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 DEBUG_INIT(bla) \
75 GST_DEBUG_CATEGORY_INIT (gst_audio_iir_filter_debug, "audioiirfilter", 0, \
76 "Generic audio IIR filter plugin");
78 GST_BOILERPLATE_FULL (GstAudioIIRFilter, gst_audio_iir_filter, GstAudioFilter,
79 GST_TYPE_AUDIO_FX_BASE_IIR_FILTER, DEBUG_INIT);
81 static void gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
82 const GValue * value, GParamSpec * pspec);
83 static void gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
84 GValue * value, GParamSpec * pspec);
85 static void gst_audio_iir_filter_finalize (GObject * object);
87 static gboolean gst_audio_iir_filter_setup (GstAudioFilter * base,
88 GstRingBufferSpec * format);
92 gst_audio_iir_filter_base_init (gpointer g_class)
94 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
96 gst_element_class_set_details_simple (element_class,
97 "Audio IIR filter", "Filter/Effect/Audio",
98 "Generic audio IIR filter with custom filter kernel",
99 "Sebastian Dröge <sebastian.droege@collabora.co.uk>");
103 gst_audio_iir_filter_class_init (GstAudioIIRFilterClass * klass)
105 GObjectClass *gobject_class = (GObjectClass *) klass;
106 GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
108 gobject_class->set_property = gst_audio_iir_filter_set_property;
109 gobject_class->get_property = gst_audio_iir_filter_get_property;
110 gobject_class->finalize = gst_audio_iir_filter_finalize;
112 g_object_class_install_property (gobject_class, PROP_A,
113 g_param_spec_value_array ("a", "A",
114 "Filter coefficients (numerator of transfer function)",
115 g_param_spec_double ("Coefficient", "Filter Coefficient",
116 "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
117 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
118 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
119 g_object_class_install_property (gobject_class, PROP_B,
120 g_param_spec_value_array ("b", "B",
121 "Filter coefficients (denominator of transfer function)",
122 g_param_spec_double ("Coefficient", "Filter Coefficient",
123 "Filter coefficient", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
124 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
125 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
127 filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_iir_filter_setup);
130 * GstAudioIIRFilter::rate-changed:
131 * @filter: the filter on which the signal is emitted
132 * @rate: the new sampling rate
134 * Will be emitted when the sampling rate changes. The callbacks
135 * will be called from the streaming thread and processing will
136 * stop until the event is handled.
138 gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED] =
139 g_signal_new ("rate-changed", G_TYPE_FROM_CLASS (klass),
140 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAudioIIRFilterClass, rate_changed),
141 NULL, NULL, gst_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
145 gst_audio_iir_filter_update_coefficients (GstAudioIIRFilter * self,
146 GValueArray * va, GValueArray * vb)
148 gdouble *a = NULL, *b = NULL;
153 g_value_array_free (self->a);
159 g_value_array_free (self->b);
164 if (self->a && self->a->n_values > 0) {
165 a = g_new (gdouble, self->a->n_values);
167 for (i = 0; i < self->a->n_values; i++) {
168 GValue *v = g_value_array_get_nth (self->a, i);
169 a[i] = g_value_get_double (v);
173 if (self->b && self->b->n_values > 0) {
174 b = g_new (gdouble, self->b->n_values);
175 for (i = 0; i < self->b->n_values; i++) {
176 GValue *v = g_value_array_get_nth (self->b, i);
177 b[i] = g_value_get_double (v);
181 gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER
182 (self), a, (self->a) ? self->a->n_values : 0, b,
183 (self->b) ? self->b->n_values : 0);
187 gst_audio_iir_filter_init (GstAudioIIRFilter * self,
188 GstAudioIIRFilterClass * g_class)
193 a = g_value_array_new (1);
195 g_value_init (&v, G_TYPE_DOUBLE);
196 g_value_set_double (&v, 1.0);
197 g_value_array_append (a, &v);
201 gst_audio_iir_filter_update_coefficients (self, a, b);
203 self->lock = g_mutex_new ();
206 /* GstAudioFilter vmethod implementations */
208 /* get notified of caps and plug in the correct process function */
210 gst_audio_iir_filter_setup (GstAudioFilter * base, GstRingBufferSpec * format)
212 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (base);
214 if (self->rate != format->rate) {
215 g_signal_emit (G_OBJECT (self),
216 gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED], 0, format->rate);
217 self->rate = format->rate;
220 return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
224 gst_audio_iir_filter_finalize (GObject * object)
226 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
228 g_mutex_free (self->lock);
232 g_value_array_free (self->a);
235 g_value_array_free (self->b);
238 G_OBJECT_CLASS (parent_class)->finalize (object);
242 gst_audio_iir_filter_set_property (GObject * object, guint prop_id,
243 const GValue * value, GParamSpec * pspec)
245 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
247 g_return_if_fail (GST_IS_AUDIO_IIR_FILTER (self));
251 g_mutex_lock (self->lock);
252 gst_audio_iir_filter_update_coefficients (self, g_value_dup_boxed (value),
254 g_mutex_unlock (self->lock);
257 g_mutex_lock (self->lock);
258 gst_audio_iir_filter_update_coefficients (self, NULL,
259 g_value_dup_boxed (value));
260 g_mutex_unlock (self->lock);
263 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
269 gst_audio_iir_filter_get_property (GObject * object, guint prop_id,
270 GValue * value, GParamSpec * pspec)
272 GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);
276 g_value_set_boxed (value, self->a);
279 g_value_set_boxed (value, self->b);
282 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);