A Ruby EXIF reader written in C.
$ gem install exif
Please make sure you have installed libexif:
$ brew install libexif # Homebrew
$ sudo apt-get install libexif-dev # APT
$ sudo yum install libexif-devel # CentOS
data = Exif::Data.new(IO.read('sample.jpg')) # load from string
data = Exif::Data.new(File.open('sample.jpg')) # load from file
data.model # => "NIKON D600"
data.image_width # => 4000
data.gps_longitude # => [(121/1), (76869/2500), (0/1)]
data.date_time # => "2013:12:08 21:14:11"
# get all entries in an IFD
data[:ifd0] # => {image_width: 4000, image_length: 2670, ...}
data[:ifd1] # => {x_resolution: (72/1), y_resolution: (72/1), ...}
data[:exif] # => exposure_time: (1/125), fnumber: (8/1)}
data[:gps] # => {gps_version_id: [2, 2, 0, 0], gps_latitude_ref: "N", ...}
data[:interoperability] # => {...}
data.to_h # => {:ifd0 => {...}, :ifd1 => {...}, :exif => {...}}
data.ifds == data.to_h # => trueSince ifd0 and ifd1 share the same domain of tags, sometimes the same tag can be both used inside them, in this case, calling top-level API like Exif::Data#image_width will return the value of ifd0, in other words, ifd0 has higher priority than ifd1.
| Tag Type | Ruby Class |
|---|---|
| ASCII | String |
| BYTE | Integer |
| DOUBLE | Flat |
| FLOAT | Float |
| LONG | Integer |
| RATIONAL | Rational |
| SHORT | Integer |
| UNDEFINED | String |
It's approximately hundreds of times faster than mini_exiftool and exifr.
There are similar excellent works like exifr (by @remvee), and mini_exiftool (by @janfri). They are both built in pure Ruby while this one is C extension.
If you are using JRuby, you might want to take exifr or mini_exiftool a look, the latter lets you get the full power of Exiftool which is written by Phil Harvey since it is a command-line wrapper, otherwise, you can try this gem for performance purpose.
You can find all benchmark files in /benchmark:
$ ruby benchmark/load_file.rb
Rehearsal ---------------------------------------------------------
mini_exiftool (2.8.2) 0.110000 0.050000 10.330000 ( 10.601087)
exifr (1.3.2) 0.040000 0.000000 0.040000 ( 0.045283)
exif (52876a1) 0.010000 0.010000 0.020000 ( 0.018207)
----------------------------------------------- total: 10.390000sec
user system total real
mini_exiftool (2.8.2) 0.100000 0.060000 9.990000 ( 10.256508)
exifr (1.3.2) 0.040000 0.000000 0.040000 ( 0.043715)
exif (52876a1) 0.010000 0.000000 0.010000 ( 0.015512)
-----------------------------------------
661 times faster than mini_exiftool (2.8.2)
3 times faster than exifr (1.3.2)
$ ruby benchmark/read_tag.rb
Rehearsal ---------------------------------------------------------
mini_exiftool (2.8.2) 0.340000 0.000000 0.340000 ( 0.348095)
exifr (1.3.2) 1.040000 0.030000 1.070000 ( 1.068047)
exif (52876a1) 0.010000 0.000000 0.010000 ( 0.006440)
------------------------------------------------ total: 1.420000sec
user system total real
mini_exiftool (2.8.2) 0.320000 0.000000 0.320000 ( 0.321061)
exifr (1.3.2) 1.100000 0.010000 1.110000 ( 1.115179)
exif (52876a1) 0.000000 0.000000 0.000000 ( 0.006496)
-----------------------------------------
49 times faster than mini_exiftool (2.8.2)
172 times faster than exifr (1.3.2)
- aperture_value
- artist
- battery_level
- bits_per_sample
- brightness_value
- cfa_pattern
- cfa_repeat_pattern_dim
- color_space
- components_configuration
- compressed_bits_per_pixel
- compression
- contrast
- copyright
- custom_rendered
- date_time
- date_time_digitized
- date_time_original
- device_setting_description
- digital_zoom_ratio
- document_name
- exif_ifd_pointer
- exif_version
- exposure_bias_value
- exposure_index
- exposure_mode
- exposure_program
- exposure_time
- file_source
- fill_order
- flash
- flash_energy
- flash_pix_version
- fnumber
- focal_length
- focal_length_in_35mm_film
- focal_plane_resolution_unit
- focal_plane_x_resolution
- focal_plane_y_resolution
- gain_control
- gamma
- gps_altitude
- gps_altitude_ref
- gps_area_information
- gps_date_stamp
- gps_dest_bearing
- gps_dest_bearing_ref
- gps_dest_distance
- gps_dest_distance_ref
- gps_dest_latitude
- gps_dest_latitude_ref
- gps_dest_longitude
- gps_dest_longitude_ref
- gps_differential
- gps_dop
- gps_img_direction
- gps_img_direction_ref
- gps_info_ifd_pointer
- gps_latitude
- gps_latitude_ref
- gps_longitude
- gps_longitude_ref
- gps_map_datum
- gps_measure_mode
- gps_processing_method
- gps_satellites
- gps_speed
- gps_speed_ref
- gps_status
- gps_time_stamp
- gps_track
- gps_track_ref
- gps_version_id
- image_description
- image_length
- image_resources
- image_unique_id
- image_width
- inter_color_profile
- interoperability_ifd_pointer
- interoperability_index
- interoperability_version
- iptc_naa
- iso_speed_ratings
- jpeg_interchange_format
- jpeg_interchange_format_length
- jpeg_proc
- light_source
- make
- maker_note
- max_aperture_value
- metering_mode
- model
- new_cfa_pattern
- new_subfile_type
- oecf
- orientation
- padding
- photometric_interpretation
- pixel_x_dimension
- pixel_y_dimension
- planar_configuration
- primary_chromaticities
- print_image_matching
- reference_black_white
- related_image_file_format
- related_image_length
- related_image_width
- related_sound_file
- resolution_unit
- rows_per_strip
- samples_per_pixel
- saturation
- scene_capture_type
- scene_type
- sensing_method
- sharpness
- shutter_speed_value
- software
- spatial_frequency_response
- spectral_sensitivity
- strip_byte_counts
- strip_offsets
- sub_ifds
- sub_sec_time
- sub_sec_time_digitized
- sub_sec_time_original
- subject_area
- subject_distance
- subject_distance_range
- subject_location
- tiff_ep_standard_id
- time_zone_offset
- transfer_function
- transfer_range
- user_comment
- white_balance
- white_point
- x_resolution
- xml_packet
- xp_author
- xp_comment
- xp_keywords
- xp_subject
- xp_title
- y_resolution
- ycbcr_coefficients
- ycbcr_positioning
- ycbcr_sub_sampling
- Create, update and delete tags.