change.log Version-to-version change highlights.
Programmer and internal documentation:
libjpeg.txt How to use the JPEG library in your own programs.
- example.c Sample code for calling the JPEG library.
+ example.txt Sample code for calling the JPEG library.
structure.txt Overview of the JPEG library's internal structure.
coderules.txt Coding style rules --- please read if you contribute code.
assumed by the product vendor.
-The Unix configuration script "configure" was produced with GNU Autoconf.
-It is copyright by the Free Software Foundation but is freely distributable.
-The same holds for its supporting scripts (config.guess, config.sub,
-ltmain.sh). Another support script, install-sh, is copyright by X Consortium
-but is also freely distributable.
-
The IJG distribution formerly included code to read and write GIF files.
To avoid entanglement with the Unisys LZW patent (now expired), GIF reading
support has been removed altogether, and the GIF writer has been simplified
understand the innards of the JPEG software.
The best short technical introduction to the JPEG compression algorithm is
- Wallace, Gregory K. "The JPEG Still Picture Compression Standard",
- Communications of the ACM, April 1991 (vol. 34 no. 4), pp. 30-44.
+ Wallace, Gregory K. "The JPEG Still Picture Compression Standard",
+ Communications of the ACM, April 1991 (vol. 34 no. 4), pp. 30-44.
(Adjacent articles in that issue discuss MPEG motion picture compression,
applications of JPEG, and related topics.) If you don't have the CACM issue
handy, a PDF file containing a revised version of Wallace's article is
numbers ISO/IEC IS 10918-2, ITU-T T.83.
The JPEG standard does not specify all details of an interchangeable file
-format. For the omitted details we follow the "JFIF" conventions, revision
-1.02. JFIF 1.02 has been adopted as an Ecma International Technical Report
-and thus received a formal publication status. It is available as a free
-download in PDF format from
-http://www.ecma-international.org/publications/techreports/E-TR-098.htm.
-A PostScript version of the JFIF document is available at
-http://www.ijg.org/files/jfif.ps.gz. There is also a plain text version at
-http://www.ijg.org/files/jfif.txt.gz, but it is missing the figures.
+format. For the omitted details, we follow the "JFIF" conventions, revision
+1.02. JFIF version 1 has been adopted as ISO/IEC 10918-5 (05/2013) and
+Recommendation ITU-T T.871 (05/2011): Information technology - Digital
+compression and coding of continuous-tone still images: JPEG File Interchange
+Format (JFIF). It is available as a free download in PDF file format from
+https://www.iso.org/standard/54989.html and http://www.itu.int/rec/T-REC-T.871.
+A PDF file of the older JFIF 1.02 specification is available at
+http://www.w3.org/Graphics/JPEG/jfif3.pdf.
The TIFF 6.0 file format specification can be obtained by FTP from
ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.gz. The JPEG incorporation scheme
archive at rtfm.mit.edu: ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg-faq/.
If you don't have Web or FTP access, send e-mail to mail-server@rtfm.mit.edu
with body
- send usenet/news.answers/jpeg-faq/part1
- send usenet/news.answers/jpeg-faq/part2
-
-
-FILE FORMAT WARS
-================
-
-The ISO/IEC JTC1/SC29/WG1 standards committee (also known as JPEG, together
-with ITU-T SG16) currently promotes different formats containing the name
-"JPEG" which are incompatible with original DCT-based JPEG. IJG therefore does
-not support these formats (see REFERENCES). Indeed, one of the original
-reasons for developing this free software was to help force convergence on
-common, interoperable format standards for JPEG files.
-Don't use an incompatible file format!
-(In any case, our decoder will remain capable of reading existing JPEG
-image files indefinitely.)
+ send usenet/news.answers/jpeg-faq/part1
+ send usenet/news.answers/jpeg-faq/part2
+
+
+FILE FORMAT COMPATIBILITY
+=========================
+
+This software implements ITU T.81 | ISO/IEC 10918 with some extensions from
+ITU T.871 | ISO/IEC 10918-5 (JPEG File Interchange Format-- see REFERENCES).
+Informally, the term "JPEG image" or "JPEG file" most often refers to JFIF or
+a subset thereof, but there are other formats containing the name "JPEG" that
+are incompatible with the DCT-based JPEG standard or with JFIF (for instance,
+JPEG 2000 and JPEG XR). This software therefore does not support these
+formats. Indeed, one of the original reasons for developing this free software
+was to help force convergence on a common, interoperable format standard for
+JPEG files.
+
+JFIF is a minimal or "low end" representation. TIFF/JPEG (TIFF revision 6.0 as
+modified by TIFF Technical Note #2) can be used for "high end" applications
+that need to record a lot of additional data about an image.
TO DO
projects / platform / upstream / libjpeg-turbo.git / blobdiff