1 /*

     2  * AVOptions

     3  * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>

     4  *

     5  * This file is part of Libav.

     6  *

     7  * Libav 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  * Libav 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 Libav; 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 

    35 /**

    36  * @defgroup avoptions AVOptions

    37  * @ingroup lavu_data

    38  * @{

    39  * AVOptions provide a generic system to declare options on arbitrary structs

    40  * ("objects"). An option can have a help text, a type and a range of possible

    41  * values. Options may then be enumerated, read and written to.

    42  *

    43  * @section avoptions_implement Implementing AVOptions

    44  * This section describes how to add AVOptions capabilities to a struct.

    45  *

    46  * All AVOptions-related information is stored in an AVClass. Therefore

    47  * the first member of the struct must be a pointer to an AVClass describing it.

    48  * The option field of the AVClass must be set to a NULL-terminated static array

    49  * of AVOptions. Each AVOption must have a non-empty name, a type, a default

    50  * value and for number-type AVOptions also a range of allowed values. It must

    51  * also declare an offset in bytes from the start of the struct, where the field

    52  * associated with this AVOption is located. Other fields in the AVOption struct

    53  * should also be set when applicable, but are not required.

    54  *

    55  * The following example illustrates an AVOptions-enabled struct:

    56  * @code

    57  * typedef struct test_struct {

    58  *     AVClass *class;

    59  *     int      int_opt;

    60  *     char    *str_opt;

    61  *     uint8_t *bin_opt;

    62  *     int      bin_len;

    63  * } test_struct;

    64  *

    65  * static const AVOption options[] = {

    66  *   { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),

    67  *     AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },

    68  *   { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),

    69  *     AV_OPT_TYPE_STRING },

    70  *   { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),

    71  *     AV_OPT_TYPE_BINARY },

    72  *   { NULL },

    73  * };

    74  *

    75  * static const AVClass test_class = {

    76  *     .class_name = "test class",

    77  *     .item_name  = av_default_item_name,

    78  *     .option     = options,

    79  *     .version    = LIBAVUTIL_VERSION_INT,

    80  * };

    81  * @endcode

    82  *

    83  * Next, when allocating your struct, you must ensure that the AVClass pointer

    84  * is set to the correct value. Then, av_opt_set_defaults() must be called to

    85  * initialize defaults. After that the struct is ready to be used with the

    86  * AVOptions API.

    87  *

    88  * When cleaning up, you may use the av_opt_free() function to automatically

    89  * free all the allocated string and binary options.

    90  *

    91  * Continuing with the above example:

    92  *

    93  * @code

    94  * test_struct *alloc_test_struct(void)

    95  * {

    96  *     test_struct *ret = av_malloc(sizeof(*ret));

    97  *     ret->class = &test_class;

    98  *     av_opt_set_defaults(ret);

    99  *     return ret;

   100  * }

   101  * void free_test_struct(test_struct **foo)

   102  * {

   103  *     av_opt_free(*foo);

   104  *     av_freep(foo);

   105  * }

   106  * @endcode

   107  *

   108  * @subsection avoptions_implement_nesting Nesting

   109  *      It may happen that an AVOptions-enabled struct contains another

   110  *      AVOptions-enabled struct as a member (e.g. AVCodecContext in

   111  *      libavcodec exports generic options, while its priv_data field exports

   112  *      codec-specific options). In such a case, it is possible to set up the

   113  *      parent struct to export a child's options. To do that, simply

   114  *      implement AVClass.child_next() and AVClass.child_class_next() in the

   115  *      parent struct's AVClass.

   116  *      Assuming that the test_struct from above now also contains a

   117  *      child_struct field:

   118  *

   119  *      @code

   120  *      typedef struct child_struct {

   121  *          AVClass *class;

   122  *          int flags_opt;

   123  *      } child_struct;

   124  *      static const AVOption child_opts[] = {

   125  *          { "test_flags", "This is a test option of flags type.",

   126  *            offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },

   127  *          { NULL },

   128  *      };

   129  *      static const AVClass child_class = {

   130  *          .class_name = "child class",

   131  *          .item_name  = av_default_item_name,

   132  *          .option     = child_opts,

   133  *          .version    = LIBAVUTIL_VERSION_INT,

   134  *      };

   135  *

   136  *      void *child_next(void *obj, void *prev)

   137  *      {

   138  *          test_struct *t = obj;

   139  *          if (!prev && t->child_struct)

   140  *              return t->child_struct;

   141  *          return NULL

   142  *      }

   143  *      const AVClass child_class_next(const AVClass *prev)

   144  *      {

   145  *          return prev ? NULL : &child_class;

   146  *      }

   147  *      @endcode

   148  *      Putting child_next() and child_class_next() as defined above into

   149  *      test_class will now make child_struct's options accessible through

   150  *      test_struct (again, proper setup as described above needs to be done on

   151  *      child_struct right after it is created).

   152  *

   153  *      From the above example it might not be clear why both child_next()

   154  *      and child_class_next() are needed. The distinction is that child_next()

   155  *      iterates over actually existing objects, while child_class_next()

   156  *      iterates over all possible child classes. E.g. if an AVCodecContext

   157  *      was initialized to use a codec which has private options, then its

   158  *      child_next() will return AVCodecContext.priv_data and finish

   159  *      iterating. OTOH child_class_next() on AVCodecContext.av_class will

   160  *      iterate over all available codecs with private options.

   161  *

   162  * @subsection avoptions_implement_named_constants Named constants

   163  *      It is possible to create named constants for options. Simply set the unit

   164  *      field of the option the constants should apply to to a string and

   165  *      create the constants themselves as options of type AV_OPT_TYPE_CONST

   166  *      with their unit field set to the same string.

   167  *      Their default_val field should contain the value of the named

   168  *      constant.

   169  *      For example, to add some named constants for the test_flags option

   170  *      above, put the following into the child_opts array:

   171  *      @code

   172  *      { "test_flags", "This is a test option of flags type.",

   173  *        offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },

   174  *      { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },

   175  *      @endcode

   176  *

   177  * @section avoptions_use Using AVOptions

   178  * This section deals with accessing options in an AVOptions-enabled struct.

   179  * Such structs in Libav are e.g. AVCodecContext in libavcodec or

   180  * AVFormatContext in libavformat.

   181  *

   182  * @subsection avoptions_use_examine Examining AVOptions

   183  * The basic functions for examining options are av_opt_next(), which iterates

   184  * over all options defined for one object, and av_opt_find(), which searches

   185  * for an option with the given name.

   186  *

   187  * The situation is more complicated with nesting. An AVOptions-enabled struct

   188  * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag

   189  * to av_opt_find() will make the function search children recursively.

   190  *

   191  * For enumerating there are basically two cases. The first is when you want to

   192  * get all options that may potentially exist on the struct and its children

   193  * (e.g.  when constructing documentation). In that case you should call

   194  * av_opt_child_class_next() recursively on the parent struct's AVClass.  The

   195  * second case is when you have an already initialized struct with all its

   196  * children and you want to get all options that can be actually written or read

   197  * from it. In that case you should call av_opt_child_next() recursively (and

   198  * av_opt_next() on each result).

   199  *

   200  * @subsection avoptions_use_get_set Reading and writing AVOptions

   201  * When setting options, you often have a string read directly from the

   202  * user. In such a case, simply passing it to av_opt_set() is enough. For

   203  * non-string type options, av_opt_set() will parse the string according to the

   204  * option type.

   205  *

   206  * Similarly av_opt_get() will read any option type and convert it to a string

   207  * which will be returned. Do not forget that the string is allocated, so you

   208  * have to free it with av_free().

   209  *

   210  * In some cases it may be more convenient to put all options into an

   211  * AVDictionary and call av_opt_set_dict() on it. A specific case of this

   212  * are the format/codec open functions in lavf/lavc which take a dictionary

   213  * filled with option as a parameter. This allows to set some options

   214  * that cannot be set otherwise, since e.g. the input file format is not known

   215  * before the file is actually opened.

   216  */

   217 

   218 enum AVOptionType{

   219     AV_OPT_TYPE_FLAGS,

   220     AV_OPT_TYPE_INT,

   221     AV_OPT_TYPE_INT64,

   222     AV_OPT_TYPE_DOUBLE,

   223     AV_OPT_TYPE_FLOAT,

   224     AV_OPT_TYPE_STRING,

   225     AV_OPT_TYPE_RATIONAL,

   226     AV_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length

   227     AV_OPT_TYPE_CONST = 128,

   228 #if FF_API_OLD_AVOPTIONS

   229     FF_OPT_TYPE_FLAGS = 0,

   230     FF_OPT_TYPE_INT,

   231     FF_OPT_TYPE_INT64,

   232     FF_OPT_TYPE_DOUBLE,

   233     FF_OPT_TYPE_FLOAT,

   234     FF_OPT_TYPE_STRING,

   235     FF_OPT_TYPE_RATIONAL,

   236     FF_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length

   237     FF_OPT_TYPE_CONST=128,

   238 #endif

   239 };

   240 

   241 /**

   242  * AVOption

   243  */

   244 typedef struct AVOption {

   245     const char *name;

   246 

   247     /**

   248      * short English help text

   249      * @todo What about other languages?

   250      */

   251     const char *help;

   252 

   253     /**

   254      * The offset relative to the context structure where the option

   255      * value is stored. It should be 0 for named constants.

   256      */

   257     int offset;

   258     enum AVOptionType type;

   259 

   260     /**

   261      * the default value for scalar options

   262      */

   263     union {

   264         int64_t i64;

   265         double dbl;

   266         const char *str;

   267         /* TODO those are unused now */

   268         AVRational q;

   269     } default_val;

   270     double min;                 ///< minimum valid value for the option

   271     double max;                 ///< maximum valid value for the option

   272 

   273     int flags;

   274 #define AV_OPT_FLAG_ENCODING_PARAM  1   ///< a generic parameter which can be set by the user for muxing or encoding

   275 #define AV_OPT_FLAG_DECODING_PARAM  2   ///< a generic parameter which can be set by the user for demuxing or decoding

   276 #define AV_OPT_FLAG_METADATA        4   ///< some data extracted or inserted into the file like title, comment, ...

   277 #define AV_OPT_FLAG_AUDIO_PARAM     8

   278 #define AV_OPT_FLAG_VIDEO_PARAM     16

   279 #define AV_OPT_FLAG_SUBTITLE_PARAM  32

   280 //FIXME think about enc-audio, ... style flags

   281 

   282     /**

   283      * The logical unit to which the option belongs. Non-constant

   284      * options and corresponding named constants share the same

   285      * unit. May be NULL.

   286      */

   287     const char *unit;

   288 } AVOption;

   289 

   290 #if FF_API_FIND_OPT

   291 /**

   292  * Look for an option in obj. Look only for the options which

   293  * have the flags set as specified in mask and flags (that is,

   294  * for which it is the case that opt->flags & mask == flags).

   295  *

   296  * @param[in] obj a pointer to a struct whose first element is a

   297  * pointer to an AVClass

   298  * @param[in] name the name of the option to look for

   299  * @param[in] unit the unit of the option to look for, or any if NULL

   300  * @return a pointer to the option found, or NULL if no option

   301  * has been found

   302  *

   303  * @deprecated use av_opt_find.

   304  */

   305 attribute_deprecated

   306 const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);

   307 #endif

   308 

   309 #if FF_API_OLD_AVOPTIONS

   310 /**

   311  * Set the field of obj with the given name to value.

   312  *

   313  * @param[in] obj A struct whose first element is a pointer to an

   314  * AVClass.

   315  * @param[in] name the name of the field to set

   316  * @param[in] val The value to set. If the field is not of a string

   317  * type, then the given string is parsed.

   318  * SI postfixes and some named scalars are supported.

   319  * If the field is of a numeric type, it has to be a numeric or named

   320  * scalar. Behavior with more than one scalar and +- infix operators

   321  * is undefined.

   322  * If the field is of a flags type, it has to be a sequence of numeric

   323  * scalars or named flags separated by '+' or '-'. Prefixing a flag

   324  * with '+' causes it to be set without affecting the other flags;

   325  * similarly, '-' unsets a flag.

   326  * @param[out] o_out if non-NULL put here a pointer to the AVOption

   327  * found

   328  * @param alloc this parameter is currently ignored

   329  * @return 0 if the value has been set, or an AVERROR code in case of

   330  * error:

   331  * AVERROR_OPTION_NOT_FOUND if no matching option exists

   332  * AVERROR(ERANGE) if the value is out of range

   333  * AVERROR(EINVAL) if the value is not valid

   334  * @deprecated use av_opt_set()

   335  */

   336 attribute_deprecated

   337 int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);

   338 

   339 attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n);

   340 attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n);

   341 attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n);

   342 

   343 attribute_deprecated double av_get_double(void *obj, const char *name, const AVOption **o_out);

   344 attribute_deprecated AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);

   345 attribute_deprecated int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);

   346 attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);

   347 attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last);

   348 #endif

   349 

   350 /**

   351  * Show the obj options.

   352  *

   353  * @param req_flags requested flags for the options to show. Show only the

   354  * options for which it is opt->flags & req_flags.

   355  * @param rej_flags rejected flags for the options to show. Show only the

   356  * options for which it is !(opt->flags & req_flags).

   357  * @param av_log_obj log context to use for showing the options

   358  */

   359 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);

   360 

   361 /**

   362  * Set the values of all AVOption fields to their default values.

   363  *

   364  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)

   365  */

   366 void av_opt_set_defaults(void *s);

   367 

   368 #if FF_API_OLD_AVOPTIONS

   369 attribute_deprecated

   370 void av_opt_set_defaults2(void *s, int mask, int flags);

   371 #endif

   372 

   373 /**

   374  * Parse the key/value pairs list in opts. For each key/value pair

   375  * found, stores the value in the field in ctx that is named like the

   376  * key. ctx must be an AVClass context, storing is done using

   377  * AVOptions.

   378  *

   379  * @param key_val_sep a 0-terminated list of characters used to

   380  * separate key from value

   381  * @param pairs_sep a 0-terminated list of characters used to separate

   382  * two pairs from each other

   383  * @return the number of successfully set key/value pairs, or a negative

   384  * value corresponding to an AVERROR code in case of error:

   385  * AVERROR(EINVAL) if opts cannot be parsed,

   386  * the error code issued by av_set_string3() if a key/value pair

   387  * cannot be set

   388  */

   389 int av_set_options_string(void *ctx, const char *opts,

   390                           const char *key_val_sep, const char *pairs_sep);

   391 

   392 /**

   393  * Free all string and binary options in obj.

   394  */

   395 void av_opt_free(void *obj);

   396 

   397 /**

   398  * Check whether a particular flag is set in a flags field.

   399  *

   400  * @param field_name the name of the flag field option

   401  * @param flag_name the name of the flag to check

   402  * @return non-zero if the flag is set, zero if the flag isn't set,

   403  *         isn't of the right type, or the flags field doesn't exist.

   404  */

   405 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);

   406 

   407 /*

   408  * Set all the options from a given dictionary on an object.

   409  *

   410  * @param obj a struct whose first element is a pointer to AVClass

   411  * @param options options to process. This dictionary will be freed and replaced

   412  *                by a new one containing all options not found in obj.

   413  *                Of course this new dictionary needs to be freed by caller

   414  *                with av_dict_free().

   415  *

   416  * @return 0 on success, a negative AVERROR if some option was found in obj,

   417  *         but could not be set.

   418  *

   419  * @see av_dict_copy()

   420  */

   421 int av_opt_set_dict(void *obj, struct AVDictionary **options);

   422 

   423 /**

   424  * @defgroup opt_eval_funcs Evaluating option strings

   425  * @{

   426  * This group of functions can be used to evaluate option strings

   427  * and get numbers out of them. They do the same thing as av_opt_set(),

   428  * except the result is written into the caller-supplied pointer.

   429  *

   430  * @param obj a struct whose first element is a pointer to AVClass.

   431  * @param o an option for which the string is to be evaluated.

   432  * @param val string to be evaluated.

   433  * @param *_out value of the string will be written here.

   434  *

   435  * @return 0 on success, a negative number on failure.

   436  */

   437 int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int        *flags_out);

   438 int av_opt_eval_int   (void *obj, const AVOption *o, const char *val, int        *int_out);

   439 int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t    *int64_out);

   440 int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float      *float_out);

   441 int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double     *double_out);

   442 int av_opt_eval_q     (void *obj, const AVOption *o, const char *val, AVRational *q_out);

   443 /**

   444  * @}

   445  */

   446 

   447 #define AV_OPT_SEARCH_CHILDREN   0x0001 /**< Search in possible children of the

   448                                              given object first. */

   449 /**

   450  *  The obj passed to av_opt_find() is fake -- only a double pointer to AVClass

   451  *  instead of a required pointer to a struct containing AVClass. This is

   452  *  useful for searching for options without needing to allocate the corresponding

   453  *  object.

   454  */

   455 #define AV_OPT_SEARCH_FAKE_OBJ   0x0002

   456 

   457 /**

   458  * Look for an option in an object. Consider only options which

   459  * have all the specified flags set.

   460  *

   461  * @param[in] obj A pointer to a struct whose first element is a

   462  *                pointer to an AVClass.

   463  *                Alternatively a double pointer to an AVClass, if

   464  *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.

   465  * @param[in] name The name of the option to look for.

   466  * @param[in] unit When searching for named constants, name of the unit

   467  *                 it belongs to.

   468  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).

   469  * @param search_flags A combination of AV_OPT_SEARCH_*.

   470  *

   471  * @return A pointer to the option found, or NULL if no option

   472  *         was found.

   473  *

   474  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable

   475  * directly with av_set_string3(). Use special calls which take an options

   476  * AVDictionary (e.g. avformat_open_input()) to set options found with this

   477  * flag.

   478  */

   479 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,

   480                             int opt_flags, int search_flags);

   481 

   482 /**

   483  * Look for an option in an object. Consider only options which

   484  * have all the specified flags set.

   485  *

   486  * @param[in] obj A pointer to a struct whose first element is a

   487  *                pointer to an AVClass.

   488  *                Alternatively a double pointer to an AVClass, if

   489  *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.

   490  * @param[in] name The name of the option to look for.

   491  * @param[in] unit When searching for named constants, name of the unit

   492  *                 it belongs to.

   493  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).

   494  * @param search_flags A combination of AV_OPT_SEARCH_*.

   495  * @param[out] target_obj if non-NULL, an object to which the option belongs will be

   496  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present

   497  * in search_flags. This parameter is ignored if search_flags contain

   498  * AV_OPT_SEARCH_FAKE_OBJ.

   499  *

   500  * @return A pointer to the option found, or NULL if no option

   501  *         was found.

   502  */

   503 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,

   504                              int opt_flags, int search_flags, void **target_obj);

   505 

   506 /**

   507  * Iterate over all AVOptions belonging to obj.

   508  *

   509  * @param obj an AVOptions-enabled struct or a double pointer to an

   510  *            AVClass describing it.

   511  * @param prev result of the previous call to av_opt_next() on this object

   512  *             or NULL

   513  * @return next AVOption or NULL

   514  */

   515 const AVOption *av_opt_next(void *obj, const AVOption *prev);

   516 

   517 /**

   518  * Iterate over AVOptions-enabled children of obj.

   519  *

   520  * @param prev result of a previous call to this function or NULL

   521  * @return next AVOptions-enabled child or NULL

   522  */

   523 void *av_opt_child_next(void *obj, void *prev);

   524 

   525 /**

   526  * Iterate over potential AVOptions-enabled children of parent.

   527  *

   528  * @param prev result of a previous call to this function or NULL

   529  * @return AVClass corresponding to next potential child or NULL

   530  */

   531 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);

   532 

   533 /**

   534  * @defgroup opt_set_funcs Option setting functions

   535  * @{

   536  * Those functions set the field of obj with the given name to value.

   537  *

   538  * @param[in] obj A struct whose first element is a pointer to an AVClass.

   539  * @param[in] name the name of the field to set

   540  * @param[in] val The value to set. In case of av_opt_set() if the field is not

   541  * of a string type, then the given string is parsed.

   542  * SI postfixes and some named scalars are supported.

   543  * If the field is of a numeric type, it has to be a numeric or named

   544  * scalar. Behavior with more than one scalar and +- infix operators

   545  * is undefined.

   546  * If the field is of a flags type, it has to be a sequence of numeric

   547  * scalars or named flags separated by '+' or '-'. Prefixing a flag

   548  * with '+' causes it to be set without affecting the other flags;

   549  * similarly, '-' unsets a flag.

   550  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN

   551  * is passed here, then the option may be set on a child of obj.

   552  *

   553  * @return 0 if the value has been set, or an AVERROR code in case of

   554  * error:

   555  * AVERROR_OPTION_NOT_FOUND if no matching option exists

   556  * AVERROR(ERANGE) if the value is out of range

   557  * AVERROR(EINVAL) if the value is not valid

   558  */

   559 int av_opt_set       (void *obj, const char *name, const char *val, int search_flags);

   560 int av_opt_set_int   (void *obj, const char *name, int64_t     val, int search_flags);

   561 int av_opt_set_double(void *obj, const char *name, double      val, int search_flags);

   562 int av_opt_set_q     (void *obj, const char *name, AVRational  val, int search_flags);

   563 int av_opt_set_bin   (void *obj, const char *name, const uint8_t *val, int size, int search_flags);

   564 /**

   565  * @}

   566  */

   567 

   568 /**

   569  * @defgroup opt_get_funcs Option getting functions

   570  * @{

   571  * Those functions get a value of the option with the given name from an object.

   572  *

   573  * @param[in] obj a struct whose first element is a pointer to an AVClass.

   574  * @param[in] name name of the option to get.

   575  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN

   576  * is passed here, then the option may be found in a child of obj.

   577  * @param[out] out_val value of the option will be written here

   578  * @return 0 on success, a negative error code otherwise

   579  */

   580 /**

   581  * @note the returned string will av_malloc()ed and must be av_free()ed by the caller

   582  */

   583 int av_opt_get       (void *obj, const char *name, int search_flags, uint8_t   **out_val);

   584 int av_opt_get_int   (void *obj, const char *name, int search_flags, int64_t    *out_val);

   585 int av_opt_get_double(void *obj, const char *name, int search_flags, double     *out_val);

   586 int av_opt_get_q     (void *obj, const char *name, int search_flags, AVRational *out_val);

   587 /**

   588  * @}

   589  * @}

   590  */

   591 

   592 #endif /* AVUTIL_OPT_H */