/* * AVOptions * copyright (c) 2005 Michael Niedermayer <[email protected]> * * 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 AVUTIL_OPT_H #define AVUTIL_OPT_H /** * @file * AVOptions */ #include "rational.h" #include "avutil.h" #include "channel_layout.h" #include "dict.h" #include "log.h" #include "pixfmt.h" #include "samplefmt.h" /** * @defgroup avoptions AVOptions * @ingroup lavu_data * @{ * AVOptions provide a generic system to declare options on arbitrary structs * ("objects"). An option can have a help text, a type and a range of possible * values. Options may then be enumerated, read and written to. * * There are two modes of access to members of AVOption and its child structs. * One is called 'native access', and refers to access from the code that * declares the AVOption in question. The other is 'foreign access', and refers * to access from other code. * * Certain struct members in this header are documented as 'native access only' * or similar - it means that only the code that declared the AVOption in * question is allowed to access the field. This allows us to extend the * semantics of those fields without breaking API compatibility. * * @section avoptions_scope Scope of AVOptions * * AVOptions is designed to support any set of multimedia configuration options * that can be defined at compile-time. Although it is mainly used to expose * FFmpeg options, you are welcome to adapt it to your own use case. * * No single approach can ever fully solve the problem of configuration, * but please submit a patch if you believe you have found a problem * that is best solved by extending AVOptions. * * @section avoptions_implement Implementing AVOptions * This section describes how to add AVOptions capabilities to a struct. * * All AVOptions-related information is stored in an AVClass. Therefore * the first member of the struct should be a pointer to an AVClass describing it. * The option field of the AVClass must be set to a NULL-terminated static array * of AVOptions. Each AVOption must have a non-empty name, a type, a default * value and for number-type AVOptions also a range of allowed values. It must * also declare an offset in bytes from the start of the struct, where the field * associated with this AVOption is located. Other fields in the AVOption struct * should also be set when applicable, but are not required. * * The following example illustrates an AVOptions-enabled struct: * @code * typedef struct test_struct { * const AVClass *class; * int int_opt; * char *str_opt; * uint8_t *bin_opt; * int bin_len; * } test_struct; * * static const AVOption test_options[] = { * { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt), * AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX }, * { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt), * AV_OPT_TYPE_STRING }, * { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt), * AV_OPT_TYPE_BINARY }, * { NULL }, * }; * * static const AVClass test_class = { * .class_name = "test class", * .item_name = av_default_item_name, * .option = test_options, * .version = LIBAVUTIL_VERSION_INT, * }; * @endcode * * Next, when allocating your struct, you must ensure that the AVClass pointer * is set to the correct value. Then, av_opt_set_defaults() can be called to * initialize defaults. After that the struct is ready to be used with the * AVOptions API. * * When cleaning up, you may use the av_opt_free() function to automatically * free all the allocated string and binary options. * * Continuing with the above example: * * @code * test_struct *alloc_test_struct(void) * { * test_struct *ret = av_mallocz(sizeof(*ret)); * ret->class = &test_class; * av_opt_set_defaults(ret); * return ret; * } * void free_test_struct(test_struct **foo) * { * av_opt_free(*foo); * av_freep(foo); * } * @endcode * * @subsection avoptions_implement_nesting Nesting * It may happen that an AVOptions-enabled struct contains another * AVOptions-enabled struct as a member (e.g. AVCodecContext in * libavcodec exports generic options, while its priv_data field exports * codec-specific options). In such a case, it is possible to set up the * parent struct to export a child's options. To do that, simply * implement AVClass.child_next() and AVClass.child_class_iterate() in the * parent struct's AVClass. * Assuming that the test_struct from above now also contains a * child_struct field: * * @code * typedef struct child_struct { * AVClass *class; * int flags_opt; * } child_struct; * static const AVOption child_opts[] = { * { "test_flags", "This is a test option of flags type.", * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX }, * { NULL }, * }; * static const AVClass child_class = { * .class_name = "child class", * .item_name = av_default_item_name, * .option = child_opts, * .version = LIBAVUTIL_VERSION_INT, * }; * * void *child_next(void *obj, void *prev) * { * test_struct *t = obj; * if (!prev && t->child_struct) * return t->child_struct; * return NULL * } * const AVClass child_class_iterate(void **iter) * { * const AVClass *c = *iter ? NULL : &child_class; * *iter = (void*)(uintptr_t)c; * return c; * } * @endcode * Putting child_next() and child_class_iterate() as defined above into * test_class will now make child_struct's options accessible through * test_struct (again, proper setup as described above needs to be done on * child_struct right after it is created). * * From the above example it might not be clear why both child_next() * and child_class_iterate() are needed. The distinction is that child_next() * iterates over actually existing objects, while child_class_iterate() * iterates over all possible child classes. E.g. if an AVCodecContext * was initialized to use a codec which has private options, then its * child_next() will return AVCodecContext.priv_data and finish * iterating. OTOH child_class_iterate() on AVCodecContext.av_class will * iterate over all available codecs with private options. * * @subsection avoptions_implement_named_constants Named constants * It is possible to create named constants for options. Simply set the unit * field of the option the constants should apply to a string and * create the constants themselves as options of type AV_OPT_TYPE_CONST * with their unit field set to the same string. * Their default_val field should contain the value of the named * constant. * For example, to add some named constants for the test_flags option * above, put the following into the child_opts array: * @code * { "test_flags", "This is a test option of flags type.", * offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" }, * { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" }, * @endcode * * @section avoptions_use Using AVOptions * This section deals with accessing options in an AVOptions-enabled struct. * Such structs in FFmpeg are e.g. AVCodecContext in libavcodec or * AVFormatContext in libavformat. * * @subsection avoptions_use_examine Examining AVOptions * The basic functions for examining options are av_opt_next(), which iterates * over all options defined for one object, and av_opt_find(), which searches * for an option with the given name. * * The situation is more complicated with nesting. An AVOptions-enabled struct * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag * to av_opt_find() will make the function search children recursively. * * For enumerating there are basically two cases. The first is when you want to * get all options that may potentially exist on the struct and its children * (e.g. when constructing documentation). In that case you should call * av_opt_child_class_iterate() recursively on the parent struct's AVClass. The * second case is when you have an already initialized struct with all its * children and you want to get all options that can be actually written or read * from it. In that case you should call av_opt_child_next() recursively (and * av_opt_next() on each result). * * @subsection avoptions_use_get_set Reading and writing AVOptions * When setting options, you often have a string read directly from the * user. In such a case, simply passing it to av_opt_set() is enough. For * non-string type options, av_opt_set() will parse the string according to the * option type. * * Similarly av_opt_get() will read any option type and convert it to a string * which will be returned. Do not forget that the string is allocated, so you * have to free it with av_free(). * * In some cases it may be more convenient to put all options into an * AVDictionary and call av_opt_set_dict() on it. A specific case of this * are the format/codec open functions in lavf/lavc which take a dictionary * filled with option as a parameter. This makes it possible to set some options * that cannot be set otherwise, since e.g. the input file format is not known * before the file is actually opened. */ enum AVOptionType{ … }; /** * A generic parameter which can be set by the user for muxing or encoding. */ #define AV_OPT_FLAG_ENCODING_PARAM … /** * A generic parameter which can be set by the user for demuxing or decoding. */ #define AV_OPT_FLAG_DECODING_PARAM … #define AV_OPT_FLAG_AUDIO_PARAM … #define AV_OPT_FLAG_VIDEO_PARAM … #define AV_OPT_FLAG_SUBTITLE_PARAM … /** * The option is intended for exporting values to the caller. */ #define AV_OPT_FLAG_EXPORT … /** * The option may not be set through the AVOptions API, only read. * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set. */ #define AV_OPT_FLAG_READONLY … /** * A generic parameter which can be set by the user for bit stream filtering. */ #define AV_OPT_FLAG_BSF_PARAM … /** * A generic parameter which can be set by the user at runtime. */ #define AV_OPT_FLAG_RUNTIME_PARAM … /** * A generic parameter which can be set by the user for filtering. */ #define AV_OPT_FLAG_FILTERING_PARAM … /** * Set if option is deprecated, users should refer to AVOption.help text for * more information. */ #define AV_OPT_FLAG_DEPRECATED … /** * Set if option constants can also reside in child objects. */ #define AV_OPT_FLAG_CHILD_CONSTS … /** * May be set as default_val for AV_OPT_TYPE_FLAG_ARRAY options. */ AVOptionArrayDef; /** * AVOption */ AVOption; /** * A single allowed range of values, or a single allowed value. */ AVOptionRange; /** * List of AVOptionRange structs. */ AVOptionRanges; /** * @defgroup opt_mng AVOption (un)initialization and inspection. * @{ */ /** * Set the values of all AVOption fields to their default values. * * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) */ void av_opt_set_defaults(void *s); /** * Set the values of all AVOption fields to their default values. Only these * AVOption fields for which (opt->flags & mask) == flags will have their * default applied to s. * * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass) * @param mask combination of AV_OPT_FLAG_* * @param flags combination of AV_OPT_FLAG_* */ void av_opt_set_defaults2(void *s, int mask, int flags); /** * Free all allocated objects in obj. */ void av_opt_free(void *obj); /** * Iterate over all AVOptions belonging to obj. * * @param obj an AVOptions-enabled struct or a double pointer to an * AVClass describing it. * @param prev result of the previous call to av_opt_next() on this object * or NULL * @return next AVOption or NULL */ const AVOption *av_opt_next(const void *obj, const AVOption *prev); /** * Iterate over AVOptions-enabled children of obj. * * @param prev result of a previous call to this function or NULL * @return next AVOptions-enabled child or NULL */ void *av_opt_child_next(void *obj, void *prev); /** * Iterate over potential AVOptions-enabled children of parent. * * @param iter a pointer where iteration state is stored. * @return AVClass corresponding to next potential child or NULL */ const AVClass *av_opt_child_class_iterate(const AVClass *parent, void **iter); #define AV_OPT_SEARCH_CHILDREN … /** * The obj passed to av_opt_find() is fake -- only a double pointer to AVClass * instead of a required pointer to a struct containing AVClass. This is * useful for searching for options without needing to allocate the corresponding * object. */ #define AV_OPT_SEARCH_FAKE_OBJ … /** * In av_opt_get, return NULL if the option has a pointer type and is set to NULL, * rather than returning an empty string. */ #define AV_OPT_ALLOW_NULL … /** * Allows av_opt_query_ranges and av_opt_query_ranges_default to return more than * one component for certain option types. * @see AVOptionRanges for details. */ #define AV_OPT_MULTI_COMPONENT_RANGE … /** * Look for an option in an object. Consider only options which * have all the specified flags set. * * @param[in] obj A pointer to a struct whose first element is a * pointer to an AVClass. * Alternatively a double pointer to an AVClass, if * AV_OPT_SEARCH_FAKE_OBJ search flag is set. * @param[in] name The name of the option to look for. * @param[in] unit When searching for named constants, name of the unit * it belongs to. * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). * @param search_flags A combination of AV_OPT_SEARCH_*. * * @return A pointer to the option found, or NULL if no option * was found. * * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable * directly with av_opt_set(). Use special calls which take an options * AVDictionary (e.g. avformat_open_input()) to set options found with this * flag. */ const AVOption *av_opt_find(void *obj, const char *name, const char *unit, int opt_flags, int search_flags); /** * Look for an option in an object. Consider only options which * have all the specified flags set. * * @param[in] obj A pointer to a struct whose first element is a * pointer to an AVClass. * Alternatively a double pointer to an AVClass, if * AV_OPT_SEARCH_FAKE_OBJ search flag is set. * @param[in] name The name of the option to look for. * @param[in] unit When searching for named constants, name of the unit * it belongs to. * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG). * @param search_flags A combination of AV_OPT_SEARCH_*. * @param[out] target_obj if non-NULL, an object to which the option belongs will be * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present * in search_flags. This parameter is ignored if search_flags contain * AV_OPT_SEARCH_FAKE_OBJ. * * @return A pointer to the option found, or NULL if no option * was found. */ const AVOption *av_opt_find2(void *obj, const char *name, const char *unit, int opt_flags, int search_flags, void **target_obj); /** * Show the obj options. * * @param req_flags requested flags for the options to show. Show only the * options for which it is opt->flags & req_flags. * @param rej_flags rejected flags for the options to show. Show only the * options for which it is !(opt->flags & req_flags). * @param av_log_obj log context to use for showing the options */ int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags); /** * Extract a key-value pair from the beginning of a string. * * @param ropts pointer to the options string, will be updated to * point to the rest of the string (one of the pairs_sep * or the final NUL) * @param key_val_sep a 0-terminated list of characters used to separate * key from value, for example '=' * @param pairs_sep a 0-terminated list of characters used to separate * two pairs from each other, for example ':' or ',' * @param flags flags; see the AV_OPT_FLAG_* values below * @param rkey parsed key; must be freed using av_free() * @param rval parsed value; must be freed using av_free() * * @return >=0 for success, or a negative value corresponding to an * AVERROR code in case of error; in particular: * AVERROR(EINVAL) if no key is present * */ int av_opt_get_key_value(const char **ropts, const char *key_val_sep, const char *pairs_sep, unsigned flags, char **rkey, char **rval); enum { … }; /** * @} */ /** * @defgroup opt_write Setting and modifying option values * @{ */ /** * Parse the key/value pairs list in opts. For each key/value pair * found, stores the value in the field in ctx that is named like the * key. ctx must be an AVClass context, storing is done using * AVOptions. * * @param opts options string to parse, may be NULL * @param key_val_sep a 0-terminated list of characters used to * separate key from value * @param pairs_sep a 0-terminated list of characters used to separate * two pairs from each other * @return the number of successfully set key/value pairs, or a negative * value corresponding to an AVERROR code in case of error: * AVERROR(EINVAL) if opts cannot be parsed, * the error code issued by av_opt_set() if a key/value pair * cannot be set */ int av_set_options_string(void *ctx, const char *opts, const char *key_val_sep, const char *pairs_sep); /** * Parse the key-value pairs list in opts. For each key=value pair found, * set the value of the corresponding option in ctx. * * @param ctx the AVClass object to set options on * @param opts the options string, key-value pairs separated by a * delimiter * @param shorthand a NULL-terminated array of options names for shorthand * notation: if the first field in opts has no key part, * the key is taken from the first element of shorthand; * then again for the second, etc., until either opts is * finished, shorthand is finished or a named option is * found; after that, all options must be named * @param key_val_sep a 0-terminated list of characters used to separate * key from value, for example '=' * @param pairs_sep a 0-terminated list of characters used to separate * two pairs from each other, for example ':' or ',' * @return the number of successfully set key=value pairs, or a negative * value corresponding to an AVERROR code in case of error: * AVERROR(EINVAL) if opts cannot be parsed, * the error code issued by av_set_string3() if a key/value pair * cannot be set * * Options names must use only the following characters: a-z A-Z 0-9 - . / _ * Separators must use characters distinct from option names and from each * other. */ int av_opt_set_from_string(void *ctx, const char *opts, const char *const *shorthand, const char *key_val_sep, const char *pairs_sep); /** * Set all the options from a given dictionary on an object. * * @param obj a struct whose first element is a pointer to AVClass * @param options options to process. This dictionary will be freed and replaced * by a new one containing all options not found in obj. * Of course this new dictionary needs to be freed by caller * with av_dict_free(). * * @return 0 on success, a negative AVERROR if some option was found in obj, * but could not be set. * * @see av_dict_copy() */ int av_opt_set_dict(void *obj, struct AVDictionary **options); /** * Set all the options from a given dictionary on an object. * * @param obj a struct whose first element is a pointer to AVClass * @param options options to process. This dictionary will be freed and replaced * by a new one containing all options not found in obj. * Of course this new dictionary needs to be freed by caller * with av_dict_free(). * @param search_flags A combination of AV_OPT_SEARCH_*. * * @return 0 on success, a negative AVERROR if some option was found in obj, * but could not be set. * * @see av_dict_copy() */ int av_opt_set_dict2(void *obj, struct AVDictionary **options, int search_flags); /** * Copy options from src object into dest object. * * The underlying AVClass of both src and dest must coincide. The guarantee * below does not apply if this is not fulfilled. * * Options that require memory allocation (e.g. string or binary) are malloc'ed in dest object. * Original memory allocated for such options is freed unless both src and dest options points to the same memory. * * Even on error it is guaranteed that allocated options from src and dest * no longer alias each other afterwards; in particular calling av_opt_free() * on both src and dest is safe afterwards if dest has been memdup'ed from src. * * @param dest Object to copy from * @param src Object to copy into * @return 0 on success, negative on error */ int av_opt_copy(void *dest, const void *src); /** * @defgroup opt_set_funcs Option setting functions * @{ * Those functions set 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. In case of av_opt_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. * If the field is of a dictionary type, it has to be a ':' separated list of * key=value parameters. Values containing ':' special characters must be * escaped. * @param search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN * is passed here, then the option may be set on a child of obj. * * @return 0 if the value has been set, or an AVERROR code in case of * error: * AVERROR_OPTION_NOT_FOUND if no matching option exists * AVERROR(ERANGE) if the value is out of range * AVERROR(EINVAL) if the value is not valid */ int av_opt_set (void *obj, const char *name, const char *val, int search_flags); int av_opt_set_int (void *obj, const char *name, int64_t val, int search_flags); int av_opt_set_double (void *obj, const char *name, double val, int search_flags); int av_opt_set_q (void *obj, const char *name, AVRational val, int search_flags); int av_opt_set_bin (void *obj, const char *name, const uint8_t *val, int size, int search_flags); int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags); int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags); int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags); int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags); /** * @note Any old chlayout present is discarded and replaced with a copy of the new one. The * caller still owns layout and is responsible for uninitializing it. */ int av_opt_set_chlayout(void *obj, const char *name, const AVChannelLayout *layout, int search_flags); /** * @note Any old dictionary present is discarded and replaced with a copy of the new one. The * caller still owns val is and responsible for freeing it. */ int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val, int search_flags); /** * Set a binary option to an integer list. * * @param obj AVClass object to set options on * @param name name of the binary option * @param val pointer to an integer list (must have the correct type with * regard to the contents of the list) * @param term list terminator (usually 0 or -1) * @param flags search flags */ #define av_opt_set_int_list(obj, name, val, term, flags) … /** * @} * @} */ /** * @defgroup opt_read Reading option values * @{ */ /** * @defgroup opt_get_funcs Option getting functions * @{ * Those functions get a value of the option with the given name from an object. * * @param[in] obj a struct whose first element is a pointer to an AVClass. * @param[in] name name of the option to get. * @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN * is passed here, then the option may be found in a child of obj. * @param[out] out_val value of the option will be written here * @return >=0 on success, a negative error code otherwise */ /** * @note the returned string will be av_malloc()ed and must be av_free()ed by the caller * * @note if AV_OPT_ALLOW_NULL is set in search_flags in av_opt_get, and the * option is of type AV_OPT_TYPE_STRING, AV_OPT_TYPE_BINARY or AV_OPT_TYPE_DICT * and is set to NULL, *out_val will be set to NULL instead of an allocated * empty string. */ int av_opt_get (void *obj, const char *name, int search_flags, uint8_t **out_val); int av_opt_get_int (void *obj, const char *name, int search_flags, int64_t *out_val); int av_opt_get_double (void *obj, const char *name, int search_flags, double *out_val); int av_opt_get_q (void *obj, const char *name, int search_flags, AVRational *out_val); int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out); int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt); int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt); int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val); /** * @param[out] layout The returned layout is a copy of the actual value and must * be freed with av_channel_layout_uninit() by the caller */ int av_opt_get_chlayout(void *obj, const char *name, int search_flags, AVChannelLayout *layout); /** * @param[out] out_val The returned dictionary is a copy of the actual value and must * be freed with av_dict_free() by the caller */ int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val); /** * @} */ /** * @defgroup opt_eval_funcs Evaluating option strings * @{ * This group of functions can be used to evaluate option strings * and get numbers out of them. They do the same thing as av_opt_set(), * except the result is written into the caller-supplied pointer. * * @param obj a struct whose first element is a pointer to AVClass. * @param o an option for which the string is to be evaluated. * @param val string to be evaluated. * @param *_out value of the string will be written here. * * @return 0 on success, a negative number on failure. */ int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int *flags_out); int av_opt_eval_int (void *obj, const AVOption *o, const char *val, int *int_out); int av_opt_eval_uint (void *obj, const AVOption *o, const char *val, unsigned *uint_out); int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t *int64_out); int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float *float_out); int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double *double_out); int av_opt_eval_q (void *obj, const AVOption *o, const char *val, AVRational *q_out); /** * @} */ /** * Gets a pointer to the requested field in a struct. * This function allows accessing a struct even when its fields are moved or * renamed since the application making the access has been compiled, * * @returns a pointer to the field, it can be cast to the correct type and read * or written to. */ void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name); /** * Check if given option is set to its default value. * * Options o must belong to the obj. This function must not be called to check child's options state. * @see av_opt_is_set_to_default_by_name(). * * @param obj AVClass object to check option on * @param o option to be checked * @return >0 when option is set to its default, * 0 when option is not set its default, * <0 on error */ int av_opt_is_set_to_default(void *obj, const AVOption *o); /** * Check if given option is set to its default value. * * @param obj AVClass object to check option on * @param name option name * @param search_flags combination of AV_OPT_SEARCH_* * @return >0 when option is set to its default, * 0 when option is not set its default, * <0 on error */ int av_opt_is_set_to_default_by_name(void *obj, const char *name, int search_flags); /** * Check whether a particular flag is set in a flags field. * * @param field_name the name of the flag field option * @param flag_name the name of the flag to check * @return non-zero if the flag is set, zero if the flag isn't set, * isn't of the right type, or the flags field doesn't exist. */ int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name); #define AV_OPT_SERIALIZE_SKIP_DEFAULTS … #define AV_OPT_SERIALIZE_OPT_FLAGS_EXACT … #define AV_OPT_SERIALIZE_SEARCH_CHILDREN … /** * Serialize object's options. * * Create a string containing object's serialized options. * Such string may be passed back to av_opt_set_from_string() in order to restore option values. * A key/value or pairs separator occurring in the serialized value or * name string are escaped through the av_escape() function. * * @param[in] obj AVClass object to serialize * @param[in] opt_flags serialize options with all the specified flags set (AV_OPT_FLAG) * @param[in] flags combination of AV_OPT_SERIALIZE_* flags * @param[out] buffer Pointer to buffer that will be allocated with string containg serialized options. * Buffer must be freed by the caller when is no longer needed. * @param[in] key_val_sep character used to separate key from value * @param[in] pairs_sep character used to separate two pairs from each other * @return >= 0 on success, negative on error * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same. */ int av_opt_serialize(void *obj, int opt_flags, int flags, char **buffer, const char key_val_sep, const char pairs_sep); /** * @} */ /** * Free an AVOptionRanges struct and set it to NULL. */ void av_opt_freep_ranges(AVOptionRanges **ranges); /** * Get a list of allowed ranges for the given option. * * The returned list may depend on other fields in obj like for example profile. * * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges * * The result must be freed with av_opt_freep_ranges. * * @return number of compontents returned on success, a negative errro code otherwise */ int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags); /** * Get a default list of allowed ranges for the given option. * * This list is constructed without using the AVClass.query_ranges() callback * and can be used as fallback from within the callback. * * @param flags is a bitmask of flags, undefined flags should not be set and should be ignored * AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance * AV_OPT_MULTI_COMPONENT_RANGE indicates that function may return more than one component, @see AVOptionRanges * * The result must be freed with av_opt_free_ranges. * * @return number of compontents returned on success, a negative errro code otherwise */ int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags); /** * @} */ #endif /* AVUTIL_OPT_H */
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