Provided by: libimage-exiftool-perl_11.16-1_all bug

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 = new Image::ExifTool;

         # 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):

         File Types
         ------------+-------------+-------------+-------------+------------
         3FR   r     | DR4   r/w/c | J2C   r     | ODP   r     | RAW   r/w
         3G2   r/w   | DSS   r     | JNG   r/w   | ODS   r     | RIFF  r
         3GP   r/w   | DV    r     | JP2   r/w   | ODT   r     | RSRC  r
         A     r     | DVB   r/w   | JPEG  r/w   | OFR   r     | RTF   r
         AA    r     | DVR-MS r    | JSON  r     | OGG   r     | RW2   r/w
         AAE   r     | DYLIB r     | K25   r     | OGV   r     | RWL   r/w
         AAX   r/w   | EIP   r     | KDC   r     | OPUS  r     | RWZ   r
         ACR   r     | EPS   r/w   | KEY   r     | ORF   r/w   | RM    r
         AFM   r     | EPUB  r     | LA    r     | OTF   r     | SEQ   r
         AI    r/w   | ERF   r/w   | LFP   r     | PAC   r     | SKETCH r
         AIFF  r     | EXE   r     | LNK   r     | PAGES r     | SO    r
         APE   r     | EXIF  r/w/c | M2TS  r     | PBM   r/w   | SR2   r/w
         ARQ   r/w   | EXR   r     | M4A/V r/w   | PCD   r     | SRF   r
         ARW   r/w   | EXV   r/w/c | MAX   r     | PDB   r     | SRW   r/w
         ASF   r     | F4A/V r/w   | MEF   r/w   | PDF   r/w   | SVG   r
         AVI   r     | FFF   r/w   | MIE   r/w/c | PEF   r/w   | SWF   r
         AZW   r     | FLA   r     | MIFF  r     | PFA   r     | THM   r/w
         BMP   r     | FLAC  r     | MKA   r     | PFB   r     | TIFF  r/w
         BPG   r     | FLIF  r/w   | MKS   r     | PFM   r     | TORRENT r
         BTF   r     | FLV   r     | MKV   r     | PGF   r     | TTC   r
         CHM   r     | FPF   r     | MNG   r/w   | PGM   r/w   | TTF   r
         COS   r     | FPX   r     | MOBI  r     | PLIST r     | VCF   r
         CR2   r/w   | GIF   r/w   | MODD  r     | PICT  r     | VRD   r/w/c
         CR3   r/w   | GPR   r/w   | MOI   r     | PMP   r     | VSD   r
         CRM   r/w   | GZ    r     | MOS   r/w   | PNG   r/w   | WAV   r
         CRW   r/w   | HDP   r/w   | MOV   r/w   | PPM   r/w   | WDP   r/w
         CS1   r/w   | HDR   r     | MP3   r     | PPT   r     | WEBP  r
         DCM   r     | HEIC  r     | MP4   r/w   | PPTX  r     | WEBM  r
         DCP   r/w   | HEIF  r     | MPC   r     | PS    r/w   | WMA   r
         DCR   r     | HTML  r     | MPG   r     | PSB   r/w   | WMV   r
         DFONT r     | ICC   r/w/c | MPO   r/w   | PSD   r/w   | WTV   r
         DIVX  r     | ICS   r     | MQV   r/w   | PSP   r     | WV    r
         DJVU  r     | IDML  r     | MRW   r/w   | QTIF  r/w   | X3F   r/w
         DLL   r     | IIQ   r/w   | MXF   r     | R3D   r     | XCF   r
         DNG   r/w   | IND   r/w   | NEF   r/w   | RA    r     | XLS   r
         DOC   r     | INX   r     | NRW   r/w   | RAF   r/w   | XLSX  r
         DOCX  r     | ISO   r     | NUMBERS r   | RAM   r     | XMP   r/w/c
         DPX   r     | ITC   r     | O     r     | RAR   r     | ZIP   r

         Meta Information
         ----------------------+----------------------+---------------------
         EXIF           r/w/c  |  CIFF           r/w  |  Ricoh RMETA    r
         GPS            r/w/c  |  AFCP           r/w  |  Picture Info   r
         IPTC           r/w/c  |  Kodak Meta     r/w  |  Adobe APP14    r
         XMP            r/w/c  |  FotoStation    r/w  |  MPF            r
         MakerNotes     r/w/c  |  PhotoMechanic  r/w  |  Stim           r
         Photoshop IRB  r/w/c  |  JPEG 2000      r    |  DPX            r
         ICC Profile    r/w/c  |  DICOM          r    |  APE            r
         MIE            r/w/c  |  Flash          r    |  Vorbis         r
         JFIF           r/w/c  |  FlashPix       r    |  SPIFF          r
         Ducky APP12    r/w/c  |  QuickTime      r    |  DjVu           r
         PDF            r/w/c  |  Matroska       r    |  M2TS           r
         PNG            r/w/c  |  MXF            r    |  PE/COFF        r
         Canon VRD      r/w/c  |  PrintIM        r    |  AVCHD          r
         Nikon Capture  r/w/c  |  FLAC           r    |  ZIP            r
         GeoTIFF        r/w/c  |  ID3            r    |  (and more)

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 = new Image::ExifTool;

       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.

           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.  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 = new Image::ExifTool;
               $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.

       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.

           # 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:
           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.

           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.

           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
                 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.  When set
               in Windows, this triggers use of Windows wide-character i/o library routines
               (requires Win32API::File).  Default is undef.  May also be set to an empty string
               to avoid "encoding not 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
               Option to write compact XMP output.  The XMP specification suggests that the data
               be padded with blanks to allow in-place editing. With this flag set to 1, the 2 kB
               of padding is not written.  Note that this only effects embedded XMP since padding
               is never written for stand-alone XMP files.  When set to 2, spaces to indent XMP
               for readability are also dropped.  Default is undef.  Also see the XMPShorthand
               option for reducing the size of XMP.

           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
               Compress::Zlib is installed.  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 "+" to the first
               format specifier (eg. "%+.6f") prints a signed coordinate instead.  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 for
               details about the format string.  If date can not be converted, value is left
               unchanged unless the StrictDate option is set.  Timezones are ignored.  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.

           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 from tags extracted from an image.  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, streaming metadata in AVCHD videos, and the resource fork of Mac OS
               files.  Default is undef.

           FastScan
               Flag to increase speed of extracting information from JPEG images.  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 with 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.  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.  When set to 3, the file is not actually parsed, and
               only an initial guess at FileType and some pseudo tags are returned.  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 value is not changed if $_ is set to undef.  Applies to all
               returned values unless PrintConv option is disabled.

           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.

           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, the coordinates of the nearest fix are taken.  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.  Default is
               undef.

           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.

           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.

           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.

           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.  Default
               is undef.

           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.  If not set, a minor error is
               issued for missing values, or the value is set to '' if "IgnoreMinorErrors" is
               set.  Default is undef.

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

           PNGEarlyXMP
               Flag to write XMP in PNG images before the IDAT (image data) chunk.  By default,
               ExifTool adds new XMP to the end of a PNG file (just before IEND).  This is
               allowed by the PNG and XMP specifications, but some utilities seem to ignore XMP
               if it comes after the image data.  The PNGEarlyXMP option causes ExifTool to
               instead add new XMP before the PNG IDAT chunk.  However, since ExifTool uses a
               single-pass writing algorithm, it has no way to tell if XMP already exists later
               in the file before writing the new XMP in this location.  If this happens, a minor
               error is issued when the extra XMP is encountered, and the file is not written.
               Adding the "IgnoreMinorErrors" option causes the XMP after IDAT to be deleted,
               thus resolving the conflict (at the expense of possible metadata loss), and
               allowing the file to be written.  The PNGEarlyXMP option is applied automatically
               when deleting all XMP and writing new XMP back in one step.  When reading, this
               option causes a warning to be issued if standard XMP is found after the IDAT
               chunk.

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

           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.  This option also
               disables the autodetection 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.

           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.  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

           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
               Time zone for local date/time values.  May be set to any valid TZ string.  Uses
               the system time zone if not specified.  Default is undef.  (Requires POSIX::tzset,
               which may not be available in Windows.  A work-around in Windows is to "set
               TZ=<zone>" before running ExifTool.)

           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')".  If called without no additional arguments,
               "Options('UserParam')" returns a reference to the hash of all user parameters
               (with lower-case names).

           Validate
               Flag to perform extra validation 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.

           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).

           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.

           XMPShorthand
               Flag set to write xmp in shorthand format.  Default is undef.

       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.  The following
           options are effective in the call to "ExtractInfo":

           Binary, Charset, CharsetEXIF, CharsetFileName, CharsetID3, CharsetIPTC,
           CharsetPhotoshop, CharsetQuickTime, CharsetRIFF, Composite, ExtendedXMP,
           ExtractEmbedded, FastScan, FixBase, HtmlDump, HtmlDumpBase, IgnoreMinorErrors, Lang,
           LargeFileSupport, MakerNotes, MDItemTags, NoPDFList, Password, PNGEarlyXMP,
           QuickTimeUTC (enforced 1904 time zero), RequestAll, RequestTags, ScanForXMP, Struct,
           TextOut, Unknown, Verbose, XAttrTags and XMPAutoConv.

       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.  Options in effect are:

           Charset, CoordFormat, DateFormat, Duplicates, Escape, Exclude, Filter, Group#,
           GlobalTimeShift, Lang, ListItem, ListJoin, PrintConv, Sort (if a tag list reference is
           given) and StrictDate.

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

       The following options are effective in the call to "GetInfo":

       Charset, CoordFormat, DateFormat, Duplicates, Escape, Exclude, Filter, Group#,
       GlobalTimeShift, Lang, ListItem, ListJoin, PrintConv, QuickTimeUTC (conversion to local
       time), Sort (if a tag list reference is given) and StrictDate.

   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.

       Note that 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, 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.

       The following ExifTool options are effective in the call to "WriteInfo":

       ByteOrder, Charset, CharsetEXIF, CharsetFileName, CharsetIPTC, Compact, Compress, FixBase,
       IgnoreMinorErrors, Password, PNGEarlyXMP and Verbose.

   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');

       The following options are in effect when "GetValue" is called:

       Charset, CoordFormat, DateFormat, Escape, Filter, GlobalTimeShift, Lang, ListItem,
       ListJoin, PrintConv, QuickTimeUTC (conversion to local time), and StrictDate.

       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' 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.  '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.

       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 <http://owl.phy.queensu.ca/~phil/exiftool/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 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.  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 previous new values
               for this tag and replace with the specified new value) or 2 (reset previous new
               values only).

           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').

       The following ExifTool options are effective in the call to "SetNewValue":

       Charset, DateFormat, Escape, IgnoreMinorErrors, Lang, ListJoin, ListSplit, PrintConv,
       QuickTimeUTC, StrictDate, Verbose and WriteMode.

   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);

       Inputs:
           0) ExifTool object reference

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

       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 or 2 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).  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 the
           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.  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".

           - 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.

   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 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] 'Link' to create a hard 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 if the file name or directory was changed, 0 if nothing was done, or -1 if there was
           an error renaming the file.

       Notes:
           Will not overwrite existing files. New directories are created as necessary.

   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 then XMP.
       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...)

           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.)

           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 have family 4 group names of 'Copy1', 'Copy2',
           'Copy3', etc.

           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.

   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 (0-4)

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

       Family 1 (Specific Location):
           AC3, AFCP, AIFF, APE, ASF, AVI1, Adobe, AdobeCM, AdobeDNG, Apple, Audible, CIFF,
           CameraIFD, Canon, CanonCustom, CanonRaw, CanonVRD, Casio, Chapter#, Composite, DICOM,
           DJI, DNG, DV, DjVu, DjVu-Meta, Ducky, EPPIM, EXE, EXIF, ExifIFD, ExifTool, FLAC, FLIR,
           File, Flash, FlashPix, Font, FotoStation, FujiFilm, FujiIFD, GE, GIF, GIMP, GPS,
           GeoTiff, GlobParamIFD, GoPro, GraphConv, H264, HP, HTC, HTML, HTML-dc, HTML-ncc, HTML-
           office, HTML-prod, HTML-vw96, HTTP-equiv, ICC-chrm, 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, IPTC, IPTC#, ISO, ITC, InteropIFD, JFIF, JFXX, JPEG,
           JPEG-HDR, JSON, JVC, Jpeg2000, KDC_IFD, Kodak, KodakBordersIFD, KodakEffectsIFD,
           KodakIFD, KyoceraRaw, LNK, Leaf, LeafSubIFD, Leica, Lytro, M2TS, MAC, MIE-Audio, MIE-
           Camera, MIE-Canon, MIE-Doc, MIE-Extender, MIE-Flash, MIE-GPS, MIE-Geo, MIE-Image, MIE-
           Lens, MIE-Main, MIE-MakerNotes, MIE-Meta, MIE-Orient, MIE-Preview, MIE-Thumbnail, MIE-
           UTM, MIE-Unknown, MIE-Video, MIFF, MNG, MOBI, MOI, MPC, MPEG, MPF0, MPImage, MS-DOC,
           MXF, MacOS, MakerNotes, MakerUnknown, Matroska, MediaJukebox, MetaIFD, Microsoft,
           Minolta, MinoltaRaw, Motorola, NITF, Nikon, NikonCapture, NikonCustom, NikonScan,
           Nintendo, Ocad, Ogg, Olympus, OpenEXR, Opus, PDF, PICT, PNG, PNG-pHYs, PSP, Palm,
           Panasonic, PanasonicRaw, Pentax, PhaseOne, PhotoCD, PhotoMechanic, Photoshop,
           PictureInfo, PostScript, PreviewIFD, PrintIM, ProfileIFD, Qualcomm, QuickTime, RAF,
           RAF2, RIFF, RMETA, RSRC, RTF, Radiance, Rawzor, Real, Real-CONT, Real-MDPR, Real-PROP,
           Real-RA3, Real-RA4, Real-RA5, Real-RJMD, Reconyx, Red, Ricoh, SPIFF, SR2, SR2DataIFD,
           SR2SubIFD, SRF#, SVG, Samsung, Sanyo, Scalado, Sigma, SigmaRaw, Sony, SonyIDC, Stim,
           SubIFD, System, Theora, Torrent, Track#, VCalendar, VCard, Version0, Vorbis, WTV, XML,
           XMP, XMP-DICOM, XMP-GAudio, XMP-GImage, XMP-GPano, XMP-GSpherical, XMP-MP, XMP-MP1,
           XMP-PixelLive, XMP-aas, XMP-acdsee, XMP-album, XMP-apple-fi, XMP-aux, XMP-cc, XMP-
           cell, XMP-creatorAtom, XMP-crs, XMP-dc, XMP-dex, XMP-digiKam, XMP-drone-dji, XMP-dwc,
           XMP-exif, XMP-exifEX, XMP-expressionmedia, XMP-extensis, XMP-fpv, XMP-getty, XMP-ics,
           XMP-iptcCore, XMP-iptcExt, XMP-lr, XMP-mediapro, XMP-microsoft, XMP-mwg-coll, XMP-mwg-
           kw, XMP-mwg-rs, XMP-pdf, XMP-pdfx, XMP-photomech, XMP-photoshop, XMP-plus, XMP-pmi,
           XMP-prism, XMP-prl, XMP-prm, XMP-pur, XMP-rdf, XMP-swf, XMP-tiff, XMP-x, XMP-xmp, XMP-
           xmpBJ, XMP-xmpDM, XMP-xmpMM, XMP-xmpNote, XMP-xmpPLUS, XMP-xmpRights, XMP-xmpTPg, ZIP

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

       Family 3 (Document Number):
           Doc#, Main

       Family 4 (Instance Number):
           Copy#

   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:

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

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.

       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 a 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.

AUTHOR

       Copyright 2003-2018, Phil Harvey

       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)