From c903e6470eea491ec693bab49ad8b023601d42c1 Mon Sep 17 00:00:00 2001 From: Thomas Vander Stichele Date: Thu, 27 Jun 2002 12:38:35 +0000 Subject: [PATCH] highly unoptimized windowed sinc filter Original commit message from CVS: highly unoptimized windowed sinc filter --- gst/filter/Makefile.am | 2 +- gst/filter/gstfilter.c | 1 + gst/filter/gstfilter.h | 3 + gst/filter/gstiir.c | 2 +- gst/filter/gstwsinc.c | 311 +++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 317 insertions(+), 2 deletions(-) create mode 100644 gst/filter/gstwsinc.c diff --git a/gst/filter/Makefile.am b/gst/filter/Makefile.am index 4204955..fd11c10 100644 --- a/gst/filter/Makefile.am +++ b/gst/filter/Makefile.am @@ -2,7 +2,7 @@ plugindir = $(libdir)/gst plugin_LTLIBRARIES = libgstfilter.la -libgstfilter_la_SOURCES = gstfilter.c gstiir.c iir.c +libgstfilter_la_SOURCES = gstfilter.c gstiir.c iir.c gstwsinc.c libgstfilter_la_CFLAGS = $(GST_CFLAGS) libgstfilter_la_LIBADD = libgstfilter_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS) diff --git a/gst/filter/gstfilter.c b/gst/filter/gstfilter.c index 2ed416c..cd9f466 100644 --- a/gst/filter/gstfilter.c +++ b/gst/filter/gstfilter.c @@ -32,6 +32,7 @@ struct _elements_entry { static struct _elements_entry _elements[] = { { "iir", gst_iir_get_type, &gst_iir_details, NULL }, + { "wsinc", gst_wsinc_get_type, &gst_wsinc_details, NULL }, { NULL, 0 }, }; diff --git a/gst/filter/gstfilter.h b/gst/filter/gstfilter.h index a806bb4..a23a144 100644 --- a/gst/filter/gstfilter.h +++ b/gst/filter/gstfilter.h @@ -31,4 +31,7 @@ extern GstElementDetails gst_iir_details; extern GstPadTemplate *gst_filter_sink_factory (); extern GstPadTemplate *gst_filter_src_factory (); +GType gst_wsinc_get_type (void); +extern GstElementDetails gst_wsinc_details; + #endif /* __GST_FILTER_H__ */ diff --git a/gst/filter/gstiir.c b/gst/filter/gstiir.c index 811b6a1..0bbcb05 100644 --- a/gst/filter/gstiir.c +++ b/gst/filter/gstiir.c @@ -136,7 +136,7 @@ gst_iir_class_init (GstIIRClass * klass) g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_STAGES, g_param_spec_int ("stages", "Stages", "Number of filter stages", 1, G_MAXINT, - 0, G_PARAM_READWRITE)); + 1, G_PARAM_READWRITE)); gobject_class->set_property = gst_iir_set_property; gobject_class->get_property = gst_iir_get_property; diff --git a/gst/filter/gstwsinc.c b/gst/filter/gstwsinc.c new file mode 100644 index 0000000..1930045 --- /dev/null +++ b/gst/filter/gstwsinc.c @@ -0,0 +1,311 @@ +/* -*- c-basic-offset: 2 -*- + * GStreamer + * Copyright (C) 1999-2001 Erik Walthinsen + * + * 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 +#include "gstfilter.h" +#include /* M_PI */ +#include /* memmove */ + +GstElementDetails gst_wsinc_details = { + "WSinc", + "Filter/Audio/Effect", + "Windowed sinc filter", + VERSION, + "Thomas ", + "(C) 2002 Steven W. Smith", +}; + +enum { + /* FILL ME */ + LAST_SIGNAL +}; + +enum { + ARG_0, + ARG_LENGTH, + ARG_FREQUENCY, +}; + +#define GST_TYPE_WSINC \ + (gst_wsinc_get_type()) +#define GST_WSINC(obj) \ + (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_WSINC,GstWSinc)) +#define GST_WSINC_CLASS(klass) \ + (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ULAW,GstWSinc)) +#define GST_IS_WSINC(obj) \ + (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_WSINC)) +#define GST_IS_WSINC_CLASS(obj) \ + (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_WSINC)) + +typedef struct _GstWSinc GstWSinc; +typedef struct _GstWSincClass GstWSincClass; + +struct _GstWSinc +{ + 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 _GstWSincClass +{ + GstElementClass parent_class; +}; + +static void gst_wsinc_class_init (GstWSincClass * klass); +static void gst_wsinc_init (GstWSinc * filter); + +static void gst_wsinc_set_property (GObject * object, guint prop_id, + const GValue * value, + GParamSpec * pspec); +static void gst_wsinc_get_property (GObject * object, guint prop_id, + GValue * value, GParamSpec * pspec); + +static void gst_wsinc_chain (GstPad * pad, GstBuffer * buf); +static GstPadConnectReturn + gst_wsinc_sink_connect (GstPad * pad, GstCaps * caps); + +static GstElementClass *parent_class = NULL; +/*static guint gst_wsinc_signals[LAST_SIGNAL] = { 0 }; */ + +GType gst_wsinc_get_type (void) +{ + static GType wsinc_type = 0; + + if (!wsinc_type) { + static const GTypeInfo wsinc_info = { + sizeof (GstWSincClass), NULL, NULL, + (GClassInitFunc) gst_wsinc_class_init, NULL, NULL, + sizeof (GstWSinc), 0, + (GInstanceInitFunc) gst_wsinc_init, + }; + + wsinc_type = g_type_register_static (GST_TYPE_ELEMENT, "GstWSinc", + &wsinc_info, 0); + } + return wsinc_type; +} + +static void +gst_wsinc_class_init (GstWSincClass * 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_wsinc_set_property; + gobject_class->get_property = gst_wsinc_get_property; +} + +static void +gst_wsinc_init (GstWSinc * filter) +{ + filter->sinkpad = gst_pad_new_from_template (gst_filter_sink_factory (), "sink"); + gst_pad_set_chain_function (filter->sinkpad, gst_wsinc_chain); + gst_pad_set_connect_function (filter->sinkpad, gst_wsinc_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_wsinc_sink_connect (GstPad * pad, GstCaps * caps) +{ + int i = 0; + double sum = 0.0; + int len = 0; + GstWSinc *filter = GST_WSINC (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, + "wsinc: 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_wsinc_chain (GstPad * pad, GstBuffer * buf) +{ + GstWSinc *filter; + gfloat *src; + gfloat *input; + gint residue_samples; + gint input_samples; + gint total_samples; + int i, j; + + filter = GST_WSINC (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_wsinc_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec) +{ + GstWSinc *filter; + + /* it's not null if we got it, but it might not be ours */ + g_return_if_fail (GST_IS_WSINC (object)); + + filter = GST_WSINC (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_wsinc_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec) +{ + GstWSinc *filter; + + /* it's not null if we got it, but it might not be ours */ + g_return_if_fail (GST_IS_WSINC (object)); + + filter = GST_WSINC (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; + } +} + -- 2.7.4