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_CLOCK_H__ |
| 21 | #define __PJMEDIA_CLOCK_H__ |
| 22 | |
| 23 | /** |
| 24 | * @file clock.h |
| 25 | * @brief Media clock. |
| 26 | */ |
| 27 | #include <pjmedia/types.h> |
| 28 | |
| 29 | |
| 30 | /** |
| 31 | * @defgroup PJMEDIA_PORT_CLOCK Clock/Timing |
| 32 | * @ingroup PJMEDIA_PORT |
| 33 | * @brief Various types of classes that provide timing. |
| 34 | * @{ |
| 35 | |
| 36 | The media clock/timing extends the media port concept that is explained |
| 37 | in @ref PJMEDIA_PORT. When clock is present in the ports |
| 38 | interconnection, media will flow automatically (and with correct timing too!) |
| 39 | from one media port to another. |
| 40 | |
| 41 | There are few objects in PJMEDIA that are able to provide clock/timing |
| 42 | to media ports interconnection: |
| 43 | |
| 44 | - @ref PJMED_SND_PORT\n |
| 45 | The sound device makes a good candidate as the clock source, and |
| 46 | PJMEDIA @ref PJMED_SND is designed so that it is able to invoke |
| 47 | operations according to timing driven by the sound hardware clock |
| 48 | (this may sound complicated, but actually it just means that |
| 49 | the sound device abstraction provides callbacks to be called when |
| 50 | it has/wants media frames).\n |
| 51 | See @ref PJMED_SND_PORT for more details. |
| 52 | |
| 53 | - @ref PJMEDIA_MASTER_PORT\n |
| 54 | The master port uses @ref PJMEDIA_CLOCK as the clock source. By using |
| 55 | @ref PJMEDIA_MASTER_PORT, it is possible to interconnect passive |
| 56 | media ports and let the frames flow automatically in timely manner.\n |
| 57 | Please see @ref PJMEDIA_MASTER_PORT for more details. |
| 58 | |
| 59 | @} |
| 60 | */ |
| 61 | |
| 62 | |
| 63 | /** |
| 64 | * @addtogroup PJMEDIA_CLOCK Clock Generator |
| 65 | * @ingroup PJMEDIA_PORT_CLOCK |
| 66 | * @brief Interface for generating clock. |
| 67 | * @{ |
| 68 | * |
| 69 | * The clock generator provides the application with media timing, |
| 70 | * and it is used by the @ref PJMEDIA_MASTER_PORT for its sound clock. |
| 71 | * |
| 72 | * The clock generator may be configured to run <b>asynchronously</b> |
| 73 | * (the default behavior) or <b>synchronously</b>. When it is run |
| 74 | * asynchronously, it will call the application's callback every time |
| 75 | * the clock <b>tick</b> expires. When it is run synchronously, |
| 76 | * application must continuously polls the clock generator to synchronize |
| 77 | * the timing. |
| 78 | */ |
| 79 | |
| 80 | PJ_BEGIN_DECL |
| 81 | |
| 82 | /** |
| 83 | * Media clock source. |
| 84 | */ |
| 85 | typedef struct pjmedia_clock_src |
| 86 | { |
| 87 | pjmedia_type media_type; /**< Media type. */ |
| 88 | unsigned clock_rate; /**< Clock rate. */ |
| 89 | unsigned ptime_usec; /**< Frame interval (in usec). */ |
| 90 | /** |
| 91 | * The timestamp field holds an increasing value in samples and its |
| 92 | * value is expected to be increased by clock_rate samples per second. |
| 93 | */ |
| 94 | pj_timestamp timestamp; |
| 95 | /** |
| 96 | * Timestamp's last update. The last_update field contains a value in |
| 97 | * ticks, and it is expected to be increased by pj_get_timestamp_freq() |
| 98 | * ticks per second. |
| 99 | */ |
| 100 | pj_timestamp last_update; |
| 101 | } pjmedia_clock_src; |
| 102 | |
| 103 | /** |
| 104 | * This is an auxiliary function to initialize the media clock source. |
| 105 | * |
| 106 | * @param clocksrc The clock source to be initialized. |
| 107 | * @param media_type The media type. |
| 108 | * @param clock_rate The clock rate. |
| 109 | * @param ptime_usec Media frame interval (in usec). |
| 110 | * |
| 111 | * @return PJ_SUCCESS on success. |
| 112 | */ |
| 113 | PJ_DECL(pj_status_t) pjmedia_clock_src_init( pjmedia_clock_src *clocksrc, |
| 114 | pjmedia_type media_type, |
| 115 | unsigned clock_rate, |
| 116 | unsigned ptime_usec ); |
| 117 | |
| 118 | /** |
| 119 | * This function updates the clock source's timestamp. Application should |
| 120 | * use this function instead of updating the timestamp directly since this |
| 121 | * function will also update the last_update field of the clock source. |
| 122 | * |
| 123 | * @param clocksrc The clock source to be updated. |
| 124 | * @param timestamp The new timestamp, can be NULL if the current |
| 125 | * timestamp does not change (in this case it |
| 126 | * will only update the last_update field). |
| 127 | * |
| 128 | * @return PJ_SUCCESS on success. |
| 129 | */ |
| 130 | PJ_DECL(pj_status_t) pjmedia_clock_src_update( pjmedia_clock_src *clocksrc, |
| 131 | const pj_timestamp *timestamp ); |
| 132 | |
| 133 | /** |
| 134 | * This function gets the clock source's current timestamp. Application |
| 135 | * should use this function instead of accessing the timestamp directly |
| 136 | * since this function will calculate the predicted timestamp for current |
| 137 | * time, based on the values of timestamp, last_update, and clock_rate. |
| 138 | * |
| 139 | * @param clocksrc The clock source. |
| 140 | * @param timestamp Argument to receive the current timestamp |
| 141 | * |
| 142 | * @return PJ_SUCCESS on success. |
| 143 | */ |
| 144 | PJ_DECL(pj_status_t) |
| 145 | pjmedia_clock_src_get_current_timestamp( const pjmedia_clock_src *clocksrc, |
| 146 | pj_timestamp *timestamp); |
| 147 | |
| 148 | /** |
| 149 | * This function gets the clock source's time in msec. |
| 150 | * |
| 151 | * @param clocksrc The clock source. |
| 152 | * |
| 153 | * @return The clock source's time (in msec). |
| 154 | */ |
| 155 | PJ_DECL(pj_uint32_t) |
| 156 | pjmedia_clock_src_get_time_msec( const pjmedia_clock_src *clocksrc ); |
| 157 | |
| 158 | |
| 159 | /** |
| 160 | * Opaque declaration for media clock. |
| 161 | */ |
| 162 | typedef struct pjmedia_clock pjmedia_clock; |
| 163 | |
| 164 | |
| 165 | /** |
| 166 | * Options when creating the clock. |
| 167 | */ |
| 168 | enum pjmedia_clock_options |
| 169 | { |
| 170 | /** |
| 171 | * Prevents the clock from running asynchronously. In this case, |
| 172 | * application must poll the clock continuously by calling |
| 173 | * #pjmedia_clock_wait() in order to synchronize timing. |
| 174 | */ |
| 175 | PJMEDIA_CLOCK_NO_ASYNC = 1, |
| 176 | |
| 177 | /** |
| 178 | * Prevent the clock from setting it's thread to highest priority. |
| 179 | */ |
| 180 | PJMEDIA_CLOCK_NO_HIGHEST_PRIO = 2 |
| 181 | }; |
| 182 | |
| 183 | |
| 184 | typedef struct pjmedia_clock_param |
| 185 | { |
| 186 | /** |
| 187 | * The frame interval, in microseconds. |
| 188 | */ |
| 189 | unsigned usec_interval; |
| 190 | /** |
| 191 | * The media clock rate, to determine timestamp |
| 192 | * increment for each call. |
| 193 | */ |
| 194 | unsigned clock_rate; |
| 195 | } pjmedia_clock_param; |
| 196 | |
| 197 | /** |
| 198 | * Type of media clock callback. |
| 199 | * |
| 200 | * @param ts Current timestamp, in samples. |
| 201 | * @param user_data Application data that is passed when |
| 202 | * the clock was created. |
| 203 | */ |
| 204 | typedef void pjmedia_clock_callback(const pj_timestamp *ts, |
| 205 | void *user_data); |
| 206 | |
| 207 | |
| 208 | |
| 209 | /** |
| 210 | * Create media clock. This creates a media clock object that will run |
| 211 | * periodically at an interval that is calculated from the audio parameters. |
| 212 | * Once created, application must call #pjmedia_clock_start() to actually |
| 213 | * start the clock. |
| 214 | * |
| 215 | * @see pjmedia_clock_create2() |
| 216 | * |
| 217 | * @param pool Pool to allocate memory. |
| 218 | * @param clock_rate Number of samples per second. |
| 219 | * @param channel_count Number of channel. |
| 220 | * @param samples_per_frame Number of samples per frame. This argument |
| 221 | * along with clock_rate and channel_count, specifies |
| 222 | * the interval of each clock run (or clock ticks). |
| 223 | * @param options Bitmask of pjmedia_clock_options. |
| 224 | * @param cb Callback to be called for each clock tick. |
| 225 | * @param user_data User data, which will be passed to the callback. |
| 226 | * @param p_clock Pointer to receive the clock instance. |
| 227 | * |
| 228 | * @return PJ_SUCCESS on success, or the appropriate error |
| 229 | * code. |
| 230 | */ |
| 231 | PJ_DECL(pj_status_t) pjmedia_clock_create( pj_pool_t *pool, |
| 232 | unsigned clock_rate, |
| 233 | unsigned channel_count, |
| 234 | unsigned samples_per_frame, |
| 235 | unsigned options, |
| 236 | pjmedia_clock_callback *cb, |
| 237 | void *user_data, |
| 238 | pjmedia_clock **p_clock); |
| 239 | |
| 240 | |
| 241 | /** |
| 242 | * Create media clock. This creates a media clock object that will run |
| 243 | * periodically at the specified interval. Once created, application must |
| 244 | * call #pjmedia_clock_start() to actually start the clock. |
| 245 | * |
| 246 | * @param pool Pool to allocate memory. |
| 247 | * @param param The clock parameter. |
| 248 | * @param options Bitmask of pjmedia_clock_options. |
| 249 | * @param cb Callback to be called for each clock tick. |
| 250 | * @param user_data User data, which will be passed to the callback. |
| 251 | * @param p_clock Pointer to receive the clock instance. |
| 252 | * |
| 253 | * @return PJ_SUCCESS on success, or the appropriate error |
| 254 | * code. |
| 255 | */ |
| 256 | PJ_DECL(pj_status_t) pjmedia_clock_create2(pj_pool_t *pool, |
| 257 | const pjmedia_clock_param *param, |
| 258 | unsigned options, |
| 259 | pjmedia_clock_callback *cb, |
| 260 | void *user_data, |
| 261 | pjmedia_clock **p_clock); |
| 262 | |
| 263 | /** |
| 264 | * Start the clock. For clock created with asynchronous flag set to TRUE, |
| 265 | * this may start a worker thread for the clock (depending on the |
| 266 | * backend clock implementation being used). |
| 267 | * |
| 268 | * @param clock The media clock. |
| 269 | * |
| 270 | * @return PJ_SUCCES on success. |
| 271 | */ |
| 272 | PJ_DECL(pj_status_t) pjmedia_clock_start(pjmedia_clock *clock); |
| 273 | |
| 274 | |
| 275 | /** |
| 276 | * Stop the clock. |
| 277 | * |
| 278 | * @param clock The media clock. |
| 279 | * |
| 280 | * @return PJ_SUCCES on success. |
| 281 | */ |
| 282 | PJ_DECL(pj_status_t) pjmedia_clock_stop(pjmedia_clock *clock); |
| 283 | |
| 284 | |
| 285 | /** |
| 286 | * Modify the clock's parameter. |
| 287 | * |
| 288 | * @param clock The media clock. |
| 289 | * @param param The clock's new parameter. |
| 290 | * @return PJ_SUCCES on success. |
| 291 | */ |
| 292 | PJ_DECL(pj_status_t) pjmedia_clock_modify(pjmedia_clock *clock, |
| 293 | const pjmedia_clock_param *param); |
| 294 | |
| 295 | |
| 296 | /** |
| 297 | * Poll the media clock, and execute the callback when the clock tick has |
| 298 | * elapsed. This operation is only valid if the clock is created with async |
| 299 | * flag set to FALSE. |
| 300 | * |
| 301 | * @param clock The media clock. |
| 302 | * @param wait If non-zero, then the function will block until |
| 303 | * a clock tick elapsed and callback has been called. |
| 304 | * @param ts Optional argument to receive the current |
| 305 | * timestamp. |
| 306 | * |
| 307 | * @return Non-zero if clock tick has elapsed, or FALSE if |
| 308 | * the function returns before a clock tick has |
| 309 | * elapsed. |
| 310 | */ |
| 311 | PJ_DECL(pj_bool_t) pjmedia_clock_wait(pjmedia_clock *clock, |
| 312 | pj_bool_t wait, |
| 313 | pj_timestamp *ts); |
| 314 | |
| 315 | |
| 316 | /** |
| 317 | * Destroy the clock. |
| 318 | * |
| 319 | * @param clock The media clock. |
| 320 | * |
| 321 | * @return PJ_SUCCES on success. |
| 322 | */ |
| 323 | PJ_DECL(pj_status_t) pjmedia_clock_destroy(pjmedia_clock *clock); |
| 324 | |
| 325 | |
| 326 | |
| 327 | PJ_END_DECL |
| 328 | |
| 329 | /** |
| 330 | * @} |
| 331 | */ |
| 332 | |
| 333 | |
| 334 | #endif /* __PJMEDIA_CLOCK_H__ */ |
| 335 | |