jitterbuf: an application-independent jitterbuffer jitterbuf.c More...

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Data Structures
struct	jb_conf

struct	jb_frame

struct	jb_info

struct	jitterbuf

Macros
configuration constants
#define	JB_ADJUST_DELAY 40

#define	JB_HISTORY_DROPPCT 3

#define	JB_HISTORY_DROPPCT_MAX 4

#define	JB_HISTORY_MAXBUF_SZ JB_HISTORY_SZ * JB_HISTORY_DROPPCT_MAX / 100

#define	JB_HISTORY_SZ 500

#define	JB_TARGET_EXTRA 40

Typedefs
typedef struct jb_conf	jb_conf

typedef struct jb_frame	jb_frame

typedef struct jb_info	jb_info

typedef void(*	jb_output_function_t) (const char *fmt,...)

typedef struct jitterbuf	jitterbuf

Enumerations
enum	jb_frame_type { JB_TYPE_CONTROL , JB_TYPE_VOICE , JB_TYPE_VIDEO , JB_TYPE_SILENCE }

enum	jb_return_code { JB_OK , JB_EMPTY , JB_NOFRAME , JB_INTERP , JB_DROP , JB_SCHED }

Functions
void	jb_destroy (jitterbuf *jb)
	destroy jitterbuf More...

enum jb_return_code	jb_get (jitterbuf jb, jb_frame frame, 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. More...

enum jb_return_code	jb_getall (jitterbuf jb, jb_frame frameout)
	unconditionally get frames from jitterbuf until empty More...

enum jb_return_code	jb_getinfo (jitterbuf jb, jb_info stats)
	get jitterbuf info: only "statistics" may be valid More...

int	jb_is_late (jitterbuf *jb, long ts)
	Checks if the given time stamp is late. More...

jitterbuf *	jb_new (void)
	new jitterbuf More...

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) More...

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 More...

void	jb_reset (jitterbuf *jb)
	reset jitterbuf More...

enum jb_return_code	jb_setconf (jitterbuf jb, jb_conf conf)
	set jitterbuf conf More...

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

Detailed Description

jitterbuf: an application-independent jitterbuffer jitterbuf.c

Definition in file jitterbuf.h.

Macro Definition Documentation

◆ JB_ADJUST_DELAY

#define JB_ADJUST_DELAY 40

ms between growing and shrinking; may not be honored if jitterbuffer runs out of space

Definition at line 45 of file jitterbuf.h.

◆ JB_HISTORY_DROPPCT

#define JB_HISTORY_DROPPCT 3

what percentage of timestamps should we drop from the history when we examine it; this might eventually be something made configurable

Definition at line 37 of file jitterbuf.h.

◆ JB_HISTORY_DROPPCT_MAX

#define JB_HISTORY_DROPPCT_MAX 4

the maximum droppct we can handle (say it was configurable).

Definition at line 39 of file jitterbuf.h.

◆ JB_HISTORY_MAXBUF_SZ

#define JB_HISTORY_MAXBUF_SZ JB_HISTORY_SZ * JB_HISTORY_DROPPCT_MAX / 100

the size of the buffer we use to keep the top and botton timestamps for dropping

Definition at line 41 of file jitterbuf.h.

◆ JB_HISTORY_SZ

#define JB_HISTORY_SZ 500

Number of historical timestamps to use in calculating jitter and drift

Definition at line 34 of file jitterbuf.h.

◆ JB_TARGET_EXTRA

#define JB_TARGET_EXTRA 40

amount of additional jitterbuffer adjustment

Definition at line 43 of file jitterbuf.h.

Typedef Documentation

◆ jb_conf

typedef struct jb_conf jb_conf

◆ jb_frame

typedef struct jb_frame jb_frame

◆ jb_info

typedef struct jb_info jb_info

◆ jb_output_function_t

typedef void(* jb_output_function_t) (const char *fmt,...)

Definition at line 168 of file jitterbuf.h.

◆ jitterbuf

typedef struct jitterbuf jitterbuf

Enumeration Type Documentation

◆ jb_frame_type

enum jb_frame_type

Enumerator
JB_TYPE_CONTROL	0
JB_TYPE_VOICE	1
JB_TYPE_VIDEO	2 - reserved
JB_TYPE_SILENCE	3

Definition at line 59 of file jitterbuf.h.

                   {
    /* frame types */
    JB_TYPE_CONTROL,  /*!< 0            */
    JB_TYPE_VOICE,    /*!< 1            */
    JB_TYPE_VIDEO,    /*!< 2 - reserved */
    JB_TYPE_SILENCE   /*!< 3            */
};

◆ jb_return_code

enum jb_return_code

Enumerator
JB_OK
JB_EMPTY
JB_NOFRAME
JB_INTERP
JB_DROP
JB_SCHED

Definition at line 49 of file jitterbuf.h.

                    {
    /* return codes */
    JB_OK,            /* 0 */
    JB_EMPTY,         /* 1 */
    JB_NOFRAME,       /* 2 */
    JB_INTERP,        /* 3 */
    JB_DROP,          /* 4 */
    JB_SCHED          /* 5 */
};

Function Documentation

◆ jb_destroy()

void jb_destroy ( jitterbuf * jb )

destroy jitterbuf

Definition at line 99 of file jitterbuf.c.

{
    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);
}

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

Referenced by AST_TEST_DEFINE(), jb_destroy_adaptive(), and pvt_destructor().

◆ jb_get()

enum jb_return_code jb_get	(	jitterbuf *	jb,
		jb_frame *	frame,
		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 785 of file jitterbuf.c.

{
    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;
}

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(), AST_TEST_DEFINE(), and jb_get_adaptive().

◆ jb_getall()

enum jb_return_code jb_getall	(	jitterbuf *	jb,
		jb_frame *	frameout
	)

unconditionally get frames from jitterbuf until empty

Definition at line 801 of file jitterbuf.c.

{
    jb_frame *frame;
    frame = queue_getall(jb);
 
    if (!frame) {
        return JB_NOFRAME;
    }
 
    *frameout = *frame;
    return JB_OK;
}

References JB_NOFRAME, JB_OK, and queue_getall().

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

◆ jb_getinfo()

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

get jitterbuf info: only "statistics" may be valid

Definition at line 815 of file jitterbuf.c.

{
 
    history_get(jb);
 
    *stats = jb->info;
 
    return JB_OK;
}

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

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

◆ jb_is_late()

int jb_is_late	(	jitterbuf *	jb,
		long	ts
	)

Checks if the given time stamp is late.

Definition at line 846 of file jitterbuf.c.

{
    return ts + jb->info.current < jb->info.next_voice_ts;
}

References jb_info::current, jitterbuf::info, and jb_info::next_voice_ts.

Referenced by jb_is_late_adaptive().

◆ jb_new()

jitterbuf * jb_new ( void )

new jitterbuf

Definition at line 86 of file jitterbuf.c.

{
    jitterbuf *jb;
 
    if (!(jb = ast_calloc(1, sizeof(*jb))))
        return NULL;
 
    jb_reset(jb);
 
    jb_dbg2("jb_new() = %x\n", jb);
    return jb;
}

References ast_calloc, jb_dbg2, jb_reset(), and NULL.

Referenced by AST_TEST_DEFINE(), jb_create_adaptive(), and new_iax().

◆ jb_next()

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 767 of file jitterbuf.c.

{
    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;
    }
}

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(), AST_TEST_DEFINE(), jb_next_adaptive(), and update_jbsched().

◆ jb_put()

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 525 of file jitterbuf.c.

{
    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;
}

References check_resync(), jb_info::frames_in, history_put(), jitterbuf::info, jb_dbg2, JB_DROP, JB_OK, JB_SCHED, JB_TYPE_VOICE, queue_put(), jb_info::resync_offset, and type.

Referenced by jb_put_adaptive(), schedule_delivery(), test_jb_late_frame_insertion(), test_jb_lost_frame_insertion(), test_jb_nominal_frame_insertion(), test_jb_out_of_order_frame_insertion(), test_jb_overflow_frame_insertion(), and test_jb_resynch_frame_insertion().

◆ jb_reset()

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 72 of file jitterbuf.c.

{
    /* 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;
}

References jb_info::conf, jb_info::current, jitterbuf::free, 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(), and jb_new().

◆ jb_setconf()

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

set jitterbuf conf

Definition at line 825 of file jitterbuf.c.

{
    /* 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;
}

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.