Option getting functions

Those functions get a value of the option with the given name from an object. More...

Functions
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)
int	av_opt_get_chlayout (void *obj, const char *name, int search_flags, AVChannelLayout *layout)
int	av_opt_get_dict_val (void *obj, const char *name, int search_flags, AVDictionary **out_val)
int	av_opt_get_array_size (void *obj, const char *name, int search_flags, unsigned int *out_val)
	For an array-type option, get the number of elements in the array.
int	av_opt_get_array (void *obj, const char *name, int search_flags, unsigned int start_elem, unsigned int nb_elems, enum AVOptionType out_type, void *out_val)
	For an array-type option, retrieve the values of one or more array elements.

Detailed Description

Those functions get a value of the option with the given name from an object.

Parameters

[in]	obj	a struct whose first element is a pointer to an AVClass.
[in]	name	name of the option to get.
[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.
[out]	out_val	value of the option will be written here

Returns

>=0 on success, a negative error code otherwise

Function Documentation

av_opt_get()

int av_opt_get	(	void *	obj,
		const char *	name,
		int	search_flags,
		uint8_t **	out_val
	)

Note

the returned string will be av_malloc()ed and must be av_free()ed by the caller

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.

av_opt_get_int()

int av_opt_get_int	(	void *	obj,
		const char *	name,
		int	search_flags,
		int64_t *	out_val
	)

av_opt_get_double()

int av_opt_get_double	(	void *	obj,
		const char *	name,
		int	search_flags,
		double *	out_val
	)

av_opt_get_q()

int av_opt_get_q	(	void *	obj,
		const char *	name,
		int	search_flags,
		AVRational *	out_val
	)

av_opt_get_image_size()

int av_opt_get_image_size	(	void *	obj,
		const char *	name,
		int	search_flags,
		int *	w_out,
		int *	h_out
	)

av_opt_get_pixel_fmt()

int av_opt_get_pixel_fmt	(	void *	obj,
		const char *	name,
		int	search_flags,
		enum AVPixelFormat *	out_fmt
	)

av_opt_get_sample_fmt()

int av_opt_get_sample_fmt	(	void *	obj,
		const char *	name,
		int	search_flags,
		enum AVSampleFormat *	out_fmt
	)

av_opt_get_video_rate()

int av_opt_get_video_rate	(	void *	obj,
		const char *	name,
		int	search_flags,
		AVRational *	out_val
	)

av_opt_get_chlayout()

int av_opt_get_chlayout	(	void *	obj,
		const char *	name,
		int	search_flags,
		AVChannelLayout *	layout
	)

Parameters

[out]

layout

The returned layout is a copy of the actual value and must be freed with av_channel_layout_uninit() by the caller

av_opt_get_dict_val()

int av_opt_get_dict_val	(	void *	obj,
		const char *	name,
		int	search_flags,
		AVDictionary **	out_val
	)

Parameters

[out]

out_val

The returned dictionary is a copy of the actual value and must be freed with av_dict_free() by the caller

av_opt_get_array_size()

int av_opt_get_array_size	(	void *	obj,
		const char *	name,
		int	search_flags,
		unsigned int *	out_val
	)

For an array-type option, get the number of elements in the array.

av_opt_get_array()

int av_opt_get_array	(	void *	obj,
		const char *	name,
		int	search_flags,
		unsigned int	start_elem,
		unsigned int	nb_elems,
		enum AVOptionType	out_type,
		void *	out_val
	)

For an array-type option, retrieve the values of one or more array elements.

Parameters

start_elem	index of the first array element to retrieve
nb_elems	number of array elements to retrieve; start_elem+nb_elems must not be larger than array size as returned by av_opt_get_array_size()
out_type	Option type corresponding to the desired output. The array elements produced by this function will will be as if av_opt_getX() was called for each element, where X is specified by out_type. E.g. AV_OPT_TYPE_STRING corresponds to av_opt_get(). Typically this should be the same as the scalarized type of the AVOption being retrieved, but certain conversions are also possible - the same as those done by the corresponding av_opt_get*() function. E.g. any option type can be retrieved as a string, numeric types can be retrieved as int64, double, or rational, etc.
out_val	Array with nb_elems members into which the output will be written. The array type must match the underlying C type as documented for out_type, and be zeroed on entry to this function.

For dynamically allocated types (strings, binary, dicts, etc.), the result is owned and freed by the caller.