2 * jitterbuf: an application-independent jitterbuffer
5 * Copyright (C) 2004-2005, Horizon Wimba, Inc.
8 * Steve Kann <stevek@stevek.com>
10 * This program is free software, distributed under the terms of
11 * the GNU Lesser (Library) General Public License
13 * Copyright on this file is disclaimed to Digium for inclusion in Asterisk
19 #include <sys/types.h>
21 #include "jitterbuf.h"
23 /* define these here, just for ancient compiler systems */
24 #define JB_LONGMAX 2147483647L
25 #define JB_LONGMIN (-JB_LONGMAX - 1L)
27 /* MS VC can't do __VA_ARGS__ */
28 #if (defined(WIN32) || defined(_WIN32_WCE)) && defined(_MSC_VER)
29 #define jb_warn if (warnf) warnf
30 #define jb_err if (errf) errf
31 #define jb_dbg if (dbgf) dbgf
34 #define jb_dbg2 if (dbgf) dbgf
36 #define jb_dbg2 if (0) dbgf
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)
46 #define jb_dbg2(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)
48 #define jb_dbg2(...) ((void)0)
53 static jb_output_function_t warnf, errf, dbgf;
55 void jb_setoutput(jb_output_function_t err, jb_output_function_t warn, jb_output_function_t dbg)
62 static void increment_losspct(jitterbuf *jb)
64 jb->info.losspct = (100000 + 499 * jb->info.losspct)/500;
67 static void decrement_losspct(jitterbuf *jb)
69 jb->info.losspct = (499 * jb->info.losspct)/500;
72 void jb_reset(jitterbuf *jb)
74 /* only save settings */
75 jb_conf s = jb->info.conf;
76 memset(jb, 0, sizeof(*jb));
79 /* initialize length, using the configured value */
80 jb->info.current = jb->info.target = jb->info.conf.target_extra;
81 jb->info.silence_begin_ts = -1;
88 if (!(jb = (jitterbuf *)malloc(sizeof(*jb))))
91 jb->info.conf.target_extra = JB_TARGET_EXTRA;
95 jb_dbg2("jb_new() = %x\n", jb);
99 void jb_destroy(jitterbuf *jb)
102 jb_dbg2("jb_destroy(%x)\n", jb);
104 /* free all the frames on the "free list" */
106 while (frame != NULL) {
107 jb_frame *next = frame->next;
112 /* free ourselves! */
119 static int longcmp(const void *a, const void *b)
121 return *(long *)a - *(long *)b;
125 /* simple history manipulation */
126 /* maybe later we can make the history buckets variable size, or something? */
127 /* drop parameter determines whether we will drop outliers to minimize
129 static int history_put(jitterbuf *jb, long ts, long now, long ms)
131 long delay = now - (ts - jb->info.resync_offset);
132 long threshold = 2 * jb->info.jitter + jb->info.conf.resync_threshold;
135 /* don't add special/negative times to history */
139 /* check for drastic change in delay */
140 if (jb->info.conf.resync_threshold != -1) {
141 if (abs(delay - jb->info.last_delay) > threshold) {
142 jb->info.cnt_delay_discont++;
143 if (jb->info.cnt_delay_discont > 3) {
144 /* resync the jitterbuffer */
145 jb->info.cnt_delay_discont = 0;
147 jb->hist_maxbuf_valid = 0;
149 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);
150 jb->info.resync_offset = ts - now;
151 jb->info.last_delay = delay = 0; /* after resync, frame is right on time */
156 jb->info.last_delay = delay;
157 jb->info.cnt_delay_discont = 0;
161 kicked = jb->history[jb->hist_ptr % JB_HISTORY_SZ];
163 jb->history[(jb->hist_ptr++) % JB_HISTORY_SZ] = delay;
165 /* optimization; the max/min buffers don't need to be recalculated,
166 * if this packet's entry doesn't change them. This happens if this
167 * packet is not involved, _and_ any packet that got kicked out of
168 * the history is also not involved. We do a number of comparisons,
169 * but it's probably still worthwhile, because it will usually
170 * succeed, and should be a lot faster than going through all 500
171 * packets in history */
172 if (!jb->hist_maxbuf_valid)
175 /* don't do this until we've filled history
176 * (reduces some edge cases below) */
177 if (jb->hist_ptr < JB_HISTORY_SZ)
180 /* if the new delay would go into min */
181 if (delay < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
185 if (delay > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
188 /* or the kicked delay would be in min */
189 if (kicked <= jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
192 if (kicked >= jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
195 /* if we got here, we don't need to invalidate, 'cause this delay didn't
198 /* end optimization */
202 jb->hist_maxbuf_valid = 0;
206 static void history_calc_maxbuf(jitterbuf *jb)
210 if (jb->hist_ptr == 0)
214 /* initialize maxbuf/minbuf to the latest value */
215 for (i=0;i<JB_HISTORY_MAXBUF_SZ;i++) {
217 * jb->hist_maxbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
218 * jb->hist_minbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
220 jb->hist_maxbuf[i] = JB_LONGMIN;
221 jb->hist_minbuf[i] = JB_LONGMAX;
224 /* use insertion sort to populate maxbuf */
225 /* we want it to be the top "n" values, in order */
227 /* start at the beginning, or JB_HISTORY_SZ frames ago */
228 i = (jb->hist_ptr > JB_HISTORY_SZ) ? (jb->hist_ptr - JB_HISTORY_SZ) : 0;
230 for (;i<jb->hist_ptr;i++) {
231 long toins = jb->history[i % JB_HISTORY_SZ];
233 /* if the maxbuf should get this */
234 if (toins > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1]) {
236 /* insertion-sort it into the maxbuf */
237 for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
238 /* found where it fits */
239 if (toins > jb->hist_maxbuf[j]) {
241 memmove(jb->hist_maxbuf + j + 1, jb->hist_maxbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_maxbuf[0]));
243 jb->hist_maxbuf[j] = toins;
250 /* if the minbuf should get this */
251 if (toins < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1]) {
253 /* insertion-sort it into the maxbuf */
254 for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
255 /* found where it fits */
256 if (toins < jb->hist_minbuf[j]) {
258 memmove(jb->hist_minbuf + j + 1, jb->hist_minbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_minbuf[0]));
260 jb->hist_minbuf[j] = toins;
269 fprintf(stderr, "toins = %ld\n", toins);
270 fprintf(stderr, "maxbuf =");
271 for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
272 fprintf(stderr, "%ld ", jb->hist_maxbuf[k]);
273 fprintf(stderr, "\nminbuf =");
274 for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
275 fprintf(stderr, "%ld ", jb->hist_minbuf[k]);
276 fprintf(stderr, "\n");
280 jb->hist_maxbuf_valid = 1;
283 static void history_get(jitterbuf *jb)
285 long max, min, jitter;
289 if (!jb->hist_maxbuf_valid)
290 history_calc_maxbuf(jb);
292 /* count is how many items in history we're examining */
293 count = (jb->hist_ptr < JB_HISTORY_SZ) ? jb->hist_ptr : JB_HISTORY_SZ;
295 /* index is the "n"ths highest/lowest that we'll look for */
296 index = count * JB_HISTORY_DROPPCT / 100;
298 /* sanity checks for index */
299 if (index > (JB_HISTORY_MAXBUF_SZ - 1))
300 index = JB_HISTORY_MAXBUF_SZ - 1;
309 max = jb->hist_maxbuf[index];
310 min = jb->hist_minbuf[index];
314 /* these debug stmts compare the difference between looking at the absolute jitter, and the
315 * values we get by throwing away the outliers */
317 fprintf(stderr, "[%d] min=%d, max=%d, jitter=%d\n", index, min, max, jitter);
318 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]);
322 jb->info.jitter = jitter;
325 /* returns 1 if frame was inserted into head of queue, 0 otherwise */
326 static int queue_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts)
331 long resync_ts = ts - jb->info.resync_offset;
333 if ((frame = jb->free)) {
334 jb->free = frame->next;
335 } else if (!(frame = (jb_frame *)malloc(sizeof(*frame)))) {
336 jb_err("cannot allocate frame\n");
340 jb->info.frames_cur++;
343 frame->ts = resync_ts;
348 * frames are a circular list, jb-frames points to to the lowest ts,
349 * jb->frames->prev points to the highest ts
352 if (!jb->frames) { /* queue is empty */
357 } else if (resync_ts < jb->frames->ts) {
358 frame->next = jb->frames;
359 frame->prev = jb->frames->prev;
361 frame->next->prev = frame;
362 frame->prev->next = frame;
364 /* frame is out of order */
365 jb->info.frames_ooo++;
372 /* frame is out of order */
373 if (resync_ts < p->prev->ts) jb->info.frames_ooo++;
375 while (resync_ts < p->prev->ts && p->prev != jb->frames)
379 frame->prev = p->prev;
381 frame->next->prev = frame;
382 frame->prev->next = frame;
387 static long queue_next(jitterbuf *jb)
390 return jb->frames->ts;
395 static long queue_last(jitterbuf *jb)
398 return jb->frames->prev->ts;
403 static jb_frame *_queue_get(jitterbuf *jb, long ts, int all)
411 /*jb_warn("queue_get: ASK %ld FIRST %ld\n", ts, frame->ts); */
413 if (all || ts >= frame->ts) {
414 /* remove this frame */
415 frame->prev->next = frame->next;
416 frame->next->prev = frame->prev;
418 if (frame->next == frame)
421 jb->frames = frame->next;
424 /* insert onto "free" single-linked list */
425 frame->next = jb->free;
428 jb->info.frames_cur--;
430 /* we return the frame pointer, even though it's on free list,
431 * but caller must copy data */
438 static jb_frame *queue_get(jitterbuf *jb, long ts)
440 return _queue_get(jb,ts,0);
443 static jb_frame *queue_getall(jitterbuf *jb)
445 return _queue_get(jb,0,1);
449 /* some diagnostics */
450 static void jb_dbginfo(jitterbuf *jb)
455 jb_dbg("\njb info: fin=%ld fout=%ld flate=%ld flost=%ld fdrop=%ld fcur=%ld\n",
456 jb->info.frames_in, jb->info.frames_out, jb->info.frames_late, jb->info.frames_lost, jb->info.frames_dropped, jb->info.frames_cur);
458 jb_dbg("jitter=%ld current=%ld target=%ld min=%ld sil=%d len=%d len/fcur=%ld\n",
459 jb->info.jitter, jb->info.current, jb->info.target, jb->info.min, jb->info.silence_begin_ts, jb->info.current - jb->info.min,
460 jb->info.frames_cur ? (jb->info.current - jb->info.min)/jb->info.frames_cur : -8);
461 if (jb->info.frames_in > 0)
462 jb_dbg("jb info: Loss PCT = %ld%%, Late PCT = %ld%%\n",
463 jb->info.frames_lost * 100/(jb->info.frames_in + jb->info.frames_lost),
464 jb->info.frames_late * 100/jb->info.frames_in);
465 jb_dbg("jb info: queue %d -> %d. last_ts %d (queue len: %d) last_ms %d\n",
468 jb->info.next_voice_ts,
469 queue_last(jb) - queue_next(jb),
470 jb->info.last_voice_ms);
475 static void jb_chkqueue(jitterbuf *jb)
478 jb_frame *p = jb->frames;
485 if (p->next == NULL) {
486 jb_err("Queue is BROKEN at item [%d]", i);
490 } while (p->next != jb->frames);
493 static void jb_dbgqueue(jitterbuf *jb)
496 jb_frame *p = jb->frames;
506 jb_dbg("[%d]=%ld ", i++, p->ts);
508 } while (p->next != jb->frames);
514 enum jb_return_code jb_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts, long now)
516 jb_dbg2("jb_put(%x,%x,%ld,%ld,%ld)\n", jb, data, ms, ts, now);
518 jb->info.frames_in++;
520 if (type == JB_TYPE_VOICE) {
521 /* presently, I'm only adding VOICE frames to history and drift
522 * calculations; mostly because with the IAX integrations, I'm
523 * sending retransmitted control frames with their awkward
526 if (history_put(jb,ts,now,ms))
530 /* if put into head of queue, caller needs to reschedule */
531 if (queue_put(jb,data,type,ms,ts)) {
539 static enum jb_return_code _jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
544 /*if ((now - jb_next(jb)) > 2 * jb->info.last_voice_ms) jb_warn("SCHED: %ld", (now - jb_next(jb))); */
545 /* get jitter info */
550 jb->info.target = jb->info.jitter + jb->info.min + jb->info.conf.target_extra;
552 /* if a hard clamp was requested, use it */
553 if ((jb->info.conf.max_jitterbuf) && ((jb->info.target - jb->info.min) > jb->info.conf.max_jitterbuf)) {
554 jb_dbg("clamping target from %d to %d\n", (jb->info.target - jb->info.min), jb->info.conf.max_jitterbuf);
555 jb->info.target = jb->info.min + jb->info.conf.max_jitterbuf;
558 diff = jb->info.target - jb->info.current;
560 /* jb_warn("diff = %d lms=%d last = %d now = %d\n", diff, */
561 /* jb->info.last_voice_ms, jb->info.last_adjustment, now); */
563 /* let's work on non-silent case first */
564 if (!jb->info.silence_begin_ts) {
565 /* we want to grow */
567 /* we haven't grown in the delay length */
568 (((jb->info.last_adjustment + JB_ADJUST_DELAY) < now) ||
569 /* we need to grow more than the "length" we have left */
570 (diff > queue_last(jb) - queue_next(jb)) ) ) {
571 /* grow by interp frame length */
572 jb->info.current += interpl;
573 jb->info.next_voice_ts += interpl;
574 jb->info.last_voice_ms = interpl;
575 jb->info.last_adjustment = now;
576 jb->info.cnt_contig_interp++;
577 /* assume silence instead of continuing to interpolate */
578 if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
579 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
585 frame = queue_get(jb, jb->info.next_voice_ts - jb->info.current);
587 /* not a voice frame; just return it. */
588 if (frame && frame->type != JB_TYPE_VOICE) {
589 /* track start of silence */
590 if (frame->type == JB_TYPE_SILENCE) {
591 jb->info.silence_begin_ts = frame->ts;
592 jb->info.cnt_contig_interp = 0;
596 jb->info.frames_out++;
601 /* voice frame is later than expected */
602 if (frame && frame->ts + jb->info.current < jb->info.next_voice_ts) {
603 if (frame->ts + jb->info.current > jb->info.next_voice_ts - jb->info.last_voice_ms) {
604 /* either we interpolated past this frame in the last jb_get */
605 /* or the frame is still in order, but came a little too quick */
607 /* reset expectation for next frame */
608 jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
609 jb->info.frames_out++;
610 decrement_losspct(jb);
611 jb->info.cnt_contig_interp = 0;
615 /* voice frame is late */
617 jb->info.frames_out++;
618 decrement_losspct(jb);
619 jb->info.frames_late++;
620 jb->info.frames_lost--;
622 /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
628 /* keep track of frame sizes, to allow for variable sized-frames */
629 if (frame && frame->ms > 0) {
630 jb->info.last_voice_ms = frame->ms;
633 /* we want to shrink; shrink at 1 frame / 500ms */
634 /* unless we don't have a frame, then shrink 1 frame */
635 /* every 80ms (though perhaps we can shrink even faster */
637 if (diff < -jb->info.conf.target_extra &&
638 ((!frame && jb->info.last_adjustment + 80 < now) ||
639 (jb->info.last_adjustment + 500 < now))) {
641 jb->info.last_adjustment = now;
642 jb->info.cnt_contig_interp = 0;
646 /* shrink by frame size we're throwing out */
647 jb->info.current -= frame->ms;
648 jb->info.frames_out++;
649 decrement_losspct(jb);
650 jb->info.frames_dropped++;
654 /* shrink by last_voice_ms */
655 jb->info.current -= jb->info.last_voice_ms;
656 jb->info.frames_lost++;
657 increment_losspct(jb);
665 /* this is a bit of a hack for now, but if we're close to
666 * target, and we find a missing frame, it makes sense to
667 * grow, because the frame might just be a bit late;
668 * otherwise, we presently get into a pattern where we return
669 * INTERP for the lost frame, then it shows up next, and we
670 * throw it away because it's late */
671 /* I've recently only been able to replicate this using
672 * iaxclient talking to app_echo on asterisk. In this case,
673 * my outgoing packets go through asterisk's (old)
674 * jitterbuffer, and then might get an unusual increasing delay
675 * there if it decides to grow?? */
676 /* Update: that might have been a different bug, that has been fixed..
677 * But, this still seemed like a good idea, except that it ended up making a single actual
678 * lost frame get interpolated two or more times, when there was "room" to grow, so it might
679 * be a bit of a bad idea overall */
680 /*if (diff > -1 * jb->info.last_voice_ms) {
681 jb->info.current += jb->info.last_voice_ms;
682 jb->info.last_adjustment = now;
686 jb->info.frames_lost++;
687 increment_losspct(jb);
688 jb->info.next_voice_ts += interpl;
689 jb->info.last_voice_ms = interpl;
690 jb->info.cnt_contig_interp++;
691 /* assume silence instead of continuing to interpolate */
692 if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
693 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
699 /* normal case; return the frame, increment stuff */
701 jb->info.next_voice_ts += frame->ms;
702 jb->info.frames_out++;
703 jb->info.cnt_contig_interp = 0;
704 decrement_losspct(jb);
708 /* TODO: after we get the non-silent case down, we'll make the
709 * silent case -- basically, we'll just grow and shrink faster
710 * here, plus handle next_voice_ts a bit differently */
712 /* to disable silent special case altogether, just uncomment this: */
713 /* jb->info.silence_begin_ts = 0; */
715 /* shrink interpl len every 10ms during silence */
716 if (diff < -jb->info.conf.target_extra &&
717 jb->info.last_adjustment + 10 <= now) {
718 jb->info.current -= interpl;
719 jb->info.last_adjustment = now;
722 frame = queue_get(jb, now - jb->info.current);
725 } else if (frame->type != JB_TYPE_VOICE) {
726 /* normal case; in silent mode, got a non-voice frame */
728 jb->info.frames_out++;
731 if (frame->ts < jb->info.silence_begin_ts) {
732 /* voice frame is late */
734 jb->info.frames_out++;
735 decrement_losspct(jb);
736 jb->info.frames_late++;
737 jb->info.frames_lost--;
739 /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
744 /* try setting current to target right away here */
745 jb->info.current = jb->info.target;
746 jb->info.silence_begin_ts = 0;
747 jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
748 jb->info.last_voice_ms = frame->ms;
749 jb->info.frames_out++;
750 decrement_losspct(jb);
758 long jb_next(jitterbuf *jb)
760 if (jb->info.silence_begin_ts) {
762 long next = queue_next(jb);
764 /* shrink during silence */
765 if (jb->info.target - jb->info.current < -jb->info.conf.target_extra)
766 return jb->info.last_adjustment + 10;
767 return next + jb->info.target;
772 return jb->info.next_voice_ts;
776 enum jb_return_code jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
778 enum jb_return_code ret = _jb_get(jb, frameout, now, interpl);
781 int thists = ((ret == JB_OK) || (ret == JB_DROP)) ? frameout->ts : 0;
782 jb_warn("jb_get(%x,%x,%ld) = %d (%d)\n", jb, frameout, now, ret, thists);
783 if (thists && thists < lastts) jb_warn("XXXX timestamp roll-back!!!\n");
789 enum jb_return_code jb_getall(jitterbuf *jb, jb_frame *frameout)
792 frame = queue_getall(jb);
803 enum jb_return_code jb_getinfo(jitterbuf *jb, jb_info *stats)
812 enum jb_return_code jb_setconf(jitterbuf *jb, jb_conf *conf)
814 /* take selected settings from the struct */
816 jb->info.conf.max_jitterbuf = conf->max_jitterbuf;
817 jb->info.conf.resync_threshold = conf->resync_threshold;
818 jb->info.conf.max_contig_interp = conf->max_contig_interp;
820 /* -1 indicates use of the default JB_TARGET_EXTRA value */
821 jb->info.conf.target_extra = ( conf->target_extra == -1 )
826 /* update these to match new target_extra setting */
827 jb->info.current = jb->info.conf.target_extra;
828 jb->info.target = jb->info.conf.target_extra;