libavcodec/opt.h

   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 AVCODEC_OPT_H
  23 #define AVCODEC_OPT_H
  24
  25 /**
  26  * @file libavcodec/opt.h
  27  * AVOptions
  28  */
  29
  30 #include "libavutil/rational.h"
  31 #include "avcodec.h"
  32
  33 enum AVOptionType{
  34     FF_OPT_TYPE_FLAGS,
  35     FF_OPT_TYPE_INT,
  36     FF_OPT_TYPE_INT64,
  37     FF_OPT_TYPE_DOUBLE,
  38     FF_OPT_TYPE_FLOAT,
  39     FF_OPT_TYPE_STRING,
  40     FF_OPT_TYPE_RATIONAL,
  41     FF_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length
  42     FF_OPT_TYPE_CONST=128,
  43 };
  44
  45 /**
  46  * AVOption
  47  */
  48 typedef struct AVOption {
  49     const char *name;
  50
  51     /**
  52      * short English help text
  53      * @todo What about other languages?
  54      */
  55     const char *help;
  56
  57     /**
  58      * The offset relative to the context structure where the option
  59      * value is stored. It should be 0 for named constants.
  60      */
  61     int offset;
  62     enum AVOptionType type;
  63
  64     /**
  65      * the default value for scalar options
  66      */
  67     double default_val;
  68     double min;                 ///< minimum valid value for the option
  69     double max;                 ///< maximum valid value for the option
  70
  71     int flags;
  72 #define AV_OPT_FLAG_ENCODING_PARAM  1   ///< a generic parameter which can be set by the user for muxing or encoding
  73 #define AV_OPT_FLAG_DECODING_PARAM  2   ///< a generic parameter which can be set by the user for demuxing or decoding
  74 #define AV_OPT_FLAG_METADATA        4   ///< some data extracted or inserted into the file like title, comment, ...
  75 #define AV_OPT_FLAG_AUDIO_PARAM     8
  76 #define AV_OPT_FLAG_VIDEO_PARAM     16
  77 #define AV_OPT_FLAG_SUBTITLE_PARAM  32
  78 //FIXME think about enc-audio, ... style flags
  79
  80     /**
  81      * The logical unit to which the option belongs. Non-constant
  82      * options and corresponding named constants share the same
  83      * unit. May be NULL.
  84      */
  85     const char *unit;
  86 } AVOption;
  87
  88 /**
  89  * AVOption2.
  90  * THIS IS NOT PART OF THE API/ABI YET!
  91  * This is identical to AVOption except that default_val was replaced by
  92  * an union, it should be compatible with AVOption on normal platforms.
  93  */
  94 typedef struct AVOption2 {
  95     const char *name;
  96
  97     /**
  98      * short English help text
  99      * @todo What about other languages?
 100      */
 101     const char *help;
 102
 103     /**
 104      * The offset relative to the context structure where the option
 105      * value is stored. It should be 0 for named constants.
 106      */
 107     int offset;
 108     enum AVOptionType type;
 109
 110     /**
 111      * the default value for scalar options
 112      */
 113     union {
 114         double dbl;
 115         const char *str;
 116     } default_val;
 117
 118     double min;                 ///< minimum valid value for the option
 119     double max;                 ///< maximum valid value for the option
 120
 121     int flags;
 122 /*
 123 #define AV_OPT_FLAG_ENCODING_PARAM  1   ///< a generic parameter which can be set by the user for muxing or encoding
 124 #define AV_OPT_FLAG_DECODING_PARAM  2   ///< a generic parameter which can be set by the user for demuxing or decoding
 125 #define AV_OPT_FLAG_METADATA        4   ///< some data extracted or inserted into the file like title, comment, ...
 126 #define AV_OPT_FLAG_AUDIO_PARAM     8
 127 #define AV_OPT_FLAG_VIDEO_PARAM     16
 128 #define AV_OPT_FLAG_SUBTITLE_PARAM  32
 129 */
 130 //FIXME think about enc-audio, ... style flags
 131
 132     /**
 133      * The logical unit to which the option belongs. Non-constant
 134      * options and corresponding named constants share the same
 135      * unit. May be NULL.
 136      */
 137     const char *unit;
 138 } AVOption2;
 139
 140
 141 /**
 142  * Looks for an option in obj. Looks only for the options which
 143  * have the flags set as specified in mask and flags (that is,
 144  * for which it is the case that opt->flags & mask == flags).
 145  *
 146  * @param[in] obj a pointer to a struct whose first element is a
 147  * pointer to an AVClass
 148  * @param[in] name the name of the option to look for
 149  * @param[in] unit the unit of the option to look for, or any if NULL
 150  * @return a pointer to the option found, or NULL if no option
 151  * has been found
 152  */
 153 const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
 154
 155 #if LIBAVCODEC_VERSION_MAJOR < 53
 156 /**
 157  * @see av_set_string2()
 158  */
 159 attribute_deprecated const AVOption *av_set_string(void *obj, const char *name, const char *val);
 160
 161 /**
 162  * @return a pointer to the AVOption corresponding to the field set or
 163  * NULL if no matching AVOption exists, or if the value val is not
 164  * valid
 165  * @see av_set_string3()
 166  */
 167 attribute_deprecated const AVOption *av_set_string2(void *obj, const char *name, const char *val, int alloc);
 168 #endif
 169
 170 /**
 171  * Sets the field of obj with the given name to value.
 172  *
 173  * @param[in] obj A struct whose first element is a pointer to an
 174  * AVClass.
 175  * @param[in] name the name of the field to set
 176  * @param[in] val The value to set. If the field is not of a string
 177  * type, then the given string is parsed.
 178  * SI postfixes and some named scalars are supported.
 179  * If the field is of a numeric type, it has to be a numeric or named
 180  * scalar. Behavior with more than one scalar and +- infix operators
 181  * is undefined.
 182  * If the field is of a flags type, it has to be a sequence of numeric
 183  * scalars or named flags separated by '+' or '-'. Prefixing a flag
 184  * with '+' causes it to be set without affecting the other flags;
 185  * similarly, '-' unsets a flag.
 186  * @param[out] o_out if non-NULL put here a pointer to the AVOption
 187  * found
 188  * @param alloc when 1 then the old value will be av_freed() and the
 189  *                     new av_strduped()
 190  *              when 0 then no av_free() nor av_strdup() will be used
 191  * @return 0 if the value has been set, or an AVERROR code in case of
 192  * error:
 193  * AVERROR(ENOENT) if no matching option exists
 194  * AVERROR(ERANGE) if the value is out of range
 195  * AVERROR(EINVAL) if the value is not valid
 196  */
 197 int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
 198
 199 const AVOption *av_set_double(void *obj, const char *name, double n);
 200 const AVOption *av_set_q(void *obj, const char *name, AVRational n);
 201 const AVOption *av_set_int(void *obj, const char *name, int64_t n);
 202 double av_get_double(void *obj, const char *name, const AVOption **o_out);
 203 AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
 204 int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
 205 const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
 206 const AVOption *av_next_option(void *obj, const AVOption *last);
 207 int av_opt_show(void *obj, void *av_log_obj);
 208 void av_opt_set_defaults(void *s);
 209 void av_opt_set_defaults2(void *s, int mask, int flags);
 210
 211 #endif /* AVCODEC_OPT_H */