jitterbuf: an application-independent jitterbuffer More...

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

Include dependency graph for jitterbuf.c:

Defines
#define	jb_dbg(...) (dbgf ? dbgf(__VA_ARGS__) : (void)0)
#define	jb_dbg2(...) ((void)0)
#define	jb_err(...) (errf ? errf(__VA_ARGS__) : (void)0)
#define	JB_LONGMAX 2147483647L
#define	JB_LONGMIN (-JB_LONGMAX - 1L)
#define	jb_warn(...) (warnf ? warnf(__VA_ARGS__) : (void)0)
Functions
static enum jb_return_code	_jb_get (jitterbuf jb, jb_frame frameout, long now, long interpl)
static jb_frame *	_queue_get (jitterbuf *jb, long ts, int all)
static void	decrement_losspct (jitterbuf *jb)
static void	history_calc_maxbuf (jitterbuf *jb)
static void	history_get (jitterbuf *jb)
static int	history_put (jitterbuf *jb, long ts, long now, long ms)
	simple history manipulation
static void	increment_losspct (jitterbuf *jb)
void	jb_destroy (jitterbuf *jb)
	destroy jitterbuf
enum jb_return_code	jb_get (jitterbuf jb, jb_frame frameout, long now, long interpl)
	get a frame for time now (receiver's time) return value is one of JB_OK: You've got frame! JB_DROP: Here's an audio frame you should just drop. Ask me again for this time.. JB_NOFRAME: There's no frame scheduled for this time. JB_INTERP: Please interpolate an interpl-length frame for this time (either we need to grow, or there was a lost frame) JB_EMPTY: The jb is empty.
enum jb_return_code	jb_getall (jitterbuf jb, jb_frame frameout)
	unconditionally get frames from jitterbuf until empty
enum jb_return_code	jb_getinfo (jitterbuf jb, jb_info stats)
	get jitterbuf info: only "statistics" may be valid
jitterbuf *	jb_new ()
	new jitterbuf
long	jb_next (jitterbuf *jb)
	when is the next frame due out, in receiver's time (0=EMPTY) This value may change as frames are added (esp non-audio frames)
enum jb_return_code	jb_put (jitterbuf jb, void data, const enum jb_frame_type type, long ms, long ts, long now)
	queue a frame
void	jb_reset (jitterbuf *jb)
	reset jitterbuf
enum jb_return_code	jb_setconf (jitterbuf jb, jb_conf conf)
	set jitterbuf conf
void	jb_setoutput (jb_output_function_t err, jb_output_function_t warn, jb_output_function_t dbg)
static jb_frame *	queue_get (jitterbuf *jb, long ts)
static jb_frame *	queue_getall (jitterbuf *jb)
static long	queue_last (jitterbuf *jb)
static long	queue_next (jitterbuf *jb)
static int	queue_put (jitterbuf jb, void data, const enum jb_frame_type type, long ms, long ts)
Variables
static jb_output_function_t	dbgf
static jb_output_function_t	errf
static jb_output_function_t	warnf

Detailed Description

jitterbuf: an application-independent jitterbuffer

Author:: Steve Kann <stevek@stevek.com>

Definition in file jitterbuf.c.

Define Documentation

#define jb_dbg ( ... ) (dbgf ? dbgf(__VA_ARGS__) : (void)0)

Definition at line 43 of file jitterbuf.c.

Referenced by _jb_get().

#define jb_dbg2 ( ... ) ((void)0)

Definition at line 48 of file jitterbuf.c.

Referenced by jb_destroy(), jb_new(), and jb_put().

#define jb_err ( ... ) (errf ? errf(__VA_ARGS__) : (void)0)

Definition at line 42 of file jitterbuf.c.

Referenced by queue_put().

#define JB_LONGMAX 2147483647L

define these here, just for ancient compiler systems

Definition at line 38 of file jitterbuf.c.

Referenced by history_calc_maxbuf(), and jb_next().

#define JB_LONGMIN (-JB_LONGMAX - 1L)

Definition at line 39 of file jitterbuf.c.

Referenced by history_calc_maxbuf().

#define jb_warn ( ... ) (warnf ? warnf(__VA_ARGS__) : (void)0)

Definition at line 41 of file jitterbuf.c.

Referenced by history_put(), and jb_get().

Function Documentation

static enum jb_return_code _jb_get	(	jitterbuf *	jb,
		jb_frame *	frameout,
		long	now,
		long	interpl
	)		`[static]`

Definition at line 548 of file jitterbuf.c.

References jb_info::cnt_contig_interp, jb_info::conf, jb_info::current, decrement_losspct(), jb_info::frames_dropped, jb_info::frames_late, jb_info::frames_lost, jb_info::frames_out, history_get(), increment_losspct(), jitterbuf::info, JB_ADJUST_DELAY, jb_dbg, JB_DROP, JB_INTERP, JB_NOFRAME, JB_OK, JB_TYPE_SILENCE, JB_TYPE_VOICE, jb_info::jitter, jb_info::last_adjustment, jb_info::last_voice_ms, jb_conf::max_contig_interp, jb_conf::max_jitterbuf, jb_info::min, jb_frame::ms, jb_info::next_voice_ts, queue_get(), queue_last(), queue_next(), jb_info::silence_begin_ts, jb_info::target, jb_conf::target_extra, jb_frame::ts, and jb_frame::type.

Referenced by jb_get().

{
   jb_frame *frame;
   long diff;
   static int dbg_cnt = 0;

   /*if ((now - jb_next(jb)) > 2 * jb->info.last_voice_ms) jb_warn("SCHED: %ld", (now - jb_next(jb))); */
   /* 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");
            /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
            jb_warninfo(jb); */
            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");
         /*jb_warn("\nlate: wanted=%ld, this=%ld, next=%ld\n", jb->info.next_voice_ts - jb->info.current, frame->ts, queue_next(jb));
         jb_warninfo(jb); */
         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;
      }
   }
}

static jb_frame* _queue_get	(	jitterbuf *	jb,
		long	ts,
		int	all
	)		`[static]`

Definition at line 396 of file jitterbuf.c.

References jitterbuf::frames, jb_info::frames_cur, jitterbuf::free, jitterbuf::info, jb_frame::next, jb_frame::prev, and jb_frame::ts.

Referenced by queue_get(), and queue_getall().

{
   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 void decrement_losspct ( jitterbuf * jb ) [static]

Definition at line 65 of file jitterbuf.c.

References jitterbuf::info, and jb_info::losspct.

Referenced by _jb_get().

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

static void history_calc_maxbuf ( jitterbuf * jb ) [static]

Definition at line 200 of file jitterbuf.c.

References jitterbuf::hist_maxbuf, jitterbuf::hist_maxbuf_valid, jitterbuf::hist_minbuf, jitterbuf::hist_ptr, jitterbuf::history, JB_HISTORY_MAXBUF_SZ, JB_HISTORY_SZ, JB_LONGMAX, and JB_LONGMIN.

Referenced by history_get().

{
   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 */
               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 */
               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 ) [static]

Definition at line 277 of file jitterbuf.c.

References jitterbuf::hist_maxbuf, jitterbuf::hist_maxbuf_valid, jitterbuf::hist_minbuf, jitterbuf::hist_ptr, history_calc_maxbuf(), jitterbuf::info, JB_HISTORY_DROPPCT, JB_HISTORY_MAXBUF_SZ, JB_HISTORY_SZ, jb_info::jitter, and jb_info::min.

Referenced by _jb_get(), jb_getinfo(), and jb_next().

{
   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;
}

static int history_put	(	jitterbuf *	jb,
		long	ts,
		long	now,
		long	ms
	)		`[static]`

simple history manipulation

Note:: maybe later we can make the history buckets variable size, or something?

Definition at line 125 of file jitterbuf.c.

References jb_info::cnt_delay_discont, jb_info::conf, jitterbuf::hist_maxbuf, jitterbuf::hist_maxbuf_valid, jitterbuf::hist_ptr, jitterbuf::history, jitterbuf::info, JB_HISTORY_MAXBUF_SZ, JB_HISTORY_SZ, jb_warn, jb_info::jitter, jb_info::last_delay, jb_info::resync_offset, and jb_conf::resync_threshold.

Referenced by jb_put().

{
   long delay = now - (ts - jb->info.resync_offset);
   long threshold = 2 * jb->info.jitter + jb->info.conf.resync_threshold;
   long kicked;

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

   /* check for drastic change in delay */
   if (jb->info.conf.resync_threshold != -1) {
      if (abs(delay - jb->info.last_delay) > threshold) {
         jb->info.cnt_delay_discont++;
         if (jb->info.cnt_delay_discont > 3) {
            /* resync the jitterbuffer */
            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 {
            return -1;
         }
      } else {
         jb->info.last_delay = delay;
         jb->info.cnt_delay_discont = 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 increment_losspct ( jitterbuf * jb ) [static]

Definition at line 60 of file jitterbuf.c.

References jitterbuf::info, and jb_info::losspct.

Referenced by _jb_get().

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

void jb_destroy ( jitterbuf * jb )

destroy jitterbuf

Definition at line 95 of file jitterbuf.c.

References ast_free, jitterbuf::free, jb_dbg2, and jb_frame::next.

Referenced by jb_destroy_adaptive(), and pvt_destructor().

{
   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);
}

enum jb_return_code jb_get	(	jitterbuf *	jb,
		jb_frame *	frameout,
		long	now,
		long	interpl
	)

get a frame for time now (receiver's time) return value is one of JB_OK: You've got frame! JB_DROP: Here's an audio frame you should just drop. Ask me again for this time.. JB_NOFRAME: There's no frame scheduled for this time. JB_INTERP: Please interpolate an interpl-length frame for this time (either we need to grow, or there was a lost frame) JB_EMPTY: The jb is empty.

Definition at line 788 of file jitterbuf.c.

References _jb_get(), jitterbuf::info, JB_DROP, JB_INTERP, JB_OK, jb_warn, jb_info::last_voice_ms, jb_frame::ms, and jb_frame::ts.

Referenced by __get_from_jb(), and jb_get_adaptive().

{
   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
	)

unconditionally get frames from jitterbuf until empty

Definition at line 804 of file jitterbuf.c.

References JB_NOFRAME, JB_OK, and queue_getall().

Referenced by complete_transfer(), jb_empty_and_reset_adaptive(), jb_remove_adaptive(), pvt_destructor(), and schedule_delivery().

{
   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
	)

get jitterbuf info: only "statistics" may be valid

Definition at line 818 of file jitterbuf.c.

References history_get(), jitterbuf::info, and JB_OK.

Referenced by ast_cli_netstats(), construct_rr(), handle_cli_iax2_show_channels(), and log_jitterstats().

{

   history_get(jb);

   *stats = jb->info;

   return JB_OK;
}

jitterbuf* jb_new ( void )

new jitterbuf

Definition at line 82 of file jitterbuf.c.

References ast_malloc, jb_dbg2, and jb_reset().

Referenced by jb_create_adaptive(), and new_iax().

{
   jitterbuf *jb;

   if (!(jb = ast_malloc(sizeof(*jb)))) 
      return NULL;

   jb_reset(jb);

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

long jb_next ( jitterbuf * jb )

when is the next frame due out, in receiver's time (0=EMPTY) This value may change as frames are added (esp non-audio frames)

Definition at line 770 of file jitterbuf.c.

References jb_info::conf, jb_info::current, jitterbuf::frames, history_get(), jitterbuf::info, JB_LONGMAX, jb_info::last_adjustment, jb_info::next_voice_ts, queue_next(), jb_info::silence_begin_ts, jb_info::target, and jb_conf::target_extra.

Referenced by __get_from_jb(), jb_next_adaptive(), and update_jbsched().

{
   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_put	(	jitterbuf *	jb,
		void *	data,
		const enum jb_frame_type	type,
		long	ms,
		long	ts,
		long	now
	)

queue a frame

data=frame data, timings (in ms): ms=length of frame (for voice), ts=ts (sender's time) now=now (in receiver's time) return value is one of JB_OK: Frame added. Last call to jb_next() still valid JB_DROP: Drop this frame immediately JB_SCHED: Frame added. Call jb_next() to get a new time for the next frame

Definition at line 507 of file jitterbuf.c.

References ast_debug, jb_info::conf, jitterbuf::dropem, jitterbuf::frames, jb_info::frames_dropped, jb_info::frames_in, history_put(), jitterbuf::info, jb_dbg2, JB_DROP, JB_OK, JB_SCHED, JB_TYPE_VOICE, jb_conf::max_jitterbuf, jb_frame::prev, queue_put(), and jb_frame::ts.

Referenced by jb_put_adaptive(), and schedule_delivery().

{
   long numts;

   jb_dbg2("jb_put(%x,%x,%ld,%ld,%ld)\n", jb, data, ms, ts, now);

   numts = 0;
   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 JB_DROP;
   } else {
      jb->dropem = 0;
   }

   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 */
      if (history_put(jb,ts,now,ms)) {
         jb->info.frames_dropped++;
         return JB_DROP;
      }
   }

   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;
}

void jb_reset ( jitterbuf * jb )

reset jitterbuf

Note:: The jitterbuffer should be empty before you call this, otherwise you will leak queued frames, and some internal structures

Definition at line 70 of file jitterbuf.c.

References jb_info::conf, jb_info::current, jitterbuf::info, JB_TARGET_EXTRA, jb_info::silence_begin_ts, jb_info::target, and jb_conf::target_extra.

Referenced by complete_transfer(), jb_empty_and_reset_adaptive(), jb_new(), and schedule_delivery().

{
   /* only save settings */
   jb_conf s = jb->info.conf;
   memset(jb, 0, sizeof(*jb));
   jb->info.conf = s;

   /* 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; 
}

enum jb_return_code jb_setconf	(	jitterbuf *	jb,
		jb_conf *	conf
	)

set jitterbuf conf

Definition at line 828 of file jitterbuf.c.

References jb_info::conf, jb_info::current, jitterbuf::info, JB_OK, JB_TARGET_EXTRA, jb_conf::max_contig_interp, jb_conf::max_jitterbuf, jb_conf::resync_threshold, jb_info::target, and jb_conf::target_extra.

Referenced by jb_create_adaptive(), and new_iax().

{
   /* 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;
}

void jb_setoutput	(	jb_output_function_t	err,
		jb_output_function_t	warn,
		jb_output_function_t	dbg
	)

Definition at line 53 of file jitterbuf.c.

Referenced by handle_cli_iax2_set_debug_jb(), and load_module().

{
   errf = err;
   warnf = warn;
   dbgf = dbg;
}

static jb_frame* queue_get	(	jitterbuf *	jb,
		long	ts
	)		`[static]`

Definition at line 431 of file jitterbuf.c.

References _queue_get().

Referenced by _jb_get().

{
   return _queue_get(jb,ts,0);
}

static jb_frame* queue_getall ( jitterbuf * jb ) [static]

Definition at line 436 of file jitterbuf.c.

References _queue_get().

Referenced by jb_getall().

{
   return _queue_get(jb,0,1);
}

static long queue_last ( jitterbuf * jb ) [static]

Definition at line 388 of file jitterbuf.c.

References jitterbuf::frames, jb_frame::prev, and jb_frame::ts.

Referenced by _jb_get().

{
   if (jb->frames) 
      return jb->frames->prev->ts;
   else 
      return -1;
}

static long queue_next ( jitterbuf * jb ) [static]

Definition at line 380 of file jitterbuf.c.

References jitterbuf::frames, and jb_frame::ts.

Referenced by _jb_get(), and jb_next().

{
   if (jb->frames) 
      return jb->frames->ts;
   else 
      return -1;
}

static int queue_put	(	jitterbuf *	jb,
		void *	data,
		const enum jb_frame_type	type,
		long	ms,
		long	ts
	)		`[static]`

Definition at line 319 of file jitterbuf.c.

References ast_malloc, jb_frame::data, frames, jitterbuf::frames, jb_info::frames_cur, jb_info::frames_ooo, jitterbuf::free, jitterbuf::info, jb_err, jb_frame::ms, jb_frame::next, jb_frame::prev, jb_info::resync_offset, jb_frame::ts, type, and jb_frame::type.

Referenced by jb_put().

{
   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 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;
}

Variable Documentation

jb_output_function_t dbgf

Definition at line 51 of file jitterbuf.c.

jb_output_function_t errf

Definition at line 51 of file jitterbuf.c.

jb_output_function_t warnf [static]

Definition at line 51 of file jitterbuf.c.

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