1 /* 2 * AVOptions 3 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 #ifndef AVUTIL_OPT_H 23 #define AVUTIL_OPT_H 24 25 /** 26 * @file 27 * AVOptions 28 */ 29 30 #include "rational.h" 31 #include "avutil.h" 32 #include "dict.h" 33 #include "log.h" 34 #include "pixfmt.h" 35 #include "samplefmt.h" 36 37 /** 38 * @defgroup avoptions AVOptions 39 * @ingroup lavu_data 40 * @{ 41 * AVOptions provide a generic system to declare options on arbitrary structs 42 * ("objects"). An option can have a help text, a type and a range of possible 43 * values. Options may then be enumerated, read and written to. 44 * 45 * @section avoptions_implement Implementing AVOptions 46 * This section describes how to add AVOptions capabilities to a struct. 47 * 48 * All AVOptions-related information is stored in an AVClass. Therefore 49 * the first member of the struct should be a pointer to an AVClass describing it. 50 * The option field of the AVClass must be set to a NULL-terminated static array 51 * of AVOptions. Each AVOption must have a non-empty name, a type, a default 52 * value and for number-type AVOptions also a range of allowed values. It must 53 * also declare an offset in bytes from the start of the struct, where the field 54 * associated with this AVOption is located. Other fields in the AVOption struct 55 * should also be set when applicable, but are not required. 56 * 57 * The following example illustrates an AVOptions-enabled struct: 58 * @code 59 * typedef struct test_struct { 60 * AVClass *class; 61 * int int_opt; 62 * char *str_opt; 63 * uint8_t *bin_opt; 64 * int bin_len; 65 * } test_struct; 66 * 67 * static const AVOption test_options[] = { 68 * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt), 69 * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX }, 70 * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt), 71 * AV_OPT_TYPE_STRING }, 72 * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt), 73 * AV_OPT_TYPE_BINARY }, 74 * { NULL }, 75 * }; 76 * 77 * static const AVClass test_class = { 78 * .class_name = "test class", 79 * .item_name = av_default_item_name, 80 * .option = test_options, 81 * .version = LIBAVUTIL_VERSION_INT, 82 * }; 83 * @endcode 84 * 85 * Next, when allocating your struct, you must ensure that the AVClass pointer 86 * is set to the correct value. Then, av_opt_set_defaults() can be called to 87 * initialize defaults. After that the struct is ready to be used with the 88 * AVOptions API. 89 * 90 * When cleaning up, you may use the av_opt_free() function to automatically 91 * free all the allocated string and binary options. 92 * 93 * Continuing with the above example: 94 * 95 * @code 96 * test_struct *alloc_test_struct(void) 97 * { 98 * test_struct *ret = av_malloc(sizeof(*ret)); 99 * ret->class = &test_class; 100 * av_opt_set_defaults(ret); 101 * return ret; 102 * } 103 * void free_test_struct(test_struct **foo) 104 * { 105 * av_opt_free(*foo); 106 * av_freep(foo); 107 * } 108 * @endcode 109 * 110 * @subsection avoptions_implement_nesting Nesting 111 * It may happen that an AVOptions-enabled struct contains another 112 * AVOptions-enabled struct as a member (e.g. AVCodecContext in 113 * libavcodec exports generic options, while its priv_data field exports 114 * codec-specific options). In such a case, it is possible to set up the 115 * parent struct to export a child's options. To do that, simply 116 * implement AVClass.child_next() and AVClass.child_class_next() in the 117 * parent struct's AVClass. 118 * Assuming that the test_struct from above now also contains a 119 * child_struct field: 120 * 121 * @code 122 * typedef struct child_struct { 123 * AVClass *class; 124 * int flags_opt; 125 * } child_struct; 126 * static const AVOption child_opts[] = { 127 * { "test_flags", "This is a test option of flags type.", 128 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX }, 129 * { NULL }, 130 * }; 131 * static const AVClass child_class = { 132 * .class_name = "child class", 133 * .item_name = av_default_item_name, 134 * .option = child_opts, 135 * .version = LIBAVUTIL_VERSION_INT, 136 * }; 137 * 138 * void *child_next(void *obj, void *prev) 139 * { 140 * test_struct *t = obj; 141 * if (!prev && t->child_struct) 142 * return t->child_struct; 143 * return NULL 144 * } 145 * const AVClass child_class_next(const AVClass *prev) 146 * { 147 * return prev ? NULL : &child_class; 148 * } 149 * @endcode 150 * Putting child_next() and child_class_next() as defined above into 151 * test_class will now make child_struct's options accessible through 152 * test_struct (again, proper setup as described above needs to be done on 153 * child_struct right after it is created). 154 * 155 * From the above example it might not be clear why both child_next() 156 * and child_class_next() are needed. The distinction is that child_next() 157 * iterates over actually existing objects, while child_class_next() 158 * iterates over all possible child classes. E.g. if an AVCodecContext 159 * was initialized to use a codec which has private options, then its 160 * child_next() will return AVCodecContext.priv_data and finish 161 * iterating. OTOH child_class_next() on AVCodecContext.av_class will 162 * iterate over all available codecs with private options. 163 * 164 * @subsection avoptions_implement_named_constants Named constants 165 * It is possible to create named constants for options. Simply set the unit 166 * field of the option the constants should apply to a string and 167 * create the constants themselves as options of type AV_OPT_TYPE_CONST 168 * with their unit field set to the same string. 169 * Their default_val field should contain the value of the named 170 * constant. 171 * For example, to add some named constants for the test_flags option 172 * above, put the following into the child_opts array: 173 * @code 174 * { "test_flags", "This is a test option of flags type.", 175 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" }, 176 * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" }, 177 * @endcode 178 * 179 * @section avoptions_use Using AVOptions 180 * This section deals with accessing options in an AVOptions-enabled struct. 181 * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or 182 * AVFormatContext in libavformat. 183 * 184 * @subsection avoptions_use_examine Examining AVOptions 185 * The basic functions for examining options are av_opt_next(), which iterates 186 * over all options defined for one object, and av_opt_find(), which searches 187 * for an option with the given name. 188 * 189 * The situation is more complicated with nesting. An AVOptions-enabled struct 190 * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag 191 * to av_opt_find() will make the function search children recursively. 192 * 193 * For enumerating there are basically two cases. The first is when you want to 194 * get all options that may potentially exist on the struct and its children 195 * (e.g. when constructing documentation). In that case you should call 196 * av_opt_child_class_next() recursively on the parent struct's AVClass. The 197 * second case is when you have an already initialized struct with all its 198 * children and you want to get all options that can be actually written or read 199 * from it. In that case you should call av_opt_child_next() recursively (and 200 * av_opt_next() on each result). 201 * 202 * @subsection avoptions_use_get_set Reading and writing AVOptions 203 * When setting options, you often have a string read directly from the 204 * user. In such a case, simply passing it to av_opt_set() is enough. For 205 * non-string type options, av_opt_set() will parse the string according to the 206 * option type. 207 * 208 * Similarly av_opt_get() will read any option type and convert it to a string 209 * which will be returned. Do not forget that the string is allocated, so you 210 * have to free it with av_free(). 211 * 212 * In some cases it may be more convenient to put all options into an 213 * AVDictionary and call av_opt_set_dict() on it. A specific case of this 214 * are the format/codec open functions in lavf/lavc which take a dictionary 215 * filled with option as a parameter. This allows to set some options 216 * that cannot be set otherwise, since e.g. the input file format is not known 217 * before the file is actually opened. 218 */ 219 220 enum AVOptionType{ 221 AV_OPT_TYPE_FLAGS, 222 AV_OPT_TYPE_INT, 223 AV_OPT_TYPE_INT64, 224 AV_OPT_TYPE_DOUBLE, 225 AV_OPT_TYPE_FLOAT, 226 AV_OPT_TYPE_STRING, 227 AV_OPT_TYPE_RATIONAL, 228 AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length 229 AV_OPT_TYPE_DICT, 230 AV_OPT_TYPE_CONST = 128, 231 AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers 232 AV_OPT_TYPE_PIXEL_FMT = MKBETAG('P','F','M','T'), 233 AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'), 234 AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational 235 AV_OPT_TYPE_DURATION = MKBETAG('D','U','R',' '), 236 AV_OPT_TYPE_COLOR = MKBETAG('C','O','L','R'), 237 AV_OPT_TYPE_CHANNEL_LAYOUT = MKBETAG('C','H','L','A'), 238 #if FF_API_OLD_AVOPTIONS 239 FF_OPT_TYPE_FLAGS = 0, 240 FF_OPT_TYPE_INT, 241 FF_OPT_TYPE_INT64, 242 FF_OPT_TYPE_DOUBLE, 243 FF_OPT_TYPE_FLOAT, 244 FF_OPT_TYPE_STRING, 245 FF_OPT_TYPE_RATIONAL, 246 FF_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length 247 FF_OPT_TYPE_CONST=128, 248 #endif 249 }; 250 251 /** 252 * AVOption 253 */ 254 typedef struct AVOption { 255 const char *name; 256 257 /** 258 * short English help text 259 * @todo What about other languages? 260 */ 261 const char *help; 262 263 /** 264 * The offset relative to the context structure where the option 265 * value is stored. It should be 0 for named constants. 266 */ 267 int offset; 268 enum AVOptionType type; 269 270 /** 271 * the default value for scalar options 272 */ 273 union { 274 int64_t i64; 275 double dbl; 276 const char *str; 277 /* TODO those are unused now */ 278 AVRational q; 279 } default_val; 280 double min; ///< minimum valid value for the option 281 double max; ///< maximum valid value for the option 282 283 int flags; 284 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding 285 #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding 286 #if FF_API_OPT_TYPE_METADATA 287 #define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ... 288 #endif 289 #define AV_OPT_FLAG_AUDIO_PARAM 8 290 #define AV_OPT_FLAG_VIDEO_PARAM 16 291 #define AV_OPT_FLAG_SUBTITLE_PARAM 32 292 /** 293 * The option is inteded for exporting values to the caller. 294 */ 295 #define AV_OPT_FLAG_EXPORT 64 296 /** 297 * The option may not be set through the AVOptions API, only read. 298 * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set. 299 */ 300 #define AV_OPT_FLAG_READONLY 128 301 #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering 302 //FIXME think about enc-audio, ... style flags 303 304 /** 305 * The logical unit to which the option belongs. Non-constant 306 * options and corresponding named constants share the same 307 * unit. May be NULL. 308 */ 309 const char *unit; 310 } AVOption; 311 312 /** 313 * A single allowed range of values, or a single allowed value. 314 */ 315 typedef struct AVOptionRange { 316 const char *str; 317 /** 318 * Value range. 319 * For string ranges this represents the min/max length. 320 * For dimensions this represents the min/max pixel count or width/height in multi-component case. 321 */ 322 double value_min, value_max; 323 /** 324 * Value's component range. 325 * For string this represents the unicode range for chars, 0-127 limits to ASCII. 326 */ 327 double component_min, component_max; 328 /** 329 * Range flag. 330 * If set to 1 the struct encodes a range, if set to 0 a single value. 331 */ 332 int is_range; 333 } AVOptionRange; 334 335 /** 336 * List of AVOptionRange structs. 337 */ 338 typedef struct AVOptionRanges { 339 /** 340 * Array of option ranges. 341 * 342 * Most of option types use just one component. 343 * Following describes multi-component option types: 344 * 345 * AV_OPT_TYPE_IMAGE_SIZE: 346 * component index 0: range of pixel count (width * height). 347 * component index 1: range of width. 348 * component index 2: range of height. 349 * 350 * @note To obtain multi-component version of this structure, user must 351 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or 352 * av_opt_query_ranges_default function. 353 * 354 * Multi-component range can be read as in following example: 355 * 356 * @code 357 * int range_index, component_index; 358 * AVOptionRanges *ranges; 359 * AVOptionRange *range[3]; //may require more than 3 in the future. 360 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE); 361 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) { 362 * for (component_index = 0; component_index < ranges->nb_components; component_index++) 363 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index]; 364 * //do something with range here. 365 * } 366 * av_opt_freep_ranges(&ranges); 367 * @endcode 368 */ 369 AVOptionRange **range; 370 /** 371 * Number of ranges per component. 372 */ 373 int nb_ranges; 374 /** 375 * Number of componentes. 376 */ 377 int nb_components; 378 } AVOptionRanges; 379 380 381 #if FF_API_OLD_AVOPTIONS 382 /** 383 * Set the field of obj with the given name to value. 384 * 385 * @param[in] obj A struct whose first element is a pointer to an 386 * AVClass. 387 * @param[in] name the name of the field to set 388 * @param[in] val The value to set. If the field is not of a string 389 * type, then the given string is parsed. 390 * SI postfixes and some named scalars are supported. 391 * If the field is of a numeric type, it has to be a numeric or named 392 * scalar. Behavior with more than one scalar and +- infix operators 393 * is undefined. 394 * If the field is of a flags type, it has to be a sequence of numeric 395 * scalars or named flags separated by '+' or '-'. Prefixing a flag 396 * with '+' causes it to be set without affecting the other flags; 397 * similarly, '-' unsets a flag. 398 * @param[out] o_out if non-NULL put here a pointer to the AVOption 399 * found 400 * @param alloc this parameter is currently ignored 401 * @return 0 if the value has been set, or an AVERROR code in case of 402 * error: 403 * AVERROR_OPTION_NOT_FOUND if no matching option exists 404 * AVERROR(ERANGE) if the value is out of range 405 * AVERROR(EINVAL) if the value is not valid 406 * @deprecated use av_opt_set() 407 */ 408 attribute_deprecated 409 int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out); 410 411 attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n); 412 attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n); 413 attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n); 414 415 double av_get_double(void *obj, const char *name, const AVOption **o_out); 416 AVRational av_get_q(void *obj, const char *name, const AVOption **o_out); 417 int64_t av_get_int(void *obj, const char *name, const AVOption **o_out); 418 attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len); 419 attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last); 420 #endif 421 422 /** 423 * Show the obj options. 424 * 425 * @param req_flags requested flags for the options to show. Show only the 426 * options for which it is opt->flags & req_flags. 427 * @param rej_flags rejected flags for the options to show. Show only the 428 * options for which it is !(opt->flags & req_flags). 429 * @param av_log_obj log context to use for showing the options 430 */ 431 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags); 432 433 /** 434 * Set the values of all AVOption fields to their default values. 435 * 436 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) 437 */ 438 void av_opt_set_defaults(void *s); 439 440 #if FF_API_OLD_AVOPTIONS 441 attribute_deprecated 442 void av_opt_set_defaults2(void *s, int mask, int flags); 443 #endif 444 445 /** 446 * Parse the key/value pairs list in opts. For each key/value pair 447 * found, stores the value in the field in ctx that is named like the 448 * key. ctx must be an AVClass context, storing is done using 449 * AVOptions. 450 * 451 * @param opts options string to parse, may be NULL 452 * @param key_val_sep a 0-terminated list of characters used to 453 * separate key from value 454 * @param pairs_sep a 0-terminated list of characters used to separate 455 * two pairs from each other 456 * @return the number of successfully set key/value pairs, or a negative 457 * value corresponding to an AVERROR code in case of error: 458 * AVERROR(EINVAL) if opts cannot be parsed, 459 * the error code issued by av_opt_set() if a key/value pair 460 * cannot be set 461 */ 462 int av_set_options_string(void *ctx, const char *opts, 463 const char *key_val_sep, const char *pairs_sep); 464 465 /** 466 * Parse the key-value pairs list in opts. For each key=value pair found, 467 * set the value of the corresponding option in ctx. 468 * 469 * @param ctx the AVClass object to set options on 470 * @param opts the options string, key-value pairs separated by a 471 * delimiter 472 * @param shorthand a NULL-terminated array of options names for shorthand 473 * notation: if the first field in opts has no key part, 474 * the key is taken from the first element of shorthand; 475 * then again for the second, etc., until either opts is 476 * finished, shorthand is finished or a named option is 477 * found; after that, all options must be named 478 * @param key_val_sep a 0-terminated list of characters used to separate 479 * key from value, for example '=' 480 * @param pairs_sep a 0-terminated list of characters used to separate 481 * two pairs from each other, for example ':' or ',' 482 * @return the number of successfully set key=value pairs, or a negative 483 * value corresponding to an AVERROR code in case of error: 484 * AVERROR(EINVAL) if opts cannot be parsed, 485 * the error code issued by av_set_string3() if a key/value pair 486 * cannot be set 487 * 488 * Options names must use only the following characters: a-z A-Z 0-9 - . / _ 489 * Separators must use characters distinct from option names and from each 490 * other. 491 */ 492 int av_opt_set_from_string(void *ctx, const char *opts, 493 const char *const *shorthand, 494 const char *key_val_sep, const char *pairs_sep); 495 /** 496 * Free all allocated objects in obj. 497 */ 498 void av_opt_free(void *obj); 499 500 /** 501 * Check whether a particular flag is set in a flags field. 502 * 503 * @param field_name the name of the flag field option 504 * @param flag_name the name of the flag to check 505 * @return non-zero if the flag is set, zero if the flag isn't set, 506 * isn't of the right type, or the flags field doesn't exist. 507 */ 508 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name); 509 510 /** 511 * Set all the options from a given dictionary on an object. 512 * 513 * @param obj a struct whose first element is a pointer to AVClass 514 * @param options options to process. This dictionary will be freed and replaced 515 * by a new one containing all options not found in obj. 516 * Of course this new dictionary needs to be freed by caller 517 * with av_dict_free(). 518 * 519 * @return 0 on success, a negative AVERROR if some option was found in obj, 520 * but could not be set. 521 * 522 * @see av_dict_copy() 523 */ 524 int av_opt_set_dict(void *obj, struct AVDictionary **options); 525 526 527 /** 528 * Set all the options from a given dictionary on an object. 529 * 530 * @param obj a struct whose first element is a pointer to AVClass 531 * @param options options to process. This dictionary will be freed and replaced 532 * by a new one containing all options not found in obj. 533 * Of course this new dictionary needs to be freed by caller 534 * with av_dict_free(). 535 * @param search_flags A combination of AV_OPT_SEARCH_*. 536 * 537 * @return 0 on success, a negative AVERROR if some option was found in obj, 538 * but could not be set. 539 * 540 * @see av_dict_copy() 541 */ 542 int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags); 543 544 /** 545 * Extract a key-value pair from the beginning of a string. 546 * 547 * @param ropts pointer to the options string, will be updated to 548 * point to the rest of the string (one of the pairs_sep 549 * or the final NUL) 550 * @param key_val_sep a 0-terminated list of characters used to separate 551 * key from value, for example '=' 552 * @param pairs_sep a 0-terminated list of characters used to separate 553 * two pairs from each other, for example ':' or ',' 554 * @param flags flags; see the AV_OPT_FLAG_* values below 555 * @param rkey parsed key; must be freed using av_free() 556 * @param rval parsed value; must be freed using av_free() 557 * 558 * @return >=0 for success, or a negative value corresponding to an 559 * AVERROR code in case of error; in particular: 560 * AVERROR(EINVAL) if no key is present 561 * 562 */ 563 int av_opt_get_key_value(const char **ropts, 564 const char *key_val_sep, const char *pairs_sep, 565 unsigned flags, 566 char **rkey, char **rval); 567 568 enum { 569 570 /** 571 * Accept to parse a value without a key; the key will then be returned 572 * as NULL. 573 */ 574 AV_OPT_FLAG_IMPLICIT_KEY = 1, 575 }; 576 577 /** 578 * @defgroup opt_eval_funcs Evaluating option strings 579 * @{ 580 * This group of functions can be used to evaluate option strings 581 * and get numbers out of them. They do the same thing as av_opt_set(), 582 * except the result is written into the caller-supplied pointer. 583 * 584 * @param obj a struct whose first element is a pointer to AVClass. 585 * @param o an option for which the string is to be evaluated. 586 * @param val string to be evaluated. 587 * @param *_out value of the string will be written here. 588 * 589 * @return 0 on success, a negative number on failure. 590 */ 591 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out); 592 int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out); 593 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out); 594 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out); 595 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out); 596 int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out); 597 /** 598 * @} 599 */ 600 601 #define AV_OPT_SEARCH_CHILDREN 0x0001 /**< Search in possible children of the 602 given object first. */ 603 /** 604 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass 605 * instead of a required pointer to a struct containing AVClass. This is 606 * useful for searching for options without needing to allocate the corresponding 607 * object. 608 */ 609 #define AV_OPT_SEARCH_FAKE_OBJ 0x0002 610 611 /** 612 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than 613 * one component for certain option types. 614 * @see AVOptionRanges for details. 615 */ 616 #define AV_OPT_MULTI_COMPONENT_RANGE 0x1000 617 618 /** 619 * Look for an option in an object. Consider only options which 620 * have all the specified flags set. 621 * 622 * @param[in] obj A pointer to a struct whose first element is a 623 * pointer to an AVClass. 624 * Alternatively a double pointer to an AVClass, if 625 * AV_OPT_SEARCH_FAKE_OBJ search flag is set. 626 * @param[in] name The name of the option to look for. 627 * @param[in] unit When searching for named constants, name of the unit 628 * it belongs to. 629 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). 630 * @param search_flags A combination of AV_OPT_SEARCH_*. 631 * 632 * @return A pointer to the option found, or NULL if no option 633 * was found. 634 * 635 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable 636 * directly with av_opt_set(). Use special calls which take an options 637 * AVDictionary (e.g. avformat_open_input()) to set options found with this 638 * flag. 639 */ 640 const AVOption *av_opt_find(void *obj, const char *name, const char *unit, 641 int opt_flags, int search_flags); 642 643 /** 644 * Look for an option in an object. Consider only options which 645 * have all the specified flags set. 646 * 647 * @param[in] obj A pointer to a struct whose first element is a 648 * pointer to an AVClass. 649 * Alternatively a double pointer to an AVClass, if 650 * AV_OPT_SEARCH_FAKE_OBJ search flag is set. 651 * @param[in] name The name of the option to look for. 652 * @param[in] unit When searching for named constants, name of the unit 653 * it belongs to. 654 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). 655 * @param search_flags A combination of AV_OPT_SEARCH_*. 656 * @param[out] target_obj if non-NULL, an object to which the option belongs will be 657 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present 658 * in search_flags. This parameter is ignored if search_flags contain 659 * AV_OPT_SEARCH_FAKE_OBJ. 660 * 661 * @return A pointer to the option found, or NULL if no option 662 * was found. 663 */ 664 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit, 665 int opt_flags, int search_flags, void **target_obj); 666 667 /** 668 * Iterate over all AVOptions belonging to obj. 669 * 670 * @param obj an AVOptions-enabled struct or a double pointer to an 671 * AVClass describing it. 672 * @param prev result of the previous call to av_opt_next() on this object 673 * or NULL 674 * @return next AVOption or NULL 675 */ 676 const AVOption *av_opt_next(void *obj, const AVOption *prev); 677 678 /** 679 * Iterate over AVOptions-enabled children of obj. 680 * 681 * @param prev result of a previous call to this function or NULL 682 * @return next AVOptions-enabled child or NULL 683 */ 684 void *av_opt_child_next(void *obj, void *prev); 685 686 /** 687 * Iterate over potential AVOptions-enabled children of parent. 688 * 689 * @param prev result of a previous call to this function or NULL 690 * @return AVClass corresponding to next potential child or NULL 691 */ 692 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev); 693 694 /** 695 * @defgroup opt_set_funcs Option setting functions 696 * @{ 697 * Those functions set the field of obj with the given name to value. 698 * 699 * @param[in] obj A struct whose first element is a pointer to an AVClass. 700 * @param[in] name the name of the field to set 701 * @param[in] val The value to set. In case of av_opt_set() if the field is not 702 * of a string type, then the given string is parsed. 703 * SI postfixes and some named scalars are supported. 704 * If the field is of a numeric type, it has to be a numeric or named 705 * scalar. Behavior with more than one scalar and +- infix operators 706 * is undefined. 707 * If the field is of a flags type, it has to be a sequence of numeric 708 * scalars or named flags separated by '+' or '-'. Prefixing a flag 709 * with '+' causes it to be set without affecting the other flags; 710 * similarly, '-' unsets a flag. 711 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN 712 * is passed here, then the option may be set on a child of obj. 713 * 714 * @return 0 if the value has been set, or an AVERROR code in case of 715 * error: 716 * AVERROR_OPTION_NOT_FOUND if no matching option exists 717 * AVERROR(ERANGE) if the value is out of range 718 * AVERROR(EINVAL) if the value is not valid 719 */ 720 int av_opt_set (void *obj, const char *name, const char *val, int search_flags); 721 int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags); 722 int av_opt_set_double (void *obj, const char *name, double val, int search_flags); 723 int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags); 724 int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags); 725 int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags); 726 int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags); 727 int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags); 728 int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags); 729 int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags); 730 /** 731 * @note Any old dictionary present is discarded and replaced with a copy of the new one. The 732 * caller still owns val is and responsible for freeing it. 733 */ 734 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags); 735 736 /** 737 * Set a binary option to an integer list. 738 * 739 * @param obj AVClass object to set options on 740 * @param name name of the binary option 741 * @param val pointer to an integer list (must have the correct type with 742 * regard to the contents of the list) 743 * @param term list terminator (usually 0 or -1) 744 * @param flags search flags 745 */ 746 #define av_opt_set_int_list(obj, name, val, term, flags) \ 747 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \ 748 AVERROR(EINVAL) : \ 749 av_opt_set_bin(obj, name, (const uint8_t *)(val), \ 750 av_int_list_length(val, term) * sizeof(*(val)), flags)) 751 752 /** 753 * @} 754 */ 755 756 /** 757 * @defgroup opt_get_funcs Option getting functions 758 * @{ 759 * Those functions get a value of the option with the given name from an object. 760 * 761 * @param[in] obj a struct whose first element is a pointer to an AVClass. 762 * @param[in] name name of the option to get. 763 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN 764 * is passed here, then the option may be found in a child of obj. 765 * @param[out] out_val value of the option will be written here 766 * @return >=0 on success, a negative error code otherwise 767 */ 768 /** 769 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller 770 */ 771 int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val); 772 int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val); 773 int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val); 774 int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val); 775 int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out); 776 int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt); 777 int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt); 778 int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val); 779 int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout); 780 /** 781 * @param[out] out_val The returned dictionary is a copy of the actual value and must 782 * be freed with av_dict_free() by the caller 783 */ 784 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val); 785 /** 786 * @} 787 */ 788 /** 789 * Gets a pointer to the requested field in a struct. 790 * This function allows accessing a struct even when its fields are moved or 791 * renamed since the application making the access has been compiled, 792 * 793 * @returns a pointer to the field, it can be cast to the correct type and read 794 * or written to. 795 */ 796 void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name); 797 798 /** 799 * Free an AVOptionRanges struct and set it to NULL. 800 */ 801 void av_opt_freep_ranges(AVOptionRanges **ranges); 802 803 /** 804 * Get a list of allowed ranges for the given option. 805 * 806 * The returned list may depend on other fields in obj like for example profile. 807 * 808 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored 809 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance 810 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges 811 * 812 * The result must be freed with av_opt_freep_ranges. 813 * 814 * @return number of compontents returned on success, a negative errro code otherwise 815 */ 816 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags); 817 818 /** 819 * Copy options from src object into dest object. 820 * 821 * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object. 822 * Original memory allocated for such options is freed unless both src and dest options points to the same memory. 823 * 824 * @param dest Object to copy from 825 * @param src Object to copy into 826 * @return 0 on success, negative on error 827 */ 828 int av_opt_copy(void *dest, void *src); 829 830 /** 831 * Get a default list of allowed ranges for the given option. 832 * 833 * This list is constructed without using the AVClass.query_ranges() callback 834 * and can be used as fallback from within the callback. 835 * 836 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored 837 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance 838 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges 839 * 840 * The result must be freed with av_opt_free_ranges. 841 * 842 * @return number of compontents returned on success, a negative errro code otherwise 843 */ 844 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags); 845 846 /** 847 * Check if given option is set to its default value. 848 * 849 * Options o must belong to the obj. This function must not be called to check child's options state. 850 * @see av_opt_is_set_to_default_by_name(). 851 * 852 * @param obj AVClass object to check option on 853 * @param o option to be checked 854 * @return >0 when option is set to its default, 855 * 0 when option is not set its default, 856 * <0 on error 857 */ 858 int av_opt_is_set_to_default(void *obj, const AVOption *o); 859 860 /** 861 * Check if given option is set to its default value. 862 * 863 * @param obj AVClass object to check option on 864 * @param name option name 865 * @param search_flags combination of AV_OPT_SEARCH_* 866 * @return >0 when option is set to its default, 867 * 0 when option is not set its default, 868 * <0 on error 869 */ 870 int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags); 871 872 873 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only. 874 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only. 875 876 /** 877 * Serialize object's options. 878 * 879 * Create a string containing object's serialized options. 880 * Such string may be passed back to av_opt_set_from_string() in order to restore option values. 881 * 882 * @param[in] obj AVClass object to serialize 883 * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG) 884 * @param[in] flags combination of AV_OPT_SERIALIZE_* flags 885 * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options. 886 * Buffer must be freed by the caller when is no longer needed. 887 * @param[in] key_val_sep character used to separate key from value 888 * @param[in] pairs_sep character used to separate two pairs from each other 889 * @return >= 0 on success, negative on error 890 */ 891 int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer, 892 const char key_val_sep, const char pairs_sep); 893 /** 894 * @} 895 */ 896 897 #endif /* AVUTIL_OPT_H */ 898