05c6dea89f301f06fd8addde4d717f25bbac9511
[libav.git] / 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 /**
90 * Looks for an option in \p obj. Looks only for the options which
91 * have the flags set as specified in \p mask and \p flags (that is,
92 * for which it is the case that opt->flags & mask == flags).
93 *
94 * @param[in] obj a pointer to a struct whose first element is a
95 * pointer to an AVClass
96 * @param[in] name the name of the option to look for
97 * @param[in] unit the unit of the option to look for, or any if NULL
98 * @return a pointer to the option found, or NULL if no option
99 * has been found
100 */
101 const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
102
103 #if LIBAVCODEC_VERSION_MAJOR < 53
104 /**
105 * @see av_set_string2()
106 */
107 attribute_deprecated const AVOption *av_set_string(void *obj, const char *name, const char *val);
108
109 /**
110 * @return a pointer to the AVOption corresponding to the field set or
111 * NULL if no matching AVOption exists, or if the value \p val is not
112 * valid
113 * @see av_set_string3()
114 */
115 attribute_deprecated const AVOption *av_set_string2(void *obj, const char *name, const char *val, int alloc);
116 #endif
117
118 /**
119 * Sets the field of obj with the given name to value.
120 *
121 * @param[in] obj A struct whose first element is a pointer to an
122 * AVClass.
123 * @param[in] name the name of the field to set
124 * @param[in] val The value to set. If the field is not of a string
125 * type, then the given string is parsed.
126 * SI postfixes and some named scalars are supported.
127 * If the field is of a numeric type, it has to be a numeric or named
128 * scalar. Behavior with more than one scalar and +- infix operators
129 * is undefined.
130 * If the field is of a flags type, it has to be a sequence of numeric
131 * scalars or named flags separated by '+' or '-'. Prefixing a flag
132 * with '+' causes it to be set without affecting the other flags;
133 * similarly, '-' unsets a flag.
134 * @param[out] o_out if non-NULL put here a pointer to the AVOption
135 * found
136 * @param alloc when 1 then the old value will be av_freed() and the
137 * new av_strduped()
138 * when 0 then no av_free() nor av_strdup() will be used
139 * @return 0 if the value has been set, or an AVERROR code in case of
140 * error:
141 * AVERROR(ENOENT) if no matching option exists
142 * AVERROR(ERANGE) if the value is out of range
143 * AVERROR(EINVAL) if the value is not valid
144 */
145 int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
146
147 const AVOption *av_set_double(void *obj, const char *name, double n);
148 const AVOption *av_set_q(void *obj, const char *name, AVRational n);
149 const AVOption *av_set_int(void *obj, const char *name, int64_t n);
150 double av_get_double(void *obj, const char *name, const AVOption **o_out);
151 AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
152 int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
153 const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
154 const AVOption *av_next_option(void *obj, const AVOption *last);
155 int av_opt_show(void *obj, void *av_log_obj);
156 void av_opt_set_defaults(void *s);
157 void av_opt_set_defaults2(void *s, int mask, int flags);
158
159 #endif /* AVCODEC_OPT_H */