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SPIFF, Still Picture Interchange File Format
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Format Description Properties
• ID: fdd000019
• Short name: SPIFF
• Content categories: still image
• Format category: File format
• Last significant update: 2007-02-08
• Draft status: Full
Identification and description ![Explanation of format description terms](info.gif)
Full name | Annex F of ISO/IEC 10918-3 (Part 3 of the JPEG_DCT specification). Still Picture Interchange File Format (SPIFF). |
Description |
File format that enables JPEG and JBIG (bitonal) bitstreams to
be exchanged between a wide variety of platforms and applications. According to the specification, SPIFF "is designed to incorporate functionality found in some (ad hoc) image file formats (such as JFIF) . . . . it is intended that transcoding between any of these file formats and SPIFF should be simple." (p. 39) May contain a profile identifier to distinguish, say, baseline from progressive-encoded images. |
Production phase | May be used in initial-state picture creation; often used for middle- and final-state archiving or end-user delivery. |
Relationship to other formats | |
May contain | JPEG_DCT_BL, JPEG DCT Compression Encoding, Baseline |
May contain | JPEG_DCT_EXT, JPEG DCT Compression Encoding, Extensions |
May contain | JBIG1, JBIG1 Bitonal Image Encoding |
May contain | JBIG2, JBIG2 Bitonal Image Encoding |
May contain |
MR (Modified READ) and MMR (Modified Modified READ) compression, not documented at this Web site; MMR is used by ITU_G4, ITU-T "Group 4" FAX Compression (T.6) |
Local use ![Explanation of format description terms](info.gif)
LC experience or existing holdings | None. |
LC preference | The Library's general preference for still image "masters" is for uncompressed bitstreams, and rich metadata is always welcome. Thus TIFF_UNC_EXIF and TIFF_UNC are preferred. For images only available in lossy compressed form, JPEG_DCT is acceptable; preferred file formats for JPEG_DCT include JPEG_EXIF (rich metadata) and JFIF. Meanwhile, J2K_C_LSY (JPEG 2000 Part 1, Core Coding, Lossy Compression) is an emerging preference for compressed bitmapped still images. |
Sustainability factors ![Explanation of format description terms](info.gif)
Disclosure | Fully disclosed. Developed by the Joint Photographic Experts Group (JPEG), formally known as ISO/IEC JTC 1/SC 29/WG 10. |
Documentation |
ISO/IEC 10918-3 (part 3), Annex F. Also published as ITU-T Recommendation T.84. |
Adoption | Appears not to be widely adopted; most producers create JFIF files, which conform to the general file interchange specifications in ISO/IEC 10918-1 (part 1). |
Licensing and patent claims | None on the file format; see JPEG_DCT for patent claims on JPEG encoding. |
Transparency | Transparent. |
Self-documentation |
Limited techical metadata is provided in a file header (specification pp. 41-45). The specification also lists a set of descriptive-data tags (e.g., title, creator, copyright, etc.) in a discussion of directory entries. (pp. 45 ff.) See also the useful explanations in the SPIFF article in the Encyclopedia of Graphics File Formats |
External dependencies | None. |
Technical protection considerations | None. |
Quality and functionality factors ![Explanation of format description terms](info.gif)
Normal rendering for still images | Good support. |
Clarity (support for high image resolution) |
See JPEG_DCT_BL and JPEG_DCT_EXT. SPIFF marks its files with the gamma value, in contrast to JFIF. The maximum image size if 4Gx4G pixles or 64Kx64K pixels for non-tiled baseline JPEG. According to the SPIFF article in the Encyclopedia of Graphics File Formats, SPIFF files can support the following forms of compression: MR, MMR, JBIG (certainly JBIG1 and possibly JBIG2—editor), JPEG, and uncompressed. |
Color maintenance | The header does not support the recording of an ICC profile for the capture device.1 The header can contain a code for color spaces, including bi-level, three YCbCr spaces associated with ITU-T specifications BT 709 and BT 601-1, grayscale, PhotoYCC, RGB, CMY, CMYK, YCCK, and CIELab (specification, p. 44); the list does not include sRGB.2 |
Support for graphic effects and typography | No support for vector graphics. |
Functionality beyond normal image rendering | Can store thumbnails along with a larger image. |
File type signifiers ![Explanation of format description terms](info.gif)
Tag type | Value | Note |
Filename Extension | jpg, jpeg | From the SPIFF article in the Encyclopedia of Graphics File Formats: "The SPIFF specification does not define a standard file extension . . . for SPIFF files. IJG [Independent JPEG Group] recommends that the extension ".JPG" . . . be used for SPIFF files containing lossy (DCT) JPEG-compressed data."3 |
Filename Extension | spf, spiff |
From the SPIFF article in the Encyclopedia of Graphics File Formats: "IJG recommends that the extension . . . ".SPF" be used for all [non-JPEG] variants of SPIFF. (Of course, the JBIG community might prefer a ".JBG" extension for SPIFF-JBIG files.)" Meanwhile, the File Extension Source (as consulted in February 2007), in an "unverified" entry, offers the extension spiff. |
Internet Media Type | image/jpeg | From the SPIFF article in the Encyclopedia of Graphics File Formats: "IJG recommends that . . . 'JPEG' type indicator be used for SPIFF files containing lossy (DCT) JPEG-compressed data." |
Magic numbers | Hex: FF D8 FF E8 xx xx 53 50 49 46 46 00 ASCII: ÿØÿè..SPIFF | Derived from the specification. |
Notes ![Explanation of format description terms](info.gif)
General | Paraphrased from Vanryper Murray's Encylopedia of Graphics File Formats (O'Reilly & Assoc, 1994, ISBN 1565920589): The JPEG bitstream stores 16-bit word values in big-endian format. JPEG data in general is stored as a stream of blocks, and each block is identified by a marker value. The first two bytes of every JPEG stream are the Start Of Image (SOI) marker values FFh D8h. In a JFIF-compliant file there is a JFIF APP0 (Application) marker, immediately following the SOI, which consists of the marker code values FFh E0h and the characters JFIF in the marker data, as described in the next section. In addition to the JFIF marker segment, there may be one or more optional JFIF extension marker segments, followed by the actual image data. |
History | |
Format specifications ![Explanation of format description terms](info.gif)
URLs
Print
• ISO/IEC 10918-3 (part 3), Annex F.
Useful references
URLs
•
JHOVE's JPEG page (http://hul.harvard.edu/jhove/jpeg-hul.html)
•
SPIFF article in the
Encyclopedia of Graphics File Formats (http://www.fileformat.info/format/spiff/)
Print
• Murray, Vanryper.
Encylopedia of Graphics File Formats, Sebastopol, California: O'Reilly & Assoc, 1994. (ISBN 1565920589)
Last Updated: Wednesday, 07-Mar-2007 12:40:16 EST