Delphi-OpenCV/include/ffmpeg/libavutil/opt.pas

unit opt;

{$include ffmpeg.inc}

interface

uses
  ctypes, rational;

/// *
// * AVOptions
// * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
// *
// * This file is part of FFmpeg.
// *
// * FFmpeg is free software; you can redistribute it and/or
// * modify it under the terms of the GNU Lesser General Public
// * License as published by the Free Software Foundation; either
// * version 2.1 of the License, or (at your option) any later version.
// *
// * FFmpeg is distributed in the hope that it will be useful,
// * but WITHOUT ANY WARRANTY; without even the implied warranty of
// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// * Lesser General Public License for more details.
// *
// * You should have received a copy of the GNU Lesser General Public
// * License along with FFmpeg; if not, write to the Free Software
// * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
// */
//
/// **
// * @file
// * AVOptions
// */
//
// #include "rational.h"
// #include "avutil.h"
// #include "dict.h"
// #include "log.h"
// #include "pixfmt.h"
// #include "samplefmt.h"
//
/// **
// * @defgroup avoptions AVOptions
// * @ingroup lavu_data
// * @{
// * AVOptions provide a generic system to declare options on arbitrary structs
// * ("objects"). An option can have a help text, a type and a range of possible
// * values. Options may then be enumerated, read and written to.
// *
// * @section avoptions_implement Implementing AVOptions
// * This section describes how to add AVOptions capabilities to a struct.
// *
// * All AVOptions-related information is stored in an AVClass. Therefore
// * the first member of the struct should be a pointer to an AVClass describing it.
// * The option field of the AVClass must be set to a NULL-terminated static array
// * of AVOptions. Each AVOption must have a non-empty name, a type, a default
// * value and for number-type AVOptions also a range of allowed values. It must
// * also declare an offset in bytes from the start of the struct, where the field
// * associated with this AVOption is located. Other fields in the AVOption struct
// * should also be set when applicable, but are not required.
// *
// * The following example illustrates an AVOptions-enabled struct:
// * @code
// * typedef struct test_struct {
// *     AVClass *class;
// *     int      int_opt;
// *     char    *str_opt;
// *     uint8_t *bin_opt;
// *     int      bin_len;
// * } test_struct;
// *
// * static const AVOption test_options[] = {
// *   { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
// *     AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
// *   { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
// *     AV_OPT_TYPE_STRING },
// *   { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),
// *     AV_OPT_TYPE_BINARY },
// *   { NULL },
// * };
// *
// * static const AVClass test_class = {
// *     .class_name = "test class",
// *     .item_name  = av_default_item_name,
// *     .option     = test_options,
// *     .version    = LIBAVUTIL_VERSION_INT,
// * };
// * @endcode
// *
// * Next, when allocating your struct, you must ensure that the AVClass pointer
// * is set to the correct value. Then, av_opt_set_defaults() can be called to
// * initialize defaults. After that the struct is ready to be used with the
// * AVOptions API.
// *
// * When cleaning up, you may use the av_opt_free() function to automatically
// * free all the allocated string and binary options.
// *
// * Continuing with the above example:
// *
// * @code
// * test_struct *alloc_test_struct(void)
// * {
// *     test_struct *ret = av_malloc(sizeof(*ret));
// *     ret->class = &test_class;
// *     av_opt_set_defaults(ret);
// *     return ret;
// * }
// * void free_test_struct(test_struct **foo)
// * {
// *     av_opt_free(*foo);
// *     av_freep(foo);
// * }
// * @endcode
// *
// * @subsection avoptions_implement_nesting Nesting
// *      It may happen that an AVOptions-enabled struct contains another
// *      AVOptions-enabled struct as a member (e.g. AVCodecContext in
// *      libavcodec exports generic options, while its priv_data field exports
// *      codec-specific options). In such a case, it is possible to set up the
// *      parent struct to export a child's options. To do that, simply
// *      implement AVClass.child_next() and AVClass.child_class_next() in the
// *      parent struct's AVClass.
// *      Assuming that the test_struct from above now also contains a
// *      child_struct field:
// *
// *      @code
// *      typedef struct child_struct {
// *          AVClass *class;
// *          int flags_opt;
// *      } child_struct;
// *      static const AVOption child_opts[] = {
// *          { "test_flags", "This is a test option of flags type.",
// *            offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },
// *          { NULL },
// *      };
// *      static const AVClass child_class = {
// *          .class_name = "child class",
// *          .item_name  = av_default_item_name,
// *          .option     = child_opts,
// *          .version    = LIBAVUTIL_VERSION_INT,
// *      };
// *
// *      void *child_next(void *obj, void *prev)
// *      {
// *          test_struct *t = obj;
// *          if (!prev && t->child_struct)
// *              return t->child_struct;
// *          return NULL
// *      }
// *      const AVClass child_class_next(const AVClass *prev)
// *      {
// *          return prev ? NULL : &child_class;
// *      }
// *      @endcode
// *      Putting child_next() and child_class_next() as defined above into
// *      test_class will now make child_struct's options accessible through
// *      test_struct (again, proper setup as described above needs to be done on
// *      child_struct right after it is created).
// *
// *      From the above example it might not be clear why both child_next()
// *      and child_class_next() are needed. The distinction is that child_next()
// *      iterates over actually existing objects, while child_class_next()
// *      iterates over all possible child classes. E.g. if an AVCodecContext
// *      was initialized to use a codec which has private options, then its
// *      child_next() will return AVCodecContext.priv_data and finish
// *      iterating. OTOH child_class_next() on AVCodecContext.av_class will
// *      iterate over all available codecs with private options.
// *
// * @subsection avoptions_implement_named_constants Named constants
// *      It is possible to create named constants for options. Simply set the unit
// *      field of the option the constants should apply to a string and
// *      create the constants themselves as options of type AV_OPT_TYPE_CONST
// *      with their unit field set to the same string.
// *      Their default_val field should contain the value of the named
// *      constant.
// *      For example, to add some named constants for the test_flags option
// *      above, put the following into the child_opts array:
// *      @code
// *      { "test_flags", "This is a test option of flags type.",
// *        offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },
// *      { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },
// *      @endcode
// *
// * @section avoptions_use Using AVOptions
// * This section deals with accessing options in an AVOptions-enabled struct.
// * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or
// * AVFormatContext in libavformat.
// *
// * @subsection avoptions_use_examine Examining AVOptions
// * The basic functions for examining options are av_opt_next(), which iterates
// * over all options defined for one object, and av_opt_find(), which searches
// * for an option with the given name.
// *
// * The situation is more complicated with nesting. An AVOptions-enabled struct
// * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag
// * to av_opt_find() will make the function search children recursively.
// *
// * For enumerating there are basically two cases. The first is when you want to
// * get all options that may potentially exist on the struct and its children
// * (e.g.  when constructing documentation). In that case you should call
// * av_opt_child_class_next() recursively on the parent struct's AVClass.  The
// * second case is when you have an already initialized struct with all its
// * children and you want to get all options that can be actually written or read
// * from it. In that case you should call av_opt_child_next() recursively (and
// * av_opt_next() on each result).
// *
// * @subsection avoptions_use_get_set Reading and writing AVOptions
// * When setting options, you often have a string read directly from the
// * user. In such a case, simply passing it to av_opt_set() is enough. For
// * non-string type options, av_opt_set() will parse the string according to the
// * option type.
// *
// * Similarly av_opt_get() will read any option type and convert it to a string
// * which will be returned. Do not forget that the string is allocated, so you
// * have to free it with av_free().
// *
// * In some cases it may be more convenient to put all options into an
// * AVDictionary and call av_opt_set_dict() on it. A specific case of this
// * are the format/codec open functions in lavf/lavc which take a dictionary
// * filled with option as a parameter. This allows to set some options
// * that cannot be set otherwise, since e.g. the input file format is not known
// * before the file is actually opened.
// */
Type
  TAVOptionType = (
    { } AV_OPT_TYPE_FLAGS,
    { } AV_OPT_TYPE_INT,
    { } AV_OPT_TYPE_INT64,
    { } AV_OPT_TYPE_DOUBLE,
    { } AV_OPT_TYPE_FLOAT,
    { } AV_OPT_TYPE_STRING,
    { } AV_OPT_TYPE_RATIONAL,
    { } AV_OPT_TYPE_BINARY,
    // < offset must point to a pointer immediately followed by an int for the length
    { } AV_OPT_TYPE_CONST = 128,
    { } AV_OPT_TYPE_IMAGE_SIZE = $53495A45, // MKBETAG('S', 'I', 'Z', 'E'),  // < offset must point to two consecutive integers
    { } AV_OPT_TYPE_PIXEL_FMT = $50464D54, // MKBETAG('P', 'F', 'M', 'T'),
    { } AV_OPT_TYPE_SAMPLE_FMT = $53464D54, // MKBETAG('S', 'F', 'M', 'T'),
    { } AV_OPT_TYPE_VIDEO_RATE = $56524154, // MKBETAG('V', 'R', 'A', 'T'),    // < offset must point to AVRational
    { } AV_OPT_TYPE_DURATION = $44555220, // MKBETAG('D', 'U', 'R', ' '),
    { } AV_OPT_TYPE_COLOR = $434F4C52, // MKBETAG('C', 'O', 'L', 'R'),
    { } AV_OPT_TYPE_CHANNEL_LAYOUT = $43484C41 // MKBETAG('C', 'H', 'L', 'A'),
{$IFDEF FF_API_OLD_AVOPTIONS}
    ,
    { } FF_OPT_TYPE_FLAGS = 0,
    { } FF_OPT_TYPE_INT,
    { } FF_OPT_TYPE_INT64,
    { } FF_OPT_TYPE_DOUBLE,
    { } FF_OPT_TYPE_FLOAT,
    { } FF_OPT_TYPE_STRING,
    { } FF_OPT_TYPE_RATIONAL,
    { } FF_OPT_TYPE_BINARY, // < offset must point to a pointer immediately followed by an int for the length
    { } FF_OPT_TYPE_CONST = 128
{$ENDIF}
    );

Const
  AV_OPT_FLAG_ENCODING_PARAM = 1;
  /// < a generic parameter which can be set by the user for muxing or encoding
  AV_OPT_FLAG_DECODING_PARAM = 2;
  /// < a generic parameter which can be set by the user for demuxing or decoding
  AV_OPT_FLAG_METADATA = 4;
  /// < some data extracted or inserted into the file like title, comment, ...
  AV_OPT_FLAG_AUDIO_PARAM = 8;
  AV_OPT_FLAG_VIDEO_PARAM = 16;
  AV_OPT_FLAG_SUBTITLE_PARAM = 32;
  AV_OPT_FLAG_FILTERING_PARAM = (1 shl 16);

  /// < a generic parameter which can be set by the user for filtering
  ///
Type
  (*
    * AVOption
  *)
  pAVOption = ^TAVOption;

  TAVOption = {packed} record
    name: pAnsiChar;
    (*
      * short English help text
      * @todo What about other languages?
    *)
    help: pAnsiChar;
    (*
      * The offset relative to the context structure where the option
      * value is stored. It should be 0 for named constants.
    *)
    offset: Integer;
    _type: TAVOptionType;
    (*
      * the default value for scalar options
    *)
    default_val: record case cint of 0: (i64: cint64);
    1: (dbl: cdouble);
    2: (str: pAnsiChar);
    (* TODO those are unused now *)
    3: (q: TAVRational);
  end;

min:
double;
/// < minimum valid value for the option
max:
double;
/// < maximum valid value for the option

flags:
Integer;
// FIXME think about enc-audio, ... style flags
(*
  * The logical unit to which the option belongs. Non-constant
  * options and corresponding named constants share the same
  * unit. May be NULL.
*)
_unit:
pAnsiChar;
end;

(*
  // * A single allowed range of values, or a single allowed value.
*)
pAVOptionRange = ^TAVOptionRange;
ppAVOptionRange = ^pAVOptionRange;
TAVOptionRange = {packed} record str: pAnsiChar;
value_min, value_max: double;
/// < For string ranges this represents the min/max length, for dimensions this represents the min/max pixel count
component_min, component_max: double;
/// < For string this represents the unicode range for chars, 0-127 limits to ASCII
is_range:
Integer;
/// < if set to 1 the struct encodes a range, if set to 0 a single value
end;
(*
  // * List of AVOptionRange structs
*)
pAVOptionRanges = ^TAVOptionRanges;
ppAVOptionRanges = ^pAVOptionRanges;
TAVOptionRanges = {packed} record range: ppAVOptionRange;
nb_ranges:
Integer;
end;
//
// #if FF_API_FIND_OPT
(*
  // * Look for an option in obj. Look only for the options which
  // * have the flags set as specified in mask and flags (that is,
  // * for which it is the case that (opt->flags & mask) == flags).
  // *
  // * @param[in] obj a pointer to a struct whose first element is a
  // * pointer to an AVClass
  // * @param[in] name the name of the option to look for
  // * @param[in] unit the unit of the option to look for, or any if NULL
  // * @return a pointer to the option found, or NULL if no option
  // * has been found
  // *
  // * @deprecated use av_opt_find.
*)
// attribute_deprecated
// const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
// #endif
//
// #if FF_API_OLD_AVOPTIONS
(*
  // * Set the field of obj with the given name to value.
  // *
  // * @param[in] obj A struct whose first element is a pointer to an
  // * AVClass.
  // * @param[in] name the name of the field to set
  // * @param[in] val The value to set. If the field is not of a string
  // * type, then the given string is parsed.
  // * SI postfixes and some named scalars are supported.
  // * If the field is of a numeric type, it has to be a numeric or named
  // * scalar. Behavior with more than one scalar and +- infix operators
  // * is undefined.
  // * If the field is of a flags type, it has to be a sequence of numeric
  // * scalars or named flags separated by '+' or '-'. Prefixing a flag
  // * with '+' causes it to be set without affecting the other flags;
  // * similarly, '-' unsets a flag.
  // * @param[out] o_out if non-NULL put here a pointer to the AVOption
  // * found
  // * @param alloc this parameter is currently ignored
  // * @return 0 if the value has been set, or an AVERROR code in case of
  // * error:
  // * AVERROR_OPTION_NOT_FOUND if no matching option exists
  // * AVERROR(ERANGE) if the value is out of range
  // * AVERROR(EINVAL) if the value is not valid
  // * @deprecated use av_opt_set()
*)
// attribute_deprecated
// int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
//
// attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n);
// attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n);
// attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n);
//
// double av_get_double(void *obj, const char *name, const AVOption **o_out);
// AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
// int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
// attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
// attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last);
// #endif
//
(*
  // * Show the obj options.
  // *
  // * @param req_flags requested flags for the options to show. Show only the
  // * options for which it is opt->flags & req_flags.
  // * @param rej_flags rejected flags for the options to show. Show only the
  // * options for which it is !(opt->flags & req_flags).
  // * @param av_log_obj log context to use for showing the options
*)
// int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
//
(*
  // * Set the values of all AVOption fields to their default values.
  // *
  // * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
*)
// void av_opt_set_defaults(void *s);
//
// #if FF_API_OLD_AVOPTIONS
// attribute_deprecated
// void av_opt_set_defaults2(void *s, int mask, int flags);
// #endif
//
(*
  // * Parse the key/value pairs list in opts. For each key/value pair
  // * found, stores the value in the field in ctx that is named like the
  // * key. ctx must be an AVClass context, storing is done using
  // * AVOptions.
  // *
  // * @param opts options string to parse, may be NULL
  // * @param key_val_sep a 0-terminated list of characters used to
  // * separate key from value
  // * @param pairs_sep a 0-terminated list of characters used to separate
  // * two pairs from each other
  // * @return the number of successfully set key/value pairs, or a negative
  // * value corresponding to an AVERROR code in case of error:
  // * AVERROR(EINVAL) if opts cannot be parsed,
  // * the error code issued by av_set_string3() if a key/value pair
  // * cannot be set
*)
// int av_set_options_string(void *ctx, const char *opts,
// const char *key_val_sep, const char *pairs_sep);
//
(*
  // * Parse the key-value pairs list in opts. For each key=value pair found,
  // * set the value of the corresponding option in ctx.
  // *
  // * @param ctx          the AVClass object to set options on
  // * @param opts         the options string, key-value pairs separated by a
  // *                     delimiter
  // * @param shorthand    a NULL-terminated array of options names for shorthand
  // *                     notation: if the first field in opts has no key part,
  // *                     the key is taken from the first element of shorthand;
  // *                     then again for the second, etc., until either opts is
  // *                     finished, shorthand is finished or a named option is
  // *                     found; after that, all options must be named
  // * @param key_val_sep  a 0-terminated list of characters used to separate
  // *                     key from value, for example '='
  // * @param pairs_sep    a 0-terminated list of characters used to separate
  // *                     two pairs from each other, for example ':' or ','
  // * @return  the number of successfully set key=value pairs, or a negative
  // *          value corresponding to an AVERROR code in case of error:
  // *          AVERROR(EINVAL) if opts cannot be parsed,
  // *          the error code issued by av_set_string3() if a key/value pair
  // *          cannot be set
  // *
  // * Options names must use only the following characters: a-z A-Z 0-9 - . / _
  // * Separators must use characters distinct from option names and from each
  // * other.
*)
// int av_opt_set_from_string(void *ctx, const char *opts,
// const char *const *shorthand,
// const char *key_val_sep, const char *pairs_sep);
(*
  // * Free all string and binary options in obj.
*)
// void av_opt_free(void *obj);
//
/// **
// * Check whether a particular flag is set in a flags field.
// *
// * @param field_name the name of the flag field option
// * @param flag_name the name of the flag to check
// * @return non-zero if the flag is set, zero if the flag isn't set,
// *         isn't of the right type, or the flags field doesn't exist.
// */
// int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
//
/// **
// * Set all the options from a given dictionary on an object.
// *
// * @param obj a struct whose first element is a pointer to AVClass
// * @param options options to process. This dictionary will be freed and replaced
// *                by a new one containing all options not found in obj.
// *                Of course this new dictionary needs to be freed by caller
// *                with av_dict_free().
// *
// * @return 0 on success, a negative AVERROR if some option was found in obj,
// *         but could not be set.
// *
// * @see av_dict_copy()
// */
// int av_opt_set_dict(void *obj, struct AVDictionary **options);
//
/// **
// * Extract a key-value pair from the beginning of a string.
// *
// * @param ropts        pointer to the options string, will be updated to
// *                     point to the rest of the string (one of the pairs_sep
// *                     or the final NUL)
// * @param key_val_sep  a 0-terminated list of characters used to separate
// *                     key from value, for example '='
// * @param pairs_sep    a 0-terminated list of characters used to separate
// *                     two pairs from each other, for example ':' or ','
// * @param flags        flags; see the AV_OPT_FLAG_* values below
// * @param rkey         parsed key; must be freed using av_free()
// * @param rval         parsed value; must be freed using av_free()
// *
// * @return  >=0 for success, or a negative value corresponding to an
// *          AVERROR code in case of error; in particular:
// *          AVERROR(EINVAL) if no key is present
// *
// */
// int av_opt_get_key_value(const char **ropts,
// const char *key_val_sep, const char *pairs_sep,
// unsigned flags,
// char **rkey, char **rval);
//
// enum {
//
// /**
// * Accept to parse a value without a key; the key will then be returned
// * as NULL.
// */
// AV_OPT_FLAG_IMPLICIT_KEY = 1,
// };
//
/// **
// * @defgroup opt_eval_funcs Evaluating option strings
// * @{
// * This group of functions can be used to evaluate option strings
// * and get numbers out of them. They do the same thing as av_opt_set(),
// * except the result is written into the caller-supplied pointer.
// *
// * @param obj a struct whose first element is a pointer to AVClass.
// * @param o an option for which the string is to be evaluated.
// * @param val string to be evaluated.
// * @param *_out value of the string will be written here.
// *
// * @return 0 on success, a negative number on failure.
// */
// int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int        *flags_out);
// int av_opt_eval_int   (void *obj, const AVOption *o, const char *val, int        *int_out);
// int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t    *int64_out);
// int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float      *float_out);
// int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double     *double_out);
// int av_opt_eval_q     (void *obj, const AVOption *o, const char *val, AVRational *q_out);
/// **
// * @}
// */
//
// #define AV_OPT_SEARCH_CHILDREN   0x0001 /**< Search in possible children of the
// given object first. */
/// **
// *  The obj passed to av_opt_find() is fake -- only a double pointer to AVClass
// *  instead of a required pointer to a struct containing AVClass. This is
// *  useful for searching for options without needing to allocate the corresponding
// *  object.
// */
// #define AV_OPT_SEARCH_FAKE_OBJ   0x0002
//
/// **
// * Look for an option in an object. Consider only options which
// * have all the specified flags set.
// *
// * @param[in] obj A pointer to a struct whose first element is a
// *                pointer to an AVClass.
// *                Alternatively a double pointer to an AVClass, if
// *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.
// * @param[in] name The name of the option to look for.
// * @param[in] unit When searching for named constants, name of the unit
// *                 it belongs to.
// * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
// * @param search_flags A combination of AV_OPT_SEARCH_*.
// *
// * @return A pointer to the option found, or NULL if no option
// *         was found.
// *
// * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable
// * directly with av_set_string3(). Use special calls which take an options
// * AVDictionary (e.g. avformat_open_input()) to set options found with this
// * flag.
// */
// const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
// int opt_flags, int search_flags);
//
/// **
// * Look for an option in an object. Consider only options which
// * have all the specified flags set.
// *
// * @param[in] obj A pointer to a struct whose first element is a
// *                pointer to an AVClass.
// *                Alternatively a double pointer to an AVClass, if
// *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.
// * @param[in] name The name of the option to look for.
// * @param[in] unit When searching for named constants, name of the unit
// *                 it belongs to.
// * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).
// * @param search_flags A combination of AV_OPT_SEARCH_*.
// * @param[out] target_obj if non-NULL, an object to which the option belongs will be
// * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present
// * in search_flags. This parameter is ignored if search_flags contain
// * AV_OPT_SEARCH_FAKE_OBJ.
// *
// * @return A pointer to the option found, or NULL if no option
// *         was found.
// */
// const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
// int opt_flags, int search_flags, void **target_obj);
//
/// **
// * Iterate over all AVOptions belonging to obj.
// *
// * @param obj an AVOptions-enabled struct or a double pointer to an
// *            AVClass describing it.
// * @param prev result of the previous call to av_opt_next() on this object
// *             or NULL
// * @return next AVOption or NULL
// */
// const AVOption *av_opt_next(void *obj, const AVOption *prev);
//
/// **
// * Iterate over AVOptions-enabled children of obj.
// *
// * @param prev result of a previous call to this function or NULL
// * @return next AVOptions-enabled child or NULL
// */
// void *av_opt_child_next(void *obj, void *prev);
//
/// **
// * Iterate over potential AVOptions-enabled children of parent.
// *
// * @param prev result of a previous call to this function or NULL
// * @return AVClass corresponding to next potential child or NULL
// */
// const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
//
/// **
// * @defgroup opt_set_funcs Option setting functions
// * @{
// * Those functions set the field of obj with the given name to value.
// *
// * @param[in] obj A struct whose first element is a pointer to an AVClass.
// * @param[in] name the name of the field to set
// * @param[in] val The value to set. In case of av_opt_set() if the field is not
// * of a string type, then the given string is parsed.
// * SI postfixes and some named scalars are supported.
// * If the field is of a numeric type, it has to be a numeric or named
// * scalar. Behavior with more than one scalar and +- infix operators
// * is undefined.
// * If the field is of a flags type, it has to be a sequence of numeric
// * scalars or named flags separated by '+' or '-'. Prefixing a flag
// * with '+' causes it to be set without affecting the other flags;
// * similarly, '-' unsets a flag.
// * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
// * is passed here, then the option may be set on a child of obj.
// *
// * @return 0 if the value has been set, or an AVERROR code in case of
// * error:
// * AVERROR_OPTION_NOT_FOUND if no matching option exists
// * AVERROR(ERANGE) if the value is out of range
// * AVERROR(EINVAL) if the value is not valid
// */
// int av_opt_set       (void *obj, const char *name, const char *val, int search_flags);
// int av_opt_set_int   (void *obj, const char *name, int64_t     val, int search_flags);
// int av_opt_set_double(void *obj, const char *name, double      val, int search_flags);
// int av_opt_set_q     (void *obj, const char *name, AVRational  val, int search_flags);
// int av_opt_set_bin   (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
// int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
// int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
// int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
// int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
// int av_opt_set_channel_layout(void *obj, const char *name, int64_t ch_layout, int search_flags);
//
/// **
// * Set a binary option to an integer list.
// *
// * @param obj    AVClass object to set options on
// * @param name   name of the binary option
// * @param val    pointer to an integer list (must have the correct type with
// *               regard to the contents of the list)
// * @param term   list terminator (usually 0 or -1)
// * @param flags  search flags
// */
// #define av_opt_set_int_list(obj, name, val, term, flags) \
// (av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
// AVERROR(EINVAL) : \
// av_opt_set_bin(obj, name, (const uint8_t *)(val), \
// av_int_list_length(val, term) * sizeof(*(val)), flags))
/// **
// * @}
// */
//
/// **
// * @defgroup opt_get_funcs Option getting functions
// * @{
// * Those functions get a value of the option with the given name from an object.
// *
// * @param[in] obj a struct whose first element is a pointer to an AVClass.
// * @param[in] name name of the option to get.
// * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
// * is passed here, then the option may be found in a child of obj.
// * @param[out] out_val value of the option will be written here
// * @return >=0 on success, a negative error code otherwise
// */
/// **
// * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller
// */
// int av_opt_get       (void *obj, const char *name, int search_flags, uint8_t   **out_val);
// int av_opt_get_int   (void *obj, const char *name, int search_flags, int64_t    *out_val);
// int av_opt_get_double(void *obj, const char *name, int search_flags, double     *out_val);
// int av_opt_get_q     (void *obj, const char *name, int search_flags, AVRational *out_val);
// int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
// int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
// int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
// int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
// int av_opt_get_channel_layout(void *obj, const char *name, int search_flags, int64_t *ch_layout);
/// **
// * @}
// */
/// **
// * Gets a pointer to the requested field in a struct.
// * This function allows accessing a struct even when its fields are moved or
// * renamed since the application making the access has been compiled,
// *
// * @returns a pointer to the field, it can be cast to the correct type and read
// *          or written to.
// */
// void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
//
/// **
// * Free an AVOptionRanges struct and set it to NULL.
// */
// void av_opt_freep_ranges(AVOptionRanges **ranges);
//
/// **
// * Get a list of allowed ranges for the given option.
// *
// * The returned list may depend on other fields in obj like for example profile.
// *
// * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
// *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
// *
// * The result must be freed with av_opt_freep_ranges.
// *
// * @return >= 0 on success, a negative errro code otherwise
// */
// int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
//
/// **
// * Get a default list of allowed ranges for the given option.
// *
// * This list is constructed without using the AVClass.query_ranges() callback
// * and can be used as fallback from within the callback.
// *
// * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
// *              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
// *
// * The result must be freed with av_opt_free_ranges.
// *
// * @return >= 0 on success, a negative errro code otherwise
// */
// int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
//
/// **
// * @}
// */

implementation

end.