Format
Raw JPEG Stream
Summary
- Name
- Raw JPEG Stream
- Identifiers
-
- Library of Congress Format Description Identifier: fdd000017
- PUID: fmt/41
- MIME: image/jpeg
- Format type
- Image (Raster)
- Description
- Raw JPEG Stream represents JPEG bitstream sequence of digital objects. JPEG stands for Joint Photographic Experts Group, an international organization that standardized the concept of lossy compression during the late 1980s and early 1990s. It uses DCT (Discrete Cosine Transform) compression technique used for images and audio. The standard of lossy compression is able to remove some visual data invisible to human eye which averages out colour variation and reduces the file size. JPEG image consists of a sequence of segments, each beginning with a two-byte "marker", each of which begins with a 0xFF byte, followed by a byte indicating what kind of marker it is. The signature for this entry represents the first two bytes of every JPEG stream, which are the Start Of Image (SOI) marker with values of 0xFF and 0xD8 (indicating that the baseline is DCT-based) and the End of Image (EOI) marker with valued of 0xFF and 0xD9. The second signatures represents the "colour transform" field of the APP14 which is an "Adobe" segment, representing graphic files which may have been edited in Adobe applications such as Adobe Photoshop.
- Note
- https://www.loc.gov/preservation/digital/formats/fdd/fdd000017.shtml#:~:text=The%20Library%20of%20Congress%20Recommended,specify%20a%20version%20of%20JPEG. https://web.archive.org/web/20220624201809/https://www.adobe.com/creativecloud/file-types/image/raster/jpeg-file.html https://web.archive.org/web/20221015163305/https://en.wikipedia.org/wiki/JPEG
- File extensions
-
jpe,jpg,jpeg,jif,jfif,jfi - Source
- Digital Preservation Department / The National Archives
Relationships
- Has lower priority than
-
- JPEG File Interchange Format 1.00
- JPEG File Interchange Format 1.01
- JPEG File Interchange Format 1.02
- Still Picture Interchange File Format 1.0
- Exchangeable Image File Format (Compressed) 2.1
- Exchangeable Image File Format (Compressed) 2.2
- Exchangeable Image File Format (Compressed) 2.0
- Exchangeable Image File Format (Compressed) 2.21
- Exchangeable Image File Format (Compressed) 2.3.x
Internal signatures
Raw JPEG
- Note
- SOI marker at BOF, EOI marker at EOF
Byte sequences
- Min Frag Length
- Absolute from BOF
- Offset
- 0
- Max offset
- None
- Byte Sequence
FFD8FF- Endianness
- None
- Min Frag Length
- Absolute from EOF
- Offset
- 0
- Max offset
- 65536
- Byte Sequence
FFD9- Endianness
- None
Photoshop JPEG
- Note
- BOF: SOI marker (FF|D8), APP14 - Photoshop Segment Marker (FF|ED), segment size {2}, Photoshop identification string, in ASCII: Photoshop 3.0. EOF: EOI marker (FF|D9) with a large offset due to the amount of photoshop metadata seen after the end of image marker in sample files.
Byte sequences
- Min Frag Length
- Absolute from BOF
- Offset
- 0
- Max offset
- 0
- Byte Sequence
FFD8FFED{2}50686F746F73686F7020332E30003842494D- Endianness
- None
- Min Frag Length
- Absolute from EOF
- Offset
- 0
- Max offset
- 16000
- Byte Sequence
FFD9- Endianness
- None
Changelog
-
Updated in V114
- Release date
- 22 August 2023
Raw JPEG Stream: Offset modified for the EOF signature as null value causing max-offset to be ignored. Submitted by Preservica.
-
Updated in V109
- Release date
- 1 November 2022
Raw JPEG Stream: Updated description and reference links, added extensions jif; jfif; jfi, and LoC identifier. Submitted by Digital Preservation Department, The National Archives (UK).
-
Updated in V75
- Release date
- 17 July 2014
Raw JPEG Stream: EOF offset increased. Submitted by Public Record Office of Northern Ireland.
-
Updated in V63
- Release date
- 29 August 2012
Raw JPEG Stream: Signature refined through PRONOM Research in collaboration with the National Library of New Zealand.
-
Updated in V62
- Release date
- 28 August 2012
Raw JPEG Stream: Existing signature refined through PRONOM Research.