Subversion Repositories Kolibri OS

Rev

Blame | Last modification | View Log | RSS feed

  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.  
  37. /**
  38.  * @defgroup avoptions AVOptions
  39.  * @ingroup lavu_data
  40.  * @{
  41.  * AVOptions provide a generic system to declare options on arbitrary structs
  42.  * ("objects"). An option can have a help text, a type and a range of possible
  43.  * values. Options may then be enumerated, read and written to.
  44.  *
  45.  * @section avoptions_implement Implementing AVOptions
  46.  * This section describes how to add AVOptions capabilities to a struct.
  47.  *
  48.  * All AVOptions-related information is stored in an AVClass. Therefore
  49.  * the first member of the struct should be a pointer to an AVClass describing it.
  50.  * The option field of the AVClass must be set to a NULL-terminated static array
  51.  * of AVOptions. Each AVOption must have a non-empty name, a type, a default
  52.  * value and for number-type AVOptions also a range of allowed values. It must
  53.  * also declare an offset in bytes from the start of the struct, where the field
  54.  * associated with this AVOption is located. Other fields in the AVOption struct
  55.  * should also be set when applicable, but are not required.
  56.  *
  57.  * The following example illustrates an AVOptions-enabled struct:
  58.  * @code
  59.  * typedef struct test_struct {
  60.  *     AVClass *class;
  61.  *     int      int_opt;
  62.  *     char    *str_opt;
  63.  *     uint8_t *bin_opt;
  64.  *     int      bin_len;
  65.  * } test_struct;
  66.  *
  67.  * static const AVOption test_options[] = {
  68.  *   { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
  69.  *     AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
  70.  *   { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
  71.  *     AV_OPT_TYPE_STRING },
  72.  *   { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
  73.  *     AV_OPT_TYPE_BINARY },
  74.  *   { NULL },
  75.  * };
  76.  *
  77.  * static const AVClass test_class = {
  78.  *     .class_name = "test class",
  79.  *     .item_name  = av_default_item_name,
  80.  *     .option     = test_options,
  81.  *     .version    = LIBAVUTIL_VERSION_INT,
  82.  * };
  83.  * @endcode
  84.  *
  85.  * Next, when allocating your struct, you must ensure that the AVClass pointer
  86.  * is set to the correct value. Then, av_opt_set_defaults() can be called to
  87.  * initialize defaults. After that the struct is ready to be used with the
  88.  * AVOptions API.
  89.  *
  90.  * When cleaning up, you may use the av_opt_free() function to automatically
  91.  * free all the allocated string and binary options.
  92.  *
  93.  * Continuing with the above example:
  94.  *
  95.  * @code
  96.  * test_struct *alloc_test_struct(void)
  97.  * {
  98.  *     test_struct *ret = av_malloc(sizeof(*ret));
  99.  *     ret->class = &test_class;
  100.  *     av_opt_set_defaults(ret);
  101.  *     return ret;
  102.  * }
  103.  * void free_test_struct(test_struct **foo)
  104.  * {
  105.  *     av_opt_free(*foo);
  106.  *     av_freep(foo);
  107.  * }
  108.  * @endcode
  109.  *
  110.  * @subsection avoptions_implement_nesting Nesting
  111.  *      It may happen that an AVOptions-enabled struct contains another
  112.  *      AVOptions-enabled struct as a member (e.g. AVCodecContext in
  113.  *      libavcodec exports generic options, while its priv_data field exports
  114.  *      codec-specific options). In such a case, it is possible to set up the
  115.  *      parent struct to export a child's options. To do that, simply
  116.  *      implement AVClass.child_next() and AVClass.child_class_next() in the
  117.  *      parent struct's AVClass.
  118.  *      Assuming that the test_struct from above now also contains a
  119.  *      child_struct field:
  120.  *
  121.  *      @code
  122.  *      typedef struct child_struct {
  123.  *          AVClass *class;
  124.  *          int flags_opt;
  125.  *      } child_struct;
  126.  *      static const AVOption child_opts[] = {
  127.  *          { "test_flags", "This is a test option of flags type.",
  128.  *            offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
  129.  *          { NULL },
  130.  *      };
  131.  *      static const AVClass child_class = {
  132.  *          .class_name = "child class",
  133.  *          .item_name  = av_default_item_name,
  134.  *          .option     = child_opts,
  135.  *          .version    = LIBAVUTIL_VERSION_INT,
  136.  *      };
  137.  *
  138.  *      void *child_next(void *obj, void *prev)
  139.  *      {
  140.  *          test_struct *t = obj;
  141.  *          if (!prev && t->child_struct)
  142.  *              return t->child_struct;
  143.  *          return NULL
  144.  *      }
  145.  *      const AVClass child_class_next(const AVClass *prev)
  146.  *      {
  147.  *          return prev ? NULL : &child_class;
  148.  *      }
  149.  *      @endcode
  150.  *      Putting child_next() and child_class_next() as defined above into
  151.  *      test_class will now make child_struct's options accessible through
  152.  *      test_struct (again, proper setup as described above needs to be done on
  153.  *      child_struct right after it is created).
  154.  *
  155.  *      From the above example it might not be clear why both child_next()
  156.  *      and child_class_next() are needed. The distinction is that child_next()
  157.  *      iterates over actually existing objects, while child_class_next()
  158.  *      iterates over all possible child classes. E.g. if an AVCodecContext
  159.  *      was initialized to use a codec which has private options, then its
  160.  *      child_next() will return AVCodecContext.priv_data and finish
  161.  *      iterating. OTOH child_class_next() on AVCodecContext.av_class will
  162.  *      iterate over all available codecs with private options.
  163.  *
  164.  * @subsection avoptions_implement_named_constants Named constants
  165.  *      It is possible to create named constants for options. Simply set the unit
  166.  *      field of the option the constants should apply to a string and
  167.  *      create the constants themselves as options of type AV_OPT_TYPE_CONST
  168.  *      with their unit field set to the same string.
  169.  *      Their default_val field should contain the value of the named
  170.  *      constant.
  171.  *      For example, to add some named constants for the test_flags option
  172.  *      above, put the following into the child_opts array:
  173.  *      @code
  174.  *      { "test_flags", "This is a test option of flags type.",
  175.  *        offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
  176.  *      { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
  177.  *      @endcode
  178.  *
  179.  * @section avoptions_use Using AVOptions
  180.  * This section deals with accessing options in an AVOptions-enabled struct.
  181.  * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
  182.  * AVFormatContext in libavformat.
  183.  *
  184.  * @subsection avoptions_use_examine Examining AVOptions
  185.  * The basic functions for examining options are av_opt_next(), which iterates
  186.  * over all options defined for one object, and av_opt_find(), which searches
  187.  * for an option with the given name.
  188.  *
  189.  * The situation is more complicated with nesting. An AVOptions-enabled struct
  190.  * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
  191.  * to av_opt_find() will make the function search children recursively.
  192.  *
  193.  * For enumerating there are basically two cases. The first is when you want to
  194.  * get all options that may potentially exist on the struct and its children
  195.  * (e.g.  when constructing documentation). In that case you should call
  196.  * av_opt_child_class_next() recursively on the parent struct's AVClass.  The
  197.  * second case is when you have an already initialized struct with all its
  198.  * children and you want to get all options that can be actually written or read
  199.  * from it. In that case you should call av_opt_child_next() recursively (and
  200.  * av_opt_next() on each result).
  201.  *
  202.  * @subsection avoptions_use_get_set Reading and writing AVOptions
  203.  * When setting options, you often have a string read directly from the
  204.  * user. In such a case, simply passing it to av_opt_set() is enough. For
  205.  * non-string type options, av_opt_set() will parse the string according to the
  206.  * option type.
  207.  *
  208.  * Similarly av_opt_get() will read any option type and convert it to a string
  209.  * which will be returned. Do not forget that the string is allocated, so you
  210.  * have to free it with av_free().
  211.  *
  212.  * In some cases it may be more convenient to put all options into an
  213.  * AVDictionary and call av_opt_set_dict() on it. A specific case of this
  214.  * are the format/codec open functions in lavf/lavc which take a dictionary
  215.  * filled with option as a parameter. This allows to set some options
  216.  * that cannot be set otherwise, since e.g. the input file format is not known
  217.  * before the file is actually opened.
  218.  */
  219.  
  220. enum AVOptionType{
  221.     AV_OPT_TYPE_FLAGS,
  222.     AV_OPT_TYPE_INT,
  223.     AV_OPT_TYPE_INT64,
  224.     AV_OPT_TYPE_DOUBLE,
  225.     AV_OPT_TYPE_FLOAT,
  226.     AV_OPT_TYPE_STRING,
  227.     AV_OPT_TYPE_RATIONAL,
  228.     AV_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length
  229.     AV_OPT_TYPE_CONST = 128,
  230.     AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers
  231.     AV_OPT_TYPE_PIXEL_FMT  = MKBETAG('P','F','M','T'),
  232.     AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'),
  233.     AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational
  234.     AV_OPT_TYPE_DURATION   = MKBETAG('D','U','R',' '),
  235.     AV_OPT_TYPE_COLOR      = MKBETAG('C','O','L','R'),
  236.     AV_OPT_TYPE_CHANNEL_LAYOUT = MKBETAG('C','H','L','A'),
  237. #if FF_API_OLD_AVOPTIONS
  238.     FF_OPT_TYPE_FLAGS = 0,
  239.     FF_OPT_TYPE_INT,
  240.     FF_OPT_TYPE_INT64,
  241.     FF_OPT_TYPE_DOUBLE,
  242.     FF_OPT_TYPE_FLOAT,
  243.     FF_OPT_TYPE_STRING,
  244.     FF_OPT_TYPE_RATIONAL,
  245.     FF_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length
  246.     FF_OPT_TYPE_CONST=128,
  247. #endif
  248. };
  249.  
  250. /**
  251.  * AVOption
  252.  */
  253. typedef struct AVOption {
  254.     const char *name;
  255.  
  256.     /**
  257.      * short English help text
  258.      * @todo What about other languages?
  259.      */
  260.     const char *help;
  261.  
  262.     /**
  263.      * The offset relative to the context structure where the option
  264.      * value is stored. It should be 0 for named constants.
  265.      */
  266.     int offset;
  267.     enum AVOptionType type;
  268.  
  269.     /**
  270.      * the default value for scalar options
  271.      */
  272.     union {
  273.         int64_t i64;
  274.         double dbl;
  275.         const char *str;
  276.         /* TODO those are unused now */
  277.         AVRational q;
  278.     } default_val;
  279.     double min;                 ///< minimum valid value for the option
  280.     double max;                 ///< maximum valid value for the option
  281.  
  282.     int flags;
  283. #define AV_OPT_FLAG_ENCODING_PARAM  1   ///< a generic parameter which can be set by the user for muxing or encoding
  284. #define AV_OPT_FLAG_DECODING_PARAM  2   ///< a generic parameter which can be set by the user for demuxing or decoding
  285. #define AV_OPT_FLAG_METADATA        4   ///< some data extracted or inserted into the file like title, comment, ...
  286. #define AV_OPT_FLAG_AUDIO_PARAM     8
  287. #define AV_OPT_FLAG_VIDEO_PARAM     16
  288. #define AV_OPT_FLAG_SUBTITLE_PARAM  32
  289. #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
  290. //FIXME think about enc-audio, ... style flags
  291.  
  292.     /**
  293.      * The logical unit to which the option belongs. Non-constant
  294.      * options and corresponding named constants share the same
  295.      * unit. May be NULL.
  296.      */
  297.     const char *unit;
  298. } AVOption;
  299.  
  300. /**
  301.  * A single allowed range of values, or a single allowed value.
  302.  */
  303. typedef struct AVOptionRange {
  304.     const char *str;
  305.     double value_min, value_max;             ///< For string ranges this represents the min/max length, for dimensions this represents the min/max pixel count
  306.     double component_min, component_max;     ///< For string this represents the unicode range for chars, 0-127 limits to ASCII
  307.     int is_range;                            ///< if set to 1 the struct encodes a range, if set to 0 a single value
  308. } AVOptionRange;
  309.  
  310. /**
  311.  * List of AVOptionRange structs
  312.  */
  313. typedef struct AVOptionRanges {
  314.     AVOptionRange **range;
  315.     int nb_ranges;
  316. } AVOptionRanges;
  317.  
  318.  
  319. #if FF_API_FIND_OPT
  320. /**
  321.  * Look for an option in obj. Look only for the options which
  322.  * have the flags set as specified in mask and flags (that is,
  323.  * for which it is the case that (opt->flags & mask) == flags).
  324.  *
  325.  * @param[in] obj a pointer to a struct whose first element is a
  326.  * pointer to an AVClass
  327.  * @param[in] name the name of the option to look for
  328.  * @param[in] unit the unit of the option to look for, or any if NULL
  329.  * @return a pointer to the option found, or NULL if no option
  330.  * has been found
  331.  *
  332.  * @deprecated use av_opt_find.
  333.  */
  334. attribute_deprecated
  335. const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
  336. #endif
  337.  
  338. #if FF_API_OLD_AVOPTIONS
  339. /**
  340.  * Set the field of obj with the given name to value.
  341.  *
  342.  * @param[in] obj A struct whose first element is a pointer to an
  343.  * AVClass.
  344.  * @param[in] name the name of the field to set
  345.  * @param[in] val The value to set. If the field is not of a string
  346.  * type, then the given string is parsed.
  347.  * SI postfixes and some named scalars are supported.
  348.  * If the field is of a numeric type, it has to be a numeric or named
  349.  * scalar. Behavior with more than one scalar and +- infix operators
  350.  * is undefined.
  351.  * If the field is of a flags type, it has to be a sequence of numeric
  352.  * scalars or named flags separated by '+' or '-'. Prefixing a flag
  353.  * with '+' causes it to be set without affecting the other flags;
  354.  * similarly, '-' unsets a flag.
  355.  * @param[out] o_out if non-NULL put here a pointer to the AVOption
  356.  * found
  357.  * @param alloc this parameter is currently ignored
  358.  * @return 0 if the value has been set, or an AVERROR code in case of
  359.  * error:
  360.  * AVERROR_OPTION_NOT_FOUND if no matching option exists
  361.  * AVERROR(ERANGE) if the value is out of range
  362.  * AVERROR(EINVAL) if the value is not valid
  363.  * @deprecated use av_opt_set()
  364.  */
  365. attribute_deprecated
  366. int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
  367.  
  368. attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n);
  369. attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n);
  370. attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n);
  371.  
  372. double av_get_double(void *obj, const char *name, const AVOption **o_out);
  373. AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
  374. int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
  375. attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
  376. attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last);
  377. #endif
  378.  
  379. /**
  380.  * Show the obj options.
  381.  *
  382.  * @param req_flags requested flags for the options to show. Show only the
  383.  * options for which it is opt->flags & req_flags.
  384.  * @param rej_flags rejected flags for the options to show. Show only the
  385.  * options for which it is !(opt->flags & req_flags).
  386.  * @param av_log_obj log context to use for showing the options
  387.  */
  388. int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
  389.  
  390. /**
  391.  * Set the values of all AVOption fields to their default values.
  392.  *
  393.  * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
  394.  */
  395. void av_opt_set_defaults(void *s);
  396.  
  397. #if FF_API_OLD_AVOPTIONS
  398. attribute_deprecated
  399. void av_opt_set_defaults2(void *s, int mask, int flags);
  400. #endif
  401.  
  402. /**
  403.  * Parse the key/value pairs list in opts. For each key/value pair
  404.  * found, stores the value in the field in ctx that is named like the
  405.  * key. ctx must be an AVClass context, storing is done using
  406.  * AVOptions.
  407.  *
  408.  * @param opts options string to parse, may be NULL
  409.  * @param key_val_sep a 0-terminated list of characters used to
  410.  * separate key from value
  411.  * @param pairs_sep a 0-terminated list of characters used to separate
  412.  * two pairs from each other
  413.  * @return the number of successfully set key/value pairs, or a negative
  414.  * value corresponding to an AVERROR code in case of error:
  415.  * AVERROR(EINVAL) if opts cannot be parsed,
  416.  * the error code issued by av_set_string3() if a key/value pair
  417.  * cannot be set
  418.  */
  419. int av_set_options_string(void *ctx, const char *opts,
  420.                           const char *key_val_sep, const char *pairs_sep);
  421.  
  422. /**
  423.  * Parse the key-value pairs list in opts. For each key=value pair found,
  424.  * set the value of the corresponding option in ctx.
  425.  *
  426.  * @param ctx          the AVClass object to set options on
  427.  * @param opts         the options string, key-value pairs separated by a
  428.  *                     delimiter
  429.  * @param shorthand    a NULL-terminated array of options names for shorthand
  430.  *                     notation: if the first field in opts has no key part,
  431.  *                     the key is taken from the first element of shorthand;
  432.  *                     then again for the second, etc., until either opts is
  433.  *                     finished, shorthand is finished or a named option is
  434.  *                     found; after that, all options must be named
  435.  * @param key_val_sep  a 0-terminated list of characters used to separate
  436.  *                     key from value, for example '='
  437.  * @param pairs_sep    a 0-terminated list of characters used to separate
  438.  *                     two pairs from each other, for example ':' or ','
  439.  * @return  the number of successfully set key=value pairs, or a negative
  440.  *          value corresponding to an AVERROR code in case of error:
  441.  *          AVERROR(EINVAL) if opts cannot be parsed,
  442.  *          the error code issued by av_set_string3() if a key/value pair
  443.  *          cannot be set
  444.  *
  445.  * Options names must use only the following characters: a-z A-Z 0-9 - . / _
  446.  * Separators must use characters distinct from option names and from each
  447.  * other.
  448.  */
  449. int av_opt_set_from_string(void *ctx, const char *opts,
  450.                            const char *const *shorthand,
  451.                            const char *key_val_sep, const char *pairs_sep);
  452. /**
  453.  * Free all string and binary options in obj.
  454.  */
  455. void av_opt_free(void *obj);
  456.  
  457. /**
  458.  * Check whether a particular flag is set in a flags field.
  459.  *
  460.  * @param field_name the name of the flag field option
  461.  * @param flag_name the name of the flag to check
  462.  * @return non-zero if the flag is set, zero if the flag isn't set,
  463.  *         isn't of the right type, or the flags field doesn't exist.
  464.  */
  465. int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
  466.  
  467. /**
  468.  * Set all the options from a given dictionary on an object.
  469.  *
  470.  * @param obj a struct whose first element is a pointer to AVClass
  471.  * @param options options to process. This dictionary will be freed and replaced
  472.  *                by a new one containing all options not found in obj.
  473.  *                Of course this new dictionary needs to be freed by caller
  474.  *                with av_dict_free().
  475.  *
  476.  * @return 0 on success, a negative AVERROR if some option was found in obj,
  477.  *         but could not be set.
  478.  *
  479.  * @see av_dict_copy()
  480.  */
  481. int av_opt_set_dict(void *obj, struct AVDictionary **options);
  482.  
  483. /**
  484.  * Extract a key-value pair from the beginning of a string.
  485.  *
  486.  * @param ropts        pointer to the options string, will be updated to
  487.  *                     point to the rest of the string (one of the pairs_sep
  488.  *                     or the final NUL)
  489.  * @param key_val_sep  a 0-terminated list of characters used to separate
  490.  *                     key from value, for example '='
  491.  * @param pairs_sep    a 0-terminated list of characters used to separate
  492.  *                     two pairs from each other, for example ':' or ','
  493.  * @param flags        flags; see the AV_OPT_FLAG_* values below
  494.  * @param rkey         parsed key; must be freed using av_free()
  495.  * @param rval         parsed value; must be freed using av_free()
  496.  *
  497.  * @return  >=0 for success, or a negative value corresponding to an
  498.  *          AVERROR code in case of error; in particular:
  499.  *          AVERROR(EINVAL) if no key is present
  500.  *
  501.  */
  502. int av_opt_get_key_value(const char **ropts,
  503.                          const char *key_val_sep, const char *pairs_sep,
  504.                          unsigned flags,
  505.                          char **rkey, char **rval);
  506.  
  507. enum {
  508.  
  509.     /**
  510.      * Accept to parse a value without a key; the key will then be returned
  511.      * as NULL.
  512.      */
  513.     AV_OPT_FLAG_IMPLICIT_KEY = 1,
  514. };
  515.  
  516. /**
  517.  * @defgroup opt_eval_funcs Evaluating option strings
  518.  * @{
  519.  * This group of functions can be used to evaluate option strings
  520.  * and get numbers out of them. They do the same thing as av_opt_set(),
  521.  * except the result is written into the caller-supplied pointer.
  522.  *
  523.  * @param obj a struct whose first element is a pointer to AVClass.
  524.  * @param o an option for which the string is to be evaluated.
  525.  * @param val string to be evaluated.
  526.  * @param *_out value of the string will be written here.
  527.  *
  528.  * @return 0 on success, a negative number on failure.
  529.  */
  530. int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int        *flags_out);
  531. int av_opt_eval_int   (void *obj, const AVOption *o, const char *val, int        *int_out);
  532. int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t    *int64_out);
  533. int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float      *float_out);
  534. int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double     *double_out);
  535. int av_opt_eval_q     (void *obj, const AVOption *o, const char *val, AVRational *q_out);
  536. /**
  537.  * @}
  538.  */
  539.  
  540. #define AV_OPT_SEARCH_CHILDREN   0x0001 /**< Search in possible children of the
  541.                                              given object first. */
  542. /**
  543.  *  The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
  544.  *  instead of a required pointer to a struct containing AVClass. This is
  545.  *  useful for searching for options without needing to allocate the corresponding
  546.  *  object.
  547.  */
  548. #define AV_OPT_SEARCH_FAKE_OBJ   0x0002
  549.  
  550. /**
  551.  * Look for an option in an object. Consider only options which
  552.  * have all the specified flags set.
  553.  *
  554.  * @param[in] obj A pointer to a struct whose first element is a
  555.  *                pointer to an AVClass.
  556.  *                Alternatively a double pointer to an AVClass, if
  557.  *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.
  558.  * @param[in] name The name of the option to look for.
  559.  * @param[in] unit When searching for named constants, name of the unit
  560.  *                 it belongs to.
  561.  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
  562.  * @param search_flags A combination of AV_OPT_SEARCH_*.
  563.  *
  564.  * @return A pointer to the option found, or NULL if no option
  565.  *         was found.
  566.  *
  567.  * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
  568.  * directly with av_set_string3(). Use special calls which take an options
  569.  * AVDictionary (e.g. avformat_open_input()) to set options found with this
  570.  * flag.
  571.  */
  572. const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
  573.                             int opt_flags, int search_flags);
  574.  
  575. /**
  576.  * Look for an option in an object. Consider only options which
  577.  * have all the specified flags set.
  578.  *
  579.  * @param[in] obj A pointer to a struct whose first element is a
  580.  *                pointer to an AVClass.
  581.  *                Alternatively a double pointer to an AVClass, if
  582.  *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.
  583.  * @param[in] name The name of the option to look for.
  584.  * @param[in] unit When searching for named constants, name of the unit
  585.  *                 it belongs to.
  586.  * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
  587.  * @param search_flags A combination of AV_OPT_SEARCH_*.
  588.  * @param[out] target_obj if non-NULL, an object to which the option belongs will be
  589.  * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
  590.  * in search_flags. This parameter is ignored if search_flags contain
  591.  * AV_OPT_SEARCH_FAKE_OBJ.
  592.  *
  593.  * @return A pointer to the option found, or NULL if no option
  594.  *         was found.
  595.  */
  596. const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
  597.                              int opt_flags, int search_flags, void **target_obj);
  598.  
  599. /**
  600.  * Iterate over all AVOptions belonging to obj.
  601.  *
  602.  * @param obj an AVOptions-enabled struct or a double pointer to an
  603.  *            AVClass describing it.
  604.  * @param prev result of the previous call to av_opt_next() on this object
  605.  *             or NULL
  606.  * @return next AVOption or NULL
  607.  */
  608. const AVOption *av_opt_next(void *obj, const AVOption *prev);
  609.  
  610. /**
  611.  * Iterate over AVOptions-enabled children of obj.
  612.  *
  613.  * @param prev result of a previous call to this function or NULL
  614.  * @return next AVOptions-enabled child or NULL
  615.  */
  616. void *av_opt_child_next(void *obj, void *prev);
  617.  
  618. /**
  619.  * Iterate over potential AVOptions-enabled children of parent.
  620.  *
  621.  * @param prev result of a previous call to this function or NULL
  622.  * @return AVClass corresponding to next potential child or NULL
  623.  */
  624. const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
  625.  
  626. /**
  627.  * @defgroup opt_set_funcs Option setting functions
  628.  * @{
  629.  * Those functions set the field of obj with the given name to value.
  630.  *
  631.  * @param[in] obj A struct whose first element is a pointer to an AVClass.
  632.  * @param[in] name the name of the field to set
  633.  * @param[in] val The value to set. In case of av_opt_set() if the field is not
  634.  * of a string type, then the given string is parsed.
  635.  * SI postfixes and some named scalars are supported.
  636.  * If the field is of a numeric type, it has to be a numeric or named
  637.  * scalar. Behavior with more than one scalar and +- infix operators
  638.  * is undefined.
  639.  * If the field is of a flags type, it has to be a sequence of numeric
  640.  * scalars or named flags separated by '+' or '-'. Prefixing a flag
  641.  * with '+' causes it to be set without affecting the other flags;
  642.  * similarly, '-' unsets a flag.
  643.  * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
  644.  * is passed here, then the option may be set on a child of obj.
  645.  *
  646.  * @return 0 if the value has been set, or an AVERROR code in case of
  647.  * error:
  648.  * AVERROR_OPTION_NOT_FOUND if no matching option exists
  649.  * AVERROR(ERANGE) if the value is out of range
  650.  * AVERROR(EINVAL) if the value is not valid
  651.  */
  652. int av_opt_set       (void *obj, const char *name, const char *val, int search_flags);
  653. int av_opt_set_int   (void *obj, const char *name, int64_t     val, int search_flags);
  654. int av_opt_set_double(void *obj, const char *name, double      val, int search_flags);
  655. int av_opt_set_q     (void *obj, const char *name, AVRational  val, int search_flags);
  656. int av_opt_set_bin   (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
  657. int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
  658. int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
  659. int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
  660. int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
  661. int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
  662.  
  663. /**
  664.  * Set a binary option to an integer list.
  665.  *
  666.  * @param obj    AVClass object to set options on
  667.  * @param name   name of the binary option
  668.  * @param val    pointer to an integer list (must have the correct type with
  669.  *               regard to the contents of the list)
  670.  * @param term   list terminator (usually 0 or -1)
  671.  * @param flags  search flags
  672.  */
  673. #define av_opt_set_int_list(obj, name, val, term, flags) \
  674.     (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
  675.      AVERROR(EINVAL) : \
  676.      av_opt_set_bin(obj, name, (const uint8_t *)(val), \
  677.                     av_int_list_length(val, term) * sizeof(*(val)), flags))
  678. /**
  679.  * @}
  680.  */
  681.  
  682. /**
  683.  * @defgroup opt_get_funcs Option getting functions
  684.  * @{
  685.  * Those functions get a value of the option with the given name from an object.
  686.  *
  687.  * @param[in] obj a struct whose first element is a pointer to an AVClass.
  688.  * @param[in] name name of the option to get.
  689.  * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
  690.  * is passed here, then the option may be found in a child of obj.
  691.  * @param[out] out_val value of the option will be written here
  692.  * @return >=0 on success, a negative error code otherwise
  693.  */
  694. /**
  695.  * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
  696.  */
  697. int av_opt_get       (void *obj, const char *name, int search_flags, uint8_t   **out_val);
  698. int av_opt_get_int   (void *obj, const char *name, int search_flags, int64_t    *out_val);
  699. int av_opt_get_double(void *obj, const char *name, int search_flags, double     *out_val);
  700. int av_opt_get_q     (void *obj, const char *name, int search_flags, AVRational *out_val);
  701. int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
  702. int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
  703. int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
  704. int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
  705. int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
  706. /**
  707.  * @}
  708.  */
  709. /**
  710.  * Gets a pointer to the requested field in a struct.
  711.  * This function allows accessing a struct even when its fields are moved or
  712.  * renamed since the application making the access has been compiled,
  713.  *
  714.  * @returns a pointer to the field, it can be cast to the correct type and read
  715.  *          or written to.
  716.  */
  717. void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
  718.  
  719. /**
  720.  * Free an AVOptionRanges struct and set it to NULL.
  721.  */
  722. void av_opt_freep_ranges(AVOptionRanges **ranges);
  723.  
  724. /**
  725.  * Get a list of allowed ranges for the given option.
  726.  *
  727.  * The returned list may depend on other fields in obj like for example profile.
  728.  *
  729.  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
  730.  *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
  731.  *
  732.  * The result must be freed with av_opt_freep_ranges.
  733.  *
  734.  * @return >= 0 on success, a negative errro code otherwise
  735.  */
  736. int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
  737.  
  738. /**
  739.  * Get a default list of allowed ranges for the given option.
  740.  *
  741.  * This list is constructed without using the AVClass.query_ranges() callback
  742.  * and can be used as fallback from within the callback.
  743.  *
  744.  * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
  745.  *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
  746.  *
  747.  * The result must be freed with av_opt_free_ranges.
  748.  *
  749.  * @return >= 0 on success, a negative errro code otherwise
  750.  */
  751. int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
  752.  
  753. /**
  754.  * @}
  755.  */
  756.  
  757. #endif /* AVUTIL_OPT_H */
  758.