1 /* GStreamer
2 * Copyright (C) 2013 David Schleef <ds@schleef.org>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 51 Franklin Street, Suite 500,
17 * Boston, MA 02110-1335, USA.
18 */
19 /**
20 * SECTION:element-gstaudiochannelmix
21 * @title: gstaudiochannelmix
22 *
23 * The audiochannelmix element mixes channels in stereo audio based on
24 * properties set on the element. The primary purpose is reconstruct
25 * equal left/right channels on an input stream that has audio in only
26 * one channel.
27 *
28 * ## Example launch line
29 * |[
30 * gst-launch-1.0 -v audiotestsrc ! audiochannelmix ! autoaudiosink
31 * ]|
32 *
33 */
34
35 #ifdef HAVE_CONFIG_H
36 #include "config.h"
37 #endif
38
39 #include <gst/gst.h>
40 #include <gst/audio/gstaudiofilter.h>
41 #include "gstaudiochannelmix.h"
42 #include <math.h>
43
44 GST_DEBUG_CATEGORY_STATIC (gst_audio_channel_mix_debug_category);
45 #define GST_CAT_DEFAULT gst_audio_channel_mix_debug_category
46
47 /* prototypes */
48
49
50 static void gst_audio_channel_mix_set_property (GObject * object,
51 guint property_id, const GValue * value, GParamSpec * pspec);
52 static void gst_audio_channel_mix_get_property (GObject * object,
53 guint property_id, GValue * value, GParamSpec * pspec);
54
55 static gboolean gst_audio_channel_mix_setup (GstAudioFilter * filter,
56 const GstAudioInfo * info);
57 static GstFlowReturn gst_audio_channel_mix_transform_ip (GstBaseTransform *
58 trans, GstBuffer * buf);
59
60 enum
61 {
62 PROP_0,
63 PROP_LEFT_TO_LEFT,
64 PROP_LEFT_TO_RIGHT,
65 PROP_RIGHT_TO_LEFT,
66 PROP_RIGHT_TO_RIGHT
67 };
68
69 /* pad templates */
70
71 static GstStaticPadTemplate gst_audio_channel_mix_src_template =
72 GST_STATIC_PAD_TEMPLATE ("src",
73 GST_PAD_SRC,
74 GST_PAD_ALWAYS,
75 GST_STATIC_CAPS ("audio/x-raw,format=S16LE,rate=[1,max],"
76 "channels=2,layout=interleaved")
77 );
78
79 static GstStaticPadTemplate gst_audio_channel_mix_sink_template =
80 GST_STATIC_PAD_TEMPLATE ("sink",
81 GST_PAD_SINK,
82 GST_PAD_ALWAYS,
83 GST_STATIC_CAPS ("audio/x-raw,format=S16LE,rate=[1,max],"
84 "channels=2,layout=interleaved")
85 );
86
87
88 /* class initialization */
89
90 G_DEFINE_TYPE_WITH_CODE (GstAudioChannelMix, gst_audio_channel_mix,
91 GST_TYPE_AUDIO_FILTER,
92 GST_DEBUG_CATEGORY_INIT (gst_audio_channel_mix_debug_category,
93 "audiochannelmix", 0, "debug category for audiochannelmix element"));
94
95 static void
gst_audio_channel_mix_class_init(GstAudioChannelMixClass * klass)96 gst_audio_channel_mix_class_init (GstAudioChannelMixClass * klass)
97 {
98 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
99 GstBaseTransformClass *base_transform_class =
100 GST_BASE_TRANSFORM_CLASS (klass);
101 GstAudioFilterClass *audio_filter_class = GST_AUDIO_FILTER_CLASS (klass);
102
103 /* Setting up pads and setting metadata should be moved to
104 base_class_init if you intend to subclass this class. */
105 gst_element_class_add_static_pad_template (GST_ELEMENT_CLASS (klass),
106 &gst_audio_channel_mix_src_template);
107 gst_element_class_add_static_pad_template (GST_ELEMENT_CLASS (klass),
108 &gst_audio_channel_mix_sink_template);
109
110 gst_element_class_set_static_metadata (GST_ELEMENT_CLASS (klass),
111 "Simple stereo audio mixer", "Audio/Mixer", "Mixes left/right channels "
112 "of stereo audio", "David Schleef <ds@schleef.org>");
113
114 gobject_class->set_property = gst_audio_channel_mix_set_property;
115 gobject_class->get_property = gst_audio_channel_mix_get_property;
116 audio_filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_channel_mix_setup);
117 base_transform_class->transform_ip =
118 GST_DEBUG_FUNCPTR (gst_audio_channel_mix_transform_ip);
119
120 g_object_class_install_property (gobject_class, PROP_LEFT_TO_LEFT,
121 g_param_spec_double ("left-to-left", "Left to Left",
122 "Left channel to left channel gain",
123 -G_MAXDOUBLE, G_MAXDOUBLE, 1.0,
124 GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
125
126 g_object_class_install_property (gobject_class, PROP_LEFT_TO_RIGHT,
127 g_param_spec_double ("left-to-right", "Left to Right",
128 "Left channel to right channel gain",
129 -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
130 GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
131
132 g_object_class_install_property (gobject_class, PROP_RIGHT_TO_LEFT,
133 g_param_spec_double ("right-to-left", "Right to Left",
134 "Right channel to left channel gain",
135 -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
136 GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
137
138 g_object_class_install_property (gobject_class, PROP_RIGHT_TO_RIGHT,
139 g_param_spec_double ("right-to-right", "Right to Right",
140 "Right channel to right channel gain",
141 -G_MAXDOUBLE, G_MAXDOUBLE, 1.0,
142 GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
143 }
144
145 static void
gst_audio_channel_mix_init(GstAudioChannelMix * audiochannelmix)146 gst_audio_channel_mix_init (GstAudioChannelMix * audiochannelmix)
147 {
148 audiochannelmix->left_to_left = 1.0;
149 audiochannelmix->left_to_right = 0.0;
150 audiochannelmix->right_to_left = 0.0;
151 audiochannelmix->right_to_right = 1.0;
152 }
153
154 void
gst_audio_channel_mix_set_property(GObject * object,guint property_id,const GValue * value,GParamSpec * pspec)155 gst_audio_channel_mix_set_property (GObject * object, guint property_id,
156 const GValue * value, GParamSpec * pspec)
157 {
158 GstAudioChannelMix *audiochannelmix = GST_AUDIO_CHANNEL_MIX (object);
159
160 GST_DEBUG_OBJECT (audiochannelmix, "set_property");
161
162 switch (property_id) {
163 case PROP_LEFT_TO_LEFT:
164 audiochannelmix->left_to_left = g_value_get_double (value);
165 break;
166 case PROP_LEFT_TO_RIGHT:
167 audiochannelmix->left_to_right = g_value_get_double (value);
168 break;
169 case PROP_RIGHT_TO_LEFT:
170 audiochannelmix->right_to_left = g_value_get_double (value);
171 break;
172 case PROP_RIGHT_TO_RIGHT:
173 audiochannelmix->right_to_right = g_value_get_double (value);
174 break;
175 default:
176 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
177 break;
178 }
179 }
180
181 void
gst_audio_channel_mix_get_property(GObject * object,guint property_id,GValue * value,GParamSpec * pspec)182 gst_audio_channel_mix_get_property (GObject * object, guint property_id,
183 GValue * value, GParamSpec * pspec)
184 {
185 GstAudioChannelMix *audiochannelmix = GST_AUDIO_CHANNEL_MIX (object);
186
187 GST_DEBUG_OBJECT (audiochannelmix, "get_property");
188
189 switch (property_id) {
190 case PROP_LEFT_TO_LEFT:
191 g_value_set_double (value, audiochannelmix->left_to_left);
192 break;
193 case PROP_LEFT_TO_RIGHT:
194 g_value_set_double (value, audiochannelmix->left_to_right);
195 break;
196 case PROP_RIGHT_TO_LEFT:
197 g_value_set_double (value, audiochannelmix->right_to_left);
198 break;
199 case PROP_RIGHT_TO_RIGHT:
200 g_value_set_double (value, audiochannelmix->right_to_right);
201 break;
202 default:
203 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
204 break;
205 }
206 }
207
208 static gboolean
gst_audio_channel_mix_setup(GstAudioFilter * filter,const GstAudioInfo * info)209 gst_audio_channel_mix_setup (GstAudioFilter * filter, const GstAudioInfo * info)
210 {
211 #ifndef GST_DISABLE_GST_DEBUG
212 GstAudioChannelMix *audiochannelmix = GST_AUDIO_CHANNEL_MIX (filter);
213
214 GST_DEBUG_OBJECT (audiochannelmix, "setup");
215 #endif
216
217 return TRUE;
218 }
219
220 static GstFlowReturn
gst_audio_channel_mix_transform_ip(GstBaseTransform * trans,GstBuffer * buf)221 gst_audio_channel_mix_transform_ip (GstBaseTransform * trans, GstBuffer * buf)
222 {
223 GstAudioChannelMix *audiochannelmix = GST_AUDIO_CHANNEL_MIX (trans);
224 int n;
225 GstMapInfo map;
226 int i;
227 double ll = audiochannelmix->left_to_left;
228 double lr = audiochannelmix->left_to_right;
229 double rl = audiochannelmix->right_to_left;
230 double rr = audiochannelmix->right_to_right;
231 int l, r;
232 gint16 *data;
233
234 GST_DEBUG_OBJECT (audiochannelmix, "transform_ip");
235
236 gst_buffer_map (buf, &map, GST_MAP_WRITE | GST_MAP_READ);
237
238 n = gst_buffer_get_size (buf) >> 2;
239 data = (gint16 *) map.data;
240 for (i = 0; i < n; i++) {
241 l = data[2 * i + 0];
242 r = data[2 * i + 1];
243 data[2 * i + 0] = CLAMP (rint (ll * l + rl * r), -32768, 32767);
244 data[2 * i + 1] = CLAMP (rint (lr * l + rr * r), -32768, 32767);
245 }
246
247 gst_buffer_unmap (buf, &map);
248
249 return GST_FLOW_OK;
250 }
251