1 /* 2 * Copyright (C) 2011-2013 Michael Niedermayer (michaelni@gmx.at) 3 * 4 * This file is part of libswresample 5 * 6 * libswresample is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * libswresample 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 GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with libswresample; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 #ifndef SWRESAMPLE_SWRESAMPLE_H 22 #define SWRESAMPLE_SWRESAMPLE_H 23 24 /** 25 * @file 26 * @ingroup lswr 27 * libswresample public header 28 */ 29 30 /** 31 * @defgroup lswr libswresample 32 * @{ 33 * 34 * Audio resampling, sample format conversion and mixing library. 35 * 36 * Interaction with lswr is done through SwrContext, which is 37 * allocated with swr_alloc() or swr_alloc_set_opts(). It is opaque, so all parameters 38 * must be set with the @ref avoptions API. 39 * 40 * The first thing you will need to do in order to use lswr is to allocate 41 * SwrContext. This can be done with swr_alloc() or swr_alloc_set_opts(). If you 42 * are using the former, you must set options through the @ref avoptions API. 43 * The latter function provides the same feature, but it allows you to set some 44 * common options in the same statement. 45 * 46 * For example the following code will setup conversion from planar float sample 47 * format to interleaved signed 16-bit integer, downsampling from 48kHz to 48 * 44.1kHz and downmixing from 5.1 channels to stereo (using the default mixing 49 * matrix). This is using the swr_alloc() function. 50 * @code 51 * SwrContext *swr = swr_alloc(); 52 * av_opt_set_channel_layout(swr, "in_channel_layout", AV_CH_LAYOUT_5POINT1, 0); 53 * av_opt_set_channel_layout(swr, "out_channel_layout", AV_CH_LAYOUT_STEREO, 0); 54 * av_opt_set_int(swr, "in_sample_rate", 48000, 0); 55 * av_opt_set_int(swr, "out_sample_rate", 44100, 0); 56 * av_opt_set_sample_fmt(swr, "in_sample_fmt", AV_SAMPLE_FMT_FLTP, 0); 57 * av_opt_set_sample_fmt(swr, "out_sample_fmt", AV_SAMPLE_FMT_S16, 0); 58 * @endcode 59 * 60 * The same job can be done using swr_alloc_set_opts() as well: 61 * @code 62 * SwrContext *swr = swr_alloc_set_opts(NULL, // we're allocating a new context 63 * AV_CH_LAYOUT_STEREO, // out_ch_layout 64 * AV_SAMPLE_FMT_S16, // out_sample_fmt 65 * 44100, // out_sample_rate 66 * AV_CH_LAYOUT_5POINT1, // in_ch_layout 67 * AV_SAMPLE_FMT_FLTP, // in_sample_fmt 68 * 48000, // in_sample_rate 69 * 0, // log_offset 70 * NULL); // log_ctx 71 * @endcode 72 * 73 * Once all values have been set, it must be initialized with swr_init(). If 74 * you need to change the conversion parameters, you can change the parameters 75 * using @ref AVOptions, as described above in the first example; or by using 76 * swr_alloc_set_opts(), but with the first argument the allocated context. 77 * You must then call swr_init() again. 78 * 79 * The conversion itself is done by repeatedly calling swr_convert(). 80 * Note that the samples may get buffered in swr if you provide insufficient 81 * output space or if sample rate conversion is done, which requires "future" 82 * samples. Samples that do not require future input can be retrieved at any 83 * time by using swr_convert() (in_count can be set to 0). 84 * At the end of conversion the resampling buffer can be flushed by calling 85 * swr_convert() with NULL in and 0 in_count. 86 * 87 * The samples used in the conversion process can be managed with the libavutil 88 * @ref lavu_sampmanip "samples manipulation" API, including av_samples_alloc() 89 * function used in the following example. 90 * 91 * The delay between input and output, can at any time be found by using 92 * swr_get_delay(). 93 * 94 * The following code demonstrates the conversion loop assuming the parameters 95 * from above and caller-defined functions get_input() and handle_output(): 96 * @code 97 * uint8_t **input; 98 * int in_samples; 99 * 100 * while (get_input(&input, &in_samples)) { 101 * uint8_t *output; 102 * int out_samples = av_rescale_rnd(swr_get_delay(swr, 48000) + 103 * in_samples, 44100, 48000, AV_ROUND_UP); 104 * av_samples_alloc(&output, NULL, 2, out_samples, 105 * AV_SAMPLE_FMT_S16, 0); 106 * out_samples = swr_convert(swr, &output, out_samples, 107 * input, in_samples); 108 * handle_output(output, out_samples); 109 * av_freep(&output); 110 * } 111 * @endcode 112 * 113 * When the conversion is finished, the conversion 114 * context and everything associated with it must be freed with swr_free(). 115 * A swr_close() function is also available, but it exists mainly for 116 * compatibility with libavresample, and is not required to be called. 117 * 118 * There will be no memory leak if the data is not completely flushed before 119 * swr_free(). 120 */ 121 122 #include <stdint.h> 123 #include "libavutil/channel_layout.h" 124 #include "libavutil/frame.h" 125 #include "libavutil/samplefmt.h" 126 127 #include "libswresample/version.h" 128 129 /** 130 * @name Option constants 131 * These constants are used for the @ref avoptions interface for lswr. 132 * @{ 133 * 134 */ 135 136 #define SWR_FLAG_RESAMPLE 1 ///< Force resampling even if equal sample rate 137 //TODO use int resample ? 138 //long term TODO can we enable this dynamically? 139 140 /** Dithering algorithms */ 141 enum SwrDitherType { 142 SWR_DITHER_NONE = 0, 143 SWR_DITHER_RECTANGULAR, 144 SWR_DITHER_TRIANGULAR, 145 SWR_DITHER_TRIANGULAR_HIGHPASS, 146 147 SWR_DITHER_NS = 64, ///< not part of API/ABI 148 SWR_DITHER_NS_LIPSHITZ, 149 SWR_DITHER_NS_F_WEIGHTED, 150 SWR_DITHER_NS_MODIFIED_E_WEIGHTED, 151 SWR_DITHER_NS_IMPROVED_E_WEIGHTED, 152 SWR_DITHER_NS_SHIBATA, 153 SWR_DITHER_NS_LOW_SHIBATA, 154 SWR_DITHER_NS_HIGH_SHIBATA, 155 SWR_DITHER_NB, ///< not part of API/ABI 156 }; 157 158 /** Resampling Engines */ 159 enum SwrEngine { 160 SWR_ENGINE_SWR, /**< SW Resampler */ 161 SWR_ENGINE_SOXR, /**< SoX Resampler */ 162 SWR_ENGINE_NB, ///< not part of API/ABI 163 }; 164 165 /** Resampling Filter Types */ 166 enum SwrFilterType { 167 SWR_FILTER_TYPE_CUBIC, /**< Cubic */ 168 SWR_FILTER_TYPE_BLACKMAN_NUTTALL, /**< Blackman Nuttall windowed sinc */ 169 SWR_FILTER_TYPE_KAISER, /**< Kaiser windowed sinc */ 170 }; 171 172 /** 173 * @} 174 */ 175 176 /** 177 * The libswresample context. Unlike libavcodec and libavformat, this structure 178 * is opaque. This means that if you would like to set options, you must use 179 * the @ref avoptions API and cannot directly set values to members of the 180 * structure. 181 */ 182 typedef struct SwrContext SwrContext; 183 184 /** 185 * Get the AVClass for SwrContext. It can be used in combination with 186 * AV_OPT_SEARCH_FAKE_OBJ for examining options. 187 * 188 * @see av_opt_find(). 189 * @return the AVClass of SwrContext 190 */ 191 const AVClass *swr_get_class(void); 192 193 /** 194 * @name SwrContext constructor functions 195 * @{ 196 */ 197 198 /** 199 * Allocate SwrContext. 200 * 201 * If you use this function you will need to set the parameters (manually or 202 * with swr_alloc_set_opts()) before calling swr_init(). 203 * 204 * @see swr_alloc_set_opts(), swr_init(), swr_free() 205 * @return NULL on error, allocated context otherwise 206 */ 207 struct SwrContext *swr_alloc(void); 208 209 /** 210 * Initialize context after user parameters have been set. 211 * @note The context must be configured using the AVOption API. 212 * 213 * @see av_opt_set_int() 214 * @see av_opt_set_dict() 215 * 216 * @param[in,out] s Swr context to initialize 217 * @return AVERROR error code in case of failure. 218 */ 219 int swr_init(struct SwrContext *s); 220 221 /** 222 * Check whether an swr context has been initialized or not. 223 * 224 * @param[in] s Swr context to check 225 * @see swr_init() 226 * @return positive if it has been initialized, 0 if not initialized 227 */ 228 int swr_is_initialized(struct SwrContext *s); 229 230 /** 231 * Allocate SwrContext if needed and set/reset common parameters. 232 * 233 * This function does not require s to be allocated with swr_alloc(). On the 234 * other hand, swr_alloc() can use swr_alloc_set_opts() to set the parameters 235 * on the allocated context. 236 * 237 * @param s existing Swr context if available, or NULL if not 238 * @param out_ch_layout output channel layout (AV_CH_LAYOUT_*) 239 * @param out_sample_fmt output sample format (AV_SAMPLE_FMT_*). 240 * @param out_sample_rate output sample rate (frequency in Hz) 241 * @param in_ch_layout input channel layout (AV_CH_LAYOUT_*) 242 * @param in_sample_fmt input sample format (AV_SAMPLE_FMT_*). 243 * @param in_sample_rate input sample rate (frequency in Hz) 244 * @param log_offset logging level offset 245 * @param log_ctx parent logging context, can be NULL 246 * 247 * @see swr_init(), swr_free() 248 * @return NULL on error, allocated context otherwise 249 */ 250 struct SwrContext *swr_alloc_set_opts(struct SwrContext *s, 251 int64_t out_ch_layout, enum AVSampleFormat out_sample_fmt, int out_sample_rate, 252 int64_t in_ch_layout, enum AVSampleFormat in_sample_fmt, int in_sample_rate, 253 int log_offset, void *log_ctx); 254 255 /** 256 * @} 257 * 258 * @name SwrContext destructor functions 259 * @{ 260 */ 261 262 /** 263 * Free the given SwrContext and set the pointer to NULL. 264 * 265 * @param[in] s a pointer to a pointer to Swr context 266 */ 267 void swr_free(struct SwrContext **s); 268 269 /** 270 * Closes the context so that swr_is_initialized() returns 0. 271 * 272 * The context can be brought back to life by running swr_init(), 273 * swr_init() can also be used without swr_close(). 274 * This function is mainly provided for simplifying the usecase 275 * where one tries to support libavresample and libswresample. 276 * 277 * @param[in,out] s Swr context to be closed 278 */ 279 void swr_close(struct SwrContext *s); 280 281 /** 282 * @} 283 * 284 * @name Core conversion functions 285 * @{ 286 */ 287 288 /** Convert audio. 289 * 290 * in and in_count can be set to 0 to flush the last few samples out at the 291 * end. 292 * 293 * If more input is provided than output space, then the input will be buffered. 294 * You can avoid this buffering by using swr_get_out_samples() to retrieve an 295 * upper bound on the required number of output samples for the given number of 296 * input samples. Conversion will run directly without copying whenever possible. 297 * 298 * @param s allocated Swr context, with parameters set 299 * @param out output buffers, only the first one need be set in case of packed audio 300 * @param out_count amount of space available for output in samples per channel 301 * @param in input buffers, only the first one need to be set in case of packed audio 302 * @param in_count number of input samples available in one channel 303 * 304 * @return number of samples output per channel, negative value on error 305 */ 306 int swr_convert(struct SwrContext *s, uint8_t **out, int out_count, 307 const uint8_t **in , int in_count); 308 309 /** 310 * Convert the next timestamp from input to output 311 * timestamps are in 1/(in_sample_rate * out_sample_rate) units. 312 * 313 * @note There are 2 slightly differently behaving modes. 314 * @li When automatic timestamp compensation is not used, (min_compensation >= FLT_MAX) 315 * in this case timestamps will be passed through with delays compensated 316 * @li When automatic timestamp compensation is used, (min_compensation < FLT_MAX) 317 * in this case the output timestamps will match output sample numbers. 318 * See ffmpeg-resampler(1) for the two modes of compensation. 319 * 320 * @param s[in] initialized Swr context 321 * @param pts[in] timestamp for the next input sample, INT64_MIN if unknown 322 * @see swr_set_compensation(), swr_drop_output(), and swr_inject_silence() are 323 * function used internally for timestamp compensation. 324 * @return the output timestamp for the next output sample 325 */ 326 int64_t swr_next_pts(struct SwrContext *s, int64_t pts); 327 328 /** 329 * @} 330 * 331 * @name Low-level option setting functions 332 * These functons provide a means to set low-level options that is not possible 333 * with the AVOption API. 334 * @{ 335 */ 336 337 /** 338 * Activate resampling compensation ("soft" compensation). This function is 339 * internally called when needed in swr_next_pts(). 340 * 341 * @param[in,out] s allocated Swr context. If it is not initialized, 342 * or SWR_FLAG_RESAMPLE is not set, swr_init() is 343 * called with the flag set. 344 * @param[in] sample_delta delta in PTS per sample 345 * @param[in] compensation_distance number of samples to compensate for 346 * @return >= 0 on success, AVERROR error codes if: 347 * @li @c s is NULL, 348 * @li @c compensation_distance is less than 0, 349 * @li @c compensation_distance is 0 but sample_delta is not, 350 * @li compensation unsupported by resampler, or 351 * @li swr_init() fails when called. 352 */ 353 int swr_set_compensation(struct SwrContext *s, int sample_delta, int compensation_distance); 354 355 /** 356 * Set a customized input channel mapping. 357 * 358 * @param[in,out] s allocated Swr context, not yet initialized 359 * @param[in] channel_map customized input channel mapping (array of channel 360 * indexes, -1 for a muted channel) 361 * @return >= 0 on success, or AVERROR error code in case of failure. 362 */ 363 int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map); 364 365 /** 366 * Generate a channel mixing matrix. 367 * 368 * This function is the one used internally by libswresample for building the 369 * default mixing matrix. It is made public just as a utility function for 370 * building custom matrices. 371 * 372 * @param in_layout input channel layout 373 * @param out_layout output channel layout 374 * @param center_mix_level mix level for the center channel 375 * @param surround_mix_level mix level for the surround channel(s) 376 * @param lfe_mix_level mix level for the low-frequency effects channel 377 * @param rematrix_maxval if 1.0, coefficients will be normalized to prevent 378 * overflow. if INT_MAX, coefficients will not be 379 * normalized. 380 * @param[out] matrix mixing coefficients; matrix[i + stride * o] is 381 * the weight of input channel i in output channel o. 382 * @param stride distance between adjacent input channels in the 383 * matrix array 384 * @param matrix_encoding matrixed stereo downmix mode (e.g. dplii) 385 * @param log_ctx parent logging context, can be NULL 386 * @return 0 on success, negative AVERROR code on failure 387 */ 388 int swr_build_matrix(uint64_t in_layout, uint64_t out_layout, 389 double center_mix_level, double surround_mix_level, 390 double lfe_mix_level, double rematrix_maxval, 391 double rematrix_volume, double *matrix, 392 int stride, enum AVMatrixEncoding matrix_encoding, 393 void *log_ctx); 394 395 /** 396 * Set a customized remix matrix. 397 * 398 * @param s allocated Swr context, not yet initialized 399 * @param matrix remix coefficients; matrix[i + stride * o] is 400 * the weight of input channel i in output channel o 401 * @param stride offset between lines of the matrix 402 * @return >= 0 on success, or AVERROR error code in case of failure. 403 */ 404 int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride); 405 406 /** 407 * @} 408 * 409 * @name Sample handling functions 410 * @{ 411 */ 412 413 /** 414 * Drops the specified number of output samples. 415 * 416 * This function, along with swr_inject_silence(), is called by swr_next_pts() 417 * if needed for "hard" compensation. 418 * 419 * @param s allocated Swr context 420 * @param count number of samples to be dropped 421 * 422 * @return >= 0 on success, or a negative AVERROR code on failure 423 */ 424 int swr_drop_output(struct SwrContext *s, int count); 425 426 /** 427 * Injects the specified number of silence samples. 428 * 429 * This function, along with swr_drop_output(), is called by swr_next_pts() 430 * if needed for "hard" compensation. 431 * 432 * @param s allocated Swr context 433 * @param count number of samples to be dropped 434 * 435 * @return >= 0 on success, or a negative AVERROR code on failure 436 */ 437 int swr_inject_silence(struct SwrContext *s, int count); 438 439 /** 440 * Gets the delay the next input sample will experience relative to the next output sample. 441 * 442 * Swresample can buffer data if more input has been provided than available 443 * output space, also converting between sample rates needs a delay. 444 * This function returns the sum of all such delays. 445 * The exact delay is not necessarily an integer value in either input or 446 * output sample rate. Especially when downsampling by a large value, the 447 * output sample rate may be a poor choice to represent the delay, similarly 448 * for upsampling and the input sample rate. 449 * 450 * @param s swr context 451 * @param base timebase in which the returned delay will be: 452 * @li if it's set to 1 the returned delay is in seconds 453 * @li if it's set to 1000 the returned delay is in milliseconds 454 * @li if it's set to the input sample rate then the returned 455 * delay is in input samples 456 * @li if it's set to the output sample rate then the returned 457 * delay is in output samples 458 * @li if it's the least common multiple of in_sample_rate and 459 * out_sample_rate then an exact rounding-free delay will be 460 * returned 461 * @returns the delay in 1 / @c base units. 462 */ 463 int64_t swr_get_delay(struct SwrContext *s, int64_t base); 464 465 /** 466 * Find an upper bound on the number of samples that the next swr_convert 467 * call will output, if called with in_samples of input samples. This 468 * depends on the internal state, and anything changing the internal state 469 * (like further swr_convert() calls) will may change the number of samples 470 * swr_get_out_samples() returns for the same number of input samples. 471 * 472 * @param in_samples number of input samples. 473 * @note any call to swr_inject_silence(), swr_convert(), swr_next_pts() 474 * or swr_set_compensation() invalidates this limit 475 * @note it is recommended to pass the correct available buffer size 476 * to all functions like swr_convert() even if swr_get_out_samples() 477 * indicates that less would be used. 478 * @returns an upper bound on the number of samples that the next swr_convert 479 * will output or a negative value to indicate an error 480 */ 481 int swr_get_out_samples(struct SwrContext *s, int in_samples); 482 483 /** 484 * @} 485 * 486 * @name Configuration accessors 487 * @{ 488 */ 489 490 /** 491 * Return the @ref LIBSWRESAMPLE_VERSION_INT constant. 492 * 493 * This is useful to check if the build-time libswresample has the same version 494 * as the run-time one. 495 * 496 * @returns the unsigned int-typed version 497 */ 498 unsigned swresample_version(void); 499 500 /** 501 * Return the swr build-time configuration. 502 * 503 * @returns the build-time @c ./configure flags 504 */ 505 const char *swresample_configuration(void); 506 507 /** 508 * Return the swr license. 509 * 510 * @returns the license of libswresample, determined at build-time 511 */ 512 const char *swresample_license(void); 513 514 /** 515 * @} 516 * 517 * @name AVFrame based API 518 * @{ 519 */ 520 521 /** 522 * Convert the samples in the input AVFrame and write them to the output AVFrame. 523 * 524 * Input and output AVFrames must have channel_layout, sample_rate and format set. 525 * 526 * If the output AVFrame does not have the data pointers allocated the nb_samples 527 * field will be set using av_frame_get_buffer() 528 * is called to allocate the frame. 529 * 530 * The output AVFrame can be NULL or have fewer allocated samples than required. 531 * In this case, any remaining samples not written to the output will be added 532 * to an internal FIFO buffer, to be returned at the next call to this function 533 * or to swr_convert(). 534 * 535 * If converting sample rate, there may be data remaining in the internal 536 * resampling delay buffer. swr_get_delay() tells the number of 537 * remaining samples. To get this data as output, call this function or 538 * swr_convert() with NULL input. 539 * 540 * If the SwrContext configuration does not match the output and 541 * input AVFrame settings the conversion does not take place and depending on 542 * which AVFrame is not matching AVERROR_OUTPUT_CHANGED, AVERROR_INPUT_CHANGED 543 * or the result of a bitwise-OR of them is returned. 544 * 545 * @see swr_delay() 546 * @see swr_convert() 547 * @see swr_get_delay() 548 * 549 * @param swr audio resample context 550 * @param output output AVFrame 551 * @param input input AVFrame 552 * @return 0 on success, AVERROR on failure or nonmatching 553 * configuration. 554 */ 555 int swr_convert_frame(SwrContext *swr, 556 AVFrame *output, const AVFrame *input); 557 558 /** 559 * Configure or reconfigure the SwrContext using the information 560 * provided by the AVFrames. 561 * 562 * The original resampling context is reset even on failure. 563 * The function calls swr_close() internally if the context is open. 564 * 565 * @see swr_close(); 566 * 567 * @param swr audio resample context 568 * @param output output AVFrame 569 * @param input input AVFrame 570 * @return 0 on success, AVERROR on failure. 571 */ 572 int swr_config_frame(SwrContext *swr, const AVFrame *out, const AVFrame *in); 573 574 /** 575 * @} 576 * @} 577 */ 578 579 #endif /* SWRESAMPLE_SWRESAMPLE_H */ 580