main/jitterbuf.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2004-2005, Horizon Wimba, Inc.
   5  *
   6  * Contributors:
   7  * Steve Kann <stevek@stevek.com>
   8  *
   9  * A license has been granted to Digium (via disclaimer) for the use of
  10  * this code.
  11  *
  12  * See http://www.asterisk.org for more information about
  13  * the Asterisk project. Please do not directly contact
  14  * any of the maintainers of this project for assistance;
  15  * the project provides a web site, mailing lists and IRC
  16  * channels for your use.
  17  *
  18  * This program is free software, distributed under the terms of
  19  * the GNU General Public License Version 2. See the LICENSE file
  20  * at the top of the source tree.
  21  */
  22
  23 /*! \file
  24  *
  25  * \brief jitterbuf: an application-independent jitterbuffer
  26  * \author Steve Kann <stevek@stevek.com>
  27  *
  28  */
  29
  30 #include "asterisk.h"
  31
  32 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  33
  34 #include "jitterbuf.h"
  35 #include "asterisk/utils.h"
  36
  37 /*! define these here, just for ancient compiler systems */
  38 #define JB_LONGMAX 2147483647L
  39 #define JB_LONGMIN (-JB_LONGMAX - 1L)
  40
  41 #define jb_warn(...) (warnf ? warnf(__VA_ARGS__) : (void)0)
  42 #define jb_err(...) (errf ? errf(__VA_ARGS__) : (void)0)
  43 #define jb_dbg(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)
  44
  45 #ifdef DEEP_DEBUG
  46 #define jb_dbg2(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)
  47 #else
  48 #define jb_dbg2(...) ((void)0)
  49 #endif
  50
  51 static jb_output_function_t warnf, errf, dbgf;
  52
  53 void jb_setoutput(jb_output_function_t err, jb_output_function_t warn, jb_output_function_t dbg)
  54 {
  55         errf = err;
  56         warnf = warn;
  57         dbgf = dbg;
  58 }
  59
  60 static void increment_losspct(jitterbuf *jb)
  61 {
  62         jb->info.losspct = (100000 + 499 * jb->info.losspct)/500;
  63 }
  64
  65 static void decrement_losspct(jitterbuf *jb)
  66 {
  67         jb->info.losspct = (499 * jb->info.losspct)/500;
  68 }
  69
  70 void jb_reset(jitterbuf *jb)
  71 {
  72         /* only save settings */
  73         jb_conf s = jb->info.conf;
  74         memset(jb, 0, sizeof(*jb));
  75         jb->info.conf = s;
  76
  77         /* initialize length, using the default value */
  78         jb->info.current = jb->info.target = jb->info.conf.target_extra = JB_TARGET_EXTRA;
  79         jb->info.silence_begin_ts = -1;
  80 }
  81
  82 jitterbuf * jb_new()
  83 {
  84         jitterbuf *jb;
  85
  86         if (!(jb = ast_malloc(sizeof(*jb))))
  87                 return NULL;
  88
  89         jb_reset(jb);
  90
  91         jb_dbg2("jb_new() = %x\n", jb);
  92         return jb;
  93 }
  94
  95 void jb_destroy(jitterbuf *jb)
  96 {
  97         jb_frame *frame;
  98         jb_dbg2("jb_destroy(%x)\n", jb);
  99
 100         /* free all the frames on the "free list" */
 101         frame = jb->free;
 102         while (frame != NULL) {
 103                 jb_frame *next = frame->next;
 104                 ast_free(frame);
 105                 frame = next;
 106         }
 107
 108         /* free ourselves! */
 109         ast_free(jb);
 110 }
 111
 112
 113
 114 #if 0
 115 static int longcmp(const void *a, const void *b)
 116 {
 117         return *(long *)a - *(long *)b;
 118 }
 119 #endif
 120
 121 /*!     \brief simple history manipulation
 122         \note maybe later we can make the history buckets variable size, or something? */
 123 /* drop parameter determines whether we will drop outliers to minimize
 124  * delay */
 125 static int history_put(jitterbuf *jb, long ts, long now, long ms)
 126 {
 127         long delay = now - (ts - jb->info.resync_offset);
 128         long threshold = 2 * jb->info.jitter + jb->info.conf.resync_threshold;
 129         long kicked;
 130
 131         /* don't add special/negative times to history */
 132         if (ts <= 0)
 133                 return 0;
 134
 135         /* check for drastic change in delay */
 136         if (jb->info.conf.resync_threshold != -1) {
 137                 if (abs(delay - jb->info.last_delay) > threshold) {
 138                         jb->info.cnt_delay_discont++;
 139                         if (jb->info.cnt_delay_discont > 3) {
 140                                 /* resync the jitterbuffer */
 141                                 jb->info.cnt_delay_discont = 0;
 142                                 jb->hist_ptr = 0;
 143                                 jb->hist_maxbuf_valid = 0;
 144
 145                                 jb_warn("Resyncing the jb. last_delay %ld, this delay %ld, threshold %ld, new offset %ld\n", jb->info.last_delay, delay, threshold, ts - now);
 146                                 jb->info.resync_offset = ts - now;
 147                                 jb->info.last_delay = delay = 0; /* after resync, frame is right on time */
 148                         } else {
 149                                 return -1;
 150                         }
 151                 } else {
 152                         jb->info.last_delay = delay;
 153                         jb->info.cnt_delay_discont = 0;
 154                 }
 155         }
 156
 157         kicked = jb->history[jb->hist_ptr % JB_HISTORY_SZ];
 158
 159         jb->history[(jb->hist_ptr++) % JB_HISTORY_SZ] = delay;
 160
 161         /* optimization; the max/min buffers don't need to be recalculated, if this packet's
 162          * entry doesn't change them.  This happens if this packet is not involved, _and_ any packet
 163          * that got kicked out of the history is also not involved
 164          * We do a number of comparisons, but it's probably still worthwhile, because it will usually
 165          * succeed, and should be a lot faster than going through all 500 packets in history */
 166         if (!jb->hist_maxbuf_valid)
 167                 return 0;
 168
 169         /* don't do this until we've filled history
 170          * (reduces some edge cases below) */
 171         if (jb->hist_ptr < JB_HISTORY_SZ)
 172                 goto invalidate;
 173
 174         /* if the new delay would go into min */
 175         if (delay < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
 176                 goto invalidate;
 177
 178         /* or max.. */
 179         if (delay > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
 180                 goto invalidate;
 181
 182         /* or the kicked delay would be in min */
 183         if (kicked <= jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
 184                 goto invalidate;
 185
 186         if (kicked >= jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
 187                 goto invalidate;
 188
 189         /* if we got here, we don't need to invalidate, 'cause this delay didn't
 190          * affect things */
 191         return 0;
 192         /* end optimization */
 193
 194
 195 invalidate:
 196         jb->hist_maxbuf_valid = 0;
 197         return 0;
 198 }
 199
 200 static void history_calc_maxbuf(jitterbuf *jb)
 201 {
 202         int i,j;
 203
 204         if (jb->hist_ptr == 0)
 205                 return;
 206
 207
 208         /* initialize maxbuf/minbuf to the latest value */
 209         for (i=0;i<JB_HISTORY_MAXBUF_SZ;i++) {
 210 /*
 211  * jb->hist_maxbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
 212  * jb->hist_minbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
 213  */
 214                 jb->hist_maxbuf[i] = JB_LONGMIN;
 215                 jb->hist_minbuf[i] = JB_LONGMAX;
 216         }
 217
 218         /* use insertion sort to populate maxbuf */
 219         /* we want it to be the top "n" values, in order */
 220
 221         /* start at the beginning, or JB_HISTORY_SZ frames ago */
 222         i = (jb->hist_ptr > JB_HISTORY_SZ) ? (jb->hist_ptr - JB_HISTORY_SZ) : 0;
 223
 224         for (;i<jb->hist_ptr;i++) {
 225                 long toins = jb->history[i % JB_HISTORY_SZ];
 226
 227                 /* if the maxbuf should get this */
 228                 if (toins > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])  {
 229
 230                         /* insertion-sort it into the maxbuf */
 231                         for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
 232                                 /* found where it fits */
 233                                 if (toins > jb->hist_maxbuf[j]) {
 234                                         /* move over */
 235                                         memmove(jb->hist_maxbuf + j + 1, jb->hist_maxbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_maxbuf[0]));
 236                                         /* insert */
 237                                         jb->hist_maxbuf[j] = toins;
 238
 239                                         break;
 240                                 }
 241                         }
 242                 }
 243
 244                 /* if the minbuf should get this */
 245                 if (toins < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])  {
 246
 247                         /* insertion-sort it into the maxbuf */
 248                         for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
 249                                 /* found where it fits */
 250                                 if (toins < jb->hist_minbuf[j]) {
 251                                         /* move over */
 252                                         memmove(jb->hist_minbuf + j + 1, jb->hist_minbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_minbuf[0]));
 253                                         /* insert */
 254                                         jb->hist_minbuf[j] = toins;
 255
 256                                         break;
 257                                 }
 258                         }
 259                 }
 260
 261                 if (0) {
 262                         int k;
 263                         fprintf(stderr, "toins = %ld\n", toins);
 264                         fprintf(stderr, "maxbuf =");
 265                         for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
 266                                 fprintf(stderr, "%ld ", jb->hist_maxbuf[k]);
 267                         fprintf(stderr, "\nminbuf =");
 268                         for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
 269                                 fprintf(stderr, "%ld ", jb->hist_minbuf[k]);
 270                         fprintf(stderr, "\n");
 271                 }
 272         }
 273
 274         jb->hist_maxbuf_valid = 1;
 275 }
 276
 277 static void history_get(jitterbuf *jb)
 278 {
 279         long max, min, jitter;
 280         int idx;
 281         int count;
 282
 283         if (!jb->hist_maxbuf_valid)
 284                 history_calc_maxbuf(jb);
 285
 286         /* count is how many items in history we're examining */
 287         count = (jb->hist_ptr < JB_HISTORY_SZ) ? jb->hist_ptr : JB_HISTORY_SZ;
 288
 289         /* idx is the "n"ths highest/lowest that we'll look for */
 290         idx = count * JB_HISTORY_DROPPCT / 100;
 291
 292         /* sanity checks for idx */
 293         if (idx > (JB_HISTORY_MAXBUF_SZ - 1))
 294                 idx = JB_HISTORY_MAXBUF_SZ - 1;
 295
 296         if (idx < 0) {
 297                 jb->info.min = 0;
 298                 jb->info.jitter = 0;
 299                 return;
 300         }
 301
 302         max = jb->hist_maxbuf[idx];
 303         min = jb->hist_minbuf[idx];
 304
 305         jitter = max - min;
 306
 307         /* these debug stmts compare the difference between looking at the absolute jitter, and the
 308          * values we get by throwing away the outliers */
 309         /*
 310         fprintf(stderr, "[%d] min=%d, max=%d, jitter=%d\n", index, min, max, jitter);
 311         fprintf(stderr, "[%d] min=%d, max=%d, jitter=%d\n", 0, jb->hist_minbuf[0], jb->hist_maxbuf[0], jb->hist_maxbuf[0]-jb->hist_minbuf[0]);
 312         */
 313
 314         jb->info.min = min;
 315         jb->info.jitter = jitter;
 316 }
 317
 318 /* returns 1 if frame was inserted into head of queue, 0 otherwise */
 319 static int queue_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts)
 320 {
 321         jb_frame *frame;
 322         jb_frame *p;
 323         int head = 0;
 324         long resync_ts = ts - jb->info.resync_offset;
 325
 326         if ((frame = jb->free)) {
 327                 jb->free = frame->next;
 328         } else if (!(frame = ast_malloc(sizeof(*frame)))) {
 329                 jb_err("cannot allocate frame\n");
 330                 return 0;
 331         }
 332
 333         jb->info.frames_cur++;
 334
 335         frame->data = data;
 336         frame->ts = resync_ts;
 337         frame->ms = ms;
 338         frame->type = type;
 339
 340         /*
 341          * frames are a circular list, jb-frames points to to the lowest ts,
 342          * jb->frames->prev points to the highest ts
 343          */
 344
 345         if (!jb->frames) {  /* queue is empty */
 346                 jb->frames = frame;
 347                 frame->next = frame;
 348                 frame->prev = frame;
 349                 head = 1;
 350         } else if (resync_ts < jb->frames->ts) {
 351                 frame->next = jb->frames;
 352                 frame->prev = jb->frames->prev;
 353
 354                 frame->next->prev = frame;
 355                 frame->prev->next = frame;
 356
 357                 /* frame is out of order */
 358                 jb->info.frames_ooo++;
 359
 360                 jb->frames = frame;
 361                 head = 1;
 362         } else {
 363                 p = jb->frames;
 364
 365                 /* frame is out of order */
 366                 if (resync_ts < p->prev->ts) jb->info.frames_ooo++;
 367
 368                 while (resync_ts < p->prev->ts && p->prev != jb->frames)
 369                         p = p->prev;
 370
 371                 frame->next = p;
 372                 frame->prev = p->prev;
 373
 374                 frame->next->prev = frame;
 375                 frame->prev->next = frame;
 376         }
 377         return head;
 378 }
 379
 380 static long queue_next(jitterbuf *jb)
 381 {
 382         if (jb->frames)
 383                 return jb->frames->ts;
 384         else
 385                 return -1;
 386 }
 387
 388 static long queue_last(jitterbuf *jb)
 389 {
 390         if (jb->frames)
 391                 return jb->frames->prev->ts;
 392         else
 393                 return -1;
 394 }
 395
 396 static jb_frame *_queue_get(jitterbuf *jb, long ts, int all)
 397 {
 398         jb_frame *frame;
 399         frame = jb->frames;
 400
 401         if (!frame)
 402                 return NULL;
 403
 404         /*jb_warn("queue_get: ASK %ld FIRST %ld\n", ts, frame->ts); */
 405
 406         if (all || ts >= frame->ts) {
 407                 /* remove this frame */
 408                 frame->prev->next = frame->next;
 409                 frame->next->prev = frame->prev;
 410
 411                 if (frame->next == frame)
 412                         jb->frames = NULL;
 413                 else
 414                         jb->frames = frame->next;
 415
 416
 417                 /* insert onto "free" single-linked list */
 418                 frame->next = jb->free;
 419                 jb->free = frame;
 420
 421                 jb->info.frames_cur--;
 422
 423                 /* we return the frame pointer, even though it's on free list,
 424                  * but caller must copy data */
 425                 return frame;
 426         }
 427
 428         return NULL;
 429 }
 430
 431 static jb_frame *queue_get(jitterbuf *jb, long ts)
 432 {
 433         return _queue_get(jb,ts,0);
 434 }
 435
 436 static jb_frame *queue_getall(jitterbuf *jb)
 437 {
 438         return _queue_get(jb,0,1);
 439 }
 440
 441 #if 0
 442 /* some diagnostics */
 443 static void jb_dbginfo(jitterbuf *jb)
 444 {
 445         if (dbgf == NULL)
 446                 return;
 447
 448         jb_dbg("\njb info: fin=%ld fout=%ld flate=%ld flost=%ld fdrop=%ld fcur=%ld\n",
 449                 jb->info.frames_in, jb->info.frames_out, jb->info.frames_late, jb->info.frames_lost, jb->info.frames_dropped, jb->info.frames_cur);
 450
 451         jb_dbg("jitter=%ld current=%ld target=%ld min=%ld sil=%d len=%d len/fcur=%ld\n",
 452                 jb->info.jitter, jb->info.current, jb->info.target, jb->info.min, jb->info.silence_begin_ts, jb->info.current - jb->info.min,
 453                 jb->info.frames_cur ? (jb->info.current - jb->info.min)/jb->info.frames_cur : -8);
 454         if (jb->info.frames_in > 0)
 455                 jb_dbg("jb info: Loss PCT = %ld%%, Late PCT = %ld%%\n",
 456                         jb->info.frames_lost * 100/(jb->info.frames_in + jb->info.frames_lost),
 457                         jb->info.frames_late * 100/jb->info.frames_in);
 458         jb_dbg("jb info: queue %d -> %d.  last_ts %d (queue len: %d) last_ms %d\n",
 459                 queue_next(jb),
 460                 queue_last(jb),
 461                 jb->info.next_voice_ts,
 462                 queue_last(jb) - queue_next(jb),
 463                 jb->info.last_voice_ms);
 464 }
 465 #endif
 466
 467 #ifdef DEEP_DEBUG
 468 static void jb_chkqueue(jitterbuf *jb)
 469 {
 470         int i=0;
 471         jb_frame *p = jb->frames;
 472
 473         if (!p) {
 474                 return;
 475         }
 476
 477         do {
 478                 if (p->next == NULL)  {
 479                         jb_err("Queue is BROKEN at item [%d]", i);
 480                 }
 481                 i++;
 482                 p=p->next;
 483         } while (p->next != jb->frames);
 484 }
 485
 486 static void jb_dbgqueue(jitterbuf *jb)
 487 {
 488         int i=0;
 489         jb_frame *p = jb->frames;
 490
 491         jb_dbg("queue: ");
 492
 493         if (!p) {
 494                 jb_dbg("EMPTY\n");
 495                 return;
 496         }
 497
 498         do {
 499                 jb_dbg("[%d]=%ld ", i++, p->ts);
 500                 p=p->next;
 501         } while (p->next != jb->frames);
 502
 503         jb_dbg("\n");
 504 }
 505 #endif
 506
 507 enum jb_return_code jb_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts, long now)
 508 {
 509         long numts;
 510
 511         jb_dbg2("jb_put(%x,%x,%ld,%ld,%ld)\n", jb, data, ms, ts, now);
 512
 513         jb->info.frames_in++;
 514
 515         if (jb->frames && jb->dropem)
 516                 return JB_DROP;
 517         jb->dropem = 0;
 518
 519         if (type == JB_TYPE_VOICE) {
 520                 /* presently, I'm only adding VOICE frames to history and drift calculations; mostly because with the
 521                  * IAX integrations, I'm sending retransmitted control frames with their awkward timestamps through */
 522                 if (history_put(jb,ts,now,ms))
 523                         return JB_DROP;
 524         }
 525         numts = 0;
 526         if (jb->frames)
 527                 numts = jb->frames->prev->ts - jb->frames->ts;
 528         if (numts >= jb->info.conf.max_jitterbuf) {
 529                 ast_debug(1, "Attempting to exceed Jitterbuf max %ld timeslots\n",
 530                         jb->info.conf.max_jitterbuf);
 531                 jb->dropem = 1;
 532                 return JB_DROP;
 533         }
 534         /* if put into head of queue, caller needs to reschedule */
 535         if (queue_put(jb,data,type,ms,ts)) {
 536                 return JB_SCHED;
 537         }
 538         return JB_OK;
 539 }
 540
 541
 542 static enum jb_return_code _jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
 543 {
 544         jb_frame *frame;
 545         long diff;
 546         static int dbg_cnt = 0;
 547
 548         /*if ((now - jb_next(jb)) > 2 * jb->info.last_voice_ms) jb_warn("SCHED: %ld", (now - jb_next(jb))); */
 549         /* get jitter info */
 550         history_get(jb);
 551
 552         if (dbg_cnt && dbg_cnt % 50 == 0) {
 553                 jb_dbg("\n");
 554         }
 555         dbg_cnt++;
 556
 557         /* target */
 558         jb->info.target = jb->info.jitter + jb->info.min + jb->info.conf.target_extra;
 559
 560         /* if a hard clamp was requested, use it */
 561         if ((jb->info.conf.max_jitterbuf) && ((jb->info.target - jb->info.min) > jb->info.conf.max_jitterbuf)) {
 562                 jb_dbg("clamping target from %ld to %ld\n", (jb->info.target - jb->info.min), jb->info.conf.max_jitterbuf);
 563                 jb->info.target = jb->info.min + jb->info.conf.max_jitterbuf;
 564         }
 565
 566         diff = jb->info.target - jb->info.current;
 567
 568         /* jb_warn("diff = %d lms=%d last = %d now = %d\n", diff,  */
 569         /*      jb->info.last_voice_ms, jb->info.last_adjustment, now); */
 570
 571         /* let's work on non-silent case first */
 572         if (!jb->info.silence_begin_ts) {
 573                 /* we want to grow */
 574                 if ((diff > 0) &&
 575                         /* we haven't grown in the delay length */
 576                         (((jb->info.last_adjustment + JB_ADJUST_DELAY) < now) ||
 577                         /* we need to grow more than the "length" we have left */
 578                         (diff > queue_last(jb)  - queue_next(jb)) ) ) {
 579                         /* grow by interp frame length */
 580                         jb->info.current += interpl;
 581                         jb->info.next_voice_ts += interpl;
 582                         jb->info.last_voice_ms = interpl;
 583                         jb->info.last_adjustment = now;
 584                         jb->info.cnt_contig_interp++;
 585                         if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
 586                                 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
 587                         }
 588                         jb_dbg("G");
 589                         return JB_INTERP;
 590                 }
 591
 592                 frame = queue_get(jb, jb->info.next_voice_ts - jb->info.current);
 593
 594                 /* not a voice frame; just return it. */
 595                 if (frame && frame->type != JB_TYPE_VOICE) {
 596                         if (frame->type == JB_TYPE_SILENCE) {
 597                                 jb->info.silence_begin_ts = frame->ts;
 598                                 jb->info.cnt_contig_interp = 0;
 599                         }
 600
 601                         *frameout = *frame;
 602                         jb->info.frames_out++;
 603                         jb_dbg("o");
 604                         return JB_OK;
 605                 }
 606
 607
 608                 /* voice frame is later than expected */
 609                 if (frame && frame->ts + jb->info.current < jb->info.next_voice_ts) {
 610                         if (frame->ts + jb->info.current > jb->info.next_voice_ts - jb->info.last_voice_ms) {
 611                                 /* either we interpolated past this frame in the last jb_get */
 612                                 /* or the frame is still in order, but came a little too quick */
 613                                 *frameout = *frame;
 614                                 /* reset expectation for next frame */
 615                                 jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
 616                                 jb->info.frames_out++;
 617                                 decrement_losspct(jb);
 618                                 jb->info.cnt_contig_interp = 0;
 619                                 jb_dbg("v");
 620                                 return JB_OK;
 621                         } else {
 622                                 /* voice frame is late */
 623                                 *frameout = *frame;
 624                                 jb->info.frames_out++;
 625                                 decrement_losspct(jb);
 626                                 jb->info.frames_late++;
 627                                 jb->info.frames_lost--;
 628                                 jb_dbg("l");
 629                                 /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
 630                                 jb_warninfo(jb); */
 631                                 return JB_DROP;
 632                         }
 633                 }
 634
 635                 /* keep track of frame sizes, to allow for variable sized-frames */
 636                 if (frame && frame->ms > 0) {
 637                         jb->info.last_voice_ms = frame->ms;
 638                 }
 639
 640                 /* we want to shrink; shrink at 1 frame / 500ms */
 641                 /* unless we don't have a frame, then shrink 1 frame */
 642                 /* every 80ms (though perhaps we can shrink even faster */
 643                 /* in this case) */
 644                 if (diff < -jb->info.conf.target_extra &&
 645                         ((!frame && jb->info.last_adjustment + 80 < now) ||
 646                         (jb->info.last_adjustment + 500 < now))) {
 647
 648                         jb->info.last_adjustment = now;
 649                         jb->info.cnt_contig_interp = 0;
 650
 651                         if (frame) {
 652                                 *frameout = *frame;
 653                                 /* shrink by frame size we're throwing out */
 654                                 jb->info.current -= frame->ms;
 655                                 jb->info.frames_out++;
 656                                 decrement_losspct(jb);
 657                                 jb->info.frames_dropped++;
 658                                 jb_dbg("s");
 659                                 return JB_DROP;
 660                         } else {
 661                                 /* shrink by last_voice_ms */
 662                                 jb->info.current -= jb->info.last_voice_ms;
 663                                 jb->info.frames_lost++;
 664                                 increment_losspct(jb);
 665                                 jb_dbg("S");
 666                                 return JB_NOFRAME;
 667                         }
 668                 }
 669
 670                 /* lost frame */
 671                 if (!frame) {
 672                         /* this is a bit of a hack for now, but if we're close to
 673                          * target, and we find a missing frame, it makes sense to
 674                          * grow, because the frame might just be a bit late;
 675                          * otherwise, we presently get into a pattern where we return
 676                          * INTERP for the lost frame, then it shows up next, and we
 677                          * throw it away because it's late */
 678                         /* I've recently only been able to replicate this using
 679                          * iaxclient talking to app_echo on asterisk.  In this case,
 680                          * my outgoing packets go through asterisk's (old)
 681                          * jitterbuffer, and then might get an unusual increasing delay
 682                          * there if it decides to grow?? */
 683                         /* Update: that might have been a different bug, that has been fixed..
 684                          * But, this still seemed like a good idea, except that it ended up making a single actual
 685                          * lost frame get interpolated two or more times, when there was "room" to grow, so it might
 686                          * be a bit of a bad idea overall */
 687                         /*if (diff > -1 * jb->info.last_voice_ms) {
 688                                 jb->info.current += jb->info.last_voice_ms;
 689                                 jb->info.last_adjustment = now;
 690                                 jb_warn("g");
 691                                 return JB_INTERP;
 692                         } */
 693                         jb->info.frames_lost++;
 694                         increment_losspct(jb);
 695                         jb->info.next_voice_ts += interpl;
 696                         jb->info.last_voice_ms = interpl;
 697                         jb->info.cnt_contig_interp++;
 698                         if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
 699                                 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
 700                         }
 701                         jb_dbg("L");
 702                         return JB_INTERP;
 703                 }
 704
 705                 /* normal case; return the frame, increment stuff */
 706                 *frameout = *frame;
 707                 jb->info.next_voice_ts += frame->ms;
 708                 jb->info.frames_out++;
 709                 jb->info.cnt_contig_interp = 0;
 710                 decrement_losspct(jb);
 711                 jb_dbg("v");
 712                 return JB_OK;
 713         } else {
 714                 /* TODO: after we get the non-silent case down, we'll make the
 715                  * silent case -- basically, we'll just grow and shrink faster
 716                  * here, plus handle next_voice_ts a bit differently */
 717
 718                 /* to disable silent special case altogether, just uncomment this: */
 719                 /* jb->info.silence_begin_ts = 0; */
 720
 721                 /* shrink interpl len every 10ms during silence */
 722                 if (diff < -jb->info.conf.target_extra &&
 723                         jb->info.last_adjustment + 10 <= now) {
 724                         jb->info.current -= interpl;
 725                         jb->info.last_adjustment = now;
 726                 }
 727
 728                 frame = queue_get(jb, now - jb->info.current);
 729                 if (!frame) {
 730                         return JB_NOFRAME;
 731                 } else if (frame->type != JB_TYPE_VOICE) {
 732                         /* normal case; in silent mode, got a non-voice frame */
 733                         *frameout = *frame;
 734                         jb->info.frames_out++;
 735                         return JB_OK;
 736                 }
 737                 if (frame->ts < jb->info.silence_begin_ts) {
 738                         /* voice frame is late */
 739                         *frameout = *frame;
 740                         jb->info.frames_out++;
 741                         decrement_losspct(jb);
 742                         jb->info.frames_late++;
 743                         jb->info.frames_lost--;
 744                         jb_dbg("l");
 745                         /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
 746                         jb_warninfo(jb); */
 747                         return JB_DROP;
 748                 } else {
 749                         /* voice frame */
 750                         /* try setting current to target right away here */
 751                         jb->info.current = jb->info.target;
 752                         jb->info.silence_begin_ts = 0;
 753                         jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
 754                         jb->info.last_voice_ms = frame->ms;
 755                         jb->info.frames_out++;
 756                         decrement_losspct(jb);
 757                         *frameout = *frame;
 758                         jb_dbg("V");
 759                         return JB_OK;
 760                 }
 761         }
 762 }
 763
 764 long jb_next(jitterbuf *jb)
 765 {
 766         if (jb->info.silence_begin_ts) {
 767                 if (jb->frames) {
 768                         long next = queue_next(jb);
 769                         history_get(jb);
 770                         /* shrink during silence */
 771                         if (jb->info.target - jb->info.current < -jb->info.conf.target_extra)
 772                                 return jb->info.last_adjustment + 10;
 773                         return next + jb->info.target;
 774                 }
 775                 else
 776                         return JB_LONGMAX;
 777         } else {
 778                 return jb->info.next_voice_ts;
 779         }
 780 }
 781
 782 enum jb_return_code jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
 783 {
 784         enum jb_return_code ret = _jb_get(jb, frameout, now, interpl);
 785 #if 0
 786         static int lastts=0;
 787         int thists = ((ret == JB_OK) || (ret == JB_DROP)) ? frameout->ts : 0;
 788         jb_warn("jb_get(%x,%x,%ld) = %d (%d)\n", jb, frameout, now, ret, thists);
 789         if (thists && thists < lastts) jb_warn("XXXX timestamp roll-back!!!\n");
 790         lastts = thists;
 791 #endif
 792         if (ret == JB_INTERP)
 793                 frameout->ms = jb->info.last_voice_ms;
 794
 795         return ret;
 796 }
 797
 798 enum jb_return_code jb_getall(jitterbuf *jb, jb_frame *frameout)
 799 {
 800         jb_frame *frame;
 801         frame = queue_getall(jb);
 802
 803         if (!frame) {
 804                 return JB_NOFRAME;
 805         }
 806
 807         *frameout = *frame;
 808         return JB_OK;
 809 }
 810
 811
 812 enum jb_return_code jb_getinfo(jitterbuf *jb, jb_info *stats)
 813 {
 814
 815         history_get(jb);
 816
 817         *stats = jb->info;
 818
 819         return JB_OK;
 820 }
 821
 822 enum jb_return_code jb_setconf(jitterbuf *jb, jb_conf *conf)
 823 {
 824         /* take selected settings from the struct */
 825
 826         jb->info.conf.max_jitterbuf = conf->max_jitterbuf;
 827         jb->info.conf.resync_threshold = conf->resync_threshold;
 828         jb->info.conf.max_contig_interp = conf->max_contig_interp;
 829
 830         /* -1 indicates use of the default JB_TARGET_EXTRA value */
 831         jb->info.conf.target_extra = ( conf->target_extra == -1 )
 832                 ? JB_TARGET_EXTRA
 833                 : conf->target_extra
 834                 ;
 835
 836         /* update these to match new target_extra setting */
 837         jb->info.current = jb->info.conf.target_extra;
 838         jb->info.target = jb->info.conf.target_extra;
 839
 840         return JB_OK;
 841 }
 842
 843