diff options
Diffstat (limited to 'pjmedia/src/pjmedia/silencedet.c')
| -rw-r--r-- | pjmedia/src/pjmedia/silencedet.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/pjmedia/src/pjmedia/silencedet.c b/pjmedia/src/pjmedia/silencedet.c new file mode 100644 index 0000000..b6399ae --- /dev/null +++ b/pjmedia/src/pjmedia/silencedet.c @@ -0,0 +1,333 @@ +/* $Id: silencedet.c 3664 2011-07-19 03:42:28Z nanang $ */ +/* + * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) + * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include <pjmedia/silencedet.h> +#include <pjmedia/alaw_ulaw.h> +#include <pjmedia/errno.h> +#include <pj/assert.h> +#include <pj/log.h> +#include <pj/pool.h> +#include <pj/string.h> + +#define THIS_FILE "silencedet.c" + +#if 1 +# define TRACE_(x) PJ_LOG(5,x) +#else +# define TRACE_(x) +#endif + +/** + * This enumeration specifies operation mode of silence detector + */ +typedef enum pjmedia_silence_det_mode { + VAD_MODE_NONE, + VAD_MODE_FIXED, + VAD_MODE_ADAPTIVE +} pjmedia_silence_det_mode; + +/** + * Default settings + */ +#define DEF_RECALC_ON_VOICED 4000 /* Time to recalculate threshold + in voiced condition, in ms */ +#define DEF_RECALC_ON_SILENCE 2000 /* Time to recalculate threshold + in silence condition, in ms. */ +#define DEF_BEFORE_SILENCE 400 /* Silence time before really changing + state into SILENCE, in ms. */ +#define DEF_THRESHOLD 1000 /* Default threshold. */ + +/** + * This enumeration specifies the states of the silence detector. + */ +enum pjmedia_silence_det_state { + STATE_SILENCE, + STATE_START_SILENCE, + STATE_VOICED +}; + +/** + * This structure holds the silence detector state. + */ +struct pjmedia_silence_det +{ + char objname[PJ_MAX_OBJ_NAME]; /**< VAD name. */ + + int mode; /**< VAD mode. */ + unsigned ptime; /**< Frame time, in msec. */ + + unsigned threshold; /**< Current threshold level. */ + unsigned sum_level; /**< Total sum of recent level. */ + unsigned sum_cnt; /**< Number of level summed. */ + unsigned silence_timer; /**< Silence condition timer. */ + unsigned voiced_timer; /**< Voiced condition timer. */ + + enum pjmedia_silence_det_state state;/**< Silence detector state. */ + unsigned recalc_on_voiced; /**< Setting of time to recalc + threshold in voiced condition. */ + unsigned recalc_on_silence; /**< Setting of time to recalc + threshold in silence condition.*/ + unsigned before_silence; /**< Setting of silence time before + really changing state into SILENCE, + in ms. */ +}; + + + +PJ_DEF(pj_status_t) pjmedia_silence_det_create( pj_pool_t *pool, + unsigned clock_rate, + unsigned samples_per_frame, + pjmedia_silence_det **p_sd) +{ + pjmedia_silence_det *sd; + + PJ_ASSERT_RETURN(pool && p_sd, PJ_EINVAL); + + sd = PJ_POOL_ZALLOC_T(pool, pjmedia_silence_det); + + pj_ansi_snprintf(sd->objname, PJ_MAX_OBJ_NAME, "sd%p", sd); + sd->objname[PJ_MAX_OBJ_NAME-1] = '\0'; + + sd->ptime = samples_per_frame * 1000 / clock_rate; + + /* Default settings */ + pjmedia_silence_det_set_params(sd, -1, -1, -1); + + /* Restart in adaptive, silent mode */ + pjmedia_silence_det_set_adaptive( sd, -1 ); + + *p_sd = sd; + return PJ_SUCCESS; +} + + +PJ_DEF(pj_status_t) pjmedia_silence_det_set_name( pjmedia_silence_det *sd, + const char *name) +{ + PJ_ASSERT_RETURN(sd && name, PJ_EINVAL); + + pj_ansi_snprintf(sd->objname, PJ_MAX_OBJ_NAME, name, sd); + sd->objname[PJ_MAX_OBJ_NAME-1] = '\0'; + return PJ_SUCCESS; +} + +PJ_DEF(pj_status_t) pjmedia_silence_det_set_adaptive(pjmedia_silence_det *sd, + int threshold) +{ + PJ_ASSERT_RETURN(sd, PJ_EINVAL); + + if (threshold < 0) + threshold = DEF_THRESHOLD; + + sd->mode = VAD_MODE_ADAPTIVE; + sd->threshold = threshold; + + return PJ_SUCCESS; +} + +PJ_DEF(pj_status_t) pjmedia_silence_det_set_fixed( pjmedia_silence_det *sd, + int threshold ) +{ + PJ_ASSERT_RETURN(sd, PJ_EINVAL); + + if (threshold < 0) + threshold = DEF_THRESHOLD; + + sd->mode = VAD_MODE_FIXED; + sd->threshold = threshold; + + return PJ_SUCCESS; +} + +PJ_DEF(pj_status_t) pjmedia_silence_det_set_params( pjmedia_silence_det *sd, + int before_silence, + int recalc_time1, + int recalc_time2) +{ + PJ_ASSERT_RETURN(sd, PJ_EINVAL); + + if (recalc_time1 < 0) + recalc_time1 = DEF_RECALC_ON_VOICED; + if (recalc_time2 < 0) + recalc_time2 = DEF_RECALC_ON_SILENCE; + if (before_silence < 0) + before_silence = DEF_BEFORE_SILENCE; + + sd->recalc_on_voiced = recalc_time1; + sd->recalc_on_silence = recalc_time2; + sd->before_silence = before_silence; + + return PJ_SUCCESS; +} + + +PJ_DEF(pj_status_t) pjmedia_silence_det_disable( pjmedia_silence_det *sd ) +{ + PJ_ASSERT_RETURN(sd, PJ_EINVAL); + + sd->mode = VAD_MODE_NONE; + + return PJ_SUCCESS; +} + + +PJ_DEF(pj_int32_t) pjmedia_calc_avg_signal( const pj_int16_t samples[], + pj_size_t count) +{ + pj_uint32_t sum = 0; + + const pj_int16_t * pcm = samples; + const pj_int16_t * end = samples + count; + + if (count==0) + return 0; + + while (pcm != end) { + if (*pcm < 0) + sum -= *pcm++; + else + sum += *pcm++; + } + + return (pj_int32_t)(sum / count); +} + +PJ_DEF(pj_bool_t) pjmedia_silence_det_apply( pjmedia_silence_det *sd, + pj_uint32_t level) +{ + int avg_recent_level; + + if (sd->mode == VAD_MODE_NONE) + return PJ_FALSE; + + if (sd->mode == VAD_MODE_FIXED) + return (level < sd->threshold); + + /* Calculating recent level */ + sd->sum_level += level; + ++sd->sum_cnt; + avg_recent_level = (sd->sum_level / sd->sum_cnt); + + if (level > sd->threshold || + level >= PJMEDIA_SILENCE_DET_MAX_THRESHOLD) + { + sd->silence_timer = 0; + sd->voiced_timer += sd->ptime; + + switch(sd->state) { + case STATE_VOICED: + if (sd->voiced_timer > sd->recalc_on_voiced) { + /* Voiced for long time (>recalc_on_voiced), current + * threshold seems to be too low. + */ + sd->threshold = (avg_recent_level + sd->threshold) >> 1; + TRACE_((THIS_FILE,"Re-adjust threshold (in talk burst)" + "to %d", sd->threshold)); + + sd->voiced_timer = 0; + + /* Reset sig_level */ + sd->sum_level = avg_recent_level; + sd->sum_cnt = 1; + } + break; + + case STATE_SILENCE: + TRACE_((THIS_FILE,"Starting talk burst (level=%d threshold=%d)", + level, sd->threshold)); + + case STATE_START_SILENCE: + sd->state = STATE_VOICED; + + /* Reset sig_level */ + sd->sum_level = level; + sd->sum_cnt = 1; + + break; + + default: + pj_assert(0); + break; + } + } else { + sd->voiced_timer = 0; + sd->silence_timer += sd->ptime; + + switch(sd->state) { + case STATE_SILENCE: + if (sd->silence_timer >= sd->recalc_on_silence) { + sd->threshold = avg_recent_level << 1; + TRACE_((THIS_FILE,"Re-adjust threshold (in silence)" + "to %d", sd->threshold)); + + sd->silence_timer = 0; + + /* Reset sig_level */ + sd->sum_level = avg_recent_level; + sd->sum_cnt = 1; + } + break; + + case STATE_VOICED: + sd->state = STATE_START_SILENCE; + + /* Reset sig_level */ + sd->sum_level = level; + sd->sum_cnt = 1; + + case STATE_START_SILENCE: + if (sd->silence_timer >= sd->before_silence) { + sd->state = STATE_SILENCE; + sd->threshold = avg_recent_level << 1; + TRACE_((THIS_FILE,"Starting silence (level=%d " + "threshold=%d)", level, sd->threshold)); + + /* Reset sig_level */ + sd->sum_level = avg_recent_level; + sd->sum_cnt = 1; + } + break; + + default: + pj_assert(0); + break; + } + } + + return (sd->state == STATE_SILENCE); +} + + +PJ_DEF(pj_bool_t) pjmedia_silence_det_detect( pjmedia_silence_det *sd, + const pj_int16_t samples[], + pj_size_t count, + pj_int32_t *p_level) +{ + pj_uint32_t level; + + /* Calculate average signal level. */ + level = pjmedia_calc_avg_signal(samples, count); + + /* Report to caller, if required. */ + if (p_level) + *p_level = level; + + return pjmedia_silence_det_apply(sd, level); +} + |