1 /* 

     2  * GStreamer

     3  * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>

     4  *

     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.

     9  *

    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.

    14  *

    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.

    19  * 

    20  */

    21 

    22 /**

    23  * SECTION:element-audioiirfilter

    24  *

    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

    27  * should be used.

    28  *

    29  * The filter coefficients describe the numerator and denominator of the

    30  * transfer function.

    31  *

    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.

    35  *

    36  * <refsect2>

    37  * <title>Example application</title>

    38  * |[

    39  * <xi:include xmlns:xi="http://www.w3.org/2003/XInclude" parse="text" href="../../../../tests/examples/audiofx/iirfilter-example.c" />

    40  * ]|

    41  * </refsect2>

    42  */

    43 

    44 #ifdef HAVE_CONFIG_H

    45 #include "config.h"

    46 #endif

    47 

    48 #include <string.h>

    49 #include <math.h>

    50 #include <gst/gst.h>

    51 #include <gst/audio/gstaudiofilter.h>

    52 #include <gst/controller/gstcontroller.h>

    53 

    54 #include "audioiirfilter.h"

    55 

    56 #define GST_CAT_DEFAULT gst_audio_iir_filter_debug

    57 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

    58 

    59 enum

    60 {

    61   SIGNAL_RATE_CHANGED,

    62   LAST_SIGNAL

    63 };

    64 

    65 enum

    66 {

    67   PROP_0,

    68   PROP_A,

    69   PROP_B

    70 };

    71 

    72 static guint gst_audio_iir_filter_signals[LAST_SIGNAL] = { 0, };

    73 

    74 #define DEBUG_INIT(bla) \

    75   GST_DEBUG_CATEGORY_INIT (gst_audio_iir_filter_debug, "audioiirfilter", 0, \

    76       "Generic audio IIR filter plugin");

    77 

    78 GST_BOILERPLATE_FULL (GstAudioIIRFilter, gst_audio_iir_filter, GstAudioFilter,

    79     GST_TYPE_AUDIO_FX_BASE_IIR_FILTER, DEBUG_INIT);

    80 

    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);

    86 

    87 static gboolean gst_audio_iir_filter_setup (GstAudioFilter * base,

    88     GstRingBufferSpec * format);

    89 

    90 /* Element class */

    91 static void

    92 gst_audio_iir_filter_base_init (gpointer g_class)

    93 {

    94   GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

    95 

    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>");

   100 }

   101 

   102 static void

   103 gst_audio_iir_filter_class_init (GstAudioIIRFilterClass * klass)

   104 {

   105   GObjectClass *gobject_class = (GObjectClass *) klass;

   106   GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;

   107 

   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;

   111 

   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));

   126 

   127   filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_iir_filter_setup);

   128 

   129   /**

   130    * GstAudioIIRFilter::rate-changed:

   131    * @filter: the filter on which the signal is emitted

   132    * @rate: the new sampling rate

   133    *

   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.

   137    */

   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);

   142 }

   143 

   144 static void

   145 gst_audio_iir_filter_update_coefficients (GstAudioIIRFilter * self,

   146     GValueArray * va, GValueArray * vb)

   147 {

   148   gdouble *a = NULL, *b = NULL;

   149   guint i;

   150 

   151   if (va) {

   152     if (self->a)

   153       g_value_array_free (self->a);

   154 

   155     self->a = va;

   156   }

   157   if (vb) {

   158     if (self->b)

   159       g_value_array_free (self->b);

   160 

   161     self->b = vb;

   162   }

   163 

   164   if (self->a && self->a->n_values > 0)

   165     a = g_new (gdouble, self->a->n_values);

   166   if (self->b && self->b->n_values > 0)

   167     b = g_new (gdouble, self->b->n_values);

   168 

   169   if (self->a) {

   170     for (i = 0; i < self->a->n_values; i++) {

   171       GValue *v = g_value_array_get_nth (self->a, i);

   172       a[i] = g_value_get_double (v);

   173     }

   174   }

   175 

   176   if (self->b) {

   177     for (i = 0; i < self->b->n_values; i++) {

   178       GValue *v = g_value_array_get_nth (self->b, i);

   179       b[i] = g_value_get_double (v);

   180     }

   181   }

   182 

   183   gst_audio_fx_base_iir_filter_set_coefficients (GST_AUDIO_FX_BASE_IIR_FILTER

   184       (self), a, (self->a) ? self->a->n_values : 0, b,

   185       (self->b) ? self->b->n_values : 0);

   186 }

   187 

   188 static void

   189 gst_audio_iir_filter_init (GstAudioIIRFilter * self,

   190     GstAudioIIRFilterClass * g_class)

   191 {

   192   GValue v = { 0, };

   193   GValueArray *a, *b;

   194 

   195   a = g_value_array_new (1);

   196 

   197   g_value_init (&v, G_TYPE_DOUBLE);

   198   g_value_set_double (&v, 1.0);

   199   g_value_array_append (a, &v);

   200   g_value_unset (&v);

   201 

   202   b = NULL;

   203   gst_audio_iir_filter_update_coefficients (self, a, b);

   204 

   205   self->lock = g_mutex_new ();

   206 }

   207 

   208 /* GstAudioFilter vmethod implementations */

   209 

   210 /* get notified of caps and plug in the correct process function */

   211 static gboolean

   212 gst_audio_iir_filter_setup (GstAudioFilter * base, GstRingBufferSpec * format)

   213 {

   214   GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (base);

   215 

   216   if (self->rate != format->rate) {

   217     g_signal_emit (G_OBJECT (self),

   218         gst_audio_iir_filter_signals[SIGNAL_RATE_CHANGED], 0, format->rate);

   219     self->rate = format->rate;

   220   }

   221 

   222   return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);

   223 }

   224 

   225 static void

   226 gst_audio_iir_filter_finalize (GObject * object)

   227 {

   228   GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);

   229 

   230   g_mutex_free (self->lock);

   231   self->lock = NULL;

   232 

   233   if (self->a)

   234     g_value_array_free (self->a);

   235   self->a = NULL;

   236   if (self->b)

   237     g_value_array_free (self->b);

   238   self->b = NULL;

   239 

   240   G_OBJECT_CLASS (parent_class)->finalize (object);

   241 }

   242 

   243 static void

   244 gst_audio_iir_filter_set_property (GObject * object, guint prop_id,

   245     const GValue * value, GParamSpec * pspec)

   246 {

   247   GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);

   248 

   249   g_return_if_fail (GST_IS_AUDIO_IIR_FILTER (self));

   250 

   251   switch (prop_id) {

   252     case PROP_A:

   253       g_mutex_lock (self->lock);

   254       gst_audio_iir_filter_update_coefficients (self, g_value_dup_boxed (value),

   255           NULL);

   256       g_mutex_unlock (self->lock);

   257       break;

   258     case PROP_B:

   259       g_mutex_lock (self->lock);

   260       gst_audio_iir_filter_update_coefficients (self, NULL,

   261           g_value_dup_boxed (value));

   262       g_mutex_unlock (self->lock);

   263       break;

   264     default:

   265       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

   266       break;

   267   }

   268 }

   269 

   270 static void

   271 gst_audio_iir_filter_get_property (GObject * object, guint prop_id,

   272     GValue * value, GParamSpec * pspec)

   273 {

   274   GstAudioIIRFilter *self = GST_AUDIO_IIR_FILTER (object);

   275 

   276   switch (prop_id) {

   277     case PROP_A:

   278       g_value_set_boxed (value, self->a);

   279       break;

   280     case PROP_B:

   281       g_value_set_boxed (value, self->b);

   282       break;

   283     default:

   284       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

   285       break;

   286   }

   287 }