FFmpeg
opt.h
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1 /*
2  * AVOptions
3  * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVUTIL_OPT_H
23 #define AVUTIL_OPT_H
24 
25 /**
26  * @file
27  * AVOptions
28  */
29 
30 #include "rational.h"
31 #include "avutil.h"
32 #include "dict.h"
33 #include "log.h"
34 #include "pixfmt.h"
35 #include "samplefmt.h"
36 #include "version.h"
37 
38 /**
39  * @defgroup avoptions AVOptions
40  * @ingroup lavu_data
41  * @{
42  * AVOptions provide a generic system to declare options on arbitrary structs
43  * ("objects"). An option can have a help text, a type and a range of possible
44  * values. Options may then be enumerated, read and written to.
45  *
46  * @section avoptions_implement Implementing AVOptions
47  * This section describes how to add AVOptions capabilities to a struct.
48  *
49  * All AVOptions-related information is stored in an AVClass. Therefore
50  * the first member of the struct should be a pointer to an AVClass describing it.
51  * The option field of the AVClass must be set to a NULL-terminated static array
52  * of AVOptions. Each AVOption must have a non-empty name, a type, a default
53  * value and for number-type AVOptions also a range of allowed values. It must
54  * also declare an offset in bytes from the start of the struct, where the field
55  * associated with this AVOption is located. Other fields in the AVOption struct
56  * should also be set when applicable, but are not required.
57  *
58  * The following example illustrates an AVOptions-enabled struct:
59  * @code
60  * typedef struct test_struct {
61  * const AVClass *class;
62  * int int_opt;
63  * char *str_opt;
64  * uint8_t *bin_opt;
65  * int bin_len;
66  * } test_struct;
67  *
68  * static const AVOption test_options[] = {
69  * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
70  * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
71  * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
72  * AV_OPT_TYPE_STRING },
73  * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
74  * AV_OPT_TYPE_BINARY },
75  * { NULL },
76  * };
77  *
78  * static const AVClass test_class = {
79  * .class_name = "test class",
80  * .item_name = av_default_item_name,
81  * .option = test_options,
82  * .version = LIBAVUTIL_VERSION_INT,
83  * };
84  * @endcode
85  *
86  * Next, when allocating your struct, you must ensure that the AVClass pointer
87  * is set to the correct value. Then, av_opt_set_defaults() can be called to
88  * initialize defaults. After that the struct is ready to be used with the
89  * AVOptions API.
90  *
91  * When cleaning up, you may use the av_opt_free() function to automatically
92  * free all the allocated string and binary options.
93  *
94  * Continuing with the above example:
95  *
96  * @code
97  * test_struct *alloc_test_struct(void)
98  * {
99  * test_struct *ret = av_mallocz(sizeof(*ret));
100  * ret->class = &test_class;
101  * av_opt_set_defaults(ret);
102  * return ret;
103  * }
104  * void free_test_struct(test_struct **foo)
105  * {
106  * av_opt_free(*foo);
107  * av_freep(foo);
108  * }
109  * @endcode
110  *
111  * @subsection avoptions_implement_nesting Nesting
112  * It may happen that an AVOptions-enabled struct contains another
113  * AVOptions-enabled struct as a member (e.g. AVCodecContext in
114  * libavcodec exports generic options, while its priv_data field exports
115  * codec-specific options). In such a case, it is possible to set up the
116  * parent struct to export a child's options. To do that, simply
117  * implement AVClass.child_next() and AVClass.child_class_iterate() in the
118  * parent struct's AVClass.
119  * Assuming that the test_struct from above now also contains a
120  * child_struct field:
121  *
122  * @code
123  * typedef struct child_struct {
124  * AVClass *class;
125  * int flags_opt;
126  * } child_struct;
127  * static const AVOption child_opts[] = {
128  * { "test_flags", "This is a test option of flags type.",
129  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
130  * { NULL },
131  * };
132  * static const AVClass child_class = {
133  * .class_name = "child class",
134  * .item_name = av_default_item_name,
135  * .option = child_opts,
136  * .version = LIBAVUTIL_VERSION_INT,
137  * };
138  *
139  * void *child_next(void *obj, void *prev)
140  * {
141  * test_struct *t = obj;
142  * if (!prev && t->child_struct)
143  * return t->child_struct;
144  * return NULL
145  * }
146  * const AVClass child_class_iterate(void **iter)
147  * {
148  * const AVClass *c = *iter ? NULL : &child_class;
149  * *iter = (void*)(uintptr_t)c;
150  * return c;
151  * }
152  * @endcode
153  * Putting child_next() and child_class_iterate() as defined above into
154  * test_class will now make child_struct's options accessible through
155  * test_struct (again, proper setup as described above needs to be done on
156  * child_struct right after it is created).
157  *
158  * From the above example it might not be clear why both child_next()
159  * and child_class_iterate() are needed. The distinction is that child_next()
160  * iterates over actually existing objects, while child_class_iterate()
161  * iterates over all possible child classes. E.g. if an AVCodecContext
162  * was initialized to use a codec which has private options, then its
163  * child_next() will return AVCodecContext.priv_data and finish
164  * iterating. OTOH child_class_iterate() on AVCodecContext.av_class will
165  * iterate over all available codecs with private options.
166  *
167  * @subsection avoptions_implement_named_constants Named constants
168  * It is possible to create named constants for options. Simply set the unit
169  * field of the option the constants should apply to a string and
170  * create the constants themselves as options of type AV_OPT_TYPE_CONST
171  * with their unit field set to the same string.
172  * Their default_val field should contain the value of the named
173  * constant.
174  * For example, to add some named constants for the test_flags option
175  * above, put the following into the child_opts array:
176  * @code
177  * { "test_flags", "This is a test option of flags type.",
178  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
179  * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
180  * @endcode
181  *
182  * @section avoptions_use Using AVOptions
183  * This section deals with accessing options in an AVOptions-enabled struct.
184  * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
185  * AVFormatContext in libavformat.
186  *
187  * @subsection avoptions_use_examine Examining AVOptions
188  * The basic functions for examining options are av_opt_next(), which iterates
189  * over all options defined for one object, and av_opt_find(), which searches
190  * for an option with the given name.
191  *
192  * The situation is more complicated with nesting. An AVOptions-enabled struct
193  * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
194  * to av_opt_find() will make the function search children recursively.
195  *
196  * For enumerating there are basically two cases. The first is when you want to
197  * get all options that may potentially exist on the struct and its children
198  * (e.g. when constructing documentation). In that case you should call
199  * av_opt_child_class_iterate() recursively on the parent struct's AVClass. The
200  * second case is when you have an already initialized struct with all its
201  * children and you want to get all options that can be actually written or read
202  * from it. In that case you should call av_opt_child_next() recursively (and
203  * av_opt_next() on each result).
204  *
205  * @subsection avoptions_use_get_set Reading and writing AVOptions
206  * When setting options, you often have a string read directly from the
207  * user. In such a case, simply passing it to av_opt_set() is enough. For
208  * non-string type options, av_opt_set() will parse the string according to the
209  * option type.
210  *
211  * Similarly av_opt_get() will read any option type and convert it to a string
212  * which will be returned. Do not forget that the string is allocated, so you
213  * have to free it with av_free().
214  *
215  * In some cases it may be more convenient to put all options into an
216  * AVDictionary and call av_opt_set_dict() on it. A specific case of this
217  * are the format/codec open functions in lavf/lavc which take a dictionary
218  * filled with option as a parameter. This makes it possible to set some options
219  * that cannot be set otherwise, since e.g. the input file format is not known
220  * before the file is actually opened.
221  */
222 
231  AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
235  AV_OPT_TYPE_IMAGE_SIZE, ///< offset must point to two consecutive integers
238  AV_OPT_TYPE_VIDEO_RATE, ///< offset must point to AVRational
243 };
244 
245 /**
246  * AVOption
247  */
248 typedef struct AVOption {
249  const char *name;
250 
251  /**
252  * short English help text
253  * @todo What about other languages?
254  */
255  const char *help;
256 
257  /**
258  * The offset relative to the context structure where the option
259  * value is stored. It should be 0 for named constants.
260  */
261  int offset;
263 
264  /**
265  * the default value for scalar options
266  */
267  union {
268  int64_t i64;
269  double dbl;
270  const char *str;
271  /* TODO those are unused now */
273  } default_val;
274  double min; ///< minimum valid value for the option
275  double max; ///< maximum valid value for the option
276 
277  int flags;
278 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
279 #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
280 #define AV_OPT_FLAG_AUDIO_PARAM 8
281 #define AV_OPT_FLAG_VIDEO_PARAM 16
282 #define AV_OPT_FLAG_SUBTITLE_PARAM 32
283 /**
284  * The option is intended for exporting values to the caller.
285  */
286 #define AV_OPT_FLAG_EXPORT 64
287 /**
288  * The option may not be set through the AVOptions API, only read.
289  * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
290  */
291 #define AV_OPT_FLAG_READONLY 128
292 #define AV_OPT_FLAG_BSF_PARAM (1<<8) ///< a generic parameter which can be set by the user for bit stream filtering
293 #define AV_OPT_FLAG_RUNTIME_PARAM (1<<15) ///< a generic parameter which can be set by the user at runtime
294 #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
295 #define AV_OPT_FLAG_DEPRECATED (1<<17) ///< set if option is deprecated, users should refer to AVOption.help text for more information
296 #define AV_OPT_FLAG_CHILD_CONSTS (1<<18) ///< set if option constants can also reside in child objects
297 //FIXME think about enc-audio, ... style flags
298 
299  /**
300  * The logical unit to which the option belongs. Non-constant
301  * options and corresponding named constants share the same
302  * unit. May be NULL.
303  */
304  const char *unit;
305 } AVOption;
306 
307 /**
308  * A single allowed range of values, or a single allowed value.
309  */
310 typedef struct AVOptionRange {
311  const char *str;
312  /**
313  * Value range.
314  * For string ranges this represents the min/max length.
315  * For dimensions this represents the min/max pixel count or width/height in multi-component case.
316  */
317  double value_min, value_max;
318  /**
319  * Value's component range.
320  * For string this represents the unicode range for chars, 0-127 limits to ASCII.
321  */
322  double component_min, component_max;
323  /**
324  * Range flag.
325  * If set to 1 the struct encodes a range, if set to 0 a single value.
326  */
327  int is_range;
328 } AVOptionRange;
329 
330 /**
331  * List of AVOptionRange structs.
332  */
333 typedef struct AVOptionRanges {
334  /**
335  * Array of option ranges.
336  *
337  * Most of option types use just one component.
338  * Following describes multi-component option types:
339  *
340  * AV_OPT_TYPE_IMAGE_SIZE:
341  * component index 0: range of pixel count (width * height).
342  * component index 1: range of width.
343  * component index 2: range of height.
344  *
345  * @note To obtain multi-component version of this structure, user must
346  * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
347  * av_opt_query_ranges_default function.
348  *
349  * Multi-component range can be read as in following example:
350  *
351  * @code
352  * int range_index, component_index;
353  * AVOptionRanges *ranges;
354  * AVOptionRange *range[3]; //may require more than 3 in the future.
355  * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
356  * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
357  * for (component_index = 0; component_index < ranges->nb_components; component_index++)
358  * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
359  * //do something with range here.
360  * }
361  * av_opt_freep_ranges(&ranges);
362  * @endcode
363  */
365  /**
366  * Number of ranges per component.
367  */
369  /**
370  * Number of componentes.
371  */
374 
375 /**
376  * Show the obj options.
377  *
378  * @param req_flags requested flags for the options to show. Show only the
379  * options for which it is opt->flags & req_flags.
380  * @param rej_flags rejected flags for the options to show. Show only the
381  * options for which it is !(opt->flags & req_flags).
382  * @param av_log_obj log context to use for showing the options
383  */
384 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
385 
386 /**
387  * Set the values of all AVOption fields to their default values.
388  *
389  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
390  */
391 void av_opt_set_defaults(void *s);
392 
393 /**
394  * Set the values of all AVOption fields to their default values. Only these
395  * AVOption fields for which (opt->flags & mask) == flags will have their
396  * default applied to s.
397  *
398  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
399  * @param mask combination of AV_OPT_FLAG_*
400  * @param flags combination of AV_OPT_FLAG_*
401  */
402 void av_opt_set_defaults2(void *s, int mask, int flags);
403 
404 /**
405  * Parse the key/value pairs list in opts. For each key/value pair
406  * found, stores the value in the field in ctx that is named like the
407  * key. ctx must be an AVClass context, storing is done using
408  * AVOptions.
409  *
410  * @param opts options string to parse, may be NULL
411  * @param key_val_sep a 0-terminated list of characters used to
412  * separate key from value
413  * @param pairs_sep a 0-terminated list of characters used to separate
414  * two pairs from each other
415  * @return the number of successfully set key/value pairs, or a negative
416  * value corresponding to an AVERROR code in case of error:
417  * AVERROR(EINVAL) if opts cannot be parsed,
418  * the error code issued by av_opt_set() if a key/value pair
419  * cannot be set
420  */
421 int av_set_options_string(void *ctx, const char *opts,
422  const char *key_val_sep, const char *pairs_sep);
423 
424 /**
425  * Parse the key-value pairs list in opts. For each key=value pair found,
426  * set the value of the corresponding option in ctx.
427  *
428  * @param ctx the AVClass object to set options on
429  * @param opts the options string, key-value pairs separated by a
430  * delimiter
431  * @param shorthand a NULL-terminated array of options names for shorthand
432  * notation: if the first field in opts has no key part,
433  * the key is taken from the first element of shorthand;
434  * then again for the second, etc., until either opts is
435  * finished, shorthand is finished or a named option is
436  * found; after that, all options must be named
437  * @param key_val_sep a 0-terminated list of characters used to separate
438  * key from value, for example '='
439  * @param pairs_sep a 0-terminated list of characters used to separate
440  * two pairs from each other, for example ':' or ','
441  * @return the number of successfully set key=value pairs, or a negative
442  * value corresponding to an AVERROR code in case of error:
443  * AVERROR(EINVAL) if opts cannot be parsed,
444  * the error code issued by av_set_string3() if a key/value pair
445  * cannot be set
446  *
447  * Options names must use only the following characters: a-z A-Z 0-9 - . / _
448  * Separators must use characters distinct from option names and from each
449  * other.
450  */
451 int av_opt_set_from_string(void *ctx, const char *opts,
452  const char *const *shorthand,
453  const char *key_val_sep, const char *pairs_sep);
454 /**
455  * Free all allocated objects in obj.
456  */
457 void av_opt_free(void *obj);
458 
459 /**
460  * Check whether a particular flag is set in a flags field.
461  *
462  * @param field_name the name of the flag field option
463  * @param flag_name the name of the flag to check
464  * @return non-zero if the flag is set, zero if the flag isn't set,
465  * isn't of the right type, or the flags field doesn't exist.
466  */
467 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
468 
469 /**
470  * Set all the options from a given dictionary on an object.
471  *
472  * @param obj a struct whose first element is a pointer to AVClass
473  * @param options options to process. This dictionary will be freed and replaced
474  * by a new one containing all options not found in obj.
475  * Of course this new dictionary needs to be freed by caller
476  * with av_dict_free().
477  *
478  * @return 0 on success, a negative AVERROR if some option was found in obj,
479  * but could not be set.
480  *
481  * @see av_dict_copy()
482  */
483 int av_opt_set_dict(void *obj, struct AVDictionary **options);
484 
485 
486 /**
487  * Set all the options from a given dictionary on an object.
488  *
489  * @param obj a struct whose first element is a pointer to AVClass
490  * @param options options to process. This dictionary will be freed and replaced
491  * by a new one containing all options not found in obj.
492  * Of course this new dictionary needs to be freed by caller
493  * with av_dict_free().
494  * @param search_flags A combination of AV_OPT_SEARCH_*.
495  *
496  * @return 0 on success, a negative AVERROR if some option was found in obj,
497  * but could not be set.
498  *
499  * @see av_dict_copy()
500  */
501 int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
502 
503 /**
504  * Extract a key-value pair from the beginning of a string.
505  *
506  * @param ropts pointer to the options string, will be updated to
507  * point to the rest of the string (one of the pairs_sep
508  * or the final NUL)
509  * @param key_val_sep a 0-terminated list of characters used to separate
510  * key from value, for example '='
511  * @param pairs_sep a 0-terminated list of characters used to separate
512  * two pairs from each other, for example ':' or ','
513  * @param flags flags; see the AV_OPT_FLAG_* values below
514  * @param rkey parsed key; must be freed using av_free()
515  * @param rval parsed value; must be freed using av_free()
516  *
517  * @return >=0 for success, or a negative value corresponding to an
518  * AVERROR code in case of error; in particular:
519  * AVERROR(EINVAL) if no key is present
520  *
521  */
522 int av_opt_get_key_value(const char **ropts,
523  const char *key_val_sep, const char *pairs_sep,
524  unsigned flags,
525  char **rkey, char **rval);
526 
527 enum {
528 
529  /**
530  * Accept to parse a value without a key; the key will then be returned
531  * as NULL.
532  */
534 };
535 
536 /**
537  * @defgroup opt_eval_funcs Evaluating option strings
538  * @{
539  * This group of functions can be used to evaluate option strings
540  * and get numbers out of them. They do the same thing as av_opt_set(),
541  * except the result is written into the caller-supplied pointer.
542  *
543  * @param obj a struct whose first element is a pointer to AVClass.
544  * @param o an option for which the string is to be evaluated.
545  * @param val string to be evaluated.
546  * @param *_out value of the string will be written here.
547  *
548  * @return 0 on success, a negative number on failure.
549  */
550 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
551 int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
552 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
553 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
554 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
555 int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
556 /**
557  * @}
558  */
559 
560 #define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
561  given object first. */
562 /**
563  * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
564  * instead of a required pointer to a struct containing AVClass. This is
565  * useful for searching for options without needing to allocate the corresponding
566  * object.
567  */
568 #define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
570 /**
571  * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
572  * rather than returning an empty string.
573  */
574 #define AV_OPT_ALLOW_NULL (1 << 2)
576 /**
577  * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
578  * one component for certain option types.
579  * @see AVOptionRanges for details.
580  */
581 #define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
583 /**
584  * Look for an option in an object. Consider only options which
585  * have all the specified flags set.
586  *
587  * @param[in] obj A pointer to a struct whose first element is a
588  * pointer to an AVClass.
589  * Alternatively a double pointer to an AVClass, if
590  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
591  * @param[in] name The name of the option to look for.
592  * @param[in] unit When searching for named constants, name of the unit
593  * it belongs to.
594  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
595  * @param search_flags A combination of AV_OPT_SEARCH_*.
596  *
597  * @return A pointer to the option found, or NULL if no option
598  * was found.
599  *
600  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
601  * directly with av_opt_set(). Use special calls which take an options
602  * AVDictionary (e.g. avformat_open_input()) to set options found with this
603  * flag.
604  */
605 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
606  int opt_flags, int search_flags);
607 
608 /**
609  * Look for an option in an object. Consider only options which
610  * have all the specified flags set.
611  *
612  * @param[in] obj A pointer to a struct whose first element is a
613  * pointer to an AVClass.
614  * Alternatively a double pointer to an AVClass, if
615  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
616  * @param[in] name The name of the option to look for.
617  * @param[in] unit When searching for named constants, name of the unit
618  * it belongs to.
619  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
620  * @param search_flags A combination of AV_OPT_SEARCH_*.
621  * @param[out] target_obj if non-NULL, an object to which the option belongs will be
622  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
623  * in search_flags. This parameter is ignored if search_flags contain
624  * AV_OPT_SEARCH_FAKE_OBJ.
625  *
626  * @return A pointer to the option found, or NULL if no option
627  * was found.
628  */
629 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
630  int opt_flags, int search_flags, void **target_obj);
631 
632 /**
633  * Iterate over all AVOptions belonging to obj.
634  *
635  * @param obj an AVOptions-enabled struct or a double pointer to an
636  * AVClass describing it.
637  * @param prev result of the previous call to av_opt_next() on this object
638  * or NULL
639  * @return next AVOption or NULL
640  */
641 const AVOption *av_opt_next(const void *obj, const AVOption *prev);
642 
643 /**
644  * Iterate over AVOptions-enabled children of obj.
645  *
646  * @param prev result of a previous call to this function or NULL
647  * @return next AVOptions-enabled child or NULL
648  */
649 void *av_opt_child_next(void *obj, void *prev);
650 
651 #if FF_API_CHILD_CLASS_NEXT
652 /**
653  * Iterate over potential AVOptions-enabled children of parent.
654  *
655  * @param prev result of a previous call to this function or NULL
656  * @return AVClass corresponding to next potential child or NULL
657  *
658  * @deprecated use av_opt_child_class_iterate
659  */
661 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
662 #endif
663 
664 /**
665  * Iterate over potential AVOptions-enabled children of parent.
666  *
667  * @param iter a pointer where iteration state is stored.
668  * @return AVClass corresponding to next potential child or NULL
669  */
670 const AVClass *av_opt_child_class_iterate(const AVClass *parent, void **iter);
671 
672 /**
673  * @defgroup opt_set_funcs Option setting functions
674  * @{
675  * Those functions set the field of obj with the given name to value.
676  *
677  * @param[in] obj A struct whose first element is a pointer to an AVClass.
678  * @param[in] name the name of the field to set
679  * @param[in] val The value to set. In case of av_opt_set() if the field is not
680  * of a string type, then the given string is parsed.
681  * SI postfixes and some named scalars are supported.
682  * If the field is of a numeric type, it has to be a numeric or named
683  * scalar. Behavior with more than one scalar and +- infix operators
684  * is undefined.
685  * If the field is of a flags type, it has to be a sequence of numeric
686  * scalars or named flags separated by '+' or '-'. Prefixing a flag
687  * with '+' causes it to be set without affecting the other flags;
688  * similarly, '-' unsets a flag.
689  * If the field is of a dictionary type, it has to be a ':' separated list of
690  * key=value parameters. Values containing ':' special characters must be
691  * escaped.
692  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
693  * is passed here, then the option may be set on a child of obj.
694  *
695  * @return 0 if the value has been set, or an AVERROR code in case of
696  * error:
697  * AVERROR_OPTION_NOT_FOUND if no matching option exists
698  * AVERROR(ERANGE) if the value is out of range
699  * AVERROR(EINVAL) if the value is not valid
700  */
701 int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
702 int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
703 int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
704 int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
705 int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
706 int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
707 int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
708 int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
709 int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
710 int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
711 /**
712  * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
713  * caller still owns val is and responsible for freeing it.
714  */
715 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
716 
717 /**
718  * Set a binary option to an integer list.
719  *
720  * @param obj AVClass object to set options on
721  * @param name name of the binary option
722  * @param val pointer to an integer list (must have the correct type with
723  * regard to the contents of the list)
724  * @param term list terminator (usually 0 or -1)
725  * @param flags search flags
726  */
727 #define av_opt_set_int_list(obj, name, val, term, flags) \
728  (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
729  AVERROR(EINVAL) : \
730  av_opt_set_bin(obj, name, (const uint8_t *)(val), \
731  av_int_list_length(val, term) * sizeof(*(val)), flags))
732 
733 /**
734  * @}
735  */
736 
737 /**
738  * @defgroup opt_get_funcs Option getting functions
739  * @{
740  * Those functions get a value of the option with the given name from an object.
741  *
742  * @param[in] obj a struct whose first element is a pointer to an AVClass.
743  * @param[in] name name of the option to get.
744  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
745  * is passed here, then the option may be found in a child of obj.
746  * @param[out] out_val value of the option will be written here
747  * @return >=0 on success, a negative error code otherwise
748  */
749 /**
750  * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
751  *
752  * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the
753  * option is of type AV_OPT_TYPE_STRING, AV_OPT_TYPE_BINARY or AV_OPT_TYPE_DICT
754  * and is set to NULL, *out_val will be set to NULL instead of an allocated
755  * empty string.
756  */
757 int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
758 int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
759 int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
760 int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
761 int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
762 int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
763 int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
764 int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
765 int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
766 /**
767  * @param[out] out_val The returned dictionary is a copy of the actual value and must
768  * be freed with av_dict_free() by the caller
769  */
770 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
771 /**
772  * @}
773  */
774 /**
775  * Gets a pointer to the requested field in a struct.
776  * This function allows accessing a struct even when its fields are moved or
777  * renamed since the application making the access has been compiled,
778  *
779  * @returns a pointer to the field, it can be cast to the correct type and read
780  * or written to.
781  */
782 void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
783 
784 /**
785  * Free an AVOptionRanges struct and set it to NULL.
786  */
787 void av_opt_freep_ranges(AVOptionRanges **ranges);
788 
789 /**
790  * Get a list of allowed ranges for the given option.
791  *
792  * The returned list may depend on other fields in obj like for example profile.
793  *
794  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
795  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
796  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
797  *
798  * The result must be freed with av_opt_freep_ranges.
799  *
800  * @return number of compontents returned on success, a negative errro code otherwise
801  */
802 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
803 
804 /**
805  * Copy options from src object into dest object.
806  *
807  * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
808  * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
809  *
810  * @param dest Object to copy from
811  * @param src Object to copy into
812  * @return 0 on success, negative on error
813  */
814 int av_opt_copy(void *dest, const void *src);
815 
816 /**
817  * Get a default list of allowed ranges for the given option.
818  *
819  * This list is constructed without using the AVClass.query_ranges() callback
820  * and can be used as fallback from within the callback.
821  *
822  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
823  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
824  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
825  *
826  * The result must be freed with av_opt_free_ranges.
827  *
828  * @return number of compontents returned on success, a negative errro code otherwise
829  */
830 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
831 
832 /**
833  * Check if given option is set to its default value.
834  *
835  * Options o must belong to the obj. This function must not be called to check child's options state.
836  * @see av_opt_is_set_to_default_by_name().
837  *
838  * @param obj AVClass object to check option on
839  * @param o option to be checked
840  * @return >0 when option is set to its default,
841  * 0 when option is not set its default,
842  * <0 on error
843  */
844 int av_opt_is_set_to_default(void *obj, const AVOption *o);
845 
846 /**
847  * Check if given option is set to its default value.
848  *
849  * @param obj AVClass object to check option on
850  * @param name option name
851  * @param search_flags combination of AV_OPT_SEARCH_*
852  * @return >0 when option is set to its default,
853  * 0 when option is not set its default,
854  * <0 on error
855  */
856 int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
857 
858 
859 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
860 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
862 /**
863  * Serialize object's options.
864  *
865  * Create a string containing object's serialized options.
866  * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
867  * A key/value or pairs separator occurring in the serialized value or
868  * name string are escaped through the av_escape() function.
869  *
870  * @param[in] obj AVClass object to serialize
871  * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
872  * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
873  * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
874  * Buffer must be freed by the caller when is no longer needed.
875  * @param[in] key_val_sep character used to separate key from value
876  * @param[in] pairs_sep character used to separate two pairs from each other
877  * @return >= 0 on success, negative on error
878  * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
879  */
880 int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
881  const char key_val_sep, const char pairs_sep);
882 /**
883  * @}
884  */
885 
886 #endif /* AVUTIL_OPT_H */
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
Definition: opt.c:1031
A single allowed range of values, or a single allowed value.
Definition: opt.h:310
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
AVOption.
Definition: opt.h:248
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:596
void * av_opt_child_next(void *obj, void *prev)
Iterate over AVOptions-enabled children of obj.
Definition: opt.c:1711
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1357
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.
Definition: opt.c:1478
Convenience header that includes libavutil&#39;s core.
int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int size, int search_flags)
Definition: opt.c:601
const char * key
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:936
int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer, const char key_val_sep, const char pairs_sep)
Serialize object&#39;s options.
Definition: opt.c:2080
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
Definition: opt.c:725
AVOptionType
Definition: opt.h:223
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.
Definition: opt.c:2068
AVRational q
Definition: opt.h:272
int av_opt_is_set_to_default(void *obj, const AVOption *o)
Check if given option is set to its default value.
Definition: opt.c:1957
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:970
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.
Definition: opt.c:1558
Public dictionary API.
const char * name
Definition: opt.h:249
uint8_t
AVOptionRange ** range
Array of option ranges.
Definition: opt.h:364
const char * help
short English help text
Definition: opt.h:255
const char * str
Definition: opt.h:270
int av_opt_eval_int64(void *obj, const AVOption *o, const char *val, int64_t *int64_out)
int av_opt_set_double(void *obj, const char *name, double val, int search_flags)
Definition: opt.c:591
attribute_deprecated const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
Definition: opt.c:1721
ptrdiff_t size
Definition: opengl_enc.c:100
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:653
#define src
Definition: vp8dsp.c:254
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
Definition: opt.c:1004
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
Definition: opt.c:699
void * av_opt_ptr(const AVClass *avclass, void *obj, const char *name)
Gets a pointer to the requested field in a struct.
Definition: opt.c:1745
static const uint16_t mask[17]
Definition: lzw.c:38
double max
maximum valid value for the option
Definition: opt.h:275
int av_opt_eval_flags(void *obj, const AVOption *o, const char *val, int *flags_out)
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:586
const AVOption * av_opt_next(const void *obj, const AVOption *prev)
Iterate over all AVOptions belonging to obj.
Definition: opt.c:45
Libavutil version macros.
const AVOption * av_opt_find(void *obj, const char *name, const char *unit, int opt_flags, int search_flags)
Look for an option in an object.
Definition: opt.c:1660
int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out)
Accept to parse a value without a key; the key will then be returned as NULL.
Definition: opt.h:533
AVDictionary * opts
Definition: movenc.c:50
int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt)
Definition: opt.c:1009
const char * str
Definition: opt.h:311
uint8_t w
Definition: llviddspenc.c:38
AVFormatContext * ctx
Definition: movenc.c:48
const char * unit
The logical unit to which the option belongs.
Definition: opt.h:304
double component_min
Value&#39;s component range.
Definition: opt.h:322
int av_opt_eval_q(void *obj, const AVOption *o, const char *val, AVRational *q_out)
int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags)
Definition: opt.c:709
double min
minimum valid value for the option
Definition: opt.h:274
#define s(width, name)
Definition: cbs_vp9.c:257
void av_opt_set_defaults2(void *s, int mask, int flags)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1362
int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags)
Set all the options from a given dictionary on an object.
Definition: opt.c:1630
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:231
int flags
Definition: opt.h:277
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.
Definition: opt.c:1866
int is_range
Range flag.
Definition: opt.h:327
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
Definition: opt.c:912
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
Definition: opt.c:1938
int offset
The offset relative to the context structure where the option value is stored.
Definition: opt.h:261
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int av_opt_set_dict(void *obj, struct AVDictionary **options)
Set all the options from a given dictionary on an object.
Definition: opt.c:1655
int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
Show the obj options.
Definition: opt.c:1345
union AVOption::@314 default_val
the default value for scalar options
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
Definition: opt.c:1014
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
const AVClass * av_opt_child_class_iterate(const AVClass *parent, void **iter)
Iterate over potential AVOptions-enabled children of parent.
Definition: opt.c:1730
double dbl
Definition: opt.h:269
offset must point to AVRational
Definition: opt.h:238
int av_opt_eval_int(void *obj, const AVOption *o, const char *val, int *int_out)
offset must point to two consecutive integers
Definition: opt.h:235
#define attribute_deprecated
Definition: attributes.h:100
void av_opt_free(void *obj)
Free all allocated objects in obj.
Definition: opt.c:1610
const OptionDef options[]
Definition: ffmpeg_opt.c:3400
int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags)
Get a list of allowed ranges for the given option.
Definition: opt.c:1845
double value_min
Value range.
Definition: opt.h:317
Utilties for rational number calculation.
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
Definition: opt.c:924
int av_opt_copy(void *dest, const void *src)
Copy options from src object into dest object.
Definition: opt.c:1788
int nb_ranges
Number of ranges per component.
Definition: opt.h:368
List of AVOptionRange structs.
Definition: opt.h:333
pixel format definitions
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:779
enum AVOptionType type
Definition: opt.h:262
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.
Definition: opt.c:1536
int64_t i64
Definition: opt.h:268
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.
Definition: opt.c:1048
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.
Definition: opt.c:1666
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
Definition: opt.c:704
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
static double val(void *priv, double ch)
Definition: aeval.c:76
int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
Definition: opt.c:631
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:465
GLuint buffer
Definition: opengl_enc.c:101
const char * name
Definition: opengl_enc.c:102
int nb_components
Number of componentes.
Definition: opt.h:372
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
Definition: opt.c:952