opt.h
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上传日期:2022-07-11
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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 "rational.h"
- //#include "avcodec.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 */