Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [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_CODECS_PASSTHROUGH_H__ |
| 21 | #define __PJMEDIA_CODECS_PASSTHROUGH_H__ |
| 22 | |
| 23 | /** |
| 24 | * @file pjmedia-codec/passthrough.h |
| 25 | * @brief Passthrough codecs. |
| 26 | */ |
| 27 | |
| 28 | #include <pjmedia-codec/types.h> |
| 29 | |
| 30 | /** |
| 31 | * @defgroup PJMED_PASSTHROUGH_CODEC Passthrough Codecs |
| 32 | * @ingroup PJMEDIA_CODEC_CODECS |
| 33 | * @brief Implementation of passthrough codecs |
| 34 | * @{ |
| 35 | * |
| 36 | * This section describes functions to initialize and register passthrough |
| 37 | * codecs factory to the codec manager. After the codec factory has been |
| 38 | * registered, application can use @ref PJMEDIA_CODEC API to manipulate |
| 39 | * the codec. |
| 40 | * |
| 41 | * Passthrough codecs are codecs wrapper that does NOT perform encoding |
| 42 | * or decoding, it just PACK and PARSE encoded audio data from/into RTP |
| 43 | * payload. This will accomodate pjmedia ports which work with encoded |
| 44 | * audio data, e.g: encoded audio files, sound device with capability |
| 45 | * of playing/recording encoded audio data. |
| 46 | * |
| 47 | * This codec factory contains various codecs, i.e: G.729, iLBC, |
| 48 | * AMR, and G.711. |
| 49 | * |
| 50 | * |
| 51 | * \section pjmedia_codec_passthrough_g729 Passthrough G.729 |
| 52 | * |
| 53 | * G.729 supports 16-bit PCM audio signal with sampling rate 8000Hz, |
| 54 | * frame length 10ms, and resulting in bitrate 8000bps. |
| 55 | * |
| 56 | * \subsection codec_setting Codec Settings |
| 57 | * |
| 58 | * General codec settings for this codec such as VAD and PLC can be |
| 59 | * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. |
| 60 | * Please see the documentation of #pjmedia_codec_param for more info. |
| 61 | * |
| 62 | * Note that G.729 VAD status should be signalled in SDP, see more |
| 63 | * description below. |
| 64 | * |
| 65 | * \subsubsection annexb Annex B |
| 66 | * |
| 67 | * The capability of VAD/DTX is specified in Annex B. |
| 68 | * |
| 69 | * By default, Annex B is enabled. This default setting of Annex B can |
| 70 | * be modified using #pjmedia_codec_mgr_set_default_param(). |
| 71 | * |
| 72 | * In #pjmedia_codec_param, Annex B is configured via VAD setting and |
| 73 | * format parameter "annexb" in the SDP "a=fmtp" attribute in |
| 74 | * decoding fmtp field. Valid values are "yes" and "no", |
| 75 | * the implementation default is "yes". When this parameter is omitted |
| 76 | * in the SDP, the value will be "yes" (RFC 4856 Section 2.1.9). |
| 77 | * |
| 78 | * Here is an example of modifying default setting of Annex B to |
| 79 | * be disabled using #pjmedia_codec_mgr_set_default_param(): |
| 80 | \code |
| 81 | pjmedia_codec_param param; |
| 82 | |
| 83 | pjmedia_codec_mgr_get_default_param(.., ¶m); |
| 84 | ... |
| 85 | // Set VAD |
| 86 | param.setting.vad = 0; |
| 87 | // Set SDP format parameter |
| 88 | param.setting.dec_fmtp.cnt = 1; |
| 89 | param.setting.dec_fmtp.param[0].name = pj_str("annexb"); |
| 90 | param.setting.dec_fmtp.param[0].val = pj_str("no"); |
| 91 | ... |
| 92 | pjmedia_codec_mgr_set_default_param(.., ¶m); |
| 93 | \endcode |
| 94 | * |
| 95 | * \note |
| 96 | * The difference of Annex B status in SDP offer/answer may be considered as |
| 97 | * incompatible codec in SDP negotiation. |
| 98 | * |
| 99 | * |
| 100 | * \section pjmedia_codec_passthrough_ilbc Passthrough iLBC |
| 101 | * |
| 102 | * The iLBC codec is developed by Global IP Solutions (GIPS), formerly |
| 103 | * Global IP Sound. The iLBC offers low bitrate and graceful audio quality |
| 104 | * degradation on frame losses. |
| 105 | * |
| 106 | * The iLBC codec supports 16-bit PCM audio signal with sampling rate of |
| 107 | * 8000Hz operating at two modes: 20ms and 30ms frame length modes, resulting |
| 108 | * in bitrates of 15.2kbps for 20ms mode and 13.33kbps for 30ms mode. |
| 109 | * |
| 110 | * \subsection codec_setting Codec Settings |
| 111 | * |
| 112 | * General codec settings for this codec such as VAD and PLC can be |
| 113 | * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. |
| 114 | * Please see the documentation of #pjmedia_codec_param for more info. |
| 115 | * |
| 116 | * \subsubsection mode Mode |
| 117 | * |
| 118 | * The default mode should be set upon initialization, see |
| 119 | * #pjmedia_codec_passthrough_init2(). After the codec is initialized, the |
| 120 | * default mode can be modified using #pjmedia_codec_mgr_set_default_param(). |
| 121 | * |
| 122 | * In #pjmedia_codec_param, iLBC mode can be set by specifying SDP |
| 123 | * format parameter "mode" in the SDP "a=fmtp" attribute for decoding |
| 124 | * direction. Valid values are "20" and "30" (for 20ms and 30ms mode |
| 125 | * respectively). |
| 126 | * |
| 127 | * Here is an example to set up #pjmedia_codec_param to use mode 20ms: |
| 128 | * \code |
| 129 | pjmedia_codec_param param; |
| 130 | ... |
| 131 | // setting iLBC mode in SDP |
| 132 | param.setting.dec_fmtp.cnt = 1; |
| 133 | param.setting.dec_fmtp.param[0].name = pj_str("mode"); |
| 134 | param.setting.dec_fmtp.param[0].val = pj_str("20"); |
| 135 | ... |
| 136 | \endcode |
| 137 | * |
| 138 | * |
| 139 | * \section pjmedia_codec_passthrough_amr Passthrough AMR |
| 140 | * |
| 141 | * IPP AMR supports 16-bit PCM audio signal with sampling rate 8000Hz, |
| 142 | * 20ms frame length and producing various bitrates that ranges from 4.75kbps |
| 143 | * to 12.2kbps. |
| 144 | * |
| 145 | * \subsection codec_setting Codec Settings |
| 146 | * |
| 147 | * General codec settings for this codec such as VAD and PLC can be |
| 148 | * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. |
| 149 | * Please see the documentation of #pjmedia_codec_param for more info. |
| 150 | * |
| 151 | * \subsubsection bitrate Bitrate |
| 152 | * |
| 153 | * By default, encoding bitrate is 7400bps. This default setting can be |
| 154 | * modified using #pjmedia_codec_mgr_set_default_param() by specifying |
| 155 | * prefered AMR bitrate in field <tt>info::avg_bps</tt> of |
| 156 | * #pjmedia_codec_param. Valid bitrates could be seen in |
| 157 | * #pjmedia_codec_amrnb_bitrates. |
| 158 | * |
| 159 | * \subsubsection payload_format Payload Format |
| 160 | * |
| 161 | * There are two AMR payload format types, bandwidth-efficient and |
| 162 | * octet-aligned. Default setting is using octet-aligned. This default payload |
| 163 | * format can be modified using #pjmedia_codec_mgr_set_default_param(). |
| 164 | * |
| 165 | * In #pjmedia_codec_param, payload format can be set by specifying SDP |
| 166 | * format parameters "octet-align" in the SDP "a=fmtp" attribute for |
| 167 | * decoding direction. Valid values are "0" (for bandwidth efficient mode) |
| 168 | * and "1" (for octet-aligned mode). |
| 169 | * |
| 170 | * \subsubsection mode_set Mode-Set |
| 171 | * |
| 172 | * Mode-set is used for restricting AMR modes in decoding direction. |
| 173 | * |
| 174 | * By default, no mode-set restriction applied. This default setting can be |
| 175 | * be modified using #pjmedia_codec_mgr_set_default_param(). |
| 176 | * |
| 177 | * In #pjmedia_codec_param, mode-set could be specified via format parameters |
| 178 | * "mode-set" in the SDP "a=fmtp" attribute for decoding direction. Valid |
| 179 | * value is a comma separated list of modes from the set 0 - 7, e.g: |
| 180 | * "4,5,6,7". When this parameter is omitted, no mode-set restrictions applied. |
| 181 | * |
| 182 | * Here is an example of modifying AMR default codec param: |
| 183 | \code |
| 184 | pjmedia_codec_param param; |
| 185 | |
| 186 | pjmedia_codec_mgr_get_default_param(.., ¶m); |
| 187 | ... |
| 188 | // set default encoding bitrate to the highest 12.2kbps |
| 189 | param.info.avg_bps = 12200; |
| 190 | |
| 191 | // restrict decoding bitrate to 10.2kbps and 12.2kbps only |
| 192 | param.setting.dec_fmtp.param[0].name = pj_str("mode-set"); |
| 193 | param.setting.dec_fmtp.param[0].val = pj_str("6,7"); |
| 194 | |
| 195 | // also set to use bandwidth-efficient payload format |
| 196 | param.setting.dec_fmtp.param[1].name = pj_str("octet-align"); |
| 197 | param.setting.dec_fmtp.param[1].val = pj_str("0"); |
| 198 | |
| 199 | param.setting.dec_fmtp.cnt = 2; |
| 200 | ... |
| 201 | pjmedia_codec_mgr_set_default_param(.., ¶m); |
| 202 | \endcode |
| 203 | * |
| 204 | * |
| 205 | * \section pjmedia_codec_passthrough_g711 Passthrough G.711 |
| 206 | * |
| 207 | * The G.711 is an ultra low complexity codecs and in trade-off it results |
| 208 | * in high bitrate, i.e: 64kbps for 16-bit PCM with sampling rate 8000Hz. |
| 209 | * |
| 210 | * The factory contains two main compression algorithms, PCMU/u-Law and |
| 211 | * PCMA/A-Law. |
| 212 | * |
| 213 | * \subsection codec_setting Codec Settings |
| 214 | * |
| 215 | * General codec settings for this codec such as VAD and PLC can be |
| 216 | * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. |
| 217 | * Please see the documentation of #pjmedia_codec_param for more info. |
| 218 | */ |
| 219 | |
| 220 | PJ_BEGIN_DECL |
| 221 | |
| 222 | |
| 223 | /** |
| 224 | * Codec passthrough configuration settings. |
| 225 | */ |
| 226 | typedef struct pjmedia_codec_passthrough_setting |
| 227 | { |
| 228 | unsigned fmt_cnt; /**< Number of encoding formats |
| 229 | to be enabled. */ |
| 230 | pjmedia_format *fmts; /**< Encoding formats to be |
| 231 | enabled. */ |
| 232 | unsigned ilbc_mode; /**< iLBC default mode. */ |
| 233 | } pjmedia_codec_passthrough_setting; |
| 234 | |
| 235 | |
| 236 | /** |
| 237 | * Initialize and register passthrough codecs factory to pjmedia endpoint, |
| 238 | * all supported encoding formats will be enabled. |
| 239 | * |
| 240 | * @param endpt The pjmedia endpoint. |
| 241 | * |
| 242 | * @return PJ_SUCCESS on success. |
| 243 | */ |
| 244 | PJ_DECL(pj_status_t) pjmedia_codec_passthrough_init( pjmedia_endpt *endpt ); |
| 245 | |
| 246 | |
| 247 | /** |
| 248 | * Initialize and register passthrough codecs factory to pjmedia endpoint |
| 249 | * with only specified encoding formats enabled. |
| 250 | * |
| 251 | * @param endpt The pjmedia endpoint. |
| 252 | * @param setting The settings. |
| 253 | * |
| 254 | * @return PJ_SUCCESS on success. |
| 255 | */ |
| 256 | PJ_DECL(pj_status_t) pjmedia_codec_passthrough_init2( |
| 257 | pjmedia_endpt *endpt, |
| 258 | const pjmedia_codec_passthrough_setting *setting); |
| 259 | |
| 260 | |
| 261 | /** |
| 262 | * Unregister passthrough codecs factory from pjmedia endpoint. |
| 263 | * |
| 264 | * @return PJ_SUCCESS on success. |
| 265 | */ |
| 266 | PJ_DECL(pj_status_t) pjmedia_codec_passthrough_deinit(void); |
| 267 | |
| 268 | |
| 269 | PJ_END_DECL |
| 270 | |
| 271 | |
| 272 | /** |
| 273 | * @} |
| 274 | */ |
| 275 | |
| 276 | #endif /* __PJMEDIA_CODECS_PASSTHROUGH_H__ */ |
| 277 | |