Jitterbuffering algorithm. More...
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Data Structures | |
| struct | fixed_jb_conf |
| struct | fixed_jb_frame |
Defines | |
| #define | FIXED_JB_RESYNCH_THRESHOLD_DEFAULT 1000 |
| #define | FIXED_JB_SIZE_DEFAULT 200 |
Enumerations | |
| enum | { FIXED_JB_OK, FIXED_JB_DROP, FIXED_JB_INTERP, FIXED_JB_NOFRAME } |
Functions | |
| void | fixed_jb_destroy (struct fixed_jb *jb) |
| int | fixed_jb_get (struct fixed_jb *jb, struct fixed_jb_frame *frame, long now, long interpl) |
| struct fixed_jb * | fixed_jb_new (struct fixed_jb_conf *conf) |
| long | fixed_jb_next (struct fixed_jb *jb) |
| int | fixed_jb_put (struct fixed_jb *jb, void *data, long ms, long ts, long now) |
| int | fixed_jb_put_first (struct fixed_jb *jb, void *data, long ms, long ts, long now) |
| int | fixed_jb_remove (struct fixed_jb *jb, struct fixed_jb_frame *frameout) |
| void | fixed_jb_set_force_resynch (struct fixed_jb *jb) |
Detailed Description
Jitterbuffering algorithm.
Definition in file fixedjitterbuf.h.
Define Documentation
| #define FIXED_JB_RESYNCH_THRESHOLD_DEFAULT 1000 |
Definition at line 45 of file fixedjitterbuf.h.
Referenced by fixed_jb_new().
| #define FIXED_JB_SIZE_DEFAULT 200 |
Definition at line 44 of file fixedjitterbuf.h.
Referenced by fixed_jb_new().
Enumeration Type Documentation
| anonymous enum |
Definition at line 35 of file fixedjitterbuf.h.
Function Documentation
| void fixed_jb_destroy | ( | struct fixed_jb * | jb | ) |
Definition at line 129 of file fixedjitterbuf.c.
References ASSERT, ast_free, and fixed_jb::frames.
Referenced by jb_destroy_fixed().
| int fixed_jb_get | ( | struct fixed_jb * | jb, |
| struct fixed_jb_frame * | frame, | ||
| long | now, | ||
| long | interpl | ||
| ) |
Definition at line 294 of file fixedjitterbuf.c.
References ASSERT, fixed_jb_frame::delivery, FIXED_JB_DROP, FIXED_JB_INTERP, FIXED_JB_NOFRAME, FIXED_JB_OK, frames, fixed_jb::frames, get_jb_head(), fixed_jb_frame::ms, and fixed_jb::next_delivery.
Referenced by jb_get_fixed().
{
ASSERT(now >= 0);
ASSERT(interpl >= 2);
if (now < jb->next_delivery) {
/* too early for the next frame */
return FIXED_JB_NOFRAME;
}
/* Is the jb empty? */
if (!jb->frames) {
/* should interpolate a frame */
/* update next */
jb->next_delivery += interpl;
return FIXED_JB_INTERP;
}
/* Isn't it too late for the first frame available in the jb? */
if (now > jb->frames->delivery + jb->frames->ms) {
/* yes - should drop this frame and update next to point the next frame (get_jb_head() does it) */
get_jb_head(jb, frame);
return FIXED_JB_DROP;
}
/* isn't it too early to play the first frame available? */
if (now < jb->frames->delivery) {
/* yes - should interpolate one frame */
/* update next */
jb->next_delivery += interpl;
return FIXED_JB_INTERP;
}
/* we have a frame for playing now (get_jb_head() updates next) */
get_jb_head(jb, frame);
return FIXED_JB_OK;
}
| struct fixed_jb* fixed_jb_new | ( | struct fixed_jb_conf * | conf | ) | [read] |
Definition at line 102 of file fixedjitterbuf.c.
References ast_calloc, fixed_jb::conf, fixed_jb::delay, FIXED_JB_RESYNCH_THRESHOLD_DEFAULT, FIXED_JB_SIZE_DEFAULT, fixed_jb_conf::jbsize, and fixed_jb_conf::resync_threshold.
Referenced by jb_create_fixed().
{
struct fixed_jb *jb;
if (!(jb = ast_calloc(1, sizeof(*jb))))
return NULL;
/* First copy our config */
memcpy(&jb->conf, conf, sizeof(struct fixed_jb_conf));
/* we don't need the passed config anymore - continue working with the saved one */
conf = &jb->conf;
/* validate the configuration */
if (conf->jbsize < 1)
conf->jbsize = FIXED_JB_SIZE_DEFAULT;
if (conf->resync_threshold < 1)
conf->resync_threshold = FIXED_JB_RESYNCH_THRESHOLD_DEFAULT;
/* Set the constant delay to the jitterbuf */
jb->delay = conf->jbsize;
return jb;
}
| long fixed_jb_next | ( | struct fixed_jb * | jb | ) |
Definition at line 337 of file fixedjitterbuf.c.
References fixed_jb::next_delivery.
Referenced by jb_next_fixed().
{
return jb->next_delivery;
}
| int fixed_jb_put | ( | struct fixed_jb * | jb, |
| void * | data, | ||
| long | ms, | ||
| long | ts, | ||
| long | now | ||
| ) |
Definition at line 200 of file fixedjitterbuf.c.
References alloc_jb_frame(), ASSERT, fixed_jb::conf, fixed_jb_frame::data, fixed_jb::delay, fixed_jb_frame::delivery, FIXED_JB_OK, fixed_jb::force_resynch, fixed_jb::frames, fixed_jb_frame::ms, fixed_jb_frame::next, fixed_jb::next_delivery, fixed_jb_frame::prev, fixed_jb_conf::resync_threshold, resynch_jb(), fixed_jb::rxcore, fixed_jb::tail, and fixed_jb_frame::ts.
Referenced by fixed_jb_put_first(), jb_put_fixed(), and resynch_jb().
{
struct fixed_jb_frame *frame, *next, *newframe;
long delivery;
/* debug check the validity of the input params */
ASSERT(data != NULL);
/* do not allow frames shorter than 2 ms */
ASSERT(ms >= 2);
ASSERT(ts >= 0);
ASSERT(now >= 0);
delivery = jb->rxcore + jb->delay + ts;
/* check if the new frame is not too late */
if (delivery < jb->next_delivery) {
/* should drop the frame, but let first resynch_jb() check if this is not a jump in ts, or
the force resynch flag was not set. */
return resynch_jb(jb, data, ms, ts, now);
}
/* what if the delivery time is bigger than next + delay? Seems like a frame for the future.
However, allow more resync_threshold ms in advance */
if (delivery > jb->next_delivery + jb->delay + jb->conf.resync_threshold) {
/* should drop the frame, but let first resynch_jb() check if this is not a jump in ts, or
the force resynch flag was not set. */
return resynch_jb(jb, data, ms, ts, now);
}
/* find the right place in the frames list, sorted by delivery time */
frame = jb->tail;
while (frame && frame->delivery > delivery) {
frame = frame->prev;
}
/* Check if the new delivery time is not covered already by the chosen frame */
if (frame && (frame->delivery == delivery ||
delivery < frame->delivery + frame->ms ||
(frame->next && delivery + ms > frame->next->delivery)))
{
/* TODO: Should we check for resynch here? Be careful to do not allow threshold smaller than
the size of the jb */
/* should drop the frame, but let first resynch_jb() check if this is not a jump in ts, or
the force resynch flag was not set. */
return resynch_jb(jb, data, ms, ts, now);
}
/* Reset the force resynch flag */
jb->force_resynch = 0;
/* Get a new frame */
newframe = alloc_jb_frame(jb);
newframe->data = data;
newframe->ts = ts;
newframe->ms = ms;
newframe->delivery = delivery;
/* and insert it right on place */
if (frame) {
next = frame->next;
frame->next = newframe;
if (next) {
newframe->next = next;
next->prev = newframe;
} else {
/* insert after the last frame - should update tail */
jb->tail = newframe;
newframe->next = NULL;
}
newframe->prev = frame;
return FIXED_JB_OK;
} else if (!jb->frames) {
/* the frame list is empty or thats just the first frame ever */
/* tail should also be NULL is that case */
ASSERT(jb->tail == NULL);
jb->frames = jb->tail = newframe;
newframe->next = NULL;
newframe->prev = NULL;
return FIXED_JB_OK;
} else {
/* insert on a first position - should update frames head */
newframe->next = jb->frames;
newframe->prev = NULL;
jb->frames->prev = newframe;
jb->frames = newframe;
return FIXED_JB_OK;
}
}
| int fixed_jb_put_first | ( | struct fixed_jb * | jb, |
| void * | data, | ||
| long | ms, | ||
| long | ts, | ||
| long | now | ||
| ) |
Definition at line 187 of file fixedjitterbuf.c.
References fixed_jb::delay, fixed_jb_put(), fixed_jb::next_delivery, fixed_jb::rxcore, and fixed_jb_frame::ts.
Referenced by jb_put_first_fixed(), and resynch_jb().
{
/* this is our first frame - set the base of the receivers time */
jb->rxcore = now - ts;
/* init next for a first time - it should be the time the first frame should be played */
jb->next_delivery = now + jb->delay;
/* put the frame */
return fixed_jb_put(jb, data, ms, ts, now);
}
| int fixed_jb_remove | ( | struct fixed_jb * | jb, |
| struct fixed_jb_frame * | frameout | ||
| ) |
Definition at line 343 of file fixedjitterbuf.c.
References FIXED_JB_NOFRAME, FIXED_JB_OK, fixed_jb::frames, and get_jb_head().
Referenced by jb_empty_and_reset_fixed(), and jb_remove_fixed().
{
if (!jb->frames)
return FIXED_JB_NOFRAME;
get_jb_head(jb, frameout);
return FIXED_JB_OK;
}
| void fixed_jb_set_force_resynch | ( | struct fixed_jb * | jb | ) |
Definition at line 181 of file fixedjitterbuf.c.
References fixed_jb::force_resynch.
Referenced by jb_force_resynch_fixed().
{
jb->force_resynch = 1;
}
