Пример #1
0
int ast_slinfactory_feed(struct ast_slinfactory *sf, struct ast_frame *f)
{
	struct ast_frame *begin_frame = f, *duped_frame = NULL, *frame_ptr;
	unsigned int x;

	/* In some cases, we can be passed a frame which has no data in it, but
	 * which has a positive number of samples defined. Once such situation is
	 * when a jitter buffer is in use and the jitter buffer interpolates a frame.
	 * The frame it produces has data set to NULL, datalen set to 0, and samples
	 * set to either 160 or 240.
	 */
	if (!f->data) {
		return 0;
	}

	if (f->subclass != AST_FORMAT_SLINEAR) {
		if (sf->trans && f->subclass != sf->format) {
			ast_translator_free_path(sf->trans);
			sf->trans = NULL;
		}

		if (!sf->trans) {
			if ((sf->trans = ast_translator_build_path(AST_FORMAT_SLINEAR, f->subclass)) == NULL) {
				ast_log(LOG_WARNING, "Cannot build a path from %s to slin\n", ast_getformatname(f->subclass));
				return 0;
			} else {
				sf->format = f->subclass;
			}
		}

		if (!(begin_frame = ast_translate(sf->trans, f, 0))) 
			return 0;
		
		duped_frame = ast_frdup(begin_frame);

		ast_frfree(begin_frame);

		if (!duped_frame)
			return 0;
	} else {
		if (!(duped_frame = ast_frdup(f)))
			return 0;
	}

	x = 0;
	AST_LIST_TRAVERSE(&sf->queue, frame_ptr, frame_list)
		x++;

	AST_LIST_INSERT_TAIL(&sf->queue, duped_frame, frame_list);

	sf->size += duped_frame->samples;

	return x;
}
Пример #2
0
int ast_slinfactory_feed(struct ast_slinfactory *sf, struct ast_frame *f)
{
	struct ast_frame *frame, *frame_ptr;

	if (!f) {
		return 0;
	}

	if (f->subclass != AST_FORMAT_SLINEAR) {
		if (sf->trans && f->subclass != sf->format) {
			ast_translator_free_path(sf->trans);
			sf->trans = NULL;
		}
		if (!sf->trans) {
			if ((sf->trans = ast_translator_build_path(AST_FORMAT_SLINEAR, f->subclass)) == NULL) {
				ast_log(LOG_WARNING, "Cannot build a path from %s to slin\n", ast_getformatname(f->subclass));
				return 0;
			} else {
				sf->format = f->subclass;
			}
		}
	}

	if (sf->trans) {
		frame = ast_translate(sf->trans, f, 0);
	} else {
		frame = ast_frdup(f);
	}

	if (frame) {
		int x = 0;
		for (frame_ptr = sf->queue; frame_ptr && frame_ptr->next; frame_ptr=frame_ptr->next) {
			x++;
		}
		if (frame_ptr) {
			frame_ptr->next = frame;
		} else {
			sf->queue = frame;
		}
		frame->next = NULL;
		sf->size += frame->datalen;	
		return x;
	}

	return 0;
	
}
Пример #3
0
/*! \brief Allocator for T.38 data */
static struct t38_parameters_task_data *t38_parameters_task_data_alloc(struct ast_sip_session *session,
	struct ast_frame *frame)
{
	struct t38_parameters_task_data *data = ao2_alloc(sizeof(*data), t38_parameters_task_data_destroy);

	if (!data) {
		return NULL;
	}

	data->session = session;
	ao2_ref(session, +1);
	data->frame = ast_frdup(frame);
	if (!data->frame) {
		ao2_ref(data, -1);
		data = NULL;
	}

	return data;
}
Пример #4
0
conf_frame* create_conf_frame( struct ast_conf_member* member, conf_frame* next, const struct ast_frame* fr )
{
    // pointer to list of mixed frames
    conf_frame* cf = malloc( sizeof( struct conf_frame ) ) ;

    if ( cf == NULL )
    {
        ast_log( LOG_ERROR, "unable to allocate memory for conf frame\n" ) ;
        return NULL ;
    }

    //
    // init with some defaults
    //

    // make sure converted frames are set to null
//	for ( int c = 0 ; c < AC_SUPPORTED_FORMATS ; ++c )
//	{
//		cf->converted[ c ] = NULL ;
//	}

    memset( (struct ast_frame*)( cf->converted ), 0x0, ( sizeof( struct ast_frame* ) * AC_SUPPORTED_FORMATS ) ) ;

    cf->member = member ;
    // cf->priority = 0 ;

    cf->prev = NULL ;
    cf->next = next ;

    cf->static_frame = 0 ;

    // establish relationship to 'next'
    if ( next != NULL ) next->prev = cf ;

    // this holds the ast_frame pointer
    cf->fr = ( fr == NULL ) ? NULL : ast_frdup( ( struct ast_frame* )( fr ) ) ;

    // this holds the temporu mix buffer
    cf->mixed_buffer = NULL ;

    return cf ;
}
Пример #5
0
static int transmit_audio(fax_session *s)
{
	int res = -1;
	int original_read_fmt = AST_FORMAT_SLINEAR;
	int original_write_fmt = AST_FORMAT_SLINEAR;
	fax_state_t fax;
	struct ast_dsp *dsp = NULL;
	int detect_tone = 0;
	struct ast_frame *inf = NULL;
	struct ast_frame *fr;
	int last_state = 0;
	struct timeval now, start, state_change;
	enum ast_control_t38 t38control;

	original_read_fmt = s->chan->readformat;
	if (original_read_fmt != AST_FORMAT_SLINEAR) {
		res = ast_set_read_format(s->chan, AST_FORMAT_SLINEAR);
		if (res < 0) {
			ast_log(LOG_WARNING, "Unable to set to linear read mode, giving up\n");
			goto done;
		}
	}

	original_write_fmt = s->chan->writeformat;
	if (original_write_fmt != AST_FORMAT_SLINEAR) {
		res = ast_set_write_format(s->chan, AST_FORMAT_SLINEAR);
		if (res < 0) {
			ast_log(LOG_WARNING, "Unable to set to linear write mode, giving up\n");
			goto done;
		}
	}

	/* Initialize T30 terminal */
	fax_init(&fax, s->caller_mode);

	/* Setup logging */
	set_logging(&fax.logging);
	set_logging(&fax.t30_state.logging);

	/* Configure terminal */
	set_local_info(&fax.t30_state, s);
	set_file(&fax.t30_state, s);
	set_ecm(&fax.t30_state, TRUE);

	fax_set_transmit_on_idle(&fax, TRUE);

	t30_set_phase_e_handler(&fax.t30_state, phase_e_handler, s);

	if (s->t38state == T38_STATE_UNAVAILABLE) {
		ast_debug(1, "T38 is unavailable on %s\n", s->chan->name);
	} else if (!s->direction) {
		/* We are receiving side and this means we are the side which should
		   request T38 when the fax is detected. Use DSP to detect fax tone */
		ast_debug(1, "Setting up CNG detection on %s\n", s->chan->name);
		dsp = ast_dsp_new();
		ast_dsp_set_features(dsp, DSP_FEATURE_FAX_DETECT);
		ast_dsp_set_faxmode(dsp, DSP_FAXMODE_DETECT_CNG);
		detect_tone = 1;
	}

	start = state_change = ast_tvnow();

	ast_activate_generator(s->chan, &generator, &fax);

	while (!s->finished) {
		res = ast_waitfor(s->chan, 20);
		if (res < 0)
			break;
		else if (res > 0)
			res = 0;

		inf = ast_read(s->chan);
		if (inf == NULL) {
			ast_debug(1, "Channel hangup\n");
			res = -1;
			break;
		}

		ast_debug(10, "frame %d/%d, len=%d\n", inf->frametype, inf->subclass, inf->datalen);

		/* Detect fax tone */
		if (detect_tone && inf->frametype == AST_FRAME_VOICE) {
			/* Duplicate frame because ast_dsp_process may free the frame passed */
			fr = ast_frdup(inf);

			/* Do not pass channel to ast_dsp_process otherwise it may queue modified audio frame back */
			fr = ast_dsp_process(NULL, dsp, fr);
			if (fr && fr->frametype == AST_FRAME_DTMF && fr->subclass == 'f') {
				ast_debug(1, "Fax tone detected. Requesting T38\n");
				t38control = AST_T38_REQUEST_NEGOTIATE;
				ast_indicate_data(s->chan, AST_CONTROL_T38, &t38control, sizeof(t38control));
				detect_tone = 0;
			}

			ast_frfree(fr);
		}


		/* Check the frame type. Format also must be checked because there is a chance
		   that a frame in old format was already queued before we set chanel format
		   to slinear so it will still be received by ast_read */
		if (inf->frametype == AST_FRAME_VOICE && inf->subclass == AST_FORMAT_SLINEAR) {

			if (fax_rx(&fax, inf->data, inf->samples) < 0) {
				/* I know fax_rx never returns errors. The check here is for good style only */
				ast_log(LOG_WARNING, "fax_rx returned error\n");
				res = -1;
				break;
			}

			/* Watchdog */
			if (last_state != fax.t30_state.state) {
				state_change = ast_tvnow();
				last_state = fax.t30_state.state;
			}
		} else if (inf->frametype == AST_FRAME_CONTROL && inf->subclass == AST_CONTROL_T38 &&
				inf->datalen == sizeof(enum ast_control_t38)) {
			t38control =*((enum ast_control_t38 *) inf->data);
			if (t38control == AST_T38_NEGOTIATED) {
				/* T38 switchover completed */
				ast_debug(1, "T38 negotiated, finishing audio loop\n");
				res = 1;
				break;
			}
		}

		ast_frfree(inf);
		inf = NULL;

		/* Watchdog */
		now = ast_tvnow();
		if (ast_tvdiff_sec(now, start) > WATCHDOG_TOTAL_TIMEOUT || ast_tvdiff_sec(now, state_change) > WATCHDOG_STATE_TIMEOUT) {
			ast_log(LOG_WARNING, "It looks like we hung. Aborting.\n");
			res = -1;
			break;
		}
	}

	ast_debug(1, "Loop finished, res=%d\n", res);

	if (inf)
		ast_frfree(inf);

	if (dsp)
		ast_dsp_free(dsp);

	ast_deactivate_generator(s->chan);

	/* If we are switching to T38, remove phase E handler. Otherwise it will be executed
	   by t30_terminate, display diagnostics and set status variables although no transmittion
	   has taken place yet. */
	if (res > 0) {
		t30_set_phase_e_handler(&fax.t30_state, NULL, NULL);
	}

	t30_terminate(&fax.t30_state);
	fax_release(&fax);

done:
	if (original_write_fmt != AST_FORMAT_SLINEAR) {
		if (ast_set_write_format(s->chan, original_write_fmt) < 0)
			ast_log(LOG_WARNING, "Unable to restore write format on '%s'\n", s->chan->name);
	}

	if (original_read_fmt != AST_FORMAT_SLINEAR) {
		if (ast_set_read_format(s->chan, original_read_fmt) < 0)
			ast_log(LOG_WARNING, "Unable to restore read format on '%s'\n", s->chan->name);
	}

	return res;

}
Пример #6
0
static int nv_detectfax_exec(struct ast_channel *chan, void *data)
{
	int res = 0;
	struct ast_module_user *u;
	char tmp[256] = "\0";
	char *p = NULL;
	char *waitstr = NULL;
	char *options = NULL;
	char *silstr = NULL;
	char *minstr = NULL;
	char *maxstr = NULL;
	struct ast_frame *fr = NULL;
	struct ast_frame *fr2 = NULL;
	int notsilent = 0;
	struct timeval start = {0, 0}, end = {0, 0};
	int waitdur = 4;
	int sildur = 1000;
	int mindur = 100;
	int maxdur = -1;
	int skipanswer = 0;
	int noextneeded = 0;
	int ignoredtmf = 0;
	int ignorefax = 0;
	int ignoretalk = 0;
	int x = 0;
	int origrformat = 0;
	int features = 0;
	time_t timeout = 0;
	struct ast_dsp *dsp = NULL;

	pbx_builtin_setvar_helper(chan, "FAX_DETECTED", "");
	pbx_builtin_setvar_helper(chan, "FAXEXTEN", "");
	pbx_builtin_setvar_helper(chan, "DTMF_DETECTED", "");
	pbx_builtin_setvar_helper(chan, "TALK_DETECTED", "");

	if (data || !ast_strlen_zero((char *)data)) {
		strncpy(tmp, (char *)data, sizeof(tmp)-1);
	}

	p = tmp;

	waitstr = strsep(&p, "|");
	options = strsep(&p, "|");
	silstr = strsep(&p, "|");
	minstr = strsep(&p, "|");
	maxstr = strsep(&p, "|");

	if (waitstr) {
		if ((sscanf(waitstr, "%d", &x) == 1) && (x > 0))
			waitdur = x;
	}

	if (options) {
		if (strchr(options, 'n'))
			skipanswer = 1;
		if (strchr(options, 'x'))
			noextneeded = 1;
		if (strchr(options, 'd'))
			ignoredtmf = 1;
		if (strchr(options, 'f'))
			ignorefax = 1;
		if (strchr(options, 't'))
			ignoretalk = 1;
	}

	if (silstr) {
		if ((sscanf(silstr, "%d", &x) == 1) && (x > 0))
			sildur = x;
	}

	if (minstr) {
		if ((sscanf(minstr, "%d", &x) == 1) && (x > 0))
			mindur = x;
	}

	if (maxstr) {
		if ((sscanf(maxstr, "%d", &x) == 1) && (x > 0))
			maxdur = x;
	}

	ast_log(LOG_DEBUG, "Preparing detect of fax (waitdur=%ds, sildur=%dms, mindur=%dms, maxdur=%dms)\n",
						waitdur, sildur, mindur, maxdur);

	u = ast_module_user_add(chan);

	if (chan->_state != AST_STATE_UP && !skipanswer) {
		/* Otherwise answer unless we're supposed to send this while on-hook */
		res = ast_answer(chan);
	}
	if (!res) {
		origrformat = chan->readformat;
		if ((res = ast_set_read_format(chan, AST_FORMAT_SLINEAR)))
			ast_log(LOG_WARNING, "Unable to set read format to linear!\n");
	}
	if (!(dsp = ast_dsp_new())) {
		ast_log(LOG_WARNING, "Unable to allocate DSP!\n");
		res = -1;
	}

	if (dsp) {
#if 0
		if (!ignoretalk)
			; /* features |= DSP_FEATURE_SILENCE_SUPPRESS; */
#endif
		if (!ignorefax)
			features |= DSP_FEATURE_FAX_DETECT;
		if (!ignoredtmf)
			features |= DSP_FEATURE_DTMF_DETECT;

		ast_dsp_set_threshold(dsp, 256);
		ast_dsp_set_features(dsp, features | DSP_DIGITMODE_RELAXDTMF);
		ast_dsp_digitmode(dsp, DSP_DIGITMODE_DTMF);
	}

	if (!res) {
		if (waitdur > 0)
			timeout = time(NULL) + (time_t)waitdur;

		while (ast_waitfor(chan, 50) > -1) {
			if (waitdur > 0 && time(NULL) > timeout) {
				res = 0;
				break;
			}

			fr = ast_read(chan);
			if (!fr) {
				ast_log(LOG_DEBUG, "Got hangup\n");
				res = -1;
				break;
			}

			/* Duplicate frame because ast_dsp_process may free the frame passed */
			fr2 = ast_frdup(fr);

			/* Do not pass channel to ast_dsp_process otherwise it may queue modified audio frame back */
			fr2 = ast_dsp_process(NULL, dsp, fr2);
			if (!fr2) {
				ast_log(LOG_ERROR, "Bad DSP received (what happened?)\n");
				ast_frfree(fr);
				res = 0;
				break;
			}

			if (fr2->frametype == AST_FRAME_DTMF) {
				if (fr2->subclass == 'f' && !ignorefax) {
					/* Fax tone -- Handle and return NULL */
					ast_log(LOG_DEBUG, "Fax detected on %s\n", chan->name);
					if (strcmp(chan->exten, "fax")) {
						ast_log(LOG_NOTICE, "Redirecting '%s' to fax extension on context '%s'\n", chan->name, chan->context);
						pbx_builtin_setvar_helper(chan, "FAX_DETECTED", "1");
						pbx_builtin_setvar_helper(chan, "FAXEXTEN", chan->exten);

						if (ast_exists_extension(chan, chan->context, "fax", 1, chan->CALLERID_FIELD)) {
							/* Save the DID/DNIS when we transfer the fax call to a "fax" extension */
							strncpy(chan->exten, "fax", sizeof(chan->exten)-1);
							chan->priority = 0;
						} else
							ast_log(LOG_WARNING, "Fax detected, but no fax extension\n");
					} else
						ast_log(LOG_WARNING, "Already in a fax extension, not redirecting\n");

					res = 0;
					ast_frfree(fr);
					ast_frfree(fr2);
					break;
				} else if (!ignoredtmf) {
					ast_log(LOG_DEBUG, "DTMF detected on %s\n", chan->name);
					char t[2];
					t[0] = fr2->subclass;
					t[1] = '\0';
					if (noextneeded || ast_canmatch_extension(chan, chan->context, t, 1, chan->CALLERID_FIELD)) {
						pbx_builtin_setvar_helper(chan, "DTMF_DETECTED", "1");
						/* They entered a valid extension, or might be anyhow */
						if (noextneeded) {
							ast_log(LOG_NOTICE, "DTMF received (not matching to exten)\n");
							res = 0;
						} else {
							ast_log(LOG_NOTICE, "DTMF received (matching to exten)\n");
							res = fr2->subclass;
						}
						ast_frfree(fr);
						ast_frfree(fr2);
						break;
					} else
						ast_log(LOG_DEBUG, "Valid extension requested and DTMF did not match\n");
				}
			} else if ((fr->frametype == AST_FRAME_VOICE) && (fr->subclass == AST_FORMAT_SLINEAR) && !ignoretalk) {
				int totalsilence;
				int ms;
				res = ast_dsp_silence(dsp, fr, &totalsilence);
				if (res && (totalsilence > sildur)) {
					/* We've been quiet a little while */
					if (notsilent) {
						/* We had heard some talking */
						gettimeofday(&end, NULL);
						ms = (end.tv_sec - start.tv_sec) * 1000;
						ms += (end.tv_usec - start.tv_usec) / 1000;
						ms -= sildur;
						if (ms < 0)
							ms = 0;
						if ((ms > mindur) && ((maxdur < 0) || (ms < maxdur))) {
							char ms_str[10];
							ast_log(LOG_DEBUG, "Found qualified token of %d ms\n", ms);
							ast_log(LOG_NOTICE, "Redirecting %s to talk extension\n", chan->name);

							/* Save detected talk time (in milliseconds) */
							sprintf(ms_str, "%d", ms);
							pbx_builtin_setvar_helper(chan, "TALK_DETECTED", ms_str);

							if (ast_exists_extension(chan, chan->context, "talk", 1, chan->CALLERID_FIELD)) {
								strncpy(chan->exten, "talk", sizeof(chan->exten) - 1);
								chan->priority = 0;
							} else
								ast_log(LOG_WARNING, "Talk detected, but no talk extension\n");
							res = 0;
							ast_frfree(fr);
							ast_frfree(fr2);
							break;
						} else
							ast_log(LOG_DEBUG, "Found unqualified token of %d ms\n", ms);
						notsilent = 0;
					}
				} else {
					if (!notsilent) {
						/* Heard some audio, mark the begining of the token */
						gettimeofday(&start, NULL);
						ast_log(LOG_DEBUG, "Start of voice token!\n");
						notsilent = 1;
					}
				}
			}
			ast_frfree(fr);
			ast_frfree(fr2);
		}
	} else
		ast_log(LOG_WARNING, "Could not answer channel '%s'\n", chan->name);

	if (res > -1) {
		if (origrformat && ast_set_read_format(chan, origrformat)) {
			ast_log(LOG_WARNING, "Failed to restore read format for %s to %s\n",
				chan->name, ast_getformatname(origrformat));
		}
	}

	if (dsp)
		ast_dsp_free(dsp);

	ast_module_user_remove(u);

	return res;
}
Пример #7
0
int ast_jb_put(struct ast_channel *chan, struct ast_frame *f)
{
	struct ast_jb *jb = ast_channel_jb(chan);
	const 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",
			ast_channel_name(chan), 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", ast_channel_name(chan));
		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) != AST_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;
	}
}
Пример #8
0
conf_frame* mix_single_speaker( conf_frame* frames_in, int volume )
{
#ifdef APP_KONFERENCE_DEBUG
    //DEBUG("returning single spoken frame\n") ;

    //
    // check input
    //

    if ( frames_in == NULL )
    {
        DEBUG("unable to mix single spoken frame with null frame\n") ;
        return NULL ;
    }

    if ( frames_in->fr == NULL )
    {
        DEBUG("unable to mix single spoken frame with null data\n") ;
        return NULL ;
    }

    if ( frames_in->member == NULL )
    {
        DEBUG("unable to mix single spoken frame with null member\n") ;
        return NULL ;
    }
#endif // APP_KONFERENCE_DEBUG

    //
    // 'mix' the frame
    //

    // copy orignal frame to converted array so listeners don't need to re-encode it
    frames_in->converted[ frames_in->member->read_format_index ] = ast_frdup( frames_in->fr ) ;

    // convert frame to slinear, if we have a path
    if (!(frames_in->fr = convert_frame_to_slinear( frames_in->member->to_slinear, frames_in->fr)))
    {
        ast_log( LOG_WARNING, "mix_single_speaker: unable to convert frame to slinear\n" ) ;
        return frames_in ;
    }

    if ( (frames_in->member->talk_volume != 0) || (volume != 0) )
    {
        ast_frame_adjust_volume(frames_in->fr, frames_in->member->talk_volume + volume);
    }

    if (!frames_in->member->spy_partner)
    {
        // speaker is neither a spyee nor a spyer
        // set the frame's member to null ( i.e. all listeners )
        frames_in->member = NULL ;
    }
    else
    {
        // speaker is either a spyee or a spyer
        if ( frames_in->member->spyee_channel_name == NULL )
        {
            conf_frame *spy_frame = copy_conf_frame(frames_in);

            if ( spy_frame != 0 )
            {
                frames_in->next = spy_frame;
                spy_frame->prev = frames_in;

                spy_frame->member = frames_in->member->spy_partner;
            }

            frames_in->member = NULL ;
        }
        else
            frames_in->member = frames_in->member->spy_partner ;
    }

    return frames_in ;
}
Пример #9
0
static struct ast_frame *hook_event_cb(struct ast_channel *chan, struct ast_frame *frame, enum ast_framehook_event event, void *data)
{
	struct jb_framedata *framedata = data;
	struct timeval now_tv;
	unsigned long now;
	int putframe = 0; /* signifies if audio frame was placed into the buffer or not */

	switch (event) {
	case AST_FRAMEHOOK_EVENT_READ:
		break;
	case AST_FRAMEHOOK_EVENT_ATTACHED:
	case AST_FRAMEHOOK_EVENT_DETACHED:
	case AST_FRAMEHOOK_EVENT_WRITE:
		return frame;
	}

	if (ast_channel_fdno(chan) == AST_JITTERBUFFER_FD && framedata->timer) {
		if (ast_timer_ack(framedata->timer, 1) < 0) {
			ast_log(LOG_ERROR, "Failed to acknowledge timer in jitter buffer\n");
			return frame;
		}
	}

	if (!frame) {
		return frame;
	}

	now_tv = ast_tvnow();
	now = ast_tvdiff_ms(now_tv, framedata->start_tv);

	if (frame->frametype == AST_FRAME_VOICE) {
		int res;
		struct ast_frame *jbframe;

		if (!ast_test_flag(frame, AST_FRFLAG_HAS_TIMING_INFO) || frame->len < 2 || frame->ts < 0) {
			/* only frames with timing info can enter the jitterbuffer */
			return frame;
		}

		jbframe = ast_frisolate(frame);
		ao2_replace(framedata->last_format, frame->subclass.format);

		if (frame->len && (frame->len != framedata->timer_interval)) {
			framedata->timer_interval = frame->len;
			ast_timer_set_rate(framedata->timer, 1000 / framedata->timer_interval);
		}
		if (!framedata->first) {
			framedata->first = 1;
			res = framedata->jb_impl->put_first(framedata->jb_obj, jbframe, now);
		} else {
			res = framedata->jb_impl->put(framedata->jb_obj, jbframe, now);
		}

		if (res == AST_JB_IMPL_OK) {
			if (jbframe != frame) {
				ast_frfree(frame);
			}
			frame = &ast_null_frame;
		} else if (jbframe != frame) {
			ast_frfree(jbframe);
		}
		putframe = 1;
	}

	if (frame->frametype == AST_FRAME_NULL) {
		int res;
		long next = framedata->jb_impl->next(framedata->jb_obj);

		/* If now is earlier than the next expected output frame
		 * from the jitterbuffer we may choose to pass on retrieving
		 * a frame during this read iteration.  The only exception
		 * to this rule is when an audio frame is placed into the buffer
		 * and the time for the next frame to come out of the buffer is
		 * at least within the timer_interval of the next output frame. By
		 * doing this we are able to feed off the timing of the input frames
		 * and only rely on our jitterbuffer timer when frames are dropped.
		 * During testing, this hybrid form of timing gave more reliable results. */
		if (now < next) {
			long int diff = next - now;
			if (!putframe) {
				return frame;
			} else if (diff >= framedata->timer_interval) {
				return frame;
			}
		}

		ast_frfree(frame);
		frame = &ast_null_frame;
		res = framedata->jb_impl->get(framedata->jb_obj, &frame, now, framedata->timer_interval);
		switch (res) {
		case AST_JB_IMPL_OK:
			/* got it, and pass it through */
			break;
		case AST_JB_IMPL_DROP:
			ast_frfree(frame);
			frame = &ast_null_frame;
			break;
		case AST_JB_IMPL_INTERP:
			if (framedata->last_format) {
				struct ast_frame tmp = { 0, };

				tmp.frametype = AST_FRAME_VOICE;
				tmp.subclass.format = framedata->last_format;
				/* example: 8000hz / (1000 / 20ms) = 160 samples */
				tmp.samples = ast_format_get_sample_rate(framedata->last_format) / (1000 / framedata->timer_interval);
				tmp.delivery = ast_tvadd(framedata->start_tv, ast_samp2tv(next, 1000));
				tmp.offset = AST_FRIENDLY_OFFSET;
				tmp.src  = "func_jitterbuffer interpolation";
				ast_frfree(frame);
				frame = ast_frdup(&tmp);
				break;
			}
			/* else fall through */
		case AST_JB_IMPL_NOFRAME:
			ast_frfree(frame);
			frame = &ast_null_frame;
			break;
		}
	}

	if (frame->frametype == AST_FRAME_CONTROL) {
		switch(frame->subclass.integer) {
		case AST_CONTROL_HOLD:
		case AST_CONTROL_UNHOLD:
		case AST_CONTROL_T38_PARAMETERS:
		case AST_CONTROL_SRCUPDATE:
		case AST_CONTROL_SRCCHANGE:
			framedata->jb_impl->force_resync(framedata->jb_obj);
			break;
		default:
			break;
		}
	}

	return frame;
}