1

#!/usr/bin/env python

     2

# -*- coding: utf-8 -*-

     3

     4

"""

     5

    EXIF file format data, including tag names, types, etc.

     6

     7

    Most of this was copied with modifications from EXIFpy:

     8

        # Library to extract EXIF information from digital camera image files

     9

        # http://sourceforge.net/projects/exif-py/

    10

        #

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        # VERSION 1.1.0

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        #

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        # Copyright (c) 2002-2007 Gene Cash All rights reserved

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        # Copyright (c) 2007-2008 Ianaré Sévi All rights reserved

    15

        #

    16

        # Redistribution and use in source and binary forms, with or without

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        # modification, are permitted provided that the following conditions

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        # are met:

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        #

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        #  1. Redistributions of source code must retain the above copyright

    21

        #     notice, this list of conditions and the following disclaimer.

    22

        #

    23

        #  2. Redistributions in binary form must reproduce the above

    24

        #     copyright notice, this list of conditions and the following

    25

        #     disclaimer in the documentation and/or other materials provided

    26

        #     with the distribution.

    27

        #

    28

        #  3. Neither the name of the authors nor the names of its contributors

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        #     may be used to endorse or promote products derived from this

    30

        #     software without specific prior written permission.

    31

        #

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        # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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        # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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        # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

    35

        # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

    36

        # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    37

        # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

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        # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

    39

        # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

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        # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

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        # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

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        # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    43

    44

"""

    45

    46

import decimal, itertools

    47

    48

def filter_ascii (values) :

    49

    """

    50

        Default post-filter for ASCII values.

    51

    52

        This takes a single item of string data, splits it up into strings by ASCII-NUL.

    53

    54

        These sub-strings are then decoded into unicode as ASCII, and stripped.

    55

    """

    56

    57

    return [string.decode('ascii', 'replace').rstrip() for string in values[0].split('\x00') if string]

    58

    59

def build_ratio (num, denom) :

    60

    """

    61

        Builds a Decimal ratio out of the given numerator and denominator

    62

    """

    63

    64

    # XXX: this may be slow

    65

    return decimal.Decimal(num) / decimal.Decimal(denom)

    66

    67

def filter_ratio (values) :

    68

    """

    69

        Default post-filter for Ratio values.

    70

    71

        This takes the pairs of numerator/denominator values and builds Decimals out of them

    72

    """

    73

    74

    return [build_ratio(values[i], values[i + 1]) for i in xrange(0, len(values), 2)]

    75

    76

    77

# IFD Tag type information, indexed by code

    78

#  { type_code: (type_fmt, name, filter_func) }

    79

#

    80

# type_fmt's that are one char will be prefixed with the count for use with struct.unpack, those with more chars will

    81

# be repeated as many times for use with struct.unpack.

    82

FIELD_TYPES = {

    83

#    0x0000: (None,  'Proprietary'   ), # ??? no such type

    84

    0x0001: ('B',   'Byte',         None            ),

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    0x0002: ('s',   'ASCII',        filter_ascii    ),

    86

    0x0003: ('H',   'Short',        None            ),

    87

    0x0004: ('L',   'Long',         None            ),

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    0x0005: ('LL',  'Ratio',        filter_ratio    ),

    89

    0x0006: ('b',   'Signed Byte',  None            ),

    90

    0x0007: ('s',   'Undefined',    None            ),

    91

    0x0008: ('h',   'Signed Short', None            ),

    92

    0x0009: ('l',   'Signed Long',  None            ),

    93

    0x000A: ('ll',  'Signed Ratio', filter_ratio    ),

    94

}

    95

    96

# magic value to indicate sub-IFDs

    97

SUB_IFD_MAGIC = object()

    98

    99

   100

class Tag (object) :

   101

    """

   102

        Represents an Exif Tag

   103

    """

   104

   105

    def __init__ (self, name) :

   106

        """

   107

            Build Exif tag with given name, and optional external values-filter function.

   108

        """

   109

   110

        self.name = name

   111

   112

    def map_values (self, values) :

   113

        """

   114

            Map the given tag value to a printable string using the given value spec.

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        """

   116

   117

        # default value-mapping

   118

        return ", ".join(str(value) for value in values)

   119

   120

class TagDict (Tag) :

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    """

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        A tag with a dict mapping values to names

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    """

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    def __init__ (self, name, values_dict) :

   126

        super(TagDict, self).__init__(name)

   127

   128

        self.values_dict = values_dict

   129

   130

    def map_values (self, values) :

   131

        """

   132

            Map the values through our dict, defaulting to the repr.

   133

        """

   134

   135

        return ", ".join(self.values_dict.get(value, repr(value)) for value in values)

   136

   137

class TagFunc (Tag) :

   138

    """

   139

        A tag with a simple function mapping values to names

   140

    """

   141

   142

    def __init__ (self, name, values_func) :

   143

        super(TagFunc, self).__init__(name)

   144

   145

        self.values_func = values_func

   146

   147

    def map_values (self, values) :

   148

        """

   149

            Map the values through our func

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        """

   151

   152

        return self.values_func(values)

   153

   154

class IFDTag (Tag) :

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    """

   156

        A tag that references another IFD

   157

    """

   158

   159

    def __init__ (self, name, ifd_tags=None) :

   160

        """

   161

            A tag that points to another IFD block. `ifd_tags`, if given, lists the tags for that block, otherwise,

   162

            the same tags as for the current block are used.

   163

        """

   164

   165

        super(IFDTag, self).__init__(name)

   166

   167

        self.ifd_tags = ifd_tags

   168

   169

USER_COMMENT_CHARSETS = {

   170

    'ASCII':    ('ascii',   'replace'   ),

   171

    'JIS':      ('jis',     'error'     ),

   172

   173

    # XXX: WTF? What kind of charset is 'Unicode' supposed to be?

   174

    # UTF-16? Little-endian? Big-endian?

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    # Confusing reigns: http://www.cpanforum.com/threads/7329

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    'UNICODE':  ('utf16',   'error'     ),

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}

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   179

   180

def decode_UserComment (values) :

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    """

   182

        A UserComment field starts with an eight-byte encoding designator.

   183

    """

   184

   185

    # single binary string

   186

    value, = values

   187

   188

    # split up

   189

    charset, comment_raw = value[:8], value[8:]

   190

   191

    # strip NILs

   192

    charset = charset.rstrip('\x00')

   193

   194

    # map

   195

    encoding, replace = USER_COMMENT_CHARSETS.get(charset, ('ascii', 'replace'))

   196

   197

    # decode

   198

    return [comment_raw.decode(encoding, replace)]

   199

   200

# Mappings of Exif tag codes to name and decoding information.

   201

# { tag : (name, value_dict/value_func/None/SUB_IFD_MAGIC) }

   202

#

   203

# name is the official Exif tag name

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# value_dict is a { value: value_name } mapping for human-readable values

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# value_func is a `(values) -> values` mapping function which *overrides* the tag's type_func.

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#   XXX: or does it?

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# SUB_IFD_MAGIC signifies that this IFD points to 

   208

# otherwise, the value is left as-is.

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# interoperability tags

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INTR_TAGS = {

   211

    0x0001: Tag('InteroperabilityIndex'),

   212

    0x0002: Tag('InteroperabilityVersion'),

   213

    0x1000: Tag('RelatedImageFileFormat'),

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    0x1001: Tag('RelatedImageWidth'),

   215

    0x1002: Tag('RelatedImageLength'),

   216

    }

   217

   218

# GPS tags (not used yet, haven't seen camera with GPS)

   219

GPS_TAGS = {

   220

    0x0000: Tag('GPSVersionID'),

   221

    0x0001: Tag('GPSLatitudeRef'),

   222

    0x0002: Tag('GPSLatitude'),

   223

    0x0003: Tag('GPSLongitudeRef'),

   224

    0x0004: Tag('GPSLongitude'),

   225

    0x0005: Tag('GPSAltitudeRef'),

   226

    0x0006: Tag('GPSAltitude'),

   227

    0x0007: Tag('GPSTimeStamp'),

   228

    0x0008: Tag('GPSSatellites'),

   229

    0x0009: Tag('GPSStatus'),

   230

    0x000A: Tag('GPSMeasureMode'),

   231

    0x000B: Tag('GPSDOP'),

   232

    0x000C: Tag('GPSSpeedRef'),

   233

    0x000D: Tag('GPSSpeed'),

   234

    0x000E: Tag('GPSTrackRef'),

   235

    0x000F: Tag('GPSTrack'),

   236

    0x0010: Tag('GPSImgDirectionRef'),

   237

    0x0011: Tag('GPSImgDirection'),

   238

    0x0012: Tag('GPSMapDatum'),

   239

    0x0013: Tag('GPSDestLatitudeRef'),

   240

    0x0014: Tag('GPSDestLatitude'),

   241

    0x0015: Tag('GPSDestLongitudeRef'),

   242

    0x0016: Tag('GPSDestLongitude'),

   243

    0x0017: Tag('GPSDestBearingRef'),

   244

    0x0018: Tag('GPSDestBearing'),

   245

    0x0019: Tag('GPSDestDistanceRef'),

   246

    0x001A: Tag('GPSDestDistance'),

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    0x001D: Tag('GPSDate'),

   248

    }

   249

   250

   251

EXIF_TAGS = {

   252

    0x0100: Tag('ImageWidth'),

   253

    0x0101: Tag('ImageLength'),

   254

    0x0102: Tag('BitsPerSample'),

   255

    0x0103: TagDict('Compression',

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             {1: 'Uncompressed',

   257

              2: 'CCITT 1D',

   258

              3: 'T4/Group 3 Fax',

   259

              4: 'T6/Group 4 Fax',

   260

              5: 'LZW',

   261

              6: 'JPEG (old-style)',

   262

              7: 'JPEG',

   263

              8: 'Adobe Deflate',

   264

              9: 'JBIG B&W',

   265

              10: 'JBIG Color',

   266

              32766: 'Next',

   267

              32769: 'Epson ERF Compressed',

   268

              32771: 'CCIRLEW',

   269

              32773: 'PackBits',

   270

              32809: 'Thunderscan',

   271

              32895: 'IT8CTPAD',

   272

              32896: 'IT8LW',

   273

              32897: 'IT8MP',

   274

              32898: 'IT8BL',

   275

              32908: 'PixarFilm',

   276

              32909: 'PixarLog',

   277

              32946: 'Deflate',

   278

              32947: 'DCS',

   279

              34661: 'JBIG',

   280

              34676: 'SGILog',

   281

              34677: 'SGILog24',

   282

              34712: 'JPEG 2000',

   283

              34713: 'Nikon NEF Compressed',

   284

              65000: 'Kodak DCR Compressed',

   285

              65535: 'Pentax PEF Compressed'}),

   286

    0x0106: Tag('PhotometricInterpretation'),

   287

    0x0107: Tag('Thresholding'),

   288

    0x010A: Tag('FillOrder'),

   289

    0x010D: Tag('DocumentName'),

   290

    0x010E: Tag('ImageDescription'),

   291

    0x010F: Tag('Make'),

   292

    0x0110: Tag('Model'),

   293

    0x0111: Tag('StripOffsets'),

   294

    0x0112: TagDict('Orientation',

   295

             {1: 'Horizontal (normal)',

   296

              2: 'Mirrored horizontal',

   297

              3: 'Rotated 180',

   298

              4: 'Mirrored vertical',

   299

              5: 'Mirrored horizontal then rotated 90 CCW',

   300

              6: 'Rotated 90 CW',

   301

              7: 'Mirrored horizontal then rotated 90 CW',

   302

              8: 'Rotated 90 CCW'}),

   303

    0x0115: Tag('SamplesPerPixel'),

   304

    0x0116: Tag('RowsPerStrip'),

   305

    0x0117: Tag('StripByteCounts'),

   306

    0x011A: Tag('XResolution'),

   307

    0x011B: Tag('YResolution'),

   308

    0x011C: Tag('PlanarConfiguration'),

   309

    0x011D: Tag('PageName'),

   310

    0x0128: TagDict('ResolutionUnit',

   311

             {1: 'Not Absolute',

   312

              2: 'Pixels/Inch',

   313

              3: 'Pixels/Centimeter'}),

   314

    0x012D: Tag('TransferFunction'),

   315

    0x0131: Tag('Software'),

   316

    0x0132: Tag('DateTime'),

   317

    0x013B: Tag('Artist'),

   318

    0x013E: Tag('WhitePoint'),

   319

    0x013F: Tag('PrimaryChromaticities'),

   320

    0x0156: Tag('TransferRange'),

   321

    0x0200: Tag('JPEGProc'),

   322

    0x0201: Tag('JPEGInterchangeFormat'),

   323

    0x0202: Tag('JPEGInterchangeFormatLength'),

   324

    0x0211: Tag('YCbCrCoefficients'),

   325

    0x0212: Tag('YCbCrSubSampling'),

   326

    0x0213: TagDict('YCbCrPositioning',

   327

             {1: 'Centered',

   328

              2: 'Co-sited'}),

   329

    0x0214: Tag('ReferenceBlackWhite'),

   330

   331

    0x4746: Tag('Rating'),

   332

   333

    0x828D: Tag('CFARepeatPatternDim'),

   334

    0x828E: Tag('CFAPattern'),

   335

    0x828F: Tag('BatteryLevel'),

   336

    0x8298: Tag('Copyright'),

   337

    0x829A: Tag('ExposureTime'),

   338

    0x829D: Tag('FNumber'),

   339

    0x83BB: Tag('IPTC/NAA'),

   340

    0x8769: IFDTag('ExifOffset', None),

   341

    0x8773: Tag('InterColorProfile'),

   342

    0x8822: TagDict('ExposureProgram',

   343

             {0: 'Unidentified',

   344

              1: 'Manual',

   345

              2: 'Program Normal',

   346

              3: 'Aperture Priority',

   347

              4: 'Shutter Priority',

   348

              5: 'Program Creative',

   349

              6: 'Program Action',

   350

              7: 'Portrait Mode',

   351

              8: 'Landscape Mode'}),

   352

    0x8824: Tag('SpectralSensitivity'),

   353

    0x8825: IFDTag('GPSInfo', GPS_TAGS),

   354

    0x8827: Tag('ISOSpeedRatings'),

   355

    0x8828: Tag('OECF'),

   356

    0x9000: Tag('ExifVersion'),

   357

    0x9003: Tag('DateTimeOriginal'),

   358

    0x9004: Tag('DateTimeDigitized'),

   359

    0x9101: TagDict('ComponentsConfiguration',

   360

             {0: '',

   361

              1: 'Y',

   362

              2: 'Cb',

   363

              3: 'Cr',

   364

              4: 'Red',

   365

              5: 'Green',

   366

              6: 'Blue'}),

   367

    0x9102: Tag('CompressedBitsPerPixel'),

   368

    0x9201: Tag('ShutterSpeedValue'),

   369

    0x9202: Tag('ApertureValue'),

   370

    0x9203: Tag('BrightnessValue'),

   371

    0x9204: Tag('ExposureBiasValue'),

   372

    0x9205: Tag('MaxApertureValue'),

   373

    0x9206: Tag('SubjectDistance'),

   374

    0x9207: TagDict('MeteringMode',

   375

             {0: 'Unidentified',

   376

              1: 'Average',

   377

              2: 'CenterWeightedAverage',

   378

              3: 'Spot',

   379

              4: 'MultiSpot',

   380

              5: 'Pattern'}),

   381

    0x9208: TagDict('LightSource',

   382

             {0: 'Unknown',

   383

              1: 'Daylight',

   384

              2: 'Fluorescent',

   385

              3: 'Tungsten',

   386

              9: 'Fine Weather',

   387

              10: 'Flash',

   388

              11: 'Shade',

   389

              12: 'Daylight Fluorescent',

   390

              13: 'Day White Fluorescent',

   391

              14: 'Cool White Fluorescent',

   392

              15: 'White Fluorescent',

   393

              17: 'Standard Light A',

   394

              18: 'Standard Light B',

   395

              19: 'Standard Light C',

   396

              20: 'D55',

   397

              21: 'D65',

   398

              22: 'D75',

   399

              255: 'Other'}),

   400

    0x9209: TagDict('Flash',

   401

             {0: 'No',

   402

              1: 'Fired',

   403

              5: 'Fired (?)', # no return sensed

   404

              7: 'Fired (!)', # return sensed

   405

              9: 'Fill Fired',

   406

              13: 'Fill Fired (?)',

   407

              15: 'Fill Fired (!)',

   408

              16: 'Off',

   409

              24: 'Auto Off',

   410

              25: 'Auto Fired',

   411

              29: 'Auto Fired (?)',

   412

              31: 'Auto Fired (!)',

   413

              32: 'Not Available'}),

   414

    0x920A: Tag('FocalLength'),

   415

    0x9214: Tag('SubjectArea'),

   416

    0x927C: Tag('MakerNote'),

   417

    0x9286: TagFunc('UserComment', decode_UserComment),

   418

    0x9290: Tag('SubSecTime'),

   419

    0x9291: Tag('SubSecTimeOriginal'),

   420

    0x9292: Tag('SubSecTimeDigitized'),

   421

   422

    # used by Windows Explorer

   423

    0x9C9B: Tag('XPTitle'),

   424

    0x9C9C: Tag('XPComment'),

   425

    0x9C9D: Tag('XPAuthor'), #(ignored by Windows Explorer if Artist exists)

   426

    0x9C9E: Tag('XPKeywords'),

   427

    0x9C9F: Tag('XPSubject'),

   428

   429

    0xA000: Tag('FlashPixVersion'),

   430

    0xA001: TagDict('ColorSpace',

   431

             {1: 'sRGB',

   432

              2: 'Adobe RGB',

   433

              65535: 'Uncalibrated'}),

   434

    0xA002: Tag('ExifImageWidth'),

   435

    0xA003: Tag('ExifImageLength'),

   436

    0xA005: IFDTag('InteroperabilityOffset', INTR_TAGS),

   437

    0xA20B: Tag('FlashEnergy'),               # 0x920B in TIFF/EP

   438

    0xA20C: Tag('SpatialFrequencyResponse'),  # 0x920C

   439

    0xA20E: Tag('FocalPlaneXResolution'),     # 0x920E

   440

    0xA20F: Tag('FocalPlaneYResolution'),     # 0x920F

   441

    0xA210: Tag('FocalPlaneResolutionUnit'),  # 0x9210

   442

    0xA214: Tag('SubjectLocation'),           # 0x9214

   443

    0xA215: Tag('ExposureIndex'),             # 0x9215

   444

    0xA217: TagDict('SensingMethod',                # 0x9217

   445

             {1: 'Not defined',

   446

              2: 'One-chip color area',

   447

              3: 'Two-chip color area',

   448

              4: 'Three-chip color area',

   449

              5: 'Color sequential area',

   450

              7: 'Trilinear',

   451

              8: 'Color sequential linear'}),             

   452

    0xA300: TagDict('FileSource',

   453

             {1: 'Film Scanner',

   454

              2: 'Reflection Print Scanner',

   455

              3: 'Digital Camera'}),

   456

    0xA301: TagDict('SceneType',

   457

             {1: 'Directly Photographed'}),

   458

    0xA302: Tag('CVAPattern'),

   459

    0xA401: TagDict('CustomRendered',

   460

             {0: 'Normal',

   461

              1: 'Custom'}),

   462

    0xA402: TagDict('ExposureMode',

   463

             {0: 'Auto Exposure',

   464

              1: 'Manual Exposure',

   465

              2: 'Auto Bracket'}),

   466

    0xA403: TagDict('WhiteBalance',

   467

             {0: 'Auto',

   468

              1: 'Manual'}),

   469

    0xA404: Tag('DigitalZoomRatio'),

   470

    0xA405: ('FocalLengthIn35mmFilm', None),

   471

    0xA406: TagDict('SceneCaptureType',

   472

             {0: 'Standard',

   473

              1: 'Landscape',

   474

              2: 'Portrait',

   475

              3: 'Night)'}),

   476

    0xA407: TagDict('GainControl',

   477

             {0: 'None',

   478

              1: 'Low gain up',

   479

              2: 'High gain up',

   480

              3: 'Low gain down',

   481

              4: 'High gain down'}),

   482

    0xA408: TagDict('Contrast',

   483

             {0: 'Normal',

   484

              1: 'Soft',

   485

              2: 'Hard'}),

   486

    0xA409: TagDict('Saturation',

   487

             {0: 'Normal',

   488

              1: 'Soft',

   489

              2: 'Hard'}),

   490

    0xA40A: TagDict('Sharpness',

   491

             {0: 'Normal',

   492

              1: 'Soft',

   493

              2: 'Hard'}),

   494

    0xA40B: Tag('DeviceSettingDescription'),

   495

    0xA40C: Tag('SubjectDistanceRange'),

   496

    0xA500: Tag('Gamma'),

   497

    0xC4A5: Tag('PrintIM'),

   498

    0xEA1C:	('Padding', None),

   499

    }

   500

   501

# http://tomtia.plala.jp/DigitalCamera/MakerNote/index.asp

   502

def nikon_ev_bias (seq) :

   503