Merged revisions 328247 via svnmerge from
[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         ast_timer_close(softmix_data->timer);
301 }
302
303 /*! \brief Function called when a bridge is created */
304 static int softmix_bridge_create(struct ast_bridge *bridge)
305 {
306         struct softmix_bridge_data *softmix_data;
307
308         if (!(softmix_data = ao2_alloc(sizeof(*softmix_data), softmix_bridge_data_destroy))) {
309                 return -1;
310         }
311         if (!(softmix_data->timer = ast_timer_open())) {
312                 ao2_ref(softmix_data, -1);
313                 return -1;
314         }
315
316         /* start at 8khz, let it grow from there */
317         softmix_data->internal_rate = 8000;
318         softmix_data->internal_mixing_interval = DEFAULT_SOFTMIX_INTERVAL;
319
320         bridge->bridge_pvt = softmix_data;
321         return 0;
322 }
323
324 /*! \brief Function called when a bridge is destroyed */
325 static int softmix_bridge_destroy(struct ast_bridge *bridge)
326 {
327         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
328         if (!bridge->bridge_pvt) {
329                 return -1;
330         }
331         ao2_ref(softmix_data, -1);
332         bridge->bridge_pvt = NULL;
333         return 0;
334 }
335
336 static void set_softmix_bridge_data(int rate, int interval, struct ast_bridge_channel *bridge_channel, int reset)
337 {
338         struct softmix_channel *sc = bridge_channel->bridge_pvt;
339         unsigned int channel_read_rate = ast_format_rate(&bridge_channel->chan->rawreadformat);
340
341         ast_mutex_lock(&sc->lock);
342         if (reset) {
343                 ast_slinfactory_destroy(&sc->factory);
344                 ast_dsp_free(sc->dsp);
345         }
346         /* Setup read/write frame parameters */
347         sc->write_frame.frametype = AST_FRAME_VOICE;
348         ast_format_set(&sc->write_frame.subclass.format, ast_format_slin_by_rate(rate), 0);
349         sc->write_frame.data.ptr = sc->final_buf;
350         sc->write_frame.datalen = SOFTMIX_DATALEN(rate, interval);
351         sc->write_frame.samples = SOFTMIX_SAMPLES(rate, interval);
352
353         sc->read_frame.frametype = AST_FRAME_VOICE;
354         ast_format_set(&sc->read_frame.subclass.format, ast_format_slin_by_rate(channel_read_rate), 0);
355         sc->read_frame.data.ptr = sc->our_buf;
356         sc->read_frame.datalen = SOFTMIX_DATALEN(channel_read_rate, interval);
357         sc->read_frame.samples = SOFTMIX_SAMPLES(channel_read_rate, interval);
358
359         /* Setup smoother */
360         ast_slinfactory_init_with_format(&sc->factory, &sc->write_frame.subclass.format);
361
362         /* set new read and write formats on channel. */
363         ast_set_read_format(bridge_channel->chan, &sc->read_frame.subclass.format);
364         ast_set_write_format(bridge_channel->chan, &sc->write_frame.subclass.format);
365
366         /* set up new DSP.  This is on the read side only right before the read frame enters the smoother.  */
367         sc->dsp = ast_dsp_new_with_rate(channel_read_rate);
368         /* we want to aggressively detect silence to avoid feedback */
369         if (bridge_channel->tech_args.talking_threshold) {
370                 ast_dsp_set_threshold(sc->dsp, bridge_channel->tech_args.talking_threshold);
371         } else {
372                 ast_dsp_set_threshold(sc->dsp, DEFAULT_SOFTMIX_TALKING_THRESHOLD);
373         }
374
375         ast_mutex_unlock(&sc->lock);
376 }
377
378 /*! \brief Function called when a channel is joined into the bridge */
379 static int softmix_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
380 {
381         struct softmix_channel *sc = NULL;
382         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
383
384         /* Create a new softmix_channel structure and allocate various things on it */
385         if (!(sc = ast_calloc(1, sizeof(*sc)))) {
386                 return -1;
387         }
388
389         /* Can't forget the lock */
390         ast_mutex_init(&sc->lock);
391
392         /* Can't forget to record our pvt structure within the bridged channel structure */
393         bridge_channel->bridge_pvt = sc;
394
395         set_softmix_bridge_data(softmix_data->internal_rate,
396                 softmix_data->internal_mixing_interval ? softmix_data->internal_mixing_interval : DEFAULT_SOFTMIX_INTERVAL,
397                 bridge_channel, 0);
398
399         return 0;
400 }
401
402 /*! \brief Function called when a channel leaves the bridge */
403 static int softmix_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
404 {
405         struct softmix_channel *sc = bridge_channel->bridge_pvt;
406
407         if (!(bridge_channel->bridge_pvt)) {
408                 return 0;
409         }
410         bridge_channel->bridge_pvt = NULL;
411
412         /* Drop mutex lock */
413         ast_mutex_destroy(&sc->lock);
414
415         /* Drop the factory */
416         ast_slinfactory_destroy(&sc->factory);
417
418         /* Drop the DSP */
419         ast_dsp_free(sc->dsp);
420
421         /* Eep! drop ourselves */
422         ast_free(sc);
423
424         return 0;
425 }
426
427 /*!
428  * \internal
429  * \brief If the bridging core passes DTMF to us, then they want it to be distributed out to all memebers. Do that here.
430  */
431 static void softmix_pass_dtmf(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
432 {
433         struct ast_bridge_channel *tmp;
434         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
435                 if (tmp == bridge_channel) {
436                         continue;
437                 }
438                 ast_write(tmp->chan, frame);
439         }
440 }
441
442 static void softmix_pass_video_top_priority(struct ast_bridge *bridge, struct ast_frame *frame)
443 {
444         struct ast_bridge_channel *tmp;
445         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
446                 if (tmp->suspended) {
447                         continue;
448                 }
449                 if (ast_bridge_is_video_src(bridge, tmp->chan) == 1) {
450                         ast_write(tmp->chan, frame);
451                         break;
452                 }
453         }
454 }
455
456 static void softmix_pass_video_all(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame, int echo)
457 {
458         struct ast_bridge_channel *tmp;
459         AST_LIST_TRAVERSE(&bridge->channels, tmp, entry) {
460                 if (tmp->suspended) {
461                         continue;
462                 }
463                 if ((tmp->chan == bridge_channel->chan) && !echo) {
464                         continue;
465                 }
466                 ast_write(tmp->chan, frame);
467         }
468 }
469
470 /*! \brief Function called when a channel writes a frame into the bridge */
471 static enum ast_bridge_write_result softmix_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
472 {
473         struct softmix_channel *sc = bridge_channel->bridge_pvt;
474         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
475         int totalsilence = 0;
476         int cur_energy = 0;
477         int silence_threshold = bridge_channel->tech_args.silence_threshold ?
478                 bridge_channel->tech_args.silence_threshold :
479                 DEFAULT_SOFTMIX_SILENCE_THRESHOLD;
480         char update_talking = -1;  /* if this is set to 0 or 1, tell the bridge that the channel has started or stopped talking. */
481         int res = AST_BRIDGE_WRITE_SUCCESS;
482
483         /* Only accept audio frames, all others are unsupported */
484         if (frame->frametype == AST_FRAME_DTMF_END || frame->frametype == AST_FRAME_DTMF_BEGIN) {
485                 softmix_pass_dtmf(bridge, bridge_channel, frame);
486                 goto bridge_write_cleanup;
487         } else if (frame->frametype != AST_FRAME_VOICE && frame->frametype != AST_FRAME_VIDEO) {
488                 res = AST_BRIDGE_WRITE_UNSUPPORTED;
489                 goto bridge_write_cleanup;
490         } else if (frame->datalen == 0) {
491                 goto bridge_write_cleanup;
492         }
493
494         /* Determine if this video frame should be distributed or not */
495         if (frame->frametype == AST_FRAME_VIDEO) {
496                 int num_src = ast_bridge_number_video_src(bridge);
497                 int video_src_priority = ast_bridge_is_video_src(bridge, bridge_channel->chan);
498
499                 switch (bridge->video_mode.mode) {
500                 case AST_BRIDGE_VIDEO_MODE_NONE:
501                         break;
502                 case AST_BRIDGE_VIDEO_MODE_SINGLE_SRC:
503                         if (video_src_priority == 1) {
504                                 softmix_pass_video_all(bridge, bridge_channel, frame, 1);
505                         }
506                         break;
507                 case AST_BRIDGE_VIDEO_MODE_TALKER_SRC:
508                         ast_mutex_lock(&sc->lock);
509                         ast_bridge_update_talker_src_video_mode(bridge, bridge_channel->chan, sc->video_talker.energy_average, ast_format_get_video_mark(&frame->subclass.format));
510                         ast_mutex_unlock(&sc->lock);
511                         if (video_src_priority == 1) {
512                                 int echo = num_src > 1 ? 0 : 1;
513                                 softmix_pass_video_all(bridge, bridge_channel, frame, echo);
514                         } else if (video_src_priority == 2) {
515                                 softmix_pass_video_top_priority(bridge, frame);
516                         }
517                         break;
518                 }
519                 goto bridge_write_cleanup;
520         }
521
522         /* If we made it here, we are going to write the frame into the conference */
523         ast_mutex_lock(&sc->lock);
524         ast_dsp_silence_with_energy(sc->dsp, frame, &totalsilence, &cur_energy);
525
526         if (bridge->video_mode.mode == AST_BRIDGE_VIDEO_MODE_TALKER_SRC) {
527                 int cur_slot = sc->video_talker.energy_history_cur_slot;
528                 sc->video_talker.energy_accum -= sc->video_talker.energy_history[cur_slot];
529                 sc->video_talker.energy_accum += cur_energy;
530                 sc->video_talker.energy_history[cur_slot] = cur_energy;
531                 sc->video_talker.energy_average = sc->video_talker.energy_accum / DEFAULT_ENERGY_HISTORY_LEN;
532                 sc->video_talker.energy_history_cur_slot++;
533                 if (sc->video_talker.energy_history_cur_slot == DEFAULT_ENERGY_HISTORY_LEN) {
534                         sc->video_talker.energy_history_cur_slot = 0; /* wrap around */
535                 }
536         }
537
538         if (totalsilence < silence_threshold) {
539                 if (!sc->talking) {
540                         update_talking = 1;
541                 }
542                 sc->talking = 1; /* tell the write process we have audio to be mixed out */
543         } else {
544                 if (sc->talking) {
545                         update_talking = 0;
546                 }
547                 sc->talking = 0;
548         }
549
550         /* Before adding audio in, make sure we haven't fallen behind. If audio has fallen
551          * behind 4 times the amount of samples mixed on every iteration of the mixer, Re-sync
552          * the audio by flushing the buffer before adding new audio in. */
553         if (ast_slinfactory_available(&sc->factory) > (4 * SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval))) {
554                 ast_slinfactory_flush(&sc->factory);
555         }
556
557         /* If a frame was provided add it to the smoother, unless drop silence is enabled and this frame
558          * is not determined to be talking. */
559         if (!(bridge_channel->tech_args.drop_silence && !sc->talking) &&
560                 (frame->frametype == AST_FRAME_VOICE && ast_format_is_slinear(&frame->subclass.format))) {
561                 ast_slinfactory_feed(&sc->factory, frame);
562         }
563
564         /* If a frame is ready to be written out, do so */
565         if (sc->have_frame) {
566                 ast_write(bridge_channel->chan, &sc->write_frame);
567                 sc->have_frame = 0;
568         }
569
570         /* Alllll done */
571         ast_mutex_unlock(&sc->lock);
572
573         if (update_talking != -1) {
574                 ast_bridge_notify_talking(bridge, bridge_channel, update_talking);
575         }
576
577         return res;
578
579 bridge_write_cleanup:
580         /* Even though the frame is not being written into the conference because it is not audio,
581          * we should use this opportunity to check to see if a frame is ready to be written out from
582          * the conference to the channel. */
583         ast_mutex_lock(&sc->lock);
584         if (sc->have_frame) {
585                 ast_write(bridge_channel->chan, &sc->write_frame);
586                 sc->have_frame = 0;
587         }
588         ast_mutex_unlock(&sc->lock);
589
590         return res;
591 }
592
593 /*! \brief Function called when the channel's thread is poked */
594 static int softmix_bridge_poke(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
595 {
596         struct softmix_channel *sc = bridge_channel->bridge_pvt;
597
598         ast_mutex_lock(&sc->lock);
599
600         if (sc->have_frame) {
601                 ast_write(bridge_channel->chan, &sc->write_frame);
602                 sc->have_frame = 0;
603         }
604
605         ast_mutex_unlock(&sc->lock);
606
607         return 0;
608 }
609
610 static void gather_softmix_stats(struct softmix_stats *stats,
611         const struct softmix_bridge_data *softmix_data,
612         struct ast_bridge_channel *bridge_channel)
613 {
614         int channel_native_rate;
615         int i;
616         /* Gather stats about channel sample rates. */
617         channel_native_rate = MAX(ast_format_rate(&bridge_channel->chan->rawwriteformat),
618                 ast_format_rate(&bridge_channel->chan->rawreadformat));
619
620         if (channel_native_rate > stats->highest_supported_rate) {
621                 stats->highest_supported_rate = channel_native_rate;
622         }
623         if (channel_native_rate > softmix_data->internal_rate) {
624                 for (i = 0; i < ARRAY_LEN(stats->sample_rates); i++) {
625                         if (stats->sample_rates[i] == channel_native_rate) {
626                                 stats->num_channels[i]++;
627                                 break;
628                         } else if (!stats->sample_rates[i]) {
629                                 stats->sample_rates[i] = channel_native_rate;
630                                 stats->num_channels[i]++;
631                                 break;
632                         }
633                 }
634                 stats->num_above_internal_rate++;
635         } else if (channel_native_rate == softmix_data->internal_rate) {
636                 stats->num_at_internal_rate++;
637         }
638 }
639 /*!
640  * \internal
641  * \brief Analyse mixing statistics and change bridges internal rate
642  * if necessary.
643  *
644  * \retval 0, no changes to internal rate 
645  * \ratval 1, internal rate was changed, update all the channels on the next mixing iteration.
646  */
647 static unsigned int analyse_softmix_stats(struct softmix_stats *stats, struct softmix_bridge_data *softmix_data)
648 {
649         int i;
650         /* Re-adjust the internal bridge sample rate if
651          * 1. The bridge's internal sample rate is locked in at a sample
652          *    rate other than the current sample rate being used.
653          * 2. two or more channels support a higher sample rate
654          * 3. no channels support the current sample rate or a higher rate
655          */
656         if (stats->locked_rate) {
657                 /* if the rate is locked by the bridge, only update it if it differs
658                  * from the current rate we are using. */
659                 if (softmix_data->internal_rate != stats->locked_rate) {
660                         softmix_data->internal_rate = stats->locked_rate;
661                         ast_debug(1, " Bridge is locked in at sample rate %d\n", softmix_data->internal_rate);
662                         return 1;
663                 }
664         } else if (stats->num_above_internal_rate >= 2) {
665                 /* the highest rate is just used as a starting point */
666                 unsigned int best_rate = stats->highest_supported_rate;
667                 int best_index = -1;
668
669                 for (i = 0; i < ARRAY_LEN(stats->num_channels); i++) {
670                         if (stats->num_channels[i]) {
671                                 break;
672                         }
673                         /* best_rate starts out being the first sample rate
674                          * greater than the internal sample rate that 2 or
675                          * more channels support. */
676                         if (stats->num_channels[i] >= 2 && (best_index == -1)) {
677                                 best_rate = stats->sample_rates[i];
678                                 best_index = i;
679                         /* If it has been detected that multiple rates above
680                          * the internal rate are present, compare those rates
681                          * to each other and pick the highest one two or more
682                          * channels support. */
683                         } else if (((best_index != -1) &&
684                                 (stats->num_channels[i] >= 2) &&
685                                 (stats->sample_rates[best_index] < stats->sample_rates[i]))) {
686                                 best_rate = stats->sample_rates[i];
687                                 best_index = i;
688                         /* It is possible that multiple channels exist with native sample
689                          * rates above the internal sample rate, but none of those channels
690                          * have the same rate in common.  In this case, the lowest sample
691                          * rate among those channels is picked. Over time as additional
692                          * statistic runs are made the internal sample rate number will
693                          * adjust to the most optimal sample rate, but it may take multiple
694                          * iterations. */
695                         } else if (best_index == -1) {
696                                 best_rate = MIN(best_rate, stats->sample_rates[i]);
697                         }
698                 }
699
700                 ast_debug(1, " Bridge changed from %d To %d\n", softmix_data->internal_rate, best_rate);
701                 softmix_data->internal_rate = best_rate;
702                 return 1;
703         } else if (!stats->num_at_internal_rate && !stats->num_above_internal_rate) {
704                 /* In this case, the highest supported rate is actually lower than the internal rate */
705                 softmix_data->internal_rate = stats->highest_supported_rate;
706                 ast_debug(1, " Bridge changed from %d to %d\n", softmix_data->internal_rate, stats->highest_supported_rate);
707                 return 1;
708         }
709         return 0;
710 }
711
712 static int softmix_mixing_array_init(struct softmix_mixing_array *mixing_array, unsigned int starting_num_entries)
713 {
714         memset(mixing_array, 0, sizeof(*mixing_array));
715         mixing_array->max_num_entries = starting_num_entries;
716         if (!(mixing_array->buffers = ast_calloc(mixing_array->max_num_entries, sizeof(int16_t *)))) {
717                 ast_log(LOG_NOTICE, "Failed to allocate softmix mixing structure. \n");
718                 return -1;
719         }
720         return 0;
721 }
722
723 static void softmix_mixing_array_destroy(struct softmix_mixing_array *mixing_array)
724 {
725         ast_free(mixing_array->buffers);
726 }
727
728 static int softmix_mixing_array_grow(struct softmix_mixing_array *mixing_array, unsigned int num_entries)
729 {
730         int16_t **tmp;
731         /* give it some room to grow since memory is cheap but allocations can be expensive */
732         mixing_array->max_num_entries = num_entries;
733         if (!(tmp = ast_realloc(mixing_array->buffers, (mixing_array->max_num_entries * sizeof(int16_t *))))) {
734                 ast_log(LOG_NOTICE, "Failed to re-allocate softmix mixing structure. \n");
735                 return -1;
736         }
737         mixing_array->buffers = tmp;
738         return 0;
739 }
740
741 /*! \brief Function which acts as the mixing thread */
742 static int softmix_bridge_thread(struct ast_bridge *bridge)
743 {
744         struct softmix_stats stats = { { 0 }, };
745         struct softmix_mixing_array mixing_array;
746         struct softmix_bridge_data *softmix_data = bridge->bridge_pvt;
747         struct ast_timer *timer;
748         struct softmix_translate_helper trans_helper;
749         int16_t buf[MAX_DATALEN] = { 0, };
750         unsigned int stat_iteration_counter = 0; /* counts down, gather stats at zero and reset. */
751         int timingfd;
752         int update_all_rates = 0; /* set this when the internal sample rate has changed */
753         int i, x;
754         int res = -1;
755
756         if (!(softmix_data = bridge->bridge_pvt)) {
757                 goto softmix_cleanup;
758         }
759
760         ao2_ref(softmix_data, 1);
761         timer = softmix_data->timer;
762         timingfd = ast_timer_fd(timer);
763         softmix_translate_helper_init(&trans_helper, softmix_data->internal_rate);
764         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
765
766         /* Give the mixing array room to grow, memory is cheap but allocations are expensive. */
767         if (softmix_mixing_array_init(&mixing_array, bridge->num + 10)) {
768                 ast_log(LOG_NOTICE, "Failed to allocate softmix mixing structure. \n");
769                 goto softmix_cleanup;
770         }
771
772         while (!bridge->stop && !bridge->refresh && bridge->array_num) {
773                 struct ast_bridge_channel *bridge_channel = NULL;
774                 int timeout = -1;
775                 enum ast_format_id cur_slin_id = ast_format_slin_by_rate(softmix_data->internal_rate);
776                 unsigned int softmix_samples = SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
777                 unsigned int softmix_datalen = SOFTMIX_DATALEN(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
778
779                 if (softmix_datalen > MAX_DATALEN) {
780                         /* This should NEVER happen, but if it does we need to know about it. Almost
781                          * all the memcpys used during this process depend on this assumption.  Rather
782                          * than checking this over and over again through out the code, this single
783                          * verification is done on each iteration. */
784                         ast_log(LOG_WARNING, "Conference mixing error, requested mixing length greater than mixing buffer.\n");
785                         goto softmix_cleanup;
786                 }
787
788                 /* Grow the mixing array buffer as participants are added. */
789                 if (mixing_array.max_num_entries < bridge->num && softmix_mixing_array_grow(&mixing_array, bridge->num + 5)) {
790                         goto softmix_cleanup;
791                 }
792
793                 /* init the number of buffers stored in the mixing array to 0.
794                  * As buffers are added for mixing, this number is incremented. */
795                 mixing_array.used_entries = 0;
796
797                 /* These variables help determine if a rate change is required */
798                 if (!stat_iteration_counter) {
799                         memset(&stats, 0, sizeof(stats));
800                         stats.locked_rate = bridge->internal_sample_rate;
801                 }
802
803                 /* If the sample rate has changed, update the translator helper */
804                 if (update_all_rates) {
805                         softmix_translate_helper_change_rate(&trans_helper, softmix_data->internal_rate);
806                 }
807
808                 /* Go through pulling audio from each factory that has it available */
809                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
810                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
811
812                         /* Update the sample rate to match the bridge's native sample rate if necessary. */
813                         if (update_all_rates) {
814                                 set_softmix_bridge_data(softmix_data->internal_rate, softmix_data->internal_mixing_interval, bridge_channel, 1);
815                         }
816
817                         /* If stat_iteration_counter is 0, then collect statistics during this mixing interation */
818                         if (!stat_iteration_counter) {
819                                 gather_softmix_stats(&stats, softmix_data, bridge_channel);
820                         }
821
822                         /* if the channel is suspended, don't check for audio, but still gather stats */
823                         if (bridge_channel->suspended) {
824                                 continue;
825                         }
826
827                         /* Try to get audio from the factory if available */
828                         ast_mutex_lock(&sc->lock);
829                         if ((mixing_array.buffers[mixing_array.used_entries] = softmix_process_read_audio(sc, softmix_samples))) {
830                                 mixing_array.used_entries++;
831                         }
832                         ast_mutex_unlock(&sc->lock);
833                 }
834
835                 /* mix it like crazy */
836                 memset(buf, 0, softmix_datalen);
837                 for (i = 0; i < mixing_array.used_entries; i++) {
838                         for (x = 0; x < softmix_samples; x++) {
839                                 ast_slinear_saturated_add(buf + x, mixing_array.buffers[i] + x);
840                         }
841                 }
842
843                 /* Next step go through removing the channel's own audio and creating a good frame... */
844                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
845                         struct softmix_channel *sc = bridge_channel->bridge_pvt;
846
847                         if (bridge_channel->suspended) {
848                                 continue;
849                         }
850
851                         ast_mutex_lock(&sc->lock);
852
853                         /* Make SLINEAR write frame from local buffer */
854                         if (sc->write_frame.subclass.format.id != cur_slin_id) {
855                                 ast_format_set(&sc->write_frame.subclass.format, cur_slin_id, 0);
856                         }
857                         sc->write_frame.datalen = softmix_datalen;
858                         sc->write_frame.samples = softmix_samples;
859                         memcpy(sc->final_buf, buf, softmix_datalen);
860
861                         /* process the softmix channel's new write audio */
862                         softmix_process_write_audio(&trans_helper, &bridge_channel->chan->rawwriteformat, sc);
863
864                         /* The frame is now ready for use... */
865                         sc->have_frame = 1;
866
867                         ast_mutex_unlock(&sc->lock);
868
869                         /* Poke bridged channel thread just in case */
870                         pthread_kill(bridge_channel->thread, SIGURG);
871                 }
872
873                 update_all_rates = 0;
874                 if (!stat_iteration_counter) {
875                         update_all_rates = analyse_softmix_stats(&stats, softmix_data);
876                         stat_iteration_counter = SOFTMIX_STAT_INTERVAL;
877                 }
878                 stat_iteration_counter--;
879
880                 ao2_unlock(bridge);
881                 /* cleanup any translation frame data from the previous mixing iteration. */
882                 softmix_translate_helper_cleanup(&trans_helper);
883                 /* Wait for the timing source to tell us to wake up and get things done */
884                 ast_waitfor_n_fd(&timingfd, 1, &timeout, NULL);
885                 ast_timer_ack(timer, 1);
886                 ao2_lock(bridge);
887
888                 /* make sure to detect mixing interval changes if they occur. */
889                 if (bridge->internal_mixing_interval && (bridge->internal_mixing_interval != softmix_data->internal_mixing_interval)) {
890                         softmix_data->internal_mixing_interval = bridge->internal_mixing_interval;
891                         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
892                         update_all_rates = 1; /* if the interval changes, the rates must be adjusted as well just to be notified new interval.*/
893                 }
894         }
895
896         res = 0;
897
898 softmix_cleanup:
899         softmix_translate_helper_destroy(&trans_helper);
900         softmix_mixing_array_destroy(&mixing_array);
901         if (softmix_data) {
902                 ao2_ref(softmix_data, -1);
903         }
904         return res;
905 }
906
907 static struct ast_bridge_technology softmix_bridge = {
908         .name = "softmix",
909         .capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX | AST_BRIDGE_CAPABILITY_THREAD | AST_BRIDGE_CAPABILITY_MULTITHREADED | AST_BRIDGE_CAPABILITY_OPTIMIZE | AST_BRIDGE_CAPABILITY_VIDEO,
910         .preference = AST_BRIDGE_PREFERENCE_LOW,
911         .create = softmix_bridge_create,
912         .destroy = softmix_bridge_destroy,
913         .join = softmix_bridge_join,
914         .leave = softmix_bridge_leave,
915         .write = softmix_bridge_write,
916         .thread = softmix_bridge_thread,
917         .poke = softmix_bridge_poke,
918 };
919
920 static int unload_module(void)
921 {
922         ast_format_cap_destroy(softmix_bridge.format_capabilities);
923         return ast_bridge_technology_unregister(&softmix_bridge);
924 }
925
926 static int load_module(void)
927 {
928         struct ast_format tmp;
929         if (!(softmix_bridge.format_capabilities = ast_format_cap_alloc())) {
930                 return AST_MODULE_LOAD_DECLINE;
931         }
932         ast_format_cap_add(softmix_bridge.format_capabilities, ast_format_set(&tmp, AST_FORMAT_SLINEAR, 0));
933         return ast_bridge_technology_register(&softmix_bridge);
934 }
935
936 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multi-party software based channel mixing");