A PostScript version of this document is available by FTP at ftp://ftp.uu.net/graphics/jpeg/j.ps.gz. There is also a plain text version at ftp://ftp.uu.net/graphics/jpeg/j.txt. gz, but it is missing the
The TIFF 6.0
FTP from ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.gz. The JPEG incorporation scheme found in the TIFF 6.0 spec of
IJG does not recommend use of the TIFF 6.0 design (TIFF Compression tag 6).
Instead, we recommend the JPEG design proposed by TIFF Technical Note #2 (Compression tag 7). Copies of this Note can be obtained from ftp.sgi.com or from ftp:// ftp.uu.net/graphics/jpeg/. It is expected that the next revision of the TIFF spec will replace the 6.0 JPEG design with the Note’s design.
Although IJG’s own code does not support TIFF/JPEG, the free libtiff library uses our library to implement TIFF/ JPEG per the Note. libtiff is available from ftp://ftp.sgi. com/graphics/tiff/.
ARCHIVE LOCATIONS The “of
(Internet address 192.48.96.9). The most recent released version can always be found there in directory graphics/ jpeg. This particular version will be archived as ftp://ftp. uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.
If you don’t have direct Internet access, UUNET’s archives are also available via UUCP; contact help@uunet.uu.net for information on retrieving .
Numerous Internet sites maintain copies of the UUNET
,only ftp.uu.net is guaranteed to have the latest of
You can also obtain this software in
The JPEG FAQ (Frequently Asked Questions) article is a useful source of general information about JPEG. It is updated constantly and therefore is not included in this distribution. The FAQ is posted every two weeks to Usenet newsgroups comp.graphics.misc, news.answers, and other groups.
It is available on the World Wide Web at http://www.faqs.
edu: ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg- faq/.
If you don’t have Web or FTP access, send
send
RELATED SOFTWARE
Numerous viewing and image manipulation programs now support JPEG. (Quite a few of them use this library to do so.) The JPEG FAQ described above lists some of the more popular free and shareware viewers, and tells where to obtain them on Internet.
If you are on a Unix machine, we highly recommend Jef Poskanzer’s free PBMPLUS software, which provides many useful operations on
Unfortunately PBMPLUS/NETPBM is not nearly as portable as the IJG software is; you are likely to have dif making it work on any
A different free JPEG implementation, written by the PVRG group at Stanford,
is available from ftp://havefun.stanford.edu/pub/jpeg/. This program is designed for research and experimentation rather than production use; it is slower, harder to use, and less portable than the IJG code, but it is easier to read and modify. Also, the PVRG code supports lossless JPEG, which we do not. (On the other hand, it doesn’t do progressive JPEG.)
FILE FORMAT WARS
Some JPEG programs produce with our library.
The root of the problem is that the ISO JPEG committee failed to specify a concrete
“
formats that no one else could read. (For example, none of the early commercial JPEG implementations for the Macintosh were able to exchange compressed
The
REFERENCES). This format has been agreed to by a number of major commercial JPEG vendors, and it has become the de facto standard. JFIF is a minimal or “low end” representation.
We recommend the use of TIFF/JPEG (TIFF revision 6.0 as modiechnical Note #2) for “high end” applications that need to record a lot of additional data about an image. TIFF/JPEG is fairly new and not yet widely supported, unfortunately.
The upcoming JPEG Part 3 standard de called SPIFF.
SPIFF is interoperable with JFIF, in the sense that most JFIF decoders should be able to read the most common variant of SPIFF. SPIFF has some technical advantages over JFIF, but its major claim to fame is simply that it is an of
it is unclear whether SPIFF will supersede JFIF or whether JFIF will remain the
(In any case, our decoder will remain capable of reading JFIF inde.)
Various proprietary compression also exist.
We have little or no sympathy for the existence of these formats. Indeed, one of the original reasons for developing this free software was to help force convergence on common, open format standards for JPEG ’t use
aproprietary
TO DO
The major thrust for v7 will probably be improvement of visual quality.
The current method for scaling the quantization tables is known not to be very good at low Q values. We also intend to investigate block boundary smoothing, “poor man’s variable quantization”, and other means of improving
In future versions, we are considering supporting some of the upcoming JPEG Part 3 extensions
As always, speeding things up is of great interest. Please send bug reports, offers of help, etc. to
nExhibit-F
COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
If you modify libpng you may insert additional notices immediately following this sentence.
libpng version 1.2.6, August 15, 2004, is Copyright (c) 2004 Glenn
Cosmin Truta
libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are Copyright (c)
and with the following additions to the disclaimer:
There is no warranty against interference with your enjoyment of the library or against infringement. There is no warranty that our efforts or the library will ful
library is provided with all faults, and the entire risk of satisfactory quality, performance, accuracy, and effort is with the user.
libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are Copyright (c) 1998, 1999 Glenn Randers- Pehrson, and are distributed according to the same disclaimer and license as
Tom Lane
Glenn
libpng versions 0.89, June 1996, through 0.96, May 1997, are Copyright (c) 1996, 1997 Andreas Dilger Distributed according to the same disclaimer and license as libpng- 0.88, with the following individuals added to the list of Contributing Authors:
John Bowler
Kevin Bracey
Sam Bushell Magnus Holmgren Greg Roelofs Tom Tanner
libpng versions 0.5, May 1995, through 0.88, January 1996, are Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
For the purposes of this copyright and license,“Contributing Authors” is de
Andreas Dilger
Dave Martindale
Guy Eric Schalnat Paul Schmidt Tim Wegner
The PNG Reference Library is supplied “AS IS”. The Contributing Authors and Group 42, Inc. disclaim all warranties, expressed or implied, including, without limitation, the warranties of merchantability and of
for any purpose. The Contributing Authors and Group 42, Inc. assume no liability for direct, indirect, incidental, special, exemplary, or consequential damages, which may result from the use of the PNG Reference Library, even if advised of the possibility of such damage.
Permission is hereby granted to use, copy, modify, and distribute this source code, or portions hereof, for any purpose, without fee, subject to the following restrictions:
1.The origin of this source code must not be misrepresented.
2.Altered versions must be plainly marked as such and must not be misrepresented as being the original source.
3.This Copyright notice may not be removed or altered from any source or altered source distribution.
The Contributing Authors and Group 42, Inc. speci permit, without fee, and encourage the use of this source code as a component to supporting the PNG
in commercial products. If you use this source code in a product, acknowledgment is not required but would be appreciated.
A “png_get_copyright” function is available, for convenient use in “about” boxes and the like: printf(“%s”,png_get_ copyright(NULL)); Also, the PNG logo (in PNG format, of course) is supplied in the .png” and “pngbar.
jpg (88x31) and “pngnow.png” (98x31). Libpng is OSI Certi
Certi
Source Initiative.
Glenn
nExhibit-G
Copyright (c) 2001,2003 Keith Packard
Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Keith Packard not be used in advertising or publicity pertaining to distribution of the software without speci
Keith Packard makes no representations about the suitability of this software for any purpose. It is provided “as is” without express or implied warranty.
KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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