1 | /* |
2 | * AVOptions |
3 | * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> |
4 | * |
5 | * This file is part of FFmpeg. |
6 | * |
7 | * FFmpeg is free software; you can redistribute it and/or |
8 | * modify it under the terms of the GNU Lesser General Public |
9 | * License as published by the Free Software Foundation; either |
10 | * version 2.1 of the License, or (at your option) any later version. |
11 | * |
12 | * FFmpeg is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | * Lesser General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU Lesser General Public |
18 | * License along with FFmpeg; if not, write to the Free Software |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
20 | */ |
21 | |
22 | #ifndef AVUTIL_OPT_H |
23 | #define AVUTIL_OPT_H |
24 | |
25 | /** |
26 | * @file |
27 | * AVOptions |
28 | */ |
29 | |
30 | #include "rational.h" |
31 | #include "avutil.h" |
32 | #include "channel_layout.h" |
33 | #include "dict.h" |
34 | #include "log.h" |
35 | #include "pixfmt.h" |
36 | #include "samplefmt.h" |
37 | |
38 | /** |
39 | * @defgroup avoptions AVOptions |
40 | * @ingroup lavu_data |
41 | * @{ |
42 | * AVOptions provide a generic system to declare options on arbitrary structs |
43 | * ("objects"). An option can have a help text, a type and a range of possible |
44 | * values. Options may then be enumerated, read and written to. |
45 | * |
46 | * @section avoptions_implement Implementing AVOptions |
47 | * This section describes how to add AVOptions capabilities to a struct. |
48 | * |
49 | * All AVOptions-related information is stored in an AVClass. Therefore |
50 | * the first member of the struct should be a pointer to an AVClass describing it. |
51 | * The option field of the AVClass must be set to a NULL-terminated static array |
52 | * of AVOptions. Each AVOption must have a non-empty name, a type, a default |
53 | * value and for number-type AVOptions also a range of allowed values. It must |
54 | * also declare an offset in bytes from the start of the struct, where the field |
55 | * associated with this AVOption is located. Other fields in the AVOption struct |
56 | * should also be set when applicable, but are not required. |
57 | * |
58 | * The following example illustrates an AVOptions-enabled struct: |
59 | * @code |
60 | * typedef struct test_struct { |
61 | * const AVClass *class; |
62 | * int int_opt; |
63 | * char *str_opt; |
64 | * uint8_t *bin_opt; |
65 | * int bin_len; |
66 | * } test_struct; |
67 | * |
68 | * static const AVOption test_options[] = { |
69 | * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt), |
70 | * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX }, |
71 | * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt), |
72 | * AV_OPT_TYPE_STRING }, |
73 | * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt), |
74 | * AV_OPT_TYPE_BINARY }, |
75 | * { NULL }, |
76 | * }; |
77 | * |
78 | * static const AVClass test_class = { |
79 | * .class_name = "test class", |
80 | * .item_name = av_default_item_name, |
81 | * .option = test_options, |
82 | * .version = LIBAVUTIL_VERSION_INT, |
83 | * }; |
84 | * @endcode |
85 | * |
86 | * Next, when allocating your struct, you must ensure that the AVClass pointer |
87 | * is set to the correct value. Then, av_opt_set_defaults() can be called to |
88 | * initialize defaults. After that the struct is ready to be used with the |
89 | * AVOptions API. |
90 | * |
91 | * When cleaning up, you may use the av_opt_free() function to automatically |
92 | * free all the allocated string and binary options. |
93 | * |
94 | * Continuing with the above example: |
95 | * |
96 | * @code |
97 | * test_struct *alloc_test_struct(void) |
98 | * { |
99 | * test_struct *ret = av_mallocz(sizeof(*ret)); |
100 | * ret->class = &test_class; |
101 | * av_opt_set_defaults(ret); |
102 | * return ret; |
103 | * } |
104 | * void free_test_struct(test_struct **foo) |
105 | * { |
106 | * av_opt_free(*foo); |
107 | * av_freep(foo); |
108 | * } |
109 | * @endcode |
110 | * |
111 | * @subsection avoptions_implement_nesting Nesting |
112 | * It may happen that an AVOptions-enabled struct contains another |
113 | * AVOptions-enabled struct as a member (e.g. AVCodecContext in |
114 | * libavcodec exports generic options, while its priv_data field exports |
115 | * codec-specific options). In such a case, it is possible to set up the |
116 | * parent struct to export a child's options. To do that, simply |
117 | * implement AVClass.child_next() and AVClass.child_class_iterate() in the |
118 | * parent struct's AVClass. |
119 | * Assuming that the test_struct from above now also contains a |
120 | * child_struct field: |
121 | * |
122 | * @code |
123 | * typedef struct child_struct { |
124 | * AVClass *class; |
125 | * int flags_opt; |
126 | * } child_struct; |
127 | * static const AVOption child_opts[] = { |
128 | * { "test_flags", "This is a test option of flags type.", |
129 | * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX }, |
130 | * { NULL }, |
131 | * }; |
132 | * static const AVClass child_class = { |
133 | * .class_name = "child class", |
134 | * .item_name = av_default_item_name, |
135 | * .option = child_opts, |
136 | * .version = LIBAVUTIL_VERSION_INT, |
137 | * }; |
138 | * |
139 | * void *child_next(void *obj, void *prev) |
140 | * { |
141 | * test_struct *t = obj; |
142 | * if (!prev && t->child_struct) |
143 | * return t->child_struct; |
144 | * return NULL |
145 | * } |
146 | * const AVClass child_class_iterate(void **iter) |
147 | * { |
148 | * const AVClass *c = *iter ? NULL : &child_class; |
149 | * *iter = (void*)(uintptr_t)c; |
150 | * return c; |
151 | * } |
152 | * @endcode |
153 | * Putting child_next() and child_class_iterate() as defined above into |
154 | * test_class will now make child_struct's options accessible through |
155 | * test_struct (again, proper setup as described above needs to be done on |
156 | * child_struct right after it is created). |
157 | * |
158 | * From the above example it might not be clear why both child_next() |
159 | * and child_class_iterate() are needed. The distinction is that child_next() |
160 | * iterates over actually existing objects, while child_class_iterate() |
161 | * iterates over all possible child classes. E.g. if an AVCodecContext |
162 | * was initialized to use a codec which has private options, then its |
163 | * child_next() will return AVCodecContext.priv_data and finish |
164 | * iterating. OTOH child_class_iterate() on AVCodecContext.av_class will |
165 | * iterate over all available codecs with private options. |
166 | * |
167 | * @subsection avoptions_implement_named_constants Named constants |
168 | * It is possible to create named constants for options. Simply set the unit |
169 | * field of the option the constants should apply to a string and |
170 | * create the constants themselves as options of type AV_OPT_TYPE_CONST |
171 | * with their unit field set to the same string. |
172 | * Their default_val field should contain the value of the named |
173 | * constant. |
174 | * For example, to add some named constants for the test_flags option |
175 | * above, put the following into the child_opts array: |
176 | * @code |
177 | * { "test_flags", "This is a test option of flags type.", |
178 | * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" }, |
179 | * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" }, |
180 | * @endcode |
181 | * |
182 | * @section avoptions_use Using AVOptions |
183 | * This section deals with accessing options in an AVOptions-enabled struct. |
184 | * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or |
185 | * AVFormatContext in libavformat. |
186 | * |
187 | * @subsection avoptions_use_examine Examining AVOptions |
188 | * The basic functions for examining options are av_opt_next(), which iterates |
189 | * over all options defined for one object, and av_opt_find(), which searches |
190 | * for an option with the given name. |
191 | * |
192 | * The situation is more complicated with nesting. An AVOptions-enabled struct |
193 | * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag |
194 | * to av_opt_find() will make the function search children recursively. |
195 | * |
196 | * For enumerating there are basically two cases. The first is when you want to |
197 | * get all options that may potentially exist on the struct and its children |
198 | * (e.g. when constructing documentation). In that case you should call |
199 | * av_opt_child_class_iterate() recursively on the parent struct's AVClass. The |
200 | * second case is when you have an already initialized struct with all its |
201 | * children and you want to get all options that can be actually written or read |
202 | * from it. In that case you should call av_opt_child_next() recursively (and |
203 | * av_opt_next() on each result). |
204 | * |
205 | * @subsection avoptions_use_get_set Reading and writing AVOptions |
206 | * When setting options, you often have a string read directly from the |
207 | * user. In such a case, simply passing it to av_opt_set() is enough. For |
208 | * non-string type options, av_opt_set() will parse the string according to the |
209 | * option type. |
210 | * |
211 | * Similarly av_opt_get() will read any option type and convert it to a string |
212 | * which will be returned. Do not forget that the string is allocated, so you |
213 | * have to free it with av_free(). |
214 | * |
215 | * In some cases it may be more convenient to put all options into an |
216 | * AVDictionary and call av_opt_set_dict() on it. A specific case of this |
217 | * are the format/codec open functions in lavf/lavc which take a dictionary |
218 | * filled with option as a parameter. This makes it possible to set some options |
219 | * that cannot be set otherwise, since e.g. the input file format is not known |
220 | * before the file is actually opened. |
221 | */ |
222 | |
223 | enum AVOptionType{ |
224 | AV_OPT_TYPE_FLAGS, |
225 | AV_OPT_TYPE_INT, |
226 | AV_OPT_TYPE_INT64, |
227 | AV_OPT_TYPE_DOUBLE, |
228 | AV_OPT_TYPE_FLOAT, |
229 | AV_OPT_TYPE_STRING, |
230 | AV_OPT_TYPE_RATIONAL, |
231 | AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length |
232 | AV_OPT_TYPE_DICT, |
233 | AV_OPT_TYPE_UINT64, |
234 | AV_OPT_TYPE_CONST, |
235 | AV_OPT_TYPE_IMAGE_SIZE, ///< offset must point to two consecutive integers |
236 | AV_OPT_TYPE_PIXEL_FMT, |
237 | AV_OPT_TYPE_SAMPLE_FMT, |
238 | AV_OPT_TYPE_VIDEO_RATE, ///< offset must point to AVRational |
239 | AV_OPT_TYPE_DURATION, |
240 | AV_OPT_TYPE_COLOR, |
241 | #if FF_API_OLD_CHANNEL_LAYOUT |
242 | AV_OPT_TYPE_CHANNEL_LAYOUT, |
243 | #endif |
244 | AV_OPT_TYPE_BOOL, |
245 | AV_OPT_TYPE_CHLAYOUT, |
246 | }; |
247 | |
248 | /** |
249 | * AVOption |
250 | */ |
251 | typedef struct AVOption { |
252 | const char *name; |
253 | |
254 | /** |
255 | * short English help text |
256 | * @todo What about other languages? |
257 | */ |
258 | const char *help; |
259 | |
260 | /** |
261 | * The offset relative to the context structure where the option |
262 | * value is stored. It should be 0 for named constants. |
263 | */ |
264 | int offset; |
265 | enum AVOptionType type; |
266 | |
267 | /** |
268 | * the default value for scalar options |
269 | */ |
270 | union { |
271 | int64_t i64; |
272 | double dbl; |
273 | const char *str; |
274 | /* TODO those are unused now */ |
275 | AVRational q; |
276 | } default_val; |
277 | double min; ///< minimum valid value for the option |
278 | double max; ///< maximum valid value for the option |
279 | |
280 | int flags; |
281 | #define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding |
282 | #define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding |
283 | #define AV_OPT_FLAG_AUDIO_PARAM 8 |
284 | #define AV_OPT_FLAG_VIDEO_PARAM 16 |
285 | #define AV_OPT_FLAG_SUBTITLE_PARAM 32 |
286 | /** |
287 | * The option is intended for exporting values to the caller. |
288 | */ |
289 | #define AV_OPT_FLAG_EXPORT 64 |
290 | /** |
291 | * The option may not be set through the AVOptions API, only read. |
292 | * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set. |
293 | */ |
294 | #define AV_OPT_FLAG_READONLY 128 |
295 | #define AV_OPT_FLAG_BSF_PARAM (1<<8) ///< a generic parameter which can be set by the user for bit stream filtering |
296 | #define AV_OPT_FLAG_RUNTIME_PARAM (1<<15) ///< a generic parameter which can be set by the user at runtime |
297 | #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering |
298 | #define AV_OPT_FLAG_DEPRECATED (1<<17) ///< set if option is deprecated, users should refer to AVOption.help text for more information |
299 | #define AV_OPT_FLAG_CHILD_CONSTS (1<<18) ///< set if option constants can also reside in child objects |
300 | //FIXME think about enc-audio, ... style flags |
301 | |
302 | /** |
303 | * The logical unit to which the option belongs. Non-constant |
304 | * options and corresponding named constants share the same |
305 | * unit. May be NULL. |
306 | */ |
307 | const char *unit; |
308 | } AVOption; |
309 | |
310 | /** |
311 | * A single allowed range of values, or a single allowed value. |
312 | */ |
313 | typedef struct AVOptionRange { |
314 | const char *str; |
315 | /** |
316 | * Value range. |
317 | * For string ranges this represents the min/max length. |
318 | * For dimensions this represents the min/max pixel count or width/height in multi-component case. |
319 | */ |
320 | double value_min, value_max; |
321 | /** |
322 | * Value's component range. |
323 | * For string this represents the unicode range for chars, 0-127 limits to ASCII. |
324 | */ |
325 | double component_min, component_max; |
326 | /** |
327 | * Range flag. |
328 | * If set to 1 the struct encodes a range, if set to 0 a single value. |
329 | */ |
330 | int is_range; |
331 | } AVOptionRange; |
332 | |
333 | /** |
334 | * List of AVOptionRange structs. |
335 | */ |
336 | typedef struct AVOptionRanges { |
337 | /** |
338 | * Array of option ranges. |
339 | * |
340 | * Most of option types use just one component. |
341 | * Following describes multi-component option types: |
342 | * |
343 | * AV_OPT_TYPE_IMAGE_SIZE: |
344 | * component index 0: range of pixel count (width * height). |
345 | * component index 1: range of width. |
346 | * component index 2: range of height. |
347 | * |
348 | * @note To obtain multi-component version of this structure, user must |
349 | * provide AV_OPT_MULTI_COMPONENT_RANGE to av_opt_query_ranges or |
350 | * av_opt_query_ranges_default function. |
351 | * |
352 | * Multi-component range can be read as in following example: |
353 | * |
354 | * @code |
355 | * int range_index, component_index; |
356 | * AVOptionRanges *ranges; |
357 | * AVOptionRange *range[3]; //may require more than 3 in the future. |
358 | * av_opt_query_ranges(&ranges, obj, key, AV_OPT_MULTI_COMPONENT_RANGE); |
359 | * for (range_index = 0; range_index < ranges->nb_ranges; range_index++) { |
360 | * for (component_index = 0; component_index < ranges->nb_components; component_index++) |
361 | * range[component_index] = ranges->range[ranges->nb_ranges * component_index + range_index]; |
362 | * //do something with range here. |
363 | * } |
364 | * av_opt_freep_ranges(&ranges); |
365 | * @endcode |
366 | */ |
367 | AVOptionRange **range; |
368 | /** |
369 | * Number of ranges per component. |
370 | */ |
371 | int nb_ranges; |
372 | /** |
373 | * Number of componentes. |
374 | */ |
375 | int nb_components; |
376 | } AVOptionRanges; |
377 | |
378 | /** |
379 | * Show the obj options. |
380 | * |
381 | * @param req_flags requested flags for the options to show. Show only the |
382 | * options for which it is opt->flags & req_flags. |
383 | * @param rej_flags rejected flags for the options to show. Show only the |
384 | * options for which it is !(opt->flags & req_flags). |
385 | * @param av_log_obj log context to use for showing the options |
386 | */ |
387 | int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags); |
388 | |
389 | /** |
390 | * Set the values of all AVOption fields to their default values. |
391 | * |
392 | * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) |
393 | */ |
394 | void av_opt_set_defaults(void *s); |
395 | |
396 | /** |
397 | * Set the values of all AVOption fields to their default values. Only these |
398 | * AVOption fields for which (opt->flags & mask) == flags will have their |
399 | * default applied to s. |
400 | * |
401 | * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) |
402 | * @param mask combination of AV_OPT_FLAG_* |
403 | * @param flags combination of AV_OPT_FLAG_* |
404 | */ |
405 | void av_opt_set_defaults2(void *s, int mask, int flags); |
406 | |
407 | /** |
408 | * Parse the key/value pairs list in opts. For each key/value pair |
409 | * found, stores the value in the field in ctx that is named like the |
410 | * key. ctx must be an AVClass context, storing is done using |
411 | * AVOptions. |
412 | * |
413 | * @param opts options string to parse, may be NULL |
414 | * @param key_val_sep a 0-terminated list of characters used to |
415 | * separate key from value |
416 | * @param pairs_sep a 0-terminated list of characters used to separate |
417 | * two pairs from each other |
418 | * @return the number of successfully set key/value pairs, or a negative |
419 | * value corresponding to an AVERROR code in case of error: |
420 | * AVERROR(EINVAL) if opts cannot be parsed, |
421 | * the error code issued by av_opt_set() if a key/value pair |
422 | * cannot be set |
423 | */ |
424 | int av_set_options_string(void *ctx, const char *opts, |
425 | const char *key_val_sep, const char *pairs_sep); |
426 | |
427 | /** |
428 | * Parse the key-value pairs list in opts. For each key=value pair found, |
429 | * set the value of the corresponding option in ctx. |
430 | * |
431 | * @param ctx the AVClass object to set options on |
432 | * @param opts the options string, key-value pairs separated by a |
433 | * delimiter |
434 | * @param shorthand a NULL-terminated array of options names for shorthand |
435 | * notation: if the first field in opts has no key part, |
436 | * the key is taken from the first element of shorthand; |
437 | * then again for the second, etc., until either opts is |
438 | * finished, shorthand is finished or a named option is |
439 | * found; after that, all options must be named |
440 | * @param key_val_sep a 0-terminated list of characters used to separate |
441 | * key from value, for example '=' |
442 | * @param pairs_sep a 0-terminated list of characters used to separate |
443 | * two pairs from each other, for example ':' or ',' |
444 | * @return the number of successfully set key=value pairs, or a negative |
445 | * value corresponding to an AVERROR code in case of error: |
446 | * AVERROR(EINVAL) if opts cannot be parsed, |
447 | * the error code issued by av_set_string3() if a key/value pair |
448 | * cannot be set |
449 | * |
450 | * Options names must use only the following characters: a-z A-Z 0-9 - . / _ |
451 | * Separators must use characters distinct from option names and from each |
452 | * other. |
453 | */ |
454 | int av_opt_set_from_string(void *ctx, const char *opts, |
455 | const char *const *shorthand, |
456 | const char *key_val_sep, const char *pairs_sep); |
457 | /** |
458 | * Free all allocated objects in obj. |
459 | */ |
460 | void av_opt_free(void *obj); |
461 | |
462 | /** |
463 | * Check whether a particular flag is set in a flags field. |
464 | * |
465 | * @param field_name the name of the flag field option |
466 | * @param flag_name the name of the flag to check |
467 | * @return non-zero if the flag is set, zero if the flag isn't set, |
468 | * isn't of the right type, or the flags field doesn't exist. |
469 | */ |
470 | int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name); |
471 | |
472 | /** |
473 | * Set all the options from a given dictionary on an object. |
474 | * |
475 | * @param obj a struct whose first element is a pointer to AVClass |
476 | * @param options options to process. This dictionary will be freed and replaced |
477 | * by a new one containing all options not found in obj. |
478 | * Of course this new dictionary needs to be freed by caller |
479 | * with av_dict_free(). |
480 | * |
481 | * @return 0 on success, a negative AVERROR if some option was found in obj, |
482 | * but could not be set. |
483 | * |
484 | * @see av_dict_copy() |
485 | */ |
486 | int av_opt_set_dict(void *obj, struct AVDictionary **options); |
487 | |
488 | |
489 | /** |
490 | * Set all the options from a given dictionary on an object. |
491 | * |
492 | * @param obj a struct whose first element is a pointer to AVClass |
493 | * @param options options to process. This dictionary will be freed and replaced |
494 | * by a new one containing all options not found in obj. |
495 | * Of course this new dictionary needs to be freed by caller |
496 | * with av_dict_free(). |
497 | * @param search_flags A combination of AV_OPT_SEARCH_*. |
498 | * |
499 | * @return 0 on success, a negative AVERROR if some option was found in obj, |
500 | * but could not be set. |
501 | * |
502 | * @see av_dict_copy() |
503 | */ |
504 | int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags); |
505 | |
506 | /** |
507 | * Extract a key-value pair from the beginning of a string. |
508 | * |
509 | * @param ropts pointer to the options string, will be updated to |
510 | * point to the rest of the string (one of the pairs_sep |
511 | * or the final NUL) |
512 | * @param key_val_sep a 0-terminated list of characters used to separate |
513 | * key from value, for example '=' |
514 | * @param pairs_sep a 0-terminated list of characters used to separate |
515 | * two pairs from each other, for example ':' or ',' |
516 | * @param flags flags; see the AV_OPT_FLAG_* values below |
517 | * @param rkey parsed key; must be freed using av_free() |
518 | * @param rval parsed value; must be freed using av_free() |
519 | * |
520 | * @return >=0 for success, or a negative value corresponding to an |
521 | * AVERROR code in case of error; in particular: |
522 | * AVERROR(EINVAL) if no key is present |
523 | * |
524 | */ |
525 | int av_opt_get_key_value(const char **ropts, |
526 | const char *key_val_sep, const char *pairs_sep, |
527 | unsigned flags, |
528 | char **rkey, char **rval); |
529 | |
530 | enum { |
531 | |
532 | /** |
533 | * Accept to parse a value without a key; the key will then be returned |
534 | * as NULL. |
535 | */ |
536 | AV_OPT_FLAG_IMPLICIT_KEY = 1, |
537 | }; |
538 | |
539 | /** |
540 | * @defgroup opt_eval_funcs Evaluating option strings |
541 | * @{ |
542 | * This group of functions can be used to evaluate option strings |
543 | * and get numbers out of them. They do the same thing as av_opt_set(), |
544 | * except the result is written into the caller-supplied pointer. |
545 | * |
546 | * @param obj a struct whose first element is a pointer to AVClass. |
547 | * @param o an option for which the string is to be evaluated. |
548 | * @param val string to be evaluated. |
549 | * @param *_out value of the string will be written here. |
550 | * |
551 | * @return 0 on success, a negative number on failure. |
552 | */ |
553 | int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out); |
554 | int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out); |
555 | int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out); |
556 | int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out); |
557 | int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out); |
558 | int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out); |
559 | /** |
560 | * @} |
561 | */ |
562 | |
563 | #define AV_OPT_SEARCH_CHILDREN (1 << 0) /**< Search in possible children of the |
564 | given object first. */ |
565 | /** |
566 | * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass |
567 | * instead of a required pointer to a struct containing AVClass. This is |
568 | * useful for searching for options without needing to allocate the corresponding |
569 | * object. |
570 | */ |
571 | #define AV_OPT_SEARCH_FAKE_OBJ (1 << 1) |
572 | |
573 | /** |
574 | * In av_opt_get, return NULL if the option has a pointer type and is set to NULL, |
575 | * rather than returning an empty string. |
576 | */ |
577 | #define AV_OPT_ALLOW_NULL (1 << 2) |
578 | |
579 | /** |
580 | * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than |
581 | * one component for certain option types. |
582 | * @see AVOptionRanges for details. |
583 | */ |
584 | #define AV_OPT_MULTI_COMPONENT_RANGE (1 << 12) |
585 | |
586 | /** |
587 | * Look for an option in an object. Consider only options which |
588 | * have all the specified flags set. |
589 | * |
590 | * @param[in] obj A pointer to a struct whose first element is a |
591 | * pointer to an AVClass. |
592 | * Alternatively a double pointer to an AVClass, if |
593 | * AV_OPT_SEARCH_FAKE_OBJ search flag is set. |
594 | * @param[in] name The name of the option to look for. |
595 | * @param[in] unit When searching for named constants, name of the unit |
596 | * it belongs to. |
597 | * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). |
598 | * @param search_flags A combination of AV_OPT_SEARCH_*. |
599 | * |
600 | * @return A pointer to the option found, or NULL if no option |
601 | * was found. |
602 | * |
603 | * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable |
604 | * directly with av_opt_set(). Use special calls which take an options |
605 | * AVDictionary (e.g. avformat_open_input()) to set options found with this |
606 | * flag. |
607 | */ |
608 | const AVOption *av_opt_find(void *obj, const char *name, const char *unit, |
609 | int opt_flags, int search_flags); |
610 | |
611 | /** |
612 | * Look for an option in an object. Consider only options which |
613 | * have all the specified flags set. |
614 | * |
615 | * @param[in] obj A pointer to a struct whose first element is a |
616 | * pointer to an AVClass. |
617 | * Alternatively a double pointer to an AVClass, if |
618 | * AV_OPT_SEARCH_FAKE_OBJ search flag is set. |
619 | * @param[in] name The name of the option to look for. |
620 | * @param[in] unit When searching for named constants, name of the unit |
621 | * it belongs to. |
622 | * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). |
623 | * @param search_flags A combination of AV_OPT_SEARCH_*. |
624 | * @param[out] target_obj if non-NULL, an object to which the option belongs will be |
625 | * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present |
626 | * in search_flags. This parameter is ignored if search_flags contain |
627 | * AV_OPT_SEARCH_FAKE_OBJ. |
628 | * |
629 | * @return A pointer to the option found, or NULL if no option |
630 | * was found. |
631 | */ |
632 | const AVOption *av_opt_find2(void *obj, const char *name, const char *unit, |
633 | int opt_flags, int search_flags, void **target_obj); |
634 | |
635 | /** |
636 | * Iterate over all AVOptions belonging to obj. |
637 | * |
638 | * @param obj an AVOptions-enabled struct or a double pointer to an |
639 | * AVClass describing it. |
640 | * @param prev result of the previous call to av_opt_next() on this object |
641 | * or NULL |
642 | * @return next AVOption or NULL |
643 | */ |
644 | const AVOption *av_opt_next(const void *obj, const AVOption *prev); |
645 | |
646 | /** |
647 | * Iterate over AVOptions-enabled children of obj. |
648 | * |
649 | * @param prev result of a previous call to this function or NULL |
650 | * @return next AVOptions-enabled child or NULL |
651 | */ |
652 | void *av_opt_child_next(void *obj, void *prev); |
653 | |
654 | /** |
655 | * Iterate over potential AVOptions-enabled children of parent. |
656 | * |
657 | * @param iter a pointer where iteration state is stored. |
658 | * @return AVClass corresponding to next potential child or NULL |
659 | */ |
660 | const AVClass *av_opt_child_class_iterate(const AVClass *parent, void **iter); |
661 | |
662 | /** |
663 | * @defgroup opt_set_funcs Option setting functions |
664 | * @{ |
665 | * Those functions set the field of obj with the given name to value. |
666 | * |
667 | * @param[in] obj A struct whose first element is a pointer to an AVClass. |
668 | * @param[in] name the name of the field to set |
669 | * @param[in] val The value to set. In case of av_opt_set() if the field is not |
670 | * of a string type, then the given string is parsed. |
671 | * SI postfixes and some named scalars are supported. |
672 | * If the field is of a numeric type, it has to be a numeric or named |
673 | * scalar. Behavior with more than one scalar and +- infix operators |
674 | * is undefined. |
675 | * If the field is of a flags type, it has to be a sequence of numeric |
676 | * scalars or named flags separated by '+' or '-'. Prefixing a flag |
677 | * with '+' causes it to be set without affecting the other flags; |
678 | * similarly, '-' unsets a flag. |
679 | * If the field is of a dictionary type, it has to be a ':' separated list of |
680 | * key=value parameters. Values containing ':' special characters must be |
681 | * escaped. |
682 | * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN |
683 | * is passed here, then the option may be set on a child of obj. |
684 | * |
685 | * @return 0 if the value has been set, or an AVERROR code in case of |
686 | * error: |
687 | * AVERROR_OPTION_NOT_FOUND if no matching option exists |
688 | * AVERROR(ERANGE) if the value is out of range |
689 | * AVERROR(EINVAL) if the value is not valid |
690 | */ |
691 | int av_opt_set (void *obj, const char *name, const char *val, int search_flags); |
692 | int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags); |
693 | int av_opt_set_double (void *obj, const char *name, double val, int search_flags); |
694 | int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags); |
695 | int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags); |
696 | int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags); |
697 | int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags); |
698 | int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags); |
699 | int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags); |
700 | #if FF_API_OLD_CHANNEL_LAYOUT |
701 | attribute_deprecated |
702 | int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags); |
703 | #endif |
704 | int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *layout, int search_flags); |
705 | /** |
706 | * @note Any old dictionary present is discarded and replaced with a copy of the new one. The |
707 | * caller still owns val is and responsible for freeing it. |
708 | */ |
709 | int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags); |
710 | |
711 | /** |
712 | * Set a binary option to an integer list. |
713 | * |
714 | * @param obj AVClass object to set options on |
715 | * @param name name of the binary option |
716 | * @param val pointer to an integer list (must have the correct type with |
717 | * regard to the contents of the list) |
718 | * @param term list terminator (usually 0 or -1) |
719 | * @param flags search flags |
720 | */ |
721 | #define av_opt_set_int_list(obj, name, val, term, flags) \ |
722 | (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \ |
723 | AVERROR(EINVAL) : \ |
724 | av_opt_set_bin(obj, name, (const uint8_t *)(val), \ |
725 | av_int_list_length(val, term) * sizeof(*(val)), flags)) |
726 | |
727 | /** |
728 | * @} |
729 | */ |
730 | |
731 | /** |
732 | * @defgroup opt_get_funcs Option getting functions |
733 | * @{ |
734 | * Those functions get a value of the option with the given name from an object. |
735 | * |
736 | * @param[in] obj a struct whose first element is a pointer to an AVClass. |
737 | * @param[in] name name of the option to get. |
738 | * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN |
739 | * is passed here, then the option may be found in a child of obj. |
740 | * @param[out] out_val value of the option will be written here |
741 | * @return >=0 on success, a negative error code otherwise |
742 | */ |
743 | /** |
744 | * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller |
745 | * |
746 | * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the |
747 | * option is of type AV_OPT_TYPE_STRING, AV_OPT_TYPE_BINARY or AV_OPT_TYPE_DICT |
748 | * and is set to NULL, *out_val will be set to NULL instead of an allocated |
749 | * empty string. |
750 | */ |
751 | int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val); |
752 | int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val); |
753 | int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val); |
754 | int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val); |
755 | int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out); |
756 | int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt); |
757 | int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt); |
758 | int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val); |
759 | #if FF_API_OLD_CHANNEL_LAYOUT |
760 | attribute_deprecated |
761 | int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout); |
762 | #endif |
763 | int av_opt_get_chlayout(void *obj, const char *name, int search_flags, AVChannelLayout *layout); |
764 | /** |
765 | * @param[out] out_val The returned dictionary is a copy of the actual value and must |
766 | * be freed with av_dict_free() by the caller |
767 | */ |
768 | int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val); |
769 | /** |
770 | * @} |
771 | */ |
772 | /** |
773 | * Gets a pointer to the requested field in a struct. |
774 | * This function allows accessing a struct even when its fields are moved or |
775 | * renamed since the application making the access has been compiled, |
776 | * |
777 | * @returns a pointer to the field, it can be cast to the correct type and read |
778 | * or written to. |
779 | */ |
780 | void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name); |
781 | |
782 | /** |
783 | * Free an AVOptionRanges struct and set it to NULL. |
784 | */ |
785 | void av_opt_freep_ranges(AVOptionRanges **ranges); |
786 | |
787 | /** |
788 | * Get a list of allowed ranges for the given option. |
789 | * |
790 | * The returned list may depend on other fields in obj like for example profile. |
791 | * |
792 | * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored |
793 | * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance |
794 | * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges |
795 | * |
796 | * The result must be freed with av_opt_freep_ranges. |
797 | * |
798 | * @return number of compontents returned on success, a negative errro code otherwise |
799 | */ |
800 | int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags); |
801 | |
802 | /** |
803 | * Copy options from src object into dest object. |
804 | * |
805 | * The underlying AVClass of both src and dest must coincide. The guarantee |
806 | * below does not apply if this is not fulfilled. |
807 | * |
808 | * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object. |
809 | * Original memory allocated for such options is freed unless both src and dest options points to the same memory. |
810 | * |
811 | * Even on error it is guaranteed that allocated options from src and dest |
812 | * no longer alias each other afterwards; in particular calling av_opt_free() |
813 | * on both src and dest is safe afterwards if dest has been memdup'ed from src. |
814 | * |
815 | * @param dest Object to copy from |
816 | * @param src Object to copy into |
817 | * @return 0 on success, negative on error |
818 | */ |
819 | int av_opt_copy(void *dest, const void *src); |
820 | |
821 | /** |
822 | * Get a default list of allowed ranges for the given option. |
823 | * |
824 | * This list is constructed without using the AVClass.query_ranges() callback |
825 | * and can be used as fallback from within the callback. |
826 | * |
827 | * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored |
828 | * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance |
829 | * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges |
830 | * |
831 | * The result must be freed with av_opt_free_ranges. |
832 | * |
833 | * @return number of compontents returned on success, a negative errro code otherwise |
834 | */ |
835 | int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags); |
836 | |
837 | /** |
838 | * Check if given option is set to its default value. |
839 | * |
840 | * Options o must belong to the obj. This function must not be called to check child's options state. |
841 | * @see av_opt_is_set_to_default_by_name(). |
842 | * |
843 | * @param obj AVClass object to check option on |
844 | * @param o option to be checked |
845 | * @return >0 when option is set to its default, |
846 | * 0 when option is not set its default, |
847 | * <0 on error |
848 | */ |
849 | int av_opt_is_set_to_default(void *obj, const AVOption *o); |
850 | |
851 | /** |
852 | * Check if given option is set to its default value. |
853 | * |
854 | * @param obj AVClass object to check option on |
855 | * @param name option name |
856 | * @param search_flags combination of AV_OPT_SEARCH_* |
857 | * @return >0 when option is set to its default, |
858 | * 0 when option is not set its default, |
859 | * <0 on error |
860 | */ |
861 | int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags); |
862 | |
863 | |
864 | #define AV_OPT_SERIALIZE_SKIP_DEFAULTS 0x00000001 ///< Serialize options that are not set to default values only. |
865 | #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT 0x00000002 ///< Serialize options that exactly match opt_flags only. |
866 | |
867 | /** |
868 | * Serialize object's options. |
869 | * |
870 | * Create a string containing object's serialized options. |
871 | * Such string may be passed back to av_opt_set_from_string() in order to restore option values. |
872 | * A key/value or pairs separator occurring in the serialized value or |
873 | * name string are escaped through the av_escape() function. |
874 | * |
875 | * @param[in] obj AVClass object to serialize |
876 | * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG) |
877 | * @param[in] flags combination of AV_OPT_SERIALIZE_* flags |
878 | * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options. |
879 | * Buffer must be freed by the caller when is no longer needed. |
880 | * @param[in] key_val_sep character used to separate key from value |
881 | * @param[in] pairs_sep character used to separate two pairs from each other |
882 | * @return >= 0 on success, negative on error |
883 | * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same. |
884 | */ |
885 | int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer, |
886 | const char key_val_sep, const char pairs_sep); |
887 | /** |
888 | * @} |
889 | */ |
890 | |
891 | #endif /* AVUTIL_OPT_H */ |
892 | |