ffmpeg/libavutil/opt.h

409 lines
16 KiB
C

/*
* 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
*/
#ifndef AVUTIL_OPT_H
#define AVUTIL_OPT_H
/**
* @file
* AVOptions
*/
#include "rational.h"
#include "avutil.h"
#include "dict.h"
#include "log.h"
enum AVOptionType{
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,
#if 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
};
/**
* AVOption
*/
typedef struct AVOption {
const char *name;
/**
* short English help text
* @todo What about other languages?
*/
const char *help;
/**
* The offset relative to the context structure where the option
* value is stored. It should be 0 for named constants.
*/
int offset;
enum AVOptionType type;
/**
* the default value for scalar options
*/
union {
double dbl;
const char *str;
/* TODO those are unused now */
int64_t i64;
AVRational q;
} default_val;
double min; ///< minimum valid value for the option
double max; ///< maximum valid value for the option
int flags;
#define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
#define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
#define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
#define AV_OPT_FLAG_AUDIO_PARAM 8
#define AV_OPT_FLAG_VIDEO_PARAM 16
#define AV_OPT_FLAG_SUBTITLE_PARAM 32
//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.
*/
const char *unit;
} AVOption;
#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);
attribute_deprecated double av_get_double(void *obj, const char *name, const AVOption **o_out);
attribute_deprecated AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
attribute_deprecated 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);
/**
* 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);
/**
* @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);
/**
* @}
*/
/**
* @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 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);
/**
* @}
*/
#endif /* AVUTIL_OPT_H */