jitterbuf.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2004-2005, Horizon Wimba, Inc.
 *
 * Contributors:
 * Steve Kann <[email protected]>
 *
 * A license has been granted to Digium (via disclaimer) for the use of
 * this code.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief jitterbuf: an application-independent jitterbuffer
 * \author Steve Kann <[email protected]>
 *
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "jitterbuf.h"
#include "asterisk/utils.h"

/*! define these here, just for ancient compiler systems */
#define JB_LONGMAX 2147483647L
#define JB_LONGMIN (-JB_LONGMAX - 1L)

#define jb_warn(...) (warnf ? warnf(__VA_ARGS__) : (void)0)
#define jb_err(...) (errf ? errf(__VA_ARGS__) : (void)0)
#define jb_dbg(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)

#ifdef DEEP_DEBUG
#define jb_dbg2(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)
#else
#define jb_dbg2(...) ((void)0)
#endif

static jb_output_function_t warnf, errf, dbgf;

void jb_setoutput(jb_output_function_t err, jb_output_function_t warn, jb_output_function_t dbg)
{
 errf = err;
 warnf = warn;
 dbgf = dbg;
}

static void increment_losspct(jitterbuf *jb)
{
 jb->info.losspct = (100000 + 499 * jb->info.losspct)/500;
}

static void decrement_losspct(jitterbuf *jb)
{
 jb->info.losspct = (499 * jb->info.losspct)/500;
}

void jb_reset(jitterbuf *jb)
{
 /* only save settings and free list */
 jb_conf s = jb->info.conf;
 jb_frame *fr = jb->free;
 memset(jb, 0, sizeof(*jb));
 jb->info.conf = s;
 jb->free = fr;

 /* initialize length, using the default value */
 jb->info.current = jb->info.target = jb->info.conf.target_extra = JB_TARGET_EXTRA;
 jb->info.silence_begin_ts = -1;
}

jitterbuf * jb_new()
{
 jitterbuf *jb;

 if (!(jb = ast_calloc(1, sizeof(*jb))))
 return NULL;

 jb_reset(jb);

 jb_dbg2("jb_new() = %x\n", jb);
 return jb;
}

void jb_destroy(jitterbuf *jb)
{
 jb_frame *frame;
 jb_dbg2("jb_destroy(%x)\n", jb);

 /* free all the frames on the "free list" */
 frame = jb->free;
 while (frame != NULL) {
 jb_frame *next = frame->next;
 ast_free(frame);
 frame = next;
 }

 /* free ourselves! */
 ast_free(jb);
}

static int check_resync(jitterbuf *jb, long ts, long now, long ms, const enum jb_frame_type type, long *delay)
{
 long numts = 0;
 long threshold = 2 * jb->info.jitter + jb->info.conf.resync_threshold;

 /* Check for overfill of the buffer */
 if (jb->frames) {
 numts = jb->frames->prev->ts - jb->frames->ts;
 }

 if (numts >= (jb->info.conf.max_jitterbuf)) {
 if (!jb->dropem) {
 ast_debug(1, "Attempting to exceed Jitterbuf max %ld timeslots\n",
 jb->info.conf.max_jitterbuf);
 jb->dropem = 1;
 }
 jb->info.frames_dropped++;
 return -1;
 } else {
 jb->dropem = 0;
 }

 /* check for drastic change in delay */
 if (jb->info.conf.resync_threshold != -1) {
 if (labs(*delay - jb->info.last_delay) > threshold) {
 jb->info.cnt_delay_discont++;
 /* resync the jitterbuffer on 3 consecutive discontinuities,
 * or immediately if a control frame */
 if ((jb->info.cnt_delay_discont > 3) || (type == JB_TYPE_CONTROL)) {
 jb->info.cnt_delay_discont = 0;
 jb->hist_ptr = 0;
 jb->hist_maxbuf_valid = 0;
 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);
 jb->info.resync_offset = ts - now;
 jb->info.last_delay = *delay = 0; /* after resync, frame is right on time */
 } else {
 jb->info.frames_dropped++;
 return -1;
 }
 } else {
 jb->info.last_delay = *delay;
 jb->info.cnt_delay_discont = 0;
 }
 }
 return 0;
}

static int history_put(jitterbuf *jb, long ts, long now, long ms, long delay)
{
 long kicked;

 /* don't add special/negative times to history */
 if (ts <= 0)
 return 0;

 kicked = jb->history[jb->hist_ptr % JB_HISTORY_SZ];

 jb->history[(jb->hist_ptr++) % JB_HISTORY_SZ] = delay;

 /* optimization; the max/min buffers don't need to be recalculated, if this packet's
 * entry doesn't change them. This happens if this packet is not involved, _and_ any packet
 * that got kicked out of the history is also not involved
 * We do a number of comparisons, but it's probably still worthwhile, because it will usually
 * succeed, and should be a lot faster than going through all 500 packets in history */
 if (!jb->hist_maxbuf_valid)
 return 0;

 /* don't do this until we've filled history
 * (reduces some edge cases below) */
 if (jb->hist_ptr < JB_HISTORY_SZ)
 goto invalidate;

 /* if the new delay would go into min */
 if (delay < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
 goto invalidate;

 /* or max.. */
 if (delay > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
 goto invalidate;

 /* or the kicked delay would be in min */
 if (kicked <= jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1])
 goto invalidate;

 if (kicked >= jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1])
 goto invalidate;

 /* if we got here, we don't need to invalidate, 'cause this delay didn't
 * affect things */
 return 0;
 /* end optimization */


invalidate:
 jb->hist_maxbuf_valid = 0;
 return 0;
}

static void history_calc_maxbuf(jitterbuf *jb)
{
 int i,j;

 if (jb->hist_ptr == 0)
 return;


 /* initialize maxbuf/minbuf to the latest value */
 for (i=0;i<JB_HISTORY_MAXBUF_SZ;i++) {
/*
 * jb->hist_maxbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
 * jb->hist_minbuf[i] = jb->history[(jb->hist_ptr-1) % JB_HISTORY_SZ];
 */
 jb->hist_maxbuf[i] = JB_LONGMIN;
 jb->hist_minbuf[i] = JB_LONGMAX;
 }

 /* use insertion sort to populate maxbuf */
 /* we want it to be the top "n" values, in order */

 /* start at the beginning, or JB_HISTORY_SZ frames ago */
 i = (jb->hist_ptr > JB_HISTORY_SZ) ? (jb->hist_ptr - JB_HISTORY_SZ) : 0;

 for (;i<jb->hist_ptr;i++) {
 long toins = jb->history[i % JB_HISTORY_SZ];

 /* if the maxbuf should get this */
 if (toins > jb->hist_maxbuf[JB_HISTORY_MAXBUF_SZ-1]) {

 /* insertion-sort it into the maxbuf */
 for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
 /* found where it fits */
 if (toins > jb->hist_maxbuf[j]) {
 /* move over */
 if (j != JB_HISTORY_MAXBUF_SZ - 1) {
 memmove(jb->hist_maxbuf + j + 1, jb->hist_maxbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_maxbuf[0]));
 }
 /* insert */
 jb->hist_maxbuf[j] = toins;

 break;
 }
 }
 }

 /* if the minbuf should get this */
 if (toins < jb->hist_minbuf[JB_HISTORY_MAXBUF_SZ-1]) {

 /* insertion-sort it into the maxbuf */
 for (j=0;j<JB_HISTORY_MAXBUF_SZ;j++) {
 /* found where it fits */
 if (toins < jb->hist_minbuf[j]) {
 /* move over */
 if (j != JB_HISTORY_MAXBUF_SZ - 1) {
 memmove(jb->hist_minbuf + j + 1, jb->hist_minbuf + j, (JB_HISTORY_MAXBUF_SZ - (j + 1)) * sizeof(jb->hist_minbuf[0]));
 }
 /* insert */
 jb->hist_minbuf[j] = toins;

 break;
 }
 }
 }

 if (0) {
 int k;
 fprintf(stderr, "toins = %ld\n", toins);
 fprintf(stderr, "maxbuf =");
 for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
 fprintf(stderr, "%ld ", jb->hist_maxbuf[k]);
 fprintf(stderr, "\nminbuf =");
 for (k=0;k<JB_HISTORY_MAXBUF_SZ;k++)
 fprintf(stderr, "%ld ", jb->hist_minbuf[k]);
 fprintf(stderr, "\n");
 }
 }

 jb->hist_maxbuf_valid = 1;
}

static void history_get(jitterbuf *jb)
{
 long max, min, jitter;
 int idx;
 int count;

 if (!jb->hist_maxbuf_valid)
 history_calc_maxbuf(jb);

 /* count is how many items in history we're examining */
 count = (jb->hist_ptr < JB_HISTORY_SZ) ? jb->hist_ptr : JB_HISTORY_SZ;

 /* idx is the "n"ths highest/lowest that we'll look for */
 idx = count * JB_HISTORY_DROPPCT / 100;

 /* sanity checks for idx */
 if (idx > (JB_HISTORY_MAXBUF_SZ - 1))
 idx = JB_HISTORY_MAXBUF_SZ - 1;

 if (idx < 0) {
 jb->info.min = 0;
 jb->info.jitter = 0;
 return;
 }

 max = jb->hist_maxbuf[idx];
 min = jb->hist_minbuf[idx];

 jitter = max - min;

 /* these debug stmts compare the difference between looking at the absolute jitter, and the
 * values we get by throwing away the outliers */
 /*
 fprintf(stderr, "[%d] min=%d, max=%d, jitter=%d\n", index, min, max, jitter);
 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]);
 */

 jb->info.min = min;
 jb->info.jitter = jitter;
}

/* returns 1 if frame was inserted into head of queue, 0 otherwise */
static int queue_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts)
{
 jb_frame *frame;
 jb_frame *p;
 int head = 0;
 long resync_ts = ts - jb->info.resync_offset;

 if ((frame = jb->free)) {
 jb->free = frame->next;
 } else if (!(frame = ast_malloc(sizeof(*frame)))) {
 jb_err("cannot allocate frame\n");
 return 0;
 }

 jb->info.frames_cur++;

 frame->data = data;
 frame->ts = resync_ts;
 frame->ms = ms;
 frame->type = type;

 /*
 * frames are a circular list, jb-frames points to the lowest ts,
 * jb->frames->prev points to the highest ts
 */

 if (!jb->frames) { /* queue is empty */
 jb->frames = frame;
 frame->next = frame;
 frame->prev = frame;
 head = 1;
 } else if (resync_ts < jb->frames->ts) {
 frame->next = jb->frames;
 frame->prev = jb->frames->prev;

 frame->next->prev = frame;
 frame->prev->next = frame;

 /* frame is out of order */
 jb->info.frames_ooo++;

 jb->frames = frame;
 head = 1;
 } else {
 p = jb->frames;

 /* frame is out of order */
 if (resync_ts < p->prev->ts) jb->info.frames_ooo++;

 while (resync_ts < p->prev->ts && p->prev != jb->frames)
 p = p->prev;

 frame->next = p;
 frame->prev = p->prev;

 frame->next->prev = frame;
 frame->prev->next = frame;
 }
 return head;
}

static long queue_next(jitterbuf *jb)
{
 if (jb->frames)
 return jb->frames->ts;
 else
 return -1;
}

static long queue_last(jitterbuf *jb)
{
 if (jb->frames)
 return jb->frames->prev->ts;
 else
 return -1;
}

static jb_frame *_queue_get(jitterbuf *jb, long ts, int all)
{
 jb_frame *frame;
 frame = jb->frames;

 if (!frame)
 return NULL;

 /*jb_warn("queue_get: ASK %ld FIRST %ld\n", ts, frame->ts); */

 if (all || ts >= frame->ts) {
 /* remove this frame */
 frame->prev->next = frame->next;
 frame->next->prev = frame->prev;

 if (frame->next == frame)
 jb->frames = NULL;
 else
 jb->frames = frame->next;


 /* insert onto "free" single-linked list */
 frame->next = jb->free;
 jb->free = frame;

 jb->info.frames_cur--;

 /* we return the frame pointer, even though it's on free list,
 * but caller must copy data */
 return frame;
 }

 return NULL;
}

static jb_frame *queue_get(jitterbuf *jb, long ts)
{
 return _queue_get(jb,ts,0);
}

static jb_frame *queue_getall(jitterbuf *jb)
{
 return _queue_get(jb,0,1);
}

#if 0
/* some diagnostics */
static void jb_dbginfo(jitterbuf *jb)
{
 if (dbgf == NULL)
 return;

 jb_dbg("\njb info: fin=%ld fout=%ld flate=%ld flost=%ld fdrop=%ld fcur=%ld\n",
 jb->info.frames_in, jb->info.frames_out, jb->info.frames_late, jb->info.frames_lost, jb->info.frames_dropped, jb->info.frames_cur);

 jb_dbg("jitter=%ld current=%ld target=%ld min=%ld sil=%d len=%d len/fcur=%ld\n",
 jb->info.jitter, jb->info.current, jb->info.target, jb->info.min, jb->info.silence_begin_ts, jb->info.current - jb->info.min,
 jb->info.frames_cur ? (jb->info.current - jb->info.min)/jb->info.frames_cur : -8);
 if (jb->info.frames_in > 0)
 jb_dbg("jb info: Loss PCT = %ld%%, Late PCT = %ld%%\n",
 jb->info.frames_lost * 100/(jb->info.frames_in + jb->info.frames_lost),
 jb->info.frames_late * 100/jb->info.frames_in);
 jb_dbg("jb info: queue %d -> %d. last_ts %d (queue len: %d) last_ms %d\n",
 queue_next(jb),
 queue_last(jb),
 jb->info.next_voice_ts,
 queue_last(jb) - queue_next(jb),
 jb->info.last_voice_ms);
}
#endif

#ifdef DEEP_DEBUG
static void jb_chkqueue(jitterbuf *jb)
{
 int i=0;
 jb_frame *p = jb->frames;

 if (!p) {
 return;
 }

 do {
 if (p->next == NULL) {
 jb_err("Queue is BROKEN at item [%d]", i);
 }
 i++;
 p=p->next;
 } while (p->next != jb->frames);
}

static void jb_dbgqueue(jitterbuf *jb)
{
 int i=0;
 jb_frame *p = jb->frames;

 jb_dbg("queue: ");

 if (!p) {
 jb_dbg("EMPTY\n");
 return;
 }

 do {
 jb_dbg("[%d]=%ld ", i++, p->ts);
 p=p->next;
 } while (p->next != jb->frames);

 jb_dbg("\n");
}
#endif

enum jb_return_code jb_put(jitterbuf *jb, void *data, const enum jb_frame_type type, long ms, long ts, long now)
{
 long delay = now - (ts - jb->info.resync_offset);
 jb_dbg2("jb_put(%x,%x,%ld,%ld,%ld)\n", jb, data, ms, ts, now);

 if (check_resync(jb, ts, now, ms, type, &delay)) {
 return JB_DROP;
 }

 if (type == JB_TYPE_VOICE) {
 /* presently, I'm only adding VOICE frames to history and drift calculations; mostly because with the
 * IAX integrations, I'm sending retransmitted control frames with their awkward timestamps through */
 history_put(jb, ts, now, ms, delay);
 }

 jb->info.frames_in++;

 /* if put into head of queue, caller needs to reschedule */
 if (queue_put(jb,data,type,ms,ts)) {
 return JB_SCHED;
 }
 return JB_OK;
}


static enum jb_return_code _jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
{
 jb_frame *frame;
 long diff;
 static int dbg_cnt = 0;

 /* get jitter info */
 history_get(jb);

 if (dbg_cnt && dbg_cnt % 50 == 0) {
 jb_dbg("\n");
 }
 dbg_cnt++;

 /* target */
 jb->info.target = jb->info.jitter + jb->info.min + jb->info.conf.target_extra;

 /* if a hard clamp was requested, use it */
 if ((jb->info.conf.max_jitterbuf) && ((jb->info.target - jb->info.min) > jb->info.conf.max_jitterbuf)) {
 jb_dbg("clamping target from %ld to %ld\n", (jb->info.target - jb->info.min), jb->info.conf.max_jitterbuf);
 jb->info.target = jb->info.min + jb->info.conf.max_jitterbuf;
 }

 diff = jb->info.target - jb->info.current;

 /* jb_warn("diff = %d lms=%d last = %d now = %d\n", diff, */
 /* jb->info.last_voice_ms, jb->info.last_adjustment, now); */

 /* let's work on non-silent case first */
 if (!jb->info.silence_begin_ts) {
 /* we want to grow */
 if ((diff > 0) &&
 /* we haven't grown in the delay length */
 (((jb->info.last_adjustment + JB_ADJUST_DELAY) < now) ||
 /* we need to grow more than the "length" we have left */
 (diff > queue_last(jb) - queue_next(jb)) ) ) {
 /* grow by interp frame length */
 jb->info.current += interpl;
 jb->info.next_voice_ts += interpl;
 jb->info.last_voice_ms = interpl;
 jb->info.last_adjustment = now;
 jb->info.cnt_contig_interp++;
 if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
 }
 jb_dbg("G");
 return JB_INTERP;
 }

 frame = queue_get(jb, jb->info.next_voice_ts - jb->info.current);

 /* not a voice frame; just return it. */
 if (frame && frame->type != JB_TYPE_VOICE) {
 if (frame->type == JB_TYPE_SILENCE) {
 jb->info.silence_begin_ts = frame->ts;
 jb->info.cnt_contig_interp = 0;
 }

 *frameout = *frame;
 jb->info.frames_out++;
 jb_dbg("o");
 return JB_OK;
 }


 /* voice frame is later than expected */
 if (frame && frame->ts + jb->info.current < jb->info.next_voice_ts) {
 if (frame->ts + jb->info.current > jb->info.next_voice_ts - jb->info.last_voice_ms) {
 /* either we interpolated past this frame in the last jb_get */
 /* or the frame is still in order, but came a little too quick */
 *frameout = *frame;
 /* reset expectation for next frame */
 jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
 jb->info.frames_out++;
 decrement_losspct(jb);
 jb->info.cnt_contig_interp = 0;
 jb_dbg("v");
 return JB_OK;
 } else {
 /* voice frame is late */
 *frameout = *frame;
 jb->info.frames_out++;
 decrement_losspct(jb);
 jb->info.frames_late++;
 jb->info.frames_lost--;
 jb_dbg("l");
 return JB_DROP;
 }
 }

 /* keep track of frame sizes, to allow for variable sized-frames */
 if (frame && frame->ms > 0) {
 jb->info.last_voice_ms = frame->ms;
 }

 /* we want to shrink; shrink at 1 frame / 500ms */
 /* unless we don't have a frame, then shrink 1 frame */
 /* every 80ms (though perhaps we can shrink even faster */
 /* in this case) */
 if (diff < -jb->info.conf.target_extra &&
 ((!frame && jb->info.last_adjustment + 80 < now) ||
 (jb->info.last_adjustment + 500 < now))) {

 jb->info.last_adjustment = now;
 jb->info.cnt_contig_interp = 0;

 if (frame) {
 *frameout = *frame;
 /* shrink by frame size we're throwing out */
 jb->info.current -= frame->ms;
 jb->info.frames_out++;
 decrement_losspct(jb);
 jb->info.frames_dropped++;
 jb_dbg("s");
 return JB_DROP;
 } else {
 /* shrink by last_voice_ms */
 jb->info.current -= jb->info.last_voice_ms;
 jb->info.frames_lost++;
 increment_losspct(jb);
 jb_dbg("S");
 return JB_NOFRAME;
 }
 }

 /* lost frame */
 if (!frame) {
 /* this is a bit of a hack for now, but if we're close to
 * target, and we find a missing frame, it makes sense to
 * grow, because the frame might just be a bit late;
 * otherwise, we presently get into a pattern where we return
 * INTERP for the lost frame, then it shows up next, and we
 * throw it away because it's late */
 /* I've recently only been able to replicate this using
 * iaxclient talking to app_echo on asterisk. In this case,
 * my outgoing packets go through asterisk's (old)
 * jitterbuffer, and then might get an unusual increasing delay
 * there if it decides to grow?? */
 /* Update: that might have been a different bug, that has been fixed..
 * But, this still seemed like a good idea, except that it ended up making a single actual
 * lost frame get interpolated two or more times, when there was "room" to grow, so it might
 * be a bit of a bad idea overall */
 /*if (diff > -1 * jb->info.last_voice_ms) {
 jb->info.current += jb->info.last_voice_ms;
 jb->info.last_adjustment = now;
 jb_warn("g");
 return JB_INTERP;
 } */
 jb->info.frames_lost++;
 increment_losspct(jb);
 jb->info.next_voice_ts += interpl;
 jb->info.last_voice_ms = interpl;
 jb->info.cnt_contig_interp++;
 if (jb->info.conf.max_contig_interp && jb->info.cnt_contig_interp >= jb->info.conf.max_contig_interp) {
 jb->info.silence_begin_ts = jb->info.next_voice_ts - jb->info.current;
 }
 jb_dbg("L");
 return JB_INTERP;
 }

 /* normal case; return the frame, increment stuff */
 *frameout = *frame;
 jb->info.next_voice_ts += frame->ms;
 jb->info.frames_out++;
 jb->info.cnt_contig_interp = 0;
 decrement_losspct(jb);
 jb_dbg("v");
 return JB_OK;
 } else {
 /* TODO: after we get the non-silent case down, we'll make the
 * silent case -- basically, we'll just grow and shrink faster
 * here, plus handle next_voice_ts a bit differently */

 /* to disable silent special case altogether, just uncomment this: */
 /* jb->info.silence_begin_ts = 0; */

 /* shrink interpl len every 10ms during silence */
 if (diff < -jb->info.conf.target_extra &&
 jb->info.last_adjustment + 10 <= now) {
 jb->info.current -= interpl;
 jb->info.last_adjustment = now;
 }

 frame = queue_get(jb, now - jb->info.current);
 if (!frame) {
 return JB_NOFRAME;
 } else if (frame->type != JB_TYPE_VOICE) {
 /* normal case; in silent mode, got a non-voice frame */
 *frameout = *frame;
 jb->info.frames_out++;
 return JB_OK;
 }
 if (frame->ts < jb->info.silence_begin_ts) {
 /* voice frame is late */
 *frameout = *frame;
 jb->info.frames_out++;
 decrement_losspct(jb);
 jb->info.frames_late++;
 jb->info.frames_lost--;
 jb_dbg("l");
 return JB_DROP;
 } else {
 /* voice frame */
 /* try setting current to target right away here */
 jb->info.current = jb->info.target;
 jb->info.silence_begin_ts = 0;
 jb->info.next_voice_ts = frame->ts + jb->info.current + frame->ms;
 jb->info.last_voice_ms = frame->ms;
 jb->info.frames_out++;
 decrement_losspct(jb);
 *frameout = *frame;
 jb_dbg("V");
 return JB_OK;
 }
 }
}

long jb_next(jitterbuf *jb)
{
 if (jb->info.silence_begin_ts) {
 if (jb->frames) {
 long next = queue_next(jb);
 history_get(jb);
 /* shrink during silence */
 if (jb->info.target - jb->info.current < -jb->info.conf.target_extra)
 return jb->info.last_adjustment + 10;
 return next + jb->info.target;
 }
 else
 return JB_LONGMAX;
 } else {
 return jb->info.next_voice_ts;
 }
}

enum jb_return_code jb_get(jitterbuf *jb, jb_frame *frameout, long now, long interpl)
{
 enum jb_return_code ret = _jb_get(jb, frameout, now, interpl);
#if 0
 static int lastts=0;
 int thists = ((ret == JB_OK) || (ret == JB_DROP)) ? frameout->ts : 0;
 jb_warn("jb_get(%x,%x,%ld) = %d (%d)\n", jb, frameout, now, ret, thists);
 if (thists && thists < lastts) jb_warn("XXXX timestamp roll-back!!!\n");
 lastts = thists;
#endif
 if (ret == JB_INTERP)
 frameout->ms = jb->info.last_voice_ms;

 return ret;
}

enum jb_return_code jb_getall(jitterbuf *jb, jb_frame *frameout)
{
 jb_frame *frame;
 frame = queue_getall(jb);

 if (!frame) {
 return JB_NOFRAME;
 }

 *frameout = *frame;
 return JB_OK;
}


enum jb_return_code jb_getinfo(jitterbuf *jb, jb_info *stats)
{

 history_get(jb);

 *stats = jb->info;

 return JB_OK;
}

enum jb_return_code jb_setconf(jitterbuf *jb, jb_conf *conf)
{
 /* take selected settings from the struct */

 jb->info.conf.max_jitterbuf = conf->max_jitterbuf;
 jb->info.conf.resync_threshold = conf->resync_threshold;
 jb->info.conf.max_contig_interp = conf->max_contig_interp;

 /* -1 indicates use of the default JB_TARGET_EXTRA value */
 jb->info.conf.target_extra = ( conf->target_extra == -1 )
 ? JB_TARGET_EXTRA
 : conf->target_extra
 ;

 /* update these to match new target_extra setting */
 jb->info.current = jb->info.conf.target_extra;
 jb->info.target = jb->info.conf.target_extra;

 return JB_OK;
}

int jb_is_late(jitterbuf *jb, long ts)
{
 return ts + jb->info.current < jb->info.next_voice_ts;
}