FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
opt.h
Go to the documentation of this file.
1 /*
2  * AVOptions
3  * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVUTIL_OPT_H
23 #define AVUTIL_OPT_H
24 
25 /**
26  * @file
27  * AVOptions
28  */
29 
30 #include "rational.h"
31 #include "avutil.h"
32 #include "dict.h"
33 #include "log.h"
34 #include "pixfmt.h"
35 #include "samplefmt.h"
36 #include "version.h"
37 
38 /**
39  * @defgroup avoptions AVOptions
40  * @ingroup lavu_data
41  * @{
42  * AVOptions provide a generic system to declare options on arbitrary structs
43  * ("objects"). An option can have a help text, a type and a range of possible
44  * values. Options may then be enumerated, read and written to.
45  *
46  * @section avoptions_implement Implementing AVOptions
47  * This section describes how to add AVOptions capabilities to a struct.
48  *
49  * All AVOptions-related information is stored in an AVClass. Therefore
50  * the first member of the struct should be a pointer to an AVClass describing it.
51  * The option field of the AVClass must be set to a NULL-terminated static array
52  * of AVOptions. Each AVOption must have a non-empty name, a type, a default
53  * value and for number-type AVOptions also a range of allowed values. It must
54  * also declare an offset in bytes from the start of the struct, where the field
55  * associated with this AVOption is located. Other fields in the AVOption struct
56  * should also be set when applicable, but are not required.
57  *
58  * The following example illustrates an AVOptions-enabled struct:
59  * @code
60  * typedef struct test_struct {
61  * const AVClass *class;
62  * int int_opt;
63  * char *str_opt;
64  * uint8_t *bin_opt;
65  * int bin_len;
66  * } test_struct;
67  *
68  * static const AVOption test_options[] = {
69  * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
70  * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
71  * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
72  * AV_OPT_TYPE_STRING },
73  * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
74  * AV_OPT_TYPE_BINARY },
75  * { NULL },
76  * };
77  *
78  * static const AVClass test_class = {
79  * .class_name = "test class",
80  * .item_name = av_default_item_name,
81  * .option = test_options,
82  * .version = LIBAVUTIL_VERSION_INT,
83  * };
84  * @endcode
85  *
86  * Next, when allocating your struct, you must ensure that the AVClass pointer
87  * is set to the correct value. Then, av_opt_set_defaults() can be called to
88  * initialize defaults. After that the struct is ready to be used with the
89  * AVOptions API.
90  *
91  * When cleaning up, you may use the av_opt_free() function to automatically
92  * free all the allocated string and binary options.
93  *
94  * Continuing with the above example:
95  *
96  * @code
97  * test_struct *alloc_test_struct(void)
98  * {
99  * test_struct *ret = av_mallocz(sizeof(*ret));
100  * ret->class = &test_class;
101  * av_opt_set_defaults(ret);
102  * return ret;
103  * }
104  * void free_test_struct(test_struct **foo)
105  * {
106  * av_opt_free(*foo);
107  * av_freep(foo);
108  * }
109  * @endcode
110  *
111  * @subsection avoptions_implement_nesting Nesting
112  * It may happen that an AVOptions-enabled struct contains another
113  * AVOptions-enabled struct as a member (e.g. AVCodecContext in
114  * libavcodec exports generic options, while its priv_data field exports
115  * codec-specific options). In such a case, it is possible to set up the
116  * parent struct to export a child's options. To do that, simply
117  * implement AVClass.child_next() and AVClass.child_class_next() in the
118  * parent struct's AVClass.
119  * Assuming that the test_struct from above now also contains a
120  * child_struct field:
121  *
122  * @code
123  * typedef struct child_struct {
124  * AVClass *class;
125  * int flags_opt;
126  * } child_struct;
127  * static const AVOption child_opts[] = {
128  * { "test_flags", "This is a test option of flags type.",
129  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
130  * { NULL },
131  * };
132  * static const AVClass child_class = {
133  * .class_name = "child class",
134  * .item_name = av_default_item_name,
135  * .option = child_opts,
136  * .version = LIBAVUTIL_VERSION_INT,
137  * };
138  *
139  * void *child_next(void *obj, void *prev)
140  * {
141  * test_struct *t = obj;
142  * if (!prev && t->child_struct)
143  * return t->child_struct;
144  * return NULL
145  * }
146  * const AVClass child_class_next(const AVClass *prev)
147  * {
148  * return prev ? NULL : &child_class;
149  * }
150  * @endcode
151  * Putting child_next() and child_class_next() as defined above into
152  * test_class will now make child_struct's options accessible through
153  * test_struct (again, proper setup as described above needs to be done on
154  * child_struct right after it is created).
155  *
156  * From the above example it might not be clear why both child_next()
157  * and child_class_next() are needed. The distinction is that child_next()
158  * iterates over actually existing objects, while child_class_next()
159  * iterates over all possible child classes. E.g. if an AVCodecContext
160  * was initialized to use a codec which has private options, then its
161  * child_next() will return AVCodecContext.priv_data and finish
162  * iterating. OTOH child_class_next() on AVCodecContext.av_class will
163  * iterate over all available codecs with private options.
164  *
165  * @subsection avoptions_implement_named_constants Named constants
166  * It is possible to create named constants for options. Simply set the unit
167  * field of the option the constants should apply to a string and
168  * create the constants themselves as options of type AV_OPT_TYPE_CONST
169  * with their unit field set to the same string.
170  * Their default_val field should contain the value of the named
171  * constant.
172  * For example, to add some named constants for the test_flags option
173  * above, put the following into the child_opts array:
174  * @code
175  * { "test_flags", "This is a test option of flags type.",
176  * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
177  * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
178  * @endcode
179  *
180  * @section avoptions_use Using AVOptions
181  * This section deals with accessing options in an AVOptions-enabled struct.
182  * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
183  * AVFormatContext in libavformat.
184  *
185  * @subsection avoptions_use_examine Examining AVOptions
186  * The basic functions for examining options are av_opt_next(), which iterates
187  * over all options defined for one object, and av_opt_find(), which searches
188  * for an option with the given name.
189  *
190  * The situation is more complicated with nesting. An AVOptions-enabled struct
191  * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
192  * to av_opt_find() will make the function search children recursively.
193  *
194  * For enumerating there are basically two cases. The first is when you want to
195  * get all options that may potentially exist on the struct and its children
196  * (e.g. when constructing documentation). In that case you should call
197  * av_opt_child_class_next() recursively on the parent struct's AVClass. The
198  * second case is when you have an already initialized struct with all its
199  * children and you want to get all options that can be actually written or read
200  * from it. In that case you should call av_opt_child_next() recursively (and
201  * av_opt_next() on each result).
202  *
203  * @subsection avoptions_use_get_set Reading and writing AVOptions
204  * When setting options, you often have a string read directly from the
205  * user. In such a case, simply passing it to av_opt_set() is enough. For
206  * non-string type options, av_opt_set() will parse the string according to the
207  * option type.
208  *
209  * Similarly av_opt_get() will read any option type and convert it to a string
210  * which will be returned. Do not forget that the string is allocated, so you
211  * have to free it with av_free().
212  *
213  * In some cases it may be more convenient to put all options into an
214  * AVDictionary and call av_opt_set_dict() on it. A specific case of this
215  * are the format/codec open functions in lavf/lavc which take a dictionary
216  * filled with option as a parameter. This makes it possible to set some options
217  * that cannot be set otherwise, since e.g. the input file format is not known
218  * before the file is actually opened.
219  */
220 
229  AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
233  AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers
234  AV_OPT_TYPE_PIXEL_FMT = MKBETAG('P','F','M','T'),
235  AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'),
236  AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational
237  AV_OPT_TYPE_DURATION = MKBETAG('D','U','R',' '),
238  AV_OPT_TYPE_COLOR = MKBETAG('C','O','L','R'),
240  AV_OPT_TYPE_BOOL = MKBETAG('B','O','O','L'),
241 };
242 
243 /**
244  * AVOption
245  */
246 typedef struct AVOption {
247  const char *name;
248 
249  /**
250  * short English help text
251  * @todo What about other languages?
252  */
253  const char *help;
254 
255  /**
256  * The offset relative to the context structure where the option
257  * value is stored. It should be 0 for named constants.
258  */
259  int offset;
261 
262  /**
263  * the default value for scalar options
264  */
265  union {
266  int64_t i64;
267  double dbl;
268  const char *str;
269  /* TODO those are unused now */
271  } default_val;
272  double min; ///< minimum valid value for the option
273  double max; ///< maximum valid value for the option
274 
275  int flags;
276 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
277 #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
278 #if FF_API_OPT_TYPE_METADATA
279 #define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
280 #endif
281 #define AV_OPT_FLAG_AUDIO_PARAM 8
282 #define AV_OPT_FLAG_VIDEO_PARAM 16
283 #define AV_OPT_FLAG_SUBTITLE_PARAM 32
284 /**
285  * The option is intended for exporting values to the caller.
286  */
287 #define AV_OPT_FLAG_EXPORT 64
288 /**
289  * The option may not be set through the AVOptions API, only read.
290  * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
291  */
292 #define AV_OPT_FLAG_READONLY 128
293 #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
294 //FIXME think about enc-audio, ... style flags
295 
296  /**
297  * The logical unit to which the option belongs. Non-constant
298  * options and corresponding named constants share the same
299  * unit. May be NULL.
300  */
301  const char *unit;
302 } AVOption;
303 
304 /**
305  * A single allowed range of values, or a single allowed value.
306  */
307 typedef struct AVOptionRange {
308  const char *str;
309  /**
310  * Value range.
311  * For string ranges this represents the min/max length.
312  * For dimensions this represents the min/max pixel count or width/height in multi-component case.
313  */
315  /**
316  * Value's component range.
317  * For string this represents the unicode range for chars, 0-127 limits to ASCII.
318  */
320  /**
321  * Range flag.
322  * If set to 1 the struct encodes a range, if set to 0 a single value.
323  */
324  int is_range;
325 } AVOptionRange;
326 
327 /**
328  * List of AVOptionRange structs.
329  */
330 typedef struct AVOptionRanges {
331  /**
332  * Array of option ranges.
333  *
334  * Most of option types use just one component.
335  * Following describes multi-component option types:
336  *
337  * AV_OPT_TYPE_IMAGE_SIZE:
338  * component index 0: range of pixel count (width * height).
339  * component index 1: range of width.
340  * component index 2: range of height.
341  *
342  * @note To obtain multi-component version of this structure, user must
343  * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
344  * av_opt_query_ranges_default function.
345  *
346  * Multi-component range can be read as in following example:
347  *
348  * @code
349  * int range_index, component_index;
350  * AVOptionRanges *ranges;
351  * AVOptionRange *range[3]; //may require more than 3 in the future.
352  * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
353  * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
354  * for (component_index = 0; component_index < ranges->nb_components; component_index++)
355  * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
356  * //do something with range here.
357  * }
358  * av_opt_freep_ranges(&ranges);
359  * @endcode
360  */
362  /**
363  * Number of ranges per component.
364  */
366  /**
367  * Number of componentes.
368  */
371 
372 /**
373  * Show the obj options.
374  *
375  * @param req_flags requested flags for the options to show. Show only the
376  * options for which it is opt->flags & req_flags.
377  * @param rej_flags rejected flags for the options to show. Show only the
378  * options for which it is !(opt->flags & req_flags).
379  * @param av_log_obj log context to use for showing the options
380  */
381 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
382 
383 /**
384  * Set the values of all AVOption fields to their default values.
385  *
386  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
387  */
388 void av_opt_set_defaults(void *s);
389 
390 /**
391  * Set the values of all AVOption fields to their default values. Only these
392  * AVOption fields for which (opt->flags & mask) == flags will have their
393  * default applied to s.
394  *
395  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
396  * @param mask combination of AV_OPT_FLAG_*
397  * @param flags combination of AV_OPT_FLAG_*
398  */
399 void av_opt_set_defaults2(void *s, int mask, int flags);
400 
401 /**
402  * Parse the key/value pairs list in opts. For each key/value pair
403  * found, stores the value in the field in ctx that is named like the
404  * key. ctx must be an AVClass context, storing is done using
405  * AVOptions.
406  *
407  * @param opts options string to parse, may be NULL
408  * @param key_val_sep a 0-terminated list of characters used to
409  * separate key from value
410  * @param pairs_sep a 0-terminated list of characters used to separate
411  * two pairs from each other
412  * @return the number of successfully set key/value pairs, or a negative
413  * value corresponding to an AVERROR code in case of error:
414  * AVERROR(EINVAL) if opts cannot be parsed,
415  * the error code issued by av_opt_set() if a key/value pair
416  * cannot be set
417  */
418 int av_set_options_string(void *ctx, const char *opts,
419  const char *key_val_sep, const char *pairs_sep);
420 
421 /**
422  * Parse the key-value pairs list in opts. For each key=value pair found,
423  * set the value of the corresponding option in ctx.
424  *
425  * @param ctx the AVClass object to set options on
426  * @param opts the options string, key-value pairs separated by a
427  * delimiter
428  * @param shorthand a NULL-terminated array of options names for shorthand
429  * notation: if the first field in opts has no key part,
430  * the key is taken from the first element of shorthand;
431  * then again for the second, etc., until either opts is
432  * finished, shorthand is finished or a named option is
433  * found; after that, all options must be named
434  * @param key_val_sep a 0-terminated list of characters used to separate
435  * key from value, for example '='
436  * @param pairs_sep a 0-terminated list of characters used to separate
437  * two pairs from each other, for example ':' or ','
438  * @return the number of successfully set key=value pairs, or a negative
439  * value corresponding to an AVERROR code in case of error:
440  * AVERROR(EINVAL) if opts cannot be parsed,
441  * the error code issued by av_set_string3() if a key/value pair
442  * cannot be set
443  *
444  * Options names must use only the following characters: a-z A-Z 0-9 - . / _
445  * Separators must use characters distinct from option names and from each
446  * other.
447  */
448 int av_opt_set_from_string(void *ctx, const char *opts,
449  const char *const *shorthand,
450  const char *key_val_sep, const char *pairs_sep);
451 /**
452  * Free all allocated objects in obj.
453  */
454 void av_opt_free(void *obj);
455 
456 /**
457  * Check whether a particular flag is set in a flags field.
458  *
459  * @param field_name the name of the flag field option
460  * @param flag_name the name of the flag to check
461  * @return non-zero if the flag is set, zero if the flag isn't set,
462  * isn't of the right type, or the flags field doesn't exist.
463  */
464 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
465 
466 /**
467  * Set all the options from a given dictionary on an object.
468  *
469  * @param obj a struct whose first element is a pointer to AVClass
470  * @param options options to process. This dictionary will be freed and replaced
471  * by a new one containing all options not found in obj.
472  * Of course this new dictionary needs to be freed by caller
473  * with av_dict_free().
474  *
475  * @return 0 on success, a negative AVERROR if some option was found in obj,
476  * but could not be set.
477  *
478  * @see av_dict_copy()
479  */
480 int av_opt_set_dict(void *obj, struct AVDictionary **options);
481 
482 
483 /**
484  * Set all the options from a given dictionary on an object.
485  *
486  * @param obj a struct whose first element is a pointer to AVClass
487  * @param options options to process. This dictionary will be freed and replaced
488  * by a new one containing all options not found in obj.
489  * Of course this new dictionary needs to be freed by caller
490  * with av_dict_free().
491  * @param search_flags A combination of AV_OPT_SEARCH_*.
492  *
493  * @return 0 on success, a negative AVERROR if some option was found in obj,
494  * but could not be set.
495  *
496  * @see av_dict_copy()
497  */
498 int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
499 
500 /**
501  * Extract a key-value pair from the beginning of a string.
502  *
503  * @param ropts pointer to the options string, will be updated to
504  * point to the rest of the string (one of the pairs_sep
505  * or the final NUL)
506  * @param key_val_sep a 0-terminated list of characters used to separate
507  * key from value, for example '='
508  * @param pairs_sep a 0-terminated list of characters used to separate
509  * two pairs from each other, for example ':' or ','
510  * @param flags flags; see the AV_OPT_FLAG_* values below
511  * @param rkey parsed key; must be freed using av_free()
512  * @param rval parsed value; must be freed using av_free()
513  *
514  * @return >=0 for success, or a negative value corresponding to an
515  * AVERROR code in case of error; in particular:
516  * AVERROR(EINVAL) if no key is present
517  *
518  */
519 int av_opt_get_key_value(const char **ropts,
520  const char *key_val_sep, const char *pairs_sep,
521  unsigned flags,
522  char **rkey, char **rval);
523 
524 enum {
525 
526  /**
527  * Accept to parse a value without a key; the key will then be returned
528  * as NULL.
529  */
531 };
532 
533 /**
534  * @defgroup opt_eval_funcs Evaluating option strings
535  * @{
536  * This group of functions can be used to evaluate option strings
537  * and get numbers out of them. They do the same thing as av_opt_set(),
538  * except the result is written into the caller-supplied pointer.
539  *
540  * @param obj a struct whose first element is a pointer to AVClass.
541  * @param o an option for which the string is to be evaluated.
542  * @param val string to be evaluated.
543  * @param *_out value of the string will be written here.
544  *
545  * @return 0 on success, a negative number on failure.
546  */
547 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
548 int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
549 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
550 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
551 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
552 int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
553 /**
554  * @}
555  */
556 
557 #define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the
558  given object first. */
559 /**
560  * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
561  * instead of a required pointer to a struct containing AVClass. This is
562  * useful for searching for options without needing to allocate the corresponding
563  * object.
564  */
565 #define AV_OPT_SEARCH_FAKE_OBJ (1 << 1)
567 /**
568  * In av_opt_get, return NULL if the option has a pointer type and is set to NULL,
569  * rather than returning an empty string.
570  */
571 #define AV_OPT_ALLOW_NULL (1 << 2)
573 /**
574  * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
575  * one component for certain option types.
576  * @see AVOptionRanges for details.
577  */
578 #define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12)
580 /**
581  * Look for an option in an object. Consider only options which
582  * have all the specified flags set.
583  *
584  * @param[in] obj A pointer to a struct whose first element is a
585  * pointer to an AVClass.
586  * Alternatively a double pointer to an AVClass, if
587  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
588  * @param[in] name The name of the option to look for.
589  * @param[in] unit When searching for named constants, name of the unit
590  * it belongs to.
591  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
592  * @param search_flags A combination of AV_OPT_SEARCH_*.
593  *
594  * @return A pointer to the option found, or NULL if no option
595  * was found.
596  *
597  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
598  * directly with av_opt_set(). Use special calls which take an options
599  * AVDictionary (e.g. avformat_open_input()) to set options found with this
600  * flag.
601  */
602 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
603  int opt_flags, int search_flags);
604 
605 /**
606  * Look for an option in an object. Consider only options which
607  * have all the specified flags set.
608  *
609  * @param[in] obj A pointer to a struct whose first element is a
610  * pointer to an AVClass.
611  * Alternatively a double pointer to an AVClass, if
612  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
613  * @param[in] name The name of the option to look for.
614  * @param[in] unit When searching for named constants, name of the unit
615  * it belongs to.
616  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
617  * @param search_flags A combination of AV_OPT_SEARCH_*.
618  * @param[out] target_obj if non-NULL, an object to which the option belongs will be
619  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
620  * in search_flags. This parameter is ignored if search_flags contain
621  * AV_OPT_SEARCH_FAKE_OBJ.
622  *
623  * @return A pointer to the option found, or NULL if no option
624  * was found.
625  */
626 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
627  int opt_flags, int search_flags, void **target_obj);
628 
629 /**
630  * Iterate over all AVOptions belonging to obj.
631  *
632  * @param obj an AVOptions-enabled struct or a double pointer to an
633  * AVClass describing it.
634  * @param prev result of the previous call to av_opt_next() on this object
635  * or NULL
636  * @return next AVOption or NULL
637  */
638 const AVOption *av_opt_next(const void *obj, const AVOption *prev);
639 
640 /**
641  * Iterate over AVOptions-enabled children of obj.
642  *
643  * @param prev result of a previous call to this function or NULL
644  * @return next AVOptions-enabled child or NULL
645  */
646 void *av_opt_child_next(void *obj, void *prev);
647 
648 /**
649  * Iterate over potential AVOptions-enabled children of parent.
650  *
651  * @param prev result of a previous call to this function or NULL
652  * @return AVClass corresponding to next potential child or NULL
653  */
654 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
655 
656 /**
657  * @defgroup opt_set_funcs Option setting functions
658  * @{
659  * Those functions set the field of obj with the given name to value.
660  *
661  * @param[in] obj A struct whose first element is a pointer to an AVClass.
662  * @param[in] name the name of the field to set
663  * @param[in] val The value to set. In case of av_opt_set() if the field is not
664  * of a string type, then the given string is parsed.
665  * SI postfixes and some named scalars are supported.
666  * If the field is of a numeric type, it has to be a numeric or named
667  * scalar. Behavior with more than one scalar and +- infix operators
668  * is undefined.
669  * If the field is of a flags type, it has to be a sequence of numeric
670  * scalars or named flags separated by '+' or '-'. Prefixing a flag
671  * with '+' causes it to be set without affecting the other flags;
672  * similarly, '-' unsets a flag.
673  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
674  * is passed here, then the option may be set on a child of obj.
675  *
676  * @return 0 if the value has been set, or an AVERROR code in case of
677  * error:
678  * AVERROR_OPTION_NOT_FOUND if no matching option exists
679  * AVERROR(ERANGE) if the value is out of range
680  * AVERROR(EINVAL) if the value is not valid
681  */
682 int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
683 int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
684 int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
685 int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
686 int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
687 int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
688 int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
689 int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
690 int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
691 int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
692 /**
693  * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
694  * caller still owns val is and responsible for freeing it.
695  */
696 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
697 
698 /**
699  * Set a binary option to an integer list.
700  *
701  * @param obj AVClass object to set options on
702  * @param name name of the binary option
703  * @param val pointer to an integer list (must have the correct type with
704  * regard to the contents of the list)
705  * @param term list terminator (usually 0 or -1)
706  * @param flags search flags
707  */
708 #define av_opt_set_int_list(obj, name, val, term, flags) \
709  (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
710  AVERROR(EINVAL) : \
711  av_opt_set_bin(obj, name, (const uint8_t *)(val), \
712  av_int_list_length(val, term) * sizeof(*(val)), flags))
713 
714 /**
715  * @}
716  */
717 
718 /**
719  * @defgroup opt_get_funcs Option getting functions
720  * @{
721  * Those functions get a value of the option with the given name from an object.
722  *
723  * @param[in] obj a struct whose first element is a pointer to an AVClass.
724  * @param[in] name name of the option to get.
725  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
726  * is passed here, then the option may be found in a child of obj.
727  * @param[out] out_val value of the option will be written here
728  * @return >=0 on success, a negative error code otherwise
729  */
730 /**
731  * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
732  *
733  * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the option has
734  * AV_OPT_TYPE_STRING or AV_OPT_TYPE_BINARY and is set to NULL, *out_val will be set
735  * to NULL instead of an allocated empty string.
736  */
737 int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
738 int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
739 int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
740 int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
741 int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
742 int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
743 int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
744 int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
745 int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
746 /**
747  * @param[out] out_val The returned dictionary is a copy of the actual value and must
748  * be freed with av_dict_free() by the caller
749  */
750 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
751 /**
752  * @}
753  */
754 /**
755  * Gets a pointer to the requested field in a struct.
756  * This function allows accessing a struct even when its fields are moved or
757  * renamed since the application making the access has been compiled,
758  *
759  * @returns a pointer to the field, it can be cast to the correct type and read
760  * or written to.
761  */
762 void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
763 
764 /**
765  * Free an AVOptionRanges struct and set it to NULL.
766  */
767 void av_opt_freep_ranges(AVOptionRanges **ranges);
768 
769 /**
770  * Get a list of allowed ranges for the given option.
771  *
772  * The returned list may depend on other fields in obj like for example profile.
773  *
774  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
775  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
776  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
777  *
778  * The result must be freed with av_opt_freep_ranges.
779  *
780  * @return number of compontents returned on success, a negative errro code otherwise
781  */
782 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
783 
784 /**
785  * Copy options from src object into dest object.
786  *
787  * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
788  * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
789  *
790  * @param dest Object to copy from
791  * @param src Object to copy into
792  * @return 0 on success, negative on error
793  */
794 int av_opt_copy(void *dest, const void *src);
795 
796 /**
797  * Get a default list of allowed ranges for the given option.
798  *
799  * This list is constructed without using the AVClass.query_ranges() callback
800  * and can be used as fallback from within the callback.
801  *
802  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
803  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
804  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
805  *
806  * The result must be freed with av_opt_free_ranges.
807  *
808  * @return number of compontents returned on success, a negative errro code otherwise
809  */
810 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
811 
812 /**
813  * Check if given option is set to its default value.
814  *
815  * Options o must belong to the obj. This function must not be called to check child's options state.
816  * @see av_opt_is_set_to_default_by_name().
817  *
818  * @param obj AVClass object to check option on
819  * @param o option to be checked
820  * @return >0 when option is set to its default,
821  * 0 when option is not set its default,
822  * <0 on error
823  */
824 int av_opt_is_set_to_default(void *obj, const AVOption *o);
825 
826 /**
827  * Check if given option is set to its default value.
828  *
829  * @param obj AVClass object to check option on
830  * @param name option name
831  * @param search_flags combination of AV_OPT_SEARCH_*
832  * @return >0 when option is set to its default,
833  * 0 when option is not set its default,
834  * <0 on error
835  */
836 int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
837 
838 
839 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
840 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
842 /**
843  * Serialize object's options.
844  *
845  * Create a string containing object's serialized options.
846  * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
847  * A key/value or pairs separator occurring in the serialized value or
848  * name string are escaped through the av_escape() function.
849  *
850  * @param[in] obj AVClass object to serialize
851  * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
852  * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
853  * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
854  * Buffer must be freed by the caller when is no longer needed.
855  * @param[in] key_val_sep character used to separate key from value
856  * @param[in] pairs_sep character used to separate two pairs from each other
857  * @return >= 0 on success, negative on error
858  * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
859  */
860 int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
861  const char key_val_sep, const char pairs_sep);
862 /**
863  * @}
864  */
865 
866 #endif /* AVUTIL_OPT_H */
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
Definition: opt.c:996
const char const char void * val
Definition: avisynth_c.h:771
A single allowed range of values, or a single allowed value.
Definition: opt.h:307
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
const char * s
Definition: avisynth_c.h:768
AVOption.
Definition: opt.h:246
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:570
const char * fmt
Definition: avisynth_c.h:769
void * av_opt_child_next(void *obj, void *prev)
Iterate over AVOptions-enabled children of obj.
Definition: opt.c:1646
double value_max
Definition: opt.h:314
const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
Definition: opt.c:1654
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1293
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:1414
Convenience header that includes libavutil's core.
int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int size, int search_flags)
Definition: opt.c:575
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:901
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:1982
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
Definition: opt.c:699
#define src
Definition: vp8dsp.c:254
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:1970
AVRational q
Definition: opt.h:270
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:1873
union AVOption::@240 default_val
the default value for scalar options
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:935
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:1494
Public dictionary API.
const char * name
Definition: opt.h:247
uint8_t
AVOptionRange ** range
Array of option ranges.
Definition: opt.h:361
const char * help
short English help text
Definition: opt.h:253
const char * str
Definition: opt.h:268
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:565
static int flags
Definition: log.c:57
double component_max
Definition: opt.h:319
ptrdiff_t size
Definition: opengl_enc.c:101
const OptionDef options[]
Definition: ffserver.c:3947
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:627
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
Definition: opt.c:969
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
Definition: opt.c:673
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:1661
static const uint16_t mask[17]
Definition: lzw.c:38
double max
maximum valid value for the option
Definition: opt.h:273
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:560
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:1596
int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out)
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:974
const char * str
Definition: opt.h:308
AVFormatContext * ctx
Definition: movenc.c:48
const char * unit
The logical unit to which the option belongs.
Definition: opt.h:301
double component_min
Value's component range.
Definition: opt.h:319
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:683
double min
minimum valid value for the option
Definition: opt.h:272
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:1298
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:1566
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:229
int flags
Definition: opt.h:275
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:1782
int is_range
Range flag.
Definition: opt.h:324
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
Definition: opt.c:877
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
Definition: opt.c:1854
int offset
The offset relative to the context structure where the option value is stored.
Definition: opt.h:259
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:1591
int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
Show the obj options.
Definition: opt.c:1281
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
Definition: opt.c:979
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
double dbl
Definition: opt.h:267
offset must point to AVRational
Definition: opt.h:236
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:233
void av_opt_free(void *obj)
Free all allocated objects in obj.
Definition: opt.c:1546
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:1761
double value_min
Value range.
Definition: opt.h:314
Utilties for rational number calculation.
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
Definition: opt.c:889
int av_opt_copy(void *dest, const void *src)
Copy options from src object into dest object.
Definition: opt.c:1704
int nb_ranges
Number of ranges per component.
Definition: opt.h:365
#define MKBETAG(a, b, c, d)
Definition: common.h:343
List of AVOptionRange structs.
Definition: opt.h:330
pixel format definitions
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:753
enum AVOptionType type
Definition: opt.h:260
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:1472
int64_t i64
Definition: opt.h:266
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:1013
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:1602
Accept to parse a value without a key; the key will then be returned as NULL.
Definition: opt.h:530
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
Definition: opt.c:678
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:605
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:451
GLuint buffer
Definition: opengl_enc.c:102
const char * name
Definition: opengl_enc.c:103
int nb_components
Number of componentes.
Definition: opt.h:369
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
Definition: opt.c:917