11
Information about software
This product uses the following software.
For information (copyright, etc) about each software, read the original sentences stated below.
■
About The Independent JPEG Group’s JPEG
software
The Independent JPEG Group’s JPEG software
README for release 6b of 27-Mar-1998
This distribution contains the sixth public release of the Independent JPEG Group’s free
JPEG software. You are welcome to redistribute this software and to use it for any
purpose, subject to the conditions under LEGAL ISSUES, below.
Serious users of this software (particularly those incorporating it into larger programs)
should contact IJG at [email protected] to be added to our electronic mailing list.
Mailing list members are notified of updates and have a chance to participate in
technical discussions, etc.
This software is the work of Tom Lane, Philip Gladstone, Jim Boucher, Lee Crocker,
Julian Minguillon, Luis Ortiz, George Phillips, Davide Rossi, Guido Vollbeding, Ge’
Weijers, and other members of the Independent JPEG Group.
IJG is not affiliated with the official ISO JPEG standards committee.
DOCUMENTATION ROADMAP
This file contains the following sections:
OVERVIEW
General description of JPEG and the IJG software.
LEGAL ISSUES
Copyright, lack of warranty, terms of distribution.
REFERENCES
Where to learn more about JPEG.
ARCHIVE LOCATIONS
Where to find newer versions of this software.
RELATED SOFTWARE
Other stuff you should get.
FILE FORMAT WARS
Software *not* to get.
TO DO
Plans for future IJG releases.
Other documentation files in the distribution are:
User documentation:
install.doc
How to configure and install the IJG software.
usage.doc
Usage instructions for cjpeg, djpeg, jpegtran, rdjpgcom,
and wrjpgcom.
*.1
Unix-style man pages for programs (same info as
usage.doc).
wizard.doc
Advanced usage instructions for JPEG wizards only.
change.log
Version-to-version change highlights.
Programmer and internal documentation:
libjpeg.doc
How to use the JPEG library in your own programs.
example.c
Sample code for calling the JPEG library.
structure.doc
Overview of the JPEG library’s internal structure.
filelist.doc
Road map of IJG files.
coderules.doc
Coding style rules --- please read if you contribute code.
Please read at least the files install.doc and usage.doc. Useful information can also be
found in the JPEG FAQ (Frequently Asked Questions) article. See ARCHIVE
LOCATIONS below to find out where to obtain the FAQ article.
If you want to understand how the JPEG code works, we suggest reading one or more of
the REFERENCES, then looking at the documentation files (in roughly the order listed)
before diving into the code.
OVERVIEW
This package contains C software to implement JPEG image compression and
decompression. JPEG (pronounced “jay-peg”) is a standardized compression method for
full-color and gray-scale images. JPEG is intended for compressing “real-world” scenes;
line drawings, cartoons and other non-realistic images are not its strong suit. JPEG is
lossy, meaning that the output image is not exactly identical to the input image. Hence
you must not use JPEG if you have to have identical output bits. However, on typical
photographic images, very good compression levels can be obtained with no visible
change, and remarkably high compression levels are possible if you can tolerate a low-
quality image. For more details, see the references, or just experiment with various
compression settings.
This software implements JPEG baseline, extended-sequential, and progressive
compression processes. Provision is made for supporting all variants of these processes,
although some uncommon parameter settings aren’t implemented yet. For legal reasons,
we are not distributing code for the arithmetic-coding variants of JPEG; see LEGAL
ISSUES. We have made no provision for supporting the hierarchical or lossless
processes defined in the standard.
We provide a set of library routines for reading and writing JPEG image files, plus two
sample applications “cjpeg” and “djpeg”, which use the library to perform conversion
between JPEG and some other popular image file formats. The library is intended to be
reused in other applications.
In order to support file conversion and viewing software, we have included considerable
functionality beyond the bare JPEG coding/decoding capability; for example, the color
quantization modules are not strictly part of JPEG decoding, but they are essential for
output to colormapped file formats or colormapped displays. These extra functions can
be compiled out of the library if not required for a particular application. We have also
included “jpegtran”, a utility for lossless transcoding between different JPEG processes,
and “rdjpgcom” and “wrjpgcom”, two simple applications for inserting and extracting
textual comments in JFIF files.
The emphasis in designing this software has been on achieving portability and
flexibility, while also making it fast enough to be useful. In particular, the software is not
intended to be read as a tutorial on JPEG. (See the REFERENCES section for
introductory material.) Rather, it is intended to be reliable, portable, industrial-strength
code. We do not claim to have achieved that goal in every aspect of the software, but we
strive for it.
We welcome the use of this software as a component of commercial products. No
royalty is required, but we do ask for an acknowledgement in product documentation, as
described under LEGAL ISSUES.
LEGAL ISSUES
In plain English:
Notice for Windows Media DRM
The Certified For Windows Vista logo, Windows Media and the Windows logo are trademarks or registered trademarks of Microsoft Corporation in the
United States and/or other countries.
Content providers are using the digital rights management technology for Windows Media contained in this device (WMDRM) to protect the integrity of
their content (Secure Content) so that their intellectual property, including copyright, in such content is not misappropriated.
This device uses WM-DRM software to play Secure Content (WM-DRM Software).
If the security of the WM-DRM Software in this device has been compromised, owners of Secure Content (Secure Content Owners) may request that
Microsoft revoke the WM-DRM Software’s right to acquire new licenses to copy, display and/or play Secure Content. Revocation does not alter the WM-
DRM Software’s ability to play unprotected content. A list of revoked WM-DRM Software is sent to your device whenever you
download a license for Secure Content from the Internet or from a PC. Microsoft may, in conjunction with such license, also download revocation list
onto your device on behalf of Secure Content Owners.
Note concernant Windows Media DRM
Le logo Certified For Windows Vista logo, Windows Media et le logo Windows sont des marques commerciales ou des marques déposées de Microsoft
Corporation aux États-Unis et/ou dans d’autres pays.
Les fournisseurs de contenu ont recours à la technologie de gestion des droits numériques pour Windows Media (“WM-DRM” pour Windows Media
Digital Rights Management) contenue dans le présent appareil pour protéger l’intégrité de leur contenu (le “Contenu Sécurisé ” ou Secure Content en
anglais) et ce afin d’empêcher toute atteinte à leurs droits de propriété intellectuelle, y compris leurs droits d’auteur, sur ce contenu. Cet appareil utilise le
logiciel WM-DRM pour lire du Contenu Sécurisé (“le Logiciel WM-DRM”). Si la sécurité du Logiciel WM-DRM dans le présent appareil a été violée,
Microsoft peut révoquer (soit de son propre chef soit à la demande des propriétaires de Contenu Sécurisé (“Propriétaires de Contenu Sécurisé”)) le droit
du Logiciel WM-DRM à acquérir de nouvelles autorisations de copier, afficher et/ou lire du Contenu Sécurisé. La révocation n’a aucune incidence sur la
capacité du Logiciel WM-DRM à lire du contenu non protégé. Une liste des Logiciels WM-DRM révoqués est envoyée sur votre appareil chaque fois que
vous téléchargez à partir d’Internet ou d’un PC une licence de Contenu Sécurisé. Microsoft peut également, en association avec cette licence, télécharger
des listes de révocation sur votre appareil au nom des Propriétaires de Contenu Sécurisé.