FFmpeg 4.2.2
opt.h
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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#include "version.h"
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
233 AV_OPT_TYPE_IMAGE_SIZE, ///< offset must point to two consecutive integers
236 AV_OPT_TYPE_VIDEO_RATE, ///< offset must point to AVRational
241};
242
243/**
244 * AVOption
245 */
246typedef struct AVOption {
247 const char *name;
248
249 /**
250 * short English help text
251 * @todo What about other languages?
252 */
253 const char *help;
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 {
266 int64_t i64;
267 double dbl;
268 const char *str;
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
275 int flags;
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#define AV_OPT_FLAG_DEPRECATED (1<<17) ///< set if option is deprecated, users should refer to AVOption.help text for more information
293//FIXME think about enc-audio, ... style flags
294
295 /**
296 * The logical unit to which the option belongs. Non-constant
297 * options and corresponding named constants share the same
298 * unit. May be NULL.
299 */
300 const char *unit;
301} AVOption;
302
303/**
304 * A single allowed range of values, or a single allowed value.
305 */
306typedef struct AVOptionRange {
307 const char *str;
308 /**
309 * Value range.
310 * For string ranges this represents the min/max length.
311 * For dimensions this represents the min/max pixel count or width/height in multi-component case.
312 */
314 /**
315 * Value's component range.
316 * For string this represents the unicode range for chars, 0-127 limits to ASCII.
317 */
319 /**
320 * Range flag.
321 * If set to 1 the struct encodes a range, if set to 0 a single value.
322 */
325
326/**
327 * List of AVOptionRange structs.
328 */
329typedef struct AVOptionRanges {
330 /**
331 * Array of option ranges.
332 *
333 * Most of option types use just one component.
334 * Following describes multi-component option types:
335 *
336 * AV_OPT_TYPE_IMAGE_SIZE:
337 * component index 0: range of pixel count (width * height).
338 * component index 1: range of width.
339 * component index 2: range of height.
340 *
341 * @note To obtain multi-component version of this structure, user must
342 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
343 * av_opt_query_ranges_default function.
344 *
345 * Multi-component range can be read as in following example:
346 *
347 * @code
348 * int range_index, component_index;
349 * AVOptionRanges *ranges;
350 * AVOptionRange *range[3]; //may require more than 3 in the future.
351 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
352 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
353 * for (component_index = 0; component_index < ranges->nb_components; component_index++)
354 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
355 * //do something with range here.
356 * }
357 * av_opt_freep_ranges(&ranges);
358 * @endcode
359 */
361 /**
362 * Number of ranges per component.
363 */
365 /**
366 * Number of componentes.
367 */
370
371/**
372 * Show the obj options.
373 *
374 * @param req_flags requested flags for the options to show. Show only the
375 * options for which it is opt->flags & req_flags.
376 * @param rej_flags rejected flags for the options to show. Show only the
377 * options for which it is !(opt->flags & req_flags).
378 * @param av_log_obj log context to use for showing the options
379 */
380int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
381
382/**
383 * Set the values of all AVOption fields to their default values.
384 *
385 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
386 */
388
389/**
390 * Set the values of all AVOption fields to their default values. Only these
391 * AVOption fields for which (opt->flags & mask) == flags will have their
392 * default applied to s.
393 *
394 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
395 * @param mask combination of AV_OPT_FLAG_*
396 * @param flags combination of AV_OPT_FLAG_*
397 */
398void av_opt_set_defaults2(void *s, int mask, int flags);
399
400/**
401 * Parse the key/value pairs list in opts. For each key/value pair
402 * found, stores the value in the field in ctx that is named like the
403 * key. ctx must be an AVClass context, storing is done using
404 * AVOptions.
405 *
406 * @param opts options string to parse, may be NULL
407 * @param key_val_sep a 0-terminated list of characters used to
408 * separate key from value
409 * @param pairs_sep a 0-terminated list of characters used to separate
410 * two pairs from each other
411 * @return the number of successfully set key/value pairs, or a negative
412 * value corresponding to an AVERROR code in case of error:
413 * AVERROR(EINVAL) if opts cannot be parsed,
414 * the error code issued by av_opt_set() if a key/value pair
415 * cannot be set
416 */
417int av_set_options_string(void *ctx, const char *opts,
418 const char *key_val_sep, const char *pairs_sep);
419
420/**
421 * Parse the key-value pairs list in opts. For each key=value pair found,
422 * set the value of the corresponding option in ctx.
423 *
424 * @param ctx the AVClass object to set options on
425 * @param opts the options string, key-value pairs separated by a
426 * delimiter
427 * @param shorthand a NULL-terminated array of options names for shorthand
428 * notation: if the first field in opts has no key part,
429 * the key is taken from the first element of shorthand;
430 * then again for the second, etc., until either opts is
431 * finished, shorthand is finished or a named option is
432 * found; after that, all options must be named
433 * @param key_val_sep a 0-terminated list of characters used to separate
434 * key from value, for example '='
435 * @param pairs_sep a 0-terminated list of characters used to separate
436 * two pairs from each other, for example ':' or ','
437 * @return the number of successfully set key=value pairs, or a negative
438 * value corresponding to an AVERROR code in case of error:
439 * AVERROR(EINVAL) if opts cannot be parsed,
440 * the error code issued by av_set_string3() if a key/value pair
441 * cannot be set
442 *
443 * Options names must use only the following characters: a-z A-Z 0-9 - . / _
444 * Separators must use characters distinct from option names and from each
445 * other.
446 */
447int av_opt_set_from_string(void *ctx, const char *opts,
448 const char *const *shorthand,
449 const char *key_val_sep, const char *pairs_sep);
450/**
451 * Free all allocated objects in obj.
452 */
453void av_opt_free(void *obj);
454
455/**
456 * Check whether a particular flag is set in a flags field.
457 *
458 * @param field_name the name of the flag field option
459 * @param flag_name the name of the flag to check
460 * @return non-zero if the flag is set, zero if the flag isn't set,
461 * isn't of the right type, or the flags field doesn't exist.
462 */
463int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
464
465/**
466 * Set all the options from a given dictionary on an object.
467 *
468 * @param obj a struct whose first element is a pointer to AVClass
469 * @param options options to process. This dictionary will be freed and replaced
470 * by a new one containing all options not found in obj.
471 * Of course this new dictionary needs to be freed by caller
472 * with av_dict_free().
473 *
474 * @return 0 on success, a negative AVERROR if some option was found in obj,
475 * but could not be set.
476 *
477 * @see av_dict_copy()
478 */
479int av_opt_set_dict(void *obj, struct AVDictionary **options);
480
481
482/**
483 * Set all the options from a given dictionary on an object.
484 *
485 * @param obj a struct whose first element is a pointer to AVClass
486 * @param options options to process. This dictionary will be freed and replaced
487 * by a new one containing all options not found in obj.
488 * Of course this new dictionary needs to be freed by caller
489 * with av_dict_free().
490 * @param search_flags A combination of AV_OPT_SEARCH_*.
491 *
492 * @return 0 on success, a negative AVERROR if some option was found in obj,
493 * but could not be set.
494 *
495 * @see av_dict_copy()
496 */
497int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
498
499/**
500 * Extract a key-value pair from the beginning of a string.
501 *
502 * @param ropts pointer to the options string, will be updated to
503 * point to the rest of the string (one of the pairs_sep
504 * or the final NUL)
505 * @param key_val_sep a 0-terminated list of characters used to separate
506 * key from value, for example '='
507 * @param pairs_sep a 0-terminated list of characters used to separate
508 * two pairs from each other, for example ':' or ','
509 * @param flags flags; see the AV_OPT_FLAG_* values below
510 * @param rkey parsed key; must be freed using av_free()
511 * @param rval parsed value; must be freed using av_free()
512 *
513 * @return >=0 for success, or a negative value corresponding to an
514 * AVERROR code in case of error; in particular:
515 * AVERROR(EINVAL) if no key is present
516 *
517 */
518int av_opt_get_key_value(const char **ropts,
519 const char *key_val_sep, const char *pairs_sep,
520 unsigned flags,
521 char **rkey, char **rval);
522
523enum {
524
525 /**
526 * Accept to parse a value without a key; the key will then be returned
527 * as NULL.
528 */
530};
531
532/**
533 * @defgroup opt_eval_funcs Evaluating option strings
534 * @{
535 * This group of functions can be used to evaluate option strings
536 * and get numbers out of them. They do the same thing as av_opt_set(),
537 * except the result is written into the caller-supplied pointer.
538 *
539 * @param obj a struct whose first element is a pointer to AVClass.
540 * @param o an option for which the string is to be evaluated.
541 * @param val string to be evaluated.
542 * @param *_out value of the string will be written here.
543 *
544 * @return 0 on success, a negative number on failure.
545 */
546int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
547int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
548int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
549int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
550int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
551int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
552/**
553 * @}
554 */
555
556#define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
557 given object first. */
558/**
559 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
560 * instead of a required pointer to a struct containing AVClass. This is
561 * useful for searching for options without needing to allocate the corresponding
562 * object.
563 */
564#define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
565
566/**
567 * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
568 * rather than returning an empty string.
569 */
570#define AV_OPT_ALLOW_NULL (1 << 2)
571
572/**
573 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
574 * one component for certain option types.
575 * @see AVOptionRanges for details.
576 */
577#define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
578
579/**
580 * Look for an option in an object. Consider only options which
581 * have all the specified flags set.
582 *
583 * @param[in] obj A pointer to a struct whose first element is a
584 * pointer to an AVClass.
585 * Alternatively a double pointer to an AVClass, if
586 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
587 * @param[in] name The name of the option to look for.
588 * @param[in] unit When searching for named constants, name of the unit
589 * it belongs to.
590 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
591 * @param search_flags A combination of AV_OPT_SEARCH_*.
592 *
593 * @return A pointer to the option found, or NULL if no option
594 * was found.
595 *
596 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
597 * directly with av_opt_set(). Use special calls which take an options
598 * AVDictionary (e.g. avformat_open_input()) to set options found with this
599 * flag.
600 */
601const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
602 int opt_flags, int search_flags);
603
604/**
605 * Look for an option in an object. Consider only options which
606 * have all the specified flags set.
607 *
608 * @param[in] obj A pointer to a struct whose first element is a
609 * pointer to an AVClass.
610 * Alternatively a double pointer to an AVClass, if
611 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
612 * @param[in] name The name of the option to look for.
613 * @param[in] unit When searching for named constants, name of the unit
614 * it belongs to.
615 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
616 * @param search_flags A combination of AV_OPT_SEARCH_*.
617 * @param[out] target_obj if non-NULL, an object to which the option belongs will be
618 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
619 * in search_flags. This parameter is ignored if search_flags contain
620 * AV_OPT_SEARCH_FAKE_OBJ.
621 *
622 * @return A pointer to the option found, or NULL if no option
623 * was found.
624 */
625const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
626 int opt_flags, int search_flags, void **target_obj);
627
628/**
629 * Iterate over all AVOptions belonging to obj.
630 *
631 * @param obj an AVOptions-enabled struct or a double pointer to an
632 * AVClass describing it.
633 * @param prev result of the previous call to av_opt_next() on this object
634 * or NULL
635 * @return next AVOption or NULL
636 */
637const AVOption *av_opt_next(const void *obj, const AVOption *prev);
638
639/**
640 * Iterate over AVOptions-enabled children of obj.
641 *
642 * @param prev result of a previous call to this function or NULL
643 * @return next AVOptions-enabled child or NULL
644 */
645void *av_opt_child_next(void *obj, void *prev);
646
647/**
648 * Iterate over potential AVOptions-enabled children of parent.
649 *
650 * @param prev result of a previous call to this function or NULL
651 * @return AVClass corresponding to next potential child or NULL
652 */
653const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
654
655/**
656 * @defgroup opt_set_funcs Option setting functions
657 * @{
658 * Those functions set the field of obj with the given name to value.
659 *
660 * @param[in] obj A struct whose first element is a pointer to an AVClass.
661 * @param[in] name the name of the field to set
662 * @param[in] val The value to set. In case of av_opt_set() if the field is not
663 * of a string type, then the given string is parsed.
664 * SI postfixes and some named scalars are supported.
665 * If the field is of a numeric type, it has to be a numeric or named
666 * scalar. Behavior with more than one scalar and +- infix operators
667 * is undefined.
668 * If the field is of a flags type, it has to be a sequence of numeric
669 * scalars or named flags separated by '+' or '-'. Prefixing a flag
670 * with '+' causes it to be set without affecting the other flags;
671 * similarly, '-' unsets a flag.
672 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
673 * is passed here, then the option may be set on a child of obj.
674 *
675 * @return 0 if the value has been set, or an AVERROR code in case of
676 * error:
677 * AVERROR_OPTION_NOT_FOUND if no matching option exists
678 * AVERROR(ERANGE) if the value is out of range
679 * AVERROR(EINVAL) if the value is not valid
680 */
681int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
682int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
683int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
684int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
685int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
686int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
687int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
688int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
689int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
690int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
691/**
692 * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
693 * caller still owns val is and responsible for freeing it.
694 */
695int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
696
697/**
698 * Set a binary option to an integer list.
699 *
700 * @param obj AVClass object to set options on
701 * @param name name of the binary option
702 * @param val pointer to an integer list (must have the correct type with
703 * regard to the contents of the list)
704 * @param term list terminator (usually 0 or -1)
705 * @param flags search flags
706 */
707#define av_opt_set_int_list(obj, name, val, term, flags) \
708 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
709 AVERROR(EINVAL) : \
710 av_opt_set_bin(obj, name, (const uint8_t *)(val), \
711 av_int_list_length(val, term) * sizeof(*(val)), flags))
712
713/**
714 * @}
715 */
716
717/**
718 * @defgroup opt_get_funcs Option getting functions
719 * @{
720 * Those functions get a value of the option with the given name from an object.
721 *
722 * @param[in] obj a struct whose first element is a pointer to an AVClass.
723 * @param[in] name name of the option to get.
724 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
725 * is passed here, then the option may be found in a child of obj.
726 * @param[out] out_val value of the option will be written here
727 * @return >=0 on success, a negative error code otherwise
728 */
729/**
730 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
731 *
732 * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the option has
733 * AV_OPT_TYPE_STRING or AV_OPT_TYPE_BINARY and is set to NULL, *out_val will be set
734 * to NULL instead of an allocated empty string.
735 */
736int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
737int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
738int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
739int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
740int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
741int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
742int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
743int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
744int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
745/**
746 * @param[out] out_val The returned dictionary is a copy of the actual value and must
747 * be freed with av_dict_free() by the caller
748 */
749int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
750/**
751 * @}
752 */
753/**
754 * Gets a pointer to the requested field in a struct.
755 * This function allows accessing a struct even when its fields are moved or
756 * renamed since the application making the access has been compiled,
757 *
758 * @returns a pointer to the field, it can be cast to the correct type and read
759 * or written to.
760 */
761void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
762
763/**
764 * Free an AVOptionRanges struct and set it to NULL.
765 */
767
768/**
769 * Get a list of allowed ranges for the given option.
770 *
771 * The returned list may depend on other fields in obj like for example profile.
772 *
773 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
774 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
775 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
776 *
777 * The result must be freed with av_opt_freep_ranges.
778 *
779 * @return number of compontents returned on success, a negative errro code otherwise
780 */
781int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
782
783/**
784 * Copy options from src object into dest object.
785 *
786 * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
787 * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
788 *
789 * @param dest Object to copy from
790 * @param src Object to copy into
791 * @return 0 on success, negative on error
792 */
793int av_opt_copy(void *dest, const void *src);
794
795/**
796 * Get a default list of allowed ranges for the given option.
797 *
798 * This list is constructed without using the AVClass.query_ranges() callback
799 * and can be used as fallback from within the callback.
800 *
801 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
802 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
803 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
804 *
805 * The result must be freed with av_opt_free_ranges.
806 *
807 * @return number of compontents returned on success, a negative errro code otherwise
808 */
809int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
810
811/**
812 * Check if given option is set to its default value.
813 *
814 * Options o must belong to the obj. This function must not be called to check child's options state.
815 * @see av_opt_is_set_to_default_by_name().
816 *
817 * @param obj AVClass object to check option on
818 * @param o option to be checked
819 * @return >0 when option is set to its default,
820 * 0 when option is not set its default,
821 * <0 on error
822 */
823int av_opt_is_set_to_default(void *obj, const AVOption *o);
824
825/**
826 * Check if given option is set to its default value.
827 *
828 * @param obj AVClass object to check option on
829 * @param name option name
830 * @param search_flags combination of AV_OPT_SEARCH_*
831 * @return >0 when option is set to its default,
832 * 0 when option is not set its default,
833 * <0 on error
834 */
835int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
836
837
838#define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
839#define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
840
841/**
842 * Serialize object's options.
843 *
844 * Create a string containing object's serialized options.
845 * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
846 * A key/value or pairs separator occurring in the serialized value or
847 * name string are escaped through the av_escape() function.
848 *
849 * @param[in] obj AVClass object to serialize
850 * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
851 * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
852 * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
853 * Buffer must be freed by the caller when is no longer needed.
854 * @param[in] key_val_sep character used to separate key from value
855 * @param[in] pairs_sep character used to separate two pairs from each other
856 * @return >= 0 on success, negative on error
857 * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
858 */
859int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
860 const char key_val_sep, const char pairs_sep);
861/**
862 * @}
863 */
864
865#endif /* AVUTIL_OPT_H */
Convenience header that includes libavutil's core.
Public dictionary API.
int av_opt_copy(void *dest, const void *src)
Copy options from src object into dest object.
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.
int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags)
Set all the options from a given dictionary on an object.
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.
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_is_set_to_default(void *obj, const AVOption *o)
Check if given option is set to its default value.
void * av_opt_ptr(const AVClass *avclass, void *obj, const char *name)
Gets a pointer to the requested field in a struct.
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.
const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
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.
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags)
Get a list of allowed ranges for the given option.
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_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_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.
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.
AVOptionType
Definition: opt.h:221
void av_opt_free(void *obj)
Free all allocated objects in obj.
void * av_opt_child_next(void *obj, void *prev)
Iterate over AVOptions-enabled children of obj.
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
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_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.
const AVOption * av_opt_next(const void *obj, const AVOption *prev)
Iterate over all AVOptions belonging to obj.
@ AV_OPT_FLAG_IMPLICIT_KEY
Accept to parse a value without a key; the key will then be returned as NULL.
Definition: opt.h:529
@ AV_OPT_TYPE_IMAGE_SIZE
offset must point to two consecutive integers
Definition: opt.h:233
@ AV_OPT_TYPE_CONST
Definition: opt.h:232
@ AV_OPT_TYPE_PIXEL_FMT
Definition: opt.h:234
@ AV_OPT_TYPE_BINARY
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:229
@ AV_OPT_TYPE_DURATION
Definition: opt.h:237
@ AV_OPT_TYPE_CHANNEL_LAYOUT
Definition: opt.h:239
@ AV_OPT_TYPE_SAMPLE_FMT
Definition: opt.h:235
@ AV_OPT_TYPE_RATIONAL
Definition: opt.h:228
@ AV_OPT_TYPE_FLAGS
Definition: opt.h:222
@ AV_OPT_TYPE_VIDEO_RATE
offset must point to AVRational
Definition: opt.h:236
@ AV_OPT_TYPE_INT64
Definition: opt.h:224
@ AV_OPT_TYPE_UINT64
Definition: opt.h:231
@ AV_OPT_TYPE_INT
Definition: opt.h:223
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:225
@ AV_OPT_TYPE_FLOAT
Definition: opt.h:226
@ AV_OPT_TYPE_DICT
Definition: opt.h:230
@ AV_OPT_TYPE_BOOL
Definition: opt.h:240
@ AV_OPT_TYPE_STRING
Definition: opt.h:227
@ AV_OPT_TYPE_COLOR
Definition: opt.h:238
struct AVDictionary AVDictionary
Definition: dict.h:86
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
int av_opt_eval_int(void *obj, const AVOption *o, const char *val, int *int_out)
int av_opt_eval_q(void *obj, const AVOption *o, const char *val, AVRational *q_out)
int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out)
int av_opt_eval_int64(void *obj, const AVOption *o, const char *val, int64_t *int64_out)
int av_opt_eval_flags(void *obj, const AVOption *o, const char *val, int *flags_out)
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt)
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
int av_opt_set_double(void *obj, const char *name, double val, int search_flags)
int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int size, int search_flags)
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags)
swscale version macros
pixel format definitions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
Utilties for rational number calculation.
Describe the class of an AVClass context structure.
Definition: log.h:67
A single allowed range of values, or a single allowed value.
Definition: opt.h:306
double component_max
Definition: opt.h:318
double component_min
Value's component range.
Definition: opt.h:318
const char * str
Definition: opt.h:307
double value_max
Definition: opt.h:313
double value_min
Value range.
Definition: opt.h:313
int is_range
Range flag.
Definition: opt.h:323
List of AVOptionRange structs.
Definition: opt.h:329
int nb_ranges
Number of ranges per component.
Definition: opt.h:364
AVOptionRange ** range
Array of option ranges.
Definition: opt.h:360
int nb_components
Number of componentes.
Definition: opt.h:368
AVOption.
Definition: opt.h:246
double max
maximum valid value for the option
Definition: opt.h:273
int offset
The offset relative to the context structure where the option value is stored.
Definition: opt.h:259
const char * unit
The logical unit to which the option belongs.
Definition: opt.h:300
AVRational q
Definition: opt.h:270
const char * str
Definition: opt.h:268
const char * help
short English help text
Definition: opt.h:253
const char * name
Definition: opt.h:247
int64_t i64
Definition: opt.h:266
double min
minimum valid value for the option
Definition: opt.h:272
int flags
Definition: opt.h:275
union AVOption::@10 default_val
the default value for scalar options
enum AVOptionType type
Definition: opt.h:260
double dbl
Definition: opt.h:267
Rational number (pair of numerator and denominator).
Definition: rational.h:58