Fix a crash when a bridge switches from the softmix bridge technology to another.
[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         /*!
104          * \brief TRUE if a channel is talking.
105          *
106          * \note This affects how the channel's audio is mixed back to
107          * it.
108          */
109         unsigned int talking:1;
110         /*! TRUE if the channel provided audio for this mixing interval */
111         unsigned int have_audio:1;
112         /*! Buffer containing final mixed audio from all sources */
113         short final_buf[MAX_DATALEN];
114         /*! Buffer containing only the audio from the channel */
115         short our_buf[MAX_DATALEN];
116         /*! Data pertaining to talker mode for video conferencing */
117         struct video_follow_talker_data video_talker;
118 };
119
120 struct softmix_bridge_data {
121         struct ast_timer *timer;
122         /*! Lock for signaling the mixing thread. */
123         ast_mutex_t lock;
124         /*! Condition, used if we need to wake up the mixing thread. */
125         ast_cond_t cond;
126         /*! Thread handling the mixing */
127         pthread_t thread;
128         unsigned int internal_rate;
129         unsigned int internal_mixing_interval;
130         /*! TRUE if the mixing thread should stop */
131         unsigned int stop:1;
132 };
133
134 struct softmix_stats {
135         /*! Each index represents a sample rate used above the internal rate. */
136         unsigned int sample_rates[16];
137         /*! Each index represents the number of channels using the same index in the sample_rates array.  */
138         unsigned int num_channels[16];
139         /*! the number of channels above the internal sample rate */
140         unsigned int num_above_internal_rate;
141         /*! the number of channels at the internal sample rate */
142         unsigned int num_at_internal_rate;
143         /*! the absolute highest sample rate supported by any channel in the bridge */
144         unsigned int highest_supported_rate;
145         /*! Is the sample rate locked by the bridge, if so what is that rate.*/
146         unsigned int locked_rate;
147 };
148
149 struct softmix_mixing_array {
150         unsigned int max_num_entries;
151         unsigned int used_entries;
152         int16_t **buffers;
153 };
154
155 struct softmix_translate_helper_entry {
156         int num_times_requested; /*!< Once this entry is no longer requested, free the trans_pvt
157                                       and re-init if it was usable. */
158         struct ast_format dst_format; /*!< The destination format for this helper */
159         struct ast_trans_pvt *trans_pvt; /*!< the translator for this slot. */
160         struct ast_frame *out_frame; /*!< The output frame from the last translation */
161         AST_LIST_ENTRY(softmix_translate_helper_entry) entry;
162 };
163
164 struct softmix_translate_helper {
165         struct ast_format slin_src; /*!< the source format expected for all the translators */
166         AST_LIST_HEAD_NOLOCK(, softmix_translate_helper_entry) entries;
167 };
168
169 static struct softmix_translate_helper_entry *softmix_translate_helper_entry_alloc(struct ast_format *dst)
170 {
171         struct softmix_translate_helper_entry *entry;
172         if (!(entry = ast_calloc(1, sizeof(*entry)))) {
173                 return NULL;
174         }
175         ast_format_copy(&entry->dst_format, dst);
176         return entry;
177 }
178
179 static void *softmix_translate_helper_free_entry(struct softmix_translate_helper_entry *entry)
180 {
181         if (entry->trans_pvt) {
182                 ast_translator_free_path(entry->trans_pvt);
183         }
184         if (entry->out_frame) {
185                 ast_frfree(entry->out_frame);
186         }
187         ast_free(entry);
188         return NULL;
189 }
190
191 static void softmix_translate_helper_init(struct softmix_translate_helper *trans_helper, unsigned int sample_rate)
192 {
193         memset(trans_helper, 0, sizeof(*trans_helper));
194         ast_format_set(&trans_helper->slin_src, ast_format_slin_by_rate(sample_rate), 0);
195 }
196
197 static void softmix_translate_helper_destroy(struct softmix_translate_helper *trans_helper)
198 {
199         struct softmix_translate_helper_entry *entry;
200
201         while ((entry = AST_LIST_REMOVE_HEAD(&trans_helper->entries, entry))) {
202                 softmix_translate_helper_free_entry(entry);
203         }
204 }
205
206 static void softmix_translate_helper_change_rate(struct softmix_translate_helper *trans_helper, unsigned int sample_rate)
207 {
208         struct softmix_translate_helper_entry *entry;
209
210         ast_format_set(&trans_helper->slin_src, ast_format_slin_by_rate(sample_rate), 0);
211         AST_LIST_TRAVERSE_SAFE_BEGIN(&trans_helper->entries, entry, entry) {
212                 if (entry->trans_pvt) {
213                         ast_translator_free_path(entry->trans_pvt);
214                         if (!(entry->trans_pvt = ast_translator_build_path(&entry->dst_format, &trans_helper->slin_src))) {
215                                 AST_LIST_REMOVE_CURRENT(entry);
216                                 entry = softmix_translate_helper_free_entry(entry);
217                         }
218                 }
219         }
220         AST_LIST_TRAVERSE_SAFE_END;
221 }
222
223 /*!
224  * \internal
225  * \brief Get the next available audio on the softmix channel's read stream
226  * and determine if it should be mixed out or not on the write stream.
227  *
228  * \retval pointer to buffer containing the exact number of samples requested on success.
229  * \retval NULL if no samples are present
230  */
231 static int16_t *softmix_process_read_audio(struct softmix_channel *sc, unsigned int num_samples)
232 {
233         if ((ast_slinfactory_available(&sc->factory) >= num_samples) &&
234                 ast_slinfactory_read(&sc->factory, sc->our_buf, num_samples)) {
235                 sc->have_audio = 1;
236                 return sc->our_buf;
237         }
238         sc->have_audio = 0;
239         return NULL;
240 }
241
242 /*!
243  * \internal
244  * \brief Process a softmix channel's write audio
245  *
246  * \details This function will remove the channel's talking from its own audio if present and
247  * possibly even do the channel's write translation for it depending on how many other
248  * channels use the same write format.
249  */
250 static void softmix_process_write_audio(struct softmix_translate_helper *trans_helper,
251         struct ast_format *raw_write_fmt,
252         struct softmix_channel *sc)
253 {
254         struct softmix_translate_helper_entry *entry = NULL;
255         int i;
256
257         /* If we provided audio that was not determined to be silence,
258          * then take it out while in slinear format. */
259         if (sc->have_audio && sc->talking) {
260                 for (i = 0; i < sc->write_frame.samples; i++) {
261                         ast_slinear_saturated_subtract(&sc->final_buf[i], &sc->our_buf[i]);
262                 }
263                 /* do not do any special write translate optimization if we had to make
264                  * a special mix for them to remove their own audio. */
265                 return;
266         }
267
268         AST_LIST_TRAVERSE(&trans_helper->entries, entry, entry) {
269                 if (ast_format_cmp(&entry->dst_format, raw_write_fmt) == AST_FORMAT_CMP_EQUAL) {
270                         entry->num_times_requested++;
271                 } else {
272                         continue;
273                 }
274                 if (!entry->trans_pvt && (entry->num_times_requested > 1)) {
275                         entry->trans_pvt = ast_translator_build_path(&entry->dst_format, &trans_helper->slin_src);
276                 }
277                 if (entry->trans_pvt && !entry->out_frame) {
278                         entry->out_frame = ast_translate(entry->trans_pvt, &sc->write_frame, 0);
279                 }
280                 if (entry->out_frame && (entry->out_frame->datalen < MAX_DATALEN)) {
281                         ast_format_copy(&sc->write_frame.subclass.format, &entry->out_frame->subclass.format);
282                         memcpy(sc->final_buf, entry->out_frame->data.ptr, entry->out_frame->datalen);
283                         sc->write_frame.datalen = entry->out_frame->datalen;
284                         sc->write_frame.samples = entry->out_frame->samples;
285                 }
286                 break;
287         }
288
289         /* add new entry into list if this format destination was not matched. */
290         if (!entry && (entry = softmix_translate_helper_entry_alloc(raw_write_fmt))) {
291                 AST_LIST_INSERT_HEAD(&trans_helper->entries, entry, entry);
292         }
293 }
294
295 static void softmix_translate_helper_cleanup(struct softmix_translate_helper *trans_helper)
296 {
297         struct softmix_translate_helper_entry *entry;
298
299         AST_LIST_TRAVERSE(&trans_helper->entries, entry, entry) {
300                 if (entry->out_frame) {
301                         ast_frfree(entry->out_frame);
302                         entry->out_frame = NULL;
303                 }
304                 entry->num_times_requested = 0;
305         }
306 }
307
308 static void set_softmix_bridge_data(int rate, int interval, struct ast_bridge_channel *bridge_channel, int reset)
309 {
310         struct softmix_channel *sc = bridge_channel->tech_pvt;
311         unsigned int channel_read_rate = ast_format_rate(ast_channel_rawreadformat(bridge_channel->chan));
312
313         ast_mutex_lock(&sc->lock);
314         if (reset) {
315                 ast_slinfactory_destroy(&sc->factory);
316                 ast_dsp_free(sc->dsp);
317         }
318         /* Setup read/write frame parameters */
319         sc->write_frame.frametype = AST_FRAME_VOICE;
320         ast_format_set(&sc->write_frame.subclass.format, ast_format_slin_by_rate(rate), 0);
321         sc->write_frame.data.ptr = sc->final_buf;
322         sc->write_frame.datalen = SOFTMIX_DATALEN(rate, interval);
323         sc->write_frame.samples = SOFTMIX_SAMPLES(rate, interval);
324
325         sc->read_frame.frametype = AST_FRAME_VOICE;
326         ast_format_set(&sc->read_frame.subclass.format, ast_format_slin_by_rate(channel_read_rate), 0);
327         sc->read_frame.data.ptr = sc->our_buf;
328         sc->read_frame.datalen = SOFTMIX_DATALEN(channel_read_rate, interval);
329         sc->read_frame.samples = SOFTMIX_SAMPLES(channel_read_rate, interval);
330
331         /* Setup smoother */
332         ast_slinfactory_init_with_format(&sc->factory, &sc->write_frame.subclass.format);
333
334         /* set new read and write formats on channel. */
335         ast_set_read_format(bridge_channel->chan, &sc->read_frame.subclass.format);
336         ast_set_write_format(bridge_channel->chan, &sc->write_frame.subclass.format);
337
338         /* set up new DSP.  This is on the read side only right before the read frame enters the smoother.  */
339         sc->dsp = ast_dsp_new_with_rate(channel_read_rate);
340         /* we want to aggressively detect silence to avoid feedback */
341         if (bridge_channel->tech_args.talking_threshold) {
342                 ast_dsp_set_threshold(sc->dsp, bridge_channel->tech_args.talking_threshold);
343         } else {
344                 ast_dsp_set_threshold(sc->dsp, DEFAULT_SOFTMIX_TALKING_THRESHOLD);
345         }
346
347         ast_mutex_unlock(&sc->lock);
348 }
349
350 /*!
351  * \internal
352  * \brief Poke the mixing thread in case it is waiting for an active channel.
353  * \since 12.0.0
354  *
355  * \param softmix_data Bridge mixing data.
356  *
357  * \return Nothing
358  */
359 static void softmix_poke_thread(struct softmix_bridge_data *softmix_data)
360 {
361         ast_mutex_lock(&softmix_data->lock);
362         ast_cond_signal(&softmix_data->cond);
363         ast_mutex_unlock(&softmix_data->lock);
364 }
365
366 /*! \brief Function called when a channel is unsuspended from the bridge */
367 static void softmix_bridge_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
368 {
369         if (bridge->tech_pvt) {
370                 softmix_poke_thread(bridge->tech_pvt);
371         }
372 }
373
374 /*!
375  * \internal
376  * \brief Indicate a source change to the channel.
377  * \since 12.0.0
378  *
379  * \param bridge_channel Which channel source is changing.
380  *
381  * \return Nothing
382  */
383 static void softmix_src_change(struct ast_bridge_channel *bridge_channel)
384 {
385         ast_bridge_channel_queue_control_data(bridge_channel, AST_CONTROL_SRCCHANGE, NULL, 0);
386 }
387
388 /*! \brief Function called when a channel is joined into the bridge */
389 static int softmix_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
390 {
391         struct softmix_channel *sc;
392         struct softmix_bridge_data *softmix_data;
393
394         softmix_data = bridge->tech_pvt;
395         if (!softmix_data) {
396                 return -1;
397         }
398
399         /* Create a new softmix_channel structure and allocate various things on it */
400         if (!(sc = ast_calloc(1, sizeof(*sc)))) {
401                 return -1;
402         }
403
404         softmix_src_change(bridge_channel);
405
406         /* Can't forget the lock */
407         ast_mutex_init(&sc->lock);
408
409         /* Can't forget to record our pvt structure within the bridged channel structure */
410         bridge_channel->tech_pvt = sc;
411
412         set_softmix_bridge_data(softmix_data->internal_rate,
413                 softmix_data->internal_mixing_interval
414                         ? softmix_data->internal_mixing_interval
415                         : DEFAULT_SOFTMIX_INTERVAL,
416                 bridge_channel, 0);
417
418         softmix_poke_thread(softmix_data);
419         return 0;
420 }
421
422 /*! \brief Function called when a channel leaves the bridge */
423 static void softmix_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
424 {
425         struct softmix_channel *sc = bridge_channel->tech_pvt;
426
427         if (!sc) {
428                 return;
429         }
430         bridge_channel->tech_pvt = NULL;
431
432         softmix_src_change(bridge_channel);
433
434         /* Drop mutex lock */
435         ast_mutex_destroy(&sc->lock);
436
437         /* Drop the factory */
438         ast_slinfactory_destroy(&sc->factory);
439
440         /* Drop the DSP */
441         ast_dsp_free(sc->dsp);
442
443         /* Eep! drop ourselves */
444         ast_free(sc);
445 }
446
447 /*!
448  * \internal
449  * \brief Pass the given frame to everyone else.
450  * \since 12.0.0
451  *
452  * \param bridge What bridge to distribute frame.
453  * \param bridge_channel Channel to optionally not pass frame to. (NULL to pass to everyone)
454  * \param frame Frame to pass.
455  *
456  * \return Nothing
457  */
458 static void softmix_pass_everyone_else(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
459 {
460         struct ast_bridge_channel *cur;
461
462         AST_LIST_TRAVERSE(&bridge->channels, cur, entry) {
463                 if (cur == bridge_channel) {
464                         continue;
465                 }
466                 ast_bridge_channel_queue_frame(cur, frame);
467         }
468 }
469
470 static void softmix_pass_video_top_priority(struct ast_bridge *bridge, struct ast_frame *frame)
471 {
472         struct ast_bridge_channel *cur;
473
474         AST_LIST_TRAVERSE(&bridge->channels, cur, entry) {
475                 if (cur->suspended) {
476                         continue;
477                 }
478                 if (ast_bridge_is_video_src(bridge, cur->chan) == 1) {
479                         ast_bridge_channel_queue_frame(cur, frame);
480                         break;
481                 }
482         }
483 }
484
485 /*!
486  * \internal
487  * \brief Determine what to do with a video frame.
488  * \since 12.0.0
489  *
490  * \param bridge Which bridge is getting the frame
491  * \param bridge_channel Which channel is writing the frame.
492  * \param frame What is being written.
493  *
494  * \return Nothing
495  */
496 static void softmix_bridge_write_video(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
497 {
498         struct softmix_channel *sc;
499         int video_src_priority;
500
501         /* Determine if the video frame should be distributed or not */
502         switch (bridge->video_mode.mode) {
503         case AST_BRIDGE_VIDEO_MODE_NONE:
504                 break;
505         case AST_BRIDGE_VIDEO_MODE_SINGLE_SRC:
506                 video_src_priority = ast_bridge_is_video_src(bridge, bridge_channel->chan);
507                 if (video_src_priority == 1) {
508                         /* Pass to me and everyone else. */
509                         softmix_pass_everyone_else(bridge, NULL, frame);
510                 }
511                 break;
512         case AST_BRIDGE_VIDEO_MODE_TALKER_SRC:
513                 sc = bridge_channel->tech_pvt;
514                 ast_mutex_lock(&sc->lock);
515                 ast_bridge_update_talker_src_video_mode(bridge, bridge_channel->chan,
516                         sc->video_talker.energy_average,
517                         ast_format_get_video_mark(&frame->subclass.format));
518                 ast_mutex_unlock(&sc->lock);
519                 video_src_priority = ast_bridge_is_video_src(bridge, bridge_channel->chan);
520                 if (video_src_priority == 1) {
521                         int num_src = ast_bridge_number_video_src(bridge);
522                         int echo = num_src > 1 ? 0 : 1;
523
524                         softmix_pass_everyone_else(bridge, echo ? NULL : bridge_channel, frame);
525                 } else if (video_src_priority == 2) {
526                         softmix_pass_video_top_priority(bridge, frame);
527                 }
528                 break;
529         }
530 }
531
532 /*!
533  * \internal
534  * \brief Determine what to do with a voice frame.
535  * \since 12.0.0
536  *
537  * \param bridge Which bridge is getting the frame
538  * \param bridge_channel Which channel is writing the frame.
539  * \param frame What is being written.
540  *
541  * \return Nothing
542  */
543 static void softmix_bridge_write_voice(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
544 {
545         struct softmix_channel *sc = bridge_channel->tech_pvt;
546         struct softmix_bridge_data *softmix_data = bridge->tech_pvt;
547         int totalsilence = 0;
548         int cur_energy = 0;
549         int silence_threshold = bridge_channel->tech_args.silence_threshold ?
550                 bridge_channel->tech_args.silence_threshold :
551                 DEFAULT_SOFTMIX_SILENCE_THRESHOLD;
552         char update_talking = -1;  /* if this is set to 0 or 1, tell the bridge that the channel has started or stopped talking. */
553
554         /* Write the frame into the conference */
555         ast_mutex_lock(&sc->lock);
556         ast_dsp_silence_with_energy(sc->dsp, frame, &totalsilence, &cur_energy);
557
558         if (bridge->video_mode.mode == AST_BRIDGE_VIDEO_MODE_TALKER_SRC) {
559                 int cur_slot = sc->video_talker.energy_history_cur_slot;
560
561                 sc->video_talker.energy_accum -= sc->video_talker.energy_history[cur_slot];
562                 sc->video_talker.energy_accum += cur_energy;
563                 sc->video_talker.energy_history[cur_slot] = cur_energy;
564                 sc->video_talker.energy_average = sc->video_talker.energy_accum / DEFAULT_ENERGY_HISTORY_LEN;
565                 sc->video_talker.energy_history_cur_slot++;
566                 if (sc->video_talker.energy_history_cur_slot == DEFAULT_ENERGY_HISTORY_LEN) {
567                         sc->video_talker.energy_history_cur_slot = 0; /* wrap around */
568                 }
569         }
570
571         if (totalsilence < silence_threshold) {
572                 if (!sc->talking) {
573                         update_talking = 1;
574                 }
575                 sc->talking = 1; /* tell the write process we have audio to be mixed out */
576         } else {
577                 if (sc->talking) {
578                         update_talking = 0;
579                 }
580                 sc->talking = 0;
581         }
582
583         /* Before adding audio in, make sure we haven't fallen behind. If audio has fallen
584          * behind 4 times the amount of samples mixed on every iteration of the mixer, Re-sync
585          * the audio by flushing the buffer before adding new audio in. */
586         if (ast_slinfactory_available(&sc->factory) > (4 * SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval))) {
587                 ast_slinfactory_flush(&sc->factory);
588         }
589
590         /* If a frame was provided add it to the smoother, unless drop silence is enabled and this frame
591          * is not determined to be talking. */
592         if (!(bridge_channel->tech_args.drop_silence && !sc->talking) &&
593                 (frame->frametype == AST_FRAME_VOICE && ast_format_is_slinear(&frame->subclass.format))) {
594                 ast_slinfactory_feed(&sc->factory, frame);
595         }
596
597         /* Alllll done */
598         ast_mutex_unlock(&sc->lock);
599
600         if (update_talking != -1) {
601                 ast_bridge_notify_talking(bridge_channel, update_talking);
602         }
603 }
604
605 /*!
606  * \internal
607  * \brief Determine what to do with a control frame.
608  * \since 12.0.0
609  *
610  * \param bridge Which bridge is getting the frame
611  * \param bridge_channel Which channel is writing the frame.
612  * \param frame What is being written.
613  *
614  * \return Nothing
615  */
616 static void softmix_bridge_write_control(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
617 {
618 /* BUGBUG need to look at channel roles to determine what to do with control frame. */
619         /*! \todo BUGBUG softmix_bridge_write_control() not written */
620 }
621
622 /*!
623  * \internal
624  * \brief Determine what to do with a frame written into the bridge.
625  * \since 12.0.0
626  *
627  * \param bridge Which bridge is getting the frame
628  * \param bridge_channel Which channel is writing the frame.
629  * \param frame What is being written.
630  *
631  * \retval 0 on success
632  * \retval -1 on failure
633  *
634  * \note On entry, bridge is already locked.
635  */
636 static int softmix_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
637 {
638         int res = 0;
639
640         if (!bridge->tech_pvt || !bridge_channel->tech_pvt) {
641                 return -1;
642         }
643
644         switch (frame->frametype) {
645         case AST_FRAME_DTMF_BEGIN:
646         case AST_FRAME_DTMF_END:
647                 softmix_pass_everyone_else(bridge, bridge_channel, frame);
648                 break;
649         case AST_FRAME_VOICE:
650                 softmix_bridge_write_voice(bridge, bridge_channel, frame);
651                 break;
652         case AST_FRAME_VIDEO:
653                 softmix_bridge_write_video(bridge, bridge_channel, frame);
654                 break;
655         case AST_FRAME_CONTROL:
656                 softmix_bridge_write_control(bridge, bridge_channel, frame);
657                 break;
658         case AST_FRAME_BRIDGE_ACTION:
659                 softmix_pass_everyone_else(bridge, bridge_channel, frame);
660                 break;
661         default:
662                 ast_debug(3, "Frame type %d unsupported\n", frame->frametype);
663                 res = -1;
664                 break;
665         }
666
667         return res;
668 }
669
670 static void gather_softmix_stats(struct softmix_stats *stats,
671         const struct softmix_bridge_data *softmix_data,
672         struct ast_bridge_channel *bridge_channel)
673 {
674         int channel_native_rate;
675         int i;
676         /* Gather stats about channel sample rates. */
677         channel_native_rate = MAX(ast_format_rate(ast_channel_rawwriteformat(bridge_channel->chan)),
678                 ast_format_rate(ast_channel_rawreadformat(bridge_channel->chan)));
679
680         if (channel_native_rate > stats->highest_supported_rate) {
681                 stats->highest_supported_rate = channel_native_rate;
682         }
683         if (channel_native_rate > softmix_data->internal_rate) {
684                 for (i = 0; i < ARRAY_LEN(stats->sample_rates); i++) {
685                         if (stats->sample_rates[i] == channel_native_rate) {
686                                 stats->num_channels[i]++;
687                                 break;
688                         } else if (!stats->sample_rates[i]) {
689                                 stats->sample_rates[i] = channel_native_rate;
690                                 stats->num_channels[i]++;
691                                 break;
692                         }
693                 }
694                 stats->num_above_internal_rate++;
695         } else if (channel_native_rate == softmix_data->internal_rate) {
696                 stats->num_at_internal_rate++;
697         }
698 }
699 /*!
700  * \internal
701  * \brief Analyse mixing statistics and change bridges internal rate
702  * if necessary.
703  *
704  * \retval 0, no changes to internal rate
705  * \ratval 1, internal rate was changed, update all the channels on the next mixing iteration.
706  */
707 static unsigned int analyse_softmix_stats(struct softmix_stats *stats, struct softmix_bridge_data *softmix_data)
708 {
709         int i;
710         /* Re-adjust the internal bridge sample rate if
711          * 1. The bridge's internal sample rate is locked in at a sample
712          *    rate other than the current sample rate being used.
713          * 2. two or more channels support a higher sample rate
714          * 3. no channels support the current sample rate or a higher rate
715          */
716         if (stats->locked_rate) {
717                 /* if the rate is locked by the bridge, only update it if it differs
718                  * from the current rate we are using. */
719                 if (softmix_data->internal_rate != stats->locked_rate) {
720                         softmix_data->internal_rate = stats->locked_rate;
721                         ast_debug(1, "Bridge is locked in at sample rate %d\n",
722                                 softmix_data->internal_rate);
723                         return 1;
724                 }
725         } else if (stats->num_above_internal_rate >= 2) {
726                 /* the highest rate is just used as a starting point */
727                 unsigned int best_rate = stats->highest_supported_rate;
728                 int best_index = -1;
729
730                 for (i = 0; i < ARRAY_LEN(stats->num_channels); i++) {
731                         if (stats->num_channels[i]) {
732                                 break;
733                         }
734                         /* best_rate starts out being the first sample rate
735                          * greater than the internal sample rate that 2 or
736                          * more channels support. */
737                         if (stats->num_channels[i] >= 2 && (best_index == -1)) {
738                                 best_rate = stats->sample_rates[i];
739                                 best_index = i;
740                         /* If it has been detected that multiple rates above
741                          * the internal rate are present, compare those rates
742                          * to each other and pick the highest one two or more
743                          * channels support. */
744                         } else if (((best_index != -1) &&
745                                 (stats->num_channels[i] >= 2) &&
746                                 (stats->sample_rates[best_index] < stats->sample_rates[i]))) {
747                                 best_rate = stats->sample_rates[i];
748                                 best_index = i;
749                         /* It is possible that multiple channels exist with native sample
750                          * rates above the internal sample rate, but none of those channels
751                          * have the same rate in common.  In this case, the lowest sample
752                          * rate among those channels is picked. Over time as additional
753                          * statistic runs are made the internal sample rate number will
754                          * adjust to the most optimal sample rate, but it may take multiple
755                          * iterations. */
756                         } else if (best_index == -1) {
757                                 best_rate = MIN(best_rate, stats->sample_rates[i]);
758                         }
759                 }
760
761                 ast_debug(1, "Bridge changed from %d To %d\n",
762                         softmix_data->internal_rate, best_rate);
763                 softmix_data->internal_rate = best_rate;
764                 return 1;
765         } else if (!stats->num_at_internal_rate && !stats->num_above_internal_rate) {
766                 /* In this case, the highest supported rate is actually lower than the internal rate */
767                 softmix_data->internal_rate = stats->highest_supported_rate;
768                 ast_debug(1, "Bridge changed from %d to %d\n",
769                         softmix_data->internal_rate, stats->highest_supported_rate);
770                 return 1;
771         }
772         return 0;
773 }
774
775 static int softmix_mixing_array_init(struct softmix_mixing_array *mixing_array, unsigned int starting_num_entries)
776 {
777         memset(mixing_array, 0, sizeof(*mixing_array));
778         mixing_array->max_num_entries = starting_num_entries;
779         if (!(mixing_array->buffers = ast_calloc(mixing_array->max_num_entries, sizeof(int16_t *)))) {
780                 ast_log(LOG_NOTICE, "Failed to allocate softmix mixing structure.\n");
781                 return -1;
782         }
783         return 0;
784 }
785
786 static void softmix_mixing_array_destroy(struct softmix_mixing_array *mixing_array)
787 {
788         ast_free(mixing_array->buffers);
789 }
790
791 static int softmix_mixing_array_grow(struct softmix_mixing_array *mixing_array, unsigned int num_entries)
792 {
793         int16_t **tmp;
794         /* give it some room to grow since memory is cheap but allocations can be expensive */
795         mixing_array->max_num_entries = num_entries;
796         if (!(tmp = ast_realloc(mixing_array->buffers, (mixing_array->max_num_entries * sizeof(int16_t *))))) {
797                 ast_log(LOG_NOTICE, "Failed to re-allocate softmix mixing structure.\n");
798                 return -1;
799         }
800         mixing_array->buffers = tmp;
801         return 0;
802 }
803
804 /*!
805  * \brief Mixing loop.
806  *
807  * \retval 0 on success
808  * \retval -1 on failure
809  */
810 static int softmix_mixing_loop(struct ast_bridge *bridge)
811 {
812         struct softmix_stats stats = { { 0 }, };
813         struct softmix_mixing_array mixing_array;
814         struct softmix_bridge_data *softmix_data = bridge->tech_pvt;
815         struct ast_timer *timer;
816         struct softmix_translate_helper trans_helper;
817         int16_t buf[MAX_DATALEN];
818         unsigned int stat_iteration_counter = 0; /* counts down, gather stats at zero and reset. */
819         int timingfd;
820         int update_all_rates = 0; /* set this when the internal sample rate has changed */
821         unsigned int idx;
822         unsigned int x;
823         int res = -1;
824
825         timer = softmix_data->timer;
826         timingfd = ast_timer_fd(timer);
827         softmix_translate_helper_init(&trans_helper, softmix_data->internal_rate);
828         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
829
830         /* Give the mixing array room to grow, memory is cheap but allocations are expensive. */
831         if (softmix_mixing_array_init(&mixing_array, bridge->num_channels + 10)) {
832                 goto softmix_cleanup;
833         }
834
835         while (!softmix_data->stop && bridge->num_active) {
836                 struct ast_bridge_channel *bridge_channel;
837                 int timeout = -1;
838                 enum ast_format_id cur_slin_id = ast_format_slin_by_rate(softmix_data->internal_rate);
839                 unsigned int softmix_samples = SOFTMIX_SAMPLES(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
840                 unsigned int softmix_datalen = SOFTMIX_DATALEN(softmix_data->internal_rate, softmix_data->internal_mixing_interval);
841
842                 if (softmix_datalen > MAX_DATALEN) {
843                         /* This should NEVER happen, but if it does we need to know about it. Almost
844                          * all the memcpys used during this process depend on this assumption.  Rather
845                          * than checking this over and over again through out the code, this single
846                          * verification is done on each iteration. */
847                         ast_log(LOG_WARNING,
848                                 "Bridge %s: Conference mixing error, requested mixing length greater than mixing buffer.\n",
849                                 bridge->uniqueid);
850                         goto softmix_cleanup;
851                 }
852
853                 /* Grow the mixing array buffer as participants are added. */
854                 if (mixing_array.max_num_entries < bridge->num_channels
855                         && softmix_mixing_array_grow(&mixing_array, bridge->num_channels + 5)) {
856                         goto softmix_cleanup;
857                 }
858
859                 /* init the number of buffers stored in the mixing array to 0.
860                  * As buffers are added for mixing, this number is incremented. */
861                 mixing_array.used_entries = 0;
862
863                 /* These variables help determine if a rate change is required */
864                 if (!stat_iteration_counter) {
865                         memset(&stats, 0, sizeof(stats));
866                         stats.locked_rate = bridge->internal_sample_rate;
867                 }
868
869                 /* If the sample rate has changed, update the translator helper */
870                 if (update_all_rates) {
871                         softmix_translate_helper_change_rate(&trans_helper, softmix_data->internal_rate);
872                 }
873
874                 /* Go through pulling audio from each factory that has it available */
875                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
876                         struct softmix_channel *sc = bridge_channel->tech_pvt;
877
878                         /* Update the sample rate to match the bridge's native sample rate if necessary. */
879                         if (update_all_rates) {
880                                 set_softmix_bridge_data(softmix_data->internal_rate, softmix_data->internal_mixing_interval, bridge_channel, 1);
881                         }
882
883                         /* If stat_iteration_counter is 0, then collect statistics during this mixing interation */
884                         if (!stat_iteration_counter) {
885                                 gather_softmix_stats(&stats, softmix_data, bridge_channel);
886                         }
887
888                         /* if the channel is suspended, don't check for audio, but still gather stats */
889                         if (bridge_channel->suspended) {
890                                 continue;
891                         }
892
893                         /* Try to get audio from the factory if available */
894                         ast_mutex_lock(&sc->lock);
895                         if ((mixing_array.buffers[mixing_array.used_entries] = softmix_process_read_audio(sc, softmix_samples))) {
896                                 mixing_array.used_entries++;
897                         }
898                         ast_mutex_unlock(&sc->lock);
899                 }
900
901                 /* mix it like crazy */
902                 memset(buf, 0, softmix_datalen);
903                 for (idx = 0; idx < mixing_array.used_entries; ++idx) {
904                         for (x = 0; x < softmix_samples; ++x) {
905                                 ast_slinear_saturated_add(buf + x, mixing_array.buffers[idx] + x);
906                         }
907                 }
908
909                 /* Next step go through removing the channel's own audio and creating a good frame... */
910                 AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
911                         struct softmix_channel *sc = bridge_channel->tech_pvt;
912
913                         if (bridge_channel->suspended) {
914                                 continue;
915                         }
916
917                         ast_mutex_lock(&sc->lock);
918
919                         /* Make SLINEAR write frame from local buffer */
920                         if (sc->write_frame.subclass.format.id != cur_slin_id) {
921                                 ast_format_set(&sc->write_frame.subclass.format, cur_slin_id, 0);
922                         }
923                         sc->write_frame.datalen = softmix_datalen;
924                         sc->write_frame.samples = softmix_samples;
925                         memcpy(sc->final_buf, buf, softmix_datalen);
926
927                         /* process the softmix channel's new write audio */
928                         softmix_process_write_audio(&trans_helper, ast_channel_rawwriteformat(bridge_channel->chan), sc);
929
930                         ast_mutex_unlock(&sc->lock);
931
932                         /* A frame is now ready for the channel. */
933                         ast_bridge_channel_queue_frame(bridge_channel, &sc->write_frame);
934                 }
935
936                 update_all_rates = 0;
937                 if (!stat_iteration_counter) {
938                         update_all_rates = analyse_softmix_stats(&stats, softmix_data);
939                         stat_iteration_counter = SOFTMIX_STAT_INTERVAL;
940                 }
941                 stat_iteration_counter--;
942
943                 ast_bridge_unlock(bridge);
944                 /* cleanup any translation frame data from the previous mixing iteration. */
945                 softmix_translate_helper_cleanup(&trans_helper);
946                 /* Wait for the timing source to tell us to wake up and get things done */
947                 ast_waitfor_n_fd(&timingfd, 1, &timeout, NULL);
948                 if (ast_timer_ack(timer, 1) < 0) {
949                         ast_log(LOG_ERROR, "Bridge %s: Failed to acknowledge timer in softmix.\n",
950                                 bridge->uniqueid);
951                         ast_bridge_lock(bridge);
952                         goto softmix_cleanup;
953                 }
954                 ast_bridge_lock(bridge);
955
956                 /* make sure to detect mixing interval changes if they occur. */
957                 if (bridge->internal_mixing_interval && (bridge->internal_mixing_interval != softmix_data->internal_mixing_interval)) {
958                         softmix_data->internal_mixing_interval = bridge->internal_mixing_interval;
959                         ast_timer_set_rate(timer, (1000 / softmix_data->internal_mixing_interval));
960                         update_all_rates = 1; /* if the interval changes, the rates must be adjusted as well just to be notified new interval.*/
961                 }
962         }
963
964         res = 0;
965
966 softmix_cleanup:
967         softmix_translate_helper_destroy(&trans_helper);
968         softmix_mixing_array_destroy(&mixing_array);
969         return res;
970 }
971
972 /*!
973  * \internal
974  * \brief Mixing thread.
975  * \since 12.0.0
976  *
977  * \note The thread does not have its own reference to the
978  * bridge.  The lifetime of the thread is tied to the lifetime
979  * of the mixing technology association with the bridge.
980  */
981 static void *softmix_mixing_thread(void *data)
982 {
983         struct ast_bridge *bridge = data;
984         struct softmix_bridge_data *softmix_data;
985
986         ast_bridge_lock(bridge);
987         if (bridge->callid) {
988                 ast_callid_threadassoc_add(bridge->callid);
989         }
990
991         ast_debug(1, "Bridge %s: starting mixing thread\n", bridge->uniqueid);
992
993         softmix_data = bridge->tech_pvt;
994         while (!softmix_data->stop) {
995                 if (!bridge->num_active) {
996                         /* Wait for something to happen to the bridge. */
997                         ast_bridge_unlock(bridge);
998                         ast_mutex_lock(&softmix_data->lock);
999                         if (!softmix_data->stop) {
1000                                 ast_cond_wait(&softmix_data->cond, &softmix_data->lock);
1001                         }
1002                         ast_mutex_unlock(&softmix_data->lock);
1003                         ast_bridge_lock(bridge);
1004                         continue;
1005                 }
1006
1007                 if (softmix_mixing_loop(bridge)) {
1008                         /*
1009                          * A mixing error occurred.  Sleep and try again later so we
1010                          * won't flood the logs.
1011                          */
1012                         ast_bridge_unlock(bridge);
1013                         sleep(1);
1014                         ast_bridge_lock(bridge);
1015                 }
1016         }
1017
1018         ast_bridge_unlock(bridge);
1019
1020         ast_debug(1, "Bridge %s: stopping mixing thread\n", bridge->uniqueid);
1021
1022         return NULL;
1023 }
1024
1025 static void softmix_bridge_data_destroy(struct softmix_bridge_data *softmix_data)
1026 {
1027         if (softmix_data->timer) {
1028                 ast_timer_close(softmix_data->timer);
1029                 softmix_data->timer = NULL;
1030         }
1031         ast_mutex_destroy(&softmix_data->lock);
1032         ast_free(softmix_data);
1033 }
1034
1035 /*! \brief Function called when a bridge is created */
1036 static int softmix_bridge_create(struct ast_bridge *bridge)
1037 {
1038         struct softmix_bridge_data *softmix_data;
1039
1040         softmix_data = ast_calloc(1, sizeof(*softmix_data));
1041         if (!softmix_data) {
1042                 return -1;
1043         }
1044         ast_mutex_init(&softmix_data->lock);
1045         softmix_data->timer = ast_timer_open();
1046         if (!softmix_data->timer) {
1047                 softmix_bridge_data_destroy(softmix_data);
1048                 return -1;
1049         }
1050         /* start at 8khz, let it grow from there */
1051         softmix_data->internal_rate = 8000;
1052         softmix_data->internal_mixing_interval = DEFAULT_SOFTMIX_INTERVAL;
1053
1054         bridge->tech_pvt = softmix_data;
1055
1056         /* Start the mixing thread. */
1057         if (ast_pthread_create(&softmix_data->thread, NULL, softmix_mixing_thread, bridge)) {
1058                 softmix_data->thread = AST_PTHREADT_NULL;
1059                 softmix_bridge_data_destroy(softmix_data);
1060                 bridge->tech_pvt = NULL;
1061                 return -1;
1062         }
1063
1064         return 0;
1065 }
1066
1067 /*!
1068  * \internal
1069  * \brief Request the softmix mixing thread stop.
1070  * \since 12.0.0
1071  *
1072  * \param bridge Which bridge is being stopped.
1073  *
1074  * \return Nothing
1075  */
1076 static void softmix_bridge_stop(struct ast_bridge *bridge)
1077 {
1078         struct softmix_bridge_data *softmix_data;
1079
1080         softmix_data = bridge->tech_pvt;
1081         if (!softmix_data) {
1082                 return;
1083         }
1084
1085         ast_mutex_lock(&softmix_data->lock);
1086         softmix_data->stop = 1;
1087         ast_mutex_unlock(&softmix_data->lock);
1088 }
1089
1090 /*! \brief Function called when a bridge is destroyed */
1091 static void softmix_bridge_destroy(struct ast_bridge *bridge)
1092 {
1093         struct softmix_bridge_data *softmix_data;
1094         pthread_t thread;
1095
1096         softmix_data = bridge->tech_pvt;
1097         if (!softmix_data) {
1098                 return;
1099         }
1100
1101         /* Stop the mixing thread. */
1102         ast_mutex_lock(&softmix_data->lock);
1103         softmix_data->stop = 1;
1104         ast_cond_signal(&softmix_data->cond);
1105         thread = softmix_data->thread;
1106         softmix_data->thread = AST_PTHREADT_NULL;
1107         ast_mutex_unlock(&softmix_data->lock);
1108         if (thread != AST_PTHREADT_NULL) {
1109                 ast_debug(1, "Bridge %s: Waiting for mixing thread to die.\n", bridge->uniqueid);
1110                 pthread_join(thread, NULL);
1111         }
1112
1113         softmix_bridge_data_destroy(softmix_data);
1114         bridge->tech_pvt = NULL;
1115 }
1116
1117 static struct ast_bridge_technology softmix_bridge = {
1118         .name = "softmix",
1119         .capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX,
1120         .preference = AST_BRIDGE_PREFERENCE_BASE_MULTIMIX,
1121         .create = softmix_bridge_create,
1122         .stop = softmix_bridge_stop,
1123         .destroy = softmix_bridge_destroy,
1124         .join = softmix_bridge_join,
1125         .leave = softmix_bridge_leave,
1126         .unsuspend = softmix_bridge_unsuspend,
1127         .write = softmix_bridge_write,
1128 };
1129
1130 static int unload_module(void)
1131 {
1132         ast_format_cap_destroy(softmix_bridge.format_capabilities);
1133         return ast_bridge_technology_unregister(&softmix_bridge);
1134 }
1135
1136 static int load_module(void)
1137 {
1138         struct ast_format tmp;
1139         if (!(softmix_bridge.format_capabilities = ast_format_cap_alloc())) {
1140                 return AST_MODULE_LOAD_DECLINE;
1141         }
1142         ast_format_cap_add(softmix_bridge.format_capabilities, ast_format_set(&tmp, AST_FORMAT_SLINEAR, 0));
1143         return ast_bridge_technology_register(&softmix_bridge);
1144 }
1145
1146 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multi-party software based channel mixing");