Fix ConfBridge crash if no timing module loaded.
[asterisk/asterisk.git] / bridges / bridge_softmix.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2011, Digium, Inc.
5  *
6  * Joshua Colp <jcolp@digium.com>
7  * David Vossel <dvossel@digium.com>
8  *
9  * See http://www.asterisk.org for more information about
10  * the Asterisk project. Please do not directly contact
11  * any of the maintainers of this project for assistance;
12  * the project provides a web site, mailing lists and IRC
13  * channels for your use.
14  *
15  * This program is free software, distributed under the terms of
16  * the GNU General Public License Version 2. See the LICENSE file
17  * at the top of the source tree.
18  */
19
20 /*! \file
21  *
22  * \brief Multi-party software based channel mixing
23  *
24  * \author Joshua Colp <jcolp@digium.com>
25  * \author David Vossel <dvossel@digium.com>
26  *
27  * \ingroup bridges
28  */
29
30 /*** MODULEINFO
31         <support_level>core</support_level>
32  ***/
33
34 #include "asterisk.h"
35
36 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
37
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <sys/time.h>
42 #include <signal.h>
43 #include <errno.h>
44 #include <unistd.h>
45
46 #include "asterisk/module.h"
47 #include "asterisk/channel.h"
48 #include "asterisk/bridging.h"
49 #include "asterisk/bridging_technology.h"
50 #include "asterisk/frame.h"
51 #include "asterisk/options.h"
52 #include "asterisk/logger.h"
53 #include "asterisk/slinfactory.h"
54 #include "asterisk/astobj2.h"
55 #include "asterisk/timing.h"
56 #include "asterisk/translate.h"
57
58 #define MAX_DATALEN 8096
59
60 /*! \brief Interval at which mixing will take place. Valid options are 10, 20, and 40. */
61 #define DEFAULT_SOFTMIX_INTERVAL 20
62
63 /*! \brief Size of the buffer used for sample manipulation */
64 #define SOFTMIX_DATALEN(rate, interval) ((rate/50) * (interval / 10))
65
66 /*! \brief Number of samples we are dealing with */
67 #define SOFTMIX_SAMPLES(rate, interval) (SOFTMIX_DATALEN(rate, interval) / 2)
68
69 /*! \brief Number of mixing iterations to perform between gathering statistics. */
70 #define SOFTMIX_STAT_INTERVAL 100
71
72 /* This is the threshold in ms at which a channel's own audio will stop getting
73  * mixed out its own write audio stream because it is not talking. */
74 #define DEFAULT_SOFTMIX_SILENCE_THRESHOLD 2500
75 #define DEFAULT_SOFTMIX_TALKING_THRESHOLD 160
76
77 #define DEFAULT_ENERGY_HISTORY_LEN 150
78
79 struct video_follow_talker_data {
80         /*! audio energy history */
81         int energy_history[DEFAULT_ENERGY_HISTORY_LEN];
82         /*! The current slot being used in the history buffer, this
83          *  increments and wraps around */
84         int energy_history_cur_slot;
85         /*! The current energy sum used for averages. */
86         int energy_accum;
87         /*! The current energy average */
88         int energy_average;
89 };
90
91 /*! \brief Structure which contains per-channel mixing information */
92 struct softmix_channel {
93         /*! Lock to protect this structure */
94         ast_mutex_t lock;
95         /*! Factory which contains audio read in from the channel */
96         struct ast_slinfactory factory;
97         /*! Frame that contains mixed audio to be written out to the channel */
98         struct ast_frame write_frame;
99         /*! Frame that contains mixed audio read from the channel */
100         struct ast_frame read_frame;
101         /*! DSP for detecting silence */
102         struct ast_dsp *dsp;
103         /*! Bit used to indicate if a channel is talking or not. This affects how
104          * the channel's audio is mixed back to it. */
105         int talking:1;
106         /*! Bit used to indicate that the channel provided audio for this mixing interval */
107         int have_audio:1;
108         /*! Bit used to indicate that a frame is available to be written out to the channel */
109         int have_frame:1;
110         /*! Buffer containing final mixed audio from all sources */
111         short final_buf[MAX_DATALEN];
112         /*! Buffer containing only the audio from the channel */
113         short our_buf[MAX_DATALEN];
114         /*! Data pertaining to talker mode for video conferencing */
115         struct video_follow_talker_data video_talker;
116 };
117
118 struct softmix_bridge_data {
119         struct ast_timer *timer;
120         unsigned int internal_rate;
121         unsigned int internal_mixing_interval;
122 };
123
124 struct softmix_stats {
125                 /*! Each index represents a sample rate used above the internal rate. */
126                 unsigned int sample_rates[16];
127                 /*! Each index represents the number of channels using the same index in the sample_rates array.  */
128                 unsigned int num_channels[16];
129                 /*! the number of channels above the internal sample rate */
130                 unsigned int num_above_internal_rate;
131                 /*! the number of channels at the internal sample rate */
132                 unsigned int num_at_internal_rate;
133                 /*! the absolute highest sample rate supported by any channel in the bridge */
134                 unsigned int highest_supported_rate;
135                 /*! Is the sample rate locked by the bridge, if so what is that rate.*/
136                 unsigned int locked_rate;
137 };
138
139 struct softmix_mixing_array {
140         int max_num_entries;
141         int used_entries;
142         int16_t **buffers;
143 };
144
145 struct softmix_translate_helper_entry {
146         int num_times_requested; /*!< Once this entry is no longer requested, free the trans_pvt
147                                       and re-init if it was usable. */
148         struct ast_format dst_format; /*!< The destination format for this helper */
149         struct ast_trans_pvt *trans_pvt; /*!< the translator for this slot. */
150         struct ast_frame *out_frame; /*!< The output frame from the last translation */
151         AST_LIST_ENTRY(softmix_translate_helper_entry) entry;
152 };
153
154 struct softmix_translate_helper {
155         struct ast_format slin_src; /*!< the source format expected for all the translators */
156         AST_LIST_HEAD_NOLOCK(, softmix_translate_helper_entry) entries;
157 };
158
159 static struct softmix_translate_helper_entry *softmix_translate_helper_entry_alloc(struct ast_format *dst)
160 {
161         struct softmix_translate_helper_entry *entry;
162         if (!(entry = ast_calloc(1, sizeof(*entry)))) {
163                 return NULL;
164         }
165         ast_format_copy(&entry->dst_format, dst);
166         return entry;
167 }
168
169 static void *softmix_translate_helper_free_entry(struct softmix_translate_helper_entry *entry)
170 {
171         if (entry->trans_pvt) {
172                 ast_translator_free_path(entry->trans_pvt);
173         }
174         if (entry->out_frame) {
175                 ast_frfree(entry->out_frame);
176         }
177         ast_free(entry);
178         return NULL;
179 }
180
181 static void softmix_translate_helper_init(struct softmix_translate_helper *trans_helper, unsigned int sample_rate)
182 {
183         memset(trans_helper, 0, sizeof(*trans_helper));
184         ast_format_set(&trans_helper->slin_src, ast_format_slin_by_rate(sample_rate), 0);
185 }
186
187 static void softmix_translate_helper_destroy(struct softmix_translate_helper *trans_helper)
188 {
189         struct softmix_translate_helper_entry *entry;
190
191         while ((entry = AST_LIST_REMOVE_HEAD(&trans_helper->entries, entry))) {
192                 softmix_translate_helper_free_entry(entry);
193         }
194 }
195
196 static void softmix_translate_helper_change_rate(struct softmix_translate_helper *trans_helper, unsigned int sample_rate)
197 {
198         struct softmix_translate_helper_entry *entry;
199
200         ast_format_set(&trans_helper->slin_src, ast_format_slin_by_rate(sample_rate), 0);
201         AST_LIST_TRAVERSE_SAFE_BEGIN(&trans_helper->entries, entry, entry) {
202                 if (entry->trans_pvt) {
203                         ast_translator_free_path(entry->trans_pvt);
204                         if (!(entry->trans_pvt = ast_translator_build_path(&entry->dst_format, &trans_helper->slin_src))) {
205                                 AST_LIST_REMOVE_CURRENT(entry);
206                                 entry = softmix_translate_helper_free_entry(entry);
207                         }
208                 }
209         }
210         AST_LIST_TRAVERSE_SAFE_END;
211 }
212
213 /*!
214  * \internal
215  * \brief Get the next available audio on the softmix channel's read stream
216  * and determine if it should be mixed out or not on the write stream. 
217  *
218  * \retval pointer to buffer containing the exact number of samples requested on success.
219  * \retval NULL if no samples are present
220  */
221 static int16_t *softmix_process_read_audio(struct softmix_channel *sc, unsigned int num_samples)
222 {
223         if ((ast_slinfactory_available(&sc->factory) >= num_samples) &&
224                 ast_slinfactory_read(&sc->factory, sc->our_buf, num_samples)) {
225                 sc->have_audio = 1;
226                 return sc->our_buf;
227         }
228         sc->have_audio = 0;
229         return NULL;
230 }
231
232 /*!
233  * \internal
234  * \brief Process a softmix channel's write audio
235  *
236  * \details This function will remove the channel's talking from its own audio if present and
237  * possibly even do the channel's write translation for it depending on how many other
238  * channels use the same write format.
239  */
240 static void softmix_process_write_audio(struct softmix_translate_helper *trans_helper,
241         struct ast_format *raw_write_fmt,
242         struct softmix_channel *sc)
243 {
244         struct softmix_translate_helper_entry *entry = NULL;
245         int i;
246
247         /* If we provided audio that was not determined to be silence,
248          * then take it out while in slinear format. */
249         if (sc->have_audio && sc->talking) {
250                 for (i = 0; i < sc->write_frame.samples; i++) {
251                         ast_slinear_saturated_subtract(&sc->final_buf[i], &sc->our_buf[i]);
252                 }
253                 /* do not do any special write translate optimization if we had to make
254                  * a special mix for them to remove their own audio. */
255                 return;
256         }
257
258         AST_LIST_TRAVERSE(&trans_helper->entries, entry, entry) {
259                 if (ast_format_cmp(&entry->dst_format, raw_write_fmt) == AST_FORMAT_CMP_EQUAL) {
260                         entry->num_times_requested++;
261                 } else {
262                         continue;
263                 }
264                 if (!entry->trans_pvt && (entry->num_times_requested > 1)) {
265                         entry->trans_pvt = ast_translator_build_path(&entry->dst_format, &trans_helper->slin_src);
266                 }
267                 if (entry->trans_pvt && !entry->out_frame) {
268                         entry->out_frame = ast_translate(entry->trans_pvt, &sc->write_frame, 0);
269                 }
270                 if (entry->out_frame && (entry->out_frame->datalen < MAX_DATALEN)) {
271                         ast_format_copy(&sc->write_frame.subclass.format, &entry->out_frame->subclass.format);
272                         memcpy(sc->final_buf, entry->out_frame->data.ptr, entry->out_frame->datalen);
273                         sc->write_frame.datalen = entry->out_frame->datalen;
274                         sc->write_frame.samples = entry->out_frame->samples;
275                 }
276                 break;
277         }
278
279         /* add new entry into list if this format destination was not matched. */
280         if (!entry && (entry = softmix_translate_helper_entry_alloc(raw_write_fmt))) {
281                 AST_LIST_INSERT_HEAD(&trans_helper->entries, entry, entry);
282         }
283 }
284
285 static void softmix_translate_helper_cleanup(struct softmix_translate_helper *trans_helper)
286 {
287         struct softmix_translate_helper_entry *entry = NULL;
288         AST_LIST_TRAVERSE(&trans_helper->entries, entry, entry) {
289                 if (entry->out_frame) {
290                         ast_frfree(entry->out_frame);
291                         entry->out_frame = NULL;
292                 }
293                 entry->num_times_requested = 0;
294         }
295 }
296
297 static void softmix_bridge_data_destroy(void *obj)
298 {
299         struct softmix_bridge_data *softmix_data = obj;
300
301         if (softmix_data->timer) {
302                 ast_timer_close(softmix_data->timer);
303         }
304 }
305
306 /*! \brief Function called when a bridge is created */
307 static int softmix_bridge_create(struct ast_bridge *bridge)
308 {
309         struct softmix_bridge_data *softmix_data;
310
311         if (!(softmix_data = ao2_alloc(sizeof(*softmix_data), softmix_bridge_data_destroy))) {
312                 return -1;
313         }
314         if (!(softmix_data->timer = ast_timer_open())) {
315                 ao2_ref(softmix_data, -1);
316                 return -1;
317         }
318
319         /* start at 8khz, let it grow from there */
320         softmix_data->internal_rate = 8000;
321         softmix_data->internal_mixing_interval = DEFAULT_SOFTMIX_INTERVAL;
322
323         bridge->bridge_pvt = softmix_data;
324         return 0;
325 }
326
327 /*! \brief Function called when a bridge is destroyed */
328 static int softmix_bridge_destroy(struct ast_bridge *bridge)
329 {
330         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
331         if (!bridge->bridge_pvt) {
332                 return -1;
333         }
334         ao2_ref(softmix_data, -1);
335         bridge->bridge_pvt = NULL;
336         return 0;
337 }
338
339 static void set_softmix_bridge_data(int rate, int interval, struct ast_bridge_channel *bridge_channel, int reset)
340 {
341         struct softmix_channel *sc = bridge_channel->bridge_pvt;
342         unsigned int channel_read_rate = ast_format_rate(ast_channel_rawreadformat(bridge_channel->chan));
343
344         ast_mutex_lock(&sc->lock);
345         if (reset) {
346                 ast_slinfactory_destroy(&sc->factory);
347                 ast_dsp_free(sc->dsp);
348         }
349         /* Setup read/write frame parameters */
350         sc->write_frame.frametype = AST_FRAME_VOICE;
351         ast_format_set(&sc->write_frame.subclass.format, ast_format_slin_by_rate(rate), 0);
352         sc->write_frame.data.ptr = sc->final_buf;
353         sc->write_frame.datalen = SOFTMIX_DATALEN(rate, interval);
354         sc->write_frame.samples = SOFTMIX_SAMPLES(rate, interval);
355
356         sc->read_frame.frametype = AST_FRAME_VOICE;
357         ast_format_set(&sc->read_frame.subclass.format, ast_format_slin_by_rate(channel_read_rate), 0);
358         sc->read_frame.data.ptr = sc->our_buf;
359         sc->read_frame.datalen = SOFTMIX_DATALEN(channel_read_rate, interval);
360         sc->read_frame.samples = SOFTMIX_SAMPLES(channel_read_rate, interval);
361
362         /* Setup smoother */
363         ast_slinfactory_init_with_format(&sc->factory, &sc->write_frame.subclass.format);
364
365         /* set new read and write formats on channel. */
366         ast_set_read_format(bridge_channel->chan, &sc->read_frame.subclass.format);
367         ast_set_write_format(bridge_channel->chan, &sc->write_frame.subclass.format);
368
369         /* set up new DSP.  This is on the read side only right before the read frame enters the smoother.  */
370         sc->dsp = ast_dsp_new_with_rate(channel_read_rate);
371         /* we want to aggressively detect silence to avoid feedback */
372         if (bridge_channel->tech_args.talking_threshold) {
373                 ast_dsp_set_threshold(sc->dsp, bridge_channel->tech_args.talking_threshold);
374         } else {
375                 ast_dsp_set_threshold(sc->dsp, DEFAULT_SOFTMIX_TALKING_THRESHOLD);
376         }
377
378         ast_mutex_unlock(&sc->lock);
379 }
380
381 /*! \brief Function called when a channel is joined into the bridge */
382 static int softmix_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
383 {
384         struct softmix_channel *sc = NULL;
385         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
386
387         /* Create a new softmix_channel structure and allocate various things on it */
388         if (!(sc = ast_calloc(1, sizeof(*sc)))) {
389                 return -1;
390         }
391
392         /* Can't forget the lock */
393         ast_mutex_init(&sc->lock);
394
395         /* Can't forget to record our pvt structure within the bridged channel structure */
396         bridge_channel->bridge_pvt = sc;
397
398         set_softmix_bridge_data(softmix_data->internal_rate,
399                 softmix_data->internal_mixing_interval ? softmix_data->internal_mixing_interval : DEFAULT_SOFTMIX_INTERVAL,
400                 bridge_channel, 0);
401
402         return 0;
403 }
404
405 /*! \brief Function called when a channel leaves the bridge */
406 static int softmix_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
407 {
408         struct softmix_channel *sc = bridge_channel->bridge_pvt;
409
410         if (!(bridge_channel->bridge_pvt)) {
411                 return 0;
412         }
413         bridge_channel->bridge_pvt = NULL;
414
415         /* Drop mutex lock */
416         ast_mutex_destroy(&sc->lock);
417
418         /* Drop the factory */
419         ast_slinfactory_destroy(&sc->factory);
420
421         /* Drop the DSP */
422         ast_dsp_free(sc->dsp);
423
424         /* Eep! drop ourselves */
425         ast_free(sc);
426
427         return 0;
428 }
429
430 /*!
431  * \internal
432  * \brief If the bridging core passes DTMF to us, then they want it to be distributed out to all memebers. Do that here.
433  */
434 static void softmix_pass_dtmf(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
435 {
436         struct ast_bridge_channel *tmp;
437         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
438                 if (tmp == bridge_channel) {
439                         continue;
440                 }
441                 ast_write(tmp->chan, frame);
442         }
443 }
444
445 static void softmix_pass_video_top_priority(struct ast_bridge *bridge, struct ast_frame *frame)
446 {
447         struct ast_bridge_channel *tmp;
448         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
449                 if (tmp->suspended) {
450                         continue;
451                 }
452                 if (ast_bridge_is_video_src(bridge, tmp->chan) == 1) {
453                         ast_write(tmp->chan, frame);
454                         break;
455                 }
456         }
457 }
458
459 static void softmix_pass_video_all(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame, int echo)
460 {
461         struct ast_bridge_channel *tmp;
462         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
463                 if (tmp->suspended) {
464                         continue;
465                 }
466                 if ((tmp->chan == bridge_channel->chan) && !echo) {
467                         continue;
468                 }
469                 ast_write(tmp->chan, frame);
470         }
471 }
472
473 /*! \brief Function called when a channel writes a frame into the bridge */
474 static enum ast_bridge_write_result softmix_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
475 {
476         struct softmix_channel *sc = bridge_channel->bridge_pvt;
477         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
478         int totalsilence = 0;
479         int cur_energy = 0;
480         int silence_threshold = bridge_channel->tech_args.silence_threshold ?
481                 bridge_channel->tech_args.silence_threshold :
482                 DEFAULT_SOFTMIX_SILENCE_THRESHOLD;
483         char update_talking = -1;  /* if this is set to 0 or 1, tell the bridge that the channel has started or stopped talking. */
484         int res = AST_BRIDGE_WRITE_SUCCESS;
485
486         /* Only accept audio frames, all others are unsupported */
487         if (frame->frametype == AST_FRAME_DTMF_END || frame->frametype == AST_FRAME_DTMF_BEGIN) {
488                 softmix_pass_dtmf(bridge, bridge_channel, frame);
489                 goto bridge_write_cleanup;
490         } else if (frame->frametype != AST_FRAME_VOICE && frame->frametype != AST_FRAME_VIDEO) {
491                 res = AST_BRIDGE_WRITE_UNSUPPORTED;
492                 goto bridge_write_cleanup;
493         } else if (frame->datalen == 0) {
494                 goto bridge_write_cleanup;
495         }
496
497         /* Determine if this video frame should be distributed or not */
498         if (frame->frametype == AST_FRAME_VIDEO) {
499                 int num_src = ast_bridge_number_video_src(bridge);
500                 int video_src_priority = ast_bridge_is_video_src(bridge, bridge_channel->chan);
501
502                 switch (bridge->video_mode.mode) {
503                 case AST_BRIDGE_VIDEO_MODE_NONE:
504                         break;
505                 case AST_BRIDGE_VIDEO_MODE_SINGLE_SRC:
506                         if (video_src_priority == 1) {
507                                 softmix_pass_video_all(bridge, bridge_channel, frame, 1);
508                         }
509                         break;
510                 case AST_BRIDGE_VIDEO_MODE_TALKER_SRC:
511                         ast_mutex_lock(&sc->lock);
512                         ast_bridge_update_talker_src_video_mode(bridge, bridge_channel->chan, sc->video_talker.energy_average, ast_format_get_video_mark(&frame->subclass.format));
513                         ast_mutex_unlock(&sc->lock);
514                         if (video_src_priority == 1) {
515                                 int echo = num_src > 1 ? 0 : 1;
516                                 softmix_pass_video_all(bridge, bridge_channel, frame, echo);
517                         } else if (video_src_priority == 2) {
518                                 softmix_pass_video_top_priority(bridge, frame);
519                         }
520                         break;
521                 }
522                 goto bridge_write_cleanup;
523         }
524
525         /* If we made it here, we are going to write the frame into the conference */
526         ast_mutex_lock(&sc->lock);
527         ast_dsp_silence_with_energy(sc->dsp, frame, &totalsilence, &cur_energy);
528
529         if (bridge->video_mode.mode == AST_BRIDGE_VIDEO_MODE_TALKER_SRC) {
530                 int cur_slot = sc->video_talker.energy_history_cur_slot;
531                 sc->video_talker.energy_accum -= sc->video_talker.energy_history[cur_slot];
532                 sc->video_talker.energy_accum += cur_energy;
533                 sc->video_talker.energy_history[cur_slot] = cur_energy;
534                 sc->video_talker.energy_average = sc->video_talker.energy_accum / DEFAULT_ENERGY_HISTORY_LEN;
535                 sc->video_talker.energy_history_cur_slot++;
536                 if (sc->video_talker.energy_history_cur_slot == DEFAULT_ENERGY_HISTORY_LEN) {
537                         sc->video_talker.energy_history_cur_slot = 0; /* wrap around */
538                 }
539         }
540
541         if (totalsilence < silence_threshold) {
542                 if (!sc->talking) {
543                         update_talking = 1;
544                 }
545                 sc->talking = 1; /* tell the write process we have audio to be mixed out */
546         } else {
547                 if (sc->talking) {
548                         update_talking = 0;
549                 }
550                 sc->talking = 0;
551         }
552
553         /* Before adding audio in, make sure we haven't fallen behind. If audio has fallen
554          * behind 4 times the amount of samples mixed on every iteration of the mixer, Re-sync
555          * the audio by flushing the buffer before adding new audio in. */
556         if (ast_slinfactory_available(&sc->factory) > (4 * SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval))) {
557                 ast_slinfactory_flush(&sc->factory);
558         }
559
560         /* If a frame was provided add it to the smoother, unless drop silence is enabled and this frame
561          * is not determined to be talking. */
562         if (!(bridge_channel->tech_args.drop_silence && !sc->talking) &&
563                 (frame->frametype == AST_FRAME_VOICE && ast_format_is_slinear(&frame->subclass.format))) {
564                 ast_slinfactory_feed(&sc->factory, frame);
565         }
566
567         /* If a frame is ready to be written out, do so */
568         if (sc->have_frame) {
569                 ast_write(bridge_channel->chan, &sc->write_frame);
570                 sc->have_frame = 0;
571         }
572
573         /* Alllll done */
574         ast_mutex_unlock(&sc->lock);
575
576         if (update_talking != -1) {
577                 ast_bridge_notify_talking(bridge, bridge_channel, update_talking);
578         }
579
580         return res;
581
582 bridge_write_cleanup:
583         /* Even though the frame is not being written into the conference because it is not audio,
584          * we should use this opportunity to check to see if a frame is ready to be written out from
585          * the conference to the channel. */
586         ast_mutex_lock(&sc->lock);
587         if (sc->have_frame) {
588                 ast_write(bridge_channel->chan, &sc->write_frame);
589                 sc->have_frame = 0;
590         }
591         ast_mutex_unlock(&sc->lock);
592
593         return res;
594 }
595
596 /*! \brief Function called when the channel's thread is poked */
597 static int softmix_bridge_poke(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
598 {
599         struct softmix_channel *sc = bridge_channel->bridge_pvt;
600
601         ast_mutex_lock(&sc->lock);
602
603         if (sc->have_frame) {
604                 ast_write(bridge_channel->chan, &sc->write_frame);
605                 sc->have_frame = 0;
606         }
607
608         ast_mutex_unlock(&sc->lock);
609
610         return 0;
611 }
612
613 static void gather_softmix_stats(struct softmix_stats *stats,
614         const struct softmix_bridge_data *softmix_data,
615         struct ast_bridge_channel *bridge_channel)
616 {
617         int channel_native_rate;
618         int i;
619         /* Gather stats about channel sample rates. */
620         channel_native_rate = MAX(ast_format_rate(ast_channel_rawwriteformat(bridge_channel->chan)),
621                 ast_format_rate(ast_channel_rawreadformat(bridge_channel->chan)));
622
623         if (channel_native_rate > stats->highest_supported_rate) {
624                 stats->highest_supported_rate = channel_native_rate;
625         }
626         if (channel_native_rate > softmix_data->internal_rate) {
627                 for (i = 0; i < ARRAY_LEN(stats->sample_rates); i++) {
628                         if (stats->sample_rates[i] == channel_native_rate) {
629                                 stats->num_channels[i]++;
630                                 break;
631                         } else if (!stats->sample_rates[i]) {
632                                 stats->sample_rates[i] = channel_native_rate;
633                                 stats->num_channels[i]++;
634                                 break;
635                         }
636                 }
637                 stats->num_above_internal_rate++;
638         } else if (channel_native_rate == softmix_data->internal_rate) {
639                 stats->num_at_internal_rate++;
640         }
641 }
642 /*!
643  * \internal
644  * \brief Analyse mixing statistics and change bridges internal rate
645  * if necessary.
646  *
647  * \retval 0, no changes to internal rate 
648  * \ratval 1, internal rate was changed, update all the channels on the next mixing iteration.
649  */
650 static unsigned int analyse_softmix_stats(struct softmix_stats *stats, struct softmix_bridge_data *softmix_data)
651 {
652         int i;
653         /* Re-adjust the internal bridge sample rate if
654          * 1. The bridge's internal sample rate is locked in at a sample
655          *    rate other than the current sample rate being used.
656          * 2. two or more channels support a higher sample rate
657          * 3. no channels support the current sample rate or a higher rate
658          */
659         if (stats->locked_rate) {
660                 /* if the rate is locked by the bridge, only update it if it differs
661                  * from the current rate we are using. */
662                 if (softmix_data->internal_rate != stats->locked_rate) {
663                         softmix_data->internal_rate = stats->locked_rate;
664                         ast_debug(1, " Bridge is locked in at sample rate %d\n", softmix_data->internal_rate);
665                         return 1;
666                 }
667         } else if (stats->num_above_internal_rate >= 2) {
668                 /* the highest rate is just used as a starting point */
669                 unsigned int best_rate = stats->highest_supported_rate;
670                 int best_index = -1;
671
672                 for (i = 0; i < ARRAY_LEN(stats->num_channels); i++) {
673                         if (stats->num_channels[i]) {
674                                 break;
675                         }
676                         /* best_rate starts out being the first sample rate
677                          * greater than the internal sample rate that 2 or
678                          * more channels support. */
679                         if (stats->num_channels[i] >= 2 && (best_index == -1)) {
680                                 best_rate = stats->sample_rates[i];
681                                 best_index = i;
682                         /* If it has been detected that multiple rates above
683                          * the internal rate are present, compare those rates
684                          * to each other and pick the highest one two or more
685                          * channels support. */
686                         } else if (((best_index != -1) &&
687                                 (stats->num_channels[i] >= 2) &&
688                                 (stats->sample_rates[best_index] < stats->sample_rates[i]))) {
689                                 best_rate = stats->sample_rates[i];
690                                 best_index = i;
691                         /* It is possible that multiple channels exist with native sample
692                          * rates above the internal sample rate, but none of those channels
693                          * have the same rate in common.  In this case, the lowest sample
694                          * rate among those channels is picked. Over time as additional
695                          * statistic runs are made the internal sample rate number will
696                          * adjust to the most optimal sample rate, but it may take multiple
697                          * iterations. */
698                         } else if (best_index == -1) {
699                                 best_rate = MIN(best_rate, stats->sample_rates[i]);
700                         }
701                 }
702
703                 ast_debug(1, " Bridge changed from %d To %d\n", softmix_data->internal_rate, best_rate);
704                 softmix_data->internal_rate = best_rate;
705                 return 1;
706         } else if (!stats->num_at_internal_rate && !stats->num_above_internal_rate) {
707                 /* In this case, the highest supported rate is actually lower than the internal rate */
708                 softmix_data->internal_rate = stats->highest_supported_rate;
709                 ast_debug(1, " Bridge changed from %d to %d\n", softmix_data->internal_rate, stats->highest_supported_rate);
710                 return 1;
711         }
712         return 0;
713 }
714
715 static int softmix_mixing_array_init(struct softmix_mixing_array *mixing_array, unsigned int starting_num_entries)
716 {
717         memset(mixing_array, 0, sizeof(*mixing_array));
718         mixing_array->max_num_entries = starting_num_entries;
719         if (!(mixing_array->buffers = ast_calloc(mixing_array->max_num_entries, sizeof(int16_t *)))) {
720                 ast_log(LOG_NOTICE, "Failed to allocate softmix mixing structure. \n");
721                 return -1;
722         }
723         return 0;
724 }
725
726 static void softmix_mixing_array_destroy(struct softmix_mixing_array *mixing_array)
727 {
728         ast_free(mixing_array->buffers);
729 }
730
731 static int softmix_mixing_array_grow(struct softmix_mixing_array *mixing_array, unsigned int num_entries)
732 {
733         int16_t **tmp;
734         /* give it some room to grow since memory is cheap but allocations can be expensive */
735         mixing_array->max_num_entries = num_entries;
736         if (!(tmp = ast_realloc(mixing_array->buffers, (mixing_array->max_num_entries * sizeof(int16_t *))))) {
737                 ast_log(LOG_NOTICE, "Failed to re-allocate softmix mixing structure. \n");
738                 return -1;
739         }
740         mixing_array->buffers = tmp;
741         return 0;
742 }
743
744 /*! \brief Function which acts as the mixing thread */
745 static int softmix_bridge_thread(struct ast_bridge *bridge)
746 {
747         struct softmix_stats stats = { { 0 }, };
748         struct softmix_mixing_array mixing_array;
749         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
750         struct ast_timer *timer;
751         struct softmix_translate_helper trans_helper;
752         int16_t buf[MAX_DATALEN] = { 0, };
753         unsigned int stat_iteration_counter = 0; /* counts down, gather stats at zero and reset. */
754         int timingfd;
755         int update_all_rates = 0; /* set this when the internal sample rate has changed */
756         int i, x;
757         int res = -1;
758
759         if (!(softmix_data = bridge->bridge_pvt)) {
760                 goto softmix_cleanup;
761         }
762
763         ao2_ref(softmix_data, 1);
764         timer = softmix_data->timer;
765         timingfd = ast_timer_fd(timer);
766         softmix_translate_helper_init(&trans_helper, softmix_data->internal_rate);
767         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
768
769         /* Give the mixing array room to grow, memory is cheap but allocations are expensive. */
770         if (softmix_mixing_array_init(&mixing_array, bridge->num + 10)) {
771                 ast_log(LOG_NOTICE, "Failed to allocate softmix mixing structure. \n");
772                 goto softmix_cleanup;
773         }
774
775         while (!bridge->stop && !bridge->refresh && bridge->array_num) {
776                 struct ast_bridge_channel *bridge_channel = NULL;
777                 int timeout = -1;
778                 enum ast_format_id cur_slin_id = ast_format_slin_by_rate(softmix_data->internal_rate);
779                 unsigned int softmix_samples = SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
780                 unsigned int softmix_datalen = SOFTMIX_DATALEN(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
781
782                 if (softmix_datalen > MAX_DATALEN) {
783                         /* This should NEVER happen, but if it does we need to know about it. Almost
784                          * all the memcpys used during this process depend on this assumption.  Rather
785                          * than checking this over and over again through out the code, this single
786                          * verification is done on each iteration. */
787                         ast_log(LOG_WARNING, "Conference mixing error, requested mixing length greater than mixing buffer.\n");
788                         goto softmix_cleanup;
789                 }
790
791                 /* Grow the mixing array buffer as participants are added. */
792                 if (mixing_array.max_num_entries < bridge->num && softmix_mixing_array_grow(&mixing_array, bridge->num + 5)) {
793                         goto softmix_cleanup;
794                 }
795
796                 /* init the number of buffers stored in the mixing array to 0.
797                  * As buffers are added for mixing, this number is incremented. */
798                 mixing_array.used_entries = 0;
799
800                 /* These variables help determine if a rate change is required */
801                 if (!stat_iteration_counter) {
802                         memset(&stats, 0, sizeof(stats));
803                         stats.locked_rate = bridge->internal_sample_rate;
804                 }
805
806                 /* If the sample rate has changed, update the translator helper */
807                 if (update_all_rates) {
808                         softmix_translate_helper_change_rate(&trans_helper, softmix_data->internal_rate);
809                 }
810
811                 /* Go through pulling audio from each factory that has it available */
812                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
813                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
814
815                         /* Update the sample rate to match the bridge's native sample rate if necessary. */
816                         if (update_all_rates) {
817                                 set_softmix_bridge_data(softmix_data->internal_rate, softmix_data->internal_mixing_interval, bridge_channel, 1);
818                         }
819
820                         /* If stat_iteration_counter is 0, then collect statistics during this mixing interation */
821                         if (!stat_iteration_counter) {
822                                 gather_softmix_stats(&stats, softmix_data, bridge_channel);
823                         }
824
825                         /* if the channel is suspended, don't check for audio, but still gather stats */
826                         if (bridge_channel->suspended) {
827                                 continue;
828                         }
829
830                         /* Try to get audio from the factory if available */
831                         ast_mutex_lock(&sc->lock);
832                         if ((mixing_array.buffers[mixing_array.used_entries] = softmix_process_read_audio(sc, softmix_samples))) {
833                                 mixing_array.used_entries++;
834                         }
835                         ast_mutex_unlock(&sc->lock);
836                 }
837
838                 /* mix it like crazy */
839                 memset(buf, 0, softmix_datalen);
840                 for (i = 0; i < mixing_array.used_entries; i++) {
841                         for (x = 0; x < softmix_samples; x++) {
842                                 ast_slinear_saturated_add(buf + x, mixing_array.buffers[i] + x);
843                         }
844                 }
845
846                 /* Next step go through removing the channel's own audio and creating a good frame... */
847                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
848                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
849
850                         if (bridge_channel->suspended) {
851                                 continue;
852                         }
853
854                         ast_mutex_lock(&sc->lock);
855
856                         /* Make SLINEAR write frame from local buffer */
857                         if (sc->write_frame.subclass.format.id != cur_slin_id) {
858                                 ast_format_set(&sc->write_frame.subclass.format, cur_slin_id, 0);
859                         }
860                         sc->write_frame.datalen = softmix_datalen;
861                         sc->write_frame.samples = softmix_samples;
862                         memcpy(sc->final_buf, buf, softmix_datalen);
863
864                         /* process the softmix channel's new write audio */
865                         softmix_process_write_audio(&trans_helper, ast_channel_rawwriteformat(bridge_channel->chan), sc);
866
867                         /* The frame is now ready for use... */
868                         sc->have_frame = 1;
869
870                         ast_mutex_unlock(&sc->lock);
871
872                         /* Poke bridged channel thread just in case */
873                         pthread_kill(bridge_channel->thread, SIGURG);
874                 }
875
876                 update_all_rates = 0;
877                 if (!stat_iteration_counter) {
878                         update_all_rates = analyse_softmix_stats(&stats, softmix_data);
879                         stat_iteration_counter = SOFTMIX_STAT_INTERVAL;
880                 }
881                 stat_iteration_counter--;
882
883                 ao2_unlock(bridge);
884                 /* cleanup any translation frame data from the previous mixing iteration. */
885                 softmix_translate_helper_cleanup(&trans_helper);
886                 /* Wait for the timing source to tell us to wake up and get things done */
887                 ast_waitfor_n_fd(&timingfd, 1, &timeout, NULL);
888                 ast_timer_ack(timer, 1);
889                 ao2_lock(bridge);
890
891                 /* make sure to detect mixing interval changes if they occur. */
892                 if (bridge->internal_mixing_interval && (bridge->internal_mixing_interval != softmix_data->internal_mixing_interval)) {
893                         softmix_data->internal_mixing_interval = bridge->internal_mixing_interval;
894                         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
895                         update_all_rates = 1; /* if the interval changes, the rates must be adjusted as well just to be notified new interval.*/
896                 }
897         }
898
899         res = 0;
900
901 softmix_cleanup:
902         softmix_translate_helper_destroy(&trans_helper);
903         softmix_mixing_array_destroy(&mixing_array);
904         if (softmix_data) {
905                 ao2_ref(softmix_data, -1);
906         }
907         return res;
908 }
909
910 static struct ast_bridge_technology softmix_bridge = {
911         .name = "softmix",
912         .capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX | AST_BRIDGE_CAPABILITY_THREAD | AST_BRIDGE_CAPABILITY_MULTITHREADED | AST_BRIDGE_CAPABILITY_OPTIMIZE | AST_BRIDGE_CAPABILITY_VIDEO,
913         .preference = AST_BRIDGE_PREFERENCE_LOW,
914         .create = softmix_bridge_create,
915         .destroy = softmix_bridge_destroy,
916         .join = softmix_bridge_join,
917         .leave = softmix_bridge_leave,
918         .write = softmix_bridge_write,
919         .thread = softmix_bridge_thread,
920         .poke = softmix_bridge_poke,
921 };
922
923 static int unload_module(void)
924 {
925         ast_format_cap_destroy(softmix_bridge.format_capabilities);
926         return ast_bridge_technology_unregister(&softmix_bridge);
927 }
928
929 static int load_module(void)
930 {
931         struct ast_format tmp;
932         if (!(softmix_bridge.format_capabilities = ast_format_cap_alloc())) {
933                 return AST_MODULE_LOAD_DECLINE;
934         }
935         ast_format_cap_add(softmix_bridge.format_capabilities, ast_format_set(&tmp, AST_FORMAT_SLINEAR, 0));
936         return ast_bridge_technology_register(&softmix_bridge);
937 }
938
939 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multi-party software based channel mixing");