ffmpeg: don't abuse a global for passing frame size from input to output
[libav.git] / libavutil / opt.h
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1/*
2 * AVOptions
3 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
4 *
2912e87a 5 * This file is part of Libav.
6ed04040 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 18 * License along with Libav; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#ifndef AVUTIL_OPT_H
23#define AVUTIL_OPT_H
24
25/**
26 * @file
27 * AVOptions
28 */
29
30#include "rational.h"
31#include "avutil.h"
32
33enum 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 */
48typedef 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 */
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67 union {
68 double dbl;
69 const char *str;
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70 /* TODO those are unused now */
71 int64_t i64;
72 AVRational q;
6ed04040 73 } default_val;
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74 double min; ///< minimum valid value for the option
75 double max; ///< maximum valid value for the option
76
77 int flags;
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78#define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
79#define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
80#define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
81#define AV_OPT_FLAG_AUDIO_PARAM 8
82#define AV_OPT_FLAG_VIDEO_PARAM 16
83#define AV_OPT_FLAG_SUBTITLE_PARAM 32
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84//FIXME think about enc-audio, ... style flags
85
86 /**
87 * The logical unit to which the option belongs. Non-constant
88 * options and corresponding named constants share the same
89 * unit. May be NULL.
90 */
91 const char *unit;
b6675279 92} AVOption;
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93
94/**
95 * Look for an option in obj. Look only for the options which
96 * have the flags set as specified in mask and flags (that is,
97 * for which it is the case that opt->flags & mask == flags).
98 *
99 * @param[in] obj a pointer to a struct whose first element is a
100 * pointer to an AVClass
101 * @param[in] name the name of the option to look for
102 * @param[in] unit the unit of the option to look for, or any if NULL
103 * @return a pointer to the option found, or NULL if no option
104 * has been found
105 */
106const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
107
108/**
109 * Set the field of obj with the given name to value.
110 *
111 * @param[in] obj A struct whose first element is a pointer to an
112 * AVClass.
113 * @param[in] name the name of the field to set
114 * @param[in] val The value to set. If the field is not of a string
115 * type, then the given string is parsed.
116 * SI postfixes and some named scalars are supported.
117 * If the field is of a numeric type, it has to be a numeric or named
118 * scalar. Behavior with more than one scalar and +- infix operators
119 * is undefined.
120 * If the field is of a flags type, it has to be a sequence of numeric
121 * scalars or named flags separated by '+' or '-'. Prefixing a flag
122 * with '+' causes it to be set without affecting the other flags;
123 * similarly, '-' unsets a flag.
124 * @param[out] o_out if non-NULL put here a pointer to the AVOption
125 * found
126 * @param alloc when 1 then the old value will be av_freed() and the
127 * new av_strduped()
128 * when 0 then no av_free() nor av_strdup() will be used
129 * @return 0 if the value has been set, or an AVERROR code in case of
130 * error:
131 * AVERROR(ENOENT) if no matching option exists
132 * AVERROR(ERANGE) if the value is out of range
133 * AVERROR(EINVAL) if the value is not valid
134 */
135int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
136
137const AVOption *av_set_double(void *obj, const char *name, double n);
138const AVOption *av_set_q(void *obj, const char *name, AVRational n);
139const AVOption *av_set_int(void *obj, const char *name, int64_t n);
140double av_get_double(void *obj, const char *name, const AVOption **o_out);
141AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
142int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
143const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
144const AVOption *av_next_option(void *obj, const AVOption *last);
145
146/**
147 * Show the obj options.
148 *
149 * @param req_flags requested flags for the options to show. Show only the
150 * options for which it is opt->flags & req_flags.
151 * @param rej_flags rejected flags for the options to show. Show only the
152 * options for which it is !(opt->flags & req_flags).
153 * @param av_log_obj log context to use for showing the options
154 */
155int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
156
157void av_opt_set_defaults(void *s);
158void av_opt_set_defaults2(void *s, int mask, int flags);
159
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160/**
161 * Parse the key/value pairs list in opts. For each key/value pair
162 * found, stores the value in the field in ctx that is named like the
163 * key. ctx must be an AVClass context, storing is done using
164 * AVOptions.
165 *
166 * @param key_val_sep a 0-terminated list of characters used to
167 * separate key from value
168 * @param pairs_sep a 0-terminated list of characters used to separate
169 * two pairs from each other
170 * @return the number of successfully set key/value pairs, or a negative
171 * value corresponding to an AVERROR code in case of error:
172 * AVERROR(EINVAL) if opts cannot be parsed,
173 * the error code issued by av_set_string3() if a key/value pair
174 * cannot be set
175 */
176int av_set_options_string(void *ctx, const char *opts,
177 const char *key_val_sep, const char *pairs_sep);
178
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179/**
180 * Free all string and binary options in obj.
181 */
182void av_opt_free(void *obj);
183
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184/**
185 * Check whether a particular flag is set in a flags field.
186 *
187 * @param field_name the name of the flag field option
188 * @param flag_name the name of the flag to check
189 * @return non-zero if the flag is set, zero if the flag isn't set,
190 * isn't of the right type, or the flags field doesn't exist.
191 */
192int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);
193
6ed04040 194#endif /* AVUTIL_OPT_H */