This page hosts a formal specification of exif using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
import kaitai_struct_nim_runtime
import options
type
Exif* = ref object of KaitaiStruct
`endianness`*: uint16
`body`*: Exif_ExifBody
`parent`*: KaitaiStruct
Exif_ExifBody* = ref object of KaitaiStruct
`version`*: uint16
`ifd0Ofs`*: uint32
`parent`*: Exif
`ifd0Inst`: Exif_ExifBody_Ifd
`ifd0InstFlag`: bool
isLe: bool
Exif_ExifBody_Ifd* = ref object of KaitaiStruct
`numFields`*: uint16
`fields`*: seq[Exif_ExifBody_IfdField]
`nextIfdOfs`*: uint32
`parent`*: KaitaiStruct
`nextIfdInst`: Exif_ExifBody_Ifd
`nextIfdInstFlag`: bool
isLe: bool
Exif_ExifBody_IfdField* = ref object of KaitaiStruct
`tag`*: Exif_ExifBody_IfdField_TagEnum
`fieldType`*: Exif_ExifBody_IfdField_FieldTypeEnum
`length`*: uint32
`ofsOrData`*: uint32
`parent`*: Exif_ExifBody_Ifd
`typeByteLengthInst`: int8
`typeByteLengthInstFlag`: bool
`byteLengthInst`: int
`byteLengthInstFlag`: bool
`isImmediateDataInst`: bool
`isImmediateDataInstFlag`: bool
`dataInst`: seq[byte]
`dataInstFlag`: bool
isLe: bool
Exif_ExifBody_IfdField_FieldTypeEnum* = enum
byte = 1
ascii_string = 2
word = 3
dword = 4
rational = 5
undefined = 7
slong = 9
srational = 10
Exif_ExifBody_IfdField_TagEnum* = enum
image_width = 256
image_height = 257
bits_per_sample = 258
compression = 259
photometric_interpretation = 262
thresholding = 263
cell_width = 264
cell_length = 265
fill_order = 266
document_name = 269
image_description = 270
make = 271
model = 272
strip_offsets = 273
orientation = 274
samples_per_pixel = 277
rows_per_strip = 278
strip_byte_counts = 279
min_sample_value = 280
max_sample_value = 281
x_resolution = 282
y_resolution = 283
planar_configuration = 284
page_name = 285
x_position = 286
y_position = 287
free_offsets = 288
free_byte_counts = 289
gray_response_unit = 290
gray_response_curve = 291
t4_options = 292
t6_options = 293
resolution_unit = 296
page_number = 297
color_response_unit = 300
transfer_function = 301
software = 305
modify_date = 306
artist = 315
host_computer = 316
predictor = 317
white_point = 318
primary_chromaticities = 319
color_map = 320
halftone_hints = 321
tile_width = 322
tile_length = 323
tile_offsets = 324
tile_byte_counts = 325
bad_fax_lines = 326
clean_fax_data = 327
consecutive_bad_fax_lines = 328
sub_ifd = 330
ink_set = 332
ink_names = 333
numberof_inks = 334
dot_range = 336
target_printer = 337
extra_samples = 338
sample_format = 339
s_min_sample_value = 340
s_max_sample_value = 341
transfer_range = 342
clip_path = 343
x_clip_path_units = 344
y_clip_path_units = 345
indexed = 346
jpeg_tables = 347
opi_proxy = 351
global_parameters_ifd = 400
profile_type = 401
fax_profile = 402
coding_methods = 403
version_year = 404
mode_number = 405
decode = 433
default_image_color = 434
t82_options = 435
jpeg_tables2 = 437
jpeg_proc = 512
thumbnail_offset = 513
thumbnail_length = 514
jpeg_restart_interval = 515
jpeg_lossless_predictors = 517
jpeg_point_transforms = 518
jpegq_tables = 519
jpegdc_tables = 520
jpegac_tables = 521
y_cb_cr_coefficients = 529
y_cb_cr_sub_sampling = 530
y_cb_cr_positioning = 531
reference_black_white = 532
strip_row_counts = 559
application_notes = 700
uspto_miscellaneous = 999
related_image_file_format = 4096
related_image_width = 4097
related_image_height = 4098
rating = 18246
xp_dip_xml = 18247
stitch_info = 18248
rating_percent = 18249
sony_raw_file_type = 28672
light_falloff_params = 28722
chromatic_aberration_corr_params = 28725
distortion_corr_params = 28727
image_id = 32781
wang_tag1 = 32931
wang_annotation = 32932
wang_tag3 = 32933
wang_tag4 = 32934
image_reference_points = 32953
region_xform_tack_point = 32954
warp_quadrilateral = 32955
affine_transform_mat = 32956
matteing = 32995
data_type = 32996
image_depth = 32997
tile_depth = 32998
image_full_width = 33300
image_full_height = 33301
texture_format = 33302
wrap_modes = 33303
fov_cot = 33304
matrix_world_to_screen = 33305
matrix_world_to_camera = 33306
model2 = 33405
cfa_repeat_pattern_dim = 33421
cfa_pattern2 = 33422
battery_level = 33423
kodak_ifd = 33424
copyright = 33432
exposure_time = 33434
f_number = 33437
md_file_tag = 33445
md_scale_pixel = 33446
md_color_table = 33447
md_lab_name = 33448
md_sample_info = 33449
md_prep_date = 33450
md_prep_time = 33451
md_file_units = 33452
pixel_scale = 33550
advent_scale = 33589
advent_revision = 33590
uic1_tag = 33628
uic2_tag = 33629
uic3_tag = 33630
uic4_tag = 33631
iptc_naa = 33723
intergraph_packet_data = 33918
intergraph_flag_registers = 33919
intergraph_matrix = 33920
ingr_reserved = 33921
model_tie_point = 33922
site = 34016
color_sequence = 34017
it8_header = 34018
raster_padding = 34019
bits_per_run_length = 34020
bits_per_extended_run_length = 34021
color_table = 34022
image_color_indicator = 34023
background_color_indicator = 34024
image_color_value = 34025
background_color_value = 34026
pixel_intensity_range = 34027
transparency_indicator = 34028
color_characterization = 34029
hc_usage = 34030
trap_indicator = 34031
cmyk_equivalent = 34032
sem_info = 34118
afcp_iptc = 34152
pixel_magic_jbig_options = 34232
jpl_carto_ifd = 34263
model_transform = 34264
wb_grgb_levels = 34306
leaf_data = 34310
photoshop_settings = 34377
exif_offset = 34665
icc_profile = 34675
tiff_fx_extensions = 34687
multi_profiles = 34688
shared_data = 34689
t88_options = 34690
image_layer = 34732
geo_tiff_directory = 34735
geo_tiff_double_params = 34736
geo_tiff_ascii_params = 34737
jbig_options = 34750
exposure_program = 34850
spectral_sensitivity = 34852
gps_info = 34853
iso = 34855
opto_electric_conv_factor = 34856
interlace = 34857
time_zone_offset = 34858
self_timer_mode = 34859
sensitivity_type = 34864
standard_output_sensitivity = 34865
recommended_exposure_index = 34866
iso_speed = 34867
iso_speed_latitudeyyy = 34868
iso_speed_latitudezzz = 34869
fax_recv_params = 34908
fax_sub_address = 34909
fax_recv_time = 34910
fedex_edr = 34929
leaf_sub_ifd = 34954
exif_version = 36864
date_time_original = 36867
create_date = 36868
google_plus_upload_code = 36873
offset_time = 36880
offset_time_original = 36881
offset_time_digitized = 36882
components_configuration = 37121
compressed_bits_per_pixel = 37122
shutter_speed_value = 37377
aperture_value = 37378
brightness_value = 37379
exposure_compensation = 37380
max_aperture_value = 37381
subject_distance = 37382
metering_mode = 37383
light_source = 37384
flash = 37385
focal_length = 37386
flash_energy = 37387
spatial_frequency_response = 37388
noise = 37389
focal_plane_x_resolution = 37390
focal_plane_y_resolution = 37391
focal_plane_resolution_unit = 37392
image_number = 37393
security_classification = 37394
image_history = 37395
subject_area = 37396
exposure_index = 37397
tiff_ep_standard_id = 37398
sensing_method = 37399
cip3_data_file = 37434
cip3_sheet = 37435
cip3_side = 37436
sto_nits = 37439
maker_note = 37500
user_comment = 37510
sub_sec_time = 37520
sub_sec_time_original = 37521
sub_sec_time_digitized = 37522
ms_document_text = 37679
ms_property_set_storage = 37680
ms_document_text_position = 37681
image_source_data = 37724
ambient_temperature = 37888
humidity = 37889
pressure = 37890
water_depth = 37891
acceleration = 37892
camera_elevation_angle = 37893
xp_title = 40091
xp_comment = 40092
xp_author = 40093
xp_keywords = 40094
xp_subject = 40095
flashpix_version = 40960
color_space = 40961
exif_image_width = 40962
exif_image_height = 40963
related_sound_file = 40964
interop_offset = 40965
samsung_raw_pointers_offset = 40976
samsung_raw_pointers_length = 40977
samsung_raw_byte_order = 41217
samsung_raw_unknown = 41218
flash_energy2 = 41483
spatial_frequency_response2 = 41484
noise2 = 41485
focal_plane_x_resolution2 = 41486
focal_plane_y_resolution2 = 41487
focal_plane_resolution_unit2 = 41488
image_number2 = 41489
security_classification2 = 41490
image_history2 = 41491
subject_location = 41492
exposure_index2 = 41493
tiff_ep_standard_id2 = 41494
sensing_method2 = 41495
file_source = 41728
scene_type = 41729
cfa_pattern = 41730
custom_rendered = 41985
exposure_mode = 41986
white_balance = 41987
digital_zoom_ratio = 41988
focal_length_in35mm_format = 41989
scene_capture_type = 41990
gain_control = 41991
contrast = 41992
saturation = 41993
sharpness = 41994
device_setting_description = 41995
subject_distance_range = 41996
image_unique_id = 42016
owner_name = 42032
serial_number = 42033
lens_info = 42034
lens_make = 42035
lens_model = 42036
lens_serial_number = 42037
gdal_metadata = 42112
gdal_no_data = 42113
gamma = 42240
expand_software = 44992
expand_lens = 44993
expand_film = 44994
expand_filter_lens = 44995
expand_scanner = 44996
expand_flash_lamp = 44997
pixel_format = 48129
transformation = 48130
uncompressed = 48131
image_type = 48132
image_width2 = 48256
image_height2 = 48257
width_resolution = 48258
height_resolution = 48259
image_offset = 48320
image_byte_count = 48321
alpha_offset = 48322
alpha_byte_count = 48323
image_data_discard = 48324
alpha_data_discard = 48325
oce_scanjob_desc = 50215
oce_application_selector = 50216
oce_id_number = 50217
oce_image_logic = 50218
annotations = 50255
print_im = 50341
original_file_name = 50547
uspto_original_content_type = 50560
dng_version = 50706
dng_backward_version = 50707
unique_camera_model = 50708
localized_camera_model = 50709
cfa_plane_color = 50710
cfa_layout = 50711
linearization_table = 50712
black_level_repeat_dim = 50713
black_level = 50714
black_level_delta_h = 50715
black_level_delta_v = 50716
white_level = 50717
default_scale = 50718
default_crop_origin = 50719
default_crop_size = 50720
color_matrix1 = 50721
color_matrix2 = 50722
camera_calibration1 = 50723
camera_calibration2 = 50724
reduction_matrix1 = 50725
reduction_matrix2 = 50726
analog_balance = 50727
as_shot_neutral = 50728
as_shot_white_xy = 50729
baseline_exposure = 50730
baseline_noise = 50731
baseline_sharpness = 50732
bayer_green_split = 50733
linear_response_limit = 50734
camera_serial_number = 50735
dng_lens_info = 50736
chroma_blur_radius = 50737
anti_alias_strength = 50738
shadow_scale = 50739
sr2_private = 50740
maker_note_safety = 50741
raw_image_segmentation = 50752
calibration_illuminant1 = 50778
calibration_illuminant2 = 50779
best_quality_scale = 50780
raw_data_unique_id = 50781
alias_layer_metadata = 50784
original_raw_file_name = 50827
original_raw_file_data = 50828
active_area = 50829
masked_areas = 50830
as_shot_icc_profile = 50831
as_shot_pre_profile_matrix = 50832
current_icc_profile = 50833
current_pre_profile_matrix = 50834
colorimetric_reference = 50879
s_raw_type = 50885
panasonic_title = 50898
panasonic_title2 = 50899
camera_calibration_sig = 50931
profile_calibration_sig = 50932
profile_ifd = 50933
as_shot_profile_name = 50934
noise_reduction_applied = 50935
profile_name = 50936
profile_hue_sat_map_dims = 50937
profile_hue_sat_map_data1 = 50938
profile_hue_sat_map_data2 = 50939
profile_tone_curve = 50940
profile_embed_policy = 50941
profile_copyright = 50942
forward_matrix1 = 50964
forward_matrix2 = 50965
preview_application_name = 50966
preview_application_version = 50967
preview_settings_name = 50968
preview_settings_digest = 50969
preview_color_space = 50970
preview_date_time = 50971
raw_image_digest = 50972
original_raw_file_digest = 50973
sub_tile_block_size = 50974
row_interleave_factor = 50975
profile_look_table_dims = 50981
profile_look_table_data = 50982
opcode_list1 = 51008
opcode_list2 = 51009
opcode_list3 = 51022
noise_profile = 51041
time_codes = 51043
frame_rate = 51044
t_stop = 51058
reel_name = 51081
original_default_final_size = 51089
original_best_quality_size = 51090
original_default_crop_size = 51091
camera_label = 51105
profile_hue_sat_map_encoding = 51107
profile_look_table_encoding = 51108
baseline_exposure_offset = 51109
default_black_render = 51110
new_raw_image_digest = 51111
raw_to_preview_gain = 51112
default_user_crop = 51125
padding = 59932
offset_schema = 59933
owner_name2 = 65000
serial_number2 = 65001
lens = 65002
kdc_ifd = 65024
raw_file = 65100
converter = 65101
white_balance2 = 65102
exposure = 65105
shadows = 65106
brightness = 65107
contrast2 = 65108
saturation2 = 65109
sharpness2 = 65110
smoothness = 65111
moire_filter = 65112
proc read*(_: typedesc[Exif], io: KaitaiStream, root: KaitaiStruct, parent: KaitaiStruct): Exif
proc read*(_: typedesc[Exif_ExifBody], io: KaitaiStream, root: KaitaiStruct, parent: Exif): Exif_ExifBody
proc read*(_: typedesc[Exif_ExifBody_Ifd], io: KaitaiStream, root: KaitaiStruct, parent: KaitaiStruct): Exif_ExifBody_Ifd
proc read*(_: typedesc[Exif_ExifBody_IfdField], io: KaitaiStream, root: KaitaiStruct, parent: Exif_ExifBody_Ifd): Exif_ExifBody_IfdField
proc ifd0*(this: Exif_ExifBody): Exif_ExifBody_Ifd
proc nextIfd*(this: Exif_ExifBody_Ifd): Exif_ExifBody_Ifd
proc typeByteLength*(this: Exif_ExifBody_IfdField): int8
proc byteLength*(this: Exif_ExifBody_IfdField): int
proc isImmediateData*(this: Exif_ExifBody_IfdField): bool
proc data*(this: Exif_ExifBody_IfdField): seq[byte]
proc read*(_: typedesc[Exif], io: KaitaiStream, root: KaitaiStruct, parent: KaitaiStruct): Exif =
template this: untyped = result
this = new(Exif)
let root = if root == nil: cast[Exif](this) else: cast[Exif](root)
this.io = io
this.root = root
this.parent = parent
let endiannessExpr = this.io.readU2le()
this.endianness = endiannessExpr
let bodyExpr = Exif_ExifBody.read(this.io, this.root, this)
this.body = bodyExpr
proc fromFile*(_: typedesc[Exif], filename: string): Exif =
Exif.read(newKaitaiFileStream(filename), nil, nil)
proc readLe(this: Exif_ExifBody) =
let versionExpr = this.io.readU2le()
this.version = versionExpr
let ifd0OfsExpr = this.io.readU4le()
this.ifd0Ofs = ifd0OfsExpr
proc readBe(this: Exif_ExifBody) =
let versionExpr = this.io.readU2be()
this.version = versionExpr
let ifd0OfsExpr = this.io.readU4be()
this.ifd0Ofs = ifd0OfsExpr
proc read*(_: typedesc[Exif_ExifBody], io: KaitaiStream, root: KaitaiStruct, parent: Exif): Exif_ExifBody =
template this: untyped = result
this = new(Exif_ExifBody)
let root = if root == nil: cast[Exif](this) else: cast[Exif](root)
this.io = io
this.root = root
this.parent = parent
this.isLe = false
block:
let on = Exif(this.root).endianness
if on == 18761:
let isLeExpr = bool(true)
this.isLe = isLeExpr
elif on == 19789:
let isLeExpr = bool(false)
this.isLe = isLeExpr
if this.isLe:
readLe(this)
else:
readBe(this)
proc ifd0(this: Exif_ExifBody): Exif_ExifBody_Ifd =
if this.ifd0InstFlag:
return this.ifd0Inst
let pos = this.io.pos()
this.io.seek(int(this.ifd0Ofs))
if this.isLe:
let ifd0InstExpr = Exif_ExifBody_Ifd.read(this.io, this.root, this)
this.ifd0Inst = ifd0InstExpr
else:
let ifd0InstExpr = Exif_ExifBody_Ifd.read(this.io, this.root, this)
this.ifd0Inst = ifd0InstExpr
this.io.seek(pos)
this.ifd0InstFlag = true
return this.ifd0Inst
proc fromFile*(_: typedesc[Exif_ExifBody], filename: string): Exif_ExifBody =
Exif_ExifBody.read(newKaitaiFileStream(filename), nil, nil)
proc readLe(this: Exif_ExifBody_Ifd) =
let numFieldsExpr = this.io.readU2le()
this.numFields = numFieldsExpr
for i in 0 ..< int(this.numFields):
let it = Exif_ExifBody_IfdField.read(this.io, this.root, this)
this.fields.add(it)
let nextIfdOfsExpr = this.io.readU4le()
this.nextIfdOfs = nextIfdOfsExpr
proc readBe(this: Exif_ExifBody_Ifd) =
let numFieldsExpr = this.io.readU2be()
this.numFields = numFieldsExpr
for i in 0 ..< int(this.numFields):
let it = Exif_ExifBody_IfdField.read(this.io, this.root, this)
this.fields.add(it)
let nextIfdOfsExpr = this.io.readU4be()
this.nextIfdOfs = nextIfdOfsExpr
proc read*(_: typedesc[Exif_ExifBody_Ifd], io: KaitaiStream, root: KaitaiStruct, parent: KaitaiStruct): Exif_ExifBody_Ifd =
template this: untyped = result
this = new(Exif_ExifBody_Ifd)
let root = if root == nil: cast[Exif](this) else: cast[Exif](root)
this.io = io
this.root = root
this.parent = parent
this.isLe = this.parent.isLe
if this.isLe:
readLe(this)
else:
readBe(this)
proc nextIfd(this: Exif_ExifBody_Ifd): Exif_ExifBody_Ifd =
if this.nextIfdInstFlag:
return this.nextIfdInst
if this.nextIfdOfs != 0:
let pos = this.io.pos()
this.io.seek(int(this.nextIfdOfs))
if this.isLe:
let nextIfdInstExpr = Exif_ExifBody_Ifd.read(this.io, this.root, this)
this.nextIfdInst = nextIfdInstExpr
else:
let nextIfdInstExpr = Exif_ExifBody_Ifd.read(this.io, this.root, this)
this.nextIfdInst = nextIfdInstExpr
this.io.seek(pos)
this.nextIfdInstFlag = true
return this.nextIfdInst
proc fromFile*(_: typedesc[Exif_ExifBody_Ifd], filename: string): Exif_ExifBody_Ifd =
Exif_ExifBody_Ifd.read(newKaitaiFileStream(filename), nil, nil)
proc readLe(this: Exif_ExifBody_IfdField) =
let tagExpr = Exif_ExifBody_IfdField_TagEnum(this.io.readU2le())
this.tag = tagExpr
let fieldTypeExpr = Exif_ExifBody_IfdField_FieldTypeEnum(this.io.readU2le())
this.fieldType = fieldTypeExpr
let lengthExpr = this.io.readU4le()
this.length = lengthExpr
let ofsOrDataExpr = this.io.readU4le()
this.ofsOrData = ofsOrDataExpr
proc readBe(this: Exif_ExifBody_IfdField) =
let tagExpr = Exif_ExifBody_IfdField_TagEnum(this.io.readU2be())
this.tag = tagExpr
let fieldTypeExpr = Exif_ExifBody_IfdField_FieldTypeEnum(this.io.readU2be())
this.fieldType = fieldTypeExpr
let lengthExpr = this.io.readU4be()
this.length = lengthExpr
let ofsOrDataExpr = this.io.readU4be()
this.ofsOrData = ofsOrDataExpr
proc read*(_: typedesc[Exif_ExifBody_IfdField], io: KaitaiStream, root: KaitaiStruct, parent: Exif_ExifBody_Ifd): Exif_ExifBody_IfdField =
template this: untyped = result
this = new(Exif_ExifBody_IfdField)
let root = if root == nil: cast[Exif](this) else: cast[Exif](root)
this.io = io
this.root = root
this.parent = parent
this.isLe = this.parent.isLe
if this.isLe:
readLe(this)
else:
readBe(this)
proc typeByteLength(this: Exif_ExifBody_IfdField): int8 =
if this.typeByteLengthInstFlag:
return this.typeByteLengthInst
let typeByteLengthInstExpr = int8((if this.fieldType == exif.word: 2 else: (if this.fieldType == exif.dword: 4 else: 1)))
this.typeByteLengthInst = typeByteLengthInstExpr
this.typeByteLengthInstFlag = true
return this.typeByteLengthInst
proc byteLength(this: Exif_ExifBody_IfdField): int =
if this.byteLengthInstFlag:
return this.byteLengthInst
let byteLengthInstExpr = int((this.length * this.typeByteLength))
this.byteLengthInst = byteLengthInstExpr
this.byteLengthInstFlag = true
return this.byteLengthInst
proc isImmediateData(this: Exif_ExifBody_IfdField): bool =
if this.isImmediateDataInstFlag:
return this.isImmediateDataInst
let isImmediateDataInstExpr = bool(this.byteLength <= 4)
this.isImmediateDataInst = isImmediateDataInstExpr
this.isImmediateDataInstFlag = true
return this.isImmediateDataInst
proc data(this: Exif_ExifBody_IfdField): seq[byte] =
if this.dataInstFlag:
return this.dataInst
if not(this.isImmediateData):
let io = Exif(this.root).io
let pos = io.pos()
io.seek(int(this.ofsOrData))
if this.isLe:
let dataInstExpr = io.readBytes(int(this.byteLength))
this.dataInst = dataInstExpr
else:
let dataInstExpr = io.readBytes(int(this.byteLength))
this.dataInst = dataInstExpr
io.seek(pos)
this.dataInstFlag = true
return this.dataInst
proc fromFile*(_: typedesc[Exif_ExifBody_IfdField], filename: string): Exif_ExifBody_IfdField =
Exif_ExifBody_IfdField.read(newKaitaiFileStream(filename), nil, nil)