Exif Data StructureĪ Rough structure of EXIF data (APP1) is shown as below. After the APP1 Marker area, the other JPEG Markers follows. The first part is a special data for the identification whether EXIF or not, ASCII character “EXIF” and 2 bytes of 0x00 are used. Please notice that the size “SSSS” includes the size of descriptor itself also. After the “SSSS”, APP1 data starts. The part of “SSSS” on upper table means the size of APP1 data area (EXIF data area). All the data of EXIF are stored in this APP1 data area. It starts from SOI (0xFFD8) Marker, so it’s a JPEG file. Every EXIF file formats starts from this format. Furthermore, EXIF also uses an Application Marker for inserting data, but EXIF uses APP1 (0xFFE1) Marker to avoid a conflict with JFIF format. JFIF uses APP0 (0xFFE0) Marker for inserting digi cam configuration data and thumbnail image. For example, older digi cams use JFIF (JPEG File Interchange Format) for storing images. The marker 0xFFE0~~0xFFEF is “Application Marker”, used by user application. RIFF WAV for audio files (Linear PCM or ITU-T G.711 μ-Law PCM for uncompressed audio data, and IMA- ADPCM for compressed audio data).6.0 (RGB or YCbCr) for uncompressed image files. JPEG - discrete cosine transform (DCT) for compressed image files.September 2003, Version 2.21 with optional colour space known as adobe RGB.ĮXIF uses the following file formats with the addition of specific metadata.February 2002, Version 2.2, improved version 2.1 with the addition of print finishing.December 1998, Version 2.1 with enhanced storage and attribute information.June 1998, Version 2 with sRGB colour space, compressed thumbnails and audio files.Nov 1997, version 1.1 was introduced with most of the tags from version 1 but also added provisions for optional attribute information and format operation.In this version JEIDA defined the structure, which consists of image data format and attribute information, and basic tags. In Oct 1995, JEIDA established Version 1.Exif metadata may also include thumbnails along with technical and primary image data in a single image file. In order to view the EXIF data, one has to select the view properties within image viewing application. Normally the EXIF data is hidden by default. Metadata can contain information like camera model, shutter speed, Date and time, aperture, manufacturer, exposure time, X resolution, Y resolution etc. EXIF is a standard for the specifications of image and sound formats mainly used by digital cameras and scanners.ĮXIF standard includes the tagging and metadata information with the image file. The standard is managed by Japan Electronics and Information Technology Industries Association (JEITA) as of today. EXIF stands for “Exchangeable Image File Format”, the definition first given by Japan Camera Industry Association (JCIA) in 1985.
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