3 * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
23 * SECTION:element-audioiirfilter
25 * audioiirfilter implements a generic audio <ulink url="http://en.wikipedia.org/wiki/Infinite_impulse_response">IIR filter</ulink>. Before usage the
26 * "a" and "b" properties have to be set to the filter coefficients that
29 * The filter coefficients describe the numerator and denominator of the
32 * To change the filter coefficients whenever the sampling rate changes the
33 * "rate-changed" signal can be used. This should be done for most
34 * IIR filters as they're depending on the sampling rate.
37 * <title>Example application</title>
39 * <xi:include xmlns:xi="http://www.w3.org/2003/XInclude" parse="text" href="../../../../tests/examples/audiofx/iirfilter-example.c" />
51 #include <gst/audio/gstaudiofilter.h>
52 #include <gst/controller/gstcontroller.h>
54 #include "audioiirfilter.h"
56 #define GST_CAT_DEFAULT gst_audio_iir_filter_debug
57 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
72 static guint gst_audio_iir_filter_signals[LAST_SIGNAL] = { 0, };
74 #define gst_audio_iir_filter_parent_class parent_class
75 G_DEFINE_TYPE (GstAudioIIRFilter, gst_audio_iir_filter,
76 GST_TYPE_AUDIO_FX_BASE_IIR_FILTER);
78 static void gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
79 const GValue * value, GParamSpec * pspec);
80 static void gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
81 GValue * value, GParamSpec * pspec);
82 static void gst_audio_iir_filter_finalize (GObject * object);
84 static gboolean gst_audio_iir_filter_setup (GstAudioFilter * base,
85 GstRingBufferSpec * format);
88 gst_audio_iir_filter_class_init (GstAudioIIRFilterClass * klass)
90 GObjectClass *gobject_class = (GObjectClass *) klass;
91 GstElementClass *gstelement_class = (GstElementClass *) klass;
92 GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
94 GST_DEBUG_CATEGORY_INIT (gst_audio_iir_filter_debug, "audioiirfilter", 0,
95 "Generic audio IIR filter plugin");
97 gobject_class->set_property = gst_audio_iir_filter_set_property;
98 gobject_class->get_property = gst_audio_iir_filter_get_property;
99 gobject_class->finalize = gst_audio_iir_filter_finalize;
101 g_object_class_install_property (gobject_class, PROP_A,
102 g_param_spec_value_array ("a", "A",
103 "Filter coefficients (numerator of transfer function)",
104 g_param_spec_double ("Coefficient", "Filter Coefficient",
105 "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
106 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
107 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
108 g_object_class_install_property (gobject_class, PROP_B,
109 g_param_spec_value_array ("b", "B",
110 "Filter coefficients (denominator of transfer function)",
111 g_param_spec_double ("Coefficient", "Filter Coefficient",
112 "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
113 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
114 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
116 filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_iir_filter_setup);
119 * GstAudioIIRFilter::rate-changed:
120 * @filter: the filter on which the signal is emitted
121 * @rate: the new sampling rate
123 * Will be emitted when the sampling rate changes. The callbacks
124 * will be called from the streaming thread and processing will
125 * stop until the event is handled.
127 gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED] =
128 g_signal_new ("rate-changed", G_TYPE_FROM_CLASS (klass),
129 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAudioIIRFilterClass, rate_changed),
130 NULL, NULL, gst_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
132 gst_element_class_set_details_simple (gstelement_class,
133 "Audio IIR filter", "Filter/Effect/Audio",
134 "Generic audio IIR filter with custom filter kernel",
135 "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
139 gst_audio_iir_filter_update_coefficients (GstAudioIIRFilter * self,
140 GValueArray * va, GValueArray * vb)
142 gdouble *a = NULL, *b = NULL;
147 g_value_array_free (self->a);
153 g_value_array_free (self->b);
158 if (self->a && self->a->n_values > 0) {
159 a = g_new (gdouble, self->a->n_values);
161 for (i = 0; i < self->a->n_values; i++) {
162 GValue *v = g_value_array_get_nth (self->a, i);
163 a[i] = g_value_get_double (v);
167 if (self->b && self->b->n_values > 0) {
168 b = g_new (gdouble, self->b->n_values);
169 for (i = 0; i < self->b->n_values; i++) {
170 GValue *v = g_value_array_get_nth (self->b, i);
171 b[i] = g_value_get_double (v);
175 gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
176 (self), a, (self->a) ? self->a->n_values : 0, b,
177 (self->b) ? self->b->n_values : 0);
181 gst_audio_iir_filter_init (GstAudioIIRFilter * self)
186 a = g_value_array_new (1);
188 g_value_init (&v, G_TYPE_DOUBLE);
189 g_value_set_double (&v, 1.0);
190 g_value_array_append (a, &v);
194 gst_audio_iir_filter_update_coefficients (self, a, b);
196 self->lock = g_mutex_new ();
199 /* GstAudioFilter vmethod implementations */
201 /* get notified of caps and plug in the correct process function */
203 gst_audio_iir_filter_setup (GstAudioFilter * base, GstRingBufferSpec * format)
205 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (base);
207 if (self->rate != format->rate) {
208 g_signal_emit (G_OBJECT (self),
209 gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED], 0, format->rate);
210 self->rate = format->rate;
213 return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
217 gst_audio_iir_filter_finalize (GObject * object)
219 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
221 g_mutex_free (self->lock);
225 g_value_array_free (self->a);
228 g_value_array_free (self->b);
231 G_OBJECT_CLASS (parent_class)->finalize (object);
235 gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
236 const GValue * value, GParamSpec * pspec)
238 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
240 g_return_if_fail (GST_IS_AUDIO_IIR_FILTER (self));
244 g_mutex_lock (self->lock);
245 gst_audio_iir_filter_update_coefficients (self, g_value_dup_boxed (value),
247 g_mutex_unlock (self->lock);
250 g_mutex_lock (self->lock);
251 gst_audio_iir_filter_update_coefficients (self, NULL,
252 g_value_dup_boxed (value));
253 g_mutex_unlock (self->lock);
256 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
262 gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
263 GValue * value, GParamSpec * pspec)
265 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
269 g_value_set_boxed (value, self->a);
272 g_value_set_boxed (value, self->b);
275 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);