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_PORT_H__ |
| 21 | #define __PJMEDIA_PORT_H__ |
| 22 | |
| 23 | /** |
| 24 | * @file port.h |
| 25 | * @brief Port interface declaration |
| 26 | */ |
| 27 | #include <pjmedia/clock.h> |
| 28 | #include <pjmedia/event.h> |
| 29 | #include <pjmedia/format.h> |
| 30 | #include <pjmedia/frame.h> |
| 31 | #include <pjmedia/signatures.h> |
| 32 | #include <pj/assert.h> |
| 33 | #include <pj/os.h> |
| 34 | |
| 35 | |
| 36 | /** |
| 37 | @addtogroup PJMEDIA_PORT Media Ports Framework |
| 38 | @{ |
| 39 | |
| 40 | @section media_port_intro Media Port Concepts |
| 41 | |
| 42 | @subsection The Media Port |
| 43 | A media port (represented with pjmedia_port "class") provides a generic |
| 44 | and extensible framework for implementing media elements. Media element |
| 45 | itself could be a media source, sink, or processing element. A media |
| 46 | port interface basically has the following properties: |
| 47 | - media port information (pjmedia_port_info) to describe the |
| 48 | media port properties (sampling rate, number of channels, etc.), |
| 49 | - optional pointer to function to acquire frames from the port (the |
| 50 | <tt>get_frame() </tt> interface), which will be called by |
| 51 | #pjmedia_port_get_frame() public API, and |
| 52 | - optional pointer to function to store frames to the port (the |
| 53 | <tt>put_frame()</tt> interface) which will be called by |
| 54 | #pjmedia_port_put_frame() public API. |
| 55 | |
| 56 | The <tt>get_frame()</tt> and <tt>put_frame()</tt> interface of course |
| 57 | would only need to be implemented if the media port emits and/or takes |
| 58 | media frames respectively. |
| 59 | |
| 60 | Media ports are passive "objects". By default, there is no worker thread |
| 61 | to run the media flow. Applications (or other PJMEDIA |
| 62 | components, as explained in @ref PJMEDIA_PORT_CLOCK) must actively call |
| 63 | #pjmedia_port_get_frame() or #pjmedia_port_put_frame() from/to the media |
| 64 | port in order to retrieve/store media frames. |
| 65 | |
| 66 | Some media ports (such as @ref PJMEDIA_CONF and @ref PJMEDIA_RESAMPLE_PORT) |
| 67 | may be interconnected with (or encapsulate) other port, to perform the |
| 68 | combined task of the ports, while some |
| 69 | others represent the ultimate source/sink termination for the media. |
| 70 | Interconnection means the upstream media port will call <tt>get_frame()</tt> |
| 71 | and <tt>put_frame()</tt> to its downstream media port. For this to happen, |
| 72 | the media ports need to have the same format, where format is defined as |
| 73 | combination of sample format, clock rate, channel count, bits per sample, |
| 74 | and samples per frame for audio media. |
| 75 | |
| 76 | |
| 77 | @subsection port_clock_ex1 Example: Manual Resampling |
| 78 | |
| 79 | For example, suppose application wants to convert the sampling rate |
| 80 | of one WAV file to another. In this case, application would create and |
| 81 | arrange media ports connection as follows: |
| 82 | |
| 83 | \image html sample-manual-resampling.jpg |
| 84 | |
| 85 | Application would setup the media ports using the following pseudo- |
| 86 | code: |
| 87 | |
| 88 | \code |
| 89 | |
| 90 | pjmedia_port *player, *resample, *writer; |
| 91 | pj_status_t status; |
| 92 | |
| 93 | // Create the file player port. |
| 94 | status = pjmedia_wav_player_port_create(pool, |
| 95 | "Input.WAV", // file name |
| 96 | 20, // ptime. |
| 97 | PJMEDIA_FILE_NO_LOOP, // flags |
| 98 | 0, // buffer size |
| 99 | NULL, // user data. |
| 100 | &player ); |
| 101 | PJ_ASSERT_RETURN(status==PJ_SUCCESS, PJ_SUCCESS); |
| 102 | |
| 103 | // Create the resample port with specifying the target sampling rate, |
| 104 | // and with the file port as the source. This will effectively |
| 105 | // connect the resample port with the player port. |
| 106 | status = pjmedia_resample_port_create( pool, player, 8000, |
| 107 | 0, &resample); |
| 108 | PJ_ASSERT_RETURN(status==PJ_SUCCESS, PJ_SUCCESS); |
| 109 | |
| 110 | // Create the file writer, specifying the resample port's configuration |
| 111 | // as the WAV parameters. |
| 112 | status pjmedia_wav_writer_port_create(pool, |
| 113 | "Output.WAV", // file name. |
| 114 | resample->info.clock_rate, |
| 115 | resample->info.channel_count, |
| 116 | resample->info.samples_per_frame, |
| 117 | resample->info.bits_per_sample, |
| 118 | 0, // flags |
| 119 | 0, // buffer size |
| 120 | NULL, // user data. |
| 121 | &writer); |
| 122 | |
| 123 | \endcode |
| 124 | |
| 125 | |
| 126 | After the ports have been set up, application can perform the conversion |
| 127 | process by running this loop: |
| 128 | |
| 129 | \code |
| 130 | |
| 131 | pj_int16_t samplebuf[MAX_FRAME]; |
| 132 | |
| 133 | while (1) { |
| 134 | pjmedia_frame frame; |
| 135 | pj_status_t status; |
| 136 | |
| 137 | frame.buf = samplebuf; |
| 138 | frame.size = sizeof(samplebuf); |
| 139 | |
| 140 | // Get the frame from resample port. |
| 141 | status = pjmedia_port_get_frame(resample, &frame); |
| 142 | if (status != PJ_SUCCESS || frame.type == PJMEDIA_FRAME_TYPE_NONE) { |
| 143 | // End-of-file, end the conversion. |
| 144 | break; |
| 145 | } |
| 146 | |
| 147 | // Put the frame to write port. |
| 148 | status = pjmedia_port_put_frame(writer, &frame); |
| 149 | if (status != PJ_SUCCESS) { |
| 150 | // Error in writing the file. |
| 151 | break; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | \endcode |
| 156 | |
| 157 | For the sake of completeness, after the resampling process is done, |
| 158 | application would need to destroy the ports: |
| 159 | |
| 160 | \code |
| 161 | // Note: by default, destroying resample port will destroy the |
| 162 | // the downstream port too. |
| 163 | pjmedia_port_destroy(resample); |
| 164 | pjmedia_port_destroy(writer); |
| 165 | \endcode |
| 166 | |
| 167 | |
| 168 | The above steps are okay for our simple purpose of changing file's sampling |
| 169 | rate. But for other purposes, the process of reading and writing frames |
| 170 | need to be done in timely manner (for example, sending RTP packets to |
| 171 | remote stream). And more over, as the application's scope goes bigger, |
| 172 | the same pattern of manually reading/writing frames comes up more and more often, |
| 173 | thus perhaps it would be better if PJMEDIA provides mechanism to |
| 174 | automate this process. |
| 175 | |
| 176 | And indeed PJMEDIA does provide such mechanism, which is described in |
| 177 | @ref PJMEDIA_PORT_CLOCK section. |
| 178 | |
| 179 | |
| 180 | @subsection media_port_autom Automating Media Flow |
| 181 | |
| 182 | PJMEDIA provides few mechanisms to make media flows automatically |
| 183 | among media ports. This concept is described in @ref PJMEDIA_PORT_CLOCK |
| 184 | section. |
| 185 | */ |
| 186 | |
| 187 | PJ_BEGIN_DECL |
| 188 | |
| 189 | |
| 190 | /** |
| 191 | * Create 32bit port signature from ASCII characters. |
| 192 | */ |
| 193 | #define PJMEDIA_PORT_SIG(a,b,c,d) PJMEDIA_OBJ_SIG(a,b,c,d) |
| 194 | |
| 195 | |
| 196 | /** |
| 197 | * Port operation setting. |
| 198 | */ |
| 199 | typedef enum pjmedia_port_op |
| 200 | { |
| 201 | /** |
| 202 | * No change to the port TX or RX settings. |
| 203 | */ |
| 204 | PJMEDIA_PORT_NO_CHANGE, |
| 205 | |
| 206 | /** |
| 207 | * TX or RX is disabled from the port. It means get_frame() or |
| 208 | * put_frame() WILL NOT be called for this port. |
| 209 | */ |
| 210 | PJMEDIA_PORT_DISABLE, |
| 211 | |
| 212 | /** |
| 213 | * TX or RX is muted, which means that get_frame() or put_frame() |
| 214 | * will still be called, but the audio frame is discarded. |
| 215 | */ |
| 216 | PJMEDIA_PORT_MUTE, |
| 217 | |
| 218 | /** |
| 219 | * Enable TX and RX to/from this port. |
| 220 | */ |
| 221 | PJMEDIA_PORT_ENABLE |
| 222 | |
| 223 | } pjmedia_port_op; |
| 224 | |
| 225 | |
| 226 | /** |
| 227 | * Port info. |
| 228 | */ |
| 229 | typedef struct pjmedia_port_info |
| 230 | { |
| 231 | pj_str_t name; /**< Port name. */ |
| 232 | pj_uint32_t signature; /**< Port signature. */ |
| 233 | pjmedia_dir dir; /**< Port direction. */ |
| 234 | pjmedia_format fmt; /**< Format. */ |
| 235 | } pjmedia_port_info; |
| 236 | |
| 237 | /** |
| 238 | * Utility to retrieve audio clock rate/sampling rate value from |
| 239 | * pjmedia_port_info. |
| 240 | * |
| 241 | * @param pia Pointer to port info containing audio format. |
| 242 | * @return Audio clock rate. |
| 243 | */ |
| 244 | PJ_INLINE(unsigned) PJMEDIA_PIA_SRATE(const pjmedia_port_info *pia) |
| 245 | { |
| 246 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 247 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 248 | return pia->fmt.det.aud.clock_rate; |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Utility to retrieve audio channel count value from pjmedia_port_info. |
| 253 | * |
| 254 | * @param pia Pointer to port info containing audio format. |
| 255 | * @return Audio channel count. |
| 256 | */ |
| 257 | PJ_INLINE(unsigned) PJMEDIA_PIA_CCNT(const pjmedia_port_info *pia) |
| 258 | { |
| 259 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 260 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 261 | return pia->fmt.det.aud.channel_count; |
| 262 | } |
| 263 | |
| 264 | /** |
| 265 | * Utility to retrieve audio bits per sample value from pjmedia_port_info. |
| 266 | * |
| 267 | * @param pia Pointer to port info containing audio format. |
| 268 | * @return Number of bits per sample. |
| 269 | */ |
| 270 | PJ_INLINE(unsigned) PJMEDIA_PIA_BITS(const pjmedia_port_info *pia) |
| 271 | { |
| 272 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 273 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 274 | return pia->fmt.det.aud.bits_per_sample; |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Utility to retrieve audio frame interval (ptime) value from |
| 279 | * pjmedia_port_info. |
| 280 | * |
| 281 | * @param pia Pointer to port info containing audio format. |
| 282 | * @return Frame interval in msec. |
| 283 | */ |
| 284 | PJ_INLINE(unsigned) PJMEDIA_PIA_PTIME(const pjmedia_port_info *pia) |
| 285 | { |
| 286 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 287 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 288 | return pia->fmt.det.aud.frame_time_usec / 1000; |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * This is a utility routine to retrieve the audio samples_per_frame value |
| 293 | * from port info. |
| 294 | * |
| 295 | * @param pia Pointer to port info containing audio format. |
| 296 | * @return Samples per frame value. |
| 297 | */ |
| 298 | PJ_INLINE(unsigned) PJMEDIA_PIA_SPF(const pjmedia_port_info *pia) |
| 299 | { |
| 300 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 301 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 302 | return PJMEDIA_AFD_SPF(&pia->fmt.det.aud); |
| 303 | } |
| 304 | |
| 305 | /** |
| 306 | * This is a utility routine to retrieve the average bitrate value |
| 307 | * from port info. |
| 308 | * |
| 309 | * @param pia Pointer to port info containing audio format. |
| 310 | * @return Bitrate, in bits per second. |
| 311 | */ |
| 312 | PJ_INLINE(unsigned) PJMEDIA_PIA_AVG_BPS(const pjmedia_port_info *pia) |
| 313 | { |
| 314 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 315 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 316 | return pia->fmt.det.aud.avg_bps; |
| 317 | } |
| 318 | |
| 319 | /** |
| 320 | * This is a utility routine to retrieve the maximum bitrate value |
| 321 | * from port info. |
| 322 | * |
| 323 | * @param pia Pointer to port info containing audio format. |
| 324 | * @return Bitrate, in bits per second. |
| 325 | */ |
| 326 | PJ_INLINE(unsigned) PJMEDIA_PIA_MAX_BPS(const pjmedia_port_info *pia) |
| 327 | { |
| 328 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 329 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 330 | return pia->fmt.det.aud.max_bps; |
| 331 | } |
| 332 | |
| 333 | /** |
| 334 | * This is a utility routine to retrieve the average audio frame size value |
| 335 | * from pjmedia_port_info. |
| 336 | * |
| 337 | * @param pia Pointer to port info containing audio format. |
| 338 | * @return Frame size in bytes. |
| 339 | */ |
| 340 | PJ_INLINE(unsigned) PJMEDIA_PIA_AVG_FSZ(const pjmedia_port_info *pia) |
| 341 | { |
| 342 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 343 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 344 | return PJMEDIA_AFD_AVG_FSZ(&pia->fmt.det.aud); |
| 345 | } |
| 346 | |
| 347 | /** |
| 348 | * Utility to retrieve audio frame size from maximum bitrate from |
| 349 | * pjmedia_port_info. |
| 350 | * |
| 351 | * @param pia Pointer to port info containing audio format. |
| 352 | * @return Frame size in bytes. |
| 353 | */ |
| 354 | PJ_INLINE(unsigned) PJMEDIA_PIA_MAX_FSZ(const pjmedia_port_info *pia) |
| 355 | { |
| 356 | pj_assert(pia->fmt.type==PJMEDIA_TYPE_AUDIO && |
| 357 | pia->fmt.detail_type==PJMEDIA_FORMAT_DETAIL_AUDIO); |
| 358 | return PJMEDIA_AFD_MAX_FSZ(&pia->fmt.det.aud); |
| 359 | } |
| 360 | |
| 361 | /** |
| 362 | * Port interface. |
| 363 | */ |
| 364 | typedef struct pjmedia_port |
| 365 | { |
| 366 | pjmedia_port_info info; /**< Port information. */ |
| 367 | |
| 368 | /** Port data can be used by the port creator to attach arbitrary |
| 369 | * value to be associated with the port. |
| 370 | */ |
| 371 | struct port_data { |
| 372 | void *pdata; /**< Pointer data. */ |
| 373 | long ldata; /**< Long data. */ |
| 374 | } port_data; |
| 375 | |
| 376 | /** |
| 377 | * Get clock source. |
| 378 | * This should only be called by #pjmedia_port_get_clock_src(). |
| 379 | */ |
| 380 | pjmedia_clock_src* (*get_clock_src)(struct pjmedia_port *this_port, |
| 381 | pjmedia_dir dir); |
| 382 | |
| 383 | /** |
| 384 | * Sink interface. |
| 385 | * This should only be called by #pjmedia_port_put_frame(). |
| 386 | */ |
| 387 | pj_status_t (*put_frame)(struct pjmedia_port *this_port, |
| 388 | pjmedia_frame *frame); |
| 389 | |
| 390 | /** |
| 391 | * Source interface. |
| 392 | * This should only be called by #pjmedia_port_get_frame(). |
| 393 | */ |
| 394 | pj_status_t (*get_frame)(struct pjmedia_port *this_port, |
| 395 | pjmedia_frame *frame); |
| 396 | |
| 397 | /** |
| 398 | * Called to destroy this port. |
| 399 | */ |
| 400 | pj_status_t (*on_destroy)(struct pjmedia_port *this_port); |
| 401 | |
| 402 | } pjmedia_port; |
| 403 | |
| 404 | |
| 405 | /** |
| 406 | * This is an auxiliary function to initialize port info for |
| 407 | * ports which deal with PCM audio. |
| 408 | * |
| 409 | * @param info The port info to be initialized. |
| 410 | * @param name Port name. |
| 411 | * @param signature Port signature. |
| 412 | * @param clock_rate Port's clock rate. |
| 413 | * @param channel_count Number of channels. |
| 414 | * @param bits_per_sample Bits per sample. |
| 415 | * @param samples_per_frame Number of samples per frame. |
| 416 | * |
| 417 | * @return PJ_SUCCESS on success. |
| 418 | */ |
| 419 | PJ_DECL(pj_status_t) pjmedia_port_info_init( pjmedia_port_info *info, |
| 420 | const pj_str_t *name, |
| 421 | unsigned signature, |
| 422 | unsigned clock_rate, |
| 423 | unsigned channel_count, |
| 424 | unsigned bits_per_sample, |
| 425 | unsigned samples_per_frame); |
| 426 | |
| 427 | /** |
| 428 | * This is an auxiliary function to initialize port info for |
| 429 | * ports which deal with PCM audio. |
| 430 | * |
| 431 | * @param info The port info to be initialized. |
| 432 | * @param name Port name. |
| 433 | * @param signature Port signature. |
| 434 | * @param dir Port's direction. |
| 435 | * @param fmt Port's media format. |
| 436 | * |
| 437 | * @return PJ_SUCCESS on success. |
| 438 | */ |
| 439 | PJ_DECL(pj_status_t) pjmedia_port_info_init2(pjmedia_port_info *info, |
| 440 | const pj_str_t *name, |
| 441 | unsigned signature, |
| 442 | pjmedia_dir dir, |
| 443 | const pjmedia_format *fmt); |
| 444 | |
| 445 | |
| 446 | /** |
| 447 | * Get a clock source from the port. |
| 448 | * |
| 449 | * @param port The media port. |
| 450 | * @param dir Media port's direction. |
| 451 | * |
| 452 | * @return The clock source or NULL if clock source is not present |
| 453 | * in the port. |
| 454 | */ |
| 455 | PJ_DECL(pjmedia_clock_src *) pjmedia_port_get_clock_src( pjmedia_port *port, |
| 456 | pjmedia_dir dir ); |
| 457 | |
| 458 | |
| 459 | /** |
| 460 | * Get a frame from the port (and subsequent downstream ports). |
| 461 | * |
| 462 | * @param port The media port. |
| 463 | * @param frame Frame to store samples. |
| 464 | * |
| 465 | * @return PJ_SUCCESS on success, or the appropriate error code. |
| 466 | */ |
| 467 | PJ_DECL(pj_status_t) pjmedia_port_get_frame( pjmedia_port *port, |
| 468 | pjmedia_frame *frame ); |
| 469 | |
| 470 | /** |
| 471 | * Put a frame to the port (and subsequent downstream ports). |
| 472 | * |
| 473 | * @param port The media port. |
| 474 | * @param frame Frame to the put to the port. |
| 475 | * |
| 476 | * @return PJ_SUCCESS on success, or the appropriate error code. |
| 477 | */ |
| 478 | PJ_DECL(pj_status_t) pjmedia_port_put_frame( pjmedia_port *port, |
| 479 | pjmedia_frame *frame ); |
| 480 | |
| 481 | /** |
| 482 | * Destroy port (and subsequent downstream ports) |
| 483 | * |
| 484 | * @param port The media port. |
| 485 | * |
| 486 | * @return PJ_SUCCESS on success, or the appropriate error code. |
| 487 | */ |
| 488 | PJ_DECL(pj_status_t) pjmedia_port_destroy( pjmedia_port *port ); |
| 489 | |
| 490 | |
| 491 | |
| 492 | PJ_END_DECL |
| 493 | |
| 494 | /** |
| 495 | * @} |
| 496 | */ |
| 497 | |
| 498 | #endif /* __PJMEDIA_PORT_H__ */ |
| 499 | |