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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, FLIR, FujiFilm, GE, 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     | EIP   r     | LA    r     | ORF   r/w   | RTF   r
         3G2   r/w   | EPS   r/w   | LFP   r     | OTF   r     | RW2   r/w
         3GP   r/w   | EPUB  r     | LNK   r     | PAC   r     | RWL   r/w
         ACR   r     | ERF   r/w   | M2TS  r     | PAGES r     | RWZ   r
         AFM   r     | EXE   r     | M4A/V r/w   | PBM   r/w   | RM    r
         AI    r/w   | EXIF  r/w/c | MEF   r/w   | PCD   r     | SEQ   r
         AIFF  r     | EXR   r     | MIE   r/w/c | PDB   r     | SO    r
         APE   r     | EXV   r/w/c | MIFF  r     | PDF   r/w   | SR2   r/w
         ARW   r/w   | F4A/V r/w   | MKA   r     | PEF   r/w   | SRF   r
         ASF   r     | FFF   r/w   | MKS   r     | PFA   r     | SRW   r/w
         AVI   r     | FLA   r     | MKV   r     | PFB   r     | SVG   r
         AZW   r     | FLAC  r     | MNG   r/w   | PFM   r     | SWF   r
         BMP   r     | FLV   r     | MOBI  r     | PGF   r     | THM   r/w
         BTF   r     | FPF   r     | MODD  r     | PGM   r/w   | TIFF  r/w
         CHM   r     | FPX   r     | MOS   r/w   | PLIST r     | TORRENT r
         COS   r     | GIF   r/w   | MOV   r/w   | PICT  r     | TTC   r
         CR2   r/w   | GZ    r     | MP3   r     | PMP   r     | TTF   r
         CRW   r/w   | HDP   r/w   | MP4   r/w   | PNG   r/w   | VRD   r/w/c
         CS1   r/w   | HDR   r     | MPC   r     | PPM   r/w   | VSD   r
         DCM   r     | HTML  r     | MPG   r     | PPT   r     | WAV   r
         DCP   r/w   | ICC   r/w/c | MPO   r/w   | PPTX  r     | WDP   r/w
         DCR   r     | IDML  r     | MQV   r/w   | PS    r/w   | WEBP  r
         DFONT r     | IIQ   r/w   | MRW   r/w   | PSB   r/w   | WEBM  r
         DIVX  r     | IND   r/w   | MXF   r     | PSD   r/w   | WMA   r
         DJVU  r     | INX   r     | NEF   r/w   | PSP   r     | WMV   r
         DLL   r     | ITC   r     | NRW   r/w   | QTIF  r/w   | WV    r
         DNG   r/w   | J2C   r     | NUMBERS r   | RA    r     | X3F   r/w
         DOC   r     | JNG   r/w   | ODP   r     | RAF   r/w   | XCF   r
         DOCX  r     | JP2   r/w   | ODS   r     | RAM   r     | XLS   r
         DPX   r     | JPEG  r/w   | ODT   r     | RAR   r     | XLSX  r
         DV    r     | K25   r     | OFR   r     | RAW   r/w   | XMP   r/w/c
         DVB   r/w   | KDC   r     | OGG   r     | RIFF  r     | ZIP   r
         DYLIB r     | KEY   r     | OGV   r     | RSRC  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, the
               FileSize, FileModifyDate and FilePermissions 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.)

           HASH ref
               Reference to a hash containing the options settings.  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, which are similar to the tag names
           but may have 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{$_}
";
               }

           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 List option is disabled (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 ----
";
                   }
                   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
", $exifTool->GetDescription($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 strings 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');

       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 0.

           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 strings 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
                 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.

           CharsetEXIF
               Internal encoding to use for stored EXIF "ASCII" string values.
               Unlike other Charset options, CharsetEXIF may also be set to
               undef to pass through all string values without recoding.
               Default is undef.

           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'.

           Compact
               Flag to write compact output.  Default is 0.  The XMP
               specification suggests that the data be padded with blanks to
               allow in-place editing.  With this flag set the 2kB of padding
               is not written.  Note that this only effects embedded XMP since
               padding is never written for stand-alone XMP files.

           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 0.

           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
               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.  The default
               is similar to a format of "%Y:%m:%d %H:%M:%S".  If date can not
               be converted, value is left unchanged unless the StrictDate
               option is set.  Timezones are ignored.

           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".

           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 0.

           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.  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.  Default is 0.

           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.

           GoNoInterpolate
               Disable interpolation for geotagging.  With this flag set to 1,
               geotagging uses the nearest fix instead of interpolating
               between fixes.  Default is 0.

           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.pl), 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 0.

           List
               Flag to extract lists of PrintConv values into arrays instead
               of joining them into a string of values.  The "ListSep" option
               specifies the separator used when combining values.  Default is
               0.

           ListSep
               Separator string used to join lists of PrintConv values when
               "List" option is not set.  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.)  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 (default)
                 1 - Extract and rebuild maker notes into self-contained block
                 2 - Extract without rebuilding maker notes

           MissingTagValue
               Value for missing tags in expressions evaluated by
               "SetNewValuesFromFile".  If not set, a minor error is issued
               for missing values, or the value is set to '' if
               "IgnoreMinorErrors" is set.  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.  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 0.

           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).  Note that this flag is set automatically during
               a call to "SetNewValuesFromFile" to make all tags available for
               copying.  Default is 0.

           ScanForXMP
               Flag for 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 0.

           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.

           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 - 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

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

           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.

           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).

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

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

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

           $exifTool->ClearOptions();

       Inputs:
           0) ExifTool object reference

       Return Values:
           (none)

   ExtractInfo
       Extract all meta information from an image.

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

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

           Binary, Charset, CharsetEXIF, CharsetID3, CharsetIPTC,
           CharsetPhotoshop, CharsetQuickTime, Composite, ExtractEmbedded,
           FastScan, FixBase, HtmlDump, HtmlDumpBase, IgnoreMinorErrors, Lang,
           LargeFileSupport, MakerNotes, PNGEarlyXMP, ScanForXMP, Struct,
           TextOut, Unknown and Verbose.

       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,
           Group#, GlobalTimeShift, Lang, List, ListSep, PrintConv, Sort (if a
           tag list reference is given) and StrictDate.

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

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

           # 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, 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, CharsetIPTC, Compact, Compress,
       FixBase, IgnoreMinorErrors, 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, or the original raw (Raw) value.  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 List 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)
";
           } else {
               print "$tag = $val
";
           }

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

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

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

       Charset, CoordFormat, DateFormat, Escape, GlobalTimeShift, Lang, List,
       ListSep, PrintConv and StrictDate.

       Inputs:
           0) ExifTool object reference

           1) Tag key

           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
           values and the List option is disabled 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.
           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);

           # 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.php#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.
               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.  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.pl 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 as in
           the last example above 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, Escape, IgnoreMinorErrors, Lang, ListSep, ListSplit,
       PrintConv, Verbose and WriteMode.

   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, 'IPTC:Keywords>XMP-dc:Subject');

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

           # 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 an
           expression 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 Perl expressions placed inside the braces and after a
           semicolon following the tag name.  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.

   GetNewValues
       Get list of new Raw values for the specified tag.  These are the values
       that will be written to file.  Most tags return only a single value,
       but List-type tags may return multiple values.

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

           @rawVals = $exifTool->GetNewValues($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).

   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, and requires Win32API::File::Time to be
           installed.

   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, so 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.  However if you enable the
           Composite option, "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, CanonVRD, Composite, DICOM, DNG, DV,
           DjVu, Ducky, EXE, EXIF, ExifTool, FLAC, FLIR, File, Flash,
           FlashPix, Font, FotoStation, GIF, GIMP, GeoTiff, H264, HTML,
           ICC_Profile, ID3, IPTC, ITC, JFIF, JPEG, Jpeg2000, LNK, Leaf,
           Lytro, M2TS, MIE, MIFF, MNG, MPC, MPEG, MPF, MXF, MakerNotes,
           Matroska, Meta, Ogg, OpenEXR, PDF, PICT, PLIST, PNG, PSP, Palm,
           PanasonicRaw, PhotoCD, PhotoMechanic, Photoshop, PostScript,
           PrintIM, QuickTime, RAF, RIFF, RSRC, RTF, Radiance, Rawzor, Real,
           SVG, SigmaRaw, Stim, Theora, Torrent, Vorbis, XML, XMP, ZIP

       Family 1 (Specific Location):
           AC3, AFCP, AIFF, APE, ASF, AVI1, Adobe, AdobeCM, AdobeDNG, Apple,
           CIFF, Canon, CanonCustom, CanonRaw, CanonVRD, Casio, Chapter#,
           Composite, DICOM, 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, 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#, ITC, InteropIFD, JFIF, JPEG, JPEG-HDR,
           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, MPC, MPEG, MPF0,
           MPImage, MXF, MakerNotes, MakerUnknown, Matroska, MediaJukebox,
           MetaIFD, Microsoft, Minolta, MinoltaRaw, NITF, Nikon, NikonCapture,
           NikonCustom, NikonScan, Nintendo, Ocad, Ogg, Olympus, OpenEXR, 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, Ricoh, SPIFF, SR2, SR2DataIFD, SR2SubIFD, SRF#, SVG,
           Samsung, Sanyo, Scalado, Sigma, SigmaRaw, Sony, SonyIDC, Stim,
           SubIFD, System, Theora, Torrent, Track#, Version0, Vorbis, XML,
           XMP, XMP-DICOM, XMP-GPano, XMP-MP, XMP-MP1, XMP-PixelLive, XMP-aas,
           XMP-acdsee, XMP-album, XMP-apple-fi, XMP-aux, XMP-cc, XMP-cell,
           XMP-crs, XMP-dc, XMP-dex, XMP-digiKam, 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-prism, XMP-prl, 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,
           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, CIFF, CanonVRD,
           Ducky, EXIF, ExifIFD, File, FlashPix, FotoStation, GPS,
           GlobParamIFD, ICC_Profile, IFD0, IFD1, IPTC, InteropIFD, JFIF,
           Jpeg2000, MIE, MPF, MakerNotes, Meta, MetaIFD, NikonCapture, PDF,
           PDF-update, PNG, PhotoMechanic, Photoshop, PrintIM, RMETA, RSRC,
           SubIFD, Trailer, XML, XML-*, XMP, XMP-*

           All names in this list are either family 0 or family 1 group names,
           with the exception of 'Trailer' which allows all trailers in JPEG
           and TIFF-format images to be deleted at once, including unknown
           trailers.  To schedule a group for deletion, call "SetNewValue"
           with an undefined value and a tag name like 'Trailer:*'.

           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.  Set
           to 0 to return type for recognized but unsupported files (otherwise
           the return value for unsupported files is undef).

       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 array
           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, 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
       the 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.

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 Set:
           The encoding for strings passed to/from ExifTool API functions.
           This is set via the "Charset" option, which is 'UTF8' by default.

       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" and "CharsetQuickTime" 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.

   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 "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.

   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 2003-2014, 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.php 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.pl,
       Image::Info(3pm), Image::MetaData::JPEG(3pm)



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