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FFmpeg/libavcodec/opt.h

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/*
* 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 AVCODEC_OPT_H
#define AVCODEC_OPT_H
/**
* @file opt.h
* AVOptions
*/
#include "libavutil/rational.h"
enum AVOptionType{
FF_OPT_TYPE_FLAGS,
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,
};
/**
* 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
*/
double 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;
/**
* Looks for an option in \p obj. Looks only for the options which
* have the flags set as specified in \p mask and \p 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
*/
const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
#if LIBAVCODEC_VERSION_MAJOR < 53
/**
* @see av_set_string2()
*/
attribute_deprecated const AVOption *av_set_string(void *obj, const char *name, const char *val);
/**
* @return a pointer to the AVOption corresponding to the field set or
* NULL if no matching AVOption exists, or if the value \p val is not
* valid
* @see av_set_string3()
*/
attribute_deprecated const AVOption *av_set_string2(void *obj, const char *name, const char *val, int alloc);
#endif
/**
* Sets 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 when 1 then the old value will be av_freed() and the
* new av_strduped()
* when 0 then no av_free() nor av_strdup() will be used
* @return 0 if the value has been set, an AVERROR* error code if no
* matching option exists, or if the value \p val is not valid
*/
int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
const AVOption *av_set_double(void *obj, const char *name, double n);
const AVOption *av_set_q(void *obj, const char *name, AVRational n);
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);
const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
const AVOption *av_next_option(void *obj, const AVOption *last);
int av_opt_show(void *obj, void *av_log_obj);
void av_opt_set_defaults(void *s);
void av_opt_set_defaults2(void *s, int mask, int flags);
#endif /* AVCODEC_OPT_H */