1 /* GStreamer IIR equalizer
2  * Copyright (C) <2004> Benjamin Otte <otte@gnome.org>
3  *               <2007> Stefan Kost <ensonic@users.sf.net>
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., 51 Franklin St, Fifth Floor,
18  * Boston, MA 02110-1301, USA.
19  */
20 
21 #ifndef __GST_IIR_EQUALIZER__
22 #define __GST_IIR_EQUALIZER__
23 
24 #include <gst/audio/gstaudiofilter.h>
25 
26 typedef struct _GstIirEqualizer GstIirEqualizer;
27 typedef struct _GstIirEqualizerClass GstIirEqualizerClass;
28 typedef struct _GstIirEqualizerBand GstIirEqualizerBand;
29 
30 #define GST_TYPE_IIR_EQUALIZER \
31   (gst_iir_equalizer_get_type())
32 #define GST_IIR_EQUALIZER(obj) \
33   (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_IIR_EQUALIZER,GstIirEqualizer))
34 #define GST_IIR_EQUALIZER_CLASS(klass) \
35   (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_IIR_EQUALIZER,GstIirEqualizerClass))
36 #define GST_IS_IIR_EQUALIZER(obj) \
37   (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_IIR_EQUALIZER))
38 #define GST_IS_IIR_EQUALIZER_CLASS(klass) \
39   (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_IIR_EQUALIZER))
40 
41 #define LOWEST_FREQ (20.0)
42 #define HIGHEST_FREQ (20000.0)
43 
44 typedef void (*ProcessFunc) (GstIirEqualizer * eq, guint8 * data, guint size,
45     guint channels);
46 
47 struct _GstIirEqualizer
48 {
49   GstAudioFilter audiofilter;
50 
51   /*< private >*/
52 
53   GMutex bands_lock;
54   GstIirEqualizerBand **bands;
55 
56   /* properties */
57   guint freq_band_count;
58   /* for each band and channel */
59   gpointer history;
60   guint history_size;
61 
62   gboolean need_new_coefficients;
63 
64   ProcessFunc process;
65 };
66 
67 struct _GstIirEqualizerClass
68 {
69   GstAudioFilterClass audiofilter_class;
70 };
71 
72 extern void gst_iir_equalizer_compute_frequencies (GstIirEqualizer * equ, guint new_count);
73 
74 extern GType gst_iir_equalizer_get_type(void);
75 
76 #endif /* __GST_IIR_EQUALIZER__ */
77