Basic Usage for an Exif File

require'file_data'## Step 1: Read in the exif data using either a file path or a stream# Using a file path...file_path='/home/user/desktop/my_file.jpg'# Path to an exif fileexif_data=FileData::Exif.all_data(file_path)# read in all of the exif data from the file path# Or using a stream...exif_data=File.open(file_path,'rb')do |f|FileData::Exif.all_data(f)end## Step 2: Data is divided into image data and thumbnail data. Pick which you want to work with.# Both objects are hash-like and should respond to all hash method except .length which instead will return the value of :Image_Structure_Length,image_data=exif_data.imagethumbnail_data=exif_data.thumbnail## Step 3: Extract the tag values### Step 3A: Extract tags with a known name (ones that are listed in the "Known Tag Keys" section below)# Convenience methods are added for the names after the last underscore in the known tag names (casing and underscores are ignored in the convenince method names)bits_per_sample=image_data.BitsPerSample# Gets :Image_Structure_BitsPerSample from the :Tiff sectionbits_per_sample=image_data.bits_per_sample# Also gets :Image_Structure_BitsPerSample from the :Tiff section### Step 3B: Extract tags without a known name (ones NOT listed in the "Known Tag Keys" section below)# Use the format "#{ifd_id}-#{tag_id}" for the unknown tag to key into the dataunknown_gps_tag_value=image_data["34853-99999"]

Known Tag Keys

# Tiff Tags (0th and 1st IFDs)FileData::ExifTags.tag_groups[:Tiff]={256=>:Image_Structure_Width,257=>:Image_Structure_Length,258=>:Image_Structure_BitsPerSample,259=>:Image_Structure_Compression,262=>:Image_Structure_PhotometricInterpretation,270=>:Other_ImageDescription,271=>:Other_Make,272=>:Other_Model,273=>:Recording_StripOffsets,274=>:Image_Structure_Orientation,277=>:Image_Structure_SamplesPerPixel,278=>:Recording_RowsPerStrip,279=>:Recording_StripByteCounts,283=>:Image_Structure_YResolution,284=>:Image_Structure_PlanarConfiguration,296=>:Image_Structure_ResolutionUnit,301=>:Image_Data_TransferFunction,305=>:Other_Software,306=>:Other_DateTime,315=>:Other_Artist,318=>:Image_Data_WhitePoint,319=>:Image_Data_PrimaryChromaticities,513=>:Recording_JPEGInterchangeFormat,514=>:Recording_JPEGInterchangeFormatLength,529=>:Image_Data_YCbCrCoefficients,530=>:Image_Structure_YCbCrSubSampling,531=>:Image_Structure_YCbCrPositioning,532=>:Image_Data_ReferenceBlackWhite,33_432=>:Other_Copyright}# Exif IFD TagsFileData::ExifTags.tag_groups[34_665]={33_434=>:Exif_PictureTakingConditions_ExposureTime,33_437=>:Exif_PictureTakingConditions_FNumber,34_850=>:Exif_PictureTakingConditions_ExposureProgram,34_852=>:Exif_PictureTakingConditions_SpectralSensitivity,34_855=>:Exif_PictureTakingConditions_PhotographicSensitivity,34_856=>:Exif_PictureTakingConditions_OECF,34_864=>:Exif_PictureTakingConditions_SensitivityType,34_865=>:Exif_PictureTakingConditions_StandardOutputSensitivity,34_866=>:Exif_PictureTakingConditions_RecommendedExposureIndex,34_867=>:Exif_PictureTakingConditions_ISOSpeed,34_868=>:Exif_PictureTakingConditions_ISOSpeedLatitudeyyy,34_869=>:Exif_PictureTakingConditions_ISOSpeedLatitudezzz,36_864=>:Exif_Version_ExifVersion,36_867=>:Exif_DateAndTime_DateTimeOriginal,36_868=>:Exif_DateAndTime_DateTimeDigitized,37_121=>:Exif_Configuration_ComponentsConfiguration,37_122=>:Exif_Configuration_CompressedBitsPerPixel,37_377=>:Exif_PictureTakingConditions_ShutterSpeedValue,37_378=>:Exif_PictureTakingConditions_ApertureValue,37_379=>:Exif_PictureTakingConditions_BrightnessValue,37_380=>:Exif_PictureTakingConditions_ExposureBiasValue,37_381=>:Exif_PictureTakingConditions_MaxApertureValue,37_382=>:Exif_PictureTakingConditions_SubjectDistance,37_383=>:Exif_PictureTakingConditions_MeteringMode,37_384=>:Exif_PictureTakingConditions_LightSource,37_385=>:Exif_PictureTakingConditions_Flash,37_396=>:Exif_PictureTakingConditions_SubjectArea,37_386=>:Exif_PictureTakingConditions_FocalLength,37_500=>:Exif_Configuration_MakerNote,37_510=>:Exif_Configuration_UserComment,37_520=>:Exif_DateAndTime_SubsecTime,37_521=>:Exif_DateAndTime_SubsecTimeOriginal,37_522=>:Exif_DateAndTime_SubsecTimeDigitized,37_888=>:Exif_ShootingSituation_Temperature,37_889=>:Exif_ShootingSituation_Humidity,37_890=>:Exif_ShootingSituation_Pressure,37_891=>:Exif_ShootingSituation_WaterDepth,37_892=>:Exif_ShootingSituation_Acceleration,37_893=>:Exif_ShootingSituation_CameraElevationAngle,40_960=>:Exif_Version_FlashpixVersion,40_961=>:Exif_ColorSpace_ColorSpace,40_962=>:Exif_Configuration_PixelXDimension,40_963=>:Exif_Configuration_PixelYDimension,40_964=>:Exif_RelatedFile_RelatedSoundFile,41_483=>:Exif_PictureTakingConditions_FlashEnergy,41_484=>:Exif_PictureTakingConditions_SpatialFrequencyResponse,41_486=>:Exif_PictureTakingConditions_FocalPlaneXResolution,41_487=>:Exif_PictureTakingConditions_FocalPlaneYResolution,41_488=>:Exif_PictureTakingConditions_FocalPlanResolutionUnit,41_492=>:Exif_PictureTakingConditions_SubjectLocation,41_493=>:Exif_PictureTakingConditions_ExposureIndex,41_495=>:Exif_PictureTakingConditions_SensingMode,41_728=>:Exif_PictureTakingConditions_FileSource,41_729=>:Exif_PictureTakingConditions_SceneType,41_730=>:Exif_PictureTakingConditions_CFAPattern,41_985=>:Exif_PictureTakingConditions_CustomRendered,41_986=>:Exif_PictureTakingConditions_ExposureMode,41_987=>:Exif_PictureTakingConditions_WhiteBalance,41_988=>:Exif_PictureTakingConditions_DigitalZoomRatio,41_989=>:Exif_PictureTakingConditions_FocalLengthIn35mmFilm,41_990=>:Exif_PictureTakingConditions_SceneCaptureType,41_991=>:Exif_PictureTakingConditions_GainControl,41_992=>:Exif_PictureTakingConditions_Contrast,41_993=>:Exif_PictureTakingConditions_Saturation,41_994=>:Exif_PictureTakingConditions_Sharpness,41_995=>:Exif_PictureTakingConditions_DeviceSettingDescription,41_996=>:Exif_PictureTakingConditions_SubjectDistanceRange,42_016=>:Exif_Other_ImageUniqueID,42_032=>:Exif_Other_CameraOwnerName,42_033=>:Exif_Other_BodySerialNumber,42_034=>:Exif_Other_LensSpecification,42_035=>:Exif_Other_LensMake,42_036=>:Exif_Other_LensModel,42_037=>:Exif_Other_LensSerialNumber,42_240=>:Exif_ColorSpace_Gamma}# GPS IFD TagsFileData::ExifTags.tag_groups[34_853]={0=>:GPS_Version,1=>:GPS_LatitudeRef,2=>:GPS_Latitude,3=>:GPS_LongitudeRef,4=>:GPS_Longitude,5=>:GPS_AltitudeRef,6=>:GPS_Altitude,7=>:GPS_TimeStamp,8=>:GPS_Satellites,9=>:GPS_Status,10=>:GPS_MeasureMode,11=>:GPS_DOP,12=>:GPS_SpeedRef,13=>:GPS_Speed,14=>:GPS_TrackRef,15=>:GPS_Track,16=>:GPS_ImgDirectionRef,17=>:GPS_ImgDirection,18=>:GPS_MapDatum,19=>:GPS_DestLatitudeRef,20=>:GPS_DestLatitude,21=>:GPS_DestLongitudeRef,22=>:GPS_DestLongitude,23=>:GPS_DestBearingRef,24=>:GPS_DestBearing,25=>:GPS_DestDistanceRef,26=>:GPS_DestDistance,27=>:GPS_ProcessingMethod,28=>:GPS_AreaInformation,29=>:GPS_DateStamp,30=>:GPS_Differential,31=>:GPS_HPositioningError}# Interoperability IFD TagsFileData::ExifTags.tag_groups[40_965]={1=>:Interoperability_Index}

Mpeg4 documentation

filepath='...'# path to an mpeg4 fileFile.open(filepath,'rb')do |stream|parser=FileData::MvhdBoxParser# class that parses the box you wantmethod=:creation_time# attribute to get from the parse resultbox_path=['moov','mvhd']# path to get to the box that you want# final result that you are looking forresult=FileData::Mpeg4.get_value(stream,parser,method, *box_path)end