Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* $Id$ */ |
| 2 | /* |
| 3 | * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| 4 | * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | #ifndef __PJMEDIA_SILENCE_DET_H__ |
| 21 | #define __PJMEDIA_SILENCE_DET_H__ |
| 22 | |
| 23 | |
| 24 | /** |
| 25 | * @file silencedet.h |
| 26 | * @brief Adaptive silence detector. |
| 27 | */ |
| 28 | #include <pjmedia/types.h> |
| 29 | |
| 30 | |
| 31 | /** |
| 32 | * @defgroup PJMEDIA_SILENCEDET Adaptive Silence Detection |
| 33 | * @ingroup PJMEDIA_FRAME_OP |
| 34 | * @brief Adaptive Silence Detector |
| 35 | * @{ |
| 36 | */ |
| 37 | |
| 38 | |
| 39 | PJ_BEGIN_DECL |
| 40 | |
| 41 | |
| 42 | /** |
| 43 | * Opaque declaration for silence detector. |
| 44 | */ |
| 45 | typedef struct pjmedia_silence_det pjmedia_silence_det; |
| 46 | |
| 47 | |
| 48 | |
| 49 | /** |
| 50 | * Create voice activity detector with default settings. The default settings |
| 51 | * are set to adaptive silence detection with the default threshold. |
| 52 | * |
| 53 | * @param pool Pool for allocating the structure. |
| 54 | * @param clock_rate Clock rate. |
| 55 | * @param samples_per_frame Number of samples per frame. The clock_rate and |
| 56 | * samples_per_frame is only used to calculate the |
| 57 | * frame time, from which some timing parameters |
| 58 | * are calculated from. |
| 59 | * @param p_sd Pointer to receive the silence detector instance. |
| 60 | * |
| 61 | * @return PJ_SUCCESS on success. |
| 62 | */ |
| 63 | PJ_DECL(pj_status_t) pjmedia_silence_det_create( pj_pool_t *pool, |
| 64 | unsigned clock_rate, |
| 65 | unsigned samples_per_frame, |
| 66 | pjmedia_silence_det **p_sd ); |
| 67 | |
| 68 | |
| 69 | /** |
| 70 | * Set silence detector name to identify the particular silence detector |
| 71 | * instance in the log. |
| 72 | * |
| 73 | * @param sd The silence detector. |
| 74 | * @param name Name. |
| 75 | * |
| 76 | * @return PJ_SUCCESS on success. |
| 77 | */ |
| 78 | PJ_DECL(pj_status_t) pjmedia_silence_det_set_name(pjmedia_silence_det *sd, |
| 79 | const char *name); |
| 80 | |
| 81 | |
| 82 | /** |
| 83 | * Set the sd to operate in fixed threshold mode. With fixed threshold mode, |
| 84 | * the threshold will not be changed adaptively. |
| 85 | * |
| 86 | * @param sd The silence detector |
| 87 | * @param threshold The silence threshold, or -1 to use default |
| 88 | * threshold. |
| 89 | * |
| 90 | * @return PJ_SUCCESS on success. |
| 91 | */ |
| 92 | PJ_DECL(pj_status_t) pjmedia_silence_det_set_fixed( pjmedia_silence_det *sd, |
| 93 | int threshold ); |
| 94 | |
| 95 | /** |
| 96 | * Set the sd to operate in adaptive mode. This is the default mode |
| 97 | * when the silence detector is created. |
| 98 | * |
| 99 | * @param sd The silence detector |
| 100 | * @param threshold Initial threshold to be set, or -1 to use default |
| 101 | * threshold. |
| 102 | * |
| 103 | * @return PJ_SUCCESS on success. |
| 104 | */ |
| 105 | PJ_DECL(pj_status_t) pjmedia_silence_det_set_adaptive(pjmedia_silence_det *sd, |
| 106 | int threshold); |
| 107 | |
| 108 | /** |
| 109 | * Set other silence detector parameters. |
| 110 | * |
| 111 | * @param sd The silence detector |
| 112 | * @param before_silence Minimum duration of silence (in msec) before |
| 113 | * silence is reported. If -1 is specified, then |
| 114 | * the default value will be used. The default is |
| 115 | * 400 msec. |
| 116 | * @param recalc_time1 The interval (in msec) to recalculate threshold |
| 117 | * in non-silence condition when adaptive silence |
| 118 | * detection is set. If -1 is specified, then the |
| 119 | * default value will be used. The default is 4000 |
| 120 | * (msec). |
| 121 | * @param recalc_time2 The interval (in msec) to recalculate threshold |
| 122 | * in silence condition when adaptive silence detection |
| 123 | * is set. If -1 is specified, then the default value |
| 124 | * will be used. The default value is 2000 (msec). |
| 125 | * |
| 126 | * @return PJ_SUCCESS on success. |
| 127 | */ |
| 128 | PJ_DECL(pj_status_t) pjmedia_silence_det_set_params( pjmedia_silence_det *sd, |
| 129 | int before_silence, |
| 130 | int recalc_time1, |
| 131 | int recalc_time2); |
| 132 | |
| 133 | |
| 134 | /** |
| 135 | * Disable the silence detector. |
| 136 | * |
| 137 | * @param sd The silence detector |
| 138 | * |
| 139 | * @return PJ_SUCCESS on success. |
| 140 | */ |
| 141 | PJ_DECL(pj_status_t) pjmedia_silence_det_disable( pjmedia_silence_det *sd ); |
| 142 | |
| 143 | |
| 144 | /** |
| 145 | * Perform voice activity detection on the given input samples. This |
| 146 | * function uses #pjmedia_calc_avg_signal() and #pjmedia_silence_det_apply() |
| 147 | * for its calculation. |
| 148 | * |
| 149 | * @param sd The silence detector instance. |
| 150 | * @param samples Pointer to 16-bit PCM input samples. |
| 151 | * @param count Number of samples in the input. |
| 152 | * @param p_level Optional pointer to receive average signal level |
| 153 | * of the input samples. |
| 154 | * |
| 155 | * @return Non zero if signal is silence. |
| 156 | */ |
| 157 | PJ_DECL(pj_bool_t) pjmedia_silence_det_detect( pjmedia_silence_det *sd, |
| 158 | const pj_int16_t samples[], |
| 159 | pj_size_t count, |
| 160 | pj_int32_t *p_level); |
| 161 | |
| 162 | |
| 163 | /** |
| 164 | * Calculate average signal level for the given samples. |
| 165 | * |
| 166 | * @param samples Pointer to 16-bit PCM samples. |
| 167 | * @param count Number of samples in the input. |
| 168 | * |
| 169 | * @return The average signal level, which simply is total level |
| 170 | * divided by number of samples. |
| 171 | */ |
| 172 | PJ_DECL(pj_int32_t) pjmedia_calc_avg_signal( const pj_int16_t samples[], |
| 173 | pj_size_t count ); |
| 174 | |
| 175 | |
| 176 | |
| 177 | /** |
| 178 | * Perform voice activity detection, given the specified average signal |
| 179 | * level. |
| 180 | * |
| 181 | * @param sd The silence detector instance. |
| 182 | * @param level Signal level. |
| 183 | * |
| 184 | * @return Non zero if signal is silence. |
| 185 | */ |
| 186 | PJ_DECL(pj_bool_t) pjmedia_silence_det_apply( pjmedia_silence_det *sd, |
| 187 | pj_uint32_t level); |
| 188 | |
| 189 | |
| 190 | |
| 191 | PJ_END_DECL |
| 192 | |
| 193 | |
| 194 | /** |
| 195 | * @} |
| 196 | */ |
| 197 | |
| 198 | |
| 199 | #endif /* __PJMEDIA_SILENCE_DET_H__ */ |
| 200 | |