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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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highly unoptimized windowed sinc filter
Original commit message from CVS: highly unoptimized windowed sinc filter
This commit is contained in:
parent
6b4bd943ce
commit
c903e6470e
5 changed files with 317 additions and 2 deletions
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@ -2,7 +2,7 @@ plugindir = $(libdir)/gst
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plugin_LTLIBRARIES = libgstfilter.la
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plugin_LTLIBRARIES = libgstfilter.la
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libgstfilter_la_SOURCES = gstfilter.c gstiir.c iir.c
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libgstfilter_la_SOURCES = gstfilter.c gstiir.c iir.c gstwsinc.c
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libgstfilter_la_CFLAGS = $(GST_CFLAGS)
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libgstfilter_la_CFLAGS = $(GST_CFLAGS)
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libgstfilter_la_LIBADD =
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libgstfilter_la_LIBADD =
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libgstfilter_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
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libgstfilter_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
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@ -32,6 +32,7 @@ struct _elements_entry {
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static struct _elements_entry _elements[] = {
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static struct _elements_entry _elements[] = {
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{ "iir", gst_iir_get_type, &gst_iir_details, NULL },
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{ "iir", gst_iir_get_type, &gst_iir_details, NULL },
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{ "wsinc", gst_wsinc_get_type, &gst_wsinc_details, NULL },
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{ NULL, 0 },
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{ NULL, 0 },
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};
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};
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@ -31,4 +31,7 @@ extern GstElementDetails gst_iir_details;
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extern GstPadTemplate *gst_filter_sink_factory ();
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extern GstPadTemplate *gst_filter_sink_factory ();
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extern GstPadTemplate *gst_filter_src_factory ();
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extern GstPadTemplate *gst_filter_src_factory ();
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GType gst_wsinc_get_type (void);
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extern GstElementDetails gst_wsinc_details;
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#endif /* __GST_FILTER_H__ */
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#endif /* __GST_FILTER_H__ */
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@ -136,7 +136,7 @@ gst_iir_class_init (GstIIRClass * klass)
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g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_STAGES,
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g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_STAGES,
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g_param_spec_int ("stages", "Stages", "Number of filter stages",
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g_param_spec_int ("stages", "Stages", "Number of filter stages",
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1, G_MAXINT,
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1, G_MAXINT,
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0, G_PARAM_READWRITE));
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1, G_PARAM_READWRITE));
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gobject_class->set_property = gst_iir_set_property;
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gobject_class->set_property = gst_iir_set_property;
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gobject_class->get_property = gst_iir_get_property;
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gobject_class->get_property = gst_iir_get_property;
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311
gst/filter/gstwsinc.c
Normal file
311
gst/filter/gstwsinc.c
Normal file
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@ -0,0 +1,311 @@
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/* -*- c-basic-offset: 2 -*-
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* GStreamer
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* Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/* this windowed sinc filter is taken from the freely downloadable DSP book,
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* "The Scientist and Engineer's Guide to Digital Signal Processing",
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* chapter 16
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* available at http://www.dspguide.com/
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*/
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/* FIXME:
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* - this filter is totally unoptimized !
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* - we do not destroy the allocated memory for filters and residue
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* - this might be improved upon with bytestream
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*/
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#include <gst/gst.h>
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#include "gstfilter.h"
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#include <math.h> /* M_PI */
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#include <string.h> /* memmove */
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GstElementDetails gst_wsinc_details = {
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"WSinc",
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"Filter/Audio/Effect",
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"Windowed sinc filter",
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VERSION,
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"Thomas <thomas@apestaart.org>",
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"(C) 2002 Steven W. Smith",
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};
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enum {
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/* FILL ME */
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LAST_SIGNAL
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};
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enum {
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ARG_0,
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ARG_LENGTH,
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ARG_FREQUENCY,
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};
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#define GST_TYPE_WSINC \
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(gst_wsinc_get_type())
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#define GST_WSINC(obj) \
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(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_WSINC,GstWSinc))
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#define GST_WSINC_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ULAW,GstWSinc))
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#define GST_IS_WSINC(obj) \
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(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_WSINC))
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#define GST_IS_WSINC_CLASS(obj) \
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(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_WSINC))
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typedef struct _GstWSinc GstWSinc;
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typedef struct _GstWSincClass GstWSincClass;
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struct _GstWSinc
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{
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GstElement element;
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GstPad *sinkpad, *srcpad;
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double frequency;
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int wing_size; /* length of a "wing" of the filter;
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actual length is 2 * wing_size + 1 */
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gfloat *residue; /* buffer for left-over samples from previous buffer */
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double *kernel;
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};
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struct _GstWSincClass
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{
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GstElementClass parent_class;
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};
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static void gst_wsinc_class_init (GstWSincClass * klass);
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static void gst_wsinc_init (GstWSinc * filter);
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static void gst_wsinc_set_property (GObject * object, guint prop_id,
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const GValue * value,
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GParamSpec * pspec);
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static void gst_wsinc_get_property (GObject * object, guint prop_id,
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GValue * value, GParamSpec * pspec);
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static void gst_wsinc_chain (GstPad * pad, GstBuffer * buf);
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static GstPadConnectReturn
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gst_wsinc_sink_connect (GstPad * pad, GstCaps * caps);
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static GstElementClass *parent_class = NULL;
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/*static guint gst_wsinc_signals[LAST_SIGNAL] = { 0 }; */
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GType gst_wsinc_get_type (void)
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{
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static GType wsinc_type = 0;
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if (!wsinc_type) {
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static const GTypeInfo wsinc_info = {
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sizeof (GstWSincClass), NULL, NULL,
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(GClassInitFunc) gst_wsinc_class_init, NULL, NULL,
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sizeof (GstWSinc), 0,
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(GInstanceInitFunc) gst_wsinc_init,
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};
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wsinc_type = g_type_register_static (GST_TYPE_ELEMENT, "GstWSinc",
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&wsinc_info, 0);
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}
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return wsinc_type;
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}
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static void
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gst_wsinc_class_init (GstWSincClass * klass)
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{
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GObjectClass *gobject_class;
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GstElementClass *gstelement_class;
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gobject_class = (GObjectClass *) klass;
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gstelement_class = (GstElementClass *) klass;
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parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
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g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_FREQUENCY,
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g_param_spec_double ("frequency", "Frequency",
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"Cut-off Frequency relative to sample rate)",
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0.0, 0.5,
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0, G_PARAM_READWRITE));
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g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_LENGTH,
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g_param_spec_int ("length", "Length",
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"N such that the filter length = 2N + 1",
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1, G_MAXINT,
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1, G_PARAM_READWRITE));
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gobject_class->set_property = gst_wsinc_set_property;
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gobject_class->get_property = gst_wsinc_get_property;
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}
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static void
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gst_wsinc_init (GstWSinc * filter)
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{
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filter->sinkpad = gst_pad_new_from_template (gst_filter_sink_factory (), "sink");
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gst_pad_set_chain_function (filter->sinkpad, gst_wsinc_chain);
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gst_pad_set_connect_function (filter->sinkpad, gst_wsinc_sink_connect);
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gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);
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filter->srcpad = gst_pad_new_from_template (gst_filter_src_factory (), "src");
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gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);
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filter->wing_size = 50;
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filter->frequency = 0.25;
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filter->kernel = NULL;
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}
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static GstPadConnectReturn
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gst_wsinc_sink_connect (GstPad * pad, GstCaps * caps)
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{
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int i = 0;
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double sum = 0.0;
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int len = 0;
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GstWSinc *filter = GST_WSINC (gst_pad_get_parent (pad));
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g_assert (GST_IS_PAD (pad));
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g_assert (caps != NULL);
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if (!GST_CAPS_IS_FIXED (caps))
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return GST_PAD_CONNECT_DELAYED;
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if (gst_pad_try_set_caps (filter->srcpad, caps))
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{
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/* connection works, so init the filter */
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/* FIXME: remember to free it */
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/* fill the kernel */
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g_print ("DEBUG: initing filter kernel\n");
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len = filter->wing_size;
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GST_DEBUG (GST_CAT_PLUGIN_INFO,
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"wsinc: initializing filter kernel of length %d", len * 2 + 1);
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filter->kernel = (double *) g_malloc (sizeof (double) * (2 * len + 1));
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for (i = 0; i <= len * 2; ++i)
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{
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if (i == len)
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filter->kernel[i] = 2 * M_PI * filter->frequency;
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else
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filter->kernel[i] = sin (2 * M_PI * filter->frequency * (i - len))
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/ (i - len);
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/* windowing */
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filter->kernel[i] *= (0.54 - 0.46 * cos (M_PI * i / len));
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}
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/* normalize for unity gain at DC
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* FIXME: sure this is not supposed to be quadratic ? */
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for (i = 0; i <= len * 2; ++i) sum += filter->kernel[i];
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for (i = 0; i <= len * 2; ++i) filter->kernel[i] /= sum;
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/* set up the residue memory space */
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filter->residue = (gfloat *) g_malloc (sizeof (gfloat) * (len * 2 + 1));
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for (i = 0; i <= len * 2; ++i) filter->residue[i] = 0.0;
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return GST_PAD_CONNECT_OK;
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}
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return GST_PAD_CONNECT_REFUSED;
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}
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static void
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gst_wsinc_chain (GstPad * pad, GstBuffer * buf)
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{
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GstWSinc *filter;
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gfloat *src;
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gfloat *input;
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gint residue_samples;
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gint input_samples;
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gint total_samples;
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int i, j;
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filter = GST_WSINC (gst_pad_get_parent (pad));
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/* FIXME: out of laziness, we copy the left-over bit from last buffer
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* together with the incoming buffer to a new buffer to make the loop
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* easy; this could be a lot more optimized though
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* to make amends we keep the incoming buffer around and write our
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* output samples there */
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src = (gfloat *) GST_BUFFER_DATA (buf);
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residue_samples = filter->wing_size * 2 + 1;
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input_samples = GST_BUFFER_SIZE (buf) / sizeof (gfloat);
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total_samples = residue_samples + input_samples;
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input = (gfloat *) g_malloc (sizeof (gfloat) * total_samples);
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/* copy the left-over bit */
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memcpy (input, filter->residue, sizeof (gfloat) * residue_samples);
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/* copy the new buffer */
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memcpy (&input[residue_samples], src, sizeof (gfloat) * input_samples);
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/* copy the tail of the current input buffer to the residue */
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memcpy (filter->residue, &src[input_samples - residue_samples],
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sizeof (gfloat) * residue_samples);
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/* convolution */
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/* since we copied the previous set of samples we needed before the actual
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* input data, we need to add the filter length to our indices for input */
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for (i = 0; i < input_samples; ++i)
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{
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src[i] = 0.0;
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for (j = 0; j < residue_samples; ++j)
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src[i] += input[i - j + residue_samples] * filter->kernel[j];
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}
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g_free (input);
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gst_pad_push (filter->srcpad, buf);
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}
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static void
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gst_wsinc_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec)
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{
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GstWSinc *filter;
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/* it's not null if we got it, but it might not be ours */
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g_return_if_fail (GST_IS_WSINC (object));
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filter = GST_WSINC (object);
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switch (prop_id) {
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case ARG_LENGTH:
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filter->wing_size = g_value_get_int (value);
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break;
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case ARG_FREQUENCY:
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filter->frequency = g_value_get_double (value);
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break;
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default:
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break;
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}
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}
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static void
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gst_wsinc_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec)
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{
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GstWSinc *filter;
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/* it's not null if we got it, but it might not be ours */
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g_return_if_fail (GST_IS_WSINC (object));
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filter = GST_WSINC (object);
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switch (prop_id) {
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case ARG_LENGTH:
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g_value_set_int (value, filter->wing_size);
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break;
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case ARG_FREQUENCY:
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g_value_set_double (value, filter->frequency);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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