length = 2N + 1",
1, G_MAXINT,
1, G_PARAM_READWRITE));
gobject_class->set_property = gst_lpwsinc_set_property;
gobject_class->get_property = gst_lpwsinc_get_property;
}
static void
gst_lpwsinc_init (GstLPWSinc * filter)
{
filter->sinkpad = gst_pad_new_from_template (gst_filter_sink_factory (), "sink");
gst_pad_set_chain_function (filter->sinkpad, gst_lpwsinc_chain);
gst_pad_set_connect_function (filter->sinkpad, gst_lpwsinc_sink_connect);
gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);
filter->srcpad = gst_pad_new_from_template (gst_filter_src_factory (), "src");
gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);
filter->wing_size = 50;
filter->frequency = 0.25;
filter->kernel = NULL;
}
static GstPadConnectReturn
gst_lpwsinc_sink_connect (GstPad * pad, GstCaps * caps)
{
int i = 0;
double sum = 0.0;
int len = 0;
GstLPWSinc *filter = GST_LPWSINC (gst_pad_get_parent (pad));
g_assert (GST_IS_PAD (pad));
g_assert (caps != NULL);
if (!GST_CAPS_IS_FIXED (caps))
return GST_PAD_CONNECT_DELAYED;
if (gst_pad_try_set_caps (filter->srcpad, caps))
{
/* connection works, so init the filter */
/* FIXME: remember to free it */
/* fill the kernel */
g_print ("DEBUG: initing filter kernel\n");
len = filter->wing_size;
GST_DEBUG (GST_CAT_PLUGIN_INFO,
"lpwsinc: initializing filter kernel of length %d", len * 2 + 1);
filter->kernel = (double *) g_malloc (sizeof (double) * (2 * len + 1));
for (i = 0; i <= len * 2; ++i)
{
if (i == len)
filter->kernel[i] = 2 * M_PI * filter->frequency;
else
filter->kernel[i] = sin (2 * M_PI * filter->frequency * (i - len))
/ (i - len);
/* windowing */
filter->kernel[i] *= (0.54 - 0.46 * cos (M_PI * i / len));
}
/* normalize for unity gain at DC
* FIXME: sure this is not supposed to be quadratic ? */
for (i = 0; i <= len * 2; ++i) sum += filter->kernel[i];
for (i = 0; i <= len * 2; ++i) filter->kernel[i] /= sum;
/* set up the residue memory space */
filter->residue = (gfloat *) g_malloc (sizeof (gfloat) * (len * 2 + 1));
for (i = 0; i <= len * 2; ++i) filter->residue[i] = 0.0;
return GST_PAD_CONNECT_OK;
}
return GST_PAD_CONNECT_REFUSED;
}
static void
gst_lpwsinc_chain (GstPad * pad, GstBuffer * buf)
{
GstLPWSinc *filter;
gfloat *src;
gfloat *input;
gint residue_samples;
gint input_samples;
gint total_samples;
int i, j;
filter = GST_LPWSINC (gst_pad_get_parent (pad));
/* FIXME: out of laziness, we copy the left-over bit from last buffer
* together with the incoming buffer to a new buffer to make the loop
* easy; this could be a lot more optimized though
* to make amends we keep the incoming buffer around and write our
* output samples there */
src = (gfloat *) GST_BUFFER_DATA (buf);
residue_samples = filter->wing_size * 2 + 1;
input_samples = GST_BUFFER_SIZE (buf) / sizeof (gfloat);
total_samples = residue_samples + input_samples;
input = (gfloat *) g_malloc (sizeof (gfloat) * total_samples);
/* copy the left-over bit */
memcpy (input, filter->residue, sizeof (gfloat) * residue_samples);
/* copy the new buffer */
memcpy (&input[residue_samples], src, sizeof (gfloat) * input_samples);
/* copy the tail of the current input buffer to the residue */
memcpy (filter->residue, &src[input_samples - residue_samples],
sizeof (gfloat) * residue_samples);
/* convolution */
/* since we copied the previous set of samples we needed before the actual
* input data, we need to add the filter length to our indices for input */
for (i = 0; i < input_samples; ++i)
{
src[i] = 0.0;
for (j = 0; j < residue_samples; ++j)
src[i] += input[i - j + residue_samples] * filter->kernel[j];
}
g_free (input);
gst_pad_push (filter->srcpad, buf);
}
static void
gst_lpwsinc_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec)
{
GstLPWSinc *filter;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_LPWSINC (object));
filter = GST_LPWSINC (object);
switch (prop_id) {
case ARG_LENGTH:
filter->wing_size = g_value_get_int (value);
break;
case ARG_FREQUENCY:
filter->frequency = g_value_get_double (value);
break;
default:
break;
}
}
static void
gst_lpwsinc_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec)
{
GstLPWSinc *filter;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_LPWSINC (object));
filter = GST_LPWSINC (object);
switch (prop_id) {
case ARG_LENGTH:
g_value_set_int (value, filter->wing_size);
break;
case ARG_FREQUENCY:
g_value_set_double (value, filter->frequency);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}