gain_map.h File Reference

#include <stddef.h>
#include "rational.h"
#include "frame.h"

Go to the source code of this file.

Data Structures
struct	AVGainMapParams
	Parameters describing how to combine a gain map rendition with its base rendition to recover the alternate rendition, as defined by ISO 21496-1:2025 "Digital photography - Gain map metadata for image conversion". More...
struct	AVGainMapParams::AVGainMapChannel

Macros
#define	AV_ISO21496_VERSION   0
#define	AV_ISO21496_IDENTIFIER   "urn:iso:std:iso:ts:21496:-1"

Functions
int	av_gain_map_params_validate (const AVGainMapParams *p)
	Returns >= 0 if the given AVGainMapParams struct contains valid data; or a negative AVERROR otherwise.
int	av_gain_map_channels_identical (const AVGainMapParams *p)
	Returns 1 if all channels of the gain map have identical parameters, 0 otherwise.
AVGainMapParams *	av_gain_map_params_alloc (size_t *size)
	Allocate an AVGainMapParams structure and initialize it to default values.
AVGainMapParams *	av_gain_map_params_create_side_data (AVFrameSideData ***sd, int *nb_sd)
	Allocate and add an AVGainMapParams structure to an existing AVFrameSideData array as AV_FRAME_DATA_GAIN_MAP_PARAMS side data.

Macro Definition Documentation

AV_ISO21496_VERSION

#define AV_ISO21496_VERSION   0

Definition at line 27 of file gain_map.h.

Referenced by av_gain_map_params_validate().

AV_ISO21496_IDENTIFIER

#define AV_ISO21496_IDENTIFIER   "urn:iso:std:iso:ts:21496:-1"

Definition at line 28 of file gain_map.h.

Referenced by ff_mjpeg_add_gain_map_size(), jpeg_put_comments(), mpf_write_iso21496(), and parse_app2().

Function Documentation

av_gain_map_params_validate()

int av_gain_map_params_validate

(

const AVGainMapParams *

p

)

Returns >= 0 if the given AVGainMapParams struct contains valid data; or a negative AVERROR otherwise.

Note: The ISO spec declares these as signed, but a negative value makes no numeric sense and would result in infinities in the middle of the valid signal range; so just constrain them to be unsigned as a safeguard. Note that the Adobe hdrgm spec explicitly requires them to be nonnegative as well, so this avoids an inconsistency.

Definition at line 46 of file gain_map.c.

Referenced by ff_gain_map_params_check_xmp(), ff_gain_map_params_from_iso21496(), ff_gain_map_params_to_iso21496(), ff_mjpeg_add_gain_map_size(), and process_frame().

av_gain_map_channels_identical()

int av_gain_map_channels_identical

(

const AVGainMapParams *

p

)

Returns 1 if all channels of the gain map have identical parameters, 0 otherwise.

Definition at line 75 of file gain_map.c.

Referenced by ff_gain_map_params_check_xmp(), and ff_gain_map_params_to_iso21496().

av_gain_map_params_alloc()

AVGainMapParams * av_gain_map_params_alloc

(

size_t *

size

)

Allocate an AVGainMapParams structure and initialize it to default values.

The resulting pointer must be freed using av_free().

Parameters

size	if non-NULL, set to sizeof(AVGainMapParams)

Returns

the newly allocated struct, or NULL on failure

Definition at line 84 of file gain_map.c.

av_gain_map_params_create_side_data()

AVGainMapParams * av_gain_map_params_create_side_data	(	AVFrameSideData ***	sd,
		int *	nb_sd )

Allocate and add an AVGainMapParams structure to an existing AVFrameSideData array as AV_FRAME_DATA_GAIN_MAP_PARAMS side data.

Returns

the newly allocated struct, or NULL on failure

Definition at line 98 of file gain_map.c.

Referenced by process_frame().