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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 "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  * 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_malloc(sizeof(*ret));
100  * ret->class = &test_class;
101  * av_opt_set_defaults(ret);
102  * return ret;
103  * }
104  * void free_test_struct(test_struct **foo)
105  * {
106  * av_opt_free(*foo);
107  * av_freep(foo);
108  * }
109  * @endcode
110  *
111  * @subsection avoptions_implement_nesting Nesting
112  * It may happen that an AVOptions-enabled struct contains another
113  * AVOptions-enabled struct as a member (e.g. AVCodecContext in
114  * libavcodec exports generic options, while its priv_data field exports
115  * codec-specific options). In such a case, it is possible to set up the
116  * parent struct to export a child's options. To do that, simply
117  * implement AVClass.child_next() and AVClass.child_class_next() in the
118  * parent struct's AVClass.
119  * Assuming that the test_struct from above now also contains a
120  * child_struct field:
121  *
122  * @code
123  * typedef struct child_struct {
124  * AVClass *class;
125  * int flags_opt;
126  * } child_struct;
127  * static const AVOption child_opts[] = {
128  * { "test_flags", "This is a test option of flags type.",
129  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
130  * { NULL },
131  * };
132  * static const AVClass child_class = {
133  * .class_name = "child class",
134  * .item_name = av_default_item_name,
135  * .option = child_opts,
136  * .version = LIBAVUTIL_VERSION_INT,
137  * };
138  *
139  * void *child_next(void *obj, void *prev)
140  * {
141  * test_struct *t = obj;
142  * if (!prev && t->child_struct)
143  * return t->child_struct;
144  * return NULL
145  * }
146  * const AVClass child_class_next(const AVClass *prev)
147  * {
148  * return prev ? NULL : &child_class;
149  * }
150  * @endcode
151  * Putting child_next() and child_class_next() as defined above into
152  * test_class will now make child_struct's options accessible through
153  * test_struct (again, proper setup as described above needs to be done on
154  * child_struct right after it is created).
155  *
156  * From the above example it might not be clear why both child_next()
157  * and child_class_next() are needed. The distinction is that child_next()
158  * iterates over actually existing objects, while child_class_next()
159  * iterates over all possible child classes. E.g. if an AVCodecContext
160  * was initialized to use a codec which has private options, then its
161  * child_next() will return AVCodecContext.priv_data and finish
162  * iterating. OTOH child_class_next() on AVCodecContext.av_class will
163  * iterate over all available codecs with private options.
164  *
165  * @subsection avoptions_implement_named_constants Named constants
166  * It is possible to create named constants for options. Simply set the unit
167  * field of the option the constants should apply to a string and
168  * create the constants themselves as options of type AV_OPT_TYPE_CONST
169  * with their unit field set to the same string.
170  * Their default_val field should contain the value of the named
171  * constant.
172  * For example, to add some named constants for the test_flags option
173  * above, put the following into the child_opts array:
174  * @code
175  * { "test_flags", "This is a test option of flags type.",
176  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
177  * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
178  * @endcode
179  *
180  * @section avoptions_use Using AVOptions
181  * This section deals with accessing options in an AVOptions-enabled struct.
182  * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
183  * AVFormatContext in libavformat.
184  *
185  * @subsection avoptions_use_examine Examining AVOptions
186  * The basic functions for examining options are av_opt_next(), which iterates
187  * over all options defined for one object, and av_opt_find(), which searches
188  * for an option with the given name.
189  *
190  * The situation is more complicated with nesting. An AVOptions-enabled struct
191  * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
192  * to av_opt_find() will make the function search children recursively.
193  *
194  * For enumerating there are basically two cases. The first is when you want to
195  * get all options that may potentially exist on the struct and its children
196  * (e.g. when constructing documentation). In that case you should call
197  * av_opt_child_class_next() recursively on the parent struct's AVClass. The
198  * second case is when you have an already initialized struct with all its
199  * children and you want to get all options that can be actually written or read
200  * from it. In that case you should call av_opt_child_next() recursively (and
201  * av_opt_next() on each result).
202  *
203  * @subsection avoptions_use_get_set Reading and writing AVOptions
204  * When setting options, you often have a string read directly from the
205  * user. In such a case, simply passing it to av_opt_set() is enough. For
206  * non-string type options, av_opt_set() will parse the string according to the
207  * option type.
208  *
209  * Similarly av_opt_get() will read any option type and convert it to a string
210  * which will be returned. Do not forget that the string is allocated, so you
211  * have to free it with av_free().
212  *
213  * In some cases it may be more convenient to put all options into an
214  * AVDictionary and call av_opt_set_dict() on it. A specific case of this
215  * are the format/codec open functions in lavf/lavc which take a dictionary
216  * filled with option as a parameter. This makes it possible to set some options
217  * that cannot be set otherwise, since e.g. the input file format is not known
218  * before the file is actually opened.
219  */
220 
229  AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
232  AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers
233  AV_OPT_TYPE_PIXEL_FMT = MKBETAG('P','F','M','T'),
234  AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'),
235  AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational
236  AV_OPT_TYPE_DURATION = MKBETAG('D','U','R',' '),
237  AV_OPT_TYPE_COLOR = MKBETAG('C','O','L','R'),
239  AV_OPT_TYPE_BOOL = MKBETAG('B','O','O','L'),
240 };
241 
242 /**
243  * AVOption
244  */
245 typedef struct AVOption {
246  const char *name;
247 
248  /**
249  * short English help text
250  * @todo What about other languages?
251  */
252  const char *help;
253 
254  /**
255  * The offset relative to the context structure where the option
256  * value is stored. It should be 0 for named constants.
257  */
258  int offset;
260 
261  /**
262  * the default value for scalar options
263  */
264  union {
265  int64_t i64;
266  double dbl;
267  const char *str;
268  /* TODO those are unused now */
270  } default_val;
271  double min; ///< minimum valid value for the option
272  double max; ///< maximum valid value for the option
273 
274  int flags;
275 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
276 #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
277 #if FF_API_OPT_TYPE_METADATA
278 #define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
279 #endif
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 inteded 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_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
293 //FIXME think about enc-audio, ... style flags
294 
295  /**
296  * The logical unit to which the option belongs. Non-constant
297  * options and corresponding named constants share the same
298  * unit. May be NULL.
299  */
300  const char *unit;
301 } AVOption;
302 
303 /**
304  * A single allowed range of values, or a single allowed value.
305  */
306 typedef struct AVOptionRange {
307  const char *str;
308  /**
309  * Value range.
310  * For string ranges this represents the min/max length.
311  * For dimensions this represents the min/max pixel count or width/height in multi-component case.
312  */
314  /**
315  * Value's component range.
316  * For string this represents the unicode range for chars, 0-127 limits to ASCII.
317  */
319  /**
320  * Range flag.
321  * If set to 1 the struct encodes a range, if set to 0 a single value.
322  */
323  int is_range;
324 } AVOptionRange;
325 
326 /**
327  * List of AVOptionRange structs.
328  */
329 typedef struct AVOptionRanges {
330  /**
331  * Array of option ranges.
332  *
333  * Most of option types use just one component.
334  * Following describes multi-component option types:
335  *
336  * AV_OPT_TYPE_IMAGE_SIZE:
337  * component index 0: range of pixel count (width * height).
338  * component index 1: range of width.
339  * component index 2: range of height.
340  *
341  * @note To obtain multi-component version of this structure, user must
342  * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
343  * av_opt_query_ranges_default function.
344  *
345  * Multi-component range can be read as in following example:
346  *
347  * @code
348  * int range_index, component_index;
349  * AVOptionRanges *ranges;
350  * AVOptionRange *range[3]; //may require more than 3 in the future.
351  * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
352  * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
353  * for (component_index = 0; component_index < ranges->nb_components; component_index++)
354  * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
355  * //do something with range here.
356  * }
357  * av_opt_freep_ranges(&ranges);
358  * @endcode
359  */
361  /**
362  * Number of ranges per component.
363  */
365  /**
366  * Number of componentes.
367  */
370 
371 /**
372  * Show the obj options.
373  *
374  * @param req_flags requested flags for the options to show. Show only the
375  * options for which it is opt->flags & req_flags.
376  * @param rej_flags rejected flags for the options to show. Show only the
377  * options for which it is !(opt->flags & req_flags).
378  * @param av_log_obj log context to use for showing the options
379  */
380 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
381 
382 /**
383  * Set the values of all AVOption fields to their default values.
384  *
385  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
386  */
387 void av_opt_set_defaults(void *s);
388 
389 /**
390  * Set the values of all AVOption fields to their default values. Only these
391  * AVOption fields for which (opt->flags & mask) == flags will have their
392  * default applied to s.
393  *
394  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
395  * @param mask combination of AV_OPT_FLAG_*
396  * @param flags combination of AV_OPT_FLAG_*
397  */
398 void av_opt_set_defaults2(void *s, int mask, int flags);
399 
400 /**
401  * Parse the key/value pairs list in opts. For each key/value pair
402  * found, stores the value in the field in ctx that is named like the
403  * key. ctx must be an AVClass context, storing is done using
404  * AVOptions.
405  *
406  * @param opts options string to parse, may be NULL
407  * @param key_val_sep a 0-terminated list of characters used to
408  * separate key from value
409  * @param pairs_sep a 0-terminated list of characters used to separate
410  * two pairs from each other
411  * @return the number of successfully set key/value pairs, or a negative
412  * value corresponding to an AVERROR code in case of error:
413  * AVERROR(EINVAL) if opts cannot be parsed,
414  * the error code issued by av_opt_set() if a key/value pair
415  * cannot be set
416  */
417 int av_set_options_string(void *ctx, const char *opts,
418  const char *key_val_sep, const char *pairs_sep);
419 
420 /**
421  * Parse the key-value pairs list in opts. For each key=value pair found,
422  * set the value of the corresponding option in ctx.
423  *
424  * @param ctx the AVClass object to set options on
425  * @param opts the options string, key-value pairs separated by a
426  * delimiter
427  * @param shorthand a NULL-terminated array of options names for shorthand
428  * notation: if the first field in opts has no key part,
429  * the key is taken from the first element of shorthand;
430  * then again for the second, etc., until either opts is
431  * finished, shorthand is finished or a named option is
432  * found; after that, all options must be named
433  * @param key_val_sep a 0-terminated list of characters used to separate
434  * key from value, for example '='
435  * @param pairs_sep a 0-terminated list of characters used to separate
436  * two pairs from each other, for example ':' or ','
437  * @return the number of successfully set key=value pairs, or a negative
438  * value corresponding to an AVERROR code in case of error:
439  * AVERROR(EINVAL) if opts cannot be parsed,
440  * the error code issued by av_set_string3() if a key/value pair
441  * cannot be set
442  *
443  * Options names must use only the following characters: a-z A-Z 0-9 - . / _
444  * Separators must use characters distinct from option names and from each
445  * other.
446  */
447 int av_opt_set_from_string(void *ctx, const char *opts,
448  const char *const *shorthand,
449  const char *key_val_sep, const char *pairs_sep);
450 /**
451  * Free all allocated objects in obj.
452  */
453 void av_opt_free(void *obj);
454 
455 /**
456  * Check whether a particular flag is set in a flags field.
457  *
458  * @param field_name the name of the flag field option
459  * @param flag_name the name of the flag to check
460  * @return non-zero if the flag is set, zero if the flag isn't set,
461  * isn't of the right type, or the flags field doesn't exist.
462  */
463 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
464 
465 /**
466  * Set all the options from a given dictionary on an object.
467  *
468  * @param obj a struct whose first element is a pointer to AVClass
469  * @param options options to process. This dictionary will be freed and replaced
470  * by a new one containing all options not found in obj.
471  * Of course this new dictionary needs to be freed by caller
472  * with av_dict_free().
473  *
474  * @return 0 on success, a negative AVERROR if some option was found in obj,
475  * but could not be set.
476  *
477  * @see av_dict_copy()
478  */
479 int av_opt_set_dict(void *obj, struct AVDictionary **options);
480 
481 
482 /**
483  * Set all the options from a given dictionary on an object.
484  *
485  * @param obj a struct whose first element is a pointer to AVClass
486  * @param options options to process. This dictionary will be freed and replaced
487  * by a new one containing all options not found in obj.
488  * Of course this new dictionary needs to be freed by caller
489  * with av_dict_free().
490  * @param search_flags A combination of AV_OPT_SEARCH_*.
491  *
492  * @return 0 on success, a negative AVERROR if some option was found in obj,
493  * but could not be set.
494  *
495  * @see av_dict_copy()
496  */
497 int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
498 
499 /**
500  * Extract a key-value pair from the beginning of a string.
501  *
502  * @param ropts pointer to the options string, will be updated to
503  * point to the rest of the string (one of the pairs_sep
504  * or the final NUL)
505  * @param key_val_sep a 0-terminated list of characters used to separate
506  * key from value, for example '='
507  * @param pairs_sep a 0-terminated list of characters used to separate
508  * two pairs from each other, for example ':' or ','
509  * @param flags flags; see the AV_OPT_FLAG_* values below
510  * @param rkey parsed key; must be freed using av_free()
511  * @param rval parsed value; must be freed using av_free()
512  *
513  * @return >=0 for success, or a negative value corresponding to an
514  * AVERROR code in case of error; in particular:
515  * AVERROR(EINVAL) if no key is present
516  *
517  */
518 int av_opt_get_key_value(const char **ropts,
519  const char *key_val_sep, const char *pairs_sep,
520  unsigned flags,
521  char **rkey, char **rval);
522 
523 enum {
524 
525  /**
526  * Accept to parse a value without a key; the key will then be returned
527  * as NULL.
528  */
530 };
531 
532 /**
533  * @defgroup opt_eval_funcs Evaluating option strings
534  * @{
535  * This group of functions can be used to evaluate option strings
536  * and get numbers out of them. They do the same thing as av_opt_set(),
537  * except the result is written into the caller-supplied pointer.
538  *
539  * @param obj a struct whose first element is a pointer to AVClass.
540  * @param o an option for which the string is to be evaluated.
541  * @param val string to be evaluated.
542  * @param *_out value of the string will be written here.
543  *
544  * @return 0 on success, a negative number on failure.
545  */
546 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
547 int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
548 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
549 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
550 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
551 int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
552 /**
553  * @}
554  */
555 
556 #define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
557  given object first. */
558 /**
559  * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
560  * instead of a required pointer to a struct containing AVClass. This is
561  * useful for searching for options without needing to allocate the corresponding
562  * object.
563  */
564 #define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
566 /**
567  * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
568  * rather than returning an empty string.
569  */
570 #define AV_OPT_ALLOW_NULL (1 << 2)
572 /**
573  * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
574  * one component for certain option types.
575  * @see AVOptionRanges for details.
576  */
577 #define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
579 /**
580  * Look for an option in an object. Consider only options which
581  * have all the specified flags set.
582  *
583  * @param[in] obj A pointer to a struct whose first element is a
584  * pointer to an AVClass.
585  * Alternatively a double pointer to an AVClass, if
586  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
587  * @param[in] name The name of the option to look for.
588  * @param[in] unit When searching for named constants, name of the unit
589  * it belongs to.
590  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
591  * @param search_flags A combination of AV_OPT_SEARCH_*.
592  *
593  * @return A pointer to the option found, or NULL if no option
594  * was found.
595  *
596  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
597  * directly with av_opt_set(). Use special calls which take an options
598  * AVDictionary (e.g. avformat_open_input()) to set options found with this
599  * flag.
600  */
601 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
602  int opt_flags, int search_flags);
603 
604 /**
605  * Look for an option in an object. Consider only options which
606  * have all the specified flags set.
607  *
608  * @param[in] obj A pointer to a struct whose first element is a
609  * pointer to an AVClass.
610  * Alternatively a double pointer to an AVClass, if
611  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
612  * @param[in] name The name of the option to look for.
613  * @param[in] unit When searching for named constants, name of the unit
614  * it belongs to.
615  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
616  * @param search_flags A combination of AV_OPT_SEARCH_*.
617  * @param[out] target_obj if non-NULL, an object to which the option belongs will be
618  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
619  * in search_flags. This parameter is ignored if search_flags contain
620  * AV_OPT_SEARCH_FAKE_OBJ.
621  *
622  * @return A pointer to the option found, or NULL if no option
623  * was found.
624  */
625 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
626  int opt_flags, int search_flags, void **target_obj);
627 
628 /**
629  * Iterate over all AVOptions belonging to obj.
630  *
631  * @param obj an AVOptions-enabled struct or a double pointer to an
632  * AVClass describing it.
633  * @param prev result of the previous call to av_opt_next() on this object
634  * or NULL
635  * @return next AVOption or NULL
636  */
637 const AVOption *av_opt_next(const void *obj, const AVOption *prev);
638 
639 /**
640  * Iterate over AVOptions-enabled children of obj.
641  *
642  * @param prev result of a previous call to this function or NULL
643  * @return next AVOptions-enabled child or NULL
644  */
645 void *av_opt_child_next(void *obj, void *prev);
646 
647 /**
648  * Iterate over potential AVOptions-enabled children of parent.
649  *
650  * @param prev result of a previous call to this function or NULL
651  * @return AVClass corresponding to next potential child or NULL
652  */
653 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
654 
655 /**
656  * @defgroup opt_set_funcs Option setting functions
657  * @{
658  * Those functions set the field of obj with the given name to value.
659  *
660  * @param[in] obj A struct whose first element is a pointer to an AVClass.
661  * @param[in] name the name of the field to set
662  * @param[in] val The value to set. In case of av_opt_set() if the field is not
663  * of a string type, then the given string is parsed.
664  * SI postfixes and some named scalars are supported.
665  * If the field is of a numeric type, it has to be a numeric or named
666  * scalar. Behavior with more than one scalar and +- infix operators
667  * is undefined.
668  * If the field is of a flags type, it has to be a sequence of numeric
669  * scalars or named flags separated by '+' or '-'. Prefixing a flag
670  * with '+' causes it to be set without affecting the other flags;
671  * similarly, '-' unsets a flag.
672  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
673  * is passed here, then the option may be set on a child of obj.
674  *
675  * @return 0 if the value has been set, or an AVERROR code in case of
676  * error:
677  * AVERROR_OPTION_NOT_FOUND if no matching option exists
678  * AVERROR(ERANGE) if the value is out of range
679  * AVERROR(EINVAL) if the value is not valid
680  */
681 int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
682 int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
683 int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
684 int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
685 int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
686 int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
687 int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
688 int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
689 int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
690 int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
691 /**
692  * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
693  * caller still owns val is and responsible for freeing it.
694  */
695 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
696 
697 /**
698  * Set a binary option to an integer list.
699  *
700  * @param obj AVClass object to set options on
701  * @param name name of the binary option
702  * @param val pointer to an integer list (must have the correct type with
703  * regard to the contents of the list)
704  * @param term list terminator (usually 0 or -1)
705  * @param flags search flags
706  */
707 #define av_opt_set_int_list(obj, name, val, term, flags) \
708  (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
709  AVERROR(EINVAL) : \
710  av_opt_set_bin(obj, name, (const uint8_t *)(val), \
711  av_int_list_length(val, term) * sizeof(*(val)), flags))
712 
713 /**
714  * @}
715  */
716 
717 /**
718  * @defgroup opt_get_funcs Option getting functions
719  * @{
720  * Those functions get a value of the option with the given name from an object.
721  *
722  * @param[in] obj a struct whose first element is a pointer to an AVClass.
723  * @param[in] name name of the option to get.
724  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
725  * is passed here, then the option may be found in a child of obj.
726  * @param[out] out_val value of the option will be written here
727  * @return >=0 on success, a negative error code otherwise
728  */
729 /**
730  * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
731  *
732  * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the option has
733  * AV_OPT_TYPE_STRING or AV_OPT_TYPE_BINARY and is set to NULL, *out_val will be set
734  * to NULL instead of an allocated empty string.
735  */
736 int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
737 int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
738 int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
739 int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
740 int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
741 int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
742 int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
743 int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
744 int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
745 /**
746  * @param[out] out_val The returned dictionary is a copy of the actual value and must
747  * be freed with av_dict_free() by the caller
748  */
749 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
750 /**
751  * @}
752  */
753 /**
754  * Gets a pointer to the requested field in a struct.
755  * This function allows accessing a struct even when its fields are moved or
756  * renamed since the application making the access has been compiled,
757  *
758  * @returns a pointer to the field, it can be cast to the correct type and read
759  * or written to.
760  */
761 void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
762 
763 /**
764  * Free an AVOptionRanges struct and set it to NULL.
765  */
766 void av_opt_freep_ranges(AVOptionRanges **ranges);
767 
768 /**
769  * Get a list of allowed ranges for the given option.
770  *
771  * The returned list may depend on other fields in obj like for example profile.
772  *
773  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
774  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
775  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
776  *
777  * The result must be freed with av_opt_freep_ranges.
778  *
779  * @return number of compontents returned on success, a negative errro code otherwise
780  */
781 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
782 
783 /**
784  * Copy options from src object into dest object.
785  *
786  * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
787  * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
788  *
789  * @param dest Object to copy from
790  * @param src Object to copy into
791  * @return 0 on success, negative on error
792  */
793 int av_opt_copy(void *dest, const void *src);
794 
795 /**
796  * Get a default list of allowed ranges for the given option.
797  *
798  * This list is constructed without using the AVClass.query_ranges() callback
799  * and can be used as fallback from within the callback.
800  *
801  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
802  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
803  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
804  *
805  * The result must be freed with av_opt_free_ranges.
806  *
807  * @return number of compontents returned on success, a negative errro code otherwise
808  */
809 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
810 
811 /**
812  * Check if given option is set to its default value.
813  *
814  * Options o must belong to the obj. This function must not be called to check child's options state.
815  * @see av_opt_is_set_to_default_by_name().
816  *
817  * @param obj AVClass object to check option on
818  * @param o option to be checked
819  * @return >0 when option is set to its default,
820  * 0 when option is not set its default,
821  * <0 on error
822  */
823 int av_opt_is_set_to_default(void *obj, const AVOption *o);
824 
825 /**
826  * Check if given option is set to its default value.
827  *
828  * @param obj AVClass object to check option on
829  * @param name option name
830  * @param search_flags combination of AV_OPT_SEARCH_*
831  * @return >0 when option is set to its default,
832  * 0 when option is not set its default,
833  * <0 on error
834  */
835 int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
836 
837 
838 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
839 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
841 /**
842  * Serialize object's options.
843  *
844  * Create a string containing object's serialized options.
845  * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
846  * A key/value or pairs separator occurring in the serialized value or
847  * name string are escaped through the av_escape() function.
848  *
849  * @param[in] obj AVClass object to serialize
850  * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
851  * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
852  * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
853  * Buffer must be freed by the caller when is no longer needed.
854  * @param[in] key_val_sep character used to separate key from value
855  * @param[in] pairs_sep character used to separate two pairs from each other
856  * @return >= 0 on success, negative on error
857  * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
858  */
859 int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
860  const char key_val_sep, const char pairs_sep);
861 /**
862  * @}
863  */
864 
865 #endif /* AVUTIL_OPT_H */
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
Definition: opt.c:967
const char const char void * val
Definition: avisynth_c.h:634
A single allowed range of values, or a single allowed value.
Definition: opt.h:306
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
const char * s
Definition: avisynth_c.h:631
AVOption.
Definition: opt.h:245
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:544
AVFormatContext * ctx
Definition: movenc-test.c:48
const char * fmt
Definition: avisynth_c.h:632
void * av_opt_child_next(void *obj, void *prev)
Iterate over AVOptions-enabled children of obj.
Definition: opt.c:1611
double value_max
Definition: opt.h:313
const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
Definition: opt.c:1619
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1259
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:1379
external API header
int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int size, int search_flags)
Definition: opt.c:549
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:872
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.
Definition: opt.c:1944
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
Definition: opt.c:673
AVOptionType
Definition: opt.h:221
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:1932
AVRational q
Definition: opt.h:269
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:1836
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:906
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:1459
Public dictionary API.
const char * name
Definition: opt.h:246
uint8_t
AVOptionRange ** range
Array of option ranges.
Definition: opt.h:360
const char * help
short English help text
Definition: opt.h:252
const char * str
Definition: opt.h:267
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:539
double component_max
Definition: opt.h:318
ptrdiff_t size
Definition: opengl_enc.c:101
const OptionDef options[]
Definition: ffserver.c:3969
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:601
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
Definition: opt.c:940
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
Definition: opt.c:647
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:1626
static const uint16_t mask[17]
Definition: lzw.c:38
double max
maximum valid value for the option
Definition: opt.h:272
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:534
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.
Accept to parse a value without a key; the key will then be returned as NULL.
Definition: opt.h:529
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:1561
union AVOption::@219 default_val
the default value for scalar options
int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out)
int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt)
Definition: opt.c:945
const char * str
Definition: opt.h:307
const char * unit
The logical unit to which the option belongs.
Definition: opt.h:300
double component_min
Value's component range.
Definition: opt.h:318
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:657
double min
minimum valid value for the option
Definition: opt.h:271
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:1264
#define src
Definition: vp9dsp.c:530
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:1531
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:229
int flags
Definition: opt.h:274
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:1746
int is_range
Range flag.
Definition: opt.h:323
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
Definition: opt.c:848
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
Definition: opt.c:1817
int offset
The offset relative to the context structure where the option value is stored.
Definition: opt.h:258
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:1556
int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
Show the obj options.
Definition: opt.c:1247
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
Definition: opt.c:950
Describe the class of an AVClass context structure.
Definition: log.h:67
rational number numerator/denominator
Definition: rational.h:43
double dbl
Definition: opt.h:266
offset must point to AVRational
Definition: opt.h:235
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:232
static int flags
Definition: cpu.c:47
void av_opt_free(void *obj)
Free all allocated objects in obj.
Definition: opt.c:1511
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:1725
double value_min
Value range.
Definition: opt.h:313
rational numbers
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
Definition: opt.c:860
int av_opt_copy(void *dest, const void *src)
Copy options from src object into dest object.
Definition: opt.c:1668
int nb_ranges
Number of ranges per component.
Definition: opt.h:364
#define MKBETAG(a, b, c, d)
Definition: common.h:343
List of AVOptionRange structs.
Definition: opt.h:329
pixel format definitions
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:727
enum AVOptionType type
Definition: opt.h:259
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:1437
int64_t i64
Definition: opt.h:265
AVDictionary * opts
Definition: movenc-test.c:50
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:984
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:1567
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
Definition: opt.c:652
AVPixelFormat
Pixel format.
Definition: pixfmt.h:60
int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
Definition: opt.c:579
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:431
GLuint buffer
Definition: opengl_enc.c:102
const char * name
Definition: opengl_enc.c:103
int nb_components
Number of componentes.
Definition: opt.h:368
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
Definition: opt.c:888