PHP exif_read_data function

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exif_read_data

(PHP 4 >= 4.2.0, PHP 5)

exif_read_data — Reads the EXIF headers from JPEG or TIFFDescriptionarray exif_read_data ( string filename [, string sections [, bool arrays [, bool thumbnail]]] )

exif_read_data() reads the
EXIF headers from a JPEG or
TIFF image file. This way you can read meta data
generated by digital cameras.

Exif headers tend to be present in JPEG/TIFF images generated by digital
cameras, but unfortunately each digital camera maker has a different
idea of how to actually tag their images, so you can’t always rely on
a specific Exif header being present.

Height and Width are computed the
same way getimagesize() does so their values must not be
part of any header returned. Also, html is a
height/width text string to be used inside normal HTML.

When an Exif header contains a Copyright note, this itself can contain two
values. As the solution is inconsistent in the Exif 2.10 standard, the COMPUTED
section will return both entries Copyright.Photographer
and Copyright.Editor while the IFD0 sections contains
the byte array with the NULL character that splits both entries. Or just the
first entry if the datatype was wrong (normal behaviour of Exif). The
COMPUTED will also contain the entry Copyright which
is either the original copyright string, or a comma separated list of the
photo and editor copyright.

The tag UserComment has the same problem as the Copyright tag. It can store
two values. First the encoding used, and second the value itself. If so the
IFD section only contains the encoding or a byte array. The COMPUTED section
will store both in the entries UserCommentEncoding and
UserComment. The entry UserComment
is available in both cases so it should be used in preference to the value
in IFD0 section.

exif_read_data() also validates EXIF data tags according
to the EXIF specification (http://exif.org/Exif2-2.PDF, page 20).

Note:
Windows ME/XP can both wipe the Exif headers when connecting to a camera.
More information available at http://www.canon.co.jp/Imaging/NOTICE/011214-e.html.

Parameters

filename

The name of the image file being read. This cannot be an
URL.

sections

Is a comma separated list of sections that need to be present in file
to produce a result array. If none of the requested
sections could be found the return value is FALSE.

FILEFileName, FileSize, FileDateTime, SectionsFoundCOMPUTED html, Width, Height, IsColor, and more if available. Height and
Width are computed the same way getimagesize()
does so their values must not be part of any header returned.
Also, html is a height/width text string to be used inside normal
HTML.
ANY_TAGAny information that has a Tag e.g. IFD0, EXIF, …IFD0 All tagged data of IFD0. In normal imagefiles this contains
image size and so forth.
THUMBNAIL A file is supposed to contain a thumbnail if it has a second IFD.
All tagged information about the embedded thumbnail is stored in
this section.
COMMENTComment headers of JPEG images.EXIF The EXIF section is a sub section of IFD0. It contains
more detailed information about an image. Most of these entries
are digital camera related.

arrays

Specifies whether or not each section becomes an array. The
sections COMPUTED,
THUMBNAIL, and COMMENT
always become arrays as they may contain values whose names conflict
with other sections.

thumbnail

When set to TRUE the thumbnail itself is read. Otherwise, only the
tagged data is read.

Return Values

It returns an associative array where the array indexes are
the header names and the array values are the values associated with
those headers. If no data can be returned,
exif_read_data() will return FALSE.

ChangeLog

VersionDescription4.3.0 Can read all embedded IFD data including arrays
(returned as such). Also the size of an embedded thumbnail is
returned in a THUMBNAIL subarray, and can
return thumbnails in TIFF format. Also, there is
no longer a maximum length for returned values (not until the memory
limit has been reached)
4.3.0 If PHP has mbstring support,
the user comment can automatically change encoding. Also, if the
user comment uses Unicode or JIS encoding this encoding will
automatically be changed according to the exif ini settings in
php.ini
4.3.0 If the image contains any IFD0 data then COMPUTED contains the entry
ByteOrderMotorola which is 0 for little-endian (intel) and 1 for
big-endian (motorola) byte order. Also, COMPUTED and UserComment no
longer only contain the first copyright entry if the datatype was
wrong.

Examples

Example 1. exif_read_data() example

The first call fails because the image has no header information.

The above example will output
something similar to:

test1.jpg:
No header data found.
test2.jpg:
FILE.FileName: test2.jpg
FILE.FileDateTime: 1017666176
FILE.FileSize: 1240
FILE.FileType: 2
FILE.SectionsFound: ANY_TAG, IFD0, THUMBNAIL, COMMENT
COMPUTED.html: width=”1″ height=”1″
COMPUTED.Height: 1
COMPUTED.Width: 1
COMPUTED.IsColor: 1
COMPUTED.ByteOrderMotorola: 1
COMPUTED.UserComment: Exif test image.
COMPUTED.UserCommentEncoding: ASCII
COMPUTED.Copyright: Photo (c) M.Boerger, Edited by M.Boerger.
COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
COMPUTED.Copyright.Editor: Edited by M.Boerger.
IFD0.Copyright: Photo (c) M.Boerger
IFD0.UserComment: ASCII
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.JPEGInterchangeFormatLength: 523
COMMENT.0: Comment #1.
COMMENT.1: Comment #2.
COMMENT.2: Comment #3end
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.Thumbnail.Height: 1
THUMBNAIL.Thumbnail.Height: 1

See Also

exif_thumbnail()getimagesize()