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Image::ExifTool(3pm) User Contributed Perl Documentation Image::ExifTool(3pm)

NAME
Image::ExifTool - Read and write meta information

SYNOPSIS
use Image::ExifTool qw(:Public);

# ---- Simple procedural usage ----

# Get hash of meta information tag names/values from an image
$info = ImageInfo('a.jpg');

# ---- Object-oriented usage ----

# Create a new Image::ExifTool object
$exifTool = Image::ExifTool->new;

# Extract meta information from an image
$exifTool->ExtractInfo($file, \%options);

# Get list of tags in the order they were found in the file
@tagList = $exifTool->GetFoundTags('File');

# Get the value of a specified tag
$value = $exifTool->GetValue($tag, $type);

# Get a tag description
$description = $exifTool->GetDescription($tag);

# Get the group name associated with this tag
$group = $exifTool->GetGroup($tag, $family);

# Set a new value for a tag
$exifTool->SetNewValue($tag, $newValue);

# Write new meta information to a file
$success = $exifTool->WriteInfo($srcfile, $dstfile);

# ...plus a host of other useful methods...

DESCRIPTION
Reads and writes meta information in a wide variety of files, including
the maker notes of many digital cameras by various manufacturers such as
Canon, Casio, DJI, FLIR, FujiFilm, GE, GoPro, HP, JVC/Victor, Kodak,
Leaf, Minolta/Konica-Minolta, Nikon, Nintendo, Olympus/Epson,
Panasonic/Leica, Pentax/Asahi, Phase One, Reconyx, Ricoh, Samsung,
Sanyo, Sigma/Foveon and Sony.

Below is a list of file types and meta information formats currently
supported by ExifTool (r = read, w = write, c = create):

CONFIGURATION
User-defined tags can be added via the ExifTool configuration file, or
by defining the %Image::ExifTool::UserDefined hash before calling any
ExifTool methods. See "ExifTool_config" in the ExifTool distribution
for more details.

By default ExifTool looks for a configuration file named
".ExifTool_config" first in your home directory, then in the directory
of the application script, but a different directory may be specified by
setting the EXIFTOOL_HOME environment variable, or a different file may
be specified by setting the ExifTool "configFile" variable before using
Image::ExifTool. For example:

BEGIN { $Image::ExifTool::configFile = '/Users/phil/myconfig.cfg' }
use Image::ExifTool;

The configuration feature may also be disabled by setting "configFile"
to an empty string:

BEGIN { $Image::ExifTool::configFile = '' }
use Image::ExifTool;

EXPORTS
Exports nothing by default, but "ImageInfo" and all static methods may
be exported with the ":Public" export list.

METHODS
All ExifTool features are accessed through the methods of the public
interface listed below. Other Image::ExifTool methods and modules
should not be accessed directly because their interface may change with
future versions.

None of these methods should ever die or issue warnings to STDERR if
called with the proper arguments (with the exception of "SetNewValue"
which may send an error message to STDERR, but only when called in
scalar context). Error and warning messages that occur during
processing are stored in the values of the Error and Warning tags, and
are accessible via the "GetValue" method to retrieve a single Error or
Warning message, or "GetInfo" to retrieve any number of them.

The ExifTool methods are not thread safe.

new
Creates a new ExifTool object.

$exifTool = Image::ExifTool->new;

One ExifTool object may be used to process many files, so creating
multiple ExifTool objects usually is not necessary.

Note that ExifTool uses AUTOLOAD to load non-member methods, so any
class using Image::ExifTool as a base class must define an AUTOLOAD
which calls Image::ExifTool::DoAutoLoad(). eg)

sub AUTOLOAD
{
Image::ExifTool::DoAutoLoad($AUTOLOAD, @_);
}

ImageInfo
Read image file and return meta information. This is the one step
function for retrieving meta information from an image. Internally,
"ImageInfo" calls "ExtractInfo" to extract the information, "GetInfo" to
generate the information hash, and "GetTagList" for the returned tag
list.

# return meta information for 2 tags only (procedural)
$info = ImageInfo($filename, $tag1, $tag2);

# return information about an open image file (object-oriented)
$info = $exifTool->ImageInfo(\*FILE);

# return information from image data in memory for specified tags
%options = (PrintConv => 0);
@tagList = qw(filename imagesize xmp:creator exif:* -ifd1:*);
$info = ImageInfo(\$imageData, \@tagList, \%options);

# extract information from an embedded thumbnail image
$info = ImageInfo('image.jpg', 'thumbnailimage');
$thumbInfo = ImageInfo($$info{ThumbnailImage});

Inputs:
"ImageInfo" is very flexible about the input arguments, and
interprets them based on their type. It may be called with one or
more arguments. The one required argument is either a SCALAR (the
image file name), a file reference (a reference to the image file)
or a SCALAR reference (a reference to the image in memory). Other
arguments are optional. The order of the arguments is not
significant, except that the first SCALAR is taken to be the file
name unless a file reference or scalar reference comes earlier in
the argument list.

Below is an explanation of how the "ImageInfo" function arguments
are interpreted:

ExifTool ref
"ImageInfo" may be called with an ExifTool object if desired.
Advantages of using the object-oriented form are that options
may be set before calling "ImageInfo", and the object may be
used afterward to access member functions. Must be the first
argument if used.

SCALAR
The first scalar argument is taken to be the file name unless an
earlier argument specified the image data via a file reference
(file ref) or data reference (SCALAR ref). The remaining scalar
arguments are names of tags for requested information. All tags
are returned if no tags are specified.

Tag names are case-insensitive and may be prefixed by optional
group names separated by colons. A group name may begin with a
family number (eg. '1IPTC:Keywords'), to restrict matches to a
specific family. In the tag name, a '?' matches any single
character and a '*' matches zero or more characters. Thus
'GROUP:*' represents all tags in a specific group. Wildcards
may not be used in group names, with the exception that a group
name of '*' may be used to extract all available instances of a
tag regardless of the "Duplicates" setting (eg.
'*:WhiteBalance'). Multiple groups may be specified (eg.
'EXIF:Time:*' extracts all EXIF Time tags). And finally, a
leading '-' indicates a tag to be excluded (eg. '-IFD1:*'), or a
trailing '#' causes the ValueConv value to be returned for this
tag.

Note that keys in the returned information hash and elements of
the returned tag list are not necessarily the same as these tag
names because group names are removed, the case may be changed,
and an instance number may be added. For this reason it is best
to use either the keys of the returned hash or the elements of
the returned tag list when accessing the tag values.

See Image::ExifTool::TagNames for a complete list of ExifTool
tag names.

File ref
A reference to an open image file. If you use this method (or a
SCALAR reference) to access information in an image, the
FileName and Directory tags will not be returned. (Also, a
number of the File System tags will not be returned unless it is
a plain file.) Image processing begins at the current file
position, and on return the file position is unspecified. May
be either a standard filehandle, or a reference to a
File::RandomAccess object. Note that the file remains open and
must be closed by the caller after "ImageInfo" returns.

[Advanced: To allow a non-rewindable stream (eg. a network
socket) to be re-read after processing with ExifTool, first wrap
the file reference in a File::RandomAccess object, then pass
this object to "ImageInfo". The File::RandomAccess object will
buffer the file if necessary, and may be used to re-read the
file after "ImageInfo" returns.]

SCALAR ref
A reference to image data in memory.

ARRAY ref
Reference to a list of tag names. On entry, any elements in the
list are added to the list of requested tags. Tags with names
beginning with '-' are excluded. On return, this list is
updated to contain an ordered list of tag keys for the returned
information.

There will be 1:1 correspondence between the requested tags and
the returned tag keys only if the "Duplicates" option is 0 and
"Sort" is 'Input'. (With "Duplicates" enabled, there may be
more entries in the returned list of tag keys, and with other
"Sort" settings the entries may not be in the same order as
requested.) If a requested tag doesn't exist, a tag key is
still generated, but the tag value is undefined.

Note: Do not reuse this list in subsequent calls to "ImageInfo"
because it returns tag keys, not names, and the list will grow
for each call resulting in increasingly slower performance.

HASH ref
Reference to a hash containing the options settings valid for
this call only. See "Options" documentation below for a list of
available options. Options specified as arguments to
"ImageInfo" take precedence over "Options" settings.

Return Values:
"ImageInfo" returns a reference to a hash of tag-key/value pairs.
The tag keys are identifiers -- essentially case-sensitive tag names
with an appended instance number if multiple tags with the same name
were extracted from the image. Many of the ExifTool functions
require a tag key as an argument. Use "GetTagName [static]" to get
the tag name for a given tag key. Note that the case of the tag
names may not be the same as requested. Here is a simple example to
print out the information returned by "ImageInfo":

foreach (sort keys %$info) {
print "$_ => $$info{$_}\n";
}

Values of the returned hash are usually simple scalars, but a scalar
reference is used to indicate binary data and an array reference may
be used to indicate a list. Also, a hash reference may be returned
if the "Struct" option is used (see the "OrderedKeys" option to
obtain the hash keys). Lists of values are joined by commas into a
single string only if the PrintConv option is enabled and the
ListJoin option is enabled (which are the defaults). Note that
binary values are not necessarily extracted unless specifically
requested, or the Binary option is enabled and the tag is not
specifically excluded. If not extracted the value is a reference to
a string of the form "Binary data ##### bytes".

The code below gives an example of how to handle these return
values, as well as illustrating the use of other ExifTool functions:

use Image::ExifTool;
my $exifTool = Image::ExifTool->new;
$exifTool->Options(Unknown => 1);
my $info = $exifTool->ImageInfo('a.jpg');
my $group = '';
my $tag;
foreach $tag ($exifTool->GetFoundTags('Group0')) {
if ($group ne $exifTool->GetGroup($tag)) {
$group = $exifTool->GetGroup($tag);
print "---- $group ----\n";
}
my $val = $info->{$tag};
if (ref $val eq 'SCALAR') {
if ($$val =~ /^Binary data/) {
$val = "($$val)";
} else {
my $len = length($$val);
$val = "(Binary data $len bytes)";
}
}
printf("%-32s : %s\n", $exifTool->GetDescription($tag), $val);
}

Notes:
ExifTool returns all values as byte strings of encoded characters.
Perl wide characters are not used. See "CHARACTER ENCODINGS" for
details about the encodings. By default, most returned values are
encoded in UTF-8. For these, Encode::decode_utf8() may be used to
convert to a sequence of logical Perl characters.

As well as tags representing information extracted from the image,
the following Extra tags generated by ExifTool may be returned:

ExifToolVersion - The ExifTool version number.

Error - An error message if the image could not be processed.

Warning - A warning message if problems were encountered while
processing the image.

Options
Get/set ExifTool options. This function can be called to set the
default options for an ExifTool object. Options set this way are in
effect for all function calls but may be overridden by options passed as
arguments to some functions. Option names are not case sensitive, but
option values are.

The default option values may be changed by defining a
%Image::ExifTool::UserDefined::Options hash. See the ExifTool_config
file in the full ExifTool distribution for examples. Unless otherwise
noted, a default of undef has the same effect as a value of 0 for
options with numerical values.

# exclude the 'OwnerName' tag from returned information
$exifTool->Options(Exclude => 'OwnerName');

# only get information in EXIF or MakerNotes groups
$exifTool->Options(Group0 => ['EXIF', 'MakerNotes']);

# ignore information from IFD1
$exifTool->Options(Group1 => '-IFD1');

# sort by groups in family 2, and extract unknown tags
$exifTool->Options(Sort => 'Group2', Unknown => 1);

# reset DateFormat option
$exifTool->Options(DateFormat => undef);

# do not extract duplicate tag names
$oldSetting = $exifTool->Options(Duplicates => 0);

# get current Verbose setting
$isVerbose = $exifTool->Options('Verbose');

# set a user parameter
$exifTool->Options(UserParam => 'MyParam=some value');

Inputs:
0) ExifTool object reference

1) Option parameter name (case-insensitive)

2) [optional] Option parameter value (may be undef to clear option)

3-N) [optional] Additional parameter/value pairs

Option Parameters:
Note that these API options may also be used in the exiftool
application via the command-line -api option.

Binary
Flag to extract the value data for all binary tags. Tag values
representing large binary data blocks (eg. ThumbnailImage) are
not necessarily extracted unless this option is set or the tag
is specifically requested by name. Default is undef.

BlockExtract
Flag to extract some directories (mentioned in the ExifTool tag
name documentation) as a block. Setting this to a value of 2
also prevents parsing the block to extract tags contained
within.

ByteOrder
The byte order for newly created EXIF segments when writing.
Note that if EXIF information already exists, the existing order
is maintained. Valid values are 'MM', 'II' and undef. If
ByteOrder is not defined (the default), then the maker note byte
order is used (if they are being copied), otherwise big-endian
('MM') order is assumed. This can also be set via the
ExifByteOrder tag, but the ByteOrder option takes precedence if
both are set.

ByteUnit
Units for print conversion of FileSize and other byte values.
Either 'SI' (eg. kB for 1000 bytes) or 'Binary' (eg. KiB for
1024 bytes). Default is 'SI'.

Charset
Character set for encoding character tag values passed to/from
ExifTool with code points above U+007F. Default is 'UTF8'.
Valid values are listed below, case is not significant:

Value Alias(es) Description
----------- --------------- ----------------------------------
UTF8 cp65001, UTF-8 UTF-8 characters
Latin cp1252, Latin1 Windows Latin1 (West European)
Latin2 cp1250 Windows Latin2 (Central European)
Cyrillic cp1251, Russian Windows Cyrillic
Greek cp1253 Windows Greek
Turkish cp1254 Windows Turkish
Hebrew cp1255 Windows Hebrew
Arabic cp1256 Windows Arabic
Baltic cp1257 Windows Baltic
Vietnam cp1258 Windows Vietnamese
Thai cp874 Windows Thai
DOSLatinUS cp437 DOS Latin US
DOSLatin1 cp850 DOS Latin1
DOSCyrillic cp866 DOS Cyrillic
MacRoman cp10000, Roman Macintosh Roman
MacLatin2 cp10029 Macintosh Latin2 (Central Europe)
MacCyrillic cp10007 Macintosh Cyrillic
MacGreek cp10006 Macintosh Greek
MacTurkish cp10081 Macintosh Turkish
MacRomanian cp10010 Macintosh Romanian
MacIceland cp10079 Macintosh Icelandic
MacCroatian cp10082 Macintosh Croatian

Note that this option affects some types of information when
reading/writing the file and other types when getting/setting
tag values, so it must be defined for both types of access. See
the "CHARACTER ENCODINGS" section for more information about the
handling of special characters.

CharsetEXIF
Internal encoding to use for stored EXIF "ASCII" string values.
May also be set to undef to pass through EXIF "ASCII" values
without recoding. Set to "UTF8" to conform with the MWG
recommendation. Default is undef.

CharsetFileName
External character set used for file names passed to ExifTool
functions. Default is undef but "UTF8" is assumed in Windows if
the file name contains special characters and is valid UTF8.
May also be set to an empty string to avoid "encoding must be
specified" warnings on Windows.

CharsetID3
Internal encoding to assume for ID3v1 strings. By the
specification ID3v1 strings should be encoded in ISO 8859-1
(essentially Latin), but some applications may use local
encoding instead. Default is 'Latin'.

CharsetIPTC
Fallback internal IPTC character set to assume if IPTC
information contains no CodedCharacterSet tag. Possible values
are the same as the "Charset" option. Default is 'Latin'.

Note that this option affects some types of information when
reading/writing the file and other types when getting/setting
tag values, so it must be defined for both types of access.

CharsetPhotoshop
Internal encoding to assume for Photoshop IRB resource names.
Default is 'Latin'.

CharsetQuickTime
Internal encoding to assume for QuickTime strings stored with an
unspecified encoding. Default is 'MacRoman'.

CharsetRIFF
Internal encoding to assume for strings in RIFF metadata (eg.
AVI and WAV files). The default value of 0 assumes "Latin"
encoding unless otherwise specified by the RIFF CSET chunk. Set
to undef to pass through strings without recoding. Default is
0.

Compact
Comma-delimited list of settings for writing compact XMP. Below
is a list of available settings. Note that 'NoPadding' effects
only embedded XMP since padding is never written for stand-alone
XMP files. Also note that 'OneDesc' is not recommended when
writing XMP larger than 64 KiB to a JPG file because it
interferes with ExifTool's technique of splitting off large
rdf:Description elements into the extended XMP. Case is not
significant for any of these options. Aliases are given in
brackets. Default is undef.

NoPadding - Avoid 2 KiB of recommended padding at end of XMP (NoPad)
NoIndent - No spaces to indent lines (NoSpace, NoSpaces)
NoNewline - Avoid unnecessary newlines (NoNewlines)
Shorthand - Use XMP Shorthand format
OneDesc - Combine properties into a single rdf:Description (OneDescr)
AllSpace - Equivalent to 'NoPadding,NoIndent,NoNewline'
AllFormat - Equivalent to 'Shorthand,OneDesc'
All - Equivalent to 'AllSpace,AllFormat'

Composite
Flag to generate Composite tags when extracting information.
Default is 1.

Compress
Flag to write new values in compressed format if possible. Has
no effect unless the relevant compression library is available.
Valid when writing metadata to PNG, JXL, HEIC or MIE images.
Setting this to zero causes JXL metadata to be rewritten as
uncompressed when edited. Default is undef.

CoordFormat
Format for printing GPS coordinates. This is a printf format
string with specifiers for degrees, minutes and seconds in that
order, however minutes and seconds may be omitted. If the
hemisphere is known, a reference direction (N, S, E or W) is
appended to each printed coordinate, but adding a "+" or "-" to
the first format specifier (eg. "%+.6f" or "%-.6f") prints a
signed coordinate instead ("+" also adds a leading plus sign to
positive coordinates, while "-" does not). For example, the
following table gives the output for the same coordinate using
various formats:

CoordFormat Example Output
------------------- ------------------
q{%d deg %d' %.2f"} 54 deg 59' 22.80" (default for reading)
q{%d %d %.8f} 54 59 22.80000000 (default for copying)
q{%d deg %.4f min} 54 deg 59.3800 min
q{%.6f degrees} 54.989667 degrees

Note: To avoid loss of precision, the default coordinate format
is different when copying tags with "SetNewValuesFromFile".

DateFormat
Format for printing date/time values. See "strftime" in the
POSIX package and <https://exiftool.org/filename.html#codes> for
details about the format string. If the date can not be
converted, the value is left unchanged unless the StrictDate
option is set. ExifTool adds a few additional format specifiers
(%f, %s and %z), see <https://exiftool.org/filename.html#codes>
for more details. The inverse conversion (ie. when calling
"SetNewValue") is performed only if POSIX::strptime or
Time::Piece is installed. The default setting of undef causes
date/time values to remain in standard EXIF format (similar to a
DateFormat of "%Y:%m:%d %H:%M:%S").

Duplicates
Flag to return values from tags with duplicate names when
extracting information. Default is 1. Forced to 1 when copying
tags with "SetNewValuesFromFile".

Escape
Escape special characters in extracted values for HTML or XML.
Also unescapes HTML or XML character entities in input values
passed to "SetNewValue". Valid settings are 'HTML', 'XML' or
undef. Default is undef.

Exclude
Exclude specified tags when extracting information. Note that
this option is applied after all of the tags have already been
loaded into memory (so different tags may be excluded in
subsequent calls to "GetInfo"). See the IgnoreTags option to
save memory by not loading the tags in the first place. The
option value is either a tag name or reference to a list of tag
names to exclude. The case of tag names is not significant.
This option is ignored for specifically requested tags. Tags
may also be excluded by preceding their name with a '-' in the
arguments to "ImageInfo".

ExtendedXMP
This setting affects the reading and editing of extended XMP in
JPEG images. According to the XMP specification, extended XMP
is only valid if it has the GUID specified by the HasExtendedXMP
tag, so by default ExifTool will ignore other extended XMP, but
this option allows full control over the extended XMP to be
extracted.

0 - Ignore all extended XMP
1 - Read extended XMP with valid GUID only (default)
2 - Read extended XMP with any GUID
<guid> - Read extended XMP with a specific GUID

ExtractEmbedded
Flag to extract information from embedded documents in EPS
files, embedded EPS information and JPEG and Jpeg2000 images in
PDF files, embedded MPF images in JPEG and MPO files, metadata
after the first Cluster in MKV files, timed metadata in videos,
all frames of a multipart EXR image, and the resource fork of
Mac OS files. A setting of 2 also causes the H264 video stream
in MP4 files to be parsed until the first SEI message is
decoded, or 3 to parse the entire H264 stream in MP4 videos and
the entire M2TS file to look for any unlisted program containing
GPS metadata. Default is undef.

FastScan
Flag to increase speed when reading files by avoiding extraction
of some types of metadata. With this option set to 1, ExifTool
will not scan to the end of a JPEG image to check for an AFCP,
CanonVRD, FotoStation, PhotoMechanic, MIE or PreviewImage
trailer. This also stops the parsing after the first comment in
GIF images, and at the audio/video data of RIFF-format files
(AVI, WAV, etc), so any trailing metadata (eg. XMP written by
some utilities) may be missed. Also disables input buffering
for some types of files to reduce memory usage when reading from
a non-seekable stream, and bypasses CRC validation for speed
when writing PNG files. When combined with the ScanForXMP
option, prevents scanning for XMP in recognized file types.
With a value of 2, ExifTool will also avoid extracting any EXIF
MakerNote information, and will stop processing at the IDAT
chunk of PNG images and the mdat atom in QuickTime-format files.
(By the PNG specification, metadata is allowed after IDAT, but
ExifTool always writes it before because some utilities will
ignore it otherwise.) When set to 3 or higher, only pseudo
system tags and FileType are generated. For 3, the file header
is read to provide an educated guess at FileType. For 4, the
file is not read at all and FileType is determined based on the
file's extension. For 5, generation of Composite tags is also
disabled (like setting "Composite" to 0). Default is undef.

Filter
Perl expression used to filter values for all tags. The
expression acts on the value of the Perl default variable ($_),
and changes the value of this variable as required. The current
ExifTool object may be accessed through $self. The value is not
changed if $_ is set to undef. List items are filtered
individually. Applies to all returned values unless PrintConv
option is disabled.

FilterW
Perl expression used to filter PrintConv values when writing.
The expression acts on the value of the Perl default variable
($_), and changes the value of this variable as required. The
current ExifTool object may be accessed through $self. The tag
is not written if $_ is set to undef.

FixBase
Fix maker notes base offset. A common problem with image
editing software is that offsets in the maker notes are not
adjusted properly when the file is modified. This may cause the
wrong values to be extracted for some maker note entries when
reading the edited file. FixBase specifies an integer value to
be added to the maker notes base offset. It may also be set to
the empty string ('') for ExifTool will take its best guess at
the correct base, or undef (the default) for no base adjustment.

GeoDir
[Not a real option] Provided as a convenience to allow
$Image::ExifTool::geoDir to be set at runtime. This variable
specifies the directory for the Geolocation databases, and is
used only once when these databases are loaded.

Geolocation
Flag to generate geolocation tags based on the
GPSLatitude/GPSLongitude or City/State/Province/Country read
from a file. This feature uses an included database with cities
over a population of 2000 from geonames.org. May be set to a
string of the form "Lat,Lon" (eg. "44.56,-72.33") or city with
optional state/province, country and/or country code (eg.
"Paris,France") to act as a default for files not containing GPS
or geolocation information, or include tag names with leading
dollar signs separated by commas to specify the tags to use for
the geolocation input. When "Lat,Lon" is specified, "num=##"
may be added to return the specified number of nearby cities
(the "Duplicates" option must also be used for the duplicate
tags to be returned). May include regular expressions for more
flexible matching of city names. See
<https://exiftool.org/geolocation.html> for more details.
Default is undef.

GeolocAltNames
Flag to search alternate Geolocation city names if available
(ie. if $Image::ExifTool::Geolocation::altDir has been set).
Set to 0 to disable use of the alternate names. Default is 1.

GeolocFeature
Comma-separated list of feature codes to include in city search,
or exclude if the list begins with a dash (-). Valid feature
codes are PPL, PPLA, PPLA2, PPLA3, PPLA4, PPLA5, PPLC, PPLCH,
PPLF, PPLG, PPLH, PPLL, PPLQ, PPLR, PPLS, PPLW, PPLX, STLMT and
Other, plus possible user-include codes if an alternate database
is used. See <http://www.geonames.org/export/codes.html#P> for
a description of these codes. Default is undef.

GeolocMaxDist
Maximum distance in km to the geolocation city. The Geolocation
tags are not generated if the distance is greater than this.
Default is undef.

GeolocMinPop
Minimum population for the Geolocation city. Cities smaller
than this are ignored. Default is undef.

GeoMaxIntSecs
Maximum interpolation time in seconds for geotagging.
Geotagging is treated as an extrapolation if the Geotime value
lies between two fixes in the same track which are separated by
a number of seconds greater than this. Otherwise, the
coordinates are calculated as a linear interpolation between the
nearest fixes on either side of the Geotime value. Set to 0 to
disable interpolation and use the coordinates of the nearest fix
instead (provided it is within GeoMaxExtSecs, otherwise
geotagging fails). Default is 1800.

GeoMaxExtSecs
Maximum extrapolation time in seconds for geotagging.
Geotagging fails if the Geotime value lies outside a GPS track
by a number of seconds greater than this. Otherwise, for an
extrapolation the coordinates of the nearest fix are taken (ie.
it is assumed that you weren't moving during this period).
Default is 1800.

GeoMaxHDOP
Maximum Horizontal (2D) Dilution Of Precision for geotagging.
GPS fixes are ignored if the HDOP is greater than this. Default
is undef.

GeoMaxPDOP
Maximum Position (3D) Dilution Of Precision for geotagging. GPS
fixes are ignored if the PDOP is greater than this. Default is
undef.

GeoMinSats
Minimum number of satellites for geotagging. GPS fixes are
ignored if the number of acquired satellites is less than this.
Default is undef.

GeoSpeedRef
Reference units for writing GPSSpeed when geotagging:

'K', 'k' or 'km/h' - km/h
'M', 'm' or 'mph' - mph
<anything else> - knots (default undef)

GlobalTimeShift
Time shift to apply to all extracted date/time PrintConv values.
Does not affect ValueConv values. Value is a date/time shift
string (see Image::ExifTool::Shift(3pm)) with a leading '-' for
negative shifts, or a tag name with option group prefix followed
by '+' or '-' then the shift string. Default is undef.

Note: When specifying a number of months and/or years to shift,
the tag for the starting date should be specified so the number
of days can be determined unambiguously. For example:

'createdate-1:0:0 0:0:0' - shift back by the length of the
year before the CreateDate value
'xmp:createdate+0:2:0 0' - shift forward by the length of
the 2 months after XMP:CreateDate

If the starting tag is not specified, or the specified tag isn't
available, then the shift is calculated based on the first
shifted tag.

GPSQuadrant
This option is used to specify the GPS quadrant in the case
where a warning was issued because the GPS quadrant couldn't be
determined. The value is a 2-character code where the first
character is 'N' or 'S' and the second character is 'E' or 'W'
(case insensitive). If this option is not set and the quadrant
is unknown, a warning is issued and the quadrant is assumed to
be 'NE'.

Group#
Extract tags only for specified groups in family # (Group0
assumed if # not given). The option value may be a single group
name or a reference to a list of groups. Case is significant in
group names. Specify a group to be excluded by preceding group
name with a '-'. See "GetGroup" for a description of group
families, and "GetAllGroups [static]" for lists of group names.

HexTagIDs
Return hexadecimal instead of decimal for the family 7 group
names of tags with numerical ID's.

HtmlDump
Dump information in hex to dynamic HTML web page. The value may
be 0-3 for increasingly larger limits on the maximum block size.
Default is 0. Output goes to the file specified by the TextOut
option (\*STDOUT by default).

HtmlDumpBase
Base for HTML dump offsets. If not defined, the EXIF/TIFF base
offset is used. Set to 0 for absolute offsets. Default is
undef.

IgnoreGroups
Comma-separated list of group names to ignore when reading. The
group names are case insensitive and may be preceded by a family
number. Set to undef to clear the previous IgnoreGroups list.
Default is undef.

IgnoreMinorErrors
Flag to ignore minor errors. Causes minor errors to be
downgraded to warnings, and minor warnings to be ignored. This
option is provided mainly to allow writing of files when minor
errors occur, but by ignoring some minor warnings the behaviour
of ExifTool may be changed to allow some questionable operations
to proceed (such as extracting thumbnail and preview images even
if they don't have a recognizable header). Minor errors and
warnings are denoted by "[minor]" at the start of the message,
or "[Minor]" (with a capital "M") for warnings that affect
processing when ignored.

IgnoreTags
Comma-separated list of tag names to ignore when reading. This
may help in situations where memory is limited because the
ignored tag values are not stored in memory. The tag names are
case insensitive and group names and wildcards are not allowed.
A special tag name of "All" may be used to ignore all tags
except those specified by the "RequestTags" option. Set to
undef to clear the previous IgnoreTags list. Default is undef.

ImageHashType
Sets type of hash algorithm used for the ImageDataHash tag
calculation. Supported options are 'MD5', 'SHA256', and
'SHA512'. Default is 'MD5'.

KeepUTCTime
Flag to keep UTC times in Zulu time zone instead of converting
to local time. Default is undef.

Lang
Localized language for exiftool tag descriptions, etc.
Available languages are given by the Image::ExifTool::Lang
module names (eg. 'fr', 'zh_cn'). If the specified language
isn't available, the option is not changed. May be set to undef
to select the built-in default language. Default is 'en'.

LargeFileSupport
Flag to indicate that 64-bit file offsets are supported on this
system. If not set, processing is aborted if a chunk larger than
2 GB is encountered. Set to 1 to process large chunks, or 2 to
process with a warning. Default is 1.

LimitLongValues
When extracting values for some specific tags (usually Unknown
tags), the PrintConv values are length-limited and the value is
truncated with an ellipsis ("[...]") if it exceeds a specified
length. This option specifies the length limit for these tags.
A setting of 4 or less disables the limit (because the ellipsis
string is longer than this). Default is 60.

ListItem
Return only a specific item from list-type values. A value of 0
returns the first item in the list, 1 return the second item,
etc. Negative indices may also be used, with -1 representing
the last item in the list. Applies only to the top-level list
of nested lists. Default is undef to return all items in the
list.

ListJoin
Separator used to join the PrintConv value of multi-item List-
type tags into a single string. If not defined, multi-item
lists are returned as a list reference. Does not affect
ValueConv values. Default is ', '.

ListSplit
Regular expression used to split values of list-type tags into
individual items when writing. (eg. use ',\\s*' to split a
comma-separated list.) Split when writing either PrintConv or
ValueConv values. Default is undef.

MakerNotes
Option to extract MakerNotes and other writable subdirectories
(such as PrintIM) as a data block. Normally when the MakerNotes
are extracted they are rebuilt to include data outside the
boundaries of the original maker note data block, but a value of
2 disables this feature. Possible values are:

0 - Do not extract writable subdirectories (same as default of undef)
1 - Extract and rebuild maker notes into self-contained block
2 - Extract without rebuilding maker notes

MDItemTags
Flag to extract the OS X metadata item tags (see the "mdls" man
page and "MacOS MDItem Tags" in Image::ExifTool::TagNames for
more information).

MissingTagValue
Value for missing tags in tag name expressions (or tags where
the advanced formatting expression returns undef). If not set,
a minor error is issued for missing values, or the value is set
to '' if "IgnoreMinorErrors" is set. Default is undef.

NoDups
Flag to remove duplicate items from queued values for List-type
tags when writing. This applies only to queued values, and
doesn't resolve duplicates with existing values in the file when
adding to an existing list. Default is undef.

NoMandatory
Flag to bypass writing of mandatory EXIF tags. Default is
undef.

NoMultiExif
Raise error when attempting to write multi-segment EXIF in a
JPEG image. Default is undef.

NoPDFList
Flag to avoid splitting PDF list-type tag values into separate
items. Default is undef.

NoWarning[+]
Regular expression to suppress matching warning messages. For
example, a value of "^Ignored" suppresses all warnings that
begin with the word "Ignored". Has no other effect on
processing, unlike IgnoreMinorWarnings for some warnings. Start
the expression with "(?i)" for case-insensitive matching. Use
NoWarning+ to add to existing expressions. Default is undef.

Password
Password for reading/writing password-protected PDF documents.
Ignored if a password is not required. Character encoding of
the password is determined by the value of the Charset option at
processing time. Default is undef.

Plot
Settings to override defaults for SVG plot feature. Value is a
comma delimited string of settings, or undef to revert to
default settings. Settings are accumulated if this option is
set multiple times. Commas in the settings must be escaped as
"&#44;". Valid settings and their default values are:

"Type=Line" - plot type (Line, Scatter or Histogram)
"Style=Line" - data style (Line, Marker and/or Fill)
"NBins=20" - number of bins for histogram plot
"Size=800 600" - width,height of output image
"Margin=60 15 15 30" - left,top,right,bottom margins around plot area
"Legend=0 0" - x,y offset to shift plot legend
"TxtPad=10 10" - padding between text and x,y scale
"LineSpacing=20" - spacing between text lines
"Stroke=1" - plot stroke width and marker-size scaling
Title, XLabel, YLabel - plot title and x/y axis labels (no default)
XMin, XMax - x axis minimum/maximum (autoscaling if not set)
YMin, YMax - y axis minimum/maximum
Multi - flag to draw multiple plots, one for each dataset
Split - flag to split strings of numbers into lists
(> 1 to split into lists of N items)
"Grid=darkgray" - grid color
"Text=black" - color of text and plot border
"Bkg=" - background color (default is transparent)
"Cols=red green blue black orange gray fuchsia brown turquoise gold"
- colors for plot data
"Marks=circle square triangle diamond star plus pentagon left down right"
- marker-shape names for each dataset

PrintConv
Flag to enable automatic print conversion. Also enables inverse
print conversion for writing. Default is 1.

PrintCSV
Flag to directly print CSV-format output rather than extracting
tags normally. Currently this feature applies only to GM PDR
data (see "GM Tags" in Image::ExifTool::TagNames). Setting this
option automatically sets "IgnoreTags" to "all", and
"ExtractEmbedded" to 1. Default is undef.

QuickTimeHandler
Flag set to add an 'mdir' Handler to a newly created Meta box
when adding QuickTime ItemList tags. Adobe Bridge does not add
this Handler, but it is commonly found in samples from other
software, and it has been reported that Apple QuickTime Player
and Photos.apps will ignore ItemList tags if this is missing.
Default is 1.

QuickTimePad
Flag to preserve the padding of some QuickTime atoms when
writing. QuickTime-based Canon CR3 files pad the values of
container atoms with null bytes. This padding is removed by
default when the file is rewritten, but setting this option to 1
adds padding to preserve the original atom size if the new atom
would be smaller than the original. Default is undef.

QuickTimeUTC
Flag set to assume that QuickTime date/time values are stored as
UTC, causing conversion to local time when they are extracted
and from local time when written. According to the QuickTime
specification date/time values should be UTC, but many digital
cameras store local time instead (presumably because they don't
know the time zone), so the default is to not convert these
times (except for Canon CR3 files, which always use UTC times).
This option also disables the auto-detection of incorrect time-
zero offsets in QuickTime date/time values, and enforces a time
zero of 1904 as per the QuickTime specification.

RequestAll
Flag to request all tags to be extracted. This causes some tags
to be generated which normally would not be unless specifically
requested (by passing the tag name to "ImageInfo" or
"ExtractInfo"). May be set to 2 or 3 to enable generation of
some additional tags as mentioned in the tag name documentation.
Default is undef.

RequestTags
List of additional tag and/or group names to request in the next
call to "ExtractInfo". This option is useful only for
tags/groups which aren't extracted unless specifically
requested. Value may be a list reference, a delimited string of
names (any delimiter is allowed), or undef to clear the current
RequestTags list. Groups are requested by adding a colon after
the name (eg. "MacOS:"). Names are converted to lower case as
they are added to the list. Default is undef.

SaveBin
Flag to save binary values of tags, accessible through calls to
"GetValue" with a value type of "Bin".

SaveFormat
Flag to save EXIF/TIFF format type as the family 6 group name
when extracting information. Without this option set, the
family 6 group names are not generated. Default is undef. See
"GetGroup" for more details.

SavePath
Flag to save the metadata path as the family 5 group name when
extracting information. Without this option set, the family 5
group names are not generated. Default is undef. See the
"GetGroup" option for more details.

ScanForXMP
Flag to scan all files (even unrecognized formats) for XMP
information unless XMP was already found in the file. When
combined with the FastScan option, only unrecognized file types
are scanned for XMP. Default is undef.

Sort
Specifies order to sort tags in returned list:

Input - Sort in same order as input tag arguments (default)
File - Sort in order that tags were found in the file
Tag - Sort alphabetically by tag name
Descr - Sort by tag description (for current Lang setting)
Group# - Sort by tag group, where # is zero or more family
numbers separated by colons. If # is not specified,
Group0 is assumed. See GetGroup for a description
of group families.

Sort2
Secondary sort order used for tags within each group when Sort
is 'Group':

File - Sort in order tags were found in the file (default)
Tag - Sort alphabetically by tag name
Descr - Sort by tag description (for current Lang setting)

StrictDate
Flag to return undefined value for any date which can't be
converted when the DateFormat option is used. Default is undef.

undef - Same as 0 for reading/writing, or 1 for copying
0 - Return date/time value unchanged if it can't be converted
1 - Return undef if date/time value can't be converted

When set to 1 while writing a PrintConv date/time value with the
DateFormat option set, the value is written only if
POSIX::strptime or Time::Piece is available and can successfully
convert the value.

For PNG CreationTime, a setting of 1 has the additional effect
of causing the date/time to be reformatted according to PNG 1.2
recommendation (RFC-1123) when writing, and a warning to be
issued for any non-standard value when reading (but note that
Windows may not recognize PNG date/time values in standard
format).

Struct
Flag to return XMP structures as hash references instead of
flattening into individual tags. Has no effect when writing
since both flattened and structured tags may always be written.
A special "_ordered_keys_" element containing a list of ordered
keys may exist if the structure elements are ordered (see the
OrderedKeys method). Possible values are:

undef - (default) Same as 0 for reading, 2 for copying
0 - Read/copy flattened tags
1 - Read/copy structured tags
2 - Read/copy both flattened and structured tags, but flag
flattened tags as 'unsafe' for copying

StructFormat
Format for serialized structures when reading/writing.

undef - Default ExifTool format
JSON - JSON format
JSONQ - JSON with quoted numerical values

Note that the JSONQ setting causes all values in the exiftool
application -json output to be quoted, regardless of whether or
not they are in a structure.

SystemTags
Flag to extract the following additional File System tags:
FileAttributes, FileDeviceNumber, FileInodeNumber,
FileHardLinks, FileUserID, FileGroupID, FileDeviceID,
FileBlockSize and FileBlockCount.

TextOut
Output file reference for Verbose and HtmlDump options. Default
is \*STDOUT.

TimeZone
Set the time zone for local date/time values. The value is a
time zone offset like "+05:00" (but note that the offset is to
UTC, not from UTC, so it is positive for western time zones), or
a time zone name like "EST5EDT". For Unix-based systems, the
value may also be a time zone ID like "America/New_York".
Requires Time::Piece on Windows, or POSIX::tzset on other
systems. Default is undef.

Unknown
Flag to get the values of unknown tags. If set to 1, unknown
tags are extracted from EXIF (or other tagged-format)
directories. If set to 2, unknown tags are also extracted from
binary data blocks. Default is 0.

UserParam
Special option to set/get user-defined parameters. Useful to
allow external input into tag name expressions and ValueConv
logic. Valid UserParam values are:

PARAM - Get parameter
PARAM= - Clear parameter
PARAM^= - Set parameter to empty string
PARAM=VALUE - Set parameter
<hash ref> - Set entire UserParam hash lookup
undef - Clear all user parameters

Where PARAM is the user-defined parameter name (case
insensitive).

User-defined parameters may be accessed in tag name expressions
by prefixing the parameter name with a dollar sign just like
normal tags, or via the API by calling
"Options('UserParam','PARAM')". Appending a hash tag ("#") to
the parameter name also causes the parameter to be extracted as
a normal tag (in the UserParam group). If called without
additional arguments, Options('UserParam') returns a reference
to the hash of all user parameters (with lower-case names).

Validate
Flag to perform extra validation metadata checks when reading,
causing extra warnings to be generated if problems are found.
Default is undef.

Verbose
Print verbose messages to file specified by TextOut option.
Value may be from 0 to 5 for increasingly verbose messages.
Default is 0. With the verbose option set, messages are printed
to the console as the file is parsed. Level 1 prints the tag
names and raw values. Level 2 adds more details about the tags.
Level 3 adds a hex dump of the tag data, but with limits on the
number of bytes dumped. Levels 4 and 5 remove the dump limit on
tag values and JPEG segment data respectively.

WindowsLongPath
Support long path names in Windows. Enabling this option
automatically enables the WindowsWideFile feature. Default is
1.

WindowsWideFile
Force the use of wide-character Windows I/O functions. This may
be necessary when files are on a network drive and the current
directory name contains Unicode characters. Without this option
the wide-character functions are used only if the specified file
path contains Unicode characters.

WriteMode
Set tag write/create mode. Value is a string of one or more
characters from list below. Default is 'wcg'.

w - Write existing tags
c - Create new tags
g - create new Groups as necessary

The level of the group differs for different types of metadata.
For XMP or IPTC this is the full XMP/IPTC block (the family 0
group), but for EXIF this is the individual IFD (the family 1
group). The 'w' and 'c' modes are tested only when
"SetNewValue" is called, but the 'g' mode is also tested in
"WriteInfo".

XAttrTags
Flag to extract the OS X extended attribute tags (see the
"xattr" man page and "MacOS XAttr Tags" in
Image::ExifTool::TagNames for more information).

XMPAutoConv
Flag to enable automatic conversion for unknown XMP tags with
values that look like rational numbers or dates. Default is 1.

Return Values:
The original value of the last specified parameter.

ClearOptions
Reset all options to their default values. Loads user-defined default
option values from the %Image::ExifTool::UserDefined::Options hash in
the .ExifTool_config file if it exists.

$exifTool->ClearOptions();

Inputs:
0) ExifTool object reference

Return Values:
(none)

ExtractInfo
Extract all meta information from an image.

$success = $exifTool->ExtractInfo('image.jpg', \%options);

Inputs:
"ExtractInfo" takes exactly the same arguments as "ImageInfo". The
only difference is that a list of tag keys is not returned if an
ARRAY reference is given.

Return Value:
1 if this was a recognized file format, 0 otherwise (and 'Error' tag
set).

GetInfo
"GetInfo" is called to return meta information after it has been
extracted from the image by a previous call to "ExtractInfo" or
"ImageInfo". This function may be called repeatedly after a single call
to "ExtractInfo" or "ImageInfo".

# get image width and height only
$info = $exifTool->GetInfo('ImageWidth', 'ImageHeight');

# get all Error and Warning messages
$info = $exifTool->GetInfo('Error', 'Warning');

# get information for all tags in list (list updated with tags found)
$info = $exifTool->GetInfo(\@ioTagList);

# get all information in Author or Location groups
$info = $exifTool->GetInfo({Group2 => ['Author', 'Location']});

Inputs:
Inputs are the same as "ExtractInfo" and "ImageInfo" except that an
image can not be specified.

Return Value:
Reference to information hash, the same as with "ImageInfo".

WriteInfo
Write meta information to a file. The specified source file is
rewritten to the same-type destination file with new information as
specified by previous calls to "SetNewValue". The necessary segments
and/or directories are created in the destination file as required to
store the specified information. May be called repeatedly to write the
same information to additional files without the need to call
"SetNewValue" again.

ExifTool queues all new values that are assigned via calls to
"SetNewValue", then applies them to any number of files through one or
more calls to "WriteInfo". These queued values may be accessed through
"GetNewValue", and are completely separate from metadata extracted from
files via "ExtractInfo" or "ImageInfo" and accessed through "GetInfo" or
"GetValue".

To be clear, it is NOT necessary to call "ExtractInfo" or "ImageInfo"
before "WriteInfo". "WriteInfo" changes only metadata specified by
previous calls to "SetNewValue".

# add information to a source file, writing output to new file
$exifTool->WriteInfo($srcfile, $dstfile);

# create XMP data file from scratch
$exifTool->WriteInfo(undef, $dstfile, 'XMP');

# overwrite file (you do have backups, right?)
$exifTool->WriteInfo($srcfile);

Inputs:
0) ExifTool object reference

1) Source file name, file reference, scalar reference, or undef to
create a file from scratch. A reference to a File::RandomAccess
object is also allowed as a source, but in this case the destination
is not optional.

2) [optional] Destination file name, file reference, scalar
reference to write to memory, or undef to overwrite the original
file. May be '-' to write to stdout.

3) [optional] Destination file type. Ignored if a source is
defined.

Return Value:
1 if file was written OK, 2 if file was written but no changes made,
0 on file write error.

If an error code is returned, an Error tag is set and
GetValue('Error') can be called to obtain the error description. A
Warning tag may be set even if this routine is successful. Calling
WriteInfo clears any pre-existing Error and Warning tags.

$errorMessage = $exifTool->GetValue('Error');
$warningMessage = $exifTool->GetValue('Warning');

Notes:
The source file name may be undefined to create a file from scratch
(currently only XMP, MIE, ICC, VRD, DR4, EXV and EXIF files can be
created in this way -- see "CanCreate" for details). If undefined,
the destination file type is required unless the type can be
determined from the extension of the destination file name.

If a destination file name is given, the specified file must not
exist because an existing destination file will not be overwritten.
Any new values for FileName, Directory or HardLink are ignored when
a destination file name is specified.

The destination file name may be undefined to overwrite the original
file (make sure you have backups!). In this case, if a source file
name is provided, a temporary file is created and renamed to replace
the source file if no errors occurred while writing. Otherwise, if
a source file reference or scalar reference is used, the image is
first written to memory then copied back to replace the original if
there were no errors.

On Mac OS systems, the file resource fork is preserved if this
routine is called with a source file name.

GetTagList
Get a sorted list of tags from the specified information hash or tag
list.

@tags = $exifTool->GetTagList($info, 'Group0');

Inputs:
0) ExifTool object reference

1) [optional] Information hash reference or tag list reference

2) [optional] Sort order ('Input', 'File', 'Tag', 'Descr' or
'Group#')

3) [optional] Secondary sort order ('File', 'Tag' or 'Descr')

If the information hash or tag list reference is not provided, then
the list of found tags from the last call to "ImageInfo",
"ExtractInfo" or "GetInfo" is used instead, and the result is the
same as if "GetFoundTags" was called. If sort order is not
specified, the sort order is taken from the current options
settings.

Return Values:
A list of tag keys in the specified order.

GetFoundTags
Get list of found tags in specified sort order. The found tags are the
tags for the information obtained from the most recent call to
"ImageInfo", "ExtractInfo" or "GetInfo" for this object.

@tags = $exifTool->GetFoundTags('File');

Inputs:
0) ExifTool object reference

1) [optional] Sort order ('Input', 'File', 'Tag', 'Descr' or
'Group#')

2) [optional] Secondary sort order ('File', 'Tag' or 'Descr')

If sort order is not specified, the sort order from the ExifTool
options is used.

Return Values:
A list of tag keys in the specified order.

GetRequestedTags
Get list of requested tags. These are the tags that were specified in
the arguments of the most recent call to "ImageInfo", "ExtractInfo" or
"GetInfo", including tags specified via a tag list reference. Shortcut
tags are expanded in the list.

@tags = $exifTool->GetRequestedTags();

Inputs:
(none)

Return Values:
List of requested tag keys in the same order that the tags were
specified. Note that this list will be empty if tags were not
specifically requested (ie. If extracting all tags).

GetValue
Get the value of a specified tag. The returned value is either the
human-readable (PrintConv) value, the converted machine-readable
(ValueConv) value, the original raw (Raw) value, or the original
rational (Rational) value for rational formats. If the value type is
not specified, the PrintConv value is returned if the PrintConv option
is set, otherwise the ValueConv value is returned. The PrintConv values
are same as the values returned by "ImageInfo" and "GetInfo" in the
tag/value hash unless the PrintConv option is disabled.

Tags which represent lists of multiple values (as may happen with
'Keywords' for example) are handled specially. In scalar context, the
returned PrintConv value for these tags is either a string of values or
a list reference (depending on the ListJoin option setting), and the
ValueConv value is always a list reference. But in list context,
"GetValue" always returns the list itself.

Note that "GetValue" requires a case-sensitive tag key as an argument.
To retrieve tag information based on a case-insensitive tag name (with
an optional group specifier), use "GetInfo" instead.

# PrintConv example
my $val = $exifTool->GetValue($tag);
if (ref $val eq 'SCALAR') {
print "$tag = (unprintable value)\n";
} else {
print "$tag = $val\n";
}

# ValueConv examples
my $val = $exifTool->GetValue($tag, 'ValueConv');
if (ref $val eq 'ARRAY') {
print "$tag is a list of values\n";
} elsif (ref $val eq 'SCALAR') {
print "$tag represents binary data\n";
} else {
print "$tag is a simple scalar\n";
}

my @keywords = $exifTool->GetValue('Keywords', 'ValueConv');

Inputs:
0) ExifTool object reference

1) Tag key, or case-sensitive tag name with optional group
prefix(es)

2) [optional] Value type: 'PrintConv', 'ValueConv', 'Both', 'Raw',
'Bin' or 'Rational'

The default value type is 'PrintConv' if the PrintConv option is
set, otherwise the default is 'ValueConv'. A value type of 'Both'
returns both ValueConv and PrintConv values as a list. 'Raw'
returns the raw decoded tag value. 'Bin' returns the original
binary data for EXIF tags if the "SaveBin" option was set.
'Rational' returns the raw rational value as a string fraction for
rational types, or undef for other types.

Return Values:
The value of the specified tag. If the tag represents a list of
multiple values and the ListJoin option is enabled then PrintConv
returns a string of values, otherwise a reference to the list is
returned in scalar context. The list itself is returned in list
context. (Unless 'Both' values are requested, in which case two
list references are returned, regardless of context.) Values may
also be scalar references to binary data, or hash references if the
"Struct" option is set.

Note: It is possible for "GetValue" to return an undefined ValueConv
or PrintConv value (or an empty list in list context) even if the
tag exists, since it is possible for these conversions to yield
undefined values. And the Rational value will be undefined for any
non-rational tag. The Raw value should always exist if the tag
exists.

SetNewValue
Set the new value for a tag. The routine may be called multiple times
to set the values of many tags before using "WriteInfo" to write the new
values to an image. These values remain queued for writing to
subsequent files until "SetNewValue" is called without arguments to
reset the queued values.

For list-type tags (like Keywords), either call repeatedly with the same
tag name for each value, or call with a reference to the list of values.

# set a new value for a tag (errors go to STDERR)
$success = $exifTool->SetNewValue($tag, $value);

# set a new value and capture any error message
($success, $errStr) = $exifTool->SetNewValue($tag, $value);

# delete information for specified tag if it exists in image
# (also resets AddValue and DelValue options for this tag)
$exifTool->SetNewValue($tag);

# reset all values from previous calls to SetNewValue()
$exifTool->SetNewValue();

# delete a specific keyword
$exifTool->SetNewValue('Keywords', $word, DelValue => 1);

# set keywords (a list-type tag) with two new values
$exifTool->SetNewValue(Keywords => 'word1');
$exifTool->SetNewValue(Keywords => 'word2');
# equivalent, but set both in one call using an array reference
$exifTool->SetNewValue(Keywords => ['word1','word2']);

# add a keyword without replacing existing keywords in the file
$exifTool->SetNewValue(Keywords => $word, AddValue => 1);

# conditionally add a tag if it didn't exist before,
# or replace it if it had a specified value ("old value")
$exifTool->SetNewValue(Description => '', DelValue => 1);
$exifTool->SetNewValue(Description => 'old value', DelValue => 1);
$exifTool->SetNewValue(Description => 'new value');

# set a tag in a specific group
$exifTool->SetNewValue(Headline => $val, Group => 'XMP');
$exifTool->SetNewValue('XMP:Headline' => $val); # (equivalent)

# shift original date/time back by 2.5 hours
$exifTool->SetNewValue(DateTimeOriginal => '2:30', Shift => -1);

# write a tag only if it had a specific value
# (the order of the following calls is not significant)
$exifTool->SetNewValue(Title => $oldVal, DelValue => 1);
$exifTool->SetNewValue(Title => $newVal);

# write tag by numerical value
$exifTool->SetNewValue(Orientation => 6, Type => 'ValueConv');
$exifTool->SetNewValue('Orientation#' => 6); # (equivalent)

# delete all but EXIF tags
$exifTool->SetNewValue('*'); # delete all...
$exifTool->SetNewValue('EXIF:*', undef, Replace => 2); # ...but EXIF

# write structured information as a HASH reference
$exifTool->SetNewValue('XMP:Flash' => {
mode => 'on',
fired => 'true',
return => 'not'
});

# write structured information as a serialized string
$exifTool->SetNewValue('XMP:Flash'=>'{mode=on,fired=true,return=not}');

(See <https://exiftool.org/struct.html#Serialize> for a description of
the structure serialization technique.)

Inputs:
0) ExifTool object reference

1) [optional] Tag key or tag name, or undef to clear all new values.
The tag name may be prefixed by one or more family 0, 1 or 2 group
names with optional leading family numbers, separated by colons (eg.
'EXIF:Artist', 'XMP:Time:*'), which is equivalent to using a Group
option argument. Also, a '#' may be appended to the tag name (eg.
'EXIF:Orientation#'), with the same effect as setting Type to
'ValueConv'. Wildcards ('*' and '?') may be used in the tag name to
assign or delete multiple tags simultaneously. A tag name of '*' is
special when deleting information, and will delete an entire group
even if some individual tags in the group are not writable, but only
if a single family 0 or 1 group is specified (otherwise the tags are
deleted individually). Use "GetDeleteGroups" to get a list of
deletable group names, and see Image::ExifTool::TagNames for a
complete list of tag names.

2) [optional] New value for tag. Undefined to delete tag from file.
May be a scalar, scalar reference, list reference to set a list of
values, or hash reference for a structure. Integer values may be
specified as a hexadecimal string (with a leading '0x'), and simple
rational values may be specified in fractional form (eg. '4/10').
Structure tags may be specified either as a hash reference or a
serialized string (see the last two examples above).

3-N) [optional] SetNewValue option/value pairs (see below).

SetNewValue Options:
AddValue
Specifies that the value be added to an existing list in a file
rather than overwriting the existing values. Valid settings are
0 (overwrite any existing tag value), 1 (add to an existing list
and warn for non-list tags) or 2 (add to existing list and
overwrite non-list tags). Default is 0.

DelValue
Delete existing tag from a file if it has the specified value.
For list-type tags this deletes a specified item from the list.
For non-list tags this may be used to conditionally replace a
tag by providing a new value in a separate call to SetNewValue
(see examples above). For structured tags, the entire structure
is deleted/replaced only if all of the specified fields match
the existing structure. Option values are 0 or 1. Default is
0.

EditGroup
Create tags in existing groups only. Don't create new group.
Valid values are 0 and 1. Effectively removes the 'g' from the
ExifTool WriteMode option for this tag only. Default is 0.

EditOnly
Edit tag only if it already exists. Don't create new tag.
Valid values are 0 and 1. Effectively removes the 'c' from the
ExifTool WriteMode option for this tag only. Default is 0.

Group
Specifies group name where tag should be written. This option
is superseded by any group specified in the tag name. If not
specified, tag is written to highest priority group as specified
by "SetNewGroups". May be one or more family 0, 1 or 2 groups
with optional leading family number, separated by colons. Case
is not significant.

NoFlat
Treat flattened tags as 'unsafe'.

NoShortcut
Disables default behaviour of looking up tag in shortcuts if not
found otherwise.

Protected
Bit mask for tag protection levels to write. Bit 0x01 allows
writing of 'unsafe' tags (ie. tags not copied automatically via
"SetNewValuesFromFile"). Bit 0x02 allows writing of 'protected'
tags, and should only be used internally by ExifTool. See
Image::ExifTool::TagNames, for a list of tag names indicating
'unsafe' and 'protected' tags. Default is 0.

ProtectSaved
Avoid setting new values which were saved after the Nth call to
"SaveNewValues". Has no effect on unsaved values, or values
saved before Nth call. Option value is N. Default is undef.

Replace
Flag to replace the previous new values for this tag (ie.
replace the values set in previous calls to "SetNewValue").
This option is most commonly used to replace previously-set new
values for list-type tags. Valid values are 0 (set new value
normally -- adds to new values for list-type tags), 1 (reset any
previous new values before setting new value) or 2 (reset
previous new values only; new value argument is ignored).
Default is 0.

Shift
Shift the tag by the specified value. Currently only date/time
tags and tags with numerical values may be shifted. Undefined
for no shift, 1 for a positive shift, or -1 for a negative
shift. A value of 0 causes a positive shift to be applied if
the tag is shiftable and AddValue is set, or a negative shift
for date/time tags only if DelValue is set. Default is undef.
See Image::ExifTool::Shift(3pm) for more information.

Type
The type of value being set. Valid values are PrintConv,
ValueConv or Raw. Default is PrintConv if the "PrintConv"
Option is set, otherwise ValueConv.

Return Values:
In scalar context, returns the number of tags set and error messages
are printed to STDERR. In list context, returns the number of tags
set, and the error string (which is undefined if there was no
error).

Notes:
When deleting groups of tags, the Replace option may be used to
exclude specific groups from a mass delete. However, this technique
may not be used to exclude individual tags from a group delete
(unless a family 2 group was specified in the delete). Instead, use
"SetNewValuesFromFile" to recover the values of individual tags
after deleting a group.

When deleting all tags from a JPEG image, the APP14 "Adobe"
information is not deleted by default because doing so may affect
the appearance of the image. However, this information may be
deleted by specifying it explicitly, either by group (with
'Adobe:*') or as a block (with 'Adobe').

GetNewValue
Get the new Raw value for a tag. This is the value set by "SetNewValue"
this is queued to be written to file. List-type tags may return
multiple values in list context.

$rawVal = $exifTool->GetNewValue($tag);

@rawVals = $exifTool->GetNewValue($tag);

Notes:
The API NoDups option applies when this routine is called, and
removes duplicate items from values returned for List-type tags.

Inputs:
0) ExifTool object reference

1) Tag name (case sensitive, may be prefixed by family 0, 1 or 7
group names, separated by colons)

Return Values:
List of new Raw tag values, or first value in list when called in
scalar context. The list may be empty either if the tag isn't being
written, or if it is being deleted (ie. if "SetNewValue" was called
without a value).

SetNewValuesFromFile
A very powerful routine that sets new values for tags from information
found in a specified file.

# set new values from all information in a file...
my $info = $exifTool->SetNewValuesFromFile($srcFile);
# ...then write these values to another image
my $result = $exifTool->WriteInfo($file2, $outFile);

# set all new values, preserving original groups
$exifTool->SetNewValuesFromFile($srcFile, '*:*');

# set specific information
$exifTool->SetNewValuesFromFile($srcFile, @tags);

# set new value from a different tag in specific group
$exifTool->SetNewValuesFromFile($fp, 'XMP-dc:Subject<IPTC:Keywords');

# add all IPTC keywords to XMP subject list
$exifTool->SetNewValuesFromFile($fp, 'XMP-dc:Subject+<IPTC:Keywords');

# set new value from an expression involving other tags
$exifTool->SetNewValuesFromFile($file,
'Comment<ISO=$ISO Aperture=$aperture Exposure=$shutterSpeed');

# set keywords list from the values of multiple tags
$exifTool->SetNewValuesFromFile($file, { Replace => 0 },
'keywords<xmp:subject', 'keywords<filename');

# copy all EXIF information, preserving the original IFD
# (without '*.*<' tags would be copied to the preferred EXIF IFD)
$exifTool->SetNewValuesFromFile($file, '*:*<EXIF:*');

# copy all tags with names starting with "gps" (note: this is
# different than "gps:*" because it will also copy XMP GPS tags)
$exifTool->SetNewValuesFromFile($file, 'gps*');

# set FileName from Model, translating questionable characters
$exifTool->SetNewValuesFromFile($file,
'filename<${model; tr(/\\\\?*:|"><)(_) }.jpg');

Inputs:
0) ExifTool object reference

1) File name, file reference, or scalar reference

2-N) [optional] List of tag names to set or options hash references.
All writable tags are set if none are specified. The tag names are
not case sensitive, and may be prefixed by one or more family 0, 1,
2 or 7 group names with optional leading family numbers, separated
by colons (eg. 'exif:iso'). A leading '-' indicates tags to be
excluded (eg. '-comment'), or a trailing '#' causes the ValueConv
value to be copied (same as setting the Type option to 'ValueConv'
for this tag only). A leading '+' sets the Replace option to 0 on a
per-tag basis (see Options below). Wildcards ('*' and '?') may be
used in the tag name. A tag name of '*' is commonly used when a
group is specified to copy all tags in the group (eg. 'XMP:*').

A special feature allows tag names of the form 'DSTTAG<SRCTAG' (or
'SRCTAG>DSTTAG') to be specified to copy information to a tag with a
different name or a specified group. Both 'SRCTAG' and 'DSTTAG' may
contain wildcards and/or be prefixed by a group name (eg.
'fileModifyDate<modifyDate' or 'xmp:*<*'), and/or suffixed by a '#'
to disable print conversion. Copied tags may also be added or
deleted from a list with arguments of the form 'DSTTAG+<SRCTAG' or
'DSTTAG-<SRCTAG'. Tags are evaluated in order, so exclusions apply
only to tags included earlier in the list. An extension of this
feature allows the tag value to be set from a string containing tag
names with leading '$' symbols (eg. 'Comment<the file is
$filename'). Braces '{}' may be used around a tag name to separate
it from subsequent text, and a '$$' is used to to represent a '$'
symbol. The behaviour for missing tags in expressions is defined by
the "MissingTagValue" option. The tag value may be modified via
changes to the default input variable ($_) in a Perl expression
placed inside the braces and after a semicolon following the tag
name (see the last example above). A '@' may be added after the tag
name (before the semicolon) to make the expression act on individual
list items instead of the concatenated string for list-type tags.
The expression has access to the full ExifTool API through the
current ExifTool object ($self) and the tag key ($tag). Braces
within the expression must be balanced.

Multiple options hash references may be passed to set different
options for different tags. Options apply to subsequent tags in the
argument list.

By default, this routine will commute information between same-named
tags in different groups, allowing information to be translated
between images with different formats. This behaviour may be
modified by specifying a group name for extracted tags (even if '*'
is used as a group name), in which case the information is written
to the original group, unless redirected to a different group. When
'*' is used for a group name, by default the family 1 group of the
original tag is preserved, but a different family may be specified
with a leading family number. (For example, specifying '*:*' copies
all information while preserving the original family 1 groups, while
'0*:*' preserves the family 0 group.)

SetNewValuesFromFile Options:
The options are the same was for "SetNewValue", and are passed
directly to "SetNewValue" internally, with a few exceptions:

- The Replace option defaults to 1 instead of 0 as with
"SetNewValue", however the tag name argument may be prefixed with
'+' to set the Replace option to 0 for this argument only.

- The AddValue or DelValue option is set for individual tags if '+>'
or '->' (or '+<' or '-<') are used.

- The Group option is set for tags where a group name is given.

- The Protected flag is set to 1 for individually specified tags.

- The Type option also applies to extracted tags.

Return Values:
A hash of information that was set successfully. May include
Warning or Error entries if there were problems reading the input
file.

Notes:
The PrintConv option applies to this routine, but it normally should
be left on to provide more reliable transfer of information between
groups.

If a preview image exists, it is not copied. The preview image must
be transferred separately if desired, in a separate call to
"WriteInfo"

When simply copying all information between files of the same type,
it is usually desirable to preserve the original groups by
specifying '*:*' for the tags to set.

The "Duplicates" option is always in effect for tags extracted from
the source file using this routine.

The "Struct" option is enabled by default for tags extracted by this
routine. This allows the hierarchy of complex structures to be
preserved when copying, but the Struct option may be set to 0 to
override this behaviour and copy as flattened tags instead.

CountNewValues
Return the total number of new values set.

$numSet = $exifTool->CountNewValues();
($numSet, $numPseudo) = $exifTool->CountNewValues();

Inputs:
0) ExifTool object reference

Return Values:
In scalar context, returns the total number of tags with new values
set. In list context, also returns the number of "pseudo" tag
values which have been set. "Pseudo" tags are tags like FileName
and FileModifyDate which are not contained within the file and can
be changed without rewriting the file.

SaveNewValues
Save state of new values to be later restored by "RestoreNewValues".

$exifTool->SaveNewValues(); # save state of new values
$exifTool->SetNewValue(ISO => 100); # set new value for ISO
$exifTool->WriteInfo($src, $dst1); # write ISO + previous new values
$exifTool->RestoreNewValues(); # restore previous new values
$exifTool->WriteInfo($src, $dst2); # write previous new values only

Inputs:
0) ExifTool object reference

Return Value:
Count of the number of times this routine has been called (N) since
the last time the new values were reset.

RestoreNewValues
Restore new values to the settings that existed when "SaveNewValues" was
last called. May be called repeatedly after a single call to
"SaveNewValues". See "SaveNewValues" above for an example.

Inputs:
0) ExifTool object reference

Return Value:
None.

SetAlternateFile
Specify alternate file from which to read metadata. Tags from the
alternate file are available after "ExtractInfo" is called or during a
call to "SetNewValuesFromFile" by using a family 8 group name (eg.
'File1' in the example below).

$exifTool->SetAlternateFile(File1 => 'images/test1.jpg');

Inputs:
0) ExifTool object reference

1) Family 8 group name, case insensitive (eg. 'File1', 'File2'...)

2) Name of alternate input file, or undef to reset

Return Values:
1 on success, or 0 if the group name is invalid.

SetFileModifyDate
Write the filesystem modification or creation time from the new value of
the FileModifyDate or FileCreateDate tag.

$exifTool->SetNewValue(FileModifyDate => '2000:01:02 03:04:05-05:00',
Protected => 1);
$result = $exifTool->SetFileModifyDate($file);

Inputs:
0) ExifTool object reference

1) File name

2) [optional] Base time if applying shift (days before $^T)

3) [optional] Tag to write: 'FileModifyDate' (default), or
'FileCreateDate'

Return Value:
1 if the time was changed, 0 if nothing was done, or -1 if there was
an error setting the time.

Notes:
Equivalent to, but more efficient than calling "WriteInfo" when only
the FileModifyDate or FileCreateDate tag has been set. If a
timezone is not specified, local time is assumed. When shifting,
the time of the original file is used unless the optional base time
is specified.

The ability to write FileCreateDate is currently restricted to
Windows systems only.

SetFileName
Set the file name and directory, or create a hard link. If not
specified, the new file name is derived from the new values of the
FileName and Directory tags, or from the HardLink or SymLink tag if
creating a link. If the FileName tag contains a '/', then the file is
renamed into a new directory. If FileName ends with '/', then it is
taken as a directory name and the file is moved into the new directory.
The new value for the Directory tag takes precedence over any directory
specified in FileName.

$result = $exifTool->SetFileName($file);
$result = $exifTool->SetFileName($file, $newName);

Inputs:
0) ExifTool object reference

1) Current file name

2) [optional] New file name

3) [optional] 'HardLink' or 'SymLink' to create a hard or symbolic
link instead of renaming the file, or 'Test' to test renaming
feature by printing the old and new names instead of changing
anything.

Return Value:
1 on success, 0 if nothing was done, or -1 if there was an error
renaming the file or creating the link.

Notes:
Will not overwrite existing files. New directories are created as
necessary. If the file is successfully renamed, the new file name
may be accessed via $$exifTool{NewName}.

SetNewGroups
Set the order of the preferred groups when adding new information. In
subsequent calls to "SetNewValue", new information will be created in
the first valid group of this list. This has an impact only if the
group is not specified when calling "SetNewValue" and if the tag name
exists in more than one group. The default order is EXIF, IPTC, XMP,
MakerNotes, QuickTime, Photoshop, ICC_Profile, CanonVRD, Adobe. Any
family 0 group name may be used. Case is not significant.

$exifTool->SetNewGroups('XMP','EXIF','IPTC');

Inputs:
0) ExifTool object reference

1-N) Groups in order of priority. If no groups are specified, the
priorities are reset to the defaults.

Return Value:
None.

GetNewGroups
Get current group priority list.

@groups = $exifTool->GetNewGroups();

Inputs:
0) ExifTool object reference

Return Values:
List of group names in order of write priority. Highest priority
first.

GetTagID
Get the ID for the specified tag. The ID is the IFD tag number in EXIF
information, the property name in XMP information, or the data offset in
a binary data block. For some tags, such as Composite tags where there
is no ID, an empty string is returned. In list context, also returns a
language code for the tag if available and different from the default
language (eg. with alternate language entries for XMP "lang-alt" tags).

$id = $exifTool->GetTagID($tag);
($id, $lang) = $exifTool->GetTagID($tag);

Inputs:
0) ExifTool object reference

1) Tag key

Return Values:
In scalar context, returns the tag ID or '' if there is no ID for
this tag. In list context, returns the tag ID (or '') and the
language code (or undef).

GetDescription
Get description for specified tag. This function will always return a
defined value. In the case where the description doesn't exist, one is
generated from the tag name.

Inputs:
0) ExifTool object reference

1) Tag key

Return Values:
A description for the specified tag.

GetGroup
Get group name(s) for a specified tag.

# return family 0 group name (eg. 'EXIF');
$group = $exifTool->GetGroup($tag, 0);

# return all groups (eg. qw{EXIF IFD0 Author Main})
@groups = $exifTool->GetGroup($tag);

# return groups as a string (eg. 'Main:IFD0:Author')
$group = $exifTool->GetGroup($tag, ':3:1:2');

# return groups as a simplified string (eg. 'IFD0:Author')
$group = $exifTool->GetGroup($tag, '3:1:2');

Inputs:
0) ExifTool object reference

1) Tag key

2) [optional] Group family number, or string of numbers separated by
colons

Return Values:
Group name (or '' if tag has no group). If no group family is
specified, "GetGroup" returns the name of the group in family 0 when
called in scalar context, or the names of groups for all families in
list context. Returns a string of group names separated by colons
if the input group family contains a colon. The string is
simplified to remove a leading 'Main:' and adjacent identical group
names unless the family string begins with a colon.

Notes:
The group family numbers are currently available:

0) Information Type (eg. EXIF, XMP, IPTC)
1) Specific Location (eg. IFD0, XMP-dc)
2) Category (eg. Author, Time)
3) Document Number (eg. Main, Doc1, Doc3-2)
4) Instance Number (eg. Copy1, Copy2, Copy3...)
5) Metadata Path (eg. JPEG-APP1-IFD0-ExifIFD)
6) EXIF/TIFF Format (eg. int8u, int32u, undef, string)
7) Tag ID (eg. ID-271, ID-rights, ID-a9aut)
8) Alternate File Number (eg. File1, File2, File3...)

Families 0 and 1 are based on the file structure, and are similar
except that family 1 is more specific and sub-divides some groups to
give more detail about the specific location where the information
was found. For example, the EXIF group is split up based on the
specific IFD (Image File Directory), the MakerNotes group is divided
into groups for each manufacturer, and the XMP group is separated
based on the XMP namespace prefix. Note that only common XMP
namespaces are listed in the GetAllGroups documentation, but
additional namespaces may be present in some XMP data. Also note
that the 'XMP-xmp...' group names may appear in the older form
'XMP-xap...' since these names evolved as the XMP standard was
developed. The ICC_Profile group is broken down to give information
about the specific ICC_Profile tag from which multiple values were
extracted. As well, information extracted from the ICC_Profile
header is separated into the ICC-header group.

Family 2 classifies information based on the logical category to
which the information refers.

Family 3 gives the document number for tags extracted from embedded
documents, or 'Main' for tags from the main document. (See the
"ExtractEmbedded" option for extracting tags from embedded
documents.) Nested sub-documents (if they exist) are indicated by
numbers separated with dashes in the group name, to an arbitrary
depth. (eg. 'Doc2-3-1' is the 1st sub-sub-document of the 3rd sub-
document of the 2nd embedded document of the main file.) Document
numbers are also used to differentiate samples for timed metadata in
videos.

Family 4 provides a method for differentiating tags when multiple
tags exist with the same name in the same location. The primary
instance of a tag (the tag extracted when the Duplicates option is
disabled and no group is specified) has no family 4 group name, but
additional instances have family 4 group names of 'Copy1', 'Copy2',
'Copy3', etc. For convenience, the primary tag may also be accessed
using a group name of 'Copy0'.

Family 5 is experimental, and gives the complete path for the
metadata in the file. Generated only if the "SavePath" option is
used when extracting.

Family 6 is currently used only for EXIF/TIFF metadata, and gives
the format type of the extracted value. Generated only if the
"SaveFormat" option is used when extracting.

Family 7 is used for tag ID's. The group names are the actual tag
ID's, with a leading "ID-" string. Non-numerical ID's have
characters other than [-_A-Za-z0-9] converted to hex. Numerical tag
ID's are returned in hex if the "HexTagIDs" option is set, otherwise
decimal is used. When specifying a family 7 group name, numerical
ID's may be in hex or decimal, and non-numerical ID's may or may not
have characters other than [-_A-Za-z0-9] converted to hex. Note
that unlike other group names, the tag ID's of family 7 group names
are case sensitive (but the leading "ID-" is not).

Family 8 specifies the alternate file set from a call to
"SetAlternateFile".

See "GetAllGroups [static]" for complete lists of group names.

GetGroups
Get list of group names that exist in the specified information.

@groups = $exifTool->GetGroups($info, 2);
@groups = $exifTool->GetGroups('3:1');

Inputs:
0) ExifTool object reference

1) [optional] Info hash ref (default is all extracted info)

2) [optional] Group family number, or string of numbers (default 0)

Return Values:
List of group names in alphabetical order. If information hash is
not specified, the group names are returned for all extracted
information. See "GetGroup" for an description of family numbers and
family number strings.

BuildCompositeTags
Builds composite tags from required tags. The composite tags are
convenience tags which are derived from the values of other tags. This
routine is called automatically by "ImageInfo" and "ExtractInfo" if the
Composite option is set.

Inputs:
0) ExifTool object reference

Return Values:
(none)

Notes:
Tag values are calculated in alphabetical order unless a tag
Require's or Desire's another composite tag, in which case the
calculation is deferred until after the other tag is calculated.

Composite tags may need to read data from the image for their value
to be determined, and for these "BuildCompositeTags" must be called
while the image is available. This is only a problem if "ImageInfo"
is called with a filename (as opposed to a file reference or scalar
reference) since in this case the file is closed before "ImageInfo"
returns. Here the Composite option may be used so that
"BuildCompositeTags" is called from within "ImageInfo", before the
file is closed.

AvailableOptions [static]
Get a list of available API options. (See "Options" for option details.)

Inputs:
(none)

Return Values:
Reference to list of available options. Each entry in the list is a
list reference with 4 items: 0=Option name, 1=Default value,
2=Description, 3=flag set if option is undocumented.

my $opts = Image::ExifTool::<b>AvailableOptions</b>();
foreach (@$opts) {
my ($optionName, $defaultValue, $description) = @$_;
...
}

GetTagName [static]
Get name of tag from tag key. This is a convenience function that
strips the embedded instance number, if it exists, from the tag key.

Note: "static" in the heading above indicates that the function does not
require an ExifTool object reference as the first argument. All
functions documented below are also static.

$tagName = Image::ExifTool::GetTagName($tag);

Inputs:
0) Tag key

Return Value:
Tag name. This is the same as the tag key but has the instance
number removed.

GetShortcuts [static]
Get a list of shortcut tags.

Inputs:
(none)

Return Values:
List of shortcut tags (as defined in Image::ExifTool::Shortcuts).

GetAllTags [static]
Get list of all available tag names.

@tagList = Image::ExifTool::GetAllTags($group);

Inputs:
0) [optional] Group name, or string of group names separated by
colons

Return Values:
A list of all available tags in alphabetical order, or all tags in a
specified group or intersection of groups. The group name is case
insensitive, and any group in families 0-2 may be used except for
EXIF family 1 groups (ie. the specific IFD).

GetWritableTags [static]
Get list of all writable tag names.

@tagList = Image::ExifTool::GetWritableTags($group);

Inputs:
0) [optional] Group name, or string of group names separated by
colons

Return Values:
A list of all writable tags in alphabetical order. These are the
tags for which values may be set through "SetNewValue". If a group
name is given, returns only writable tags in specified group(s).
The group name is case insensitive, and any group in families 0-2
may be used except for EXIF family 1 groups (ie. the specific IFD).

GetAllGroups [static]
Get list of all group names in specified family.

@groupList = Image::ExifTool::GetAllGroups($family);

Inputs:
0) Group family number (0-7)

Return Values:
A list of all groups in the specified family in alphabetical order.

Here is a complete list of groups for each of these families:

Family 0 (Information Type):
AAC, AFCP, AIFF, APE, APP0, APP1, APP11, APP12, APP13, APP14, APP15,
APP2, APP3, APP4, APP5, APP6, APP7, APP8, APP9, ASF, Audible, Canon,
CanonVRD, Composite, DICOM, DjVu, DNG, Ducky, DV, EXE, EXIF,
ExifTool, File, FITS, FLAC, Flash, FlashPix, FLIR, Font,
FotoStation, GeoTiff, GIF, GIMP, GM, GoPro, H264, HTML, ICC_Profile,
ID3, IPTC, ISO, ITC, JFIF, JPEG, Jpeg2000, JSON, JUMBF, Leaf, LNK,
Lytro, M2TS, MakerNotes, Matroska, Meta, MIE, MIFF, MISB, MNG, MOI,
MPC, MPEG, MPF, MXF, Ogg, OpenEXR, Opus, Palm, PanasonicRaw, Parrot,
PDF, PhotoCD, PhotoMechanic, Photoshop, PICT, PLIST, PNG,
PostScript, PrintIM, Protobuf, PSP, QuickTime, Radiance, RAF,
Rawzor, Real, Red, RIFF, RSRC, RTF, SigmaRaw, Sony, Stim, SVG,
Theora, Torrent, Trailer, VCard, Vorbis, WTV, XML, XMP, ZIP

Family 1 (Specific Location):
AAC, AC3, Adobe, AdobeCM, AdobeDNG, AFCP, AIFF, APE, APP10, APP2,
Apple, ASF, Audible, AudioItemList, AudioKeys, AudioUserData, AVI1,
CameraIFD, Canon, CanonCustom, CanonDR4, CanonRaw, CanonVRD, Casio,
CBOR, Chapter#, CIFF, Composite, DICOM, DJI, DjVu, DjVu-Meta, DNG,
Ducky, DV, EPPIM, EXE, EXIF, ExifIFD, ExifTool, File, FITS, FLAC,
Flash, FlashPix, FLIR, Font, FotoStation, FujiFilm, FujiIFD, Garmin,
GE, GeoTiff, GIF, GIMP, GlobParamIFD, GM, Google, GoPro, GPS,
GraphConv, GSpherical, H264, HP, HTC, HTML, HTML-dc, HTML-ncc, HTML-
office, HTML-prod, HTML-vw96, HTTP-equiv, ICC-chrm, ICC-cicp, ICC-
clrt, ICC-header, ICC-meas, ICC-meta, ICC-view, ICC_Profile,
ICC_Profile#, ID3, ID3v1, ID3v1_Enh, ID3v2_2, ID3v2_3, ID3v2_4,
IFD0, IFD1, InfiRay, Insta360, InteropIFD, IPTC, IPTC#, ISO, ITC,
ItemList, iTunes, JFIF, JFXX, JPEG, JPEG-HDR, Jpeg2000, JPS, JSON,
JUMBF, JVC, KDC_IFD, Keys, Kodak, KodakBordersIFD, KodakEffectsIFD,
KodakIFD, KyoceraRaw, Leaf, LeafSubIFD, Leica, LNK, Lyrics3, Lytro,
M-RAW, M2TS, MAC, MacOS, MakerNotes, MakerUnknown, Matroska,
MediaJukebox, Meta, MetaIFD, Microsoft, MIE-Audio, MIE-Camera, MIE-
Canon, MIE-Doc, MIE-Extender, MIE-Flash, MIE-Geo, MIE-GPS, MIE-
Image, MIE-Lens, MIE-Main, MIE-MakerNotes, MIE-Meta, MIE-Orient,
MIE-Preview, MIE-Thumbnail, MIE-Unknown, MIE-UTM, MIE-Video, MIFF,
Minolta, MinoltaRaw, MISB, MNG, MOBI, MOI, Motorola, MPC, MPEG,
MPF0, MPImage, MS-DOC, MXF, Nextbase, Nikon, NikonCapture,
NikonCustom, NikonScan, NikonSettings, NineEdits, Nintendo, NITF,
Ocad, Ogg, Olympus, OnePlus, OpenEXR, Opus, Palm, Panasonic,
PanasonicRaw, Parrot, PDF, Pentax, PhaseOne, PhotoCD, PhotoMechanic,
Photoshop, PICT, PictureInfo, PNG, PNG-cICP, PNG-pHYs, PostScript,
PreviewIFD, PrintIM, ProfileIFD, PSP, Qualcomm, QuickTime, Radiance,
RAF, RAF2, Rawzor, Real, Real-CONT, Real-MDPR, Real-PROP, Real-RA3,
Real-RA4, Real-RA5, Real-RJMD, Reconyx, Red, Ricoh, RIFF, RMETA,
RSRC, RTF, Samsung, Sanyo, Scalado, SEAL, Sigma, SigmaRaw, Sony,
SonyIDC, SPIFF, SR2, SR2DataIFD, SR2SubIFD, SRF#, Stim, SubIFD, SVG,
System, Theora, Torrent, Track#, Track#ItemList, Track#Keys,
Track#UserData, UserData, VCalendar, VCard, Version0, VideoItemList,
VideoKeys, VideoUserData, Vivo, VNote, Vorbis, WTV, XML, XMP, XMP-
aas, XMP-acdsee, XMP-acdsee-rs, XMP-album, XMP-apdi, XMP-apple-fi,
XMP-ast, XMP-aux, XMP-cc, XMP-cell, XMP-crd, XMP-creatorAtom, XMP-
crs, XMP-dc, XMP-Device, XMP-dex, XMP-DICOM, XMP-digiKam, XMP-drone-
dji, XMP-dwc, XMP-et, XMP-exif, XMP-exifEX, XMP-expressionmedia,
XMP-extensis, XMP-fpv, XMP-GAudio, XMP-GCamera, XMP-GContainer, XMP-
GCreations, XMP-GDepth, XMP-getty, XMP-GFocus, XMP-GImage, XMP-
GPano, XMP-GSpherical, XMP-hdr, XMP-HDRGainMap, XMP-hdrgm, XMP-ics,
XMP-iptcCore, XMP-iptcExt, XMP-LImage, XMP-lr, XMP-mediapro, XMP-
microsoft, XMP-MP, XMP-MP1, XMP-mwg-coll, XMP-mwg-kw, XMP-mwg-rs,
XMP-nine, XMP-panorama, XMP-pdf, XMP-pdfx, XMP-photomech, XMP-
photoshop, XMP-PixelLive, XMP-plus, XMP-pmi, XMP-prism, XMP-prl,
XMP-prm, XMP-pur, XMP-rdf, XMP-sdc, XMP-seal, XMP-swf, XMP-tiff,
XMP-x, XMP-xmp, XMP-xmpBJ, XMP-xmpDM, XMP-xmpDSA, XMP-xmpMM, XMP-
xmpNote, XMP-xmpPLUS, XMP-xmpRights, XMP-xmpTPg, ZIP

Family 2 (Category):
Audio, Author, Camera, Device, Document, ExifTool, Image, Location,
Other, Preview, Printing, Time, Unknown, Video

Family 3 (Document Number):
Doc#, Main

Family 4 (Instance Number):
Copy#

Family 5 (Metadata Path):
eg. JPEG-APP1-IFD0-ExifIFD

Family 6 (EXIF/TIFF Format):
int8u, string, int16u, int32u, rational64u, int8s, undef, int16s,
int32s, rational64s, float, double, ifd, unicode, complex, int64u,
int64s, ifd64

Family 7 (Tag ID):
ID-xxx (Where xxx is the tag ID. Numerical ID's are returned in hex
with a leading "0x" if the HexTagIDs option is set, or decimal
otherwise. Characters in non-numerical ID's which are not valid in
a group name are returned as 2 hex digits.)

Family 8 (Alternate File):
File#

Note: This function may also be called as an ExifTool member function
to allow the HexTagIDs option to be set when retrieving family 7 group
names.

GetDeleteGroups [static]
Get list of all deletable group names.

@delGroups = Image::ExifTool::GetDeleteGroups();

Inputs:
None.

Return Values:
A list of deletable group names in alphabetical order. The current
list of deletable group names is:

Adobe, AFCP, APP0, APP1, APP10, APP11, APP12, APP13, APP14, APP15,
APP2, APP3, APP4, APP5, APP6, APP7, APP8, APP9, Audio, Author,
Camera, CanonVRD, CIFF, Document, Ducky, EXIF, ExifIFD, ExifTool,
File, FlashPix, FotoStation, GlobParamIFD, GPS, ICC_Profile, IFD0,
IFD1, Image, Insta360, InteropIFD, IPTC, ItemList, JFIF, Jpeg2000,
Keys, Location, MakerNotes, Meta, MetaIFD, Microsoft, MIE, MPF,
NikonCapture, Other, PDF, PDF-update, PhotoMechanic, Photoshop, PNG,
PNG-pHYs, Preview, PrintIM, Printing, QuickTime, RMETA, RSRC,
SubIFD, Time, Trailer, UserData, Video, XML, XML-*, XMP, XMP-*

To schedule a group for deletion, call "SetNewValue" with a tag name
like 'EXIF:*' and an undefined tag value.

Deleting a family 0 or 1 group will delete the entire corresponding
block of metadata, but deleting a family 2 group (eg. Audio, Author,
Camera, etc.) deletes the individual tags belonging to that
category.

The 'Trailer' group allows all trailers in JPEG and TIFF-format
images to be deleted at once, including unknown trailers. Note that
the JPEG "APP" groups are special, and are used only to delete
application segments which are not associated with another deletable
group. For example, deleting 'APP14:*' will delete other APP14
segments, but not the APP14 "Adobe" segment.

GetFileType [static]
Get type of file given file name.

my $type = Image::ExifTool::GetFileType($filename);
my $desc = Image::ExifTool::GetFileType($filename, 1);

Inputs:
0) [optional] File name (or just an extension)

1) [optional] Flag to return a description instead of a type.
Default is undef. Set to 0 to also return types of recognized but
unsupported files (otherwise the return value for unsupported files
is undef), or 1 to return descriptions.

Return Value:
A string, based on the file extension, which indicates the basic
format of the file. Note that some files may be based on other
formats (like many RAW image formats are based on TIFF). In list
context, may return more than one file type if the file may be based
on different formats. Returns undef if files with this extension
are not yet supported by ExifTool. Returns a list of extensions for
all supported file types if no input extension is specified (or all
recognized file types if the description flag is set to 0). Returns
a more detailed description of the specific file format when the
description flag is set.

CanWrite [static]
Can the specified file be written?

my $writable = Image::ExifTool::CanWrite($filename);

Inputs:
0) File name or extension

Return Value:
True if ExifTool supports writing files of this type (based on the
file extension).

CanCreate [static]
Can the specified file be created?

my $creatable = Image::ExifTool::CanCreate($filename);

Inputs:
0) File name or extension

Return Value:
True if ExifTool can create files with this extension from scratch.
Currently, this can only be done with XMP, MIE, ICC, VRD, DR4, EXV
and EXIF files.

AddUserDefinedTags [static]
Add user-defined tags to an existing tag table at run time. This
differs from the usual technique of creating user-defined tags via the
%Image::ExifTool::UserDefined hash (see the ExifTool_config file in the
Image::ExifTool distribution) because it allows tags to be added after a
tag table has been initialized.

use Image::ExifTool ':Public';
my %tags = (
TestTagID1 => { Name => 'TestTagName1' },
TestTagID2 => { Name => 'TestTagName2' },
);
my $num = AddUserDefinedTags('Image::ExifTool::PDF::Info', %tags);

Inputs:
0) Destination tag table name

1-N) Pairs of tag ID / tag information hash references for the new
tags

Return Value:
The number of tags added.

Notes
Pre-existing tags with the same ID will be replaced in the
destination table. See lib/Image/ExifTool/README in the full
distribution for full details on the elements of the tag information
hash.

OrderedKeys [static]
Return a list of ordered keys from a tag value that is a HASH reference
when the Struct option is used.

use Image::ExifTool ':Public';
my @keys = OrderedKeys($structRef);

Inputs:
0) Structure HASH reference

Return Value:
List of ordered keys, or sorted alphabetically if not ordered.

CHARACTER ENCODINGS
Certain meta information formats allow coded character sets other than
plain ASCII. When reading, most known encodings are converted to the
external character set according to the "Charset" option, or to UTF-8 by
default. When writing, the inverse conversions are performed.
Alternatively, special characters may be converted to/from HTML
character entities with the "Escape" HTML option.

A distinction is made between the external character set visible via the
ExifTool API, and the internal character used to store text in the
metadata of a file. These character sets may be specified separately as
follows:

External Character Sets:
The encoding for tag values passed to/from ExifTool API functions is
set via the "Charset" option, which is 'UTF8' by default.

The encoding of file names is specified via the "CharsetFileName"
option. By default, "CharsetFileName" is not defined, and file
names passed to ExifTool are used directly in calls to the system
i/o routines (which expect UTF-8 strings on Mac/Linux, but default
to the system code page on Windows). In this mode on Windows a
warning is issued if a file name contains special characters, but
this warning may be avoided by setting "CharsetFileName" to an empty
string. Setting "CharsetFileName" to any other value causes file
names to be converted from the specified encoding to one appropriate
for the system. In Windows this also has the effect of activating
Unicode filename support via the special Windows wide-character i/o
routines if Win32API::File is available.

Note that setting the "WindowsWideFile" or "WindowsLongPath" option
causes "CharsetFileName" to default to 'UTF8' in Windows if not
defined, and "WindowsLongPath" is set by default in ExifTool 13.07
and later.

Internal Character Sets:
The encodings used to store strings in the various metadata formats.
These encodings may be changed for certain types of metadata via the
"CharsetEXIF", "CharsetID3", "CharsetIPTC", "CharsetPhotoshop",
"CharsetQuickTime" and "CharsetRIFF" options.

Values are returned as byte strings of encoded characters. Perl wide
characters are not used. By default, most returned strings are encoded
in UTF-8. For these, Encode::decode_utf8() may be used to convert to a
sequence of logical Perl characters. Note that some settings of the
PERL_UNICODE environment variable may be incompatible with ExifTool's
character handling.

More specific details are given below about how character coding is
handled for EXIF, IPTC, XMP, PNG, ID3, PDF, Photoshop, QuickTime, AIFF,
MIE and Vorbis information:

EXIF
Most textual information in EXIF is stored in ASCII format (called
"string" in the ExifTool tag name documentation). By default ExifTool
does not convert these strings. However, it is not uncommon for
applications to write UTF-8 or other encodings where ASCII is expected.
To deal with these, ExifTool allows the internal EXIF string encoding to
be specified with "CharsetEXIF", which causes EXIF string values to be
converted from the specified character set when reading, and stored with
this character set when writing. (The MWG recommends using UTF-8
encoding for EXIF strings, and in keeping with this the MWG module sets
the default internal EXIF string encoding to UTF-8, but note that this
will have no effect unless the external encoding is also set to
something other than the default of UTF-8.)

A few EXIF tags (UserComment, GPSProcessingMethod and
GPSAreaInformation) support a designated internal text encoding, with
values stored as ASCII, Unicode (UCS-2) or JIS. When reading these
tags, ExifTool converts Unicode and JIS to the external character set
specified by the "Charset" option, or to UTF-8 by default. ASCII text
is not converted. When writing, text is stored as ASCII unless the
string contains special characters, in which case it is converted from
the external character set (UTF-8 by default), and stored as Unicode.
ExifTool writes Unicode in native EXIF byte ordering by default, but the
byte order may be specified by setting the ExifUnicodeByteOrder tag (see
the Extra Tags documentation).

The EXIF "XP" tags (XPTitle, XPComment, etc) are always stored as
little-endian Unicode (UCS-2), and are read and written using the
specified character set.

IPTC
The value of the IPTC:CodedCharacterSet tag determines how the internal
IPTC string values are interpreted. If CodedCharacterSet exists and has
a value of 'UTF8' (or 'ESC % G') then string values are assumed to be
stored as UTF-8, otherwise Windows Latin1 (cp1252, 'Latin') coding is
assumed by default, but this can be changed with the "CharsetIPTC"
option. When reading, these strings are converted to the character set
specified by the "Charset" option. When writing, the inverse
conversions are performed. No conversion is done if the internal (IPTC)
and external (ExifTool) character sets are the same. Note that ISO 2022
character set shifting is not supported. Instead, a warning is issued
and the string is not converted if an ISO 2022 shift code is
encountered. See <http://www.iptc.org/IIM/> for the official IPTC
specification.

ExifTool may be used to convert IPTC values to a different internal
encoding. To do this, all IPTC tags must be rewritten along with the
desired value of CodedCharacterSet. For example, the following command
changes the internal IPTC encoding to UTF-8 (from Windows Latin1 unless
CodedCharacterSet was already 'UTF8'):

exiftool -tagsfromfile @ -iptc:all -codedcharacterset=utf8 a.jpg

or from Windows Latin2 (cp1250) to UTF-8:

exiftool -tagsfromfile @ -iptc:all -codedcharacterset=utf8 \
-charset iptc=latin2 a.jpg

and this command changes it back from UTF-8 to Windows Latin1 (cp1252):

exiftool -tagsfromfile @ -iptc:all -codedcharacterset= a.jpg

or to Windows Latin2:

exiftool -tagsfromfile @ -iptc:all -codedcharacterset= \
-charset iptc=latin2 a.jpg

Unless CodedCharacterSet is 'UTF8', applications have no reliable way to
determine the IPTC character encoding. For this reason, it is
recommended that CodedCharacterSet be set to 'UTF8' when creating new
IPTC.

(Note: Here, "IPTC" Refers to the older IPTC IIM format. The more
recent IPTC Core and Extension specifications actually use the XMP
format.)

XMP
ExifTool reads XMP encoded as UTF-8, UTF-16 or UTF-32, and converts them
all to UTF-8 internally. Also, all XML character entity references and
numeric character references are converted. When writing, ExifTool
always encodes XMP as UTF-8, converting the following 5 characters to
XML character references: & < > ' ". By default no further conversion
is performed, however if the "Charset" option is other than 'UTF8' then
text is converted to/from the specified character set when
reading/writing.

PNG
PNG TextualData tags are stored as tEXt, zTXt and iTXt chunks in PNG
images. The tEXt and zTXt chunks use ISO 8859-1 encoding, while iTXt
uses UTF-8. When reading, ExifTool converts all PNG textual data to the
character set specified by the "Charset" option. When writing, ExifTool
generates a tEXt chunk (or zTXt with the "Compress" option) if the text
doesn't contain special characters or if Latin encoding is specified;
otherwise an iTXt chunk is used and the text is converted from the
specified character set and stored as UTF-8.

JPEG Comment
The encoding for the JPEG Comment (COM segment) is not specified, so
ExifTool reads/writes this text without conversion.

ID3
The ID3v1 specification officially supports only ISO 8859-1 encoding (a
subset of Windows Latin1), although some applications may incorrectly
use other character sets. By default ExifTool converts ID3v1 text from
Latin to the character set specified by the "Charset" option. However,
the internal ID3v1 charset may be specified with the "CharsetID3"
option. The encoding for ID3v2 information is stored in the file, so
ExifTool converts ID3v2 text from this encoding to the character set
specified by the "Charset" option. ExifTool does not currently write ID3
information.

PDF
PDF text strings are stored in either PDFDocEncoding (similar to Windows
Latin1) or Unicode (UCS-2). When reading, ExifTool converts to the
character set specified by the "Charset" option. When writing, ExifTool
encodes input text from the specified character set as Unicode only if
the string contains special characters, otherwise PDFDocEncoding is
used.

Photoshop
Some Photoshop resource names are stored as Pascal strings with unknown
encoding. By default, ExifTool assumes MacRoman encoding and converts
this to UTF-8, but the internal and external character sets may be
specified with the "CharsetPhotoshop" and "Charset" options
respectively.

QuickTime
QuickTime text strings may be stored in a variety of poorly document
formats. ExifTool does its best to decode these according to the
"Charset" option setting. For some QuickTime strings, ExifTool assumes
a default encoding of MacRoman, but this may be changed with the
"CharsetQuickTime" option.

AIFF
AIFF strings are assumed to be stored in MacRoman, and are converted
according to the "Charset" option when reading.

RIFF
The internal encoding of RIFF strings (eg. in AVI and WAV files) is
assumed to be Latin unless otherwise specified by the RIFF CSET chunk or
the "CharsetRIFF" option.

MIE
MIE strings are stored as either UTF-8 or ISO 8859-1. When reading,
UTF-8 strings are converted according to the "Charset" option, and ISO
8859-1 strings are never converted. When writing, input strings are
converted from the specified character set to UTF-8. The resulting
strings are stored as UTF-8 if they contain multi-byte UTF-8 character
sequences, otherwise they are stored as ISO 8859-1.

Vorbis
Vorbis comments are stored as UTF-8, and are converted to the character
set specified by the "Charset" option.

This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

ACKNOWLEDGEMENTS
Many people have helped in the development of ExifTool through their bug
reports, comments and suggestions, and/or additions to the code. See
the ACKNOWLEDGEMENTS in the individual Image::ExifTool modules and in
html/index.html of the Image::ExifTool distribution package for a list
of people who have contributed to this project.

SEE ALSO
exiftool(1), Image::ExifTool::TagNames(3pm),
Image::ExifTool::Shortcuts(3pm), Image::ExifTool::Shift(3pm),
Image::Info(3pm), Image::MetaData::JPEG(3pm)

perl v5.40.1 2025-03-16 Image::ExifTool(3pm)

Generated by dwww version 1.16 on Tue Dec 16 05:14:35 CET 2025.