FFmpeg 7.1.1
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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 "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_scope Scope of AVOptions
57 *
58 * AVOptions is designed to support any set of multimedia configuration options
59 * that can be defined at compile-time. Although it is mainly used to expose
60 * FFmpeg options, you are welcome to adapt it to your own use case.
61 *
62 * No single approach can ever fully solve the problem of configuration,
63 * but please submit a patch if you believe you have found a problem
64 * that is best solved by extending AVOptions.
65 *
66 * @section avoptions_implement Implementing AVOptions
67 * This section describes how to add AVOptions capabilities to a struct.
68 *
69 * All AVOptions-related information is stored in an AVClass. Therefore
70 * the first member of the struct should be a pointer to an AVClass describing it.
71 * The option field of the AVClass must be set to a NULL-terminated static array
72 * of AVOptions. Each AVOption must have a non-empty name, a type, a default
73 * value and for number-type AVOptions also a range of allowed values. It must
74 * also declare an offset in bytes from the start of the struct, where the field
75 * associated with this AVOption is located. Other fields in the AVOption struct
76 * should also be set when applicable, but are not required.
77 *
78 * The following example illustrates an AVOptions-enabled struct:
79 * @code
80 * typedef struct test_struct {
81 * const AVClass *class;
82 * int int_opt;
83 * char *str_opt;
84 * uint8_t *bin_opt;
85 * int bin_len;
86 * } test_struct;
87 *
88 * static const AVOption test_options[] = {
89 * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
90 * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
91 * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
92 * AV_OPT_TYPE_STRING },
93 * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
94 * AV_OPT_TYPE_BINARY },
95 * { NULL },
96 * };
97 *
98 * static const AVClass test_class = {
99 * .class_name = "test class",
100 * .item_name = av_default_item_name,
101 * .option = test_options,
102 * .version = LIBAVUTIL_VERSION_INT,
103 * };
104 * @endcode
105 *
106 * Next, when allocating your struct, you must ensure that the AVClass pointer
107 * is set to the correct value. Then, av_opt_set_defaults() can be called to
108 * initialize defaults. After that the struct is ready to be used with the
109 * AVOptions API.
110 *
111 * When cleaning up, you may use the av_opt_free() function to automatically
112 * free all the allocated string and binary options.
113 *
114 * Continuing with the above example:
115 *
116 * @code
117 * test_struct *alloc_test_struct(void)
118 * {
119 * test_struct *ret = av_mallocz(sizeof(*ret));
120 * ret->class = &test_class;
121 * av_opt_set_defaults(ret);
122 * return ret;
123 * }
124 * void free_test_struct(test_struct **foo)
125 * {
126 * av_opt_free(*foo);
127 * av_freep(foo);
128 * }
129 * @endcode
130 *
131 * @subsection avoptions_implement_nesting Nesting
132 * It may happen that an AVOptions-enabled struct contains another
133 * AVOptions-enabled struct as a member (e.g. AVCodecContext in
134 * libavcodec exports generic options, while its priv_data field exports
135 * codec-specific options). In such a case, it is possible to set up the
136 * parent struct to export a child's options. To do that, simply
137 * implement AVClass.child_next() and AVClass.child_class_iterate() in the
138 * parent struct's AVClass.
139 * Assuming that the test_struct from above now also contains a
140 * child_struct field:
141 *
142 * @code
143 * typedef struct child_struct {
144 * AVClass *class;
145 * int flags_opt;
146 * } child_struct;
147 * static const AVOption child_opts[] = {
148 * { "test_flags", "This is a test option of flags type.",
149 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
150 * { NULL },
151 * };
152 * static const AVClass child_class = {
153 * .class_name = "child class",
154 * .item_name = av_default_item_name,
155 * .option = child_opts,
156 * .version = LIBAVUTIL_VERSION_INT,
157 * };
158 *
159 * void *child_next(void *obj, void *prev)
160 * {
161 * test_struct *t = obj;
162 * if (!prev && t->child_struct)
163 * return t->child_struct;
164 * return NULL
165 * }
166 * const AVClass child_class_iterate(void **iter)
167 * {
168 * const AVClass *c = *iter ? NULL : &child_class;
169 * *iter = (void*)(uintptr_t)c;
170 * return c;
171 * }
172 * @endcode
173 * Putting child_next() and child_class_iterate() as defined above into
174 * test_class will now make child_struct's options accessible through
175 * test_struct (again, proper setup as described above needs to be done on
176 * child_struct right after it is created).
177 *
178 * From the above example it might not be clear why both child_next()
179 * and child_class_iterate() are needed. The distinction is that child_next()
180 * iterates over actually existing objects, while child_class_iterate()
181 * iterates over all possible child classes. E.g. if an AVCodecContext
182 * was initialized to use a codec which has private options, then its
183 * child_next() will return AVCodecContext.priv_data and finish
184 * iterating. OTOH child_class_iterate() on AVCodecContext.av_class will
185 * iterate over all available codecs with private options.
186 *
187 * @subsection avoptions_implement_named_constants Named constants
188 * It is possible to create named constants for options. Simply set the unit
189 * field of the option the constants should apply to a string and
190 * create the constants themselves as options of type AV_OPT_TYPE_CONST
191 * with their unit field set to the same string.
192 * Their default_val field should contain the value of the named
193 * constant.
194 * For example, to add some named constants for the test_flags option
195 * above, put the following into the child_opts array:
196 * @code
197 * { "test_flags", "This is a test option of flags type.",
198 * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
199 * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
200 * @endcode
201 *
202 * @section avoptions_use Using AVOptions
203 * This section deals with accessing options in an AVOptions-enabled struct.
204 * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
205 * AVFormatContext in libavformat.
206 *
207 * @subsection avoptions_use_examine Examining AVOptions
208 * The basic functions for examining options are av_opt_next(), which iterates
209 * over all options defined for one object, and av_opt_find(), which searches
210 * for an option with the given name.
211 *
212 * The situation is more complicated with nesting. An AVOptions-enabled struct
213 * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
214 * to av_opt_find() will make the function search children recursively.
215 *
216 * For enumerating there are basically two cases. The first is when you want to
217 * get all options that may potentially exist on the struct and its children
218 * (e.g. when constructing documentation). In that case you should call
219 * av_opt_child_class_iterate() recursively on the parent struct's AVClass. The
220 * second case is when you have an already initialized struct with all its
221 * children and you want to get all options that can be actually written or read
222 * from it. In that case you should call av_opt_child_next() recursively (and
223 * av_opt_next() on each result).
224 *
225 * @subsection avoptions_use_get_set Reading and writing AVOptions
226 * When setting options, you often have a string read directly from the
227 * user. In such a case, simply passing it to av_opt_set() is enough. For
228 * non-string type options, av_opt_set() will parse the string according to the
229 * option type.
230 *
231 * Similarly av_opt_get() will read any option type and convert it to a string
232 * which will be returned. Do not forget that the string is allocated, so you
233 * have to free it with av_free().
234 *
235 * In some cases it may be more convenient to put all options into an
236 * AVDictionary and call av_opt_set_dict() on it. A specific case of this
237 * are the format/codec open functions in lavf/lavc which take a dictionary
238 * filled with option as a parameter. This makes it possible to set some options
239 * that cannot be set otherwise, since e.g. the input file format is not known
240 * before the file is actually opened.
241 */
242
243/**
244 * An option type determines:
245 * - for native access, the underlying C type of the field that an AVOption
246 * refers to;
247 * - for foreign access, the semantics of accessing the option through this API,
248 * e.g. which av_opt_get_*() and av_opt_set_*() functions can be called, or
249 * what format will av_opt_get()/av_opt_set() expect/produce.
250 */
252 /**
253 * Underlying C type is unsigned int.
254 */
256 /**
257 * Underlying C type is int.
258 */
260 /**
261 * Underlying C type is int64_t.
262 */
264 /**
265 * Underlying C type is double.
266 */
268 /**
269 * Underlying C type is float.
270 */
272 /**
273 * Underlying C type is a uint8_t* that is either NULL or points to a C
274 * string allocated with the av_malloc() family of functions.
275 */
277 /**
278 * Underlying C type is AVRational.
279 */
281 /**
282 * Underlying C type is a uint8_t* that is either NULL or points to an array
283 * allocated with the av_malloc() family of functions. The pointer is
284 * immediately followed by an int containing the array length in bytes.
285 */
287 /**
288 * Underlying C type is AVDictionary*.
289 */
291 /**
292 * Underlying C type is uint64_t.
293 */
295 /**
296 * Special option type for declaring named constants. Does not correspond to
297 * an actual field in the object, offset must be 0.
298 */
300 /**
301 * Underlying C type is two consecutive integers.
302 */
304 /**
305 * Underlying C type is enum AVPixelFormat.
306 */
308 /**
309 * Underlying C type is enum AVSampleFormat.
310 */
312 /**
313 * Underlying C type is AVRational.
314 */
316 /**
317 * Underlying C type is int64_t.
318 */
320 /**
321 * Underlying C type is uint8_t[4].
322 */
324 /**
325 * Underlying C type is int.
326 */
328 /**
329 * Underlying C type is AVChannelLayout.
330 */
332 /**
333 * Underlying C type is unsigned int.
334 */
336
337 /**
338 * May be combined with another regular option type to declare an array
339 * option.
340 *
341 * For array options, @ref AVOption.offset should refer to a pointer
342 * corresponding to the option type. The pointer should be immediately
343 * followed by an unsigned int that will store the number of elements in the
344 * array.
345 */
347};
348
349/**
350 * A generic parameter which can be set by the user for muxing or encoding.
351 */
352#define AV_OPT_FLAG_ENCODING_PARAM (1 << 0)
353/**
354 * A generic parameter which can be set by the user for demuxing or decoding.
355 */
356#define AV_OPT_FLAG_DECODING_PARAM (1 << 1)
357#define AV_OPT_FLAG_AUDIO_PARAM (1 << 3)
358#define AV_OPT_FLAG_VIDEO_PARAM (1 << 4)
359#define AV_OPT_FLAG_SUBTITLE_PARAM (1 << 5)
360/**
361 * The option is intended for exporting values to the caller.
362 */
363#define AV_OPT_FLAG_EXPORT (1 << 6)
364/**
365 * The option may not be set through the AVOptions API, only read.
366 * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
367 */
368#define AV_OPT_FLAG_READONLY (1 << 7)
369/**
370 * A generic parameter which can be set by the user for bit stream filtering.
371 */
372#define AV_OPT_FLAG_BSF_PARAM (1 << 8)
373
374/**
375 * A generic parameter which can be set by the user at runtime.
376 */
377#define AV_OPT_FLAG_RUNTIME_PARAM (1 << 15)
378/**
379 * A generic parameter which can be set by the user for filtering.
380 */
381#define AV_OPT_FLAG_FILTERING_PARAM (1 << 16)
382/**
383 * Set if option is deprecated, users should refer to AVOption.help text for
384 * more information.
385 */
386#define AV_OPT_FLAG_DEPRECATED (1 << 17)
387/**
388 * Set if option constants can also reside in child objects.
389 */
390#define AV_OPT_FLAG_CHILD_CONSTS (1 << 18)
391
392/**
393 * May be set as default_val for AV_OPT_TYPE_FLAG_ARRAY options.
394 */
395typedef struct AVOptionArrayDef {
396 /**
397 * Native access only.
398 *
399 * Default value of the option, as would be serialized by av_opt_get() (i.e.
400 * using the value of sep as the separator).
401 */
402 const char *def;
403
404 /**
405 * Minimum number of elements in the array. When this field is non-zero, def
406 * must be non-NULL and contain at least this number of elements.
407 */
408 unsigned size_min;
409 /**
410 * Maximum number of elements in the array, 0 when unlimited.
411 */
412 unsigned size_max;
413
414 /**
415 * Separator between array elements in string representations of this
416 * option, used by av_opt_set() and av_opt_get(). It must be a printable
417 * ASCII character, excluding alphanumeric and the backslash. A comma is
418 * used when sep=0.
419 *
420 * The separator and the backslash must be backslash-escaped in order to
421 * appear in string representations of the option value.
422 */
423 char sep;
425
426/**
427 * AVOption
428 */
429typedef struct AVOption {
430 const char *name;
431
432 /**
433 * short English help text
434 * @todo What about other languages?
435 */
436 const char *help;
437
438 /**
439 * Native access only.
440 *
441 * The offset relative to the context structure where the option
442 * value is stored. It should be 0 for named constants.
443 */
446
447 /**
448 * Native access only, except when documented otherwise.
449 * the default value for scalar options
450 */
451 union {
452 int64_t i64;
453 double dbl;
454 const char *str;
455 /* TODO those are unused now */
457
458 /**
459 * Used for AV_OPT_TYPE_FLAG_ARRAY options. May be NULL.
460 *
461 * Foreign access to some members allowed, as noted in AVOptionArrayDef
462 * documentation.
463 */
466 double min; ///< minimum valid value for the option
467 double max; ///< maximum valid value for the option
468
469 /**
470 * A combination of AV_OPT_FLAG_*.
471 */
472 int flags;
473
474 /**
475 * The logical unit to which the option belongs. Non-constant
476 * options and corresponding named constants share the same
477 * unit. May be NULL.
478 */
479 const char *unit;
480} AVOption;
481
482/**
483 * A single allowed range of values, or a single allowed value.
484 */
485typedef struct AVOptionRange {
486 const char *str;
487 /**
488 * Value range.
489 * For string ranges this represents the min/max length.
490 * For dimensions this represents the min/max pixel count or width/height in multi-component case.
491 */
493 /**
494 * Value's component range.
495 * For string this represents the unicode range for chars, 0-127 limits to ASCII.
496 */
498 /**
499 * Range flag.
500 * If set to 1 the struct encodes a range, if set to 0 a single value.
501 */
504
505/**
506 * List of AVOptionRange structs.
507 */
508typedef struct AVOptionRanges {
509 /**
510 * Array of option ranges.
511 *
512 * Most of option types use just one component.
513 * Following describes multi-component option types:
514 *
515 * AV_OPT_TYPE_IMAGE_SIZE:
516 * component index 0: range of pixel count (width * height).
517 * component index 1: range of width.
518 * component index 2: range of height.
519 *
520 * @note To obtain multi-component version of this structure, user must
521 * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
522 * av_opt_query_ranges_default function.
523 *
524 * Multi-component range can be read as in following example:
525 *
526 * @code
527 * int range_index, component_index;
528 * AVOptionRanges *ranges;
529 * AVOptionRange *range[3]; //may require more than 3 in the future.
530 * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
531 * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
532 * for (component_index = 0; component_index < ranges->nb_components; component_index++)
533 * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
534 * //do something with range here.
535 * }
536 * av_opt_freep_ranges(&ranges);
537 * @endcode
538 */
540 /**
541 * Number of ranges per component.
542 */
544 /**
545 * Number of componentes.
546 */
549
550/**
551 * @defgroup opt_mng AVOption (un)initialization and inspection.
552 * @{
553 */
554
555/**
556 * Set the values of all AVOption fields to their default values.
557 *
558 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
559 */
561
562/**
563 * Set the values of all AVOption fields to their default values. Only these
564 * AVOption fields for which (opt->flags & mask) == flags will have their
565 * default applied to s.
566 *
567 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
568 * @param mask combination of AV_OPT_FLAG_*
569 * @param flags combination of AV_OPT_FLAG_*
570 */
571void av_opt_set_defaults2(void *s, int mask, int flags);
572
573/**
574 * Free all allocated objects in obj.
575 */
576void av_opt_free(void *obj);
577
578/**
579 * Iterate over all AVOptions belonging to obj.
580 *
581 * @param obj an AVOptions-enabled struct or a double pointer to an
582 * AVClass describing it.
583 * @param prev result of the previous call to av_opt_next() on this object
584 * or NULL
585 * @return next AVOption or NULL
586 */
587const AVOption *av_opt_next(const void *obj, const AVOption *prev);
588
589/**
590 * Iterate over AVOptions-enabled children of obj.
591 *
592 * @param prev result of a previous call to this function or NULL
593 * @return next AVOptions-enabled child or NULL
594 */
595void *av_opt_child_next(void *obj, void *prev);
596
597/**
598 * Iterate over potential AVOptions-enabled children of parent.
599 *
600 * @param iter a pointer where iteration state is stored.
601 * @return AVClass corresponding to next potential child or NULL
602 */
603const AVClass *av_opt_child_class_iterate(const AVClass *parent, void **iter);
604
605#define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
606 given object first. */
607/**
608 * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
609 * instead of a required pointer to a struct containing AVClass. This is
610 * useful for searching for options without needing to allocate the corresponding
611 * object.
612 */
613#define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
614
615/**
616 * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
617 * rather than returning an empty string.
618 */
619#define AV_OPT_ALLOW_NULL (1 << 2)
620
621/**
622 * May be used with av_opt_set_array() to signal that new elements should
623 * replace the existing ones in the indicated range.
624 */
625#define AV_OPT_ARRAY_REPLACE (1 << 3)
626
627/**
628 * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
629 * one component for certain option types.
630 * @see AVOptionRanges for details.
631 */
632#define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
633
634/**
635 * Look for an option in an object. Consider only options which
636 * have all the specified flags set.
637 *
638 * @param[in] obj A pointer to a struct whose first element is a
639 * pointer to an AVClass.
640 * Alternatively a double pointer to an AVClass, if
641 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
642 * @param[in] name The name of the option to look for.
643 * @param[in] unit When searching for named constants, name of the unit
644 * it belongs to.
645 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
646 * @param search_flags A combination of AV_OPT_SEARCH_*.
647 *
648 * @return A pointer to the option found, or NULL if no option
649 * was found.
650 *
651 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
652 * directly with av_opt_set(). Use special calls which take an options
653 * AVDictionary (e.g. avformat_open_input()) to set options found with this
654 * flag.
655 */
656const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
657 int opt_flags, int search_flags);
658
659/**
660 * Look for an option in an object. Consider only options which
661 * have all the specified flags set.
662 *
663 * @param[in] obj A pointer to a struct whose first element is a
664 * pointer to an AVClass.
665 * Alternatively a double pointer to an AVClass, if
666 * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
667 * @param[in] name The name of the option to look for.
668 * @param[in] unit When searching for named constants, name of the unit
669 * it belongs to.
670 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
671 * @param search_flags A combination of AV_OPT_SEARCH_*.
672 * @param[out] target_obj if non-NULL, an object to which the option belongs will be
673 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
674 * in search_flags. This parameter is ignored if search_flags contain
675 * AV_OPT_SEARCH_FAKE_OBJ.
676 *
677 * @return A pointer to the option found, or NULL if no option
678 * was found.
679 */
680const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
681 int opt_flags, int search_flags, void **target_obj);
682
683/**
684 * Show the obj options.
685 *
686 * @param req_flags requested flags for the options to show. Show only the
687 * options for which it is opt->flags & req_flags.
688 * @param rej_flags rejected flags for the options to show. Show only the
689 * options for which it is !(opt->flags & req_flags).
690 * @param av_log_obj log context to use for showing the options
691 */
692int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
693
694/**
695 * Extract a key-value pair from the beginning of a string.
696 *
697 * @param ropts pointer to the options string, will be updated to
698 * point to the rest of the string (one of the pairs_sep
699 * or the final NUL)
700 * @param key_val_sep a 0-terminated list of characters used to separate
701 * key from value, for example '='
702 * @param pairs_sep a 0-terminated list of characters used to separate
703 * two pairs from each other, for example ':' or ','
704 * @param flags flags; see the AV_OPT_FLAG_* values below
705 * @param rkey parsed key; must be freed using av_free()
706 * @param rval parsed value; must be freed using av_free()
707 *
708 * @return >=0 for success, or a negative value corresponding to an
709 * AVERROR code in case of error; in particular:
710 * AVERROR(EINVAL) if no key is present
711 *
712 */
713int av_opt_get_key_value(const char **ropts,
714 const char *key_val_sep, const char *pairs_sep,
715 unsigned flags,
716 char **rkey, char **rval);
717
718enum {
719
720 /**
721 * Accept to parse a value without a key; the key will then be returned
722 * as NULL.
723 */
725};
726
727/**
728 * @}
729 */
730
731/**
732 * @defgroup opt_write Setting and modifying option values
733 * @{
734 */
735
736/**
737 * Parse the key/value pairs list in opts. For each key/value pair
738 * found, stores the value in the field in ctx that is named like the
739 * key. ctx must be an AVClass context, storing is done using
740 * AVOptions.
741 *
742 * @param opts options string to parse, may be NULL
743 * @param key_val_sep a 0-terminated list of characters used to
744 * separate key from value
745 * @param pairs_sep a 0-terminated list of characters used to separate
746 * two pairs from each other
747 * @return the number of successfully set key/value pairs, or a negative
748 * value corresponding to an AVERROR code in case of error:
749 * AVERROR(EINVAL) if opts cannot be parsed,
750 * the error code issued by av_opt_set() if a key/value pair
751 * cannot be set
752 */
753int av_set_options_string(void *ctx, const char *opts,
754 const char *key_val_sep, const char *pairs_sep);
755
756/**
757 * Parse the key-value pairs list in opts. For each key=value pair found,
758 * set the value of the corresponding option in ctx.
759 *
760 * @param ctx the AVClass object to set options on
761 * @param opts the options string, key-value pairs separated by a
762 * delimiter
763 * @param shorthand a NULL-terminated array of options names for shorthand
764 * notation: if the first field in opts has no key part,
765 * the key is taken from the first element of shorthand;
766 * then again for the second, etc., until either opts is
767 * finished, shorthand is finished or a named option is
768 * found; after that, all options must be named
769 * @param key_val_sep a 0-terminated list of characters used to separate
770 * key from value, for example '='
771 * @param pairs_sep a 0-terminated list of characters used to separate
772 * two pairs from each other, for example ':' or ','
773 * @return the number of successfully set key=value pairs, or a negative
774 * value corresponding to an AVERROR code in case of error:
775 * AVERROR(EINVAL) if opts cannot be parsed,
776 * the error code issued by av_set_string3() if a key/value pair
777 * cannot be set
778 *
779 * Options names must use only the following characters: a-z A-Z 0-9 - . / _
780 * Separators must use characters distinct from option names and from each
781 * other.
782 */
783int av_opt_set_from_string(void *ctx, const char *opts,
784 const char *const *shorthand,
785 const char *key_val_sep, const char *pairs_sep);
786
787/**
788 * Set all the options from a given dictionary on an object.
789 *
790 * @param obj a struct whose first element is a pointer to AVClass
791 * @param options options to process. This dictionary will be freed and replaced
792 * by a new one containing all options not found in obj.
793 * Of course this new dictionary needs to be freed by caller
794 * with av_dict_free().
795 *
796 * @return 0 on success, a negative AVERROR if some option was found in obj,
797 * but could not be set.
798 *
799 * @see av_dict_copy()
800 */
801int av_opt_set_dict(void *obj, struct AVDictionary **options);
802
803
804/**
805 * Set all the options from a given dictionary on an object.
806 *
807 * @param obj a struct whose first element is a pointer to AVClass
808 * @param options options to process. This dictionary will be freed and replaced
809 * by a new one containing all options not found in obj.
810 * Of course this new dictionary needs to be freed by caller
811 * with av_dict_free().
812 * @param search_flags A combination of AV_OPT_SEARCH_*.
813 *
814 * @return 0 on success, a negative AVERROR if some option was found in obj,
815 * but could not be set.
816 *
817 * @see av_dict_copy()
818 */
819int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
820
821/**
822 * Copy options from src object into dest object.
823 *
824 * The underlying AVClass of both src and dest must coincide. The guarantee
825 * below does not apply if this is not fulfilled.
826 *
827 * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
828 * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
829 *
830 * Even on error it is guaranteed that allocated options from src and dest
831 * no longer alias each other afterwards; in particular calling av_opt_free()
832 * on both src and dest is safe afterwards if dest has been memdup'ed from src.
833 *
834 * @param dest Object to copy from
835 * @param src Object to copy into
836 * @return 0 on success, negative on error
837 */
838int av_opt_copy(void *dest, const void *src);
839
840/**
841 * @defgroup opt_set_funcs Option setting functions
842 * @{
843 * Those functions set the field of obj with the given name to value.
844 *
845 * @param[in] obj A struct whose first element is a pointer to an AVClass.
846 * @param[in] name the name of the field to set
847 * @param[in] val The value to set. In case of av_opt_set() if the field is not
848 * of a string type, then the given string is parsed.
849 * SI postfixes and some named scalars are supported.
850 * If the field is of a numeric type, it has to be a numeric or named
851 * scalar. Behavior with more than one scalar and +- infix operators
852 * is undefined.
853 * If the field is of a flags type, it has to be a sequence of numeric
854 * scalars or named flags separated by '+' or '-'. Prefixing a flag
855 * with '+' causes it to be set without affecting the other flags;
856 * similarly, '-' unsets a flag.
857 * If the field is of a dictionary type, it has to be a ':' separated list of
858 * key=value parameters. Values containing ':' special characters must be
859 * escaped.
860 * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
861 * is passed here, then the option may be set on a child of obj.
862 *
863 * @return 0 if the value has been set, or an AVERROR code in case of
864 * error:
865 * AVERROR_OPTION_NOT_FOUND if no matching option exists
866 * AVERROR(ERANGE) if the value is out of range
867 * AVERROR(EINVAL) if the value is not valid
868 */
869int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
870int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
871int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
872int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
873int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
874int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
875int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
876int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
877int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
878/**
879 * @note Any old chlayout present is discarded and replaced with a copy of the new one. The
880 * caller still owns layout and is responsible for uninitializing it.
881 */
882int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *layout, int search_flags);
883/**
884 * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
885 * caller still owns val is and responsible for freeing it.
886 */
887int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
888
889/**
890 * Set a binary option to an integer list.
891 *
892 * @param obj AVClass object to set options on
893 * @param name name of the binary option
894 * @param val pointer to an integer list (must have the correct type with
895 * regard to the contents of the list)
896 * @param term list terminator (usually 0 or -1)
897 * @param flags search flags
898 */
899#define av_opt_set_int_list(obj, name, val, term, flags) \
900 (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
901 AVERROR(EINVAL) : \
902 av_opt_set_bin(obj, name, (const uint8_t *)(val), \
903 av_int_list_length(val, term) * sizeof(*(val)), flags))
904
905/**
906 * Add, replace, or remove elements for an array option. Which of these
907 * operations is performed depends on the values of val and search_flags.
908 *
909 * @param start_elem Index of the first array element to modify; must not be
910 * larger than array size as returned by
911 * av_opt_get_array_size().
912 * @param nb_elems number of array elements to modify; when val is NULL,
913 * start_elem+nb_elems must not be larger than array size as
914 * returned by av_opt_get_array_size()
915 *
916 * @param val_type Option type corresponding to the type of val, ignored when val is
917 * NULL.
918 *
919 * The effect of this function will will be as if av_opt_setX()
920 * was called for each element, where X is specified by type.
921 * E.g. AV_OPT_TYPE_STRING corresponds to av_opt_set().
922 *
923 * Typically this should be the same as the scalarized type of
924 * the AVOption being set, but certain conversions are also
925 * possible - the same as those done by the corresponding
926 * av_opt_set*() function. E.g. any option type can be set from
927 * a string, numeric types can be set from int64, double, or
928 * rational, etc.
929 *
930 * @param val Array with nb_elems elements or NULL.
931 *
932 * When NULL, nb_elems array elements starting at start_elem are
933 * removed from the array. Any array elements remaining at the end
934 * are shifted by nb_elems towards the first element in order to keep
935 * the array contiguous.
936 *
937 * Otherwise (val is non-NULL), the type of val must match the
938 * underlying C type as documented for val_type.
939 *
940 * When AV_OPT_ARRAY_REPLACE is not set in search_flags, the array is
941 * enlarged by nb_elems, and the contents of val are inserted at
942 * start_elem. Previously existing array elements from start_elem
943 * onwards (if present) are shifted by nb_elems away from the first
944 * element in order to make space for the new elements.
945 *
946 * When AV_OPT_ARRAY_REPLACE is set in search_flags, the contents
947 * of val replace existing array elements from start_elem to
948 * start_elem+nb_elems (if present). New array size is
949 * max(start_elem + nb_elems, old array size).
950 */
951int av_opt_set_array(void *obj, const char *name, int search_flags,
952 unsigned int start_elem, unsigned int nb_elems,
953 enum AVOptionType val_type, const void *val);
954
955/**
956 * @}
957 * @}
958 */
959
960/**
961 * @defgroup opt_read Reading option values
962 * @{
963 */
964
965/**
966 * @defgroup opt_get_funcs Option getting functions
967 * @{
968 * Those functions get a value of the option with the given name from an object.
969 *
970 * @param[in] obj a struct whose first element is a pointer to an AVClass.
971 * @param[in] name name of the option to get.
972 * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
973 * is passed here, then the option may be found in a child of obj.
974 * @param[out] out_val value of the option will be written here
975 * @return >=0 on success, a negative error code otherwise
976 */
977/**
978 * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
979 *
980 * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the
981 * option is of type AV_OPT_TYPE_STRING, AV_OPT_TYPE_BINARY or AV_OPT_TYPE_DICT
982 * and is set to NULL, *out_val will be set to NULL instead of an allocated
983 * empty string.
984 */
985int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
986int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
987int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
988int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
989int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
990int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
991int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
992int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
993/**
994 * @param[out] layout The returned layout is a copy of the actual value and must
995 * be freed with av_channel_layout_uninit() by the caller
996 */
997int av_opt_get_chlayout(void *obj, const char *name, int search_flags, AVChannelLayout *layout);
998/**
999 * @param[out] out_val The returned dictionary is a copy of the actual value and must
1000 * be freed with av_dict_free() by the caller
1001 */
1002int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
1003
1004/**
1005 * For an array-type option, get the number of elements in the array.
1006 */
1007int av_opt_get_array_size(void *obj, const char *name, int search_flags,
1008 unsigned int *out_val);
1009
1010/**
1011 * For an array-type option, retrieve the values of one or more array elements.
1012 *
1013 * @param start_elem index of the first array element to retrieve
1014 * @param nb_elems number of array elements to retrieve; start_elem+nb_elems
1015 * must not be larger than array size as returned by
1016 * av_opt_get_array_size()
1017 *
1018 * @param out_type Option type corresponding to the desired output.
1019 *
1020 * The array elements produced by this function will
1021 * will be as if av_opt_getX() was called for each element,
1022 * where X is specified by out_type. E.g. AV_OPT_TYPE_STRING
1023 * corresponds to av_opt_get().
1024 *
1025 * Typically this should be the same as the scalarized type of
1026 * the AVOption being retrieved, but certain conversions are
1027 * also possible - the same as those done by the corresponding
1028 * av_opt_get*() function. E.g. any option type can be retrieved
1029 * as a string, numeric types can be retrieved as int64, double,
1030 * or rational, etc.
1031 *
1032 * @param out_val Array with nb_elems members into which the output will be
1033 * written. The array type must match the underlying C type as
1034 * documented for out_type, and be zeroed on entry to this
1035 * function.
1036 *
1037 * For dynamically allocated types (strings, binary, dicts,
1038 * etc.), the result is owned and freed by the caller.
1039 */
1040int av_opt_get_array(void *obj, const char *name, int search_flags,
1041 unsigned int start_elem, unsigned int nb_elems,
1042 enum AVOptionType out_type, void *out_val);
1043/**
1044 * @}
1045 */
1046
1047/**
1048 * @defgroup opt_eval_funcs Evaluating option strings
1049 * @{
1050 * This group of functions can be used to evaluate option strings
1051 * and get numbers out of them. They do the same thing as av_opt_set(),
1052 * except the result is written into the caller-supplied pointer.
1053 *
1054 * @param obj a struct whose first element is a pointer to AVClass.
1055 * @param o an option for which the string is to be evaluated.
1056 * @param val string to be evaluated.
1057 * @param *_out value of the string will be written here.
1058 *
1059 * @return 0 on success, a negative number on failure.
1060 */
1061int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
1062int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
1063int av_opt_eval_uint (void *obj, const AVOption *o, const char *val, unsigned *uint_out);
1064int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
1065int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
1066int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
1067int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
1068/**
1069 * @}
1070 */
1071
1072/**
1073 * Gets a pointer to the requested field in a struct.
1074 * This function allows accessing a struct even when its fields are moved or
1075 * renamed since the application making the access has been compiled,
1076 *
1077 * @returns a pointer to the field, it can be cast to the correct type and read
1078 * or written to.
1079 */
1080void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
1081
1082/**
1083 * Check if given option is set to its default value.
1084 *
1085 * Options o must belong to the obj. This function must not be called to check child's options state.
1086 * @see av_opt_is_set_to_default_by_name().
1087 *
1088 * @param obj AVClass object to check option on
1089 * @param o option to be checked
1090 * @return >0 when option is set to its default,
1091 * 0 when option is not set its default,
1092 * <0 on error
1093 */
1094int av_opt_is_set_to_default(void *obj, const AVOption *o);
1095
1096/**
1097 * Check if given option is set to its default value.
1098 *
1099 * @param obj AVClass object to check option on
1100 * @param name option name
1101 * @param search_flags combination of AV_OPT_SEARCH_*
1102 * @return >0 when option is set to its default,
1103 * 0 when option is not set its default,
1104 * <0 on error
1105 */
1106int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
1107
1108/**
1109 * Check whether a particular flag is set in a flags field.
1110 *
1111 * @param field_name the name of the flag field option
1112 * @param flag_name the name of the flag to check
1113 * @return non-zero if the flag is set, zero if the flag isn't set,
1114 * isn't of the right type, or the flags field doesn't exist.
1115 */
1116int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
1117
1118#define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
1119#define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
1120#define AV_OPT_SERIALIZE_SEARCH_CHILDREN 0x00000004 ///< Serialize options in possible children of the given object.
1121
1122/**
1123 * Serialize object's options.
1124 *
1125 * Create a string containing object's serialized options.
1126 * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
1127 * A key/value or pairs separator occurring in the serialized value or
1128 * name string are escaped through the av_escape() function.
1129 *
1130 * @param[in] obj AVClass object to serialize
1131 * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
1132 * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
1133 * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
1134 * Buffer must be freed by the caller when is no longer needed.
1135 * @param[in] key_val_sep character used to separate key from value
1136 * @param[in] pairs_sep character used to separate two pairs from each other
1137 * @return >= 0 on success, negative on error
1138 * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
1139 */
1140int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
1141 const char key_val_sep, const char pairs_sep);
1142
1143/**
1144 * @}
1145 */
1146
1147/**
1148 * Free an AVOptionRanges struct and set it to NULL.
1149 */
1151
1152/**
1153 * Get a list of allowed ranges for the given option.
1154 *
1155 * The returned list may depend on other fields in obj like for example profile.
1156 *
1157 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
1158 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
1159 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
1160 *
1161 * The result must be freed with av_opt_freep_ranges.
1162 *
1163 * @return number of compontents returned on success, a negative errro code otherwise
1164 */
1165int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
1166
1167/**
1168 * Get a default list of allowed ranges for the given option.
1169 *
1170 * This list is constructed without using the AVClass.query_ranges() callback
1171 * and can be used as fallback from within the callback.
1172 *
1173 * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
1174 * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
1175 * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
1176 *
1177 * The result must be freed with av_opt_free_ranges.
1178 *
1179 * @return number of compontents returned on success, a negative errro code otherwise
1180 */
1181int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
1182
1183/**
1184 * @}
1185 */
1186
1187#endif /* AVUTIL_OPT_H */
Convenience header that includes libavutil's core.
Public libavutil channel layout APIs header.
Public dictionary API.
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.
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.
AVOptionType
An option type determines:
Definition opt.h:251
@ AV_OPT_TYPE_IMAGE_SIZE
Underlying C type is two consecutive integers.
Definition opt.h:303
@ AV_OPT_TYPE_CONST
Special option type for declaring named constants.
Definition opt.h:299
@ AV_OPT_TYPE_PIXEL_FMT
Underlying C type is enum AVPixelFormat.
Definition opt.h:307
@ AV_OPT_TYPE_BINARY
Underlying C type is a uint8_t* that is either NULL or points to an array allocated with the av_mallo...
Definition opt.h:286
@ AV_OPT_TYPE_DURATION
Underlying C type is int64_t.
Definition opt.h:319
@ AV_OPT_TYPE_FLAG_ARRAY
May be combined with another regular option type to declare an array option.
Definition opt.h:346
@ AV_OPT_TYPE_SAMPLE_FMT
Underlying C type is enum AVSampleFormat.
Definition opt.h:311
@ AV_OPT_TYPE_RATIONAL
Underlying C type is AVRational.
Definition opt.h:280
@ AV_OPT_TYPE_FLAGS
Underlying C type is unsigned int.
Definition opt.h:255
@ AV_OPT_TYPE_VIDEO_RATE
Underlying C type is AVRational.
Definition opt.h:315
@ AV_OPT_TYPE_INT64
Underlying C type is int64_t.
Definition opt.h:263
@ AV_OPT_TYPE_UINT64
Underlying C type is uint64_t.
Definition opt.h:294
@ AV_OPT_TYPE_INT
Underlying C type is int.
Definition opt.h:259
@ AV_OPT_TYPE_CHLAYOUT
Underlying C type is AVChannelLayout.
Definition opt.h:331
@ AV_OPT_TYPE_DOUBLE
Underlying C type is double.
Definition opt.h:267
@ AV_OPT_TYPE_FLOAT
Underlying C type is float.
Definition opt.h:271
@ AV_OPT_TYPE_DICT
Underlying C type is AVDictionary*.
Definition opt.h:290
@ AV_OPT_TYPE_BOOL
Underlying C type is int.
Definition opt.h:327
@ AV_OPT_TYPE_STRING
Underlying C type is a uint8_t* that is either NULL or points to a C string allocated with the av_mal...
Definition opt.h:276
@ AV_OPT_TYPE_COLOR
Underlying C type is uint8_t[4].
Definition opt.h:323
@ AV_OPT_TYPE_UINT
Underlying C type is unsigned int.
Definition opt.h:335
struct AVDictionary AVDictionary
Definition dict.h:94
AVSampleFormat
Audio sample formats.
Definition samplefmt.h:55
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
int av_opt_eval_uint(void *obj, const AVOption *o, const char *val, unsigned *uint_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_array(void *obj, const char *name, int search_flags, unsigned int start_elem, unsigned int nb_elems, enum AVOptionType out_type, void *out_val)
For an array-type option, retrieve the values of one or more array elements.
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
int av_opt_get_array_size(void *obj, const char *name, int search_flags, unsigned int *out_val)
For an array-type option, get the number of elements in the array.
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
int av_opt_get_chlayout(void *obj, const char *name, int search_flags, AVChannelLayout *layout)
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)
const AVClass * av_opt_child_class_iterate(const AVClass *parent, void **iter)
Iterate over potential AVOptions-enabled children of parent.
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.
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.
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_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:724
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_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_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_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_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_array(void *obj, const char *name, int search_flags, unsigned int start_elem, unsigned int nb_elems, enum AVOptionType val_type, const void *val)
Add, replace, or remove elements for an array option.
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_chlayout(void *obj, const char *name, const AVChannelLayout *layout, 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_copy(void *dest, const void *src)
Copy options from src object into dest object.
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_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.
int av_opt_set_dict(void *obj, struct AVDictionary **options)
Set all the options from a given dictionary on an object.
pixel format definitions
AVPixelFormat
Pixel format.
Definition pixfmt.h:71
Utilties for rational number calculation.
An AVChannelLayout holds information about the channel layout of audio data.
Describe the class of an AVClass context structure.
Definition log.h:66
May be set as default_val for AV_OPT_TYPE_FLAG_ARRAY options.
Definition opt.h:395
const char * def
Native access only.
Definition opt.h:402
unsigned size_min
Minimum number of elements in the array.
Definition opt.h:408
unsigned size_max
Maximum number of elements in the array, 0 when unlimited.
Definition opt.h:412
char sep
Separator between array elements in string representations of this option, used by av_opt_set() and a...
Definition opt.h:423
A single allowed range of values, or a single allowed value.
Definition opt.h:485
double component_max
Definition opt.h:497
double component_min
Value's component range.
Definition opt.h:497
const char * str
Definition opt.h:486
double value_max
Definition opt.h:492
double value_min
Value range.
Definition opt.h:492
int is_range
Range flag.
Definition opt.h:502
List of AVOptionRange structs.
Definition opt.h:508
int nb_ranges
Number of ranges per component.
Definition opt.h:543
AVOptionRange ** range
Array of option ranges.
Definition opt.h:539
int nb_components
Number of componentes.
Definition opt.h:547
AVOption.
Definition opt.h:429
double max
maximum valid value for the option
Definition opt.h:467
int offset
Native access only.
Definition opt.h:444
const char * unit
The logical unit to which the option belongs.
Definition opt.h:479
AVRational q
Definition opt.h:456
const char * str
Definition opt.h:454
union AVOption::@14 default_val
Native access only, except when documented otherwise.
const char * help
short English help text
Definition opt.h:436
const char * name
Definition opt.h:430
int64_t i64
Definition opt.h:452
const AVOptionArrayDef * arr
Used for AV_OPT_TYPE_FLAG_ARRAY options.
Definition opt.h:464
double min
minimum valid value for the option
Definition opt.h:466
int flags
A combination of AV_OPT_FLAG_*.
Definition opt.h:472
enum AVOptionType type
Definition opt.h:445
double dbl
Definition opt.h:453
Rational number (pair of numerator and denominator).
Definition rational.h:58