abstract_jb.h File Reference

Common implementation-independent jitterbuffer stuff. More...

#include <sys/time.h>

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Data Structures
struct	ast_jb
	General jitterbuffer state. More...
struct	ast_jb_conf
	General jitterbuffer configuration. More...
Defines
#define	AST_JB_CONF_ENABLE   "enable"
#define	AST_JB_CONF_FORCE   "force"
#define	AST_JB_CONF_IMPL   "impl"
#define	AST_JB_CONF_LOG   "log"
#define	AST_JB_CONF_MAX_SIZE   "maxsize"
#define	AST_JB_CONF_PREFIX   "jb"
#define	AST_JB_CONF_RESYNCH_THRESHOLD   "resyncthreshold"
#define	AST_JB_CONF_TARGET_EXTRA   "targetextra"
#define	AST_JB_IMPL_NAME_SIZE   12
Enumerations
enum	{ AST_JB_ENABLED = (1 << 0), AST_JB_FORCED = (1 << 1), AST_JB_LOG = (1 << 2) }
Functions
void	ast_jb_configure (struct ast_channel *chan, const struct ast_jb_conf *conf)
	Configures a jitterbuffer on a channel.
void	ast_jb_destroy (struct ast_channel *chan)
	Destroys jitterbuffer on a channel.
int	ast_jb_do_usecheck (struct ast_channel *c0, struct ast_channel *c1)
	Checks the need of a jb use in a generic bridge.
void	ast_jb_empty_and_reset (struct ast_channel *c0, struct ast_channel *c1)
	drops all frames from a jitterbuffer and resets it
void	ast_jb_get_and_deliver (struct ast_channel *c0, struct ast_channel *c1)
	Deliver the queued frames that should be delivered now for both channels.
void	ast_jb_get_config (const struct ast_channel *chan, struct ast_jb_conf *conf)
	Copies a channel's jitterbuffer configuration.
int	ast_jb_get_when_to_wakeup (struct ast_channel *c0, struct ast_channel *c1, int time_left)
	Calculates the time, left to the closest delivery moment in a bridge.
int	ast_jb_put (struct ast_channel *chan, struct ast_frame *f)
	Puts a frame into a channel jitterbuffer.
int	ast_jb_read_conf (struct ast_jb_conf *conf, const char *varname, const char *value)
	Sets jitterbuffer configuration property.

---

Detailed Description

Common implementation-independent jitterbuffer stuff.

Author:

Slav Klenov <slav@securax.org>

Definition in file abstract_jb.h.

---

Define Documentation

#define AST_JB_CONF_ENABLE   "enable"

Definition at line 70 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_FORCE   "force"

Definition at line 71 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_IMPL   "impl"

Definition at line 75 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_LOG   "log"

Definition at line 76 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_MAX_SIZE   "maxsize"

Definition at line 72 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_PREFIX   "jb"

Definition at line 69 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_RESYNCH_THRESHOLD   "resyncthreshold"

Definition at line 73 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_CONF_TARGET_EXTRA   "targetextra"

Definition at line 74 of file abstract_jb.h.

Referenced by ast_jb_read_conf().

#define AST_JB_IMPL_NAME_SIZE   12

Definition at line 48 of file abstract_jb.h.

Referenced by create_jb().

---

Enumeration Type Documentation

anonymous enum

Enumerator:

AST_JB_ENABLED
AST_JB_FORCED
AST_JB_LOG

Definition at line 42 of file abstract_jb.h.

     {
   AST_JB_ENABLED = (1 << 0),
   AST_JB_FORCED =  (1 << 1),
   AST_JB_LOG =     (1 << 2)
};

---

Function Documentation

void ast_jb_configure	(	struct ast_channel *	chan,
		const struct ast_jb_conf *	conf
	)

Configures a jitterbuffer on a channel.

Parameters:

	chan	channel to configure.
	conf	configuration to apply.

Called from a channel driver when a channel is created and its jitterbuffer needs to be configured.

Definition at line 610 of file abstract_jb.c.

References ast_jb::conf, and ast_channel::jb.

Referenced by __oh323_rtp_create(), __oh323_update_info(), alsa_new(), console_new(), dahdi_new(), gtalk_new(), jingle_new(), local_new(), mgcp_new(), misdn_new(), oss_new(), sip_new(), skinny_new(), unistim_new(), and usbradio_new().

{
   memcpy(&chan->jb.conf, conf, sizeof(*conf));
}

void ast_jb_destroy

(

struct ast_channel *

chan

)

Destroys jitterbuffer on a channel.

Parameters:

chan

channel.

Called from ast_channel_free() when a channel is destroyed.

Definition at line 530 of file abstract_jb.c.

References ast_clear_flag, ast_frfree, ast_test_flag, ast_verb, ast_jb_impl::destroy, f, ast_jb::impl, ast_channel::jb, JB_CREATED, JB_IMPL_OK, ast_jb::jbobj, ast_jb::logfile, ast_channel::name, ast_jb_impl::name, and ast_jb_impl::remove.

Referenced by ast_channel_free().

{
   struct ast_jb *jb = &chan->jb;
   struct ast_jb_impl *jbimpl = jb->impl;
   void *jbobj = jb->jbobj;
   struct ast_frame *f;

   if (jb->logfile) {
      fclose(jb->logfile);
      jb->logfile = NULL;
   }

   if (ast_test_flag(jb, JB_CREATED)) {
      /* Remove and free all frames still queued in jb */
      while (jbimpl->remove(jbobj, &f) == JB_IMPL_OK) {
         ast_frfree(f);
      }

      jbimpl->destroy(jbobj);
      jb->jbobj = NULL;

      ast_clear_flag(jb, JB_CREATED);

      ast_verb(3, "%s jitterbuffer destroyed on channel %s\n", jbimpl->name, chan->name);
   }
}

int ast_jb_do_usecheck	(	struct ast_channel *	c0,
		struct ast_channel *	c1
	)

Checks the need of a jb use in a generic bridge.

Parameters:

	c0	first bridged channel.
	c1	second bridged channel.

Called from ast_generic_bridge() when two channels are entering in a bridge. The function checks the need of a jitterbuffer, depending on both channel's configuration and technology properties. As a result, this function sets appropriate internal jb flags to the channels, determining further behaviour of the bridged jitterbuffers.

Return values:

	zero	if there are no jitter buffers in use
	non-zero	if there are

Definition at line 202 of file abstract_jb.c.

References AST_CHAN_TP_CREATESJITTER, AST_CHAN_TP_WANTSJITTER, AST_JB_ENABLED, AST_JB_FORCED, ast_set_flag, ast_test_flag, ast_jb::conf, inuse, ast_channel::jb, jb_choose_impl(), JB_CREATED, JB_TIMEBASE_INITIALIZED, JB_USE, ast_channel_tech::properties, ast_channel::tech, and ast_jb::timebase.

Referenced by ast_generic_bridge().

{
   struct ast_jb *jb0 = &c0->jb;
   struct ast_jb *jb1 = &c1->jb;
   struct ast_jb_conf *conf0 = &jb0->conf;
   struct ast_jb_conf *conf1 = &jb1->conf;
   int c0_wants_jitter = c0->tech->properties & AST_CHAN_TP_WANTSJITTER;
   int c0_creates_jitter = c0->tech->properties & AST_CHAN_TP_CREATESJITTER;
   int c0_jb_enabled = ast_test_flag(conf0, AST_JB_ENABLED);
   int c0_force_jb = ast_test_flag(conf0, AST_JB_FORCED);
   int c0_jb_timebase_initialized = ast_test_flag(jb0, JB_TIMEBASE_INITIALIZED);
   int c0_jb_created = ast_test_flag(jb0, JB_CREATED);
   int c1_wants_jitter = c1->tech->properties & AST_CHAN_TP_WANTSJITTER;
   int c1_creates_jitter = c1->tech->properties & AST_CHAN_TP_CREATESJITTER;
   int c1_jb_enabled = ast_test_flag(conf1, AST_JB_ENABLED);
   int c1_force_jb = ast_test_flag(conf1, AST_JB_FORCED);
   int c1_jb_timebase_initialized = ast_test_flag(jb1, JB_TIMEBASE_INITIALIZED);
   int c1_jb_created = ast_test_flag(jb1, JB_CREATED);
   int inuse = 0;

   /* Determine whether audio going to c0 needs a jitter buffer */
   if (((!c0_wants_jitter && c1_creates_jitter) || (c0_force_jb && c1_creates_jitter)) && c0_jb_enabled) {
      ast_set_flag(jb0, JB_USE);
      if (!c0_jb_timebase_initialized) {
         if (c1_jb_timebase_initialized) {
            memcpy(&jb0->timebase, &jb1->timebase, sizeof(struct timeval));
         } else {
            gettimeofday(&jb0->timebase, NULL);
         }
         ast_set_flag(jb0, JB_TIMEBASE_INITIALIZED);
      }

      if (!c0_jb_created) {
         jb_choose_impl(c0);
      }

      inuse = 1;
   }

   /* Determine whether audio going to c1 needs a jitter buffer */
   if (((!c1_wants_jitter && c0_creates_jitter) || (c1_force_jb && c0_creates_jitter)) && c1_jb_enabled) {
      ast_set_flag(jb1, JB_USE);
      if (!c1_jb_timebase_initialized) {
         if (c0_jb_timebase_initialized) {
            memcpy(&jb1->timebase, &jb0->timebase, sizeof(struct timeval));
         } else {
            gettimeofday(&jb1->timebase, NULL);
         }
         ast_set_flag(jb1, JB_TIMEBASE_INITIALIZED);
      }

      if (!c1_jb_created) {
         jb_choose_impl(c1);
      }

      inuse = 1;
   }

   return inuse;
}

void ast_jb_empty_and_reset	(	struct ast_channel *	c0,
		struct ast_channel *	c1
	)

drops all frames from a jitterbuffer and resets it

Parameters:

	c0	one channel of a bridge
	c1	the other channel of the bridge

Definition at line 621 of file abstract_jb.c.

References ast_test_flag, ast_jb_impl::empty_and_reset, ast_jb::impl, ast_channel::jb, JB_CREATED, JB_USE, and ast_jb::jbobj.

Referenced by ast_generic_bridge().

{
   struct ast_jb *jb0 = &c0->jb;
   struct ast_jb *jb1 = &c1->jb;
   int c0_use_jb = ast_test_flag(jb0, JB_USE);
   int c0_jb_is_created = ast_test_flag(jb0, JB_CREATED);
   int c1_use_jb = ast_test_flag(jb1, JB_USE);
   int c1_jb_is_created = ast_test_flag(jb1, JB_CREATED);

   if (c0_use_jb && c0_jb_is_created && jb0->impl->empty_and_reset) {
      jb0->impl->empty_and_reset(jb0->jbobj);
   }

   if (c1_use_jb && c1_jb_is_created && jb1->impl->empty_and_reset) {
      jb1->impl->empty_and_reset(jb1->jbobj);
   }
}

void ast_jb_get_and_deliver	(	struct ast_channel *	c0,
		struct ast_channel *	c1
	)

Deliver the queued frames that should be delivered now for both channels.

Parameters:

	c0	first bridged channel.
	c1	second bridged channel.

Called from ast_generic_bridge() to deliver any frames, that should be delivered for the moment of invocation. Does nothing if neihter of the channels is using jb or has any frames currently queued in. The function delivers frames usig ast_write() each of the channels.

Definition at line 368 of file abstract_jb.c.

References ast_test_flag, ast_channel::jb, JB_CREATED, jb_get_and_deliver(), and JB_USE.

Referenced by ast_generic_bridge().

{
   struct ast_jb *jb0 = &c0->jb;
   struct ast_jb *jb1 = &c1->jb;
   int c0_use_jb = ast_test_flag(jb0, JB_USE);
   int c0_jb_is_created = ast_test_flag(jb0, JB_CREATED);
   int c1_use_jb = ast_test_flag(jb1, JB_USE);
   int c1_jb_is_created = ast_test_flag(jb1, JB_CREATED);

   if (c0_use_jb && c0_jb_is_created)
      jb_get_and_deliver(c0);

   if (c1_use_jb && c1_jb_is_created)
      jb_get_and_deliver(c1);
}

void ast_jb_get_config	(	const struct ast_channel *	chan,
		struct ast_jb_conf *	conf
	)

Copies a channel's jitterbuffer configuration.

Parameters:

	chan	channel.
	conf	destination.

Definition at line 616 of file abstract_jb.c.

References ast_jb::conf, and ast_channel::jb.

{
   memcpy(conf, &chan->jb.conf, sizeof(*conf));
}

int ast_jb_get_when_to_wakeup	(	struct ast_channel *	c0,
		struct ast_channel *	c1,
		int	time_left
	)

Calculates the time, left to the closest delivery moment in a bridge.

Parameters:

	c0	first bridged channel.
	c1	second bridged channel.
	time_left	bridge time limit, or -1 if not set.

Called from ast_generic_bridge() to determine the maximum time to wait for activity in ast_waitfor_n() call. If neihter of the channels is using jb, this function returns the time limit passed.

Returns:

maximum time to wait.

Definition at line 263 of file abstract_jb.c.

References ast_test_flag, get_now(), ast_channel::jb, JB_CREATED, JB_USE, and ast_jb::next.

Referenced by ast_generic_bridge().

{
   struct ast_jb *jb0 = &c0->jb;
   struct ast_jb *jb1 = &c1->jb;
   int c0_use_jb = ast_test_flag(jb0, JB_USE);
   int c0_jb_is_created = ast_test_flag(jb0, JB_CREATED);
   int c1_use_jb = ast_test_flag(jb1, JB_USE);
   int c1_jb_is_created = ast_test_flag(jb1, JB_CREATED);
   int wait, wait0, wait1;
   struct timeval tv_now;

   if (time_left == 0) {
      /* No time left - the bridge will be retried */
      /* TODO: Test disable this */
      /*return 0;*/
   }

   if (time_left < 0) {
      time_left = INT_MAX;
   }

   gettimeofday(&tv_now, NULL);

   wait0 = (c0_use_jb && c0_jb_is_created) ? jb0->next - get_now(jb0, &tv_now) : time_left;
   wait1 = (c1_use_jb && c1_jb_is_created) ? jb1->next - get_now(jb1, &tv_now) : time_left;

   wait = wait0 < wait1 ? wait0 : wait1;
   wait = wait < time_left ? wait : time_left;

   if (wait == INT_MAX) {
      wait = -1;
   } else if (wait < 1) {
      /* don't let wait=0, because this can cause the pbx thread to loop without any sleeping at all */
      wait = 1;
   }

   return wait;
}

int ast_jb_put	(	struct ast_channel *	chan,
		struct ast_frame *	f
	)

Puts a frame into a channel jitterbuffer.

Parameters:

	chan	channel.
	f	frame.

Called from ast_generic_bridge() to put a frame into a channel's jitterbuffer. The function will successfuly enqueue a frame if and only if: 1. the channel is using a jitterbuffer (as determined by ast_jb_do_usecheck()), 2. the frame's type is AST_FRAME_VOICE, 3. the frame has timing info set and has length >= 2 ms, 4. there is no some internal error happened (like failed memory allocation). Frames, successfuly queued, should be delivered by the channel's jitterbuffer, when their delivery time has came. Frames, not successfuly queued, should be delivered immediately. Dropped by the jb implementation frames are considered successfuly enqueued as far as they should not be delivered at all.

Return values:

	0	if the frame was queued
	-1	if not

Definition at line 303 of file abstract_jb.c.

References ast_clear_flag, AST_FRAME_DTMF, AST_FRAME_VOICE, ast_frdup(), AST_FRFLAG_HAS_TIMING_INFO, ast_frfree, ast_log(), ast_set_flag, ast_test_flag, create_jb(), ast_jb_impl::force_resync, ast_frame::frametype, get_now(), ast_jb::impl, ast_channel::jb, JB_CREATED, jb_framelog, JB_IMPL_OK, JB_USE, ast_jb::jbobj, ast_frame::len, LOG_ERROR, LOG_WARNING, ast_channel::name, ast_jb_impl::next, ast_jb::next, ast_jb_impl::put, ast_frame::src, and ast_frame::ts.

Referenced by ast_generic_bridge().

{
   struct ast_jb *jb = &chan->jb;
   struct ast_jb_impl *jbimpl = jb->impl;
   void *jbobj = jb->jbobj;
   struct ast_frame *frr;
   long now = 0;

   if (!ast_test_flag(jb, JB_USE))
      return -1;

   if (f->frametype != AST_FRAME_VOICE) {
      if (f->frametype == AST_FRAME_DTMF && ast_test_flag(jb, JB_CREATED)) {
         jb_framelog("JB_PUT {now=%ld}: Received DTMF frame. Force resynching jb...\n", now);
         jbimpl->force_resync(jbobj);
      }

      return -1;
   }

   /* We consider an enabled jitterbuffer should receive frames with valid timing info. */
   if (!ast_test_flag(f, AST_FRFLAG_HAS_TIMING_INFO) || f->len < 2 || f->ts < 0) {
      ast_log(LOG_WARNING, "%s received frame with invalid timing info: "
         "has_timing_info=%d, len=%ld, ts=%ld, src=%s\n",
         chan->name, ast_test_flag(f, AST_FRFLAG_HAS_TIMING_INFO), f->len, f->ts, f->src);
      return -1;
   }

   frr = ast_frdup(f);

   if (!frr) {
      ast_log(LOG_ERROR, "Failed to isolate frame for the jitterbuffer on channel '%s'\n", chan->name);
      return -1;
   }

   if (!ast_test_flag(jb, JB_CREATED)) {
      if (create_jb(chan, frr)) {
         ast_frfree(frr);
         /* Disable the jitterbuffer */
         ast_clear_flag(jb, JB_USE);
         return -1;
      }

      ast_set_flag(jb, JB_CREATED);
      return 0;
   } else {
      now = get_now(jb, NULL);
      if (jbimpl->put(jbobj, frr, now) != JB_IMPL_OK) {
         jb_framelog("JB_PUT {now=%ld}: Dropped frame with ts=%ld and len=%ld\n", now, frr->ts, frr->len);
         ast_frfree(frr);
         /*return -1;*/
         /* TODO: Check this fix - should return 0 here, because the dropped frame shouldn't
            be delivered at all */
         return 0;
      }

      jb->next = jbimpl->next(jbobj);

      jb_framelog("JB_PUT {now=%ld}: Queued frame with ts=%ld and len=%ld\n", now, frr->ts, frr->len);

      return 0;
   }
}

int ast_jb_read_conf	(	struct ast_jb_conf *	conf,
		const char *	varname,
		const char *	value
	)

Sets jitterbuffer configuration property.

Parameters:

	conf	configuration to store the property in.
	varname	property name.
	value	property value.

Called from a channel driver to build a jitterbuffer configuration typically when reading a configuration file. It is not necessary for a channel driver to know each of the jb configuration property names. The jitterbuffer itself knows them. The channel driver can pass each config var it reads through this function. It will return 0 if the variable was consumed from the jb conf.

Returns:

zero if the property was set to the configuration, -1 if not.

Definition at line 571 of file abstract_jb.c.

References AST_JB_CONF_ENABLE, AST_JB_CONF_FORCE, AST_JB_CONF_IMPL, AST_JB_CONF_LOG, AST_JB_CONF_MAX_SIZE, AST_JB_CONF_PREFIX, AST_JB_CONF_RESYNCH_THRESHOLD, AST_JB_CONF_TARGET_EXTRA, AST_JB_ENABLED, AST_JB_FORCED, AST_JB_LOG, ast_set2_flag, ast_strlen_zero(), ast_true(), ast_jb_conf::impl, ast_jb_conf::max_size, name, ast_jb_conf::resync_threshold, and ast_jb_conf::target_extra.

Referenced by _build_general_config(), config_parse_variables(), gtalk_load_config(), jingle_load_config(), load_module(), process_dahdi(), reload_config(), store_config(), and store_config_core().

{
   int prefixlen = sizeof(AST_JB_CONF_PREFIX) - 1;
   const char *name;
   int tmp;

   if (strncasecmp(AST_JB_CONF_PREFIX, varname, prefixlen)) {
      return -1;
   }

   name = varname + prefixlen;

   if (!strcasecmp(name, AST_JB_CONF_ENABLE)) {
      ast_set2_flag(conf, ast_true(value), AST_JB_ENABLED);
   } else if (!strcasecmp(name, AST_JB_CONF_FORCE)) {
      ast_set2_flag(conf, ast_true(value), AST_JB_FORCED);
   } else if (!strcasecmp(name, AST_JB_CONF_MAX_SIZE)) {
      if ((tmp = atoi(value)) > 0)
         conf->max_size = tmp;
   } else if (!strcasecmp(name, AST_JB_CONF_RESYNCH_THRESHOLD)) {
      if ((tmp = atoi(value)) > 0)
         conf->resync_threshold = tmp;
   } else if (!strcasecmp(name, AST_JB_CONF_IMPL)) {
      if (!ast_strlen_zero(value))
         snprintf(conf->impl, sizeof(conf->impl), "%s", value);
   } else if (!strcasecmp(name, AST_JB_CONF_TARGET_EXTRA)) {
      if (sscanf(value, "%30d", &tmp) == 1) {
         conf->target_extra = tmp;
      }
   } else if (!strcasecmp(name, AST_JB_CONF_LOG)) {
      ast_set2_flag(conf, ast_true(value), AST_JB_LOG);
   } else {
      return -1;
   }

   return 0;
}