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
37
38 /**
39 * @defgroup avoptions AVOptions
40 * @ingroup lavu_data
41 * @{
42 * AVOptions provide a generic system to declare options on arbitrary structs
43 * ("objects"). An option can have a help text, a type and a range of possible
44 * values. Options may then be enumerated, read and written to.
45 *
46 * @section avoptions_implement Implementing AVOptions
47 * This section describes how to add AVOptions capabilities to a struct.
48 *
49 * All AVOptions-related information is stored in an AVClass. Therefore
50 * the first member of the struct should be a pointer to an AVClass describing it.
51 * The option field of the AVClass must be set to a NULL-terminated static array
52 * of AVOptions. Each AVOption must have a non-empty name, a type, a default
53 * value and for number-type AVOptions also a range of allowed values. It must
54 * also declare an offset in bytes from the start of the struct, where the field
55 * associated with this AVOption is located. Other fields in the AVOption struct
56 * should also be set when applicable, but are not required.
57 *
58 * The following example illustrates an AVOptions-enabled struct:
59 * @code
60 * typedef struct test_struct {
61 * const AVClass *class;
62 * int int_opt;
63 * char *str_opt;
64 * uint8_t *bin_opt;
65 * int bin_len;
66 * } test_struct;
67 *
68 * static const AVOption test_options[] = {
69 * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
70 * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
71 * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
72 * AV_OPT_TYPE_STRING },
73 * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
74 * AV_OPT_TYPE_BINARY },
75 * { NULL },
76 * };
77 *
78 * static const AVClass test_class = {
79 * .class_name = "test class",
80 * .item_name = av_default_item_name,
81 * .option = test_options,
82 * .version = LIBAVUTIL_VERSION_INT,
83 * };
84 * @endcode
85 *
86 * Next, when allocating your struct, you must ensure that the AVClass pointer
87 * is set to the correct value. Then, av_opt_set_defaults() can be called to
88 * initialize defaults. After that the struct is ready to be used with the
89 * AVOptions API.
90 *
91 * When cleaning up, you may use the av_opt_free() function to automatically
92 * free all the allocated string and binary options.
93 *
94 * Continuing with the above example:
95 *
96 * @code
97 * test_struct *alloc_test_struct(void)
98 * {
99 * test_struct *ret = av_mallocz(sizeof(*ret));
100 * ret->class = &test_class;
101 * av_opt_set_defaults(ret);
102 * return ret;
103 * }
104 * void free_test_struct(test_struct **foo)
105 * {
106 * av_opt_free(*foo);
107 * av_freep(foo);
108 * }
109 * @endcode
110 *
111 * @subsection avoptions_implement_nesting Nesting
112 * It may happen that an AVOptions-enabled struct contains another
113 * AVOptions-enabled struct as a member (e.g. AVCodecContext in
114 * libavcodec exports generic options, while its priv_data field exports
115 * codec-specific options). In such a case, it is possible to set up the
116 * parent struct to export a child's options. To do that, simply
117 * implement AVClass.child_next() and AVClass.child_class_next() in the
118 * parent struct's AVClass.
119 * Assuming that the test_struct from above now also contains a
120 * child_struct field:
121 *
122 * @code
123 * typedef struct child_struct {
124 * AVClass *class;
125 * int flags_opt;
126 * } child_struct;
127 * static const AVOption child_opts[] = {
128 * { "test_flags", "This is a test option of flags type.",
129 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
130 * { NULL },
131 * };
132 * static const AVClass child_class = {
133 * .class_name = "child class",
134 * .item_name = av_default_item_name,
135 * .option = child_opts,
136 * .version = LIBAVUTIL_VERSION_INT,
137 * };
138 *
139 * void *child_next(void *obj, void *prev)
140 * {
141 * test_struct *t = obj;
142 * if (!prev && t->child_struct)
143 * return t->child_struct;
144 * return NULL
145 * }
146 * const AVClass child_class_next(const AVClass *prev)
147 * {
148 * return prev ? NULL : &child_class;
149 * }
150 * @endcode
151 * Putting child_next() and child_class_next() as defined above into
152 * test_class will now make child_struct's options accessible through
153 * test_struct (again, proper setup as described above needs to be done on
154 * child_struct right after it is created).
155 *
156 * From the above example it might not be clear why both child_next()
157 * and child_class_next() are needed. The distinction is that child_next()
158 * iterates over actually existing objects, while child_class_next()
159 * iterates over all possible child classes. E.g. if an AVCodecContext
160 * was initialized to use a codec which has private options, then its
161 * child_next() will return AVCodecContext.priv_data and finish
162 * iterating. OTOH child_class_next() on AVCodecContext.av_class will
163 * iterate over all available codecs with private options.
164 *
165 * @subsection avoptions_implement_named_constants Named constants
166 * It is possible to create named constants for options. Simply set the unit
167 * field of the option the constants should apply to a string and
168 * create the constants themselves as options of type AV_OPT_TYPE_CONST
169 * with their unit field set to the same string.
170 * Their default_val field should contain the value of the named
171 * constant.
172 * For example, to add some named constants for the test_flags option
173 * above, put the following into the child_opts array:
174 * @code
175 * { "test_flags", "This is a test option of flags type.",
176 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
177 * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
178 * @endcode
179 *
180 * @section avoptions_use Using AVOptions
181 * This section deals with accessing options in an AVOptions-enabled struct.
182 * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
183 * AVFormatContext in libavformat.
184 *
185 * @subsection avoptions_use_examine Examining AVOptions
186 * The basic functions for examining options are av_opt_next(), which iterates
187 * over all options defined for one object, and av_opt_find(), which searches
188 * for an option with the given name.
189 *
190 * The situation is more complicated with nesting. An AVOptions-enabled struct
191 * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
192 * to av_opt_find() will make the function search children recursively.
193 *
194 * For enumerating there are basically two cases. The first is when you want to
195 * get all options that may potentially exist on the struct and its children
196 * (e.g. when constructing documentation). In that case you should call
197 * av_opt_child_class_next() recursively on the parent struct's AVClass. The
198 * second case is when you have an already initialized struct with all its
199 * children and you want to get all options that can be actually written or read
200 * from it. In that case you should call av_opt_child_next() recursively (and
201 * av_opt_next() on each result).
202 *
203 * @subsection avoptions_use_get_set Reading and writing AVOptions
204 * When setting options, you often have a string read directly from the
205 * user. In such a case, simply passing it to av_opt_set() is enough. For
206 * non-string type options, av_opt_set() will parse the string according to the
207 * option type.
208 *
209 * Similarly av_opt_get() will read any option type and convert it to a string
210 * which will be returned. Do not forget that the string is allocated, so you
211 * have to free it with av_free().
212 *
213 * In some cases it may be more convenient to put all options into an
214 * AVDictionary and call av_opt_set_dict() on it. A specific case of this
215 * are the format/codec open functions in lavf/lavc which take a dictionary
216 * filled with option as a parameter. This makes it possible to set some options
217 * that cannot be set otherwise, since e.g. the input file format is not known
218 * before the file is actually opened.
219 */
220
229 AV_OPT_TYPE_BINARY,
///< offset must point to a pointer immediately followed by an int for the length
241 };
242
243 /**
244 * AVOption
245 */
248
249 /**
250 * short English help text
251 * @todo What about other languages?
252 */
254
255 /**
256 * The offset relative to the context structure where the option
257 * value is stored. It should be 0 for named constants.
258 */
261
262 /**
263 * the default value for scalar options
264 */
265 union {
269 /* TODO those are unused now */
272 double min;
///< minimum valid value for the option
273 double max;
///< maximum valid value for the option
274
276 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
277 #define AV_OPT_FLAG_DECODING_PARAM 2
///< a generic parameter which can be set by the user for demuxing or decoding
278 #define AV_OPT_FLAG_AUDIO_PARAM 8
279 #define AV_OPT_FLAG_VIDEO_PARAM 16
280 #define AV_OPT_FLAG_SUBTITLE_PARAM 32
281 /**
282 * The option is intended for exporting values to the caller.
283 */
284 #define AV_OPT_FLAG_EXPORT 64
285 /**
286 * The option may not be set through the AVOptions API, only read.
287 * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
288 */
289 #define AV_OPT_FLAG_READONLY 128
290 #define AV_OPT_FLAG_BSF_PARAM (1<<8) ///< a generic parameter which can be set by the user for bit stream filtering
291 #define AV_OPT_FLAG_FILTERING_PARAM (1<<16)
///< a generic parameter which can be set by the user for filtering
292 //FIXME think about enc-audio, ... style flags
293
294 /**
295 * The logical unit to which the option belongs. Non-constant
296 * options and corresponding named constants share the same
297 * unit. May be NULL.
298 */
301
302 /**
303 * A single allowed range of values, or a single allowed value.
304 */
307 /**
308 * Value range.
309 * For string ranges this represents the min/max length.
310 * For dimensions this represents the min/max pixel count or width/height in multi-component case.
311 */
313 /**
314 * Value's component range.
315 * For string this represents the unicode range for chars, 0-127 limits to ASCII.
316 */
318 /**
319 * Range flag.
320 * If set to 1 the struct encodes a range, if set to 0 a single value.
321 */
324
325 /**
326 * List of AVOptionRange structs.
327 */
329 /**
330 * Array of option ranges.
331 *
332 * Most of option types use just one component.
333 * Following describes multi-component option types:
334 *
335 * AV_OPT_TYPE_IMAGE_SIZE:
336 * component index 0: range of pixel count (width * height).
337 * component index 1: range of width.
338 * component index 2: range of height.
339 *
340 * @note To obtain multi-component version of this structure, user must
341 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
342 * av_opt_query_ranges_default function.
343 *
344 * Multi-component range can be read as in following example:
345 *
346 * @code
347 * int range_index, component_index;
348 * AVOptionRanges *ranges;
349 * AVOptionRange *range[3]; //may require more than 3 in the future.
350 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
351 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
352 * for (component_index = 0; component_index < ranges->nb_components; component_index++)
353 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
354 * //do something with range here.
355 * }
356 * av_opt_freep_ranges(&ranges);
357 * @endcode
358 */
360 /**
361 * Number of ranges per component.
362 */
364 /**
365 * Number of componentes.
366 */
369
370 /**
371 * Show the obj options.
372 *
373 * @param req_flags requested flags for the options to show. Show only the
374 * options for which it is opt->flags & req_flags.
375 * @param rej_flags rejected flags for the options to show. Show only the
376 * options for which it is !(opt->flags & req_flags).
377 * @param av_log_obj log context to use for showing the options
378 */
379 int av_opt_show2(
void *obj,
void *av_log_obj,
int req_flags,
int rej_flags);
380
381 /**
382 * Set the values of all AVOption fields to their default values.
383 *
384 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
385 */
387
388 /**
389 * Set the values of all AVOption fields to their default values. Only these
390 * AVOption fields for which (opt->flags & mask) == flags will have their
391 * default applied to s.
392 *
393 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
394 * @param mask combination of AV_OPT_FLAG_*
395 * @param flags combination of AV_OPT_FLAG_*
396 */
398
399 /**
400 * Parse the key/value pairs list in opts. For each key/value pair
401 * found, stores the value in the field in ctx that is named like the
402 * key. ctx must be an AVClass context, storing is done using
403 * AVOptions.
404 *
405 * @param opts options string to parse, may be NULL
406 * @param key_val_sep a 0-terminated list of characters used to
407 * separate key from value
408 * @param pairs_sep a 0-terminated list of characters used to separate
409 * two pairs from each other
410 * @return the number of successfully set key/value pairs, or a negative
411 * value corresponding to an AVERROR code in case of error:
412 * AVERROR(EINVAL) if opts cannot be parsed,
413 * the error code issued by av_opt_set() if a key/value pair
414 * cannot be set
415 */
417 const char *key_val_sep, const char *pairs_sep);
418
419 /**
420 * Parse the key-value pairs list in opts. For each key=value pair found,
421 * set the value of the corresponding option in ctx.
422 *
423 * @param ctx the AVClass object to set options on
424 * @param opts the options string, key-value pairs separated by a
425 * delimiter
426 * @param shorthand a NULL-terminated array of options names for shorthand
427 * notation: if the first field in opts has no key part,
428 * the key is taken from the first element of shorthand;
429 * then again for the second, etc., until either opts is
430 * finished, shorthand is finished or a named option is
431 * found; after that, all options must be named
432 * @param key_val_sep a 0-terminated list of characters used to separate
433 * key from value, for example '='
434 * @param pairs_sep a 0-terminated list of characters used to separate
435 * two pairs from each other, for example ':' or ','
436 * @return the number of successfully set key=value pairs, or a negative
437 * value corresponding to an AVERROR code in case of error:
438 * AVERROR(EINVAL) if opts cannot be parsed,
439 * the error code issued by av_set_string3() if a key/value pair
440 * cannot be set
441 *
442 * Options names must use only the following characters: a-z A-Z 0-9 - . / _
443 * Separators must use characters distinct from option names and from each
444 * other.
445 */
447 const char *const *shorthand,
448 const char *key_val_sep, const char *pairs_sep);
449 /**
450 * Free all allocated objects in obj.
451 */
453
454 /**
455 * Check whether a particular flag is set in a flags field.
456 *
457 * @param field_name the name of the flag field option
458 * @param flag_name the name of the flag to check
459 * @return non-zero if the flag is set, zero if the flag isn't set,
460 * isn't of the right type, or the flags field doesn't exist.
461 */
463
464 /**
465 * Set all the options from a given dictionary on an object.
466 *
467 * @param obj a struct whose first element is a pointer to AVClass
468 * @param options options to process. This dictionary will be freed and replaced
469 * by a new one containing all options not found in obj.
470 * Of course this new dictionary needs to be freed by caller
471 * with av_dict_free().
472 *
473 * @return 0 on success, a negative AVERROR if some option was found in obj,
474 * but could not be set.
475 *
476 * @see av_dict_copy()
477 */
479
480
481 /**
482 * Set all the options from a given dictionary on an object.
483 *
484 * @param obj a struct whose first element is a pointer to AVClass
485 * @param options options to process. This dictionary will be freed and replaced
486 * by a new one containing all options not found in obj.
487 * Of course this new dictionary needs to be freed by caller
488 * with av_dict_free().
489 * @param search_flags A combination of AV_OPT_SEARCH_*.
490 *
491 * @return 0 on success, a negative AVERROR if some option was found in obj,
492 * but could not be set.
493 *
494 * @see av_dict_copy()
495 */
497
498 /**
499 * Extract a key-value pair from the beginning of a string.
500 *
501 * @param ropts pointer to the options string, will be updated to
502 * point to the rest of the string (one of the pairs_sep
503 * or the final NUL)
504 * @param key_val_sep a 0-terminated list of characters used to separate
505 * key from value, for example '='
506 * @param pairs_sep a 0-terminated list of characters used to separate
507 * two pairs from each other, for example ':' or ','
508 * @param flags flags; see the AV_OPT_FLAG_* values below
509 * @param rkey parsed key; must be freed using av_free()
510 * @param rval parsed value; must be freed using av_free()
511 *
512 * @return >=0 for success, or a negative value corresponding to an
513 * AVERROR code in case of error; in particular:
514 * AVERROR(EINVAL) if no key is present
515 *
516 */
518 const char *key_val_sep, const char *pairs_sep,
520 char **rkey, char **rval);
521
522 enum {
523
524 /**
525 * Accept to parse a value without a key; the key will then be returned
526 * as NULL.
527 */
529 };
530
531 /**
532 * @defgroup opt_eval_funcs Evaluating option strings
533 * @{
534 * This group of functions can be used to evaluate option strings
535 * and get numbers out of them. They do the same thing as av_opt_set(),
536 * except the result is written into the caller-supplied pointer.
537 *
538 * @param obj a struct whose first element is a pointer to AVClass.
539 * @param o an option for which the string is to be evaluated.
540 * @param val string to be evaluated.
541 * @param *_out value of the string will be written here.
542 *
543 * @return 0 on success, a negative number on failure.
544 */
551 /**
552 * @}
553 */
554
555 #define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
556 given object first. */
557 /**
558 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
559 * instead of a required pointer to a struct containing AVClass. This is
560 * useful for searching for options without needing to allocate the corresponding
561 * object.
562 */
563 #define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
565 /**
566 * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
567 * rather than returning an empty string.
568 */
569 #define AV_OPT_ALLOW_NULL (1 << 2)
571 /**
572 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
573 * one component for certain option types.
574 * @see AVOptionRanges for details.
575 */
576 #define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
578 /**
579 * Look for an option in an object. Consider only options which
580 * have all the specified flags set.
581 *
582 * @param[in] obj A pointer to a struct whose first element is a
583 * pointer to an AVClass.
584 * Alternatively a double pointer to an AVClass, if
585 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
586 * @param[in] name The name of the option to look for.
587 * @param[in] unit When searching for named constants, name of the unit
588 * it belongs to.
589 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
590 * @param search_flags A combination of AV_OPT_SEARCH_*.
591 *
592 * @return A pointer to the option found, or NULL if no option
593 * was found.
594 *
595 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
596 * directly with av_opt_set(). Use special calls which take an options
597 * AVDictionary (e.g. avformat_open_input()) to set options found with this
598 * flag.
599 */
601 int opt_flags, int search_flags);
602
603 /**
604 * Look for an option in an object. Consider only options which
605 * have all the specified flags set.
606 *
607 * @param[in] obj A pointer to a struct whose first element is a
608 * pointer to an AVClass.
609 * Alternatively a double pointer to an AVClass, if
610 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
611 * @param[in] name The name of the option to look for.
612 * @param[in] unit When searching for named constants, name of the unit
613 * it belongs to.
614 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
615 * @param search_flags A combination of AV_OPT_SEARCH_*.
616 * @param[out] target_obj if non-NULL, an object to which the option belongs will be
617 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
618 * in search_flags. This parameter is ignored if search_flags contain
619 * AV_OPT_SEARCH_FAKE_OBJ.
620 *
621 * @return A pointer to the option found, or NULL if no option
622 * was found.
623 */
625 int opt_flags, int search_flags, void **target_obj);
626
627 /**
628 * Iterate over all AVOptions belonging to obj.
629 *
630 * @param obj an AVOptions-enabled struct or a double pointer to an
631 * AVClass describing it.
632 * @param prev result of the previous call to av_opt_next() on this object
633 * or NULL
634 * @return next AVOption or NULL
635 */
637
638 /**
639 * Iterate over AVOptions-enabled children of obj.
640 *
641 * @param prev result of a previous call to this function or NULL
642 * @return next AVOptions-enabled child or NULL
643 */
645
646 /**
647 * Iterate over potential AVOptions-enabled children of parent.
648 *
649 * @param prev result of a previous call to this function or NULL
650 * @return AVClass corresponding to next potential child or NULL
651 */
653
654 /**
655 * @defgroup opt_set_funcs Option setting functions
656 * @{
657 * Those functions set the field of obj with the given name to value.
658 *
659 * @param[in] obj A struct whose first element is a pointer to an AVClass.
660 * @param[in] name the name of the field to set
661 * @param[in] val The value to set. In case of av_opt_set() if the field is not
662 * of a string type, then the given string is parsed.
663 * SI postfixes and some named scalars are supported.
664 * If the field is of a numeric type, it has to be a numeric or named
665 * scalar. Behavior with more than one scalar and +- infix operators
666 * is undefined.
667 * If the field is of a flags type, it has to be a sequence of numeric
668 * scalars or named flags separated by '+' or '-'. Prefixing a flag
669 * with '+' causes it to be set without affecting the other flags;
670 * similarly, '-' unsets a flag.
671 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
672 * is passed here, then the option may be set on a child of obj.
673 *
674 * @return 0 if the value has been set, or an AVERROR code in case of
675 * error:
676 * AVERROR_OPTION_NOT_FOUND if no matching option exists
677 * AVERROR(ERANGE) if the value is out of range
678 * AVERROR(EINVAL) if the value is not valid
679 */
690 /**
691 * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
692 * caller still owns val is and responsible for freeing it.
693 */
695
696 /**
697 * Set a binary option to an integer list.
698 *
699 * @param obj AVClass object to set options on
700 * @param name name of the binary option
701 * @param val pointer to an integer list (must have the correct type with
702 * regard to the contents of the list)
703 * @param term list terminator (usually 0 or -1)
704 * @param flags search flags
705 */
706 #define av_opt_set_int_list(obj, name, val, term, flags) \
707 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
708 AVERROR(EINVAL) : \
709 av_opt_set_bin(obj, name, (const uint8_t *)(val), \
710 av_int_list_length(val, term) * sizeof(*(val)), flags))
711
712 /**
713 * @}
714 */
715
716 /**
717 * @defgroup opt_get_funcs Option getting functions
718 * @{
719 * Those functions get a value of the option with the given name from an object.
720 *
721 * @param[in] obj a struct whose first element is a pointer to an AVClass.
722 * @param[in] name name of the option to get.
723 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
724 * is passed here, then the option may be found in a child of obj.
725 * @param[out] out_val value of the option will be written here
726 * @return >=0 on success, a negative error code otherwise
727 */
728 /**
729 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
730 *
731 * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the option has
732 * AV_OPT_TYPE_STRING or AV_OPT_TYPE_BINARY and is set to NULL, *out_val will be set
733 * to NULL instead of an allocated empty string.
734 */
744 /**
745 * @param[out] out_val The returned dictionary is a copy of the actual value and must
746 * be freed with av_dict_free() by the caller
747 */
749 /**
750 * @}
751 */
752 /**
753 * Gets a pointer to the requested field in a struct.
754 * This function allows accessing a struct even when its fields are moved or
755 * renamed since the application making the access has been compiled,
756 *
757 * @returns a pointer to the field, it can be cast to the correct type and read
758 * or written to.
759 */
761
762 /**
763 * Free an AVOptionRanges struct and set it to NULL.
764 */
766
767 /**
768 * Get a list of allowed ranges for the given option.
769 *
770 * The returned list may depend on other fields in obj like for example profile.
771 *
772 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
773 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
774 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
775 *
776 * The result must be freed with av_opt_freep_ranges.
777 *
778 * @return number of compontents returned on success, a negative errro code otherwise
779 */
781
782 /**
783 * Copy options from src object into dest object.
784 *
785 * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
786 * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
787 *
788 * @param dest Object to copy from
789 * @param src Object to copy into
790 * @return 0 on success, negative on error
791 */
793
794 /**
795 * Get a default list of allowed ranges for the given option.
796 *
797 * This list is constructed without using the AVClass.query_ranges() callback
798 * and can be used as fallback from within the callback.
799 *
800 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
801 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
802 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
803 *
804 * The result must be freed with av_opt_free_ranges.
805 *
806 * @return number of compontents returned on success, a negative errro code otherwise
807 */
809
810 /**
811 * Check if given option is set to its default value.
812 *
813 * Options o must belong to the obj. This function must not be called to check child's options state.
814 * @see av_opt_is_set_to_default_by_name().
815 *
816 * @param obj AVClass object to check option on
817 * @param o option to be checked
818 * @return >0 when option is set to its default,
819 * 0 when option is not set its default,
820 * <0 on error
821 */
823
824 /**
825 * Check if given option is set to its default value.
826 *
827 * @param obj AVClass object to check option on
828 * @param name option name
829 * @param search_flags combination of AV_OPT_SEARCH_*
830 * @return >0 when option is set to its default,
831 * 0 when option is not set its default,
832 * <0 on error
833 */
835
836
837 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
838 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002
///< Serialize options that exactly match opt_flags only.
840 /**
841 * Serialize object's options.
842 *
843 * Create a string containing object's serialized options.
844 * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
845 * A key/value or pairs separator occurring in the serialized value or
846 * name string are escaped through the av_escape() function.
847 *
848 * @param[in] obj AVClass object to serialize
849 * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
850 * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
851 * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
852 * Buffer must be freed by the caller when is no longer needed.
853 * @param[in] key_val_sep character used to separate key from value
854 * @param[in] pairs_sep character used to separate two pairs from each other
855 * @return >= 0 on success, negative on error
856 * @warning Separators cannot be neither '\\' nor '0円'. They also cannot be the same.
857 */
859 const char key_val_sep, const char pairs_sep);
860 /**
861 * @}
862 */
863
864 #endif /* AVUTIL_OPT_H */
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
const char const char void * val
union AVOption::@264 default_val
the default value for scalar options
A single allowed range of values, or a single allowed value.
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
Accept to parse a value without a key; the key will then be returned as NULL.
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
void * av_opt_child_next(void *obj, void *prev)
Iterate over AVOptions-enabled children of obj.
const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
int av_set_options_string(void *ctx, const char *opts, const char *key_val_sep, const char *pairs_sep)
Parse the key/value pairs list in opts.
Convenience header that includes libavutil's core.
int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int size, int search_flags)
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer, const char key_val_sep, const char pairs_sep)
Serialize object's options.
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags)
Check if given option is set to its default value.
int av_opt_is_set_to_default(void *obj, const AVOption *o)
Check if given option is set to its default value.
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
int av_opt_set_from_string(void *ctx, const char *opts, const char *const *shorthand, const char *key_val_sep, const char *pairs_sep)
Parse the key-value pairs list in opts.
AVOptionRange ** range
Array of option ranges.
const char * help
short English help text
int av_opt_eval_int64(void *obj, const AVOption *o, const char *val, int64_t *int64_out)
int av_opt_set_double(void *obj, const char *name, double val, int search_flags)
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
void * av_opt_ptr(const AVClass *avclass, void *obj, const char *name)
Gets a pointer to the requested field in a struct.
static const uint16_t mask[17]
double max
maximum valid value for the option
int av_opt_eval_flags(void *obj, const AVOption *o, const char *val, int *flags_out)
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
const AVOption * av_opt_next(const void *obj, const AVOption *prev)
Iterate over all AVOptions belonging to obj.
Libavutil version macros.
const AVOption * av_opt_find(void *obj, const char *name, const char *unit, int opt_flags, int search_flags)
Look for an option in an object.
int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out)
int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt)
const char * unit
The logical unit to which the option belongs.
double component_min
Value's component range.
int av_opt_eval_q(void *obj, const AVOption *o, const char *val, AVRational *q_out)
int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags)
double min
minimum valid value for the option
void av_opt_set_defaults2(void *s, int mask, int flags)
Set the values of all AVOption fields to their default values.
int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags)
Set all the options from a given dictionary on an object.
offset must point to a pointer immediately followed by an int for the length
int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags)
Get a default list of allowed ranges for the given option.
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
int offset
The offset relative to the context structure where the option value is stored.
AVSampleFormat
Audio sample formats.
int av_opt_set_dict(void *obj, struct AVDictionary **options)
Set all the options from a given dictionary on an object.
int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
Show the obj options.
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
Describe the class of an AVClass context structure.
Rational number (pair of numerator and denominator).
offset must point to AVRational
int av_opt_eval_int(void *obj, const AVOption *o, const char *val, int *int_out)
offset must point to two consecutive integers
void av_opt_free(void *obj)
Free all allocated objects in obj.
const OptionDef options[]
int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags)
Get a list of allowed ranges for the given option.
double value_min
Value range.
Utilties for rational number calculation.
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
int av_opt_copy(void *dest, const void *src)
Copy options from src object into dest object.
int nb_ranges
Number of ranges per component.
List of AVOptionRange structs.
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
int av_opt_get_key_value(const char **ropts, const char *key_val_sep, const char *pairs_sep, unsigned flags, char **rkey, char **rval)
Extract a key-value pair from the beginning of a string.
int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name)
Check whether a particular flag is set in a flags field.
const AVOption * av_opt_find2(void *obj, const char *name, const char *unit, int opt_flags, int search_flags, void **target_obj)
Look for an option in an object.
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
AVPixelFormat
Pixel format.
int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
int nb_components
Number of componentes.
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)