(*
* AVOptions
* copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* This is a part of Pascal porting of ffmpeg.
* - Originally by Victor Zinetz for Delphi and Free Pascal on Windows.
* - For Mac OS X, some modifications were made by The Creative CAT, denoted as CAT
* in the source codes.
* - Changes and updates by the UltraStar Deluxe Team
*
* Conversion of libavutil/opt.h
* avutil version 51.32.0
*
*)
(**
* @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.
*
* @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 must 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 {
* AVClass *class;
* int int_opt;
* char *str_opt;
* uint8_t *bin_opt;
* int bin_len;
* } test_struct;
*
* static const AVOption options[] = {
* { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
* AV_OPT_TYPE_INT, { -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 = 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() must 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_malloc(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_next() 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, { 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_next(const AVClass *prev)
* {
* return prev ? NULL : &child_class;
* }
* @endcode
* Putting child_next() and child_class_next() 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_next() are needed. The distinction is that child_next()
* iterates over actually existing objects, while child_class_next()
* 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_next() 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 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, { 0 }, INT_MIN, INT_MAX, "test_unit" },
* { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { 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_next() 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 allows 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.
*)
type
TAVOptionType = (
{$IFDEF FF_API_OLD_AVOPTIONS}
FF_OPT_TYPE_FLAGS = 0,
FF_OPT_TYPE_INT,
FF_OPT_TYPE_INT64,
FF_OPT_TYPE_DOUBLE,
FF_OPT_TYPE_FLOAT,
FF_OPT_TYPE_STRING,
FF_OPT_TYPE_RATIONAL,
FF_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
FF_OPT_TYPE_CONST = 128
{$ELSE}
AV_OPT_TYPE_FLAGS,
AV_OPT_TYPE_INT,
AV_OPT_TYPE_INT64,
AV_OPT_TYPE_DOUBLE,
AV_OPT_TYPE_FLOAT,
AV_OPT_TYPE_STRING,
AV_OPT_TYPE_RATIONAL,
AV_OPT_TYPE_BINARY, ///< offset must point to a pointer immediately followed by an int for the length
AV_OPT_TYPE_CONST = 128
{$ENDIF}
);
const
AV_OPT_FLAG_ENCODING_PARAM = 1; ///< a generic parameter which can be set by the user for muxing or encoding
AV_OPT_FLAG_DECODING_PARAM = 2; ///< a generic parameter which can be set by the user for demuxing or decoding
AV_OPT_FLAG_METADATA = 4; ///< some data extracted or inserted into the file like title, comment, ...
AV_OPT_FLAG_AUDIO_PARAM = 8;
AV_OPT_FLAG_VIDEO_PARAM = 16;
AV_OPT_FLAG_SUBTITLE_PARAM = 32;
type
(**
* AVOption
*)
PAVOption = ^TAVOption;
TAVOption = record
name: {const} PAnsiChar;
(**
* short English help text
* @todo What about other languages?
*)
help: {const} PAnsiChar;
(**
* The offset relative to the context structure where the option
* value is stored. It should be 0 for named constants.
*)
offset: cint;
type_: TAVOptionType;
(**
* the default value for scalar options
*)
default_val: record
case cint of
0: (dbl: cdouble);
1: (str: {const} PAnsiChar);
(* TODO those are unused now *)
2: (i64: cint64);
3: (q: TAVRational);
end;
min: cdouble; ///< minimum valid value for the option
max: cdouble; ///< maximum valid value for the option
flags: cint;
//FIXME think about enc-audio, ... style flags
(**
* The logical unit to which the option belongs. Non-constant
* options and corresponding named constants share the same
* unit. May be NULL.
*)
unit_: {const} PAnsiChar;
end;
{$IFDEF FF_API_FIND_OPT}
(**
* Look for an option in obj. Look only for the options which
* have the flags set as specified in mask and 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
*)
function av_find_opt(obj: Pointer; {const} name: {const} PAnsiChar; {const} unit_: PAnsiChar; mask: cint; flags: cint): {const} PAVOption;
cdecl; external av__util; deprecated;
{$ENDIF}
{$IFDEF FF_API_OLD_AVOPTIONS}
(**
* 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. 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, or an AVERROR code in case of
* error:
* AVERROR(ENOENT) if no matching option exists
* AVERROR(ERANGE) if the value is out of range
* AVERROR(EINVAL) if the value is not valid
*)
function av_set_string3(obj: Pointer; name: {const} PAnsiChar; val: {const} PAnsiChar; alloc: cint; out o_out: {const} PAVOption): cint;
cdecl; external av__util; deprecated;
function av_set_double(obj: pointer; name: {const} PAnsiChar; n: cdouble): PAVOption;
cdecl; external av__util; deprecated;
function av_set_q(obj: pointer; name: {const} PAnsiChar; n: TAVRational): PAVOption;
cdecl; external av__util; deprecated;
function av_set_int(obj: pointer; name: {const} PAnsiChar; n: cint64): PAVOption;
cdecl; external av__util; deprecated;
function av_get_double(obj: pointer; name: {const} PAnsiChar; var o_out: {const} PAVOption): cdouble;
cdecl; external av__util;
function av_get_q(obj: pointer; name: {const} PAnsiChar; var o_out: {const} PAVOption): TAVRational;
cdecl; external av__util;
function av_get_int(obj: pointer; name: {const} PAnsiChar; var o_out: {const} PAVOption): cint64;
cdecl; external av__util;
function av_get_string(obj: pointer; name: {const} PAnsiChar; var o_out: {const} PAVOption; buf: PAnsiChar; buf_len: cint): PAnsiChar;
cdecl; external av__util; deprecated;
function av_next_option(obj: pointer; last: {const} PAVOption): PAVOption;
cdecl; external av__util; deprecated;
{$ENDIF}
(**
* Show the obj options.
*
* @param req_flags requested flags for the options to show. Show only the
* options for which it is opt->flags & req_flags.
* @param rej_flags rejected flags for the options to show. Show only the
* options for which it is !(opt->flags & req_flags).
* @param av_log_obj log context to use for showing the options
*)
function av_opt_show2(obj: pointer; av_log_obj: pointer; req_flags: cint; rej_flags: cint): cint;
cdecl; external av__util;
(**
* Set the values of all AVOption fields to their default values.
*
* @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)
*)
procedure av_opt_set_defaults(s: pointer);
cdecl; external av__util;
{$IFDEF FF_API_OLD_AVOPTIONS}
procedure av_opt_set_defaults2(s: Pointer; mask: cint; flags: cint);
cdecl; external av__util; deprecated;
{$ENDIF}
(**
* 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_set_string3() if a key/value pair
* cannot be set
*)
function av_set_options_string(ctx: pointer; opts: {const} PAnsiChar;
key_val_sep: {const} PAnsiChar; pairs_sep: {const} PAnsiChar): cint;
cdecl; external av__util;
(**
* Free all string and binary options in obj.
*)
procedure av_opt_free(obj: pointer);
cdecl; external av__util;
(**
* 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.
*)
function av_opt_flag_is_set(obj: pointer; field_name: {const} PAnsiChar; flag_name: {const} PAnsiChar): cint;
cdecl; external av__util;
(**
* 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()
*)
function av_opt_set_dict(obj: pointer; var options: PAVDictionary): cint;
cdecl; external av__util;
(**
* @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.
*)
function av_opt_eval_flags (obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; flags_out: Pcint): cint;
cdecl; external av__util;
function av_opt_eval_int (obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; int_out: Pcint): cint;
cdecl; external av__util;
function av_opt_eval_int64 (obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; int64_out: Pcint64): cint;
cdecl; external av__util;
function av_opt_eval_float (obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; float_out: Pcfloat): cint;
cdecl; external av__util;
function av_opt_eval_double(obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; double_out: Pcdouble): cint;
cdecl; external av__util;
function av_opt_eval_q (obj: pointer; o: {const} PAVOption; val: {const} PAnsiChar; q_out: PAVRational): cint;
cdecl; external av__util;
const
AV_OPT_SEARCH_CHILDREN = 0001; (**< Search in possible children of the
given object first.*)
(**
* 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.
*)
AV_OPT_SEARCH_FAKE_OBJ = 0002;
(**
* 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.
* @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_set_string3(). Use special calls which take an options
* AVDictionary (e.g. avformat_open_input()) to set options found with this
* flag.
*)
function av_opt_find(obj: pointer; name: {const} PAnsiChar; unit_: {const} PAnsiChar;
opt_flags: cint; search_flags: cint): PAVOption;
cdecl; external av__util;
(**
* 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.
*)
function av_opt_find2(obj: pointer; name: {const} PAnsiChar; unit_: {const} PAnsiChar;
opt_flags: cint; search_flags: cint; target_obj: pointer): {const} PAVOption;
cdecl; external av__util;
(**
* 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
*)
function av_opt_next(obj: pointer; prev: {const} PAVOption): {const} PAVOption;
cdecl; external av__util;
(**
* 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
*)
function av_opt_child_next(obj: pointer; prev: pointer): pointer;
cdecl; external av__util;
