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 220enum 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_CONST = 128, 230 AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers 231 AV_OPT_TYPE_PIXEL_FMT = MKBETAG('P','F','M','T'), 232 AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'), 233 AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational 234 AV_OPT_TYPE_DURATION = MKBETAG('D','U','R',' '), 235 AV_OPT_TYPE_COLOR = MKBETAG('C','O','L','R'), 236 AV_OPT_TYPE_CHANNEL_LAYOUT = MKBETAG('C','H','L','A'), 237#if FF_API_OLD_AVOPTIONS 238 FF_OPT_TYPE_FLAGS = 0, 239 FF_OPT_TYPE_INT, 240 FF_OPT_TYPE_INT64, 241 FF_OPT_TYPE_DOUBLE, 242 FF_OPT_TYPE_FLOAT, 243 FF_OPT_TYPE_STRING, 244 FF_OPT_TYPE_RATIONAL, 245 FF_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length 246 FF_OPT_TYPE_CONST=128, 247#endif 248}; 249 250/** 251 * AVOption 252 */ 253typedef struct AVOption { 254 const char *name; 255 256 /** 257 * short English help text 258 * @todo What about other languages? 259 */ 260 const char *help; 261 262 /** 263 * The offset relative to the context structure where the option 264 * value is stored. It should be 0 for named constants. 265 */ 266 int offset; 267 enum AVOptionType type; 268 269 /** 270 * the default value for scalar options 271 */ 272 union { 273 int64_t i64; 274 double dbl; 275 const char *str; 276 /* TODO those are unused now */ 277 AVRational q; 278 } default_val; 279 double min; ///< minimum valid value for the option 280 double max; ///< maximum valid value for the option 281 282 int flags; 283#define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding 284#define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding 285#if FF_API_OPT_TYPE_METADATA 286#define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ... 287#endif 288#define AV_OPT_FLAG_AUDIO_PARAM 8 289#define AV_OPT_FLAG_VIDEO_PARAM 16 290#define AV_OPT_FLAG_SUBTITLE_PARAM 32 291/** 292 * The option is inteded for exporting values to the caller. 293 */ 294#define AV_OPT_FLAG_EXPORT 64 295/** 296 * The option may not be set through the AVOptions API, only read. 297 * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set. 298 */ 299#define AV_OPT_FLAG_READONLY 128 300#define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering 301//FIXME think about enc-audio, ... style flags 302 303 /** 304 * The logical unit to which the option belongs. Non-constant 305 * options and corresponding named constants share the same 306 * unit. May be NULL. 307 */ 308 const char *unit; 309} AVOption; 310 311/** 312 * A single allowed range of values, or a single allowed value. 313 */ 314typedef struct AVOptionRange { 315 const char *str; 316 /** 317 * Value range. 318 * For string ranges this represents the min/max length. 319 * For dimensions this represents the min/max pixel count or width/height in multi-component case. 320 */ 321 double value_min, value_max; 322 /** 323 * Value's component range. 324 * For string this represents the unicode range for chars, 0-127 limits to ASCII. 325 */ 326 double component_min, component_max; 327 /** 328 * Range flag. 329 * If set to 1 the struct encodes a range, if set to 0 a single value. 330 */ 331 int is_range; 332} AVOptionRange; 333 334/** 335 * List of AVOptionRange structs. 336 */ 337typedef struct AVOptionRanges { 338 /** 339 * Array of option ranges. 340 * 341 * Most of option types use just one component. 342 * Following describes multi-component option types: 343 * 344 * AV_OPT_TYPE_IMAGE_SIZE: 345 * component index 0: range of pixel count (width * height). 346 * component index 1: range of width. 347 * component index 2: range of height. 348 * 349 * @note To obtain multi-component version of this structure, user must 350 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or 351 * av_opt_query_ranges_default function. 352 * 353 * Multi-component range can be read as in following example: 354 * 355 * @code 356 * int range_index, component_index; 357 * AVOptionRanges *ranges; 358 * AVOptionRange *range[3]; //may require more than 3 in the future. 359 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE); 360 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) { 361 * for (component_index = 0; component_index < ranges->nb_components; component_index++) 362 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index]; 363 * //do something with range here. 364 * } 365 * av_opt_freep_ranges(&ranges); 366 * @endcode 367 */ 368 AVOptionRange **range; 369 /** 370 * Number of ranges per component. 371 */ 372 int nb_ranges; 373 /** 374 * Number of componentes. 375 */ 376 int nb_components; 377} AVOptionRanges; 378 379 380#if FF_API_FIND_OPT 381/** 382 * Look for an option in obj. Look only for the options which 383 * have the flags set as specified in mask and flags (that is, 384 * for which it is the case that (opt->flags & mask) == flags). 385 * 386 * @param[in] obj a pointer to a struct whose first element is a 387 * pointer to an AVClass 388 * @param[in] name the name of the option to look for 389 * @param[in] unit the unit of the option to look for, or any if NULL 390 * @return a pointer to the option found, or NULL if no option 391 * has been found 392 * 393 * @deprecated use av_opt_find. 394 */ 395attribute_deprecated 396const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags); 397#endif 398 399#if FF_API_OLD_AVOPTIONS 400/** 401 * Set the field of obj with the given name to value. 402 * 403 * @param[in] obj A struct whose first element is a pointer to an 404 * AVClass. 405 * @param[in] name the name of the field to set 406 * @param[in] val The value to set. If the field is not of a string 407 * type, then the given string is parsed. 408 * SI postfixes and some named scalars are supported. 409 * If the field is of a numeric type, it has to be a numeric or named 410 * scalar. Behavior with more than one scalar and +- infix operators 411 * is undefined. 412 * If the field is of a flags type, it has to be a sequence of numeric 413 * scalars or named flags separated by '+' or '-'. Prefixing a flag 414 * with '+' causes it to be set without affecting the other flags; 415 * similarly, '-' unsets a flag. 416 * @param[out] o_out if non-NULL put here a pointer to the AVOption 417 * found 418 * @param alloc this parameter is currently ignored 419 * @return 0 if the value has been set, or an AVERROR code in case of 420 * error: 421 * AVERROR_OPTION_NOT_FOUND if no matching option exists 422 * AVERROR(ERANGE) if the value is out of range 423 * AVERROR(EINVAL) if the value is not valid 424 * @deprecated use av_opt_set() 425 */ 426attribute_deprecated 427int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out); 428 429attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n); 430attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n); 431attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n); 432 433double av_get_double(void *obj, const char *name, const AVOption **o_out); 434AVRational av_get_q(void *obj, const char *name, const AVOption **o_out); 435int64_t av_get_int(void *obj, const char *name, const AVOption **o_out); 436attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len); 437attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last); 438#endif 439 440/** 441 * Show the obj options. 442 * 443 * @param req_flags requested flags for the options to show. Show only the 444 * options for which it is opt->flags & req_flags. 445 * @param rej_flags rejected flags for the options to show. Show only the 446 * options for which it is !(opt->flags & req_flags). 447 * @param av_log_obj log context to use for showing the options 448 */ 449int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags); 450 451/** 452 * Set the values of all AVOption fields to their default values. 453 * 454 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) 455 */ 456void av_opt_set_defaults(void *s); 457 458#if FF_API_OLD_AVOPTIONS 459attribute_deprecated 460void av_opt_set_defaults2(void *s, int mask, int flags); 461#endif 462 463/** 464 * Parse the key/value pairs list in opts. For each key/value pair 465 * found, stores the value in the field in ctx that is named like the 466 * key. ctx must be an AVClass context, storing is done using 467 * AVOptions. 468 * 469 * @param opts options string to parse, may be NULL 470 * @param key_val_sep a 0-terminated list of characters used to 471 * separate key from value 472 * @param pairs_sep a 0-terminated list of characters used to separate 473 * two pairs from each other 474 * @return the number of successfully set key/value pairs, or a negative 475 * value corresponding to an AVERROR code in case of error: 476 * AVERROR(EINVAL) if opts cannot be parsed, 477 * the error code issued by av_set_string3() if a key/value pair 478 * cannot be set 479 */ 480int av_set_options_string(void *ctx, const char *opts, 481 const char *key_val_sep, const char *pairs_sep); 482 483/** 484 * Parse the key-value pairs list in opts. For each key=value pair found, 485 * set the value of the corresponding option in ctx. 486 * 487 * @param ctx the AVClass object to set options on 488 * @param opts the options string, key-value pairs separated by a 489 * delimiter 490 * @param shorthand a NULL-terminated array of options names for shorthand 491 * notation: if the first field in opts has no key part, 492 * the key is taken from the first element of shorthand; 493 * then again for the second, etc., until either opts is 494 * finished, shorthand is finished or a named option is 495 * found; after that, all options must be named 496 * @param key_val_sep a 0-terminated list of characters used to separate 497 * key from value, for example '=' 498 * @param pairs_sep a 0-terminated list of characters used to separate 499 * two pairs from each other, for example ':' or ',' 500 * @return the number of successfully set key=value pairs, or a negative 501 * value corresponding to an AVERROR code in case of error: 502 * AVERROR(EINVAL) if opts cannot be parsed, 503 * the error code issued by av_set_string3() if a key/value pair 504 * cannot be set 505 * 506 * Options names must use only the following characters: a-z A-Z 0-9 - . / _ 507 * Separators must use characters distinct from option names and from each 508 * other. 509 */ 510int av_opt_set_from_string(void *ctx, const char *opts, 511 const char *const *shorthand, 512 const char *key_val_sep, const char *pairs_sep); 513/** 514 * Free all string and binary options in obj. 515 */ 516void av_opt_free(void *obj); 517 518/** 519 * Check whether a particular flag is set in a flags field. 520 * 521 * @param field_name the name of the flag field option 522 * @param flag_name the name of the flag to check 523 * @return non-zero if the flag is set, zero if the flag isn't set, 524 * isn't of the right type, or the flags field doesn't exist. 525 */ 526int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name); 527 528/** 529 * Set all the options from a given dictionary on an object. 530 * 531 * @param obj a struct whose first element is a pointer to AVClass 532 * @param options options to process. This dictionary will be freed and replaced 533 * by a new one containing all options not found in obj. 534 * Of course this new dictionary needs to be freed by caller 535 * with av_dict_free(). 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 */ 542int av_opt_set_dict(void *obj, struct AVDictionary **options); 543 544 545/** 546 * Set all the options from a given dictionary on an object. 547 * 548 * @param obj a struct whose first element is a pointer to AVClass 549 * @param options options to process. This dictionary will be freed and replaced 550 * by a new one containing all options not found in obj. 551 * Of course this new dictionary needs to be freed by caller 552 * with av_dict_free(). 553 * @param search_flags A combination of AV_OPT_SEARCH_*. 554 * 555 * @return 0 on success, a negative AVERROR if some option was found in obj, 556 * but could not be set. 557 * 558 * @see av_dict_copy() 559 */ 560int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags); 561 562/** 563 * Extract a key-value pair from the beginning of a string. 564 * 565 * @param ropts pointer to the options string, will be updated to 566 * point to the rest of the string (one of the pairs_sep 567 * or the final NUL) 568 * @param key_val_sep a 0-terminated list of characters used to separate 569 * key from value, for example '=' 570 * @param pairs_sep a 0-terminated list of characters used to separate 571 * two pairs from each other, for example ':' or ',' 572 * @param flags flags; see the AV_OPT_FLAG_* values below 573 * @param rkey parsed key; must be freed using av_free() 574 * @param rval parsed value; must be freed using av_free() 575 * 576 * @return >=0 for success, or a negative value corresponding to an 577 * AVERROR code in case of error; in particular: 578 * AVERROR(EINVAL) if no key is present 579 * 580 */ 581int av_opt_get_key_value(const char **ropts, 582 const char *key_val_sep, const char *pairs_sep, 583 unsigned flags, 584 char **rkey, char **rval); 585 586enum { 587 588 /** 589 * Accept to parse a value without a key; the key will then be returned 590 * as NULL. 591 */ 592 AV_OPT_FLAG_IMPLICIT_KEY = 1, 593}; 594 595/** 596 * @defgroup opt_eval_funcs Evaluating option strings 597 * @{ 598 * This group of functions can be used to evaluate option strings 599 * and get numbers out of them. They do the same thing as av_opt_set(), 600 * except the result is written into the caller-supplied pointer. 601 * 602 * @param obj a struct whose first element is a pointer to AVClass. 603 * @param o an option for which the string is to be evaluated. 604 * @param val string to be evaluated. 605 * @param *_out value of the string will be written here. 606 * 607 * @return 0 on success, a negative number on failure. 608 */ 609int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out); 610int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out); 611int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out); 612int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out); 613int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out); 614int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out); 615/** 616 * @} 617 */ 618 619#define AV_OPT_SEARCH_CHILDREN 0x0001 /**< Search in possible children of the 620 given object first. */ 621/** 622 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass 623 * instead of a required pointer to a struct containing AVClass. This is 624 * useful for searching for options without needing to allocate the corresponding 625 * object. 626 */ 627#define AV_OPT_SEARCH_FAKE_OBJ 0x0002 628 629/** 630 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than 631 * one component for certain option types. 632 * @see AVOptionRanges for details. 633 */ 634#define AV_OPT_MULTI_COMPONENT_RANGE 0x1000 635 636/** 637 * Look for an option in an object. Consider only options which 638 * have all the specified flags set. 639 * 640 * @param[in] obj A pointer to a struct whose first element is a 641 * pointer to an AVClass. 642 * Alternatively a double pointer to an AVClass, if 643 * AV_OPT_SEARCH_FAKE_OBJ search flag is set. 644 * @param[in] name The name of the option to look for. 645 * @param[in] unit When searching for named constants, name of the unit 646 * it belongs to. 647 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). 648 * @param search_flags A combination of AV_OPT_SEARCH_*. 649 * 650 * @return A pointer to the option found, or NULL if no option 651 * was found. 652 * 653 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable 654 * directly with av_set_string3(). Use special calls which take an options 655 * AVDictionary (e.g. avformat_open_input()) to set options found with this 656 * flag. 657 */ 658const AVOption *av_opt_find(void *obj, const char *name, const char *unit, 659 int opt_flags, int search_flags); 660 661/** 662 * Look for an option in an object. Consider only options which 663 * have all the specified flags set. 664 * 665 * @param[in] obj A pointer to a struct whose first element is a 666 * pointer to an AVClass. 667 * Alternatively a double pointer to an AVClass, if 668 * AV_OPT_SEARCH_FAKE_OBJ search flag is set. 669 * @param[in] name The name of the option to look for. 670 * @param[in] unit When searching for named constants, name of the unit 671 * it belongs to. 672 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). 673 * @param search_flags A combination of AV_OPT_SEARCH_*. 674 * @param[out] target_obj if non-NULL, an object to which the option belongs will be 675 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present 676 * in search_flags. This parameter is ignored if search_flags contain 677 * AV_OPT_SEARCH_FAKE_OBJ. 678 * 679 * @return A pointer to the option found, or NULL if no option 680 * was found. 681 */ 682const AVOption *av_opt_find2(void *obj, const char *name, const char *unit, 683 int opt_flags, int search_flags, void **target_obj); 684 685/** 686 * Iterate over all AVOptions belonging to obj. 687 * 688 * @param obj an AVOptions-enabled struct or a double pointer to an 689 * AVClass describing it. 690 * @param prev result of the previous call to av_opt_next() on this object 691 * or NULL 692 * @return next AVOption or NULL 693 */ 694const AVOption *av_opt_next(void *obj, const AVOption *prev); 695 696/** 697 * Iterate over AVOptions-enabled children of obj. 698 * 699 * @param prev result of a previous call to this function or NULL 700 * @return next AVOptions-enabled child or NULL 701 */ 702void *av_opt_child_next(void *obj, void *prev); 703 704/** 705 * Iterate over potential AVOptions-enabled children of parent. 706 * 707 * @param prev result of a previous call to this function or NULL 708 * @return AVClass corresponding to next potential child or NULL 709 */ 710const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev); 711 712/** 713 * @defgroup opt_set_funcs Option setting functions 714 * @{ 715 * Those functions set the field of obj with the given name to value. 716 * 717 * @param[in] obj A struct whose first element is a pointer to an AVClass. 718 * @param[in] name the name of the field to set 719 * @param[in] val The value to set. In case of av_opt_set() if the field is not 720 * of a string type, then the given string is parsed. 721 * SI postfixes and some named scalars are supported. 722 * If the field is of a numeric type, it has to be a numeric or named 723 * scalar. Behavior with more than one scalar and +- infix operators 724 * is undefined. 725 * If the field is of a flags type, it has to be a sequence of numeric 726 * scalars or named flags separated by '+' or '-'. Prefixing a flag 727 * with '+' causes it to be set without affecting the other flags; 728 * similarly, '-' unsets a flag. 729 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN 730 * is passed here, then the option may be set on a child of obj. 731 * 732 * @return 0 if the value has been set, or an AVERROR code in case of 733 * error: 734 * AVERROR_OPTION_NOT_FOUND if no matching option exists 735 * AVERROR(ERANGE) if the value is out of range 736 * AVERROR(EINVAL) if the value is not valid 737 */ 738int av_opt_set (void *obj, const char *name, const char *val, int search_flags); 739int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags); 740int av_opt_set_double(void *obj, const char *name, double val, int search_flags); 741int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags); 742int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags); 743int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags); 744int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags); 745int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags); 746int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags); 747int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags); 748 749/** 750 * Set a binary option to an integer list. 751 * 752 * @param obj AVClass object to set options on 753 * @param name name of the binary option 754 * @param val pointer to an integer list (must have the correct type with 755 * regard to the contents of the list) 756 * @param term list terminator (usually 0 or -1) 757 * @param flags search flags 758 */ 759#define av_opt_set_int_list(obj, name, val, term, flags) \ 760 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \ 761 AVERROR(EINVAL) : \ 762 av_opt_set_bin(obj, name, (const uint8_t *)(val), \ 763 av_int_list_length(val, term) * sizeof(*(val)), flags)) 764/** 765 * @} 766 */ 767 768/** 769 * @defgroup opt_get_funcs Option getting functions 770 * @{ 771 * Those functions get a value of the option with the given name from an object. 772 * 773 * @param[in] obj a struct whose first element is a pointer to an AVClass. 774 * @param[in] name name of the option to get. 775 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN 776 * is passed here, then the option may be found in a child of obj. 777 * @param[out] out_val value of the option will be written here 778 * @return >=0 on success, a negative error code otherwise 779 */ 780/** 781 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller 782 */ 783int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val); 784int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val); 785int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val); 786int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val); 787int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out); 788int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt); 789int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt); 790int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val); 791int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout); 792/** 793 * @} 794 */ 795/** 796 * Gets a pointer to the requested field in a struct. 797 * This function allows accessing a struct even when its fields are moved or 798 * renamed since the application making the access has been compiled, 799 * 800 * @returns a pointer to the field, it can be cast to the correct type and read 801 * or written to. 802 */ 803void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name); 804 805/** 806 * Free an AVOptionRanges struct and set it to NULL. 807 */ 808void av_opt_freep_ranges(AVOptionRanges **ranges); 809 810/** 811 * Get a list of allowed ranges for the given option. 812 * 813 * The returned list may depend on other fields in obj like for example profile. 814 * 815 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored 816 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance 817 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges 818 * 819 * The result must be freed with av_opt_freep_ranges. 820 * 821 * @return number of compontents returned on success, a negative errro code otherwise 822 */ 823int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags); 824 825int av_opt_copy(void *dest, void *src); 826 827/** 828 * Get a default list of allowed ranges for the given option. 829 * 830 * This list is constructed without using the AVClass.query_ranges() callback 831 * and can be used as fallback from within the callback. 832 * 833 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored 834 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance 835 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges 836 * 837 * The result must be freed with av_opt_free_ranges. 838 * 839 * @return number of compontents returned on success, a negative errro code otherwise 840 */ 841int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags); 842 843/** 844 * @} 845 */ 846 847#endif /* AVUTIL_OPT_H */ 848