Image::ExifTool(3)

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
ExifTool provides an extensible set of perl modules to read and write meta information in a wide variety of files, including the maker note information of many digital cameras by various manufacturers such as Canon, Casio, FujiFilm, HP, JVC/Victor, Kodak, Leaf, Minolta/Konica-Minolta, Nikon, Olympus/Epson, Panasonic/Leica, Pentax/Asahi, 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     | DVB   r     | M2TS  r     | PAGES r     | RW2   r/w
  3G2   r     | DYLIB r     | M4A/V r     | PBM   r/w   | RWL   r/w
  3GP   r     | EIP   r     | MEF   r/w   | PDF   r/w   | RWZ   r
  ACR   r     | EPS   r/w   | MIE   r/w/c | PEF   r/w   | RM    r
  AFM   r     | ERF   r/w   | MIFF  r     | PFA   r     | SO    r
  AI    r/w   | EXE   r     | MKA   r     | PFB   r     | SR2   r/w
  AIFF  r     | EXIF  r/w/c | MKS   r     | PFM   r     | SRF   r
  APE   r     | F4A/V r     | MKV   r     | PGM   r/w   | SRW   r/w
  ARW   r/w   | FLA   r     | MNG   r/w   | PICT  r     | SVG   r
  ASF   r     | FLAC  r     | MOS   r/w   | PMP   r     | SWF   r
  AVI   r     | FLV   r     | MOV   r     | PNG   r/w   | THM   r/w
  BMP   r     | FPX   r     | MP3   r     | PPM   r/w   | TIFF  r/w
  BTF   r     | GIF   r/w   | MP4   r     | PPT   r     | TTC   r
  COS   r     | GZ    r     | MPC   r     | PPTX  r     | TTF   r
  CR2   r/w   | HDP   r/w   | MPG   r     | PS    r/w   | VRD   r/w/c
  CRW   r/w   | HTML  r     | MPO   r/w   | PSB   r/w   | WAV   r
  CS1   r/w   | ICC   r/w/c | MQV   r     | PSD   r/w   | WDP   r/w
  DCM   r     | IIQ   r     | MRW   r/w   | PSP   r     | WEBP  r
  DCP   r/w   | IND   r/w   | NEF   r/w   | QTIF  r     | WEBM  r
  DCR   r     | ITC   r     | NRW   r/w   | RA    r     | WMA   r
  DFONT r     | JNG   r/w   | NUMBERS r   | RAF   r/w   | WMV   r
  DIVX  r     | JP2   r/w   | ODP   r     | RAM   r     | X3F   r/w
  DJVU  r     | JPEG  r/w   | ODS   r     | RAR   r     | XCF   r
  DLL   r     | K25   r     | ODT   r     | RAW   r/w   | XLS   r
  DNG   r/w   | KDC   r     | OGG   r     | RIFF  r     | XLSX  r
  DOC   r     | KEY   r     | ORF   r/w   | RSRC  r     | XMP   r/w/c
  DOCX  r     | LNK   r     | OTF   r     | RTF   r     | ZIP   r

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

or the configuration feature may 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 returns an error string when called in list context, or sends the error to STDERR otherwise). 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.

  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(). ie)

    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. The advantage of using the object-oriented form is that the 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 (ie. '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 (ie. '*:WhiteBalance'). Multiple groups may be specified (ie. 'EXIF:Time:*' extracts all EXIF Time tags). And finally, a leading '-' indicates a tag to be excluded (ie. '-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 tag array 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 (ie. 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 all extracted tags.

    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 embedded instance number if multiple tags with the same name were extracted from the image. Many of the ExifTool functions require a tag key as an argument. Use "GetTagName [static]" to get the tag name for a given tag key. Note that the case of the tag names may not be the same as requested. Here is a simple example to print out the information returned by "ImageInfo":

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

    Values of the returned hash are usually simple scalars, but a scalar reference is used to indicate binary data and an array reference may be used to indicate a list. 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 set. If not extracted the value is a reference to a string of the form "Binary data ##### bytes". The value may also be a hash reference if the Struct option is enabled.

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

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

Notes:
    ExifTool returns all values as byte strings of encoded characters. Perl wide characters are not used. See "CHARACTER ENCODINGS" for details about the encodings.

    As well as tags representing information extracted from the image, the following 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.

The initial default options are obtained from values in the %Image::ExifTool::UserDefined::Options hash if it exists. See the .ExifTool_config file in the full ExifTool distribution for details.

    # 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.

    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 (ie. 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.

    CharsetID3
        Character 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 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
        Character encoding to assume for Photoshop IRB resource names. Default is Latin.

    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. By setting this flag, 2kB is saved for files with XMP data.

    Composite
        Flag to calculate Composite tags automatically. 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. 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 preceeding their name with a '-' in the arguments to "ImageInfo".

    ExtractEmbedded
        Flag to extract information from embedded documents in PostScript files and the AIPrivateData stream in PDF files, and embedded MPF images in JPEG and MPO 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 (ie. 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 fails if the Geotime value lies between two fixes in the same track which are separated by a number of seconds greater than this. 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. 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.

    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
        Specifies 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/warnings are denoted by '[minor]' at the start of the message.

    Lang
        Localized language for exiftool tag descriptions, etc. Available languages are given by the Image::ExifTool::Lang module names (ie. 'fr'). 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. (ie. 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 processing 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.

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

    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:

          Alpha  - Sort alphabetically
          File   - Sort in order that tags were found in the file
          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.
          Input  - Sort in same order as input tag arguments (default)

    StrictDate
        Flag to return undefined value for any date which can't be converted when the DateFormat option is used. Default is 0.

    Struct
        Flag to return XMP structures as hash references instead of flattening into individual tags. Default is 0. Currently, the struct feature applies only when reading (so "SetNewValue" can not be called with a hash reference when writing).

    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.

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, CharsetID3, CharsetIPTC, Composite, ExtractEmbedded, FastScan, FixBase, HtmlDump, HtmlDumpBase, IgnoreMinorErrors, Lang, LargeFileSupport, MakerNotes, 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 hieght only
    $info = $exifTool->GetInfo('ImageWidth', 'ImageHeight');

    # 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#, Lang, List, ListSep, StrictDate, 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

    2) [optional] Destination file name, file reference, scalar reference, or undef to overwrite the original file

    3) [optional] Destination file type

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 this routine 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 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 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. 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.

    The destination file type is only used if the source file is undefined.

    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, CharsetID3, CharsetIPTC, Compact, Compress, FixBase, IgnoreMinorErrors and Verbose.

  CombineInfo
Combine information from more than one information hash into a single hash.

    $info = $exifTool->CombineInfo($info1, $info2, $info3);

Inputs:
    0) ExifTool object reference

    1-N) Information hash references

If the Duplicates option is disabled and duplicate tags exist, the order of the hashes is significant. In this case, the value used is the first value found as the hashes are scanned in order of input. The Duplicates option is the only option that is in effect for this function.

  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 ('File', 'Input', 'Alpha' or 'Group#').

    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 ('File', 'Input', 'Alpha' or 'Group#')

    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)\n";
    } else {
        print "$tag = $val\n";
    }

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

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

Inputs:
    0) ExifTool object reference

    1) Tag key

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

    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.

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.

  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 1 hour
    $exifTool->SetNewValue(DateTimeOriginal => '1:00', 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

Inputs:
    0) ExifTool object reference

    1) [optional] Tag key or tag name, or undef to clear all new values. A tag name of '*' can be used when deleting tags to delete all tags, or all tags in a specified group. The tag name may be prefixed by group name, separated by a colon (ie. 'EXIF:Artist'), which is equivalent to using a Group option argument. Also, a '#' may be appended to the tag name (ie. 'EXIF:Orientation#'), with the same effect as setting Type to 'ValueConv'.

    2) [optional] New value for tag. Undefined to delete tag from file. May be a scalar, scalar reference, or list reference to set a list of values. Integer values may be specified in hexadecimal (with a leading '0x'), and simple rational values may be specified as fractions.

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

SetNewValue Options:
    AddValue
        Specifies that the value be added to an existing list rather than replacing the list. Valid values are 0 or 1. Default is 0.

    DelValue
        Delete the existing tag if it has the specified value. Valid 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. Default is 0.

    EditOnly
        Edit tag only if it already exists. Don't create new tag. Valid values are 0 and 1. 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". Any family 0 or 1 group name may be used. Case is not significant.

    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.

    Replace
        Flag to replace the previous new value for this tag (ie. replace the value set in a previous call to "SetNewValue"). Valid values are 0 (don't replace), 1 (replace with specified new value) or 2 (reset previous new value only).

    Shift
        Shift the tag by the specified value. Currently only date/time tags can be shifted. Undefined for no shift, 1 for a positive shift, or -1 for a negative shift. If 0, the shift is applied only if the tag is shiftable, and the shift is positive if AddValue is set, or negative 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.

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. Instead, use "SetNewValuesFromFile" to recover the values of individual tags after deleting a group.

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

Charset, Escape, IgnoreMinorErrors, Lang, ListSep, ListSplit, PrintConv and Verbose.

  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:*>*:*');

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 an optional family 0 or 1 group name, separated by a colon (ie. 'exif:iso'). A leading '-' indicates tags to be excluded (ie. '-comment'), or a trailing '#' causes the ValueConv value to be copied (same as setting the Type option to 'ValueConv' for this tag only). An asterisk ('*') may be used for the tag name, and is useful when a group is specified to set all tags from a group (ie. 'XMP:*'). A special feature allows tag names of the form 'SRCTAG>DSTTAG' (or 'DSTTAG<SRCTAG') to be specified to copy information to a tag with a different name or a specified group. Both 'SRCTAG' and 'DSTTAG' may use '*' and/or be prefixed by a group name (ie. 'modifyDate>fileModifyDate' or '*>xmp:*'). Copied tags may also be added or deleted from a list with arguments of the form 'SRCTAG+>DSTTAG' or 'SRCTAG->DSTTAG'. 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 (ie. '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.) 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, the family 1 group of the original tag is preserved. (For example, specifying '*:*' copies all information while preserving the original family 1 groups.)

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.

  GetNewValues
Get list of new Raw values for the specified tag. These are the values that will be written to file. Only tags which support a 'List' may return more than one value.

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

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

Inputs:
    0) ExifTool object reference

    1) Tag name (case sensitive, group names not allowed)

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:
    None.

  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
Set the file modification time from the new value of the FileModifyDate 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)

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 tag has been set. If a timezone is not specified in the FileModifyDate value, local time is assumed. When shifting FileModifyDate, the time of the original file is used unless an optional base time is specified.

  SetFileName
Set the file name and directory. If not specified, the new file name is derived from the new values of the FileName and Directory tags. 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

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 (ie. 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 (ie. 'EXIF');
    $group = $exifTool->GetGroup($tag, 0);

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

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

    # return groups as a simplified string (ie. '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             (ie. EXIF, XMP, IPTC)
        1) Specific Location            (ie. IFD0, XMP-dc)
        2) Category                     (ie. Author, Time)
        3) Document Number              (ie. Main, Doc1, Doc3-2)
        4) Instance Number              (ie. Copy1, Copy2, Copy3...)

    Families 0 and 1 are based on the file structure, and are similar except that family 1 is more specific -- it sub-divides the EXIF, MakerNotes, XMP and ICC_Profile groups to give more detail about the specific location where the information was found. 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 when the "ExtractEmbedded" option is used. Nested sub-documents (if they exist) are indicated by numbers separated with dashes in the group name, to an arbitrary depth. (ie. '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, APP12, APP13, APP14, APP15, APP4, APP5, APP6, APP8, ASF, BMP, CanonVRD, Composite, DICOM, DNG, DjVu, Ducky, EXE, EXIF, ExifTool, FLAC, File, Flash, FlashPix, Font, FotoStation, GIF, GIMP, GeoTiff, H264, HTML, ICC_Profile, ID3, IPTC, ITC, JFIF, JPEG, Jpeg2000, LNK, Leaf, M2TS, MIE, MIFF, MNG, MPC, MPEG, MPF, MakerNotes, Matroska, Meta, PDF, PICT, PNG, PSP, PhotoMechanic, Photoshop, PostScript, PrintIM, QuickTime, RAF, RIFF, RSRC, RTF, Rawzor, Real, SVG, SigmaRaw, Stim, Vorbis, XML, XMP, ZIP

Family 1 (Specific Location):
    AC3, AFCP, AIFF, APE, ASF, AVI1, Adobe, AdobeCM, BMP, CIFF, Canon, CanonCustom, CanonRaw, CanonVRD, Casio, Chapter#, Composite, DICOM, DNG, DjVu, DjVu-Meta, Ducky, EPPIM, EXE, EXIF, ExifIFD, ExifTool, FLAC, File, Flash, FlashPix, Font, FotoStation, FujiFilm, GIF, GIMP, GPS, GeoTiff, GlobParamIFD, GraphConv, H264, HP, 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, JVC, Jpeg2000, KDC_IFD, Kodak, KodakBordersIFD, KodakEffectsIFD, KodakIFD, KyoceraRaw, LNK, Leaf, LeafSubIFD, Leica, 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, MPC, MPEG, MPF0, MPImage, MakerNotes, MakerUnknown, Matroska, MetaIFD, Microsoft, Minolta, MinoltaRaw, NITF, Nikon, NikonCapture, NikonCustom, NikonScan, Olympus, PDF, PICT, PNG, PSP, Panasonic, Pentax, PhotoMechanic, Photoshop, PictureInfo, PostScript, PreviewIFD, PrintIM, ProfileIFD, QuickTime, RAF, RAF2, RIFF, RMETA, RSRC, RTF, Rawzor, Real, Real-CONT, Real-MDPR, Real-PROP, Real-RA3, Real-RA4, Real-RA5, Real-RJMD, Ricoh, SPIFF, SR2, SR2DataIFD, SR2SubIFD, SRF#, SVG, Samsung, Sanyo, Scalado, Sigma, SigmaRaw, Sony, SonyIDC, Stim, SubIFD, System, Track#, Version0, Vorbis, XML, XMP, XMP-DICOM, XMP-MP, XMP-MP1, XMP-PixelLive, XMP-acdsee, XMP-album, XMP-aux, XMP-cc, XMP-crs, XMP-dc, XMP-dex, XMP-digiKam, XMP-exif, XMP-iptcCore, XMP-iptcExt, XMP-lr, XMP-mediapro, XMP-microsoft, 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, CIFF, CanonVRD, EXIF, ExifIFD, Ducky, File, FlashPix, FotoStation, GlobParamIFD, GPS, IFD0, IFD1, InteropIFD, ICC_Profile, IPTC, JFIF, MakerNotes, Meta, MetaIFD, MIE, PhotoMechanic, Photoshop, PNG, PrintIM, RMETA, SubIFD, Trailer, 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:*'.

  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

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 recognized file types if no input extension is specified. 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 and EXIF files.

CHARACTER ENCODINGS
Certain meta information formats allow coded character sets other than plain ASCII. When reading, 8-bit encodings are passed straight through ExifTool without re-coding unless specified otherwise below, and multi-byte encodings are converted according to the "Charset" option ('UTF8' by default). When writing, the inverse conversions are performed. See the "Charset" option for a list of valid character sets.

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

  EXIF
Most textual information in EXIF is stored in ASCII format, and ExifTool does not convert these tags. However it is not uncommon for applications to write UTF-8 or other encodings where ASCII is expected, and ExifTool will quite happily read/write any encoding without conversion. For a few EXIF tags (UserComment, GPSProcessingMethod and GPSAreaInformation) the stored text may be encoded either in ASCII, Unicode (UCS-2) or JIS. When reading these tags, Unicode and JIS are converted to the character set specified by the "Charset" option. Other encodings are not converted. When writing, text is stored as ASCII unless the string contains special characters, in which case it is converted from the specified character set and stored as Unicode. ExifTool writes Unicode in native EXIF byte ordering by default, but this may be changed by setting the ExifUnicodeByteOrder tag. The EXIF "XP" tags (XPTitle, XPComment, etc) are always stored as little-endian Unicode, 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 found. See <http://www.iptc.org/IIM/> for the official IPTC specification.

  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.

  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.

AUTHOR
Copyright 2003-2010, Phil Harvey

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

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

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