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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 #if FF_API_OLD_AVOPTIONS
247  FF_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
249 #endif
250 };
251 
252 /**
253  * AVOption
254  */
255 typedef struct AVOption {
256  const char *name;
257 
258  /**
259  * short English help text
260  * @todo What about other languages?
261  */
262  const char *help;
263 
264  /**
265  * The offset relative to the context structure where the option
266  * value is stored. It should be 0 for named constants.
267  */
268  int offset;
270 
271  /**
272  * the default value for scalar options
273  */
274  union {
275  int64_t i64;
276  double dbl;
277  const char *str;
278  /* TODO those are unused now */
280  } default_val;
281  double min; ///< minimum valid value for the option
282  double max; ///< maximum valid value for the option
283 
284  int flags;
285 #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
286 #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
287 #if FF_API_OPT_TYPE_METADATA
288 #define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
289 #endif
290 #define AV_OPT_FLAG_AUDIO_PARAM 8
291 #define AV_OPT_FLAG_VIDEO_PARAM 16
292 #define AV_OPT_FLAG_SUBTITLE_PARAM 32
293 /**
294  * The option is inteded for exporting values to the caller.
295  */
296 #define AV_OPT_FLAG_EXPORT 64
297 /**
298  * The option may not be set through the AVOptions API, only read.
299  * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
300  */
301 #define AV_OPT_FLAG_READONLY 128
302 #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
303 //FIXME think about enc-audio, ... style flags
304 
305  /**
306  * The logical unit to which the option belongs. Non-constant
307  * options and corresponding named constants share the same
308  * unit. May be NULL.
309  */
310  const char *unit;
311 } AVOption;
312 
313 /**
314  * A single allowed range of values, or a single allowed value.
315  */
316 typedef struct AVOptionRange {
317  const char *str;
318  /**
319  * Value range.
320  * For string ranges this represents the min/max length.
321  * For dimensions this represents the min/max pixel count or width/height in multi-component case.
322  */
324  /**
325  * Value's component range.
326  * For string this represents the unicode range for chars, 0-127 limits to ASCII.
327  */
329  /**
330  * Range flag.
331  * If set to 1 the struct encodes a range, if set to 0 a single value.
332  */
333  int is_range;
334 } AVOptionRange;
335 
336 /**
337  * List of AVOptionRange structs.
338  */
339 typedef struct AVOptionRanges {
340  /**
341  * Array of option ranges.
342  *
343  * Most of option types use just one component.
344  * Following describes multi-component option types:
345  *
346  * AV_OPT_TYPE_IMAGE_SIZE:
347  * component index 0: range of pixel count (width * height).
348  * component index 1: range of width.
349  * component index 2: range of height.
350  *
351  * @note To obtain multi-component version of this structure, user must
352  * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or
353  * av_opt_query_ranges_default function.
354  *
355  * Multi-component range can be read as in following example:
356  *
357  * @code
358  * int range_index, component_index;
359  * AVOptionRanges *ranges;
360  * AVOptionRange *range[3]; //may require more than 3 in the future.
361  * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE);
362  * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) {
363  * for (component_index = 0; component_index < ranges->nb_components; component_index++)
364  * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index];
365  * //do something with range here.
366  * }
367  * av_opt_freep_ranges(&ranges);
368  * @endcode
369  */
371  /**
372  * Number of ranges per component.
373  */
375  /**
376  * Number of componentes.
377  */
380 
381 
382 #if FF_API_OLD_AVOPTIONS
383 /**
384  * Set the field of obj with the given name to value.
385  *
386  * @param[in] obj A struct whose first element is a pointer to an
387  * AVClass.
388  * @param[in] name the name of the field to set
389  * @param[in] val The value to set. If the field is not of a string
390  * type, then the given string is parsed.
391  * SI postfixes and some named scalars are supported.
392  * If the field is of a numeric type, it has to be a numeric or named
393  * scalar. Behavior with more than one scalar and +- infix operators
394  * is undefined.
395  * If the field is of a flags type, it has to be a sequence of numeric
396  * scalars or named flags separated by '+' or '-'. Prefixing a flag
397  * with '+' causes it to be set without affecting the other flags;
398  * similarly, '-' unsets a flag.
399  * @param[out] o_out if non-NULL put here a pointer to the AVOption
400  * found
401  * @param alloc this parameter is currently ignored
402  * @return 0 if the value has been set, or an AVERROR code in case of
403  * error:
404  * AVERROR_OPTION_NOT_FOUND if no matching option exists
405  * AVERROR(ERANGE) if the value is out of range
406  * AVERROR(EINVAL) if the value is not valid
407  * @deprecated use av_opt_set()
408  */
410 int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
411 
412 attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n);
413 attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n);
414 attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n);
415 
417 double av_get_double(void *obj, const char *name, const AVOption **o_out);
419 AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
421 int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
422 attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
424 #endif
425 
426 /**
427  * Show the obj options.
428  *
429  * @param req_flags requested flags for the options to show. Show only the
430  * options for which it is opt->flags & req_flags.
431  * @param rej_flags rejected flags for the options to show. Show only the
432  * options for which it is !(opt->flags & req_flags).
433  * @param av_log_obj log context to use for showing the options
434  */
435 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
436 
437 /**
438  * Set the values of all AVOption fields to their default values.
439  *
440  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
441  */
442 void av_opt_set_defaults(void *s);
443 
444 /**
445  * Set the values of all AVOption fields to their default values. Only these
446  * AVOption fields for which (opt->flags & mask) == flags will have their
447  * default applied to s.
448  *
449  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
450  * @param mask combination of AV_OPT_FLAG_*
451  * @param flags combination of AV_OPT_FLAG_*
452  */
453 void av_opt_set_defaults2(void *s, int mask, int flags);
454 
455 /**
456  * Parse the key/value pairs list in opts. For each key/value pair
457  * found, stores the value in the field in ctx that is named like the
458  * key. ctx must be an AVClass context, storing is done using
459  * AVOptions.
460  *
461  * @param opts options string to parse, may be NULL
462  * @param key_val_sep a 0-terminated list of characters used to
463  * separate key from value
464  * @param pairs_sep a 0-terminated list of characters used to separate
465  * two pairs from each other
466  * @return the number of successfully set key/value pairs, or a negative
467  * value corresponding to an AVERROR code in case of error:
468  * AVERROR(EINVAL) if opts cannot be parsed,
469  * the error code issued by av_opt_set() if a key/value pair
470  * cannot be set
471  */
472 int av_set_options_string(void *ctx, const char *opts,
473  const char *key_val_sep, const char *pairs_sep);
474 
475 /**
476  * Parse the key-value pairs list in opts. For each key=value pair found,
477  * set the value of the corresponding option in ctx.
478  *
479  * @param ctx the AVClass object to set options on
480  * @param opts the options string, key-value pairs separated by a
481  * delimiter
482  * @param shorthand a NULL-terminated array of options names for shorthand
483  * notation: if the first field in opts has no key part,
484  * the key is taken from the first element of shorthand;
485  * then again for the second, etc., until either opts is
486  * finished, shorthand is finished or a named option is
487  * found; after that, all options must be named
488  * @param key_val_sep a 0-terminated list of characters used to separate
489  * key from value, for example '='
490  * @param pairs_sep a 0-terminated list of characters used to separate
491  * two pairs from each other, for example ':' or ','
492  * @return the number of successfully set key=value pairs, or a negative
493  * value corresponding to an AVERROR code in case of error:
494  * AVERROR(EINVAL) if opts cannot be parsed,
495  * the error code issued by av_set_string3() if a key/value pair
496  * cannot be set
497  *
498  * Options names must use only the following characters: a-z A-Z 0-9 - . / _
499  * Separators must use characters distinct from option names and from each
500  * other.
501  */
502 int av_opt_set_from_string(void *ctx, const char *opts,
503  const char *const *shorthand,
504  const char *key_val_sep, const char *pairs_sep);
505 /**
506  * Free all allocated objects in obj.
507  */
508 void av_opt_free(void *obj);
509 
510 /**
511  * Check whether a particular flag is set in a flags field.
512  *
513  * @param field_name the name of the flag field option
514  * @param flag_name the name of the flag to check
515  * @return non-zero if the flag is set, zero if the flag isn't set,
516  * isn't of the right type, or the flags field doesn't exist.
517  */
518 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
519 
520 /**
521  * Set all the options from a given dictionary on an object.
522  *
523  * @param obj a struct whose first element is a pointer to AVClass
524  * @param options options to process. This dictionary will be freed and replaced
525  * by a new one containing all options not found in obj.
526  * Of course this new dictionary needs to be freed by caller
527  * with av_dict_free().
528  *
529  * @return 0 on success, a negative AVERROR if some option was found in obj,
530  * but could not be set.
531  *
532  * @see av_dict_copy()
533  */
534 int av_opt_set_dict(void *obj, struct AVDictionary **options);
535 
536 
537 /**
538  * Set all the options from a given dictionary on an object.
539  *
540  * @param obj a struct whose first element is a pointer to AVClass
541  * @param options options to process. This dictionary will be freed and replaced
542  * by a new one containing all options not found in obj.
543  * Of course this new dictionary needs to be freed by caller
544  * with av_dict_free().
545  * @param search_flags A combination of AV_OPT_SEARCH_*.
546  *
547  * @return 0 on success, a negative AVERROR if some option was found in obj,
548  * but could not be set.
549  *
550  * @see av_dict_copy()
551  */
552 int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags);
553 
554 /**
555  * Extract a key-value pair from the beginning of a string.
556  *
557  * @param ropts pointer to the options string, will be updated to
558  * point to the rest of the string (one of the pairs_sep
559  * or the final NUL)
560  * @param key_val_sep a 0-terminated list of characters used to separate
561  * key from value, for example '='
562  * @param pairs_sep a 0-terminated list of characters used to separate
563  * two pairs from each other, for example ':' or ','
564  * @param flags flags; see the AV_OPT_FLAG_* values below
565  * @param rkey parsed key; must be freed using av_free()
566  * @param rval parsed value; must be freed using av_free()
567  *
568  * @return >=0 for success, or a negative value corresponding to an
569  * AVERROR code in case of error; in particular:
570  * AVERROR(EINVAL) if no key is present
571  *
572  */
573 int av_opt_get_key_value(const char **ropts,
574  const char *key_val_sep, const char *pairs_sep,
575  unsigned flags,
576  char **rkey, char **rval);
577 
578 enum {
579 
580  /**
581  * Accept to parse a value without a key; the key will then be returned
582  * as NULL.
583  */
585 };
586 
587 /**
588  * @defgroup opt_eval_funcs Evaluating option strings
589  * @{
590  * This group of functions can be used to evaluate option strings
591  * and get numbers out of them. They do the same thing as av_opt_set(),
592  * except the result is written into the caller-supplied pointer.
593  *
594  * @param obj a struct whose first element is a pointer to AVClass.
595  * @param o an option for which the string is to be evaluated.
596  * @param val string to be evaluated.
597  * @param *_out value of the string will be written here.
598  *
599  * @return 0 on success, a negative number on failure.
600  */
601 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out);
602 int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out);
603 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out);
604 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out);
605 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out);
606 int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out);
607 /**
608  * @}
609  */
610 
611 #define AV_OPT_SEARCH_CHILDREN 0x0001 /**< Search in possible children of the
612  given object first. */
613 /**
614  * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
615  * instead of a required pointer to a struct containing AVClass. This is
616  * useful for searching for options without needing to allocate the corresponding
617  * object.
618  */
619 #define AV_OPT_SEARCH_FAKE_OBJ 0x0002
621 /**
622  * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than
623  * one component for certain option types.
624  * @see AVOptionRanges for details.
625  */
626 #define AV_OPT_MULTI_COMPONENT_RANGE 0x1000
628 /**
629  * Look for an option in an object. Consider only options which
630  * have all the specified flags set.
631  *
632  * @param[in] obj A pointer to a struct whose first element is a
633  * pointer to an AVClass.
634  * Alternatively a double pointer to an AVClass, if
635  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
636  * @param[in] name The name of the option to look for.
637  * @param[in] unit When searching for named constants, name of the unit
638  * it belongs to.
639  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
640  * @param search_flags A combination of AV_OPT_SEARCH_*.
641  *
642  * @return A pointer to the option found, or NULL if no option
643  * was found.
644  *
645  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
646  * directly with av_opt_set(). Use special calls which take an options
647  * AVDictionary (e.g. avformat_open_input()) to set options found with this
648  * flag.
649  */
650 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
651  int opt_flags, int search_flags);
652 
653 /**
654  * Look for an option in an object. Consider only options which
655  * have all the specified flags set.
656  *
657  * @param[in] obj A pointer to a struct whose first element is a
658  * pointer to an AVClass.
659  * Alternatively a double pointer to an AVClass, if
660  * AV_OPT_SEARCH_FAKE_OBJ search flag is set.
661  * @param[in] name The name of the option to look for.
662  * @param[in] unit When searching for named constants, name of the unit
663  * it belongs to.
664  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
665  * @param search_flags A combination of AV_OPT_SEARCH_*.
666  * @param[out] target_obj if non-NULL, an object to which the option belongs will be
667  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
668  * in search_flags. This parameter is ignored if search_flags contain
669  * AV_OPT_SEARCH_FAKE_OBJ.
670  *
671  * @return A pointer to the option found, or NULL if no option
672  * was found.
673  */
674 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
675  int opt_flags, int search_flags, void **target_obj);
676 
677 /**
678  * Iterate over all AVOptions belonging to obj.
679  *
680  * @param obj an AVOptions-enabled struct or a double pointer to an
681  * AVClass describing it.
682  * @param prev result of the previous call to av_opt_next() on this object
683  * or NULL
684  * @return next AVOption or NULL
685  */
686 const AVOption *av_opt_next(FF_CONST_AVUTIL55 void *obj, const AVOption *prev);
687 
688 /**
689  * Iterate over AVOptions-enabled children of obj.
690  *
691  * @param prev result of a previous call to this function or NULL
692  * @return next AVOptions-enabled child or NULL
693  */
694 void *av_opt_child_next(void *obj, void *prev);
695 
696 /**
697  * Iterate over potential AVOptions-enabled children of parent.
698  *
699  * @param prev result of a previous call to this function or NULL
700  * @return AVClass corresponding to next potential child or NULL
701  */
702 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
703 
704 /**
705  * @defgroup opt_set_funcs Option setting functions
706  * @{
707  * Those functions set the field of obj with the given name to value.
708  *
709  * @param[in] obj A struct whose first element is a pointer to an AVClass.
710  * @param[in] name the name of the field to set
711  * @param[in] val The value to set. In case of av_opt_set() if the field is not
712  * of a string type, then the given string is parsed.
713  * SI postfixes and some named scalars are supported.
714  * If the field is of a numeric type, it has to be a numeric or named
715  * scalar. Behavior with more than one scalar and +- infix operators
716  * is undefined.
717  * If the field is of a flags type, it has to be a sequence of numeric
718  * scalars or named flags separated by '+' or '-'. Prefixing a flag
719  * with '+' causes it to be set without affecting the other flags;
720  * similarly, '-' unsets a flag.
721  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
722  * is passed here, then the option may be set on a child of obj.
723  *
724  * @return 0 if the value has been set, or an AVERROR code in case of
725  * error:
726  * AVERROR_OPTION_NOT_FOUND if no matching option exists
727  * AVERROR(ERANGE) if the value is out of range
728  * AVERROR(EINVAL) if the value is not valid
729  */
730 int av_opt_set (void *obj, const char *name, const char *val, int search_flags);
731 int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags);
732 int av_opt_set_double (void *obj, const char *name, double val, int search_flags);
733 int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags);
734 int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
735 int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
736 int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
737 int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
738 int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
739 int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
740 /**
741  * @note Any old dictionary present is discarded and replaced with a copy of the new one. The
742  * caller still owns val is and responsible for freeing it.
743  */
744 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags);
745 
746 /**
747  * Set a binary option to an integer list.
748  *
749  * @param obj AVClass object to set options on
750  * @param name name of the binary option
751  * @param val pointer to an integer list (must have the correct type with
752  * regard to the contents of the list)
753  * @param term list terminator (usually 0 or -1)
754  * @param flags search flags
755  */
756 #define av_opt_set_int_list(obj, name, val, term, flags) \
757  (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
758  AVERROR(EINVAL) : \
759  av_opt_set_bin(obj, name, (const uint8_t *)(val), \
760  av_int_list_length(val, term) * sizeof(*(val)), flags))
761 
762 /**
763  * @}
764  */
765 
766 /**
767  * @defgroup opt_get_funcs Option getting functions
768  * @{
769  * Those functions get a value of the option with the given name from an object.
770  *
771  * @param[in] obj a struct whose first element is a pointer to an AVClass.
772  * @param[in] name name of the option to get.
773  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
774  * is passed here, then the option may be found in a child of obj.
775  * @param[out] out_val value of the option will be written here
776  * @return >=0 on success, a negative error code otherwise
777  */
778 /**
779  * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
780  */
781 int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val);
782 int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val);
783 int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val);
784 int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val);
785 int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
786 int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
787 int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
788 int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
789 int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
790 /**
791  * @param[out] out_val The returned dictionary is a copy of the actual value and must
792  * be freed with av_dict_free() by the caller
793  */
794 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val);
795 /**
796  * @}
797  */
798 /**
799  * Gets a pointer to the requested field in a struct.
800  * This function allows accessing a struct even when its fields are moved or
801  * renamed since the application making the access has been compiled,
802  *
803  * @returns a pointer to the field, it can be cast to the correct type and read
804  * or written to.
805  */
806 void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
807 
808 /**
809  * Free an AVOptionRanges struct and set it to NULL.
810  */
811 void av_opt_freep_ranges(AVOptionRanges **ranges);
812 
813 /**
814  * Get a list of allowed ranges for the given option.
815  *
816  * The returned list may depend on other fields in obj like for example profile.
817  *
818  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
819  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
820  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
821  *
822  * The result must be freed with av_opt_freep_ranges.
823  *
824  * @return number of compontents returned on success, a negative errro code otherwise
825  */
826 int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
827 
828 /**
829  * Copy options from src object into dest object.
830  *
831  * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object.
832  * Original memory allocated for such options is freed unless both src and dest options points to the same memory.
833  *
834  * @param dest Object to copy from
835  * @param src Object to copy into
836  * @return 0 on success, negative on error
837  */
838 int av_opt_copy(void *dest, FF_CONST_AVUTIL55 void *src);
839 
840 /**
841  * Get a default list of allowed ranges for the given option.
842  *
843  * This list is constructed without using the AVClass.query_ranges() callback
844  * and can be used as fallback from within the callback.
845  *
846  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
847  * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
848  * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges
849  *
850  * The result must be freed with av_opt_free_ranges.
851  *
852  * @return number of compontents returned on success, a negative errro code otherwise
853  */
854 int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
855 
856 /**
857  * Check if given option is set to its default value.
858  *
859  * Options o must belong to the obj. This function must not be called to check child's options state.
860  * @see av_opt_is_set_to_default_by_name().
861  *
862  * @param obj AVClass object to check option on
863  * @param o option to be checked
864  * @return >0 when option is set to its default,
865  * 0 when option is not set its default,
866  * <0 on error
867  */
868 int av_opt_is_set_to_default(void *obj, const AVOption *o);
869 
870 /**
871  * Check if given option is set to its default value.
872  *
873  * @param obj AVClass object to check option on
874  * @param name option name
875  * @param search_flags combination of AV_OPT_SEARCH_*
876  * @return >0 when option is set to its default,
877  * 0 when option is not set its default,
878  * <0 on error
879  */
880 int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags);
881 
882 
883 #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only.
884 #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only.
886 /**
887  * Serialize object's options.
888  *
889  * Create a string containing object's serialized options.
890  * Such string may be passed back to av_opt_set_from_string() in order to restore option values.
891  * A key/value or pairs separator occurring in the serialized value or
892  * name string are escaped through the av_escape() function.
893  *
894  * @param[in] obj AVClass object to serialize
895  * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG)
896  * @param[in] flags combination of AV_OPT_SERIALIZE_* flags
897  * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options.
898  * Buffer must be freed by the caller when is no longer needed.
899  * @param[in] key_val_sep character used to separate key from value
900  * @param[in] pairs_sep character used to separate two pairs from each other
901  * @return >= 0 on success, negative on error
902  * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
903  */
904 int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer,
905  const char key_val_sep, const char pairs_sep);
906 /**
907  * @}
908  */
909 
910 #endif /* AVUTIL_OPT_H */
int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
Definition: opt.c:942
const char const char void * val
Definition: avisynth_c.h:634
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:247
A single allowed range of values, or a single allowed value.
Definition: opt.h:316
int av_opt_eval_float(void *obj, const AVOption *o, const char *val, float *float_out)
const char * s
Definition: avisynth_c.h:631
attribute_deprecated const AVOption * av_set_int(void *obj, const char *name, int64_t n)
Definition: opt.c:482
AVOption.
Definition: opt.h:255
int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:501
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:1531
double value_max
Definition: opt.h:323
const AVClass * av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
Iterate over potential AVOptions-enabled children of parent.
Definition: opt.c:1539
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1178
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:1300
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:506
int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:847
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:1846
int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags)
Definition: opt.c:671
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:1834
attribute_deprecated const char * av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len)
Definition: opt.c:636
AVRational q
Definition: opt.h:279
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:1739
int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val)
Definition: opt.c:881
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:1380
Public dictionary API.
const char * name
Definition: opt.h:256
uint8_t
AVOptionRange ** range
Array of option ranges.
Definition: opt.h:370
Accept to parse a value without a key; the key will then be returned as NULL.
Definition: opt.h:584
const char * help
short English help text
Definition: opt.h:262
attribute_deprecated const AVOption * av_set_double(void *obj, const char *name, double n)
Definition: opt.c:466
const char * str
Definition: opt.h:277
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:496
attribute_deprecated AVRational av_get_q(void *obj, const char *name, const AVOption **o_out)
Definition: opt.c:797
double component_max
Definition: opt.h:328
ptrdiff_t size
Definition: opengl_enc.c:101
const OptionDef options[]
Definition: ffserver.c:3807
int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags)
Definition: opt.c:558
int av_opt_get_pixel_fmt(void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt)
Definition: opt.c:915
int av_opt_set_pixel_fmt(void *obj, const char *name, enum AVPixelFormat fmt, int search_flags)
Definition: opt.c:604
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:1546
static const uint16_t mask[17]
Definition: lzw.c:38
double max
maximum valid value for the option
Definition: opt.h:282
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:491
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:1481
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:920
const AVOption * av_opt_next(FF_CONST_AVUTIL55 void *obj, const AVOption *prev)
Iterate over all AVOptions belonging to obj.
Definition: opt.c:51
const char * str
Definition: opt.h:317
int av_opt_copy(void *dest, FF_CONST_AVUTIL55 void *src)
Copy options from src object into dest object.
Definition: opt.c:1576
const char * unit
The logical unit to which the option belongs.
Definition: opt.h:310
double component_min
Value's component range.
Definition: opt.h:328
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:614
double min
minimum valid value for the option
Definition: opt.h:281
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:1183
int n
Definition: avisynth_c.h:547
attribute_deprecated double av_get_double(void *obj, const char *name, const AVOption **o_out)
Definition: opt.c:786
attribute_deprecated const AVOption * av_set_q(void *obj, const char *name, AVRational n)
Definition: opt.c:474
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:1452
offset must point to a pointer immediately followed by an int for the length
Definition: opt.h:229
int flags
Definition: opt.h:284
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:1650
int is_range
Range flag.
Definition: opt.h:333
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
Definition: opt.c:823
void av_opt_freep_ranges(AVOptionRanges **ranges)
Free an AVOptionRanges struct and set it to NULL.
Definition: opt.c:1720
AVS_Value src
Definition: avisynth_c.h:482
int offset
The offset relative to the context structure where the option value is stored.
Definition: opt.h:268
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:59
union AVOption::@192 default_val
the default value for scalar options
int av_opt_set_dict(void *obj, struct AVDictionary **options)
Set all the options from a given dictionary on an object.
Definition: opt.c:1476
int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
Show the obj options.
Definition: opt.c:1166
attribute_deprecated int64_t av_get_int(void *obj, const char *name, const AVOption **o_out)
Definition: opt.c:811
void * buf
Definition: avisynth_c.h:553
int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout)
Definition: opt.c:925
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:276
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
attribute_deprecated const AVOption * av_next_option(FF_CONST_AVUTIL55 void *obj, const AVOption *last)
Definition: opt.c:45
static int flags
Definition: cpu.c:47
#define attribute_deprecated
Definition: attributes.h:86
void av_opt_free(void *obj)
Free all allocated objects in obj.
Definition: opt.c:1432
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:1629
double value_min
Value range.
Definition: opt.h:323
rational numbers
int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
Definition: opt.c:835
int nb_ranges
Number of ranges per component.
Definition: opt.h:374
#define MKBETAG(a, b, c, d)
Definition: common.h:331
List of AVOptionRange structs.
Definition: opt.h:339
pixel format definitions
attribute_deprecated int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out)
Set the field of obj with the given name to value.
Definition: opt.c:360
int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
Definition: opt.c:689
enum AVOptionType type
Definition: opt.h:269
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:1358
int64_t i64
Definition: opt.h:275
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:959
#define FF_CONST_AVUTIL55
Definition: version.h:140
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:1487
int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags)
Definition: opt.c:609
AVPixelFormat
Pixel format.
Definition: pixfmt.h:61
int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags)
Definition: opt.c:536
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:369
GLuint buffer
Definition: opengl_enc.c:102
const char * name
Definition: opengl_enc.c:103
int nb_components
Number of componentes.
Definition: opt.h:378
int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out)
Definition: opt.c:863