#include <stddef.h>#include <stdint.h>#include "libavutil/buffer.h"#include "libavutil/dict.h"#include "libavutil/rational.h"#include "version_major.h"Go to the source code of this file.
EXIF metadata parser
Definition in file exif.h.
| 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 "Exif0円0円", then it's AV_EXIF_TIFF_HEADER. |
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().
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_attach_sidedata(), libjxl_preprocess_stream(), mov_parse_exif_item(), and side_data_exif_parse().
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 1059 of file exif.c.
Referenced by ff_exif_sanitize_ifd().
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 1054 of file exif.c.
Referenced by av_exif_set_entry(), ff_exif_sanitize_ifd(), libjxl_preprocess_stream(), and side_data_exif_parse().
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 1143 of file exif.c.
Referenced by exif_attach_ifd(), libjxl_attach_sidedata(), libjxl_preprocess_stream(), mov_parse_exif_item(), and side_data_exif_parse().
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 767 of file exif.c.
Referenced by avi_extract_stream_metadata(), decode_frame(), ff_decode_exif_attach_buffer(), ff_exif_get_buffer(), libjxl_attach_sidedata(), libjxl_preprocess_stream(), mjpeg_decode_app(), mov_parse_exif_item(), and side_data_exif_parse().
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 706 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().
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 612 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_attach_sidedata(), libjxl_preprocess_stream(), mov_parse_exif_item(), side_data_exif_parse(), and tiff_end().
Recursively reads all tags from the IFD and stores them in the provided metadata dictionary.
Definition at line 917 of file exif.c.
Referenced by avi_extract_stream_metadata(), avpriv_exif_decode_ifd(), exif_attach_ifd(), and side_data_exif_parse().
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 1148 of file exif.c.
Referenced by exif_attach_ifd(), and exif_clone_entry().
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 1184 of file exif.c.
Referenced by encode_frame(), ff_exif_sanitize_ifd(), and libjxl_preprocess_stream().
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 1197 of file exif.c.
Referenced by attach_displaymatrix(), libjxl_preprocess_stream(), and side_data_exif_parse().