gst/filter/gstlpwsinc.c - mtk-gst-plugins-bad - Git at Google

 /* -*- 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
  */

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 #include <gst/gst.h>
 #include "gstfilter.h"
 #include <math.h>		/* M_PI */
 #include <string.h>		/* memmove */

 static GstElementDetails gst_lpwsinc_details = GST_ELEMENT_DETAILS (
   "LPWSinc",
   "Filter/Effect/Audio",
   "Low-pass Windowed sinc filter",
   "Thomas <thomas@apestaart.org>, "
   "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_base_init		(gpointer g_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, GstData *_data);
 static GstPadLinkReturn
        gst_lpwsinc_sink_connect 		(GstPad * pad, const 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),
       gst_lpwsinc_base_init,
       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_base_init (gpointer g_class)
 {
   GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

   /* register src pads */
   gst_element_class_add_pad_template (element_class,
       gst_static_pad_template_get (&gst_filter_src_template));
   gst_element_class_add_pad_template (element_class,
     gst_static_pad_template_get (&gst_filter_sink_template));

   gst_element_class_set_details (element_class, &gst_lpwsinc_details);
 }

 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_static_pad_template_get (&gst_filter_sink_template), "sink");
   gst_pad_set_chain_function (filter->sinkpad, gst_lpwsinc_chain);
   gst_pad_set_link_function (filter->sinkpad, gst_lpwsinc_sink_connect);
   gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);

   filter->srcpad = gst_pad_new_from_template (
       gst_static_pad_template_get (&gst_filter_src_template), "src");
   gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);

   filter->wing_size = 50;
   filter->frequency = 0.25;
   filter->kernel = NULL;
 }

 static GstPadLinkReturn
 gst_lpwsinc_sink_connect (GstPad * pad, const GstCaps * caps)
 {
   int i = 0;
   double sum = 0.0;
   int len = 0;
   GstLPWSinc *filter = GST_LPWSINC (gst_pad_get_parent (pad));
   GstPadLinkReturn set_retval;

   g_assert (GST_IS_PAD (pad));
   g_assert (caps != NULL);

   set_retval = gst_pad_try_set_caps(filter->srcpad, caps);

   if (set_retval > 0)
   {
     /* 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 (
 	       "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 set_retval;
 }

 static void
 gst_lpwsinc_chain (GstPad * pad, GstData *_data)
 {
   GstBuffer *buf = GST_BUFFER (_data);
   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 */

   /* get a writable buffer */
   buf = gst_buffer_copy_on_write (buf);

   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, GST_DATA (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;
   }
 }
	/* -- 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
	*/

	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif
	#include <gst/gst.h>
	#include "gstfilter.h"
	#include <math.h> /* M_PI */
	#include <string.h> /* memmove */

	static GstElementDetails gst_lpwsinc_details = GST_ELEMENT_DETAILS (
	"LPWSinc",
	"Filter/Effect/Audio",
	"Low-pass Windowed sinc filter",
	"Thomas <thomas@apestaart.org>, "
	"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_base_init (gpointer g_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, GstData *_data);
	static GstPadLinkReturn
	gst_lpwsinc_sink_connect (GstPad * pad, const 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),
	gst_lpwsinc_base_init,
	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_base_init (gpointer g_class)
	{
	GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

	/* register src pads */
	gst_element_class_add_pad_template (element_class,
	gst_static_pad_template_get (&gst_filter_src_template));
	gst_element_class_add_pad_template (element_class,
	gst_static_pad_template_get (&gst_filter_sink_template));

	gst_element_class_set_details (element_class, &gst_lpwsinc_details);
	}

	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_static_pad_template_get (&gst_filter_sink_template), "sink");
	gst_pad_set_chain_function (filter->sinkpad, gst_lpwsinc_chain);
	gst_pad_set_link_function (filter->sinkpad, gst_lpwsinc_sink_connect);
	gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);

	filter->srcpad = gst_pad_new_from_template (
	gst_static_pad_template_get (&gst_filter_src_template), "src");
	gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);

	filter->wing_size = 50;
	filter->frequency = 0.25;
	filter->kernel = NULL;
	}

	static GstPadLinkReturn
	gst_lpwsinc_sink_connect (GstPad * pad, const GstCaps * caps)
	{
	int i = 0;
	double sum = 0.0;
	int len = 0;
	GstLPWSinc *filter = GST_LPWSINC (gst_pad_get_parent (pad));
	GstPadLinkReturn set_retval;

	g_assert (GST_IS_PAD (pad));
	g_assert (caps != NULL);

	set_retval = gst_pad_try_set_caps(filter->srcpad, caps);

	if (set_retval > 0)
	{
	/* 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 (
	"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 set_retval;
	}

	static void
	gst_lpwsinc_chain (GstPad * pad, GstData *_data)
	{
	GstBuffer *buf = GST_BUFFER (_data);
	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 */

	/* get a writable buffer */
	buf = gst_buffer_copy_on_write (buf);

	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, GST_DATA (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;
	}
	}