Handleiding Denon S-5BD - Cara (pagina 90 van 98) (Engels)

498669

Verklein

Vergroot

Pagina terug

1/98

Pagina verder

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:

1. We don’t promise that this software works. (But if you ﬁnd any

bugs, please let us know!)

2. You can use this software for whatever you want. You don’t have

to pay us.

3. You may not pretend that you wrote this software. If you use

it in a program, you must acknowledge somewhere in your

documentation that you’ve used the IJG code.

In legalese:

The authors make NO WARRANTY or representation, either express

or implied, with respect to this software, its quality, accuracy,

merchantability, or ﬁtness for a particular purpose. This software is

provided “AS IS”, and you, its user, assume the entire risk as to its

quality and accuracy.

Permission is hereby granted to use, copy, modify, and distribute this

software (or portions thereof) for any purpose, without fee, subject

to these conditions:

(1) If any part of the source code for this software is distributed,

then this README ﬁle must be included, with this copyright

and no-warranty notice unaltered; and any additions, deletions,

or changes to the original ﬁles must be clearly indicated in

accompanying documentation.

(2) If only executable code is distributed, then the accompanying

documentation must state that “this software is based in part on

the work of the Independent JPEG Group”.

(3) Permission for use of this software is granted only if the user

accepts full responsibility for any undesirable consequences; the

authors accept NO LIABILITY for damages of any kind.

These conditions apply to any software derived from or based on the

IJG code, not just to the unmodiﬁed library. If you use our work, you

ought to acknowledge us.

Permission is NOT granted for the use of any IJG author’s name or

company name in advertising or publicity relating to this software or

products derived from it. This software may be referred to only as

“the Independent JPEG Group’s software”.

We speciﬁcally permit and encourage the use of this software as the

basis of commercial products, provided that all warranty or liability

claims are assumed by the product vendor.

ansi2knr.c is included in this distribution by permission of L. Peter

Deutsch, sole proprietor of its copyright holder, Aladdin Enterprises

of Menlo Park, CA.

ansi2knr.c is NOT covered by the above copyright and conditions,

but instead by the usual distribution terms of the Free Software

Foundation; principally, that you must include source code if you

redistribute it. (See the ﬁle ansi2knr.c for full details.) However,

since ansi2knr.c is not needed as part of any program generated

from the IJG code, this does not limit you more than the foregoing

paragraphs do.

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,

ltconﬁg, ltmain.sh). Another support script, install-sh, is copyright by

M.I.T. but is also freely distributable.

It appears that the arithmetic coding option of the JPEG spec is

covered by patents owned by IBM, AT&T, and Mitsubishi. Hence

arithmetic coding cannot legally be used without obtaining one or

more licenses. For this reason, support for arithmetic coding has

been removed from the free JPEG software.

(Since arithmetic coding provides only a marginal gain over

the unpatented Huffman mode, it is unlikely that very many

implementations will support it.)

So far as we are aware, there are no patent restrictions on the

remaining code.

The IJG distribution formerly included code to read and write GIF

ﬁles.

To avoid entanglement with the Unisys LZW patent, GIF reading

support has been removed altogether, and the GIF writer has been

simpliﬁed to produce “uncompressed GIFs”. This technique does not

use the LZW algorithm; the resulting GIF ﬁles are larger than usual,

but are readable by all standard GIF decoders.

We are required to state that

“The Graphics Interchange Format(c) is the Copyright property of

CompuServe Incorporated. GIF(sm) is a Service Mark property of

CompuServe Incorporated.”

REFERENCES

We highly recommend reading one or more of these references

before trying to 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.

(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 PostScript ﬁle containing a revised

version of Wallace’s article is available at ftp://ftp.uu.net/graphics/

jpeg/wallace.ps.gz. The ﬁle (actually a preprint for an article that

appeared in IEEE Trans. Consumer Electronics) omits the sample

images that appeared in CACM, but it includes corrections and some

added material. Note: the Wallace article is copyright ACM and IEEE,

and it may not be used for commercial purposes.

A somewhat less technical, more leisurely introduction to JPEG can

be found in “The Data Compression Book” by Mark Nelson and Jean-

loup Gailly, published by M&T Books (New York), 2nd ed. 1996, ISBN

1-55851-434-1. This book provides good explanations and example C

code for a multitude of compression methods including JPEG. It is

an excellent source if you are comfortable reading C code but don’t

know much about data compression in general. The book’s JPEG

sample code is far from industrial-strength, but when you are ready

to look at a full implementation, you’ve got one here...

The best full description of JPEG is the textbook “JPEG Still Image

Data Compression Standard” by William B. Pennebaker and Joan

L. Mitchell, published by Van Nostrand Reinhold, 1993, ISBN 0-442-

01272-1. Price US$59.95, 638 pp.

The book includes the complete text of the ISO JPEG standards (DIS

10918-1 and draft DIS 10918-2).

This is by far the most complete exposition of JPEG in existence, and

we highly recommend it.

The JPEG standard itself is not available electronically; you must

order a paper copy through ISO or ITU. (Unless you feel a need to

own a certiﬁed ofﬁcial copy, we recommend buying the Pennebaker

and Mitchell book instead; it’s much cheaper and includes a great

deal of useful explanatory material.)

In the USA, copies of the standard may be ordered from ANSI Sales

at (212) 642-4900, or from Global Engineering Documents at (800)

854-7179. (ANSI doesn’t take credit card orders, but Global does.)

It’s not cheap: as of 1992, ANSI was charging $95 for Part 1 and $47

for Part 2, plus 7% shipping/handling. The standard is divided into

two parts, Part 1 being the actual speciﬁcation, while Part 2 covers

compliance testing methods. Part 1 is titled “Digital Compression

and Coding of Continuous-tone Still Images, Part 1: Requirements

and guidelines” and has document numbers ISO/IEC IS 10918-

1, ITU-T T.81. Part 2 is titled “Digital Compression and Coding of

Continuous-tone Still Images, Part 2: Compliance testing” and has

document numbers ISO/IEC IS 10918-2, ITU-T T.83.

Some extensions to the original JPEG standard are deﬁned in JPEG

Part 3, a newer ISO standard numbered ISO/IEC IS 10918-3 and ITU-

T T.84. IJG currently does not support any Part 3 extensions.

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. A copy of the JFIF spec is available from:

Literature Department

C-Cube Microsystems, Inc.

1778 McCarthy Blvd.

Milpitas, CA 95035

phone (408) 944-6300, fax (408) 944-6314

A PostScript version of this document is available by FTP at ftp://ftp.

uu.net/graphics/jpeg/jﬁf.ps.gz. There is also a plain text version at

ftp://ftp.uu.net/graphics/jpeg/jﬁf.txt.gz, but it is missing the ﬁgures.

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 found in the TIFF 6.0 spec of 3-June-92 has a number of

serious problems.

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 “ofﬁcial” archive site for this software is ftp.uu.net (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 ﬁles that way.

Numerous Internet sites maintain copies of the UUNET ﬁles.

However, only ftp.uu.net is guaranteed to have the latest ofﬁcial

version.

You can also obtain this software in DOS-compatible “zip” archive

format from the SimTel archives (ftp://ftp.simtel.net/pub/simtelnet/

msdos/graphics/), or on CompuServe in the Graphics Support forum

(GO CIS:GRAPHSUP), library 12 “JPEG Tools”. Again, these versions

may sometimes lag behind the ftp.uu.net release.

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.org/faqs/

jpeg-faq/ and other news.answers archive sites, including the ofﬁcial

news.answers 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

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

PPM-format image ﬁles. In particular, it can convert PPM images to

and from a wide range of other formats, thus making cjpeg/djpeg

considerably more useful. The latest version is distributed by the

NetPBM group, and is available from numerous sites, notably ftp://

wuarchive.wustl.edu/graphics/graphics/packages/NetPBM/.

Unfortunately PBMPLUS/NETPBM is not nearly as portable as the

IJG software is; you are likely to have difﬁculty making it work on any

non-Unix machine.

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 ﬁles that are not compatible with our

library.

The root of the problem is that the ISO JPEG committee failed to

specify a concrete ﬁle format. Some vendors “ﬁlled in the blanks” on

their own, creating proprietary formats that no one else could read.

(For example, none of the early commercial JPEG implementations

for the Macintosh were able to exchange compressed ﬁles.)

The ﬁle format we have adopted is called JFIF (see 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 modiﬁed

LICENSE



Denon S-5BD - Cara Handleiding

Hulp nodig? Stel uw vraag in het forum

Misbruik melden

Product:

Spelregels forum

Abonneren

Ontvang uw handleiding per email

Stel vragen via chat aan uw handleiding

Andere handleiding(en) van Denon S-5BD - Cara

Uw handleiding is per email verstuurd. Controleer uw email

Er is een email naar u verstuurd om uw inschrijving definitief te maken.

U heeft geen emailadres opgegeven

Uw vraag is op deze pagina toegevoegd

Info