gstreamer/gst/audiofx/audiowsincband.c

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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>
*
* 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
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <math.h>
#include <gst/gst.h>
#include <gst/base/gstbasetransform.h>
#include <gst/controller/gstcontroller.h>
#include "gstbpwsinc.h"
#define GST_CAT_DEFAULT gst_bpwsinc_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
static const GstElementDetails bpwsinc_details =
GST_ELEMENT_DETAILS ("Band-pass Windowed sinc filter",
"Filter/Effect/Audio",
"Band-pass Windowed sinc filter",
"Thomas <thomas@apestaart.org>, "
"Steven W. Smith, "
"Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>");
/* Filter signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
PROP_0,
PROP_LENGTH,
PROP_LOWER_FREQUENCY,
PROP_UPPER_FREQUENCY
};
static GstStaticPadTemplate bpwsinc_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-raw-float, "
"rate = (int) [ 1, MAX ], "
"channels = (int) [ 1, MAX ], "
"endianness = (int) BYTE_ORDER, " "width = (int) 32")
);
static GstStaticPadTemplate bpwsinc_src_template = GST_STATIC_PAD_TEMPLATE
("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-raw-float, "
"rate = (int) [ 1, MAX ], "
"channels = (int) [ 1, MAX ], "
"endianness = (int) BYTE_ORDER, " "width = (int) 32")
);
#define DEBUG_INIT(bla) \
GST_DEBUG_CATEGORY_INIT (gst_bpwsinc_debug, "bpwsinc", 0, "Band-pass Windowed sinc filter plugin");
GST_BOILERPLATE_FULL (GstBPWSinc, gst_bpwsinc, GstBaseTransform,
GST_TYPE_BASE_TRANSFORM, DEBUG_INIT);
static void bpwsinc_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void bpwsinc_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstFlowReturn bpwsinc_transform_ip (GstBaseTransform * base,
GstBuffer * outbuf);
static gboolean bpwsinc_set_caps (GstBaseTransform * base, GstCaps * incaps,
GstCaps * outcaps);
/* Element class */
static void
gst_bpwsinc_dispose (GObject * object)
{
G_OBJECT_CLASS (parent_class)->dispose (object);
}
static void
gst_bpwsinc_base_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&bpwsinc_src_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&bpwsinc_sink_template));
gst_element_class_set_details (element_class, &bpwsinc_details);
}
static void
gst_bpwsinc_class_init (GstBPWSincClass * klass)
{
GObjectClass *gobject_class;
GstBaseTransformClass *trans_class;
gobject_class = (GObjectClass *) klass;
trans_class = (GstBaseTransformClass *) klass;
gobject_class->set_property = bpwsinc_set_property;
gobject_class->get_property = bpwsinc_get_property;
gobject_class->dispose = gst_bpwsinc_dispose;
g_object_class_install_property (gobject_class, PROP_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 (gobject_class, PROP_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 (gobject_class, PROP_LENGTH,
g_param_spec_int ("length", "Length",
"N such that the filter length = 2N + 1",
1, G_MAXINT, 1, G_PARAM_READWRITE));
trans_class->transform_ip = GST_DEBUG_FUNCPTR (bpwsinc_transform_ip);
trans_class->set_caps = GST_DEBUG_FUNCPTR (bpwsinc_set_caps);
}
static void
gst_bpwsinc_init (GstBPWSinc * this, GstBPWSincClass * g_class)
{
this->wing_size = 50;
this->lower_frequency = 0.25;
this->upper_frequency = 0.3;
this->kernel = NULL;
}
/* GstBaseTransform vmethod implementations */
/* get notified of caps and plug in the correct process function */
static gboolean
bpwsinc_set_caps (GstBaseTransform * base, GstCaps * incaps, GstCaps * outcaps)
{
int i = 0;
double sum = 0.0;
int len = 0;
double *kernel_lp, *kernel_hp;
GstBPWSinc *this = GST_BPWSINC (base);
GST_DEBUG_OBJECT (this,
"set_caps: in %" GST_PTR_FORMAT " out %" GST_PTR_FORMAT, incaps, outcaps);
len = this->wing_size;
/* fill the lp kernel */
GST_DEBUG ("bpwsinc: initializing LP kernel of length %d with cut-off %f",
len * 2 + 1, this->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 * this->lower_frequency;
else
kernel_lp[i] = sin (2 * M_PI * this->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 ("bpwsinc: initializing HP kernel of length %d with cut-off %f",
len * 2 + 1, this->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 * this->upper_frequency;
else
kernel_hp[i] = sin (2 * M_PI * this->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;
/* combine the two thiss */
this->kernel = (double *) g_malloc (sizeof (double) * (2 * len + 1));
for (i = 0; i <= len * 2; ++i)
this->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)
this->kernel[i] = -this->kernel[i];
this->kernel[len] += 1;
/* free the helper kernels */
g_free (kernel_lp);
g_free (kernel_hp);
/* set up the residue memory space */
this->residue = (gfloat *) g_malloc (sizeof (gfloat) * (len * 2 + 1));
for (i = 0; i <= len * 2; ++i)
this->residue[i] = 0.0;
return TRUE;
}
static GstFlowReturn
bpwsinc_transform_ip (GstBaseTransform * base, GstBuffer * outbuf)
{
GstBPWSinc *this = GST_BPWSINC (base);
GstClockTime timestamp;
gfloat *src;
gfloat *input;
int residue_samples;
gint input_samples;
gint total_samples;
int i, j;
/* don't process data in passthrough-mode */
if (gst_base_transform_is_passthrough (base))
return GST_FLOW_OK;
/* FIXME: subdivide GST_BUFFER_SIZE into small chunks for smooth fades */
timestamp = GST_BUFFER_TIMESTAMP (outbuf);
if (GST_CLOCK_TIME_IS_VALID (timestamp))
gst_object_sync_values (G_OBJECT (this), timestamp);
/* 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 (outbuf);
residue_samples = this->wing_size * 2 + 1;
input_samples = GST_BUFFER_SIZE (outbuf) / sizeof (gfloat);
total_samples = residue_samples + input_samples;
input = (gfloat *) g_malloc (sizeof (gfloat) * total_samples);
/* copy the left-over bit */
memcpy (input, this->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 (this->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] * this->kernel[j];
}
g_free (input);
return GST_FLOW_OK;
}
static void
bpwsinc_set_property (GObject * object, guint prop_id, const GValue * value,
GParamSpec * pspec)
{
GstBPWSinc *this = GST_BPWSINC (object);
g_return_if_fail (GST_IS_BPWSINC (this));
switch (prop_id) {
case PROP_LENGTH:
this->wing_size = g_value_get_int (value);
break;
case PROP_LOWER_FREQUENCY:
this->lower_frequency = g_value_get_double (value);
break;
case PROP_UPPER_FREQUENCY:
this->upper_frequency = g_value_get_double (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
bpwsinc_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstBPWSinc *this = GST_BPWSINC (object);
switch (prop_id) {
case PROP_LENGTH:
g_value_set_int (value, this->wing_size);
break;
case PROP_LOWER_FREQUENCY:
g_value_set_double (value, this->lower_frequency);
break;
case PROP_UPPER_FREQUENCY:
g_value_set_double (value, this->upper_frequency);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}