Remove a cast that is not needed.
[asterisk/asterisk.git] / bridges / bridge_softmix.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2007, Digium, Inc.
5  *
6  * Joshua Colp <jcolp@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18
19 /*! \file
20  *
21  * \brief Multi-party software based channel mixing
22  *
23  * \author Joshua Colp <jcolp@digium.com>
24  *
25  * \ingroup bridges
26  *
27  * \todo This bridge operates in 8 kHz mode unless a define is uncommented.
28  * This needs to be improved so the bridge moves between the dominant codec as needed depending
29  * on channels present in the bridge and transcoding capabilities.
30  */
31
32 #include "asterisk.h"
33
34 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
35
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <sys/time.h>
40 #include <signal.h>
41 #include <errno.h>
42 #include <unistd.h>
43
44 #include "asterisk/module.h"
45 #include "asterisk/channel.h"
46 #include "asterisk/bridging.h"
47 #include "asterisk/bridging_technology.h"
48 #include "asterisk/frame.h"
49 #include "asterisk/options.h"
50 #include "asterisk/logger.h"
51 #include "asterisk/slinfactory.h"
52 #include "asterisk/astobj2.h"
53 #include "asterisk/timing.h"
54
55 /*! \brief Interval at which mixing will take place. Valid options are 10, 20, and 40. */
56 #define SOFTMIX_INTERVAL 20
57
58 /*! \brief Size of the buffer used for sample manipulation */
59 #define SOFTMIX_DATALEN (160 * (SOFTMIX_INTERVAL / 10))
60
61 /*! \brief Number of samples we are dealing with */
62 #define SOFTMIX_SAMPLES (SOFTMIX_DATALEN / 2)
63
64 /*! \brief Define used to turn on 16 kHz audio support */
65 /* #define SOFTMIX_16_SUPPORT */
66
67 /*! \brief Structure which contains per-channel mixing information */
68 struct softmix_channel {
69         /*! Lock to protect this structure */
70         ast_mutex_t lock;
71         /*! Factory which contains audio read in from the channel */
72         struct ast_slinfactory factory;
73         /*! Frame that contains mixed audio to be written out to the channel */
74         struct ast_frame frame;
75         /*! Bit used to indicate that the channel provided audio for this mixing interval */
76         int have_audio:1;
77         /*! Bit used to indicate that a frame is available to be written out to the channel */
78         int have_frame:1;
79         /*! Buffer containing final mixed audio from all sources */
80         short final_buf[SOFTMIX_DATALEN];
81         /*! Buffer containing only the audio from the channel */
82         short our_buf[SOFTMIX_DATALEN];
83 };
84
85 /*! \brief Function called when a bridge is created */
86 static int softmix_bridge_create(struct ast_bridge *bridge)
87 {
88         int timingfd;
89
90         if ((timingfd = ast_timer_open()) < 0) {
91                 return -1;
92         }
93
94         bridge->bridge_pvt = (void*)(unsigned long)timingfd;
95
96         return 0;
97 }
98
99 /*! \brief Function called when a channel is joined into the bridge */
100 static int softmix_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
101 {
102         struct softmix_channel *sc = NULL;
103
104         /* Create a new softmix_channel structure and allocate various things on it */
105         if (!(sc = ast_calloc(1, sizeof(*sc)))) {
106                 return -1;
107         }
108
109         /* Can't forget the lock */
110         ast_mutex_init(&sc->lock);
111
112         /* Setup smoother */
113         ast_slinfactory_init(&sc->factory);
114
115         /* Setup frame parameters */
116         sc->frame.frametype = AST_FRAME_VOICE;
117 #ifdef SOFTMIX_16_SUPPORT
118         sc->frame.subclass = AST_FORMAT_SLINEAR16;
119 #else
120         sc->frame.subclass = AST_FORMAT_SLINEAR;
121 #endif
122         sc->frame.data.ptr = sc->final_buf;
123         sc->frame.datalen = SOFTMIX_DATALEN;
124         sc->frame.samples = SOFTMIX_SAMPLES;
125
126         /* Can't forget to record our pvt structure within the bridged channel structure */
127         bridge_channel->bridge_pvt = sc;
128
129         return 0;
130 }
131
132 /*! \brief Function called when a channel leaves the bridge */
133 static int softmix_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
134 {
135         struct softmix_channel *sc = bridge_channel->bridge_pvt;
136
137         /* Drop mutex lock */
138         ast_mutex_destroy(&sc->lock);
139
140         /* Drop the factory */
141         ast_slinfactory_destroy(&sc->factory);
142
143         /* Eep! drop ourselves */
144         ast_free(sc);
145
146         return 0;
147 }
148
149 /*! \brief Function called when a channel writes a frame into the bridge */
150 static enum ast_bridge_write_result softmix_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
151 {
152         struct softmix_channel *sc = bridge_channel->bridge_pvt;
153
154         /* Only accept audio frames, all others are unsupported */
155         if (frame->frametype != AST_FRAME_VOICE) {
156                 return AST_BRIDGE_WRITE_UNSUPPORTED;
157         }
158
159         ast_mutex_lock(&sc->lock);
160
161         /* If a frame was provided add it to the smoother */
162 #ifdef SOFTMIX_16_SUPPORT
163         if (frame->frametype == AST_FRAME_VOICE && frame->subclass == AST_FORMAT_SLINEAR16) {
164 #else
165         if (frame->frametype == AST_FRAME_VOICE && frame->subclass == AST_FORMAT_SLINEAR) {
166 #endif
167                 ast_slinfactory_feed(&sc->factory, frame);
168         }
169
170         /* If a frame is ready to be written out, do so */
171         if (sc->have_frame) {
172                 ast_write(bridge_channel->chan, &sc->frame);
173                 sc->have_frame = 0;
174         }
175
176         /* Alllll done */
177         ast_mutex_unlock(&sc->lock);
178
179         return AST_BRIDGE_WRITE_SUCCESS;
180 }
181
182 /*! \brief Function called when the channel's thread is poked */
183 static int softmix_bridge_poke(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
184 {
185         struct softmix_channel *sc = bridge_channel->bridge_pvt;
186
187         ast_mutex_lock(&sc->lock);
188
189         if (sc->have_frame) {
190                 ast_write(bridge_channel->chan, &sc->frame);
191                 sc->have_frame = 0;
192         }
193
194         ast_mutex_unlock(&sc->lock);
195
196         return 0;
197 }
198
199 /*! \brief Function which acts as the mixing thread */
200 static int softmix_bridge_thread(struct ast_bridge *bridge)
201 {
202         int timingfd = (unsigned long)bridge->bridge_pvt;
203
204         ast_timer_set_rate(timingfd, (1000 / SOFTMIX_INTERVAL));
205
206         while (!bridge->stop && !bridge->refresh && bridge->array_num) {
207                 struct ast_bridge_channel *bridge_channel = NULL;
208                 short buf[SOFTMIX_DATALEN] = {0, };
209                 int timeout = -1;
210
211                 /* Go through pulling audio from each factory that has it available */
212                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
213                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
214
215                         ast_mutex_lock(&sc->lock);
216
217                         /* Try to get audio from the factory if available */
218                         if (ast_slinfactory_available(&sc->factory) >= SOFTMIX_SAMPLES && ast_slinfactory_read(&sc->factory, sc->our_buf, SOFTMIX_SAMPLES)) {
219                                 short *data1, *data2;
220                                 int i;
221
222                                 /* Put into the local final buffer */
223                                 for (i = 0, data1 = buf, data2 = sc->our_buf; i < SOFTMIX_DATALEN; i++, data1++, data2++)
224                                         ast_slinear_saturated_add(data1, data2);
225                                 /* Yay we have our own audio */
226                                 sc->have_audio = 1;
227                         } else {
228                                 /* Awww we don't have audio ;( */
229                                 sc->have_audio = 0;
230                         }
231                         ast_mutex_unlock(&sc->lock);
232                 }
233
234                 /* Next step go through removing the channel's own audio and creating a good frame... */
235                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
236                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
237                         int i = 0;
238
239                         /* Copy from local final buffer to our final buffer */
240                         memcpy(sc->final_buf, buf, sizeof(sc->final_buf));
241
242                         /* If we provided audio then take it out */
243                         if (sc->have_audio) {
244                                 for (i = 0; i < SOFTMIX_DATALEN; i++) {
245                                         ast_slinear_saturated_subtract(&sc->final_buf[i], &sc->our_buf[i]);
246                                 }
247                         }
248
249                         /* The frame is now ready for use... */
250                         sc->have_frame = 1;
251
252                         /* Poke bridged channel thread just in case */
253                         pthread_kill(bridge_channel->thread, SIGURG);
254                 }
255
256                 ao2_unlock(bridge);
257
258                 /* Wait for the timing source to tell us to wake up and get things done */
259                 ast_waitfor_n_fd(&timingfd, 1, &timeout, NULL);
260
261                 ast_timer_ack(timingfd, 1);
262
263                 ao2_lock(bridge);
264         }
265
266         ast_timer_close(timingfd);
267
268         return 0;
269 }
270
271 static struct ast_bridge_technology softmix_bridge = {
272         .name = "softmix",
273         .capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX | AST_BRIDGE_CAPABILITY_THREAD | AST_BRIDGE_CAPABILITY_MULTITHREADED,
274         .preference = AST_BRIDGE_PREFERENCE_LOW,
275 #ifdef SOFTMIX_16_SUPPORT
276         .formats = AST_FORMAT_SLINEAR16,
277 #else
278         .formats = AST_FORMAT_SLINEAR,
279 #endif
280         .create = softmix_bridge_create,
281         .join = softmix_bridge_join,
282         .leave = softmix_bridge_leave,
283         .write = softmix_bridge_write,
284         .thread = softmix_bridge_thread,
285         .poke = softmix_bridge_poke,
286 };
287
288 static int unload_module(void)
289 {
290         return ast_bridge_technology_unregister(&softmix_bridge);
291 }
292
293 static int load_module(void)
294 {
295         return ast_bridge_technology_register(&softmix_bridge);
296 }
297
298 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multi-party software based channel mixing");