Improve timing interface to remember which provider provided a timer
[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         struct ast_timer *timer;
89
90         if (!(timer = ast_timer_open())) {
91                 return -1;
92         }
93
94         bridge->bridge_pvt = timer;
95
96         return 0;
97 }
98
99 /*! \brief Function called when a bridge is destroyed */
100 static int softmix_bridge_destroy(struct ast_bridge *bridge)
101 {
102         ast_timer_close((struct ast_timer *) bridge->bridge_pvt);
103
104         return 0;
105 }
106
107 /*! \brief Function called when a channel is joined into the bridge */
108 static int softmix_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
109 {
110         struct softmix_channel *sc = NULL;
111
112         /* Create a new softmix_channel structure and allocate various things on it */
113         if (!(sc = ast_calloc(1, sizeof(*sc)))) {
114                 return -1;
115         }
116
117         /* Can't forget the lock */
118         ast_mutex_init(&sc->lock);
119
120         /* Setup smoother */
121         ast_slinfactory_init(&sc->factory);
122
123         /* Setup frame parameters */
124         sc->frame.frametype = AST_FRAME_VOICE;
125 #ifdef SOFTMIX_16_SUPPORT
126         sc->frame.subclass = AST_FORMAT_SLINEAR16;
127 #else
128         sc->frame.subclass = AST_FORMAT_SLINEAR;
129 #endif
130         sc->frame.data.ptr = sc->final_buf;
131         sc->frame.datalen = SOFTMIX_DATALEN;
132         sc->frame.samples = SOFTMIX_SAMPLES;
133
134         /* Can't forget to record our pvt structure within the bridged channel structure */
135         bridge_channel->bridge_pvt = sc;
136
137         return 0;
138 }
139
140 /*! \brief Function called when a channel leaves the bridge */
141 static int softmix_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
142 {
143         struct softmix_channel *sc = bridge_channel->bridge_pvt;
144
145         /* Drop mutex lock */
146         ast_mutex_destroy(&sc->lock);
147
148         /* Drop the factory */
149         ast_slinfactory_destroy(&sc->factory);
150
151         /* Eep! drop ourselves */
152         ast_free(sc);
153
154         return 0;
155 }
156
157 /*! \brief Function called when a channel writes a frame into the bridge */
158 static enum ast_bridge_write_result softmix_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
159 {
160         struct softmix_channel *sc = bridge_channel->bridge_pvt;
161
162         /* Only accept audio frames, all others are unsupported */
163         if (frame->frametype != AST_FRAME_VOICE) {
164                 return AST_BRIDGE_WRITE_UNSUPPORTED;
165         }
166
167         ast_mutex_lock(&sc->lock);
168
169         /* If a frame was provided add it to the smoother */
170 #ifdef SOFTMIX_16_SUPPORT
171         if (frame->frametype == AST_FRAME_VOICE && frame->subclass == AST_FORMAT_SLINEAR16) {
172 #else
173         if (frame->frametype == AST_FRAME_VOICE && frame->subclass == AST_FORMAT_SLINEAR) {
174 #endif
175                 ast_slinfactory_feed(&sc->factory, frame);
176         }
177
178         /* If a frame is ready to be written out, do so */
179         if (sc->have_frame) {
180                 ast_write(bridge_channel->chan, &sc->frame);
181                 sc->have_frame = 0;
182         }
183
184         /* Alllll done */
185         ast_mutex_unlock(&sc->lock);
186
187         return AST_BRIDGE_WRITE_SUCCESS;
188 }
189
190 /*! \brief Function called when the channel's thread is poked */
191 static int softmix_bridge_poke(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
192 {
193         struct softmix_channel *sc = bridge_channel->bridge_pvt;
194
195         ast_mutex_lock(&sc->lock);
196
197         if (sc->have_frame) {
198                 ast_write(bridge_channel->chan, &sc->frame);
199                 sc->have_frame = 0;
200         }
201
202         ast_mutex_unlock(&sc->lock);
203
204         return 0;
205 }
206
207 /*! \brief Function which acts as the mixing thread */
208 static int softmix_bridge_thread(struct ast_bridge *bridge)
209 {
210         struct ast_timer *timer = (struct ast_timer *) bridge->bridge_pvt;
211         int timingfd = ast_timer_fd(timer);
212
213         ast_timer_set_rate(timer, (1000 / SOFTMIX_INTERVAL));
214
215         while (!bridge->stop && !bridge->refresh && bridge->array_num) {
216                 struct ast_bridge_channel *bridge_channel = NULL;
217                 short buf[SOFTMIX_DATALEN] = {0, };
218                 int timeout = -1;
219
220                 /* Go through pulling audio from each factory that has it available */
221                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
222                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
223
224                         ast_mutex_lock(&sc->lock);
225
226                         /* Try to get audio from the factory if available */
227                         if (ast_slinfactory_available(&sc->factory) >= SOFTMIX_SAMPLES && ast_slinfactory_read(&sc->factory, sc->our_buf, SOFTMIX_SAMPLES)) {
228                                 short *data1, *data2;
229                                 int i;
230
231                                 /* Put into the local final buffer */
232                                 for (i = 0, data1 = buf, data2 = sc->our_buf; i < SOFTMIX_DATALEN; i++, data1++, data2++)
233                                         ast_slinear_saturated_add(data1, data2);
234                                 /* Yay we have our own audio */
235                                 sc->have_audio = 1;
236                         } else {
237                                 /* Awww we don't have audio ;( */
238                                 sc->have_audio = 0;
239                         }
240                         ast_mutex_unlock(&sc->lock);
241                 }
242
243                 /* Next step go through removing the channel's own audio and creating a good frame... */
244                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
245                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
246                         int i = 0;
247
248                         /* Copy from local final buffer to our final buffer */
249                         memcpy(sc->final_buf, buf, sizeof(sc->final_buf));
250
251                         /* If we provided audio then take it out */
252                         if (sc->have_audio) {
253                                 for (i = 0; i < SOFTMIX_DATALEN; i++) {
254                                         ast_slinear_saturated_subtract(&sc->final_buf[i], &sc->our_buf[i]);
255                                 }
256                         }
257
258                         /* The frame is now ready for use... */
259                         sc->have_frame = 1;
260
261                         /* Poke bridged channel thread just in case */
262                         pthread_kill(bridge_channel->thread, SIGURG);
263                 }
264
265                 ao2_unlock(bridge);
266
267                 /* Wait for the timing source to tell us to wake up and get things done */
268                 ast_waitfor_n_fd(&timingfd, 1, &timeout, NULL);
269
270                 ast_timer_ack(timer, 1);
271
272                 ao2_lock(bridge);
273         }
274
275         return 0;
276 }
277
278 static struct ast_bridge_technology softmix_bridge = {
279         .name = "softmix",
280         .capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX | AST_BRIDGE_CAPABILITY_THREAD | AST_BRIDGE_CAPABILITY_MULTITHREADED,
281         .preference = AST_BRIDGE_PREFERENCE_LOW,
282 #ifdef SOFTMIX_16_SUPPORT
283         .formats = AST_FORMAT_SLINEAR16,
284 #else
285         .formats = AST_FORMAT_SLINEAR,
286 #endif
287         .create = softmix_bridge_create,
288         .destroy = softmix_bridge_destroy,
289         .join = softmix_bridge_join,
290         .leave = softmix_bridge_leave,
291         .write = softmix_bridge_write,
292         .thread = softmix_bridge_thread,
293         .poke = softmix_bridge_poke,
294 };
295
296 static int unload_module(void)
297 {
298         return ast_bridge_technology_unregister(&softmix_bridge);
299 }
300
301 static int load_module(void)
302 {
303         return ast_bridge_technology_register(&softmix_bridge);
304 }
305
306 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multi-party software based channel mixing");