#include <stddef.h>
#include <stdint.h>
#include "libavutil/buffer.h"
#include "libavutil/dict.h"
#include "libavutil/rational.h"
#include "version_major.h"

Data Structures
struct	AVExifMetadata

struct	AVExifEntry

Macros
#define	AV_EXIF_FLAG_RECURSIVE (1 << 0)
	Also check subdirectories. More...

Enumerations
enum	AVTiffDataType { AV_TIFF_BYTE = 1, AV_TIFF_STRING, AV_TIFF_SHORT, AV_TIFF_LONG, AV_TIFF_RATIONAL, AV_TIFF_SBYTE, AV_TIFF_UNDEFINED, AV_TIFF_SSHORT, AV_TIFF_SLONG, AV_TIFF_SRATIONAL, AV_TIFF_FLOAT, AV_TIFF_DOUBLE, AV_TIFF_IFD }
	Data type identifiers for TIFF tags. More...

enum	AVExifHeaderMode { AV_EXIF_TIFF_HEADER, AV_EXIF_ASSUME_LE, AV_EXIF_ASSUME_BE, AV_EXIF_T_OFF, AV_EXIF_EXIF00 }

Functions
const char *	av_exif_get_tag_name (uint16_t id)
	Retrieves the tag name associated with the provided tag ID. More...

int32_t	av_exif_get_tag_id (const char *name)
	Retrieves the tag ID associated with the provided tag string name. More...

int	av_exif_set_entry (void logctx, AVExifMetadata ifd, uint16_t id, enum AVTiffDataType type, uint32_t count, const uint8_t ifd_lead, uint32_t ifd_offset, const void value)
	Add an entry to the provided EXIF metadata struct. More...

int	av_exif_get_entry (void logctx, AVExifMetadata ifd, uint16_t id, int flags, AVExifEntry **value)
	Get an entry with the tagged ID from the EXIF metadata struct. More...

int	av_exif_remove_entry (void logctx, AVExifMetadata ifd, uint16_t id, int flags)
	Remove an entry from the provided EXIF metadata struct. More...

int	av_exif_parse_buffer (void logctx, const uint8_t data, size_t size, AVExifMetadata *ifd, enum AVExifHeaderMode header_mode)
	Decodes the EXIF data provided in the buffer and writes it into the struct *ifd. More...

int	av_exif_write (void logctx, const AVExifMetadata ifd, AVBufferRef **buffer, enum AVExifHeaderMode header_mode)
	Allocates a buffer using av_malloc of an appropriate size and writes the EXIF data represented by ifd into that buffer. More...

void	av_exif_free (AVExifMetadata *ifd)
	Frees all resources associated with the given EXIF metadata struct. More...

int	av_exif_ifd_to_dict (void logctx, const AVExifMetadata ifd, AVDictionary **metadata)
	Recursively reads all tags from the IFD and stores them in the provided metadata dictionary. More...

AVExifMetadata *	av_exif_clone_ifd (const AVExifMetadata *ifd)
	Allocates a duplicate of the provided EXIF metadata struct. More...

int	av_exif_matrix_to_orientation (const int32_t *matrix)
	Convert a display matrix used by AV_FRAME_DATA_DISPLAYMATRIX into an orientation constant used by EXIF's orientation tag. More...

int	av_exif_orientation_to_matrix (int32_t *matrix, int orientation)
	Convert an orientation constant used by EXIF's orientation tag into a display matrix used by AV_FRAME_DATA_DISPLAYMATRIX. More...

Detailed Description

EXIF metadata parser

Author: Thilo Borgmann <thilo.borgmann at mail.de>; Leo Izen leo.i.nosp@m.zen@.nosp@m.gmail.nosp@m..com

Definition in file exif.h.

Macro Definition Documentation

◆ AV_EXIF_FLAG_RECURSIVE

#define AV_EXIF_FLAG_RECURSIVE (1 << 0)

Also check subdirectories.

Definition at line 150 of file exif.h.

Enumeration Type Documentation

◆ AVTiffDataType

enum AVTiffDataType

Data type identifiers for TIFF tags.

Enumerator
AV_TIFF_BYTE
AV_TIFF_STRING
AV_TIFF_SHORT
AV_TIFF_LONG
AV_TIFF_RATIONAL
AV_TIFF_SBYTE
AV_TIFF_UNDEFINED
AV_TIFF_SSHORT
AV_TIFF_SLONG
AV_TIFF_SRATIONAL
AV_TIFF_FLOAT
AV_TIFF_DOUBLE
AV_TIFF_IFD

Definition at line 42 of file exif.h.

◆ AVExifHeaderMode

enum AVExifHeaderMode

Enumerator
AV_EXIF_TIFF_HEADER	The TIFF header starts with 0x49492a00, or 0x4d4d002a. This one is used internally by FFmpeg.
AV_EXIF_ASSUME_LE	skip the TIFF header, assume little endian
AV_EXIF_ASSUME_BE	skip the TIFF header, assume big endian
AV_EXIF_T_OFF	The first four bytes point to the actual start, then it's AV_EXIF_TIFF_HEADER.
AV_EXIF_EXIF00	The first six bytes contain "Exif\0\0", then it's AV_EXIF_TIFF_HEADER.

Definition at line 58 of file exif.h.

Function Documentation

◆ av_exif_get_tag_name()

const char* av_exif_get_tag_name ( uint16_t id )

Retrieves the tag name associated with the provided tag ID.

If the tag ID is unknown, NULL is returned.

For example, av_exif_get_tag_name(0x112) returns "Orientation".

Definition at line 215 of file exif.c.

Referenced by exif_ifd_to_dict().

◆ av_exif_get_tag_id()

int32_t av_exif_get_tag_id ( const char * name )

Retrieves the tag ID associated with the provided tag string name.

If the tag name is unknown, a negative number is returned. Otherwise it always fits inside a uint16_t integer.

For example, av_exif_get_tag_id("Orientation") returns 274 (0x0112).

Definition at line 225 of file exif.c.

Referenced by exif_attach_ifd(), libjxl_preprocess_stream(), libjxl_receive_frame(), mov_parse_exif_item(), and side_data_exif_parse().

◆ av_exif_set_entry()

int av_exif_set_entry	(	void *	logctx,
		AVExifMetadata *	ifd,
		uint16_t	id,
		enum AVTiffDataType	type,
		uint32_t	count,
		const uint8_t *	ifd_lead,
		uint32_t	ifd_offset,
		const void *	value
	)

Add an entry to the provided EXIF metadata struct.

If one already exists with the provided ID, it will set the existing one to have the other information provided. Otherwise, it will allocate a new entry.

This function reallocates ifd->entries using av_realloc and allocates (using av_malloc) a new value member of the entry, then copies the contents of value into that buffer.

Definition at line 1054 of file exif.c.

Referenced by ff_exif_sanitize_ifd().

◆ av_exif_get_entry()

int av_exif_get_entry	(	void *	logctx,
		AVExifMetadata *	ifd,
		uint16_t	id,
		int	flags,
		AVExifEntry **	value
	)

Get an entry with the tagged ID from the EXIF metadata struct.

A pointer to the entry will be written into *value.

If the entry was present and returned successfully, a positive number is returned. If the entry was not found, *value is left untouched and zero is returned. If an error occurred, a negative number is returned.

Definition at line 1049 of file exif.c.

Referenced by av_exif_set_entry(), ff_exif_sanitize_ifd(), libjxl_preprocess_stream(), and side_data_exif_parse().

◆ av_exif_remove_entry()

int av_exif_remove_entry	(	void *	logctx,
		AVExifMetadata *	ifd,
		uint16_t	id,
		int	flags
	)

Remove an entry from the provided EXIF metadata struct.

If the entry was present and removed successfully, a positive number is returned. If the entry was not found, zero is returned. If an error occurred, a negative number is returned.

Definition at line 1138 of file exif.c.

Referenced by exif_attach_ifd(), libjxl_preprocess_stream(), libjxl_receive_frame(), mov_parse_exif_item(), and side_data_exif_parse().

◆ av_exif_parse_buffer()

int av_exif_parse_buffer	(	void *	logctx,
		const uint8_t *	data,
		size_t	size,
		AVExifMetadata *	ifd,
		enum AVExifHeaderMode	header_mode
	)

Decodes the EXIF data provided in the buffer and writes it into the struct *ifd.

If this function succeeds, the IFD is owned by the caller and must be cleared after use by calling av_exif_free(); If this function fails and returns a negative value, it will call av_exif_free(ifd) before returning.

Definition at line 764 of file exif.c.

Referenced by avi_extract_stream_metadata(), decode_frame(), ff_decode_exif_attach_buffer(), ff_exif_get_buffer(), libjxl_preprocess_stream(), libjxl_receive_frame(), mjpeg_decode_app(), mov_parse_exif_item(), and side_data_exif_parse().

◆ av_exif_write()

int av_exif_write	(	void *	logctx,
		const AVExifMetadata *	ifd,
		AVBufferRef **	buffer,
		enum AVExifHeaderMode	header_mode
	)

Allocates a buffer using av_malloc of an appropriate size and writes the EXIF data represented by ifd into that buffer.

Upon error, *buffer will be NULL. The buffer becomes owned by the caller upon success. The *buffer argument must be NULL before calling.

Definition at line 703 of file exif.c.

Referenced by exif_attach_ifd(), ff_exif_get_buffer(), libjxl_preprocess_stream(), mov_parse_exif_item(), and side_data_exif_parse().

◆ av_exif_free()

void av_exif_free ( AVExifMetadata * ifd )

Frees all resources associated with the given EXIF metadata struct.

Does not free the pointer passed itself, in case it is stack-allocated. The pointer passed to this function must be freed by the caller, if it is heap-allocated. Passing NULL is permitted.

Definition at line 609 of file exif.c.

Referenced by av_exif_clone_ifd(), av_exif_parse_buffer(), avi_extract_stream_metadata(), avpriv_exif_decode_ifd(), decode_frame(), exif_attach_ifd(), exif_clone_entry(), exif_decode_tag(), exif_free_entry(), ff_decode_exif_attach_buffer(), ff_exif_get_buffer(), ff_exif_sanitize_ifd(), ff_mjpeg_decode_end(), ff_mjpeg_decode_frame_from_buf(), libjxl_preprocess_stream(), libjxl_receive_frame(), mov_parse_exif_item(), side_data_exif_parse(), and tiff_end().

◆ av_exif_ifd_to_dict()

int av_exif_ifd_to_dict	(	void *	logctx,
		const AVExifMetadata *	ifd,
		AVDictionary **	metadata
	)

Recursively reads all tags from the IFD and stores them in the provided metadata dictionary.

Definition at line 914 of file exif.c.

Referenced by avi_extract_stream_metadata(), avpriv_exif_decode_ifd(), exif_attach_ifd(), and side_data_exif_parse().

◆ av_exif_clone_ifd()

AVExifMetadata* av_exif_clone_ifd ( const AVExifMetadata * ifd )

Allocates a duplicate of the provided EXIF metadata struct.

The caller owns the duplicate and must free it with av_exif_free. Returns NULL if the duplication process failed.

Definition at line 1143 of file exif.c.

Referenced by exif_attach_ifd(), and exif_clone_entry().

◆ av_exif_matrix_to_orientation()

int av_exif_matrix_to_orientation ( const int32_t * matrix )

Convert a display matrix used by AV_FRAME_DATA_DISPLAYMATRIX into an orientation constant used by EXIF's orientation tag.

Returns an EXIF orientation between 1 and 8 (inclusive) depending on the rotation and flip factors. Returns 0 if the matrix is singular.

Definition at line 1179 of file exif.c.

Referenced by ff_exif_sanitize_ifd(), and libjxl_preprocess_stream().

◆ av_exif_orientation_to_matrix()

int av_exif_orientation_to_matrix	(	int32_t *	matrix,
		int	orientation
	)

Convert an orientation constant used by EXIF's orientation tag into a display matrix used by AV_FRAME_DATA_DISPLAYMATRIX.

Returns 0 on success and negative if the orientation is invalid, i.e. not between 1 and 8 (inclusive).

Definition at line 1192 of file exif.c.

Referenced by attach_displaymatrix(), libjxl_preprocess_stream(), and side_data_exif_parse().

Data Structures

Macros

Enumerations

Functions