3 * Copyright (C) 2008 Wim Taymans <wim.taymans@gmail.com>
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.
22 * SECTION:element-audiokaraoke
24 * Remove the voice from audio by filtering the center channel.
25 * This plugin is useful for karaoke applications.
28 * <title>Example launch line</title>
30 * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audiokaraoke ! audioconvert ! alsasink
42 #include <gst/base/gstbasetransform.h>
43 #include <gst/audio/audio.h>
44 #include <gst/audio/gstaudiofilter.h>
46 #include "audiokaraoke.h"
48 #define GST_CAT_DEFAULT gst_audio_karaoke_debug
49 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
51 /* Filter signals and args */
58 #define DEFAULT_LEVEL 1.0
59 #define DEFAULT_MONO_LEVEL 1.0
60 #define DEFAULT_FILTER_BAND 220.0
61 #define DEFAULT_FILTER_WIDTH 100.0
73 #define ALLOWED_CAPS \
75 " format=(string){"GST_AUDIO_NE(S16)","GST_AUDIO_NE(F32)"}," \
76 " rate=(int)[1,MAX]," \
77 " channels=(int)[1,MAX]"
79 G_DEFINE_TYPE (GstAudioKaraoke, gst_audio_karaoke, GST_TYPE_AUDIO_FILTER);
81 static void gst_audio_karaoke_set_property (GObject * object, guint prop_id,
82 const GValue * value, GParamSpec * pspec);
83 static void gst_audio_karaoke_get_property (GObject * object, guint prop_id,
84 GValue * value, GParamSpec * pspec);
86 static gboolean gst_audio_karaoke_setup (GstAudioFilter * filter,
87 const GstAudioInfo * info);
88 static GstFlowReturn gst_audio_karaoke_transform_ip (GstBaseTransform * base,
91 static void gst_audio_karaoke_transform_int (GstAudioKaraoke * filter,
92 gint16 * data, guint num_samples);
93 static void gst_audio_karaoke_transform_float (GstAudioKaraoke * filter,
94 gfloat * data, guint num_samples);
96 /* GObject vmethod implementations */
99 gst_audio_karaoke_class_init (GstAudioKaraokeClass * klass)
101 GObjectClass *gobject_class;
102 GstElementClass *gstelement_class;
105 GST_DEBUG_CATEGORY_INIT (gst_audio_karaoke_debug, "audiokaraoke", 0,
106 "audiokaraoke element");
108 gobject_class = (GObjectClass *) klass;
109 gstelement_class = (GstElementClass *) klass;
111 gobject_class->set_property = gst_audio_karaoke_set_property;
112 gobject_class->get_property = gst_audio_karaoke_get_property;
114 g_object_class_install_property (gobject_class, PROP_LEVEL,
115 g_param_spec_float ("level", "Level",
116 "Level of the effect (1.0 = full)", 0.0, 1.0, DEFAULT_LEVEL,
117 G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
119 g_object_class_install_property (gobject_class, PROP_MONO_LEVEL,
120 g_param_spec_float ("mono-level", "Mono Level",
121 "Level of the mono channel (1.0 = full)", 0.0, 1.0, DEFAULT_LEVEL,
122 G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
124 g_object_class_install_property (gobject_class, PROP_FILTER_BAND,
125 g_param_spec_float ("filter-band", "Filter Band",
126 "The Frequency band of the filter", 0.0, 441.0, DEFAULT_FILTER_BAND,
127 G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
129 g_object_class_install_property (gobject_class, PROP_FILTER_WIDTH,
130 g_param_spec_float ("filter-width", "Filter Width",
131 "The Frequency width of the filter", 0.0, 100.0, DEFAULT_FILTER_WIDTH,
132 G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
134 gst_element_class_set_details_simple (gstelement_class, "AudioKaraoke",
135 "Filter/Effect/Audio",
136 "Removes voice from sound", "Wim Taymans <wim.taymans@gmail.com>");
138 caps = gst_caps_from_string (ALLOWED_CAPS);
139 gst_audio_filter_class_add_pad_templates (GST_AUDIO_FILTER_CLASS (klass),
141 gst_caps_unref (caps);
143 GST_AUDIO_FILTER_CLASS (klass)->setup =
144 GST_DEBUG_FUNCPTR (gst_audio_karaoke_setup);
145 GST_BASE_TRANSFORM_CLASS (klass)->transform_ip =
146 GST_DEBUG_FUNCPTR (gst_audio_karaoke_transform_ip);
150 gst_audio_karaoke_init (GstAudioKaraoke * filter)
152 gst_base_transform_set_in_place (GST_BASE_TRANSFORM (filter), TRUE);
153 gst_base_transform_set_gap_aware (GST_BASE_TRANSFORM (filter), TRUE);
155 filter->level = DEFAULT_LEVEL;
156 filter->mono_level = DEFAULT_MONO_LEVEL;
157 filter->filter_band = DEFAULT_FILTER_BAND;
158 filter->filter_width = DEFAULT_FILTER_WIDTH;
162 update_filter (GstAudioKaraoke * filter)
167 rate = GST_AUDIO_FILTER_RATE (filter);
171 C = exp (-2 * G_PI * filter->filter_width / rate);
172 B = -4 * C / (1 + C) * cos (2 * G_PI * filter->filter_band / rate);
173 A = sqrt (1 - B * B / (4 * C)) * (1 - C);
183 gst_audio_karaoke_set_property (GObject * object, guint prop_id,
184 const GValue * value, GParamSpec * pspec)
186 GstAudioKaraoke *filter;
188 filter = GST_AUDIO_KARAOKE (object);
192 filter->level = g_value_get_float (value);
194 case PROP_MONO_LEVEL:
195 filter->mono_level = g_value_get_float (value);
197 case PROP_FILTER_BAND:
198 filter->filter_band = g_value_get_float (value);
199 update_filter (filter);
201 case PROP_FILTER_WIDTH:
202 filter->filter_width = g_value_get_float (value);
203 update_filter (filter);
206 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
212 gst_audio_karaoke_get_property (GObject * object, guint prop_id,
213 GValue * value, GParamSpec * pspec)
215 GstAudioKaraoke *filter;
217 filter = GST_AUDIO_KARAOKE (object);
221 g_value_set_float (value, filter->level);
223 case PROP_MONO_LEVEL:
224 g_value_set_float (value, filter->mono_level);
226 case PROP_FILTER_BAND:
227 g_value_set_float (value, filter->filter_band);
229 case PROP_FILTER_WIDTH:
230 g_value_set_float (value, filter->filter_width);
233 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
238 /* GstAudioFilter vmethod implementations */
241 gst_audio_karaoke_setup (GstAudioFilter * base, const GstAudioInfo * info)
243 GstAudioKaraoke *filter = GST_AUDIO_KARAOKE (base);
246 switch (GST_AUDIO_INFO_FORMAT (info)) {
247 case GST_AUDIO_FORMAT_S16:
248 filter->process = (GstAudioKaraokeProcessFunc)
249 gst_audio_karaoke_transform_int;
251 case GST_AUDIO_FORMAT_F32:
252 filter->process = (GstAudioKaraokeProcessFunc)
253 gst_audio_karaoke_transform_float;
259 update_filter (filter);
265 gst_audio_karaoke_transform_int (GstAudioKaraoke * filter,
266 gint16 * data, guint num_samples)
273 channels = GST_AUDIO_FILTER_CHANNELS (filter);
274 level = filter->level * 256;
276 for (i = 0; i < num_samples; i += channels) {
277 /* get left and right inputs */
282 y = (filter->A * x - filter->B * filter->y1) - filter->C * filter->y2;
283 filter->y2 = filter->y1;
285 /* filter mono signal */
286 o = (int) (y * filter->mono_level);
287 o = CLAMP (o, G_MININT16, G_MAXINT16);
288 o = (o * level) >> 8;
289 /* now cut the center */
290 x = l - ((r * level) >> 8) + o;
291 r = r - ((l * level) >> 8) + o;
292 data[i] = CLAMP (x, G_MININT16, G_MAXINT16);
293 data[i + 1] = CLAMP (r, G_MININT16, G_MAXINT16);
298 gst_audio_karaoke_transform_float (GstAudioKaraoke * filter,
299 gfloat * data, guint num_samples)
306 channels = GST_AUDIO_FILTER_CHANNELS (filter);
308 for (i = 0; i < num_samples; i += channels) {
309 /* get left and right inputs */
313 y = (filter->A * ((l + r) / 2.0) - filter->B * filter->y1) -
314 filter->C * filter->y2;
315 filter->y2 = filter->y1;
317 /* filter mono signal */
318 o = y * filter->mono_level * filter->level;
319 /* now cut the center */
320 data[i] = l - (r * filter->level) + o;
321 data[i + 1] = r - (l * filter->level) + o;
325 /* GstBaseTransform vmethod implementations */
327 gst_audio_karaoke_transform_ip (GstBaseTransform * base, GstBuffer * buf)
329 GstAudioKaraoke *filter = GST_AUDIO_KARAOKE (base);
331 GstClockTime timestamp, stream_time;
335 timestamp = GST_BUFFER_TIMESTAMP (buf);
337 gst_segment_to_stream_time (&base->segment, GST_FORMAT_TIME, timestamp);
339 GST_DEBUG_OBJECT (filter, "sync to %" GST_TIME_FORMAT,
340 GST_TIME_ARGS (timestamp));
342 if (GST_CLOCK_TIME_IS_VALID (stream_time))
343 gst_object_sync_values (GST_OBJECT (filter), stream_time);
345 if (gst_base_transform_is_passthrough (base) ||
346 G_UNLIKELY (GST_BUFFER_FLAG_IS_SET (buf, GST_BUFFER_FLAG_GAP)))
349 data = gst_buffer_map (buf, &size, NULL, GST_MAP_READWRITE);
350 num_samples = size / GST_AUDIO_FILTER_BPS (filter);
352 filter->process (filter, data, num_samples);
354 gst_buffer_unmap (buf, data, size);