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 "channel_layout.h"
33#include "dict.h"
34#include "log.h"
35#include "pixfmt.h"
36#include "samplefmt.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 * There are two modes of access to members of AVOption and its child structs.
47 * One is called 'native access', and refers to access from the code that
48 * declares the AVOption in question. The other is 'foreign access', and refers
49 * to access from other code.
50 *
51 * Certain struct members in this header are documented as 'native access only'
52 * or similar - it means that only the code that declared the AVOption in
53 * question is allowed to access the field. This allows us to extend the
54 * semantics of those fields without breaking API compatibility.
55 *
56 * @section avoptions_implement Implementing AVOptions
57 * This section describes how to add AVOptions capabilities to a struct.
58 *
59 * All AVOptions-related information is stored in an AVClass. Therefore
60 * the first member of the struct should be a pointer to an AVClass describing it.
61 * The option field of the AVClass must be set to a NULL-terminated static array
62 * of AVOptions. Each AVOption must have a non-empty name, a type, a default
63 * value and for number-type AVOptions also a range of allowed values. It must
64 * also declare an offset in bytes from the start of the struct, where the field
65 * associated with this AVOption is located. Other fields in the AVOption struct
66 * should also be set when applicable, but are not required.
67 *
68 * The following example illustrates an AVOptions-enabled struct:
69 * @code
70 * typedef struct test_struct {
71 * const AVClass *class;
72 * int int_opt;
73 * char *str_opt;
74 * uint8_t *bin_opt;
75 * int bin_len;
76 * } test_struct;
77 *
78 * static const AVOption test_options[] = {
79 * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
80 * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
81 * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
82 * AV_OPT_TYPE_STRING },
83 * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
84 * AV_OPT_TYPE_BINARY },
85 * { NULL },
86 * };
87 *
88 * static const AVClass test_class = {
89 * .class_name = "test class",
90 * .item_name = av_default_item_name,
91 * .option = test_options,
92 * .version = LIBAVUTIL_VERSION_INT,
93 * };
94 * @endcode
95 *
96 * Next, when allocating your struct, you must ensure that the AVClass pointer
97 * is set to the correct value. Then, av_opt_set_defaults() can be called to
98 * initialize defaults. After that the struct is ready to be used with the
99 * AVOptions API.
100 *
101 * When cleaning up, you may use the av_opt_free() function to automatically
102 * free all the allocated string and binary options.
103 *
104 * Continuing with the above example:
105 *
106 * @code
107 * test_struct *alloc_test_struct(void)
108 * {
109 * test_struct *ret = av_mallocz(sizeof(*ret));
110 * ret->class = &test_class;
111 * av_opt_set_defaults(ret);
112 * return ret;
113 * }
114 * void free_test_struct(test_struct **foo)
115 * {
116 * av_opt_free(*foo);
117 * av_freep(foo);
118 * }
119 * @endcode
120 *
121 * @subsection avoptions_implement_nesting Nesting
122 * It may happen that an AVOptions-enabled struct contains another
123 * AVOptions-enabled struct as a member (e.g. AVCodecContext in
124 * libavcodec exports generic options, while its priv_data field exports
125 * codec-specific options). In such a case, it is possible to set up the
126 * parent struct to export a child's options. To do that, simply
127 * implement AVClass.child_next() and AVClass.child_class_iterate() in the
128 * parent struct's AVClass.
129 * Assuming that the test_struct from above now also contains a
130 * child_struct field:
131 *
132 * @code
133 * typedef struct child_struct {
134 * AVClass *class;
135 * int flags_opt;
136 * } child_struct;
137 * static const AVOption child_opts[] = {
138 * { "test_flags", "This is a test option of flags type.",
139 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
140 * { NULL },
141 * };
142 * static const AVClass child_class = {
143 * .class_name = "child class",
144 * .item_name = av_default_item_name,
145 * .option = child_opts,
146 * .version = LIBAVUTIL_VERSION_INT,
147 * };
148 *
149 * void *child_next(void *obj, void *prev)
150 * {
151 * test_struct *t = obj;
152 * if (!prev && t->child_struct)
153 * return t->child_struct;
154 * return NULL
155 * }
156 * const AVClass child_class_iterate(void **iter)
157 * {
158 * const AVClass *c = *iter ? NULL : &child_class;
159 * *iter = (void*)(uintptr_t)c;
160 * return c;
161 * }
162 * @endcode
163 * Putting child_next() and child_class_iterate() as defined above into
164 * test_class will now make child_struct's options accessible through
165 * test_struct (again, proper setup as described above needs to be done on
166 * child_struct right after it is created).
167 *
168 * From the above example it might not be clear why both child_next()
169 * and child_class_iterate() are needed. The distinction is that child_next()
170 * iterates over actually existing objects, while child_class_iterate()
171 * iterates over all possible child classes. E.g. if an AVCodecContext
172 * was initialized to use a codec which has private options, then its
173 * child_next() will return AVCodecContext.priv_data and finish
174 * iterating. OTOH child_class_iterate() on AVCodecContext.av_class will
175 * iterate over all available codecs with private options.
176 *
177 * @subsection avoptions_implement_named_constants Named constants
178 * It is possible to create named constants for options. Simply set the unit
179 * field of the option the constants should apply to a string and
180 * create the constants themselves as options of type AV_OPT_TYPE_CONST
181 * with their unit field set to the same string.
182 * Their default_val field should contain the value of the named
183 * constant.
184 * For example, to add some named constants for the test_flags option
185 * above, put the following into the child_opts array:
186 * @code
187 * { "test_flags", "This is a test option of flags type.",
188 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
189 * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
190 * @endcode
191 *
192 * @section avoptions_use Using AVOptions
193 * This section deals with accessing options in an AVOptions-enabled struct.
194 * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
195 * AVFormatContext in libavformat.
196 *
197 * @subsection avoptions_use_examine Examining AVOptions
198 * The basic functions for examining options are av_opt_next(), which iterates
199 * over all options defined for one object, and av_opt_find(), which searches
200 * for an option with the given name.
201 *
202 * The situation is more complicated with nesting. An AVOptions-enabled struct
203 * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
204 * to av_opt_find() will make the function search children recursively.
205 *
206 * For enumerating there are basically two cases. The first is when you want to
207 * get all options that may potentially exist on the struct and its children
208 * (e.g. when constructing documentation). In that case you should call
209 * av_opt_child_class_iterate() recursively on the parent struct's AVClass. The
210 * second case is when you have an already initialized struct with all its
211 * children and you want to get all options that can be actually written or read
212 * from it. In that case you should call av_opt_child_next() recursively (and
213 * av_opt_next() on each result).
214 *
215 * @subsection avoptions_use_get_set Reading and writing AVOptions
216 * When setting options, you often have a string read directly from the
217 * user. In such a case, simply passing it to av_opt_set() is enough. For
218 * non-string type options, av_opt_set() will parse the string according to the
219 * option type.
220 *
221 * Similarly av_opt_get() will read any option type and convert it to a string
222 * which will be returned. Do not forget that the string is allocated, so you
223 * have to free it with av_free().
224 *
225 * In some cases it may be more convenient to put all options into an
226 * AVDictionary and call av_opt_set_dict() on it. A specific case of this
227 * are the format/codec open functions in lavf/lavc which take a dictionary
228 * filled with option as a parameter. This makes it possible to set some options
229 * that cannot be set otherwise, since e.g. the input file format is not known
230 * before the file is actually opened.
231 */
232
233enum AVOptionType{
234 AV_OPT_TYPE_FLAGS = 1,
235 AV_OPT_TYPE_INT,
236 AV_OPT_TYPE_INT64,
237 AV_OPT_TYPE_DOUBLE,
238 AV_OPT_TYPE_FLOAT,
239 AV_OPT_TYPE_STRING,
240 AV_OPT_TYPE_RATIONAL,
241 AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
242 AV_OPT_TYPE_DICT,
243 AV_OPT_TYPE_UINT64,
244 AV_OPT_TYPE_CONST,
245 AV_OPT_TYPE_IMAGE_SIZE, ///< offset must point to two consecutive integers
246 AV_OPT_TYPE_PIXEL_FMT,
247 AV_OPT_TYPE_SAMPLE_FMT,
248 AV_OPT_TYPE_VIDEO_RATE, ///< offset must point to AVRational
249 AV_OPT_TYPE_DURATION,
250 AV_OPT_TYPE_COLOR,
251 AV_OPT_TYPE_BOOL,
252 AV_OPT_TYPE_CHLAYOUT,
253
254 /**
255 * May be combined with another regular option type to declare an array
256 * option.
257 *
258 * For array options, @ref AVOption.offset should refer to a pointer
259 * corresponding to the option type. The pointer should be immediately
260 * followed by an unsigned int that will store the number of elements in the
261 * array.
262 */
263 AV_OPT_TYPE_FLAG_ARRAY = (1 << 16),
264};
265
266/**
267 * A generic parameter which can be set by the user for muxing or encoding.
268 */
269#define AV_OPT_FLAG_ENCODING_PARAM (1 << 0)
270/**
271 * A generic parameter which can be set by the user for demuxing or decoding.
272 */
273#define AV_OPT_FLAG_DECODING_PARAM (1 << 1)
274#define AV_OPT_FLAG_AUDIO_PARAM (1 << 3)
275#define AV_OPT_FLAG_VIDEO_PARAM (1 << 4)
276#define AV_OPT_FLAG_SUBTITLE_PARAM (1 << 5)
277/**
278 * The option is intended for exporting values to the caller.
279 */
280#define AV_OPT_FLAG_EXPORT (1 << 6)
281/**
282 * The option may not be set through the AVOptions API, only read.
283 * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
284 */
285#define AV_OPT_FLAG_READONLY (1 << 7)
286/**
287 * A generic parameter which can be set by the user for bit stream filtering.
288 */
289#define AV_OPT_FLAG_BSF_PARAM (1 << 8)
290
291/**
292 * A generic parameter which can be set by the user at runtime.
293 */
294#define AV_OPT_FLAG_RUNTIME_PARAM (1 << 15)
295/**
296 * A generic parameter which can be set by the user for filtering.
297 */
298#define AV_OPT_FLAG_FILTERING_PARAM (1 << 16)
299/**
300 * Set if option is deprecated, users should refer to AVOption.help text for
301 * more information.
302 */
303#define AV_OPT_FLAG_DEPRECATED (1 << 17)
304/**
305 * Set if option constants can also reside in child objects.
306 */
307#define AV_OPT_FLAG_CHILD_CONSTS (1 << 18)
308
309/**
310 * May be set as default_val for AV_OPT_TYPE_FLAG_ARRAY options.
311 */
312typedef struct AVOptionArrayDef {
313 /**
314 * Native access only.
315 *
316 * Default value of the option, as would be serialized by av_opt_get() (i.e.
317 * using the value of sep as the separator).
318 */
319 const char *def;
320
321 /**
322 * Minimum number of elements in the array. When this field is non-zero, def
323 * must be non-NULL and contain at least this number of elements.
324 */
325 unsigned size_min;
326 /**
327 * Maximum number of elements in the array, 0 when unlimited.
328 */
329 unsigned size_max;
330
331 /**
332 * Separator between array elements in string representations of this
333 * option, used by av_opt_set() and av_opt_get(). It must be a printable
334 * ASCII character, excluding alphanumeric and the backslash. A comma is
335 * used when sep=0.
336 *
337 * The separator and the backslash must be backslash-escaped in order to
338 * appear in string representations of the option value.
339 */
340 char sep;
341} AVOptionArrayDef;
342
343/**
344 * AVOption
345 */
346typedef struct AVOption {
347 const char *name;
348
349 /**
350 * short English help text
351 * @todo What about other languages?
352 */
353 const char *help;
354
355 /**
356 * Native access only.
357 *
358 * The offset relative to the context structure where the option
359 * value is stored. It should be 0 for named constants.
360 */
361 int offset;
362 enum AVOptionType type;
363
364 /**
365 * Native access only, except when documented otherwise.
366 * the default value for scalar options
367 */
368 union {
369 int64_t i64;
370 double dbl;
371 const char *str;
372 /* TODO those are unused now */
373 AVRational q;
374
375 /**
376 * Used for AV_OPT_TYPE_FLAG_ARRAY options. May be NULL.
377 *
378 * Foreign access to some members allowed, as noted in AVOptionArrayDef
379 * documentation.
380 */
381 const AVOptionArrayDef *arr;
382 } default_val;
383 double min; ///< minimum valid value for the option
384 double max; ///< maximum valid value for the option
385
386 /**
387 * A combination of AV_OPT_FLAG_*.
388 */
389 int flags;
390
391 /**
392 * The logical unit to which the option belongs. Non-constant
393 * options and corresponding named constants share the same
394 * unit. May be NULL.
395 */
396 const char *unit;
397} AVOption;
398
399/**
400 * A single allowed range of values, or a single allowed value.
401 */
402typedef struct AVOptionRange {
403 const char *str;
404 /**
405 * Value range.
406 * For string ranges this represents the min/max length.
407 * For dimensions this represents the min/max pixel count or width/height in multi-component case.
408 */
409 double value_min, value_max;
410 /**
411 * Value's component range.
412 * For string this represents the unicode range for chars, 0-127 limits to ASCII.
413 */
414 double component_min, component_max;
415 /**
416 * Range flag.
417 * If set to 1 the struct encodes a range, if set to 0 a single value.
418 */
419 int is_range;
420} AVOptionRange;
421
422/**
423 * List of AVOptionRange structs.
424 */
425typedef struct AVOptionRanges {
426 /**
427 * Array of option ranges.
428 *
429 * Most of option types use just one component.
430 * Following describes multi-component option types:
431 *
432 * AV_OPT_TYPE_IMAGE_SIZE:
433 * component index 0: range of pixel count (width * height).
434 * component index 1: range of width.
435 * component index 2: range of height.
436 *
437 * @note To obtain multi-component version of this structure, user must
438 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
439 * av_opt_query_ranges_default function.
440 *
441 * Multi-component range can be read as in following example:
442 *
443 * @code
444 * int range_index, component_index;
445 * AVOptionRanges *ranges;
446 * AVOptionRange *range[3]; //may require more than 3 in the future.
447 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
448 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
449 * for (component_index = 0; component_index < ranges->nb_components; component_index++)
450 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
451 * //do something with range here.
452 * }
453 * av_opt_freep_ranges(&ranges);
454 * @endcode
455 */
456 AVOptionRange **range;
457 /**
458 * Number of ranges per component.
459 */
460 int nb_ranges;
461 /**
462 * Number of componentes.
463 */
464 int nb_components;
465} AVOptionRanges;
466
467/**
468 * @defgroup opt_mng AVOption (un)initialization and inspection.
469 * @{
470 */
471
472/**
473 * Set the values of all AVOption fields to their default values.
474 *
475 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
476 */
477void av_opt_set_defaults(void *s);
478
479/**
480 * Set the values of all AVOption fields to their default values. Only these
481 * AVOption fields for which (opt->flags & mask) == flags will have their
482 * default applied to s.
483 *
484 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
485 * @param mask combination of AV_OPT_FLAG_*
486 * @param flags combination of AV_OPT_FLAG_*
487 */
488void av_opt_set_defaults2(void *s, int mask, int flags);
489
490/**
491 * Free all allocated objects in obj.
492 */
493void av_opt_free(void *obj);
494
495/**
496 * Iterate over all AVOptions belonging to obj.
497 *
498 * @param obj an AVOptions-enabled struct or a double pointer to an
499 * AVClass describing it.
500 * @param prev result of the previous call to av_opt_next() on this object
501 * or NULL
502 * @return next AVOption or NULL
503 */
504const AVOption *av_opt_next(const void *obj, const AVOption *prev);
505
506/**
507 * Iterate over AVOptions-enabled children of obj.
508 *
509 * @param prev result of a previous call to this function or NULL
510 * @return next AVOptions-enabled child or NULL
511 */
512void *av_opt_child_next(void *obj, void *prev);
513
514/**
515 * Iterate over potential AVOptions-enabled children of parent.
516 *
517 * @param iter a pointer where iteration state is stored.
518 * @return AVClass corresponding to next potential child or NULL
519 */
520const AVClass *av_opt_child_class_iterate(const AVClass *parent, void **iter);
521
522#define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
523 given object first. */
524/**
525 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
526 * instead of a required pointer to a struct containing AVClass. This is
527 * useful for searching for options without needing to allocate the corresponding
528 * object.
529 */
530#define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
531
532/**
533 * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
534 * rather than returning an empty string.
535 */
536#define AV_OPT_ALLOW_NULL (1 << 2)
537
538/**
539 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
540 * one component for certain option types.
541 * @see AVOptionRanges for details.
542 */
543#define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
544
545/**
546 * Look for an option in an object. Consider only options which
547 * have all the specified flags set.
548 *
549 * @param[in] obj A pointer to a struct whose first element is a
550 * pointer to an AVClass.
551 * Alternatively a double pointer to an AVClass, if
552 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
553 * @param[in] name The name of the option to look for.
554 * @param[in] unit When searching for named constants, name of the unit
555 * it belongs to.
556 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
557 * @param search_flags A combination of AV_OPT_SEARCH_*.
558 *
559 * @return A pointer to the option found, or NULL if no option
560 * was found.
561 *
562 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
563 * directly with av_opt_set(). Use special calls which take an options
564 * AVDictionary (e.g. avformat_open_input()) to set options found with this
565 * flag.
566 */
567const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
568 int opt_flags, int search_flags);
569
570/**
571 * Look for an option in an object. Consider only options which
572 * have all the specified flags set.
573 *
574 * @param[in] obj A pointer to a struct whose first element is a
575 * pointer to an AVClass.
576 * Alternatively a double pointer to an AVClass, if
577 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
578 * @param[in] name The name of the option to look for.
579 * @param[in] unit When searching for named constants, name of the unit
580 * it belongs to.
581 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
582 * @param search_flags A combination of AV_OPT_SEARCH_*.
583 * @param[out] target_obj if non-NULL, an object to which the option belongs will be
584 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
585 * in search_flags. This parameter is ignored if search_flags contain
586 * AV_OPT_SEARCH_FAKE_OBJ.
587 *
588 * @return A pointer to the option found, or NULL if no option
589 * was found.
590 */
591const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
592 int opt_flags, int search_flags, void **target_obj);
593
594/**
595 * Show the obj options.
596 *
597 * @param req_flags requested flags for the options to show. Show only the
598 * options for which it is opt->flags & req_flags.
599 * @param rej_flags rejected flags for the options to show. Show only the
600 * options for which it is !(opt->flags & req_flags).
601 * @param av_log_obj log context to use for showing the options
602 */
603int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
604
605/**
606 * Extract a key-value pair from the beginning of a string.
607 *
608 * @param ropts pointer to the options string, will be updated to
609 * point to the rest of the string (one of the pairs_sep
610 * or the final NUL)
611 * @param key_val_sep a 0-terminated list of characters used to separate
612 * key from value, for example '='
613 * @param pairs_sep a 0-terminated list of characters used to separate
614 * two pairs from each other, for example ':' or ','
615 * @param flags flags; see the AV_OPT_FLAG_* values below
616 * @param rkey parsed key; must be freed using av_free()
617 * @param rval parsed value; must be freed using av_free()
618 *
619 * @return >=0 for success, or a negative value corresponding to an
620 * AVERROR code in case of error; in particular:
621 * AVERROR(EINVAL) if no key is present
622 *
623 */
624int av_opt_get_key_value(const char **ropts,
625 const char *key_val_sep, const char *pairs_sep,
626 unsigned flags,
627 char **rkey, char **rval);
628
629enum {
630
631 /**
632 * Accept to parse a value without a key; the key will then be returned
633 * as NULL.
634 */
635 AV_OPT_FLAG_IMPLICIT_KEY = 1,
636};
637
638/**
639 * @}
640 */
641
642/**
643 * @defgroup opt_write Setting and modifying option values
644 * @{
645 */
646
647/**
648 * Parse the key/value pairs list in opts. For each key/value pair
649 * found, stores the value in the field in ctx that is named like the
650 * key. ctx must be an AVClass context, storing is done using
651 * AVOptions.
652 *
653 * @param opts options string to parse, may be NULL
654 * @param key_val_sep a 0-terminated list of characters used to
655 * separate key from value
656 * @param pairs_sep a 0-terminated list of characters used to separate
657 * two pairs from each other
658 * @return the number of successfully set key/value pairs, or a negative
659 * value corresponding to an AVERROR code in case of error:
660 * AVERROR(EINVAL) if opts cannot be parsed,
661 * the error code issued by av_opt_set() if a key/value pair
662 * cannot be set
663 */
664int av_set_options_string(void *ctx, const char *opts,
665 const char *key_val_sep, const char *pairs_sep);
666
667/**
668 * Parse the key-value pairs list in opts. For each key=value pair found,
669 * set the value of the corresponding option in ctx.
670 *
671 * @param ctx the AVClass object to set options on
672 * @param opts the options string, key-value pairs separated by a
673 * delimiter
674 * @param shorthand a NULL-terminated array of options names for shorthand
675 * notation: if the first field in opts has no key part,
676 * the key is taken from the first element of shorthand;
677 * then again for the second, etc., until either opts is
678 * finished, shorthand is finished or a named option is
679 * found; after that, all options must be named
680 * @param key_val_sep a 0-terminated list of characters used to separate
681 * key from value, for example '='
682 * @param pairs_sep a 0-terminated list of characters used to separate
683 * two pairs from each other, for example ':' or ','
684 * @return the number of successfully set key=value pairs, or a negative
685 * value corresponding to an AVERROR code in case of error:
686 * AVERROR(EINVAL) if opts cannot be parsed,
687 * the error code issued by av_set_string3() if a key/value pair
688 * cannot be set
689 *
690 * Options names must use only the following characters: a-z A-Z 0-9 - . / _
691 * Separators must use characters distinct from option names and from each
692 * other.
693 */
694int av_opt_set_from_string(void *ctx, const char *opts,
695 const char *const *shorthand,
696 const char *key_val_sep, const char *pairs_sep);
697
698/**
699 * Set all the options from a given dictionary on an object.
700 *
701 * @param obj a struct whose first element is a pointer to AVClass
702 * @param options options to process. This dictionary will be freed and replaced
703 * by a new one containing all options not found in obj.
704 * Of course this new dictionary needs to be freed by caller
705 * with av_dict_free().
706 *
707 * @return 0 on success, a negative AVERROR if some option was found in obj,
708 * but could not be set.
709 *
710 * @see av_dict_copy()
711 */
712int av_opt_set_dict(void *obj, struct AVDictionary **options);
713
714
715/**
716 * Set all the options from a given dictionary on an object.
717 *
718 * @param obj a struct whose first element is a pointer to AVClass
719 * @param options options to process. This dictionary will be freed and replaced
720 * by a new one containing all options not found in obj.
721 * Of course this new dictionary needs to be freed by caller
722 * with av_dict_free().
723 * @param search_flags A combination of AV_OPT_SEARCH_*.
724 *
725 * @return 0 on success, a negative AVERROR if some option was found in obj,
726 * but could not be set.
727 *
728 * @see av_dict_copy()
729 */
730int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
731
732/**
733 * Copy options from src object into dest object.
734 *
735 * The underlying AVClass of both src and dest must coincide. The guarantee
736 * below does not apply if this is not fulfilled.
737 *
738 * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
739 * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
740 *
741 * Even on error it is guaranteed that allocated options from src and dest
742 * no longer alias each other afterwards; in particular calling av_opt_free()
743 * on both src and dest is safe afterwards if dest has been memdup'ed from src.
744 *
745 * @param dest Object to copy from
746 * @param src Object to copy into
747 * @return 0 on success, negative on error
748 */
749int av_opt_copy(void *dest, const void *src);
750
751/**
752 * @defgroup opt_set_funcs Option setting functions
753 * @{
754 * Those functions set the field of obj with the given name to value.
755 *
756 * @param[in] obj A struct whose first element is a pointer to an AVClass.
757 * @param[in] name the name of the field to set
758 * @param[in] val The value to set. In case of av_opt_set() if the field is not
759 * of a string type, then the given string is parsed.
760 * SI postfixes and some named scalars are supported.
761 * If the field is of a numeric type, it has to be a numeric or named
762 * scalar. Behavior with more than one scalar and +- infix operators
763 * is undefined.
764 * If the field is of a flags type, it has to be a sequence of numeric
765 * scalars or named flags separated by '+' or '-'. Prefixing a flag
766 * with '+' causes it to be set without affecting the other flags;
767 * similarly, '-' unsets a flag.
768 * If the field is of a dictionary type, it has to be a ':' separated list of
769 * key=value parameters. Values containing ':' special characters must be
770 * escaped.
771 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
772 * is passed here, then the option may be set on a child of obj.
773 *
774 * @return 0 if the value has been set, or an AVERROR code in case of
775 * error:
776 * AVERROR_OPTION_NOT_FOUND if no matching option exists
777 * AVERROR(ERANGE) if the value is out of range
778 * AVERROR(EINVAL) if the value is not valid
779 */
780int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
781int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
782int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
783int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
784int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
785int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
786int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
787int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
788int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
789int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *layout, int search_flags);
790/**
791 * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
792 * caller still owns val is and responsible for freeing it.
793 */
794int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
795
796/**
797 * Set a binary option to an integer list.
798 *
799 * @param obj AVClass object to set options on
800 * @param name name of the binary option
801 * @param val pointer to an integer list (must have the correct type with
802 * regard to the contents of the list)
803 * @param term list terminator (usually 0 or -1)
804 * @param flags search flags
805 */
806#define av_opt_set_int_list(obj, name, val, term, flags) \
807 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
808 AVERROR(EINVAL) : \
809 av_opt_set_bin(obj, name, (const uint8_t *)(val), \
810 av_int_list_length(val, term) * sizeof(*(val)), flags))
811
812/**
813 * @}
814 * @}
815 */
816
817/**
818 * @defgroup opt_read Reading option values
819 * @{
820 */
821
822/**
823 * @defgroup opt_get_funcs Option getting functions
824 * @{
825 * Those functions get a value of the option with the given name from an object.
826 *
827 * @param[in] obj a struct whose first element is a pointer to an AVClass.
828 * @param[in] name name of the option to get.
829 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
830 * is passed here, then the option may be found in a child of obj.
831 * @param[out] out_val value of the option will be written here
832 * @return >=0 on success, a negative error code otherwise
833 */
834/**
835 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
836 *
837 * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the
838 * option is of type AV_OPT_TYPE_STRING, AV_OPT_TYPE_BINARY or AV_OPT_TYPE_DICT
839 * and is set to NULL, *out_val will be set to NULL instead of an allocated
840 * empty string.
841 */
842int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
843int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
844int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
845int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
846int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
847int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
848int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
849int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
850int av_opt_get_chlayout(void *obj, const char *name, int search_flags, AVChannelLayout *layout);
851/**
852 * @param[out] out_val The returned dictionary is a copy of the actual value and must
853 * be freed with av_dict_free() by the caller
854 */
855int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
856/**
857 * @}
858 */
859
860/**
861 * @defgroup opt_eval_funcs Evaluating option strings
862 * @{
863 * This group of functions can be used to evaluate option strings
864 * and get numbers out of them. They do the same thing as av_opt_set(),
865 * except the result is written into the caller-supplied pointer.
866 *
867 * @param obj a struct whose first element is a pointer to AVClass.
868 * @param o an option for which the string is to be evaluated.
869 * @param val string to be evaluated.
870 * @param *_out value of the string will be written here.
871 *
872 * @return 0 on success, a negative number on failure.
873 */
874int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
875int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
876int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
877int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
878int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
879int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
880/**
881 * @}
882 */
883
884/**
885 * Gets a pointer to the requested field in a struct.
886 * This function allows accessing a struct even when its fields are moved or
887 * renamed since the application making the access has been compiled,
888 *
889 * @returns a pointer to the field, it can be cast to the correct type and read
890 * or written to.
891 */
892void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
893
894/**
895 * Check if given option is set to its default value.
896 *
897 * Options o must belong to the obj. This function must not be called to check child's options state.
898 * @see av_opt_is_set_to_default_by_name().
899 *
900 * @param obj AVClass object to check option on
901 * @param o option to be checked
902 * @return >0 when option is set to its default,
903 * 0 when option is not set its default,
904 * <0 on error
905 */
906int av_opt_is_set_to_default(void *obj, const AVOption *o);
907
908/**
909 * Check if given option is set to its default value.
910 *
911 * @param obj AVClass object to check option on
912 * @param name option name
913 * @param search_flags combination of AV_OPT_SEARCH_*
914 * @return >0 when option is set to its default,
915 * 0 when option is not set its default,
916 * <0 on error
917 */
918int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
919
920/**
921 * Check whether a particular flag is set in a flags field.
922 *
923 * @param field_name the name of the flag field option
924 * @param flag_name the name of the flag to check
925 * @return non-zero if the flag is set, zero if the flag isn't set,
926 * isn't of the right type, or the flags field doesn't exist.
927 */
928int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
929
930#define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
931#define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
932
933/**
934 * Serialize object's options.
935 *
936 * Create a string containing object's serialized options.
937 * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
938 * A key/value or pairs separator occurring in the serialized value or
939 * name string are escaped through the av_escape() function.
940 *
941 * @param[in] obj AVClass object to serialize
942 * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
943 * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
944 * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
945 * Buffer must be freed by the caller when is no longer needed.
946 * @param[in] key_val_sep character used to separate key from value
947 * @param[in] pairs_sep character used to separate two pairs from each other
948 * @return >= 0 on success, negative on error
949 * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
950 */
951int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
952 const char key_val_sep, const char pairs_sep);
953
954/**
955 * @}
956 */
957
958/**
959 * Free an AVOptionRanges struct and set it to NULL.
960 */
961void av_opt_freep_ranges(AVOptionRanges **ranges);
962
963/**
964 * Get a list of allowed ranges for the given option.
965 *
966 * The returned list may depend on other fields in obj like for example profile.
967 *
968 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
969 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
970 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
971 *
972 * The result must be freed with av_opt_freep_ranges.
973 *
974 * @return number of compontents returned on success, a negative errro code otherwise
975 */
976int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
977
978/**
979 * Get a default list of allowed ranges for the given option.
980 *
981 * This list is constructed without using the AVClass.query_ranges() callback
982 * and can be used as fallback from within the callback.
983 *
984 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
985 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
986 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
987 *
988 * The result must be freed with av_opt_free_ranges.
989 *
990 * @return number of compontents returned on success, a negative errro code otherwise
991 */
992int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
993
994/**
995 * @}
996 */
997
998#endif /* AVUTIL_OPT_H */
999